United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508C)
EPA-738-F-04-008
July 2004
R.E.D. FACTS
Pesticide
Reregistration
Ziram
All pesticides sold or distributed in the United States must be registered
by EPA, based on scientific studies showing that they can be used without
posing unreasonable risks to people or the environment. Because of advances
in scientific knowledge, the law requires that pesticides which were first
registered before November 1, 1984, be reregistered to ensure that they meet
today's more stringent standards.
In evaluating pesticides for reregistration, EPA obtains and reviews a
complete set of studies from pesticide producers, describing the human health
and environmental effects of each pesticide. To implement provisions of the
Food Quality Protection Act of 1996, EPA considers the special sensitivity of
infants and children to pesticides, as well as aggregate exposure of the public
to pesticide residues from all sources, and the cumulative effects of pesticides
and other compounds with common mechanisms of toxicity. The Agency
develops any mitigation measures or regulatory controls needed to effectively
reduce each pesticide's risks. EPA then reregisters pesticides that meet the
safety standard of the FQPA and can be used without posing unreasonable
risks to human health or the environment.
When a pesticide is eligible for reregistration, EPA explains the basis for
its decision in a Reregistration Eligibility Decision (RED) document. This fact
sheet summarizes the information in the RED document for Ziram one of four
chemicals in reregistration case 2180.
Use Profile Ziram is an agricultural fungicide registered to control fungal diseases on a
wide range of crops including stone fruits, pome fruits, nut crops, vegetables and
commercially grown ornamentals. In addition, it is formulated as a rabbit
repellent for outdoor foliar applications to ornamentals and as an additive in
industrial adhesives, caulking, and latex paints. The total annual domestic use of
ziram is approximately 1.9 million pounds of active ingredient.
Regulatory Ziram was first registered in the United States in 1960 as a broad spectrum
History use fungicide to control the scab in apples and pears, leaf curl in peaches, and
anthracnose and early blight in tomatoes. In 1981, additional uses were added to
the label for controlling leaf blight and scab in almonds, shot-hole in apricots,
brown rot and leaf spot in cherries, scab and anthracnose in pecans, and leaf spot,
rust and powdery mildew in ornamentals. Other registered uses of ziram include
homeowner application on residential ornamentals as a rabbit repellent and
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industrial application as a preservative in exterior latex paint, caulking, sealants
and wall boards.
Human Health Toxicity
Assessment The mechanism of toxicity for ziram has not been fully investigated;
however the primary target organs appear to be the nervous system, liver, and
thyroid. Ziram has moderate acute toxicity. It has been placed in a toxicity
category II/III for oral and dermal exposure, in category II for inhalation
exposure, in category I for eye irritation, and in category IV for skin irritation.
Ziram is a moderate skin sensitizer, and is classified as "suggestive of
carcinogenicity" to humans.
Dietary Exposure (Food and Water)
EPA has assessed dietary risk by estimating exposure to ziram residues
from consumption of food and drinking water. Both chronic and acute food
risks, as measured by the Population Adjusted Doses (PAD) are below the
Agency's level of concern. Since ziram residues are primarily found on the
surface of the fruit and are not systemic in nature, applying a washing
reduction factor (0.15) to the acute residues was a practical way to refine the
residues in fruits. When a washing reduction factor of 0.15 was applied to the
residues of all commodities (except nuts and berries) the maximum acute
dietary estimates were below the Agency's level of concern for all population
subgroups. The chronic (non-cancer) food exposures, even without applying
the washing reduction factor were below the level of concern for all population
subgroups. Drinking water risk estimates are based on surface and
groundwater screening models. The PRZM/EXAMS and the SCI-GROW
models were used on surface and ground water respectively. The drinking
water level of comparison (DWLOCs) for all population subgroups, are higher
than the surface and groundwater estimated drinking water concentration
(EDWC). Therefore, the chronic and acute drinking water exposures are not of
concern to the Agency.
Aggregate Risk
Under the Food Quality Protection Act of 1996, the Agency considers
contributions to risk from various exposure sources, specifically food, drinking
water, and non-occupational sources. Residential exposure and risk from the use
of ziram was limited to short-term exposure scenarios (dermal and inhalation)
because intermediate-term and chronic residential exposure to ziram from the
rabbit repellent and its use in paint are not expected to occur.
Occupational and Residential Exposure
Occupational exposure is of concern to EPA for workers handling ziram in
agricultural settings and commercial painters. Workers can be exposed during
mixing/loading and applying formulations containing ziram on agricultural,
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ornamental and commercial/industrial settings or re-entering the treated areas.
Risk for all of these potentially exposed populations is measured by a Margin of
Exposure (MOE), which determines how close the exposure comes to a No
Observable Adverse Effect Level (NOAEL). Generally, MOEs greater than 100
are not of concern.
Agricultural workers are primarily exposed to the dry flowable, liquid, and
wettable powder formulations. Both dermal and inhalation exposures are expected
to mixers, loaders, and applicators. The MOEs for agricultural workers ranged
from 8 to 170 while the target MOE was 100. The proposed mitigation is
expected to result in an acceptable level of risk for agricultural workers.
EPA's residential risk assessment indicates concern from outdoor use of
latex paints usually applied either with an airless sprayer or a brush. As a result,
dermal and inhalation exposures can result to homeowners. Only short-term
exposures were calculated because the Agency does not believe that homeowners
who apply paints with ziram will be exposed to the product for more than seven
days. Lowering the concentration of ziram in paints should result in acceptable
levels of risk. The Agency applied an uncertainty factor of 100 along with a
FQPA safety factor of 3x for a target MOE of 300. This additional factor was
applicable due to the quantitative evidence of increased susceptibility in the
developmental neurotoxicity study in rats. The combined dermal and inhalation
MOEs are 74 for the airless sprayer and 351 for the paint brush.
Tolerances
The tolerances for ziram and the other dithiocarbamates are enforced by a
common moiety method that determines carbon disulfide. The Agency is
recommending that the tolerances for ziram and all other dithiocarbamates be
changed to be expressed in terms of carbon disulfide. This recommended change
in tolerance expression allows harmonization of US tolerances with Codex
MRLs.
Tolerances (refer to 40 CFR § 180.116) or maximum residue limits are
summarized here. There are approximately 41 proposed revocations and 7
proposed new tolerances for ziram. The majority of the tolerances have remained
the same while some have decreased.
Environmental Environmental Fate
Assessment The major routes of dissipation of ziram are hydrolysis, photodegradation
and aerobic soil metabolism. Ziram's high susceptibility to degradation under
neutral and acidic environments reduces residues of ziram significantly in soil and
water, thereby minimizing the probability of prolonged exposure of terrestrial and
aquatic organisms to the chemical.
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Ecological Effects
EPA has identified ecological risks of concern from ziram use, particularly
to birds, mammals, and aquatic organisms. Ziram showed low acute toxicity for
mammals, is moderately toxic to avian species and highly toxic to aquatic
organisms. Exposure is determined by modeling residue concentrations on
foodstuffs for terrestrial animals and in water for aquatic organisms.
Risk Mitigation To mitigate risks to homeowners and commercial painters:
Reduce the concentration of ziram in latex paints from 3% to 1%.
To mitigate risks to agricultural workers:
• Upgrade personal protective equipment (PPE) for mixer/loaders of
liquid formulations from baseline to minimal.
• Require all wettable powder formulations to be packaged in water
soluble bags.
Require pilots to use planes with enclosed cockpits when applying
aerially.
• Cancel aerial applications on blackberries, blueberries, apples grown
East of the Rockies, cherries grown East of the Rockies, grapes
grown East of the Rockies, peaches grown East of the Rockies,
nectarines, pears, pecans, and tomatoes.
To mitigate ecological risks:
Reduce application rates on apples, cherries grown East of the
Rockies, pears, nectarines, and peaches grown West of the Rockies.
• Reduce the maximum numbers of applications to apricots, cherries,
nectarines, peaches, and pecans.
Additional Data EPA is requiring the following additional generic studies for Ziram to
Required confirm its regulatory assessments and conclusions:
• 830.7840 Additional water solubility studies
using column elution or shake flask
method
830.1750 Certification of Limits
• 830.1620 Description of Product on Process
830.7050 UV/Visible Absorption
• 835.4100 Aerobic soil metabolism with one
soil type near neutral pH
• 835.6100 Terrestrial field dissipation - upgrade
existing study or submit new study
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• 850.1300 Chronic toxicity study for freshwater
aquatic invertebrates
• 850.1350 Chronic toxicity study for
estuarine/marine aquatic
invertebrates
850.1400 Early Life Stage Freshwater Fish
850.1450 Early Life Stage Estuarine Fish
• 850.1500 Fish life cycle study for freshwater
and estuarine/marine fish
• 850.2300 Avian reproduction with mallard
duck
• 850.4225 Seedling Germination and Seedling
Emergence
850.4250 Vegetative Vigor
850.4400 Aquatic plant toxicity study (Tier 2)
• 860.1300 Nature of residue - plants, livestock
and processed food/feed
commodities
860.1500 Additional residue data required for
blackberries, blueberries, grapes, and
tomatoes
• 860.1540 Additional reduction of residue data
for orchard fruits, including washing
and processing studies (cooking data
suggested)
• 870.3465 90-day inhalation study in rats
• 870.5395 In-vitro Mammalian Cytogenetics
Tests
• 870.6300 Morphometric analyses of brain
tissues and statistical analyses of
neurobehavioral data in the
developmental neurotoxicity study
• 870.7485 Metabolism and pharmacokinetics
study in rats
The Agency also is requiring product-specific data including product
chemistry and acute toxicity studies, revised Confidential Statements of
Formula (CSFs), and revised labeling for reregistration.
Product Labeling All Ziram end-use products must comply with EPA's current pesticide
Changes Required product labeling requirements and with the following. For a comprehensive
list of labeling requirements, please see the Ziram RED document.
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Regulatory
Conclusion
For More
Information
The use of currently registered products containing Ziram in accordance
with approved labeling will not pose unreasonable risks or adverse effects to
humans or the environment. Therefore, all uses of these products are eligible
for reregistration.
Ziram products will be reregistered once the required product-specific
data, revised Confidential Statements of Formula, and revised labeling are
received and accepted by EPA.
EPA is requesting public comments on the Reregistration Eligibility
Decision (RED) document for Ziram during a 60-day time period, as
announced in a Notice of Availability published in the Federal Register. To
obtain a copy of the RED document or to submit written comments, please
contact the Pesticide Docket, Public Information and Records Integrity Branch,
Information Resources and Services Division (7502C), Office of Pesticide
Programs (OPP), US EPA, Washington, DC 20460, telephone
703-305-5805.
Electronic copies of the RED and this fact sheet are available on the
Internet. See http://www.epa.gov/pesticides/reregistration/status.htm.
Printed copies of the RED and fact sheet can be obtained from EPA's
National Service Center for Environmental Publications (EPA/NSCEP), PO
Box 42419, Cincinnati, OH 45242-2419, telephone 1-800-490-9198; fax 513-
489-8695.
Following the comment period, the Ziram RED document also will be
available from the National Technical Information Service (NTIS), 5285 Port
Royal Road, Springfield, VA 22161, telephone 1-800-553-6847, or 703-605-
6000.
For more information about EPA's pesticide reregistration program, the
Ziram RED, or reregistration of individual products containing Ziram, please
contact the Special Review and Reregistration Division (7508C), OPP, US
EPA, Washington, DC 20460, telephone 703-308-8000.
For information about the health effects of pesticides, or for assistance in
recognizing and managing pesticide poisoning symptoms, please contact the
National Pesticide Information Center (NPIC). Call toll-free 1-800-858-7378,
from 6:30 am to 4:30 pm Pacific Time, or 9:30 am to 7:30 pm Eastern
Standard Time, seven days a week. Their internet address is
http://npic.orst. edu.
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