由于含有DDT的防污漆和林丹曾在我国使用，一些渔港`DDTs和HCHs的残留严重，湛江湾作为我国南方重要的渔港和养殖地区相关研究较少。为评估湛江湾HCHs和DDTs的残留状况和来源，本研究调查分析了湛江湾11个陆源入海排污口沉积物中HCHs和DDTs的含量、空间分布和来源。自1980s以来，研究区域HCHs的残留量明显下降，但DDTs含量变化较小，甚至在一些站位出现较高值。HCHs和DDTs组成和特征比值显示HCHs可能来自湛江湾周围土壤中残留的HCHs和近期少量的输入，DDTs可能来自工业DDTs的历史残留和含有DDTs的防污漆。根据沉积物质量指导，DDTs对海洋环境具有一定生态风险，可能对海洋生物体产生危害。本研究表明林丹和含有DDT的防污漆在湛江可能还有使用，相关部门应该加强控制管理，以及对现有污染区域的治理。

Contents of heavy metals, polycyclic aromatic hydrocarbons (PAHs), dichlorodiphenyltrichloroethanes (DDTs) and hexachlorcyclohexanes (HCHs) in surface sediments from mangrove areas of the Leizhou Peninsula were analyzed in July and November 2005. Risk assessment criteria applied by Long E R et al. (1995) and Long E D et al. (1998) (effects range low, ERL; effects range mean, ERM) of chemicals in sediments from the gulf or estuary were used to assess the potential ecological risks of heavy metals, PAHs, DDTs and HCHs to aquatic organisms in the studied area. The results indicated that the average contents of zinc, nickel, chromium, lead, copper, arsenic and mercury were (61.97±55.87), (59.99±39.01), (47.93±28.37), (26.64±13.00), (23.45±41.96), (9.32±3.62), (0.14±0.18) mg/kg in dry weight in the sediment samples collected from five studied sites in the Leizhou Peninsula, respectively. Cadmium was not calculated due to its content being below the detection limit (< 0.3 mg/kg). The average levels of Cr, Cu, Ni, Pb, Zn and Hg exceed their background values. The average contents of Ni were higher than ERM. The contents of PAHs in the sediments from the five studied sites were (79.78±43.70) ng/g in dry weight, far lower than ERL(4 022 ng/g). The contents of DDE, DDD and DDTs in the sediments from five studied sites were (2.60±4.68), (17.52±27.25), (27.78±46.64) ng/g in dry weight respectively, clearly higher than ERL, and the average contents of DDT were (7.66±15.93) ng/g in dry weight, much higher than ERM. HCHs could be detected in the sediments only from Gaoqiao sampling site, with the average contents (0.07±0.08) ng/g in dry weight.

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.