摘要
从滇池不同区域采集到11个表层沉积物,测定2类持久性有机污染物即多氯联苯（PCBs）和有机氯农药（OCPs）的含量,同时对沉积物中污染物的污染程度、分布特征、污染来源进行了研究。结果表明,沉积物中污染残留总体含量为DDTs〉HCHs〉PCBs,含量分别是0.26～75.20ng/g,0.63～26.0ng/g和0.64～17.7ng/g;污染物分布受人工大坝阻隔作用明显,大坝上游沉积物中污染物含量比下游高一到二个数量级。PCBs组成以三氯和五氯为主,这与我国历史上多氯联苯产品的生产和使用状况相吻合。（p,p＇-DDE＋p,p＇-DDD）/DDTs〉0.84和β-HCH/HCHs〉0.45,比值结果显示出OCPs组成以降解和残留产物为主,表明周边土壤中残留的农药是滇池沉积物中农药的主要来源。生态风险值采用加拿大环保局提出的生态风险评价框架,结果表明,滇池上游（草海）沉积物总体潜在风险较高,应当引起关注。
The Dianchi Lake is the largest lake in Yunnan Province and the sixth largest freshwater lake in China, with a reputa- tion of a Pearl Imbedded on the Plateau. It plays a very important role in agriculture and the water supply of Kunming City. However, comprehensive studies on the environmental pollution of persistent organic pollutants in the Dianchi Lake have not been carried out in recent years. In this study, we collected eleven sediment samples from the Dianchi Lake to evaluate the con- tamination and ecological risks caused by OCPs and PCBs. The contamination pattern was DDTs ~ HCHs ~ PCBs. DDTs were the most abundant pollutants, their concentrations ranging from 0.26 to 75.20 ng/g dry weight, followed by HCHs from O. 63 to 26.0 ng/g and PCBs from 0.64 to 17.07 ng/g. The concentrations of DDTs, HCHs and PCBs decreased sharply, by 1 or 2 orders of magnitude, from the upper section to the lower section because of being obstructed by the dam. The PCB homo- logue profiles were dominated by less chlorinated compounds with tri-PCBs and penta-PCBs, which are related to the historical production and use of PCBs in China. The isomer ratios of （p,p＇-DDE ＋p,p＇-DDD）/DDTs （~0.84） and β-HCH/HCHs （〉 0.45） suggested that the input of OCPs could be attributed to the heavy historical application which was preserved in agricul tural soil in adjacent areas. Some sediment samples had higher concentrations of DDT compounds and y-HCH than the stand- ards from the Canadian Environmental Quality Guideline, suggesting the OCPs in the sediments of the upper Dianchi Lake might have posed a bit high harm to the aquatic environment.
出处
《地球与环境》
CAS
CSCD
北大核心
2014年第5期625-630,共6页
Earth and Environment
基金
国家自然科学基金青年科学基金项目(41103082)
