BfR | Annual Report 2013
66
Multiple residues of plant protection
products in food
“Poisonous cocktail in fruit and vegetables”, “Pesticides
are poisoning our food” – headlines concerning residues
of pesticides cause public worry time and time again,
whether due to the residues of individual substances or
multiple substances.
In principle, the permitted residue quantities may not
harm the health of consumers, even if multiple active
substances are ingested at once. In its pesticide and
biocide legislation, the EU therefore stipulates that mul-
tiple residues are to be given particular consideration.
Developing suitable methods for this is currently a great
challenge for chemical risk assessment. Since 2008, the
European Food Safety Authority EFSA has released nu-
merous publications on various issues in the area of so-
called cumulative risk assessment. The themes of these
publications include estimating exposure using distribu-
tion-based methods and the grouping of chemicals in
cumulative assessment groups.
Cumulative risk assessment should be carried out ac-
cording to the current state of scientific knowledge. But
it should also be simple and transparent so that it can
be used in routine procedures of regulatory practice. To
help achieve this goal, the BfR organised an international
workshop in March 2013. At this workshop, current scien-
tific knowledge on multiple residues was tested for its ap-
plicability in regulatory practice. More than 50 represent-
atives from science, research, public authorities, NGOs
and industry discussed their experiences to date and
identified unresolved issues. The discussions showed
that only assessment methods which are easy to imple-
ment are suitable for a standard application when setting
maximum residue levels and authorising plant protection
products or biocidal products. The official food surveil-
lance authorities must also be able to judge quickly and
safely whether a food sample with residues from several
chemicals represents a health risk for consumers. Mod-
els which demand extensive toxicological information,
the handling of large databases and complex calculation
procedures are not suitable.
In 2014, the BfR is developing a concept on how it is go-
ing to conduct cumulative risk assessment in legislative
procedures for plant protection products and biocidal
products and will test this on selected examples.
Recommendations for action on the assessment of
multiple residues of plant protection products:
1. The cumulative risk should first be assessed by
adding up the hazard quotients (HQ) of each active
substance, resulting in the hazard index (HI). This
method sufficiently protects consumers and can
be gradually refined if necessary with additional
toxicological information. The hazard quotient is a
suitable measure of the extent to which the residue
of an active substance ingested via food reaches
its toxicological limit values (ADI, ARfD).
2. The cumulative assessment groups, in which indi-
vidual substances are currently classified based on
their toxicological effect, should be further sub-
divided based on additional information regarding
their mechanism of action.
3. To estimate cumulative exposure in a regulatory
context, it would be preferable to use deterministic
methods.
4. The actual cumulative exposure of consumers by
pesticide residues should be regularly investigated
using data from food monitoring.
Residues of different plant protection products can occur
simultaneously in food, but their interaction must not impair
the health of consumers.
