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Distribution of As concentrations in Florida surface soils 92%
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Have some ideas about metal concentrations in soils
Get familiar with FDEP Soil Cleanup Target Levels and regulations by different countries
Background metal concentrations in Florida soils
Factors controlling metal behaviors in soils
Soil processes and trace metalsSoil processes and trace metals
98 State Soil Arsenic 98 State Soil Arsenic Regulation Survey (ppm)Regulation Survey (ppm)
Survey by Association for Environmental Health and Sciences (2003)
State CO OH FL TX NJ MT
Background 4-40 0-30 0-3 1-18 0-350 0-100
Residential CG 0.4 4 2.1 20 20 250
Industrial CG 4 9 12 200 20 500
Distribution of As concentrations in Distribution of As concentrations in Florida surface soilsFlorida surface soils
3
818
37 38
90
77
50
37 35
2415
94 1 1
0
25
50
75
100
-2.3
1
-1.7
9
-1.2
7
-0.7
5
-0.2
3
0.29
0.81
1.33
Log concentration (As mg kg-1)
b. Log-transformed data
413
17
9
2 2 2
1 1
1
10
100
1000
Num
ber o
f sam
ples
0.0
6.0
12.0
18.0
24.0
30.0
42.0
54.0
As concentration (mg/kg)
a. original data
92% <3 ppm4% <6 ppm4% >6 ppm
Comparison of the UCL and the 95th percentile. As sample size increases, the UCL of the mean moves closer to the true mean, while the 95th percentile
remains at the upper end of distribution
Mean = 15.0 (50%)UCL = 16.5 (45%)95th = 27.5 (5%)97.5th = 27.5 (2.5%)
Chen, M., L.Q. Ma and W. Harris. 1999. Baseline concentrations of 15 trace elements in Florida surface soils. J. Environ. Qual. 28:1173-
1181.
97.5th percentile = excluding the highest 2.5%
95th percentile = 3.54 mg kg-1
Chen, M., L.Q. Ma and W. Harris. 1999. Baseline concentrations of 15 trace elements in Florida surface soils. J. Environ. Qual. 28:1173-
1181
Properties of Florida soils: mean of 7-8 soils
Ma, L.Q. F. Tan and W.G. Harris. 1997. Concentrations and distributions of 11 elements in Florida soils. J. Environ. Qual. 26:769-
775.
Soil Clay (%) OC (%) CEC (cmolkg-1)
Spodosols
A 1.29 2.30 12.2
E 1.04 0.17 1.35
Bh 3.03 2.23 20.2
Ultisols A 3.80 1.11 7.41
E 3.62 0.18 2.32
Bt 16.7 0.09 5.98
As (mg kg-1)
0.20
0.48
0.99
3.33
3.17
7.89
Elemental concentrations of Florida soils(mg kg-1)
Soil As Cr Cu Pb Ni
Spodosols A 0.20 3.05 1.89 3.16 6.95
E 0.48 3.45 2.37 2.93 7.19
Bh 0.99 4.68 3.04 2.93 7.29
Ultisols A 3.33 9.20 5.32 12.1 7.86
E 3.17 10.4 5.44 8.21 8.22
Bt 7.89 30.3 10.7 27.3 14.7
Mean [As] for Miami and Gainesville
0.00
2.00
4.00
6.00
Residential Commercial Parks Pbldg
Land use class
Arit
hmet
ic m
ean
(mg/
kg)
Gainesville Miami
Chirenje et al. 2003. Soil arsenic distribution in two Florida cities: Gainesville and Miami. J. Environ. Qual. 32:109-119. http://lqma.ifas.ufl.edu/Publication/Tait-03.pdf.