In vitro lead bioaccessibility and phosphate leaching as affected by surface application of phosphoric acid in lead-contaminated soil

• Published in: Archives of environmental contamination and toxicology 2002-11, Vol.43 (4), p.399-405
• Main Authors: YANG, J, MOSBY, D. E, CASTEEL, S. W, BLANCHAR, R. W
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Applied ecology; Applied sciences; Aves; Biological and medical sciences; Biological Availability; Contamination; Cost engineering; Decontamination. Miscellaneous; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on vertebrates; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Groundwater; Groundwater pollution; Humans; Leaching; Lead; Lead - pharmacokinetics; Lead - toxicity; Phosphorus - chemistry; Phosphorus - pharmacology; Pollution; Pollution abatement; Public Health; Smelters; Soil (material); Soil and sediments pollution; Soil contamination; Soil pH; Soil Pollutants - pharmacokinetics; Soil Pollutants - toxicity; Soil pollution; Soil profiles; Soil stabilization; Soil surfaces; Solubility; Superfund; Terrestrial environment, soil, air; Toxicology; Water Movements; Water Pollutants - pharmacokinetics; Water Pollutants - toxicity
• ISSN: 0090-4341; 1432-0703
• DOI: 10.1007/s00244-002-1197-0

Phosphate treatment of lead-contaminated soil may be a cost-effective remedial alternative for in situ stabilizing soil Pb and reducing Pb toxicology to human. The leaching behaviors of the P added to soil surface and the effect on subsurface Pb bioaccessibility must be addressed for this remedial technology to be acceptable. A smelter-contaminated soil containing an average of 2,670 mg Pb kg(-1), collected from the Jasper County Superfund Site located in Jasper County, Missouri, was surface treated with 10 g P kg(-1) as phosphoric acid (H(3)PO(4)). Following a simulated column leaching and 90-day treatment of field plots, respectively, bioaccessible Pb, P, and pH in soil profile were measured. Surface treatment using H(3)PO(4) effectively stabilized soil Pb and reduced leachable Pb and the bioaccessibility. Phosphate leached into deeper profile significantly lowered bioaccessible Pb in subsurface. Reduction of Pb bioaccessibility increased as a linear function of increasing soil P. Although surface H(3)PO(4) treatment resulted in an enhanced leaching of added P and may increase potential risk of surface and groundwater pollution, the P leaching under field conditions is very limited. Lime addition following the treatment may reduce the leachability of added P and further immobilize soil Pb.