Sample sites

Soil layers

Heavy metals (mg∙kg⁻¹)

HPI

Cr

Cd

Pb

As

Hg

Xiwang

T

27.92 ± 0.56

1.08 ± 0.29

29.38 ± 2.61

9.78 ± 0.18

1.44 ± 0.05

6.60

S

21.08 ± 0.95

0.83 ± 0.36

26.67 ± 0.19

8.90 ± 0.51

1.26 ± 0.03

5.55

Wenchang

T

34.21 ± 0.52

1.17 ± 0.14

17.08 ± 1.72

10.24 ± 0.91

0.48 ± 0.02

5.07

S

31.38 ± 2.10

0.91 ± 0.40

13.58 ± 3.22

9.37 ± 0.50

0.45 ± 0.01

4.39

Fanyao

T

32.13 ± 1.63

1.13 ± 0.33

23.63 ± 1.44

16.52 ± 0.72

0.44 ± 0.02

5.74

S

28.17 ± 1.86

0.63 ± 0.45

20.29 ± 4.84

15.07 ± 0.43

0.40 ± 0.02

4.65

Sanyuan

T

42.17 ± 0.52

2.13 ± 0.63

20.42 ± 3.21

13.48 ± 0.41

1.41 ± 0.79

8.10

S

31.50 ± 1.02

1.42 ± 0.44

18.33 ± 1.87

12.34 ± 0.36

1.10 ± 0.06

6.45

Dongzhang

T

26.38 ± 0.78

0.83 ± 0.40

21.58 ± 2.80

11.98 ± 0.62

0.53 ± 0.01

4.96

S

20.21 ± 1.92

0.71 ± 0.36

18.71 ± 2.42

9.91 ± 1.07

0.51 ± 0.01

4.23

Nanzhuang

T

30.42 ± 1.99

2.08 ± 0.51

22.04 ± 6.47

15.92 ± 0.90

0.34 ± 0.02

5.96

S

22.21 ± 1.23

0.83 ± 0.07

20.37 ± 2.28

13.88 ± 1.21

0.28 ± 0.02

4.29

Dongbai

T

36.29 ± 2.37

3.17 ± 0.26

19.38 ± 2.55

12.79 ± 0.84

0.67 ± 0.04

7.18

S

29.13 ± 0.45

2.88 ± 0.13

19.04 ± 2.60

11.12 ± 0.43

0.61 ± 0.02

6.41

Limit (pH > 7.5)

250

0.40

50

20

0.35