2 

### Acetic Acid and Sodium Diacetate

– Table of Contents

I. Introduction

................................ ................................ ................................ .......................... 3

A. General Background

................................ ................................ ................................ .... 4

II. Scientific Assessments

................................ ................................ ................................ ......... 5

A. Human Health Assessment

................................ ................................ .......................... 5

B. Environmental Assessment

................................ ................................ ......................... 6

C. Endan gered Species Assessment

................................ ................................ ................. 6

D. Endocrine Disruptor Screening Program

................................ ................................ .. 7

III. Interim Registration Review Decision

................................ ................................ ............. 7

IV. Next Steps

................................ ................................ ................................ ........................... 83 I. Introduction

This document is the Environmental Protection Agency’s (EPA or the Agency) Interim Registration Review Decision for acetic acid and sodium diacetate and it discusses the public comment received concerning the Proposed Interim Registration Review Decision. This Interim Re gistration Review Decision is being issued pursuant to 40 CFR sections 155.56 and 155.58

. A registratio n review decision is the Agency’ s determination whether a pesticide meets, or does not meet, the standard for registration in the Federal Insecticide, Fu ngicide, and Rodenticide Act (FIFRA). The Agency may issue, when it determines it to be appropriate, a n interim registration review decision before completing a registration review. Among other things, the interim registration review decision may (1) requi re new risk mitigation measures ; (2) impose interim risk mitigation measures ; (3) identify data or information required to complete the review ; and (4) include schedules for submitting the required data, conducting new risk assessment s or revising preliminary assessments, and completing the registration review.

During the 60

- day public comment period for the Acetic Acid and Sodium Diacetate Proposed Interim Registration Review Decision , which opened on December 24, 2014, the Agency received one comment. The comment was submitted by the Center for Biological Diversity (CBD) and CBD commented that it agreed with the Agency’s finding for this chemical case regarding endangered species. Th e public comment in its entirety is located in the docket, EPA

- HQ

- OPP

- 2008

- 0016

.

Pursuant to 40 CFR S ection 155.50, EPA formally initiated registration review for acetic acid and sodium diacetate (case 4001 )

. Sodium diacetate is a salt of acetic acid. Th e following highlights significant events that have occurred during the registration review of acetic acid and sodium diacetate :

• March 26, 2008

– Publication of the Acetic A cid and S alts Summary Document for a 60

- day public comment period . The Summary Document included the preliminary w ork p lan (PWP) and was accompanied by the scoping document and problem formulation.

• August 21, 2008

- Final Work Plan (FWP) for acetic acid and sodium diacetate was signed

-- no public comments were received during the 6 0

- day comment period for the Acetic acid and S alts Summary Document

. The FWP did not modify the Summary Document

.

• January 2010

- Data Call

- In s (DCI) were issued for acetic acid ( GDCI

- 044001

- 28802 ) and its salt, sodium diacetate ( GDCI

- 044008

- 29025) . For acetic acid, p lant toxicity studies and an UV/absorption study were required. Only an UV/absorption study was required for sodium diacetate. The required studies were subsequently determined to not be needed for the acetic acid and sodium diacetate risk assessments and were waived

.

• December 24, 2014

- The preliminary human health and ecological risk assessment s , along with the Acetic Acid and Sodium Salts Proposed Interim Registration Review Decision
, were published for a 60

- day comment period. One comment was received from the Center for Biological Diversity . However, the comment did not affect the interim decision.4 Additional information about acetic acid and sodium diacetate , including this Interim Registration Review Decision

, can be found in EPA’s public docket

, EPA

- HQ

- OPP

- 20 08

- 0 016

, accessed at www.regulations.gov

.
A. General Background

The a cetic acid and salts case is composed of two different active ingredients: acetic acid (PC Code: 044001) and its salt, sodium diacetate (PC Code: 044008) . Acetic acid is registered for use as a preservative for post

- harvest stored grains and hay intended for livestock feed. Additionally, it is also registered for use as a non

- selective herbicide for control of broadleaf weeds and grasses. Vinegar is a solution of about 5% acetic acid in water. Both acetic acid and

s odium diacetate are fungicide s and bactericide s registered to control molds and bacteria. They

are app lied to hay to prevent spoilage and to silage as an aid in fermentation. Non

- pesticidal uses include use in food as a flavoring agent, or as a preservative. In water, sodium diacetate dissociates into an acetic acid and sodium acetate solution. There ar e residential uses for the herbicidal products containing acetic acid; there are no residential uses for sodium diacetate. A Reregistration Eligibility Decision (RED) was completed in September 1991 for sodium diacetate, since there were no registered use s of acetic acid at that time. Sodium diacetate was also the subject of a Tolerance Reassessment Eligibly Decision (TRED) in 2002, for the purpose of reassessing its exemption from the requirement of a tolerance.

II. Scientific Assessments

A summary of the Agency’s e cological risk assessment s , Science Review in Support of Registration Review for Acet ic Acid ( October 7 , 2014) and Registration Review

– Qualitative Ecological Risk Assessment and Effects Determination of Sodium Diacetate (April 25, 2012)

, is presented below

. The Agency determined that previous human health assessments for acetic acid and sodium diacetate were sufficient for registration review and no human health risks of concern were identified

. Additional information about the human health risks is found in the Human Health Problem Formulation (November 28, 2007) in the Acetic Acid and Salts Summary Document (March 2008) . For the Summary Document and the actual ecological
assessment s , see the acetic acid and sodium diacetate public docket ( EPA

- HQ

- OPP

- 2008

- 0016 ) accessed at www.regulations.gov

.
A. Human Health Risk Assessment

No risks of concern were identified from previous reviews of acetic acid and sodium diace tate. There are no significant adverse effects to the general public or any population subgroup from consumption of residues of acetic acid or sodium diacetate resulting from pesticidal uses.

Acetic acid is registered as a 6% active ingredient liquid formulation (approximately the same concentration of vinegar , which is 5% acetic acid in water ) for consumer use as a home garden non

- selective herbicide in non

- food crop areas. No adverse effects are expected on humans from the use of these products acco rding to label directions. There are no residential uses for sodium diacetate.5 A qualitative occupational exposure assessment for both acetic acide and sodium diacetate determined there are no risk concerns for handlers, including mixers, loaders, and applicators, or from post

- application exposure. In addition, there are no adverse effects from aggregate exposure to sodium diacetate or acetic acid.

Food Tolerances

Acetic acid and sodium diacetate are exempt from the requirement of a tolerance when used post

- harvest on grains and hays (40 CFR 180.1258 (a) and 180.1058 , respectively ) , and unintentional residues of acetic acid in non

- target plants as a result of its herbicidal use are also exempt from the requirement of a tolerance (40 CFR 180.1258(b)). Both acetic acid and sodium diacetate are affirmed as generally recognized as safe (GRAS) by the United States Food and Drug Administration (FDA) (21 CFR 184.1005 and 21 CFR 184.1754). There are no CODEX maximum residue limits established for acetic aci d. There are no harmonization issues. No additional changes are necessary for the tolerances for acetic acid and sodium diacetate at this time.

B. Environmental Assessment

For sodium diacetate, t he Agency conclude d in the Registration Review

– Qualitative Ecological Risk Assessment and Effects Determination of Sodium Diacetate (April 25, 2012) that , consistent with the conclusions of previous risk assessments, registered uses of sodium diacetate based on label directions should not result in unr easonable risks to non

- target organisms

, including a “no effect” characterization for federally listed threatened or endangered species. T he Agency reached this conclusion because of the low toxicity of sodium diacetate, and because the use of sodium diac etate to cure hay and silage should not result in a feasible route of exposure to non

- target organisms.

For acetic acid, t he Agency indicated in the initial problem formulation that the use of acetic acid to cure hay and silage, as with sodium diacetate, should not result in unreasonable risks to non

- target organisms, including a “no

- effect” characterization for federally listed threat ened and endangered species. The Agency assessed the use of acetic acid as an herbicidal horticultural vinegar in the risk assessment, Acetic Acid: Science Review in Support of the Registration Review for Acetic Acid. (October 7, 2014). This assessment con cluded that registered uses of acetic acid based on label directions should also not result in unreasonable risks to non

- target organisms, including a “no effect” characterization for federally listed threatened or endangered species.

Risk to Terrestrial Animals

Acetic acid was seen to be practically non

- toxic to terrestrial mammals in acute studies, with no endpoint established at the highest dose tested. This is consistent with the FDA’s classification of acetic acid as a GRAS chemical. Because an end point could not be established at doses up to 11,700 mg/kg, the Agency concludes that acetic acid will not pose an acute risk to terrestrial mammals. The requirement for avian toxicity data for acetic acid had previous ly been waived. The Agency looked at the results of avian toxicity studies for comparable compounds6 such as peroxy acetic acid

. The Agency’s Peroxy RED (EPA 739 F 93 026, Dec. 1993) states that an avian acute dietary study on peroxy acetic acid showed that the compou nd was practical ly

non

- toxic (> 2,000 mg/kg) on a dietary basis to b obwhite quail. For the current assessment, t he toxicity data for acetic acid to mammals is used as a surrogate for birds , leading to a conclusion of no acute risk to birds.

In addition to acetic acid be ing practically non

- toxic in these toxicity tests, additional lines of evidence indicate that acetic acid should not pose acute or chronic risk to birds and mammals. First, acetic acid is a naturally occurring substance found in all plants, animals, and h umans. In addition, exposure to acetic acid during or after application of acetic acid is unlikely because of immediate human activity (ground application), followed by degradation of acetic acid by aerobic processes thereafter with a half

- life of about a day. Plants exposed to acetic acid quickly turn brown, thus reducing their food value, and the acrid smell/taste of ac et ic acid would act as a deterrent.

An acute contact toxicity study on honey bees that shows no toxicity from acetic acid exposure wit h an LD 50 > 50 ug/bee, suggesting low risk to insects. In addition, an acute exposure of 26,225 mg ai of acetic acid per hive showed no mortality in honey bees nor the varroa mites inhabiting the hive.

Risk to Terrestrial Plants

Acetic acid works as a n herbicide by foliar contact which results in rapid desiccation of treated weeds. In order to be efficacious, the applied product must drench the target plant. Non

target plants are not expected to be impacted because the use pattern includes only ground application using coarse spray nozzles that are calibrated to deposit large droplets directly on the target area. H ooded applicator equipment is used for localized spot treatment, minimizing any off

- site drift.

Risk to Aquatic Animals and Plants

The A gency has assessed risk of exposure of acetic acid to aquatic organisms and has concluded that the potential for exposure and risk is very low. At current labeled uses, risks to aquatic organisms from these uses are expected to be minimal, since cont amination of aquatic environments from runoff will only result in short

- term pH changes that will be counteracted by the natural buffering capacity of the water and soil. T his compound exhibits very low toxicity to fish, aquatic invertebrates

, and aquatic plants. Risk quotients calculated at the highest application using a Tier 1 aquatic exposure model are below the Agency’s level of concern for risk to non

- target aquatic organisms, as well as for aquatic endangered/threatened species

.

C. Endangered Species Assessment

T here is no reasonable expectation for registered use s of acetic acid and sodium diacetate to cause direct or indirect adverse effects to threatened and endangered species

. No adverse modification of critical habitat is expected from the use of acetic acid and sodium diacetate

. EPA has made a “no effect” determination under the Endangered Species Act (ESA) for all listed species a s well as a “no habitat modification” determin ation for all designated critical habitat s for7 the currently registered use s of acetic acid and sodium diacetate . The Agency has therefore concluded that consultation with the Fish and Wildlife Service and the National Marine Fisheries Service under ESA s e ction 7(a)(2) is not required. EPA anticipates conducting no further analysis of potential risks to endangered or threatened species, unless data or information are obtained during the Registration Review process that would indicate such an assessment woul d be needed to inform the Agency’s decision.

D

. Endocrine Disruptor Screening Program

EPA has developed the Endocrine Disruptor Screening Program to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen , or other such endocrine effects as the Administrator may designate.” Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and November 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals and published a second list of chemicals proposed for order issuance in the future. Acetic acid and salts were not among the group of 58 pesticide active ingre dients on the initial list nor are they proposed on the second list of chemicals to be screened under the EDSP

. Accordingly, as part of registration review, EPA will issue future EDSP orders/data call

- ins for registration review chemicals, including acetic acid and salts . For further information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, future chemical lists proposed for screening, the test guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/

. In the interim, EPA is making no human health or environmental safety findings associated with the EDSP screening of acetic acid and salts

. Before completing this Registration Review, the Agency will make an EDSP FFDCA section 408(p) determination.

III. Interim Registration Review Decision

The Agency is issuing a n I nterim Registration Review D ecision pursuant to 40 CFR S ections 155.56 and 155.58

. The Agency determined that previous human health assessments for acetic acid and sodium diacetate were sufficient for registration review and no human health risks of concern were identified. The Agency completed a comprehensive ecological risk assessment for the nonselective herbicide use of acet ic acid and a qualitative ecological risk assessment for sodium diacetate

, including an endangered species assessment. EPA has determined that use of acetic acid and sodium diacetate should not result in unreasonable risk to

non

- target organisms, including threatened and endangered species and their critical habitats, and concludes a “no effect” determination for the registered uses of acetic acid and sodium diacetate. N o mitigation measures are included in th is interim decision.

In accordance with 40 CFR Sections 155.56 and 155.58, the Agency is issuing this I nterim Registration Review D ecision document. Except for the EDSP component of the acetic acid and sodium diacetate registration review case, t he Agency has made the following I nterim Registration Review D ecision : (1) no additional data are required at this time ; and (2) no changes to the affected registrations or their labeling are needed at this time

. EPA has not identified any risks of concern to human health. EPA has determined that use of acet ic acid and sodium acetate8 should not result in any significant exposure or risk to non

- target organisms. As such, EPA concludes “no effect” determination under the Endangered Species Act (ESA) for all listed species a s well as a “no habitat modification” determination for all designated critical habitat s for the currently registered uses of acetic acid and sodium diacetate

IV. Next Steps

A Federal Register Notice will announce the availability of this Interim Registration Review Decision for acetic acid and sodium diacetate. A final decision on the acetic acid and salts registration review case will occur after an FFDCA section 408(p) EDSP determination has been mad e.