5. Human Health Risk Assessment

Exposure of humans to contaminated sites may result in many types of health damage ranging from relatively innocent symptoms such as skin eruption or nausea, on up to cancer or even death. Human health protection is considered as a major protection target, both by decision-makers as well as by the general public. The first step in Human Health Risk Assessment is definition of the problem (issue framing). In this stage, the scope of Human Health Risk Assessment must be clearly defined and the various stakeholders need to be actively involved. It is important to define the timeframe for which the Risk Assessment is applicable, since the effects depend on the duration of exposure and factors that impact human health risk will change over time. Subsequently, Exposure Assessment and Hazard Assessment must be performed. Ideally, the Exposure Assessment covers a smart combination of calculations, using exposure models, and measurements in contact media and body liquids and tissue (Biomonitoring). Hazard Assessment, which is different for contaminants with or without threshold effects, results in a Critical Exposure (aka: Toxicological Reference Value). In a final step, Risk Characterisation provides a risk appraisal calculated on the basis of exposure and hazard. Specific attention is given in this chapter to phenomena such as public perception, probabilistic Human Health Risk Assessment, Physiologically-Based PharmacoKinetic modelling, background exposure, sensitivity and uncertainty analyses, human health-based Soil Quality Standards, site-specific Human Health Risk Assessment on the basis of a tiered approach and ethical issues in regard to testing of human beings.