天津于桥水库流域河流表层沉积物中碳· 氮· 磷分布及污染评价

对流域内33个河流表层沉积物样点的总有机碳(TOC)、总氮(TN)和磷形态含量进行了测定,分析了沉积物中碳、氮、磷含量的分布特征及三者之间的相关性,并对于桥水库流域河流表层沉积物进行污染现状评价。结果表明:于桥水库流域河流表层沉积物TOC平均含量为0.99%,TN平均含量为0.15%,TP平均含量为1 904.93 mg/kg。相关性分析表明,沉积物TOC与TN呈极显著正相关(R2=0.794),TOC与草地面积比例呈极显著正相关,R2为0.685;TN和草地面积比例呈显著正相关(R2=0.392);TP与各种土地利用类型的相关性均不明显,但OP和Fe/Al-P与城镇居民用地面积比例呈极显著正相关,R2分别为0.664和0.698,与林地面积比例呈显著负相关,R2分别为-0.472和-0.403。有机指数和有机氮评价结果显示,有48.5%的采样点有机指数处于Ⅰ类水平,有39.4%和48.5%样点有机氮处于Ⅲ和Ⅳ类污染水平,表明于桥水库流域河流表层沉积物有机指数整体处于尚清洁及以上水平,受到有机污染程度较小,而流域内的有机氮污染相对较为严重。

Distribution Characteristics of Carbon,Nitrogen and Phosphorous of River Surface and Pollution Status Evaluation of Sediments in Yuqiao Reservoir Basin,Tianjin

The contents of total organic carbon, total nitrogen and phosphorus in the sediment samples of 33 rivers in the watershed were measured,the distribution characteristics of carbon, nitrogen and phosphorus in sediment and the correlation between the three were analyzed, and the pollution status of river surface sediments in Yuqiao Reservoir Basin was evaluated.The results showed that the average content of TOC in the surface sediments of the Yuqiao Reservoir Basin was 0.99%, the average content of TN was 0.15%, and the average content of TP was 1904.93 mg/kg.Correlation analysis showed that the sediments of TOC and TN was significantly positive correlation (R2 =0.794), TOC and the proportion of grassland area was significantly positively correlated, R2 was 0.685; there was a positive correlation between TN and grass-land area ratio (R2 =0.392).TP and various types of land use have no correlation, but OP and Fe/Al-P and the urban area proportion was significantly positively correlated, R2 were 0.664 and 0.698 respectively, and the forest area ratio had a significant negative correlation, R2 of-0.472 and -0.403 respectively.The organic index and organic nitrogen evaluation results showed that organic index of 48.5% sampling points was in theⅠ class level, there were 39.4% and 48.5% samples of organic nitrogen in Ⅲ and IV.The result showed that pollution lev-el of Yuqiao reservoir sediment basin river surface organic index as a whole was still clean and above the level of the organic pollution was less , and organic nitrogen pollution the basin was relatively serious.