我国东部沿海城市内河重金属污染现状和健康风险评价——以宁波为例

Distribution and Health Risk Assessment of Heavy Metals in Inland River in Eastern Coastal Cities in China——Take Ningbo City for Example

以宁波为例,研究了我国东部沿海城市内河重金属的污染现状,并对其存在的健康风险和致癌风险进行了评价.结果表明,对照GB3838-2002《地表水环境质量标准》中的Ⅴ类标准限值,我国东部沿海城市内河Cd污染广泛,商业区的Cr污染比较严重,部分断面Pb浓度超标,Cu和Zn均未超标,Ni无对应标准.在所有监测断面中,70%以上的断面重金属对人类健康存在风险;特别是Cd和Cr的危害指数最高,其次是Pb,单个Zn、Cu和Ni不会对人类健康造成威胁.Cd和Cr存在很高的致癌风险,特别是Cr金属的致癌风险已达到临界值的15万倍左右,人们直接或间接摄入城市河水都有可能导致癌症.可见,我国东部沿海城市内河重金属污染严重,对人类健康存在很大的健康危害和致癌风险.

Taking Ningbo for example, the current situation of heavy metals pollution in inland river was investigated for eastern coastal cities in China, and the health risk and carcinogenic risk of these heavy metals were evaluated. The risk indices of heavry metals have been calculated and analyzed. The results showed that, by contrasting the standards of classⅤof Environmental Quality Standards for Surface Water（GB 3838-2002）, the Cd pollution was prevalent in inland river of eastern coastal cities. The Cr pollution in commercial districts was more serious than that of industrial districts. In some monitoring sections, Pb concentrations exceed the national standard. The concentrations of Zn and Cu were all below the limit of the national standards, while there is no limit for Ni. There was risk of affecting the human health by heavy metals pollution in more than 70% monitoring sections, especially Cd and Cr had the highest risk indices, followed by Pb. The risks of Zn, Cu and Ni would be negligible. Moreover, the carcinogenic risk of Cd and Cr was very high, especially the carcinogenic risk indices of Cr is about 150 000 times of the thresh-hold level, so cancers would be caused by either direct or indirect ingestion of water from inland river. In conclusion, the heavy metals pollution in inland river of eastern coastal cities in China are very serious, there are high health hazard and very high carcinogenic risk.