Rapid Screening of Substances of Lower Ecological Concern

Summary of the Rapid Screening Approach

The rapid screening approach uses a series of both qualitative and conservative quantitative steps to efficiently evaluate the likelihood that a substance may cause ecological harm. At each of the steps shown in Figure 1, substances for which there may be potential to cause harm are identified as requiring further screening assessment beyond the rapid screening approach. For those substances that proceed through all steps of the approach without being thus identified, it is concluded that they are unlikely to cause ecological harm and, as such, do not at this time meet the criterion set out in paragraph 64(a) of CEPA 1999.

Figure 1: Overview of the rapid screening approach

Overview of the rapid screening approach

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The first step consists of determining if substances belong to categories that have been identified for evaluation as part of a category assessment. These substances are identified at this step as requiring further screening assessment beyond the rapid screening approach, and do not proceed to step 2.

The second step involves applying different exposure scenarios through the use of environmental fate models. First, two generic aquatic exposure scenarios are considered to identify potential concerns near the point of discharge of a substance to the environment. A regional multi-media model named RAIDAR (Risk Assessment, Identification And Ranking) is also applied to identify potential concerns in different environmental media, as well as in food chains.

The third step involves a mechanical process to identify whether or not a substance appears on different lists or in sources of information relating to hazard or exposure (including quantity in commerce). This flags substances that have been identified by domestic or international initiatives as being of greater concern due to their hazard properties, or which may now be in commerce at greater quantities than is believed to be the case based on the available information.

Depending on the nature of the information sources, substances flagged by the mechanical process may be concluded as requiring further assessment beyond rapid screening, or may be further evaluated within rapid screening using a "manual process". The latter involves case-by-case evaluation to decide, for example, whether the information in the source that flagged the substance is relevant to the situation in Canada. This may also involve collection and review of information from other sources that are not as amenable to evaluation using a mechanical approach. The manual process involves evaluation of the weight and relevance of information obtained from the full range of sources identified.

A detailed description of the approach is contained in a separate document (Environment Canada, 2007a).

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