INTRINSIC DECHLORINATION OF 1,2-DICHLOROETHANE AT AN INDUSTRIAL SITE

Bioremediation strategies for an industrial site located in the Rotterdam Harbor Area, the Netherlands and contaminated with 1,2-dichloroethane (1,2-DCA), are under investigation. The contamination is present in a confined anaerobic aquifer. The objective of the research is to assess the potential of intrinsic (bio )degradation and enhanced biodegradation as effective risk reducing measures. Close to the contaminant source, 1,2-DCA is present at concentrations up to 500 mg per liter. From the possible intrinsic dechlorination products of 1,2-DCA (i.e. 2-chloroethanol, vinylchloride, chloroethane and ethene), vinylchloride (VC) is occuring at relatively high concentrations (up to 2 mg/liter). The type, rate and parameter dependency of the dechlorination processes occurring in this aquifer are currently being investigated by analyzing groundwater concentration profiles of the dechlorination products and by performing laboratory studies with material from the contaminated site. First results indicate that natural attenuation alone, is not sufficient to prevent the plume from further spreading. Therefore a field study at pilot-scale is underway to evaluate remediation strategies which are designed from screening studies at the laboratory scale.