Abstract: Compositions and methods are described to accomplish the in-situ remediation of contaminated groundwater and soil. Such compositions may comprise oil droplets, a water-miscible non-aqueous liquid phase, and one or more solid particulates. The oil droplets and the solid particulates are contained within the water-miscible non-aqueous liquid phase. The solid particulates may comprise one or more of zero valent iron, iron silicide, ferrosilicon, magnetite, particulate carbon, iron/carbon composites, calcium carbonate, and palladium. The solid particulates may comprise zero valent iron particles. The water-miscible non-aqueous liquid phase may be glycerol and the composition may be an oil-in-glycerol emulsion. Exemplary methods of preparing a groundwater remediation product comprise mixing oil droplets, a water-miscible non-aqueous liquid phase, and solid particulates contained in the water-miscible non-aqueous liquid phase to form a composition.