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 |