RESIDUE AND ANALYTICAL ASPECTS
Diazinon was first evaluated by the 1965 JMPR and has been reviewed several times since. In 1993 a periodic review was conducted and in 1994 a new MRL was recommended for hops. The 1993 JMPR recommended, among other items, an increase in the CXL for pome fruits from 0.5 to 2 mg/kg and the withdrawal of the CXLs for animal commodities in the absence of animal transfer studies and data from uses to control ectoparasites.
The CCPR in 1995 and 1996 endorsed most of the recommendations of the 1993 JMPR with the exception of the proposed MRL for pome fruits and the recommended withdrawal of the CXLs for milks and the meat of cattle, pigs and sheep. The main focus of the present evaluation was the review of new submissions in support of MRLs for animal products: the Meeting also estimated STMR levels for pome fruits, tomatoes and cabbages (0.12, 0.12 and 0.16 mg/kg respectively) for dietary intake predictions, on the basis of data published in the 1993 Evaluations, in response to concerns raised at the CCPR. The Meeting understood that new trials according to current (revised) US GAP might support a lower MRL for pome fruits than the 1993 JMPR recommendation. The manufacturer expects to be able to submit data from these trials together with the relevant GAP when reports of new supervised trials with diazinon used for the control of ectoparasites are submitted in 1998.
The Meeting reviewed information on current GAP, new and previously submitted metabolism studies and analytical methods, new residue transfer studies with poultry and cattle, and new and previously submitted data from supervised trials of ectoparasite control in cattle and sheep using a variety of application methods. Many of the older supervised trials were not acceptable by current standards and in most cases acceptable data were available only for single treatments whereas GAP allows multiple applications. The Meeting was able to estimate a number of maximum residue levels, but considered additional information on GAP to be highly desirable.
Maximum residue levels recommended for use as MRLs, together with estimated STMR levels, are recorded in Annex I.
FURTHER WORK OR INFORMATION
Desirable
1. Studies of the stability of diazinon, diazoxon and hydroxydiazinon in stored analytical samples of meat, fat, edible offal, milk and eggs.
2. Modem dipping and spray trials on sheep and cattle at maximum GAP rates and including multiple dips and sprays. Analyses for diazinon residues in milk, muscle, edible offal and fat (kidney, omental and especially subcutaneous fat) would be desirable, as well as analyses for diazoxon and hydroxydiazinon in addition to diazinon.
3. Data from monitoring analyses of subcutaneous fat of sheep for diazinon, ideally sheep known to have received multiple dip or spray applications at maximum GAP rates.
4. Submission, when the new supervised trials of ectoparasite control are submitted in 1998, of information on current US GAP for pome fruits and cabbages and data from recently completed US supervised trials reflecting that GAP.
