United States
Environmental Protection
Agency
Office of Prevention, Pesticides
And Toxic Substances September
(H-7508W)
EPA-738-F-93-015
1993
R.E.D. FACTS
Pesticide
Reregistration
Inorganic Halides
All pesticides sold or used 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 undue hazards 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 sodium bromide and
sodium chloride, which made up the reregistration case called Inorganic
Halides.
Use Profile
Sodium bromide is used as a microbiocide to control algae, bacteria
and fungi in pasteurizer and cannery cooling water recirculation systems,
pulp and paper mill water systems, and ornamental ponds and aquaria. It
also is an active ingredient in pesticide products used to repel moths from
clothing, and fleas from pets and their sleeping quarters. Products are
formulated as liquid or solid soluble concentrates, tablets or granules.
Sodium bromide has been used for many years in medicine as a sedative.
Sodium chloride is one of two active ingredients in a disenfectant used
to treat feeding and watering appliances, equipment and premises in poultry
operations. Sodium chloride is also the sole active ingredient impregnated
into polyethylene whcih is placed around gardens as a barrier to slugs and
snails.
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Regulatory Sodium bromide was first registered as a pesticide in the U.S. in
History 1975. Currently, 32 pesticide products contain the active ingredient sodium
bromide.
Products containing sodium chloride were first registered as pesticides
in the U.S. in 1954. At present, 2 pesticide products contain sodium
chloride as an active ingredient.
Human Health
Assessment
Toxicity
Sodium bromide is of low acute oral and moderate dermal toxicity,
and has been placed in Toxicity Category III for these effects. (Category I
indicates the highest and Category IV the lowest degree of acute toxicity.) It
causes mild eye and skin irritation, and for those effects it has been placed
in Toxicity Category IV.
The human health effects of bromides following oral exposure are
well known. The bromine salts have a depressant effect on the nervous
system when administered at levels of 1 to 2 grams per day. This effect is
slowly reversed when treatment is stopped.
Sodium chloride is of low acute oral toxicity and causes moderate eye
irritation; it has been placed in Toxicity Category III for these effects. It
causes mild skin irritation and for this effect has been placed in Toxicity
Category IV
Sodium chloride, known as salt, sea salt and table salt, is abundant in
nature. It is used primarily to season or preserve food and is consumed by
people daily, especially in commercially prepared and preserved foods.
Consumption of more than the minimum daily requirement of salt may
contribute to high blood pressure in some populations.
Dietary Exposure
Dietary exposure to sodium bromide and sodium chloride is not
expected to occur as a result of their pesticidal uses. None of the currently
registered pesticide products involve food or feed uses, and no tolerances
(residue limits in food) are established for these pesticides as a result of
these uses.
Occupational and Residential Exposure
The potential for mixer/loader/applicator exposure exists primarily
from fogging- or misting-type applications of the disenfectant containing
sodium chloride, and from handling the liquid formulation of sodium
bromide. These exposures are considered minimal or low, however, and
are do not pose human toxicity concerns.
Human Risk Assessment
The risk from occupational exposure to sodium bromide and sodium
chloride is considered to be minimal. Their toxicity (or lack of toxicity) in
humans is well documented. No additional hazard or exposure data are
required for reregistration eligibility. Based on the low toxicity, minimal
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Environmental
Assessment
exposure risk and limited pesticidal uses of sodium bromide and sodium
chloride, the risks to humans are considered negligible.
EPA did not perform an environmental assessment of sodium
chloride. The registered uses result in insignificant exposure to the
environment. Sodium chloride occurs abundantly in the natural
environment. It is a component of seawater, and is in the diets of most
terrestrial animals. Although it can be toxic in large amounts, especially to
freshwater aquatic organisms, the use of sodium chloride as registered will
not result in any significant exposure to non-target organisms in the
environment.
The following assessment addresses sodium bromide only.
Environmental Fate
Sodium bromide itself has no pesticidal activity. It dissociates in
water to sodium and bromide ions. Activators such as chlorine and sodium
hypochlorite react with the bromine ion to form hypobromous acid, which is
the actual pesticide. The chemistry of hypobromous acid has been well
documented in the literature.
When used in cooling towers and water systems, sodium bromide
effectively controls algae, bacteria and fungal slime. It is injected into the
service water with or after an activator (either chlorine gas or sodium
hypochlorite), producing the active disinfectant hypobromous acid, an
effective microbiological control treatment. As hypobromous acid passes
through a heat exchange unit, it is converted back to bromide ion and water.
Discharge of hypobromous acid is limited by the National Pollutant
Discharge Elimination System (NPDES) permit program.
The Agency conducted a Tier Ic Estimated Environmental
Concentration (EEC) model for hypobromous acid, to demonstrate the
maximum concentration likely to occur immediately downstream from an
industrial (point source) discharge site. EECs were calculated for both
"high exposure case" and "typical" sites. The worst case EEC for all use
sites tested was 450 parts per billion (ppb), and the typical sites ranged from
0.38 to 0.75 ppb. These estimated concentrations are discussed in relation
to ecological effects, below.
Ecological Effects
Sodium bromide is practically non-toxic to upland game birds and
waterfowl on both an acute oral and a dietary basis. However, sodium
bromide as hypobromous acid is highly toxic to freshwater fish, aquatic
invertebrates and estuarine and marine organisms.
In two aquatic residue monitoring studies conducted at powerplants on
the Potomac River in Maryland, bromine as hypobromous acid measured at
the point of discharge exceeded the levels of concern for estuarine species in
one study, and for all aquatic species in the second study. Significant
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Additional Data
Required
Product Labeling
Changes Required
residue levels were detected 80 meters downstream; residues were no longer
detectable between 80 and 130 meters downstream.
Ecological Effects Risk Assessment
As discussed earlier, EPA conducted a Tier Ic EEC screening model
for hypobromous acid to estimate the maximum concentration that occurs
immediately downstream from an industrial point source discharge site.
The results for the high exposure case are comparable to the amounts
detected in the two Potomac River aquatic residue studies, one of which
showed high concentrations of hypobromous acid as far downstream as 80
meters. Based on these studies, the Agency presumes risk to freshwater and
estuarine fish and invertebrates at the point of discharge and downstream to
80 meters.
However, the modeling results for "typical" sites are well below the
levels of concern for fish and invertebrates. These results indicate that
sodium bromide can be used at typical sites without impact most of the time.
Since the discharge of hypobromous acid is limited by the NPDES permit
program administered by EPA's Office of Water, the Agency will be able to
control the discharge of hypobromous acid on a site-by-site basis so that
toxic levels are avoided.
Based on this modeling, EPA also presumes a risk to endangered
freshwater and estuarine/marine organisms in "worst case" situations.
However, "typical" discharge levels are below those of concern for
endangered species.
EPA has sufficient generic data to support reregistration of all
products containing sodium bromide. Due to the nature of the pesticide and
the amount of information available in the public literature, EPA required
no generic data for reregistration of sodium chloride.
EPA is requiring product-specific data including acute toxicology,
chemistry and efficacy studies, as well as revised Confidential Statements of
Formula and revised labeling, for reregistration of pesticide products
containing sodium bromide and sodium chloride.
The labels of all registered pesticide products containing sodium bromide
and sodium chloride must comply with EPA's current pesticide labeling
requirements. In addition, all products containing sodium bromide must
contain the following effluent discharge statement:
"This product is toxic to fish and aquatic invertebrates. Do not
discharge effluent containing this product into lakes, streams, ponds,
estuaries, oceans or other water unless in accordance with the
requirements of a National Pollution Discharge Elimination System
(NPDES) permit and the permitting authority has been notified in
writing prior to discharge. Do not discharge effluent containing this
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Regulatory
Conclusion
For More
Information
product to sewer systems without previously notifying the local
sewage treatment plant authority. For guidance contact your State
Water Board or Regional Office of EPA."
The use of currently registered pesticide products containing sodium
bromide and sodium chloride as labeled and specified in the RED document
will not pose unreasonable risks or adverse effects to humans or the
environment. Therefore, all uses of these products are eligible for
reregistration.
These products will be reregistered once the product-specific data,
revised (if necessary) 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 the Inorganic Halides (sodium
bromide and sodium chloride) 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 (H-7506C), Office of Pesticide Programs (OPP), US
EPA, Washington, DC 20460, telephone 703-305-5805.
Following the comment period, the Inorganic Halides 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 Inorganic Halides RED, or reregistration of individual products
containing sodium bromide or sodium chloride, please contact the Special
Review and Reregistration Division (H-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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