江汉平原地下水中有机磷农药的分布特征及影响因素

为了研究江汉平原地下水中有机磷农药（OPPs）的分布特征，项目组依托该区域地下水监测场的13个监测点，于2015年6月采集了不同深度的38个地下水和4个地表水水样，通过分析其主要的水化学指标及OPPs的含量，研究江汉平原地下水中OPPs的分布特征及主要的影响因素.结果表明：研究区地下水水化学类型主要HCO₃-Ca×Mg型，并处于强还原性环境.OPPs在研究区地下水中普遍存在，采样点整体含量范围为31.5~264.5ng/L，平均值是86.5ng/L，其中检出率最高的OPPs为二嗪农和氧化乐果，含量最高是氧化乐果、甲胺磷和二嗪农，分别为54.3、32.1和27.8ng/L，无论是单种和总的OPPs含量均低于欧盟《水中农药残留标准》（EEC80/778）规定的地下水农药含量MAC标准及部分我国《生活饮用水卫生标准》（GB 5749-2006）中的农药含量限值并且对生态环境影响较小；其整体变化趋势为：垂直方向上随着深度的增加OPPs的含量逐渐增大，即：50m> 25m> 10m.水平方向上分布为：临河农田区> 中部农田区> 临河非农田区..研究区地下水中OPPs的分布受多种因素的影响，主要有：农业生产活动中使用OPPs的量、地表水与地下水的交互作用、地下水的水化学特性及生物与非生物的降解作用.

Distribution characteristics and influencing factors of organophosphorus pesticides in Jianghan plain groundwater

To investigate the distribution characteristics of organophosphorus pesticides (OPPs) in groundwater, 38groundwatersamples on the established monitoring field site with 13monitoring points and 4surface water samples were sampled in June, 2015, in Jianghan plain. According to the determination of some main chemical parameters and OPPs contents, the distribution characteristics and influencing factors of OPPs in Jianghan plain groundwater were studied. Groundwater in this area presents mainly HCO₃-Ca×Mg type with strong reducibility. OPPs were ubiquitous in our studied area ranged from 31.5 to 264.5ng/L,with the averageof 86.5ng/L.Three of higher OPPs concentrations were omethoate, methamidophos and diazinon, with the average of 54.3, 32.1 and 27.8ng/L, respectively. Not only single one but the sum of OPPs concentrations were below the MAC standard in “Groundwater Pesticide Residues in Water” (EEC80/778) andthe threshold of drinking water“Hygienic Standard for Drinking Water”(GB 5749-2006) to prove less effect on the local ecological environment. The vertical distribution of OPPs concentration followed as: 50m> 25m> 10m, while the horizontal distributionfollowing:nearby river farm area> farm area> nearby riverarea. The distribution characteristics of OPPs were also influenced by many factors, such as application amount of OPPs、the interaction between the surface water and groundwater、the fluctuation of hydrochemical parameters in groundwater and the biological and non-biological degradation.