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JECFA ASSESSMENT

Compared to our 1998 WHO/IPCS source document, in the JECFA evaluation, the food exposure assessments are more detailed, and newer data is used. The overall conclusion and message is rather similar. However, there is an important difference in the way the "tolerable intake" is expressed: in the IPCS evaluation it was expressed per day as a "tolerable daily intake" (TDI) whereas the JECFA evaluation expressed it per month as a "provisional tolerable monthly intake" (PTMI).

Although the values are in principle not very different, it is nowadays considered appropriate to express tolerable intakes on a longer basis than a daily one in the case of substances with cumulative properties (and long half-lives).

Dioxins

Table2. : Estimated tissue concentrations in human populations exposed to dioxin and dioxin-like compounds

Table 7: Estimated daily dietary intake of PCBs in the USA. a

JECFA ASSESSMENT

Dioxin Body Burden

Toxic Equivalents Scheme (TEFs & TEQs)

Daily Dioxin IntakesSome average daily intakes for long term exposures to dioxins:

Mass (weight) Units