Coal mining in the Elk River Valley, British Columbia, has been ongoing since the 1880s, elevating trace element concentrations in surface and groundwater throughout the river basin, including selenium (Se) and mercury (Hg) in the transboundary Lake Koocanusa (spanning the United States and Canada). Se is an essential micronutrient that bioaccumulates in aquatic food webs and can cause toxicity at slightly elevated concentrations in egg-laying animals. Hg is a ubiquitous freshwater contaminant associated with adverse health effects, including neurotoxicity and reproductive impairment in fish and aquatic birds. We aimed to understand how exposure to Se, Hg, and other trace elements are related to biomarkers of reproductive health in fish from Lake Koocanusa.
To investigate how trace elements from Elk Valley coal mines affect fish reproductive health, we focused on biomarkers of oxidative stress (i.e., an imbalance between reactive oxygen species production and antioxidant defenses), a class of adverse effects commonly associated with metal(oid) toxicity. Specifically, we measured markers of oxidative stress (ThiobarBituric Acid Reactive Substances: TBARSs) and antioxidant defenses (SuperOxide Dismutase: SOD, CATalase: CAT, vitamins A and E), assessing the variation in concentration across different species' muscle and ovary tissues in response to trace element levels. Prolonged oxidative stress can result in cellular damage that may contribute to reproductive dysfunction. To provide a more comprehensive understanding, analyses were paired with histological assessments of reproductive dysfunction.
Preliminary findings suggest chronic Se and Hg exposure induces oxidative stress leading to impaired reproductive health. Our research highlights the ecological risks of coal mining pollution to waterways and underscores the need for ongoing monitoring and mitigation efforts. By linking the environmental stressor of coal mining to biological responses, this work provides valuable insights for resource managers and policymakers seeking to protect freshwater ecosystems from human impacts.