U. S. ENVIRONMENTAL PROTECTION AGENCY 

Washington, D.C. 20460 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

Date: April25, 2012 

Chemical: Sodium Diacetate 

PC Code: 044008 

~c_,~li)f\ -U:I-l 516'-1'1 

DP Barcode: D391552 

MEMORANDUM 

SUBJECT: Registration Review - Qualitative Ecological Risk Assessment and Effects 

Determination of Sodium Diacetate 

TO: 

FROM: 

THROUGH: 

Melanie Biscoe, Chemical Review Manager 

Anne Overstreet, Risk Manager 

Pesticide Re-evaluation Division (7508P) 

· ~;tr; l-f! ?-s-/1 ')____ 

Meghan Radtke, Ph:D., ~iologist ~· / , &: !fp . _ . HeZhong,Ph.D.,Bwlog1st · ~~ 4/-:v:r; 2/11/..-z..--

Environmental Risk Branch I 

Environmental Fate and Effects Division (7507P) 

£v;bl,~ Na~cy Andrews, Ph.D., Branch.Chie~ ~ ~ { ,v (~-- • ~ 

Sujatha Sankula, Ph.D., Lead Bwlog1st , ~· \ = ;..=---·· 

Environmental Risk Branch I 

Environmental Fate and Effects Division (7507P) 

The Environmental Fate and Effects Division (EFED) has conducted a qualitative evaluation of 

sodium diacetate as a part of the registration review process and concluded that the use of this 

compound, based on the label directions, should not pose an unreasonable risk to non-target 

organisms. Sodium diacetate is a sodium acid salt of acetic acid, which readily dissociates into 

acetic acid and sodium acetate. It is applied to hay (stored in bales) to prevent spoilage, to silage 

as an aid in fermentation, and to preserve the quality of animal feeds such as field com, alfalfa, 

sorghum, oats, and grasses that are stored in silos. It is also registered for use as a supplement to 

livestock/poultry feeds and dairy rations. Consequently, EFED concludes a "No Effect" 

determination for all currently registered uses of sodium diacetate for all non-target organisms. 

1 

1111111111 

2087245 
1

U. S. ENVIRONMENTAL PROTECTION AGENCY

Washington, D.C. 20460

 OFFICE OF 

CHEMICAL SAFETY AND

POLLUTION PREVENTION

Date: April 25, 2012

Chemical: Sodium Diacetate

PC Code: 044008

DP Barcode: D391552

MEMORANDUM

SUBJECT: Registration Review – Qualitative Ecological Risk Assessment and Effects 

Determination of Sodium Diacetate

TO: Melanie Biscoe, Chemical Review Manager

Anne Overstreet, Risk Manager

Pesticide Re-evaluation Division (7508P)

FROM: Meghan Radtke, Ph.D., Biologist

He Zhong, Ph.D., Biologist

Environmental Risk Branch I

 Environmental Fate and Effects Division (7507P)

THROUGH: Nancy Andrews, Ph.D., Branch Chief

Sujatha Sankula, Ph.D., Lead Biologist

Environmental Risk Branch I

Environmental Fate and Effects Division (7507P)

The Environmental Fate and Effects Division (EFED) has conducted a qualitative evaluation of 

sodium diacetate as a part of the registration review process and concluded that the use of this 

compound, based on the label directions, should not pose an unreasonable risk to non-target 

organisms. Sodium diacetate is a sodium acid salt of acetic acid, which readily dissociates into 

acetic acid and sodium acetate. It is applied to hay (stored in bales) to prevent spoilage, to silage 

as an aid in fermentation, and to preserve the quality of animal feeds such as field corn, alfalfa, 

sorghum, oats, and grasses that are stored in silos. It is also registered for use as a supplement to 

livestock/poultry feeds and dairy rations. Consequently, EFED concludes a “No Effect” 

determination for all currently registered uses of sodium diacetate for all non-target organisms. 
2

REGISTRATION REVIEW

ECOLOGICAL RISK ASSESSMENT AND EFFECTS 

DETERMINATION

Sodium Diacetate

CAS Number: 126-96-5

USEPA PC Code: 044008

 

PREPARED BY:

Meghan Radtke, Ph.D., Biologist

He Zhong, Ph.D., Biologist, 

Environmental Risk Branch 1

Environmental Fate and Effects Division

PEER REVIEW TEAM:

Faruque Khan, Ph.D., Senior Scientist

Sujatha Sankula, Ph.D., Lead Biologist

APPROVED BY:

Nancy Andrews, Ph.D., Branch Chief

Environmental Risk Branch 1

Environmental Fate and Effects Division

Office of Pesticide Programs
3

Table of Contents

List of abbreviated terms and symbols 4

Executive summary 6

Nature of stressor 6

Use information 6

Physical and chemical properties 6

Ecotoxicity data 8

Ecological risk conclusions 9

Introduction 11

Purpose of assessment 11

Problem formulation 12

Nature of regulatory action 12

Previous assessments 12

Stressor description 13

Use characterization and methods of application 14

Modification to registered labels 17

Ecosystems potentially at risk 17

Risk hypothesis 18

Analysis plan 18

Summary of environmental fate 19

Effects to organisms 20

Aquatic effects 20

Fish and aquatic invertebrates 20

Aquatic plants 22

Terrestrial effects 23

Birds, reptiles, and land-phase amphibians 23

Mammals 23

Terrestrial invertebrates 24

Terrestrial plants 24

Incident database review 25

Risk to non-listed and listed species 25

Indirect effects to listed species 26

Effects to critical habitat 26

Bibliography 28

ECOTOX papers 30

Appendix A 41
4

List of Abbreviated Terms and Symbols

% symbol for “percent”

> symbol for “greater than”

oC symbol for “degrees Celsius”

ai active ingredient

bw body weight

CI confidence interval

DP Data Package

EC50 50% (or median) effect concentration

EFED Environmental Fate and Effects Division

e.g. Latin exempli gratica (“for example”)

et al. Latin et alii (“and others”)

etc. Latin et cetera (“and the rest” or “and so forth”)

FIFRA Federal Insecticide Fungicide and Rodenticide Act

FQPA Food Quality Protection Act

i.e. Latin id est (“that is”)

kg kilogram(s)

Koc symbol for the organic carbon partitioning coefficient

LAA likely to adversely affect

lb ai/A pound(s) of active ingredient per acre

IC50 50% (or median) inhibition concentration

LC50 50% (or median) lethal concentration

LD50 50% (or median) lethal dose

LOC level of concern

MA may affect

mg milligram(s)

mg/kg milligrams per kilogram (equivalent to ppm)

mg/L milligrams per liter (equivalent to ppm)

MRID master record identification number

NASS National Agricultural Statistics Service

NAWQA National Water Quality Assessment

NE no effect

NLAA not likely to adversely affect

NMFS National Marine Fisheries Service

NOAA National Oceanic and Atmospheric Administration

NOAEC no observable adverse effect concentration

NOAEL no observable adverse effect level

OPP Office of Pesticide Programs

OPPTS Office of Prevention, Pesticides, and Toxic Substances
5

pH symbol for the negative logarithm of the hydrogen ion activity in an aqueous solution, 

 dimensionless

pKa symbol for the negative logarithm of the acid dissociation constant, dimensionless

ppm parts per million (equivalent to mg/L or mg/kg)

USDA United States Department of Agriculture

USEPA United States Environmental Protection Agency

USFWS United States Fish and Wildlife Service

Wt weight
6

Executive Summary

Nature of Stressor

The Agency has conducted a qualitative evaluation of sodium diacetate as a part of the 

registration review process and concluded that the use of this compound, based on the label 

directions, should not pose an unreasonable risk to non-target organisms. Sodium diacetate is a 

sodium acid salt of acetic acid, which readily dissociates into acetic acid and sodium acetate. 

Acetic acid is the active moiety of sodium diacetate, which acts as fungicide and bactericide to 

control molds and bacteria by temporarily changing the local acidity. Acetic acid is also a 

naturally occurring chemical in plants and animals and an integral part of the Kreb’s cycle, 

forming adenosine-5-triphosphate (ATP) for energy. It is applied to hay (stored in bales) to 

prevent spoilage, to silage as an aid in fermentation, and to preserve the quality of animal feeds 

such as field corn, alfalfa, sorghum, oats, and grasses that are stored in silos. It is also registered 

for use as a supplement to livestock/poultry feeds and dairy rations. 

Application rates of sodium diacetate for hay and grain preservation are dependent upon the 

moisture content of the grains at the time of storage; application rates are 2 to 3 lb ai/ton of 

feed/hay. Application is usually not recommended at moisture contents above 25% (hay), 35% 

(high moisture ensiled corn) and 70% (silage). For dairy rations, the maximum application rate 

is 2 lb ai/ton.

Use Information 

Sodium diacetate is applied to crops post harvest. For baled hay preservation, application occurs 

at the time of baling in the field. Bales are then either stored outside, covered in plastic, or 

moved to sheds until needed. As a feed supplement for poultry, livestock, and dairy rations, 

sodium diacetate is added directly to the feed, either during the grinder/mixer stage or as a top 

dressing (dairy rations only). Lastly, sodium diacetate can be used for the preservation of 

processed corn, hay, sorghum, oat, and grass silages that are to be stored in a conventional 

upright, oxygen limiting pit and bunker silo. These applications occur at the time of chopping or 

at the blower when the silage is being loaded into the silo.

Physical and Chemical Properties

Sodium diacetate (CH3COONaCH3COOH) is described as a 1:1 mixture of sodium acetate and 

acetic acid, and is stable at ambient temperature. It is a white, hygroscopic, crystalline solid 

having an odor of acetic acid. The pH in a 10% (w/v) solution is 4.5-5.0 and gives positive tests 

for acetate and sodium. The molecular weight is 143.1 g/mole and the melting point is 150.55o C

(Table 1). It is readily soluble in water (1g/ml), slightly soluble in alcohol, and insoluble in ether 

(USEPA 1991). One gram of sodium diacetate is soluble in about 1 ml of water, liberating its 

major degradates – acetic acid (CH3COOH) and sodium acetate (CH3COONa). Acetic acid is 
7

also registered as a non-selective herbicide for control of broadleaf weeds and weed grasses to 

residential, golf courses, non-crop, right of way and industrial land sites (USEPA 2008). 

Acetic acid is a naturally occurring compound in plants and animals with a fundamental role in 

cell metabolism, particularly in the tricarboxylic cycle (Kreb’s cycle). At 25 oC, the solubility of 

acetic acid is 1.00E-06, the vapor pressure is 15.7 mm Hg, the Henry’s Law Constant is 1.00E07 atm-m3

/mole and the pKa dissociation constant is 4.76 (TOXNET) (Table 1). As acetic acid 

enters the tricarboxylic cycle, the acetyl molecule is broken down and serves as a source of 

energy transformed into ATP. In contrast, the anabolic production of fatty acids in plants and 

animals also involves the incorporation of two carbon acetyl molecules; however, when acetic 

acid is sprayed on terrestrial plants, it disrupts the integrity of the cell membrane and results in 

leakage of cellular fluids, causing the plant to dry out. Acetic acid has toxic effects on the 

central nervous system and kidneys (Clayton and Clayton 1982). Acetic acid is a weak acid and 

capable of affecting local pH. 

The by-products from environmental degradation of acetic acid are dependent on redox potential 

(Lindsay 1979). The estimated half-lives of acetic acid are about 17.3 days in soil and 8.7 days 

in water (EPI Suite 4.1). In oxic and suboxic environments, CO(g), HCOO-, and C2O4- are 

transient degradation products with eventual formation to CO2. Ethane (C2H4) formation occurs

only at extremely low redox conditions. Under anoxic conditions, methane is produced from 

acetic acid. Another major degradate, sodium acetate, produces sodium cations and acetate 

anions. The sodium cations may combine with other reactive materials in the soil. Below are 

the two main reactions for acetic acid/acetate anion degradation:

Aerobic/Suboxic Conditions: CH3COO- + 2H2O-------- 2 CO2 + 8e- + 7H+ log Ko = -9.64

Anaerobic Condition: CH3COO-+8e-+9H+---------------2CH4(g) + 2H2O log Ko = 36.19

Table 1. Physical and Chemical Properties of Sodium Diacetate and Acetic Acid (Major 

Degradation Product).

Parameter Value Reference

Sodium Diacetate (Parent)

Chemical Name Sodium Diacetate MRID 2058971

CAS Number 126-96-5 TOXNET

Molecular Formula CH3COONaCH3COOH MRID 2058971

Molecular Weight 143.1 g/mole TOXNET

SMILES Code C(O)(=O)C.C(C)(=O)[O-].[Na+] TOXNET

Melting Point (oC) 150.55 EPI Suite (v 4.10)

Boiling Point (oC) 424.96 EPI Suite (v 4.10)

Vapor pressure (25°C) 1.08 x 10-7 mm Hg @ 25oC EPI Suite (v 4.10)

Henry’s Constant 9.27x 10-9atm m3 mole-1 EPI Suite (v 4.10)

Solubility (25

oC) 1kg/L MRID 2058971

Koc 1 ml/g (mean) EPI Suite (v 4.10)
8

Parameter Value Reference

Acetic Acid (Major degradate)

Chemical Name Acetic Acid MRID 2058971

CAS Number 64-19-7 TOXNET

Molecular formula C2H4O2 EPI Suite (v 4.10)

Molecular weight 60.5 g/mol EPI Suite (v 4.10)

SMILES Code O=C(O)C EPI Suite (v 4.10)

Melting Point (oC) 16.6 TOXNET

Boiling Point (oC) 117.9 TOXNET

Vapor pressure (20/25°C) 15.7 mm Hg @ 25oC TOXNET

Henry’s Law Constant 1.0 x 10-7 TOXNET

Solubility (25

oC) 1.0 x 106 mg/L TOXNET

Koc 1 ml/g (mean) EPI Suite (v 4.10)

Ecotoxicity Data

One registrant-submitted study is available for sodium diacetate. A rat acute oral toxicity study 

demonstrated an LD50 of 5600 mg ai/kg, classifying the chemical as practically non-toxic to 

mammals. An open literature search did not yield any additional data specifically for sodium 

diacetate. 

Several registrant-submitted and open literature studies are available for sodium diacetate 

degradates – acetic acid and sodium acetate. These studies present a relatively benign picture of 

the two degradates. Acute data for freshwater fish (MRID 48770801), freshwater mollusks

(Cairns et al. 1976), estuarine/marine fish (Locke et al. 2009), and estuarine/marine invertebrates

(Locke et al. 2009) all classify acetic acid as slightly toxic to practically non-toxic. Acetic acid 

is classified as slightly toxic to freshwater oligochaete worms (MRID 48770801) and freshwater 

invertebrates (MRID 48770802). For terrestrial insects, an acute exposure of 26,225 mg ai/hive 

showed no mortality in honey bees nor the varroa mites inhabiting the hive (van Engelsdorp et 

al. 2008). Toxicity data for freshwater vascular plants, non-target algae, and freshwater diatoms 

are IC50 = 549 mg ai/L, 4000 mg ai/L, and 74 mg ai/L, respectively. No toxicity studies were 

available for terrestrial plants, although Stopar (2008) reported necrosis and chlorosis on apple 

leaves that were exposed to acetic acid. This aligns with acetic acid’s registration as a nonselective herbicide (USEPA 2010, DP 367372).

Chronic exposure to sodium diacetate and its degradates is not expected, based on the short halflife of acetic acid. 

When the Reregistration Eligibility Document for sodium diacetate was published in 1991, it was 

determined that there was sufficient knowledge to conclude that sodium diacetate was “slightly 

toxic to practically non-toxic,” and a regulatory decision was made that no further studies were 

needed.
9

Ecological Risk Conclusions

Potential risks are expected to be minimal from the registered uses of sodium diacetate. For 

treatments that occur on the field, the risk of toxicological exposure to non-target plants and 

aquatic organisms from runoff is low. Very high concentrations of acetic acid (major degradate) 

would be necessary to change the pH of an aquatic system and thus cause toxic responses; this 

response is not expected from the labeled application rate. In addition, acetic acid is practically 

non-toxic to freshwater fish, estuarine/marine fish, estuarine/marine invertebrates, vascular 

plants, and non-vascular plants (USEPA 2010). Incidental acute exposure to terrestrial wildlife 

that use the outdoor-stored, non-covered bales of hay as a resource (e.g., food, shelter) is also 

low, given the short half life (the half life of acetic acid is approximately 17.3 days in soil and 

8.7 days in water). Sodium diacetate is practically non-toxic to birds and mammals; acetic acid 

is practically non-toxic to terrestrial insects and birds. For the feed fermentation and dairy ration 

uses, applications usually occur indoors or directly at the site of the silo. All treated feed that is 

used for livestock and poultry has the potential to be placed in the troughs of outdoor feedlots, 

but given the domestic surroundings (e.g., farm buildings, farm houses, animal houses), it is 

unlikely to come into contact with many non-target species; listed species are unlikely to 

frequent such built up areas. In short, even if an incidental exposure of sodium diacetate or 

acetic acid occurs through terrestrial or aquatic pathways, the potential effects are expected to be 

short lived, localized, and not likely to cause any adverse effects.

The following table lists the potential direct and indirect effects to listed species from use of 

sodium diacetate on grain/hay storage and feed (Table 2).
10

Table 2. Potential risks to non-listed and listed species associated with direct or indirect 

effects from the proposed application of sodium diacetate

Taxonomic 

Group

Effects Endpoint1 Direct Effects2Indirect Effects to Listed 

Species

NonListedListed Potential Indirect Effects 

from Direct 

Effect to:3

Aquatic vascular 

plants

Measures of biomass No No No Not applicable

Aquatic nonvascular plantsMeasures of biomass No No No Not applicable

Terrestrial plants Measures of biomass-NA4 No No No Not applicable

Freshwater 

vertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Estuarine/marine 

vertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Freshwater 

invertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Estuarine/marine 

invertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Mammals Acute oral dose: mortality

Sub-acute dietary: mortality 

and growth-NA

Chronic: growth and 

reproduction-NA

No No No Not applicable

Birds Acute oral dose: mortalityNA

Sub-acute dietary: mortality 

and growth

Chronic: growth and 

reproduction-NA

No No No Not applicable

Terrestrial 

invertebrates

Acute contact and oral: 

mortality

No No No Not applicable

1Abbreviations: NA = toxicity data not available

2Negligible exposures to non-target organisms from sodium diacetate registered uses being indoors 

or contained (no spray drift, runoff, spillage). Therefore, adverse effects are not expected.

3Direct effects to species may result in indirect effects to other species by changing availability of 

prey, habitat, and other factors important to survival and reproduction.

4Acetic acid is registered as a non-selective herbicide, so it is expected that if directly applied to 

non-target plants, there could be adverse effects; however, the usage on hay/silage/feed is not 

expected to come into contact with non-target plants.
11

Therefore, a “no effect” determination has been concluded for federally listed species for the 

registered uses of sodium diacetate on the preservation of hay, silage, and as a food supplement 

for livestock, poultry, and dairy cows.

Introduction

Purpose of Assessment

The purpose of this assessment is to evaluate the potential risk to populations of non-listed (i.e., 

not federally endangered or threatened) species, and endangered and threatened (listed) species 

from exposure to sodium diacetate and its degradates from its registered uses. Risks from direct 

and indirect effects are derived and evaluated in accordance with the risk assessment 

methodology described in the Agency’s Overview Document (USEPA, 2004). These risk 

findings are then used as part of an “effects determination” for listed species. The Agency will 

reach one of the following three conclusions regarding the potential for the registered sodium 

diacetate use on non-food crops to affect federally listed species:

 “No effect;”

 “May affect, but not likely to adversely affect;” or

 “May affect, and likely to adversely affect.”

If the results of the risk assessment show no indirect effects and the levels of concern (LOCs) are 

not exceeded for direct effects for the taxonomic grouping of a listed species (e.g., freshwater 

fish, small herbivorous mammal), a “no effect” (NE) determination is made, based on sodium 

diacetate’s use within the action area for that species. If, however, there is a potential for indirect 

effects and/or risk quotients exceed the listed species LOC values for direct effects for a given 

group, the Agency concludes a preliminary “may affect species” (MA) within the taxonomic 

group. The Agency then considers additional lines of evidence such as the geographical nature 

of the exposure, as well as more in-depth evaluations of the toxicological and ecological 

requirements to determine a rationale for a “not likely to adversely affect” (NLAA) or “likely to 

adversely affect” (LAA) determination.

Similarly, the Agency will reach one of the following conclusions regarding the potential for 

sodium diacetate’s uses to result in destruction of adverse modification of critical habitat:

 “No adverse modification of critical habitat;”

 “May affect primary constituent elements.”
12

The Agency uses the risk assessment analysis for direct effects to categories of biological 

resource requirements to draw conclusions about effects to primary constituent elements of 

critical habitat. The Agency is limited in a practical sense to those primary constituent elements 

of critical habitat that are of a biological nature. If the results of the risk assessment show that no 

LOC is exceeded for all taxonomic groups, a “no effect” (NE) determination for habitat 

modification is made. If an LOC is exceeded for one or more taxonomic groupings, the Agency 

then considers additional lines of evidence to determine the rationale for a “may affect primary 

constituent elements.” This evidence may include: the type and degree of effect on the 

taxonomic groups, expected resultant effects on biologically mediated environmental processes 

(e.g., increased sedimentation from loss of vegetation) as compared to baseline environmental 

conditions, co-occurrence of the action area with critical habitat, or the type of principle 

constituent elements associated with critical habitat for listed species in a taxonomic grouping.

A qualitative versus quantitative risk assessment for sodium diacetate was chosen based on two 

premises: 1) the “generally regarded as safe – GRAS” food safety designation as assigned by the 

Food and Drug Administration (21 CFR 184.1005); and 2) the absence of sodium diacetate 

toxicity data.

Problem Formulation

Nature of Regulatory Action

Under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), all pesticides distributed 

or sold in the United States generally must be registered by the United States Environmental 

Protection Agency (USEPA). To determine whether a pesticide can be registered, the USEPA 

evaluates its safety to non-target species based on a wide range of environmental and health 

effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act (FQPA), and 

EPA was mandated to implement a new program for the periodic review of pesticides –

registration review1. The registration review program is intended to ensure that, as the ability to 

assess risk evolves and as policies and practices change, all registered pesticides continue to 

meet the statutory standard of no unreasonable adverse effects to human health and the 

environment. 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 be used safely.

Previous Assessments

Sodium diacetate was assessed previously in the Reregistration Eligibility Document (USEPA 

1991). This document determined that the general knowledge of sodium diacetate’s use pattern 

and chemistry were sufficient to make environmental assessments. More specifically, the 

 

1 http://www.epa.gov/oppsrrd1/registration_review/
13

document highlighted that sodium diacetate is applied to post-harvest livestock feed crops that 

are primarily within farm facilities with limited environmental exposure. Exposure to aquatic 

environments from runoff events, if they occur, will only result in a short-term change to the pH 

that will be counteracted by the natural buffering capacity of the water. A 10 percent acetic acid 

solution would be needed to change the pH to 4.5 from 5.0, which is unlikely, given the use 

pattern. Sodium diacetate is the conjugate base of a weak acid, thus it is expected that the pH 

would remain relatively constant in a buffer solution of sodium acetate and acetic acid. 

Furthermore, sodium diacetate and its degradates are known to have low toxicity and are part of 

the normal function in metabolic pathways of animals (FASEB 1977). Thus, the risk to wildlife 

is deemed low.

Acetic acid, a major degradate, was assessed by the Biopesticide and Pollution Prevention 

Division (BPPD) (USEPA 2010, D367372) in 2010. Two products were considered – an 8 

percent acetic acid solution and a 20 percent acetic acid solution. The assessment indicated 

possible risk to birds, insects, and terrestrial plants at an application rate of 29.4 lb ai/A, four

applications per season. 

No other risk assessments were identified.

Stressor Description

Sodium diacetate is a sodium acid salt of acetic acid, which readily dissociates into acetic acid 

and sodium acetate in the presence of moisture. Acetic acid is the active moiety of sodium 

diacetate, which acts as a fungicide and a bactericide to control molds and bacteria by 

temporarily changing the local acidity. It dissociates into acetate, sodium, and hydrogen ions. 

The ions that are produced by the dissociation of the sodium diacetate molecule are normal 

components of plants, animals, and human foods. 

Acetates are common metabolic intermediates in living organisms and are formed during the 

metabolism of food substances. In particular, acetic acid is an integral part of the tricarboxylic 

acid cycle (Kreb’s cycle) and forms ATP for energy use in cells. Acetates and acetic acid have 

long been used safely without major adverse effects in both human and animal foods at moderate 

levels of consumption (FASEB 1997). The Food and Drug Administration lists acetic acid as a 

substance that is “generally recognized as safe” (GRAS) for use in food (21 CFR 184.1005). 

Acetic acid is commonly used for curing and pickling, flavoring, pH control, as a solvent 

vehicle, and boiler water additive. It is used in concentrations of up to 9% in relishes and 

condiments.

There are only two active registrations for sodium diacetate – Crop Cure and Crop Cure 2 – both 

registered by Domain, Inc. for post-harvest use on hay and silage (Table 3). It is applied to hay 

(stored in bales) to prevent spoilage, to silage as an aid in fermentation, and to preserve the 
14

quality of animal feeds such as field corn, alfalfa, sorghum, oats, and grasses that are stored in 

silos. It is also registered for use as a supplement to livestock/poultry feeds and dairy rations. 

Acetic acid is registered as an herbicide (e.g., registration numbers 8655-11, 69836-1, 81936-1) 

and is being assessed separately by the Biopesticides and Pollution Prevention Division (BPPD). 

There are no active registrations for sodium acetate.

Use Characteristics and Methods of Application

Sodium diacetate is used for the preservation of baled hay (alfalfa, brome grass, clover, orchard 

grass, and timothy) that is to be stored for animal feed. Sodium diacetate prevents the spoilage 

of baled hay by inhibiting the growth of mold and microbes. It is also an aid for silage 

fermentation (processed corn, hay, sorghum, oat, and grass silages) and an additive to improve 

the palatability of livestock feeds. Treated silage may only be fed to livestock and poultry. 

Sodium diacetate can be applied in either a liquid or solid form. For hay preservation, solid-form 

sodium diacetate is applied to uniformly cover the hay during the baling process using a Gandy 

applicator (mechanism for evenly applying granules to hay or other commodities). For liquid 

applications, the sodium diacetate is diluted with water where it dissociates to form acetic acid. 

It should be uniformly applied at the time of baling using a pumping system with corrosion 

resistant parts. Application rates of sodium diacetate are dependent on hay moisture content; 

sodium diacetate should only be applied to hay with 15 to 25 percent moisture content.

As a livestock and poultry feed additive, sodium diacetate is mixed into the feed using a 

grinder/mixer. To achieve the appropriate mixture, grains (corn, soybean, wheat, barley, oats, 

etc.) and other dry ingredients (pre-mix diet supplements, vitamins, minerals, etc.) are first mixed 

together followed by the appropriate amount of sodium diacetate. After mixing well, high 

moisture ingredients (liquid vitamins, molasses, etc.) are incorporated; insufficient mixing may 

produce inconsistent mold inhibition. Sodium diacetate application rates are dependent upon the 

moisture content of the feed and should be applied to feeds containing 15 to 30 percent moisture.

As an aid in silage fermentation, sodium diacetate can be applied either as a solid or a liquid. 

For solid applications, a Gandy applicator (or equivalent) should be used to apply sodium 

diacetate at the time of chopping or at the blower when the silage is being loaded into the silo. 

The timing for liquid applications is the same, but a liquid applicator should be used. 

Application rates of sodium diacetate are dependent on silage moisture content (Tables 4 and 5). 

For corn, hay, grass, oat, and sorghum silage, the moisture content should be 50 to 70 percent; 

for high moisture ensiled corn, the moisture content should be 25 to 35 percent.

As an additive to dairy rations, sodium diacetate can be mixed into the feed or offered as a top 

dressing. When mixed into the feed, sodium diacetate is added after the other dry ingredients, 
15

but before the high moisture ingredients. When applied as a top dressing, it is sprinkled over the 

feed shortly before offering to livestock.

 

Table 3. Current sodium diacetate registrations

Registration Name 

(Registration Number)

Company Active 

Ingredient 

Uses

Crop Cure (32240-2) Domain, Inc. 50% Preservation of baled hay (alfalfa, 

brome grass, clover, orchard grass, and 

timothy) to be stored for the feeding 

season

Crop Cure 2 (32240-6) Domain, Inc. 80% For the preservation of baled hay 

(alfalfa, brome grass, clover, orchard 

grass, and Timothy) to be stored for the 

feeding season; improvement of 

palatability in livestock feeds (beef, 

swine, poultry, dairy cows); and aid in 

silage (processed corn, hay, sorghum, 

oat, and grass) fermentation

Table 4. Listing of label uses, application rates, form and equipment for sodium diacetate

Use Site Max. Rate per 

Application

(Registration 

Number)

Number of 

Applications

Form Application 

Equipment/Type

Hay – alfalfa, brome 

grass, clover, 

orchard grass, and 

timothy

2 lb ai/ton of hay 

(liquid) (32240-6)

2.5 lb ai/ton of hay 

(solid) (32240-2)

Single application Liquid or 

solid

Pumping system 

(liquid)

Gandy applicator 

(solid)

Ground feeds – corn 

soybean, wheat, 

barley, oats, etc. 

(beef, swine, and 

poultry feeds)

3 lb ai/ton of feed 

(32240-2)

Single application Solid Livestock feed 

mixer/grinder

Silage fermentation 

– corn, hay, 

sorghum, oat, grass

3 lb ai/ton of silage 

(32240-2)

Single application Liquid or 

solid

Liquid applicator 

(liquid)

Gandy applicator

(solid)

Dairy ration – corn, 

soybean, wheat, 

barley, oats, etc.

2 lb ai/ton of feed 

(32240-2)

Single application Solid Mix in feed or 

top dressing to 

feed
16

The Biological and Economic Analysis Division (BEAD) did not have up-to-date usage 

information (Screening Level Usage Estimates of Agricultural Uses – SLUA) for sodium 

diacetate. Detailed information about the uses was provided following a screening of the labels 

in 2007. The labels have not undergone any changes in 5 years and the information is still 

relevant (Table 5).

Table 5. Label information for sodium diacetate

Use site Max. rate per 

app.

Feed type Form Application type

Alfalfa 0.1250 lb/cwt Terrestrial feed 

crop

Form not 

identified/solid

Soluble 

concentrate/solid

Spray/stored 

commodity nonfumigation

Clover 0.1250 lb/cwt Terrestrial feed 

crop

Form not 

identified/solid

Soluble 

concentrate/solid

Spray/stored 

commodity nonfumigation

Corn 

(processed/ground)

0.5000 gal/ton Indoor food Soluble 

concentrate/solid

Stored 

commodity non2 lb/ton Form not fumigation

identified/solid

Dairy animal feed 

(processed)

0.0156 lb/animal Indoor food Soluble 

concentrate/solid

Top dressing

3 lb/ton Stored 

commodity nonfumigation

Grass 

forage/fodder/hay

0.0250 gal/cwt Terrestrial feed 

crop

Soluble 

concentrate/solid

Stored 

commodity nonfumigation

0.1250 lb/cwt Form not 

identified/solid

Soluble 

concentrate/solid

Spray/stored 

commodity nonfumigation

Hay (silage) 0.0250 gal/cwt Terrestrial feed 

crop

Soluble 

concentrate/solid

Stored 

commodity non0.0500 lb/cwt Form not fumigation

identified/solid

Livestock feed 

(processed)

3 lb/ton Indoor food Soluble 

concentrate/solid

Stored 

commodity nonfumigation

Oats (processed) 0.5000 gal/ton Indoor food Soluble 

concentrate/solid

Stored 

commodity non1 lb/ton Form not fumigation

identified/solid

Poultry feed 

(processed)

3 lb/ton Indoor food Soluble 

concentrate/solid

Stored 

commodity non-
17

Use site Max. rate per 

app.

Feed type Form Application type

fumigation

Sorghum 

(unspecified)

0.0250 gal/cwt Terrestrial feed 

crop

Soluble 

concentrate/solid

Stored 

commodity non0.0500 lb/cwt Indoor food Form not fumigation

identified/solid

Timothy 0.1250 lb/cwt Terrestrial feed 

crop

Form not 

identified/solid

Soluble 

concentrate/solid

Spray/stored 

commodity nonfumigation

Abbreviations: cwt = hundred weight

Modifications to Registered Labels

There have been no substantial modifications to registered labels since the Problem Formulation 

was written (USEPA 2008, DP 344770).

Ecosystems Potentially at Risk

The registered uses of sodium diacetate are either indoor uses or outdoor uses that are isolated 

and relatively contained. For the feed fermentation and dairy ration uses, applications usually 

occur indoors or directly at the site of the silo. All treated feed that is used for livestock and 

poultry has the potential to be placed in the troughs of outdoor feedlots, but given the domestic 

surroundings (e.g., farm buildings, farm house, animal houses), it is unlikely to come into contact 

with many non-target species; listed species are unlikely to venture into such developed areas. 

For baled hay treatments that occur on the field, the risk of exposure from runoff is low; very 

high concentrations of acetic acid (major degradate) would be necessary to change the pH of an 

aquatic system and thus cause toxic responses. Incidental acute exposure to terrestrial wildlife 

using the bales of hay as a resource is also low, given the short half life (the estimated half-life of 

acetic acid is approximately 17.3 days in soil and 8.7 days in water). In addition, the available 

toxicity data for sodium diacetate, sodium acetate, and acetic acid indicate that these chemicals 

are practically non-toxic to mammals and slightly toxic to practically non-toxic to aquatic 

species. Given that exposure is expected to be negligible for both aquatic and terrestrial systems, 

it is not expected that the registered uses of sodium diacetate would pose any risk to threatened 

or endangered species.
18

Risk Hypothesis

For sodium diacetate, the following ecological risk hypothesis is being tested:

 Based on a qualitative review of the available information indicating negligible exposure 

to the terrestrial and aquatic environment, sodium diacetate will not pose an adverse risk 

to non-target terrestrial and aquatic organisms.

Analysis Plan

In Registration Review, pesticide ecological risk assessments will follow the Agency’s 

Guidelines for Ecological Risk Assessment and will be in compliance with the paper entitled, 

“Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U. S. 

Environmental Protection Agency” (USEPA 2004).

The focus of an ecological risk assessment is on both the toxic effects of a pesticide to non-target 

organisms and the potential routes of the pesticide’s exposure to non-target organisms. In 

addition to addressing a pesticide’s toxic effects and potential routes of exposure, an ecological 

risk assessment addresses the uncertainties associated with a pesticide’s risk to non-target 

organisms.

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to federally-listed threatened and/or endangered (listed) species from 

registered uses of sodium diacetate. This assessment will be conducted in accordance with the 

Overview Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered 

Species Consultation Handbook (US FWS/NMFS 1998). 

In the case of a nationwide risk assessment conducted under registration review, the action area 

will encompass the entire U.S. and its territories. The purpose of defining the action areas as the 

entire U.S. and its territories is to ensure that the initial area of consideration encompasses all 

areas where the pesticide may be used now and in the future, including the potential for off-site 

transport via spray drift and downstream dilution. Additionally, the concept of a nationwide 

action area takes into account the potential for direct and indirect effects and any potential 

modification to critical habitat based on measured ecological effects that are associated with a 

reduction in survival, growth, and reproduction, as well as the full suite of sub-lethal effects 

available in the effects literature.

It is important to note that the nationwide action area does not imply that direct and/or indirect 

effects and critical habitat modification are expected to or are likely to occur over the full extent 

of the action area, but rather to identify all listed species and critical habitat that may potentially 

be affected by the action. The Agency will use more rigorous analyses, including consideration 
19

of available land cover data, toxicity data, and exposure information, to determine areas where 

individual listed species and designated critical habitat may be affected or modified via 

endpoints associated with reduced survival, growth, or reproduction.

Since exposure to non-target organisms from sodium diacetate use is expected to be negligible, 

no aquatic or terrestrial ecosystem is expected to be potentially at risk from registered uses of 

sodium diacetate. Therefore, a quantitative risk assessment will not be performed, but rather risk 

to terrestrial and aquatic organisms will be qualitatively assessed, in which no estimated 

environmental concentrations (EECs) or risk quotient (RQ) values will be generated.

Summary of Environmental Fate

The environmental fate of sodium diacetate and its two major degradates, acetic acid and sodium 

acetate, is well known. Environmental loadings are attributable to natural (plants and animal 

materials) and anthropogenic (food additives, drugs, and related products) sources. In water, 

sodium diacetate dissociates into an acetic acid-sodium acetate solution. The decomposition of 

these two compounds is very well established in the chemical and biological literature. Acetic 

acid decomposes directly into CO2 and water. Acetic acid combines with metallic ions derived 

from other compounds in the soil to form acetate salts such as sodium acetate. In solution, 

sodium acetate produces sodium cations and acetate anions. The sodium cations may combine 

with other reactive materials in the soil. Acetate sorption is faster than its microbial uptake and 

utilization (Fisher and Kuzyakov 2010). The acetate anions will decompose to CO2 and ethane. 

CO2 is a common constituent of the atmosphere while ethane is a minor constituent in the 

atmosphere in many areas. Anions of the compounds undergo aerobically mediated 

mineralization in days to weeks, and completely degrade into CO2 and water. A recent study 

shows, at a concentration of 10 μmol/L, the acetate anion has a half-life of about 3 minutes in 

soil solution and the oxidation to CO2 is at a similar rate for the carbon atoms of both the –CH3 

and –COOH groups. However, the decomposition to CO2 for carbon from –CH3 decreased more 

strongly than carbon from –COOH at acetate concentrations that were greater than 100 μmol/L

(Fisher and Kuzyakov 2010). Appendix A shows the complete degradation pathways of sodium 

diacetate and its metabolites. 

Mobility of sodium diacetate, acetic acid, and sodium acetate is expected to be high, based on 

adsorption estimates (Koc = 1 ml/g, EPI 4.1). However, migration to ground water should be 

substantially mediated through biodegradation, volatilization, hydrolysis or through uptake and 

utilization within plant cells. Terrestrial organisms may be potentially exposed to acetic acid 

vapor following a rain event, as suggested by the high vapor pressure of acetic acid (15.7 mm 

Hg). With a pKa at 4.74, acetic acid will exist almost entirely in the ionized form at pH 5 – 9 

and therefore, volatilization from the moist soil surfaces may not be an important fate process 

(TOXNET). The toxicity of sodium diacetate and acetic acid is driven by the acetate anion with 
20

the cations playing a minor role. Sodium diacetate and acetic acid are not persistent in the 

environment based on the predicted value (Table 6). 

Table 6. Environmental fate of acetic acid (major degradate)

Parameter Value Reference

Hydrolysis 8.7 days EPI Suite (v 4.10)

Aqueous Photolysis (t1/2) 17.2 days EPI Suite (v 4.10)

Aerobic Soil Metabolism (t1/2) 17.3 days EPI Suite (v 4.10)

Anaerobic Aquatic Metabolism (t1/2) 77.9 days EPI Suite (v 4.10)

Effects to Organisms

Few sodium diacetate toxicity studies are available for non-target organisms. Given that the 

compound dissolves in water to become acetic acid and sodium acetate, EFED reviewed the 

effects of these degradates to non-target organisms. Data for sodium diacetate, sodium acetate, 

and acetic acid indicate these substances to be slightly toxic to practically non-toxic on an acute 

basis. Given that the exposure is expected to be negligible, it is unlikely that there would be any 

adverse effects to non-target organisms. The following is the summary of EFED’s review.

AQUATIC EFFECTS

Aquatic exposure to sodium diacetate and its degradates is expected to be negligible. While 

sodium diacetate runoff may occur in the form of its degradate, acetic acid (formed via

hydrolysis), it is unlikely that the weak acid will significantly alter the pH of an aquatic system 

or pose a potential hazard because of its short half-life (approximately 17.3 days in soil and 8.7 

days in water). 

No sodium diacetate toxicity studies are available for aquatic organisms, given that the 

compound dissociates, instantaneously into an acetic acid and sodium acetate solution; however, 

several submitted and open literature studies on the degradates have provided information. 

Fish and Aquatic Invertebrates

An acetic acid acute toxicity study on Daphnia magna reported a 48-h EC50 as 65 ± 9.0 mg ai/L, 

classifying acetic acid as slightly toxic to freshwater invertebrates (MRID 48770802). 

A second study examined the acute effects of acetic acid on several freshwater species: tilapia 

(Oreochromis mossambicus), a cladoceran (Moina micrura), and an oligochaete worm 

(Branchiura sowerbyi) (MRID 48770801). A 96-h LC50 and confidence interval are listed in 

Table 7 for each species. Fish exhibited whitish lesions on their skin and fins after a few hours 

of exposure to concentrations of 262.4 mg ai/L and higher. They also showed signs of 

respiratory distress (frequent surfacing, abnormal opercular movement, gasping, release of air 

bubbles from mouth, and loss of equilibrium). The oligochaete worms reacted by sharply coiling 
21

their bodies at the higher concentrations of acetic acid (the study was not specific about which 

concentrations). Their bodies gradually fragmented, resulting in death. Cladocerans were 

observed to exhibit decreased swimming activity before death.

Table 7. LC50 for freshwater fish, cladoceran, and worm exposed to acetic acid for 96

hours

LC50 and Confidence Interval (mg ai/L)

Fish 272.87 (268.99-276.75)

Cladoceran 163.72 (156.38-171.07)

Worm 14.90 (14.48-15.43)

The chronic effects of acetic acid on tilapia were examined in a 90-day outdoor study (MRID 

48770801). No mortality occurred during the test. There were significant differences between 

the control and various treatment levels for the following: food consumption, food conversion 

efficiency, specific growth rate, yield, percent increase in weight, fecundity, and maturity index. 

Table 8 provides the NOAEC values for the various parameters that were measured.

Table 8. NOAECs values for multiple parameters of freshwater tilapia fish exposed to 

acetic acid for 90 days 

NOAEC (mg ai/L)

Food consumption 1.26

Food conversion efficiency 1.47

Specific growth rate 1.47

Yield 1.47

Percent increase in weight 1.47

Fecundity 1.47

Male maturity index 1.26

Female maturity index 16.79

Cairns et al. (1976) conducted a study to measure the 48-h acute effects of acetic acid on two 

freshwater snail species (Goniobasis livescens and Lymnaea emarginata angulata) (Table 9). A 

limitation of the study is that the lake water used in the experiment was not tested to confirm the 

absence of additional contaminants, although the control performance was deemed normal. 

Furthermore, the Agency’s normal endpoint for acute toxicity effects on mollusks is 96 hours (a 

more conservative value) rather than 48 hours. 

Table 9. 48-h acute toxicity values for two species of freshwater snail exposed to acetic acid

48-h LC50 (mg ai/L)

Goniobasis livescens 460

Lymnaea emarginata angulata 320
22

Locke et al. (2009) documented the acute effects of acetic acid to two estuarine/marine species: 

threespine stickleback fish (Gasterosteus acucleatus) and the sand shrimp (Crangon 

septemspinosa) (Table 10). The results of this study should be interpreted with caution as the 

dose-response curves were very steep for both organisms (fish – 0% morality at 0, 32, and 100 

mg ai/L but 100% mortality at ≥320mg ai/L; shrimp – 0% mortality at 0, 5, and 500 mg ai/L, but 

100% mortality at ≥ 500 mg ai/L).

Table 10. Toxicity values for the threespine stickleback fish and the sand shrimp

96-h LC50 (mg ai/L) 96-h NOAEC (mg ai/L)

Threespine stickleback fish 178 100

Sand shrimp 158 50

Piola et al. (2010) tested the effectiveness of a 5% acetic acid solution (52,450 mg ai/L) to 

manage tunicates, algae, tubeworm, bryozoans, and other fouling organisms. This experiment 

demonstrated that acetic acid can be detrimental to marine/estuarine organisms at high 

concentrations. Likewise, Paetzold et al. (2008) reported the effects of 5% acetic acid on 

estuarine/marine amphipods and gastropods. The study showed that amphipods were much more 

sensitive to the concentrated acetic acid exposures than the gastropods. All of the amphipods 

were classified as “inactive” after 5 minutes and 90% of them were dead after 2-3 hours. In 

contrast, 70% of the gastropods were classified as “inactive” at the 5 minute observation period, 

but most had completely recovered by the 5 to 9 day observation period. The Agency concludes 

that high acetic acid concentrations (5%) are unlikely to be present in aquatic systems through 

runoff from the registered uses of sodium diacetate.

Aquatic Plants

BPPD used an algal (Scenedesmus quadricanda) toxicity threshold of 4000 mg ai/L in their risk 

assessment of acetic acid (USEPA 2010). Two studies were available that documented the 

effects of acetic acid on aquatic plants. Table 11 shows the effects of acetic acid on the regrowth of hydrilla (Hydrilla verticillata); the most sensitive IC50 is for dry weight at 549 mg ai/L

(MRID 48770803). Academy of Natural Sciences (1960) reported the effects of acetic acid on 

freshwater diatoms (Navicula seminulum var. hustedtii) with a 120-h LC50 of 74 ppm. 

Table 11. The effect of acetic acid on hydrilla

Characteristic IC50 (mg ai/L)

Shoot length 851

New shoots 675

Dry weight 549
23

TERRESTRIAL EFFECTS

Terrestrial exposure to sodium diacetate and its degradates is expected to be negligible. Several 

sodium diacetate applications occur in feed grinders/mixers, which are contained and usually 

located indoors. One use involves the application of sodium diacetate to silage as the grains are 

being loaded into the silos. The application is expected to occur in built-up areas of the farm 

resulting in low potential exposure to non-target species. The most likely environmental 

exposure pathway is through applications to hay during the baling process on the field. 

However, given the short half-life and practically non-toxic classification, it is unlikely that a 

non-target organism will be adversely affected. 

Birds, Reptiles, and Land-phase Amphibians

In a chronic avian toxicity study, turkey poults (50 days old) were exposed to sodium acetate in 

drinking water for 7 weeks (Adams et al. 1969). No mortalities occurred, but enlarged kidneys 

were observed in the sodium acetate treatment group at 6178 ppm. Therefore, a LOEL of 6178 

ppm was established for sodium acetate. Adjusting for sodium diacetate (two acetates for every

sodium), the LOEL is 3089 ppm.

Data were not available for reptiles or land-phase amphibians; thus, birds are used as a surrogate 

for these groups.

Mammals

A registrant-submitted rat acute oral toxicity study for sodium diacetate reported an oral LD50 of 

5600 mg ai/kg (USEPA 2008). This endpoint classifies sodium diacetate as practically non-toxic 

to mammals. Several other rat studies were available from the human health effects risk 

assessment in the RED (USEPA 1991). The dermal LD50 was reported as > 2000 mg ai/kg. An 

8-h inhalation study induced a slight petechial hemorrhage in the lungs. Sodium diacetate is an 

eye irritant, which is expected because of its dissociation into acetic acid (a weak acid) when 

coming into contact with water. An eye irritation study in rabbits induced chemosis and redness

and another rabbit study documented severe corneal necrosis with a 15% solution, but only trace 

injuries with a 5% solution. There was no dermal irritation on rabbits using a 50% solution.

A chronic study for the effects of sodium acetate (a degradate of sodium diacetate) on mice was 

available from the open literature (Kavlock et al. 1987). The study monitored pregnant mice, 

specifically maternal weight change and mortality, and neonatal weight change and mortality. 

No effects (including sub-lethal) were found at the limit dose tested, thus establishing a NOAEC 

of 1000 mg ai/kg-day for sodium acetate. Table 12 provides the mammalian toxicity summary 

for sodium diacetate and sodium acetate. Given that sodium diacetate contains two acetate 

molecules for each sodium ion, the estimated NOAEC for sodium diacetate is 500 mg ai/kg-day.
24

Table 12. Mammal toxicity information for sodium diacetate and sodium acetate

Toxicity Route Value

Sodium Diacetate

Acute oral 5600 mg ai/kg

Acute dermal > 2000 mg ai/kg

Acute inhalation Not determined

Eye irritation Corneal involvement clearing in 8-21 days

Dermal irritation No irritation

Skin sensitizer Not determined

Sodium Acetate

Chronic reproductive (NOAEC) 1000 mg ai/kg-day

The metabolic pathways in mammals for sodium diacetate, acetic acid, and acetate were 

documented. Acetic acid is readily absorbed from the gastrointestinal tract and from the lungs 

(FASEB 1977, Clayton and Clayton 1982). It is rapidly and naturally incorporated into the 

intermediary metabolism by most tissues of the body (Clayton and Clayton 1982). Acetate is 

completely utilized in oxidative metabolism or in anabolic syntheses. Isotope experiments have 

shown acetate to be used in the formation of glycogen, carbohydrate intermediates, 

phospholipids, and fatty acids, as well as in cholesterol and steroid synthesis (Clayton and 

Clayton 1982, Geigy 1970, FASEB 1977). In addition, it participates in the acetylation of the 

amines and may be converted to alanine by transamination and then incorporated into proteins of 

the plasma, liver, kidney, gut mucosa, muscle, and brain (Geigy 1970). It has been estimated 

that the rat forms acetate at the rate of one percent of its body weight per day (FASEB 1977).

Terrestrial Invertebrates

van Engelsdorp et al. 2008, tested the effectiveness of acetic acid as a fumigant to control varroa

mites in honey bee colonies. Varroa mites are a parasite and can greatly reduce honey bee 

colony size and productivity. Each hive was treated with 26,225 mg of acetic acid (50 mL of a 

50% acetic acid solution). No bee or varroa mite mortality was found in the hives treated with 

acetic acid. This experiment indicates that acetic acid is relatively non-toxic to terrestrial 

invertebrates.

Terrestrial Plants

Information is not available regarding the effects of sodium diacetate on terrestrial plants; 

likewise, information is limited for acetic acid’s effects. Acetic acid is registered as a nonselective herbicide by OPP. The most recent risk assessment for acetic acid (USEPA 2010, DP 

367372) describes the mode of action in plants as the disruption of the cuticle on the surface of 

plant leaves and stem, which results in a rapid desiccation and browning of the plant. The 

assessment indicates that to be efficacious, plants must be thoroughly drenched with the products 

(20% and 8% acetic acid) for effective control to occur. A rate of 29.4 lb ai/A/application, four 

applications per year was assessed. This resulted in potential risks to non-target birds, terrestrial 
25

insects, and plants. However, the application rates are far higher than the registered uses for 

sodium diacetate, making it unlikely that such risks would be present for sodium diacetate 

applications. Stopar (2008) reported phytotoxic effects in apple trees as a result of acetic acid 

applications for apple blossom thinning. The most common effects were the burning of leaf 

edges and partially stunted growth of young leaves; effects appeared a few days after spraying 

and lingered for 11 weeks. The effects were most pronounced at the 525 mg ai/L treatment 

level.

Incident Database Review

On February 23, 2012, a review of the Ecological Incident Information System (EISS, version 

2.1.1), which is maintained by the Agency’s Office of Pesticide Programs, and the Avian 

Monitoring Information System (AIMS), which is maintained by the American Bird 

Conservancy, indicated no incident reports for sodium diacetate and its major degradates – acetic 

acid and sodium acetate. In addition to the incidents recorded in EIIS, other incidents may have 

been reported to the Agency as aggregate counts of incidents occurring per product per quarter. 

Ecological incidents reported in aggregate reports include those categorized as “minor fish and 

wildlife” (W-B), “minor plant” (P-B), and “other non-target” (ONT) incidents. “Other nontarget” incidents include reports of adverse effects to insects and other terrestrial invertebrates. 

For sodium diacetate and its degradates, no incidents were contained in this database.

Risk to Non-Listed and Listed Species

Direct adverse effects based on survival, growth, and reproduction to terrestrial and aquatic nonlisted species from the use of sodium diacetate are not expected (Table 13). This is based on 

several lines of evidence:

 The registered uses of sodium diacetate are limited to either indoor uses or outdoor uses 

that are isolated and relatively contained. For the feed fermentation and dairy ration uses, 

applications usually occur indoors or directly at the site of the silo. All treated feed that 

is used for livestock and poultry has the potential to be placed in the troughs of outdoor 

feedlots, but given the domestic surroundings (e.g., farm buildings, farm house, animal 

houses), it is unlikely to come into contact with many non-target species; listed species 

are unlikely to venture into such developed areas. For baled hay treatments that occur on 

the field, the risk of exposure from runoff is low; very high concentrations of acetic acid 

(major degradate) would be necessary to change the pH of an aquatic system and cause 

toxic responses. Other terrestrial wildlife exposures via incidental use of baled hay in a 

field would also likely be limited and not result in the consumption of concentrations 

high enough to cause an acute toxic response. Therefore, the anticipated environmental 

concentrations for sodium diacetate are expected to be below levels that could be of 

toxicological significance to non-target terrestrial and aquatic organisms.
26

 The available toxicity data for sodium diacetate and its degradates – sodium acetate and 

acetic acid – indicate that these chemicals are practically non-toxic to mammals on an 

acute basis and slightly toxic to practically non-toxic to aquatic species. For terrestrial 

plants, acetic acid can cause phytotoxic damage (Stopar 2008), if applied in high enough 

concentrations (8-20%) and amounts (e.g., drenching the plant leaves). The amount of 

acetic acid that might be expected in runoff waters is lower and probably would not result 

in “drenching” the entire plant, thus avoiding any major effects. There is evidence that 

should phytotoxic damage occur, recovery would take place within 2 months of the 

exposure (Stopar 2008). Barring repeated acetic acid drenches, it is unlikely that there 

would be any long-lasting effects to non-target terrestrial plants. Toxicity data for 

aquatic plants indicate that some plants are more sensitive than others (diatoms versus 

algae); however, it is unlikely that high enough concentrations of acetic acid would 

concentrate in a water body to cause a toxic response. Therefore, even if terrestrial 

and/or aquatic species were to come into contact with sodium diacetate-treated grain, hay, 

or runoff water, direct exposure to it and its degradates at levels expected to cause effects

would be unlikely, based on its low toxicity and its degradation properties.

 Sodium diacetate dissociates into sodium acetate and acetic acid upon the addition of 

water. The half-life of acetic acid is approximately 17.3 days in soil and 8.7 days in 

water, indicating that the degradation is rapid. Acetic acid also is a normal component of 

metabolism in the human body and many other organisms. It plays an integral role in 

producing ATP during the Kreb’s cycle. Thus, it is not expected to adversely affect nontarget species.

Overall, the use of sodium diacetate is expected to have no effect to non-listed and listed 

terrestrial and aquatic organisms, based on survival, growth, and reproduction.

Indirect Effects to Listed Species

Since direct adverse effects are not expected for listed species based on survival, growth, and 

reproduction, indirect effects to terrestrial and aquatic listed species also are not expected.

Effects to Critical Habitat

No adverse modifications to critical habitat for any terrestrial or aquatic listed species are 

expected from the use of sodium diacetate. This is based on the same lines of evidence as 

presented above.
27

Table 13. Potential risks to non-listed and listed species associated with direct or indirect 

effects from the proposed application of sodium diacetate

Taxonomic 

Group

Effects Endpoint1 Direct Effects2Indirect Effects to Listed 

Species

NonListedListed Potential Indirect Effects 

from Direct 

Effect to:3

Aquatic vascular 

plants

Measures of biomass No No No Not applicable

Aquatic nonvascular plantsMeasures of biomass No No No Not applicable

Terrestrial plants Measures of biomass-NA4 No No No Not applicable

Freshwater 

vertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Estuarine/marine 

vertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Freshwater 

invertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Estuarine/marine 

invertebrates

Acute: mortality

Chronic: NOAEC growth & 

reproduction-NA

No No No Not applicable

Mammals Acute oral dose: mortality

Sub-acute dietary: mortality 

and growth-NA

Chronic: growth and 

reproduction-NA

No No No Not applicable

Birds Acute oral dose: mortalityNA

Sub-acute dietary: mortality 

and growth

Chronic: growth and 

reproduction-NA

No No No Not applicable

Terrestrial 

invertebrates

Acute contact and oral: 

mortality

No No No Not applicable

1Abbreviations: NA = toxicity data not available

2Negligible exposures to non-target organisms from sodium diacetate registered uses being indoors 

or contained (no spray drift, runoff, spillage). Therefore, adverse effects are not expected.

3Direct effects to species may result in indirect effects to other species by changing availability of 

prey, habitat, and other factors important to survival and reproduction.

4Acetic acid is registered as a non-selective herbicide, so it is expected that if directly applied to 

non-target plants, there could be adverse effects; however, the usage on hay/silage/feed is not 

expected to come into contact with non-target plants.
28

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van Engelsdorp, D., R. M. Underwood, and D. L. Cox-Foster. 2008. Short-term fumigation of 

honey bee (Hymenoptera: Apidae) colonies with formic and acetic acids for the control 

of Varroa destructor (Acari: Varroidae). Journal of Economic Entomology, 101(2): 

256-264.

FASEB. 1977. Evaluation of the health aspects of acetic acid, sodium acetate, and sodium 

diacetate as food ingredients. NTIS PB-274 670.

Fischer, H. and Kuzyakov, Y. (2010). Sorption, microbial uptake and decomposition of acetate 

in soil: transformations revealed by position-specific 14C labeling. Soil Biology & 

Biochemistry 42:186-192.

Geigy S. A., J. R. 1970. Documenta, Geigy., 7th ed. Basle; as cited in FAO/WHO World Health 

Organ. Techn. Rep. Ser. No. 539, 1974.

Kavlock, R. J., R. D. Short, Jr., and N. Chernoff. 1987. Further evaluation of an in vivo 

teratology screen. Teratogenesis, Carcinogenesis, and Mutagenesis, 7: 7-16.

Lindsay, W. 1979 Chemical Equilibria in Soils, Wiley Press. p. 376-383

Locke, A., K. G. Doe, W. L. Fairchild, P. M. Jackman, and E. J. Reese. 2009. Preliminary 

evaluation of effects of invasive tunicate management with acetic acid and calcium 

hydroxide on non-target marine organisms in Prince Edward Island, Canada. Aquatic 

Invasions, 4(1): 221-236.

MRID 48770802 Janssen, C. R., E. Q. Espiritu, and G. Persoone. 1993. Evaluation of the new 

“enzymatic inhibition” criterion for rapid toxicity testing with Daphnia magna. In: 

Soares, A., and P. Cukow (Eds.), Progress in Standardization of Aquatic Toxicity Tests, 

Lewis Publishers: 71-81.

MRID 48770801 Saha, N. C., F. Bhunia, and A. Kaviraj. 2006. Comparative toxicity of three 

organic acids to freshwater organisms and their impact on aquatic ecosystems. Human 

and Ecological Risk Assessment: An International Journal, 12(1): 192-202.

MRID 48770803 Spencer, D. F. and G. G. Ksander. 1995. Influence of acetic acid on regrowth 

of dioecious hydrilla from root crowns. Journal of Aquatic Plant Management, 33: 61-

63.
29

Paetzold, S. C., J. Davidson, D. Giberson. 2008. Responses of Mitrella lunata and Caprella 

spp., potential tunicate micropredators, in Prince Edward Island estuaries to acetic acid 

anti-fouling treatments. Aquaculture, 285: 96-101.

Piola, R. F., R. A. Dunmore, B. M. Forrest. 2009. Assessing the efficacy of spray-delivered 

‘eco-friendly’ chemicals for the control and eradication of marine fouling pests. 

Biofouling, 26(2): 187-203.

Stopar, M. 2008. Vegetable oil emulsions, NaCl, CH3COOH and CaSx as organically 

acceptable apple blossom thinning compounds. European Journal of Horticulture 

Science, 73(2): 55-61.

United States Environmental Protection Agency. 1991. Reregistration eligibility document 

sodium diacetate. Special Review and Reregistration Division, Office of Pesticide 

Programs, Washington, DC.

United States Environmental Protection Agency. 2004. Overview of the ecological risk 

assessment process in the Office of Pesticide Programs. Office of Pesticide Programs, 

Washington, DC.

United States Environmental Protection Agency. 2008. EFED problem formulation for acetic 

acid (PC 044001) and sodium diacetate (PC 04408) registration review. DP 344770. 

Environmental Fates and Effects Division, Office of Pesticide Programs, Washington, 

DC.

United States Environmental Protection Agency. 2010. Science review in support of the end use 

product, 81936-R Summer Set All Down Concentrate and Summer Set All Down 

Herbicide. Biopesticide and Pollution Prevention Division, Office of Pesticide Programs, 

Washington, DC.

United States Fish and Wildlife Service (USFWS) and National Marine Fisheries Service 

(NMFS). 1998. Endangered Species Consultation Handbook: Procedures for 

Conducting Consultation and Conference Activities Under Section 7 of the Endangered 

Species Act. Final Draft. March 1998.
30

ECOTOX Papers

Acceptable for EcoTox and OPP May 2011

Adams, A. W., West, J. L., and Kahrs, A. J. (1969). Some Effects on Turkeys of Nitrate in the 

Drinking Water. Poult. Sci. 48: 1222-1229.

EcoReference No.: 35559

Chemical of Concern: NACE,NaNO3; Habitat: T; Effect Codes: 

BCM,BEH,CEL,GRO,MOR,PHY; Code: LITE EVAL CODED (NACE,NaNO3).

Used qualitatively in the assessment.

Anderson, B. G. (1946). The Toxicity Thresholds of Various Sodium Salts Determined by the 

Use of Daphnia magna. Sewage Works J. 18: 82-87.

EcoReference No.: 2130

Chemical of Concern: 

As,AsO3Na,AsO4Na,BOR,BORON,BRA,CIT,CN,Halides,NACE,NACIO,NAI,Na2Cr2,

Na2P,Na3C,Na3P,NaBS,NaBr,NaCBN,NaCN,NaCO,NaCl,NaClO,NaCr,NaID,NaNO3,

NaOH,NaSO4,SBS,SFL; Habitat: A; Effect Codes: PHY; Code: LITE EVAL CODED 

(BOR,Halides,NACE,Na2Cr2,Na3C,NaBS,NaBr,NaCN,NaCl,NaID,NaNO3,NaOH,SBS,

SFL), NO CONTROL (BRA,CIT), NO EFED CHEM 

(AsO3Na,AsO4Na,BORON,Na2P,Na3P,NaCBN,NaCO,NaClO,NaCr,NaSO4), OK 

(As,CN).

Not used because the endpoint was not useful.

Anderson, B. G. (1944). The Toxicity Thresholds of Various Substances Found in Industrial 

Wastes as Determined by the Use of Daphnia magna. Sewage Works J. 16: 1156-1165.

EcoReference No.: 2171

Chemical of Concern: 

ACAC,AN,AlCl,AlKS,AlS,As,AsO4Na,BZO,Ba,CIT,CaCl2,CoCl,CrO4,CuCl,CuS,ETH

N,FeCl,FeCl3,FeRS,HCL,Halides,K2Cr2O7,KCl,KPM,LLA,MOL,NHCl,NHOH,NHSO

4,NaCBN,NaCO,NaCl,NaNO3,NaOH,NaSO4,OXAC,PL,SAAAS,SUA,ZnS; Habitat: 

A; Effect Codes: PHY; Code: LITE EVAL CODED 

(ACAC,BZO,CIT,CaCl2,CrO4,ETHN,FeRS,HCL,Halides,MOL,NHOH,NaCl,NaNO3,N

aOH,OXAC,SUA,ZnS), NO CONTROL (CuS), NO EFED CHEM 

(AN,AlCl,AlKS,AlS,AsO4Na,Ba,CoCl,FeCl,FeCl3,K2Cr2O7,KCl,KPM,NHCl,NHSO4,

NaCBN,NaCO,NaSO4,PL,SAAAS), NO ENDPOINT (CuS), OK (As,CuCl,LLA).

Not the lowest endpoint, test duration was 16 hours instead of 48 hours.

Barry, J. D. and Polavarapu, S. (2004). Feeding Activity and Attraction of Blueberry Maggot 

(Diptera: Tephritidae) to Protein Baits, Ammonium Acetate, and Sucrose. J. Econ. 

Entomol. 97: 1269-1277.
31

EcoReference No.: 87498

Chemical of Concern: NHAC; Habitat: T; Effect Codes: BEH; Code: LITE EVAL 

CODED (NHAC).

Test duration was too short.

Begum, S. J., Mohanachari, V., and Indira, K. (1984). Changes in Energy Fuels of Fish During 

Ammonia Stress. Environ. Ecol. 2: 286-289.

EcoReference No.: 119

Chemical of Concern: NHAC; Habitat: A; Effect Codes: BCM,GRO; Code: LITE 

EVAL CODED (NHAC).

Test duration was not 96 hours.

Bodega, G., Suarez, I., Boyano, M. C., Rubio, M., Villalba, R. M., Arilla, E., Gonzalez-Guijarro, 

L., and Fernandez, B. (1993). High Ammonia Diet: Its Effect on the Glial Fibrillary 

Acidic Protein (GFAP). Neurochem. Res. 18: 971-975.

EcoReference No.: 151921

Chemical of Concern: NHAC; Habitat: T; Effect Codes: ACC,BCM,BEH,GRO; Code: 

LITE EVAL CODED (NHAC).

Endpoints were not reported in units useful for the risk assessment.

Boyano-Adanez, M. C., Bodega, G., Barrios, V., and Arilla, E. (1996). Response of Rat Cerebral 

Somatostatinergic System to a High Ammonia Diet. Neurochem.Int. 29: 469-476.

EcoReference No.: 113073

Chemical of Concern: NHAC; Habitat: T; Effect Codes: BCM,GRO; Code: LITE 

EVAL CODED (NHAC).

Endpoints were not reported in units useful for the risk assessment.

Corsi, S. R., Geis, S. W., Bowman, G., Failey, G. G., and Rutter, T. D. (2009). Aquatic Toxicity 

of Airfield-Pavement Deicer Materials and Implications for Airport Runoff. Environ. 

Sci. Technol. 43: 40-46.

EcoReference No.: 115482

Chemical of Concern: KACE; Habitat: A; Effect Codes: GRO,MOR,POP,REP; Code: 

LITE EVAL CODED (KACE).

Endpoint was not useful for the risk assessment.

Dabrowska, H. and Sikora, H. (1986). Acute Toxicity of Ammonia to Common Carp (Cyprinus 

carpio L.). Pol. Arch. Hydrobiol. 33: 121-128.
32

EcoReference No.: 12711

Chemical of Concern: NHAC,NHCl,NHN,NHOH,NHS; Habitat: A; Effect Codes: 

MOR; Code: LITE EVAL CODED (NHAC,NHN,NHOH), NO EFED CHEM 

(NHCl,NHS).

Duration of the test was not 96 hours.

De Avila Fortes, M., Oliveira de Sousa, R., Schmidt, F., Costa de Oliveira, A., and Vahl, L. C. 

(2009). Calcium Effects on Acetic Acid Toxicity in Rice. Commun. Soil Sci. Plant Anal.

40: 2536-2544.

EcoReference No.: 151918

Chemical of Concern: ACAC; Habitat: A; Effect Codes: ACC,BCM,GRO; Code: 

LITE EVAL CODED (ACAC).

Endpoints were not reported in units useful for the risk assessment.

DeYoung, D. J., Bantle, J. A., Hull, M. A., and Burks, S. L. (1996). Differences in Sensitivity to 

Developmental Toxicants as seen in Xenopus and Pimephales Embryos. Bull. Environ. 

Contam. Toxicol. 56(1): 143-150.

EcoReference No.: 16432

Chemical of Concern: NACE; Habitat: A; Effect Codes: GRO,MOR; Code: LITE 

EVAL CODED (NACE).

The test was 120 hours in duration rather than 96 hours.

Dial, E. J., Hall, L. R., Romero, J. J., and Lichtenberger, L. M. (1996). Rats with Gastritis have 

Increased Sensitivity to the Gastrin Stimulatory Effects of Luminal Ammonia. 

Gastroenterology 110: 801-808.

EcoReference No.: 151841

Chemical of Concern: NHAC; Habitat: T; Effect Codes: BCM,BEH,CEL,GRO; Code: 

LITE EVAL CODED (NHAC).

Endpoints were not reported in units useful for the risk assessment.

Djian, C., Ponchet, M., and Cayrol, J. C. (1994). Nematocidal Properties of Carboxylic Acids 

and Derivatives. Pestic. Biochem. Physiol. 50: 229-239.

EcoReference No.: 96598

Chemical of Concern: ACAC,ADC,BZO,DBE,EP,FMA,GLYA,OXAC,PPA,SCA; 

Habitat: A; Effect Codes: MOR; Code: LITE EVAL CODED 

(ACAC,ADC,BZO,EP,OXAC,PPA,SCA), NO EFED CHEM (DBE,FMA,GLYA).

Endpoints were not reported in units useful for the risk assessment.

Fort, D. J., McLaughlin, D. W., Rogers, R. L., and Buzzard, B. O. (2003). Evaluation of the 
33

Developmental Toxicities of Ethanol, Acetaldehyde, and Thioacetamide Using FETAX. 

Drug Chem. Toxicol. (N.Y.) 26: 23-34.

EcoReference No.: 82000

Chemical of Concern: ACAC,ETHN,PCB; Habitat: A; Effect Codes: GRO,MOR; 

Code: LITE EVAL CODED (ACAC,ETHN), NO EFED CHEM (PCB), NO MIXTURE 

(PCB).

Study was evaluated, but classified as “invalid.”

Greer, L. and Dole, J. M. (2005). Defoliation of Woody Cut Stems with Preharvest, Less Toxic 

Chemical and Postharvest Environmental Methods. HortTechnology 15: 376-380.

EcoReference No.: 118123

Chemical of Concern: ACAC,DMP,EPH,NONA; Habitat: T; Effect Codes: CEL,PHY; 

Code: LITE EVAL CODED (ACAC,EPH,NONA), NO EFED CHEM (DMP).

Study was evaluated, but classified as “invalid.”

Heath, R. R., Epsky, N. D., Guzman, A., Dueben, B. D., Manukian, A., and Meyer, W. L. 

(1995). Development of a Dry Plastic Insect Trap with Food-Based Synthetic Attractant 

for the Mediterranean and Mexican Fruit Flies (Diptera: Tephritidae). J. Econ. Entomol.

88: 1307-1315.

EcoReference No.: 151926

Chemical of Concern: NHAC; Habitat: T; Effect Codes: BEH; Code: LITE EVAL 

CODED (NHAC).

Endpoints were not reported in units useful for the risk assessment.

Hernandez, C., Martin, M., Bodega, G., Suarez, I., Perez, J., and Fernandez, B. (1999). Response 

of Carp Central Nervous System to Hyperammonemic Conditions: An 

Immunocytochemical Study of Glutamine Synthetase (GS), Glial Fibrillary Acidic 

Protein (GFAP) and 70 kDa Heat-Shock Protein (HSP70). Aquat. Toxicol. 45(2-3): 195-

207.

EcoReference No.: 19920

Chemical of Concern: NH,NHAC; Habitat: A; Effect Codes: BCM,MOR; Code: LITE 

EVAL CODED (NHAC), NO EFED CHEM (NH).

Endpoint was not useful for the risk assessment.

Hirazawa, N., Oshima, S. I., Hara, T., Mitsuboshi, T., and Hata, K. (2001). Antiparasitic Effect 

of Medium-Chain Fatty Acids Against the Ciliate Cryptocaryon irritans Infestation in the 

Red Sea Bream Pagrus major. Aquaculture 198: 219-228.

EcoReference No.: 105099

Chemical of Concern: ACAC,CAC,CRA,NONA; Habitat: A; Effect Codes: 
34

MOR,PHY; Code: LITE EVAL CODED (ACAC,CAC,CRA,NONA).

Endpoint was not useful for the risk assessment.

Iishi, H., Tatsuta, M., Baba, M., Mikuni, T., Yamamoto, R., Iseki, K., Yano, H., Uehara, H., and 

Nakaizumi, A. (1997). Enhancement by Monochloramine of the Development of Gastric 

Cancers in Rats: a Possible Mechanism of Helicobacter pylori-Associated Gastric 

Carcinogenesis. J. Gastroenterol. 32: 435-441.

EcoReference No.: 151911

Chemical of Concern: NHAC,NaHCT; Habitat: T; Effect Codes: CEL,GRO,PHY; 

Code: LITE EVAL CODED (NHAC), NO EFED CHEM (NaHCT).

Endpoints were not reported in units useful to the risk assessment.

Insausti, A. M., Gaztelu, J. M., Gonzalo, L. M., Romero-Vives, M., Barrenechea, C., Felipo, V., 

and Insausti, R. (1997). Diet Induced Hyperammonemia Decreases Neuronal Nuclear 

Size in Rat Entorhinal Cortex . Neurosci. Lett. 231: 179-181.

EcoReference No.: 151927

Chemical of Concern: NHAC; Habitat: T; Effect Codes: CEL; Code: LITE EVAL 

CODED (NHAC).

Endpoint was not reported in units useful to the risk assessment.

Jester, J. V., Molai, A., Petroll, W. M., Parker, R. D., Carr, G. J., Cavanagh, H. D., and Maurer, 

J. K. ( 2000). Quantitative Characterization of Acid- and Alkali-Induced Corneal Injury 

in the Low-Volume Eye Test. Toxicol. Pathol. 28: 668-678.

EcoReference No.: 151823

Chemical of Concern: ACAC,NaOH; Habitat: T; Effect Codes: CEL,GRO,MOR,PHY; 

Code: LITE EVAL CODED (ACAC,NaOH).

Endpoints were not reported in units useful to the risk assessment.

Joseph, R. M., Devineni, A. V., King, I. F. G., and Heberlein, U. (2009). Oviposition Preference 

for and Positional Avoidance of Acetic Acid Provide a Model for Competing Behavioral 

Drives in Drosophila. Proc. Natl. Acad. Sci. U.S.A. 106: 11352-11357.

EcoReference No.: 151928

Chemical of Concern: ACAC,HCL,SUA; Habitat: T; Effect Codes: BEH,CEL,REP; 

Code: LITE EVAL CODED (ACAC,HCL,SUA), TARGET (HCL).

Duration of the experiment was not in accord with OPP Guidelines.

Kane, M. T. (1979). Fatty Acids as Energy Sources for Culture of One-Cell Rabbit Ova to Viable 

Morulae. Biol. Reprod. 20: 323-332.
35

EcoReference No.: 101665

Chemical of Concern: ACAC,OLEA,PPA; Habitat: T; Effect Codes: GRO; Code: 

LITE EVAL CODED (ACAC,PPA), NO EFED CHEM (OLEA).

Endpoint was not reported in units useful to the risk assessment.

Kavlock, R. J., Short, R. D. Jr., and Chernoff, N. (1987). Further Evaluation of an In Vivo 

Teratology Screen. Teratog. Carcinog. Mutagen. 7: 7-16.

EcoReference No.: 70488

Chemical of Concern: 

24D,24DXY,BMY,CBL,CCA,DM,EN,MRX,Maneb,NACE,PNB,PPCP,PPGL,Zineb; 

Habitat: T; Effect Codes: GRO,MOR,REP; Code: LITE EVAL CODED 

(24D,24DXY,BMY,CBL,DM,Maneb,NACE,PNB), NO EFED CHEM 

(CCA,EN,MRX,PPCP,PPGL,Zineb).

Evaluated as “qualitative” and used in the risk assessment.

Kazumori, H., Ishihara, S., Fukuda, R., and Kinoshita, Y. (2002). Time-Course Changes of ECL 

Cell Markers in Acetic Acid-Induced Gastric Ulcers in Rats. Aliment. Pharmacol. Ther.

16: 10-19.

EcoReference No.: 103295

Chemical of Concern: ACAC; Habitat: T; Effect Codes: BCM,CEL; Code: LITE 

EVAL CODED (ACAC).

Endpoints were not reported in units that were useful to the risk assessment.

Locke, A., Doe, K. G., Fairchild, W. L., Jackman, P. M., and Reese, E. J. (2009). Preliminary 

Evaluation of Effects of Invasive Tunicate Management with Acetic Acid and Calcium 

Hydroxide on Non-Target Marine Organisms in Prince Edward Island, Canada. Aquat. 

Invasions 4: 221-236.

EcoReference No.: 115787

Chemical of Concern: ACAC,CIT,HCL; Habitat: A; Effect Codes: GRO,MOR; Code: 

LITE EVAL CODED (ACAC), NO BACTERIA (HCL), NO CONC (CIT).

Evaluated as “qualitative” and used in the risk assessment.

Lynch, J. M. (1980). Effects of Organic Acids on the Germination of Seeds and Growth of 

Seedlings. Plant Cell Environ. 3: 255-259.

EcoReference No.: 101602

Chemical of Concern: ACAC,BZO,CIT,CaCO3,FMA,LLA,PPA,SCA; Habitat: T; 

Effect Codes: ACC,GRO,REP; Code: LITE EVAL CODED 

(ACAC,BZO,CIT,LLA,PPA,SCA), NO EFED CHEM (CaCO3,FMA).

Endpoints were not reported in units useful to the risk assessment.
36

Mayer, D. F., Lunden, J. D., Kovacs, G., and Miliczky, E. R. (2001). Field Evaluation of NonPesticide Chemicals as Honey Bee Repellents. In: L.P.Elzunces, C.Elissier, & G.B.Lewis 

(Eds.), Hazards of Pesticides to Bees, Institute National de la Recherche Agronomique, 

Paris, France 159-168.

EcoReference No.: 81711

Chemical of Concern: 3-

OCT,ACAC,ATC,BOR,BPRO,C6OH,C8OH,CAC,CASTOR,CBNDS,CF,CRA,CRV,C

WO,CaCO3,Captan,DBAC,DIC,DMDS,DMZ,DNS,EGL,ETHB,FAR,FTTCl,H3PO4,HT

S,IMC,IND,IPA,LIM,LIN,MAT,NCTN,OCRE,PCRE,PHTH,PL,PPCP,PPNOL,SFR,TM

L,nBUT; Habitat: T; Effect Codes: BEH; Code: LITE EVAL CODED 

(ACAC,BPRO,C8OH,CASTOR,CBNDS,CRA,CRV,CWO,Captan,DBAC,DMDS,DMZ,

DNS,EGL,ETHB,FAR,FTTCl,H3PO4,HTS,IMC,IND,LIM,MAT,NCTN,OCRE,PPNOL,

SFR,TML,nBUT), NO EFED CHEM 

(ATC,C6OH,CF,CaCO3,DIC,IPA,LIN,PHTH,PL,PPCP), NO EFFECT 

(BOR,CAC,PCRE,PL), NO MIXTURE (PHTH).

Duration of the experiment was not in accord with OPP Guidelines.

Mollet, P. (1976). Lack of Proof of Induction of Somatic Recombination and Mutation in 

Drosophila by Methyl-2- Benzimidazole Carbamate, Dimethyl Sulfoxide and Acetic 

Acid. Mutat. Res. 40: 383-388.

EcoReference No.: 104295

Chemical of Concern: ACAC,CBD; Habitat: T; Effect Codes: CEL,MOR; Code: 

LITE EVAL CODED (ACAC,CBD).

Duration of the experiment was not in accord with OPP Guidelines.

Paetzold, S. C., Davidson, J., and Giberson, D. (2008). Responses of Mitrella lunata and Caprella 

spp., Potential Tunicate Micropredators, in Prince Edward Island Estuaries to Acetic Acid 

Anti-Fouling Treatments. Aquaculture 285: 96-101.

EcoReference No.: 151824

Chemical of Concern: ACAC; Habitat: A; Effect Codes: BEH,MOR,POP; Code: 

LITE EVAL CODED (ACAC).

Evaluated as “qualitative” and used in the risk assessment.

Parkash, R. and Vandna (1994). Latitudinal Differentiation in Alcoholic Utilisation and 

Desiccation-Starvation Tolerance in Drosophila kikkawai Populations from India. 

Korean J. Genet. 16: 217-224.

EcoReference No.: 103292

Chemical of Concern: ACAC,ETHN,IPA,PPNOL,nBUT; Habitat: T; Effect Codes: 

MOR; Code: LITE EVAL CODED (ACAC,ETHN,PPNOL,nBUT), NO EFED CHEM 

(IPA).
37

Evaluated, but found to be “invalid.”

Pelacho, A. M., Martin-Closas, L., and Sanfeliu, J. L. I. (1999). In Vitro Induction of Potato 

Tuberization by Organic Acids. Potato Res. 42: 585-591.

EcoReference No.: 101664

Chemical of Concern: ACAC,HCL,PPA,SCA; Habitat: T; Effect Codes: GRO; Code: 

LITE EVAL CODED (ACAC,HCL,PPA,SCA).

Endpoints were not reported in units that were useful to the risk assessment.

Piola, R. F., Dunmore, R. A., and Forrest, B. M. (2010). Assessing the Efficacy of SprayDelivered 'Eco-Friendly' Chemicals for the Control and Eradication of Marine Fouling 

Pests. Biofouling 26: 187-203.

EcoReference No.: 151917

Chemical of Concern: ACAC,NaHCT; Habitat: A; Effect Codes: MOR,POP; Code: 

LITE EVAL CODED (ACAC), NO EFED CHEM (NaHCT).

Evaluated as “qualitative” and used in the risk assessment.

Rao, D. N. and Mikkelsen, D. S. (1977). Effect of Acetic, Propionic, and Butyric Acids on 

Young Rice Seedlings' Growth. Agron. J. 69: 923-928.

EcoReference No.: 42791

Chemical of Concern: ACAC,PPA; Habitat: T; Effect Codes: GRO; Code: LITE 

EVAL CODED (ACAC,PPA).

Endpoints were not reported in units that were useful to the risk assessment.

Rotstein, J. B. and Slaga, T. J. (1988). Acetic Acid, a Potent Agent of Tumor Progression in the 

Multistage Mouse Skin Model for Chemical Carcinogenesis. Cancer Lett. 42: 87-90.

EcoReference No.: 103294

Chemical of Concern: ACAC; Habitat: T; Effect Codes: CEL,MOR,PHY; Code: LITE 

EVAL CODED (ACAC).

Endpoint was not reported in units useful to the risk assessment.

Sashikala, R., Krishna Mohan, P., and Indira, K. (1985). Protein Degradation and 

Transamination Patterns in a Fresh Water Fish Under Ambient Ammonia Stress. 

Environ. Ecol. 3: 496-499.

EcoReference No.: 113390

Chemical of Concern: NHAC; Habitat: A; Effect Codes: BCM,MOR; Code: LITE 

EVAL CODED (NHAC).

Duration of the experiment was not 96 hours.
38

Sharma, S., Chanemougasoundharam, A., Sarkar, D., and Pandey, S. K. (2004). Carboxylic 

Acids Affect Induction, Development and Quality of Potato (Solanum tuberosum L.) 

Microtubers Grown In Vitro from Single-Node Explants. Plant Growth Regul. 44: 219-

229.

EcoReference No.: 101661

Chemical of Concern: ACAC,FMA,PPA; Habitat: T; Effect Codes: BCM,GRO,POP; 

Code: LITE EVAL CODED (ACAC,PPA), NO EFED CHEM (FMA).

Endpoints were not reported in units that were useful to the risk assessment.

Stopar, M. (2008). Vegetable Oil Emulsions, NaCl, CH3COOH and CaSx as Organically 

Acceptable Apple Blossom Thinning Compounds . Eur. J. Hortic. Sci. 73: 55-61.

EcoReference No.: 118202

Chemical of Concern: ACAC,CaPS,Halides,NaCl,SOYBN; Habitat: T; Effect Codes: 

BCM,GRO,PHY,REP; Code : LITE EVAL CODED 

(ACAC,CaPS,Halides,NaCl,SOYBN).

Evaluated as “qualitative” and used in the risk assessment.

Taylor, P. W. and Glenn, R. A. (2008). Toxicity of Five Therapeutic Compounds on Juvenile 

Salmonids. N. Am. J. Aquacult. 70: 175-183.

EcoReference No.: 107284

Chemical of Concern: ACAC,CuS,FML,HOX,KPM; Habitat: A; Effect Codes: MOR; 

Code: LITE EVAL CODED (ACAC,CuS,HOX), NO EFED CHEM (FML,KPM).

Endpoints were not useful and/or endpoints were not the lowest values.

Terhaar, C. J., Ewell, W. S., Dziuba, S. P., and Fassett, D. W. (1972). Toxicity of Photographic 

Processing Chemicals to Fish. Photogr. Sci. Eng. 16: 370-377.

EcoReference No.: 14566

Chemical of Concern: 

ACAC,Ag,Al,AlKS,BRA,CIT,FML,FeCl,FeCl3,K2Cr2O7,NACE,NH,NHTC,NHTS,Na

3P; Habitat: A; Effect Codes: MOR; Code: LITE EVAL CODED 

(ACAC,BRA,CIT,NACE), NO EFED CHEM 

(Al,AlKS,FML,FeCl,FeCl3,K2Cr2O7,NH,NHTC,NHTS,Na3P), OK (Ag).

Endpoints were not useful to the risk assessment.

Thompson, C. R., Kats, G., and Lennox, R. W. (1979). Phytotoxicity of Air Pollutants Formed 

by High Explosive Production. Environ. Sci. Technol. 13: 1263-1268.

EcoReference No.: 54817

Chemical of Concern: ACAC,SO2; Habitat: T; Effect Codes: PHY; Code: LITE 

EVAL CODED (ACAC,SO2).\
39

Endpoints were not reported in units that were useful to the risk assessment.

Treverrow, N. L. (1991). Rice Bloodworm, Toxicity of Fatty Acids, 1981. Insectic. Acaric. 

Tests 16: 297-(15L).

EcoReference No.: 103759

Chemical of Concern: ACAC,CAC,CRA,FMA,PPA; Habitat: A; Effect Codes: MOR; 

Code: LITE EVAL CODED (ACAC,CAC,CRA,PPA), NO EFED CHEM (FMA).

Endpoint was not reported in units that were useful to the risk assessment.

Union Carbide Corp. (1978). The Acute Toxicity of Sodium Acetate to the Bluegill Sunfish 

Lepomis macrochirus Rafinesque with Attachments and Cover Letter Dated 033178. 

EPA/OTS Doc. #88-7800120 48 p. (NTIS/OTS0200477).

EcoReference No.: 152077

Chemical of Concern: NACE; Habitat: A; Effect Codes: BEH,MOR; Code: LITE 

EVAL CODED (NACE).

Non-definitive endpoint and study duration was not in accord with OPP Guidelines.

Utz, L. R. P. and Bohrer, M. B. C. (2001). Acute and Chronic Toxicity of Potassium Chloride 

(KCl) and Potassium Acetate (KC2H3O2) to Daphnia similis and Ceriodaphnia dubia 

(Crustacea; Cladocera). Bull. Environ. Contam. Toxicol. 66: 379-385.

EcoReference No.: 62282

Chemical of Concern: KACE,KCl; Habitat: A; Effect Codes: GRO,MOR,REP; Code: 

LITE EVAL CODED (KACE), NO EFED CHEM (KCl).

Not the most sensitive endpoints and study duration was not always in accord with OPP 

Guidelines.

Van Engelsdorp, D., Underwood, R. M., and Cox-Foster, D. L. (2008). Short-Term Fumigation 

of Honey Bee (Hymenoptera: Apidae) Colonies with Formic and Acetic Acids for the 

Control of Varroa destructor (Acari: Varroidae). J. Econ. Entomol. 101: 256-264.

EcoReference No.: 151934

Chemical of Concern: ACAC,FMA; Habitat: T; Effect Codes: MOR,POP; Code: 

LITE EVAL CODED (ACAC), NO EFED CHEM (FMA).

Evaluated as “qualitative” and used in the risk assessment.

Wallace, J. M. and Whitehand, L. C. (1980). Adverse Synergistic Effects Between Acetic, 

Propionic, Butyric and Valeric Acids on the Growth of Wheat Seedling Roots. Soil Biol. 

Biochem. 12: 445-446.

EcoReference No.: 101600

Chemical of Concern: ACAC,PPA; Habitat: T; Effect Codes: GRO; Code: LITE 
40

EVAL CODED (ACAC,PPA).

Mixture and units were not useful to the risk assessment.

Weissinger, W. R. and Beuchat, L. R. (2000). Comparison of Aqueous Chemical Treatments to 

Eliminate Salmonella on Alfalfa Seeds. J. Food Prot. 63: 1475-1482.

EcoReference No.: 101729

Chemical of Concern: ACAC,CIT,CaOCl,EDTA,EPXA,HOX,LLA,NaHCT; Habitat: T; 

Effect Codes: REP; Code: LITE EVAL CODED (ACAC,CIT,EPXA,HOX,LLA), NO 

EFED CHEM (CaOCl,EDTA,NaHCT).

Duration of the test was only three days.

Wu, Q. T., Deng, J. C., Long, X. X., Morel, J. L., and Schwartz, C. (2006). Selection of 

Appropriate Organic Additives for Enhancing Zn and Cd Phytoextraction by 

Hyperaccumulators. J. Environ. Sci. 18: 1113-1118.

EcoReference No.: 114088

Chemical of Concern: ACAC,CIT,EDTA,OXAC; Habitat: T; Effect Codes: 

BCM,POP,REP; Code: LITE EVAL CODED (ACAC,CIT,OXAC), NO EFED CHEM 

(EDTA).

Endpoints were not reported in units useful for the risk assessment.

Zurowski, D., Dobrek, L., Bugajski, A., and Thor, P. J. (2008). The Role of Sensory C-Fibers in 

Response of Vagal Afferent Stimulation by Gastric Distension in Rats with Experimental 

Chronic Gastric Ulcer. J. Physiol. Pharmacol. 59: 179-189.

EcoReference No.: 151795

Chemical of Concern: ACAC,CPS; Habitat: T; Effect Codes: PHY; Code: LITE 

EVAL CODED (ACAC,CPS).

Endpoint was not reported in units useful to the risk assessment.
41

Sodium Diacetate

CH3COONa· CH3COOH

Acetic Acid

CH3COOH

Sodium Acetate

CH3COONa

CH3COOˉ 2CO2 2 H2O

 Na+

2CO2 CH4

or 

C2H6

Appendix A. Degradation Pathways of Sodium Diacetate (MRID 2058971)

Dissociation

+ O2

2CH3COOˉ

Aerobic Anarobic