Technical approach for rapid screening of substances of lower ecological concern: discussion


The results of application of the rapid screening approach to substances that were identified as substances that are persistent and inherently toxic to non-human organisms (PiT) or substances that are bioaccumulative and inherently toxic to non-human organisms (BiT) through the categorization process and which are believed to be in commerce at low quantities are discussed in a separate documentFootnote 5.

It is recognized that conclusions resulting from use of this approach have associated uncertainties, as the approach makes use only of data that is relatively easy to obtain. However, it is believed that the number of false negative conclusions will be low, due to the use of a wide range of filters relating to both use quantity and ecological hazard concerns identified for a substance, as well as the use of different conservative exposure scenarios.

Rapid screening is based in part on use and quantity data that were submitted when the Domestic Substances List (DSL) was first created 20 years ago. In many cases, the age of this information adds uncertainty in making decisions about whether and how to manage a given substance without investing in the collection of new information. By contrast, the US Toxic Substances Control Act mandates a regular update (every five years) of the quantities and uses of each of the substances on its equivalent to the DSL. Adoption of a similar requirement in Canada, as announced in December 2006 by the Government as part of the Chemicals Management Plan, will ensure that the most current information is available for decision making. Conclusions resulting from application of this rapid screening approach will be revisited as new information on quantities and uses becomes available.

In the meantime, it is important to recognize that the Government of Canada uses seven different "feeders" (categorization, new substances notifications, industry submissions, international assessment and data collection, emerging science, public nominations, and provincial or international decisions) to identify existing substances that may require assessment under the Canadian Environmental Protection Act, 1999 (CEPA 1999). Substances may be subject to assessment whether or not they meet categorization criteria, and whether or not the Existing Substances Program has previously concluded that the substance did not meet criteria in section 64 of CEPA 1999.

The Government of Canada would like to emphasize that while the categorization process is an important mechanism to set priorities, information from the other six feeders will continue to be collected and evaluated, on an on-going basis. Substances that are identified through these other feeder mechanisms will be integrated into the prioritization scheme along with other substances that have been identified through categorization as priorities for assessment.

Substances for which it is proposed, based on the outcome of the rapid screening approach and other considerations, that they do not meet the criteria in section 64 of CEPA 1999 and that no further action is required at this time, remain subject to re-assessment if information is identified that indicates that further evaluation of the substance is warranted. Examples of the types of information that may trigger further evaluation of a substance include:

  • Evidence of higher quantities in commerce. Since the rapid screening approach is driven in part by use quantity information, updated information suggesting that higher quantities of a substance are now in use could indicate that a substance should be subject to further evaluation.
  • Evidence of higher releases. The exposure scenarios used assumptions that are expected to be conservative for most substances. Updated information indicating that the assumed conditions are not protective for a particular substance owing to its routine handling and use could indicate that a substance should be the subject of further evaluation.
  • Evidence of ecological exposure. Monitoring data demonstrating the detectable presence of a substance in environmental media could indicate that a substance should be the subject for further evaluation.
  • Evidence of other possible ecological risk. Information that was not considered in the rapid screening approach, but that could be of significance in establishing an ecological risk from a substance could trigger further evaluation of the substance.
  • Evidence that a substance is a substances that are persistent and bioaccumulative and inherently toxic to non-human organisms (PBiT). Since PBiTs are not candidates for the rapid screening approach, any information to suggest that the substance is PBiT could trigger further evaluation of the substance.
  • Identification as part of a category undergoing assessment. If the substance is part of a group that is prioritized for a category assessment at some time in the future, the substance may be subject to this further evaluation.

Information of these types may be identified from a number of different sources, including:

  • direct submission of information by stakeholders;
  • research, monitoring and DSL update activities taking place under the Federal Chemicals Management Plan;
  • other assessment or regulatory activities in Canada or in foreign or international forum.
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