Laboratório de Mamíferos Aquáticos e Bioindicadores "Profª Izabel Gurgel", Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Oceanografia, Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Rio de Janeiro, Brazil.
Laboratório de Mamíferos Aquáticos e Bioindicadores "Profª Izabel Gurgel", Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Oceanografia, Faculdade de Oceanografia, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524, Rio de Janeiro, Brazil.
Sci Total Environ. 2022 Jan 15;804:150196. doi: 10.1016/j.scitotenv.2021.150196. Epub 2021 Sep 9.
One of the largest environmental disasters worldwide occurred on November 5th 2015, when the Fundão dam collapsed in Mariana (Minas Gerais State, Southeast Brazil). The tailing mud flooded the Doce River basin and reached the sea in the coast of Espírito Santo State (ES), Southeast Brazil. This coastal region is the habitat of the most isolated population of franciscana dolphins (Pontoporia blainvillei), with the lowest populational census and lowest genetic diversity in Franciscana Management Area Ia (FMA Ia) - 18° 25'S and 21° 17'S. This study aimed to assess the bioaccumulation of trace-elements (As, Cd, Cu, Fe, Hg, Mn, and Zn) in muscle, liver and kidney of franciscana dolphins collected near the Doce River's mouth before (n = 32) and after (n = 19) the tailing mud reached the sea. The Generalized Additive Model (GAM) showed increasing temporal trends of Hg and Zn in muscle and liver after the dam failure, probably related to higher concentrations and bioavailability in the water column and sediments from the Doce River. Declining trends were found for As and Cu muscular and hepatic concentrations and Fe concentrations in kidney due to their lower bioavailability after the disaster, caused by association with tailings mud trapped in the riverbanks and suspended particulate material. Additionally, higher As and Hg concentrations found in the first period of sampling may be due to historical contamination by mining activities. The full extent of the impacts caused by the Fundão dam failure is still unknown. However, due to their rapid increase and remobilization process, toxic effects can be induced in the biota by these elements. Elements' bioaccumulation in this study contributes to the knowledge of franciscana dolphins from FMA Ia. Considering the conservation concern regarding this franciscana population and its scarce knowledge, the impact of this disaster can be alarming for species conservation.
2015 年 11 月 5 日，巴西东南部米纳斯吉拉斯州马里亚纳市的范登大坝决堤，这是全球最大的环境灾难之一。尾矿泥涌入多西河盆地，并在巴西东南沿海的圣埃斯皮里图州（ES）入海。该沿海地区是孤立的弗氏圆海豚（Pontoporia blainvillei）种群的栖息地，该种群在弗朗西萨纳管理区 Ia（FMA Ia）的种群数量最少，遗传多样性最低 - 南纬 18°25'至 21°17'。本研究旨在评估多西河口附近采集的弗氏圆海豚肌肉、肝脏和肾脏中痕量元素（As、Cd、Cu、Fe、Hg、Mn 和 Zn）的生物累积情况，采样时间分别为尾矿泥入海前（n=32）和入海后（n=19）。广义加性模型（GAM）显示，大坝决堤后，肌肉和肝脏中 Hg 和 Zn 的时间趋势呈上升趋势，这可能与多西河河水和沉积物中更高的浓度和生物可利用性有关。由于尾矿泥在河岸和悬浮颗粒物中被捕获，其生物可利用性降低，肌肉和肝脏中 As 和 Cu 的浓度以及肾脏中 Fe 的浓度呈下降趋势。由于采矿业的历史污染，采样初期发现的 As 和 Hg 浓度较高。范登大坝决堤造成的影响的全部程度尚不清楚。然而，由于这些元素的快速增加和再移动过程，它们可能会对生物群产生毒性影响。本研究中元素的生物累积有助于了解 FMA Ia 地区的弗氏圆海豚。考虑到该弗氏圆海豚种群的保护问题及其知之甚少，这场灾难对物种保护的影响可能令人震惊。
