Appendix G: Glossary of Terms (Cont.)

Exposure point concentrations - estimates of the concentrations of the

contaminants of concern in environmental media to which the selected receptors

may be exposed along the completed pathways.

Exposure scenarios - detailed descriptions of a human receptor's activities which

result in exposure to the contaminants of concern; the pathway and route by

which the human receptor contacts contaminants of concern; physical, chemical,

and biological factors which affect the amount of the contaminant contacted or

ingested.

Indirect exposure pathways - ingestion of seafood (finfish and shellfish, from

marine or freshwater sources) which contains contaminants of concern.

LOAEL - the lowest concentration, dose, or body burden in a particular study for

which adverse effects are reported.

Measurement end points - discrete observations that can be related to the

assessment end point.

NOAEL - the highest concentration, dose, or body burden in a particular study

for which no observable adverse effects are reported.

Problem formulation - a systematic planning stage that identifies the major

factors considered in the assessment, and establishes its goals, breadth, and focus.

Receptors - humans or organisms that might be exposed to the contaminants via

direct or indirect pathways.

Reference dose - the toxicity value used most often in evaluating

noncarcinogenic effects, resulting from exposures to chemicals. Defined as an

estimate of a daily exposure level for the human population, including sensitive

subpopulations (such as elderly and children) that is likely to be without an

appreciable risk of adverse effects during a lifetime.

Representative human receptors - humans who have a complete exposure

pathway as described in the conceptual model, and whose exposure is likely to

represent a reasonable worst case exposure to the COCs.

Representative ecological receptors - organisms whose life histories and habitat

requirements fairly represent the range of habitats and life histories for those

organisms with complete exposure pathways found near the dredged material

management site.

Site characterization - a general description of the environmental setting.

Toxic end points - the type of effect (e.g., survival, growth, reproduction, etc.)

associated with each toxicity factor.

Toxicity factor - environmental concentration, dose, body burden, or dietary

concentration associated with a particular effect.

Appendix G Glossary of Terms