ARS | Publication request: Testing amendments for remediation of military range contaminated soil

Submitted to: Journal of Environmental Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 20, 2012
Publication Date: October 15, 2012
Citation: Siebielec, G., Chaney, R.L. 2012. Testing amendments for remediation of military range contaminated soil. Journal of Environmental Management. 108:8-13.

Interpretive Summary: Military firing ranges are commonly contaminated with heavy metals and occasionally become barren due to the phytotoxicity of Zn or Cu. An area of highly contaminated soil at the Aberdeen Proving Grounds, MD, where wastes from a munitions waste burn pit were pushed out onto adjoining land near the Chesapeake Bay. The site was nearly devoid of vegetative cover, and rich in Pb and Zn, so plant cover was needed to prevent erosion of the contaminated soil into surface waters. US-EPA and DOD asked for assistance in remediation of the soils. Because our previously demonstrated remediation method of incorporation of biosolids compost and limestone has been so effective at other locations, a greenhouse pot test was conducted with the highly contaminated soil. ‘Houndog’ tall fescue was grown on soil with 7 treatments including control, NPK fertilizer, limestone+NPK, high phosphate plus NPK, ‘Orgro’ biosolids compost, compost plus limestone and compost plus limestone plus Mn sulfate. The last treatment was included because in other research with a low Mn soil in which liming was required to remediate Ni phytotoxicity, the liming induced Mn deficiency; the DOD Coastal Plain soil was susceptible to Mn deficiency if limed, so the Mn fertilized treatment was included. Grass on the control, NPK, and phosphate+NPK treatments was chlorotic due to Zn phytotoxicity. Liming reduced Zn phytotoxicity and chlorosis, but only increased yield somewhat. All compost treatments cured the Zn phytotoxicity and produced healthy green foliage with high yield. Analysis of the plant shoots confirmed Zn phytotoxicity which was particularly well remediated by the compost plus limestone treatments. High soil Pb was also a concern, and biosolids compost was previously shown to strongly reduce the bioaccessibility of soil Pb. In this case, compost treatments strongly reduced soil Pb bioaccessibility compared to the control and non-compost treatments. The results of the experiment were the basis for a remediation action at the DOD site and effective vegetative cover was achieved in the field.

Technical Abstract: Military range soils are often strongly contaminated with metals. Information on effectiveness of remediation techniques on these soils is scarce. We tested effectiveness of compost and mineral treatments for remediation of military range soil collected in Aberdeen, MD. The soil was barren due to zinc (Zn) phytotoxicity while lead (Pb) posed a substantial risk for soil biota, wildlife and humans through various pathways. Seven treatments were tested: untreated control, agricultural NPK fertilization, high phosphate fertilization plus agricultural rates of NK, CaCO3 + NPK, “Orgro” biosolids compost (from Baltimore, MD), “Orgro” + CaCO3, “Orgro” + CaCO3 + Mn sulfate. All compost treatments alleviated Zn phytotoxicity symptoms and increased yield, while compost combined with liming reduced plant Zn concentration to non-phytotoxic 158-162 mg/kg. Compost plus limestone reduced Pb in-vitro bioaccessibility from 31.0 to 18.8% of total Pb being the most effective among the tested treatments. The study confirmed the high effectiveness of biosolids compost plus limestone in stabilization of metals in military range contaminated soils.