广西刁江流域主要河流水质评价

Water quality assessment of the Diaojiang River Basin in Guangxi

为研究广西刁江水质污染现状,从刁江流域上游到下游共设置9个水质监测断面。于2013年12月-2014年12月对河流的p H、溶解氧、高锰酸盐指数、叶绿素a、总氮、总磷、氨氮、硝酸盐氮、亚硝酸盐氮、正磷酸盐、重金属(砷、铅、镉、汞、铬)水质指标进行监测。采用单因子和综合污染指数对刁江水质进行评价,同时开展水体富营养化评价。单因子污染指数评价结果表明刁江流域主要污染物为总氮和砷。综合污染指数评价结果表明刁江流域水质整体较好,但上游的平村河污染较严重。从时间分布来看,秋季水质最差,冬季较好。从营养化状态指数来看,平村河为中度富营养化状态,其余河流为中营养状态,富营养化程度呈现春夏高,冬季低的特点。对评价结果进行主成分分析,结果表明刁江流域总氮最大的贡献者可能来源于居民的生活污水。

In the present work, nine water quality monitoring sections were set up from the upstream to downstream of the Diaojiang River to investigate the pollution characteristics there. Water quality parameters including pH, DO, BODMn, chlorophyll-a, total nitrogen, total phosphorus, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, positive phosphate, As, Pb, Cd, Hg and Cr were monitored from December 2013 to December 2014.Water quality of the Diaojiang River was assessed using single factor pollution index, comprehensive pollution index and eutrophication index. Single factor pollution index assessment suggested that total nitrogen and As were the main pollutants in the Diaojiang River. Comprehensive pollution index assessment suggested that the water quality of the Diaojiang River was good at most monitoring sections, with exception of the upstream section in the Pingcun River, where serious pollution was found. Temporally, worst water quality was monitored in autumn, while best water quality was monitored in winter. With respect to eutrophication, the Pingcun River was at medium eutrophication level, while other monitoring sections were at medium nutrient level. Distinct seasonal variation was observed for eutrophication level, with high eutrophication levels in spring and summer and low level in winter. Principle component analysis indicated that domestic sewage was the most important source to total nitrogen in the Diaojiang River.