A.≥9.5mg/L B.≥7.5mg/L C.≤9.5mg/L D.≤7.5mg/L
A.8 B.5~10 C.10 D.6~9
A.≤0.01(湖、庫(kù)0.005) B.≤0.1(湖、庫(kù)0.025) C.≤0.2(湖、庫(kù)0.05) D.≤0.3(湖、庫(kù)0.1)