Summary of public comments received on the draft screening assessment for base oils

Comments on the Draft Screening Assessment for Base Oils, assessed under the Chemicals Management Plan (CMP), were submitted by the Canadian Fuels Association and Imperial Oil.

Summarized public comments and responses are provided below, organized by topic:

Overarching comments

Summarized comment Summarized response
It is recommended that the Government of Canada define the term “distillates” in the screening assessment.The original text was reviewed and considered adequate as it clearly states that base oils are derived from vacuum distillation and have high boiling points (and thus low volatility), and does not refer to these substances as fuels. Similar use of the term “distillates” has been applied in past assessments of heavy distillates (e.g., heavy fuel oils) without any confusion for readers.
It was noted that details of use, emissions, and exposure from base oils in commerce have not been included in the publication; however, this would be beneficial to include.Information on the use of base oils has been included in the sources and uses section of the screening assessment (section 4.2), and emissions have been considered in the releases to the environment section (section 5). The exposure of Canadians to base oils from industrial uses has been addressed in the environmental media section of the screening assessment (section 8.1.1). Environment media exposures from unintentional releases during industrial uses and transportation of base oils are considered to be similar to those which have also been considered in the screening assessments of the Gas Oils [Site Restricted]; Heavy Fuel Oils [Site Restricted]; Gas Oils [Industry Restricted]; and Heavy Fuel Oils [Industry Restricted]. These routes were not expected to contribute to general population exposure to base oils.The ecological exposures from base oils in commerce have been considered in detail in the potential to cause ecological harm section of the screening assessment (section 7).
Editorial recommendations have been provided for consideration.The original texts were revised, where appropriate, based on the recommendations.
It is recommended that a clearer distinction be made in the screening assessment between polycyclic aromatic compounds (PACs) and polycyclic aromatic hydrocarbons (PAHs).Text to distinguish between PACs and PAHs has been added to the screening assessment.

Ecological assessment

Summarized comment Summarized response
Data in the table describing the acute and chronic toxicity of heavy base oils with varying aromatic content do not support the statement that wastewater treatment more effectively removes less toxic aliphatic components.Additional information was added to the screening assessment to clarify the statement.
The focus should be on the absolute toxic units (TUs) released and not on LL50s in the analysis in the sections on ecological effects assessment and risk analysis.The original text was reviewed and considered adequate. The discussion in the ecological effects section is specific to hazard characterization. The toxic unit metric incorporates both hazard and exposure and would go beyond scope of the analysis in this section. Hazard and exposure are considered in the risk analysis section following standard Environment and Climate Change Canada methods.
The modelling strategy and tool used for determining the predicted environmental concentrations for the release of base oils during the use in the treatment of wastewater should be cited for transparency and reliability checks.Additional information has been added to the screening assessment. A supporting document, which provides the detailed analysis, is cited in the assessment and is available upon request.
It would be useful to include the identity of the model used in the determination of the predicted environmental concentrations from the use of base oils in the pulp and paper industry.Additional information has been added to the screening assessment. A supporting document, which provides the detailed analysis, is cited in the assessment and is available upon request.
Please provide more information on the biodegradation study API 2011b that noted a cessation in biodegradation by day 28.This is a summary of an industry study that is not publically available; therefore, further detail on this study is not available.
Revisions should be made to several statements regarding the biomagnification and biota-sediment accumulation factors (BSAFs) of PAHs or alkyl-PAHs.Changes were made to the screening assessment based on suggested revisions, where appropriate.

Human health assessment

Summarized comment Summarized response
Additional clarification is required to explain how the methodology of the composition analysis is consistent with the IP 346 method.Additional clarification was added to the screening assessment.
The high production volume (HPV) category assessment document for lubricating oil base stocks indicates that none of the base oils were sensitizing.The health effects assessment section of the screening assessment was revised to clarify that base oils were not found to be sensitizing agents
It is recommended that the assessment note some of the uncertainties of the potency factor approach, as identified by the EPA Scientific Advisory Board’s report [Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (February 2010 Draft)].The use of the potency factor approach has been added to the uncertainties section of the human health assessment

Conclusions

Summarized comment Summarized response
Support for the screening assessment and the proposed conclusion was expressed. Noted.

References and sources

Summarized comment Summarized response

Consider revising the following statement in the draft screening assessment for clarity: “Solubility and volatility of a component decrease when the component is present in a mixture (Banerjee 1984; Potter and Simmons 1998)” As the Banerjee 1984 reference does not appear to be relevant, and the Potter and Simmons 1998 reference is not accessible.

Also, please revise the sentence on the order of biodegradation for hydrocarbons to be more specific.

Clarifications were made in the screening assessment.

Equation 7 in the Banerjee (1984) reference applies to hydrophobic substances in general, and therefore the citation is applicable. An additional reference (Di Toro et al. 2007) specific to petroleum has been added.

The Potter and Simmons (1998) reference is available for purchase through the U.S. Environmental Protection Agency Health and Environmental Research Online (HERO) website or through the Association for Environmental Health and Sciences Foundation.

The sentence on the order of biodegradation for hydrocarbons was revised.

An error in a citation was noted in the discussion on biodegradation of petroleum substances in the environment.The error was corrected and the citation changed from Pancirov and Brown (1975) to Atlas (1981).

In the health effects assessment section of the draft screening assessment, the reference Chasey 1993 does not specifically focus on un-refined oils. The following reference may be more appropriate:

McKee RH, Daughtrey WC, Freeman JJ, Federici TM, Phillips RD, Plutnick RT. 1989. The dermal carcinogenic potential of unrefined and hydrotreated oils. J Appl Toxicol 9: 265-270.

The additional reference was included in the screening assessment.
The reference for the citation Dalbey et al., 2004 is not included in the reference list. The citation was corrected in the screening assessment to Dalbey et al., 2014.

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