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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.