Contents of the 

 Guidance Manual 



What Is Risk 

 Assessment? 



The risk analysis process consists of two distinct phases: risk 

 assessment and risk management. Risk assessment involves esti- 

 mating the scientific probability that an adverse health effect will 

 result from exposure to a toxic agent. Risk management entails 

 interpreting risk assessment results — scientific results — to formu- 

 late public policy. The National Estuary Program manual provides 

 technical guidance on risk assessment procedures; risk manage- 

 ment approaches, which involve policy decisions, are only briefly 

 discussed. Selecting policy alternatives is left to state and local 

 regulatory authorities. Public policy decisions based on risk 

 management could be any of the following: 



• Identifying locations as high-priority areas for environmental 

 cleanup; 



• Issuing public fish consumption advisories for certain areas; and 



• Banning fishing in certain areas. 



The National Estuary Program health risk assessment guidance 

 manual provides the following information: 



• A description of the risk assessment procedure for chemically 

 contaminated fish and shellfish; 



• Guidance on presenting and interpreting risk assessment 

 results; 



• A summary of assumptions and uncertainties of the recom- 

 mended procedure for risk assessment; and 



• An explanation of the dose-response values that are available 

 for individual chemicals, and of information sources for updating 

 these values. 



The document does not provide guidance on the risk management 

 issue of which level of risk is small enough to be acceptable, given 

 counterbalancing economic factors like consumer preference or 

 economic impacts on recreational and commercial fisheries. State 

 or local regulatory authorities will make case-by-case judgments 

 concerning restricting sportsfishing or issuing informational health 

 advisories even when fishing is not legally prohibited or limited. 



Risk assessments are limited by rudimentary scientific knowledge 

 of the effects of toxic chemicals on humans. Most of the present 

 information is developed by interpreting results of laboratory tests 

 on experimental animals like rats, mice, and primates for applica- 

 tion to humans. Although this extrapolation carries many uncertain- 

 ties, estimates of health risk can be used to formulate decisions 

 about actions to reduce risk. 



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