内蒙古呼伦湖沉积物营养元素分布及环境污染评价

Distribution of nutrient elements and environmental pollution assessment in sediment of Hulun Lake,Inner Mongolia

对呼伦湖各采样点表层沉积物营养元素(TN、TP和TOC)的分布特征及相互关系进行了分析,并对表层沉积物进行了营养元素的环境评价和重金属的地积累指数评价。结果表明:新开河、乌尔逊河及克鲁伦河入湖点(A10、F9、I2)营养元素的含量均低于其它采样点,且TOC与TN和TP的环境行为近似,说明TN和TP的沉积与生物有机质的沉积相伴随;呼伦湖沉积物碳氮比的均值约为10.2,说明内、外源有机质基本达到平衡状态。通过对沉积物的环境污染评价发现,呼伦湖沉积物有机污染较轻,仍处于较清洁状态,但有机氮的污染程度较为严重;地积累指数评价显示,主要污染元素为Cd和As,Hg、Cu和Zn属于无污染状态。

The distribution and inter relationship of nutrient elements （TN,TP and TOC） in surface sediment of Hunlun Lake were analyzed. The environmental evaluation of nutrient elements and geo - accumulation evaluation of heavy metals in the sediment were also determined. The results showed that the concentrating of nutrients at the entrance of Xinkai river,Wuerxun river and Kelulun river were less than other samples. The environmental behavior of TOC was as similar as TN＇s and TP＇s. This indicated that the deposition of TN and TP were accompanied with organic matters＇. In addition,the average value of C/N was about 10. 2,which illustrated that it reached balance between extraneous sources and endogenous sources. Through evaluating the sediments,it showed that Hulun Lake was light polluted by organic matter,but severe polluted by organic nitrogen. The results of index of geo - accumulation（Igeo） evaluation showed that the dominant contaminant was Cd,and the second was As. There were no pollution caused by Hg、Cu、Zn.