2003 Comparison of the Soil Ecotoxicity of the Light and Heavy Ends of Fraction 3

Stantec Consulting Ltd.

About 60 per cent of Canada’s contaminated sites involve petroleum hydrocarbon (PHC) contamination that, left unaddressed, impairs the quality and uses of land and water. In 2001, the Canadian Council of Ministers of the Environment (CCME) established new, nationwide standards for total petroleum hydrocarbons in different types of soil. These are risk-based standards that determine the levels to which sites contaminated by PHC must be cleaned up. Since those standards were established, further research has gone into the relative toxicity of the various distillates, or “ fractions” , of crude oil mixtures. The lighter fractions (F1 and F2), while the most toxic, degrade relatively quickly in soil, compared with the less toxic but more persistent heavier fractions (F3 and F4). In particular, Fraction 3 was found [DG2]to be more toxic than expected in the laboratory. It was also found to be more difficult, in many cases, to remediate contaminated sites to the CCME standard for Fraction 3. At the same time, there has been an apparent lack of F3 toxicity observed at field sites exceeding the standard. This might [DG3]be attributed to the wide boiling point range of F3. At the lower range are compounds thought to be more toxic but more readily remediated. The higher boiling-point constituents that remain following remediation are, in turn, thought to be less toxic. If this is the case, it might be advisable to regulate and manage sites based on a division of Fraction 3 into lower molecular weight and higher molecular weight constituents. This project is thus studying whether this should be done.

2003 ERAC_Soil EcoToxicity of PHC F3 Fraction
Stantec_Soil Test Methods for Assessing Toxicity in Contaminated Soil Presentation
Stantec_Soil Ecotoxicity of Fraction 3 Presentation