Waste/used crankcase oils priority substance list follow-up report: chapter 5

5. Assessment of "toxic" under CEPA (1999)

The environmental risk assessment of a Priority Substance List (PSL) substance is based on the procedures outlined in Environment Canada (1997). Analysis of exposure pathways and subsequent identification of sensitive receptors are used to select environmental assessment endpoints (e.g., adverse reproductive effects on sensitive fish species in a community). For each endpoint, a conservative Estimated Exposure Value (EEV) is selected and an Estimated No-Effects Value (ENEV) is determined by dividing a critical toxicity value (CTV) by an application factor. A hyperconservative or conservative quotient (EEV/ENEV) is calculated for each of the assessment endpoints in order to determine whether there is potential ecological harm in Canada. If these quotients are less than one, it can be concluded that the substance poses no significant risk to the environment, and the risk assessment is completed. If, however, the quotient is greater than one for a particular assessment endpoint, then, for most substances, the risk assessment for that endpoint proceeds to an analysis where more realistic assumptions are used and the probability and magnitude of effects are considered. This latter approach involves a more thorough consideration of sources of variability and uncertainty in the risk analysis.

5.1 Assessment Endpoints

Analysis of exposure pathways for used crankcase oils (UCOs) and subsequent identification of sensitive receptors were used to select environmental assessment endpoints. In this evaluation, the assessment endpoints of interest were adverse effects on populations of benthic species.

5.2 Environmental Risk Characterization

5.2.1 Dust Suppressant and Land Disposal

The dust suppressant and land disposal scenarios involve releases directly to the roadway and land. Since leakage from crankcase oils is a direct release to the roadway, new effects and exposure data from this source will be used as a surrogate for the dust suppressant and land disposal scenarios. In turn, pyrene, fluoranthene and phenanthrene will be used as representative components of UCOs to determine whether UCOs are harmful to the Canadian environment as defined under the Canadian Environmental Protection Act, 1999 (CEPA 1999).

In field situations, Landrum et al. (1991) suggested that for mixtures of polycyclic aromatic hydrocarbons (PAH), the toxic mode of action is additive, with no overt evidence of synergism or antagonism. This indicates that the molar concentration of a single PAH (e.g., pyrene) required to produce toxicity is the same if the PAH (pyrene) is the only substance in the sediment or if the PAH (pyrene) is found in a mixture with other PAHs in the sediment (Environment Canada, 1999). The toxicity of a complex substance can be determined by identifying constituents with similar modes of action and by calculating their joint toxicity (Environment Canada, 1997). Therefore, the ratio of each constituent concentration (EEV) and toxicity (ENEV) is calculated separately and reported as the Toxic Unit. The Toxic Units for pyrene, fluoranthene and phenanthrene will be summed to determine the total toxicity of these PAHs in UCOs.

5.2.1.1 Risk Analysis for Pyrene, Fluoranthene and Phenanthrene, and Total Toxicity

Concentrations of pyrene, fluoranthene and phenanthrene in St. Lawrence River sediment were identified as originating from UCOs. The conservative EEV for benthic organisms is 0.872 µg/g for pyrene, 1.238 µg/g for fluoranthene and 1.020 µg/g for phenanthrene and represents the highest reported concentration for these three PAHs that originates from UCOs (see Table 1) (Abrajano, 2000).

The most sensitive freshwater organism found in the literature was the benthic amphipod Hyalella azteca, with 95% mortality in mature adult males in a 28-day sediment toxicity test using field sediment at a concentration of 0.083 µg pyrene/g dry weight (Ingersoll et al., 1993). This study is considered as the CTV. The ENEV is determined by dividing the CTV by an application factor of 10 to account for inter- and intraspecies variability, uncertainty surrounding the extrapolation from a 95% mortality effect to a No-Observed-Effect Concentration (NOEC) and extrapolation from laboratory to field conditions. An additional application factor of 10 is used to account for the presence of other components of UCOs. Dividing the CTV of 0.083 µg/g dry weight by the resulting application factor of 100 yields an ENEV of 0.000 83 µg/g. The conservative quotient for pyrene, fluoranthene and phenanthrene is calculated by dividing the EEV by the ENEV for each of the three PAHs. Table 2 illustrates the development of this risk analysis.

5.2.2 Re-refining

No monitoring or effects data were available for this scenario. However, wastewater effluents and solid waste from re-refineries can be expected to contain trace metals, dissolved phenols, chlorinated solvents, PAHs and other organics, as well as suspended or emulsified oil (United States Environmental Protection Agency [U.S. EPA], 1974; Surprenant et al., 1983; Franklin Associates Ltd., 1985). Since PAHs, such as pyrene, fluoranthene and phenanthrene, are likely major components of the UCOs and if released into the effluent, then it is possible that the effluent could have direct effects on sediment biota and cause a change in species diversity.

5.2.3 Fuel

Emissions of heavy metals and PAHs from commercial combustion units are regulated by most provincial/territorial jurisdictions (see Appendix A). Concerns arise regarding smaller oil-burning space heaters that are not maintained and, as a result, cause emissions of heavy metals and PAHs to the environment. In a 1994 province-wide survey of space heaters (waste-derived fuel furnaces), 352 of 422 (i.e., 83%) were in non-compliance with the Ontario Ministry of Environment and Energy's Environmental Protection Act regulations (Ontario Ministry of Environment and Energy [OMEE], 1995). All 52 waste-derived fuel incinerators in eastern Ontario were out of compliance based on the results of this survey (OMEE, 1994). Reasons for non-compliance included failure to obtain a Certificate of Approval, paperwork burden and lack of maintenance of the space heaters. From discussions with provincial contacts, it is apparent that there are probably a few thousand of these units in use across Canada -- predominantly in service stations where oil changes are conducted. The level of compliance across Canada is not known. Pyrene, fluoranthene and phenanthrene found in the Arctic have been determined to originate mainly from the burning of oil, coal and wood (Barrie et al., 1997). Therefore, unmaintained combustion sources using UCOs may be contributing to PAH concentrations in the Arctic (Jensen et al., 1997).

5.2.4 Status of Canadian Provincial, Territorial and Federal Initiatives for Used Crankcase Oils

The concern over the hazardous nature of UCOs has been captured in various government initiatives, from guidelines to regulations, within Canada and internationally, to control the release of UCOs to the environment (see Appendices AppendixA and AppendixC).

Information from other jurisdictions indicates that reducing releases of UCOs to the environment is an important issue. Used oils (including UCOs), in general, are of concern to provincial, territorial, aboriginal and federal jurisdictions. The Canadian Council of Ministers of the Environment (CCME) has developed guidelines to control used oils, which include UCOs. Internationally, Canada, as a signatory to the Basel Convention, has agreed to control the movement of used oils, including UCOs, as a hazardous substance in order to protect human health and the environment. The Export and Import of Hazardous Wastes Regulations were the means by which Canada was able to ratify the Basel Convention and implement the conditions of the Organisation for Economic Co-operation and Development Council Decision (92)39/Final concerning the control of transboundary movements of wastes destined for recovery operations (see Appendix C). The main reasons for initiating controls were the leachable amounts of lead, PAHs and chlorinated hydrocarbons in the used oils, especially given the large volumes of used oils in circulation (Wittwer, 2000).

5.2.5 Other CEPA "toxic" substances

The following substances are listed under Schedule 1, List of Toxic Substances, of CEPA 1999 and are components of UCOs: arsenic and its compounds; benzene; cadmium; chromium and its compounds; acidic, sulfidic and soluble inorganic nickel and PAHs. Most of these substances were found to be CEPA "toxic" due to the exposure of sensitive organisms to them in the water or the sediment phase. The PAHs Assessment Report (Government of Canada, 1994b), in particular, identified a change in biodiversity of sediment-dwelling organisms as one of the reasons to conclude for CEPA "toxic." Other CEPA Schedule 1 substances also found in UCOs include lead (gasoline engine blow-by, from normal engine wear and as the additive, lead naphthenate) and trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane and polychlorinated biphenyls (PCBs) (as contaminants in collection activities). The presence of all of these substances in UCOs likely contributes to the toxicity of UCOs (Maltby et al., 1995b).

5.3 Sources of Uncertainty

There are several sources of uncertainty associated with the environmental assessment of UCOs. Due to the numerous possible sources of entry of UCOs into the environment, concentrations of UCOs in some areas in Canada could be higher than those identified. Concentrations of pyrene, fluoranthene and phenanthrene that were attributed to originating from UCOs were used to make the link to the presence of UCOs in the sediment. While these PAHs in sediments are from UCOs, it is not certain whether they originate totally from crankcases or originate from other sources, such as air deposition of combustion sources using UCOs as fuel or from vehicle exhaust emissions of UCOs. There were no acute or chronic toxicity studies for whole UCOs on benthic organisms. Therefore, the toxicity of UCOs constituents pyrene, fluoranthene and phenanthrene to benthic organisms was used as a surrogate for whole-UCO toxicity. There is uncertainty in the extrapolation from available toxicity data to potential ecosystem effects. To counter uncertainties in extrapolation, application factors were used in the environmental risk analysis to derive an ENEV.

5.4 Conclusion

Based on the findings of the analysis of data published between 1993 and 2000 on the exposure and effects of used crankcase oils to aquatic ecosystems, it is concluded that used crankcase oils are entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity. It is concluded that used crankcase oils be considered "toxic" under Paragraph 64(a) of the Canadian Environmental Protection Act, 1999 (CEPA 1999).