Dept. of Soil and Water Sciences, Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
The Soil Erosion Research Station, Soil Conservation and Drainage Division, Ministry of Agriculture and Rural Development, Bet Dagan 50250, Israel.
Sci Total Environ. 2018 Jun 1;625:168-177. doi: 10.1016/j.scitotenv.2017.12.213. Epub 2017 Dec 27.
Cultivated land is a major source of pesticides, which are transported with the runoff water and eroded soil during rainfall events and pollute riverine and estuarine environments. Common ecotoxicological assessments of riverine systems are mainly based on water sampling and analysis of only the dissolved phase, and address a single pesticide's toxicological impact under laboratory conditions. A clear overview of mixtures of pesticides in the adsorbed and dissolved phases is missing, and therefore the full ecotoxicological impact is not fully addressed. The aim of this study was to characterize and quantify pesticide concentrations in both suspended sediment and dissolved phases, to provide a better understanding of pesticide-load dynamics during storm events in coastal streams in a Mediterranean climate. High-resolution sampling campaigns of seven flood events were conducted during two rainy seasons in Alexander stream, Israel. Samples of suspended sediments were separated from the solution and both media were analyzed separately for 250 pesticides. A total of 63 pesticides were detected; 18 and 16 pesticides were found solely in the suspended sediments and solution, respectively. Significant differences were observed among the pesticide groups: only 7% of herbicide, 20% of fungicide and 42% of insecticide load was transported with the suspended sediments. However, in both dissolved and adsorbed phases, a mix of pesticides was found which were graded from "mobile" to "non-mobile" with varied distribution coefficients. Diuron, and tebuconazole were frequently found in large quantities in both phases. Whereas insecticide and fungicide transport is likely governed by application time and method, the governing factor for herbicide load was the magnitude of the stream discharge. The results show a complex dynamic of pesticide load affected by excessive use of pesticides, which should be taken into consideration when designing projects to monitor riverine and estuarine water quality.
耕地是农药的主要来源，在降雨事件中，农药随地表径流和土壤侵蚀而迁移，并污染河流水体和河口环境。对河流水体进行的常见生态毒理学评估主要基于仅对溶解相的水样采集和分析，以及在实验室条件下评估单一农药的毒理学影响。对于吸附相和溶解相中的农药混合物，缺乏明确的综合概述，因此未能充分解决其全部生态毒理学影响。本研究的目的是对悬浮泥沙和溶解相中农药的浓度进行特征描述和量化，以便更好地了解地中海气候条件下沿海溪流在暴雨事件中的农药负荷动态。在以色列的亚历山大溪进行了两个雨季的七次洪水事件的高分辨率采样活动。将悬浮泥沙从溶液中分离出来，分别对两种介质进行 250 种农药的分析。共检测到 63 种农药；其中 18 种和 16 种农药仅存在于悬浮泥沙和溶液中。在农药组之间观察到显著差异：仅 7%的除草剂、20%的杀菌剂和 42%的杀虫剂负荷随悬浮泥沙迁移。然而，在溶解相和吸附相中，均发现存在混合农药，其分布系数从“移动”到“非移动”不等。敌草隆和戊唑醇在两个相中均大量频繁出现。虽然杀虫剂和杀菌剂的迁移可能受施药时间和方法的控制，但除草剂负荷的控制因素是溪流流量的大小。研究结果表明，农药负荷的动态较为复杂，受到农药过度使用的影响，在设计监测河流水体和河口水质的项目时应予以考虑。
