Abstract |
This document describes groundwater pathway analyses performed to support the petroleum refining listing determination. The analyses were designed to determine the potential exposure, via the groundwater pathway, to human receptors from petroleum refining wastes, being managed and/or disposed in land management units. The exposure is expressed in terms of the contaminant concentration at a groundwater extraction well located down-gradient from the waste-management unit. Wastestreams and waste constituents of potential concern are identified by comparing the model predicted exposure concentrations to health-based numbers (HBNs) for both carcinogens and non-carcinogens. In the current modeling analyses, revisions have been made to several modeling assumptions such as landfill active lifetime and offsite landfill area distributions. The revisions were made based on EPA's reevaluation of the petroleum refining data in response to public comment on the NODA. |