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RISK ASSESSMENT AND REMEDIATION OF SOILS CONTAMINATED BY MINING AND SMELTING OF LEAD, ZINC AND CADMIUM
Citation:
Chaney, R. L., S. L. Brown, T. I. Stuczynski, W. L. Daniels, C. L. Henry, Y. Li, G. Siebielec, M. Malik, J. S. Angle, J A. Ryan*, AND H. Compton. RISK ASSESSMENT AND REMEDIATION OF SOILS CONTAMINATED BY MINING AND SMELTING OF LEAD, ZINC AND CADMIUM. Ruiz, M.G. (ed.), INTERNATIONAL JOURNAL OF ENVIRONMENTAL POLLUTION. Universidad Nacional Autonoma de Mexico, 16(4):175-192, (2000).
Description:
Mining nd smelting of Pb, Zn and Cd ores have caused widespread soil contamination in many countries. In locations with severe soil contamination, and strongly acidic soil or mine waste, ecosystems are devastated. Research has shown that An phytotoxicity, Pb-induced phosphate deficiency, Cd risk through uptake by rice or tobacco, and Pb risk to children, livestock or wildlife which ingest soil are the common adverse environmental effects at such contaminated sites. Improved understandings of soil metal risks to the environment have been developed which examine risk to all possible exposed organisms through soil, plants, animals, or water exposures. This review summarizes present information about soil Cd risk to food-chains, explaining that when Cd is present at the usual 0.005-to-0.02 ratio to Zn in the contaminated soil, only rice and tobacco allow Cd to be transferred from the soil in amounts which can harm humans over their lifetime. Zn inhibits plant uptake of Cd, and inhibits intestinal adsorption of Cd, protecting animals from Cd in most situations. Pb risk to children or other highly exposed organisms results from ingestion of the contaminated soil, and absorption of Pb from the soil into the blood where adverse health effects occur at 10-15 ug Pb/dL blood. Soil Pb has much lower bioavailability than water Pb, and if ingested with food has even lower bioavailability. Research hs shown that if high phosphate levels are added to Pb contaminated soils, an extremely insoluble Pb compound is formed in soils from all known chemical species of Pb which occur in contaminated soils.