[en] Contaminants at DOE sites encompass a range of common industrial pollutants. However, the prevalence of contaminant mixtures including organics, metals, and radionuclides is relatively unique to DOE's facilities. Bioremediation has been shown to be effective for destruction of many of the organic pollutants. The technology also has promise for application to many of the metals and radionuclides; however, field demonstrations for these applications have not yet been attempted. Because of the complexity of biodegradation of even a single-compound class, little has been done to develop or demonstrate in situ bioremediation technologies for multicompound combinations. The current bioremediation demonstration on CCl₄ and nitrates within the VOC-Arid Integrated Demonstration is one the first efforts to address inorganic and organic co-contaminants simultaneously. Additional research, technology development, and field demonstrations are needed to evaluate the applicability of in situ bioremediation to DOE's most common contaminant mixtures