Toxicity 



• Is the contaminant toxic? -- hazard identification 



• How potent is the contaminant as a toxicant? -- dose-response 

 assessment and questions of exposure; e.g.: 



• What is the concentration of the pollutant in the fish? 



• What is the extent of consumption of the fish by what popula- 

 tions? 



Much of the information relevant to the first two questions above is 

 available from either EPA or FDA and need not be generated by the 

 states. For example, information on the toxicity of pesticides is avail- 

 able from EPA. Further, EPA has developed its Integrated Risk 

 Information System (IRIS), which is a source of EPA risk assessment 

 information on hundreds of chemicals accessible to the states by 

 electronic-mail. The RfDs (ADIs) and carcinogenic potency factors 

 found in IRIS, represent evaluations of a wide body of scientific 

 literature, case-by-case judgments on difficult issues (e.g., the ade- 

 quacy of the studies and their relevance to humans), and general 

 science policy positions (e.g., the advisability of combining of benign 

 and malignant tumors). In many cases, the agencies' toxicity evalua- 

 tions and policy positions have benefited from widespread peer-review 

 and scientific consensus at the national and international level. Such 

 information should be directly useful to the states. 



It should be noted that differences in approaches to risk assessment 

 remain at the federal level. One area of particular interest is that of 

 carcinogenicity risk assessment. To narrow the range of uncertainties 

 and inconsistencies in this area as much as possible both EPA and FDA 

 have officially adopted the "OSTP Cancer Principles" as the basis for 

 their carcinogen risk assessments ("Chemical Carcinogens: A Review 

 of the Science and its Associated Principles", OSTP 1985). These 

 general principles were developed to provide interim guidance in areas 

 of uncertainty until such time that additional scientific data provided 

 the information needed to improve estimations of risk in human 

 populations. The OSTP document was written in the light of the 

 decisionmaking processes used by EPA and FDA and should be 

 consulted for additional details. An application of the OSTP Principles 

 to use at EPA can be found in the Agency's Guidelines for Cancer Risk 

 Assessment (FR Vol. 51, 33992-34003, September 24, 1986). 



Remaining differences between EPA and FDA in important risk 

 assessment assumptions continue to be discussed and explored, both 

 in discussions between staff members of the two agencies. The goal is 

 to move toward a common position which has a firmer scientific basis. 

 A detailed description of EPA's hazard identification and dose- 

 response assessment processes for both cancer and non-cancer effects 

 can be found in the main text of this guidance manual. 



Exposure 



The exposure information necessary to provide local answers to the 

 latter two questions posed at the beginning of this section is the 

 responsibility of federal agencies only when they have primary respon- 



