Tolerable daily intake (TDI) refers to the daily amount of a chemical that has been assessed safe for human being on long-term basis (usually whole lifetime). Originally
acceptable daily intake
Acceptable daily intake or ADI is a measure of the amount of a specific substance (originally applied for a food additive, later also for a residue of a veterinary drug or pesticide) in food or drinking water that can be ingested (orally) daily ove ...
(ADI) was introduced in 1961 to define the daily intake of a
food additive
Food additives are substances added to food to preserve flavor or enhance taste, appearance, or other sensory qualities. Some additives have been used for centuries as part of an effort to preserve food, for example vinegar (pickling), salt (salt ...
which, during the entire lifetime, appears to be without appreciable
risk
In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity with respect to something that humans value (such as health, well-being, wealth, property or the environme ...
.
For contaminants and other foreign chemicals not used intentionally, the term TDI is often preferred. Both ADI and TDI are usually assessed based on
animal experiments, and it is most often hundreds of times lower than the dose causing
no observable adverse effect (NOAEL) in the most sensitive tested animal species.
Because the confounding factors
In statistics, a confounder (also confounding variable, confounding factor, extraneous determinant or lurking variable) is a variable that influences both the dependent variable and independent variable, causing a spurious association. Con ...
(safety factors) may vary depending on the quality of data and the type of adverse effect
An adverse effect is an undesired harmful effect resulting from a medication or other intervention, such as surgery. An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. The term complica ...
, TDI values are not good estimates of the harmfulness of chemicals, and must be considered administrative tools to set allowable limits for chemicals, rather than scientific measures. The threshold limit value (TLV) of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse effects.
References
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Toxicology
fr:dose journalière tolérable
zh:每日耐受量
ja:耐容一日摂取量