巢湖沉积物OPs和SPs的生态风险评价

Ecological risk evaluation of organophosphate pesticides and synthetic pyrethroids insecticides in surface sediment from Chaohu Lake

为了认识水生环境中当前使用的有机磷农药（OPs）和拟除虫菊酯杀虫剂（SPs）的赋存、来源和生态风险,文章利用固相萃取（solid-phase extraction,SPE）-气相色谱-质谱（gas chromatography-mass spectrometry,GC-MS）技术分析了巢湖表层沉积物中10种SPs和12种OPs的浓度,通过与国内外相关研究结果比较,明确了这些污染物在巢湖流域的污染现状,并结合物种敏感性分布模型（species sensitivity distribution,SSD）评价了表层沉积物中浓度较高的苄氯菊酯和敌敌畏生态风险。结果表明：巢湖表层沉积物中SPs和OPs质量比范围分别为0.08-2.95ng/g和0.09-1.72ng/g,并呈现出西半湖高、东半湖低的空间分布特点。其中苄氯菊酯和敌敌畏分别是SPs和OPs最重要的组成成分,占各自总质量比的44%和47%;与国内外其他地区表层沉积物中报道的数值比较,巢湖表层沉积物中SPs质量比处于较低水平。SSD模型评价结果显示巢湖表层沉积物中苄氯菊酯生态风险较低,但敌敌畏却存在极大的生态安全风险,因此需要采取相应的措施减小OPs对当地水生生态系统的影响。

In order to understand the occurrence, sources and ecological risk of current-use organophosphate pesticides（OPs） and synthetic pyrethroids insecticides（SPs）, twelve kinds of OPs and ten kinds of SPs in surface sediments collected from Chaohu Lake were determined using solid-phase extraction （SPE） combined with gas chromatography-mass spectrometry（GC-MS）. The pollution status of Chaohu Lake by SPs and OPs was investigated by comparing with the results of global and national studies. Permethrin and dichlorvos were selected as model contaminants to evaluate the potential ecological risks based upon species sensitivity distribution（SSD）. The results indicated that the total concentrations were at 0.08-2.95 ng/g for SPs and 0.09-1.72 ng/g for OPs, respectively, and higher concentrations of SPs and OPs were observed in the samples from western lake comparing with eastern lake. Permethrin was the most predominant component of SPs, accounting for 44 % of the total SPs concentration, while dichlorvos was the largest contributor to the total OPs concentration, accounting for 47%. In total, Chaohu Lake was weakly contaminated with SPs when the residual concentrations of SPs were compared to the results of the previous studies. The results of SSD also suggested that Chaohu Lake exposed low ecological risk to permethrin, but extremely high risk to dichlorvos. Therefore, relevant measures should be taken to reduce the effect of OPs on the local aquatic ecosystem.