PESTICIDE RESIDUES IN FOOD - 1979
Sponsored jointly by FAO and WHO
Joint meeting of the
FAO Panel of Experts on Pesticide Residues
in Food and the Environment
WHO Expert Group on Pesticide Residues
Geneva, 3-12 December 1979
This compound was previously evaluated in 1975, in 1977 and in 1978.
The 1979 CCPR requested the meeting to review three separate matters
relating to previously recommended MRLs.
1. That the MRLs for edible offal, meat, milk and milkproducts be
converted to ERLs.
2. That different MRLs be proposed for liver and kidney instead of
the single level of 2 mg/kg recommended for kidney and liver of
cattle, goats, pigs and sheep.
3. That the recommended levels on milk and milk products be
re-evaluated to reconcile the differences between the US and the CCPR
limits bearing in mind that both are based on the same US data.
Review (in respective order)
1. The current interpretation of the definitions of MRL and ERL
(Report Meeting 1975) justify the continued use of MRL limits of
sec-butylamine since the residues of sec-butylamine in feedstuffs are
controllable by agricultural practices.
2. The data on liver and kidney are contained in reports of
twostudies (Eli Lilley 1967) and (Peoples, 1968). The test animals in
the first experiment were dairy cattle fed graduated levels of 100,
20, 5 and 2 ppm. In the second experiment cows were fed citrus pulp
from treated oranges at a rate equivalent to 16 ppm in the total diet.
There are adequate data to show that different MRL levels would be
appropriate for liver and kidney as suggested by CCPR. However, the
specific levels require a re-evaluation of the results of the two
studies in relation to a dietary intake adjusted for the proportion of
dried citrus pulp and molasses in the animal diets.
Based on data in the 1975 Meeting, maximum residues in oranges and
grapefruit would approximate 20 mg/kg. Data indicate a 3-fold
concentration in processing the fresh fruit to dried citrus pulp and
molasses, which would yield a maximum of 60 ppm in pulp and molasses.
Since the pulp and molasses normally comprise about 30% of the total
cattle diet, this would be equivalent to 18 ppm in the total diet.
This approximates the level of 16 ppm fed in the Peoples (1968)
experiment which showed a range of 0.56 to 2.7 mg/kg in kidney and
0.15 to 0.20 mg/kg in liver. The other study (Eli Lilley, 1967)
requires interpolation between the 10 ppm and 100 ppm feeding levels
which yields approximately 0.32 in kidney and 0.15 in liver. Despite
the somewhat different results in the two studies, it was concluded
that an MRL of 3 mg/kg would be appropriate for kidney and 0.2 ppm for
3. Based on the two experiments discussed above, and using the same
adjusted dietary intake from citrus pulp and molasses, the data show
that an MRL of 1.0 mg/kg would be required to cover sec-butylamine
residues occurring in milk, including endogenous sec-butylamine. The
most pertinent study, from the stand point of approximating the
anticipated dietary exposure, was Peoples, 1968. In that experiment,
5 analyses (maximum 0.67 mg/kg) exceeded the present CCPR MRL of 0.5
mg/kg and nine other figures approximated 0.5 mg/kg.
It is sometimes a practice to recommend MRLs for milk based on average
residue values because of the mixing that occurs in commercial dairy
operations. The mean value from all milk samples was 0.5 mg/kg.
However, because endogenous sec-butyalmine in milk will vary and
cannot be distinguished from the sec-butylamine added through the
pesticidal use, the meeting concluded that a MRL of 1 mg/kg would be
Sec-Butyalmine is not lipophilic and would not be expected to
concentrate in high fat dairy products. No residue analyses were
available on milk products. The previous (1977) recommendation for a
MRL on milk and milk products was based on terminology in use at that
time. It was concluded that the MRL for milk products was unnecessary
and should be deleted.
1. That the present MRLs not be converted to ERLs
2. That the present MRL of 2 mg/kg for kidney and liver be deleted
and replaced by an MRL of 3 mg/kg for kidney and 0.2 mg/kg for liver
3. That the present MRL for milk be increased to 1.0 mg/kg and
4. That the MRL for milk products be deleted.
Eli Lilly. Submission to 1975 JMPR, VPR-107-741 (1967).
Peoples. Report from School of Veterinary Medicine, Univ. Calif.