The residual levels and health risks of hexachlorocyclohexanes (HCHs) and dichloro-diphenyl-trichloroethanes (DDTs) in the fish from Lake Baiyangdian, North China.

The tissue and organs (muscle, brain, liver, and gill) of four species of freshwater fish from Lake Baiyangdian were analyzed for hexachlorocyclohexanes (HCHs) and dichloro-diphenyl-trichloroethanes (DDTs). The distribution characteristics were analyzed for HCHs and DDTs in various tissue and organs, which determined the health risks for humans. The research results showed that the wet weight content of all HCHs (∑HCHs) ranged from 0.05 ∼ 14.53 ng g(-1), with a mean of 3.47 ng g(-1). The wet weight content of all DDTs (∑DDTs) ranged from ND to 8.51 ng g(-1), with a mean of 2.41 ng g(-1). For the various species of fish, the residual level of ∑HCHs was relatively higher in chub and grass carp and lowest in snakehead. The residual level of ∑DDTs was the highest in snakehead and did not exhibit a significant variance in the other three species. For the various tissues and organs, the contents of HCHs and DDTs were both highest in the fish liver, second highest in the fish gill, and lowest in the fish brain and muscle. Among the four types of isomers, the residual level of γ-HCH was relatively higher, while the residual level of α-HCH was the lowest. The content of p,p'-DDE was significantly greater to other forms of DDT and its isomer. The residual levels of HCHs and DDTs in fish were both below the national standard. However, the carcinogenic risk from the HCHs in parts of the tissue and organs of four fish species in Lake Baiyangdian exceeded the screen value threshold set by USEPA.