太湖流域水源地有机氯农药分布特征与生态风险评价

Distribution characteristics and ecological risk assessment of organochlorine pesticides in water sources of Taihu Lake Basin

为系统了解太湖流域主要水源地有机氯农药(OCPs)污染情况,于2012年3月和6月采集太湖流域主要水源地水相、悬浮颗粒物和沉积物样品,并利用气相色谱(GC)—质谱(MS)联用仪对水源地OCPs的浓度水平进行监测分析。结果表明,3月水相和悬浮颗粒物中OCPs的质量浓度分别为4.03~18.70ng/L、ND(未检出)~27.60ng/g,高于6月的0.23~1.57ng/L、1.06~5.05ng/g。3月沉积物中仅有Y3采样点检出OCPs,而6月各采样点均有检出。6月水相中Y5、Y7和Y10采样点以α-六六六(α-HCH)为主,Y3和Y8采样点以γ-六六六(γ-HCH)为主,其余采样点均为β-六六六(β-HCH)占绝对优势;悬浮颗粒物中γ-HCH、α-HCH构成六六六(HCHs)的主要物质,而稳定性较高的β-HCH浓度却很低。与国内外研究比较,太湖流域水源地OCPs污染水平较低。大部分悬浮颗粒物中OCPs污染低于风险评价高值(ER-M),部分采样点高于风险评价低值(ER-L),表明存在一定的生态风险,需加强相关方面的防治工作。沉积物中污染物的浓度均低于ER-L,表明太湖流域沉积物的污染程度较低,在安全生态风险范围内。

In order to understand the pollution of organochlorine pesticides （OCPs） in the main water sources of Taihu Lake Basin,the water phase,suspended particulate matter and sediment samples of the main water sources in Taihu Lake Basin were collected in March and June 2012. The samples were analyzed by gas ehromatograph（GC）- mass spectrometer（MS）. The results showed that the concentrations of OCPs in water phase and suspended particu- late matter were 4.03-18.70 ng/L and ND （Not detected）-27.6 ng/g in March, respectively,which were higher than those in June（0.23-1.57 ng/L,1.06-5.05 ng/g）. The OCPs of sediments was detected only in Y3 sampling site in March. However,the OCPs were detected in each sampling site in June. a-HCH was the dominant HCHs in water phase in Y5, Y7 and Y10 sampling site in June,γ-HCH was the the dominant HCHs in Y3 and Y8 sampling site,and β-HCH was dominant in the other sampling sites. γ-HCH and α-HCH were the main components of HCHs in suspen- ded particles,while the concentration of β-HCH with high stability was low. Compared with the domestic and foreign researches, the pollution level of OCPs in the water sources of Taihu Lake Basin was low. The concentrations of OCPs in suspended particles were lower than ER-M in most of the sampling points, but were higher than ER-L in some sam- pling sites,indicating that there was a certain ecological risk, so it was necessary to strengthen the relevant prevention and control work. The concentrations of OCPs in sediments were lower than ER-L,indicating that the pollution level of sediments in Taihu Lake Basin was low,and was within the safe range of ecological risk.