Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 519, Vitória CEP 29075-910, ES, Brazil.
Universidade Federal do Espírito Santo, Av. Fernando Ferrari, 519, Vitória CEP 29075-910, ES, Brazil.
Sci Total Environ. 2021 Nov 20;796:148965. doi: 10.1016/j.scitotenv.2021.148965. Epub 2021 Jul 16.
Freshwater biodiversity has been impacted by several stressors such as eutrophication, turbidity and metals. Besides these frequent impacts, large-scale accidents occasionally affect aquatic systems, input an intense load of contaminants to the water bodies, as in the case of the Fundão tailing dam collapse (Brazil), which launched millions of meters cubic of iron ore tailing in the Doce River Basin. Our aim in this study was to assess how much stress the environmental conditions of lentic and lotic environments in the lower region of this basin impact the periphytic community. In addition, we intend to verify whether the limits of changes of the periphytic communities agreed with Brazilian legislation for the protection of aquatic life. For that, monthly samplings were carried out in seven sampling stations in lentic environments and five in lotic environments, including the Doce River channel, between October/2018 and March/2021 (except in October/2019). Concentrations of metals (iron, aluminum, manganese and chromium), total nitrogen, total phosphorus, conductivity, and suspended particulate material were determined. The periphytic community was collected from natural substrates (macrophytes or pebbles) and quantified by the sedimentation chamber method. From these data, thresholds of concentrations of variables that caused changes in periphytic communities were determined by the Threshold Indicator Taxa ANalysis (TITAN). We concluded that evidence of chronic impact of iron ore tailing should be revealed and that the standards established by Brazilian legislation may be incompatible with the protection of aquatic life. Moreover, we found that the Doce River mouth and surrounding environments were the most stressful environments for the periphytic communities.
淡水生物多样性受到多种胁迫因素的影响，如富营养化、浑浊度和金属。除了这些常见的影响外，大规模事故偶尔也会影响水生系统，将大量污染物输入水体，就像 Fundão 尾矿坝溃坝（巴西）那样，导致数百万立方米的铁矿石尾矿涌入 Doce 河流域。我们在这项研究中的目的是评估该流域下游的静水和流水环境的条件对周丛生物群落造成了多大的压力。此外，我们还希望验证周丛生物群落的变化极限是否符合巴西保护水生生物的立法。为此，我们于 2018 年 10 月至 2021 年 3 月（2019 年 10 月除外）期间每月在 7 个静水采样站和 5 个流水采样站（包括 Doce 河河道）进行采样。在这些站点，我们测定了金属（铁、铝、锰和铬）、总氮、总磷、电导率和悬浮颗粒物的浓度。周丛生物群落是从自然基质（大型藻类或鹅卵石）中采集的，并通过沉淀室法进行定量。根据这些数据，我们通过阈值指示物种分析（TITAN）确定了引起周丛生物群落变化的变量浓度阈值。我们得出的结论是，应该揭示铁矿石尾矿的慢性影响证据，并且巴西立法规定的标准可能与保护水生生物不相容。此外，我们发现 Doce 河口及其周边环境是对周丛生物群落压力最大的环境。
