Contribution of fluorite mining waste to mercury contamination in coastal systems

Samples from 13 beaches along the northern Spanish coast, a region with a history of heavy industries, were first screened to identify signs of pollution. High concentrations of Hg and Ba on Vega beach were found, both elements belong to the fluorite ore paragenesis, mined in the surroundings. Samples of beach and fluvial sediments, and nearby soils were collected in Vega beach area to address potential Hg pollution, fate and sources. Most samples showed a similar pollutants fingerprint to that of beach samples, especially those taken from white dunes, registering notable Hg concentrations. Hg was enriched in the finer fractions, and overall the main input was attributed to the mining waste discharged along the coast in the past. Although a specific risk assessment and study of the submerged sediments are advisable for this area, Hg bioavailability and methylation were low, thus indicating that this metal poses a reduced environmental risk.