A summary of potential impacts of tailings dam failures on biodiversity and associated ecosystem services.
The impacts of tailings dam failures on biodiversity can be both immediate and long term (Figure 17). When large volumes of tailings enter waterways, the material can have physical (e.g. increased turbidity, smothering) and chemical (e.g. toxicity from toxic contaminates, decreased oxygen) impacts on aquatic organisms. The type and location of failure is, however, an important factor in the severity and extent of these impacts. Analysis of 306 reported tailings dam failures (reported in WISE 2017) indicates that 24 have occurred within a legally protected area, and a further 158 occurred within 10 kilometres of a protected area.
The impacts of these tailings dam failures on biodiversity are immediate, in terms of smothering habitats and contaminating waterways. Aquatic life is heavily impacted due to the extreme change in water chemistry. The suspended solids that are introduced can get trapped in fish gills, with flow-on effects on semi-aquatic and terrestrial species.
The flow of tailings burying aquatic and riparian nursery habitats and the persistence of heavy-metal contamination have also been shown to negatively affect the regenerative capacity of aquatic and terrestrial ecosystems, leading to long-term changes in ecosystem structure and functions. This severely impacts the services these ecosystems provide to people, such as flood defence, erosion control and soil stability, water purification and regulation, nutrient cycling and carbon storage. (Fernandes et al. 2016; Kossof et al. 2014). While the direct human costs of tailings dam failures are quantified, the long-term social costs in terms of poor heath, and loss of income and livelihoods that result from a degraded environment, remain largely unknown.
From collection: Mine Tailings Storage: Safety Is No Accident