Silva Veronica, Loredo Jorge, Fernández-Martínez Rodolfo, Larios Raquel, Ordóñez Almudena, Gómez Belén, Rucandio Isabel
ETS Ingenieros de Minas, Dpto. de Explotación y Prospección de Minas, Universidad de Oviedo, Independencia, 13, 33004, Oviedo, Spain.
Environ Geochem Health. 2014 Oct;36(5):831-43. doi: 10.1007/s10653-014-9602-y. Epub 2014 Apr 13.
Tailings from abandoned mercury mines represent an important pollution source by metals and metalloids. Mercury mining in Asturias (north-western Spain) has been carried out since Roman times until the 1970s. Specific and non-specific arsenic minerals are present in the paragenesis of the Hg ore deposit. As a result of intensive mining operations, waste materials contain high concentrations of As, which can be geochemically dispersed throughout surrounding areas. Arsenic accumulation, mobility and availability in soils and sediments are strongly affected by the association of As with solid phases and granular size composition. The objective of this study was to examine phase associations of As in the fine grain size subsamples of mine wastes (La Soterraña mine site) and stream sediments heavily affected by acid mine drainage (Los Rueldos mine site). An arsenic-selective sequential procedure, which categorizes As content into seven phase associations, was applied. In spite of a higher As accumulation in the finest particle-size subsamples, As fractionation did not seem to depend on grain size since similar distribution profiles were obtained for the studied granulometric fractions. The presence of As was relatively low in the most mobile forms in both sites. As was predominantly linked to short-range ordered Fe oxyhydroxides, coprecipitated with Fe and partially with Al oxyhydroxides and associated with structural material in mine waste samples. As incorporated into short-range ordered Fe oxyhydroxides was the predominant fraction at sediment samples, representing more than 80% of total As.
废弃汞矿的尾矿是金属和类金属的重要污染源。西班牙西北部阿斯图里亚斯的汞矿开采自罗马时代一直持续到20世纪70年代。汞矿床的共生矿物中存在特定和非特定的砷矿物。由于密集的采矿作业，废料中含有高浓度的砷，这些砷可通过地球化学作用扩散到周边地区。土壤和沉积物中砷的积累、迁移性和有效性受到砷与固相的结合以及颗粒大小组成的强烈影响。本研究的目的是研究矿山废料（拉索特拉尼亚矿场）细粒度子样本和受酸性矿山排水严重影响的河流沉积物（洛斯鲁埃尔多斯矿场）中砷的相态关联。采用了一种将砷含量分为七个相态关联的砷选择性连续提取程序。尽管在最细粒度的子样本中砷的积累量较高，但砷的分级似乎并不取决于粒度，因为在所研究的粒度级分中获得了相似的分布曲线。在两个地点，最易迁移形态的砷含量相对较低。在矿山废料样本中，砷主要与短程有序的铁羟基氧化物结合，与铁共沉淀，部分与铝羟基氧化物共沉淀，并与结构物质相关联。在沉积物样本中，结合到短程有序铁羟基氧化物中的砷是主要部分，占总砷的80%以上。
