Beak Douglas G, Basta Nicholas T, Scheckel Kirk G, Traina Samuel J
School of Environment and Natural Resources, Ohio State University, 2021 Coffey Rd, Columbus, Ohio 43210, USA.
Environ Sci Technol. 2008 Feb 1;42(3):779-85. doi: 10.1021/es071733n.
Lead (Pb) sorption onto oxide surfaces in soils may strongly influence the risk posed from incidental ingestion of lead-contaminated soils. In this study, Pb was sorbed to a model soil mineral, birnessite, and was placed in a simulated gastrointestinal tract (in vitro) to simulate the possible effects of ingestion of a soil contaminated with Pb. The changes in Pb speciation were determined using extended X-ray absorption fine structure and X-ray absorption near edge spectroscopy. Birnessite has a very high affinity for Pb with a sorption maximum of 0.59 mol Pb kg(-1) (approximately 12% Pb sorbed by mass) in which there was no detectable bioaccessible Pb (< 0.002%). Surface speciation of the birnessite Pb was determined to be a triple corner sharing complex in the birnessite interlayer. Lead sorbed to Mn oxide in contaminated media will have a very low (approximately equal to 0) Pb bioaccessibility and present little risk associated with incidental ingestion of soil. These results suggest that birnessite, and other Mn oxides would be powerful remediation tools for Pb-contaminated media because of their high affinity for Pb.
铅（Pb）在土壤中氧化物表面的吸附可能会强烈影响因偶然摄入铅污染土壤而带来的风险。在本研究中，将铅吸附到一种模拟土壤矿物水钠锰矿上，并置于模拟胃肠道（体外）中，以模拟摄入受铅污染土壤可能产生的影响。使用扩展X射线吸收精细结构和X射线吸收近边光谱法测定铅形态的变化。水钠锰矿对铅具有非常高的亲和力，最大吸附量为0.59摩尔铅/千克（约12%的铅按质量计被吸附），其中未检测到可生物利用的铅（<0.002%）。水钠锰矿中铅的表面形态被确定为水钠锰矿层间的三面共享络合物。在受污染介质中吸附到锰氧化物上的铅具有非常低（约等于0）的生物可利用性，并且因偶然摄入土壤而带来的风险很小。这些结果表明，由于水钠锰矿和其他锰氧化物对铅具有高亲和力，它们将成为修复铅污染介质的有力工具。
