Hydrogeochemistry of abandoned Pb sulphide mines: the mining district of La Carolina (southern Spain)

• Published in: Environmental earth sciences Vol. 61; no. 1; pp. 37 - 46
• Main Authors: Hidalgo, M. Carmen, Rey, Javier, Benavente, José, Martínez, Julián
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.07.2010; Springer; Springer Nature B.V
• Subjects: Biogeosciences; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Environmental Science and Engineering; Exact sciences and technology; Geochemistry; Geology; Groundwater; Hydrogeology; Hydrology; Hydrology. Hydrogeology; Hydrology/Water Resources; Metals; Mines; Original Article; Pollution, environment geology; Terrestrial Pollution; Water quality; Iberian Peninsula; Southern Europe; Andalusia Spain; Europe; Jaen Spain; Spain; Spain, Andalucia, Jaen; Dissolved metals; Abandoned sulphide mines; Hydrogeochemistry; La Carolina; floods; ground water; metals; sulfates; pollution; aquifers; discharge; abandoned mines; pH; dissolved materials; drinking water; sulfides; calcium; streams; oxidation; magnesium; mining; carbonates; lead; natural attenuation; acidity; drainage; seasonal variations
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-009-0318-8

The impact of past mining activities on the quality of groundwater and surface water has been investigated in the mining district of La Carolina (southern Spain, province of Jaén), a region characterised by the presence of mineralisations of Pb–Ag, Cu and Fe sulphides and Ba sulphates. The chemistry of waters from flooded galleries, shafts and drainage adits has been compared with that of surface waters in the same area. Generally, waters present neutral pH, since carbonates neutralise the acidity produced by the oxidation of Fe-bearing sulphide minerals in the mine impacted water. Despite of this natural attenuation process, in most of the cases, the mine groundwater is of low quality and shows high dissolved SO 4 (up to 3.7 g/l), Fe and Mn contents (tens to hundreds mg/l), exceeding the limit established by the guidelines of the World Health Organization for drinking water. Generally, the surface waters are of the sulphate calcium–magnesium to magnesium types, with moderate mineralisation. Post-rebound mine waters caused degradation of receiving watercourses in which the Fe contents are usually high, with values close to 3 g/l, and the mineralisation is greater as the channels run down in the mining zone. During dry seasons a considerable increase of salts and metals dissolved in stream waters was found, due to the decreasing contributions by run-off in this semiarid region, whereas the abandoned mine discharges remained practically constant.