贡湖水质富营养化综合评价及初步预测

COMPREHENSIVE EVALUATION AND PRELIMINARY PREDICTION FOR WATER QUALITY AND EUTROPHICATION OF GONGHU BAY

对1996年7月贡湖三次调查资料进行的水质和富营养化现状综合评价显示：贡湖水质以Ⅲ-Ⅳ类为主，局部已出现V类，凯氏氮、非离子氨和总磷为主要污染物；营养类型以中营养和中富营养类型分布面积较广，富营养化水域出现在与梅梁湖相邻区，中营养水域则多位于水草生长茂盛的东部区域。从1987—1996年间夏季总磷、氨氮、CODMn、叶绿素a和藻类生物量变化趋势分析认为：贡湖氮、磷和有机物污染程度呈上升态势，水华渐增，且近期明显。用线性回归关系式预测2005年夏季，贡湖氨氮、CODMn和藻类生物量将分别达0．569mg／L、7．36mg／L和16．7mg／L，相当于或超过目前梅梁湖含量水平。

The existing state of water qulity and trophic level in Gonghu Bay of LakeTaihu were comprehensively eyaluated on the basis of three timeLys' surveying datacollegted in July 1996. The results show that Grade,Ⅲ-Ⅳ water area predominates over Grade V in the watar quality of Gonghu Bay. The main pollutants are Kjeldahl nitrogen, non-ion ammonia and total phosphorus. And mesotrophic and mesoeutrophic districts are broadly distributive. The eutrophic appears in the small part area, adjacent to Meilianghu Bay, and the mesotrophic is situated in the eastern region which water plants grow flourishing.By means of analysis for the variations of total phosphorus, NH3--N, CODMa,chorophyII-a and algal biomass in the summers of the last decade (1987-1996), nitrogen, phosphorus, organic pollutant and water bloom are all considered to be graduately increasing, especially in the recent years. with the method of linear regression NH5--N, CODMn, and algal biomass in Gonghu Bay were predicted to attain 0.569mg/L, 7.36mg/L and 16.7mg/L in the summer of 2005, respectively, matchingor exceeding the present pollution levels of Meiliang Bay.