Post on 29-Jan-2016
Year “7” and Year “8” Studies Focusing on Mulch
• Early research has shown that mulches made from recycled dimensional wood can be contaminated with CCA (Townsend et al. 2003).
• Follow-up study -> Year 7 – South Florida – mulches from stores
Year 8 – Rest of Florida – mulches from stores Study to evaluate impact of colorants
Mulch – Buffer Materials
Gary’s Focus Shiba’s Focus
Playground Mulch
Mulch made from C&D Wood
Mulch Analysis Methods
Sample
Visual Inspection
Size Distribution
Ash for Total Metals
SPLP Analysis
Chemical Analysis
Physical Analysis
Visual Inspection
Objects Found in Mulch
Nails Plastic Rubber Glass String Rocks Etc.
Size Distribution
Uniformity Coefficient (UC): The UC will approach 1 if the pieces of sample
are the same size
d50: The size in inches that 50% of the sample is finer than
UC d60
d10
Sieve Analysis
Results: Visual Inspection
52% are colored mulches
17% mulches contained plywood
73% mulches with plywood are colored
Results: Size Distribution
Average d50 of samples is 0.29 in.
Average Uniformity Coefficient is 5.0
D50 Histogram
5
37
49
46
0
10
20
30
40
50
60
0 - 0.1 0.1 - 0.2 0.2 - 0.5 0.5 - 1 1 - 1.5
D50 (in)
Fre
qu
en
cy (
%)
Fre
quen
cy %
Results: Size DistributionUniformity Coefficient
15
28
34
18
4
0
5
10
15
20
25
30
35
40
1 - 3 3 - 4 4 - 5 6 - 8 > 8
UC
Fre
quency (
%)
Chemical Analysis
Sample
Visual Inspection
Size Distribution
Ash for Total Metals
SPLP Analysis
Chemical Analysis
Physical Analysis
Analysis Procedure Total MetalsResults
LeachableResults
Methods: Ash for Total Metals
Ashed Samples: 58
30
20 10 3 25
28
Results: Ash for Total Metals
As > 3.7 mg/kg
Colored Not Colored
As < 3.7 mg/kg As > 3.7 mg/kg As < 3.7 mg/kg
Colored Plywood
Number of
Samples
> 3.7 mg/kgArseni
c
> 10 mg/kg Arseni
c
> 50 mg/kg Arseni
c
> 100 mg/kg Arseni
c
25 12 % 12 % 4 % 0 %
√ 20 15 % 15 % 5 % 0 %
√ 3 0 % 0 % 0 % 0 %
√ √ 10 70 % 70 % 70 % 30 %
Open Bin 3 67 % 67 % 67 % 67 %
Pine Bark 27 7 % 7 % 4 % 0 %
Results: Ash for Total Metals
Metals in Wood (South Florida)
0.01
0.10
1.00
10.00
100.00
1000.00
10000.00
11 15 32 12 13 14 26 1 4 6 7 10 2 3 5 24 8 9 17 18 19 20 22 23 25 16 21 28 30 31
Sample
Co
nce
ntr
atio
n (
mg
/kg
)
AsCuCr
Pla
ygro
und
No
Col
or
No
Ply
woo
d
Woo
d S
oil B
lend
RD
F F
ine
Soi
l
RD
F
Res
ide
ntia
l, no
co
lor,
no
plyw
ood
Out
of
Sta
te
Pla
ygro
und
No
Col
or
No
Ply
woo
d
No
Col
or
No
Ply
woo
d
Col
ored
No
Ply
woo
d
Col
ored
Ply
woo
d
Pla
ygro
und
Col
ored
Ply
woo
d
0.25
pcf
Unt
rea
ted
Metals in Wood (Rest of Florida)
0.01
0.10
1.00
10.00
100.00
1000.00
81 89 91 45 34 35 78 33 41 42 44 48 50 52 54 55 56 57 59 60 61 63 64 65 67 69 71 72 76 84 86 92 94 43 46 47 49 51 53 58 62 66 68 70 36 73 74 75 77 79 80 82 83 85 87 88 90 93 95 96 97
Sample
Co
nce
ntr
atio
n (
mg
/kg
)
AsCuCr
Ply
woo
d
Col
ored
Ply
woo
d
No
Col
or
No
Ply
woo
d
Col
ored
No
Ply
woo
d
No
Col
or
Concentration Range of Arsenic Samples
80
60
95
0
10
20
30
40
50
60
70
80
90
0 - 10 11 - 25 26 - 50 51 - 100 > 100
Concentration Range (mg/kg)
Fre
qu
en
cy (
%)
Fre
quen
cy %
Arsenic vs. ChromiumAsh
0
10
20
30
40
50
60
70
80
90
100
0 50 100
Chromium (mg/ kg)
Ars
enic
(m
g/kg)
SPLP Results
Methods: SPLP Analysis
SPLP Samples: 86
45
29 16 7 34
41
Mulch SPLP Results
Positive for Arsenic
Colored Not Colored
Not Positive for Arsenic Positive for Arsenic Not Positive for Arsenic
SPLP Table
Colored Plywood
Number of
Samples
> 12 g/L
Arsenic
> 50 g/L
Arsenic
> 100 g/L
Arsenic
37 16 % 5 % 3 %
√ 34 21 % 3 % 3 %
√ 4 25 % 0 % 0 %
√ √ 11 82 % 73 % 45 %
Open Bin 4 75 % 75 % 50 %
Pine Bark 45 22 % 4 % 0 %
SPLP (South Florida)
1
10
100
1000
10000
11 15 32 12 13 14 26 1 4 6 7 10 2 3 5 24 8 9 17 18 19 20 22 23 25 16 21 28 30 31
Sample
Co
nce
ntr
atio
n (
mg
/kg
)
AsCuCr
Pla
ygro
und
No
Col
or
No
Ply
woo
d
Woo
d S
oil B
lend
RD
F F
ine
Soi
l
RD
F
Res
ide
ntia
l, no
co
lor,
no
plyw
ood
Out
of
Sta
te
Pla
ygro
und
No
Col
or
No
Ply
woo
d
No
Col
or
No
Ply
woo
d
Col
ored
No
Ply
woo
d
Col
ored
Ply
woo
d
Pla
ygro
und
Col
ored
Ply
woo
d
0.25
pcf
Unt
rea
ted
Concentration Range of Arsenic Samples
76
12
05
8
0
10
20
30
40
50
60
70
80
0 - 12 13 - 25 26 - 50 51 - 100 100 - 200
Concentration Range (ug/L)
Fre
qu
en
cy (
%)
Fre
quen
cy %
SPLP
0
20
40
60
80
100
120
140
160
180
200
0 100 200 300 400 500 600
Chromium (ug/ L)
Ars
enic
(ug/L)
Arsenic vs. Chromium
Arsenic vs. Chromium
0
20
40
60
80
100
120
140
160
180
200
0 20 40 60 80 100 120 140
Chromium (ug/ L)
Ars
enic
(ug/L)
Conclusion
52% are colored mulches 36% colored mulches positive for arsenic
17% mulches contained plywood 67% mulches with plywood positive for arsenic
73% mulches with plywood were colored 82 % of colored mulches with plywood contained arsenic
44 % of South Florida samples detected positive for arsenic in SPLP analysis
75 % of open bin mulches contained high concentrations of arsenic
Conclusion Engineered wood was found in 21% of
consumer mulches Arsenic was found in 28% consumer
mulches SPLP tested showed that arsenic leached
from 27 % of consumer mulches 48% of these samples leached over 50 μg/L
Questions?
Report will be available in the next couple of months