Hazard Characterization for Lead in Human Populations

Chapter 21 Hazard Characterization for Lead in Human Populations... 

Part 4 continues with lead-specific discussions of the four components of a human health risk assessment as structurally articulated in 1983 by the NAS/NRC (1983) Chapter 21, human health hazard characterization for lead and diverse human populations Chapter 22, dose—toxic response relationships for lead in humans Chapter 23, illustrative uses of case- or setting-specific lead exposure characterizations and. Chapter 24, the last part of health risk assessment, the overall final and most quantitative step in actualizing (in a relative sense) the estimates of risk outcomes. 

Noted earlier in passing, lead is different from many toxic substances subjected to human health risk assessment methods in that the toxicant not only poses risk of disease but causes actual disease as well. What is more, this disease-producing substance works to do so in human populations as well as in experimental animals. This propensity of lead is amply characterized in a huge database that permits us to discover this duality and to integrate each form with the other. There are many hundreds and thousands of environmental contaminants which are not well characterized, so that we are left with quantifying hazards to human health in the form of calculated probabilities for harm using formulaic methodologies. 

The final step in the risk assessment methodology employed here for environmental contaminants is quantification of the extent of risks to health in various human populations. This step combines the general elements of hazard characterization and dose—toxic response relationships for lead with case-specific data quantifying the extent of toxic exposure to arrive at some quantitative value for risk. Various regulatory entities differ in the specifics of how this methodological template is applied but retain these broad features. 

---