Laboratório de Ictiologia Aplicada - LabPeixe, Universidade Vila Velha, Complexo Biopráticas - Av. José Dantas de Melo, 21, Boa Vista, Zip Code 29102-770 Vila Velha, ES, Brazil.
Laboratório de Ictiologia Aplicada - LabPeixe, Universidade Vila Velha, Complexo Biopráticas - Av. José Dantas de Melo, 21, Boa Vista, Zip Code 29102-770 Vila Velha, ES, Brazil.
Sci Total Environ. 2020 Sep 20;736:139644. doi: 10.1016/j.scitotenv.2020.139644. Epub 2020 May 25.
In 2015, after the Fundão dam failure, in Minas Gerais State, Brazil, around 50 million cubic meters of sludge from iron mining tailings were discharged into the Doce River. After the dam collapse, surpassing concentrations of metals were observed in the river sediment, which could be harmful to aquatic organisms, including the fishes. The present study aimed to evaluate the toxic effects of both elutriate and water, collected from the Doce River, on Astyanax lacustris three years after the dam failure. A bioassay was carried out through subchronic exposure to Doce River water (E0) and three elutriate concentrations (10, 50 and 100%). Biochemical analyses (CAT, GST, AChE), metal bioaccumulation assays and calculation of the integrated biomarker response index, version 2 (IBRv2) were performed. The outcomes uncovered deleterious consequences on organisms exposed to E0, with AChE inhibition and bioaccumulation of Fe and Mn in both liver and gills. IBRv2 values were more elevated in fishes exposed to E0 for all tissues. Thus, the elutriate was not harmful for the assessed fishes, since complexing agents presented in the sediment, such as goethite and hematite, may have triggered metals' chelation. In this scenario, the elutriate may have acted as a protective agent for the subjected organisms, unlike the Doce River waters, in which contaminants were proven to be hazardous for the aquatic biota.
2015 年，巴西米纳斯吉拉斯州丰当大坝溃坝后，约 5000 万立方米的铁矿尾矿淤泥被排入多西河。大坝溃决后，河底沉积物中观察到金属浓度超标，这可能对包括鱼类在内的水生生物造成危害。本研究旨在评估丰当大坝溃坝三年后，多西河水体和底泥浸出液对亚西阿诺斯湖脂鲤的毒性影响。通过亚慢性暴露于多西河河水（E0）和三种底泥浸出液浓度（10、50 和 100%）进行生物测定。进行了生化分析（CAT、GST、AChE）、金属生物累积测定和综合生物标志物响应指数（IBRv2）的计算。结果表明，暴露于 E0 的生物受到了有害影响，AChE 抑制以及肝脏和鳃中铁和锰的生物累积。对于暴露于 E0 的所有组织，IBRv2 值均升高。因此，底泥浸出液对评估的鱼类没有危害，因为沉积物中存在的络合剂，如针铁矿和赤铁矿，可能引发了金属的螯合。在这种情况下，底泥浸出液可能对受试生物起到了保护作用，而多西河河水则被证明对水生生物群具有危害性。
