efsa-opinion-chromium-food-drinking-water

Chromium in food and drinking water
SUMMARY
In March 2012, the European Food Safety Authority (EFSA) received a request from the Hellenic
Food Authority (EFET) for a scientific opinion on estimation of the risk to human health from the
presence of chromium (Cr) in food and Cr(VI) in bottled water.
Chromium is a metal widely distributed in the environment occurring in rocks, soil and volcanic dust
and gases. Chromium can exist in a variety of oxidation states, with the trivalent (Cr(III)) and
hexavalent (Cr(VI)) states being relatively stable and largely predominant. While Cr(III) is a natural
dietary constituent present in a variety of foods and also in dietary supplements, Cr(VI) most
commonly occurs in industrial processes and is present in drinking water usually as a consequence of
anthropogenic contamination.
At human dietary exposure levels chromium absorption is relatively low (< 10 % of the ingested dose)
and depends on its valence state and ligands. Most of the ingested Cr(VI) is considered to be reduced
in the stomach to Cr(III), which is poorly bioavailable and presents low ability to enter cells. In
contrast to Cr(III), Cr(VI) is able to cross cellular membranes. The interconversion of Cr(VI) to Cr(III)
is of relevance for risk assessment since, in general, Cr(VI) compounds are much more toxic than
Cr(III) compounds.
There are no maximum levels (MLs) for chromium in food. A parametric value of 50 μg Cr/L for total
chromium in water intended for human consumption and a Maximum Limit of 50 μg Cr/L for total
chromium in natural mineral waters are laid down in Council Directive 98/83/EC and in Commission
Directive 2003/40/EC, respectively.
The International Agency for Research on Cancer (IARC) has classified Cr(VI) compounds as
carcinogenic to humans (Group 1) with respect to the cancer of the lung and also cancer of the nose
and nasal sinuses based on evidence from occupational studies.
Following a call for data on chromium (trivalent and hexavalent) levels in food and drinking water
(water intended for human consumption and mineral waters), a total of 79 809 analytical results on
chromium were available in the EFSA database by the end of February 2013. A total of
27 074 analytical results were reported for food and 52 735 for all types of drinking water (including
e.g. tap water, bottled water and well water) covering the period from 2000 to 2012. Data were mainly
from 1 Member State although 11 other European countries were represented. Information on
oxidation state was not available for occurrence data in food, and for drinking water only 88 analytical
results were received on Cr(VI), all in bottled water.
Almost 50 % of the results on food samples were left-censored. After data cleaning and validation and
using different cut-offs based on the reported limits of quantification (LOQs), 24 629 analytical results
for food were considered for this assessment. At FoodEx level 1 all the food groups were well
represented, with a maximum of 4 647 samples in the food group ‘Vegetables and vegetable products
(including fungi)’. The five food groups of highest average chromium occurrence values were
‘Products for special nutritional use’, ‘Herbs, spices and condiments’, ‘Sugar and confectionary’,
‘Vegetables and vegetable products (including fungi)’, and ‘Animal and vegetable fats and oils’.
There is a lack of data on the presence of Cr(VI) in food. The EFSA Panel on Contaminants in the
Food Chain (CONTAM Panel) decided to consider all the reported analytical results in food as Cr(III).
This assumption was based on the outcome of recent speciation work, the fact that food is by-andlarge
a reducing medium, and that oxidation of Cr(III) to Cr(VI) would not be favoured in such a
medium.
However, the CONTAM Panel noted that if even a small proportion of total chromium in food was in
the form of Cr(VI), it could contribute substantially to Cr(VI) exposure.
Chronic dietary exposure to Cr(III) was estimated combining the food mean occurrence data with the
food consumption data at the individual level. Following the standard representation used for
CONTAM opinions, lower bound (LB) and upper bound (UB) mean chronic dietary exposure values
were calculated for Cr(III), across the different dietary surveys and age classes. Overall mean human
chronic dietary exposure ranged from a minimum LB of 0.6 to a maximum UB of 5.9 μg/kg b.w. per
EFSA Journal 2014;12(3):3595 2