ABSTRACT
Contaminants in the environment occur in various physical and chemical forms and in close interaction with the environmental phases. The combination of environmental and contaminant characteristics is responsible for this interaction, which determines the contaminant’s accessibility. This interaction may be extremely strong in soil, sediment and other solid phase compartments. Mobility, i.e. volatility, water solubility and sorbability of a contaminant molecule and the bonding/sorption capacity of solid matrices together determine bioaccessibility, i.e. the probability of encountering and interacting with living organisms. Potential adverse effects on an ecosystem member are determined by another interaction between the environmental contaminant and the organism. A contaminant that can be taken up by an organism is called ‘bioavailable’. Bioavailability or biological availability determines the potential of a chemical substance to be absorbed by an organism. The potential of the organism to absorb, distribute and metabolize the chemical substance plays an important role in environmental risk. As far as humans are concerned, the gastrointestinal tract belongs to the ‘environment’, and digestion modifies the contaminant’s bioaccessibility by liberating the bond contaminant from the matrix.
