Element

Proportion of sample points (%)

Index average

Index maximum

No pollution

Slight pollution

Towards moderate pollution

Moderate pollution

Cr

99.07

0

0

0.93

−0.86

2.41

Cd

91.59

8.41

0

0

−0.55

0.49

Pb

96.53

3.74

0

0

−0.38

0.15

As

78.51

20.56

0.93

0

−0.46

1.42

Hg

89.72

7.48

2.8

0

−0.89

1.84