Catchment-scale evaluation of potential particulate contaminant dispersion from post-mining sites under the effects of water erosion

The ever-growing demand for critical resources, including metals and metalloids elements, has resulted in a dramatic increase of tailings worldwide. Tailings may contain significant concentration of potentially harmful elements like lead or arsenic. During rainfall events, runoff and associated erosion may result in contaminant dispersion to river systems, which may be particularly deleterious for ecosystems and significantly affect human health. While the massive impact of tailing dam failures has been studied in the literature, much less attention has been paid to estimating the diffuse dispersion from tailings under the effects of rainfall and runoff. Recent works however suggested that it may be a significant risk for populations, considering the significant number of tailings scattered all over the World (Macklin et al., 2023).

In the current study, more than 2000 tailings were inventoried over France. This study proposes to build a methodology to assess both the catchments structural and functional connectivity linking tailings to river channels, in a selected set of catchments located in contrasted environments (i.e. catchments located in lowland, upland and mountainous areas), in France. The proposed methodology makes use of national-scale databases, including rainfall, discharge, and suspended sediment concentration time series as well as catchments characteristics (e.g. morphology and land use). The aim of this study is to encourage discussions on the topic of catchment-scale assessment of contaminant dispersion from mining wastes under the effects of rainfall and runoff. It should ultimately help decision-makers to prioritize tailings for management plan design.

 

Macklin M.G., Thomas C.J., Mudbhatkal A., Brewer P.A., Hudson-Edwards K.A., Lewin J., Scussolini P., Eilander D., Lechner A., Owen J., Bird G., Kemp D., Mangalaa K.R. (2023). Impacts of metal mining on river systems: a global assessment. Science, 381:1345-1350.