南通市区河流底泥营养物质污染特征及环境风险分析

The Research of Nutrients Contamination Characteristics in Sediments in Nantong Urban Rivers and Assessment of Environmental Risks

以南通市区的学田河、南川河、法伦寺河、城山河及西山河为研究对象,测定了河流表层底泥中的有机质、总氮、氨氮、硝氮、总磷、无机磷及活性有机磷等营养物质指标,分析了污染最重的监测点的污染原因。此外,采用有机指数法、营养物质比值法进行了环境风险评价。得出各条河流底泥均为肥污染级,尤其污染最重的是西山河;各研究河流底泥的碳氮比都很高,说明其营养物质主要来源于周围环境;学田河和西山河底泥的氮磷比较高,说明它们的富营养化程度相对较高。通过回归分析,得出学田河、南川河、法伦寺河及城山河底泥中有机质与总氮及南川河有机质与总磷之间具有良好的线性相关性。

The content of organic matter, total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, inorganic phosphorus and organic phosphorus in sediments in Nantong urban rivers have been studied. The pollutant sources of the most contaminated sites have been analyzed. In addition, the environmental risks assessment by organic index and ratios of nutrients were conducted. According to the evaluation results, the organic pollution in sediments of each river was serious, especially in Xishan River;the radio of organic carbon and total nitrogen of each river was very high, which indicated that the main source of nutrients was the surroundings;the radio of total nitrogen and total phosphorus of Xuetian River and Xishan River was relatively high, which illustrated that their eutrophication was relatively severe. The correlation analysis showed that the organic matter and total nitrogen of Xuetian River, Nanchuan River, Falunsi River as well as Chengshan River, the organic matter and total phosphors of Nanchuan River have good linear correlations.