How Clean Is Clean? A Use of Hazard Assessment in Groundwater for Evaluation of an Appropriate Formaldehyde Spill Remedial Action Endpoint

A spill of formaldehyde from a pipe was discovered in October 1983 at a manufacturing site. Groundwater investigation revealed that much of the formaldehyde was trapped within a clay till layer 8 ft below the surface at a concentration of up to 9% by weight. The formaldehyde was leaching out of the unsaturated zone and moving into the saturated zone. A remedial action plan was begun that involved the oxidation of formaldehyde with injection of hydrogen peroxide coupled with pumping withdrawal and reuse of surrounding contaminated groundwater.