PESTICIDE RESIDUES IN FOOD - 1979
Sponsored jointly by FAO and WHO
EVALUATIONS 1979
Joint meeting of the
FAO Panel of Experts on Pesticide Residues
in Food and the Environment
and the
WHO Expert Group on Pesticide Residues
Geneva, 3-12 December 1979
PROPARGITE
Explanation
The 11th Session of the CCPR noted that the 1978 Meeting had reduced
the temporary MRL on apples and pears from 3 mg/kg to 2 mg/kg. The
U.S.A. delegation promised to make data available to support a higher
limit. This addendum is an assessment of the data provided.
USE PATTERN: Pre-harvest (USA)
Pre-harvest
Dose rate No. of Interval
Crop lb. a.i./A applications PHI Days
Apples 1.3-3.6 (WP) 3 7
1.25-3.75 (EC) 3 7
Pears 0.90-2.25 (WP) 2 14
RESIDUES FROM SUPERVISED TRIALS
Residue data for propargite on apples were made available from the
United States, some of which may have been examined previously. There
are two sets of data. The first (1) gives residues at a 7-day PHI
which reflects U.S. agricultural practices. Those data which most
nearly reflect the U.S. dosage rate are summarized in Table 1 for both
a wettable powder formulation and an emulsifiable concentrate. They
have also been adjusted in the last column to the maximum U.S. dosage.
The adjusted values for the 57E give a strong indication that residues
can be on the order of 3 mg/kg from U.S. agricultural practices.
The second set of data (2) are less useful in that they are at one day
instead of 7 days. These are tabulated in Table 2 by the range of 5
replicate analyses from each of five states. The mean value given is
the mean of the five replicates adjusted to 7 days assuming a
half-life of 6 days. This is a reasonable estimate of a half-life on
apples which is suggested by data in the 1977 Evaluations. Data in
the 1978 Evaluations indicate that the disappearance is actually
minimal within 7 days. Again, these mean values indicate that
residues could reasonably be expected to exceed 2 mg/kg at 7 days.
This is even more strongly indicated if the mean values are adjusted
to maximum U.S. dosage. These values are given in the last column of
Table 2 and actually indicate that residues could approach 4 mg/kg at
7 days.
Table 1. Propargite - Apples
Formulation
30 W (Wettable powder) 57E (Emulsifiable concentrate)
residue adjusted lb.a.i./A residue adjusted
lb.a.i./A mg/kg residue mg/kg residue
4.8 1.6 1.2 4.4 - -
4.8 - - 4.4 2.1 1.8
3.0 1.6 1.9 2.3 2.4 3.3
2.4 0.8 1.2 2.2 1.7 2.9
2.4 0.9 1.3 2.2 1.5 2.5
2.4 0.5 0.75 2.2 0.5 0.85
Table 2. Propargite - Apples
Formulation
30 W 57E
lb.a.i. Residue Mean lb.a.i. Residue
per Acre range Meanb adj.c per Acre range Meanb Mean
mg/kga mg/kga adj.c
Vermont 2.1 2.1-3.3 1.3 2.2 2.2 3.2-6.5 2.5 4.3
Pennsylvania 2.4 2.2-6.3 1.9 2.8 2.5 2.2-4.5 1.6 2.4
Indiana 2.4 0.4-1.5 0.36 0.54 2.5 0.6-1.9 0.51 0.77
California 3 3-4.6 1.9 2.3 3.1 2.9-4.8 1.8 2.1
Oregon 3 1.9-2.4 1.1 1.3 3.1 3.8-5 2.1 3.5
Pennsylvaniad 1.5
Vermontd 2.3 4.0
a Residue range at one day from given dosage;
b Mean of 5 replicates for each state adjusted to 7 days assuming a 6-day half-life;
c Mean of b adjusted to maximum U.S. dosage;
d Data if high residue value is omitted.
APPRAISAL
Additional residue data from the use of propargite on apples was
received from the U.S.A. although some of this data may have been
examined in 1977. One set of data from the use of an emulsifiable
concentrate indicate that residues can be at or slightly above 2 mg/kg
from dosages less than permitted at the pre-harvest interval of 7
days. When adjusted to maximum U.S. dosage rates, residues around 3
mg/kg are indicated. Other data, adjusted to U.S. usage suggest
maximum residues around 4 mg/kg at 7 days.
The discrepancy between conclusions in the 1977 Evaluations which
recommended a temporary MRL of 3 mg/kg for apples and pears and the 2
mg/kg recommended by the 1978 Evaluations and further the
inconsistency with the interpretation of data available at this
meeting, is not entirely clear. However, the dosage rate appears a
key factor.
The 3 mg/kg recommended in 1977 was based on 0.03-0.06% application
rates. Even here a maximum value of 2.4 mg/kg is given at 14 days as
well as a 6.3 mg/kg value at 0-1 day. It is recognized that there
were many samples analyzed. The basis for lowering the temporary MRL
to 2 mg/kg by the 1978 Evaluations apparently is the additional data
submitted which did show residues just under 1 mg/kg around 7 days
after treatment. However, the monograph does not indicate the dosage
on some of the studies and for those where it is given, it is about
1/8 of that permitted in the U.S.
It is also noteworthy that recommendations for other tree fruits at 7
mg/kg from similar dosages as recommended for apples, even though
these limits are based on a 14-day pre-harvest interval. On the basis
of the information before the meeting, it appeared that good
agricultural practices in the U.S. can result in residues exceeding 2
mg/kg possibly approaching 4 mg/kg.
RECOMMENDATIONS
It is recommended that the temporary MRL on apples and pears be
revised as follows:
Commodity Limit (mg/kg)
Apples, pears 5
FURTHER WORK OR INFORMATION
Required:
The carcinogenicity study required by the 1977 Meeting.
Desirable:
The first two items listed by the 1977 Meeting and the items listed by
the 1978 Meeting.
REFERENCES
(1) Data from Section D of US petition No. 569 as made available by
Uniroyal Chemical, Division of Uniroyal, Inc., Agricultural Chemicals
Research and Development, 74 Amity Road, Bethany, Connecticut 06525,
October 9, 1979.
(2) Data from Section D of US petition No. 730 as made available by
Uniroyal Chemical, Division of Uniroyal, Inc., Agricultural Chemical
Research and Development, 74 Amity Road, Bethany, Connecticut 06525,
October 9, 1979.
See Also:
Toxicological Abbreviations
Propargite (Pesticide residues in food: 1977 evaluations)
Propargite (Pesticide residues in food: 1978 evaluations)
Propargite (Pesticide residues in food: 1980 evaluations)
Propargite (Pesticide residues in food: 1982 evaluations)
Propargite (JMPR Evaluations 1999 Part II Toxicological)