乐清湾水环境特征及富营养化成因分析

根据2002-2003年乐清湾海域春、夏、秋、冬4个航次的调查资料,分析了乐清湾海域水化学要素在不同季节的分布和变化特征,探讨了陆源污水、海水养殖自身污染与富营养化的关系.结果表明,乐清湾水域DIN和DIP浓度全年平均分别为0.630mg/dm^3和0.039mg/dm^3秋、冬季几乎100%测站属劣四类水质,春、夏季近90%超过四类水质标准.水体营养状态指数（E）值各季平均在4～9,呈严重富营养化状态.研究指出沿岸工农业废水、生活污水的排放及水产养殖业的无序、无度发展是造成该水域严重富营养化的三个主要原因.认为目前乐清湾水质已不能满足该海域功能区划提出的要求,必须进行综合整治.

Characteristics of the Aquatic Environment and Causative Analysis of Eutrophication in Yueqing Bay

The distribution and variational characteristics of aquatic chemical parameters in the Yueqing Bay were discussed and the effect of waste water of continental source and aquaculture pollution itself on eutrophication was analyzed based on the data obtained in August and November, 2002 and February and May, 2003. The results showed that the average concentrations of DIN and DIP in four seasons were 0.630 and 0.039 mg/dm^3 respectively. The water quality of 100% investigated stations in autumn and winter were the inferior Grade IV of sea water quality standard and 90 % stations in spring and summer were poorer than Grade IV of sea water quality standard. The average nutritive indexes in each season were 4-9, presenting a heavy level of eutrophication. Our investigation also indicated that the discharge of industrial and agricultural waste water and the drainage of domestic sewage along the bay as well as the unorderly and excessive development of mariculture were the three main factors resulting in eutrophication in the Yueqing Bay.