More scientific research needs to be done to understand and assess the environmental impacts of wastes from mining operations which have been disposed into the marine environment, a new report shows.
A number of large-scale mines worldwide use marine or riverine disposal for mine tailings, under Government permits.
The Joint Group of Experts on the Scientific Aspects of Marine Environmental Protection (GESAMP) report, Impacts of mine tailings in the marine environment, provides the findings of an international workshop held in Lima, Peru, in 2015 and makes a number of recommendations for future work. The report notes that there are major gaps that need to be addressed in the scientific understanding of the behaviour of mine tailings in the sea and the short- and long-term impacts on the marine environment and other potential users of marine resources.
Areas requiring more information:
1. Understanding behaviour of sediment plumes; physical and chemical behaviour of pollutants through the marine ecosystem.
2. Modelling of plumes (horizontal shearing and upwelling) and the resulting tailings footprint.
3. Enhanced toxicity testing to assess impacts to deep-sea ecosystems.
4. Understanding the ecological significance of smothering all benthic organisms in the disposal site footprint and physically altering the bottom habitat.
5. Identification of the reduction in species composition/abundance and biodiversity of marine communities.
6. Determining and understanding the significance of bioaccumulation of metals through food webs and ultimately into human fish-consuming communities; and potential increases in risk to human health.
7. Assessing recolonization potential of deep-sea benthos and limiting factors by deep-sea benthos; timescale for recovery of impacted areas.
8. Specialized sampling equipment for the deep-sea.
Since the workshop, GESAMP has established a dedicated working group to assess the environmental impacts of wastes from mining operations which have been disposed into the marine environment, under the co-lead of IMO and U.N. Environment.
The report is available here.