Department of Applied Sciences and Technologies, Escola Superior Agrária, Instituto Politécnico de Beja, Rua Pedro Soares S/N, Apartado 6155, 7800-295, Beja, Portugal,
Environ Geochem Health. 2014 Apr;36(2):209-23. doi: 10.1007/s10653-013-9559-2. Epub 2013 Aug 29.
In order to study the pollution of an aquatic ecosystem, it is necessary to analyze not only the levels of chemical pollutants in water, but also those accumulated in the sediment matrix, as well as to assess its ecotoxicological status. The Alqueva reservoir, the largest artificial lake in Europe, was chosen as case study as it constitutes the most important water supply source in southern Portugal. It is located in the Guadiana River Basin, in a semi-arid region with high levels of water scarcity and where agriculture is one of the main activities. The evaluation of sediments comprised: (1) physical and chemical analysis (grain size, pH, organic matter, nitrogen, phosphorus); (2) potentially toxic trace elements (Cu, As, Pb, Cr, Cd, Zn and Ni); and (3) ecotoxicological evaluation with Vibrio fischeri, Thamnocephalus platyurus, Daphnia magna, and Heterocypris incongruens. Total trace element concentrations indicated that As, Cd, and Pb surpassed the Canadian levels for the protection of aquatic life, in most of Alqueva's sites. The results of the toxicity assessment showed that some locations induced acute and chronic toxicity in the species used. Further, the H. incongruens was the most sensitive species as far as the contamination found in the sediment is concerned, followed by the bacteria V. fischeri. This integrative approach, together with the water column quality assessment, allowed a comprehensive evaluation of the environmental quality of this strongly modified water body and will allow the implementation of remediation strategies to obtain a good ecological potential as proposed in the Water Framework Directive.
为了研究水生生态系统的污染，不仅需要分析水中化学污染物的水平，还需要分析沉积物基质中积累的污染物水平，并评估其生态毒理学状况。阿尔库韦拉水库是欧洲最大的人工湖，被选为案例研究，因为它是葡萄牙南部最重要的供水来源。它位于瓜迪亚纳河流域，在一个半干旱地区，水资源极度短缺，农业是主要活动之一。沉积物的评估包括：（1）物理和化学分析（粒度、pH 值、有机质、氮、磷）；（2）潜在毒性微量元素（Cu、As、Pb、Cr、Cd、Zn 和 Ni）；（3）采用发光细菌（Vibrio fischeri）、扁蜉（Thamnocephalus platyurus）、大型水蚤（Daphnia magna）和杂色异足轮虫（Heterocypris incongruens）进行生态毒理学评价。总微量元素浓度表明，在阿尔库韦拉的大部分地区，As、Cd 和 Pb 超过了加拿大保护水生生物的水平。毒性评估结果表明，一些地点对所用物种产生了急性和慢性毒性。此外，就沉积物中发现的污染而言，杂色异足轮虫是最敏感的物种，其次是细菌发光杆菌。这种综合方法，结合水柱质量评估，对这个受强烈改造的水体的环境质量进行了全面评估，并将允许实施修复策略，以获得如《水框架指令》所提议的良好生态潜力。
