常熟市昆承湖水质时空变异特征和环境压力分析

采用综合指数法对近年来昆承湖水质变化趋势进行了分析,用模糊数学综合评价法对该湖2005年水质进行评价,用等级聚类法进一步分析了其水质的空间差异,用TSIM方法分析了昆承湖富营养化状况。结果表明:1998-2004年间,昆承湖污染总体上呈加重趋势,2003年污染最严重,在各污染因子中,氮污染负荷最大;昆承湖为Ⅴ类水或劣Ⅴ类水体;由于陆源污染差异和围网养殖的影响,湖区污染程度北湖>湖西区>南湖区;昆承湖TSI_M>70,呈现较严重富营养化。并分析了昆承湖所承受的巨大环境压力。

On Temporal-spatial Variability of Water Quality and Environmental Stress of Kuncheng Lake in Changshu City

Kuncheng Lake is one of the key freshwater lakes of Changshu City in Jiangsu Province.Temporal-spatial variability of water quality of the lake is analyzed by comprehensive index method,fuzzy mathematics and hierarchical clustering method,while eutrophication of the lake is assessed by TSIM indexes.The results show that quality of the lake water has degraded gradually in recent years,and has attained to or been worse than grade-Ⅴ;among all indexes,the total nitrogen pollution is most prominent;due to difference of terrestrial sources pollution and effects of encircling gear cultivation,pollution in northern and western parts are more serious than in southern part in this lake;and Kuncheng Lake has been subject to eutrophication.Non-point source,point source,domestic sewage pollution etc.of the lake are evaluated in this paper.