灰色聚类法评价淀山湖水质状况

2004年逐月在淀山湖6个站点进行水质参数测定。水质参数在各站点的月平均变化范围为DO7．210～9．943（mg／L）、BOD53．810～4．940（mg／L）、CODMn6．016～7．053（mg／L）、TP0．137～0．366（mg／L）、NH3．N2．176～3．362（mg／L）、Chl．a29．814～56．02（mg/m^3）。对各站点2004年水质参数的月平均测定结果应用灰色聚类方法进行富营养化程度和水环境质量等级评价，结果显示：调查的六个站点全部处于富营养化水平；六个站点的水质全部处于V类水等级。在灰色聚类法评价水质过程中，权系数最大的是氮、磷及叶绿素a。因此，在淀山湖人工栽植水草进行脱氮除磷、放养滤食性鱼类抑制藻类大量繁殖是改善淀山湖水质的有效途径。

Eutrophic status and water quality grade evaluations of Lake Dianshan based on grey-clustering method

Based on the data of water quality parameters sampled monthly from six stations of Lake Dianshan in 2004,the author aimed at evaluating eutrophic status and quality grades with the grey-clustering method.Water quality parameters of DO,BOD_5,COD_(Mn),TP,NH_3-N,Chl.a in Lake Dianshan monthly means ranged at 7.210-(9.943)mg/L,3.810-4.940 mg/L,6.016-7.053 mg/L,0.137-0.366 mg/L,2.1763.362 mg/L,29.814-(56.02) mg/m~3 respectively.The evaluating results showed that(1) Lake Dianshan was in the eutrophic status at six sampled sations;(2) the water quality of this lake was in V-grade level.In the process of evaluation by grey-clustering method,TP,NH_3-N,Chl.a were found to be the most important water quality parameters which contributed to eutrophic status and quality grades.The article suggested the effective measures to improve the water quality of Lake Dianshan are to remove the surplus nitrogen and phosphorus by planting the aquatic grass,and to restrain the algae blooming by rearing the filter fish.