United States
Environmental Protection
Agency
Prevention, Pesticides
And Toxic Substances
(7508W)
EPA-738-F-95-005
January 1995
R.E.D. FACTS
Fosamine ammonium
Pesticide
Reregistration
Use Profile
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 document for
reregistration case 2355, fosamine ammonium.
Fosamine ammonium is an herbicide/plant growth regulator used to
control brush and herbaceous plants on noncropland. It is applied to
nonagricultural rights-of-way (e.g. highways, railroads, and utilities),
industrial sites, and fencerows.
Fosamine ammonium is formulated in end use products as a water
soluble liquid. It is applied once per year from Spring to early Fall, by
aircraft, backpack and handwands. After application, the brush control
effects of the pesticide are achieved by inhibiting bud growth the following
year.
Use practice limitations prohibit fosamine ammonium from being used
on croplands or in irrigation systems. It may not be applied directly to
water, or areas where surface water is present, including intertidal areas.
Soils treated with this herbicide cannot be converted to food/feed croplands
within one year of treatment.
Fosamine ammonium is not registered for use in California and
Arizona.
Regulatory
Fosamine ammonium was first registered as a pesticide in the U.S. in
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History
Human Health
Assessment
1975. It was registered for non-cropland (non-food use) areas such as
railroads, pipelines, utility and highway rights-of way, reforestation areas,
drainage ditch banks, storage areas, industrial plants, and other similar sites.
However, this product was voluntarily cancelled on June 22, 1994.
A second product was registered in 1980 with the same uses as the
original product except for reforestation uses. This product currently is
marketed under two trade names. The registrant requested to voluntarily
cancel direct applications to water, ditch banks, and to other sites which are
adjacent to and surrounding domestic water supply reservoirs, supply
streams, lakes and ponds. The Agency is processing this request, which
involves publishing a Notice of Intent to delete these uses in the Federal
Register. Because there are no other current registrants and there are
outstanding environmental data requirements to support continued
registration of these uses, the Agency expects that these sites will be deleted
from the label by early 1995.
Toxicity
Fosamine ammonium is classified as Toxicity Category II for acute
dermal studies in mammalian species. This classification represents the
second most severe level of acute toxicity for studies using laboratory
animals (Toxicity Category I is the highest). Fosamine ammonium is very
mildly toxic for acute oral and acute inhalation (Toxicity Category IV), and
is not a dermal sensitizer.
In one subchronic oral study, the laboratory animals given the highest
dose of fosamine ammonium exhibited some statistically significant effects,
including effects to the kidneys, bladder and decreases in body weight.
There were no subchronic neurotoxic effects of fosamine ammonium at any
dose level.
Fosamine ammonium displayed some mutagenic potential in one in
vitro test for chromosome aberrations, while four other tests were negative
for mutagenic potential.
Dietary Exposure
Since there are no registered food uses for fosamine ammonium, no
dietary exposure is expected.
Occupational and Residential Exposure
Based on current use patterns, workers may be exposed to fosamine
ammonium during and after application of the pesticide. Worker exposure
estimates are based on the assumption that workers wear long pants, long
sleeved shirt, shoes, and no gloves, except for workers using backpacks
(who are assumed to wear chemical resistant gloves). The primary route of
exposure to fosamine ammonium is expected to be dermal. Another
potential route of exposure is through inhalation. However, based on the
exposure assumptions, the potential for inhalation exposure is negligible.
Human Risk Assessment
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Environmental
Assessment
Since no food uses are registered, fosamine ammonium poses no
human dietary risks. Regarding acute toxicity, fosamine ammonium falls in
Toxicity Category II for acute dermal exposure. However, the mild skin
effects observed with this chemical do not trigger any significant
toxicological concerns. The herbicide/plant growth regulator is of low
toxicity by the oral and inhalation routes. Based on the mixed results of
studies suggesting mutagenetic potential, the Agency is requiring additional
testing with germ cells as a confirmatory study.
Based on the current use pattern of fosamine ammonium, the
estimated exposure to workers, which is likely to reflect a worse-case
scenario, does not pose a serious threat to workers. However, there are no
known significant acute or chronic toxicological endpoints that warrant the
establishment of risk mitigation measures or minimum personal protective
equipment (PPE) requirements to protect handlers of the pesticide. Clothing
as described in the exposure assessment will provide adequate protection to
handlers. In addition, EPA is requiring application restrictions and user
safety recommendations on end-use product labeling.
Environmental Fate
Fosamine ammonium is not very persistent under aerobic or anaerobic
conditions and degrades rapidly in most soils. Dissipation of fosamine
ammonium is dependent on rapid, microbial mediated degradation. Thus,
in field studies fosamine ammonium was found to be highly soluble in water
and is mobile in various soils. However, in the sterile conditions of the
laboratory, fosamine ammonium is stable to hydrolysis. Although fosamine
ammonium is a mobile compound, there is little evidence that leaching is a
major route of dissipation. Data on the residues of fosamine ammonium
indicate they are also relatively mobile.
Fosamine ammonium may be found in surface waters with low
microbiological activities or long hydrological residence times.
Exposure of fosamine ammonium to non-target aquatic plants can
result from spray drift from treated areas, surface runoff, or wind blown
soil particles. However, no acute risk quotients exceed the level of concern,
so no acute effects to aquatic plants are expected from the normal use of
fosamine ammonium.
The risk to terrestrial non-target plants cannot be determined until
Tier I and Tier II data requirements have been fulfilled. Results of the most
sensitive terrestrial plant species tested are needed in order to conduct an
acute risk assessment.
Any movement of fosamine ammonium from the treatment site via
spray drift, surface runoff, or wind blown soil particles can adversely affect
non-target and endangered/threatened plants. Direct application of rights-
of-way are a special concern, because large numbers of endangered plants
grow in rights-of-way areas. Thus applications of fosamine ammonium at
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the registered rates may pose a significant risk to endangered plant species
inhabiting treated rights-of-way.
EPA has been working with the U.S. Fish and Wildlife Service and
other federal and state agencies to develop a program to avoid jeopardizing
endangered species. The Endangered Species Program is expected to be
final soon. Further limitations on the use of fosamine ammonium may be
imposed at that time.
Further droplet size spectrum and field drift studies are due to the
Agency at the end of June 1995 as part of the spray drift data requirements
to be submitted by the Spray Drift Task Force. If the new data suggest
substantially different drift potential, the Agency will reassess its impact on
the associated environmental risks at that time.
Ecological Effects
Exposure to non-target aquatic organisms can result from spray drift
and runoff from treated areas. However, acute effects to freshwater fish
and aquatic invertebrates are not expected from the normal use of fosamine
ammonium. Fosamine ammonium is practically nontoxic to coldwater and
warmwater fish, and does not appear to bioaccumulate in fish. However, a
nine percent fish mortality was observed in the accumulation in fish study.
Fosamine ammonium is practically nontoxic to freshwater invertebrates and
to estuarine species.
Fosamine ammonium is practically nontoxic to honey bees, which are
used to assess the effects on non-target insects.
Fosamine ammonium is practically nontoxic to avian species on an
acute oral and a subacute dietary basis. Mixed results were found in the
avian reproductive studies. In one mallard duck study, there was some
indication of chronic reproductive effects. However, in another avian
reproductive study, using the bob white quail as the test organism, there
were no reproductive effects at any dose level.
Fosamine ammonium is practically nontoxic to small mammalian
species. Acute oral and subacute dietary risks to non-endangered and
endangered non-target mammals are not expected to result from current
label uses.
Ecological Effects Risk Assessment
Based on the data, fosamine ammonium dissipation is predominantly
dependent on rapid microbial-mediated degradation. It is also mobile in
mineral soils. However, fosamine ammonium should not pose a threat to
groundwater or surface waters because it rapidly degrades in aerobic and
anaerobic environments. There are no Maximum Concentration Levels
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Additional Data
Required
Product Labeling
Changes Required
(MCLs) or drinking water health advisories for fosamine ammonium or its
degradates.
The health and environmental data on fosamine ammonium indicate a
low level of toxicity of this pesticide. However, the inconclusive results in
the avian reproductive studies have led the Agency to require a new mallard
duck reproduction study on a confirmatory basis. In addition, risk
mitigation measures are required to reduce the potential for avian
reproductive effects.
EPA is requiring the following additional generic data for fosamine
ammonium to confirm its regulatory assessments and conclusions:
Certification of limits (62-2), Avian reproduction, mallards (71-4b), In-vivo
cytogenetics (84-2a), Droplet size spectrum and field drift data (201-1, 202-
1), Method validation for worker exposure (231, 232), Terrestrial plant
(122-1, 123-1), and Aerobic aquatic (164-2, 162-4) if aquatic sites are not
deleted.
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.
All fosamine ammonium end-use products must comply with EPA's
current pesticide product labeling requirements, and with the following:
a) Within the Environmental Hazards section of the Precautionary Statement
of the label:
"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 or
rinsate."
b) To reduce environmental loading and potential exposure to non-target
species, the product label must include language to limit use as outlined
below:
i) the end-use product can be applied only once annually during the
period after spring growth has hardened to the development of fall
coloration in deciduous species, and
ii) the maximum application rate for low shrubs/brush is 16 Ib a.i./A,
and for tall dense woody species with very heavy foliage can be 24 Ib
a.i./A.
c) The end-use product labels cannot include directions for applications to
aquatic sites. The current, sole registrant has submitted an application for
amended registration to delete these uses from its product registration.
Future submissions of appropriate data to support registration for these uses
will be considered by the Agency.
d) The Agency is requiring the following labelling statements to be located
on all end-use products containing fosamine ammonium:
Application Restrictions:
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Regulatory
Conclusion
For More
Information
"Do not apply this product in a way that will contact workers or
other persons, either directly or through drift. Only protected
handlers may be in the area during applications."
Entry Restrictions
The Agency is establishing the following entry restrictions for
the occupational uses of fosamine ammonium end-use products:
For liquid applications:
"Do not enter or allow others to enter the treated area until
sprays have dried."
Other Labelling Requirements:
User Safety Recommendations:
"Users should wash hands before eating, drinking, chewing
gum, using tobacco, or using the toilet."
"Users should remove clothing immediately if pesticide gets
inside. Then wash thoroughly and put on clean clothing."
"Users should remove clothing immediately after handling this
product. If gloves are worn, wash the outside of gloves before
removing. As soon as possible, wash thoroughly and change
into clean clothing."
These statements must be included on the labels, as they are
appropriate, after product-specific PPE requirements are set by the Agency.
Although it is not required under the current labeling, it is assumed that the
workers wear long pants, long sleeved shirts, shoes, and socks.
The use of currently registered products containing fosamine
ammonium in accordance with approved labeling, except use in aquatic
sites, will not pose unreasonable risks or adverse effects to humans or the
environment. The registrant has voluntarily requested cancellation of the
aquatic uses. The Agency is not including the aquatic uses in its eligibility
decision, because of the inadequate environmental data and the impending
deletion of those uses from all current registrations. Therefore, all uses of
fosamine ammonium products, other than application to aquatic sites, are
considered eligible for re registration.
Fosamine ammonium 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 fosamine ammonium 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
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Pesticide Programs (OPP), US EPA, Washington, DC 20460, telephone
703-305-5805.
Electronic copies of the RED and this fact sheet can be downloaded
from the Pesticide Special Review and Reregistration Information System at
703-308-7224. They also are available on the Internet on EPA's gopher
server, GOPHER.EPA. GOV, or using ftp on FTP.EPA.GOV, or using
WWW (World Wide Web) on WWW.EPA.GOV.
Printed copies of the RED and fact sheet can be obtained from EPA's
National Center for Environmental Publications and Information
(EPA/NCEPI), PO Box 42419, Cincinnati, OH 45242-0419, telephone
513-489-8190, fax 513-489-8695.
Following the comment period, the fosamine ammonium RED
document also 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 fosamine ammonium RED, or reregistration of individual products
containing fosamine ammonium, 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, between 8:00 am and 6:00 pm Central Time, Monday
through Friday.
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