United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-94-007
May 1994
R.E.D. FACTS
Pronamide
Pesticide
Reregistration
Use Profile
Regulatory
History
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 years ago 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. The Agency imposes
any regulatory controls that are needed to effectively manage each
pesticide's risks. EPA then reregisters pesticides that can be used without
posing unreasonable risks to human health or the environment.
When a pesticide is eligible for reregistration, EPA announces this and
explains why in a Reregistration Eligibility Decision (RED) document. This
fact sheet summarizes the information in the RED for pronamide, also
known by the trade name Kerb.
Pronamide is a selective, systemic, pre- and post-emergence herbicide
that acts by inhibiting plant cell division. It is used to control grasses and
broadleaf weeds in food and feed crops including lettuce (the largest use
site), endive, alfalfa, rhubarb, pome and stone fruits, artichokes, berries,
grapes and legumes, as well as on woody ornamentals, Christmas trees,
nursery stock, lawns, turf and fallow land. Formulations include a wettable
powder and a granular. Pronamide may be applied using ground spray
equipment, by soil incorporation or by aircraft.
Pronamide was first registered as a pesticide in the U.S. in 1972.
Between 1977-1979, EPA conducted a Special Review based on a study
indicating that pronamide caused cancer in mice. In concluding this review,
the Agency required: 1) restricted use classification for the 50% active
ingredient end-use products; 2) use of protective clothing during mixing and
application of the wettable powder formulations; 3) water-soluble packaging
for the wettable powders; and 4) lowering of the tolerance on lettuce from 2
ppm to 1 ppm, to reduce dietary exposure.
-------
EPA issued a Registration Standard for pronamide in April July 1986
(NTIS #PB87-103735), requiring additional generic data. A Data Call-in
issued in 1990 required additional product chemistry, residue chemistry,
plant protection and environmental fate data. The RED reflects EPA's
assessment of all data received, to date.
Currently, 18 products are registered which contain the active
ingredient (ai) pronamide. The 13 wettable powder products (each
containing 50% ai) are registered for food, feed and outdoor residential
uses. The 3 granular products (each containing up to 1% ai) are registered
only for use on lawns and turf. A formulation intermediate and a technical
grade manufacturing product also are registered.
Human Health Toxicity
Assessment In acute toxicity studies, pronamide technical is practically non-toxic
by the oral route, and has been placed in Toxicity Category IV (the lowest
of four categories) for this effect. It is slightly toxic by the dermal and
inhalation routes, and has been placed in Toxicity Category III for these
effects. In subchronic toxicity studies using rats, the liver, thyroid and
pituitary appear to be the target organs.
In chronic feeding studies, pronamide causes an increased incidence of
liver cancer in male mice, and benign testicular and thyroid tumors in rats.
EPA has classified pronamide as a Group B2 (probable human) carcinogen.
Pronamide appears to be a toxicant to the liver and several endocrine
organs including the thyroid, testes and pituitary. Pronamide is related to
the organochlorine class of chemicals, many of which disrupt the endocrine
system. Pronamide is not mutagenic.
Dietary Exposure
Some of the residue chemistry studies on pronamide were generated
by Craven Laboratories, which has been convicted of producing fraudulent
data. EPA has extrapolated information to draw satisfactory conclusions
about pronamide residues in food. However, several confirmatory residue
studies must be provided—for example, on alfalfa seed, dried winter peas
and early season use on artichokes.
Tolerances or maximum residue limits are established for residues of
pronamide in or on a number of food and feed crops, meat and milk (see 40
CFR 180.317(a)). Crop group tolerances must be proposed for residues
in/on forage and hay of the non-grass animal feeds group, and for the stone
fruits group. The tolerance for endive must be reduced from 2.0 ppm to
1.0 ppm. Certain animal organ tolerances must be raised from 0.2 ppm to
0.4 ppm, due to improved efficiency of enforcement residue detection
methods.
-------
Based on the anticipated residue contributions of red meat and milk
(which contribute the most to anticipated residues in the diet) and reassessed
tolerances, EPA estimates that the overall U.S. population is exposed to
0.04% of the Reference Dose (RfD) or amount believed not to cause
adverse effects if consumed daily over a 70-year lifetime. Dietary exposure
to pronamide is associated with an estimated upper bound cancer risk of 5 x
10-7, or five extra incidences of cancer per 10,000,000. This assessment
still overestimates the actual degree of risk, which is likely to be less.
Occupational and Residential Exposure
Pesticide handlers (mixers, loaders and applicators) may be exposed to
pronamide sprays and dusts via skin and inhalation during ground boom,
aerial and hand-spray applications. The major route of exposure is the
dermal route, and exposure is estimated for use of the wettable powder
formulation in water-soluble pouches.
Workers and homeowners also may be dermally exposed post-
application to pronamide residues on treated foliage and soil. To reduce
exposure and risk, EPA is imposing a restricted entry interval following
commercial food, feed and turf uses. However, the Agency is unable to
estimate risks associated with use of pronamide on residential lawns, and
cannot impose a reentry interval for residential situations. Therefore, EPA
is unable to make a reregistration eligibility decision about pronamide use
on residential lawns, pending the results of several exposure studies.
Similarly, post-application reentry data are required for pronamide use
on lettuce because of the potential for significant hand contact.
Human Risk Assessment
Pronamide is of relatively low acute toxicity, but has been
demonstrated to cause liver cancer in male mice and is classified as a B2
"probable" human carcinogen. People may be exposed to residues of
pronamide in a number of food crops, meat and milk. However, chronic
exposure to pronamide in the diet is at a very low level (only a small
fraction of the RfD), and is not a cause for concern at this time.
There is a concern for cancer associated with lifetime exposure of
mixers/loaders/applicators and homeowners to pronamide. The combined
risk for mixer/loader/applicators wearing personal protective equipment
(PPE) is estimated to be 3 x 10-5. However, this estimate is conservative
and actual risk is likely to be lower.
-------
Environmental
Assessment
Additional Data
Required
Environmental Fate
Pronamide is stable to hydrolysis, and to photolysis in water and on
soil. It is very persistent in soil under aerobic conditions, and even more
persistent under anaerobic conditions (with an estimated half-life greater
than 13 months). Pronamide has a relatively low vapor pressure and is
relatively mobile in soil. Leaching appears to be its major route of
dissipation.
A chemical with these properties is expected to be persistent and
mobile in the field. Therefore, a study generated by Craven Laboratories
which suggests that pronamide is neither persistent nor mobile must be
replaced by a new field dissipation study.
Ecological Effects
Pronamide is practically nontoxic to birds and mammals on an acute
basis. It is slightly toxic to freshwater fish and moderately toxic to
freshwater invertebrates. Although toxicity to aquatic organisms is not
anticipated, confirmatory estuarine studies are required. Pronamide is toxic
to green algae. Testing on four other aquatic plants is required, therefore,
to assess effects on the aquatic habitat and endangered aquatic plant species.
Ecological Effects Risk Assessment
Use of pronamide as directed by product labeling will have minimal
adverse acute effects on insects, birds and mammals. However, chronic
risk to aquatic invertebrates is possible, due to pronamide's persistence in
water. EPA is requiring an aquatic invertebrate life cycle study to assess
this potential risk. Testing on four additional aquatic plant species is
required, as mentioned above. Risks to non-target terrestrial plants also will
be further explored.
Regarding endangered species, pronamide may not adversely effect
endangered birds or aquatic invertebrates, but risk to aquatic plants is
uncertain. Terrestrial plants may be adversely affected by pronamide
applied at maximum label rates. EPA may require additional labeling and
use modifications when implementing the Endangered Species Protection
Program.
EPA is requiring the following additional generic data for pronamide
to confirm its regulatory assessments and conclusions:
Product Identity
Aquatic Invertebrate Life Cycle
Estuarine and Marine Organisms (Mollusc and Shrimp)
Terrestrial Field Dissipation
Field Rotational Crop
-------
Droplet Size Spectrum and Drift Field Evaluation
Foliar Dislodgeable Dissipation
Dermal Passive Dosimetry
Estimation of Dermal/Inhalation Exposure at
Outdoor Sites
Residue Analytical Method
Storage Stability
Magnitude of Residue
Processed Food
The following studies which are not part of the target data base also are
required:
Seed Germination/Seedling Emergence
Aquatic Plant Growth
The following studies are required to support use of products on residential
lawn and turf:
Foliar Dislodgeable Dissipation
Dermal Passive Dosimetry
To support the late season use of pronamide on artichokes, registrants must
delete this use from their product labels or submit the following study:
Magnitude of Residue
The Agency also is requiring product-specific data including product
chemistry and acute dermal toxicity studies, and revised labeling for
reregistration.
Product Labeling All pronamide end-use products must comply with EPA's current
Changes Required pesticide product labeling requirements, and the following:
Worker Protection Standard (WPS) - All pronamide products within the
scope of the Worker Protection Standard (WPS) for Agricultural Pesticides
(see PR Notice 93-7) must, within the timeframes listed in PR Notices 93-7
and 93-11, revise their labeling to be consistent with the WPS, as directed in
those notices and the requirements of the RED.
Entry Restrictions
Uses Within the Scope of the WPS - A 24-hour restricted entry
interval (REI) is required on all end-use products, except those intended
primarily for home use. The PPE for early entry must be that required for
applicators of pronamide except no apron or respirator is required.
• Labels of Sole AI Products - Revise to adopt these entry
restrictions. Remove any conflicting entry restrictions on current
labeling.
-------
• Labels of Multiple-AI Products - Must bear the more protective of
either the entry restrictions set forth here, or those on current
labeling.
Uses Not Within the Scope of the WPS - Do not add any entry
restrictions, but retain any on current labeling.
Personal Protective Equipment (PPE) Requirements
Uses on Products NOT Primarily Intended for Home Use The PPE
requirement for pesticide handlers on all end-use products is:
"Applicators and other handlers must wear:
—Coveralls over short sleeved-shirt and short pants
—Chemical-resistant or waterproof gloves
—Chemical-resistant footwear plus socks
—Chemical-resistant headgear for overhead exposure
—Chemical-resistant apron when cleaning equipment, mixing or
loading."
Pronamide products must bear these PPE requirements or those on current
labeling, which ever is more protective.
Lawn and Turf Uses - If a registrant chooses to support the residential
lawn uses only, he/she must add the following exclusionary statement on the
front panel of the product label near the product name, or near the
beginning of the Directions for Use section:
"Not for use on turf being grown for sale or other commercial use as
sod, or for commercial seed production, or for research purposes."
If the registrant does not support the residential lawn uses, he/she must
amend the product label to delete lawn and turf uses.
Fish and Wildlife Hazard - Labels must bear the following statement in the
Precautionary Statements section under the subheading Environmental
Hazards:
"Do not apply directly to water, or to areas where surface water is
present or to intertidal areas below the mean high water mark. Do not
contaminate water when disposing of equipment washwaters."
Restricted Use Pesticide Classification - The wettable powder products
must maintain the Restricted Use Pesticide classification imposed at the
conclusion of the Special Review.
Regulatory The use of all currently registered pesticide products containing
Conclusion pronamide in accordance with approved labeling, except residential lawn
and turf uses and late season use on artichokes, will not pose unreasonable
risks or adverse effects to humans; however, they may pose adverse effects
to terrestrial plants and perhaps to aquatic plants. Products containing
pronamide for all uses, except broadcast application on residential lawns
-------
and turf, and the late season use on artichokes, are eligible for
reregistration.
EPA has insufficient data at this time to make a reregistration
eligibility decision regarding the use of pronamide on residential lawns and
turf, or the late season use on artichokes. An eligibility decision cannot be
made for broadcast application to residential lawns and turf until post-
application/reentry exposure data are submitted and evaluated. A decision
cannot be made for late season use on artichokes until residue data are
submitted and evaluated.
Products that are eligible will be reregistered once the required
confirmatory generic data, product specific data and revised labeling are
received and accepted by EPA.
For More EPA is requesting public comments on the Reregistration Eligibility
Information Decision (RED) document for pronamide 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 Response and Program Resources
Branch, Field Operations Division (7506C), Office of Pesticide Programs
(OPP), US EPA, Washington, DC 20460, telephone 703-305-5805.
Following the comment period, the pronamide RED document will be
available from the National Technical Information Service (NTIS), 5285
Port Royal Road, Springfield, VA 22161, telephone 703-487-4650.
For more information about EPA's pesticide reregistration program,
the pronamide RED, or reregistration of individual products containing
pronamide, please contact the Special Review and Reregistration Division
(7508W), 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 Pesticides Telecommunications Network (NPTN). Call toll-
free 1-800-858-7378, from 8:00 am to 6:00 pm Central Time, Monday
through Friday.
------- |