Development of criteria for response to oil and petroleum product spills on soils

Abstract

The major hydrocarbon constituents that often contaminate groundwater resources from oil and petroleum product spills are benzene, toluene, ethylbenzene, and xylenes (BTEX). Benzene is the most toxic and most mobile hydrocarbon constituent among these chemical. Benzene level in the contaminated soil from a spill can be used as a determining factor in selecting response actions for cleaning up the contaminated area regarding the protection of groundwater resources. This study developed cleanup criteria for oil and petroleum contaminated soils at spill sites. The maximum contaminant level (MCL) of benzene allowable in drinking water as established by USEPA was selected as a criterion to assess whether or not the groundwater will be contaminated as the result of the entering of benzene contained soil leachate at the spill site. If the anticipated maximum benzene concentration in soil leachate reaching the groundwater table is below the MCL, no action is needed to protect the groundwater and the natural degradation processes will take care of the spilled materials. If the anticipated maximum benzene concentration in soil leachate is close to the MCL when it reaches the groundwater level or there is no usable groundwater aquifers in the spill area, minor treatment actions can be taken to treat the contaminated soil on site; such as in situ bioremediation, in situ air-venting, surface covering, or addition of natural organic materials to the contaminated soil. If the anticipated maximum benzene concentration in soil leachate entering the groundwater will be much greater than the MCL and the groundwater resource is likely to be contaminated, major remedial actions will be needed. Should the remedial actions mentioned above be proven to be insufficient, contaminated soils will need to be removed from the spill site for off-site treatment at a commercialized treatment facility or disposal at a regulated hazardous waste disposal site. Computer simulation provides a practical and economical way to estimate the anticipated benzene concentrations in soil leachate resulting from a specific spill...