United States
Environmental Protection
Agency
Office of Prevention, Pesticides
And Toxic Substances September 1992
(H-7508W)
<&EPA Reregistration
Eligibility Document
(RED)
5WRS-93-229
Zinc Salts
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ZINC SALTS REREGISTRATION ELIGIBILITY TEAM
Office of Pesticide Programs:
Biological and Economic Analysis Division
Jim Saulmon Biological Analysis Branch
Eric Maurer Economic Analysis Branch
Environmental Fate and Effects Division
Katherine Valente Ecological Effects Branch
Sylvia Termes Environmental Fate and Groundwater Branch
Jean Holmes Science Analysis and Coordination Staff
Health Effects Division
Linda Kutney
Pat McLaughlin
Jim Yowell
Registration Division
Sami Malak
Olga Odiott
Mary Matzer
Joanne Miller
Chemical Coordination Branch
Toxicology Branch II
Occupational and Residential Exposure Branch
Registration Support Branch
Registration Support branch
Herbicide Fungicide Branch
Herbicide Fungicide Branch
Special Review and Reregistration Division
Bruce Sidwell Accelerated Reregistration Branch
Mark Wilhite Accelerated Reregistration Branch
Policy and Special Projects Staff
Jean Frane Analyst
Office of General Counsel
Jim Curtin Attorney
Office of Compliance Monitoring
Beverly Updike
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TABLE OF CONTENTS
EXECUTIVE SUMMARY
I. INTRODUCTION
n. CASE OVERVIEW
A. CHEMICAL OVERVIEW
B. USE PROFILE
C. REGULATORY HISTORY
m. SCIENCE ASSESSMENT OF ZINC SALTS
A. PRODUCT CHEMISTRY ASSESSMENT
B. HUMAN HEALTH ASSESSMENT
1. Hazard Assessment
a. Acute and Subchronic Toxicity
b. Chronic Toxicity and Carcinogenicity
c. Other Toxicological Effects
2. Exposure Assessment
a. Dietary Exposure
b. Occupational and Residential Exposure
C.
3. Risk Assessment
ENVIRONMENTAL ASSESSMENT
a. Environmental Fate and Transport
b. Environmental Fate Assessment
2. Ecological Effects
a. Ecological Hazard
b. Ecological Effects Risk Assessment
3
4
5
6
6
6
8
9
10
11
11
11
12
12
13
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IV. RISK MANAGEMENT AM) REREGISTRATION DECISION FOR ZINC
SALTS
A. DETERMINATION OF ELIGIBILITY 14
B. REGULATORY POSITION 15
V. ACTIONS REQUIRED BY REGISTRANTS
A. ADDITIONAL GENERIC DATA REQUIREMENTS 15
B. PRODUCT SPECIFIC DATA REQUIREMENTS 15
C. LABELING REQUIREMENTS 16
VI. APPENDICES
APPENDIX A - Use Patterns Subject to Reregistration
APPENDIX B - Table of the Generic Data Requirements and Studies Used to Make
the Reregistration Decision
APPENDIX C - Citations Considered to be Part of the Data Base Supporting the
Reregistration of Zinc Salts
APPENDIX D - List of Available Related Documents
APPENDIX E - Pesticide Reregistration Handbook
APPENDIX F - Generic Data Call-In
Attachment A - Chemical Status Sheet
Attachment B - Generic DCI Response Forms (Form A) plus Instructions
Attachment C - Requirements Status and Registrants' Response Forms
(Form B) plus Instructions
Attachment D - List of all Registrant(s) sent this DCI
Attachment E - Cost Share/Data Compensation Forms
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APPENDIX G - Product Specific Data Call-In
Attachment A - Chemical Status Sheet
Attachment B - Product Specific DCI Response Forms (Form A) plus
Instructions
Attachment C - Requirements Status and Registrants' Response Forms
(Form B) plus Instructions
Attachment D - EPA Grouping of End Use Products for meeting Acute
Toxicology Data Requirements.
Attachment E - EPA Acceptance Criteria
Attachment F - List of all Registrant(s) sent this DCI
Attachment G - Cost Share/Data Compensation Forms
in
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GLOSSARY OF TERMS AND ABBREVIATES
a.i. Active Ingredient
CAS Chemical Abstracts Service
CSF Confidential Statement of Formula
EEC Estimated Environmental Concentration. The estimated pesticide concentration
in an environment, such as a terrestrial ecosystem.
EP End-Use Product
EPA U.S. Environmental Protection Agency
FIFRA Federal Insecticide, Fungicide, and Rodenticide Act
FFDCA Federal Food, Drug, and Cosmetic Act
HDT Highest Dose Tested
LQo Median Lethal Concentration. A statistically derived concentration of a
substance that can be expected to cause death in 50% of test animals. It is
usually expressed as the weight of substance per weight or volume of water or
feed, e.g., mg/1 or ppm.
LDj0 Median Lethal Dose. A statistically derived single dose that can be expected
to cause death in 50% of the test animals when administered by the route
indicated (oral, dermal, inhalation). It is expressed as a weight of substance
per unit weight of animal, e.g., mg/kg.
Ldlo Lethal Dose-low. Lowest Dose at which lethality occurs
LEL Lowest Effect Level
MP Manufacturing-Use Product
MRID Master Record Identification (number). EPA's system of recording and
tracking studies submitted.
N/A Not Applicable
NPDES National Pollutant Discharge Elimination System.
iv
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GLOSSARY OF TERMS AND ABBREVIATIONS (cont.)
NOEL No Observed Effect Level
OPP Office of Pesticide Programs
ppm Parts Per Million
TD Toxic Dose. The dose at which a substance produces a toxic effect
TC Toxic Concentration, The dose at which a substance produces a toxic effect
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EXECUTIVE SUMMARY
The active ingredients covered in this document include zinc chloride, zinc oxide and
zinc sulfate monohydrate (hereafter referred to as zinc sulfate). Products containing these
active ingredients are used as herbicides, fungicides and bacteriostats for the control of moss,
mildew and fungi on structures and adjacent outdoor areas, in carpet, and in pressure treated
lumber. This Reregistration Eligibility Document (RED) addresses the eligibility for
reregistration of products containing these active ingredients for the above mentioned use
sites only.
Formulations for zinc oxide include an end use industrial preservative for
incorporation into nylon carpet fibers to inhibit bacterial and fungal spoilage, a powder for
control of moss growth on walkways, patios and ornamental lawn use; a metal strip attached
to roofs where it releases soluble oxide which inhibits moss growth; and an ingredient for
pressure treatment of lumber. Zinc chloride is formulated as a solution or soluble concentrate
for application to walkways and patios for control of moss. Zinc sulfate is formulated as a
soluble concentrate also for control of moss on and around buildings.
. The U.S. EPA (hereafter referred to as "the Agency") has determined that the uses of
these three active ingredients as they are currently registered will not cause unreasonable risk
to humans or the environment. Therefore the zinc salts are eligible for reregistration. The
Agency is requiring additional studies on physical chemistry as confirmatory data and for
purposes of labeling to complete the generic data base.
Before reregistering the products containing these zinc salts, the Agency is requiring
that product specific data and revised labeling be submitted within eight months of the
issuance of this document. These data include product chemistry and acute toxicology
testing. After reviewing these data and any revised labels and finding them acceptable, the
Agency will reregister a product based on whether or not that product meets the requirements
in Section 3(c)(5) of FIFRA.
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r.
INTRODUCTION
In 1988, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) was
amended to accelerate the reregistration of products with active ingredients registered prior to
November 1, 1984. The amended Act provides a schedule for the reregistration process to
be completed in nine years. There are five phases to the reregistration process. The first
four phases of the process focus on identification of data requirements to support the
reregistration of an active ingredient and the generation and submission of data to fulfill the
requirements. The fifth phase is a review by the U.S. Environmental Protection Agency
(referred to as "the Agency") of all data submitted to support reregistration.
FIFRA Section 4(g)(2)(A) states that in Phase 5 "the Administrator shall determine
whether pesticides containing such active ingredient are eligible for registration" before
calling in data on products and either reregistering products or taking "other appropriate
regulatory action." Thus, reregistration involves a thorough review of the scientific data
base underlying a pesticide's registration. The purpose of the Agency's review is to reassess
the potential hazards arising from the currently registered uses of the pesticide; to determine
the need for additional data on health and environmental effects; and to determine whether
the pesticide meets the "no unreasonable adverse effects" criterion of FIFRA.
This document presents the Agency's decision regarding the reregistration eligibility
of the registered uses of zinc chloride, zinc oxide and zinc sulfate. The document consists of
six sections. Section I is the introduction. Section II describes these zinc salts, their uses,
data requirements and regulatory history. Section HI discusses the human health and
environmental assessment based on the data available to the Agency. Section IV presents the
reregistration decision for zinc salts. Section V discusses the reregistration requirements for
zinc salts. Finally, Section VI is the Appendices which support this Reregistration Eligibility
Document. Additional details concerning the Agency's review of applicable data are
available on request.'
1 EPA's reviews of data on the set of registered uses considered for EPA's analysis may be
obtained from the OPP Public Docket, Field Operations Division (H7506C), Office of Pesticide
Programs, EPA, Washington, DC 20460.
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II. CASE OVERVIEW
A. Cfiemical Overview
The following active ingredients are covered by this Reregistration Eligibility Document:
o Common Name: Butter of zinc
Chemical Name: Zinc chloride
CAS Registry Number: 7646-85-7
Office of Pesticide Programs Chemical Code: 087801
Empirical Formula: ZnCl2
o Common Name: Flowers of zinc; philosopher's wool; zincite (mineral); zinc white
Chemical Name: Zinc oxide
CAS Registry Number: 1314-13-2
Office of Pesticide Programs Chemical Code: 088502
Empirical Formula: ZnO
Common Name: Dried zinc sulfate
Chemical Name: Zinc sulfate monohydrate
CAS Registry Number: 7446-19-7
Office of Pesticide Programs Chemical Code: 527200
Empirical Formula: ZnSO4 H2O
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B. Use Profile
The following is information on the current registered uses with an overview of use sites and
application methods. A detailed table of these uses of zinc chloride, zinc oxide and zinc
sulfate is in Appendix A.
For zinc chloride:
Type of Pesticide: Herbicide and preservative
Use Sites: Terrestrial non-food, Outdoor residential
Target Pests: Moss, fungi
Formulation Types
Registered:
Soluble concentrate - 6.2% zinc chloride
Ready to use liquid -26% zinc chloride
Method and Rates
of Application: Equipment - Hose-end sprayer; non-aerosol pump; tank type
sprayer, sprinkler can.
Method and Rate - Apply (sprinkle or spray) 3 gallons per 100
sq.ft.
Timing - When needed.
For zinc oxide:
Type of Pesticide: Fungicide, herbicide, bacteriostat
Use Sites: Terrestrial non-food, outdoor residential, indoor non-food
Target Pests: Moss, fungi, bacteria
Formulation Types
Registered: Wettable powder- 20.76% zinc oxide;
Metal strip- 99.1 % zinc
Powder- 99% zinc oxide (formulation intermediate)
Powder-99.4% zinc oxide (industrial preservative)
Method and Rates
of Application: Equipment - sprinkler can (for wettable powder); galvanized
nails (for metal strip)
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Method and Ratg - Dissolve 1 Ib. in 5 gallons of water. For
metal strip, apply along all roof peaks using galvanized or
aluminum nails.
Timing - When needed.
For zinc sulfate:
Type of Pesticide: Herbicide
Use Sites: Terrestrial non-food. Residential outdoor
Target Pest: Moss
Formulation Types
Registered: Wettable powder- 99% zinc sulfate monohydrate
Method and Rates
of Application: Equipment - Apply by hand or use sprinkling can or pump-type
sprayer.
Method and Rate - Apply as a powder along the ridge of the
roof; dissolve in 5-10 gallons of water to cover 600 sq. ft. for
gravel or paved surfaces.
Timing - When needed.
C.
Reeulatorv History
Pesticidal products containing zinc salts were first registered in the United States in
1973. The uses include moss control in areas where moss growth is profuse due to high
precipitation rates, primarily in the Northwestern U.S. Zinc oxide is also incorporated into
carpet fibers as a bacteriostatic and fungistatic agent and as an ingredient in a solution for
pressure treatment of wood.
The major use of zinc salts in the United States is non-pesticidal, as a fertilizer
micronutrient. Other uses include as an electrolyte in dry cell batteries, as an animal feed
additive, as a galvanizer and as an emulsion-breaker.
ffl. SCIENCE ASSESSMENT OF ZINC SALTS
The Agency has conducted a thorough review of the scientific data base for zinc salts
for the purposes of determining the reregistration eligibility of these pesticides. These
finding are summarized below. The complete references cited in the text are in the
Bibliography (Appendix C).
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A. physical Chemistry Assessment
Zinc chloride is a clear, very deliquescent salt. It has a boiling point of
260°C and at room temperature it is completely soluble in water. The vapor pressure
is 1.5 mmHg and the pH is 5.4. Outstanding generic physical chemistry data
requirements are listed in Section V.
Zinc oxide is an odorless white or yellowish-white powder. It has a melting
point of 2010°C and its density is 0.481 gm/crn3. It is relatively insoluble in water,
has a pH of 7.37 and is stable.
Zinc sulfate monohydrate is an odorless white solid. It has a melting point of
600°C and a density of 1.121 gm/cmj. It is soluble in water up to 35% and is stable.
Additional physical chemistry data requirements are listed in Section V
Zinc metal is an odorless bluish-white lustrous solid. It has a melting point of
419°C and a density of 7.169 gm/cm1. It is insoluble and has a low stability in the
natural environment, easily forming the solid phases ZnO, Zn(OH)2 and Zn303 and
soluble zinc ions.
B. HUMAN HEALTH ASSESSMENT
1. Toxicology - Data Base
The lexicological data base on zinc oxide, zinc chloride, and zinc
sulfate is adequate and will support reregistration eligibility.
a. Acute Toxicity
Zinc oxide:
ACUTE TQXICITY VALUES
TEST
Oral LD50--rat
Dermal LDSO-rabbit
Eye effects-rabbit
Skin effects-rabbit
RESULT (mg/kg)
>5000
>5000
mild irritant
non-irritant
TOXICITY |
CATEGORY J
IV !
111 !
Ill :
IV l
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The TDlo was reported as 6846 mg/kg in an oral test in rats (I).
An oral LD50 in mice was reported as >7950 mg/kg (2). One report
states that 500 mg applied for 24 hours produced mild irritation on skin
or eyes of rabbits. A TClo reported for human inhalation was 600
mg/m3 of zinc oxide (1).
Zinc chloride:
ACUTE TOXICITY VALUES
TEST
Oral LD50--rat
Inhalation LClo— human
Eye effects
Skin effects
RESULT (mg/kg)
350
4800 mg/m3/30min
Corrosive
Corrosive
TOXICITY
CATEGORY
II
III
I
I
Acute oral tests found the LD50 was 350 mg/kg in rats and in
mice, and 200 mg/kg in guinea pigs (1). The human TClo for
inhalation has been reported as 4800 mg/mj/30 minutes (1).
Zinc sulfate:
ACUTE TOXICITY VALUES
TEST
Oral LD50--rat
Eye effects-rabbit
Skin effects
RESULT (mg/kg)
>2949
severe irritation
very slight irritation
TOXICITY
CATEGORY
III
I
IV
Acute oral tests found the LDlo was 333 mg/kg in rats and 2000
mg/kg in rabbits; the LD50 was >2949 mg/kg in rats and 1891
mg/kg in mice (1,2). Another acute oral study found the LD50
was 1374 mg/kg in rats (3). The oral TDlo for humans is
reported to be 45 mg/kg/7 days (continuous), 106 mg/kg, and
180 mg/kg/6 weeks (intermittent) (1, 2). A dermal irritation
study in rabbits with 99% zinc sulfate found very slight
irritation. In one study, severe irritation was found when 0.09g
of 99% zinc sulfate was applied to rabbit eyes. In another study,
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the application of 420 ug zinc sulfate to the rabbit eye found
moderate irritation (1).
b. Subchronic Toxicity
There was no evidence of toxicity in humans fed 10 mg/kg/day
of zinc sulfate for up to 3 months (3).
c. Metabolism
Zinc is an essential element in human nutrition and is involved
in the nutrition of all plants and animals. It is an integral component of
several metalloenzymes in various metabolic systems and is present in
every cell (3). In test animals, 8-10 percent of ingested zinc was
absorbed in the intestine and the rest excreted in the feces (3).
Ingestion of large amounts of zinc salts induces a variety of
metabolic changes, with inhibition of some enzymes, effects on
excretion, and a reduction in size and hemoglobin content of red blood
cells (microcytic hypochromic anemia) (3).
It has been calculated that the consumption of zinc salts added to
food may be 0.50 mg of elemental zinc per person per day and the
intake of zinc occurring naturally in food may be 5 to 22 mg per day
(3).
d. Chronic Toxicity, Carcinogenicity
In some long-term studies, extending for one year and over
three generations of rats, zinc chloride, oxide, and sulfate showed no
effects at levels up to 0.25 percent of the diet (3). In other studies,
zinc sulfate caused hematological changes in rats and dogs fed about
100 ppm in the diet (3).
No evidence of carcinogenicity was found in feeding zinc oxide
(at 34.4 mg zinc per day) to rats for 29 weeks. Carcinogenicity has
been reported in mice given zinc chloride in drinking water, but the
reports were not complete and controls were not used consistently. In
another report, mice given up to 5,000 ppm of zinc as zinc sulfate in
drinking water showed no evidence of carcinogenicity and no
differences between treated and control groups (3).
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e. Reproductive and Developmental Toxicity
When 6846 mg/kg of zinc oxide was given to pregnant rats on
days 1-22 of pregnancy, there were increased stillbirths and effects on
growth of the young (2).
When rats were given 333 mg/kg zinc sulfate orally on days l-
18 of pregnancy, there was post-implantation mortality (2). Teratologic
studies with oral zinc sulfate in three species of animals were negative
for effects on pregnancy, maternal or fetal survival, or abnormalities.
In these studies mice were given up to 30 mg/kg/day for days 6-15 of
gestation, rats were given up to 42.5 mg/kg/day for days 6-15 of
gestation, and hamsters were given up to 88 mg/kg/day for days 6-10
of gestation (3).
f. Mutagenicity
Positive results with zinc oxide have been reported in some
studies. DNA damage in Escherichia coli occurred at 3000 ppm, and
unscheduled DNA synthesis occurred in guinea pigs after exposure to
5300 ug/tnV3 hours/6 days in an inhalation study (1, 2).
Positive results with zinc chloride also have been reported in
several studies. Mutagenic effects were seen at 90 mmol/L in a
microsomal mutagenicity assay with Salmonella lyphimurium.
Unscheduled DNA synthesis in human lymphocytes occurred at 180
umol/L and at 360 umol/L. DNA inhibition was seen in human
lymphocytes. In cytogenetic analyses, effects were seen in mice treated
orally with 18 g/kg for 30 days and in human lymphocytes treated with
300 umol/L. Effects also were seen in a host-mediated assay with mice
and Salmonella typhimurium at 6 mg/kg and at 180 umol/L in an
oncogenic transformation assay using hamster embryos (1).
Positive results have been seen with zinc sulfate in some studies,
including a Drosophila melanogaster sex chromosome assay with an
oral 5mmol/L dose and a mutation assay with Saccharomyces cerevisiae
at 100 mmol/L. DNA inhibition was seen in human HeLa cells at 1
umol/L/4 hours and oncogenic transformation occurred at 200 umol/L
with hamster embryo (1, 2).
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2. Dietary Exposure
There are no pesticidal food uses for zinc. Zinc is widely
distributed in plants, animals and food, and is a normal part of
metabolism in all living organisms.
The Food and Drug Administration lists these zinc salts as
generally recognized as safe for use in food as dietary supplements and
as nutrients: zinc oxide in 21 CFR 182.5991 and 182.8991, zinc
chloride in 21 CFR 182.5985 and 182.8995, and zinc sulfate in 21
CFR 182.5997 and 182.8997.
3. Occupational and Residential Exposure
The lexicological data base on these zinc salts is adequate and will
support reregistration. Therefore, no new exposure data are necessary.
Based on the application methods (specified and implied) and the
formulation types, the potential for significant eye, inhalation and
dermal exposure to concentrated solutions or dusts exists for mixers,
loaders, and applicators. Accordingly, the zinc salt labels must
consistently reflect any potential eye and skin hazard (Danger, Warning
or Caution Signal Words) and recommend appropriate protective
equipment (protective eyeware [goggles or face shield], long sleeved
shirts and long-legged pants, waterproof gloves, shoes and socks).
However, there is no reason to expect reasonable pesticide usage to
constitute any hazard beyond ordinary non-pesticidal exposure to zinc
salts if label directions are followed, and the Agency believes that the
uses of these products do not represent an unreasonable hazard to
workers.
4. Risk Assessment
The lexicological data on these zinc salts in public literature are
adequate for assessing risk to humans. Accordingly, additional studies
are not required for the reregistration of present uses of these salts.
Although some positive mutagenicity studies have been reported, there
is no indication of mutagenic effects in normal living organisms from
everyday exposure. Living organisms have long been exposed to the
components of these zinc salts without such exposure being attributed to
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c.
mutagenicity. Zinc is widely distributed in plants, animals and soils and
is normally present in food. Zinc is a normal part of metabolism in all
living organisms. These zinc salts are also added ingredients in foods.
There is no reason to expect appropriate pesticide usage to
constitute any hazard beyond ordinary exposure from non-pesticidal
sources. There are no significant exposure concerns other than those
addressed by appropriate label precautions for eye and dermal
protection for the mixers, loaders, and applicators. Refer to section V
. for product labeling requirements.
Environmental Assessment
1.
Environmental Fate
The Agency is relying on data available in the scientific
literature to assess the environmental fate and transport of zinc salts as
used in pesticidal compounds. No data were submitted by registrants.
a. Environmental Fate and Transport
Zinc chloride and zinc sulfate are very soluble in water;
zinc oxide is relatively insoluble. The dissolution of zinc
compounds in water results in the formation of various species
of zinc ions which, in the absence of complexing or chelating
agents, is dependent on pH. Zinc oxide is less soluble than zinc
chloride or zinc sulfate, but dissolves in more acidic media to
form ZnOH* and [Zn(H2O)6]2* . In a more basic pH, zinc oxide
dissolves to form [Zn(OH)3]' and [Zn(OH)4]2'. In natural waters
(both freshwater and seawater), identification of which species
of zinc ion is present is difficult due to the presence of organic
and inorganic natural complexing agents.
Based on calculations using equilibrium constants and in
the absence of organic complexing agents, [Zn(H2O)6)]2+,
ZnOH* and Zn(OH)2 are the predominant species in freshwater.
Zn-chloro complexes may also be present in seawater.
The availability of zinc to plants and other organisms in
soil decreases with increased soil pH. Several components of
soil (clay minerals, mineral oxides and hydroxides, carbonates
and organic matter) can absorb zinc (predominantly as ZnOH*).
Zinc therefore can be considered as relatively immobile in most
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b.
Environmental Fate Assessment
Zinc is necessary to ail forms of life and any toxicity
associated with zinc can be attributed to the presence of "free"
zinc and not to total zinc concentration. The Agency has
concluded that the addition of zinc to the environment in the
form of zinc salts used as pesticides will not result in a
significant increase in "free" zinc. This conclusion is based on
indications that "free" zinc is immobilized by various organic
and inorganic substances and by formation of insoluble phases.
thereby making it less bioavailable. Therefore, the terrestrial use
of the pesticidal products containing the zinc salts covered in
this document is not likely to result in the movement of "free"
zinc in soils, and there are no additional environmental fate data
required for the reregistration of the zinc salts.
2. Ecological Effects
Ecological effects data have been submitted for zinc oxide only.
Published information also was used by the Agency to assess the risk
posed by the use of pesticides containing zinc to non-target organisms.
a. Ecological Hazard
1. Ecological Effects Data
Avian toxicity studies were submitted by registrants.
Since most of the applied zinc salts will transform (or become
immobile in soil) to zinc oxide/hydroxide, and since the use of
these products is on a relatively low volume basis, the avian
studies for zinc oxide are sufficient for the other active
ingredients. An acute oral toxicity study in bobwhite quail
provided an LDW of 606 mg/kg. In an acute dietary study in
bobwhite quail, the LC50 was greater than 5000 ppm. These
studies provide sufficient information to classify the acute
toxicity of zinc salts as slightly to practically non-toxic to birds.
Published studies show that coturnix quail fed a diet containing
1.5% zinc oxide had reproductive effects (4). Mallards fed a
diet of 3,000-12,000 ppm zinc showed decreased feed
consumption and body weight (5) and laying hens showed
decreased egg production, shell strength and hatchability on a
diet containing 20,000 ppm zinc (6).
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b. Environmental Fate Assessment
Zinc is necessary to all forms of life and any toxicity
associated with zinc can be attributed to the presence of "free"
zinc and not to total zinc concentration. The Agency has
concluded that the addition of zinc to the environment in the
form of zinc salts used as pesticides will not result in a
significant increase in "free" zinc. This conclusion is based on
indications that "free" zinc is immobilized by various organic
and inorganic substances and by formation of insoluble phases,
thereby making it less bioavailable (). Therefore, the terrestrial
use of the pesticidal products containing the zinc salts covered in
this document is not likely to result in the movement of "free"
zinc in soils, and there are no additional environmental fate data
required for the reregistration of the zinc salts.
2. Ecological Effects
Ecological effects data have been submitted for zinc oxide only.
Published information also was used by the Agency to assess the risk
posed by the use of pesticides containing zinc to non-target organisms.
a. Ecological Hazard
I. Ecological Effects Data
Avian toxicity studies were submitted by registrants.
Since most of the applied zinc salts will transform (or become
immobile in soil) to zinc oxide/hydroxide, and since the use of
these products is on a relatively low volume basis, the avian
studies for zinc oxide are sufficient for the other active
ingredients. An acute oral toxicity study in bobwhite quail
provided an LDW of 606 mg/kg. In an acute dietary study in
bobwhite quail, the LC*, was greater than 5000 ppm. These
studies provide sufficient information to classify the acute
toxicity of zinc salts as slightly to practically non-toxic to birds.
Published studies show that coturnix quail fed a diet containing
1.5% zinc oxide had reproductive effects (4). Mallards fed a
diet of 3,000-12,000 ppm zinc showed decreased feed
consumption and body weight (5) and laying hens showed
decreased egg production, shell strength and hatchability on a
diet containing 20,000 ppm zinc (6).
Studies submitted to the Agency, as well as published
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literature, were used to assess the toxicity of these zinc salts to
non-target organisms in aquatic or estuarine ecosystems;
however, the results were highly variable. The LCjo for bluegill
sunfish was greater than 320 ppm but was 1.1 ppm in rainbow
trout in studies submitted to the Agency, while the 96 hr LC50
reported in the literature ranged from 1.2-17.9 ppm for
freshwater fish (7,8). Acute toxicity in Daphnia magna was
greater than 1000 ppm (i.e. practically non-toxic) in a study
submitted to the Agency. Data from the literature were variable,
indicating that zinc may be highly toxic to freshwater
invertebrates (9). However, in two published studies, the 96 hr
LCs<, values ranged from 0.25-18.4 ppm in freshwater
invertebrates (7,8). In conclusion, although the data showed
extreme variability of results, at least two of the studies
indicated that zinc oxide may be highly toxic to both freshwater
fish and freshwater invertebrates.
b. Ecological Effects Risk Assessment
Zinc is relatively non-toxic to avian populations
and is used as a feed additive for animals. Given the use
patterns and frequency of application of pesticidal
products containing these zinc salts, it is unlikely that
zinc would be available in toxic amounts to avian or
other non-target animal and insect populations in
terrestrial environments as a result of their use. Although
zinc may be toxic to aquatic organisms in some
environments, based on the environmental fate
assessment, aquatic exposure resulting from the use of
these products is expected to be negligible. Therefore,
the Agency has determined that these products, as they
are currently registered, pose no unreasonable risk to the
environment.
The textile industrial preservative use of zinc
oxide results in indirect discharge of effluent containing
zinc into natural waters. An assessment of the risk posed
to aquatic organisms resulting from this route of
exposure is under the purview of the Agency's Office of
Water and will not be covered in this document.
Although the aquatic toxicity studies showed variability
in results, they are adequate to determine the appropriate
label statements for this industrial preservative. The
required label precaution statement is included in section
V.
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IV. RISK MANAGEMENT AND RERECfSTRATION DECISION FOR ZCVC SALTS
A. Determination of Eligibility
Section 4(g)(2)(A) of FIFRA calls for the Agency to determine, after
submission of relevant data concerning an active ingredient, whether products
containing the active ingredient are eligible for registration. The Agency has
completed its review of data from the open literature and generic data submitted by
registrants, and has determined that the data are sufficient to support reregistration of
products containing zinc salts. Appendix B identifies the generic data that the Agency
reviewed as part of its determination of reregistration eligibility of zinc salts, and lists
the submitted studies that the Agency found acceptable.
The data identified in Appendix B were sufficient to allow the Agency to
assess registered uses of zinc salts and to determine that these uses can be used
without resulting in unreasonable adverse effects to humans and the environment.
The Agency therefore finds that products containing zinc salts as an active ingredient
are eligible for reregistration. The reregistration of particular products is addressed in
Section V of this document.
The Agency made its reregistration eligibility determination based upon the
target data base required for reregistration, the current guidelines for conducting
acceptable studies to generate such data and the data identified in Appendix B.
Although the Agency has found that current products containing zinc salts are eligible
for reregistration, it should be understood that the Agency may take appropriate
regulatory action, and/or require the submission of additional data to support the
registration of products containing zinc salts, if new information comes to the
Agency's attention or if the data requirements for reregistration (or the guidelines for
generating such data) change.
The following is a summary of the regulatory positions and rationales for zinc
salts. Where labeling revisions are imposed, specific language is set forth in Section
V of this document.
Eligibility Decision
The Agency has sufficient information on the human health effects of zinc salts
and on its potential for causing effects in fish and wildlife and the environment when
used to control moss and fungus growth in outdoor residential areas, on structures, in
pressure-treated lumber and incorporated into fibers used in carpet. The Agency
concludes that products containing zinc salts for these uses are eligible for
reregistration. Only certain generic physical chemistry data studies on zinc salts still
are needed as confirmatory information. The Agency has determined that zinc salt
containing products, labeled and used as specified in this Reregistration Eligibility
14
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Document, will not pose unreasonable risks or adverse effects to humans or the
environment.
Eligible and Ineligible Uses
The Agency has determined that all registered uses are eligible for
reregistration at this time.
B. Regulatory Position
Tolerances and Action Levels
There are no registered food uses or tolerances for products containing zinc
salts as an active ingredient.
V. ACTIONS REQUIRED BY REGISTRANTS
This section is designed to assist the registrant by providing data requirements and
responses necessary for the reregistration of manufacturing-use and end-use products.
A. Additional Generic Data Requirements
The generic data base supporting the reregistration of zinc salt-containing
products has been reviewed and determined to be substantially complete. Although
some of the generic product chemistry data requirements are acceptable, additional
data are required as confirmatory. These are part of the generic Data Call-in. These
generic data requirements are listed in Appendix F.
B. Product specific data requirements
1. Additional Product-Specific Data Requirements
Based on the reviews of the generic data for zinc salts, the products containing
zinc salts are eligible for reregistration. Section 4(g)(2)(B) of FIFRA calls for the
Agency to obtain any needed product-specific data regarding the pesticide after a
determination of eligibility has been made. The product specific data requirements
are listed in Appendix G, the Product Specific Data Call-in Notice.
Registrants must review previous data submissions to ensure that they meet
current EPA acceptance criteria (Appendix G; Attachment E) and if not, commit to
conduct new studies. If the registrant believes that previously submitted data meet
current testing standards, then study MRID numbers should be cited according to the
instructions in the Requirement Status and Registrants Response Form provided for
each product.
15
-------
C. Labeling Requirements for Manufacturing and End-Use Products
End-Use Produces
The labels and labeling of all products must comply with EPA's current
regulations and requirements as specified in 40 CFR §156.10. Labels must
consistently reflect any potential eye and skin hazard (Danger. Warning or Caution
Signal Words) and recommend appropriate protective equipment (protective eyeware
[goggles or face shield], long sleeved shirts and long-legged pants, waterproof gloves.
shoes and socks). Please follow the instructions in the Pesticide Reregistration
Handbook with respect to labels and labeling.
Manufacturing use (Includes Industrial Preservatives)
In addition to the above requirements for end-use products, labels and labeling
of all manufacturing use products must contain the following statement:
"This pesticide is toxic to fish and aquatic invertebrates. Do not discharge
effluent containing this product into lakes, streams, ponds, estuaries, oceans or public
waters unless this product is specifically identified and addressed in an NPDES
permit. Do not discharge this product into sewer systems without previously notifying
the sewage treatment plant authority. For guidance, contact your State Water Board or
Regional Office of U.S. EPA."
16
-------
APPENDIX A
Table of Zinc Salts Use Patterns
Subject to Re registration
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APPENDIX B
Table of The Generic Data Requirements and
Studies Used to Make the Reregistration Decision
-------
GUIDE TO APPENDIX B
Appendix B contains listings of data requirements which support the reregistration for the
zinc salts covered by this Reregistration Eligibility document. It contains generic data
requirements that apply to zinc salts in all products, including data requirements for which a
"typical formulation" is the test substance.
The data table is organized in the following format:
1. Data Requirement (Column 1). The data requirements are listed in the order in which
they appear in 40 CFR Pan 158. the reference numbers accompanying each test refer to the test
protocols set in the Pesticide assessment Guidelines, which are available from the National
Technical Information Service, 5285 Port Royal Road, Springfield, VA 22161 (703) 487-4650.
2. Use Pattern (Column 2). This column indicates the use patterns for which the data
requirements apply. The following letter designations are used for the given use patterns:
A Terrestrial food
B Terrestrial feed
C Terrestrial non-food
D Aquatic food
E Aquatic non-food outdoor
F Aquatic non-food industrial
G Aquatic non-food residential
H Greenhouse food
I Greenhouse non-food
J Forestry
K Residential
L Indoor food
M Indoor non-food
N Indoor medical.
O Indoor residential
3. Bibliographic citation (Column 3). If the Agency has acceptable data in its files, this
column lists the identifying number of each study. This normally is the Master Record
Identification (MRID) number, but may be a "GS" number if no MRID number has been
assigned. Refer to the Bibliography appendix for a complete citation of the study.
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