中文摘要：

通过对广西北部湾典型人海河流南流江上、中、下游城市河段表层沉积物碳、氮、磷的调查分析，揭示其富集特征，并利用单因子直接评价法、内梅罗综合污染指数法与有机指数法对沉积物污染状况进行了评价。结果表明：（1）七游河段沉积物中总有机碳（TOC）、总碳（TC）、总氮（TN）、总磷（TP）平均质量浓度分别为9．2、21．4、1．6、0．126g／kg，中游河段分别为13．9、23．8、1．1、0．083g／kg，下游河段分别为9．8、12．6、0．9、0．082g／kg。（2）从Pearson相关分析可知，TP、TN、TC、总无机碳（TIC）两两间均具有显著相关性，表明碳、氮、磷的来源具有一定的同源性。（3）从单因子评价结果看，TN污染最严重；从内梅罗综合污染指数来看，中游河段污染最严重，上游次之，下游最优；从有机指数来看，3个城市河段总体均处于Ⅲ级（高营养）水平。

英文摘要：

Based on the survey of surface sediment nutrients （C,N,P） in urban parts along upriver to downriver of a typical river bounding for sea in Beibu Gulf, namely Nanliujiang River, enrichment characteristics were analyzed. The pollution status was assessed by using single-factor index, Nemerow index and organic index. Results showed that ： （ 1 ） the mass concentrations of TOC, TC, TN, TP in upriver were 9.2,21.4,1.6,0.126 g/kg, respectively ; those in midriver 13.9,23.8,1.1,0.083 g/kg, respectively; those in downriver 9.8,12.6,0.9,0.082 g/kg,respectively. （2） Based on the Pearson correlation analysis, TP, TN, TC and TIC were all significantly correlated, indicating that car- bon,nitrogen and phosphorus might come from the same sources. （3） Single-factor index showed that TN was the most polluted factor; as Nemerow index showed,midriver was the most polluted parts,while upriver second and downriver third; from organic index,the urban parts of Nanliujiang River were at high level nutrition pollution （Level Ⅲ）.