Zero valent iron reduces toxicity and concentrations of organophosphate pesticides in contaminated groundwater

► Zero valent iron (ZVI) was used for treatment of a complex contaminant mixture. ► Fast degradation of methyl parathion, ethyl parathion and malathion by ZVI. ► Degradation and sorption of phosphorous triesters and chlorinated aromatics. ► Great overall toxicity reduction (two orders of magnitude) for the complex mixture. ► Bioassays work well as a tool for accessing overall remedial success.