城市不同功能区地表水重金属污染特性比较：以宁波为例

在宁波市工业区和商业区地表水中采集了85个水样,检测了6种重金属(Cd、Cr、Cu、Ni、Pb和Zn)的含量水平,分析了它们的空间分布特征;结合区域特征和计算重金属间的皮尔森相关系数推测了主要污染源;通过计算重金属的健康风险指数和致癌风险指数评价了潜在生态危害.结果表明,宁波市工业区和商业区地表水中重金属污染都比较严重,但存在差异.在工业区,重金属平均浓度的大小顺序为:Zn?NiPbCrCuCd,而超标的严重顺序为:CdPbCr?Zn,主要污染源为工业生产排放物.在商业区,平均浓度的大小顺序为:CrPb?ZnNiCdCu,超标的严重顺序为:CdPb?Cr,主要来自公路源污染.2个区所有采样点的地表水均存在一定的潜在健康风险和很高的致癌风险,在工业区和商业区潜在健康风险最大的重金属均是Cd、Cr和Pb;潜在致癌风险最大的重金属均是Cr,且商业区是工业区的1.7倍,相关部门应当足够重视.

Comparison of Heavy Metal Contamination Characteristics in Surface Water in Different Functional Areas: A Case Study of Ningbo

From industrial and commercial areas of Ningbo City, China, 85 surface water samples were collected. The concentrations of six heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) in the samples were measured, and the characteristics of the spatial distributions of those metals were analyzed. Through a combination of regional characteristics and Pearson correlation coefficients of the different heavy metals, the main pollution sources of the two areas were analyzed. The potential ecological risks of these heavy metals were evaluated by considering health risk and cancer risk indices. The results indicate that the heavy metal pollution of surface waters was serious in both the industrial and commercial areas. Furthermore, the differences between the two areas were also observed. In the industrial area, the average concentrations of the six heavy metals were, from highest to lowest, in the order: Zn >>Ni>Pb> Cr> Cu> Cd, and the main sources were industrial emissions. Four heavy metal concentrations exceeded the national environmental standard, which, from highest to lowest, were in the order: Cd> Pb> Cr >>Zn. In the commercial area, the average concentrations, from highest to lowest, were in the order: Cr> Pb >>Zn> Ni> Cd> Cu, and the main sources were road pollutants. Three heavy metal concentrations exceeded the national standard, and the order, from highest to lowest, was Cd> Pb>>Cr, with Cd and Pb having the most potential health risk. In both the industrial and commercial areas, there were some potential health risks and high carcinogenic risks. Cd, Cr, and Pb have the highest potential health risks, whereas Cr is the major potentially carcinogenic metal. The commercial area had 1.7 times the potential carcinogenic risk as that of the industrial area. The government should pay more attention to heavy metal pollution of surface waters in Ningbo City, China.