Mine Waste Technology Program. Phosphate Stabilization of Heavy Metals Contaminated Mine Waste Yard Soils, Joplin, Missouri NPL Site

摘要

This document summarizes the results of Mine Waste Technology Project 22Phosphate Stabilization of Heavy Metals-Contaminated Mine Waste Yard Soils. Mining, milling, and smelting of ores near Joplin, Missouri, have resulted in heavy metal contamination of the area. The Joplin site was listed on the Superfund National Priorities List in August 1990. High blood levels in young children in the area have prompted efforts to reduce soil-based lead (Pb) (and cadmium) health threats. Previous investigations indicate that Pb bioavailability can be reduced via addition of 1% by weight phosphoric acid (PA) plus 0.05% potassium chloride. The purpose of this study was to determine if the treatment would be effective in mine waste-affected soils. Bioavailability of Pb is determined by measuring Pb levels in various tissues from young pigs following ingestion of a known quantity of Pb in treated and untreated soil or lead acetate. The data collected for the in vivo study were not sufficient to conclude (at the 95% confidence level) that PA-treatment had any particular effect on Pb bioavailability. The results of a parallel in vitro study were more encouraging. The extractable Pb was consistently lower in PA-treated soils compared to untreated soils.