Sugar beet. Two processing studies were carried out and no residues of haloxyfop (<0.01 mg/kg) were found in sugar derived from sugar beet containing 0.07 and 0.11 mg/kg.
The Meeting estimated an STMR-P of 0.002 mg/kg for haloxyfop in sugar.
The concentration factors for pressed pulp were 0.36 and 0.43. The Meeting estimated an STMR-P of 0.008 mg/kg for haloxyfop in pressed pulp by applying the mean concentration factor (0.4) to the sugar beet STMR of 0.02 mg/kg.
Soya beans. Concentration factors from 4 trials were 0.75, 1.19, 1.25 and 1.31 for meal, 0.375, 0.41, 0.79 and 1.25 for crude oil and 0.33, 0.375, 0.75 and 1.22 for refined oil, giving mean factors of 1.13, 0.71 and 0.67 respectively. The Meeting estimated STMR-P levels of 0.03, 0.02 and 0.02 mg/kg for meal, crude oil and refined oil respectively by calculation from the STMR for pulses (0.03 mg/kg).
Rice. The residues in rice bran from normally treated rice were <0.02 mg/kg, and the Meeting estimated an STMR-P of 0.02 mg/kg for rice bran, unprocessed.
Cotton seed. Concentration factors for crude oil from 3 trials were 0.88, 1.0 and 1.6, giving a mean of 1.16. The Meeting estimated an STMR-P of 0.10 mg/kg for crude oil from the STMR for cotton seed of 0.09 mg/kg.
Rape seed. Concentration factors from 4 trials were 0.72, 0.89, 0.92 and 0.93 for meal or cake and 1.43, 1.97, 2.34 and 2.79 for crude oil (residues in pressed oil were not used for calculation of the concentration factors because the process is not current commercial practice). The factors for refined oil were 1.07 and 2.19. The Meeting estimated STMR-P levels of 0.15, 0.36 and 0.28 mg/kg for meal, crude oil and refined oil from the mean concentration factors of 0.87, 2.13 and 1.63 respectively and the STMR for rape seed of 0.17 mg/kg.
Note - Correction to report of 1995 JMPR
The concentration factors of 1.7 for crude oil and 2.1 for refined oil should be replaced by 2.13 for crude and 1.63 for refined oil.
Products of animal origin
Cattle. The Meeting was aware that the dosing levels in the feeding studies evaluated by the 1995 JMPR were expressed on a dry-weight basis, whereas the provisional maximum residue levels for the feed items were estimated on a wet-weight basis. The Meeting therefore reconsidered the conclusions of the 1995 Meeting with respect to residues in cattle products.
Fodder beet, alfalfa, pasture, sugar beet tops, pulses, rape fodder and processed fractions of oil seed and sugar beet can be used as feed for beef and dairy cattle, but the maximum haloxyfop intake would result from consuming 100% of pasture. The maximum residue found in pasture was 3.35 mg/kg (1995 Residue Evaluations, p.488), and with an assumed 80% moisture content this would be equivalent to 16.75 ppm in the feed on a dry-weight basis.
Since this feed level is higher than the highest level in the feeding studies (beef calves 10 ppm; lactating cows 2.5 ppm), the Meeting could not confirm the maximum residue levels for cattle products that were estimated by the 1995 JMPR and agreed to withdraw the provisional estimates for these commodities.
Poultry. Pulses and processed fractions of pulses and oil seed can be used as feed for poultry. Cereals are the main feed items, but the feed could contain up to 50% of pulses, 7% of rape seed meal and 30% of soya bean meal, and this composition would provide the maximum haloxyfop intake. The median intake level for this feed composition was calculated from the STMR for each feed item (pulses 0.03 mg/kg, rape seed meal 0.15 mg/kg and soya bean meal 0.03 mg/kg) to be 0.035 ppm (dry weight basis).
The residues in the muscle, liver, fat and eggs at a feeding level of 0.035 ppm were estimated from control residues (<0.01 mg/kg in each product) and the highest residues found in each product in the feeding study at 0.25 ppm by extrapolation to be <0.01, 0.01, 0.01 and <0.01 mg/kg respectively.
The Meeting confirmed the 1995 estimates of maximum residue levels in poultry products and estimated an STMR of 0.01 mg/kg for haloxyfop in chicken meat, chicken edible offal and chicken eggs.
Residues in rotational crops
Comprehensive studies were conducted with six rotational crops, using labelled or unlabelled haloxyfop. When lettuce, sugar beet and wheat were planted as rotational crops 25-148 days after treating soya beans or cotton as primary crops with unlabelled haloxyfop at a rate of 0.28 or 0.56 kg ai/ha, no residues were found in any of the mature rotational crops except green wheat forage at the LOD of 0.01 mg/kg, 110 days after treatment with 0.28 kg ai/ha. The limit of determination was 0.01 mg/kg for all substrates except wheat straw, for which it was 0.02 mg/kg.
When lettuce, wheat, soya beans, carrots or turnips were grown to maturity in soil which had been treated with phenyl-ring-labelled haloxyfop at 0.56 kg ai/ha 30 days before planting, the highest radioactive residues in the edible portions were found in lettuce and wheat grain and were 0.01 mg/kg haloxyfop equivalent. The radioactivity was too low for identification of the residue. 130 days after treatment of soya bean plants with phenyl-ring-labelled haloxyfop, the top 5 cm of soil was transferred to pots and sown with lettuce, soya bean, wheat and sugar beet in the laboratory. The total radioactivity was 0.01, 0.04, 0.02 and 0.01 mg/kg haloxyfop equivalent in lettuce, soya bean, wheat and sugar beet respectively and 0.02, 0.05, 0.02 and 0.02 mg/kg in soya bean forage, soya bean straw, wheat straw and sugar beet forage respectively. Again, the residue could not be identified owing to the low level of radioactivity.
The pyridinol 3-chloro-5-trifluoromethylpyridin-2-ol was found in soil as a major terminal degradation product under aerobic conditions (1995 Residue Evaluations, p.415) but it was not detected in the plants at harvest in any of the plant metabolism studies, although these included experiments with pyridinol-labelled haloxyfop.
The submitted data indicated that haloxyfop and its soil degradation products would not be absorbed or accumulate in plants to any significant extent.
The Meeting noted that the residues found in supervised trials on fodder crops reviewed by the 1995 JMPR were expressed on a wet-weight basis, although the Codex Classification of Food and Feeds indicates that MRLs for fodder and forage should preferably be set and expressed on a dry-weight basis. As the Meeting did not have information on the moisture content of the fodder crops for which the 1995 JMPR estimated provisional maximum residue levels, it agreed to withdraw the provisional estimates for fodder crops.
