Trace organic pollutants in the southeast estuarine environments of China

Trace organic pollutants (PAHs, DDTs, HCHs, PCBs) in sediments, suspended particulate matter and bivalves were studied during 1994 and 1997 in three estuaries of China: the Jiulong River, the Minjiang River and the Pearl River estuaries. Results indicated that there were some differences between the composition characteristics of the trace organic pollutants in the suspended particulate matter and the sediments. Concentrations of trace organic pollutants in the bivalves were 2-300 times higher than those in the sediments. In the three estuaries, the concentrations of PAHs and PCBs were relatively higher in Pearl River estuary, but the concentrations of DDTs were higher in Jiulong River and Minjiang River estuaries. Relatively high values of PAHs appeared at the outlet of river, waterway and harbor. It is suspected that these PAHs mainly came from sewage, shipping discharge and local pollutant sources. Relatively high concentrations of PCBs appeared at the Pearl River estuary that may be related to industrial development. The ratios of DDT to DDTs indicated that DDT may not be newly released into these estuaries. Compared with other estuaries in the world, the sediments of the southeastern estuaries of China had not been polluted. However, the concentrations of trace organic pollutants in organisms were close to the lower limits of food criteria. Thus, the control of trace organic pollutants in these marine environments is very important.