南淝河表层水中重金属空间分布、污染评价及来源

根据南淝河丰水期和枯水期水质的调查数据,采用单因子水质指数法和改进后的模糊综合评价法对水中重金属元素的污染进行了评价,确定了主要污染因子和优先控制断面,并利用主成分分析法对重金属污染进行了溯源分析。结果表明:Cr、Cu、Pb的含量平均值均为枯水期高于丰水期,而As、Cd的含量平均值均为枯水期低于丰水期。单因子水质指数法评价结果显示南淝河重金属污染的主要污染因子是Cd,丰水期和枯水期各采样点Cd的含量均达到地表水Ⅴ类水标准,最高值达到地表水Ⅴ类标准值的2.6倍。改进后模糊综合评价法评价结果显示南淝河水质丰水期基本属于地表水环境质量标准Ⅱ类水标准,潜山北路大桥断面污染最严重,属于优先控制断面,枯水期各断面水质均属于Ⅲ类水标准,整体上南淝河水质达到了水体功能区目标。主成分分析法结果显示,南淝河重金属污染的主要来源是流域内的农药化肥、机械制造和电镀行业的废水以及河道的行船。

SPATIAL DISTRIBUTION,CONTAMINATION ASSESSMENTS AND SOURCES OF HEAVY METALS IN SURFACE WATER FROM THE NANFEI RIVER

Based on the water quality investigation data of the Nanfei River during the wet and dry season,the single factor water quality identification index method and a improved fuzzy comprehensive evaluation model were employed to evaluate the quality status of heavy metals.The main pollution factors and the priority control section were determined.The principal component analysis (PCA) was applied to estimate the sources of heavy metal.The results showed that the average concentrations of Cr,Cu,Pb in dry season were higher than that in wet season,but the average concentrations of As,Cd in wet season were higher than that in dry season.The results of single factor water quality identification index method showed that the main pollution factors of heavy metal pollution in river Nanfeihe was Cd.The concentration of Cd in each sampling point exceeded the Class V according to standards of the national groundwater environmental quality during the wet and dry season.The highest value is 2.6 times Class V standard.The improved fuzzy comprehensive evaluation results showed that the water quality of the Nanfei River basically belonged to Class Ⅱ according to standard.The pollution of the section of Qianshan North Road Bridge was the most serious,and this section belongs to the priority control section.The water quality of the Nanfei River belonged to Class Ⅲ in dry season.Overall,the water quality of NanFei River reached the goal of water body function area.The contamination sources of heavy metals through the principal component analysis (PCA) revealed that the heavy metals contamination in NanFei River were caused by pesticides and fertilizers and wastewaters from mechanical manufacturing and electroplating industry and the boat in the river.