Soil Acidification, Mineral Neoformation and Heavy Metal Contamination Driven by Weathering of Sulphide Wastes in a Ramsar Wetland

Past waste disposal practices have left large volumes of sulphidic material stockpiled in a Ramsar wetland site on the Atlantic coast southwestern Spain, leading to severe land degradation. With aim addressing this legacy issue, soil core samples were collected along two transects extending from abandoned stockpiles adjacent marshland and subjected XRD, SEM-EDS, ICP-OES ICP-MS analyses. Sulphide oxidation has been shown be major driver acid generation metal leaching into environment. The marsh receiving discharges sulphide wastes contains elevated levels (in mg kg−1) Pb (up 9838), As 1538), Zn 1486), Cu 705), Sb 225) Tl 13), which are retained both relatively insoluble secondary minerals (mainly sulphates oxides) easily soluble hydrated salts that serve as transitory pool acidity available metals. By using number enrichment calculation methods relate concentrations their baseline regulatory thresholds, there is enough evidence conclude these pollutants may pose an unacceptable risk human ecological receptors.