Advisory Committee on Pesticides Annual Report 2001

<strong>Advisory</strong> <strong>Committee</strong> on Pesticides Annual Report 2001
agreed that the current default assumption that corn oil administration was an
acceptable model for dietary exposure was supported. It was suggested that,
if applicants wished to make a case for reduced bioavailability in respect of
specific crops and pesticides, the onus should be on them to submit data to
support such a case.
The <strong>Committee</strong> recommended that the research be submitted for publication
in a peer-reviewed scientific journal.
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Comparative risk assessment
The ACP was asked by Ministers to consider the value of comparative
assessment and substitution in the regulation of pesticides. At the July meeting
it was agreed that PSD should issue a consultation letter seeking views from
approval holders, users, consumers and environmental interests. Following
this, the ACP began to develop possible schemes for comparative assessment,
taking account of the responses to the consultation. During 2002, the
<strong>Committee</strong> will continue to consider these options, together with related issues
of relevance to the re-negotiation of the Pesticide Authorisation Directive
(91/414/EEC).
Degradation of chlorothalonil residues prior to analysis –
follow-up report
During Pesticide Residues <strong>Committee</strong> (PRC) routine monitoring in 1994, it was
noted that fortified residues of chlorothalonil were being ‘lost’. A study was
initiated to examine the extent and possible mode of the degradation in five
crops: lettuce, onion, celery, broccoli and lemon.
The study was considered at the November 1994 ACP meeting. The results
showed that significant losses were occurring as a result of comminution and
freezer storage and/or storage of extracts at room temperature prior to
analysis. These losses were greatest in lettuce, celery and onions and less in
broccoli and lemons. If lettuce was ‘killed’ by microwaving prior to storage
and analysis, losses were greatly reduced, indicating that the problem was
likely to be enzymatic degradation. The ACP had recommended that a further
study be conducted on the fate of chlorothalonil residues during processing
and analysis of lettuce and onions.
The follow-up study was considered at the June 1997 ACP meeting. The
results showed that losses of chlorothalonil and also dichlofluanid could be
minimised by cryogenic milling of lettuce samples and extracting the subsamples
partially frozen. In the case of onions, the use of cryogenic milling