Hazard Identification 



The first step in the risk assessment process is to define toxicological 

 hazards posed by the chemical contaminants in samples of fish and 

 shellfish. These hazards are summarized in a toxicity profile for each 

 contaminant of concern. The EPA chemical database, IRIS, can be 

 easily accessed to obtain summaries of key toxicological data to include 

 in toxicity profiles. The results of the hazard assessment infiuence the 

 nature and extent of subsequent steps in risk analysis. For example, the 

 endpoint of concern in dose-response assessment may be selected 

 based on the most severe adverse effect identified in the hazard 

 assessment. In the absence of quantitative data for other steps in the 

 risk assessment process, the results of the hazard assessment constitute 

 the final product for a qualitative evaluation of risk. 



The contaminants of concern to be included in a particular risk assess- 

 ment should be selected based on the following criteria: 



• High persistence in the aquatic environment 



• High bioaccumulation potential 



• High toxicity to humans (or suspected high toxicity to humans 

 based on mammalian bioassays) 



• Known sources of contaminant in areas of interest 



• High concentrations in previous samples of fish or shellfish 

 from areas of interest. 



General information on persistence, bioaccumulation potential, and 

 toxicity may be obtained from references such as Lyman et al.(1982) 

 and Callahan et al. (1979). Other key sources that are periodically 

 updated are the Registry of Toxic Effects of Chemical Substances (e.g., 

 Tatken and Lewis 1983) and the Annual Report on Carcinogens (e.g.. 

 National Toxicology Program 1982, 1985). Specific information that is 



Contaminants of 

 Concern 



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