Cd (mg/kg)

Pb (mg/kg)

average

1.31

64.17

maximum

31.98

889.92

median

0.61

32.07

minimum

0.02

2.68

standard deviation

2.55

110.35

coefficient of variation

195.32

171.96

background value of Yunnan province

0.218

40.6

Risk screening value

pH ≤ 5.5

0.3

70

5.5 < pH ≤ 6.5

0.3

90

6.5 < pH ≤ 7.5

0.3

120

pH > 7.5

0.6

170