ENDOSULFAN JMPR 1974
Explanation
Endosulfan was previously evaluated at the Joint Meetings of
1967, 1968, and 1971 (FAO/WHO 1968, 1969, 1973). The recommendation
for a temporary tolerance of 2 mg/kg in fruit and vegetables made by
the 1968 JMPR was confirmed in 1971 and additional tolerances of 0.5
mg/kg in cottonseed and 0.2 mg/kg in crude cottonseed oil were
recommended. The tolerances were to include residues of the two
stereoisomers, endosulfan A and B, and the metabolite endosulfan
sulphate.
The 1974 Joint Meeting has been asked to consider the following
requests with respect to the recommended tolerances.
1. The Codex Committee on Pesticide Residues (CCPR) has requested
that the recommended tolerance of 2 mg/kg on the broad commodity
groups fruits and vegetables be reconsidered with a view to
establishing specific tolerances based on data requested from
member governments (Alinorm 74/24).
2. The CCPR further requested clarification of the commodity
definition for rice in the 1971 JMPR evaluation (item E [33], CX
4/40, PL 15/8).
3. A request was made that the present tolerances of 0.5 mg/kg in
cottonseed be increased to 1 mg/kg.
RESIDUES IN FOOD AND THEIR EVALUATION
NATURE OF RESIDUES
The fate of endosulfan in plants and animals has been previously
evaluated and there is no new information which would revise earlier
opinion that the residues of toxicological concern are endosulfan A,
endosulfan B, and endosulfan sulphate. Endosulfan is generally
regarded as a non-systemic insecticide and crop residues are
essentially on the surface. The residues to be regulated in cottonseed
are those that occur on the ginned seed as the article of commerce and
in the crude cottonseed oil. Data show that residues are located on
the lint and hulls of the raw cottonseed and not translocated.
Residues reported in oil are probably due to physical transfer during
the crushing operation. Trace residues are also found in meal and
fractions from the edible oil refining process. Residues in milk and
animal tissues are concentrated in the fat of these commodities.
RESIDUES RESULTING FROM GOOD AGRICULTURAL PRACTICE
1. Fruits and vegetables
Four countries responded to the request of the CCPR for residue
data to support adjustment of the present 2 mg/kg tolerance on fruits
and vegetables. Unfortunately, the residue data included analyses for
only the A and B isomers. Presumably the national tolerances in those
countries cover only those residue components whereas the recommended
JMPR tolerances include the sulphate metabolite. The ratios of the
endosulfan sulphate residues to the other components in crops are too
variable to calculate the total residue.
The 1974 JMPR recognizes the desirability of lower tolerances on
specific fruits and vegetables. The data which are available would
indicate that lower tolerances would be justifiable for certain
fruits and vegetables under the uses practiced in certain countries.
Because of the variation in national agricultural practices (dosage
rates, spray schedules and pre-harvest intervals) it is not possible
to conclude that a tolerance lower than 2 mg/kg would be adequate for
the needs of all countries. However, there is sufficient information
to permit lower tolerances on specific root crops which are known to
incur residues of a lower order. These would include carrots,
potatoes, sweet potatoes, and bulb onions for which a tolerance of 0.2
mg/kg would be appropriate.
2. Cottonseed
The data submitted to support the proposal for a 1 mg/kg
tolerance in cottonseed are apparently the data evaluated in the 1971
JMPR, which resulted in the recommendation for the present 0.5 mg/kg
tolerance. The difference in interpretation of good agricultural
practice with respect to dosages applied and the percentage of bolls
open at the time of application may account for the different
conclusions as to an appropriate tolerance. Thus, under somewhat
exaggerated conditions of usage, with respect to both dosage and
percentage of open bolls, total residues up to 1.16 mg/kg were
reported in ginned seed and 0.28 mg/kg in crude oil. The data would
indicate that under conditions of use as registered in the USA and
Australia, (a dosage maximum of 1.5 kg a.i./ha applied before bolls
open and up to 0.80 kg/hectare when up to 25% of bolls are open) a 1
mg/kg tolerance would be more appropriate. The formulations include
emulsifiable concentrates, wettable powders and dusts.
Cottonseed hulls and meal are components of animal feeds. It was
noted in the evaluation by the 1967 JMPR that animals fed endosulfan
secreted trace residues in milk and stored trace residues in meat fat.
The 1968 JMPR noted a study on the fate of endosulfan in the
processing of milk, which showed that some residues remained in
condensed, spray dried and evaporated milk. Analytical methods
suitable for determination in milk fat and meat fat at the 0.1 mg/kg
level are available. Endosulfan A, endosulfan B and endosulfan
sulphate are recovered by the official AOAC method for chlorinated
compounds (fat method). Residues were reported in cottonseed meal at
0.04 mg/kg and in hulls at 0.04 and 1.1 mg/kg. Cottonseed meal or
hulls may constitute up to 30% of various animal diets. Feeding
studies show that residues in milk fat or meat fat from this level in
the feed would not exceed the maximum limits shown in the
Recommendations.
METHODS OF RESIDUE ANALYSIS
Methods are available for the satisfactory determination of
endosulfan A, endosulfan B and endosulfan sulphate. All methods are
based on GLC with either microcoulometric, electron capture or flame
photometric detection and were discussed in detail in previous
evaluations. All three residue components are also measured by the
AOAC multiresidue method for chlorinated pesticides.
NATIONAL TOLERANCES REPORTED TO THE MEETING
Country Commodity Tolerance
(mg/kg)
Australia1 Fat of meat of cattle and sheep 0.2
Milk and milk products 0.5
(fat basis)
Fruits, grains, vegetables,
cottonseed 1.0
Canada2 Peas 0.5
Artichokes, beans, cauliflower,
celery, cucumber, eggplant, grapes,
melons, peppers, pumpkins, squash,
strawberries, tomatoes, watercress 1.0
Apples, apricots, broccoli,
Brussels sprouts, cabbage, cherries,
lettuce, nectarines, peaches, pears,
plums, prunes, spinach 2.0
New Zealand3 Fruits and vegetables 2.0
Netherlands3 Berries, mushrooms 1.0
Fruit (except berries) and
vegetables 0.5
Potatoes 0.1
South Africa2 Cabbage, green beans, boysenberries,
youngberries, tomatoes, cucurbits,
peas, citrus 2.0
Peaches, apples, pears 0.5
Country Commodity Tolerance
(mg/kg)
USA1 Apples, apricots, artichokes, beans,
broccoli, Brussels sprouts, cabbage,
cauliflower, celery, cherries,
collards, cucumbers, eggplant,
grapes, kale, lettuce, melons,
mustard greens, nectarines, peaches,
pears, peas, peppers, pineapple,
plums, prunes, pumpkins, spinach,
strawberries, summer squash, sunflower
seed, tomatoes, turnip greens,
watercress, winter squash 2.0
Alfalfa hay, almond hulls,
cottonseed 1.0
Milk fat, sugarcane 0.5
Alfalfa (fresh) 0.3
Carrots, sweet corn, sweet potatoes,
meat, fat of meat of cattle, goats,
pigs, horses, sheep 0.2
Blueberries, grain of barley, oats,
rye, wheat, sugar beets 0.1
1 Includes endosulfan A and D, and endosulfan sulphate.
2 Includes endosulfan A and B.
3 Residue not specified.
APPRAISAL
The CCPR referred to the Joint Meeting a request that the
recommended 2 mg/kg tolerances (JMPR 1971) for endosulfan residues on
fruits and vegetables be re-examined to determine whether tolerances
on specific crops at levels reflecting actual residues could be
recommended. Four countries responded to the request for data to
support the proposed changes. Essentially all of the residue data made
available included analyses for the A and B isomers but not for the
endosulfan sulphate metabolite, which is now regarded as a significant
component of endosulfan residues. The present recommended tolerance
(JMPR 1971) is expressed as total residues of endosulfan A, endosulfan
B, and endosulfan sulphate. The Joint Meeting was not able to conclude
that the data made available would generally support individual
tolerances on fruits and vegetables at levels below the present 2
mg/kg. The Meeting does, however, recognize the desirability of lower
tolerances whenever possible and in that interest can recommend a
lower tolerance on certain crops which are known to incur residues of
a low order. These include carrots, potatoes, sweet potatoes, and bulb
onions, for which a tolerance of 0.2 mg/kg would be appropriate.
Further consideration can be given to other tolerances on individual
crops as additional information on use patterns and residues in other
countries becomes available.
Tolerances of 0.5 mg/kg for total residues of endosulfan A,
endosulfan B, and endosulfan sulfate in cottonseed and 0.2 mg/kg in
crude cottonseed oil were recommended by the 1971 JMPR. No additional
data were made available to support a request to the 1974 JMPR to
increase the tolerance to 1 mg/kg in cottonseed. However, a
re-evaluation of the original data in relation to the use of the
product as presently practised in the US and Australia indicates that
a 1 mg/kg tolerance would be appropriate to cover total residues of
endosulfan A, endosulfan B, and endosulfan sulphate in ginned
cottonseed. Proportionally, a tolerance of 0.5 mg/kg would be
appropriate for crude cottonseed oil.
Feeding studies show that trace residues can be expected in the
milk of cattle fed cottonseed meal and hulls, and in the fat of meat
of animals. Practical residue limits are indicated for these
commodities.
The question referred to the Joint Meeting by the CCPR regarding
clarification of the commodity definition for rice in the tolerance
recommended by the 1971 JMPR has been considered. It was agreed that
the term "rice (unpeeled)" is inappropriate and should be changed to
"rice, in husk."
The further data requested by the 1971 JMPR were not made
available but are not pertinent to the adjustment of cottonseed
tolerances or the proposals regarding revisions of the fruit and
vegetable tolerances.
RECOMMENDATIONS
The following tolerances are for the sum of endosulfan A and B
and endosulfan sulphate, expressed as endosulfan.
TOLERANCES mg/kg
Tea (dry, manufactured) 30
Fruits 2
Vegetables (other than exceptions noted) 2
Carrots, potatoes, sweet potatoes, bulb
onions 0.2*
Cottonseed 1.0*
Cottonseed oil (crude) 0.4*
Rice, in husk 0.1*
PRACTICAL RESIDUE LIMITS
Milk and milk products (fat basis) 0.5*
Fat of meat 0.2*
* New Limit
FURTHER WORK OR INFORMATION
DESIRABLE
Additional residue studies in which total residues of endosulfan
A and B and endosulfan sulphate are measured and related to the
agricultural practices in those countries with registered uses.
REFERENCES
FAO/WHO. (1968) 1967 Evaluations of some pesticide residues in food.
FAO/PL/1967/M/11/1; WHO/Food Add./68.30.
FAO/WHO. (1969) 1968 Evaluations of some pesticide residues in food.
FAO/PL/1968/M/9/1; WHO/Food Add./69.35.
FAO/WHO. (1973) 1971 Evaluations of some pesticide residues in food.
AGP/1971/M/9/1; WHO Pesticide Residue Series, No. 1.