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Tolerable Daily Intake

Similar term(s): TDI.

Definition:

A TDI is an estimate of the amount of a substance in air, food or drinking water that can be taken in daily over a lifetime without appreciable health risk. TDIs are calculated on the basis of laboratory toxicity data to which uncertainty factors are applied.

TDIs are used for substances that do not have a reason to be found in food (as opposed to substances that do, such as additives, pesticide residues or veterinary drugs in foods- see ADI).

Source: GreenFacts

More:

For most kinds of toxicity, it is generally believed that there is a dose below which no adverse effect will occur. For chemicals that give rise to such toxic effects, a tolerable daily intake (TDI) should be derived as follows, using the most sensitive endpoint in the most relevant study, preferably in drinking water:

TDI = (NOAEL or LOAEL) / UF

Where:
NOAEL = no-observed-adverse-effect-level
LOAEL = lowest-observed-adverse-effect-level
UF = Uncertainty factor

As TDIs are regarded as representing a tolerable intake for a lifetime, they are not so precise that they cannot be exceeded for short periods of time. Short-term exposure to levels exceeding the TDI is not a cause for concern, provided the individual’s intake averaged over longer periods of time does not appreciably exceed the level set. The large uncertainty factors generally involved in establishing a TDI (see below) serve to provide assurance that exposure exceeding the TDI for short periods is unlikely to have any deleterious effects upon health. However, consideration should be given to any potential acute effects that may occur if the TDI is substantially exceeded for short periods of time.

Source: FAO/WHO  Drinking water - derivation of chemical guideline values

Related words:

Acceptable Daily Intake - Biologic intake - Biologic uptake - LOAEL - NOAEL - Threshold (in an ecosystem) - Uncertainty factor

Translation(s):

Deutsch: Tolerierbare tägliche Aufnahmemenge
Español: Ingesta Diaria Tolerable
Français: Dose journalière tolérable

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