沙河流域重污染支流表层沉积物中氮、磷和重金属的空间分布特征及污染评价

SPATIAL DISTRIBUTION CHARACTERISTICS AND POLLUTION ASSESSMENT OF NITROGEN, PHOSPHORUS AND HEAVY METAL IN SURFACE SEDIMENTS OF HEAVILY POLLUTED TRIBUTARIES OF SHAHE RIVER BASIN

为探明东江支流沙河流域重污染支流表层沉积物氮、磷及重金属风险分布规律,采用不同风险等级评价法进行分析。综合污染指数分析显示,TN风险等级分为重度污染、中度污染、轻度污染、清洁,占比分别为57.1%、14.3%、16.1%、12.5%,TP占比分别为62.5%、10.7%、21.4%、5.4%。重金属Cr、Ni、Cu、Zn、Cd、Pb、Hg平均浓度分别超对应广东省背景值的5.52,7.43,15.88,6.70,8.10,1.34,1.12倍,相关性分析与主成分分析法推测Cr、Ni、Cu、Zn、Cd、Pb主要来自造纸、电镀行业;Hg来自电池或金属制造业;As含量不超标,主要来自农药及化肥;地积累指数法显示Cu、Ni以及Cr污染严重,潜在生态危害指数法显示Cd与Cu是主要生态危害贡献因子。研究结果可为饮用水源型河流水质安全保障提供决策支持。

In order to find out the risk distribution of nitrogen, phosphorus and heavy metals in the surface sediments of the heavily polluted tributaries in Shahe basin, a tributary of Dongjiang River, different risk assessment methods were used. The comprehensive pollution index analysis showed that TN risk levels of heavy pollution, moderate pollution, light pollution and clean accounted for 57.1%, 14.3%, 16.1% and 12.5%, respectively, while the TP risk levels of heavy pollution, moderate pollution, light pollution and clean level accounted for 62.5%, 10.7%, 21.4% and 5.4%, respectively. The average concentrations of Cr, Ni, Cu, Zn, Cd, Pb and Hg were 5.52, 7.43, 15.88, 6.70, 8.10, 1.34 and 1.12 times higher than the background values of heavy metals in Guangdong Province, respectively. Correlation analysis and principal component analysis suggested that Cr, Ni, Cu, Zn, Cd and Pb mainly came from papermaking and electroplating industries;Hg mainly came from battery or metal manufacturing industries;As did not exceed the standard, mainly came from pesticides and fertilizers;the geoaccumulation index showed that Cu, Ni and Cr were seriously polluted;the potential ecological hazard index showed that Cd and Cu were the main ecological hazard contributing factors. The results could provide decision support for water quality security of rivers as drinking water sources.