牛谷河表层沉积物氮、磷、有机质的分布及污染评价

以牛谷河沿河及西河入牛谷河口布置的36个采样点为研究对象，采用SMT法、元素分析仪法、重铬酸钾法和筛析法对表层沉积物总磷（TP）、总氮（TN）、有机质（OM）和粒度进行监测，分析其空间分布规律及TN、TP、OM的相关性，并运用综合污染指数法和有机污染指数法对牛谷河表层沉积物污染现状进行评价。结果表明:牛谷河表层沉积物中TN、TP、OM的均值分别为697.18，920.31 mg/kg和4.47%，TN、OM空间上表现为中游高于上下游（A、B段>C、D段），TP则为中下游高于上游（A、B、D段>C段）；各段表层沉积物中C/N表明:C、A、D段有机质主要来自外源，B段内外源基本平衡；综合污染指数和有机污染指数均值分别为1.38和0.19，2种评价结果均显示牛谷河表层沉积物为轻度污染状况，其中TP的污染指数（S_TP）均值达到1.36，为重度污染；指标间的Pearson相关性分析表明，TN、TP、OM三者间均呈显著正相关（P<0.01）。

DISTRIBUTION CHARACTERISTICS AND POLLUTION ASSESSMENT OF NITROGEN,PHOSPHORUS AND ORGANIC MATTERS IN SURFACE SEDIMENTS OF THE NIUGU RIVER

Taking 36 sampling points arranged along the Niugu River and Xihe River inlets as the research objects, SMT method, elemental analyzer and potassium dichromate method were employed to monitor the contents of TP, TN and OM, respectively. Spatial patterns and correlations of TN, TP and OM were examined. At the same time, comprehensive pollution index and organic pollution index was employed to evaluate pollution status. The results showed that the average contents of TN, TP and OM were 697.18 mg/kg, 920.31 mg/kg and 4.47%, respectively. The content of TN and OM in the middle reaches was higher than that in the upper and lower reaches(A,B>C,D), and the content of TP in the middle and lower reaches was higher than that in the upper reaches(A,B,D>C); C/N of each part indicated that the organic matter of C, A and D segments mainly came from external sources, and the internal and external sources of B segments were basically balanced. The average values of comprehensive pollution index and organic pollution index of surface sediment in Niugu River were 1.38 and 0.19, respectively. Both evaluation results showed that the surface sediment of Niugu River was slightly polluted, but the average pollution index of TP was 1.36, which was in severe pollution condition. The Pearson correlation analysis between indicators showed that TN, TP, and OM had significantly positively correlation with each other (P<0.01).