Aarhus University, Department of Bioscience, Vejlsøvej 25, 8600 Silkeborg, Denmark.
University of Copenhagen, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark.
Sci Total Environ. 2016 Jan 15;542(Pt A):12-21. doi: 10.1016/j.scitotenv.2015.10.062. Epub 2015 Oct 27.
Many tropical countries contain a high density of protected ecosystems, and these may often be bordered by intensive agricultural systems. We investigated the chemical and ecological status of a stream connecting an area with conventional rice production and a downstream protected nature reserve; Mata Redonda. Three sites were sampled: 1) an upstream control, 2) in the rice production area and 3) a downstream site in Mata Redonda. We sampled benthic macroinvertebrates and pesticides in water and sediments along with supporting physical and chemical data. Pesticide concentrations in water exceeded current safety thresholds at sites 2 and 3, especially during the rainy season, and sediment associated pesticide concentrations exceeded current safety thresholds in three of six samples. Importantly, the highest predicted pesticide toxicity in sediments was observed at site 3 in the Mata Redonda confirming that the nature reserve received critical levels of pesticide pollution from upstream sections. The currently used macroinvertebrate index in Costa Rica (BMWP-CR) and an adjusted version of the SPecies At Risk index (SPEAR) were not significantly correlated to any measure of anthropogenic stress, but the Average Score Per Taxon (ASPT) index was significantly correlated with the predicted pesticide toxicity (sumTUD.magna), oxygen concentrations and substrate composition. Our results suggest that pesticide pollution was likely involved in the impairment of the ecological status of the sampling sites, including site 3 in Mata Redonda. Based on our results, we give guidance to biomonitoring in Costa Rica and call for increased focus on pesticide transport from agricultural regions to protected areas.
许多热带国家都有高密度的保护生态系统，这些生态系统通常与集约农业系统相邻。我们调查了一条连接常规水稻种植区和下游自然保护区（Mata Redonda）的溪流的化学和生态状况。在三个地点进行了采样：1）上游对照点，2）水稻种植区，以及 3）Mata Redonda 的下游点。我们在水中和沉积物中采样了底栖大型无脊椎动物和农药，同时还采集了支持性的物理和化学数据。在站点 2 和 3，水中的农药浓度超过了当前的安全阈值，尤其是在雨季，而在 6 个沉积物样本中有 3 个样本中的农药浓度超过了当前的安全阈值。重要的是，在 Mata Redonda 的第 3 个地点观察到了沉积物中最高的预测农药毒性，这证实了自然保护区从上游地区接收到了关键水平的农药污染。哥斯达黎加目前使用的大型无脊椎动物指数（BMWP-CR）和调整后的风险物种指数（SPEAR）与任何人为压力指标均无显著相关性，但每个分类群的平均得分指数（ASPT）与预测的农药毒性（sumTUD.magna）、氧浓度和基质组成显著相关。我们的研究结果表明，农药污染可能是导致采样点生态状况受损的原因之一，包括 Mata Redonda 的第 3 个地点。根据我们的研究结果，我们为哥斯达黎加的生物监测提供了指导，并呼吁更加关注从农业区向保护区转移的农药运输问题。
