The development of chemical#x2010;specific, risk#x2010;based soil cleanup guidelines results in timely and cost#x2010;effective remediation

摘要

Millions of dollars of limited state cleanup funds are spent each year in New Hampshire to identify, sample, excavate, and treat thousands of tons of contaminated soil. Cost analyses of numerous sites indicated that soil remediation costs alone reach upwards of $300,000.00 per site. The New Hampshire Department of Environmental Services #x201C;Interim Policy for Management of Soils Contaminated from Spills/Releases of Virgin Petroleum Products#x201D;; (DES, 1989, 1991) set conservative remediation goals based on total petroleum hydrocarbons in 1989 using the Leaching Potential Analysis method (California Luft Manual, 1989). A current review of available literature and several case histories indicated that chemical#x2010;specific soil cleanup levels may be more appropriate for establishing remedial goals.Newchemical#x2010;specific soil cleanup guidelines using a risk#x2010;based approach have been developed. These new guidelines are conservatively based using two principal considerations: (1) an assumed soil exposure scenario that estimated the human health risks associated with potential long#x2010;term exposure to site soils via ingestion, inhalation and dermal contact and (2) the estimated fate and transport of chemicals of concern in the soil unsaturated zone. The first consideration assumed a total cancer risk that did not exceed 1 #xD7; 10#x2010;6. The second consideration employed the use of the SEasonal SOIL Compartment (SESOIL) model which simultaneously models water transport, sediment transport, and pollutant fate (US EPA, 1981). Several state soil standards from Oregon, Wisconsin, Massachusetts, and other states were extensively reviewed in order to develop a level of confidence that use of the SESOIL model was appropriate. A series of #x201C;sensitivity#x201D;; analyses was also performed in order to evaluate the response of the model to changes in various input parameters unique to New Hampshire's hydrogeologic conditions. Generic soil cleanup guidelines were developed for 24 petroleum#x2010;based volatile and semivolatile chemicals of concern to be applied statewide. Site#x2010;specific soil cleanup guidelines will be allowed if it can be demonstrated that insertion of site#x2010;specific data into the model will not adversely affect groundwater quality. As a result of the above processes, timely and much more cost#x2010;effective remediation will be achieved while still maintaining a high degree of protection of the groundwater quality and human health.