PESTICIDE RESIDUES IN FOOD - 1980
Sponsored jointly by FAO and WHO
EVALUATIONS 1980
Joint meeting of the
FAO Panel of Experts on Pesticide Residues
in Food and the Environment
and the
WHO Expert Group on Pesticide Residues
Rome, 6-15 October 1980
2,4-D
Explanation
At the 1978 Meeting of the Codex Committee on Pesticide Residues
(CCPR) the United States of America, The Netherlands and Argentina
considered the 0.2 mg/kg MRL for raw grain, recommended by the 1975
Joint Meeting too low to accommodate the use of 2,4-D to control
weeds shortly before harvest and proposed a 0.5 mg/kg MRL for raw
grain (barley, oat, rye, wheat). Other delegations favoured a
lower MRL. Governments were asked to send data for consideration by
the JMPR. As no data were submitted to the JMPR the MRL was not
changed and the proposal was advanced to Step 8 at 11th Session of
CCPR in 1979.
The residue data on which the MRL was based were reconsidered by
the present Meeting, together with additional information from the
U.S.A., especially on the occasional use of 2,4-D as a harvest aid
(to control weeds and to facilitate machine harvesting) for small
grain.
RESIDUES IN FOOD
RESIDUES RESULTING FROM SUPERVISED TRIALS
Information contained in the 1975 Joint Meeting Evaluations
(FAO/WHO, 1976) indicated that the occasional use of 2,4-D in small
grain shortly before harvest can result in residues up to 0.4 mg/kg
at recommended application rates of 1.5 kg/ha (or below) and
pre-harvest intervals of at least 14 days.
Further data resulting from supervised trials carried out before
1975 and provided by the U.S.A. (USDA, 1980) are given in Table 1.
Residues range up to 0.36 mg/kg when good agricultural practice is
followed.
Table 1. Residues of 2,4-D in Small Grain1
Type and rate of Pre-harvest Residues of 2,4-D
application (kg/ha) interval (days) (mg/kg)
Dimethylamine salt
1 7 0.06 0.29
1 14 0.15 0.31
2 7 0.39
2 14 0.50
Iso-propyl ester
1 7 0.14 0.22
1 14 0.09 0.15
2 7 0.21 0.49
2 14 0.31 0.31
Iso-octyl ester
1 7 0.18 0.26 0.36
1 14 0.23 0.23 0.35
2 7 0.35 0.45
2 14 0.63
1 Barley, oats and wheat only.
APPRAISAL
Residues of 2,4-D in or on cereal grains were last considered by the
1975 Joint Meeting and an MRL of 0.2 mg/kg in raw grain was
recommended. The residue data on which this MRL was based were
reconsidered by the present Meeting together with additional
information from the U.S.A., especially on the occasional use of 2,4-D
as a harvest aid (to control weeds and to facilitate machine
harvesting) for small grains.
At recommended dosages up to 1.5 kg/ha and a pre-harvest interval of
14 days, 2,4-D residues on barley, oats, rye or wheat range up to
about 0.5 mg/kg grain. The available residue data provided a basis
for increasing the MRL for these cereals to 0.5 mg/kg. The MRL of 0.2
mg/kg was retained for other cereal grains.
RECOMMENDATIONS
The meeting concludes that the maximum residue levels listed below are
suitable for establishing MRLs to replace the previously recommended
MRL for raw grain.
Pre-harvest intervals on
Commodity Level (mg/kg) which levels are based
Barley 0.5 14 days
Oats 0.5 14 days
Rye 0.5 14 days
Wheat 0.5 14 days
Other cereal
grains 0.2
REFERENCE
USDA. Submission from the United States Department of Agriculture to
FAO, 22 May, 1980.
See Also:
Toxicological Abbreviations
D, 2,4- (AGP:1970/M/12/1)
D, 2,4- (WHO Pesticide Residues Series 1)
D, 2,4- (WHO Pesticide Residues Series 4)
D, 2,4- (WHO Pesticide Residues Series 5)