长江三峡库区库尾区域25种有机氯残留污染研究

Study on Residual Pollution of 25 Organochlorines in the Tail Area of the Three Gorges Reservoir Area of the Yangtze Rive

深入探究三峡库区库尾水体中有机氯的含量,建立了液液萃取GC-ECD法测定水体中25种OCPs的方法,相关系数R值均在0.9991以上,检出限为0.0002~0.0013μg/L,较GB 7492-87、HJ699-2014、EPA method (8081B)等测定OCPs的方法检出限降低了10~100倍以上。对水样在液液萃取前处理时的pH值、萃取次数、萃取溶剂体积进行了探索,确立了萃取pH为5~9,萃取次数为1次,250毫升水样萃取溶剂体积25毫升为最优条件。运用该方法于2021年12月至2023年1月对三峡库区库尾区域的OCPs进行了较长时间监测研究,水体中共检测出9种OCPs,∑HCHs含量范围为0.67~9.66 ng/L,平均值为8.49 ng/L,∑DDTs含量范围为nd~1.68 ng/L,平均值为0.78 ng/L,∑OCPs含量范围为1.63~23.9 ng/L,平均值为15.8 ng/L。结果表明三峡库区库尾区域水体中有机氯含量总体较低,水体中浓度较高的为HCHs,通过比值分析得出大气远距离传输是HCHs物质的主要来源。

In order to deeply explore the content of organic chlorine in the tail water of the Three Gorges Reservoir,a liquid-liquid extraction GC-ECD method was established for the determination of 25 OCPs in water,the correlation coefficient R value was above 0.9991,and the detection limit was 0.0002~0.0013μg L,which is 10 to 100 times lower than the detection limit of methods such as GB 7492-87,HJ699-2014,and EPA method(8081B)for the determination of OCPs.The pH value,extraction times,and extraction solvent volume of water samples before liquid-liquid extraction were explored.The optimal extraction conditions were established as follows:the extraction pH was 5 to 9,the extraction times were 1,and the extraction solvent volume of 250 ml of water samples was 25 ml.Using this method,a long-term monitoring study was conducted on OCPs in the tail area of the Three Gorges Reservoir from December 2021 to January 2023,total of 9 OCPs were detected in the water body,with a content range ofΣHCHs ranging from 0.67 to 9.66 ng L,an average of 8.49 ng L,a content range ofΣDDTs ranging from nd to 1.68 ng L,an average of 0.78 ng L,and a content range ofΣOCPs ranging from 1.63 to 23.9 ng L,an average of 15.8 ng L.The results show that the organic chlorine content in the water body at the tail of the Three Gorges Reservoir is generally low,and the higher concentration in the water body is HCHs,through ratio analysis,it is concluded that atmospheric long-distance transport is the main source of HCHs.