  SEQ CHAPTER \h \r 1 United States 			Prevention, Pesticides		September
2007

  Environmental Protection                 and Toxic Substances

  Agency                                             (7510P)	

	

Zinc Borate 

Summary Document: 

Registration Review

Docket Number:EPA-HQ-OPP-2007-0675

www.regulations.gov

Zinc Borate Summary Document

Registration Review: Initial Docket

September 2007

							Approved By:

							____________________

							Frank T. Sanders

							Director, Antimicrobials Division

							

Date:

_____________________



TABLE OF CONTENTS

Zinc Borate Registration Review Team
Members………………………………...	4

I. Preliminary Work
Plan….……………………………………………………….
.	  5

II. Fact
Sheet…………………………………………………………
………………	 11

III. Status of Human Health and Ecological Risk Assessment for Zinc
Borate…	 14

	A.
Introduction…………………….……………………………
…………...	14

	B. Use
Profile……………………….………………………………
………..	16

	C. Human Health Exposure and Risk
Assessment…...……………………	17

	D. Physical/Chemical Properties and Environmental
Fate……………….	22

	E. Ecological Exposure and Risk
Assessment...……………………………	23

IV. Glossary of Terms and
Abbreviations………………….……………...………	25

V.
Appendices……………………………………………………
………………….	27

	A. Application and Specific Use
Information……………….………….….	28

	B. Toxicity Guideline Study
Justification…………………...………….….	30

	C. Exposure Guideline Study
Justification………………..….....................	32

	D. Environmental Fate Guideline Study
Justification………...…………..	35

	E. Ecological Guideline Study
Justification...……………………………...	38



Zinc Borate Registration Review Team

Human   SEQ CHAPTER \h \r 1 Health & Environmental Effects 

Nathan Mottl

Srinivas Gowda

Risk Management

Michelle Centra

Diane Isbell

Office of General Counsel

Phil Ross

I. PRELIMINARY WORK PLAN

Introduction

The Food Quality Protection Act (FQPA) of 1996 amended the Federal
Fungicide Insecticide and Rodenticide Act (FIFRA) to mandate a new
program: registration review.  All pesticides distributed or sold in the
United States generally must be registered by EPA, based on scientific
data showing that they will not cause unreasonable risks to human
health, workers, or the environment when used as directed on product
labeling.  The new registration review program is intended to make sure
that, as the ability to assess and reduce risk evolves and as policies
and practices change, all registered pesticides continue to meet the
statutory standard of no unreasonable adverse effects.  Changes in
science, public policy, and pesticide use practices will occur over
time.  Through the new registration review program, the Agency
periodically reevaluates pesticides to make sure that as change occurs,
products in the marketplace can continue to be used safely.  Information
on this program is provided
at:http://www.epa.gov/oppsrrd1/registration_review/.

The Agency has begun to implement the new Registration Review program,
and plans to review each registered pesticide approximately every 15
years to determine whether it continues to meet the FIFRA standard for
registration.  The public phase of registration review begins when the
initial docket is opened for each case.  The docket is the Agency’s
opportunity to state clearly what it knows about the pesticide and what
additional risk analyses and data or information it believes are needed
to make a registration review decision.  Zinc borate is an antimicrobial
pesticide used in materials preservative applications and wood
preservative (wood composite materials used above ground) applications.

Risk Assessment Status & Anticipated Risk Assessment and Data Needs

Human Health Risk Assessment Status

	No human health, dietary, occupational/residential risk assessments
have been performed for the active ingredient zinc borate.  Based on the
registered uses of zinc borate as a material preservative and wood
preservative, there is potential for occupational and residential
exposure and risk.  Therefore, the Agency anticipates conducting a
complete occupational and residential human health exposure risk
assessment for all zinc borate uses.  For a detailed discussion of the
anticipated human health exposure and risk assessment needs, please
refer to Section III, C. Human Health Exposure and Risk Assessment and
the supporting document, Summary of Human Health Effects Data for the
Zinc Borate Registration Review Decision Document, dated August 31,
2007.  

	

Dietary Assessment

	A dietary exposure risk assessment was not performed for zinc borate.
There are no current or proposed direct food or feed uses of zinc
borate, therefore, EPA has not established tolerances or exemptions from
tolerances in raw agricultural commodities or processed food and feed
products under the Federal Food, Drug and Cosmetic Act (FFDCA).  The
labels for zinc borate prohibit uses that would directly contact food
and the Agency does not consider these uses to be indirect food contact
uses (e.g., uses that involve indirect exposure to food such as
antimicrobial uses in food packaging and cutting boards) which would
commonly trigger a screening-level dietary assessment. 

Occupational and Residential Assessment

	Neither an occupational nor a residential assessment has been performed
for zinc borate.  The Agency anticipates that inhalation assessments for
workers will be required to assess inhalation exposure to zinc borate
situations in manufacturing settings for all material preservative and
wood preservative uses (e.g., coatings and paints, plastics and rubber,
and wood composite materials).  In addition, the Agency plans to conduct
assessments to examine occupational and residential painting
applications.  Occupational post-application exposures are expected to
be minimal and an assessment is not planned.  The Agency plans to
examine residential post-application oral exposure scenarios for
toddlers mouthing zinc borate treated plastic toys, representing a worst
case scenario.

Aggregate and Cumulative Exposure

	In examining aggregate exposure, EPA takes into account the available
and reliable information concerning exposures to pesticide residues in
food and drinking water, and non-occupational pesticide exposures.  Zinc
borate has no food use registrations and no tolerances.  Therefore,
aggregate exposures are not being evaluated.  EPA has not yet determined
whether zinc borate has a common mechanism with other compounds,
consequently a cumulative assessment will not be performed.

Anticipated Human Health Data Needs

No human health toxicity endpoints for the active ingredient zinc borate
have been established from the existing toxicity database. 
Consequently, additional data is needed to characterize potential hazard
to human health from the registered uses of zinc borate.  For further
details regarding the anticipated human health toxicity data needs
please refer to Section III, C. Human Health Exposure and Risk
Assessment and Appendix B, Exposure Guideline Study Justification.  In
addition, please refer to the supporting document, Summary of Human
Health Effects Data for the Zinc Borate Registration Review Decision
Document, dated August 31, 2007.

The Agency anticipates that the following data are needed to conduct a
complete human health exposure and risk assessment for all zinc borate
uses.  Please refer to Appendix B for a detailed description of the
anticipated toxicity database needs for zinc borate and Appendix C for a
detailed description of the anticipated occupational and residential
applicator and post-applicator exposure data needs for zinc borate.

Mammalian Toxicity Data Needs

(OPPTS GLN 870.1300) Acute Inhalation Toxicity in Rats

OPPTS (GLN 870.2600) Dermal Sensitization in Guinea pigs

(OPPTS GLN 870.3465) 90-Day Inhalation Toxicity in Rats

Occupational Applicator Exposure Data Needs

(OPPTS GLN 875.1300) Inhalation Outdoor Exposure

(OPPTS GLN 875.1400) Inhalation Indoor Exposure

(OPPTS GLN 875.1600) Data Reporting and Calculations

(OPPTS GLN 875.1700) Product Use Information

Residential Applicator Exposure Data Needs

(OPPTS GLN 875.1300) Inhalation Outdoor Exposure

(OPPTS GLN 875.1400) Inhalation Indoor Exposure

(OPPTS GLN 875.1600) Data Reporting and Calculations

(OPPTS GLN 875.1700) Product Use Information

Residential Post-Application Exposure Data Needs

 (OPPTS GLN 875.2700) Product Use Information

Anticipated Physical/ Chemical Property Data Needs

All product chemistry data requirements have been fulfilled for the
active ingredient zinc borate.  Additional product chemistry data are
not needed for the registration review of zinc borate.

Anticipated Environmental Fate Data Needs

	The Agency has no environmental fate data nor has it conducted an
environmental fate assessment for zinc borate.  Environmental fate data
are needed because of potential exposures to waste water treatment
plants (WWTPs) and discharges into WWTP effluents (biosolids and/or
water). These data are needed to ascertain whether residues that may
occur in effluents and environmental compartments (e.g., surface waters)
will result in impacts to non-target organisms.  Therefore, the Agency
anticipates needing the proposed Tier I environmental fate data for the
active ingredient and/or any of its major degradation products that are
of potential concern for all registered uses of zinc borate.  The
following data are needed to conduct an environmental fate assessment:

(OPP GLN 161-1) Hydrolysis Study

(OPPTS GLN 850.6800) Modified Activated Sludge, Respiration Inhibition

(OPPTS GLN 835.1110) Activated Sludge Sorption Isotherm

(OPPTS GLN 835.3110) Ready Biodegradability 

(AWPA E11-06) Leachability of Wood Preservatives

It is possible that under specific conditions the Agency may need
additional environmental fate studies.  For a detailed discussion of the
environmental fate status and anticipated data needs please refer to
Section III, D. Physical/Chemical Properties and Environmental Fate, and
Appendix D, Environmental Fate Guideline Study Justification.  In
addition, please refer to the supporting document, Summary of Product
Chemistry, Environmental Fate and Ecotoxicity Data for the Zinc Borate
Registration Review Decision Document, dated August 31, 2007.

Ecological Exposure Risk Assessment Status

An ecological risk assessment has not been conducted for zinc borate and
the existing ecotoxicity database is incomplete and therefore, not
adequate for assessing the risks associated with the labeled uses of
zinc borate.  The limited ecotoxicity data for this active ingredient
indicate that the technical zinc borate is practically nontoxic to
birds, moderately toxic to practically non-toxic to fish, and slightly
toxic to daphnids.  The potential for zinc borate to be released into
the environment at exposure levels of concern to ecological organisms is
expected for both the materials preservative and wood preservative use
patterns.  

			The Agency anticipates conducting an ecological hazard assessment for
the active ingredient zinc borate and/or any of its metabolic/hydrolytic
degradates identified to be of potential concern.  The ecological hazard
assessment will be used to meet current labeling needs and to determine
hazard endpoints for ecological organisms that may be exposed to zinc
borate via potential environmental releases, such as a spill.

Preserved materials containing zinc borate may contaminate waste water
treatment plants (WWTPs) which may then be released into the aquatic
environment.  The Agency anticipates conducting a waste water treatment
plant (WWTP) risk assessment for wood preservative and materials
preservative releases.  Modeling will predict the amount of
antimicrobial that passes through a standard WWTP and the concentrations
that will subsequently enter the aquatic environment.  The WWTP model
estimates will be used in a deterministic risk assessment.  If analysis
of initial Tier I screening tests indicate that ecological toxicity and
magnitude of exposure to zinc borate exceed levels of concern for
drinking water and ecological effects, the Agency may need additional
data to refine the ecological risk assessment for the wood preservative
and materials preservative use patterns.

The planned ecological risk assessment will allow the Agency to
determine whether zinc borate’s use has “no effect” or “may
affect” federally listed threatened or endangered species (listed
species) or their designated critical habitat.  If the assessment
indicates that zinc borate “may affect” a listed species or its
designated critical habitat, the assessment will be refined.  The
refined assessment will allow the Agency to determine whether use of
zinc borate is “likely” to adversely affect the species or critical
habitat or “not likely to adversely affect” the species or critical
habitat.  When an assessment concludes that a pesticide’s use “may
effect” a listed species or its designated critical habitat, the
Agency will consult with the U.S. Fish and Wildlife Service and/or
National Marine Fisheries Service (Services), as appropriate.

For a detailed discussion of the status of the ecological exposure and
risk assessments for zinc borate refer to Section III, E. Ecological
Exposure and Risk Assessment and Appendix E, Ecological Guideline Study
Justification.  In addition, please refer to the supporting document,
Summary of Product Chemistry, Environmental Fate and Ecotoxicity Data
for the Zinc Borate Registration Review Decision Document, dated August
31, 2007. 

Anticipated Ecological Exposure Data Needs

The Agency anticipates needing the following data in order to conduct a
complete

ecological risk assessment, including an endangered species assessment
for all

uses:

o (OPPTS GLN 850.5400) Tier II Green Algae using Selenastrum
capricornutum

For a detailed discussion regarding the anticipated ecological data
needs refer to Section III E. Ecological Exposure and Risk Assessment
and Appendix E, Ecological Guideline Study Justification.  In addition,
please refer to the supporting document, Summary of Product Chemistry,
Environmental Fate and Ecotoxicity Data for the Zinc Borate Registration
Review Decision Document, dated August 31, 2007.

Time-line

EPA has created the following estimated timeline for the completion of
the Zinc Borate registration review.

Registration Review for Zinc Borate

Projected Registration Review Timeline

Activities 	Time

(Quarters are calendar year)

Opening Docket

Open Docket  	September, 2007

Public Comment Period  	December, 2007

Case Development

Final Work Plan 	1st Quarter 2008

Issue DCI 	4th Quarter 2008

Data Submission	4th Quarter 2010

Preliminary Risk Assessment 	2nd Quarter 2012

Public Comment Period	3rd Quarter 2012

Registration Review Decision

Proposed Registration Review Decision 	4th Quarter 2012

Public Comment Period 	1st Quarter 2013

Final Registration Review Decision &

Begin Post-Decision Follow-up	2013

Total (years)	6



Guidance for Commenters

The public is invited to comment on EPA’s preliminary registration
review work- plan and rationale.  The Agency will consider all comments
as well as any additional information or data provided prior to issuing
a final work plan for the zinc borate case.

Stakeholders are also specifically asked to provide available
information and data in the following areas:

Confirmation on the following label information:

Sites of application

Formulations

Application methods and equipment

Maximum application rates

Frequency of application, application intervals and maximum number of
applications

Geographic limitations on use

Use or potential use distribution 

Use history

Usage/use information for non-agricultural uses (e.g., materials
preservation)

Typical application interval

State or local use restrictions

Ecological incidents (non-target plant damage and avian, fish,
reptilian, amphibian and mammalian mortalities) not already reported to
the Agency

Monitoring data

Zinc borate is not identified as a cause of impairment for any
water-bodies listed as impaired under section 303(d) of the Clean Water
Act, based on information provided at:   HYPERLINK
"http://oaspub.epa.gov/tmdl/waters_list.impairments?p_impid=3" 
http://oaspub.epa.gov/tmdl/waters_list.impairments?p_impid=3 .  However,
the Agency invites submission of other existing water quality data for
this chemical.  To the extent possible, data elements outlined in
Appendix A of the “OPP Standard Operating Procedure: Inclusion of 
Water Quality & Impaired Water Body Data in OPP’s Registration Review
Risk Assessment & Management Process” should be provided in order to
insure that they can be used quantitatively or qualitatively in
pesticide risk assessments (see: (  HYPERLINK
"http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm" 
http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm ).

Next Step

Following closure of the 90-day comment period, the Agency will prepare
a Final Work Plan for this pesticide.

II. FACT SHEET

 

Background Information

Zinc Borate registration review case number: 5025

Zinc Borate PC Code: 128859

Zinc Borate CAS Registry#: 12447-61-9

Technical registrants: U.S. Borax, Inc., Lords Additives, Petroferm
Inc., and Royce Associates LP

First approved for use in a registered product: July 15, 1991

Not subject to reregistration (no Reregistration Eligibility Decision
[RED]) 

Antimicrobials Division Chemical Review Manager (CRM): Michelle Centra,
centra.michelle@epa.gov

Antimicrobials Division Product Manager (PM):  Adam Heyward,
heyward.adam.@epa.gov  

Chemical Identity/Structure of Zinc Borate:  3ZnO•2BO3•3.5H2O; mw
434.66

Use & Usage Information

For additional usage information and details, please refer to Appendix
A, Application Information for Zinc Borate (PC Code 128859).  

Zinc Borate is registered for use as an antimicrobial biocide/fungicide.

Zinc borate is used as a materials preservative in coatings and paints,
plastic and rubber products (carpet backing, wall coverings, auto
upholstery, shower curtains, and urethane mattresses, polyethylene wire
and cable, PVC tenting and awnings, acrylic roof coatings); and as a
wood preservative for wood composite materials (siding, roofing,
millwork, sheathing, subflooring).

There are four registered products containing Zinc Borate as an active
ingredient that are prepared as a powder for use in manufacturing
settings.

Pests controlled include bacteria and fungi. 

Application rates range from 0.05% to 4% Zinc Borate by weight of the
formulation (5000 ppm to 40,000 ppm).

Earlier Regulatory Actions

Registration of Zinc Borate (New Chemical), Memorandum: A. Lindsay, June
25, 1991.

Report of the Food Quality Protection Act (FQPA) Tolerance Reassessment
Eligibility Decision (TRED) for Boric Acid/Sodium Borate Salts July,
2006.    HYPERLINK "http://www.regulations.gov/" 
http://www.regulations.gov/   Docket ID#: EPA-HQ-OPP-2005-0062 

Reregistration Eligibility Decision (RED) September, 1993. [for Boric
Acid and Its Sodium Salts].    HYPERLINK
"http://www.epa.gov/pesticides/reregistration/status.htm" 
http://www.epa.gov/pesticides/reregistration/status.htm 

Reregistration Eligibility Decision (RED) Zinc Salts, September, 1992.  
 HYPERLINK "http://www.epa.gov/pesticides/reregistration/status.htm" 
http://www.epa.gov/pesticides/reregistration/status.htm 

 

Human Health Risk Assessment Status

At the present time, the Agency is unable to evaluate potential human
health risks for zinc borate because of limited data and the lack of
risk assessments currently available. For a detailed discussion of the
anticipated risk assessment and data needs for human health please refer
to Section III, Status of Human Health and Ecological Risk Assessment
for Zinc Borate and the supporting document, Summary of Human Health
Effects Data for the Zinc Borate Registration Review Decision Document,
dated August 31, 2007.  

Ecological Risk Assessment Status

Ecological risk assessments have not been conducted for zinc borate and
the existing database is incomplete and therefore, not adequate for
assessing the risk associated with zinc borate use.  The potential for
zinc borate to be released into the environment at exposure levels of
concern to ecological organisms is expected for most registered uses;
the Agency anticipates conducting risk assessments for wood
preservatives and material preservatives that potentially pass through
waste water treatment plants (WWTPs), and may be discharged into
terrestrial and aquatic environments.  The final zinc borate
registration review decision will include an endangered species effect
determination.  For a detailed discussion of the anticipated ecological
risk assessment and data needs, please refer to Section III, Status of 
Human Health and Ecological Risk Assessment for Zinc Borate and the
supporting document, Summary of Product Chemistry, Environmental Fate
and Ecotoxicity Data for the Zinc Borate Registration Review Decision
Document, dated August 31, 2007.

Tolerances 

There are no tolerances listed under 40 CFR 180.448 for zinc borate; the
EPA has not established tolerances or exemptions from tolerances in raw
agricultural commodities or processed food and feed products under the
Federal Food, Drug and Cosmetic Act (FFDCA) because there are no
proposed direct or indirect food or feed uses for zinc borate. 

Data Call-In Status

A data call-in has not been issued for zinc borate.  As it was
registered in 1991, it is not subject to reregistration.

Labels 

There are four registered products for the active ingredient zinc
borate.  Due to the limited number of products associated with this
active ingredient, the product labels have been included within the zinc
borate docket (ID#: EPA-HQ-OPP-2007-0675).  A list of registration
numbers is included in Table 1.  Product registration labels may also be
obtained from the Pesticide Product Label System (PPLS) website at:  
HYPERLINK "http://oaspub.epa.gov/pestlabl/ppls.home" 
http://oaspub.epa.gov/pestlabl/ppls.home .



Table 1. Registrations for Zinc Borate 

EPA Reg. No.	

Product Name	

Formulation Type	

Percent Active Ingredient	

Registrant





1624-120 

	

Borogard® ZB	

Powder 

(use in manufacturing setting)	

100%	

U.S. Borax, Inc.



73032-1 

	

Lord’s ZB-Shield	

Powder 

(use in manufacturing setting)	

99.8%	

Lords Additives



74981-1 

	

Storshield ZB 2335	

Powder 

(use in manufacturing setting)	

99% 	

Petroferm Inc.



75630-1

	

Zinc Borate	

Powder 

(use in manufacturing setting)	

99.5%	

Royce Associates LP



III.  STATUS OF HUMAN HEALTH AND ECOLOGICAL RISK ASSESSMENT FOR ZINC
BORATE (EPA PESTICIDE CHEMICAL CODE 128859; CAS REGISTRY# 12447-61-9)
(REGISTRATION REVIEW CASE NUMBER 5025)

A.  INTRODUCTION

	The active ingredient, zinc borate, present in the registered products,
Borogard® ZB, Lord’s ZB-Shield, Storshield ZB 2335, and Zinc Borate,
is an antimicrobial pesticide used in materials preservative
applications and as a wood preservative for wood composite materials
used in above ground applications.  This active ingredient will be
undergoing registration review to determine potential human and
ecological exposures and risks from these uses.  The Agency has
evaluated the human health and ecological assessments to determine the
scope of work necessary to support the registration review.  During
registration review, potential human and ecological toxicity,
physical/chemical properties, environmental fate, exposures, and risks
as a result of registered uses will be examined.  Data needs are
determined largely by the potential human and ecological toxicity and
exposures associated with these types of uses.  Information on the use
profile of zinc borate is presented in Section B of this preliminary
work plan.  The status of human exposure and risk assessment is
presented in Section C.  The status of data on physical/chemical
properties and environmental fate is presented in Section D of this
report.  Ecological exposure and risk assessment status for zinc borate
is presented in Section E of this report.  The purpose of reviewing the
status of this registration review case is to determine whether
sufficient data are available, whether new human health and ecological
risk assessments are needed to support registration review, and to
report why the Agency feels it may be necessary to either require new
guideline studies and/or to conduct new risk assessments under the
registration review process.

Structure Activity Relationships

EPA must rely upon information of appropriate quality and reliability
for each decision made by the Agency.  In the Office of Pesticide
Programs (OPP), the evaluation process for a pesticide chemical
traditionally begins with the applicant’s submission of a set of
studies conducted with the specific pesticide chemical of interest.  The
use of the results of such testing (measured data) is a logical,
scientifically rigorous process that identifies the physical, chemical,
and environmental fate properties of the pesticide, as well as the dose
and endpoints at which an adverse effect can occur in various animal
species. 

Today, there is significant interest in alternative techniques, i.e.,
techniques other than data generation that could significantly inform
the Agency’s decision-making process.  Recently, OPP has made
increasing use of structure activity relationship (SAR) as part of its
regulatory decision-making process.  In the SAR process, a chemical's
molecular structure is compared to that of other chemicals for which
data are available.  These structural similarities are then used to make
predictive judgments about a chemical’s physical, chemical, and
biological properties.  Thus, the chemical’s physical, chemical, and
biological properties are a function of (or directly related to) the
chemical’s molecular structure.  Quantitative SAR is referred to as
QSAR.  To develop a QSAR, a selected set of measured data on a single
physical, chemical, or biological property is used to derive a model (an
equation) to predict the value of that property.  

	Since SAR assessments and QSAR modeling are another set of tools that
are available to Agency scientists, OPP has begun a process shift that
envisions shifting from the current study-by-study approach to an
approach in which the use of predicted data, generated using validated
models, is considered along with information from open literature and
studies specifically generated under Part 158 requirements.  All
relevant information would be considered as part of a
weight-of-the-evidence evaluation.  

At this time, EPA believes that for certain endpoints, especially
physical/chemical and fate properties, that SAR and QSAR might be
effectively utilized to fulfill these data requirements for many
antimicrobial pesticide chemicals.  When considering biological
properties, at this time, EPA believes that SAR and QSAR can be most
effectively utilized in the evaluation of chemicals that exhibit lower
toxicity for human health and/or ecotoxicity parameters.  This is
appropriate because the risk assessment for lower toxicity chemicals can
be stream-lined, i.e., a screening-level assessment procedure rather
than multiple tiers of assessments with progressively more data
requirements.

If stakeholders believe that submission of predicted data can fulfill
one of the data needs for zinc borate, then the Agency invites
submission of this information.  The submitter would be expected to
supply a rationale describing the utility of the information and provide
documentation on the scientific validity of the information.  The
determination that the predicted data fulfills the data requirement
would be at the sole discretion of the Agency.  Pre-submission
consultation with the Agency is encouraged.

Data Requirements and Data Waivers

The Agency employs a step-wise process to assist the registrant in
determining the data needed to support its particular product. The
actual data and studies needed may be modified on an individual basis to
fully characterize the use and properties of specific pesticide products
under review.  While EPA will assist the registrant in outlining data
needs, it is important to emphasize that it is the registrant's
obligation under FIFRA to demonstrate that an individual product meets
the standard under FIFRA and/or FFDCA.  Accordingly, registrants are
encouraged to consult with the Agency on the appropriate data
requirements, as outlined here, as related to their specific product
during this registration review process.

	Since there is much variety in pesticide chemistry, exposure, and
hazard the Agency tries to be flexible.  The Agency also recognizes,
however, that due to the particular nature and risk of some pesticides,
registrants may seek to obtain data waivers or may suggest alternative
approaches to satisfying data needs.  Some products may have unusual
physical, chemical, or biological properties or atypical use patterns
which would make particular data requirements inappropriate, either
because it would not be possible to generate the required data or
because the data would not be useful in the Agency’s evaluation of the
risks or benefits of the product.  The Agency will waive data needs it
finds are inappropriate, but will ensure that sufficient data are
available to make the determinations required by the applicable
statutory standards.

Considering the above, registrants may request to use surrogate data or
alternative methods to meet data needs or request a waiver of data based
upon chemistry, exposure, or hazard rationales that support their
position.  Registrants are encouraged to discuss the request with the
Agency before developing and submitting supporting data, information, or
other materials.  All waiver requests must be submitted to the Agency in
writing.  The request must clearly identify the data need(s) for which a
waiver is sought along with an explanation and supporting rationale why
the registrant believes the data requirement should be waived.  In
addition, the applicant must describe any unsuccessful attempts to
generate the required data, furnish any other information that the
registrant(s) believes would support the request, and when appropriate,
suggest alternative means of obtaining data to address the concern that
underlies the data requirement.  The Agency will review each waiver
request and subsequently inform the applicant in writing of its
decision.

B. USE PROFILE

	The uses of antimicrobial pesticide chemicals regulated under FIFRA are
highly variable and complex and have been organized into twelve
categories of use patterns based on similarity of use, pesticide
function, method of incorporation into end-use products, method of
application of end-use products, types of establishments in which
products are used, environmental media to which antimicrobials are
expected to be released, and types of receptors expected to come into
contact with antimicrobial pesticides.  The twelve general use patterns
for antimicrobial pesticides include:

  Agricultural premises and equipment;

  Food handling/storage establishments, premises, and equipment;

  Commercial, institutional and industrial premises and equipment;

  Residential and public access premises;

  Medical premises and equipment;

  Human drinking water systems;

  Materials preservatives;

  Industrial processes and water systems;

 Antifoulants and ballast water;

(10) Wood preservatives; 

(11) Swimming pools; and

(12) Aquatic areas.

	There are four registered products (EPA Registration numbers, 1624-120,
73032-1, 74981-1, and 75630-1 ) for the active ingredient, zinc borate. 
Of these 12 general use patterns for antimicrobial pesticides, two are
applicable to zinc borate: materials preservatives and wood
preservatives for wood composite materials.  Specific uses, general use
patterns, and the potential for long-term exposure determine data needs
for terrestrial and aquatic non-target organisms, environmental fate,
human toxicity, and occupational and residential exposures to the active
ingredient zinc borate.  Appendix A presents information on each of the
specific use sites for the general use patterns that are applicable to
zinc borate, including the method of application, application rate, and
range of percent by weight of active ingredient to be added to each use
site.

C. HUMAN HEALTH EXPOSURE AND RISK ASSESSMENT

	

	The Agency has evaluated the status of the health assessments for zinc
borate, which is a biocide/fungicide pesticide used as a materials
preservative in paints, and plastics and as a wood preservative for wood
composites.  Review of the existing hazard and exposure databases for
zinc borate attempts to determine whether changes in science policy or
deficiencies in these databases materially affected the overall risk
picture.  Therefore, the purpose of this evaluation is to determine
whether sufficient data are available to support registration review,
whether new human health assessments are needed to support registration
review, and to report why the Agency feels it may be appropriate to
conduct new risk assessments under the registration review process.

	No human health dietary, occupational, or residential risk assessments
have been performed for the active ingredient, zinc borate.  EPA
previously assessed zinc and boron, two degradates of zinc borate, in
separate Reregistration Eligibility Decision (RED) documents as well as
a tolerance reassessment (TRED) for boric acid/sodium borate salts that
established toxicity endpoints for boron.  However, no new toxicity data
for zinc borate or the zinc and boron ions have been submitted to the
Agency since registration.  These documents are available in OPP’s
Docket ID#: EPA-HQ-OPP-2007-0675 at   HYPERLINK
"http://wwwlregulations.gov"  http://wwwlregulations.gov .

 

Toxicology

	Zinc borate is a fine powder that is stable at room temperature. 
Although zinc borate is slightly soluble in water, at low pH and over
time, zinc borate can dissociate to zinc and borate ions in this medium.
 A leaching study showed a maximum amount of 1.3% zinc (after 20 days at
pH 6, 7 and 9) and 2.2% boron leaching from PVC and a maximum amount of
3.4% zinc (in 20 days at various pH values) and 30% boron leaching from
an acrylic latex paint formulation.  As noted in the introduction,
assessments have been conducted in the past for both the zinc and borate
ions.  Therefore, potential exposure to the parent compound may be a
concern for handlers of the powders and dilution liquids, whereas
exposure to the borate ion (boron) may be a concern for post-application
exposure to plastic, rubber or wood composite matrices. 

Toxicology Concerns of Zinc Borate – Parent Compound

	This human health assessment addresses the toxicity of zinc borate. 
When zinc borate was initially registered, EPA required only a Tier 1
toxicity data set which consisted mainly of acute toxicity data
requirements.  Zinc borate was classified as toxicity category IV for
acute oral and dermal (rats), as a mild eye irritant (rabbit), and was
not classified as an irritant or corrosive in skin (rabbits).  An
acceptable dermal sensitizer guideline study has not yet been submitted
by the registrant; the study deficiencies included lack of  positive
and/or negative control data.

	The acute inhalation toxicity test in rats was initially waived for
zinc borate. However, for registration review, EPA now anticipates that
an acute inhalation toxicity test in rats will be needed to better
characterize the expected zinc borate inhalation exposures for
mixers/loaders handling zinc borate powders in manufacturing settings
and/or commercial settings in which applicators may become exposed to
zinc borate mists from spraying paint or coatings.  A 90-day inhalation
study in rats will also be essential in order to characterize the risks
of potential short- and intermediate-term inhalation exposures to zinc
borate.

	In manufacturing situations, potential exposures to the parent
compound, zinc borate, can occur in the form of a powder.  Zinc borate
is not very soluble in liquids at ambient conditions and at neutral pH,
zinc borate dissociation is slow. Therefore, dermal absorption of zinc
borate in applicators from paints and/or coatings would be minimal, and
a quantitative assessment of dermal exposure will not be needed.

	In rubber or plastic matrices, zinc borate could potentially leach out
in the form of zinc ion and/or boron.  However, leaching of zinc and
boron occurs slowly and the amounts do not exceed 2% (1-2% boron and
zinc in PVC at 20 days) based on the result of the leaching study. 
Nevertheless, there is potential risk to human health from exposure to
small amounts of leached zinc and boron ions in zinc borate-containing
rubber or plastic matrices.  Therefore, the Agency plans to evaluate
this potential route of exposure.

Toxicology Concern of Zinc ion – Dissociated Product

	Zinc is ubiquitous in the environment and occurs in the earth’s crust
at an average concentration of approximately 70 mg/kg and this ion
exists in the form of zinc salts such as zinc sulfide, zinc carbonate,
and zinc oxide.  Zinc is also an essential nutrient in the body.  For
toxicological concerns, there are adequate toxicology studies in the
zinc database to evaluate incidental oral exposures.  At high levels,
oral exposure to zinc in animal studies may result in toxic effects such
as pancreatic and renal lesions as well as histological alterations in
the pituitary and adrenal glands.  In general, the levels of zinc
causing these toxicological effects occur at much higher dose levels
than the level recommended for nutritional use.  The Agency will likely
use the robust set of animal studies from the existing scientific
literature to select oral toxicology endpoints for risk assessment
purposes which are not currently available in the existing Zinc Salts
RED.

Toxicology Concern of Boric acid/Borate Ion– Dissociated Product

	In general, the toxicological database for boron is adequate for hazard
characterization and sufficient data are available to assess potential
susceptibility to infants and children.  Boron is a ubiquitous element
that occurs naturally in plants and water.  Humans ingest naturally
occurring boron in the diet and there is some data to suggest that trace
levels are required in the human diet.  At higher exposure levels, boron
causes toxicity.  A major target organ is the testes.  See Table 2 for a
summary of the toxicity endpoints for boron established in the most
recent Boric Acid/Sodium Borate Salts TRED.



  SEQ CHAPTER \h \r 1 Table 2.  Summary of Toxicological Endpoints Boric
Acid/Sodium Borate Salts

Exposure Scenario	

Factor Used in Risk Assessment	Study and Endpoint of Risk Assessment

Dietary Risk Assessment

Dietary (Acute and Chronic)- 

all populations

	NA	The contribution of boron residues from food/feed crop application
of boric acid/sodium borate salts to the total naturally occurring
background dietary boron intake from food and water is not considered to
be significant.  Endpoints for acute and chronic dietary exposures were
not selected for this risk assessment because it was determined that a
dietary risk assessment (food plus drinking water) was not necessary at
this time.

Residential Risk Assessment (Adults and Toddlers)

Cute Oral Exposure (Toddlers)

Acute, Short-term and Intermediate-term 	

Level of Concern MOE= 100*	MRID no: 40692310

Chronic (2-year) toxicity (dogs)

NOAEL = 8.8 mg/kg/day

LOAEL was not determined

MRID no: 40692308

Chronic (38-week) toxicity (dogs)

NOAEL was not determined

LOAEL= 40 mg/kg/day males and 46 mg/kg/day females

based on decreased body weight gain in males and females and testicular
atrophy in males.

MRID no 40692307

Subchronic (90-day) toxicity (dogs)

NOAEL= 4.1 mg/kg/day (males)

LOAEL= 32 mg/kg/day (males) based on testicular atrophy and anemia in
the subchronic toxicity study.

Inhalation

Short-term and Intermediate-term	NA	Inhalation exposure for zinc borate
is expected to be to zinc borate not to boron.

Dermal	NA	No evidence of absorption across intact skin.

Cancer	Not likely to be carcinogenic to humans



MOE = margin of exposure

LOC= level of concern

LOAEL=lowest observed adverse effect level

NOAEL= no observed adverse effect level

* LOC of 100 based on assigning a 10X for interspecies extrapolation and
10X for intraspecies variation. The special FQPA SF has been reduced to
1x because there are no residual uncertainties with regard to pre-
and/or postnatal toxicity.

Dietary Assessment

	A dietary exposure risk assessment was not performed for zinc borate.  
There are no direct food or feed uses for zinc borate, therefore, EPA
has not established tolerances or exemptions from tolerances in raw
agricultural commodities or processed food and feed products under the
Federal Food, Drug and Cosmetic Act (FFDCA).  The labels for zinc borate
prohibit food use and the Agency does not consider these uses to be
indirect food contact uses (e.g., antimicrobial uses that involve
indirect food exposures in food packaging and cutting boards) which
would commonly trigger a Tier I dietary screening-level assessment.

	It should be noted that there were exemptions for the requirements of
tolerances granted for boric acid and its sodium salts based on low
residue levels of boron for their use relative to the naturally
occurring boron levels in plants (CFR 180.1121).  However, the
contribution of boron from zinc borate is negligible compared to the
amount of boron that is naturally occurring.  In addition, the Food and
Drug Administration has designated that borax and boric acid are
generally recognized as safe (GRAS) as indirect food additives in
adhesive components, components of paper, paperboard, sizing, and
coatings.

	There are no pesticidal food uses for zinc and no associated
tolerances.  Zinc is widely distributed in plants, animals, and food,
and is a normal part of the metabolism in all living organisms.  The
Food and Drug Administration has designated that zinc salts are
generally recognized as safe (GRAS) as dietary supplements and as
nutrients.

Aggregate and Cumulative Exposure

	In examining aggregate exposure, EPA takes into account the available
and reliable information concerning exposures to pesticide residues in
food and drinking water as well as non-occupational pesticide exposures.
 Zinc borate has no food use registrations and no tolerances. 
Therefore, aggregate exposures are not being evaluated.  EPA has not yet
determined whether zinc borate has a common mechanism of toxicity with
other compounds, consequently a cumulative assessment will not be
performed.  If zinc borate is found to have a common mechanism of
toxicity with other compounds, a cumulative assessment would be
conducted.

Occupational/Residential Exposure

	Neither an occupational nor a residential assessment has been performed
for zinc borate.  The Agency plans to conduct risk assessments to ensure
that zinc borate salts meet the safety standards established by FIFRA,
as amended by FQPA.

 

	The Agency anticipates that inhalation occupational assessments will be
needed to assess inhalation exposure to zinc borate for open situations
in manufacturing settings for all material preservative and wood
preservative uses (e.g., coatings and paints, plastics and rubber, and
wood composite materials).  In addition, the Agency plans to conduct
inhalation assessments to examine exposures that result from
occupational and residential painting applications.

	Zinc borate is a powder at room temperature and potential inhalation
exposure to dust is possible via open-loading powder into mechanical
systems that incorporate the powder into plastics and rubber products,
paints and coatings, and wood composite materials.  The inhalation
exposure assessment can not be conducted at this time due to a lack of
toxicity endpoints.   When a toxicological inhalation endpoint is
established, the Agency will likely use task force submitted data to
conduct the inhalation occupational and residential exposure
assessments.  A dermal assessment for zinc borate will not be required.

	Occupational post-application exposures are expected to be minimal. 
Based on review of the available labels, zinc borate wood composite is
fabricated for housing construction use such as siding, roofing,
millwork, sheathing, and sub-flooring, and does not appear to be used
for outdoor residential construction of wood decks or playground
equipment.  Therefore, a residential post-application assessment for
zinc borate composite will not be required.

	The Agency plans to examine residential post-application oral exposure
scenarios for toddlers from mouthing zinc borate treated plastic toys as
a worst case estimate of incidental ingestion exposure from plastics. 
This assessment would also cover the zinc borate wood composite uses
(note the label does not specify use in playground equipment or decks). 
It should also be noted that the label does not specifically mention
that rubber or plastic impregnated with zinc borate is used in the
manufacture of toys.  However, the label does not prohibit this use. 
The assessment would represent a worst-case exposure scenario for
mouthing of zinc borate-treated toys or wood products.  The incidental
ingestion scenario for plastic toys will use the leaching data
previously submitted by the registrant(s) that quantifies the amount of
borate ion that leaches from plastic.  There are sufficient toxicity
data for zinc and borate ion to evaluate this oral exposure scenario. 
Appendix B and C provide detailed justifications for the requirement of
toxicity and exposure studies.  The Agency intends to require the
following human health studies for the registration review of zinc
borate: (1) dermal sensitization in guinea pigs (OPPTS GLN 870.2600); 
(2) acute inhalation toxicity in rats (OPPTS GLN 870.1300); (3) 90-day
inhalation toxicity in rats (OPPTS GLN 870.3465); (4) occupational
applicator inhalation outdoor exposure (OPPTS GLN 875.1300); (5)
occupational applicator  Inhalation Indoor Exposure (OPPTS GLN
875.1400); (6) occupational applicator exposure data reporting and
calculations (OPPTS GLN 875.1600); (7) occupational applicator product
use information (OPPTS GLN 875.1700); (8) residential applicator
inhalation outdoor exposure (OPPTS GLN 875.1300); (9) residential
applicator inhalation indoor exposure (OPPTS GLN 875.1400); (10)
residential applicator exposure data reporting and calculations (OPPTS
GLN 875.1600); (11) residential applicator product use information
(OPPTS GLN 875.1700); and (12) residential post-application product use
information (OPPTS GLN 875.2700). 

D. PHYSICAL/CHEMICAL PROPERTIES AND ENVIRONMENTAL FATE

Submission of physical/chemical property data is required for the
registration of zinc borate. The physical chemistry data provides the
Agency with information necessary to characterize hazard and evaluate
potential exposures including acute toxicity (inhalation), workers’
exposure (vapor pressure), and bioaccumulation (environmental fate). 
These studies are also used to determine disposal policies (ecological
effects).  In addition, storage stability data provides information
necessary for determining whether a product remains stable in a
formulation, etc.

The registrant has submitted all of the data required for identification
of physical/chemical properties of this active ingredient.  As a result,
the Agency does not anticipate requiring the registrant to provide any
additional product chemistry data for registration review.  The chemical
identity of zinc borate is presented in Table 3.

Table 3. Chemical Identity

Chemical Name	Zinc borate (3ZnO•2BO3•3.5H2O; mw 434.66)

Common/Trade Names	Zinc borate

CAS Number	12447-61-9

Structure	3ZnO•2BO3•3.5H2O



Additionally, the Agency is planning to determine (1) the potential of
antimicrobial pesticides and/or their major degradates to directly and
adversely affect biological treatment processes present in a wastewater
treatment plant (WWTP); (2) the amount of an antimicrobial pesticide
and/or its major transformation products present in influents to a WWTP
and in effluents (water or bio-solids) that a WWTP releases to the
environment; and (3) whether antimicrobial pesticides found in WWTP
effluents or environmental compartments, such as surface water, exceed
the Agency’s Levels of Concern (LOCs) for nontarget organisms.  One
source of antimicrobials in surface water is disposal of consumer
products such as soaps and detergents, into household wastewater.  Also,
if EPA determines that other use categories result in discharges to
WWTPs, then the Agency will conduct any other assessments normally
performed for these other use categories.

The anticipated environmental fate data needs for the technical grade of
the active ingredient zinc borate and/or any of its major degradates
that are identified to be of potential concern are: (1) hydrolysis study
(OPP GLN 161-1); (2) modified activated sludge respiration inhibition
test (OPPTS GLN 850.6800); (3) activated sludge sorption isotherm test
(OPPTS GLN 835.1110); (4) ready biodegradability study (OPPTS GLN
835.3110); and (5) leachability of wood preservatives (AWPA E11-06).
Data from the hydrolysis study will enable the Agency to determine if
the antimicrobial pesticide hydrolyzes in water discharged to WWTPs, in
aquatic effluents WWTPs discharged to surface waters, or in surface
waters.  The modified activated sludge respiration inhibition test will
allow the Agency to identify antimicrobial pesticides which could harm
microorganisms found in biological wastewater treatment systems and
would also indicate suitable concentrations for use in the ready
biodegradability study.  The activated sludge adsorption isotherm test
will allow EPA to assess the distribution of antimicrobials among the
aqueous, solid, and vapor phases of WWTPs.  In addition, this type of
study allows the Agency to identify those chemicals that are likely to
adsorb to sludge. Examination of the sludge compartment is necessary
since humans and nontarget organisms may potentially be exposed to
antimicrobials that adsorb strongly to sludge that are applied to land
as a soil amendment.  Finally, the activated sludge adsorption isotherm
test results will help determine which ready biodegradability test
method is most appropriate.   The ready biodegradability study will
enable the Agency to determine the likelihood that an antimicrobial will
biodegrade during the wastewater treatment process.  It is possible that
under specific conditions the Agency may need additional environmental
fate tests.  Further description of the environmental fate guideline
studies needed by the EPA is presented in Appendix D, Environmental Fate
Guideline Study Justifications.  

E. ECOLOGICAL EXPOSURE AND RISK ASSESSMENT 

	The Agency has not performed a label hazard assessment nor has it
conducted an ecological risk assessment for the active ingredient zinc
borate and/or any of its metabolic degradates identified to be of
potential concern.  As a result, the Agency will likely need the
following Tier II ecological toxicity study: algal toxicity in
freshwater green algae, Selenastrum capricornutum, conducted with the
technical grade active ingredient of zinc borate (OPPTS GLN 850.5400).

In order to perform wastewater treatment plant (WWTP) and ecological
risk assessments, the Agency must evaluate the toxicity of zinc borate
to nontarget and endangered or threatened terrestrial and aquatic
animals and plants.  The zinc borate use scenarios that have the
potential for environmental exposure are the materials preservative and
wood preservative uses.

	The justifications for guideline studies for ecological non-target
organisms and plants are presented in Appendix E.  As mentioned in this
appendix, these guideline studies will provide the Agency with endpoints
to be used in wastewater treatment plant surface water exposures.  It is
possible that following further review and under specific conditions,
the Agency may need additional ecological toxicity tests.

Further, the planned ecological risk assessment will allow the Agency to
determine whether zinc borate’s use has “no effect” or “may
affect” federally listed threatened or endangered species (listed
species) or their designated critical habitat.  If the assessment
indicates that zinc borate “may affect” a listed species or its
designated critical habitat, the assessment will be refined.  The
refined assessment will allow the Agency to determine whether use of
zinc borate is “likely” to adversely affect the species or critical
habitat or “not likely to adversely affect” the species or critical
habitat.  When an assessment concludes that a pesticide’s use “may
effect” a listed species or its designated critical habitat, the
Agency will consult with the U.S. Fish and Wildlife Service and/or
National Marine Fisheries Service (Services), as appropriate.

IV. GLOSSARY of TERMS & ABBREVIATIONS

ai		Active Ingredient

AR		Anticipated Residue

ASTM		American Society for Testing and Materials

AWPA		American Wood Preserver’s Association

CFR		Code of Federal Regulations

cPAD		Chronic Population Adjusted Dose

CSF		Confidential Statement of Formula

CSFII		USDA Continuing Surveys for Food Intake by Individuals

DCI		Data Call-In

DEEM		Dietary Exposure Evaluation Model

DFR		Dislodgeable Foliar Residue

DNT		Developmental Neurotoxicity

DWLOC		Drinking Water Level of Comparison

EC		Emulsifiable Concentrate Formulation

EDWC		Estimated Drinking Water Concentration

EEC		Estimated Environmental Concentration

EPA			Environmental Protection Agency

EUP		End-Use Product

FDA		Food and Drug Administration

FIFRA		Federal Insecticide, Fungicide, and Rodenticide Act

FFDCA		Federal Food, Drug, and Cosmetic Act

FQPA		Food Quality Protection Act

FOB		Functional Observation Battery

GENEEC		Tier I Surface Water Computer Model

IR		Index Reservoir

LC50	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, air or feed, e.g., mg/l, mg/kg or ppm.

LD50	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.

LOC		Level of Concern

LOAEL		Lowest Observed Adverse Effect Level

µg/g		Micrograms Per Gram

µg/L		Micrograms Per Liter

mg/kg/day		Milligram Per Kilogram Per Day

mg/L		Milligrams Per Liter

MOE		Margin of Exposure 

MRID	Master Record Identification (number).  EPA's system of recording
and tracking submitted studies.

MUP		Manufacturing-Use Product

NA		Not Applicable

NAWQA		USGS National Ambient Water Quality Assessment

NPDES		National Pollutant Discharge Elimination System

NR		Not Required

NOAEL		No Observed Adverse Effect Level

OPP		EPA Office of Pesticide Programs

OPPTS		EPA Office of Prevention, Pesticides and Toxic Substances

PAD		Population Adjusted Dose

PAIRA		Pure Active Ingredient Radiolabelled

PCA		Percent Crop Area

PDP		USDA Pesticide Data Program

PHED		Pesticide Handler's Exposure Data 

PHI		Preharvest Interval

phr		Pounds Per Hundred

ppb		Parts Per Billion

PPE		Personal Protective Equipment

ppm		Parts Per Million

PRZM/EXAMS		Tier II Surface Water Computer Model  

Q1*	The Carcinogenic Potential of a Compound, Quantified by the EPA's
Cancer Risk Model

RAC		Raw Agriculture Commodity

RED		Reregistration Eligibility Decision

REI		Restricted Entry Interval

RfD		Reference Dose

RQ		Risk Quotient

SCI-GROW		Tier I Ground Water Computer Model

SAP		Science Advisory Panel

SF		Safety Factor

SLN		Special Local Need (Registrations Under Section 24©) of FIFRA)

TGAI		Technical Grade Active Ingredient

TEP		Typical End-Use Product

USDA		United States Department of Agriculture

UF		Uncertainty Factor

WPS		Worker Protection Standard

V. APPENDICES  SEQ CHAPTER \h \r 1 Appendix A. Application and Specific
Use Information for Zinc Borate



Use Site	Formulation	Method of Application	Application Rate/ No. of
applications	Use Limitations

Materials preservatives

Plastic products	Manufacturing setting,

crystalline powder:

1624-120

73032-1

74981-1

75630-1	Closed and open loading	Add at a  rate of  0.5 – 4% of product
by weight (no more than 8% of product by weight)	For interior
applications such as PVC carpet backing, wall coverings, auto
upholstery, shower curtains, and urethane mattresses,

For exterior applications, such as polyethylene wire and cable, PVC
tenting and awnings, acrylic roof coatings.

Composites treated with product are not suitable for ground contact.

Not for Food or Drug Use.



	For interior applications a loading of 3-20 phr of product is
recommended

For exterior applications 3-30 phr is recommended

	Rubber products	Manufacturing setting, crystalline powder:

1624-120	Closed and open loading	For interior applications a loading of
3-20 phr of product is recommended

For exterior applications 3-30 phr is recommended	For interior
applications such as PVC carpet backing, wall coverings, auto
upholstery, shower curtains, and urethane mattresses,

For exterior applications, such as polyethylene wire and cable, PVC
tenting and awnings, acrylic roof coatings.

Composites treated with product are not suitable for ground contact.

Not for Food or Drug Use.

Coatings	Manufacturing setting, crystalline powder:

1624-120

73032-1

74981-1

75630-1

	In can preservative	Add at a  rate of  0.5 – 4% of product by weight
(no more than 8% of product by weight)	

Not for Food or Drug Use.



	0.25-2.5lb A.I./gal. of product

	Wood preservatives (for wood composite materials used in above ground
applications)

Wood

(Siding, roofing, millwork, sheathing, subflooring)	Manufacturing
setting, 

powder:

1624-120

73032-1

74981-1

75630-1	Closed and open loading	Add at a  rate of  0.5 – 4% of product
by weight (no more than 10% of product by weight)	Composites treated
with product are not suitable for ground contact

Not for Food or Drug Use.



Appendix B. Toxicity Guideline Study Justifications

Guideline	Study Title	Practical Utility of the Data

870.2600	Dermal sensitization in guinea pigs	1)  What is the value of
the study?

The Agency does not have adequate data to assess potential dermal
sensitization for zinc borate since previous studies were classified as
unacceptable for regulatory purposes.

 

2)  How would the data be used?

This data will be used to determine whether zinc borate is a dermal
sensitizer and the hazard information obtained from this study could
impact product labeling and risk assessment conclusions.

3)  How could the data affect the risk assessment?

The study would identify zinc borate a dermal sensitizer or
non-sensitizer.  If dermal sensitization occurs, this study may provide
the dermal dose level that causes sensitization. If the study identifies
zinc borate as a dermal sensitizer, the Agency may require additional
hazard statements for labeling purposes.

4)  What is triggering the need for this data?

This study is a requirement of registration and the submitted studies
were unacceptable based on previous data evaluation reviews.



870.1300	Acute inhalation test in rats	1)  What is the value of the
study?

The Agency does not have adequate data to assess the potential effects
for zinc borate which could occur as a result of exposure via the
inhalation route.  This study could provide conclusive data on the
potential acute inhalation toxicities from spraying paint and loading
powder in manufacturing settings.

2)  How would the data be used?

These data will be used to determine whether zinc borate causes
inhalation toxicities and the hazard information obtained from this
study could impact product labeling and risk assessment conclusions.

3)  How could the data affect the risk assessment? The results of this
study may change how risks are quantified.  The data would allow the
Agency to conclude more definitively whether or not there would be any
concerns for acute inhalation toxicity.

4)  What is triggering the need for this data?

This study is a requirement of registration and the submitted studies
were waived based on previous data evaluation reviews. However, the
paint use, in particular exposure to sprays and mists from use
applications, is triggering this data need.

870.3465	90-Day Inhalation Toxicity Study

(Rat)	1)  What is the value of the study?

The Agency does not have adequate data to assess the potential effects
for zinc borate which could occur as a result of exposure via the
inhalation route.  This study would provide conclusive data on the
potential toxicities via repeat inhalation exposures to zinc borate.  It
may also provide a toxicity endpoint applicable to risk assessment.

2)  How would the data be used?

The results of the study may change how risks are quantified.  These
data would allow the Agency to conclude more definitively whether or not
there would be any concerns for inhalation toxicity in the rat.  This
information would provide a more complete hazard characterization of
zinc borate with respect to potential risks to the U.S. general
population.

3)  How could the data affect the risk assessment?

The results of the study may change how risks are quantified.  It is
possible that the database uncertainty factor could be reduced or
removed, resulting in a different magnitude of the value of the endpoint
used for pesticide regulation.

4)  What is triggering the need for this data?

The difficulty in predicting real world human inhalation exposure with
limited data and in the absence of inhalation data or other alternative
information, such as SAR (structure-activity-relationship), surrogate
data, and/or weight-of-evidence to the Agency triggered the need for a
90-day (guideline) Inhalation toxicity study.  This study would allow
the Agency to adequately evaluate real world human exposure to zinc
borate particles based on how it is used (The OPPTS Guidelines require
an MMAD of 1-3 (m in inhalation toxicity studies of aerosols so that a
portion of the test article will reach the lungs). The exposure to
paints from sprays and mists are triggering the need for toxicological
data in order to conduct a risk assessment for zinc borate. 



Appendix C: Exposure Guideline Study Justifications



Guideline	Study Title	Practical Utility of the Data



875.1300 and

875.1400

(Applicator)	Inhalation Outdoor Exposure and Inhalation Indoor Exposure
Note:  Inhalation exposure data are needed for both residential and
occupational uses.  The selection of an outdoor versus an indoor site is
based on the high end exposure scenario (for inhalation the selection is
typically indoors).  In almost all cases, repeating an exposure study
for the same scenario outdoors and indoors is not necessary.

1) What is the value of the study?

The inhalation exposure route is very important for exposure scenarios
such as paint rollers and airless sprayers where aerosols would be
generated.  In addition, inhalation exposures from liquid pouring are
evident in exposure studies in the Pesticide Handlers Exposure Database
(PHED).  The significance of these exposures is directly affected by the
severity of the inhalation toxicological endpoint of concern.  At this
point in time, no toxicological data are available to assess the
inhalation risk. The existing Chemical Manufacturer Association (CMA)
data base and PHED for these scenarios are limited in scope for QA/QC
and number of monitoring units.  EPA presented the need for additional
handler exposure data to the January 2007 Science Advisory Panel (SAP)
as well as to the April 2007 Human Studies Review Board (HSRB) and both
groups agreed that additional data are warranted.

2) How would the data be used?

The inhalation exposure data would be used to assess the residential
short-term duration of painting with a paint brush/roller and an airless
sprayer.  For occupational uses, the inhalation exposure data would be
used to assess the short- and intermediate-term as well as pouring zinc
borate powders (e.g., poured into paint as a preservative in
manufacturing settings for rubber, plastic, wood composite, etc).

3) How could the data affect the risk assessment?

The inhalation exposure data would be used to determine the accuracy of
the inhalation risks to both residence and occupational workers.  If
risks warrant mitigation, the inhalation exposure data would provide the
types of mitigation necessary such as respiratory protection from
respirators or closed systems for commercial uses to potential removal
of uses from the label.

What is triggering the need for this data?

The criteria for the inhalation exposure data are based on the potential
for respiratory exposure from the labeled uses (e.g., airless sprayers)
and evidence of toxicity.  If no toxicological endpoints of concern were
identified, then the inhalation exposure data would not be needed.

875.1600

(Applicator)	Data Reporting and Calculations 	1) What is the value of
the study?

For all exposure studies this data need is needed to facilitate the
review of the data.

2) How would the data be used?

The study report and all raw data/calculations would be reviewed for the
adequacy of the data.

3) How could the data affect the risk assessment?

The data are needed to interpret the inhalation exposure data collected.

4) What is triggering the need for this data?

This data need is triggered if an exposure study is conducted.

875.1700

(Applicator)	Product Use Information	1) What is the value of the study?

Product use information is a description of how the product is actually
applied; it is not a field study.  A description of how this product is
used would provide for a comprehensive realistic assessment of its
potential applications.

2) How would the data be used?

The description of the application techniques would be used to define
the exposure scenarios to be assessed in the risk assessment.

3) How could the data affect the risk assessment?

A complete description of product use would ensure that the risk
assessment is inclusive of the types of exposures occurring during
residential and occupational use.

What is triggering the need for this data?

The need for a risk assessment as needed under Registration Review would
require that the risk assessor understands how the product is applied.

875.2700

(Post Application)	Product Use Information	1) What is the value of the
study?

Product use information for the post application data need is a
description of what types of consumer products are treated; it is not a
field study.  A description of what types of consumer products are
treated, specifically what types of textiles, would provide for a
comprehensive realistic assessment of potential post application
exposures.

2) How would the data be used?

The listing of the end use consumer products would be used to define the
exposure scenarios to be assessed in the risk assessment.  For example,
if rubber and plastics are used for toys then a children’s exposure
scenario needs to be assessed.  However, if the treated rubber and
plastic are limited to PVC pipes, shower curtains, etc., a post
application assessment may not be needed. 

3) How could the data affect the risk assessment?

A complete description of consumer products treated would ensure that
the risk assessment is inclusive of the types of exposures occurring
during residential use.

4) What is triggering the need for this data?

The need for a risk assessment as needed under Registration Review would
require that the risk assessor understands how the product is applied.



Appendix D. Environmental Fate Guideline Study Justifications



Guideline	Study Title	Practical Utility of the Data 

OPP 161-1	Hydrolysis	1) What is the value of the study?

Results from the hydrolysis study will indicate the stability and
persistence of zinc borate, indicating the potential for this chemical
to contaminate water discharged to WWTPs.  In aquatic effluents, WWTPs
may discharge directly to surface waters.  The Agency will address the
risks of concern.

2) How would the data be used?

Data would show/help in establishing chemical hydrolysis as a route for
degradation of a pesticide and to identify, if possible, the hydrolytic
products formed which may adversely affect non-target organisms and may
contaminate water and food source of aquatic organisms.

3) How could the data affect the risk assessment?

The results of hydrolysis data would indicate if zinc borate is
persistent or it degrades into degradation products which may adversely
affect nontarget organisms and may contaminate their food and water and
possibly soil.

4) What is triggering the need for this data?

Hydrolysis data is needed to conduct the fate assessment to support
indoor uses for zinc borate.

850.6800	Modified Activated Sludge, Respiration Inhibition	1) What is
the value of the study?

The modified activated sludge, respiration inhibition test would allow
EPA to identify antimicrobial pesticides which could harm microorganisms
found in biological wastewater treatment systems and would also help
establish correct concentrations for use in the ready biodegradability
test.

2) How would the data be used?

The data would be used to determine the potential of zinc borate to
directly harm the nontarget organisms and/or to microbial treatment
processes present in a WWTP and to determine suitable noninhibitory
concentrations of zinc borate to be used in biodegradability tests.

3) How could the data affect the risk assessment?

If the data shows that zinc borate is toxic to nontarget organisms
and/or to microbial process found in WWTPs then, the Agency may need
Tier II environmental fate data to evaluate potential adverse effects on
WWTPs.

4) What is triggering the need for this data?

Studies are needed to conduct environmental fate assessment and to
determine the potential exposure of zinc borate to waste water treatment
plants (WWTPs) (via effects on WWTP microbes).

835.1110	Activated Sludge Sorption Isotherm	1) What is the value of the
study?

The results from activated sludge sorption study would allow EPA to
assess the distribution of the antimicrobial among the solid, aqueous,
and vapor phases of WWTPs.  Specifically, this study identifies those
chemicals which sorb to sludge biomass. 

2) How would the data be used?

The data would be used to determine the sorption potential of zinc
borate to activated sludge biomass and in biological wastewater
treatment systems.

3) How could the data affect the risk assessment?

If zinc borate is not sorbed or biodegraded then, it would pass through
a biological treatment system unaffected and it would contaminate
surface and drinking waters and also have potential adverse effects to
nontarget organisms.

4) What is triggering the need for this data?

Studies are needed to conduct an environmental fate assessment and to
determine the sorption potential of activated sludge for the removal of
specific chemical compounds in biological wastewater treatment systems.

835.3110

	Ready Biodegradability	1) What is the value of the study?

The ready biodegradability study would enable the Agency to determine
the likelihood that the antimicrobial pesticide of biodegrading in
aquatic environments under aerobic conditions.

2) How would the data be used?

The results from the data would be used to determine the rate and extent
of aerobic biodegradation of zinc borate when it is released into
aquatic environments and would help establish if zinc borate is stable
or not stable under real environmental conditions.   

3) How could the data affect the risk assessment?

If the results shows low biodegradability then, zinc borate would occur
in significant quantities in WWTP effluents (water and biosolids) and in
environmental compartments (e.g., surface waters) such that potential
adverse effects to nontarget organisms, found in such environmental
compartments, may occur.

4) What is triggering the need for this data?

Data are needed to conduct environmental fate assessment and to
determine the ready biodegradability of zinc borate.

AWPA E11-06	Leachability of Wood Preservatives	1) What is the value of
the study?

The results from the wood preservative leaching study by AWPA E11-06
would allow EPA to measure the leaching rate of zinc borate from treated
wood composite materials such as siding, roofing, millwork, sheathing,
and subflooring.

2) How would the data be used?

The data would be used to determine the leachability of wood
preservatives expressed as a percentage of the original preservative
retention.  The amount of preservative leached is expressed as the ratio
of the preservative contained in the leachate to the total preservative
present.

 

3) How could the data affect the risk assessment?

If zinc borate is leached from the wood in large percentage then, it
would contaminate surface and drinking waters and also have potential
adverse effects to nontarget organisms.

4) What is triggering the need for this data?

Studies are needed to conduct environmental fate and ecological effects
assessments and to determine the leachability of wood preservatives
expressed as a percentage of the original preservative retention; and to
confirm that ion levels in the leachate would be of no toxicological
concern.



Appendix E: Ecological Guideline Study Justifications



Guideline	Study Title	Practical Utility of the Data:  



850.5400	Tier II green algae using

Selenastrum

capricornutum	1) What is the value of the study?

As part of a Tier I risk assessment, one indicator plant species is
tested for phytotoxicity.  This study would allow the Agency to
categorize zinc borate as toxic or non-toxic to plants.  If toxic,
additional higher tier plant tests would be needed.  An endangered
species assessment for endangered or threatened plants is not possible
without this study.

2) How would the data be used?

This study would be used to evaluate the toxicity of zinc borate to
non-target plants in terrestrial and aquatic ecosystems. 

3) How could the data affect the risk assessment? 

Adverse effects to non-target plants in terrestrial and aquatic
ecosystems may result in mitigation to protect species at risk. 
Mitigation might include reduced label dosages, neutralization of
effluents prior to discharge into water, restrictions on use in
sensitive ecosystems or where endangered species are present, or other
mitigation measures.

4) What is triggering the need for this data?

Increased concern from state regulators and the public to evaluate
impacts on WWTP operations, endangered species, and persistence in the
environment, since initial registration, have triggered the need for
this study.  Green algae are critical to ecosystem health and
productivity.



  Including potential effects on wastewater treatment plants (WWTPs).

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