Mobility of aqueous contaminants at abandoned mining sites: insights from case studies in Sardinia with implications for remediation

Abstract

Public awareness of environmental health\ud issues has increased significantly in recent years, creating the need for detailed scientific studies that can identify potential environmental problems. This paper reports the results of hydrogeochemical surveys carried out in Sardinia,\ud an Italian region with a long mining history. When mining\ud operations in Sardinia ceased, actions for limiting the potential adverse effects of mine closure on the water\ud system were not undertaken. Drainages from flooded mines\ud and seeps from mining residues left on the ground are the main mining-related sources of contamination in Sardinia.\ud Due to the proximity of mining sites to water resources and land that is within reach of animals and humans, the major risks to human health are associated with the direct discharge\ud of contaminated waters into the streams and soils\ud located down-gradient of the abandoned mines. Results of\ud hydrogeochemical surveys carried out under different\ud seasonal conditions showed that the dispersion of toxic and harmful elements (As, Cd, Ni, Pb, Sb and Zn) increases\ud during the rainy season, especially under high runoff conditions.\ud These results should help regional and national\ud authorities to address present environmental regulations, particularly those regarding the quality of water resources.\ud Furthermore, the results might be useful elsewhere for\ud planning remediation actions at abandoned mining sites.\ud Lessons learned by past mining in Sardinia indicate that correct disposal and management of mining residues\ud should be mandatory from the beginning of exploitation\ud and processing at each active mine. This would allow\ud reduction of the environmental risks as well as the cost of remediation

Metals and metalloids in hair samples of children living near the abandoned mine sites of Sulcis-Inglesiente (Sardinia, Italy)

“…The impact of metal mining in Sardinia was described by Cidu and Fanfani (2002). More recently, deterioration of waters quality in the Sulcis-Iglesiente area, caused by mine drainage and the weathering of mining-related wastes, has been documented in several reports by Cidu et al (2007Cidu et al ( , 2009, Cidu (2011) and Medas et al (2012aMedas et al ( , 2012b, which found high concentrations of Zn, Cd and Pb in local surface and groundwaters. Stream sediments showed significant Zn-Mn-Pb-Cu-Ag anomalies as well as a wide diffusion of pollutant elements like Cd, As, Hg and Sb not directly exploited from the ores De Vivo et al, 1997;1998;.…”

Groundwater Mixing Process Identification in Deep Mines Based on Hydrogeochemical Property Analysis

“…There are four kinds of aquifer systems in the study area, including Cenozoic unconsolidated porous aquifers with the average thickness of [11][12][13][14][15][16][17][18][19][20][21][22] …”

“…Hydrogeochemical methodologies have been widely used to solve hydrogeological problems in mining [11][12][13][14], such as assessing the environmental effects of acid mine drainage (AMD) [2,[15][16][17][18][19][20], tracing the pollution sources in mining areas [21][22][23], and studying the leachate of mine tailings [24][25][26][27]. In order to investigate the evolution of the compositions in mining groundwater and the groundwater quality under the influence of ADM, the PHREEQC hydrogeochemical model and the expanded Durov diagram were performed in [28].…”

Influence of freeze–thaw dynamics on internal geochemical evolution of low sulfide waste rock

“…Environmental exposure of waste rock with a net acid generation potential can result in drainage water with a declining pH and elevated concentrations of sulfate and various metals (Blowes et al, 2003). Active and legacy mine sites can pose significant environmental and biological health concerns, with the affected area potentially reaching far beyond the borders of the original site (Cidu, 2011). In many cases the production of ARD can be detrimental to the environment and has the potential to last thousands of years (Blowes and Jambor, 1990;Nordstrom and Alpers, 1999).…”