2005 Summary of Chronic Screening Toxicity Test Results with Reference Soils and Soils Contaminated with Petroleum Hydrocarbon Residuals

There is an industry-wide concern that the Tier 1 Canada-Wide Standards for Fraction 3 in soils (CCME CWS PHC-F3) might be overly conservative for sites containing biotreated or naturally attenuated petroleum hydrocarbons (PHCs). The latter include invert drilling wastes, and crude oil originating from spills, flare pits and other cumulative releases that have undergone attenuation or remediation (i.e., aging and weathering) to a significant degree, but that have not met the existing guideline levels particularly for the CCME CWS PHC Fraction 3.

It is currently accepted that for most sites requiring remediation, conventional bioremediation technologies will reduce PHC concentrations for Fraction 1, 2 and 4 to below the CCME CW Tier 1 standards, with the exception of the PHC Fraction (F3). The F3 criteria were developed using fresh crude oil, and fail to recognize probable differences in ecotoxicity within the broad range of PHC products, as well as fundamental differences between fresh and weathered/aged PHCs. This limits industry from utilizing the less costly bioremediation technologies and dramatically increases remediation costs to excessive dollar values, and could result in the loss of a valuable resource (i.e., surface soils).

The upstream oil and gas industry believes that fully bioremediated soils, containing elevated residual F3 concentrations that exceed the soil-contact Tier 1 standards for the F3, can exist and still be protective of human health and the environment.