Hazard Assessment and Contaminated Sites - Dealing with Contaminated Sites: From Theory Towards Practical Application - page 559

Adverse Effect The change in morphology, physiology, growth, development or
life span of an organism which results in impairment of functional capacity or
impairment of capacity to compensate for additional stress or increase in susceptibil-
ity to the harmful effects of other environmental influences. Some adaptive changes
are not generally considered to be adverse e.g., some changes in enzyme levels.
Agent Any chemical, physical, biological or social substance or factor being
assessed, unless otherwise noted.
Applied Dose Amount of an agent presented to an absorption barrier and available
for absorption. The amount may be the same or more than the absorbed dose.
Bias A process resulting in a tendency to produce results that differ in a systematic
value from the true values. Also known as systematic error (Beaglehole et al. 1993 ).
BMD Benchmark Dose. The dose associated with a given incidence (e.g., 1%, 5%
or 10% incidence) of effect, the Benchmark Risk, based on the best-fitting dose-
response curve.
Bioavailability The ratio of the systemic dose to the applied dose.
Carcinogen Chemical, biological or physical cancer-causing agent.
Carcinogenesis The origin, causation and development of tumours. The term
applies to all forms of tumours (e.g., Benign and malignant).
Carcinogenicity The ability to produce tumours, which may be benign or
malignant (IEH 1999 ).
Chronic toxicity The ability to produce an adverse effect which persists over a
long period of time, whether or not it occurs immediately upon exposure to a con-
taminant or is delayed, or an effect which is only induced by prolonged exposure to
a contaminant (IEH 1999 ).
Confidence Weight assigned by the evaluator to the quality of the information
available (high, medium or low confidence) to indicate that a contaminant possesses
certain toxicological properties.
Confidence Limits A range of values determined by the degree of presumed
random variability in a set of data, within which the value of a parameter, e.g.,
The mean, lies, with a specified level of confidence or probability (e.g. 95%). The
confidence limit refers to the upper or lower value of the range (DOH 1991 ).
Confounding Factor A factor that distorts the apparent effect or magnitude of the
effect of a study factor or risk. Such factors must be controlled for in order to obtain
an undistorted estimate of a given effect (DOH 1991 ).
Critical Effect(s) The adverse effect judged to be the most important for setting
an acceptable human intake or exposure. It is usually the most sensitive adverse
effect, i.e., that with the lowest effect level, or sometimes a more severe effect, not
necessarily having the lowest effect level (IEH 1999 ).