ABSTRACT: Mercury is of particular concern amongst global environmental pollutants, with abundant contaminated sites worldwide, many of which are associated with mining activities. Asturias (Northwest of Spain) can be considered an Hg metallogenic province with abundant epithermal-type deposits, whose paragenetic sequences include also As-rich minerals. These mines were abandoned long before the introduction of any environmental regulations to control metal release from these sources. Consequently, the environment is globally affected, as high metal concentrations have been found in soils, waters, sediments, plants, and air. In this paper, a characterization of the environmental affection caused by Hg mining in nine Asturian mine sites is presented, with particular emphasis in Hg and As contents. Hg concentrations found in the studied milieu are similar and even higher than those reported in previous studies for other mercury mining districts (mainly Almadén and Idrija). Furthermore, the potential adverse health effects of exposure to these elements in the considered sites in this district have been assessed.
Environmental Science and Pollution Research 04/2013; · 2.65 Impact Factor
ABSTRACT: Hydrogeologically, the Central Coal Basin (Asturias, Spain) is characterized by predominantly low-permeability materials that make up a multilayer aquifer with very low porosity and permeability values, where the sandstones act as limited aquifers, and wackes, mudstones, shales and coal seams act as confining levels. Preferential groundwater flow paths are open fractures and zones of decompression associated with them, so the hydraulic behaviour of the system is more associated with fracturing than lithology. Thus, abandoned and flooded mines in the area acquire an important role in the management of water resources, setting up an artificial "pseudo-karst" aquifer. This paper evaluates the potential application of the abandoned mines as underground reservoirs, both for water supply and energetic use, mainly through heat pumps and small hydropower plants. In particular, the groundwater reservoir shaped by the connected shafts Barredo and Figaredo has been chosen, and a detailed and multifaceted study has been undertaken in the area. The exposed applications fit with an integrated management of water resources and contribute to improve economic and social conditions of a traditional mining area in gradual decline due to the cessation of such activity.
Journal of Environmental Monitoring 07/2012; 14(8):2127-36. · 1.99 Impact Factor
ABSTRACT: Experimental studies on the retention of metals (Cu, Co, Ni, and Zn) in bentonite samples from the Grau Region (Northern Peru)
have been accomplished using monometallic, bimetallic, trimetallic, and tetrametallic solutions. Parameters such as pH and
concentration of dissolved metals and organic compounds have been evaluated by means of batch adsorption experiments. Adsorption
rates indicate the suitability of these bentonites in the environmental industry for heavy metals retention purposes. In addition
to its quality as physical barrier to avoid the dispersion through the environment of polluted leachates, bentonite, due to
its high cation exchange capacity, can act also as a chemical barrier, protecting the quality of surface and groundwater systems,
while limiting the migration of heavy metals in solid residues or sludge stocked in security landfills. Adsorption rates of
tested bentonites were proved to decrease when concentrations of both metal and organic compounds, as well as the number of
ionic species, increase in solution; additionally, lower metal removal rates from solution were obtained when extremely acidic
conditions were achieved.
Environmental Geology 04/2012; 53(6):1323-1330. · 1.13 Impact Factor
ABSTRACT: A water reservoir constructed for production of hydraulic energy and drinking water in the Riaño valley (León, northern Spain) receives leachates from polluted soils and spoil heaps from a site where small-scale As mining and smelting operations have been developed in the first half of the twentieth century. Water of the upper catchments of the Esla, Yuso and Orza Rivers is stored in this reservoir. The location of these abandoned mine works within the reservoir drainage basin suggested that the stored water could contain high As concentrations. In order to evaluate possible environmental risks, a preliminary soil and surface water geochemical survey has been carried out downstream of the Santa Águeda Mine. Total As concentrations in soils reach 23,800mgkg−1 in soils and increase with depth, at least up to a depth of 80cm. Total As concentrations in surface waters reach 890 μgl−1. Despite the fact that there is an important As input to the water reservoir, the water flow from the mine catchment is a negligible contribution when compared with the total volume of water inside the dam (0.07%). This fact considerably decreases the environmental risk associated with the presence of untreated spoil heaps containing As-rich minerals at Santa Águeda mine site.
Environmental Geology 04/2012; 50(6):873-884. · 1.13 Impact Factor
ABSTRACT: Analytical results of soil samples taken in three different mercury mining sites in Northern Spain are studied to assess the potential adverse health effects of the exposure to trace elements associated with the mining process. Doses contacted through ingestion and inhalation and the dose absorbed through the skin were calculated using USEPA's exposure parameters and the US Department of Energy's toxicity values. The results of the risk assessment indicate that the highest risk is associated with ingestion of soil particles and that the trace element of major concern is arsenic, the exposure to which results in a high cancer risk value for all the sites ranging from 3.3 × 10(-5) to 3.6 × 10(-3), well above the 1 × 10(-5) probability level deemed unacceptable by most regulatory agencies. Regarding non-cancer effects, exposure to polluted soils yields an aggregate hazard index above the threshold value of 1 for all three sites, with As and Hg as the main contributors. Risk assessment has proven to be a very useful tool to identify the contaminants and exposure pathways of most concern in the soils from metal mining sites, as well as to categorize them in terms of action priority to ensure fitness for use.
Journal of Environmental Monitoring 10/2010; 13(1):128-36. · 1.99 Impact Factor
ABSTRACT: The mobility, bioavailability and toxicity of mercury in the environment
depend on the chemical species in which is present in soil, sediments,
water or air. In this work we used synchrotron radiation to determine
mercury species in geological samples of three mercury mining districts:
Almadén (Spain), Idria (Slovenia) and Asturias (Spain). The aim
of this study was to find differences on mobility and bioavailability of
mercury on three mining districts with different type of mineralization.
For this porpoises we selected samples of ore, calcines, soils and
stream sediments from the three sites, completely characterized by the
Almadén School of Mines, Josef Stefan Institute of Ljubljana and
Oviedo School of Mines. Speciation of mercury was carried out on
Synchrotron Laboratories of Hamburg (HASYLAB) by XANES techniques.
Spectra of pure compounds [HgCl2, HgSO4, HgO, CH3HgCl, Hg2Cl2 (calomel),
HgSred (cinnabar), HgSblack (metacinnabar),
Hg2NCl0.5(SO4)0.3(MoO4)0.1(CO3)0.1(H2O) (mosesite), Hg3S2Cl2
(corderoite), Hg3(SO4)O2 (schuetteite) y Hg2ClO (terlinguaite)] were
obtained on transmittance mode. The number and type of the compounds
required to reconstruct experimental spectra for each sample was
obtained by PCA analysis and linear fitting of minimum quadratics of the
pure compounds spectra. This offers a semiquantitative approach to the
mineralogical constitution of each analyzed sample. The results put
forward differences on the efficiency of roasting furnaces from the
three studied sites, evidenced by the presence of metacinnabar on the
less efficient (Almadén and Asturias) and absence on the most
efficient (Idria). For the three studied sites, sulfide species
(cinnabar and metacinnabar) were largely more abundant than soluble
species (chlorides and sulfates). On the other hand, recent results
on the mobility of both Hg and As on the target sites will be presented.
These results correlate with the related chemical species found by XANES
ABSTRACT: The abandoned mercury mining works of "Los Rueldos" are located 20 km from Oviedo, along the northwestern border of the Asturian Central Coal Basin, in an area with intense tectonization. Hg mainly appears as cinnabar, but occasionally metacinnabar and native Hg are present; associated with Hg ore appear As-rich minerals (arsenopyrite, As-rich pyrite, realgar and scorodite). In the spoil heap, Hg content ranges from 14 to 2224 mg kg(-1), and As from 4746 to 62,196 mg kg(-1). Mine drainage and spoil heap leachates show acidic conditions (pH: 2.43-2.50), 2900-4600 mg l(-1) sulphate, 1.4-9.2 mg l(-1) As, 0.03-0.48 mg l(-1) Pb, and 3.6-14 microg l(-1) Hg. According to the analytical data and characteristics of the site, the application of corrective measurements to avoid the dispersion of contaminants in the environment must be considered.
Science of The Total Environment 04/2005; 340(1-3):247-60. · 3.29 Impact Factor
J. Synchrotron Rad. 17(2010)2,179-186.