Pollution Of The Nutrients And The Heavy Metals In River Sediments From Small Towns, Shanghai

The paper takes the sediments in the rivers of three small towns as our research object. Our research matter is centralized in some indexes such as the content, speciation, distribution, transportation, transformation and evaluation of nutrient and heavy metals in sediment. By analyzing the district character and pollution character etc. of pollutant, we aim at opening out the pollution character of water system in small towns of suburb. Our main research findings are as follows.(1) The pollution character of nutrient in waters of small towns is researched and the results show that TP in all river samplings of Fengjing and Jujiajiao town in summer is above V level. The content of TP in spring and summer is higher than that in autumn and winter and the pollution status in medium and small sized rivers are relatively prominent, while in Songjiang town it shows that the content of TP in autumn and winter is higher than that in spring and summer, which reflects the effect of releasing endogenous phosphorus on waters. The content and proportion of NH3+N in waters of Fengjing and Jujiajiao town is high in summer, but the regular pattern isn't so obvious in Songjiang town, which makes out that sediment is one important origin of ammonia and nitrogen in waters. The regional variance of the content of ammonia and nitrogen in rivers of three small towns has a great variation in summer, which basically reflects semi-urbanization character of small towns.(2) The charater of TP and morphological phosphorus in rivers of small towns is studied. It shows that the content of TP in river sediment of small towns is obviously higher than that in other sediment. The content of TP in medium sized river sediment is higher than that in large and small sized rivers sediment of small towns. The average content of TP in large and medium sized river sediment is correspondingly high in summer. The variation content of TP in medium sized river sediment for each season is the biggest in Zhujiajiao town, while only in summer it has the trend for Songjiang and Fengjing town. The variation content of TP in large sized river sediment is the biggest in autumn and winter. The organic content of river sediment in Fengjing and Jujiajiao town in summer is lower than that in other seasons. At the same time the organic content in medium sized river sediment is correspondingly abundant which shows that it comes from the sanitary waste. The organic matter and TP shows determinate correlation in the sediment of small towns, which illuminates that sanitary waste is of their common origin. The content and proportion of Ca-P is higher thanFe-P in river sediment of small towns. The regional variation of Fe-P content and proportion in sediment is great, which means environmental pollution of small towns shows typical non-point pollution character.(3) Pollution character of IN in the river sediment of small towns is studied. As a result, we find that the content and proportion of NH₃⁺N in the river sediment of small towns is higher than other morphological IN. The content and proportion of NH₃⁺N in sediment in summer is higher than that in autumn and winter. The regional variation of NH₃⁺N is great, while the ratio of NH₃⁺N /TIN is small, which effectively disclose that environmental pollution of small towns has the character of consistency and otherness.(4) We research pollution character of TP in river sediment of town and village resident area. It shows that the content of TP and regional variation in river sediment of town resident area is higher than that of village resident area. The content of TP in river sediment of village resident area near Dianshan Lake is reversely low, while the content is correspondingly high in junction site between towns, which shows that environmental pollution of resident area is controlled by high-intensity human activity and environmental administration. The content and proportion of OP in river sediment of resident area in Jujiajiao town is comparatively high, while the content and proportion of DP is low. The content of ea...