efsa-opinion-chromium-food-drinking-water

Chromium in food and drinking water
An additional contribution to the exposure to Cr(VI) was considered from the water used to
prepare certain foods (coffee, tea infusions, and dry infant and follow-on food mainly, but
also some others such as instant soup, evaporated and dried milk, and dehydrated fruit juice).
A worst-case scenario, which assumed there was no reduction of the Cr(VI) present in water
into Cr(III) when these foods are ingested immediately after their preparation. This scenario
led to an increase up to two-fold in the exposure levels to Cr(VI), in comparison to those
estimated via the consumption only of drinking water.
Non dietary exposure to trivalent and hexavalent chromium
The CONTAM Panel could not quantify the contribution of non-dietary exposure to Cr(III) or
Cr(VI) due to the existing uncertainties on the levels of exposure via inhalation, the
absorption rates of different chromium compounds via the respiratory system and the
relevance of different chromium species for non-dietary exposure.
The CONTAM Panel concluded that the exposure via the diet likely represents the most
important contribution to the overall exposure to Cr in the general population. Inhalation of
Cr compounds present in particular in cigarette smoke may contribute to the overall exposure
levels but the currently available information does not allow quantification of its relative
contribution.
Hazard identification and characterisation
Toxicokinetics
There can be differences in the bioavailability of chromium resulting from intake of different
forms of Cr(III) compounds, with organic complexes being somewhat more bioavailable, but
these differences are small and the overall bioavailability of trivalent chromium from all these
sources is low.
In contrast to Cr(III), Cr(VI) is able to cross cellular membranes.
The absorption and tissue distribution of Cr(VI) depend strongly on the rate and extent of its
reduction in the gastrointestinal tract but also on the ligands bound to Cr(VI) or the Cr(III)
formed upon reduction of Cr(VI). The data available so far support that reduction along the
gastrointestinal tract is efficient but that it cannot be excluded that even at low dose levels a
small percentage of Cr(VI) escapes gastrointestinal reduction to Cr(III).
Trivalent chromium
Repeated dose toxicity
Cr(III) displays very little (small decrease in body weight or body weight gain) to no toxicity
in experimental animals.
The relevant NOAELs were 506 and 286 mg Cr(III)/kg b.w. per day (the highest doses tested)
for the sub-chronic and long-term toxicity in the rat, respectively.
Developmental and reproductive toxicity
Conflicting results on reproductive effects of Cr(III) compounds have been reported. In the
studies where effects on reproduction or development were reported, the lowest LOAELs
were in the order of 30 mg/kg b.w. per day. The CONTAM Panel noted that a majority of the
studies have methodological limitations and were not designed for establishing reference
doses.
EFSA Journal 2014;12(3):3595 123