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Dr. Richard ReissDr. Richard Reiss

Sciences International, Inc.Sciences International, Inc.

October 20, 2005October 20, 2005

Environmental Safety of Active Environmental Safety of Active Pharmaceutical IngredientsPharmaceutical Ingredients

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IntroductionIntroduction

• Talk will focus on triclosan (TCS) and Talk will focus on triclosan (TCS) and triclocarban (TCC)triclocarban (TCC)

• For each chemical, I will provide:For each chemical, I will provide:– General environmental fate characteristicsGeneral environmental fate characteristics– Representative environmental concentration dataRepresentative environmental concentration data– Toxicity levels of most sensitive speciesToxicity levels of most sensitive species– Comparison of concentrations and toxicity levelsComparison of concentrations and toxicity levels

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General Environmental General Environmental Fate PropertiesFate Properties

• Both compounds have similar fate properties:Both compounds have similar fate properties:– Very low vapor pressuresVery low vapor pressures– Soluble in waterSoluble in water– Highly adsorbent to organic matterHighly adsorbent to organic matter

• Both compounds will reach the environment Both compounds will reach the environment through down-the-drain disposalthrough down-the-drain disposal

– Both show significant degradation in water treatment Both show significant degradation in water treatment plants (next slide)plants (next slide)

• TCS shows rapid removal from water column in TCS shows rapid removal from water column in die-away studies (2-5 hour half-life)die-away studies (2-5 hour half-life)

– Also, biodegrades in soil in 17-35 daysAlso, biodegrades in soil in 17-35 days• TCC shows rapid degradation in biosolids (10 TCC shows rapid degradation in biosolids (10

hour half-life)hour half-life)

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Average Removal Rates in Average Removal Rates in Wastewater Treatment PlantsWastewater Treatment Plants

ActivesActives Activated Activated SludgeSludge

Trickling Trickling FilterFilter

TCCTCC 94%94% 77%77%

TCSTCS 95%95% 83%83%

Predominant pathway is biodegradation

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Freshwater Aquatic Environmental Freshwater Aquatic Environmental Concentrations in U.S. for TCCConcentrations in U.S. for TCC

SourceSource ResultsResults

TCC TCC Consortium, Consortium,

20022002

•Max=0.23 ppb, 90% less than 0.05 ppbMax=0.23 ppb, 90% less than 0.05 ppb

Halden & Halden & Paull, 2005Paull, 2005

•Max=6.8 ppb in sites with significant Max=6.8 ppb in sites with significant raw sewageraw sewage

EPA E-FAST EPA E-FAST model, TCC model, TCC consortium, consortium,

20022002

•Model estimates, high-end at outfall = Model estimates, high-end at outfall = 0.017 ppb, median at outfall = 0.0013 0.017 ppb, median at outfall = 0.0013 ppbppb

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Freshwater Aquatic Environmental Freshwater Aquatic Environmental Concentrations in U.S. for TCSConcentrations in U.S. for TCS

SourceSource StudyStudy

USGS, 2002USGS, 2002 •7575thth Percentile = 0.2 ppb, median of Percentile = 0.2 ppb, median of measured conc =0.14 ppb. Sampling measured conc =0.14 ppb. Sampling locations chosen as “susceptible to locations chosen as “susceptible to contamination.”contamination.”

USGS, 2004USGS, 2004 • Non-detectable in typical flow conditions, Non-detectable in typical flow conditions, Max=0.14 ppb in low flow conditionsMax=0.14 ppb in low flow conditions

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Most Sensitive Aquatic SpeciesMost Sensitive Aquatic Species

ActivesActives Chronic Toxicity and No Observed Effect Chronic Toxicity and No Observed Effect Concentrations (NOECs)Concentrations (NOECs)

TCCTCC Waterflea, Waterflea, Ceriodaphnia dubiaCeriodaphnia dubia, NOEC = 1.5 , NOEC = 1.5 ppbppb

Algae, 6 ppb, minimum algistatic Algae, 6 ppb, minimum algistatic concentrationconcentration

TCSTCS Blue-green algae, NOEC = 0.5 ppb Blue-green algae, NOEC = 0.5 ppb (algistatic, (algistatic, notnot algicidal, algicidal, recoveryrecovery in 3-6 in 3-6 days)days)

Waterflea, Waterflea, Ceriodaphnia dubiaCeriodaphnia dubia, NOEC=6 , NOEC=6 ppbppb

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Comparison of Environmental Comparison of Environmental Concentrations to NOECs for TCCConcentrations to NOECs for TCC

1.50

0.23

0.05 0.017 0.00130

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

NOEC Max Measured 90% Measured High-End EPAModel

Median EPAModel

Co

nce

ntr

atio

n (

pp

b)

TCC ConsortiumMeasurements

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Comparison of Environmental Comparison of Environmental Concentrations to NOECs for TCSConcentrations to NOECs for TCS

0.50

6.00

0.20 0.14 0.14

0

1

2

3

4

5

6

7

NOEC, algae NOEC,invertebrates

75th% (2002) Median (2002) Max, Low Flow(2004)

Co

nce

ntr

atio

n (

pp

b)

USGS Measurements

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Terrestrial RiskTerrestrial Risk

• Both TCS and TCC can be present in sewage Both TCS and TCC can be present in sewage sludge in small concentrationssludge in small concentrations– Sludge may be used as soil amendments in Sludge may be used as soil amendments in

agricultureagriculture– Low potential of exposure to ecological speciesLow potential of exposure to ecological species

• Due to low mammalian toxicity, low sludge Due to low mammalian toxicity, low sludge concentrations, and low potential for concentrations, and low potential for exposure, risks to ecological species are exposure, risks to ecological species are expected to be minimal expected to be minimal (Federle et al., 2002)(Federle et al., 2002)

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ConclusionsConclusions

• The large majority of the TCC and TCS mass The large majority of the TCC and TCS mass will degrade in treatment plants, but some will degrade in treatment plants, but some will be present in effluent and sludgewill be present in effluent and sludge– Neither is expected to persist in the environmentNeither is expected to persist in the environment

• TCC shows low risk to aquatic species when TCC shows low risk to aquatic species when high-end concentrations are compared to the high-end concentrations are compared to the no effect level for the most sensitive speciesno effect level for the most sensitive species

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Conclusions (cont)Conclusions (cont)

• TCS may have transitory algistatic effects on TCS may have transitory algistatic effects on some algal species under worst case some algal species under worst case conditions and only in aquatic environments conditions and only in aquatic environments close to the effluent pipeclose to the effluent pipe– Downstream effects are not expectedDownstream effects are not expected

• TCS is unlikely to have any significant TCS is unlikely to have any significant effects on non-algal specieseffects on non-algal species