Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden; Institute for Environmental Sciences, University of Koblenz-Landau, Fortstrasse 7, 76829 Landau, Palatinate, Germany.
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
Sci Total Environ. 2014 Jun 15;484:84-91. doi: 10.1016/j.scitotenv.2014.03.015. Epub 2014 Mar 29.
The European Water Framework Directive requires surface water bodies to have a good chemical and ecological status. Although relatively few pesticides are included in the list of priority pollutants, they pose, due to their intrinsic biological activity, a significant risk for the integrity of aquatic ecosystems. In this context, the pesticide (up to 128 pesticides including some transformation products) exposure pattern in four agricultural streams and two rivers was determined from 2002 to 2011 under the umbrella of the Swedish national monitoring program employing time-proportional and grab sampling strategies, respectively. After transforming the measured pesticide concentrations into toxic units, the European Uniform Principles for algae (chronic), invertebrates and fish (both acute), which are partly employed as benchmark for pesticide regulation, were only occasionally (<2%) exceeded. Moreover, this evaluation showed no long-term trends over the years. However, recent publications suggested that those thresholds are not protective for ecosystem structure and function, indicating a risk of up to 20% and 35% of the samples from the agricultural streams and the rivers, respectively. Moreover, the monitoring data show a continuous but rather low toxic potential of pesticides for all three trophic levels throughout the year, which suggests pesticides as an evolutionary force in agriculturally impacted aquatic ecosystems. However, the flow-triggered sampling, which was implemented as an additional sampling strategy in one of the agricultural streams starting in 2006, displayed an up to 7-fold underestimation of the maximum concentration in terms of toxic units for daphnids and fish during run-off events. The present study thus underpins that the optimal sampling design for pesticide monitoring strongly depends on its overall purpose. If the long-term exposure pattern is of concern a time-proportional composite sampling strategy is recommended, while for an assessment of peak exposures a flow-event-triggered high-resolution sampling strategy is superior.
《欧盟水框架指令》要求地表水具有良好的化学和生态状况。尽管相对较少的农药被列入优先污染物清单，但由于其内在的生物活性，它们对水生生态系统的完整性构成了重大风险。在这种情况下，瑞典国家监测计划在 2002 年至 2011 年期间采用时间比例和抓取采样策略，分别确定了四个农业溪流和两条河流中的农药（包括一些转化产物在内的多达 128 种农药）暴露模式。在将测量的农药浓度转化为毒性单位后，采用部分作为农药监管基准的欧洲藻类（慢性）、无脊椎动物和鱼类（急性）统一原则，偶尔（<2%）超标。此外，这项评估在多年内没有显示出长期趋势。然而，最近的出版物表明，这些阈值对生态系统结构和功能没有保护作用，表明农业溪流和河流的样本分别有高达 20%和 35%存在风险。此外，监测数据显示，全年所有三个营养级别的农药都具有持续但相当低的毒性潜力，这表明农药是受农业影响的水生生态系统中的一种进化力量。然而，从 2006 年开始在一个农业溪流中实施的作为附加采样策略的流量触发采样，在径流事件中，对水蚤和鱼类的毒性单位最大浓度的估计值低估了 7 倍。因此，本研究表明，农药监测的最佳采样设计强烈取决于其总体目的。如果关注的是长期暴露模式，则建议采用时间比例复合采样策略，而对于评估峰值暴露，则采用流量事件触发的高分辨率采样策略更为优越。
