On behalf of counsel for Getty Petroleum Marketing, Inc. (GPMI), Anchor QEA evaluated the extent to which client-affiliated gasoline service stations represent a source of methyl tertiary-butyl ether (MTBE) observed in nearby groundwater production wells that supply drinking water to Suffolk and Rockland Counties, New York. This work was part of a larger products liability litigation, in which municipalities and water supply companies have brought suit upon several major oil companies for damages associated with MTBE contamination of drinking water supplies across the nation. Suffolk and Rockland Counties were the first two cases affecting GPMI that were spun off from the larger case before the U.S. District Court.

For each of the subject supply wells, Anchor QEA conducted a detailed MTBE source evaluation with respect to existing and past GPMI-affiliated service stations.  Our evaluation was based on an assessment of proximity of known and potential MTBE sources to the wells, groundwater flow directions, capture zone calculations, interpretation of numerical groundwater flow model results, documentation of past spill and remediation activities at GPMI-affiliated stations, the history of observed MTBE concentrations in the wells, and groundwater travel time calculations.

Anchor QEA’s analyses were customized to site-specific considerations for each case.  For example, in Suffolk County, Anchor QEA supported its analyses by drawing from several previous studies that characterized the glacial aquifers, including numerical modeling studies delineating supply well capture zones.  In contrast, the fractured bedrock aquifer within Rockland County is not well characterized at the scale of a single supply well, so Anchor QEA’s analysis required establishment of likely groundwater flow directions, and hence accounted for the uncertainty inherent to fractured media flow patterns.

Anchor QEA’s analyses provided GPMI with a rigorous, weight-of-evidence assessment of its MTBE source potential for the supply wells evaluated.  Anchor QEA’s analyses were documented in expert reports that were submitted to the court and ultimately factored into a favorable outcome for the client.

For more information on this project, please contact John Edwards at jedwards@anchorqea.com.