ORGANOCHLORINATED COMPOUNDS IN WATERS OF THE PEARL RIVER DELTA REGION

Samples of river water and sewage water were analysed for ten PCB cong eners, chlorobenzenes and chlorinated pesticides (BHCs and DDT) in thr ee cities (Guangzhou, Shenzhen and Zhaoqing) in the Pearl River Delta, The results showed that the sewage water in Shengzhen had the highest concentration of total PCBs at about 10ng/L, and Dasha River (Shengzh en), the lowest at about 1.Ong/L. In general, the sewage waters in the three cities had higher concentrations of PCBs than river waters. Chl orobenzenes were investigated in the water samples. The total concentr ations of chlorobenzenes ranged from 0.02 similar to 0.13 mu g/L, the Dasha River had the highest level of chlorobenzenes, and the sewage wa ter in Zhaoqing had the next highest. The result may be related to the discharges production factories nearby the sampling sections of the D asha River (Shenzhen) water in Zhaoqing. The concentrations of organoc hlorinated pesticides (alpha-BHC, gamma-BHC, delta-BHC, DDT and DDE) c hanged little in all water samples except for the sewage water in Guan gzhou. It seemed that these pesticides are more a residual signal than a direct discharge from point sources.