Pollution Characteristics and Potential Ecological Risk of Heavy Metals in Urban Surface Water Sediments from Yongkang
【Abstract】In order to understand the pollution characteristics of heavy metals in surface water sediments of Yongkang, we analyzed the concentrations of 10 heavy metals including Ti, Cr, Mn, Co, Ni, Cu, Zn, As, Pb and Fe in 122 sediment samples, explored the underlying source of heavy metals and then assessed the potential ecological risks of those metals by methods of the geo-accumulation index (Igeo) and the potential ecological risk. The study results showed that: 10 heavy metal contents followed the order: Fe > Ti > Mn > Zn > Cr > Cu > Pb > Ni > As > Co; all heavy metals except for Ti were 1.17 to 3.78 times higher than those of Zhejiang Jinhua-Quzhou basin natural soils background values. The concentrations of all heavy metals had a significantly correlation between each other, indicating that those heavy metals had similar sources of pollution, and it mainly came from industrial and vehicle pollutions. The pollution extent of heavy metals in sediments by Igeo followed the order: Cr > Zn > Ni > Cu > Fe > As > Pb >Mn > Ti; thereinto, Cr, Zn, Cu and Ni were moderately polluted or heavily polluted at some sampling sites. The potential ecological risk of 9 heavy metals in sediments were in the following order: Cu > As > Ni > Cr > Pb > Co > Zn > Mn > Ti; Cu and As contributed the most to the total potential ecological risk, accounting for 22.84% and 21.62%, and others had a total of 55.54%. Through the ecological risk assessment, 89.34% of the potential ecological risk indexes (RI) were low and 10.66% were higher. The contamination level of heavy metals in Yongkang was slight in total, but was heavy in local areas.
【Keywords】 Yongkang City; surface water; sediments; heavy metal; ecological risk assessment;
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