Factors controlling the element distribution in farming soils and water around the abandoned Halikoy mercury mine (Beydag, Turkey)

Acid mine drainage, downstream transport of metal-rich water and sediment runoff adversely effect the environment surrounding the Hahkoy Hg mine. This study focuses on the environmental effects of the Hahkoy Hg mine on soil, stream sediment and water because the area is used for agricultural purposes. Stream sediment and farming soil have been polluted by contaminants derived from the mine. The effects of Hg mining and the distribution of contaminants in soil and stream sediment were evaluated by calculation of enrichment factors (EFs) which indicated enrichments for As, Hg, Sb and Pb. Other metals Cd, Co, Cr, Cu, Fe and Zn show moderate enrichment in soil close to the mine. EFs indicate soil contamination in the order of: Hg > As > Sb > Ni > Co > Cu > Fe > Zn > Cr > Pb > Cd. The greatest contamination was found near mine wastes, decreasing with increasing distance from the mine site. Concentrations of As, Cd, Cu, Ni, Pb and Zn are enriched in mine water. Acidic mine water samples have low pH (2.5-3.0) and high dissolved solids with electrical conductivity (EC) of about 3800 mu S/cm. Low pH in the groundwater (as low as 3.7) was also observed close to the stream draining of the mine. The source of acidity is the oxidation Fe-sulfides (dominantly pyrite) which release Fe, SO42- and H+ forming acid in mine water runoff. Concentrations of Hg are elevated (0.04-1.2 mu g/L) in acidic mine water and groundwater exceeding the US Environmental Protection Agency (USEPA) aquatic life Hg standard of 12 ng/L by as much as 100 times. (C) 2009 Elsevier Ltd. All rights reserved.