Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, 46980, Paterna, Spain; Laboratorio Nacional de Referencia Del Agua, Universidad Regional Amazónica Ikiam, Tena, 150150, Ecuador.
Instituto de Ciencias Del Mar y Limnología-Estación El Carmen, Universidad Nacional Autónoma de México, Ciudad Del Carmen, 24157, Mexico.
Chemosphere. 2023 Oct;337:139286. doi: 10.1016/j.chemosphere.2023.139286. Epub 2023 Jun 26.
The Ecuadorian Amazon has experienced a significant land use change due to the demographic increase and the expansion of the agricultural frontier. Such changes in land use have been associated to water pollution problems, including the emission of untreated urban wastewater and pesticides. Here we provide the first report on the influence of urbanization and intensive agriculture expansion on water quality parameters, pesticide contamination and the ecological status of Amazonian freshwater ecosystems of Ecuador. We monitored 19 water quality parameters, 27 pesticides, and the macroinvertebrate community in 40 sampling locations of the Napo River basin (northern Ecuador), including a nature conservation reserve and sites in areas influenced by African palm oil production, corn production and urbanization. The ecological risks of pesticides were assessed using a probabilistic approach based on species sensitivity distributions. The results of our study show that urban areas and areas dominated by African palm oil production have a significant influence on water quality parameters, affecting macroinvertebrate communities and biomonitoring indices. Pesticide residues were detected in all sampling sites, with carbendazim, azoxystrobin, diazinon, propiconazole and imidacloprid showing the largest prevalence (>80% of the samples). We found a significant effect of land use on water pesticide contamination, with residues of organophosphate insecticides correlating with African palm oil production and some fungicides with urban areas. The pesticide risk assessment indicated organophosphate insecticides (ethion, chlorpyrifos, azinphos-methyl, profenofos and prothiophos) and imidacloprid as the compounds posing the largest ecotoxicological hazard, with pesticide mixtures potentially affecting up to 26-29% of aquatic species. Ecological risks of organophosphate insecticides were more likely to occur in rivers surrounded by African palm oil plantations, while imidacloprid risks were identified in corn crop areas as well as in natural areas. Future investigations are needed to clarify the sources of imidacloprid contamination and to assess its effects for Amazonian freshwater ecosystems.
厄瓜多尔亚马逊地区由于人口增长和农业前沿的扩张，经历了显著的土地利用变化。这种土地利用的变化与水污染问题有关，包括未经处理的城市废水和农药的排放。在这里，我们首次报告了城市化和集约化农业扩张对厄瓜多尔亚马逊地区淡水生态系统水质参数、农药污染和生态状况的影响。我们监测了纳波河流域（厄瓜多尔北部）40 个采样点的 19 个水质参数、27 种农药和大型底栖无脊椎动物群落，包括一个自然保护区以及受油棕生产、玉米生产和城市化影响的地区。我们使用基于物种敏感性分布的概率方法评估了农药的生态风险。我们的研究结果表明，城市地区和油棕生产主导地区对水质参数有显著影响，影响大型底栖无脊椎动物群落和生物监测指数。所有采样点均检测到农药残留，其中多菌灵、唑菌酯、二嗪磷、丙环唑和吡虫啉的检出率最高（>80%的样本）。我们发现土地利用对水农药污染有显著影响，有机磷杀虫剂残留与油棕生产有关，一些杀菌剂与城市地区有关。农药风险评估表明，有机磷杀虫剂（乙硫磷、毒死蜱、甲拌磷、丙溴磷和丙硫磷）和吡虫啉是对生态系统危害最大的化合物，农药混合物可能对多达 26-29%的水生物种产生影响。有机磷杀虫剂的生态风险更可能发生在油棕种植园环绕的河流中，而吡虫啉的风险则出现在玉米种植区以及自然地区。需要进一步的调查来澄清吡虫啉污染的来源，并评估其对亚马逊淡水生态系统的影响。
