三峡库区城镇污染河流沉积物重金属风险评价与来源分析

以三峡库区城镇化发展迅速的典型流域——梁滩河为研究对象,分析了不同河段沉积物重金属含量,用地累积指数Igeo和沉积物污染指数SPI评价了沉积物重金属的累积程度和生态潜在风险,并用主成分分析和相关分析方法探讨了重金属来源.结果表明:梁滩河沉积物As、Cd、Cr、Cu、Ni、Pb、Zn、Hg的质量分数变化范围分别处于(2.31~8.56)×10-6,(0.074~0.574)×10-6,(92.85~336.13)×10-6,(19.22~45.35)×10-6,(13.50~48.37)×10-6,(11.77~52.17)×10-6,(46.91~1035.30)×10-6和(0.012~0.229)×10-6.沉积物重金属生态潜在风险较低(SPI为1.11~6.90),但个别重金属累积污染严重,Cr和Zn累积达到超重污染;Cd、Hg在人口聚集地区达到中度污染.相关分析和主成分分析表明:河流污染治理工程实施后,沉积物重金属主要来自于城镇生活污染.

Heavy Metal Risk Assessment and Sources Distinguishing in Town Polluted River Sediment at the Three Gorges Reservoir

The Liangtan River is the typical river basin for urbanization pollution research in the Three Gorges Reservoir,and sediment samples in the basin were collected to analyse heavy metal concentrations for risk assessment and sources distinguishing. These results showed that As、Cd、Cr、Cu、Ni、Pb、Zn、Hg in sediment ranged in( 2. 31- 8. 56) × 10- 6,( 0. 074- 0. 574) × 10- 6,( 92. 85- 336. 13) × 10- 6,( 19. 22-45. 35) ×10- 6,( 13. 50- 48. 37) × 10- 6,( 11. 77- 52. 17) × 10- 6,( 46. 91- 1 035. 30) × 10- 6and( 0. 012- 0. 229) × 10- 6,respectively. Sediment risk index( SPI) suggested that the sediment kept in slight pollution and low ecologiclal risk with values ranged from 1. 11 to 6. 90. However,some heavy metals got polluted independently. Cr and Zn had reached serious pollution in sediment. Meanwhile,Cd and Hg aggavated in the population concentration areas which reached middle polluted state. The correlation and principal component analysis( PCA) suggested that the heavy metals of basin came from urban domestic pollution after river pollution control engineering processed.