Accelerated remediation of pesticide-contaminated soil with zerovalent iron

摘要

High pesticide concentrations in soil from spills or discharges can result in point-source contamination of ground and surface waters. Cost-effective technologies are needed for on-site treatment that meet clean-up goals and restore soil function. Remediation is particularly challenging when a mixture of pesticides is present. Zerovalent iron (Fe-0) has been shown to promote reductive dechlorination and nitro group reduction of a wide range of contaminants in soil and water. We employed Fe-0 for on-site treatment of soil containing > 1000 mg metolachlor, > 55 mg alachlor, > 64 mg atrazine, > 35 mg pendimethalin, and > 10 mg chlorpyrifos kg(-1). While concentrations were highly variable within the windrowed soil, treatment with 5% (w/w) Fe-0 resulted in > 60% destruction of the five pesticides within 90 d and increased to > 90% when 2% (w/w) Al-2(SO4)(3) was adjed to the Fe-0. GC/MS analysis confirmed dechlorination of metolachlor and alachlor during treatment. Our observations support the use of Fe-0 for ex situ treatment of pesticide-contaminated soil. (C) 2004 Elsevier Ltd. All rights reserved.