^22/380
CAFmN: POSITION EOCIWEMT 1
OFFICE OF PESTICIDE PROGRAMS
OFFICE OF PESTICIDES AND TOXIC SIBSTANCES
U.S. ENVIHCNMEifr&L PROTECTION AGENCY
EPA/SPR2> -S>o//oy
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50277^10J
documentation !3* report N0-
r"AGE - - - L EPA/SPRD-80/104
4. Title and Subtitle
Captan: Position Document 1
7. Author (s)
9. Performing Organization Namfi '.nd Address
Special Pesticide Review Division
ENvironmental Protection Agency
Crystal Mall #2
Arlington, VA 22202
12. Sponsoring Organization Name and Address
Environmental Protection Agency
401 M ST. S.W.
WAshington, D.C. 20460
15. Supple- ."nonMry Notes
1C. Abstract (Limit: 200 wordb)
3. Recipient's Accession No.
PB83 10 94 4 9
5. Report Date
__.7/22/80_
6.
3. Performing Organization RepL No.
10. Projact/Task/V/ork Unit No.
i 13. Contract(C) or Grant(G) No.
I (C)
(O)
13. Typa of Report & Period Covered
14.
Preliminary Risk Assessment: Examination of possible unreasonable
risks associated with uses of pesticide and a gathering of all available
information to determine whether or not this or any other risk does
exist. Initiates literature search and evaluates risk data. Limited
information on proposed Agency action.
j .17. Oocumcni Analysis a. Descriptors
! 0504,0606,0703
b. identifiors/Open-EncJed Tyrms
c. COSAT; Field/Group
in. Availability Statomenl
Unlimited
| IS. Security Class (This Report)
|. .Unciassifi.ed
j 20. Security Clato (Thi* Psgo)
1. I.lnr.1 as-slf,ifid
1 21. No. c! Pages
22. Price
(Set ANSI-239.18}
Sc© instructions on /Inverse
OPTIONAL FORM 272 (4-77)
(Formerly NTIS-35)
Departmont of Commerce
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T
CAPTAN
POSITION DOCUMENT 1
I. BACKGROUND 3
A. Chemical and Physical Characteristics 3
B. Registered Uses 3
1. General 3
2. tolerances 4
3. Production 5
4. Ufeage Data 5
II. REGULATORY HISTORY 11
A. USDA Actions U
B. Other Agency Reviews and Findings 12
C. Other Regulatory Actions 12
III. SIWMARY OF SCIENTIFIC EVIDENCE TO SUPPORT REBUTTABI£ PRESUMPTION 14
A. Oncogenicity 14
B. Mutagenicity 16
1. Gene Mutations 16
a. Bacteria 20
b. Bacteria with Metabolic Activation 21
c. Host-and-Fluid Mediated Bacterial Systems 22
d. Eukaryotic Microorganisms 23
e. Manmalian Cells in Culture 23
2. DNA Damage 23
a. Bacteria 25
b. Eukaryotic Microorganisms 25
c. Manmalian Cells in Culture 25
1
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3. Chromosomal Aberrations 26
a. Manmalian Cells in Culture 26
b. Dominant Lethal Tests 28
c. Heritable Translocation Test 30
C. Potential for Human Exposure 31
1. Introduction 31
2. General Population 31
a. Dietary 31
b. Nondietary (Dermal & Inhalation) 31
3. Workers 34
a. Agricultural 34
(1) Applicators, Mixers, Loaders and Bystanders 34
a) Commercial 34
b) Home Gardeners 35
(2) Harvesters -35
b. Nonagricultural 35
IV. OTHER RELEVANT ADVERSE EFFECTS 36
2
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CAPTAN
POSITION DOCLMEOT 1
I. BACKGROUND
A. Chemical and Physical Characteristics
Captan is the accepted ccmmon name for N-trichloronethylthio-4-
cyclohexene-l,2-dicarboximide. Hie chemical is also known by the
trade names Merpan, Orthocide, Vondcaptan, Vancide-89 and SR-406.
It is in the pesticide classification known as dicarboximides. The
pesticide acts as a protectant against fungal infestations, and is
used extensively as a fungicide on many food crops and plant seeds. It
is also used in several nonagricultural applications.
Physically, captan in pure form is anQodorless, white, crystalline
substance with a melting point of 178 C. The technical grade
material is a pungent, yellow to buff, amorphous powder with a melting
point of 160 C to 170 C. Its specific gravity is 1.62 as technical
grade product and 1..73 in its pure_|orm. The pyre substance has a
vapor pressure of less than 1 x 10~ nm Hg at 25 C. It is
moderately soluble in many organic solvents including chloroform,
benzene and dioxane but practically insoluble (i.e., <0.5 ppn) in
water at rocm temperature. The molecular weight is 300.57 and
the empirical formula is CqHqCUNO^S. Its structural
Captan was first patented in 1951 by the Standard Oil Development
Company (Patent Number 2,553,771). The company again patented
the chemical in 1953 (Patent Number 2,653,155). In 1955 Esso was
also issued a patent (2,713,058).
There are approximately 600 federally-registered pesticide
products containing captan as an active ingredient. These
registrations are held by 139 registrants. No federally
formula is:
B. Registered Uses
1. General
3
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registered products contain captan as an inert ingredient. There
are approximately 100 applications pending for federal registra-
tion of state-registered products containing captan as an active
ingredient.— In accordance with Section 24(c) of the
Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), 33
additional captan products have been registered in states that
have demonstrated that those products are necessary to meet
special local needs.
Captan is used as a fungicide: 1) on a wide variety of
fruit, vegetable and ornamental crops, same of which are grown on
home and garden sites; 2) on nunerous plant seeds; 3) on food
crop packing boxes; 4) in soil preplanting treatment; 5) on
surfaces inside and outside the home; 6) in cosmetics and
pharmaceuticals, oil based paints, lacquers, paper, wallpaper
paste, plasticizers, polyethylene, vinyl, rubber stabilizer and
textiles; 7) in combination with insecticides on food crops, seed
treatment and household pets. Pesticide products containing
captan are most widely used as wettable powders (50-30% captan)
and dusts (7.5-15$ captan). Other formulations are commercially
available including H-pound per gallon aqueous suspensions and
coated granules.
2. Tolerances
EPA has established tolerances, for captan residues (40 CFR
180.103) in or on these raw agricultural conmodities:
a. Tolerances for Preharvest, Postharvest or Combination Uses:
1) 100 ppm (parts per million) - beet greens, cherries,
lettuce, spinach;
2) 50 ppm - apricots, celery, grapes, leeks, mangoes,
nectarines, green onions, peaches, pluns (fresh
prunes), shallots;
17 Pesticide products formerly registered under state pesticide
registration laws and shipped or distributed for sale solely
within intrastate commerce are subject to federal pesticide
regulations under FIFRA section 3(a) and 40 CFR Section
162.17(a). Many registrants who had state-registered products
have established the intent to obtain federal registration for
intrastate use of these products.
4
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3) 25 ppm - apples, avocados, blackberries, blueberries
(huckleberries), cantaloupes, crabapples, cran-
berries, cucumber, dewberries, eggplants, garlic,
honeydew melons, muskmelons, dry bulb onions, pears,
peppers, pimentos, pumpkins, quinces, raspberries,
rhubarb, strawberries, sunnier squash, tomatoes,
watermelons, wintersquash;
4) 2 ppm - beet roots, broccoli, brussels sprouts,
cabbage, carrots, cauliflower, collards, cottonseed,
kale, mustard greens, peas, rutabaga roots, soybeans,
sweet corn, turnip greens and roots;
5) 0.25 ppm - taro
b. Tolerances for the transmission of captan residues to
meat, milk, and eggs frcm feeding cattle or poultry
with the following captan-treated commodities or their
byproducts are:
1) 100 ppm - almond hulls;
2) 25 ppm - beans, grapefruit, lemons, limes,
oranges, pineapple, potatoes, tangerines;
3) 2 ppm - almonds
3. Production
Section 7(c) of FIFRA requires manufacturers and formulators to
submit information to EPA on the production, sale, and
distribution of pesticide products. This information is
confidential and may not be made available to the public under
Sections 7(d) and 10 of FIFRA. However, a confidential memoran-
dum summarizing this information (Williams, 1980) has been sent
to the Deputy Assistant Administrator for Pesticide Programs.
4. Usage Data
The agricultural usage data as presented in Table 1 indicate
that between 8.5 and 9.7 million pounds of captan were used
annually during 1978 and 1979. The nonagricultural (industrial)
usage data estimated by the Agency are indicated in Table 2.
5
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Table 1
PRELIM INARY QUANTITATIVE USAGE OP CAPTAN IN THIS UNITED STATES
AGRICULTURE
{1978 - 1979|
Crop
Site-'
1/
Application
Unite .Treated/
year-
Application Rate/
Treatment""
(pounds a. I,)
Treatments/
Year-7
Quantity*.!./
Applled—•
(in thousands
of pounds)
Percent Crop or
Site Treated/
Year-
Pome Fruits
Apples
Pears
Peaches/
Nectarines
Apricota
Plums/
Prunes
foliage & fruit
foliage t> fruit
Stone Fruits
Cherries foliage & fruit
foliage & fruit
foliage fc fruit
Other Fruits and Nuts
Almonds foliage 6 fruit
Grapes
Lemons/
Limes
foliage & fruit
skirt treatment
165,000 - 168,000
acres
1,900 - 5, 500
acres
6,400 - 17,200
acres
73,000 - 84,000
acres
10,000 - 26,000
acres
129,000 - 154,000
acres
207,000 - 216,000
acres
7,000 - 9,000
acres
Strawberries foliage & fruit 35,000 - 39,000
2-4/Acre
3/acre
3/acre
3/acre
3/acre
4/acre
1« 5/acre
14/acre
2/acre
4-6
*-1
1-2
2,475 - 2,520 31.7 - 32.3
2-1
20 - 58
58 - 155
657 - 756
60 - 156
774 - 924
621 - 648
98 - 126
210 - 234
1.9 - 5.5
5.1 - 13.8
18.2 - 21.0
6.7 - 17.3
35.8 - 42.8
29.6 - 30.9
7.1-9.1
97.2 - 100.0
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Table 1 (Continued)
PRELIMINARY QUANTITATIVE USAGE OF CAPTAN IN THE UNITED STATES
AGRICULTURE
H978 " *979)
Crop
Site
1/
Application
Unita Treated/
Year-
Application Rate/
Treatment""
(pounds a,}«)
Treatments/
Year-7
Quantity a.i./
Appl ied-"-
(in thousands
of pounds)
Percent Crop or
Si te-Treated/
Year-*
Seed Treatments
Corn (field)
Corn (sweet)
All Other
Field Crops
All Other
Ve9etables
seed treatment 1.95 - 1.97 billion
lbs. seed
seed treatment 9.2 million lbs.
seed
.875 - .938 oz. a.}./ 1
100 lb. seed
.175 - 0.2 oz. a.i./ )
J00 lb. seed
seed treatment 273.6 - 276.0 million 2 oz. a.i./ 100 lb* seed |
lbs. seed (plants
10.5 - 10.6 million
acres)
seed treatment 569,000 - 810,000
acres
seed treatment
seed treatment
2/
2/
1.37/acre
V
1/
1
V
7/
1,102 - 1, 114
1 - 1.2
342 - 345
807 - 110
690 - 725
286 - 330
100% of seed and
planted acres
100% of seed and
planted acres
80.Q - 80.8% of seed
and planted acres
48.3 - 66.4%
v
v
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Table 1 (Continued)
PRELIMINARY QUANTITATIVE USAGE OF CAPTAN IN THE UNITEQ STATES
AGRICULTURE
(1978 - 1979)
Crop
Site
1/
Unitg^Treated/
Application Year*
Applicati^n Rate/
Treatment"
(pounds a.i.)
Treatments/ Quantity a.i./ Percent Crop or
Year* Applied* Site^reated/
( in thousands
of pounds)
Year—
Vegetables
Lettuce
Tomatoes
foliage
foliage & fruit
Other foliage t fruit
Vegetables
Commercial TJ
Greenhouses and
Ornajuentalti
All Other T_/
Agricultural Uses
(including post-
harvest)
13,000 - 53,000
acres
7,000 - 17,000
acres
7/
V
7/
). 5/acre
3/acre
7/
7/
y
7/
V
V
20 - 80
42 - 102
3b - 84
45 - 50
45 - 50
20.7 - 84.5
29.3 - 71.1
V
7/
V
Home and Garden
7/
2/
V
7/
|06 - 160
1/
Total
8,494 - 9,728
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Table 1 (Continued)
PRELIMINARY QUANTITATIVB USAGE OF CAPTAN IN TUB UNITED STATES
agriculture
(197a - 19791
J/ The crops/sites presented are those for which usage data are readily available* Al}. fruit, nut and vegetable data are for preharvest use.
2/ Units treated represent annual averages based on available data, flanges are given for those cases where usage figures are most variable.
All units can be expected to vary considerably by year due to changes in incidence and severity of disease problems. Usage estimates may
change once detailed crop/site data are gathered and analyses completed.
3/ Rates are average values based on one or more of the following) registration data, product labels/ usage data, state recommendations.
4/ Number of applications based primarily on usage data indicating incidence of retreatment.
5/ Estimates derived based on application rates, units treated and number of treatments.
6/ Estimates based on units treated per year and acres grown or estimated quantities of seed (corn, cotton) required to plant acres grown.
Estimates can be expected to change once detailed crop/site analyses are completed.
7/ Available data can not be reliably broken into more specific site estimates.
6/ See Table 4.
Sourcest Chevron Chemical Co., Rolim and Haas Co., Stauffer Chemical Qo. and labels from
federally registered pesticide products.
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Table 2
Captan Use on Non-Agricultural Sites
1/
Site
pasta
paint
textiles
vinyl
lacquers
paper
rubber stabilizers
plasticizers
polyethylene
vinyl resins
packing boxes
wood
surface sprays
Estimated Annual
Usage Level (pounds a.l.)
<1,000 1,000-10,000 10,000-50,000 50,000-150,000
(usage included
in textiles)
undetermined
little or none
little or none
Products
principally wallpaper
paints for greenhouses,
medical facilities, food
packing plants, etc.
vinyl-ooated fabrics
(mattresses, mats# curtains, etc.)
above uses plus auto vinyl
roofs, aatroturf, others
very limited
plastic additive
garbage bags, pond liners
vinyl precursor
mildew control spray additive
J/ Captan is used to some extent in cosmetics, however usage estimates are not available*
Sourcei EPA estimates based on a telephone survey pf product manufacturers (Fall 1979) and data
available from industry studies.
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II. REGULATORY HISTORY
A. US DA. Actions
A joint U.S. Department of Agriculture-Department of Health,
Education and Welfare statement was published in the Federal Register
of April 13, 1966, for implementation of a National Research Gouncil
reccmmendation that "The concepts of 'no residue' and 'zero tolerance'
as employed in the registration and regulation of pesticides are
scientifically and administratively untenable and should be abandoned"
(FR 1966). Hie joint statement specified that registrations of all
uses involving a reasonable expectation of small residues on food or
feed at harvest should be discontinued as of December 31, 1967 unless
data were presented to support a finite tolerance or exemption frcm a
tolerance. Since no such evidence had been provided for the use of
captan on gooseberries, cancellation of this use was proposed.
The US DA Pesticide Regulation Division (PRD), issued severed
regulatory notices from January 10, 1968 to November 22, 1971
concerning safety studies, nonfood use restrictions, cancellation of
uses based on "no residue" or "zero tolerances," and one product
cancellation.
The PR Notice 68-3 of January 10, 1968 to Manufacturers, Ftormulators,
Distributors and Registrants of Economic Poisons announced that captan
uses for seed treatments were classified as nonfood uses (USDA 1968).
Therefore, registration of products for these uses was continued in
the absence of finite tolerances.
PR Notice 68-5 of January 30, 1968 concerned "no residue" and "zero
tolerance" registrations beyond December 31, 1967 (CSDA 1968a). This
was an extension of registration for uses of captan on asparagus,
gooseberries and packing boxes until January 1, 1969. However, the PR
Notice 68-8 of April 24, 1968 classified the uses of captan on
asparagus and packing boxes as nonfood uses (USDA 1968b). Hie uses
were therefore continued in the absence of data supporting finite
tolerances.
PR Notice 69-4, of February 1, 1969, announced that since no evidence
was provided to support a finite tolerance of captan on gooseberries
the use was cancelled (USDA 1969).
PR Notice 70-8 of March 10, 1970 requested registrants to undertake
the additional safety studies necessary to further evaluate captan
concerning its carcinogenic and teratogenic potential (USDA 1970).
Such tests were to include negative and positive controls.
Epidemiological data were also requested for persons with a known
history of high exposure to captan.
11
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The PRD cancelled the registration of Vancide 89RE on November 22,
1971. This was a technical grade product for manufacturing and
formulating use. The cancellation action was taken pursuant to
Section 4(c) of FIFRA (now superceded by FIFRA Section 6(b) as
amended in 1978) due to the registrant's lack of response to the
January 8, 1971 notice of intent to cancel.
B. Other Agency Reviews and Findings
The Report of the Secretary's Commission on Pesticides and Their
Relationship to Environmental Health by the U.S. Department of Health
Education and Welfare, reviewed the significance of adverse effects
data on a number of pesticides, including captan (Mrak et al., 1969).
The Commission recommended unanimously that human exposure to captan
be considered a potential health hazard. The following were among the
Canmission' s findings relating to captan:
1) it was reported as a cause of dermatitis from apple spraying
and allergic dermatitis was demonstrated in agricultural vrorkers;
2) it produced mutagenic effects in bacteria, human embryonic lung
cells and cell lines derived frcm the kidney of the kangaroo rat?
3) it induced teratogenic effects in developing chicken embryos; and
4) it increased tumor incidence in mice, with a significance
level of p = 0.02.
The Canmission specifically recommended: 1) reducing exposure of the
general population fron dietary sources of captan pending the
completion and evaluation of additional testing of tumorigenicity;
2) minimizing workers' exposure to captan pending completion of safety
studies; 3) giving high priority to captan in a testing program for
mutagenesis; and 4) restricting captan immediately should it be found
to be teratogenic.
Summary results of a National Cancer Institute bioassay of captan for
possible carcinogenicity in rats and mice were published in the
Federal Register (FR 1977). Tumors in the duodenum of mice were
associated with captan treatment. There was no convincing evidence
that tumors observed in rats were related to captan treatment.
C. Other Regulatory Actions
The Chited States Department of Labor, Wage and Hour Division,
published final rules pertaining to captan in the Federal Register
(FR 1979). The notice indicated that while current regulations
provided for the issuance of waivers permitting employment of 10- and
11-year old minors in hand harvesting of short-season crops, because
12
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captan was a suspected carcinogen, no waiver could be issued for
minors to harvest captan-treated crops of strawberries or potatoes.
The Environmental Protection Agency's Office of Water Planning and
Standards (CWPS) en February 16, 1979 published amendments to the
final rule designating captan as a hazardous substance (FR 1979).
This action was taken in accordance with the Clean Water Act (CWA) for
the control of the discharge of hazardous substances. The CWPS also
required that all facilities discharging 10 pounds or more of captan
to waters or shoreline report that fact in accordance with Section 311
of CWA. Further, facilities which discharge captan are regulated by
CWA Sections 309 and 402 and are required to ccmply with National
Pollutant Discharge Elimination System Permit regulations.
Chder 21 CFR 176.170 the FDA has established regulations concerning
captan as a component of coatings for paper or paperboard surfaces
that contact food. The chemical may be used as a mold— and mildew-
proofing agent in such coatings. The amount of captan permitted as a
component of the coatings depends on the particular type of food which
will contact it. The permissible concentration of captan is
established by a determination of the amount of the chemical that can
be extracted with certain solvents under certain conditions.
Following an adverse inspection report from the Food & Drug
Administration concerning the laboratory testing practices of
Industrial Bio-test Laboratories (IBT), the EPA Deputy Assistant
Administrator for Pesticide Programs notified all registrants that
studies conducted by IBT and used in support of their pesticide
registrations must be audited (Johnson, 1977 and 1978). There were 12
such audits completed on May 15, 1979 by registrants of products
containing captan. The audits disclosed a large number of IBT
testing deficiencies and resulted in the Agency's determination that
none of the 12 studies were valid (Auerbach, 1980).
13
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III. SUMMARY OF SCIENTIFIC EVIDENCE TO SUPPORT REBUTTABLE PRESUMPTION
A. Oncogenicity
40 CFR Section 162.11(a)(3)(ii)(A) provides that "a rebuttable
presumption shall arise [that a notice of intent to cancel
registration shall be issued] if a pesticide's ingredient(s),
metabolite(s), or degradation product(a)... induces oncogenic effects
in experimental mammalian species or in man as a result of oral,
inhalation, or dermal exposure..." Section 162.3(bb) defines the term
oncogenic as "the property of a substance or mixture of substances to
produce or induce benign or malignant tumor formation in living
animals."
The Agency has concluded that all pesticide products containing captan
exceed the chronic risk criterion relating to oncogenicity. This
finding is based on the studies presented below. In sunmary,
significantly elevated incidences of intestinal and liver tumors were
observed in male mice following 20-month and 18-month oral
administrations of captan, respectively. Two long-term rat studies
resulted in no significantly increased levels of tumors. One rat
study and one mouse study were determined to be invalid and therefore
cannot be used in evaluation of captan.
Gulf South Research Institute conducted a bioassay for the National
Cancer Institute (NCI, 1977) utilizing B6C3F1 mice and Osborn-Mendel
rats. The mouse treatment groups consisted of 50 male and 50 female
mice per dose level with 10 matched controls per sex. A pooled
control group was formed using the matched controls and an additional
70 control animals per sex fran other studies being conducted at that
time. Captan, at 8,000 and 16,000 ppm, was administered to 35-day-old
mice in their diet for 80 weeks. The mice were sacrificed after 11
additional weeks on a control diet. A dose-related increase in the
incidence of duodenal tumors (adenomatous polyps and polypoid
carcinomas) was seen in both males (pooled controls 0/63, low dose
1/43, high dose 3/46, p =0.033) and females (pooled controls 0/68, low
dose 0/49, high dose 3/48,p = 0.022). The rarity of these lesions in
this particular strain of mice increases the likelihood that the
lesions were caused by the administration of captan. Decreased
incidences of hepatomas and lung tumors were also noted in the results
of this study. However these observations do not obviate the Agency1s
concern about the increased duodenal tumors.
Preliminary results fran a registrant sponsored (Stauffer Chemical
Co. and Chevron Chemical Co.) 2-year mouse study appear to confirm an
increased incidence of duodenal tumors among captan-treated mice.
However, the Agency has not scientifically evaluated these data or
made any conclusions concerning such results (Incomplete Study-Not
Referenced).
14
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Innes et al., 1969, administered captan daily to groups of B6C3F2 and
B6AKF1 mice. Eighteen males and 18 females were used for each strain,
at a dose of 215 mg/kg/day by gavage frcm the 7th day of age to the
28th day. Frcm the 28th day to the end of the study, captan was
administered in the diet at 560 ppn. These same authors reported an
increased incidence of hepatomas in males only (p<0.05) (Bionetics,
1968). A reanalysis of the data in the Mrak report (1969) using the
Mantel-Haenzel method gave a significance level at p<0.02 for the
hepatomas in males. The tumor incidence among captan-treated females
was not significantly elevated. The ability of this study to detect
increased tumors was poor, however, since the number of animals was
too small, it continued only 18 months, and only one dose level was
used (much lower than that in the 1977 NCI mouse study).
The NCI (1977) rat study treatment groups consisted of 50 animals of
each sex per dose level and 10 matched controls per sex. An
additional 65 animals per sex were used for a pooled control group.
The 35-day-old rats were given 8,000 or 16,000 ppm captan in their
diet. The high dose level proved to be too toxic and the group was
dropped frcm the study at 18 weeks. A new low dose group was started
at 4000 ppm. Twenty-one weeks later the dosage of both groups was
halved, resulting in time-weighted average doses of 2,525 and 6,050
ppm for the 80 weeks of treatment. The rats were sacrificed after an
additional 33 weeks. No lesions were seen which could be attributed
to captan, however the authors reported that: "In rats a positive dose-
related trend and a difference between incidences of tumors in high-
dose and pooled-control groups were found in females when the data for
adrenal cortical adencma were combined with those for adrenal cortical
carcinoma (pooled controls 0/64, low-dose 2/50, high-dose 3/47,
p=0.047). There was also a positive dose-related trend for the
incidence of C-cell adencma of the thyroid in female rats (pooled
controls 1/66, low-dose 1/49, high dose 4/44, p = 0.0035)."
A study by Hazelton Laboratories (1956) used even fewer animals (10
male and 10 female rats per group) for a 2-year captan feeding study.
Substantial mortality occured in many of the groups, including 50% of
the control males and 40% of the control females. The high dose group
(10,000 ppm) was sacrificed at oily 55 weeks, which was insufficient
time for tumor development. The medium and low dose groups (5000 and
1000 ppn) were sacrificed at 104 weeks. No tumors that could be
associated with captan were seen; however, the ability of this study
to detect tumors was very poor due to the small sample size and short
term of the high dose testing.
A 15-month mouse study (IBT B9271) and a 2-year rat study (IBT B9267)
have been judged invalid by a joint US/Canadian governmental audit
(Auerbach, 1980).
15
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Mutagenicity
40 CFR Section 162.11(a)(3)Cii)(A) states that "a rebuttable
presimption shall arise [that a notice of intent to cancel
registration shall be issued] if a pesticide's ingredient(s),
metabolite(s), or degradation product(s)... induces mutagenic effects,
as determined by multitest evidence." Section 162.3Cy) defines
mutagenicity as "the property of a substance or mixture of substances
to induce changes in the genetic complement of either somatic or
germinal tissue in subsequent generations." Section 162.3(1) defines
degradation product as "a substance resulting from the transformation
of a pesticide by physiochemical or biochemical means."
Human exposure to a mutagen has serious implications. The
possible adverse effects to people, especially those of
reproductive age,, are spontaneous abortions, stillbirths, birth
defects in their children, and diseases in the adult life of
subsequent generations. Any of these effects could result from
exposure of the male and/or female parent to a mutagen. In
addition, those exposed can be adversely affected by mutations of
the scmatic cells.
The primary objective of mutagen testing is to determine whether a
chemical has the potential 'co cause heritable genetic alterations in
man. Direct methods for this assessment do not exist. As a
consequence, non-hunan and even non-marmialian tests have been utilized
in efforts toward this assessment (DHEW, 1977).
Evidence in both prokaryotic (i.e. bacterial) and eukaryotic (i.e.
mammalian) systems indicates that captan is a point (gene) mutagen.
This means that captan can interact with DNA of several species to
produce mutations in both reproductive and other body cells. There is
also evidence that captan can induce chrcrnosanal aberrations in
somatic cells of mammals. In addition, available data indicate that
captan can dan age DNA of both prokaryotic and eukaryotic organisms.
Though not all of the available mutagenicity data are presented in
this dociment, the following representative data support the Agency's
conclusion that captan is capable of inducing gene mutations,
DNA damage and chromosomal aberrations and therefore meets this risk
critrion. Additional mutagenicity data are being sought primarily
through registrant compliance with FIFRA Section 3(c)(2)(b) requests
(Johnson, 1980).
1. Gene Mutations [Data Summarized in Table 3]
Gene (point) mutations are alterations which affect single
genes. These alterations include base pair substitutions and
frameshift mutations as well as other small deletions and
insertions. Applicable in vitro test systems include both
forward and reverse mutations assays in bacteria, yeast, fungi,
16
-------
Table 3
Reference
Bridges et al ~,
1973
Bridges et al.,
1972
Buselmaier et al.,
1972
Ficaor et al«,
1977
Test
forward mutation
reverse nutation spot test
mouse host-mediated
reverse mutation
Reverse mutation*
mouse host-mediated
rat host-mediated
in vivo mouse blood
- urine mediated
GENE HUTATIONi BACTEKIA
Organism
Escherichia coll
B. coli
Salmonella typhlmurlum G46
Serratla marceecena
8. typhlmurium G46
8. typhlmurlum TA 1950
S. tvphlmurluiB G46
Results
+
Comments
Mo metabolic activation
No metabolic activation
500 mg/kg captan inj ected
intra peritoneal
1,000 mg/kg orally
3 subcutaneous inj ectlons
2,000 mg/kg orally of 500
mg/kg
urine mediated
in vivo rat-blood-mediate4
in vivo reverse mutations
assaysi
captan + saline
captan + rat blood
captan + rat plasma
captan + human blooc}
captan + S-9 rat liver
microsome fraction
8. typhlmurlum TA 1950
S. typhlmurlum TA |950
S. typhlmurlum TA 1950
S. typhlmurlum TA 1950
8. typhlmurlum TA 1950
S. typhlmurium TA 100
- {decreased)
+
- (decreased)
revertants/plate 367 without
8-9 109 with S-9
Ficsor et al.,
19/8
reverse mutation
S. typhlmurlum G46
TA 1530, TA J950, TA 100
Used as positive control in
spot and liver suspension
assays. 8-9 metabolic
activation system with TA 1(
reduced the mutagenicity
-------
Reference
Gabridge and
Legator, 1969
Legator et al., |969
Harshall et al., 1976
McCami et al.# 1975
Nagy et al., 1975
Teat
Mouae host-nediACot)
reverse mutation spot teat
Reverse mutation spot teat
Revaraa mutation plate teat
Reverse mutation spot teat
Reverae nutation apot teat
Seller, 1975
Shiraau et al., 1976
Reverae mutation apot teat
Reverae mutation apot teat
Table } (Continued)
GENE MUTATtOMi BACTKHT A
~
Organism
8. typhlmurlum Q ^
sail
3. typhlmurlum ?k $535,
fl. typhlmurlum TA J539
S. typhlmurlum 94 1535
TA 100, TA 90
ft. coll u? 2 jcry-hcr*
£i coM UP 2 fry-hcr-
fl. typhlmurlum TA 1535
B. coll W 2 try-fccr*
|S. coll WP 2 ticy-hor-
a. typhlmurlum TA 1535
fl. typhlmurlum TA 1536
1537, %k 153d
fteaults Comments
t
Too few organiaws recovered
not we!} describe*}.
t Approximately 1/2 aa mutagenic
after metabolic activation.
No metabolic activation used
"strong mutagen".
Inconclusive protocol and results not
adequately described.
t
t
-------
Reference
Simmon et al«, 1977
Test
Reverse mutation plate
test
Szybalski, J958
Reference
Blgnami et al., 1977
Reverse nutation spot
Assay
Point nutation
Arlett et al«, 1975
Ouabain resistance
induction
Table 3 (Continued)
GENS MUTATIONI BACTERIA .
Organism
B. coll HP 2 uvr A-
Results
Comments
S. typhinurlum TA 1535,
TA JOQ
fl. typhlmurlum
TA 1537, TA 1538
B. coll Sd - <$
Inconclusive
Base pair substitution.
No sufficient information to
evaluate*
GENE MUTATIONi EUKARYOTIC
MICROORGANISMS
Organism
Aspergillus nldulans
Results
Comments
No metabolic activations used.
GENE MUTATIONS; MAMMALIAN
CELLS IN CULTURE
Chinese hamster SAG
suspension inde-
finite treatment
Ouabain, suspension treatments t
lung fibroblast SAG and Ouabaip, t
vapor treatment cells
-------
and mammalian cells in culture. The lower prokaryotic (e.g.,
bacteria) systems detect only point mutations, while higher
eukaryotic systems detect multi-locus deletions as well.
The information available as given below on the mutagenicity of
captan has shown that it can cause gene mutations in bacteria,
in eukaryotic microorganisms and mammalian cells in culture.
a. Bacteria
As an example of bacterial testing to indicate mutagenicity,
many mutants have been isolated which block various steps in
histidine biosynthetic pathways of Salmonella typhimurium.
Among these mutants, a series of tester strains have been
used in testing captan which revert by specific mechanisms,
e.g., base-pair substitution or frameshift mutations (CHEW,
1977).
Captan has been demonstrated to produce reverse mutations in
Salmonella typhimurium G46, TA 1535, TA 100, and TA 1950
(Ficsor et al., 1977; Ficsor et al., 1978; Marshall et al.,
1976; McCann et al., 1975; Shirasu et al-, 1976; and Simmon
et al., 1977). Marshall et al., (1976) found a mutagenic
response in a plate test with S^ typhimurium TA 1537.
However, Shirasu, et al. (1976) and Simmon et al. (1977)
observed no response with this strain.. Reverse mutations
were also induced in the very sensitive frameshift mutant TA
98 (McCann et al., 1975). Captan appears to be more active,
however, in base pair than in frameshift mutation.
Escherichia coli WP 2 has been shown to be susceptible to
the mutagenic action of captan. This tryptophan auxotroph
was reverted to non-dependence on tryptophan by captan
(Nagy et al., 1975; Shirasu et al., 1976; and Sinnon et al.,
1977).
Bridges et al. (1973), found that captan caused a
forward nutation to colicin E 2 resistance in E^ coli WP 2
uvr A-. A streptomycin dependent strain (SA4-73) and a
thymine dependent strain were shown to revert to
streptomycin independence and thymine independence (Legator
et al., 1969). This effect demonstrated that captan can
cause point mutational changes in these strains.
A spot test using various strains of E^ coli WP 2 was
designed to detect volatile mutagenic components of captan
(Bridges et al., 1972). Captan impregnated filter
paper was placed on the agar surface or on the lid of the
petri dish. Approximately equal numbers of mutants were
observed in each case, indicating that most of the effect of
20
-------
captan was mediated by a volatile mutagen. The frequency
of mutation was increased as the buffer pH increased from 5
to 9 on the filter paper on the lid. The vapor phase
mutagen was also demonstrated to be short-lived.
Fewer survivors were observed with an ExrA- strain than with
an ExrA+ strain when the captan impregnated filter pad was
applied to the agar, but not when it was applied to the lid
and not in contact with the agar. This indicates that there
is a second mutagenic (diffusible) component of captan
causing repairable DNA damage. Hie diffusible component
causing the effect was not identified.
Bacteria with Metabolic Activation
A number of systems have been developed to simulate the
metabolic capabilities of intact manmals. The various
metabolic activation systems used can be grouped into
three main categories: (1) Whole animals are employed to
activate the test chemical.. The systems most ccmmonly used
are the host-mediated assay and the analysis of body fluids
for the presence of mutagens.. (2) Certain strains of
mammalian cells in culture are capable of metabolizing
chemicals. These are used as feeder cells for the indicator
cells which do not have such metabolizing capabilities.
(3) Organ hcmogenates from manmals are used to metabolize
chemicals in an in vitro system in the presence of the
indicator organism (DHEW, 1977). These bacterial assays
employ an exogenous source of metabolic activation in the
form of a manmalian liver microsomal preparation. The
majority of genetic toxicants must be converted into
reactive forms before their effects can be detected.
S-9 liver microsome fractions generally seem to decrease
the mutagenicity of captan in microbial assays. Whole
blood, but not plasma, also decreases the activity in
bacterial systems.
Ficsor et al., (1977) examined the mutagenic activity of
captan on Sj_ typhimurium TA 100 after incubation with a rat
S-9 microsomal fraction and found an approximately 33%
reduction in mutagenic activity over the untreated captan
assay. Rat S-9 microsomal fraction decreased the muta-
genicity of captan by approximately 50% in typhimurium
strains TA 1535 and TA 1537 (Marshall et al., 1976).
Decrease in nutagenic activity after treatment of captan
with S-9 microsomal fraction was also noted in S.
typhimurium strains TA 100 and TA 1535 by Simmon et al.,
(1977).
21
-------
Host-and Fluid-Mediated Bacterial Systems.
Host-Mediated Assay In t^e host-mediated assay, the
indicator organism is introduced into the peritioneal cavity
or injected into the circulatory system or the testes of the
host mairmal. The tost is then treated with the substance
under test, sacrificed, and the test organism removed and
examined for mutation induction. A wide range of cellular
systems have been used as indicator organisms: Salmonella,
E. coli, Saccharcmyces, Neurospora, mouse lymphoma cells,
Chinese hamster cells, mouse ascites cells and human
lymphocytes.
Fluid-Mediated Assay . After chemicals are metabolized
in an animal, they may be excreted in the urine as breakdown
products and/or conjugates of the original substance.
Microbial indicators have proven useful for the detection
of active mutagens in the urine of animals treated with
non-mutagenic precursor substances (DHEW, 1977).
S. typhimurium G46 his- and Serratia marcescens a21 leu
were injected intraperitoneally in NMRI mice previously
injected subcutaneously with 500 mg/kg captan (Buselmaier
et al., 1972). After 3 hours, the bacteria were
recovered and examined for reverse mutations. Mutagenic
responses were seen for both organisms.
Ficsor et al., (1977) performed several host- and fluid-
mediated assays with captan using strains of S^_ typhi-
murium . Four host-mediated assays were performed as
described below. None of than evidenced any increase in
mutagenic activity attributable to captan. (1) Upjohn
strain Suris albino male mice were injected intraperito-
neally with strain G46. One group was given captan orally
at 1,000 mg/kg and another group was given 500 mg/kg captan
subcutaneously at 0, 60, and 120 minutes after injection of
the bacteria. Hie bacteria were recovered and examined for
revertants. (2) Sprague-Dawley male rats were injected
intraperitoneally with strain TA 1950 and given 2,000 mg/kg
captan orally. The bacteria were recovered after two hours
and examined for revertants. (3) A spot assay with strain G
46 was performed using filter discs dipped in blood or urine
frcm mice treated orally with 250 mg/kg captan. (4) Spot
assays with strain TA 1950 were performed by placing 3 drops
of blood frcm rats (after oral or intraperitoneal captan
treatments)on the assay agar. Quantitative determinations
were performed by incubating blood from each sample with
strain TA 1950 before plating.
Fluid-mediated assays were performed with strain TA 1950
using human blood, rat blood, plasma, and saline. When
captan was incubated in rat blood, the mutagenicity of
22
-------
captan was inactivated at 500 and 1,000 ug/ml captan, but
not at 5,000 and 10,000 ug/ml. Captan was mutagenic in
saline, in the absence of rat blood. Rat plasma was
inactivated by 20 ug/ml captan, but not 200 ug/ml.
The researchers reported that this inactivation could be
attributed to captan's reaction with glutathione localized
in red blood cells. Human blood inactivated about as much
captan as rat blood.
d. Eukaryotic Microorganisms
Captan was examined in a point mutation assay using a
haploid strain of Aspergillus nidulans (Bignami et al.,
1977). 8-azaguanine resistant mutations were reported.
e. Mammalian cells in culture
Captan was used to treat cell cultures of V79-4 Chinese
hamster lung fibroblasts (Arlett et al., 1975). Treatment
with captan in suspension resulted in no absolute increase
in the number of 8-azaguanine resistant colonies per plate.
However, both the absolute number of ouabain resistant
colonies and the number of variants per survivor were
increased by captan at 5 and 10 ug/ml. Exposure to vapor
frcm captan impregnated filter paper resulted in an increase
in the number of both 8-azaguanine and ouabain resistant
colonies.
ENA Coinage [Data Summarized in Table 4]
DNA repair tests do not measure mutation per se , but DNA damage
induced by chemical treatment of a cell. Microbial test systems
measure this damage as cell killing. Mammalian cell systems -
both in vitro and in vivo — measure the damage to DNA either
directly, or as it is being repaired (CHEW, 1977).
Captan has been shown to cause DNA damage in bacteria,
eukaryotic microoganisms, and in two mammalian cell lines.
Prokaryotic and Eukaryotic Microorganisms
This test is usually performed as a plate test with the chemical
deposited in the center of a lawn of the coli or Salmonella
typhimurium tester strains. The killing effects aremeasured as
zones of bacteria growth inhibition and the ratio of the size of
the zones between the normal and the repair-deficient strains is
a measure of the differential killing effects. Hie test has also
been performed by applying the test substance to one end of two
or more streaks of indicator organisms on a single petri dish and
looking for a differential shortening of the streaks. This
allows for the simultaneous use of more than one type of repair-
deficient strain on a single plate. This method has been used
23
-------
with Bacilus subtilis and Saccharomyces cerevisiae
Mammalian cells synthesize DNA only during one stage of the
cell cycle. This is referred to as "scheduled DNA synthesis."
However, when the cellular ENA is damaged, repair synthesis can
occur during the time when scheduled ENA synthesis is not taking
place. This "unscheduled ENA synthesis" can be measured in
synchronously growing cells as uptake of radioactive thymidine
into the cell's ENA. It can be measured in cells in culture, or
in meiotic and post-meiotic mouse spermatocytes in vitro (DHEW,
1977).
a. Bacteria
Captan was shown to cause differential killing of ENA repair
deficient strains of the following bacteria: E^ coli WP 2
and E. coli WP 2 uvrA (Bridges, B. A. et al., 1973),
Bacillus subtilis H17 rec+/B. subtilis M45 rec- (Shirasu
et al., 1976; Simmons, et al., 1977), and E. coli W311
ploA+/ E. coli P3478 polA-(Simmons, et al., 1977).
b.. Eukaryotic Microorganisns
Aspergillus nidulans, diploid strain P, was used for a
mitotic segregation assay in which scmatic crossing over was
attributed to captan treatment (Bignami et al., 1977).
R. Fahrig (1973) found gene conversion at two loci, ade 2
and trp 5, in Saccharomyces cerevisiae after treatment with
captan.
c. Manmalian Cells in Culture
An SV-40 transformed human fibroblast cell line, VA-4, was
treated with captan, with and without rat liver S-9 micro-
scme fraction (Ahmed et al., 1977). A significant (p<0.05)
increase in unscheduled ENA synthesis as measured by
autoradiography was seen at all treatment levels. However,
metabolic activation did not significantly alter the effect
of captan.
Swenberg et al. (1976) found an increase in the rate
of elution of single-stranded ENA frcm polyvinyl filters
after lysing V79 Chinese hamster lung fibroblast cells
treated with captan. No effect was seen when an S-9
microsomal fraction was added with the captan treatment.
Uiis indicates that captan can cause breaks in ENA.
Preceding page blank
25
-------
3. Chromosomal Aberrations [Data Summarized in Table 5]
Chromosomal aberrations involve changes in number and structure
and may include the loss or gain of entire chromosomes,
chromosome breaks, nondisjunctions, and translocations. Tests
for these abnormalities involve searching for chromosomal changes
in somatic and germinal cells usually obtained from insects and
mammals•
Chromosomal aberrations have been reported in two mammalian cell
lines. Of the literature examined so far, in vivo tests (which
are generally less sensitive than the in vitro tests) have not
revealed significant indications of mutagenicity of captan with
the exception of the dominant lethal test in Osborne-Mendel rats
and CBA-J mice (Collins, 1972).
a. Mammalian Cells in Culture
Manmalian cells in culture can be employed for the
assessment of chromosomal effects. Human cells, e.g.
fibroblasts and lymphocytes, and Chinese hamster ovary cells
with and without metabolic activation have been used. Gross
chronoscmal aberrations such as breaks, gaps, and
rearrangements can be readily observed in these systems
(CHEW, 1977).
A heteroploid human embroyonic lung cell line, L-132, and a
line of rat-kangaroo cells were treated with captan
(Legator et al., 1969). Mitosis and DMA synthesis were
inhibited. A 36% increase over control levels in chromosome
breaks was observed 2 hours after addition of captan at 10
ug/ml to the L-132 line. The increase was 41% at 4 to 5.5
hours and 14% at 24 hours after addition of captan.
Infrequent exchange figures were also observed at 24 hours.
In the rat-kangaroo line, captan also increased the
frequency of cells with chromosome breaks, preferentially in
the X chromosome. A dose-response effect was apparent.
Tezuka et al., 1978, treated diploid human fetus fibroblasts
with captan at 0.5 to 4 ug/ml captan. Mitosis was inhibited
at all dose levels and a dose-dependent increase in cells
showing stickiness was seen, statistically significant
(p<0.001) at the 3 and 4 ug/ml dosage levels. No increase
in chromosome gaps or breaks were seen and the stickiness
may not have been due to mutagenicity. Since the scoring
method was not described, the usefulness of this study was
limited.
The scoring criteria were not described for a cytogenetic
analysis of bone marrow cell preparations frcm Wistar rats
26
-------
Table 5
Reference
Legator et al., 1969
Tezuka et al., 1978
Assay
Cytogenetic
Cytogenetic
CHROMOSOMAL ABERRATIONSt IN VITRO CYTOGENETICS
Organism
Human embryo lung cells
Rat kangaroo cells
Human fibroblasts
Results
+
t
No Increase
in breaks or
gaps. Sticki-
ness dose
response seen
Comments
Pose related response in
chromosome breaks .
Stickiness may not be related
to mutagenicity
CHROMOSOMAL ABERRATIONSI IN VIVO CYTOGENETICS
Tezuka et al., 1978 Cytogenetic Wista? rats
CHROMOSOMAL ABERRATIONS t DOMINANT LETHAL IN RODENTS
Coll ins, 1972
Epstein et al., 1972
Kennedy, 1975
Simmon et al., 1977
Tezuka et al., 1978
Dominant lethal
Osborne-Mende} rats
CBA - J mice
ICR/H2 Swiss mice
Charles River mice
ICR/SIM mice
C3H and SLC-JCR mice
Relatively insensitive test
Not valid
Dosed up to 5 g/kg/day.
Not valid
-------
treated orally at single dose levels of 500, 1,000, or
2,000 rag/kg captan or five consecutive doses of 200, 400,
or 800 rag/kg (Tezuka et.al., 1978). No chromosomal effects
were reported.
There was a consistent, although statistically non-
significant, increase in gaps but this may have been due to
captan1s binding to proteins rather than an effect on DNA.
b. Dominant Lethal Tests
Dominant lethal effects in the mouse or the rat seen as
fetal wastage are consider to be indicators of chromosomal
mutation produced in germinal cells by mutagenic substances
(DHEW, 1977).
1) Collins Study
Dominant lethal effects attributable to captan were
reported in Osborne-Mendel rats and CBA-J mice
(Collins, 1972). Captan was given for 5 days by
intraperitoneal injection in doses of 2.5, 5.0, and 10
mg/kg/day or by oral intubation in doses of 50, 100,
and 200 mg/kg/day to groups of 15 rats and 15 mice.
The rats were mated with one virgin female each week
for the next 10 weeks. The mice were mated with two
virgin females each week, for 12 weeks ~ Caesarean
sections were performed on the 13 th day of pregnancy
for the rats and on the 12th day for the mice.
a) Results in Rats
Significant increases (p<0.05) were found in the
mean number of early deaths per pregnancy for
those pregnancies sired by rats 4 weeks after the
rats were given captan orally at a dose of 100
mg/kg/day. Increased early fetal deaths were also
found in pregnancies sired by rats at 1, 2, and 5
weeks after treatment with 200 mg/kg/day captan.
When the litter was considered an experimental
unit and affected litters were defined as those
with at least one early fetal death, a significant
increase (p<0.05) in the number of affected
litters was seen in the rat test group given 100
mg/kg/day orally and mated after 4 weeks. The
other two dose groups showed consistent increases
in the numbers of affected litters. In addition,
there were significant linear dose-response
relationships in affected litters from rats mated
3 and 4 weeks after treatment.
28
-------
When "affected litters" were defined as those with
two or more early deaths, the data showed a
significant increase (p<0.05) in the number of
affected litters for rats given a daily oral dose
of 100 mg/kg captan and mated 2 and 5 weeks later,
and (p<0.01) for rats given a daily dose of 200
mg/kg captan, and mated 1, 2 and 5 weeks later.
b) Results in Mice
There were also significant increases (p<0.05) in
the number of early fetal deaths per pregnancy
among the potential offspring of mice given 200
mg/kg/day intraperitoneally and mated 4 and 5
weeks later. Similar increases in the number of
early deaths per pregnancy were reported among the
offspring of mice given 100 mg/kg/day and 200
mg/kg/day orally and mated 1 and 2 weeks later.
The groups of mice given captan at the highest
doses showed significant increases (p<0.01) in the
percentage of litters with 2 or more early fetal
deaths for matings on week 5 after intraperitoneal
administration and on week 1 for oral
administration. Significant linear dose responses
were seen for different weeks of mating for all
combinations of species and routes:
intraperitoneally treated rats mated in weeks 4
and 5; orally treated rats mated in weeks 1 and 2;
intraperitoneally treated mice mated in weeks 1-3
and 5-7; and orally treated mice mated in weeks 1-
5, 9, and 12.
2) Simmon Study
Captan, administered at up to 5,000 mg/kg/day in the
diet for 7 weeks, did not increase the frequency of
dominant lethal mutations in ICE/SIM mice (Simmon et
al., 1977). Hie positive control was administered by
intraperitoneal injection.
3) Epstein and Kennedy Studies
The following dominant lethal tests, although reporting
no dominant lethal effects, are inconclusive as to
whether captan may cause such an effect. Epstein et
al., (1972) used ICR/Ha Swiss mice; however, the test
was relatively insensitive (i.e. unable to detect small
increased effects) since small group sizes were used
and the dosages ware low. The study performed by
Kennedy (1975) also used a low dosage and additionally
had no controls.
29
-------
4) Tezuka Study
Tezuka et al., (1978) treated C3H and SDC-ICR mice with
5 daily doses of up to 600 mg/kg/day captan; however
there were inconsistencies in reporting these
observations. Consequently this study is also
inconclusive as to whether captan may cause dominant
lethal effects. For example, application of the
formula given in the paper for calculation of the
percentage of dominant-lethal mutations yielded results
that differ from those reported. The protocol was not
standard, using only a 6-week post-treatment mating
period combined with a 2- to 4-day mating period. This
regimen may have allowed the more active males to
contribute more females to the experiment which may
have biased the results.
c. Heritable Translocation Test
Hie heritable translocation test and the sex chromosome loss
test have the capability of determining the heritability of
chromosomal damage. These effects are measured in progeny
of animals exposed to chemical mutagens. Thus, these assays
can be artployed not only as a means of detecting potential
mutagens but also for the purpose of assessing risk (CHEW,
1977).
A heritable translocation test was performed by Stanford
Research Institute (SRI) (project LSV-3493) for EPA
(Simmon et al., 1977). Captan was administered in the diet
for 8 weeks at levels of 2,500 ppm to 60 male ICR/SIM mice
and 5,000 ppm to 61 male ICR/SIM mice. These males, the 60
negative control males, and the 66 triethylenemelamine-
treated positive control males wsre mated with two females
each, except for one low dose and one high dose male that
were mated to only one female each. At maturity (10-12
weeks), 200 males were selected from each dose level group
and mated to three females each. The females were
sacrificed 14 days after mating and the uterine contents
were examined for live and dead implants as an indication of
sterility. A cytogenetic evaluation was made of meiotic
cell preparations from the testes of those males suspected
of being a translocate or non-breeder after two or three
breedings. One translocation was found in the high dose
group which would normally be sufficient to classify captan
as positive for heritable translocations; however, one
translocation was also seen in the negative control group.
This is the only heritable translocation found in over 1600
negative control males at SRI. This is an acceptable
historical spontaneous background rate for heritable
30
-------
translocations, however the presence of the event in this
study makes it impossible to evaluate the significance of
the heritable translocation in the captan-treated group. In
order to resolve this issue it would be necessary to re-run
this test, preferably using a larger number of animals.
C. Potential for Human Exposure
1. Introduction
The general population is exposed to captan by eating food which
contains captan residues. In addition, agricultural workers, and
occasionally bystanders, are exposed to much greater amounts of
captan when they are present in fields during or after captan
spraying. At present, the Agency has only limited data con-
cerning human exposure to captan. Additional data is being
sought, primarily through industry compliance with FIFRA Sec.
3(c)(2)(b) requests (Johnson, 1980), however data from any source
is welcome. Lhtil these data are available, Agency assessments
of human exposure will be made on a "worst-case" basis.
2. General Population
a. Dietary Exposure
Captan is registered for use on a large number of food
crops. Its use is extensive (Table 1) and there are a
number of established tolerances for raw agricultural
commodities (see Section I.B.2.) The Agency has calculated
that a theoretical worst-case dietary exposure would be
0.117 mg of cap tan/kg of body weight per day-' (Table 6).
b. Nondietary (Dermal & Inhalation)
There are a number of nonagricultural uses of captan. Seme
of the treated products (e.g., wallpaper paste), are used in
substantial amounts (Table 2) in or around domestic
dwellings; therefore, people who live or work in areas where
captan treated products are present may be exposed to captan
residues.
27 This calculation was based on existing tolerances, the extent
of crop treated (see Table 1), and an assumed average daily
diet of 1.5 kg for a 60 kg person. However, the Agency
anticipates that the actual levels of captan on treated crops
will be nuch lower.
31
-------
Table 6
Dietary "Worst Case" Exposure Calculations for Captan
Food Commodity or
Commodity Grouping
Almonds
Apples
Apricots
Avocados
Beans
Beet Greens
Beets
Blackberries
Blueberries
Broccoli
Brussel Sprouts
Cabbage, Sauerkraut
Cantalopes
Carrots
Cauliflower
Celery
Cherries
Collards
Corn, sweet
Cottonseed
Crabapples
Cranberries
Cucumbers, pickles
Dewberries
Eggplant
Garlic
Grapefruit
Grapes, raisins
Honeydew melons
Kale
Leeks
Lemons
Lettuce
Limes
Mangoes
Muskmelons
Mustard Greens
Nectarines
Onions (dry bulb)
Onions, green
Oranges
Food Factor
(% diet)
0.03
2.53
0.11
0.03
2.04
0.03
0.17
0.03
0.03
0.10
0.03
0.74
0.52
0.48
0.07
0.29
0.10
0.08
1.43
0.15
0.03
0.03
0.73
0.03
0.03
0.03
0.99
0.49
0.03
0.03
0.03
0.17
1.31
0. 17
0.03
0.03
0.06
0.03
0.72
0.11
2.17
Tolerance
Sjsssi
2.00
25.00
50.00
25.00
25.00
100.00
2.00
25.00
25.00
2.00
2.00
2.00
25.00
2.00
2.00
50.00
100.00
2.00
2.00
2.00
25.00
25.00
25.00
25.00
25.00
25.00
25.00
50.00
25.00
2.00
50.00
25.00
100.00
25.00
50.00
25.00
2.00
50.00
25.00
50.00
25.00
Percent of
Crop Treated
±/
42
32
21
100
50
10
100
100
100
50
50
100
50
50
50
50
13
50
50
80
100
50
100
100
50
100
50
30
50
100
100
9
84
9
100
100
100
21
100
50
V
h./
y
°y
¥
y
°i/
y
y
$
$
$
v
y
%
°°i/
°i/
y
y
¥
V
V
y
5i/
y
y
%
y
y
negligible
1/
Daily Intake
(mg/1.5kg
diet/day)
0.00038
0.30645
0.01733
0.01125
0.38250
0.04500
0.00510
0.01125
0.01125
0.00150
0.00045
0.02220
0.09750
0.00720
0.00105
0.10875
0.02070
0.00120
0.02145
0.00369
0.01125
0.01125
0.27375
0.01125
0.00563
0.01125
0.18563
0.11355
0.00562
0.00090
0.02250
0.00580
1.66043
0.00580
0.02250
0.01125
0.00180
0.00473
0.27000
0.04125
0.00000
32
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Table 6 (Continued)
Dietary "Worst Case" Exposure Calculations for Captan
Food Commodity or
Commodity Grouping
Peaches
Pears
Peas
Peppers
Pimentos
Pineapple
Plums, Prunes
Potatoes
Pumpkin, Squash
Quinces
Raspberries
Rhubarb
Rutabagas
Shallots
Soybeans
Spinach
Strawberries
Summer Squash
Tangerines
Taro
Tomatoes
Turnips
Turnip Greens
Watermelon
Food Factor
(% diet)
0.90
0.26
0.69
0.12
0.03
0.30
0.13
5.43
0.11
0.03
0.03
0.05
0.03
0.03
0.92
0.05
0.18
0.03
0.03
0.03
2.87
0.05
0.03
1.43
Tolerance
lEEEl
50.00
25.00
2.00
25.00
25.00
25.00
50.00
25.00
25.00
25.00
25.00
25.00
2.00
50.00
2.00
100.00
25.00
25.00
25.00
0.250
25.00
2.00
2.00
25.00
Percent of
Crop Treated
oy
£/
w
0^
&
100.0~
17 3~
4/
66.4~,
21
5
50
50
100
100
,02/
100. Of
100.0f
50 "°2/
100.0~\
'°¥/
100.0~,
100
100
¦°V
100.0-'
100.of
5°*°2/
100.04-,
71
4/
100.0y
100. Or'.
100. o^
Daily Intake
(mg/1.5kg
diet/day)
0.14175
0.00536
0.01035
0.02250
0.01125
0.11250
0.01686
1.35207
0.04125
0.01125
0.01125
0.00937
0.00090
0.02250
0.02760
0.07500
0.06750
0.01125
0.00563
0.00011
0.76539
0.00150
0.00090
0.53625
TOTAL
7.013255
_1/ Based on data as provided to EPA by registrants (Table 1).
2/ No usage data available, hence 100% assumed.
3/ Based on data estimates made by EPA (Table 2).
4/ Includes seed treatment useage which may not be relevant to dietary exposure
33
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3. Workers
a. Agricultural
1) Applicators, Mixers, Loaders and Bystanders
a) Commercial
Michigan farm workers were studied (Oudibier et
al. 1974) to determine the extent of their
respiratory exposure to captan. These farmers
used airblast speed sprayers drawn through the
orchards by tractors. Personnel involved with the
mixing and spraying procedures wore respirators
equipped with filter pads and midget impingers
containing ethylene glycol. Hie latter device was
connected to a vacuum source and used to monitor
pesticide levels in the breathing zone. After
each spray operation the respirator pads and the
impingers were analyzed for captan residues. The
respirator pad analyses indicated that respiratory
exposure was generally greater for mixers (0.8-1.9
qg/min) than sprayers (0.07-0.66 cjg/min).
Although no captan residues were found in the
impinger samples the researchers reported
difficulties with this sample collection
methodology.. A number of weaknesses in the
published report were identified as follows:
1) No mention of the type of. formulation used;
2) No recovery studies reported for the method-
ology used; 3) No indication of the dates of
sample collection or the dates of the analyses;
and 4) No detection limit given.
Captan exposure of farm workers in Maryland was
studied (Hansen et al., 1978) during 16 separate
orchard sprayings using a tractor-drawn, high-
pressure sprayer equipped with a single-orifice
handgun. Three men were involved in each
spraying: the tractor driver, the sprayer
operator and the observer. Following each
spraying the exposure was determined from captan
residues on respirator pads and patches attached
to clothing and on orchard foliage.
The average dermal exposure was calculated to be
1.96 mg/person/hr with a maximum of 3.3
mg/person/hr. This was2based on an assumed dermal
exposed area of 0.294 m when no protective
clothing was worn. The amounts of captan residue
collected frcm respirator pads of the tractor
driver and sprayer operator averaged 0.032 mg/hr,
34
-------
with the highest concentration sample obtained
frcm any one worker being equivalent to 0.081
mg/hr. The urinalysis data were not reported.
The captan residues on orchard foliage will be
discussed under Section 2(a)(2).
b) Heme Gardeners
The Agency is also concerned about possible
exposure of heme gardeners and orchard owners
during application of captan. Hie Agency will
solicit further information on this exposure in a
FIFRA Section 3(c)(2)(B) letter to registrants.
2) Harvesters
Hansen et al. (1978) observed that captan residues on
fruit diminish with time. The study found that the
average captan residue on apples was 190 ppn at
4 hours following application, but then declined to 53
ppm after 14 days. Such information indicates residues
of captan diminish following application, which shows
that the period between application and reentry for
harvesters may be of concern, as there is no
established preharvest interval.
b. Nonagricul tural
No information is available to the Agency for evaluating the
occupational exposure potential frcm nonagricultural uses
of captan (Table 2). The Agency requests such data in order
to evaluate the likelihood of captan exposure to
applicators, mixers, loaders and bystanders as well as to
those who handle the treated materials.
35
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IV. OTHER RELEVANT ADVERSE EFFECTS
40 CFR Section 162.11(a) (3) (ii) (B) states that "a rebuttable presumption
[that a notice of intent to cancel registration shall be issued] if a
pesticide's ingredient(s), metabolite(s), or degradation product(s) ...
produces any other [other than oncogenic or mutagenic effects] or delayed
toxic effect in test animals at any dosage up to a level, as determined by
the Adminstrator, which is substantially higher than that to which humans
can reasonably be anticipated to be exposed, taking into account ample
margins of safety."
Captan may produce other chronic or delayed toxic effects to organs and
functions of the body including the lungs, central nervous system,
hematopoietic system, metabolism, kidneys, reproductive systems and others.
Currently available data strongly suggest that captan may have
teratogenic, fetotoxic and hypersensitivity effects. The Agency is
currently seeking more information on these issues. If, upon further
evaluation of all the toxicity and exposure data the Agency determines that
other such adverse effects are produced by exposure to captan at any level
up to a level exceeding possible human exposure (taking into account ample
margins of safety), thai the Agency will issue a supplemental notice or
notices of rebuttable presumption against registration (RPAR)(s).
In addition, a supplemental RPAR may be issued on any of the uses of captan
which result in an acute hazard to aquatic species of wildlife as defined
in 40 CFR Section 162.1(a)(3)(i)(B)(3).
36
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CAPTAN BIBLIOGRAPHY
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37
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Fahrig, R. (1974) Canparative mutagenicity studies with pesticides.
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38
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39
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40
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[Production Data]
41
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