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<p>The rupture of mining dams, such as the incident in Mariana, Minas Gerais, poses a significant threat to aquatic biodiversity, mainly due to water contamination with heavy metals. These metals can harm freshwater organisms by accumulating in various organs and disrupting multiple physiological processes, including reproduction. We examined the histometric and histological effects of exposure to water contaminated by a dam failure from the Gualaxo do Norte River in Mariana, Minas Gerais, on the gonads of female <i>Astyanax lacustris</i>. Specimens were divided into two groups: a control group kept in dechlorinated tap water and a treatment group exposed to river water for 15&#xa0;days. Histometric and histological analyses of the gonads were conducted to assess the potential impacts of the procedures on gametogenesis. Results showed reduced diameters of vitellogenic oocytes, a higher proportion of oocytes in early developmental stages, and an increased occurrence of follicular atresia in the treatment group, indicating impaired oocyte maturation. These findings highlight the possible negative effects of exposure to water contaminated with mining tailings on the reproductive health of the species. This study underscores the importance of ongoing monitoring and management of the ecotoxicological impacts of heavy metal contamination in aquatic environments affected by environmental disasters.</p>

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Effects of the exposition to waters from the Doce River basin (Minas Gerais, Brazil) on the gametogenesis of females of Astyanax lacustris (Characiformes: Acestrorhamphidae) after the Fundão dam collapse

  • 期刊论文

  • 发表日期：

    2025年10月6日

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  • Maria Eduarda Moura de Morais,
  • Alessandro Loureiro Paschoalini,
  • Angélica da Silva Vasconcellos,
  • João Victor Saraiva Raimondi Lopes

摘要

The rupture of mining dams, such as the incident in Mariana, Minas Gerais, poses a significant threat to aquatic biodiversity, mainly due to water contamination with heavy metals. These metals can harm freshwater organisms by accumulating in various organs and disrupting multiple physiological processes, including reproduction. We examined the histometric and histological effects of exposure to water contaminated by a dam failure from the Gualaxo do Norte River in Mariana, Minas Gerais, on the gonads of female Astyanax lacustris. Specimens were divided into two groups: a control group kept in dechlorinated tap water and a treatment group exposed to river water for 15 days. Histometric and histological analyses of the gonads were conducted to assess the potential impacts of the procedures on gametogenesis. Results showed reduced diameters of vitellogenic oocytes, a higher proportion of oocytes in early developmental stages, and an increased occurrence of follicular atresia in the treatment group, indicating impaired oocyte maturation. These findings highlight the possible negative effects of exposure to water contaminated with mining tailings on the reproductive health of the species. This study underscores the importance of ongoing monitoring and management of the ecotoxicological impacts of heavy metal contamination in aquatic environments affected by environmental disasters.