PESTICIDE RESIDUES IN FOOD - 1984
Sponsored jointly by FAO and WHO
EVALUATIONS 1984
The monographs
Data and recommendations of the 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, 24 September - 3 October 1984
Food and Agriculture Organization of the United Nations
Rome 1985
CAPTAN
Explanation
Captan was evaluated in 1965, 1969, 1973, 1974, 1977, 1978, 1980
and 1982 1/ at which times numerous limits were estimated or revised.
It was scheduled for toxicological evaluation in 1984 as a result of
the 1982 review. The last residue review was in 1980 at which time
limits for cherries and potatoes were revised and additional
supervised trials data and information on good agricultural practice,
especially on pre-harvest uses on potatoes, was considered desirable.
Additional information on uses, monitoring data, residue trials,
national tolerances and persistence is reviewed herein.
RESIDUES IN FOOD AND THEIR EVALUATION
USE PATTERN
Information was available on nationally approved use patterns in
four countries. Those of The Netherlands are summarized in Table 1 and
those of New Zealand, Canada and Sweden in Table 2.
RESIDUES RESULTING FROM SUPERVISED TRIALS
Information on captan residues resulting from supervised trials
was provided from three countries and the data are summarized in
Tables 3-7. Pre-harvest intervals in one country were "nil" for all
commodities, but longer in other countries. It is necessary therefore
to consider residues shortly before harvest.
Apples, pears. Supervised trials residue data were provided by one
of the countries (Canada) providing additional good agricultural
practice information. In one trial (Table 3) application rates
reflected good agricultural practice in that country, although none of
the data reflected Canada's 7-day pre-harvest interval. Maximum
residues were 3.2 mg/kg at 14 days after the last application and not
markedly different at 21-22 days except for one residue of 8.4 mg/kg.
Judging from the dissipation rate indicated, residues at the 7-day
pre-harvest interval would probably not exceed 10 mg/kg. Data reviewed
by the 1978 JMPR indicate that residues can approach or even exceed 10
mg/kg from pre-harvest use alone.
1/ See Annex 2 for FAO and WHO documentation.
Table 1. National use pattern of captan in The Netherlands
Crop and Pest Application rate Formulation Treatment Pre-harvest In use
situation controlled interval since
g/100L kg/ha (days)
Fruit:
Apple and Scab 120 2.5 wp 85% spraying at 7-10 - before
pear (Venturin sp.) day intervals 1965
until mid-June
100 2.0 wp 83% spraying at 10- - before
day intervals 1965
after mid-June
until shortly
before harvest
Scab + Fruit 120 2.5 spraying at 7-12 about
rot (Pexicula day intervals 1968
mulicortis after mid-July
until shortly
before harvest
Nectrica-Fruit 200 2.0 autumn spraying about
tree 1968
Cherry Fruit-rot 120 2.5 wp 83% spraying 14-8 4 1965
days before
harvest
Strawberry Fruit-rot 120 2.25 wp 83% weekly sDraying 4 1965
Outdoors (Botrytis sp.) from shortly before
blossoming until
4 days before harvest
Table 1. (continued)
Crop and Pest Application rate Formulation Treatment Pre-harvest In use
situation controlled interval since
g/100L kg/ha (days)
Strawberries Fruit-rot Not more than two 14 about
glasshouse (Botrytis sp.) sprayings from 1975
blossoming until
2 weeks before
first harvest
Blackberry Botrytis sp. 120 wp 83% repeated 4 before
Raspberry spraying 1965
Currants Botrytis sp. 120 wp 83% repeated 10 before
(black, red spraying 1965
and white)
Vegetables: Anthracnose 120 1.2 wp 83% repeated 21 about
Endive (Marssonina sp.) spraying until 1968
3 weeks before
harvest
Leek Phytophtora 300 3.0 wp 83% repeated spraying 21 about
with 10-12 day 1970
intervals
The wettable powder and a 10% dust are also used in floriculture and on nursery stock
Table 2. National use patterns of captan in Canada, New Zealand and Sweden
Application rate Interval, last
kg a.i./ha or application to harvest
Commodity Formulation (kg a.i./10001) (days)
CANADA
Pre-harvest
raspberry solid, susp., WP (1), multiple 2
WP 2.25 (with benomyl)
blackberry WP 1.75, multiple
WP 2.25 (with benomyl)
loganberry dust, WP 1.1-1.75, multiple 2
blueberry dust, WP 1.75, multiple 2
strawberry solid, WP 2.25-3.25 2
dust 2.5-4.25, multiple
WP 3.25 (with benomyl) 2
rhubarb (in 1-1.5, multiple 2
forcing sheds)
cucumber solid, susp. 1.75-2.5 (young plants) or 2
WP, dust 2.5-3.25 (mature plants);
multiple
pepper 5% dust Not given, multiple 2
eggplant 5% dust " " " 2
tomato (field, solid, susp., WP 1-3, multiple 2
greenhouse dust 1.75-4.25 2
Table 2. (continued)
Application rate Interval, last
kg a.i./ha or application to harvest
Commodity Formulation (kg a.i./10001) (days)
NEW ZEALAND
(Replaces 1973, 1975, 1977)
Pre-harvest 80% WP 2-4 "Nil"
or
pip fruit (0.1 - 0.15)
stone fruit
citrus
grapes
strawberries
vegetables
ornamentals
Seed treatment 60% 100-300 g a.i.
Protectants per 100 kg seed
vegetables
cereals
fodder crops
SWEDEN
Pre-harvest
fruit orchards formulation 0.05% 21
unspecified
Table 3. Captan residues on fruits resulting from supervised trials
Application Residues, mg/kg, at interval (days) after application
Crop rate
Country No. kg a.i./ha formulation 0 1 3 5 7-8 14 18 21-22 25-30 Reference
Year (g ai/100L)
Apple
Canada
1982 10 1 kg a.i. 50W 2.1 0.7 0.6 Canadian Govt.
/1001 to 2.9 0.9 1.7
run-off 0.9 1.9 0.8
0.6 1.4 0.8
3.2 3.1 2.2
1.6 8.4 1.1
1.2 1.2 1.0
1.4 0.5 2.9
Blueberry
New Zealand
1980 1 3.8 80WP 13 12.3 12 11.3 2.3 0.5 0.8 N.Z. Govt. Report
(registered) PB/7/3/3
May 1980
1979 1 3 80WP 15 11.8 6.9 6.4 3 1.4
(100)
1980 1 2 80WP 16.6 14.94 16.7 14.7 9 1.2 1.7
(100) 13 12.9 12. 10.9 5.5 1 1.4
1978 1 (120) 80WP <0.05
0.03
1979 2 (120) 80WP 1.9 1.1 0.8 0.9 <0.05
2.5 1.9 1 1 <0.05
Table 3. (continued)
Application Residues, mg/kg, at interval (days) after application
Crop rate
Country No. kg a.i./ha formulation 0 1 3 5 7-8 14 18 21-22 25-30 Reference
Year (g ai/100L)
Currants
New Zealand
1979 4 1.3-2.9 80WP 4.43 3.3 2 4 PB 7/3/3
(100-160) registered 4.3 4.0 2
(2 trials) 2.1 2
3.9 2
6 4.9-9 80WP 17.84
(120) 19.1
23.1
20.3
6 1.6-2.5 80WP 5.44
6.2
(68-120) 5.2
<0.05
1 2.2 80WP 10 6.7 6.3 4.3
(120) 5.4
1 8 5.8 3.9 3.6 0.6
(120) 1.35
Table 3. (continued)
Application Residues, mg/kg, at interval (days) after application
Crop rate
Country no. kg a.i./ha formulation 0 1 2 5 7-8 14-15 17-20 21-22 25-30 31-35 68-75 >75 Ref.
Year (g ai/100L)
Kiwi fruit
New Zealand
1980 1 2.7 80WP <0.16 <0.1 <0.1 <0.1 0 N.Z. Govt.
(80) registered report 13/5
1980 3 2.7 " 7.16 1.9 2.2 0.2 "
1979 2 1.4.1 80WP 2.7 1.2 1 1.1 <0.1 <0.1 N.Z. Govt.
1 <0.6 report
1.2 <0.7 PB 13/7/5
<0.6 0.71
<0.6
<0.6
<0.6
<0.6
2
1979 1 1.1-4.4 80WP Range 0.08- "
3 (4 trials) 0.43
Mean 0.18±
S.D. 0.13
1978-79 9-14 1.5-3.5 80WP Range 6.3- "
(100) 15
' (6 trials) Mean 9.2±
S.D. 2.5
No. of samples:
17
Table 3. (continued)
Crop Application Residues, mg/kg, at interval (days) after application
rate
Country no. kg a.i./ha formulation 0 1 2 5 7-8 14-15 17-20 21-22 25-30 31-35 90-120 Ref.
Year (g ai/100L)
Kiwi fruit
New Zealand Range 5.5- N.Z. Govt.
1978-79 9-10 1.5-3.2 80WP 13.8 Report
(100) registered Mean 9 ± PB 4 June
(4 trials) S.D. 2.5 1981
No. of samples 17
whole8
1978-79 11-15 1.3-3.5 80WP Range 4.2-7 1.7- 2.8- 2.1- 0.7- 2.2- 3.5- 0.9-
(100) 14.3 10.5 6.5 13.1 9.2 12.5 10.7 5.5
(16 trials) Mean 8.5± 5.5± 4.7± 6.2± 4.4± 6.4± 5.8± 2.4±
S.D. 3 2.9 1.5 3.3 2.5 3.5 3.1 1.2
No. of values 16 7 7 11 18 7 7 28
edible 8,9
Range <0.1-0.4
Mean 0.04±
S.D. 0.01
No. of values 24
Table 3. (continued)
1 Duplicate blueberry values represent different varieties
2 12 days
3 Each sample from each half of trial
4 Each sample from each quarter of trial
5 10 days
6 Average of duplicates
7 Range of means of individual trials at all intervals
8 Samples at 90-120 days cool-stored
9 All 90-120 day edible sample values <0.1 mg/kg except one each at 0.3 and 0.4 mg/kg
This is confirmed in other Canadian trials (Table 7: Frank et
al., 1984) where captan was applied to apples at the normal rate and
half of it. Maximum residues varied from 15.7 mg/kg at day 0 to
approximately 7 mg/kg at that country's 7-day pre-harvest interval or
at 10 days. The authors note that at least 6 mg/kg is required for
efficacy on apples and pears and suggest that a half-rate application
near harvest may be adequate. Residues were reduced by rainfall in
only two of the six trials and in some trials were relatively constant
for 7 days. The number of applications did not appear to affect
residue levels significantly. These authors also reported trials on
pears in which residues were comparable to those in some apple trials
(Table 7).
These data and those reviewed by the 1977 and 1978 JMPRS indicate
that residues may approach and occasionally exceed 10 mg/kg from
pre-harvest uses alone at intervals around 7 days and even
occasionally approach 20 mg/kg at the 0-day interval permitted in some
countries. Data reviewed by the 1977 JMPR indicate that post-harvest
uses can also result in residues of the order of 10 mg/kg. There is no
basis for lowering the current 25 mg/kg limit. This is supported by
monitoring data (see "Residues in commerce or at consumption").
Blueberries. Supervised residue trial data were available from New
Zealand (Table 3). Although it is not entirely clear what formulation
was used, it was presumably the 80 WP since that is the product
registered in that country for other fruit. No good agricultural
practice information was provided. It is not clear on what basis the
current 20 mg/kg Codex limit was estimated, although it is first
recorded in the report of the 1973 JMPR. If the data presented to this
meeting represent good agricultural practice, residues up to 17 mg/kg
on the day of last application and 15 mg/kg even at 7-8 days show that
the 20 mg/kg limit is required.
Currants. Residue trials data were available only from New Zealand
(Table 3) and good agricultural practice information from The
Netherlands. Good agricultural practice information was provided for
"pip fruit" from New Zealand. Application rates on currants were
consistent with those for pip fruit, although the approved withholding
period was only identified as "nil". The interval is 10 days in The
Netherlands, but these countries are not in close proximity, nor do
they have similar climates. Maximum residues were 23, 6 and 4 mg/kg at
3, 7-8, and 12 days respectively. Assuming the trials reflected good
agricultural practice, as they apparently did, the current 20 mg/kg
limit is supported.
Kiwi fruit. Residue data from 34 trials were provided from one
country (Table 3). Application rates generally reflected approved
rates in that country, although it is not clear how many applications
are good agricultural practice, nor what the exact approved
withholding interval is since it was only described as "nil". Numbers
of applications ranged from one to 15. Data were available for
intervals of one to 120 days from last treatment.
The maximum residue 2 days after the last application was
15 mg/kg. The highest mean residues in individual trials were
14.3 mg/kg at 2 days and 10.7 mg/kg at 31-35 days. The maximum mean
residue was 5.5 mg/kg even after 90-120 days after the last
application when stored under "cool" conditions. Most residues in the
edible portion of the 90-120 day samples were <0.1 mg/kg. The highest
was 0.4 mg/kg.
The number of applications appears to affect residue levels,
which in some trials were relatively constant from 2 days to one month
after application. Residues will, therefore, not necessarily decrease
markedly even on relatively long storage.
If the trials reflect good agricultural practice, a 20 mg/kg
limit would appear to be required with a 2-day pre-harvest interval.
Additional information on the approved number of applications and the
exact withholding interval is need for the country in which the trials
were conducted. Good agricultural practice information and residue
data from additional countries are desirable.
Cherries. The persistence of captan on cherries has been
investigated in relation to the reduction of one national tolerance to
5 mg/kg (Northover et al., 1984). The concern was whether residues
could be maintained at the 2-3 mg/kg level necessary for efficacy.
Supervised trials reflecting commercial practice are summarized for
sweet and sour cherries in Tables 4 and 5 respectively. Maximum
residues were approximately 30 mg/kg on the day of last application
and 2-4 mg/kg after 14 days in the 1983 trials, but were lower in the
1982 trials with maxima of 13 and 5 mg/kg at 0 and 14 days
respectively in sour cherries. Sweet cherry residues were generally
somewhat higher than sour at comparable intervals. The author
considered the 1983 data to be exceptionally high and suspected
analytical difficulties, but there is no firm evidence to support that
view.
These and other data from the same studies indicate that rain can
reduce residues by 50%, but show that losses can be much less. In the
absence of rain, residues decreased little during 7 days. The authors
also demonstrated that water washing can remove 50% of the residue or
substantially more, depending on its thoroughness (see "Fate of
residues in processing").
These data together with those previously reviewed by the JMPR
clearly show that the current 50 mg/kg limit is reasonable for pre-
harvest uses where harvest on the day of last application is
permitted. Additional post-harvest treatment, as permitted in some
countries, reinforces the need for such a limit. Water washing before
marketing or consumption would give reasonable assurance that residues
would be substantially below MRL levels at consumption, even if close
to them initially.
Table 4. Decline of captan residues on sweet cherry fruits remaining
on trees, in relation to cumulative rainfall, in 1982 and
1983.
Date and application rate
1982 1983
7x2.4 kg a.i.50% WP/ha 5x2.5 kg a.i.50% WP/ha
Interval, Residue Rainfall Residue Rainfall
(mg/kg) (mm) (mg/kg) (mm)
Pre-spray 2.8 -- 4.1 --
Post-spray
0 6.7 0 26.5 3
1 5.2 0 9.5 3
2 2.8 0 7.9 3
3 4.6 0 11.9 3
5 5.0 0 9.8 3
7 4.4 0 13.4 3
10 1.9 30 --
11 -- 4.5 42
14 1.8 30 4.3 55
Unsprayed 0.01 0.04
Mean temp. (14 days): 21.1°C 23.6°C
Table 5. Decline of captan residues on sour cherry fruits
remaining on trees, in relation to cumulative
rainfall, in 1982 and 1983.
Date and application rate
1982 1983
8x3.4 kg a.i.50% WP/ha 4x3.5 kg a.i.50% WP/ha
Interval, Residue Rainfall Residue Rainfall
(mg/kg) (mm) (mg/kg) (mm)
Pre-spray 10.4 -- 3.5
Post-spray
0 13.4 0 29.5 0
1 8.1 0 31.5 3
2 6.2 30 18.5 3
3 7.0 30 10.6 3
5 9.7 30 12.5 3
7 8.6 38 8.3 3
10 5.5 51 -- --
11 -- 3.0 42
14 4.8 60 2.1 55
Unsprayed 0.02 0.01
Mean temp. (14 days): 20.8°C 23.6°C
Table 6. Decline of captan residues on peach fruits remaining on trees in relation to cumulative
rainfall in 1981 and 1983.
Date, variety and application rate
1981 1983
Redhaven Garnet Beauty Redhaven
3 x 3 kg a.i. 3 x 3.4 kg a.i. 4 x 3.4 kg a.i.
50 %WP/ha 50 %WP/ha 50 %WP/ha
(Dilute) (Airblast) (Airblast)
Interval, Residue Rainfall Residue Rainfall Residue Rainfall
days (mg/kg) (mm) (mg/kg) (mm) (mg/kg) (mm)
Pre-spray 3.0 -- 1.7 -- 9.6 --
Post-spray
0 12.1 0 9.9 0 11.1 0
1 6.5 27 7.3 0 10.2 0
2 -- -- -- -- 11.7 0
3 5.8 29 -- -- 15.5 0
4 -- -- 2.7 1 -- --
5 6.6 34 -- -- 13.1 8
7 6.1 34 2.2 42 11.1 14
10 4.8 34 -- -- 8.9 14
12 -- -- 2.9 42 -- --
14 -- -- 1.7 42 2.9 24
Unsprayed 0.06 -- 0.24
Mean temp. (14 days): 19.1°C 20.7°C 23.1°C
Table 7. Captan residues in fruits resulting from supervised trials in Canada
(Frank et al., 1984; Ritcey et al., 1984)
Application Residues, mg/kg, at interval (days) after application
Crop no. rate 0 1 2 3 5 7 10 14 15 18-38
Year kg a.i./ha formulation
Apples
1982-83 3 1.7 50%WP 12 a 3.7 4.3 4.3 3.4 3 1.9 c
15 4.2 3.3 4.7 5.4 3.9 3.2 4.2
3 3.4 15.7 8.5 5.1 7.3 3.9 3.2
7 5.3 3.9 4.4 3.8 4.7 3.3 4.4
7 5.1 2.8 2.6 3 3.5 2.3 2.2
12 9.4 4.2 4.1 9.4 6.9 7.1 5.1
Pears
1983 3 3.4 50%WP 7.8 5.5 4.7 5.9 3.8 2.1 1.7
1982 4 3.5 3.7 2.2 1.1 2.3 1.1 1.2
Grapes
1981 1 2.8 50%WP 3.3 4.5 3.1 2.5 3.4 4.6 3.5
1982 1 1.7 1.5 2.7 2.1 2.1 2.1 0.6
1981 5 8.3 7.3 4.9 4.1 3.4 2.4 d
2.9 e
Strawberries
1982
Berries b 1 3.4 80%WP 2.4 1.8 0.9 1.3 0.93 0.31
Foliage 17 24 19 21 17 1
Strawberries
1983
Berries b 3.4 80%WP 4.1 4.1 3 0.91 0.8 0.26
Foliage 28 23 21 15 19 8.7
Calyz 4.2 2.5 7.1 5 3 1.9
Mulch straw 97 51 30 45 3.5 21
Table 7. (continued)
a Apples small (80-100g) in this trial
b Residues are the mean of 4 replicates
c 18 days
d 21 days
e 38 days
Table 8. Residues found in monitoring in The Netherlands, 1981-1983
Commodity Range (mg/kg) No. in range Total no. Codex MRL, mg/kg
apple 10-15 2 530 25
currants 15-20 4 159 20
endive 3- 5 1 12 15
10-15 0
grape 10-15 1 42 none
5-10 6
pear 15-20 1 132 25
raspberry 15-20 2 66 10
10-15 7
5-10 12
strawberry 45-54 4 368 20
15-20 1
10-15 14
tomato 10-15 2 6 15
Peaches. Supervised trials with captan on peaches were also
available (Northover et al., 1984) and are summarized in Table 6.
Applications were said to reflect commercial practice. Maximum
residues in the 1983 trial were 15.5 mg/kg 3 days after the last
application, with little dissipation during the first 10 days. In the
1981 studies residues decreased to about one third of the initial
deposits in 10-12 days. In contrast to cherries, residues in peaches
were not substantially affected by rainfall except shortly after
application. Thorough washing removed only a maximum of 50% of the
initial deposits as contrasted to cherries where very thorough washing
could remove most of the residue (see "Fate of residues in
processing"). The data support the Codex limit of 15 mg/kg even for
the 2-day pre-harvest interval of the country where the trials were
conducted.
Grapes. Supervised trials were conducted in Canada (Frank et
al., 1984). Data are summarized in Table 7. The rates apparently
reflect good agricultural practice in that country, although the kg
a.i./ha rates cannot be equated with kg a.i./1000 l of Table 2.
Maximum residues ranged from 8.3 mg/kg at day 0 to 4.1 mg/kg at
Canada's 7-day pre-harvest interval. In two of the trials residues
were relatively constant from 0 to 10 days. Rainfall affected residue
levels in two of the three trials. These data indicate that residues
would probably not exceed 5 mg/kg from Canadian good agricultural
practice. Additional data and good agricultural practice information
are needed to support a limit.
Strawberries. Data were available from one country (Ritcey et
al., 1984) and are summarized in Table 7. Applications reflect good
agricultural practice in the country where the trials were conducted
and where the pre-harvest interval is 2 days. The interval ranges from
"nil" to 4 days in other countries for which information was provided.
Maximum residues on berries were 4.1 mg/kg on the day of treatment and
3 mg/kg after two days. Residues were much higher on the foliage and
straw and comparable on the calyx. Rainfall did not appear to reduce
residues substantially. This was confirmed with simple water rinses
(See "Fate of residues").
The current 20 mg/kg limit is more than adequate to accommodate
Canadian good agricultural practice with single applications, even on
the last day of application. Data reviewed by the 1978 JMPR clearly
show that even average residues from glasshouse use (two applications)
can reach 20 mg/kg and information provided to this meeting confirms
that use, so there is no basis for lowering the current limit. This is
supported by monitoring data (see "Residues in commerce or at
consumption").
The question has been raised as to why the limit for cherries
(50 mg/kg) is higher than that for strawberries. No definite
explanation can be given. Higher residues would be expected on
strawberries with similar use patterns, in view of the surface area to
weight ratios. In both cases rainfall can reduce residues
substantially, although in some trials with cherries it did not.
Foliage protection may differ between the two. It is more likely that
uniform residue deposition and representative sampling are more
difficult with cherries, since it has been shown (Northover et
al., 1984) that residue levels are higher in the lower outside areas
of cherry trees.
It is also noted that residues on strawberries and raspberries
moving in commerce (see below) sometimes exceed the limits for those
commodities, which suggests that their MRLs may be too low.
FATE OF RESIDUES
In storage and processing
Some information on the fate of residues in storage or processing
was available on several commodities. It has already been noted above
that rainfall can reduce captan residues on apples, but not
consistently.
In cherries (Northover et al., 1984) water rinsing for 15 and
120 seconds removed 70 and 97% respectively of field-incurred
residues, although it is not clear whether sampling was immediately
after application or after several days. Storage at 4° or 20°C for two
weeks resulted in no loss of residue.
The same authors reported on residue losses in peaches. As noted
above, rainfall did not substantially reduce captan residues on
peaches. Similarly, 10-second "hand washing" remove a maximum of 50%
of the initial residue, whereas simple rinses removed substantially
more from cherries. Even vigorous washing with a stiff bristle brush
removed only 70% from peaches.
Residues were also determined in the products of grapes processed
into wine (Frank et al., 1984). With initial deposits on grapes of
2.2 mg/kg 8 days after treatment, residues were 1.9 mg/kg on
de-stemmed grapes, 16 mg/kg on stems, and <0.01 mg/kg in fermented
juice and wine.
For strawberries, several post-harvest treatments have been shown
to remove residues from initial deposits of 2.4 mg/kg: a 20-minute
cool water rinse removed 14%; calyx removal gave 36% reduction; calyx
removal followed by warm and cool water rinses, 63% and calyx removal
followed by a 5 minute cook, 95%. No losses were reported on storage
at -20°C for 3 months (Ritcey et al., 1984).
EVIDENCE OF RESIDUES IN FOOD IN COMMERCE OR AT CONSUMPTION
Substantial data were provided to the meeting on residues in
commerce. In U.K. monitoring in 1981-1984, residues in apples and
pears were well below the 25 mg/kg Codex (maximum of 0.9 mg/kg on
imported apples), and one positive result (0.2 mg/kg) was found in 30
grape samples. Residues found in Swedish monitoring of domestic and
imported cherries and potatoes in 1981-1983 were <1.01 mg/kg. In 1983
Canadian monitoring of domestically grown cherries, residues were
<0.78 mg/kg in 19 samples taken at the packing plant.
Substantial monitoring data were provided from The Netherlands on
a wide range of commodities with and without Codex MRLs. 1981-1983
data on domestic and imported commodities for which there are Codex
MRLs and on which residues were found near or above Codex limits are
given in Table 8.
Seed Treatments
Substantial information on Canadian captan seed treatments was
also provided on many fruits, vegetables and field crops with
emulsion, WP and suspension formulations, either alone or with other
presticides. It was not possible to includes these in this summary.
Application rates are typically 50-200 g a.i./100 kg seed.
In general, monitoring data provided to the meeting give
reassuraance that current limits are adequate. The Netherlands' data
suggest that limits for respberries and strawberries may not be high
enough if the residues in fact resulted from good agricultural
practice. Residues on blackberries (for which there is no Codex MRL)
also exceeded 20 mg/kg.
NATIONAL MAXIMUM RESIDUE LIMITS
National MRLs were reported for four countries:
Country Commodity MRL, mg/kg
The Netherlands apricots 20
currants (black,red,white) 20
strawberry 20
tree nuts 15
other fruit 15
spinach 20
other vegetables 15
cereal grains 0.1*
other foods 0* (0.1)
*At or about the limit of determination
New Zealand fruit 10
vegetables 10
Poland fruit and vegetables 6
Canada plums, strawberries,
raspberries, peach,
pear, tomato, apricot,
apple, grape, cranberry,
cherry, blueberry 5
APPRAISAL
The meeting considered additional information on agricultural
practices, and residue data from supervised trials, monitoring,
processing and storage. Current limits were confirmed for pome fruit,
blueberries, currants, cherries, peaches and strawberries. Data or
other information were insufficient to estimate limits for grapes.
Substantial data were available for Kiwi fruit from one country.
Rainfall had varying effects on residue levels, depending on the
commodity, ranging from substantial in some trials on cherries to
minimal to moderate for strawberries and peaches. In trials on several
commodities residues were slow to dissipate in the absence of rain.
Washing was shown to remove over 50% of the residue on some
commodities and less on others. No losses were evident under cold
storage. Kiwi fruit residues were slower to dissipate when storage was
under cool conditions. Residues did not concentrate in grape juice or
wine.
Monitoring data provided reassurance that current captan limits
on many commodities are adequate, although residues on strawberries
and raspberries suggest good agricultural practice may not have been
followed or that the limits might be too low.
The meeting considered the question of the MRL for cherries being
higher than that for strawberries and concluded that data based on
good agricultural practice supported current limits. The most likely
reason for substantial differences in the maximum residue is uneven
deposition of captan and/or the greater difficulty of representative
sampling of cherries, although other factors could contribute to the
difference.
Questions have also been raised on the definition of the residue.
In the absence of additional information on the fate of residues, the
meeting concluded that the current definition, which specified captan
only, should be retained.
The meeting examined residue data from supervised trials
reflecting good agricultural practice on a number of crops and was
able to estimate the maximum residue levels which are likely to occur
when captan is used in practice and when the reported intervals
between last application and harvest are observed. These levels refer
only to the parent compound.
RECOMMENDATIONS
Pre-harvest interval on which
Commodity MRL (mg/kg) recommendation is based (days)
Kiwi fruit 20 2
FURTHER WORK OR INFORMATION
Desirable
Additional information on the number of applications and
pre-harvest intervals for Kiwi fruit from the country from which
data were provided and additional data and information on good
agricultural practice for captan on Kiwi fruit from additional
countries.
REFERENCES
Northover, J., Frank R., and Braun, H.E. Persistence of Captan on
1984 Cherry and Peach Fruits. Unpublished document provided by
the Canadian Government. Proposed for publication in Agric.
Food Chem. 1984. Contact: Mrs. Jean Stalker, Room 1129, K.W.
Neatby Bldg., C.E.F. Agriculture Canada, Carling Ave.,
Ottawa, Ontario, K1A 0C6.
Frank, R., Northover, J. and Braun, H.E. Persistence of Captan on
1984 Ontario-grown Apples, Grapes and Pears. Unpublished document
made available by the Canadian Government. To be submitted
to Agric. Food Chem. Contact: Mrs. Jean Stalker.
Ritcey, G., Frank, R., McEven, F.L., and Braun, H.E., Captan Residues
1984 on Strawberries and Estimates of Exposure to Pickers.
Unpublished document provided by the Canadian Government.
Sent to: Archives of Environmental Contamination and
Toxicology. Contact: Mrs. Jean Stalker.
See Also:
Toxicological Abbreviations
Captan (HSG 50, 1990)
Captan (ICSC)
Captan (PIM 098)
Captan (FAO/PL:1969/M/17/1)
Captan (WHO Pesticide Residues Series 3)
Captan (WHO Pesticide Residues Series 4)
Captan (Pesticide residues in food: 1977 evaluations)
Captan (Pesticide residues in food: 1978 evaluations)
Captan (Pesticide residues in food: 1980 evaluations)
Captan (Pesticide residues in food: 1982 evaluations)
Captan (Pesticide residues in food: 1984 evaluations)
Captan (Pesticide residues in food: 1990 evaluations Toxicology)
Captan (Pesticide residues in food: 1995 evaluations Part II Toxicological & Environmental)
Captan (IARC Summary & Evaluation, Volume 30, 1983)