APPENDIX A Laboratory Reports for the Development of a Chemical

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APPENDIX A

Laboratory Reports for the Development of a Chemical Stain to Identify Arsenic-Treated Wood

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Testing Shredded Wood Samples DATES OF EXPERIMENT: June 4, 2004 to June 7, 2004 PURPOSE This experiment was performed to determine the possibility of testing shredded wood samples for arsenic by applying ammonium molybdate and stannous chloride reagents to its surface. Other factors considered in this experiment were the reaction time it takes to turn color, color intensity, and combining the ammonium molybdate and stannous chloride reagents before adding it to the wood. ADDITIONAL REAGENTS • Combined ammonium molybdate and stannous chloride reagent

o 1 mL stannous chloride reagent was added to 8 mL ammonium molybdate reagent. o NOTE: Stannous chloride reagent was very viscous and difficult to measure out exactly

1 mL; therefore, it was easier to add the stannous chloride reagent drop wise. Must maintain the 8:1 ratio of ammonium molybdate to stannous chloride.

PRELIMINARY SAMPLE TREATMENT • To 100 mL standard phosphate solution containing not more than 200 µg P and free from

color and turbidity, 0.05 mL (1 drop) phenolphthalein indicator was added. o If sample turned pink, a strong acid solution was added drop wise to discharge the color. o If more than 0.25 mL (5 drops) was required, a smaller sample was taken and diluted to

100 mL with distilled water after first discharging the pink color with acid. *NOTE: Rate of color development and intensity of color depend on temperature of the final

solution. Each 1°C increase producing about 1% increased in color. Hence, the samples, standards, and reagents were held within 2°C of one another and in the temperature range between 20°C to 30°C.

PROCEDURE There were five groups in this experiment. The last three groups of samples were tested using the stannous chloride method. Each group consisted of a sample of Standard Phosphate Solution and shredded wood samples of Untreated Wood, 4.0 kg/m3 CCA-Treated, 9.6 kg/m3 CCA-Treated, 40 kg/m3 CCA-Treated, and Weathered Wood. • Group 1 – Blank

o Standard Phosphate Solution (10 mL) o Shredded Wood Samples

Drops of phenolphthalein were randomly placed over the surface of the shredded wood to determine if it was within the pH range of the experiment.

• Group 2 – Added 1 N NaOH *This was performed merely to serve as a comparison for the pink color that would appear if pH > 9. o Standard Phosphate Solution (10 mL)

1 mL of 1 N NaOH was added and mixed. 1 drop of phenolphthalein was added and mixed. The pink color and color intensity were noted.

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o Shredded Wood Samples Drops of 1 N NaOH were randomly placed over the surface of the shredded wood. Drops of phenolphthalein were randomly placed over the surface of the shredded

wood. The pink color and color intensity were noted.

• Group 3 – Ammonium molybdate and stannous chloride reagents separated 8:1 o Standard Phosphate Solution (10 mL)

8 drops of ammonium molybdate reagent were added and mixed. 1 drop of stannous chloride reagent was added and mixed. The blue color and color intensity were noted.

o Shredded Wood Samples Drops of ammonium molybdate were randomly placed over the surface of the

shredded wood in excess amounts. The reaction time started once random drops of stannous chloride were added to the

surface of the shredded wood in smaller amounts. The reaction time stopped once a color change occurred. The reaction time, color, and color intensity were recorded

• Group 4 – Ammonium molybdate and stannous chloride reagents separated 1:1 o Standard Phosphate Solution (10 mL)

N/A o Shredded Wood Samples

Drops of ammonium molybdate were randomly placed over the surface of the shredded wood.

The reaction time started once random drops of stannous chloride were added to the surface of the shredded wood in equal amounts.

The reaction time stopped once a color change occurred. The reaction time, color, and color intensity were recorded.

• Group 5 – Ammonium molybdate and stannous chloride reagents combined o Standard Phosphate Solution (10 mL)

N/A o Shredded Wood Samples

The reaction time started once random drops of the combined ammonium molybdate and stannous chloride reagents were added to the surface of the shredded wood.

The reaction time stopped once a color change occurred. The reaction time, color, and color intensity were recorded.

The color and color intensity were recorded after 3 days.

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DATA

Shredded Wood Samples Description Group

# Standard

Phosphate Untreated 4.0 kg/m3 CCA

9.6 kg/m3 CCA

40 kg/m3 CCA Weathered

Phenolphthalein 1 colorless nc nc nc nc nc

Added 1N NaOH 2

initially intense pink, faded to light pink over

several minutes

intense pink intense pink

intense pink

intense pink

intense pink

Reagents Separated 8:1 3 intense blue

[instant]

intense blue [instant],

faded after 4 m

intense blue

[instant], faded

after 6 m

blue [2 m]

blue [10 m]

no blue [>30 m]

Reagents Separated 1:1 4 N/A

intense blue [instant],

faded after 4 m

intense blue

[instant], faded

after 6 m

blue [2 m]

blue [10 m]

no blue [>30 m]

Reagents Combined 5 N/A faint blue

[instant] faint blue [instant]

faint blue [instant]



Table A-1: Color, Color Intensity, and Time of Sample Reactions

Figure A-1: Phosphate Solutions

Phenolphthalein

1N NaOH

Reagents Separated

8:1

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Figure A-2: Reagents Separated 8:1 (above) and 1:1 (below)


# Standard

Phosphate Untreated 4.0 kg/m3 CCA 9.6 kg/m3 CCA 40 kg/m3 CCA Weathered Phenolphthalein 1 colorless nc nc nc nc nc

Added 1N NaOH 2

initially intense pink, faded to light pink over

several minutes

amount of pink color

decreased, but not intensity








decreased, but not

intensity

Reagents Separated 8:1 3 nc

blue color faded

completely; med & dk

brown color

blue color faded


brown color

blue color faded


brown color

intense blue color; med & dk

brown color

intense blue color; med &

dk brown color

Reagents Separated 1:1 4 N/A

blue color faded

completely; lt & med brown

color

blue color faded

completely; lt, med & dk

brown color

blue color faded

completely; lt, med & dk

brown color

intense blue color; med to

dk brown color

intense blue color; med to

dk brown color

Reagents Combined 5 N/A med brown med brown med & dk

brown; blue blue & intense

blue dk brown &

blue Table A-2: Color and Color Intensity of Sample After 3 Days

Untreated 4.0 kg/m3 CCA 9.6 kg/m3 CCA 40 kg/m3 CCA Weathered

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Figure A-3: After 3 Days – Reagents Separated 8:1 (above) and 1:1 (below)

Figure A-4: After 3 Days – Reagents Combined

CONCLUSION Combining the ammonium molybdate and stannous chloride reagents resulted in a dark blue-green colored solution that appeared almost black. This caused some difficulty when trying to discern if the reaction was actually occurring (any arsenate in the wood reacted to the solution and changed blue) or if the wood did not yet absorb the solution. On the other hand, applying the reagents separately to a solid was complicated because preserving the 8:1 ratio was difficult. Future experiments could study the ratio of ammonium molybdate to stannous chloride to determine what is necessary. The absorption of the reagents was a large problem. Because the wood was very heterogeneous, it was difficult to preserve the ratio due to differing absorption rates. Additionally, the stannous chloride reagent was a very viscous solution. Applying the reagents separately did not give an even mix of the two reagents. When the phenolphthalein was applied, however, it was absorbed immediately. The untreated wood reacted similar in color and time to the 4.0 kg/m3 CCA-treated wood. Various interferences, suspected arsenate or phosphate, could have caused the untreated wood to react. Future experimentation may look into a different application method for more uniform distribution of the reagents (shredded wood in solution), increasing the absorption rates (40 kg/m3 CCA-treated wood fully absorbed the molybdate reagent at 14 minutes), introducing a catalyst (which implies determining what is the slow step of the reaction), determining the importance of pH, reaction of alternative treated wood (ACQ, CBA, CC, and CDDC). One possible consideration is to use the stannous chloride stain along with the PAN indicator.

9.6 kg/m3 CCA 40 kg/m3 CCA Weathered 4.0 kg/m3 CCA Untreated


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Testing Shredded Wood Samples in Solution DATES OF EXPERIMENT: June 10, 2004 to June 11, 2004 PURPOSE This experiment was performed to determine the possibility of testing shredded wood samples for arsenic by mixing them in a solution of ammonium molybdate and stannous chloride reagents in a 8:1 ratio. Other factors considered in this experiment were the reaction time it takes to turn color, color intensity, and combining the ammonium molybdate and stannous chloride reagents before adding it to the wood. PROCEDURE Two sets of blanks were prepared. • Reagents Separated

o 8 drops of ammonium molybdate reagent were added to 10 mL of standard phosphate solution.

o 1 drop of stannous chloride was added and mixed. • Reagents Combined

o 8 drops of ammonium molybdate reagent were added to 10 mL of standard phosphate solution.

o 1 drop of stannous chloride was added and mixed. Five groups of samples were tested. Each group tested shredded wood samples in the following order: Untreated Wood, 4.0 kg/m3 CCA-Treated Wood, 9.6 kg/m3 CCA-Treated Wood, 40 kg/m3 CCA-Treated Wood, and Weathered Wood. • Groups 1 and 2 – Soak, Reagents Separated

o 0.5 g of shredded wood was added to 10 mL of distilled water. o The wood was soaked for 30 minutes, with occasional mixing. o 8 drops of ammonium molybdate reagent were added and mixed. o Time started once 1 drop of stannous chloride reagent was added. It was mixed

occasionally. o Time stopped when the sample turned color. o The time, color, and color intensity were recorded.

• Group 3 – Soak, Reagents Combined o 0.5 g of shredded wood was added to 10 mL of distilled water. o The wood was soaked for 30 minutes, with occasional mixing. o Time started once 9 drops of the combined reagent was added. It was mixed

occasionally. o Time stopped when the sample turned color. o The time, color, and color intensity were recorded.

• Group 4 – Wood Last, Reagents Separated o To 10 mL of distilled water, 8 drops of ammonium molybdate reagent were added and 1

of drop stannous chloride reagent, and mixed. o Time started once 0.5 g of shredded wood was added. It was mixed occasionally. o Time stopped when the sample turned color. o The time, color, and color intensity were recorded.

• Group 5 – Wood Last, Reagents Combined

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o To 10 mL of distilled water, 9 drops of combined reagent were added and mixed. o Time started once 0.5 g of shredded wood was added. It was mixed occasionally. o Time stopped when the sample turned color. o The time, color, and color intensity were recorded.

The color and color intensity of the samples were recorded after one day. DATA

Blank Color Reagents Separated colorless Reagents Combined faint yellow tint

Table A-3: Color Description of Blanks The scale used for describing the intensity of a blue color was as follows: clear → faint blue tint → light blue → medium blue → blue → intense blue → dark blue → black

LOWEST HIGHEST


Figure A-5: Blanks, Reagents Separated (left) and Reagents Combined (right)


# Untreated 4.0 kg/m3 CCA

9.6 kg/m3 CCA


Soak, Reagents Separated 1 1 lt. greenish-blue

[instant] lt. blue [instant]

med. blue [instant]

blue [instant]

lt. to med. blue [instant]

Soak, Reagents Separated 2 2 lt. greenish-blue

[instant] lt. blue [instant]

med. blue [instant]

blue [instant]

lt. to med. blue [instant]

Soak, Reagents Combined 3 faint blue tint

[44 m] med. blue

[17 m] blue

[6 m 20 s] intense blue

[5 m] med. blue

[17 m] Wood Last, Reagents Separated 4 lt. greenish-blue

[30 s] lt. blue

[1 m 20 s] med. blue

[40 s] blue [30 s]

lt. blue [40 s]

Wood Last, Reagents Combined 5 faint blue tint

[22 m 50 s] lt. blue [17 m]

med. blue [8 m 15 s]

blue [3 m]

lt. blue [7 m 45 s]

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Figure A-6: Soak, Reagents Separated 1 and 2

Figure A-7: Soak, Reagents Combined Initial (above) and Final (below)

Figure A-8: Comparison of Soak, Reagents Separated (rear) and Combined (front)





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Figure A-9: Wood Last, Reagents Separated

Figure A-10: Wood Last, Reagents Combined

Figure A-11: Comparison of Wood Last, Reagents Separated (rear) and Combined (front)




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Shredded Wood Samples

Description Group # Untreated 4.0 kg/m3 CCA 9.6 kg/m3 CCA 40 kg/m3

CCA Weathered

Soak, Reagents Separated 1 1 lt. greenish-

blue lt. blue med. blue blue lt. greenish-blue

Soak, Reagents Separated 2 2 lt. greenish-

blue lt. blue med. blue blue lt. greenish-blue

Soak, Reagents Combined 3 faint yellow tint blue intense blue intense blue intense blue

Wood Last, Reagents Separated 4 lt. greenish-

blue blue blue intense blue lt. greenish-blue

Wood Last, Reagents Combined 5 faint yellow tint blue intense blue intense blue blue

Table A-5: Color and Color Intensity of Samples After 1 Day

Figure A-12: After 1 Day – Soak, Reagents Separated 1 and 2

Figure A-13: After 1 Day – Soak, Reagents Combined



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Figure A-14: After 1 Day – Comparison of Soak, Reagents Separated (rear) and Combined

(front)

Figure A-15: After 1 Day – Wood Last, Reagents Separated

Figure A-16: After 1 Day – Wood Last, Reagents Combined




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Figure A-17: After 1 Day – Comparison of Wood Last, Reagents Separated (rear)

and Combined (front)

Figure A-18: After 1 Day – Comparison of Untreated Wood Samples

CONCLUSION From this experiment, we concluded that soaking the shredded wood for 30 minutes was not required for the stannous chloride method to detect the presence of arsenate, as shown by the results from adding the wood last. Future options included decreasing the soaking time, decreasing the amount of wood measured used, or increasing the amount of distilled water. However, it is important to keep in mind that the intensity of color depends on the concentration of arsenate. Additionally, by combining the reagents before adding it to the sample fulfilled the purpose of this research better. The untreated wood continued to react when the reagents were added separately in high similarity to the reaction that occurred with the 4.0 kg/m3 CCA-treated wood. This is problematic because of the color similarity witnessed, which makes it difficult to see the difference between untreated wood and CCA-treated wood. Further improvements to this experiment would be to determine the ratio of ammonium molybdate reagent to stannous chloride reagent that will give the best results. The next steps may be to determine the shelf life of the solution (distilled water, ammonium molybdate, and stannous chloride) and to develop a color scale of positive arsenate concentration. Applying this method to a dipstick method may be another option, in which case, the experiment may depend on being able to fix the reagents onto a dipstick and to develop a color scale. This dipstick

Soak, Reagents Separated

Soak, Reagents Separated

Soak, Reagents Combined

Wood Last, Reagents Separated

Wood Last, Reagents Combined


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method would be different from others because it would not detect arsine gas, but arsenate in solution. Finally, the most ideal application of this method would be to develop a stain that could be applied directly onto whole wood and to minimize the reaction time. However, quicker absorption of the stain on the wood is still a large concern. Determining why the combined reagents react to the CCA-treated wood and not the untreated (or at least to much lesser degree) is crucial.

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Atomic Absorption (AA) Analysis for Arsenic in Sample Solutions for Stannous Chloride Dissolution Method

DATE OF EXPERIMENT: June 11, 2004 PURPOSE This experiment was performed to determine the possible presence of arsenic in untreated shredded wood, which may be an explanation why the untreated wood solution reacted in previous experiments (“Testing Shredded Wood Samples” and “Testing Shredded Wood Samples in Solution”). Only the solutions obtained from the Untreated Wood and 4.0 kg/m3 CCA-treated wood samples were analyzed in the AA spectrometer. PREPARATION OF SAMPLES FOR AA • Untreated Wood

o 2.5 g shredded wood were added to 50 mL distilled water. o The wood was soaked for 30 minutes, and mixed occasionally. o Enough solution was filtered for AA analysis. The filtrate was used for AA analysis.

• 4.0 kg/m3 CCA-Treated Wood o 2.5 g shredded wood was added to 50 mL distilled water. o The wood was soaked for 30 minutes, and mixed occasionally. o Enough solution was filtered for AA analysis. The filtrate was used for AA analysis.

AA ANALYSIS PERFORMED BY: Tomoyuki Shibata, M.S. DATA

Wood Sample Arsenic Concentration (µg/L or ppb)

Untreated <1 4.0 kg/m3 CCA >500 (calibration range)

Table A-6: AA Results of Samples CONCLUSION The untreated wood sample did not contain arsenic; therefore, there must be some other interference that caused it to react with the stannous chloride method, most likely phosphate. Further analysis into this experiment would be to test the filtrate using the “Testing Shredded Wood Samples in Solution” with stannous chloride (both separate and combined reagents) to ensure the presence of an interference giving a positive result. FOLLOW-UP June 8, 2005: Another AA analysis was performed by soaking 5.0 g 4.0 kg/m3 CCA-treated

sawdust in 100 mL distilled water for 30 minutes. The sample was filtered and the filtrate was diluted to 1:100 with distilled water. AA analysis of the diluted sample presented a mean arsenic concentration of 55.22 µg/L, resulting in an actual arsenic concentration of 5.5 mg/L (5522 µg/L). The actual arsenic concentration is that found in the sample vials of new 4.0 kg/m3 CCA-treated sawdust using the stannous chloride stain dissolution method.

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Therefore, arsenic standards should begin around 5 mg/L and be diluted further in order to establish the MDL of the stannous chloride stain dissolution method.

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Testing Sawdust Samples of Alternative Treated Woods in Solution DATES OF EXPERIMENT: July 8, 2004 to July 9, 2004 PURPOSE This experiment was performed to determine if the stannous chloride Standard Methods procedure, which was designed to detect the presence of phosphate, would be specific for detecting arsenate. Because PAN indicator, the current stain for quickly detecting CCA-treated wood, detects for copper, it shows a false positive for arsenic in some alternative treated woods. The stannous chloride method was tested to determine if it also reacted with any alternative treated woods. Other factors considered in this experiment were the reaction time it takes to turn color and the color intensity before and after the reaction. PROCEDURE Two trials were performed for each wood type: Untreated Wood, CC-Treated Wood, CDDC-Treated Wood, CBA-Treated Wood, ACQ-Treated Wood, Borate-Treated Wood, and CCA-Treated Wood. The following procedure was used for each sawdust sample: • To 10 mL of distilled water, 9 drops of the combined ammonium molybdate/stannous

chloride reagent were added and mixed. • Time started once 0.5 g of sawdust was added, and mixed occasionally. The color and color

intensity were recorded. • Time stopped when the sample turned color. • The time, color, and color intensity were recorded. The color and color intensity of the samples were recorded after 1 hour, 2 hours, and 1 day. DATA

Figure A-19: Color of Sample Blank

Wood Type Untreated CC CDDC CBA ACQ Borate CCA

Trial 1 clear beige dk yellow-orange

yellow-orange

yellow-orange

white-clear clear

Trial 2 clear beige dk yellow-orange

yellow-orange

yellow-orange

white-clear clear

Table A-7: Color Description of Samples, Initial

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Trial 1

Trial 2

Table A-8: Pictures of Samples, Initial


Trial 1 -- -- -- -- -- --

Trial 2 -- -- -- -- -- --

NOTE: Pictures not shown in above table are samples that did not change color within 2 hours.

Table A-9: Pictures of Samples, Stop Time

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Trial 1

Trial 2

Table A-10: Pictures of Samples, 1 Hour


Trial 1 clear (>2h)

dk beige (>2h)

dk yellow-orange (>2h)

yellow-orange (>2h)

yellow-orange (>2h)

white-clear (>2h)

med blue (11m 52s)

Trial 2 clear (>2h)

dk beige (>2h)

dk yellow-orange (>2h)

yellow-orange (>2h)

yellow-orange (>2h)

white-clear (>2h)

med blue (9m 23s)



Trial 1

Trial 2

Table A-12: Pictures of Samples, 2 Hours

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Trial 1

Trial 2

Table A-13: Pictures of Samples, 1 Day

CONCLUSION This experiment showed that the stannous chloride method did not react with alternative treated woods; therefore, it can be used to establish if wood has been treated with CCA. This experiment may be improved by using shredded wood because sawdust may not contain as much arsenate as shredded wood. This will explain for the decreased color intensity for the CCA sawdust than in the CCA shredded wood, as determined from a previous experiment (“Testing Shredded Wood Samples in Solution”). Because sawdust is much finer than the shredded wood, it is more likely to be suspended in the solution, which influences the appearance of the solution.

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Comparing Ammonium Molybdate to Stannous Chloride Ratios in Solutions of Shredded Wood

DATES OF EXPERIMENT: June 22, 2004 to June 24, 2004 PURPOSE This experiment was performed to determine the possibility of straying from the advised phosphate detection method described in Standard Methods to develop the ideal ratio for detecting arsenate. Standard Methods advises an 8:1 ratio of ammonium molybdate to stannous chloride. Other factors considered in this experiment were the reaction time it takes to turn color and the color intensity before and after the reaction. ADDITIONAL REAGENTS • Combined ammonium molybdate and stannous chloride reagent

o NOTE: Stannous chloride reagent was very viscous and difficult to measure out exactly. The following reagents resulted in approximately 20 mL of each reagent. This volume was chosen for convenience of measuring and mixing; however, less than 1 mL will be used.

o 1 to 1: 10 mL stannous chloride reagent was added to 10 mL ammonium molybdate reagent.



o 12 to 1: 1.5 mL stannous chloride reagent was added to 18 mL ammonium molybdate reagent.

o 16 to 1: 1.25 mL stannous chloride reagent was added to 20 mL ammonium molybdate reagent.

PROCEDURE Five groups of samples were tested: 1 to 1, 4 to 1, 8 to 1, 12 to 1, and 16 to 1. A blank was prepared for each group consisting of 10 mL of distilled water and 9 drops of reagent at a specific ratio. The color and color intensity of each blank were recorded. Each group tested phosphate and shredded wood samples in the following order: Phosphate, Untreated Wood, 4.0 kg/m3 CCA-Treated Wood, 9.6 kg/m3 CCA-Treated Wood, 40 kg/m3 CCA-Treated Wood, and Weathered Wood. The following procedure was used for each of the phosphate samples: • Time started once 9 drops of reagent at a specific ratio were added to 10 mL of phosphate,

and mixed occasionally. • Time stopped when the sample turned color. • The time, color, and color intensity were recorded. The following procedure was used for each of the shredded wood samples tested with its respective ratio of ammonium molybdate to stannous chloride. • To 10 mL of distilled water, 9 drops of reagent were added at a specific ratio, and mixed. • Time started once 0.5 g of shredded wood was added, and mixed occasionally. The color

and color intensity were recorded.

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• Time stopped when the sample turned color. • The time, color, and color intensity were recorded. The color and color intensity of the samples were recorded after 2 hours, 5 hours, and 1 day. DATA

1 to 1 4 to 1 8 to 1 12 to 1 16 to 1

Table A-14: Pictures of Reagents with Different Ratios (Ammonium Molybdate to Stannous

Chloride)

Ratio (AmMo to SnCl2)

Color

1 to 1 pale orange 4 to 1 pale orange 8 to 1 faint yellow tint 12 to 1 faint yellow tint 16 to 1 faint yellow tint

Table A-15: Color Description of Blanks

1 to 1 4 to 1 8 to 1 12 to 1 16 to 1

Table A-16: Pictures of Blanks with Different Ratios (Ammonium Molybdate to Stannous

Chloride)

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Shredded Wood Samples Ratio (AmMo

to SnCl2) Phosphate

Untreated 4.0 kg/m3 CCA

9.6 kg/m3 CCA


1 to 1

4 to 1

8 to 1

12 to 1

16 to 1

Table A-17: Pictures of Samples at Start Time

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to SnCl2) Phosphate


9.6 kg/m3 CCA


1 to 1 -- -- -- --

--

4 to 1 -- --

8 to 1

--

12 to 1

16 to 1

NOTE: Pictures not shown in above table are samples that did not change color within 2 hours.

Table A-18: Pictures of Samples at Stop Time

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to SnCl2) Phosphate


9.6 kg/m3 CCA


1 to 1

opaque pale yellow-orange (>2h)

opaque pale white-gray

(>2h)

opaque pale orange-gray

(>2h)

opaque pale gray-blue

(>2h)

opaque blue (>2h)

opaque pale orange-

white (>2h)

4 to 1 opaque white (>2h)

opaque orange-white (>2h)

opaque blue-gray (21m 52s)

opaque blue (9m 40s)

opaque intense blue

(6m 40s)

opaque med blue to blue (19m 55s)

8 to 1 blue-green (21m)

faint yellow tint

(47m)

med blue (10m)

blue (7m)

intense blue (4m 30s)

blue (10m 20s)

12 to 1 lt blue-green (20m)

faint gray tint

(32m)

lt to med blue

(13m)

med blue (8m)

intense blue (5m)

med blue (15m 30s)

16 to 1 lt blue-green (21m)

gray tint (22m 30s)

lt blue (14m)

med blue (8m 30s)

blue (6m)

lt blue (13m)


Figure A-20: Picture of 8 to 1 Shredded Wood Samples achieved in “Testing Shredded Wood

Samples in Solution”

4.0 kg/m3 CCA 9.6 kg/m3 CCA 40 kg/m3 CCA Weathered Untreated

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to SnCl2) Phosphate

Untreated 4.0 kg/m3 9.6 kg/m3 40 kg/m3 Weathered

1 to 1

4 to 1

8 to 1

-- -- -- -- --

12 to 1

NOTE: Pictures of shredded wood samples with an 8 to 1 ratio is not shown because it was performed in a previous experiment (“Testing Shredded Wood Samples in Solution”); see Figure 1. Pictures of phosphate and shredded wood samples with a 16 to 1 ratio is not shown because the color and intensity was very similar to that achieved with the 12 to 1 ratio.

Table A-20: Pictures of Samples After 5 Hours

Ratio (AmMo to SnCl2)

Time Difference

1 to 1 - 4 to 1 >1h 38m 8s 8 to 1 37m 12 to 1 19m 16 to 1 8m 30s

Table A-21: Time Difference between Untreated and 4.0 kg/m3 CCA-Treated Wood Samples

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to SnCl2) Phosphate

Untreated 4.0 kg/m3 9.6 kg/m3 40 kg/m3 Weathered

1 to 1

4 to 1

8 to 1

12 to 1

NOTE: Pictures of phosphate and shredded wood samples with a 16 to 1 ratio is not shown because the color and intensity was very similar to that achieved with the 12 to 1 ratio.

Table A-22: Pictures of Samples After 1 Day CONCLUSION Deviating from the Standard Methods advised ammonium molybdate to stannous chloride ratio of 8 to 1 did not exhibit a better color, color intensity, or reaction time, but only the ratios of 1 to 1, 4 to 1, 8 to 1, 12 to 1, and 16 to 1 were tested. Further experimentation into the possibility of finding a better ratio to detect arsenate would center around 8 to 1, but in smaller increments, such as 6 to 1, 7 to 1, 8 to 1, 9 to 1, and 10 to 1. However, this researcher feels that doing that experiment would not be important unless a final product is developed and refining the method is necessary. In this experiment, the 8 to 1 ratio was best because it had the largest difference in reaction time between the untreated and 4.0 kg/m3 CCA-treated wood samples. In addition, the

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color and color intensity achieved by the 8 to 1 ratio was easier to determine between the untreated and 4.0 kg/m3 CCA-treated wood samples. As the amount of stannous chloride added became more equal to the amount of ammonium molybdate, the solution became more opaque, most likely due to the increased concentration of metal in the solution. Also, the reaction time was longer. As the amount of ammonium molybdate increased over the amount of stannous chloride present, the reaction time for the CCA-treated wood samples became slightly higher, but the reaction time for the untreated wood sample became lower. Thus, it reduced the time difference between the appearance of a color change of untreated and 4.0 kg/m3 CCA-treated wood. The color intensity of the solutions also decreased.

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Stannous Chloride Stain Mixing Time #1 DATE OF EXPERIMENT: December 22, 2004 PURPOSE This experiment was intended to determine the time frame for the ammonium molybdate and stannous chloride reagents to be allowed to react with each other before being added to the sample in order to create an ideal reaction time and color intensity when using the dissolution method. PROCEDURE • The ammonium molybdate and stannous chloride reagents were combined in an 8 to 1 ratio.

It was mixed and then let stand. The combined reagent was immediately tested using the dissolution method for untreated and 4.0 kg/m3 CCA-treated wood; this was mixing time 0.

• The combined reagent was tested every minute for 10 minutes using the dissolution method for untreated and CCA-treated wood.

• The reaction time started when the wood was added to the solution. • The stop time was noted for all samples.

o The stop time was defined as the time the sample solution begins to change color. DATA

Mixing Time (min) 0 1 2 3 4 5 6 7 8 9 10 Untreated 00:10 02:11 26:00 -- -- -- -- -- -- -- --

4.0 kg/m3 CCA 00:15 02:43 10:58 12:40 11:50* 11:37 11:36 11:42 11:40 11:40 11:35NOTE: mm:ss *Some CCA-treated wood sample for mixing time 4 minutes spilled.

Table A-23: Sample Reaction Time CONCLUSION This experiment somewhat confirmed the suspicions that formulated following the attempted shelf life test (November 16, 2004 to December 20, 2004). The untreated wood continued to react (express a positive result) for the initial mixing time samples (0, 1, and 2 minutes). This was most likely caused by the time required for the Sn2+ to reduce enough molybdenum to make the combined stain not sensitive to phosphate, thus, specific to arsenate. After mixing time 3 minutes, only CCA-treated wood continued to react and the reaction time was more consistent. For mixing time samples 4 to 10 minutes, the range in reaction time was 11:35 to 11:50; mode, median, and average reaction time was 11:40. Future experiments should focus on exactly what mixing time gives the best results, and the mixing time at which the combined stain does not give a reasonable reaction time any further should be determined. Although the reaction time is stopped when a noticeable blue color develops in the sample, the time required for the CCA-treated wood sample to achieve maximum color intensity should be also be determined.

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Stannous Chloride Stain Mixing Time #2 DATE OF EXPERIMENT: December 24, 2004 PURPOSE This experiment was intended to focus on the mixing time frame of 3 to 9 minutes to create an ideal reaction time and color intensity when using the dissolution method. An attempt to determine the time at which the combined stain fails to continue to give a reasonable reaction time (approximately 15 minutes) will also be performed. PROCEDURE • The ammonium molybdate and stannous chloride reagents were combined in an 8 to 1 ratio,

mixed, and let stand. • The combined reagent was tested using the dissolution method for untreated and 4.0 kg/m3

CCA-treated wood every minute for mixing time 3 to 9 minutes. • The combined reagent was tested at mixing time 30 and 45 minutes. • The reaction time started when the wood was added to the solution. • The stop time was noted for all samples.

o The stop time was defined as the time the sample solution begins to change color. • The samples were monitored every hour until the color intensity reached a maximum and

started to decrease. Any changes in color or color intensity were noted. DATA

Mixing Time (min) 3 4 5 6 7 8 9 30 45 Untreated 40:30 -- -- -- -- -- -- -- --

4.0 kg/m3 CCA 11:41 11:09 11:19 10:55 09:34 10:52 10:52 12:09 12:59NOTE: mm:ss

Table A-24: Sample Reaction Time

Time (hr) 1 2 3 4 5 6

Untreated All: nc All: nc All: nc All: nc All: nc All: nc

4.0 kg/m3 CCA All: color intensity

increasing

All: color intensity

increasing


increasing


increasing


similar to 4 hr

3, 6, & 7 min: color intensity decreasing; 4, 5, 8, 9, 30, & 45 min: color intensity similar to 4 & 5 hr

NOTE: nc = no change; When referring to time of samples in minutes, it means the mixing time at which the samples were tested. When referring to the time in hours, it means since the beginning of reaction time (the time at which wood was added to the solution).

Table A-25: Description of Color Intensity of Samples CONCLUSION The data from Table A-24 express that having a mixing time of 7 minutes gives the best result although not much of a difference from the ±2 minute mixing times; however, the mixing time of 45 minutes still maintained a reasonable reaction time (less than 15 minutes). In this

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experiment, it should be noted that although the samples began to change color at the reaction times indicated in Table A-24, the time at which the samples were obviously blue occurred around 20 minutes. By monitoring the samples, the maximum color intensity was determined to occur around 4 hours after addition of wood to the solution. It would be beneficial to perform this experiment again to confirm the results, but not necessary.

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Long-Term Stannous Chloride Stain Ratios DATE OF EXPERIMENT: May 16, 2005 and May 19, 2005 PURPOSE This experiment was performed in efforts to continue with the possibility of developing a long-term combined stannous chloride stain that already mixed the ammonium molybdate and stannous chloride reagents. Currently, the design for the most effective stain involves keeping both reagents separated until right before testing and then having an additional waiting time of five minutes before actually testing the sample. By designing a long-term combined stain, it will eliminate the need for excess test preparation steps. The typical ratio of 8 parts ammonium molybdate reagent to 1 part stannous chloride reagent will only be increased because the previous attempt to change the stains composition for long-term storage led to the determination that only by adding more ammonium molybdate reagent could the stain remain effective. PROCEDURE • Six combined stains of differing ratios of ammonium molybdate and stannous chloride

reagents were prepared, as defined in Table A-26 below.

Stain Parts Ammonium Molybdate

Part Stannous Chloride

A 8 1 B 16 1 C 32 1 D 64 1 E 128 1 F 256 1

*G 4 1 *H 2 1

*Samples G and H were created on May 19, 2005

Table A-26: Composition of Long-Term Stannous Chloride Stains • Stains A through H were mixed for 24 hours. • 10 mL distilled water were added to a 20-mL sample vial; a total of 12 sample vials were

prepared. • 9 drops of each Stain (A through H) were added into the sample vials; two vials per stain. • 0.5 g of untreated or 4.0 kg/m3 CCA-treated wood was added into the sample vials; each

Stain (A through H) had one vial with untreated wood and one vial with CCA-treated wood. • The stop time, noticeable time, and approximate time of maximum intensity were noted.

o The stop time was defined as the time the sample solution begins to change color, or when a faint to light blue color appeared

o The noticeable time was defined as the time the color of the sample solution appeared light to medium blue.

o The approximate time of maximum intensity was defined as the time the color intensity reached a maximum and started to decrease.

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DATA

Time Stain Type of Wood Stop Noticeable Untreated nc nc A 4.0 kg/m3 CCA 00:11:26 00:48:32 Untreated nc nc B 4.0 kg/m3 CCA 00:09:34 00:46:20 Untreated nc nc C 4.0 kg/m3 CCA 00:22:36 00:57:08 Untreated nc nc D 4.0 kg/m3 CCA 00:43:42 nc Untreated nc nc E 4.0 kg/m3 CCA 03:13:36 nc Untreated nc nc F 4.0 kg/m3 CCA nc nc Untreated nc nc G 4.0 kg/m3 CCA nc nc Untreated nc nc H 4.0 kg/m3 CCA nc nc

NOTE: hh:mm:ss nc = no change

Table A-27: Reaction Time of Stain Ratios Approximate time of maximum color intensity: 4 hours (only Stain A, 4.0 kg/m3 CCA-treated

wood reached an intense blue color) CONCLUSION This experiment did not provide a better ratio of ammonium molybdate to stannous chloride reagents for the stain. Higher ratios of ammonium molybdate to stannous chloride did not result in a shorter reaction time, except for Stain B. However, Stain B did not yield an intense blue color, which is highly undesirable. DISCUSSION The stain seems to be highly sensitive to many variables, which may or may not be able to be corrected for. Possibly concentrating the different ratios of ammonium molybdate to stannous chloride around 8 to 1, such as reproducing the same experiment for 6 to 1, 7 to 1, 9 to 1, 10 to 1, and 11 to 1. In addition, the effects of pH need to be researched.

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Periodic Shaking of the Sample DATE OF EXPERIMENT: May 18, 2005 PURPOSE This experiment was intended to determine if shaking the sample vial periodically is actually necessary when testing a wood sample with the stannous chloride stain dissolution method. In consideration of the other preparation steps required to test a sample, it would be best to reduce any trivial steps. PROCEDURE • The dissolution method was performed using the stannous chloride stain on untreated and 4.0

kg/m3 CCA-treated wood. • Upon addition of the wood, an initial shake was performed to all samples. • One untreated and one CCA-treated sample was periodically shaken for the duration of the

test; the other untreated and CCA-treated samples was let stand for the duration of the test. • The stop time, noticeable time, and approximate time of maximum intensity were noted.




DATA

Time Sample Type of Wood Stop Noticeable Untreated nc nc Shaken Periodically 4.0 kg/m3 CCA 08:03 24:50 Untreated nc nc Not Shaken 4.0 kg/m3 CCA 15:50 27:00

NOTE: mm:ss nc = no change Table A-28: Reaction Time of Shaking and Non-Shaking

Approximate time of maximum intensity: 4 hours (the color of the unshaken sample was a

lighter blue color than the shaken sample, but still intense) CONCLUSION This experiment concluded that there was no necessity to shake the sample because there was no appreciable difference in reaction times. The stannous chloride stain dissolution method was able to develop a blue color with a similar reaction time and an intense blue color whether the sample vial was periodically shaken or not. A deeper blue typically developed in 4.0 kg/m3 CCA-treated wood when the sample was periodically shaken.

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Whirl-Pak Bags with the Stannous Chloride Stain DATE OF EXPERIMENT: March 9, 2005 PURPOSE This experiment was intended to determine if Whirl-Pak bags may be used as the container for the stannous chloride stain dissolution method instead of the 20-mL sample vials (scintillation vials). Whirl-Pak bags would be cheaper than the scintillation vials; however, this would most likely be advised only when testing a large number of samples. PROCEDURE • 1.25 g sample sawdust/shredded wood (Untreated; 4.0 kg/m3 CCA) were added to a 2 oz. (60

mL) Whirl-Pak bag. • 25 mL distilled water were added to the Whirl-Pak bag • 25 drops of the stannous chloride stain were added to the Whirl-Pak bag.

o NOTE: The stannous chloride stain was created using the same method by adding 8 parts ammonium molybdate reagent to 1 part stannous chloride reagent; mixed and let stand for 5 minutes.

• The reaction time (Stop and Noticeable Time), color, and color intensity of the Whirl-Pak bag samples were noted. o The stop time was defined as the time the sample solution begins to change color, or

when a faint to light blue color appeared o The noticeable time was defined as the time the color of the sample solution appeared

light to medium blue. o The approximate time of maximum intensity was defined as the time the color intensity

reached a maximum and started to decrease. DATA

Type of Wood Stop Time Noticeable Time

Untreated nc nc

4.0 kg/m3 CCA 12:50 16:20 light blue

NOTE: mm:ss nc = no change

Table A-29: Reaction Time, Color, and Color Intensity of Whirl-Pak Bag Samples Approximate time of maximum intensity: 5 hours

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Figure A-21: Picture of Whirl-Pak Bag Samples, 24 hours, Untreated (right) and 4.0 kg/m3

CCA-Treated Wood (left) CONCLUSION The stannous chloride stain dissolution method continued to be effective whether the sample container is a glass scintillation vial or a Whirl-Pak bag. The reaction time and color intensity for the wood sample in the Whirl-Pak bag was so similar to the scintillation vial that the usage of Whirl-Pak bags is a viable option to reduce the overall cost of supplies when testing a large number of samples.

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Testing the Diluted Combined Stannous Chloride and Ammonium Molybdate Stain on Various Treated Woods

DATE OF EXPERIMENT: August 12, 2004 PURPOSE This experiment was performed to determine the possibility of testing wood samples for arsenic by applying a diluted combined reagent of ammonium molybdate and stannous chloride to its surface. Other factors considered in this experiment were the reaction time it takes to turn color and color intensity. ADDITIONAL REAGENTS • Combined ammonium molybdate and stannous chloride reagent

o 1 mL stannous chloride reagent was added to 8 mL ammonium molybdate reagent, and mixed.

o NOTE: The stannous chloride reagent was very viscous and difficult to measure out exactly 1 mL; therefore, it was easier to add the stannous chloride reagent dropwise. Must maintain the 8:1 ratio of ammonium molybdate to stannous chloride.

• Combined ammonium molybdate and stannous chloride reagent with distilled water o Solution 1 (2 to 1)

10 mL combined ammonium molybdate and stannous chloride reagent were added to 5 mL distilled water, and mixed.

o Solution 2 (1 to 1) 7.5 mL combined ammonium molybdate and stannous chloride reagent were added to

7.5 mL distilled water, and mixed. o Solution 3 (1 to 2)

5 mL combined ammonium molybdate and stannous chloride reagent were added to 10 mL distilled water, and mixed.

PROCEDURE There were three groups that were used in this experiment, each based on the different diluted stain, or solution, that was applied. Each group consisted of a sample of whole wood of Untreated, CC, CDDC, CBA, ACQ, Borate, and 4.0 kg/m3 CCA-Treated Wood. Drops of the diluted stain were applied on the tangential face between the rings. Any contact with the wood samples on stain application site when handling was reduced as much as possible. • Solution 1 (2 to 1)

o Time started once random drops of combined ammonium molybdate and stannous chloride reagent were placed on the surface of the wood. Three to four drops per two square inches were placed between the rings.

o The time that the first drop is absorbed into the wood was recorded. o Time stopped once a bluish color change occurred. o The stop time, color, and color intensity were recorded.

The stop time was defined as the time the sample solution begins to change color, or when a faint to light blue color appeared.

• Solution 2 (1 to 1)

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o Time started once random drops of combined ammonium molybdate and stannous chloride reagent were placed on the surface of the wood. Three to four drops per two square inches were placed between the rings.

o The time that the first drop was absorbed into the wood was recorded o Time stopped once a bluish color change occurred. o The stop time, color, and color intensity were recorded.


• Solution 3 (1 to 2) o Time started once random drops of combined ammonium molybdate and stannous

chloride reagent were placed on the surface of the wood. Three to four drops per two square inches were placed between the rings.

o The time that the first drop was absorbed into the wood was recorded. o Time stopped once a bluish color change occurred. o The stop time, color, and color intensity were recorded.


The color and color intensity were recorded after 24 hours. DATA

Solution Untreated CC CDDC CBA ACQ Borate CCA

1

2

3

Table A-30: Pictures of Wood Samples, Initial

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Solution 1 Solution 2 Solution 3

Table A-31: Pictures of Combined Ammonium Molybdate and Stannous Chloride Reagent with

Water Solution Untreated CC CDDC CBA ACQ Borate CCA

1 brown-gray brown brown brown brown brown-gray intense blue (22m 8s)

2 brown-gray brown brown brown brown brown-gray intense to med

blue (18m 47s)

3 brown-gray brown brown brown brown brown-gray med blue (unable to tell)



1

2

3

Table A-33: Pictures of Wood Samples, 2 Hours

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1 gray brown brown brown brown gray intense blue

2 gray brown brown brown brown gray intense blue

3 gray brown brown brown brown gray intense to med blue

Table A-34: Color and Color Intensity, 24 Hours


1

2

3

Table A-35: Pictures of Wood Samples, 24 Hours CONCLUSION In this experiment, it was shown that diluting the combined ammonium molybdate and stannous chloride reagent did work in hard wood application. Because the color of the stain was changed prior to application, there was no confusion between Untreated, Borate, and CCA-Treated Wood. The blue color was strongest in Solution 1 where the combined ammonium molybdate and stannous chloride reagent to distilled water ratio is 2 to 1. As expected, the blue color got lighter as the stain became more diluted. Therefore, to find the most intense blue color, it was necessary to find the minimum amount of distilled water that may be added to the stain, but enough so the stain itself turned a yellow color. This experiment also had a problem with the reaction time being around 20 minutes. The reaction time may be decreased by performing the experiment in sunlight to increase the drying time of the wood.

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Testing Whole Wood Application Methods of the Combined Stannous Chloride and Ammonium Molybdate Stain on Various Treated Woods

DATE OF EXPERIMENT: August 11, 2004 PURPOSE This experiment was performed to determine the possibility of testing wood samples for arsenic by applying a combined reagent of ammonium molybdate and stannous chloride to its surface. Other factors considered in this experiment were the reaction time it takes to turn color, color intensity, application method, and application surface. PROCEDURE There were six groups that were used in this experiment based on different stain application methods. Each group consisted of a sample of whole wood samples of Untreated, CC, CDDC, CBA, ACQ, Borate, and 4.0 kg/m3 CCA-Treated Wood. The stain was applied on the radial or tangential face for group 1 and on the transverse face for group 2. For each application surface, the stain was applied to the wood surface on both the rings and the softwood. When handling the wood samples, any contact with stain application site was reduced as much as possible. • Drop 1 & 2

o Time started once random drops of combined ammonium molybdate and stannous chloride reagent were placed on the surface of the wood. Three to four drops per two square inches.

o The time that the first drop was absorbed into the wood was recorded. o Time stopped once a bluish color change occurred. o The stop time, color, and color intensity were recorded.

The stop time was defined as the time the sample solution begins to change color, or when a faint to light blue color appeared

• Swipe 1 & 2 o A Kimwipe was moistened with the combined ammonium molybdate and stannous

chloride reagent. o Time started once the wood surface was swiped with the moistened Kimwipe. The

surface may have to have been swiped more than once. o A new Kimwipe was used for each wood sample to avoid cross contamination. o Time stopped once a bluish color change occurred. o The stop time, color, and color intensity were recorded.

The stop time was defined as the time the sample solution begins to change color, or when a faint to light blue color appeared

• Drop-Sit-Swipe 1 & 2 o Time started once random drops of combined ammonium molybdate and stannous

chloride reagent were placed on the surface of the wood. Three to four drops per two square inches.

o After five minutes, the wood surface was swiped with a Kimwipe. o A new Kimwipe was used for each wood sample to avoid cross contamination. o Time stopped once a bluish color change occurred. o The stop time, color, and color intensity were recorded.

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The color and color intensity were recorded after 12 hours. DATA

Application Method Untreated CC CDDC CBA ACQ Borate CCA

Drop 1

Drop 2

Swipe 1

Swipe 2

Drop-Sit-Swipe 1

Drop-Sit-Swipe 2

Table A-36: Pictures of Samples, Initial

Figure A-22: Picture of Combined Ammonium Molybdate and Stannous Chloride Reagent

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Drop 1 4m 41s 3m 39s 7m 31s 3m 55s 3m 44s 43s 3m 4s

Drop 2 1m 5s 1m 12s 1m 45s 1m 25s 1m 37s 34s 1m 52s

Table A-37: Absorption Times


Drop 1 brown-gray brown brown brown brown brown-gray gray-blue (>1h 30m)

Drop 2 brown-gray brown brown brown brown brown-gray gray-blue (>1h 30m)

Swipe 1 brown-gray brown *unable to tell brown brown brown-gray gray-blue

(>1h) Swipe 2 brown-gray brown brown brown brown brown-gray gray Drop-Sit-Swipe 1 brown-gray brown *unable

to tell brown blue (>1h 30m) brown-gray intense blue

(19m 44s) Drop-Sit-Swipe 2 brown-gray brown brown brown brown brown-gray gray-blue

(>1h 30m) *Some CDDC-Treated Wood samples were “unable to tell” because of the already dark color of the wood.



Drop 1

Drop 2

Swipe 1

Swipe 2

Drop-Sit-Swipe 1

Drop-Sit-Swipe 2

Table A-39: Pictures of Samples,1 Hour 30 Minutes

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Drop 1 gray brown brown brown brown gray lt blue

Drop 2 brown-gray brown brown brown brown gray lt blue

Swipe 1 brown-gray brown *unable to tell brown brown brown-gray lt blue

Swipe 2 brown-gray brown brown brown brown brown-gray gray Drop-Sit-Swipe 1 gray brown *unable

to tell brown blue gray intense blue

Drop-Sit-Swipe 2 brown-gray brown brown brown brown brown-gray med blue

*Some CDDC-Treated Wood samples were “unable to tell” because of the already dark color of the wood. Table A-40: Color and Color Intensity of Samples, 12 Hours

Application

Method Untreated CC CDDC CBA ACQ Borate CCA

Drop 1

Drop 2

Swipe 1

Swipe 2

Drop-Sit-Swipe 1

Drop-Sit-Swipe 2

Table A-41: Pictures of Samples, 12 Hours

CONCLUSION In this experiment, it was shown that the combined ammonium molybdate and stannous chloride reagent did work in whole wood application to varying degrees. The best result was the CCA-Treated Wood Drop-Sit-Swipe 1 sample with a reaction time of 19 minutes 44 seconds. This was approximately 10 minutes over the reaction time achieved with the shredded wood samples in solution. Because better results were achieved in group 1 than in group 2, this researcher discovered that the radial or tangential wood surface was the best surface for the

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combined ammonium molybdate and stannous chloride stain application. The tangential surface was seemingly the best surface to apply this stain because of the greater surface area to apply the stain and the increased availability of arsenate to react with the stain. This combined ammonium molybdate and stannous chloride stain appeared to react better on softwood (spaces between the rings) than on the rings of the wood, unlike the ascorbic acid method. However, the results were somewhat misleading. Because the initial reagent was already a dark blue color, certain wood types (Untreated, Borate, and CCA-Treated Wood) all looked alike in color for the first 10 to 13 minutes after stain application. Gradually, CCA-Treated Wood began to distinguish itself from the other types of wood by becoming more blue in color, but an untrained eye may not be able to see the difference. Because of this, it is evident that more experimentation is needed to either change the color of the reagent, decrease the time needed for the blue color to appear, or increase the blue color intensity. In addition, the ACQ-Treated Wood Drop-Sit-Swipe 1 sample reacted blue. The reason why is not known. Fortunately, no other ACQ-Treated Wood samples tested positive. Yet, further experimentation into ACQ-Treated Wood may be necessary to determine if the positive result seen in this experiment is a true or false positive. For the best results in applying the combined stannous chloride and ammonium molybdate stain, should not be applied onto wood surfaces where the wood is very compact, such as the hardness found in heartwood. The application surface should also have the most chemical treatment, determined by the discoloration from the natural wood color. The amount of stain applied to the surface should not be too great because the color seems to appear slower because it is difficult to see the difference between when the wood is wet and when the reaction is giving off the color. Further experimentation should look into possibly increasing the drying rate of the stain onto the surface. Carrying out the experiment in sunlight may aid in seeing the blue color quicker.

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Spray Application of the Diluted Combined Stannous Chloride and Ammonium Molybdate Stain on Wood

DATE OF EXPERIMENT: August 25, 2004 PURPOSE This experiment was performed to evaluate the possibility of testing wood samples for arsenic by applying a diluted combined reagent of ammonium molybdate and stannous chloride to its surface using a spray application method. Other factors considered in this experiment were the reaction time it takes to turn color and color intensity. PROCEDURE Two trials were performed testing Untreated and CCA-Treated Wood. The diluted stain was applied on the tangential face as evenly as possible. However, half of the whole wood sample was covered to serve as a color change comparison. When handling the wood samples, any contact with stain application site was reduced as much as possible. • Time started once the whole wood sample was sprayed with the diluted combined

ammonium molybdate and stannous chloride reagent. • Time stopped once a bluish color change occurred. • The stop time, color, and color intensity were recorded.

o The stop time was defined as the time the sample solution begins to change color, or when a faint to light blue color appeared.

DATA

Trial Untreated CCA

1

2

Table A-42: Pictures of Wood Samples, Initial

Trial Untreated CCA

1 lt brown dk brown-blue (30m)

2 lt brown blue (22m) Table A-43: Color, Color Intensity, and Time of Sample Reactions

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Trial Untreated CCA

1

2

Table A-44: Pictures of Wood Samples, 25 Minutes

Trial Untreated CCA

1

2

Table A-45: Pictures of Wood Samples, 2 Hours

CONCLUSION This experiment was somewhat successful. The spray application did work in detecting CCA-Treated wood with a reaction time similar to that seen in previous experiments on hard wood. Unfortunately, the CCA-Treated Trial 1 wood sample contained compact wood because of heartwood; therefore, results were not optimal. Additionally, the blue color that formed was scattered and more difficult to witness a definite color change. This was due to the reduced amount of reagent that was absorbed into the wood to react with arsenate. However, the drying of the wood was not a problem. Therefore, it seems that the ideal method of stain application would have to apply enough reagent to be absorbed into the wood, but not so much as to make the wood wet. Spraying the wood heavily with the reagent, allowing it to sit, and then wiping off excess reagent could be a possibility. Another possible application method would be to use a paintbrush to apply the stain on the wood, which should have a heavy layer of reagent. Note that by applying more reagent onto the wood surface would result in a similar drop application method.

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Stannous Chloride Stain – Whole Wood Application in Sunlight DATE OF EXPERIMENT: September 10, 2004 PURPOSE This experiment is intended to determine the effectiveness of the stannous chloride stain applied to whole wood in intense sunlight. Sunlight will also reduce the drying time of the stain, which may allow the blue color to appear quicker. PROCEDURE • Whole Wood Application Method

o Diluted combined stannous chloride stain o Untreated, Borate, ACQ, CBA, CC, CDDC, 4.0 kg/m3 CCA-treated wood samples

DATA • Location of Experiment

o Behind University of Miami, FL, McArthur Engineering Building o Temperature: 28.1°C (82.6°F) to 29.4°C (84.9°F) o Humidity: 23.2% to 24.0% o Time of Experiment: 1:40pm to 3:40pm EST o Weather Description: intense sun; hot; somewhat humid; some clouds, but not overhead

Figure A-23: Picture of Location of Experiment

Figure A-24: Pictures of Weather Conditions during Experiment

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Untreated Borate ACQ CBA CC CDDC CCA 6m -- -- -- -- -- 2m 30s

*Stop time when blue color first observed.

Table A-46: Sample Reaction Times

Time (min) Untreated Borate ACQ CBA CC CDDC CCA

2.5 -- -- -- -- -- -- intense blue

6 lt. blue-green lt. gray -- brown brown Dk. brown dk. blue

11 intense blue-green gray -- brown brown dk. brown dk. brown

30 dk. brown dk. brown -- dk. brown dk. brown black black

60 black dk. brown -- dk. brown dk. brown black black

120 black black -- dk. brown black black black

Table A-47: Color and Color Intensity of Whole Wood Samples in Sunlight

Time (min) Untreated Borate ACQ CBA CC CDDC CCA

0

2.5 -- -- -- -- -- --

6

--

11

-- -- -- -- -- --

30

60

120

Table A-48: Pictures of Whole Wood Samples in Sunlight

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CONCLUSION This experiment showed that exposure to sunlight does decrease the reaction time; however, the stain still reacts with untreated wood and it does not remain blue. Over time, the stain turns brown or black regardless of the type of wood. CCA-treated wood reacts 3 minutes 30 seconds faster than untreated wood, but this time difference is insufficient to be able to properly determine the difference between untreated and CCA-treated wood. Therefore, it is not advised that the diluted stannous chloride stain be used on whole wood in direct sunlight.

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APPENDIX B

Laboratory Reports for the Field Test, Minimum Detection Limit, and Shelf-Life of the Stannous Chloride Stain

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Stannous Chloride Stain Dissolution Method Field Test #1 DATE OF EXPERIMENT: June 5, 2005 PURPOSE This test was intended to determine the actual effectiveness of the stannous chloride stain dissolution method. If the stain failed to identify used CCA-treated wood from used untreated or alternative treated wood, then it is unlikely that the stain should even be marketed. The sample pieces of wood were obtained from Florida Wood Recycling facility in Medley, Florida. The sample pieces of wood collected were already tested using a PAN indicator stain and an XRF unit. Table B-1 is a summary of the results achieved from testing the samples with PAN indicator and the XRF unit. The samples were brought back to a laboratory where they were subsequently drilled and the shavings for each wood sample were collected into individual Ziploc bags.

Result Elements Detected by XRF Unit

(Average, ppm) Sample PAN Indicator (+/–)

Cr Cu As

Determined Chemical Treatment Preservative

A – <216.3 174.7 <10 *Borate B – <205.3 <35.7 <9.3 *Borate C + <284 <34 <10.3 Untreated D + <241.7 <51.3 <11.7 Untreated E + <261.3 10248 <9.7 Copper F + <253.3 1481 <18 Copper G + <236 6013 <10 †ACQ H + 9194.3 5412.3 6431.7 CCA I + 2526.3 1418.7 1476.3 CCA

NOTE: XRF values were taken from an average of three trials for each sample. *Borate treated wood was determined due to the very green color of wood, which is most likely a dye added in many borate treatment processes to specify that the wood is treated with a chemical preservative. †An identifying tag was still attached to Sample G indicating it was ACQ-treated wood.

Table B-1: Sample Results from PAN Indicator and XRF Analysis PROCEDURE • The shavings from each sample wood were tested using the stannous chloride stain

dissolution method. • The stop time, noticeable time, and approximate time of maximum intensity were noted.




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DATA

Time Sample Stop Noticeable A nc nc B nc nc C nc nc D nc nc E nc nc F nc nc G nc nc H 15:24 17:24 I 17:42 37:42

NOTE: mm:ss nc = no change

Table B-2: Reaction Time of Stain Field Test Samples Approximate time of maximum intensity: 4 hours (Samples H and I) CONCLUSION This experiment showed that the stannous chloride stain dissolution method was still effective at identifying CCA-treated wood among various samples of used wood. In addition, the stain remains dependent on the concentration of arsenate in the sample. Most of the previous experiments involved in researching the development of an arsenic-specific stain tested CCA-treated wood treated with the smallest typical manufacturer’s concentration of 4.0 kg/m3; therefore, higher concentrations of CCA-treated wood will have a lower reaction time, which was the case in Sample H.

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Stannous Chloride Stain Dissolution Method Field Test #2 DATE OF EXPERIMENT: August 13, 2005 PURPOSE This test was intended to determine the actual effectiveness of the stannous chloride stain dissolution method. If the stain failed to identify used CCA-treated wood from used untreated or alternative treated wood, then it is unlikely that the stain should even be marketed. The sample pieces of wood were obtained from various components of different playground structures located in Miami, Florida. Each sample represented a single piece of wood within the playground structure. Table B-3 shows the locations of the playgrounds from which the samples were collected. The sample pieces of wood collected were already tested with PAN indicator, ascorbic acid, an arsenic test kit, an XRF unit, and an AA spectrometer, but the results were kept hidden from the experimenter to prevent bias. A summary of the results achieved from testing the samples with PAN indicator, ascorbic acid, arsenic test kit, XRF unit, and AA spectrometer are presented in Table B-4 with the results of the stannous chloride stain. It should be noted that PAN indicator is a copper-specific stain and ascorbic acid is not an established method of testing for arsenic-treated wood. The samples were drilled and the shavings for each wood sample were collected into individual Ziploc bags and were subsequently analyzed in the laboratory.

Park Name ADDRESS Date / Time COMMENTS

Amelia Earhart Park

11900 NW 42 Avenue

8/2/2002 5:30pm

White sand buffer material, brown stain on wood, very large park area, disproportional small playground unit, newer and larger plastic playground nearby, old and well worn, few people at time of test but park seems to be well used. Due to wear and older age of playground it can be guessed that outer layer of wood possibly containing arsenic has been eroded and worn out.

Briar Bay Park

SW 128 St and SW 90 Avenue

8/1/2002 11:45am

White sand buffer material, little traffic at time of test (2 adults, 2 children). Upper-middle class neighborhood. Park seems likely to have heavy traffic due to location within a large domestic area, well kept grounds.

Bunche Park 15727 NW 22 Avenue

9/2/2002 12:45pm

Park was wet due to very recent rain-fall; white sand buffer material; low-income neighborhood. Little traffic at time of test, but showed signs of use in past.

Cloverleaf Park

303 NW 191 St

7/31/2002 11:15am

White sand buffer material, not much traffic, no children lower-middle to lower income neighborhood.

Colonial Drive Park

10750 SW 156 Terrace

8/2/2002 2:10pm

White sand buffer material with large area of rubber turf, newer playground, part of a multiple facility park, many children present and involved in different activities throughout park, middle to lower-middle to income neighborhood.

Devonaire Park

10400 SW 122 Avenue

8/1/2002 1:00pm

White sand substrate, heavy use at time of test, multiple children from summer camp, middle-income neighborhood, residential area, part of a multiple facility park.

Francisco Human Rights Park

9445 Coral Way

8/2/02 3:30pm

White sand buffer material, brown wood stain present, older playground unit showing signs of wear, located by a large public library, no traffic at time of test. Due to wear and older age of playground it can be guessed that outer layer of wood possibly containing arsenic has been eroded and worn out.

Table B-3: Location and Description of Sample Collection Playgrounds

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Park Name ADDRESS Date / Time COMMENTS Kendall Indian Hammocks Park

11395 SW 79 St

7/26/2002 9:40am

White sand buffer material, in close proximity to children's camp, highly transited park.

Serena Lake Park

SW 80 St and SW 139 Avenue

9/2/2002 2:45pm

White sand buffer material along with rubber surface (track-like), newer playground. Middle class neighborhood, fair amount of traffic at time of test.

Water Oaks Park

9100 Hammocks Blvd

8/1/2002 2:00pm

White sand buffer material, no traffic at time of test, park behind Hoover Elementary School, middle income, highly residential area.

Table B-3 (con’d): Location and Description of Sample Collection Playgrounds PROCEDURE • The shavings from each sample wood were tested using the stannous chloride stain

dissolution method. • The stop time, noticeable time, and approximate time of maximum intensity were noted.




A-56

DATA

Sample Name PAN

Indicator (+/−)

Ascorbic Acid (+/−)

Arsenic Test Kit

(+/−) XRF Avg.

AA (mg/kg)

AA Avg. Digestate

Conc. (ppm)

Intense Blue with Stannous Chloride Stain

Amelia Earhart 1 + − + 4034.3 3013 30.4 YES Briar Bay Lake 1 + + + 1259.3 521 5.6 YES Briar Bay Lake 2 + + + 1453.1 643 6.5 YES Briar Bay Lake 3 + + + 189.4 159 1.5 NO Bunche 2 + − + 723.8 384 4 YES Bunche1 + − + 4991.8 3229 34.8 YES Clover Leaf 1 + + + 319.7 220 2.2 NO Clover Leaf 2 + + + 2349.6 1224 12.2 YES Clover Leaf 3 + + + 519.2 387 4 YES Colonial Drive 1 + + + 1617.3 1167 13.1 YES Colonial Drive 2 + + + 643.3 742 8.1 YES Colonial Drive 3 + + + 2102.0 1679 18 YES Devonaire 1 + + + 6542.8 4852 47.3 YES Devonaire 2 + + + 2027.7 1498 16.5 YES Devonaire 3 + + + 1768.3 1012 10 YES FHRP 1 + − + 1144.0 652 7 YES FHRP 2 + − + 304.3 149 1.5 NO Indian Hammock 1 + + + 2561.6 1670 18.7 YES Indian Hammock 2 + + + 2549.2 1399 16.4 YES Serena Lakes 1 + + + 1605.2 578 5.8 YES Serena Lakes 2 + − + 3382.9 1795 19.1 YES Serena Lakes 3 + + + 3841.8 2384 25.5 YES Serena Lakes 4 + + + 1161.3 513 5.4 YES Water Oaks 1 + + + 2738.1 1287 13.3 YES NOTE: Sample numbers 1 through 4 indicate the component of the playground from which the sample was collected. (1 = Column; 2 = Floor beam; 3 = Secondary support; 4 = Bridge wood).

Table B-4: Sample Results from PAN Indicator, Ascorbic Acid, Arsenic Test Kit, XRF, AA, and Stannous Chloride Stain Analysis

CONCLUSION This experiment showed that the stannous chloride stain dissolution method was still effective at identifying CCA-treated wood among various samples of used wood. In addition, the stain remains dependent upon the concentration of arsenate in the sample. Samples “FHRP 2,” “Briar Bay Lake 3,” and “Clover Leaf 1” did not develop an intense blue color. Although the experimenter could witness a faint blue color appearing, the color change may not be evident to the untrained eye. This may be due to the arsenate concentration being below the stannous chloride stain’s minimum detection limit (MDL). Table B-5 presents the results of the sample digestate from the AA spectrometer and the results from the stannous chloride stain in increasing total arsenic concentration. The samples that did not develop an intense blue color with the stannous chloride stain had the lowest arsenic concentrations when analyzed with the AA spectrometer. Therefore, the stain’s MDL should be examined around 2 mg/L arsenate.

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Sample Name AA (mg/kg)

AA Avg. Digestate

Conc. (ppm)

Intense Blue with Stannous Chloride Stain

FHRP 2 149 1.5 NO Briar Bay Lake 3 159 1.5 NO Clover Leaf 1 220 2.2 NO Bunche 2 384 4.0 YES Clover Leaf 3 387 4.0 YES Serena Lakes 4 513 5.4 YES Briar Bay Lake 1 521 5.6 YES Serena Lakes 1 578 5.8 YES Briar Bay Lake 2 643 6.5 YES FHRP 1 652 7.0 YES Colonial Drive 2 742 8.1 YES Devonaire 3 1012 10.0 YES Clover Leaf 2 1224 12.2 YES Colonial Drive 1 1167 13.1 YES Water Oaks 1 1287 13.3 YES Indian Hammock 2 1399 16.4 YES Devonaire 2 1498 16.5 YES Colonial Drive 3 1679 18.0 YES Indian Hammock 1 1670 18.7 YES Serena Lakes 2 1795 19.1 YES Serena Lakes 3 2384 25.5 YES Amelia Earhart 1 3013 30.4 YES Bunche1 3229 34.8 YES Devonaire 1 4852 47.3 YES NOTE: Sample numbers 1 through 4 indicate the component of the playground from which the sample was collected. (1 = Column; 2 = Floor beam; 3 = Secondary support; 4 = Bridge wood).

Table B-5: Sample Results from AA and Stannous Chloride Stain Analysis in order of Increasing Total Arsenic Concentration

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Stannous Chloride Stain Minimum Detection Limit for Arsenate and Phosphate DATE OF EXPERIMENT: August 7, 2005 PURPOSE This experiment was intended to determine the minimum detection limit (MDL) of the stannous chloride stain for arsenate and phosphate. This was necessary in order to better understand the results of applying the stannous chloride stain dissolution method to certain samples. PROCEDURE A calibration curve was established. • Standard solutions were created of differing phosphate concentrations: 0 (blank), 0.1, 0.2,

0.3, 0.4, 0.5, 0.6, 0.7, 1.0, 1.5, 2.0, 2.5, 5.0 ppm. • The original stannous chloride stain phosphate identification method described in Standard

Methods was applied to the standard phosphate solutions. • A spectrophotometer (Hach Spectronic 20, Milton Roy Company) was used to measure and

record the absorbance of the blank and phosphate solutions at wavelength 690 nm. • The visual description of the phosphate solutions were recorded. • A calibration curve was established of measured absorbance vs. phosphate concentration. The phosphate concentration in wood samples was determined. • Four samples were devised:

1.) unfiltered untreated wood soaked for 15 minutes 2.) filtered untreated wood soaked for 15 minutes 3.) unfiltered untreated wood soaked for 24 hours 4.) filtered untreated wood soaked for 24 hours.

• The original stannous chloride stain phosphate identification method described in Standard Methods was applied to the four untreated wood samples.

• A spectrophotometer (Hach Spectronic 20, Milton Roy Company) was used to measure and record the absorbance of the phosphate solutions at wavelength 690 nm.

• The visual description of the phosphate solutions was recorded. • The phosphate concentration in the wood samples was determined using the previously

established calibration curve. This gave a better idea of the approximate MDL of the stannous chloride stain.

The difference in color development on the phosphate solutions between the original stannous chloride stain and the modified stannous chloride stain was determined. • The modified stannous chloride stain was applied to the standard phosphate solutions. • A spectrophotometer (Hach Spectronic 20, Milton Roy Company) was used to measure and

record the absorbance of the phosphate solutions at wavelength 690 nm. o Measurements were performed repeatedly over time.

• The visual description of the phosphate solutions was recorded. The color development by standard arsenate solutions of the modified stannous chloride stain was determined. • Standard solutions were created of differing arsenate concentrations: 0 (blank), 0.1, 0.2, 0.3,

0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 2.5, 5.0 ppm. • The modified stannous chloride stain was applied to the standard arsenate solutions.

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• A spectrophotometer (Hach Spectronic 20, Milton Roy Company) was used to measure and record the absorbance of the arsenate solutions at wavelength 690 nm. o Measurements were performed repeatedly over time.

• The visual description of the arsenate solutions was recorded. A color key was established. • Using the measured absorbance and the visual description of the solutions, the range of

absorbance (at 690 nm) for a specific visual description was determined. DATA

Phosphate Conc (ppm)

Absorbance (λ = 690 nm) Color Description

0.0 0.000 none 0.1 0.148 light blue 0.2 0.270 light blue 0.3 0.404 medium blue 0.4 0.521 medium blue 0.5 0.636 medium blue 0.6 0.725 blue 0.7 0.860 blue 1.0 1.150 blue 1.5 1.550 intense blue 2.0 1.950 intense blue 2.5 >2 intense blue 5.0 >2 dark blue

Table B-6: Measured Absorbance and Visual Color Description of Standard Phosphate Solutions using the Original Stannous Chloride Stain

Sample Calculated Phosphate

Conc (ppm) Absorbance (λ = 690 nm) Color Description

15 min - Unfiltered 0.83 0.880 blue 15 min - Filtered 0.74 0.780 blue 24 hr - Unfiltered 1.80 1.900 blue - intense blue 24 hr - Filtered 1.41 1.490 intense blue Table B-7: Measured Absorbance, Visual Color Description, and Calculated Phosphate Concentration of Untreated Wood Samples using the Original Stannous Chloride Stain

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y = 1.0553xR2 = 0.974

0.00

0.50

1.00

1.50

2.00

2.50

0.0 0.5 1.0 1.5 2.0 2.5

Concentration (ppm)

Abs

orba

nce

Phosphate Standard Untreated Wood Linear (Phosphate Standard)

Figure B-1: Calibration Curve of Measured Absorbance vs. Phosphate Concentration

A-61

Phosphate Concentration (ppm) Time (hr) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 1 1.5 2 2.5 5 0.5 0.000 0.017 0.022 0.035 0.040 0.043 0.061 0.070 0.090 0.112 0.110 0.159 0.2600.75 0.000 0.020 0.030 0.039 0.049 0.054 0.071 0.082 0.108 0.140 0.135 0.192 0.310

1 0.000 0.020 0.033 0.041 0.054 0.060 0.079 0.097 0.125 0.168 0.161 0.222 0.3491.25 0.000 0.013 0.034 0.044 0.060 0.070 0.090 0.107 0.142 0.190 0.190 0.248 0.3881.5 0.000 0.018 0.035 0.048 0.066 0.075 0.096 0.116 0.160 0.208 0.219 0.269 0.4172 0.000 0.018 0.045 0.054 0.069 0.077 0.110 0.134 0.178 0.229 0.232 0.294 0.4493 0.000 0.007 0.017 0.046 0.085 0.090 0.165 0.180 0.229 0.258 0.245 0.300 0.4594 0.000 0.010 0.026 0.060 0.100 0.110 0.171 0.203 0.245 0.270 0.239 0.287 0.4445 0.000 0.005 0.025 0.059 0.091 0.120 0.164 0.220 0.251 0.278 0.235 0.289 0.4306 0.000 0.020 0.041 0.083 0.130 0.140 0.188 0.209 0.263 0.299 0.280 0.308 0.493

Table B-8: Measured Absorbance Readings (λ = 690 nm) for Standard Phosphate Solutions using the Modified Stannous Chloride Stain

0.000

0.050

0.100

0.150

0.200

0.250

0.300

0.350

0.400

0.450

0.500

0 1 2 3 4 5 6 7

Time (hr)

Abs

orba

nce

5.0 ppm PO42.5 ppm PO42.0 ppm PO41.5 ppm PO41.0 ppm PO40.7 ppm PO40.6 ppm PO40.5 ppm PO40.4 ppm PO40.3 ppm PO40.2 ppm PO40.1 ppm PO40 ppm PO4

Figure B-2: Measured Absorbance of Phosphate Solutions vs. Time using the Modified

Stannous Chloride Stain

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Phosphate Concentration (ppm) Time (hr) 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.5 2 2.5 5

0.167 0.000 0.026 0.035 0.048 0.055 0.069 0.090 0.084 0.098 0.148 0.127 0.158 0.175 0.210 0.3250.5 0.000 0.040 0.065 0.092 0.115 0.143 0.191 0.184 0.208 0.250 0.228 0.289 0.309 0.382 0.535

0.75 0.000 0.050 0.079 0.112 0.145 0.178 0.221 0.230 0.259 0.298 0.276 0.351 0.386 0.455 0.6401 0.000 0.043 0.097 0.140 0.175 0.220 0.270 0.273 0.299 0.350 0.330 0.425 0.475 0.550 0.725

1.25 0.000 0.053 0.110 0.154 0.198 0.246 0.287 0.302 0.337 0.395 0.369 0.475 0.530 0.610 0.8101.5 0.000 0.063 0.105 0.163 0.215 0.260 0.303 0.330 0.375 0.445 0.415 0.522 0.585 0.670 0.8902 0.000 0.065 0.117 0.172 0.235 0.292 0.349 0.366 0.427 0.480 0.470 0.600 0.670 0.750 0.9903 0.000 0.093 0.143 0.201 0.257 0.320 0.380 0.415 0.470 0.535 0.535 0.695 0.780 0.860 1.1304 0.000 0.066 0.143 0.202 0.264 0.331 0.408 0.425 0.490 0.570 0.565 0.740 0.840 0.910 1.1705 0.000 0.078 0.146 0.214 0.279 0.348 0.425 0.430 0.494 0.582 0.570 0.750 0.880 0.940 1.1906 0.000 0.081 0.166 0.218 0.300 0.370 0.450 0.441 0.510 0.600 0.595 0.790 0.900 0.990 1.250

Table B-9: Measured Absorbance Readings (λ = 690 nm) for Standard Arsenate Solutions using the Modified Stannous Chloride Stain

0.000

0.200

0.400

0.600

0.800

1.000

1.200

1.400

0 1 2 3 4 5 6 7

Time (hr)

Abs

orba

nce

5.0 ppm AsO42.5 ppm AsO42.0 ppm AsO41.5 ppm AsO41.0 ppm AsO40.9 ppm AsO40.8 ppm AsO40.7 ppm AsO40.6 ppm AsO40.5 ppm AsO40.4 ppm AsO40.3 ppm AsO40.2 ppm AsO40.1 ppm AsO40 ppm AsO4

Figure B-3: Measured Absorbance of Arsenate Solutions vs. Time using the Modified Stannous

Chloride Stain

A-63

Sample Description Color

Description Absorbance (λ = 690 nm) Stannous

Chloride Stain Phosphate or Arsenate

Concentration (ppm)

Time (hr)

0.000 Original Arsenate 0 0.167 0.000 Modified Arsenate 0 0.167 0.000 Original Phosphate 0 0.167 0.000 Original Arsenate 0 0.5 0.000 Modified Arsenate 0 0.5 0.000 Modified Phosphate 0 0.5 0.000 Original Arsenate 0 0.75 0.000 Modified Arsenate 0 0.75 0.000 Modified Phosphate 0 0.75 0.000 Original Arsenate 0 1 0.000 Modified Arsenate 0 1 0.000 Modified Phosphate 0 1 0.000 Modified Arsenate 0 1.25 0.000 Modified Phosphate 0 1.25 0.000 Modified Arsenate 0 1.5 0.000 Modified Phosphate 0 1.5 0.000 Modified Arsenate 0 2 0.000 Modified Phosphate 0 2 0.000 Modified Arsenate 0 3 0.000 Modified Phosphate 0 3 0.000 Modified Arsenate 0 4 0.000 Modified Phosphate 0 4 0.000 Modified Arsenate 0 5 0.000 Modified Phosphate 0 5 0.000 Modified Arsenate 0 6 0.000 Modified Phosphate 0 6 0.005 Modified Phosphate 0.1 5 0.007 Modified Phosphate 0.1 3 0.010 Modified Phosphate 0.1 4 0.013 Modified Phosphate 0.1 1.25 0.017 Modified Phosphate 0.1 0.5 0.017 Modified Phosphate 0.2 3 0.018 Modified Phosphate 0.1 1.5 0.018 Modified Phosphate 0.1 2 0.020 Modified Phosphate 0.1 0.75 0.020 Modified Phosphate 0.1 1 0.020 Modified Phosphate 0.1 6

NONE

0.022 Modified Phosphate 0.2 0.5 0.025 Modified Phosphate 0.2 5 0.026 Modified Arsenate 0.1 0.167 0.026 Modified Phosphate 0.2 4 0.030 Modified Phosphate 0.2 0.75 0.033 Modified Phosphate 0.2 1

FAINT

0.034 Modified Phosphate 0.2 1.25 Table B-10: Sample Absorbance and Associated Visual Color Description

A-64

Sample Description

Color Description

Absorbance (λ = 690 nm) Stannous


Concentration (ppm)

Time (hr)

0.035 Modified Arsenate 0.2 0.167 0.035 Modified Phosphate 0.3 0.5 0.035 Modified Phosphate 0.2 1.5 0.039 Modified Phosphate 0.3 0.75 0.040 Modified Arsenate 0.1 0.5 0.040 Modified Phosphate 0.4 0.5 0.041 Modified Phosphate 0.3 1 0.041 Modified Phosphate 0.2 6 0.043 Modified Phosphate 0.5 0.5 0.043 Modified Arsenate 0.1 1 0.044 Modified Phosphate 0.3 1.25 0.046 Modified Phosphate 0.3 3 0.048 Modified Arsenate 0.3 0.167 0.048 Modified Phosphate 0.3 1.5 0.049 Modified Phosphate 0.4 0.75 0.050 Modified Arsenate 0.1 0.75 0.053 Modified Arsenate 0.1 1.25 0.054 Modified Phosphate 0.5 0.75 0.054 Modified Phosphate 0.4 1 0.054 Modified Phosphate 0.3 2 0.055 Modified Arsenate 0.4 0.167 0.059 Modified Phosphate 0.3 5 0.060 Modified Phosphate 0.5 1 0.060 Modified Phosphate 0.4 1.25 0.060 Modified Phosphate 0.3 4 0.061 Modified Phosphate 0.6 0.5 0.063 Modified Arsenate 0.1 1.5 0.065 Modified Arsenate 0.2 0.5 0.065 Modified Arsenate 0.1 2 0.066 Modified Phosphate 0.4 1.5 0.066 Modified Arsenate 0.1 4 0.069 Modified Arsenate 0.5 0.167 0.069 Modified Phosphate 0.4 2 0.070 Modified Phosphate 0.5 1.25

FAINT

0.070 Modified Phosphate 0.7 0.5 0.071 Modified Phosphate 0.6 0.75 0.075 Modified Phosphate 0.5 1.5 0.077 Modified Phosphate 0.5 2 0.078 Modified Arsenate 0.1 5 0.079 Modified Arsenate 0.2 0.75 0.079 Modified Phosphate 0.6 1 0.081 Modified Arsenate 0.1 6

LIGHT

0.082 Modified Phosphate 0.7 0.75 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

A-65




Concentration (ppm)

Time (hr)

0.083 Modified Phosphate 0.3 6 0.084 Modified Arsenate 0.7 0.167 0.085 Modified Phosphate 0.4 3 0.090 Modified Arsenate 0.6 0.167 0.090 Modified Phosphate 1 0.5 0.090 Modified Phosphate 0.6 1.25 0.090 Modified Phosphate 0.5 3 0.091 Modified Phosphate 0.4 5 0.092 Modified Arsenate 0.3 0.5 0.093 Modified Arsenate 0.1 3 0.096 Modified Phosphate 0.6 1.5 0.097 Modified Arsenate 0.2 1 0.097 Modified Phosphate 0.7 1 0.098 Modified Arsenate 0.8 0.167 0.100 Modified Phosphate 0.4 4 0.105 Modified Arsenate 0.2 1.5 0.107 Modified Phosphate 0.7 1.25 0.108 Modified Phosphate 1 0.75 0.110 Modified Phosphate 2 0.5 0.110 Modified Arsenate 0.2 1.25 0.110 Modified Phosphate 0.6 2 0.110 Modified Phosphate 0.5 4 0.112 Modified Phosphate 1.5 0.5 0.112 Modified Arsenate 0.3 0.75 0.115 Modified Arsenate 0.4 0.5 0.116 Modified Phosphate 0.7 1.5 0.117 Modified Arsenate 0.2 2 0.120 Modified Phosphate 0.5 5 0.125 Modified Phosphate 1 1 0.127 Modified Arsenate 1 0.167 0.130 Modified Phosphate 0.4 6 0.134 Modified Phosphate 0.7 2 0.135 Modified Phosphate 2 0.75 0.140 Modified Phosphate 1.5 0.75 0.140 Modified Arsenate 0.3 1 0.140 Modified Phosphate 0.5 6 0.142 Modified Phosphate 1 1.25 0.143 Modified Arsenate 0.5 0.5 0.143 Modified Arsenate 0.2 3 0.143 Modified Arsenate 0.2 4 0.145 Modified Arsenate 0.4 0.75 0.146 Modified Arsenate 0.2 5 0.148 Modified Arsenate 0.9 0.167

LIGHT

0.148 Original Phosphate 0.1 0.167 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

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Sample Description

Color Description



Concentration (ppm)

Time (hr)

0.154 Modified Arsenate 0.3 1.25 0.158 Modified Arsenate 1.5 0.167 0.159 Modified Phosphate 2.5 0.5 0.160 Modified Phosphate 1 1.5 0.161 Modified Phosphate 2 1 0.163 Modified Arsenate 0.3 1.5 0.164 Modified Phosphate 0.6 5 0.165 Modified Phosphate 0.6 3 0.166 Modified Arsenate 0.2 6 0.168 Modified Phosphate 1.5 1 0.171 Modified Phosphate 0.6 4 0.172 Modified Arsenate 0.3 2 0.175 Modified Arsenate 0.4 1 0.175 Modified Arsenate 2 0.167 0.178 Modified Arsenate 0.5 0.75 0.178 Modified Phosphate 1 2 0.180 Modified Phosphate 0.7 3 0.184 Modified Arsenate 0.7 0.5 0.188 Modified Phosphate 0.6 6 0.190 Modified Phosphate 1.5 1.25 0.190 Modified Phosphate 2 1.25 0.191 Modified Arsenate 0.6 0.5 0.192 Modified Phosphate 2.5 0.75 0.198 Modified Arsenate 0.4 1.25 0.201 Modified Arsenate 0.3 3 0.202 Modified Arsenate 0.3 4 0.203 Modified Phosphate 0.7 4 0.208 Modified Arsenate 0.8 0.5 0.208 Modified Phosphate 1.5 1.5 0.209 Modified Phosphate 0.7 6 0.210 Modified Arsenate 2.5 0.167 0.214 Modified Arsenate 0.3 5 0.215 Modified Arsenate 0.4 1.5 0.218 Modified Arsenate 0.3 6 0.219 Modified Phosphate 2 1.5 0.220 Modified Phosphate 0.7 5

LIGHT

0.220 Modified Arsenate 0.5 1 0.221 Modified Arsenate 0.6 0.75 0.222 Modified Phosphate 2.5 1 0.228 Modified Arsenate 1 0.5 0.229 Modified Phosphate 1.5 2 0.229 Modified Phosphate 1 3

MEDIUM

0.230 Modified Arsenate 0.7 0.75 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

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Concentration (ppm)

Time (hr)

0.232 Modified Phosphate 2 2 0.235 Modified Arsenate 0.4 2 0.235 Modified Phosphate 2 5 0.239 Modified Phosphate 2 4 0.245 Modified Phosphate 2 3 0.245 Modified Phosphate 1 4 0.246 Modified Arsenate 0.5 1.25 0.248 Modified Phosphate 2.5 1.25 0.250 Modified Arsenate 0.9 0.5 0.251 Modified Phosphate 1 5 0.257 Modified Arsenate 0.4 3 0.258 Modified Phosphate 1.5 3 0.259 Modified Arsenate 0.8 0.75 0.260 Modified Phosphate 5 0.5 0.260 Modified Arsenate 0.5 1.5 0.263 Modified Phosphate 1 6 0.264 Modified Arsenate 0.4 4 0.269 Modified Phosphate 2.5 1.5 0.270 Original Phosphate 0.2 0.167 0.270 Modified Arsenate 0.6 1 0.270 Modified Phosphate 1.5 4 0.273 Modified Arsenate 0.7 1 0.276 Modified Arsenate 1 0.75 0.278 Modified Phosphate 1.5 5 0.279 Modified Arsenate 0.4 5 0.280 Modified Phosphate 2 6 0.287 Modified Arsenate 0.6 1.25 0.287 Modified Phosphate 2.5 4 0.289 Modified Arsenate 1.5 0.5 0.289 Modified Phosphate 2.5 5 0.292 Modified Arsenate 0.5 2 0.294 Modified Phosphate 2.5 2 0.298 Modified Arsenate 0.9 0.75 0.299 Modified Phosphate 1.5 6 0.299 Modified Arsenate 0.8 1 0.300 Modified Phosphate 2.5 3 0.300 Modified Arsenate 0.4 6 0.302 Modified Arsenate 0.7 1.25 0.303 Modified Arsenate 0.6 1.5 0.308 Modified Phosphate 2.5 6 0.309 Modified Arsenate 2 0.5 0.310 Modified Phosphate 5 0.75 0.315 Original Arsenate 0.1 1

MEDIUM

0.320 Modified Arsenate 0.5 3 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

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Sample Description

Color Description



Concentration (ppm)

Time (hr)

0.325 Modified Arsenate 5 0.167 0.330 Modified Arsenate 1 1 0.330 Modified Arsenate 0.7 1.5 0.331 Modified Arsenate 0.5 4 0.337 Modified Arsenate 0.8 1.25 0.348 Modified Arsenate 0.5 5 0.349 Modified Phosphate 5 1 0.349 Modified Arsenate 0.6 2 0.350 Original Arsenate 0.1 0.75 0.350 Modified Arsenate 0.9 1 0.351 Modified Arsenate 1.5 0.75 0.366 Modified Arsenate 0.7 2 0.369 Original Arsenate 0.1 0.5 0.369 Modified Arsenate 1 1.25 0.370 Modified Arsenate 0.5 6 0.371 Original Arsenate 0.1 0.167 0.375 Modified Arsenate 0.8 1.5 0.380 Modified Arsenate 0.6 3 0.382 Modified Arsenate 2.5 0.5 0.386 Modified Arsenate 2 0.75 0.388 Modified Phosphate 5 1.25

MEDIUM

0.395 Modified Arsenate 0.9 1.25 0.404 Original Phosphate 0.3 0.167 0.408 Modified Arsenate 0.6 4 0.415 Modified Arsenate 1 1.5 0.415 Modified Arsenate 0.7 3 0.417 Modified Phosphate 5 1.5 0.425 Modified Arsenate 1.5 1 0.425 Modified Arsenate 0.7 4 0.425 Modified Arsenate 0.6 5 0.427 Modified Arsenate 0.8 2 0.430 Modified Phosphate 5 5 0.430 Modified Arsenate 0.7 5 0.441 Modified Arsenate 0.7 6 0.444 Modified Phosphate 5 4 0.445 Modified Arsenate 0.9 1.5 0.449 Modified Phosphate 5 2 0.450 Modified Phosphate 0.2 2 0.450 Modified Arsenate 0.6 6 0.455 Modified Arsenate 2.5 0.75 0.459 Modified Phosphate 5 3 0.470 Modified Arsenate 1 2

BLUE

0.470 Modified Arsenate 0.8 3 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

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Concentration (ppm)

Time (hr)

0.475 Modified Arsenate 2 1 0.475 Modified Arsenate 1.5 1.25 0.480 Modified Arsenate 0.9 2 0.490 Modified Arsenate 0.8 4 0.493 Modified Phosphate 5 6 0.494 Modified Arsenate 0.8 5 0.510 Modified Arsenate 0.8 6 0.521 Original Phosphate 0.4 0.167 0.522 Modified Arsenate 1.5 1.5 0.530 Modified Arsenate 2 1.25 0.535 Modified Arsenate 5 0.5 0.535 Modified Arsenate 0.9 3 0.535 Modified Arsenate 1 3 0.545 Original Arsenate 0.2 1 0.550 Modified Arsenate 2.5 1 0.555 Original Arsenate 0.2 0.75 0.565 Modified Arsenate 1 4 0.570 Modified Arsenate 0.9 4 0.570 Modified Arsenate 1 5 0.575 Original Arsenate 0.2 0.5 0.582 Modified Arsenate 0.9 5 0.585 Modified Arsenate 2 1.5 0.595 Modified Arsenate 1 6 0.600 Modified Arsenate 1.5 2 0.600 Modified Arsenate 0.9 6 0.610 Modified Arsenate 2.5 1.25 0.636 Original Phosphate 0.5 0.167 0.640 Modified Arsenate 5 0.75 0.645 Original Arsenate 0.2 0.167 0.670 Modified Arsenate 2.5 1.5 0.670 Modified Arsenate 2 2 0.695 Modified Arsenate 1.5 3 0.720 Original Arsenate 0.3 1 0.725 Original Phosphate 0.6 0.167 0.725 Modified Arsenate 5 1 0.740 Original Arsenate 0.3 0.75 0.740 Modified Arsenate 1.5 4 0.750 Original Arsenate 0.3 0.5 0.750 Modified Arsenate 2.5 2 0.750 Modified Arsenate 1.5 5

0.780 Original Phosphate 0.74 0.25 - filtered

0.780 Modified Arsenate 2 3 0.790 Modified Arsenate 1.5 6

BLUE

0.810 Modified Arsenate 5 1.25 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

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Concentration (ppm)

Time (hr)

0.840 Modified Arsenate 2 4 0.860 Original Arsenate 0.3 0.167 0.860 Original Phosphate 0.7 0.167 0.860 Modified Arsenate 2.5 3

0.880 Original Phosphate 0.83 0.25 - unfiltered

0.880 Modified Arsenate 2 5 0.890 Modified Arsenate 5 1.5 0.900 Modified Arsenate 2 6 0.920 Original Arsenate 0.4 1 0.920 Modified Arsenate 2.5 4 0.925 Original Arsenate 0.4 0.75 0.940 Original Arsenate 0.4 0.5 0.940 Modified Arsenate 2.5 5 0.990 Modified Arsenate 5 2 0.990 Modified Arsenate 2.5 6 1.030 Original Arsenate 0.4 0.167 1.130 Original Arsenate 0.5 0.75 1.130 Original Arsenate 0.5 1

BLUE

1.130 Modified Arsenate 5 3 1.150 Original Arsenate 0.5 0.5 1.150 Original Phosphate 1 0.167 1.170 Modified Arsenate 5 4 1.190 Modified Arsenate 5 5 1.220 Original Arsenate 0.5 0.167 1.250 Modified Arsenate 5 6 1.280 Original Arsenate 0.6 0.75 1.290 Original Arsenate 0.6 0.5 1.290 Original Arsenate 0.6 1 1.330 Original Arsenate 0.6 0.167 1.430 Original Arsenate 0.7 0.75 1.450 Original Arsenate 0.7 0.5 1.450 Original Arsenate 0.7 1 1.490 Original Arsenate 0.7 0.167 1.490 Original Phosphate 1.41 24 - filtered 1.550 Original Phosphate 1.5 0.167 1.600 Original Arsenate 0.8 0.167 1.600 Original Arsenate 0.8 0.5 1.600 Original Arsenate 0.8 0.75 1.600 Original Arsenate 0.8 1 1.800 Original Arsenate 0.9 0.5 1.800 Original Arsenate 0.9 0.75 1.800 Original Arsenate 0.9 1

INTENSE

1.900 Original Arsenate 0.9 0.167 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

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Concentration (ppm)

Time (hr)

1.900 Original Arsenate 1 0.5 1.900 Original Arsenate 1 0.75 1.900 Original Arsenate 1 1

1.900 Original Phosphate 1.8 24 - unfiltered

1.950 Original Phosphate 2 0.167 2.000 Original Arsenate 1 0.167

> 2.000 Original Arsenate 1.5 0.167 > 2.000 Original Arsenate 2 0.167 > 2.000 Original Phosphate 2.5 0.167 > 2.000 Original Arsenate 1.5 0.5 > 2.000 Original Arsenate 1.5 0.75 > 2.000 Original Arsenate 1.5 1 > 2.000 Original Phosphate 5 0.167

>> 2.000 Original Arsenate 2.5 0.167 >> 2.000 Original Arsenate 5 0.167 >> 2.000 Original Arsenate 2 0.5 >> 2.000 Original Arsenate 2.5 0.5 >> 2.000 Original Arsenate 5 0.5 >> 2.000 Original Arsenate 2 0.75 >> 2.000 Original Arsenate 2.5 0.75 >> 2.000 Original Arsenate 5 0.75 >> 2.000 Original Arsenate 2 1 >> 2.000 Original Arsenate 2.5 1

INTENSE

>> 2.000 Original Arsenate 5 1 Table B-10 (con’d): Sample Absorbance and Associated Visual Color Description

Color Description Absorbance Range

(λ = 690 nm) None 0 to 0.024 Faint 0.025 to 0.070 Light 0.071 to 0.220

Medium 0.221 to 0.399 Blue 0.400 to 1.149

Intense 1.150 to ∞ Table B-11: Absorbance Range and Associated Visual Color Description

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Figure B-4: Phosphate Solutions (left to right – 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 1.0, 1.5, 2.0,

2.5, and 5.0 ppm) Subjected to the Original (top) and Modified (bottom) Stannous Chloride Stain

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Figure B-5: Arsenate Solutions (left to right – 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 1.0, 1.5, 2.0, 2.5,

and 5.0 ppm) Subjected to the Original (top) and Modified (bottom) Stannous Chloride Stain CONCLUSION This experiment showed that the stannous chloride stain dissolution method was able to identify arsenate and phosphate at low concentrations of 0.1 to 0.2 mg/L. The color change witnessed at these low concentrations was due to physically adding arsenate or phosphate to the solution. However, in using the modified stannous chloride stain to detect arsenate in wood samples, it was able to identify arsenate concentrations only as low as 2.0 mg/L during the field test. Additionally, the modified stannous chloride stain did not react with the natural phosphate concentration in untreated wood when soaked for 30 minutes in the “Testing Shredded Wood Samples in Solution” experiment (see Appendix A). The phosphate concentration in the untreated shredded wood solution when soaked for 15 minutes was 0.8 mg/L. A possible explanation as to why the modified stannous chloride stain reacted with low concentrations of 0.1 to 0.2 ppm of “artificial” phosphate or arsenate, but did not react with natural phosphate concentrations up to 0.8 mg/L and arsenate concentrations up to 2 mg/L was because of the color of the wood. The presence of wood in solution prevented any faint blue color from appearing because the wood was yellow, and thus was able to mask it. The natural color of wood allowed the stain to ignore the natural phosphate in the wood and develop an intense blue color only with

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unreasonably high arsenate concentrations caused by added arsenate preservative. As can be more easily seen in Figures B-4 and B-5 at the phosphate and arsenate concentration of 5.0 ppm in the modified stannous chloride stain, the blue color that developed with the arsenate was much deeper than that with the phosphate. Although a reduction in blue color occurred in both the phosphate and arsenate when changing from the original stannous chloride stain to the modified stain, the stannous chloride stain develops a much deeper blue color when reacting with arsenate. Thus, it allowed abnormally high concentrations of arsenate to be detected and not the phosphate concentrations naturally present in the wood matrix. Therefore, the MDL of the modified stannous chloride stain for phosphate was determined to be approximately 0.8 mg/L and for arsenate 2 mg/L.

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Stannous Chloride Stain Shelf Life New Reagents: • Ammonium Molybdate (made on November 15, 2004) • Stannous Chloride (made on November 14, 2004) PURPOSE Testing the combined stannous chloride stain over the period of six months determined the shelf life of the stain in both application methods, Dissolution Method and Whole Wood Application. Reaction time and intensity of color were taken into consideration. The final objective was to determine when the stain loses its effectiveness of detecting only arsenate. There was increased attentiveness to the Dissolution Method because of its higher consistency and lower reaction time. ADDITIONAL REAGENTS • Combined ammonium molybdate and stannous chloride reagent

o 1 part stannous chloride reagent was added to 8 parts ammonium molybdate reagent, and mixed.

• Combined ammonium molybdate and stannous chloride reagent with distilled water o 2 parts combined ammonium molybdate and stannous chloride reagent was added to 1

part distilled water, and mixed. PROCEDURE • Stannous chloride stain was tested every two weeks for six months. • Reaction times, color, and color intensity were recorded for the Dissolution Method and

Whole Wood Application. o Other factors taken into consideration were also be noted, such as the absorbance time,

the time when an intense blue color was achieved, variations in wood application sites, etc.

• Start time was defined as the time at which the stain first makes contact with the sample • Stop time was defined as the time at which a color change was first noticeable.

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Preliminary Stannous Chloride Stain Test – Dissolution Method DATE OF EXPERIMENT: November 16, 2004 PURPOSE This preliminary testing was performed to determine if the new reagents (ammonium molybdate and stannous chloride) gave the same results as previously seen. Only the Dissolution Method was tested because of it has the higher consistency in reaction time (~12 minutes). PROCEDURE • Dissolution Method

o Reagents Separated (Untreated and 4.0 kg/m3 CCA) o Reagents Combined (Untreated and 4.0 kg/m3 CCA)

DATA

Reagents Untreated 4.0 kg/m3 CCA

Separated faint gray [instantly] intense blue [instantly, faded to light blue over 60 m]

Combined nc faint gray-blue

[20 m, intensified to medium gray-blue over 60 m]

Table B-12: Change in Color, Color Intensity, and Reaction Times of Dissolution Samples

Figure B-6: Picture of Dissolution Samples, Initial

Figure B-7: Picture of Dissolution Samples, 20 minutes

Untreated UntreatedCCA CCA


SEPARATED COMBINED

SEPARATED COMBINED

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Figure B-10: Picture of Dissolution Samples, 60 minutes CONCLUSION Unfortunately, this experiment with the new reagents using the Dissolution Method did not follow previous similar experiments. In this experiment, 4.0 kg/m3 CCA-treated wood with the combined reagent reacted in 20 minutes and a medium gray-blue color developed in 60 minutes. Usually, an initial color change could be witnessed at approximately 12 minutes while a blue color developed before 30 minutes. The untreated wood with the combined reagent followed previous experiments where there was no observed color change. The separated reagent samples in this experiment also did not follow previous experiments. The 4.0 kg/m3 CCA-treated wood sample with the separated reagents in this experiment exhibited an intense blue color instantly, which subsequently faded over the period of 60 minutes. Many previous experiments showed that this sample would usually develop the intense blue color instantly, and


CCA CCAUntreated Untreated


SEPARATED

SEPARATED

COMBINED

COMBINED

SEPARATED COMBINED

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fade over the period of 24 hours or more. Finally, the untreated wood sample with separated reagents also did not follow previous experiments. In this experiment, the sample turned a faint gray instantly and maintained that color for 60 minutes. Previously, this sample would have turned an intense blue instantly and fade over the period of 24 hours or more. Although this experiment was not closely observed for 24 hours, it should be noted that the both untreated wood samples relatively maintained their color or lack of color. For the 4.0 kg/m3 CCA-treated wood samples, the separated reagents sample faded to a light blue, while the combined reagents sample intensified to a medium blue-gray. Because of the differences in reaction time and color development witnessed between this experiment with new reagents and previous experiments, the start date for determining the shelf life of the stannous chloride stain should be postponed until more consistent results are given. The quality of the new reagents should be examined more closely. If necessary, new reagents should be created. [Problems were identified and corrected. See “Stannous Chloride Stain Mixing Time #1.”]

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Stannous Chloride Stain Shelf Life Test DATE OF EXPERIMENT: December 10, 2004 PURPOSE This test was intended to determine if the new reagents (ammonium molybdate and stannous chloride) would give results consistent with the preliminary testing performed on November 16, 2004 or with previous experiments. Both the dissolution method and the whole wood application method was tested and monitored for two hours. This experiment was intended to determine if the blue color became noticeable and intense in a reasonable time frame. For the dissolution method, a reasonable time frame was 15 minutes for the color to become noticeable and 60 minutes for the color to become intense. For the whole wood application method, the time frame was 30 minutes and 60 minutes, respectively. PROCEDURE • Samples were monitored and any color change was noted at time 0, 15, 30, 45, 60, 90, and

120 minutes. • Dissolution Method

o Reagents Combined Untreated – 3 trials 4.0 kg/m3 CCA – 3 trials

• Whole Wood (Drop) Application o Reagents Combined

Untreated – 3 trials 4.0 kg/m3 CCA – 3 trials

DATA

Untreated 4.0 kg/m3 CCA Time (min) 1 2 3 1 2 3

0 nc nc nc nc nc nc 15 nc nc nc faint blue faint blue faint blue 30 nc nc nc lt. blue lt. blue lt. blue 45 nc nc nc med. blue med. blue med. blue 60 nc nc nc blue blue blue 90 nc nc nc blue blue blue 120 nc nc nc blue blue blue

nc = no change

Table B-13: Change in Color and Color Intensity of Dissolution Samples

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Untreated 4.0 kg/m3 CCA Time (min) 1 2 3 1 2 3

0

15

30

45

60

90

120

Table B-14: Pictures of Dissolution Samples

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Figure B-11: Picture of Dissolution Method, Approximate Maximum Intensity, 5 hours

Untreated 4.0 kg/m3 CCA Time

(min) 1 2 3 1 2 3

0 nc nc nc nc nc nc

15 nc nc nc nc nc nc

30 nc nc nc nc nc nc

45 nc nc nc edges blue edges blue edges blue

60 gray gray; compact wood blue-green

gray; compact wood blue-green faint blue faint blue faint blue

90 gray gray; compact wood blue-green

gray; compact wood blue-green lt. blue lt. blue lt. blue

120 gray-blue gray; compact wood blue-green

gray; compact wood blue-green lt. blue lt. blue lt. blue

nc = no change

Table B-15: Change in Color and Color Intensity of Whole Wood Samples

Untreated CCA

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Trial Time (min) Wood Type 1 2 3

0

Untreated

CCA

15

Untreated

CCA

30

Untreated

CCA

45

Untreated

CCA

60

Untreated

CCA

90

Untreated

CCA

120

Untreated

CCA

Table B-16: Pictures of Whole Wood Application

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CONCLUSION This experiment determined that the new reagents do, in fact, work as intended in the dissolution method. However, they were not optimal for whole wood application. Because this experiment was consistent with previous results, determination of the shelf life of the stannous chloride stain began with this experiment and the combined reagent will be tested every two weeks. FOLLOW-UP DATE: December 11, 2004 Approximately 500 mL of combined reagent was produced for future testing. The quality of the combined reagent was subsequently tested to ensure a reaction time consistent with the previous experiments, excluding the experiment conducted on November 16, 2004. For the dissolution method, the time at which the blue color was noticeable was approximately 16 minutes, and the time at which an intense blue color developed was around 55 minutes. DATE: December 19, 2004 The combined stannous chloride stain was tested in order to possibly reduce the reaction time. However, the results from this test were similar to that of the experiment performed on November 16, 2004, where the reaction time for the dissolution method was greatly extended (>30 minutes) and the time to reach an intense blue color took over 2 hours. Because two experiments had similar poor results, it was determined to add more molybdenum to the already combined reagent, in equal parts, and then test that mixture. This led to a reaction time of 14 minutes, and an intense blue color developed within 60 minutes. Adding molybdenum to the already combined reagent gave better results, which may be evidence that the reduction reaction involved in the stannous chloride stain is reducing the molybdenum too much. This causes the mean oxidation state of the molybdenum in the arsenate-molybdenum complex to be lower than +6 to +5; thus, it reduces the effectiveness of the stannous chloride stain to detect arsenate within the intended time frame. However, it should be noted that over-reduction of the stain does not affect its ability to detect arsenate, but it will take more time in order to do so. In addition, if too much molybdenum was added to the already combined stain, then it will increase the mean oxidation state of the molybdenum in the arsenate-molybdenum complex to be closer to +6 and +5, which is the mean oxidation state of the molybdenum for its original purpose to detect phosphate. In other words, the stain will begin to act as if the reagents were added separately, begin to detect phosphate, and no longer be arsenate-specific. The already combined reagent was prepared 8 days ago, and there was a huge increase in the reaction time. Therefore, another combined reagent was created and will be tested tomorrow to determine if the stain’s reaction time is maintained for at least one day since the reagents were combined. The combined reagent that was prepared today did not react with untreated wood, and its reaction time with 4.0 kg/m3 CCA-treated wood was approximately 12 minutes. An intense blue color developed in 52 minutes.

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DATE: December 20, 2004 The combined reagent that was created on December 19, 2004 was tested and resulted in a reaction time of 31 minutes 30 seconds. An intense blue color did not develop within two hours. This large increase in reaction time indicates that there is no further need in attempting to determine if the stannous chloride and ammonium molybdate reagents combined in an 1 to 8 ratio is able to be stored. The two reagents should be stored separately; therefore, the shelf life of the reagents should be determined. Another possibility would be to determine the shelf life and storage capability of preparing the combined reagent and adding it directly to water in a sample vial. It would then be necessary to determine how long the reagents must be mixed for in order to have an ideal reaction time when wood is added. Another option would be to reevaluate the mixture of stannous chloride and ammonium molybdate reagents. Although it was already determined that the optimal ratio of stannous chloride to ammonium molybdate is 8 to 1, storage was not considered at the time. Therefore, if the ratio was reevaluated and then the mixtures stored for a certain amount of time, it may be possible to determine what combined mixture of stannous chloride and ammonium molybdate would be able to be stored for extended periods of time. This would partially involve determining the ideal mean oxidation state for detecting arsenate, and then ensuring that there is enough stannous chloride to reduce the molybdenum in the complex to that mean oxidation state without over-reducing it. [Problems were identified and corrected. See “Stannous Chloride Stain Mixing Time #1.”]

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Revised Stannous Chloride Stain Shelf Life New Reagents: • Ammonium Molybdate (made on February 24, 2005) • Stannous Chloride (made on February 24, 2005) PURPOSE Testing the stannous chloride stain over the period of six months (26 weeks) would determine the shelf life of the stain in the Dissolution Method. Reaction time and intensity of color was taken into consideration. The final objective was to determine when the stain lost its effectiveness of detecting only arsenate. Certain revisions were made in order to simplify determining the shelf life of the stannous chloride stain:

1.) The reagents were maintained in their separate storage containers until right before testing due to the increased reaction time witnessed in the previous shelf life determination attempt.

2.) The Whole Wood Application method was removed from the shelf life test because of the increased variability in reaction time, color, and color intensity with untreated and CCA-treated wood. Multiple variables arose in the previous shelf life determination attempt that need to be reconsidered prior to evaluating the Whole Wood Application method, such as absorption of the stain into the wood due to uneven wood density and porosity, uneven chemical preservative treatment distribution in the wood, and effects of temperature (i.e. sunlight) in a real-life situation.

PROCEDURE • Stannous chloride stain Dissolution Method will be tested every two weeks for six months.

o Untreated wood was tested every two weeks for six months. o CCA-treated wood, 4.0 kg/m3, was tested every two weeks for six months. o Borate, ACQ, and CBA treated wood was tested every four weeks for six months. o CC, CDDC, and 40 kg/m3 CCA-treated wood was tested at the end of the testing period

(six months). o NOTE: All wood samples obtained were shredded wood or sawdust of new wood.

• Reaction times, color, and color intensity were recorded for the Dissolution Method o Other factors taken into consideration were also be noted, such as the time when an

intense blue color is achieved, mixing time (the duration of time the reagents were allowed to interact with each other prior to adding the combined reagents to the sample vial), and any unexpected variables that may arise in the course of shelf life testing.


• Start time was defined as the time at which the stain first makes contact with the sample. • The stop time was defined as the time the sample solution begins to change color, or when a

faint to light blue color appeared. • The noticeable time was defined as the time the color of the sample solution appeared light to

medium blue.

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o Noticeable time was an added revision to the previous shelf life determination attempt in order to prevent bias and keep the experiment as similar as possible to a real-life situation where there may be many first-time users.

SHELF LIFE, START DATE: February 25, 2005 SHELF LIFE, END DATE: August 26, 2005 DISSOLUTION METHOD PROCEDURE: • 8 parts ammonium molybdate reagent were added to every 1 part stannous chloride reagent,

mixed, and let stand for a defined mixing time. • 9 drops of the combined reagents were added to 10 mL distilled water in a 20-mL sample

vial. • 0.5 g of sample wood was added to the sample vial, and mixed occasionally.

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Revised Stannous Chloride Stain Shelf Life Test – 0 Weeks DATE OF EXPERIMENT: February 25, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 6 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop nc nc nc Borate Noticeable nc nc nc Stop nc nc nc ACQ Noticeable nc nc nc Stop nc nc nc CBA Noticeable nc nc nc Stop 29:25 27:00 17:00 CCA, 4.0 kg/m3 Noticeable 40:25 31:26 n/a

NOTE: mm:ss nc = no change n/a = not available Table B-17: Reaction Time – 0 Weeks

APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours DISCUSSION: The reaction times for the samples were somewhat higher than what was seen in previous experiments. This may be due to the mixing time being too high or inconsistent mixing.

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Revised Stannous Chloride Stain Shelf Life Test – 2 Weeks DATE OF EXPERIMENT: March 11, 2005 TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 6 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop 13:32 13:03 12:38 CCA, 4.0 kg/m3 Noticeable 17:40 17:23 16:36

NOTE: mm:ss nc = no change Table B-18: Reaction Time – 2 Weeks

APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: >12 hours DISCUSSION: The reaction time for the samples were similar to what was seen in previous experiments, but the time it takes the sample to reach maximum intensity is too long. In this experiment, the sample reached a noticeable light blue color, but then remained at that same color intensity. An intense blue color did not develop in the usual time frame of 4 to 5 hours, but instead required it to stand overnight. This may be due to allowing the chemicals to have too long of a mixing time or the degree of mixing was too intense, which would over-reduce the molybdenum. A more uniform mixing method should be established for the remainder of the shelf life testing.

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Revised Stannous Chloride Stain Shelf Life Test – 4 Weeks DATE OF EXPERIMENT: March 25, 2005 TYPES OF WOOD TESTED: Untreated, ACQ, CBA, 4.0 kg/m3 CCA

*NOTE: Borate treated wood should have been tested at this time but no more borate sawdust available to be tested, and attempts to create more sawdust was prevented by unforeseen circumstances causing the wood shop to close. Therefore, borate treated wood was excluded from stain shelf life testing until further notice.

SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 5 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop nc nc nc ACQ Noticeable nc nc nc Stop nc nc nc CBA Noticeable nc nc nc Stop 15:08 14:48 15:38 CCA, 4.0 kg/m3 Noticeable 54:32 54:12 53:52


APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours DISCUSSION: The reaction time for the samples was somewhat higher than what was seen in previous experiments. In this experiment, the noticeable time was determined by a person unfamiliar with the purpose of the stain. The person was told to identify when s/he felt that any of the sample vials changed color. Because the person indicated the reaction time to be longer than previous experiments, it is advised that a color chart be supplied to any person desiring to use the stain. Although the reaction time provided by the person unfamiliar with the stain was longer than usual, the stain’s ability to identify CCA-treated wood from the other sample wood types was still discernible. Another factor that may have caused an increase in the reaction time is the mixing time was too high or the degree of mixing was too intense.

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Revised Stannous Chloride Stain Shelf Life Test – 6 Weeks DATE OF EXPERIMENT: April 8, 2005 TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 5 minutes



APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 4 hours DISCUSSION: The stop time was lower than what was seen in previous experiments; however, the noticeable time and color intensity for the samples were consistent with previous results.

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Revised Stannous Chloride Stain Shelf Life Test – 8 Weeks DATE OF EXPERIMENT: April 22, 2005 TYPES OF WOOD TESTED: Untreated, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 5 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop nc nc nc ACQ Noticeable nc nc nc Stop nc nc nc CBA Noticeable nc nc nc Stop 14:21 14:02 13:40 CCA, 4.0 kg/m3 Noticeable 32:25 32:06 31:44


APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours DISCUSSION: The reaction time and color intensity for the samples were consistent with what was seen in previous experiments.

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Revised Stannous Chloride Stain Shelf Life Test – 10 Weeks DATE OF EXPERIMENT: May 6, 2005 TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 5 minutes




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Revised Stannous Chloride Stain Shelf Life Test – 12 Weeks DATE OF EXPERIMENT: May 20, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 5 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop nc nc nc Borate Noticeable nc nc nc Stop nc nc nc ACQ Noticeable nc nc nc Stop nc nc nc CBA Noticeable nc nc nc Stop 13:44 14:54 14:32 CCA, 4.0 kg/m3 Noticeable 44:34 42:20 40:27



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Revised Stannous Chloride Stain Shelf Life Test – 14 Weeks DATE OF EXPERIMENT: June 3, 2005 TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All sawdust samples MIXING TIME: Approx. 5 minutes



APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours DISCUSSION: The reaction times for the samples were somewhat higher than what was seen in previous experiments. This may be due to experimental variability in human error or the reagents may be losing their effectiveness.

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Revised Stannous Chloride Stain Shelf Life Test – 16 Weeks DATE OF EXPERIMENT: June 17, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: Untreated shredded wood; Borate, ACQ, CBA, and 4.0

kg/m3 CCA sawdust MIXING TIME: Approx. 5 minutes




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Revised Stannous Chloride Stain Shelf Life Test – 18 Weeks DATE OF EXPERIMENT: July 1, 2005 PERFORMED BY: Colleen Block TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: Untreated shredded wood; 4.0 kg/m3 CCA sawdust MIXING TIME: Approx. 5 minutes



APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours DISCUSSION: The reaction time for the samples was somewhat higher than what was seen in previous experiments. This may be due to experimental variability in human error, a different individual performing the experiment, or the reagents may be losing their effectiveness.

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Revised Stannous Chloride Stain Shelf Life Test – 20 Weeks DATE OF EXPERIMENT: July 15, 2005 PERFORMED BY: Colleen Block TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: Untreated shredded wood; Borate, ACQ, CBA, and 4.0




APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours 15 minutes DISCUSSION: The reaction time and color intensity for the samples were consistent with what was seen in previous experiments.

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Revised Stannous Chloride Stain Shelf Life Test – 22 Weeks DATE OF EXPERIMENT: July 1, 2005 PERFORMED BY: Colleen Block TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: Untreated shredded wood; 4.0 kg/m3 CCA sawdust MIXING TIME: Approx. 5 minutes

Trial Wood Type Time 1 2 3 Stop nc nc Nc Untreated Noticeable nc nc Nc Stop 16:13 15:51 15:34 CCA, 4.0 kg/m3 Noticeable 34:05 33:43 33:26



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Revised Stannous Chloride Stain Shelf Life Test – 24 Weeks DATE OF EXPERIMENT: August 12, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: Untreated shredded wood; Borate, ACQ, CBA, and 4.0





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Revised Stannous Chloride Stain Shelf Life Test – 26 Weeks DATE OF EXPERIMENT: August 31, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA, 40 kg/m3 CCA,

ACZA SAWDUST OR SHREDDED WOOD: Untreated and 40 kg/m3 CCA shredded wood; Borate,

ACQ, CBA, 4.0 kg/m3 CCA, and ACZA sawdust MIXING TIME: Approx. 5 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop nc nc nc Borate Noticeable nc nc nc Stop nc nc nc ACQ Noticeable nc nc nc Stop nc nc nc CBA Noticeable nc nc nc Stop 09:40 09:25 09:10 CCA, 4.0 kg/m3 Noticeable 20:30 20:15 20:00 Stop 08:45 08:30 08:15 CCA, 40 kg/m3

Noticeable 12:45 12:30 12:15 Stop 12:30 12:15 12:00 ACZA Noticeable 23:00 22:45 22:30


APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours (CCA-treated wood);

2 hours (ACZA-treated wood) DISCUSSION: The stannous chloride stain’s shelf life could not be tested at exactly 26 weeks due to circumstances beyond control. The shelf life test was performed at the earliest possible date on August 31, 2005, approximately 5 days after the scheduled test date. The reaction time and color intensity for the samples were consistent with what was seen in previous experiments. Although ACZA-treated wood reacted and developed a noticeable blue color, it did not form an intense blue. The maximum color intensity of ACZA-treated wood with the stannous chloride stain was a light blue.

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Revised Stannous Chloride Stain Shelf Life Test – Overall

Time Trial 1 Trial 2 Trial 3 AVERAGE Weeks

Stop Noticeable Stop Noticeable Stop Noticeable Stop Noticeable 0 29:25 40:25 27:00 31:26 17:00 n/a 24:28 35:56 2 13:32 17:40 13:03 17:23 12:38 16:36 13:04 17:13 4 15:08 54:32 14:48 54:12 15:38 53:52 15:11 54:12 6 07:29 30:59 07:06 30:46 06:44 30:06 07:06 30:37 8 14:21 32:25 14:02 32:06 13:40 31:44 14:01 32:15 10 14:04 41:02 13:45 40:43 13:25 40:23 13:45 40:43 12 13:44 44:34 14:54 42:20 14:32 40:27 14:23 42:27 14 24:26 44:26 23:44 43:44 23:56 42:56 24:02 43:42 16 13:30 35:00 12:51 34:48 12:39 34:21 13:00 34:43 18 18:31 44:49 17:12 43:30 16:39 42:57 17:27 43:45 20 15:40 33:44 15:20 36:29 14:55 36:05 15:18 35:26 22 16:13 34:05 15:51 33:43 15:34 33:26 15:53 33:44 24 13:39 17:39 13:18 17:18 13:01 17:01 13:19 17:19 26 09:40 20:30 09:25 20:15 09:10 20:00 09:25 20:15

NOTE: mm:ss n/a = not available

Table B-31: Progression of Stannous Chloride Stain Reaction Time with 4.0 kg/m3 CCA-Treated Wood during Shelf-Life Test

Weeks Approx. Time of Max.

Intensity (hours) 0 5 2 >12* 4 5 6 4 8 5 10 5 12 5 14 5 16 5 18 5 20 5.25 22 5 24 5 26 5

NOTE: *In week 2, the stain may have had too long of a mixing time causing the molybdenum to be reduced beyond the desired extent.

Table B-32: Progression of Stannous Chloride Stain’s Approximate Time of Maximum Intensity during Shelf-Life Test for CCA-Treated Wood

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DISCUSSION OF SHELF-LIFE Overall, it was determined that the stannous chloride stain’s reagents of stannous chloride and ammonium molybdate were stable for approximately six months without causing any huge deviation in color intensity or reaction time. The first month of the shelf-life test is going to be repeated because the largest variation of color intensity and reaction time occurred during this time period. These variations were most likely due to inconsistent mixing of the stannous chloride stain. It was only after the first month of the stannous chloride stain shelf-life test that it was realized that the stain must be allowed to stand for five minutes in order to prevent such large variations in reaction time and color intensity because of mixing inconsistency. New Reagents: • Ammonium Molybdate (made on November 16, 2005) • Stannous Chloride (made on November 16, 2005)

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Revised Stannous Chloride Stain Shelf Life Test – 0 Weeks (Repeated) DATE OF EXPERIMENT: November 17, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA, 40 kg/m3 CCA,

ACZA SAWDUST OR SHREDDED WOOD: Untreated, 4.0 kg/m3 CCA, and 40 kg/m3 CCA shredded

wood; Borate, ACQ, CBA, and ACZA sawdust MIXING TIME: Approx. 5 minutes

Trial Wood Type Time 1 2 3 Stop nc nc nc Untreated Noticeable nc nc nc Stop nc nc nc Borate Noticeable nc nc nc Stop nc nc nc ACQ Noticeable nc nc nc Stop nc nc nc CBA Noticeable nc nc nc Stop 11:39 11:21 11:02 CCA, 4.0 kg/m3 Noticeable 19:39 19:21 19:02 Stop 08:46 08:29 08:12 CCA, 40 kg/m3

Noticeable 08:46 08:29 08:12 Stop 07:50 07:24 06:59 ACZA Noticeable 07:50 07:24 06:59

NOTE: mm:ss nc = no change n/a = not available Table B-33: Reaction Time – 0 Weeks (Repeated)

APPROXIMATE TIME OF MAXIMUM COLOR INTENSITY: 5 hours (CCA-treated wood );

2 hours (ACZA-treated wood) DISCUSSION: The reaction time and color intensity for the samples were consistent with what was seen in previous experiments. CCA-treated wood developed an intense blue color and reached its maximum color intensity in approximately five hours. ACZA-treated wood did not develop an intense blue color, but it did reach its maximum color intensity of a light blue in approximately two hours.

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Revised Stannous Chloride Stain Shelf Life Test – 2 Weeks (Repeated) DATE OF EXPERIMENT: December 1, 2005 TYPES OF WOOD TESTED: Untreated, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: All shredded wood samples MIXING TIME: Approx. 5 minutes


NOTE: mm:ss nc = no change Table B-34: Reaction Time – 2 Weeks (Repeated)


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Revised Stannous Chloride Stain Shelf Life Test – 4 Weeks (Repeated) DATE OF EXPERIMENT: December 15, 2005 TYPES OF WOOD TESTED: Untreated, Borate, ACQ, CBA, 4.0 kg/m3 CCA SAWDUST OR SHREDDED WOOD: Untreated and 4.0 kg/m3 CCA shredded wood; Borate,

ACQ, and CBA sawdust MIXING TIME: Approx. 5 minutes


NOTE: mm:ss nc = no change Table B-35: Reaction Time – 4 Weeks (Repeated)


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Revised Stannous Chloride Stain Shelf Life Test – Overall (Including Repeated 0-4 Weeks)

Time Trial 1 Trial 2 Trial 3 AVERAGE Weeks

Stop Noticeable Stop Noticeable Stop Noticeable Stop Noticeable *0 11:39 19:39 11:21 19:21 11:02 19:02 11:21 19:21 *2 16:01 29:30 15:51 29:11 16:08 29:08 17:04 30:20 *4 14:52 29:25 14:40 29:15 14:36 29:08 14:43 29:16 6 07:29 30:59 07:06 30:46 06:44 30:06 07:06 30:37 8 14:21 32:25 14:02 32:06 13:40 31:44 14:01 32:15 10 14:04 41:02 13:45 40:43 13:25 40:23 13:45 40:43 12 13:44 44:34 14:54 42:20 14:32 40:27 14:23 42:27 14 24:26 44:26 23:44 43:44 23:56 42:56 24:02 43:42 16 13:30 35:00 12:51 34:48 12:39 34:21 13:00 34:43 18 18:31 44:49 17:12 43:30 16:39 42:57 17:27 43:45 20 15:40 33:44 15:20 36:29 14:55 36:05 15:18 35:26 22 16:13 34:05 15:51 33:43 15:34 33:26 15:53 33:44 24 13:39 17:39 13:18 17:18 13:01 17:01 13:19 17:19 26 09:40 20:30 09:25 20:15 09:10 20:00 09:25 20:15

NOTE: mm:ss n/a = not available *Experiment week repeated Table B-36: Progression of Stannous Chloride Stain Reaction Time with 4.0 kg/m3 CCA-

Treated Wood during Shelf-Life Test (Including Repeated 0-4 Weeks)

Weeks Approx. Time of Max. Intensity (hours)

*0 5 *2 5 *4 5 6 4 8 5 10 5 12 5 14 5 16 5 18 5 20 5.25 22 5 24 5 26 5

NOTE: *Experiment week repeated Table B-37: Progression of Stannous Chloride Stain’s Approximate Time of Maximum Intensity

during Shelf-Life Test for CCA-Treated Wood (Including Repeated 0-4 Weeks)

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APPENDIX C

Laboratory Reports for Other Applications of the Stannous Chloride Stain

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Wipe Samples with Stannous Chloride Stain Dissolution Method (New Wood) DATE OF EXPERIMENT: May 15, 2005 PURPOSE This experiment was intended to determine if the stannous chloride stain dissolution method may also be used on synthetic wipe samples to identify the presence of arsenic. If the stain was able to differentiate synthetic wipes used on untreated wood and CCA-treated wood, it may be another way the stain may be used. The synthetic wipe was meant to simulate the amount of CCA preservative that may rub off on a human hand when coming into physical contact with CCA-treated wood, such as on playgrounds. In many cases, CCA-treated wood is still used in areas where human contact is frequent; however, some CCA-treated wood structures often have a coating that reduces the amount of CCA preservative that leaches out of the wood and/or rubs off on a human hand. A previous study on CCA-treated wood using synthetic wipes performed by Tomoyuki Shibata, 2005, estimated that approximately 100 µg of arsenic from 4.0 kg/m3 CCA-treated wood was collected per 100 cm2 of synthetic wipe. This estimated arsenic concentration was much lower than the arsenic concentration in sawdust or shredded wood; therefore, the effectiveness of the stain was a large concern. There may not be enough arsenic collected on the wipe in order to be detected by the stain because the intensity of blue color that develops is directly related to the concentration of arsenate. If the stain did not develop a blue color with a CCA exposed wipe, then it must be below the stain’s minimum detection limit (MDL), which will be determined later. If this was the case, then the stain may provide a very general approximation, at best. PROCEDURE • The “Standard Method for Synthetic Wipe on CCA-Treated Wood” (Shibata et al. 2005 and

U.S. CPSC 2003) was used on untreated and 4.0 kg/m3 CCA-treated wood; 3 trials were performed for each type of wood and 3 blank wipes were maintained. o Apparatus

Piece (12 x 12 cm) of dry polyester cloth (Static Neutralizing Cloth, AccTecg, VWR International catalog # TWTX350A).

Sampling device (a 1.1 kg, 8 cm diameter vinyl coated disk (50 cm2) with strings for pulling the device.

o Sample collection The bottom of the sampling device was covered with parafilm in order to avoid cross

contamination and a polyester wipe was placed over the parafilm and the wipe was attached with a rubber band.

A surface area (50 cm x 8 cm) was measured out on the horizontal surface, the area was marked with tape, and the sampling device was moved over the area by pulling the string back and forth 5 times and turning 90º and pulling another 5 strokes (total 10 strokes, 10 back and 10 forth).

The wipe was removed from the sampling device. • Being careful not to touch the sample site, a small border (0.5 to 1 cm) was cut around the

site. The cut-out contained the sample site and was, likewise, be a circle; the remaining wipe was discarded.

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• The cut-out was folded in half with the sample site being on the inside, and placed into a pre-labeled Ziploc bag.

• The wipes were tested using the Dissolution Method. o 10 mL distilled water were added to a 20-mL sample vial. o 9 drops of combined stannous chloride stain were added to the vial.

The combined stannous chloride stain was 8 parts of ammonium molybdate reagent added to 1 part stannous chloride reagent, mixed, and let stand for 5 minutes.

o The wipe was removed from the Ziploc bag and unfolded. o The wipe was placed at the bottom of the sample vial making sure to have the side of the

wipe containing the sample site on the outside as much as possible. • The stop time, noticeable time, and approximate time of maximum intensity was noted.




DATA

Trial Type of Wood Time 1 2 3 Stop nc nc nc Blank Noticeable nc nc nc Stop nc nc nc Untreated Noticeable nc nc nc Stop 14:47 14:12 16:46 4.0 kg/m3 CCA Noticeable 33:35 33:00 32:30

NOTE: mm:ss; nc = no change; the same sample site was wiped repeatedly during trials

Table C-1: Reaction Time of Wipes (New Wood) Approximate time of maximum intensity: 1.5 hours CONCLUSION The stannous chloride stain dissolution method was able to identify CCA-treated wood from untreated wood; neither the blank or untreated wood wipe sample reacted to the stannous chloride stain. The only minor setback was that the white color of the sample wipe made the developing blue color appear lighter. However, it should be considered that the wipes were performed on new wood. Less CCA preservative rubs off when the CCA-treated wood has been used, weathered, or in-service for an extended period of time. Consequently, a sample wipe of used, weathered, or in-service CCA-treated wood may not have a high enough concentration of arsenic to be detected by the stain. Another experiment should be performed that will test the stain’s effectiveness on used, weathered, or in-service untreated and CCA-treated wood.

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Wipe Samples with Stannous Chloride Stain Dissolution Method (Used Wood) DATE OF EXPERIMENT: June 8, 2005 PURPOSE This experiment was performed to determine if the stannous chloride stain dissolution method may also be used on synthetic wipe samples to determine the presence of arsenic. If the stain was able to differentiate synthetic wipes used on untreated wood and CCA-treated wood, it may be another way the stain may be used. This experiment had the same purpose as the previous experiment involving wipes, “Wipe Samples with Stannous Chloride Stain Dissolution Method (New Wood),” except the samples were collected from used untreated and CCA-treated wood. The samples were collected from two untreated, two 4.0 kg/m3 CCA-treated, and two 40 kg/m3 CCA-treated dimensional wood pieces; all the dimensional wood pieces were used in a previous study by Tomoyuki Shibata. The wood was set-up on a table behind the McArthur Engineering Building at the University of Miami and has been exposed to the natural elements for about 2.5 years. PROCEDURE • Use the “Standard Method for Synthetic Wipe on CCA-Treated Wood” (Shibata et al. 2005

and U.S. CPSC 2003) on each piece of dimensional wood (both pieces of untreated, 4.0 kg/m3 CCA-treated, and 40 kg/m3 CCA-treated wood). o Apparatus

Piece (12 x 12 cm) of dry polyester cloth (Static Neutralizing Cloth, AccTecg, VWR International catalog # TWTX350A).

Sampling device (a 1.1 kg, 8 cm diameter vinyl coated disk (50 cm2) with strings for pulling the device.

o Sample collection Cover the bottom of the sampling device with parafilm in order to avoid cross

contamination and place a polyester wipe over the parafilm and attach the wipe with a rubber band.

Measure the surface area (50 cm x 8 cm) on the horizontal surface, mark the area with tape, and move the sampling device on the area by pulling the string back and forth 5 times and turning 90º and pulling another 5 strokes (total 10 strokes, 10 back and 10 forth).

Remove the wipe from the sampling device. • Being careful not to touch the sample site, cut around the site leaving a small border (0.5 to 1

cm). The cut-out contains the sample site and should, likewise, be a circle; the remaining wipe may be discarded.

• Fold the cut-out in half with the sample site being on the inside, and place it into a pre-labeled Ziploc bag.

• Test the wipes using the Dissolution Method. o Add 10 mL distilled water to a 20-mL sample vial. o Add 9 drops of combined stannous chloride stain to the vial.

The combined stannous chloride stain is 8 parts of ammonium molybdate reagent added to 1 part stannous chloride reagent; mix and let stand for 5 minutes.

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o Remove the wipe from the Ziploc bag and unfold it. o Put the wipe at the bottom of the sample vial making sure to have the side of the wipe

containing the sample site on the outside as much as possible. • Note the stop time, noticeable time, and approximate time of maximum intensity. DATA

Time Type of Wood Stop Noticeable A nc nc Untreated B nc nc A 24:00:00 nc 4.0 kg/m3 CCA B 24:00:00 nc A 01:31:59 02:30:00 40 kg/m3 CCA B 01:31:34 02:30:00


Table C-2: Reaction Time of Wipes (Used Wood) Approximate time of maximum intensity: 48 hours CONCLUSION Although the stannous chloride stain dissolution method worked for wipe samples on new wood, it did not work well for used wood. The reaction time increased and the 4.0 kg/m3 CCA-treated wood wipe did not develop a blue color that is obvious to the untrained eye. This indicated that there was not enough arsenic on the wipe to cause a distinction to be made between untreated and 4.0 kg/m3 CCA-treated wood. Because the 4.0 kg/m3 CCA-treated wood wipe sample did not react well with the stain, it was assumed that it was because the arsenic concentration was below the stain’s MDL to cause a considerable blue color.

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Wipe Samples with Stannous Chloride Stain Dissolution Method (Used Wood) DATE OF EXPERIMENT: August 13, 2005 PURPOSE This experiment was intended to determine if the stannous chloride stain dissolution method may also be used on synthetic wipe samples to determine the presence of arsenic. If the stain was able to differentiate synthetic wipes used on untreated wood and CCA-treated wood, it may be another way the stain may be used. This experiment had the same purpose as the previous experiment involving wipes, except the samples were collected from used untreated and CCA-treated wood. The samples were collected from two untreated, two 4.0 kg/m3 CCA-treated, and two 40 kg/m3 CCA-treated dimensional wood pieces; all the dimensional wood pieces were used in a previous study by Tomoyuki Shibata. The wood was set-up on a table behind the McArthur Engineering Building at the University of Miami and has been exposed to the natural elements for about 2.5 years. PROCEDURE • With a piece of dry polyester cloth (12 x 12 cm; Static Neutralizing Cloth, AccTecg. VWR

International catalog #TWTX350A), the “cleanest” area of the wood was wiped to collect the wipe sample. The wood was repeatedly wiped in the direction of the grain. This prevented splintering of the wood or shredding of the wipe.

• Being careful not to touch the sample site, the site was cut out leaving a small border (0.5 to 1 cm). The remaining wipe was discarded.


• The wipes were tested using the Dissolution Method. o 10 mL distilled water was added to a 20-mL sample vial. o 9 drops of combined stannous chloride stain was added to the vial.


o The wipe was removed from the Ziploc bag and unfolded. o The wipe was placed at the bottom of the sample vial making sure to have the side of the





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DATA

Time Type of Wood Stop Noticeable A nc nc Untreated B nc nc A 03:00:00 03:00:00 4.0 kg/m3 CCA B 00:51:10 03:00:00 A 00:38:16 00:50:31 40 kg/m3 CCA B 00:37:32 00:49:47


Table C-3: Reaction Time of Wipes (Used Wood) Approximate time of maximum intensity: 48 hours CONCLUSION The stannous chloride stain dissolution method was able to identify CCA-treated wood from wipe samples using a different wiping method, which attempts to collect as much of the sample on the wipe. The 4.0 kg/m3 CCA-treated wood wipe sample developed a noticeable blue color in approximately three hours and developed its maximum blue color intensity in about 48 hours.

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Wipe Samples with Stannous Chloride Stain Dissolution Method (New ACZA-Treated Wood)

DATE OF EXPERIMENT: November 17, 2005 PURPOSE This experiment was intended to determine if the stannous chloride stain dissolution method may also be used on synthetic wipe samples to determine the presence of arsenic. If the stain was able to differentiate synthetic wipes used on untreated wood and arsenic-treated wood, it may be another way the stain may be used. This experiment had the same purpose as the previous experiment involving wipes, except the samples were collected from new ACZA-treated wood. PROCEDURE • With a piece of dry polyester cloth (12 x 12 cm; Static Neutralizing Cloth, AccTecg. VWR

International catalog #TWTX350A), the “cleanest” area of the wood was wiped to collect the wipe sample. The wood was repeatedly wiped in the direction of the grain. This prevented splintering of the wood or shredding of the wipe.

• Being careful not to touch the sample site, the site was cut out leaving a small border (0.5 to 1 cm). The remaining wipe was discarded.


• The wipes were tested using the Dissolution Method. o 10 mL distilled water were added to a 20-mL sample vial. o 9 drops of combined stannous chloride stain was added to the vial.


o The wipe was removed from the Ziploc bag and unfold it. o The wipe was placed at the bottom of the sample vial making sure to have the side of the





DATA

Trial Type of Wood Time 1 2 Stop 06:13 05:40 ACZA Noticeable 16:43 16:10

NOTE: mm:ss; the same sample site was wiped repeatedly during trials

Table C-4: Reaction Time of Wipes (New Wood)

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Approximate time of maximum intensity: 5 hours CONCLUSION The stannous chloride stain dissolution method developed an intense blue color with wipe samples collected from new ACZA-treated wood in approximately five hours. This was interesting when comparing these results with wipe samples using the stannous chloride stain dissolution method than with shredded wood or sawdust samples. Shredded wood or sawdust samples of ACZA-treated wood did not develop an intense blue with the stain, only a light blue. However, the wipe samples collected from new ACZA-treated wood did develop an intense blue color similar to that witnessed with CCA-treated wood. This indicated that identifying ACZA-treated wood with the stannous chloride stain dissolution method using wipe samples would actually be better than using shredded wood or sawdust samples. Unfortunately, used ACZA-treated wood was unavailable and could not be tested.

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Dissolution Method for Ash DATE OF EXPERIMENT: May 27, 2005 PURPOSE This experiment was intended to determine if the stannous chloride stain dissolution method could be used to detect arsenic in ash, similar to how it was used to detect arsenic in sawdust or shredded wood. PROCEDURE • The Dissolution Method of the stannous chloride stain was applied to the following ash

samples: untreated, 4.0 kg/m3 CCA, 9.6 kg/m3 CCA, and 40 kg/m3 CCA-treated wood. o Due to volumetric limitations, only 0.25 g of CCA-treated wood ash at each

concentration was used as a sample. • The reaction time started when the ash was added to the solution. • The stop time was noted for all samples, defined as the time the sample solution begins to

change color. • Any additional observations were noted for all samples. DATA

Ash Type Reaction Time Observations

Untreated nc • Ash is brown; solution is colorless. • Bubbling occurred immediately upon addition of ash to the

stain solution.

4.0 kg/m3 CCA unknown • Ash is dark brown; solution is green. • The exact time at which the color change occurred is

unknown due to the heavy masking color of the ash itself.

9.6 kg/m3 CCA unknown • Ash is olive green; solution is light blue-green. • The exact time at which the color change occurred is

unknown due to the heavy masking color of the ash itself.

40 kg/m3 CCA unknown • Ash is olive green; solution is light blue-green. • The exact time at which the color change occurred is

unknown due to the heavy masking color of the ash itself. *NOTE: nc = no change

Table C-5: Reaction Time and Sample Observations CONCLUSION The stannous chloride stain dissolution method should not be used to determine the presence of arsenic in ash. The color of the ash itself was so intense as to mask the color of molybdenum blue. It was a possibility that once the ash settles, the molybdenum blue color may be visible as seen with the 9.6 kg/m3 and 40 kg/m3 CCA-treated wood ash samples, but it was not seen in the 4.0 kg/m3 CCA-treated wood ash sample and not very intense. In addition, it was unknown if the color of the solutions in the CCA-treated wood ash samples can be attributed exclusively to the formation of molybdenum blue. This researcher doubts the molybdenum blue color would be visible in other situations where the ash may be different colors. However, the bubbling that occurred upon addition of the untreated wood ash sample was interesting because none of the CCA-treated wood ash samples bubbled upon addition to the

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stain solution. The bubbling was most likely due to the pH difference between the ash and the solution, and the possibility that pH may be able to determine the difference between treated wood ash and untreated wood ash.

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Determination of pH for Ash and Stannous Chloride Stain Solution DATE OF EXPERIMENT: May 27, 2005 PURPOSE By determining the pH of ash for Untreated, 4.0 kg/m3 CCA, and 40 kg/m3 CCA-treated wood, it would be possible to establish the possibility that pH differences in ash could identify if it may be considered hazardous due to high levels of arsenic. PROCEDURE Stannous Chloride Stain • 8 parts ammonium molybdate reagent was added to 1 part stannous chloride reagent, mixed

and let stand for 5 minutes. • pH was determined. • 9 drops of the combined stain were added to 10 mL distilled water; pH was determined. Ash • 1 g of ash (Untreated, 4.0 kg/m3 CCA, 40 kg/m3 CCA) was added to 100 mL of distilled

water, and soaked for 20 minutes. • pH was determined. DATA

Description pH Combined Reagents <0 Stannous Chloride Stain + Water 1.203 Untreated Ash 11.917 4.0 kg/m3 CCA Ash 7.728 40 kg/m3 CCA Ash 6.118

Table C-6: pH for Stannous Chloride Stain and Ash CONCLUSION The data explained why bubbling occurred once ash from untreated wood was added to the stannous chloride stain (dissolution method). The stannous chloride stain was very acidic (pH=1.203), as opposed to untreated ash, which was more basic (pH=11.917). In addition, there was a very large difference in pH between ash from untreated and CCA-treated wood. Therefore, an acidic solution, such as the stannous chloride stain, could be used to determine if ash was from untreated or CCA-treated wood by the occurrence of bubbles. In addition, pH paper and other reasonable pH indicators, such as phenolphthalein that turns from colorless to bright pink around a pH of 9.3, may likewise succeed. However, this did not consider ash resulting from mixtures of untreated and CCA-treated wood. If the pH does not change dramatically with increasing amounts of CCA-treated wood in the mixture, then it would not be rational to use pH as an indicator for the presence of arsenic in mixtures.

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Determination of pH for Ash and Stannous Chloride Stain Solution DATE OF EXPERIMENT: June 5, 2005 PURPOSE By determining the pH of ash samples of mulch from a previous study (Solo-Gabriele, Townsend, Jacobi, et. al., 2005), it will be possible to establish the possibility that pH differences in ash could identify if it may be considered hazardous due to high levels of arsenic. Solo-Gabriele (1999) stated that wood mixtures that contained more than five percent CCA-treated wood would be considered hazardous and could not be used as fuel. A brief background into the chemical preservatives of alternative treated wood reveals that CCA-treated wood is treated with an acidic solution, while most other treated wood chemicals, such as ACQ, Borates, CBA, CC, and CDDC, are in a basic solution (Solo-Gabriele, Townsend, Kormienko, et. al., 2000). Chemical composition for AAC was unavailable, but it is assumed that alkyl ammonium compound is a basic solution. Chemical composition for ACC was also unavailable, but it is assumed that acid copper chromate is an acidic solution; however, the use of ACC-treated wood is mainly in the construction of cooling towers in Idaho. PROCEDURE • Add 1 g of ash (Untreated, 4.0 kg/m3 CCA, 40 kg/m3 CCA) to 100 mL of distilled water. • Let soak for 20 minutes; analyze pH. DATA Sample No.

(Solo-Gabriele,

Townsend, Jacobi, et. al., 2005)

Description (Solo-Gabriele, Townsend, Jacobi, et. al., 2005)

%CCA Range (Solo-

Gabriele, Townsend,

Jacobi, et. al., 2005)

Ave. %CCA pH

1 Red BB 0.03 10.378 6 Red 3.6 - 3.8 3.70 10.232 7 Red 3.5 - 5.0 4.25 10.274 10 Red, Open Bin 13.1 - 17.0 15.10 9.687 14 Red, Playground 4.8 - 5.7 5.25 9.657 22 No Color BB - 0.1 0.07 10.140 26 No Color 0.7 - 0.8 0.75 10.358 30 Control. 100% 4.0 kg/m3 CCA wood 61.2 - 64.9 63.10 7.045 34 No Color BB 0.03 10.732 * 5% 4.0 kg/m3 CCA/95% Untreated 5.0 5.00 10.862

** 5% 4.0 kg/m3 CCA/95% Untreated (by ash wt.) 5.0 5.00 11.845

*Sample “5% 4.0 kg/m3 CCA/95% Untreated” was not part of the samples studied by Solo-Gabriele, Townsend, Jacobi, et. al., 2005. This sample was, however, created in a similar fashion where the samples were mixed by weight of the wood. **Sample "5% 4.0 kg/m3 CCA/95% Untreated (by ash wt.)" was not part of the samples studied by Solo-Gabriele, Townsend, Jacobi, et. al., 2005. This sample was created by adding 0.05 g 4.0 kg/m3 CCA-treated wood ash to 0.95 g untreated wood ash. BB = Below Baseline (approx. 0.03%)

Table C-7: pH and Percent CCA of Mulch Ash Samples

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6

7

8

9

10

11

12

0 5 10 15 20 25 30 35 40 45 50 55 60 65

Average Percent CCA

pH

5

Figure C-1: Graph of pH vs. Average Percent CCA

9

9.5

10

10.5

11

11.5

12

0 2 4 6 8 10 12 14 16Average Percent CCA

pH

5

Figure C-2: Area of Interest – Graph of pH vs. Average Percent CCA

CONCLUSION The pH value of an ash sample would not be valuable towards determining if the ash is hazardous and contains arsenic. There was a significant pH difference of 2.642 between sample #10 (average 15.10% CCA) and sample #30 (average 63.10% CCA); however, as the average percent CCA decreases to the critical point of 5% CCA, the pH difference was practically unnoticeable. The difference between the sample #14 (average 5.25% CCA) and sample #22 (average 0.07% CCA) was only 0.483 pH. Therefore, pH was not dependent on the percentage of CCA composition in ash.

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APPENDIX D

Laboratory Reports for Other Potential Arsenic-Specific Stain Formulas

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Vanadomolybdophosphoric Acid Method – Heating Phosphate Samples DATE OF EXPERIMENT: November 14, 2004 PURPOSE This experiment was performed to determine if the yellow color that was expected from vanadomolybdophosphoric acid would dissipate when heated. ADDITIONAL REAGENTS • 0.05 mg/L P solution • 1.0 mg/L P solution PROCEDURE • 35 mL or less of sample (blank, 0.05 mg/L P, 1.0 mg/L P) were placed in 50-mL volumetric

flask. • 10 mL vanadate-molybdate reagent was added. • The solution was diluted to the mark with distilled water, and mixed. • The initial color and color intensity were recorded. • After 10 minutes, any changes in color and color intensity were recorded. • The samples were heated in a water bath for 30 minutes. • Any changes in color and color intensity were recorded. DATA

Time (min) Blank 0.05 mg/L P 1.0 mg/L P 0 faint yellow light yellow intense yellow 10 no change no change no change

30 (heated) no change no change no change Table D-1: Color and Color Intensity of Phosphate Samples

Figure D-1: Picture of Phosphate Samples, Initial

Blank 0.05 mg/L P 1.0 mg/L P

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Figure D-2: Picture of Phosphate Samples, 10 Minutes

Figure D-3: Picture of Phosphate Samples, Heated in Water Bath for 30 Minutes

CONCLUSION From this experiment, it appeared that heating did not have a significant effect on changing the color of phosphate samples. In addition, it did not take the advised time of 10 minutes for full color intensity to be reached, as can be seen from the almost no difference in color change from start time to 10 minutes. Therefore, the results from this experiment did not maintain a good outlook on using the vanadomolybdophosphoric acid method to identify samples containing arsenate. The yellow color achieved in the detection of phosphate did not disappear, hence it was almost impossible to determine if any yellow color achieved in the detection of arsenate was caused by the presence of arsenate or phosphate.

Blank

Blank

0.05 mg/L P

0.05 mg/L P

1.0 mg/L P

1.0 mg/L P

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Vanadomolybdophosphoric Acid Method – Dissolution Method and Heating DATE OF EXPERIMENT: November 14, 2004 PURPOSE This experiment was performed to determine the effects of the vanadomolybdophosphoric acid colorimetric method on samples containing Untreated, ACQ, and 4.0 kg/m3 CCA-treated shredded wood or sawdust in solution (Dissolution Method). PROCEDURE • 0.5 g of shredded wood or sawdust (Untreated, ACQ, and 4.0 kg/m3 CCA-treated) was

measured into a sample vial. • 16 mL distilled water was added. One blank was prepared with 16 mL distilled water. • 4 ml vanadate-molybdate reagent was added, and mixed. • The initial color and color intensity were recorded. • After 10 minutes, any changes in color and color intensity were recorded. • The samples were heated in a water bath for 30 minutes. • Any changes in color and color intensity were recorded. DATA

Time (min) Blank Untreated ACQ 4.0 kg/m3 CCA 0 faint yellow faint yellow faint yellow faint yellow

10 no change no change no change no change 30 (heated) no change faint gray no change faint gray-blue

Table D-2: Color and Color Intensity of Dissolution Samples

Figure D-4: Picture of Dissolution Samples, 10 Minutes

Figure D-5: Picture of Dissolution Samples, Heated in Water Bath for 30 Minutes

Blank

Blank

Untreated

Untreated ACQ

ACQ CCA

CCA

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CONCLUSION This experiment was unsuccessful for the previously stated purpose; however, it did create some curiosity that could be looked into further. There was no visible yellow color present due to vanadomolybdophosphoric acid. Any faint yellow color observed could have been from the color of the actual wood; the discoloration of the solution for ACQ was most likely due to some solids suspended in the solution because ACQ sawdust instead of shredded wood was used for that sample. The lack of yellow color in solution was confusing because it was known that phosphate was present in all the samples and arsenate was also present in CCA. Even more interesting was the development of a faint gray and gray-blue color in the Untreated and CCA-treated wood samples, respectively, after heating in a water bath. If this experiment were repeated, it is advised that the samples be run in duplicate and monitored for a longer period of time (24 to 48 hours). In addition, the possibility that heating the samples prior to the addition of vanadate-molybdate reagent may lead to better results may be included.

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Vanadomolybdophosphoric Acid Method – Filtrate Dissolution Method and Heating DATE OF EXPERIMENT: November 14, 2004 PURPOSE This experiment was intended to determine if any color observed during the “Dissolution Method and Heating” experiment was due to the color of the wood or an actual reaction with the vanadate-molybdate reagent. By filtering the samples, thus removing the solid wood, the color of the filtrate and any subsequent color changes may be observed more clearly. PROCEDURE • 1.0 g of shredded wood or sawdust (Untreated, ACQ, and 4.0 kg/m3 CCA-treated) was

measured into a beaker. • 30 mL distilled water was added, and mixed. • The wood was soaked for 30 minutes, mixing occasionally. • The wood was removed from the sample by filtration. • 16 mL of sample filtrate were put into a sample vial. • 4 ml vanadate-molybdate reagent were added, and mixed. • The initial color and color intensity were recorded. • After 10 minutes, any changes in color and color intensity were recorded. • The samples were heated in a water bath for 30 minutes. • Any changes in color and color intensity were recorded. DATA

Time (min) Untreated ACQ 4.0 kg/m3 CCA 0 colorless faint yellow colorless 10 no change no change no change

30 (heated) no change no change no change Table D-3: Color and Color Intensity of Filtrate Samples

Figure D-6: Picture of Filtrate Samples, Initial

Untreated ACQ CCA

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Figure D-7: Picture of Filtrate Samples, 10 Minutes

Figure D-8: Picture of Filtrate Samples, Heated in Water Bath for 30 Minutes

CONCLUSION The results from this experiment showed that there was no color change in solution, and most of the color seen in the previous experiment, “Dissolution Method and Heating,” was due to the color of the wood. The faint yellow color observed in the ACQ sample was still most likely due to suspended solids in the solution because ACQ sawdust was used instead of shredded wood. The faint gray or gray-blue color observed previously after heating the samples in a water bath was not replicated in this experiment. If this experiment were repeated, it is advised that the samples be run in duplicate and monitored for a longer period of time (24 to 48 hours). In addition, the possibility that heating the samples prior to the addition of vanadate-molybdate reagent may lead to better results may be included, and an analysis of the presence of phosphate and/or arsenate in the filtrate may need to be confirmed.

Untreated

Untreated ACQ

ACQ CCA

CCA

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Vanadomolybdophosphoric Acid Method – Whole Wood Application DATE OF EXPERIMENT: November 16, 2004 PURPOSE This experiment was performed to determine the effects of the vanadomolybdophosphoric acid colorimetric method on whole wood samples of Untreated, ACQ, and 4.0 kg/m3 CCA-treated (Whole Wood Application). Another factor taken into consideration was which face of the wood, transverse or radial, was the best surface to apply the stain, vanadate-molybdate reagent. PROCEDURE • 3 drops of vanadate-molybdate reagent were applied to the transverse or radial face of each

piece of wood (Untreated, ACQ, and 4.0 kg/m3 CCA-treated). • Any initial change in color and color intensity at stain application site were recorded. • Any changes in color and color intensity at stain application site were recorded for time 10,

30, and 60 minutes. DATA

Untreated ACQ 4.0 kg/m3 CCA Time (min) Radial Transverse Radial Transverse Radial Transverse 0 nc nc nc nc nc nc 10 nc nc nc nc nc nc 30 nc nc nc nc nc nc 60 nc nc nc nc nc nc

*nc = no change Table D-4: Change in Color and Color Intensity of Whole Wood Samples

Figure D-9: Picture of Whole Wood Samples, Initial

Untreated ACQ CCA

Radial

Transverse

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Figure D-10: Picture of Whole Wood Samples, 10 Minutes



CONCLUSION The results from this experiment showed that there was no color change on whole wood application in the experimental time period (60 minutes). However, after 24 hours, there was a CCA-treated wood did react with the vanadate-molybdate reagent and a blue color developed on the stain application sites of both the radial and transverse face of CCA wood. For now, it was unknown as to when the vanadate-molybdate reagent caused CCA to turn blue or why. In addition, the untreated wood also turned blue at the stain application sites at a later time (>24

Untreated

Untreated

Untreated ACQ

ACQ

ACQ

CCA

CCA

CCA

Radial

Radial

Radial

Transverse

Transverse

Transverse

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hours). A positive for phosphate with the vanadate-molybdate reagent should result in a yellow color due to the vanadomolybdophosphoric acid, which was also expected to indicate a positive for arsenate. However, it was a possibility that the molybdenum blue color that resulted after 24 hours may have overtaken the expected yellow color or that the yellow color never appeared. Further experimentation and research could be performed to investigate why molybdenum blue appeared in the vanadomolybdophosphoric acid colorimetric method, and the experiment should be reproduced and monitored for a longer time period (48 to 72 hours). The blue color that appeared in this experiment may be a clue as to why the gray and gray-blue color appeared in the previous “Dissolution Method and Heating” experiment.

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Ascorbic Acid Method – Dissolution Method DATE OF EXPERIMENT: December 31, 2004 PURPOSE This experiment was intended to determine the possibility of using an ascorbic acid stain to identify CCA-treated wood. Previous experiments conducted in 2000 by Michael Laas, a University of Miami student, have shown a tendency for ascorbic acid to give a positive result with untreated wood. Ascorbic acid will be used to identify CCA-treated wood using the dissolution method. In addition, this experiment would determine if it was better to soak the wood in water and then introducing ascorbic acid to the sample. PROCEDURE • 6 20-mL sample vials were filled with 10 mL distilled water. • 0.5 g of untreated wood was added to a sample vial, and 4.0 kg/m3 CCA-treated wood was

added another vial, mixed, and let soak for 30 minutes, mixing occasionally. o After 30 minutes, 1.6 mL ascorbic acid was added, and mixed. The reaction time started

upon addition of ascorbic acid, and stopped when the color of the solution began to change, mixed occasionally.

• To the remaining 4 sample vials, 1.6 mL ascorbic acid was added. o 0.5 g of untreated wood was added to two sample vials, and mixed. The reaction time

started upon addition of the wood to the solution, and stopped when the color of the solution began to change, mixed occasionally.

o 0.5 g of 4.0 kg/m3 CCA-treated wood was added to two sample vials, and mixed. The reaction time started upon addition of the wood to the solution, and stopped when the color of the solution began to change, mixed occasionally.

• The reaction time, color, and color intensity were noted. o The stop time was defined as the time the sample solution begins to change color, or

when a faint to light blue color appeared o The noticeable time was defined as the time the color of the sample solution appeared

light to medium blue. o The approximate time of maximum intensity was defined as the time the color intensity

reached a maximum and started to decrease. DATA

Untreated 4.0 kg/m3 CCA Time A B Soak A B Soak

Stop 01:22 01:32 00:38 04:14 04:02 03:44

Noticeable 01:50 02:04 00:53 05:59 05:54 04:34

Intense 08:00 (intense blue)

07:39 (intense blue)





Fade 15:00 (gray)

14:39 (gray)

11:57 (gray) -- -- --

NOTE: mm:ss

Table D-5: Reaction Time and Description of Samples

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CONCLUSION This experiment showed that ascorbic acid had an initial positive result for all wood samples of untreated and 4.0 kg/m3 CCA-treated wood. In this aspect, it was unable to differentiate between untreated and CCA-treated wood; however, only the untreated wood samples faded to a gray color, while the CCA samples maintained the intense blue color. Using ascorbic acid to identify CCA-treated wood was, therefore, possible, but the description of the differences in color development would have to very detailed. More testing could be done to confirm that using an ascorbic acid stain by the dissolution method has results consistent with this experiment, and the samples should be monitored for a longer period of time to ensure that the color difference between untreated and CCA-treated wood continued to be noticeable. Because the intense blue color achieved in untreated wood will fade to a gray color, the intense blue color achieved in CCA-treated wood should be stable for an extended period of time.

APPENDIX A Laboratory Reports for the Development of a Chemical

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