Research Progress on Combined Stress Effects of Secondary Water Pollution from Tailings Dam Leakage on Aquatic Organisms
Tailings dam leakage can cause secondary sudden water pollution events, imposing severe combined stress of high turbidity and heavy metal contamination on natural water bodies within a short period, threatening aquatic ecological security. Existing studies have systematically revealed the pollution characteristics and biological effects of such events, which are fundamentally distinct from natural high-turbidity water and industrial wastewater leakage. Compared with natural high-turbidity water, tailings leakage inputs finer particles with higher specific surface area, leading to more intense and prolonged turbidity stress. Meanwhile, heavy metals in tailings are more enriched than natural sediments, with higher proportions of active forms and bioavailability, causing significant bioaccumulation and toxic effects, and long-term decline in benthic community species richness. Compared with industrial wastewater leakage, tailings leakage simultaneously releases high concentrations of fine suspended solids and multiple heavy metals, forming a unique 'physical-chemical' combined stress. This synergistic effect amplifies biological toxicity through multiple pathways such as mechanical damage, light limitation, and oxidative stress, resulting in severe and often irreversible ecological damage, such as impaired fish swimming behavior and collapse of benthic community structure. Analyzing the long-term impacts of tailings leakage on aquatic ecosystems from the perspective of combined stress is helpful for providing scientific basis for emergency response and medium-to-long-term ecological risk prevention of related sudden water pollution events.