分级

Cu

Pb

Zn

Cr

Cd

Hg

As

第一类

≤35

≤60

≤150

≤80

≤0.5

≤0.2

≤20

第二类

≤100

≤130

≤350

≤150

≤1.5

≤0.5

≤65

第三类

≤200

≤250

≤600

≤270

≤5

≤1.0

≤93