RETRACTED: Assessing Mercury Contamination Levels in the Sediments of Two Pyrenean Lakes

Abstract

Mercury, a trace metal, is a persistent environmental pollutant that can be detected even in remote regions, including high-mountain lakes. This study examined mercury concentrations in the sediment of two lakes in the French Pyrenees, the Legunabens and Labant lakes. Sediment samples were collected using a Hon-Kajak Sediment Corer, and mercury concentrations were measured following the EPA 7473 method with a direct mercury analyzer (DMA-80). Mercury levels reached up to 283 ng g−1 in the Legunabens lake and up to 110 ng g−1 in the Labant lake, possibly linked to the mining history of the Ariège department and atmospheric deposition from distant sources. These findings indicate significant contamination, ranging from an 8% to 42% probability of generating adverse biological effects according to Canadian standards, and approximately 90% higher concentrations compared to average mercury concentrations in other Pyrenean lakes. Such contamination poses potential risks to aquatic life and the environment due to mercury’s toxicity and bioaccumulation in microorganisms.