Distribution of organochlorine pesticides in the liver of waterbirds from Honghu wetland, Central China

Twenty organochlorine pesticides (OCPs) were measured in the liver of six waterbird species from Honghu wetland. Among OCPs, DDTs were the most prevalent compounds (38.3%~93.0%), with average concentration ranging from 2.74 to 121.72 ng/g wet weight. The accumulation profiles of HCHs and DDTs suggested that these OCPs in the Honghu wetland were largely derived from historical usage. Significant interspecific differences were observed in the levels of sum OCPs in the liver of all waterbirds (P<0.01). Concentrations of total OCPs in little egrets (Egretta garzetta) and chinese-pond herons (Ardeola bacchus) (37.91~137.22 ng/g wet weight) were higher than those in the other birds (5.00~21.49 ng/g wet weight), which might be attributed to their different dietary habits. Higher average concentrations of OCPs were observed in males (little egrets: 136.90 ng/g wet weight; chinese-pond herons: 52.41 ng/g wet weight) than in females (little egrets: 126.60 ng/g wet weight; chinese-pond herons: 49.78 ng/g wet weight) for little egrets and chinese-pond herons. Compared with other regions worldwide, concentrations of OCPs in waterbirds from Honghu wetland were at low levels. The analysis of risk assessment indicated that the concentrations of OCPs detected in the present study were not expected to pose any hazard to waterbird populations.