Mine Site Rehabilitation with Biosolids for Sustainable Development

Abstract.

Abandoned mine sites in the U.S.A. have left a legacy of environmental contamination. The lead (Pb) and zinc (Zn) mines in the Tri-State Mining District of southeast Kansas, southwest Missouri, and northeast Oklahoma are such mines. Remediation of the mine waste materials is a pressing environmental problem because of health concerns caused by the heavy metals. No one has studied the effect of biosolids on rehabilitation of the mine waste materials in Galena, Kansas, part of the Tri-State Mining District. Therefore, we applied biosolids to mine waste materials from Galena, where mines were operational between 1871 and 1970, when they closed. Under greenhouse conditions, we grew sudex, a sorghum-sudangrass hybrid, in large pots of mine waste materials with and without biosolids. At termination of the experiment, four months after planting, the plants were harvested, and roots, shoots, and heads with grain were analyzed for heavy metals. The plants without biosolids produced minimal shoot dry matter (1.3 g pot^-1) and never produced grain. The plants with the biosolids produced 13 times more shoot dry matter (17.1 g pot^-1) and produced grain. The biosolids reduced uptake of the heavy metals. Even though large amounts of Pb and Zn accumulated in the roots, concentrations of Pb and Zn in the heads were within normal concentration ranges. The results showed that the use of biosolids appears to be a promising method to reduce bioavailability of heavy metals at contaminated mine sites, and, at the same time will allow revegetation for sustainable development.