Chapter 6: Exposure Assessment

characterization of chemical exposure problems
–process used to
1. establish the presence or absence of chemical hazards
2. delineate the nature and degree of the hazards
3. determine possible human health threats posed by the exposure or hazard situation
important factors in exposure assessment
–routes of exposure
–nature and behavior of chemical substances

–used to estimate rates at which chemicals are absorbed by the potential human receptor given a specific scenario

factors affecting human exposure to chemical hazards
–routes of exposures
–chemical translation from environmental concentration to absorbed concentration
–spatial and temporal issues (same location?, same time frame and duration?)
–the amount of chemical coming into contact with a receptor’s visible exterior body or with the abstract/conceptual exchange boundaries
–amount of chemical absorbed by the body into the bloodstream
chronic daily intake
–measures long-term exposures, is based on the number of events that are assumed to occur within an assumend lifetime for potential receptors
subchronic daily intake
–projected receptor exposures over a short-term period (subchronic non-carcinogenic effects)
–fraction of the chemical that desorbs from its matrix in the GI tract and therefore is available for absorption
–describes the transfer of a chemical across a biological membrane into the blood circulation
–fraction of a chemical that is taken up by the body’s circulatory system relative to the amount that an organism is exposed to during an exposure scenario
bioavailability of COC
–multiply the fraction of the chemical that is bioaccessible and the fraction that is absorbed
–bioaccessibility (typically a %)
–absorption factor (typically a % or can be turned into a %)