涡湖水质调查与富营养状态评价

于2004年4月-2005年4月对涌湖水质进行调查，分析了透明度、pH值、DO、生化需氧量、高锰酸盐指数、总无机氮、总磷等水质参数年内变化规律。采用涌湖富营养状态指数评价其富营养化程度，并对比了20年来该湖富营养化状况。研究表明，涌湖水体夏季DO为3．98mg／L、生化需氧量年均值为4．98mg／L、高锰酸盐指数年均值为4．59mg／L、总无机氮年均值为1．37mg／L、总磷年均值为0．209mg／L；除南部部分水域属中-富营养后期外，大部水域营养状态处于富营养期，且富营养化程度由北向南逐渐减弱；氮磷物质含量明显上升是造成富营养化的主要原因；上游来水水质恶化和网围养殖过密造成水质污染和湖泊环境功能破坏，从而导致氮磷累积。

Water quality investigation and eutrophication status evaluation in Gehu Lake

By investigating water quality of Gehu Lake from Apr. 2004 to Apr. 2005, an analysis is made to development trends of parameters such as diaphaneity, pH, DO, BOD, CODMn, TIN and TP. Eutrophication evaluation was carried out by calculating eutrophication status index of Gehu Lake and contrasting with eutrophication status in twenty years. The results arrived as DO in summer is 3.98 mg/L, BOD average is 4.98 mg/L over the year, CODM, average is 4.59 nag/L, TIN average is 1.37 mg/L and TP average is 0.209 mg/L. Getting rid of the later-mesotrophy stage in south, the eutrophication status of Gehu Lake is eutrophy stage. And the grade weakens gradually from north to south. It is the primary reason of eutrophication that the content of phosphorus and nitrogen in the water body has risen evidently. Water quality of upriver deteriorates and the dense aquatic culture causes pollution, and environmental functions have been damaged and nutrition has accumulated.