Protocol for the Derivation of Environmental and Human ... - CCME

Soil: Normally defined as the unconsolidated material on the immediate
surface of the earth that serves as a natural medium for
terrestrial plant growth. Here limited to unconsolidated, surficial,
mineral materials.
Soil-dependent organisms: Organisms that use the soil medium as
primary habitat, have direct contact with soil, and require soil to
sustain normal biological function. In this document, these
organisms are limited to plants, invertebrates, and
microorganisms.
TTT
Teratogenicity: The ability of a chemical to change the normal
development processes of an unborn organism, resulting in
permanent alterations in the biochemical, physiological, or
anatomical functions of the organism.
Texture: Categorical description of the proportions of sand, silt, and
clay present in a soil.
Threshold: The dose/concentration of a chemical below which no
adverse effect is expected to occur.
Tolerable daily intake: The level/rate of chemical exposure to which a
person may be exposed with no expected adverse effects. A
tolerable daily intake can only be determined for chemicals with
threshold effects (i.e., non-carcinogens).
Tolerable incremental exposure: The additional exposure which a
person may experience, over and above background estimated
daily intake, but not exceeding the tolerable daily intake for that
substance.
Toxic: Adverse effect (e.g., reduced survival of a population, growth
inhibition, or reduced reproduction rates) which occurs in an
organism, or population of organisms due to exposure to a
contaminant.
Trophic level: Position in the food chain determined by the number of
energy transfer steps to that level.
UUU
Uncertainty factor: See safety factor.
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