Romero F M, Villalobos M, Aguirre R, Gutiérrez M E
Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacan, 04510, Mexico D.F., Mexico.
Arch Environ Contam Toxicol. 2008 Nov;55(4):566-75. doi: 10.1007/s00244-008-9152-3. Epub 2008 Mar 5.
The goal of this work was to identify the solid-phase control on lead (Pb) bioaccessibility in soils impacted by smelter activities in the city of San Luis Potosi, in north-central Mexico. Total Pb concentrations in 30 ha of soil terrain from a residential area adjacent to the smelter showed levels above the 400-mg/kg intervention guideline dictated by Mexican Environmental regulations. These concentrations, although raising human health and environmental concerns, showed low water-soluble lead (<0.1 mg/L) and relatively low lead bioaccessibility (2.4-20.5%). X-ray diffraction and electron microscopy techniques showed, in addition to common Pb phases reported in similar contaminated environments [galena (PbS) and anglesite (PbSO(4))], the presence of a solid lead arsenate phase. The Pb solubility measured in soils agrees very well with the low solubility reported for the Pb minerals identified and explains the relatively low Pb bioaccessibility values measured, presumably from their low dissolution during passage through the gastrointestinal tract. The results reported are highly relevant for smelter-originated environmental contamination scenarios in general.
这项工作的目标是确定墨西哥中北部圣路易斯波托西市受冶炼活动影响的土壤中铅（Pb）生物可利用性的固相控制因素。来自冶炼厂附近一个居民区30公顷土壤区域的总铅浓度高于墨西哥环境法规规定的400毫克/千克干预指导值。这些浓度虽然引发了对人类健康和环境的担忧，但水溶性铅含量较低（<0.1毫克/升），且铅生物可利用性相对较低（2.4 - 20.5%）。X射线衍射和电子显微镜技术表明，除了在类似污染环境中报道的常见铅相[方铅矿（PbS）和白铅矿（PbSO₄）]外，还存在一种固态砷酸铅相。在土壤中测得的铅溶解度与所鉴定的铅矿物报道的低溶解度非常吻合，并解释了所测得的相对较低的铅生物可利用性值，这可能是由于它们在通过胃肠道过程中溶解度较低。所报道的结果总体上与冶炼厂产生的环境污染情况高度相关。
