Distribution of organochlorine compounds in water, porewater and sediments in Xiamen Harbour

The Concentrations of 18 organochlorine pesticides and 12 polychlorinated biphenyls (PCBs)in water,porewater and sediments from the Xiamen Harbour were analyzed quantitatively.It shows that,the levels of all organochlorine insecticides varied from 6.60 to 19.6 ng/dm³ (in water),11.9-78.5 ng/dm³(in porewater) and not detected(ND)-0.58 ng/g dry weight (in sediments),and those of total DDTs were in the range ND-0.06 ng/g dry weight.Concentrations of PCBs and insecticides in porewater were higher than in surface water,due to the higher affinity of these hydrophobic compound for sedimentary phase than to water.It implies there would be a potential flux of pollutants from sediments to ovenerlying water.Compared with the concentrations of these polutants measured in the Xiamen Harbour in 1993,it is one to several magnitude order lower,which suggests their inputs have been decreased in recent years and possible degradation of these compounds.The levels of these pollurants were also compared with other estuaries.