Human exposure
assessment is one of the key components in the health risk assessment (RA) paradigm
formulated by the National Research Council (1983, 1994). Its importance and relevance
were brought up repeatedly in the previous lectures. In these next two lectures, students
will be given a detailed description and an expanded discussion on the techniques and
methods used for this important RA component.Lecture 7 will focus on the (presumably
more) direct measurements used in human exposure assessments, primarily those based on the
use of some form of biological monitoring. With biological monitoring of exposure, the
health risk can be assessed through the evaluation of the internal dose in individuals. If
the internal dose could be measured accurately and precisely, then such a quantity would
account for the exposure from all practical sources.
Since the internal dose cannot be measured in every case or for all human exposures,
measurements of the external dose become necessary in RA. External doses can be
extrapolated from assumed contact rates where applicable, and the agent’s ambient
(environmental) concentrations in air, food, water, soil, and clothing. In some cases, the
exposure will be measured even more indirectly using survey results, employment histories,
medical records, and the like. These indirect measurement methods will be the topics of
Lecture 8.
