[Bioindication of organochlorine pesticides by night heron in Taihu wetland ecosystem].

Based on field ecological investigation on the colony of herons in Yuantouzhu of Taihu in 1999, the regurgitated foods by chicks of night heron were collected for prey type identification and chemical analysis. Besides, eggs of night heron, and sediments and waters in foraging habitats were sampled for chemical analysis as well. alpha-HCH, beta-HCH, gamma-HCH, Aldrin, Dieldrin, Endrin, Heptachlor, Heptachlor epoxide, p,p'-DDE, p,p'-DDD, o,p'-DDT and p,p'-DDT were determined in laboratory by gas chromatography. The results indicated that HCH isomers, DDT and its metabolites could be detected in various environments and preys of night heron, although the organochlorined chemicals were banned for almost 20 years. Moreover, The results showed that eggs of night heron could accumulate organochlorine pesticides by as much as a factor of 10(3)-10(4), which can make chemical analysis much easier. So they are good bio-indicators for organochlorine contamination level in wetland environments.