Mercury levels in Ghana exceed US levels by more than 55 times
By the AFREEQUE newsroom, based on Ghanaian Chronicle
The waters of Ghana’s Pra and Ankobra rivers have mercury concentrations more than 55 times the average measured in US waterways. Sediments also show levels up to 25 times higher, according to a USGS study presented in Accra.
Mercury concentrations measured in the waters of Ghana’s Pra and Ankobra rivers are more than 55 times the average recorded in US waterways. A baseline study by the United States Geological Survey (USGS), presented in Accra by researcher Grace Armstrong, links the highest concentrations to the proximity of artisanal and small-scale gold mining sites, the Ghanaian Chronicle reports.
Sediments in the two rivers have mercury concentrations between two and 25 times the US average. Bamianko is among the communities showing the highest levels in sediments because of its proximity to mining activities, according to Grace Armstrong of the USGS research laboratory dedicated to mercury, metals and microplastics.
The study indicates that the mercury detected in the water was largely associated with suspended particles. Filtered water samples had concentrations more than ten times lower than unfiltered samples, implying possible transport of the contaminant downstream and into the marine environment. Mercury can also be transformed into methylmercury, a highly toxic substance that can accumulate in aquatic food chains, particularly in fish, Grace Armstrong explained.
Drinking water samples taken from networks, boreholes and wells nevertheless remained below the thresholds set by the US Environmental Protection Agency, at 2 parts per billion, and by the World Health Organization, at 1 part per billion, according to the study.
