Abstract: In order to understand the tissue accumulation of OCPs in five different diet fishes of Chao Lake, and to probe into the rationality of back muscle sampling method and the organochlorine pesticide risk of Chao Lake, we analyzed the concentrations of HCHs and DDTs in four muscle parts of five fish species from Chao Lake by the following methods of soxhlet extraction, sulfonate degrease, chromatographic column purification, rotary evaporation, nitrogen blow concentration, and analysis by GC/MS. Results showed that the average concentration of OCPs was from 2.929 ng/g to 10.523 ng/g. Specifically, concentrations in different fishes were listed as below: catfish (10.523 ng/g) > chub (6.407 ng/g) > snakeheaded fish (4.514 ng/g) > black carp (3.390 ng/g) > crucian (2.292 ng/g).OCPs in upper tail muscles (from catfish and snakeheaded fish) and belly muscles (from chub and black carp) were both significantly higher than those in back muscles. It was estimated that daily concentrations of HCHs and DDTs from species fish Chao Lake was far lower than daily food intake from national standard. In conclusion, concentrations of OCPs in typical fishes of Chao Lake appeared that carnivore fishes > phytophagous fishes > polyphagia fishes. The accumulation of OCPs in back muscle was just one of the features of OCPs in entire fish muscles.

Key words: Chao Lake, fish, OCPs, enrichment, accumulation features