广州市主要湖泊沉积物重金属污染与生态风险评价

    Heavy Metal Pollution and Potential Ecological Risk Assessment in Surface Sediments From Lakes Located in Guangzhou City

    • 摘要: 对广州市主要湖泊表层沉积物重金属Cd、Cr、Cu、Ni、Pb和Zn含量及其空间分布特征进行分析,并采用地累积指数法、富集系数法和潜在生态风险指数评价重金属污染现状和潜在生态风险。结果表明,广州市主要湖泊沉积物中Cd、Cr、Cu、Ni、Pb和Zn含量范围分别为0.50~6.90、36.00~197.40、32.35~432.00、17.35~155.50、32.50~162.70和71.83~853.40 mg·kg-1,平均值分别为2.54、92.27、165.20、70.21、90.48和447.88 mg·kg-1,明显高于广东省土壤重金属背景值。在空间分布上表现为白云湖和东山湖重金属含量高于流花湖和花都湖;地累积指数和富集系数评价结果表明,各重金属污染程度表现为Cd > Cu > Zn > Ni > Pb > Cr;潜在生态风险指数评价结果表明,Cd为主要生态风险因子,其中白云湖和东山湖重金属污染达到极严重生态风险水平,流花湖和花都湖为严重生态风险水平;多元统计分析结果表明广州市湖泊重金属污染来源主要为城市地表径流和工业、生活污水直接或间接排放。

       

      Abstract: The surface sediments collected from major lakes located in Guangzhou City were analyzed for the concentration and spatial distribution of Cd, Cr, Cu, Ni, Pb and Zn. The pollution and potential ecological risk of which were assessed using the methods of geo-accumulation index, enrichment coefficient and potential ecological risk index. The results show that the concentrations of Cd, Cr, Cu, Ni, Pb, and Zn were 0.50-6.90, 36.00-197.40, 32.35-432.00, 17.35-155.50, 32.50-162.70, 71.83-853.40 mg·kg-1, with average of 2.54, 92.27, 165.20, 70.21, 90.48, 447.88 mg·kg-1, respectively, being significantly higher than those of background values in soils of Guangdong Province. As for spatial variation, the concentrations of heavy metals were higher in Baiyun Lake and Dongshan Lake than those of Liuhua Lake and Huadu Lake. Based on geo-accumulation index and enrichment coefficient, that the heavy metals pollution followed the order of Cd > Cu > Zn > Ni > Pb > Cr. According to the potential ecological risk factor, Cd was identified as the key ecological risk factor and the result indicate that Baiyun Lake and Dongshan Lake met the extreme serious ecological risk, Liuhua Lake and Huadu Lake fall at the level of serious ecological risk. Multivariate statistical analysis indicate that the heavy metals in lakes of Guangzhou City were mainly derived from the runoff of city, and direct and indirect discharge of industrial and domestic sewage.

       

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