Hazard Assessment and Contaminated Sites - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 561

Epidemiology The study of the distribution and determinants of health related
states or events in specified populations, and the application of the study to the
control of health problems (Last 1988 )
Expert An expert has (1) training and experience in the subject area resulting in
superior knowledge in the field (2) access to relevant information, (3) an ability to
process and effectively use the information, and (4) is recognised by his or her peers
or those conducting the study as qualified to provide judgements about assumptions,
models, and model parameters at the level of detail required (NCRP 1996 ).
Exposure Contact of a contaminant, physical or biological agent with the outer
boundary of an organism, e.g., Inhalation, ingestion or dermal contact.
Exposure Assessment The estimation (qualitative or quantitative) of the magni-
tude, frequency, duration, route and extent (for example, number of organisms) of
exposure to one or more contaminated media for the general population, for different
subgroups of the population, or for individuals.
Exposure Route The way a contaminant enters an organism after contact e.g., By
ingestion, inhalation, or dermal absorption (EPA 1992 , p. 22933).
Extrapolation For dose-response curves, an estimate of the response at a point
outside the range of the experimental data. Also refers to the estimation of a response
in different species or by different routes than that used in the experimental study of
interest.
Factor A single factor or product of several single factors used to derive an
acceptable intake. These factors account for adequacy of the study, interspecies
extrapolation, inter-individual variability in humans, adequacy of the overall data
base, nature and extent of toxicity, public health regulatory concern and scientific
uncertainty.
Gene The DNA molecule of inheritance of characteristics including susceptibility
to disease.
Genotoxic Agents for which a direct activity is the alteration of the information
encoded in genetic material (Butterworth 1990 )
Genotoxic carcinogen A contaminant which induces tumours via a mechanism
involving direct damage to DNA (IEH 1999 ).
Genotoxicity A broad term describing the ability to produce damage to the genetic
material (DNA) of cells or organisms.
Guidance Values “Values such as concentrations in air or water, which are derived
after appropriate allocation of Tolerable Intake (TI) among the possible different
media of exposure. Combined exposure from all media at the guidance values over
a lifetime would be expected to be without appreciable health risk. The aim of a
guidance value is to provide quantitative information from Risk Assessment for risk
managers to enable them to make decisions concerning the protection of human
health.” (WHO 1994 , p. 16)