The international team of researchers of the study, published in Science, set to understand the total contamination of toxic waste from metal mines around the world. The results highlight the widespread reach of the contamination, with very concerning numbers. It affects approximately more than 470,000 kilometres of river channels and encompassing more than 160,000 square kilometres of floodplains, flat areas of land next to a river or stream, on a global scale. An estimated 23 million people reside on these affected floodplains, with more than 5 million head of livestock and over 65 thousands square kilometres of irrigated land.
Humans can become exposed to these contaminant metals in various ways, including direct exposure through skin contact, accidental ingestion, inhalation of contaminated dust, and through the consumption of contaminated water or food grown on contaminated soils.
Health in low-income countries and communities
This poses an additional hazard to the health of urban and rural communities in low-income countries and communities dependent on these rivers and floodplains, especially in regions already burdened with water-related diseases. In industrialised nations in Western Europe, including the UK, and the United States, this contamination constitutes a major and growing constraint to water and food security, compromises vital ecosystem services, and contributes to antimicrobial resistance in the environment.
New set of tools and datasets
The problem is well known, but so far, its magnitude was never quantified. The team of researchers used a new georeferenced global database of 185,000 metal mines compiled by the team. They employed a combination of process-based modelling and empirical testing. VU Amsterdam researchers Paolo Scussolini and Dirk Eilander had a specific role in the research. They used models to create unique global maps of river floods, mimicking pre-industrial conditions in climate and human influences. This provided the ideal basis for their colleagues, who in turn simulated the dispersion of the contamination that has taken place along centuries of mining activities.
Improve management of mining
These findings provide a sobering picture of the unintended, long-term consequences of our productive system. Metal mining is not going to disappear; on the contrary, it will grow to enable development and the energy transition. Therefore, knowing the extent and location of mining contamination is essential to prioritise areas for remediation and containment of pollution, and to improve management of mining.