Tidigare gruvdrifts inverkan på metallföroreningar och bentiska makroevertebrater i litoralsediment: Utvärdering av rumsliga mönster och ekologiska effecter

Mining activities produce waste, and under certain conditions, metals in tailings can be remobilized and leach into nearby environments. Previous studies have documented elevated metal concentrations in water bodies and sediments connected to mining sites. Littoral sediments, being ecologically diverse and vulnerable, inhabit benthic macroinvertebrates that serve as important bioindicators of ecosystem health. The aim of the study was to assess the metal pollution in mining-impacted littoral sediments, the spatial gradient of the pollution and how the analyzed metals affect benthic macroinvertebrate communities. Three impacted and three reference lakes were examined for metal concentrations of Fe, Ni, Cu, Zn, Pb, Mn, and As, organic matter content, pH, and benthic macroinvertebrate community (family-level). Impacted lakes had significantly higher concentrations of Fe, Ni, Cu, Zn, and Pb, however Mn and As showed no significant differences. All metals showed exponentially higher levels, close to the impacted inlet, indicating a highly localized pollution issue. Higher metal concentrations were linked to increased organism abundance but lower community evenness, with tolerant taxa such as Chironomidae dominating, and metal-sensitive taxa, like Ephemeroptera, being less abundant; highlighting that taxa richness alone fails to capture community changes, similar to the ASPT (Average Score Per Taxon) score. Overall, this study concludes that mining legacies cause localized increases in littoral sediment metal pollution and drive shifts in benthic macroinvertebrate communities in littoral zones. Future research should ensure regular spatial gradients in the sampling sites, integrate bioavailable metal levels, and identify feeding groups for more comprehensive results.