The U.S. Environmental Protection Agency (EPA) Extraction Procedure (EP) is designed to simulate the leaching action of rain and groundwater in the acidic environment present in mixed landfills or open dumps. The objective of the present project is to compare concentrations of selected constituents obtained in the extraction testing with the concentrations of the same materials in leachate obtained from a large-scale industrial/municipal waste co-disposal test, that simulates conditions in an actual landfill.

The EPA Extraction Procedure was run on specimens of three industrial wastes: a sludge from an electroplating operation, a chlorine production sludge, and a glass etching (calcium fluoride) sludge. These same sludges were also tested by adding approximately one metric ton (dry weight) of industrial wastes to two metric tons (dry weight) of municipal wastes and leaching the combined wastes. Both extractant and leachate were analyzed for arsenic, cadmium, total chromium, copper, mercury, nickel, lead, selenium, and zinc. There was a remarkable lack of correspondence between the concentrations appearing in the extractants and in the leachates. In most cases, the concentrations observed in the leachates were higher than the concentrations observed in the extractant. However, for some metals where redox and the availability of sulfide ion strongly affect oxidation states and solubility, the concentrations in the aerobic extractant were much higher than in the anaerobic leachate.

If the goal of extraction testing is to simulate the effects of a landfill environment on a hazardous waste, additional test development may be required. Present test procedures did not always accurately predict the loss of constituents measured in this study.