[Residual levels of pesticides in freshwater fish from Beijing aquatic product markets and health risk assessment].

Health risks by fish consumption were assessed following the investigation of the residual levels of 25 pesticides in four kinds of freshwater fish from 4 aquatic product markets in Beijing using ultrasonic extraction-GC-MS. Eighteen pesticides were detected from the 48 samples collected. Acetochlor (97.9%) and beta-HCH (93.8%) showed high detection rates. The pesticide detected in highest concentration was chlorothalonil (1 779.4 microg x kg(-1)), followed by deltamethrin (620.3 microg x kg(-1)). Coexistence of 2-10 kinds of pesticides in fish was found with the total pesticide concentration in range of 2.7-1932 microg x kg(-1). Based on the averaged fish consumption of Beijing residents, the health risk of the studied pesticides by freshwater fish consumption was calculated as 0.043 43, suggesting a relatively low health risk.