Prioritization for Detailed Assessment

The names of chemicals are fed into the initial lists for assessment via several routes on an ad hoc basis from within EPA, other agencies, public petitions, and in future from chemical industries (Muir, 1980). 

Restricted access to production and use information will limit the development of sound estimates of exposure and could weaken the assessment process. Also, the method of exposure evaluation favors chemicals of multiple routes of exposure over chemicals having an extremely high value for only one type of exposure. Property-effect relationships, toxicity models, and scoring systems are valuable when used at their specific level however, setting priorities for testing, which is a very complex task, still involves almost entirely subjective judgments of experienced researchers. 

The net concentration (exposure concentration) of the toxic chemical in the environment is given by equation (5) 

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