~~~~ 

ia~ ~ \ ~~! 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

~ ~ ~~~ 

MEMORANDUM 

SUBJECT: 

TO: 

FROM: 

THRU: 

Executive summary 

September 7, 2011 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

Amines, ClO-16 alkyldimethyl, N-oxides. Product Chemistry, 

Environmental Fate, and Ecological Effects Scoping Document for 

Registration Review. 

PC Code: 000439 DP Barcode: 392700 

Decision No.: 452862 Registration No.: See Table 1 

Petition No(s).: NA Regulatory Action: Ecological 

Environmental Scoping Document 

for Registration Review 

Risk Assessment Type: Single Case No.: 5003 

chemical 

TXRNo.:NA CAS No.: 70592-80-2 

MRlD Nos. : See Table 2 and Pg.no.5 40 CFR: None 

Seiichi Murasaki, Chemical Review Manager 

Regulatory Management Branch II 

Antimicrobials Division (75 1 OP) 

Risk 

Srinivas 

Assessment 

Gowda, Microbiolo

and Science 

gis

Support 

t S -0\ 

Branch 

~ " 

(RASSB) 

\C0l ~~ 

Antimicrobials Division (75 1 OP) 

Nader Elkassabany, Branch Chief ~~ . 

Siroos Mostaghimi, Peer Re iewer~ ~ 

Risk Assessment and Science Support Branch (RAS'SBf 

Antimicrobials Division (75 1 OP) 

ADAO is an end use product registered for residential use as an antibacterial dish 

detergent. All product chemistry data requirements have been satisfied for ADAO. 

Agency's in-house database does not have any acceptable environmental fate and 

transport data on ADAO which are required to conduct an environmental fate assessment 

for residential antibacterial dishwashing detergents that may potentially pass through 

waste water treatment plants (WWTPs) and may be discharged into terrestrial and aquatic 

environments. ADAO is on the 2007 Organization for Economic Co-operation and 

Development (OECD) list of high production volume chemicals (The 2007 OECD List of 

Page 1 of 16 
Page 2 of 16

High Production Volume Chemicals, Series on Testing and Assessment, Number 112, 23 

October 2009) and is among those chemicals for which a Screening Information Data Set 

(SIDS) has been performed. An examination of the chemical structure and a review of 

information in the SIDS Initial Assessment Report for Amine Oxides (SIDS Initial 

Assessment Report for SIAM 22, Paris, France, 18-21 April 2006) indicates that a high 

percentage of amine oxides are removed by conventional sewage treatment systems. 

According to the SIDS Initial Assessment Report, ―Removal of amine oxides in

biological wastewater treatment has been studied in laboratory simulation studies 

(>99.8% removal, OECD 303A study) as well as through monitoring activities in 

different geographies; the main removal mechanism can be attributed to mineralization 

and an average removal number of 98% can be assumed as applicable for secondary 

activated sludge treatment.‖ The Environmental Fate and Pathways section of the SIDS 

dossier on this particular class of amine oxides (CAS No. 70592-80-2) summarizes 

monitoring studies and biodegradation studies that appear to substantiate this claim.

To be able to give merit to this claim, the Agency would need to review and 

evaluate the primary references cited in this SIDS dossier. Without reviewing and 

evaluating these primary references and reaching the same conclusions as those presented 

in the SIDS Initial Assessment Report, for this assessment the Agency anticipates 

needing fate data such as hydrolysis and photodegradation in water, modified activated 

sludge respiration inhibition, activated sludge sorption isotherm; ready biodegradability, 

porous pot test, or simulation tests to assess the biodegradability of chemicals discharged 

in wastewater, or simulation test – aerobic sewage treatment: A. Activated Sludge Units. 

ADAO is practically non-toxic to mammals on an acute oral basis; and moderately toxic 

to freshwater fish and invertebrate. For the ecological risk assessment, including an 

endangered species assessment for all uses, the Agency anticipates needing the acute 

avian oral toxicity data and algal toxicity data.

Introduction

Amines, C10-16-alkyldimethyl, N-oxides also chemically known as Alkyl (C10-16)

dimethylamine oxides (ADAO), are non-ionic, dipolar surfactants which are generally 

used in detergents at low levels in conjunction with other surfactants. ADAO are 

effective in the presence of greasy soil and are commercially sold as 26-31% aqueous 

solutions.

Nonionic surfactants do not ionize in aqueous solution, because their hydrophilic 

group is of a nondissociable type, such as alcohol, phenol, ether, ester, or amide. The 

dimethyl(C10-C16-alkyl)amine N-oxides (ADAO) are produced as a mixture comprised of 

dimethyldecylamine (CDAO, C10), dimethylundecylamine (UDAO, C11), 

dimethyldodecylamine (DDAO, C12) , dimethyltridecylamine (TDAO, C13), 

dimethyltetradecylamine (MDAO, C14), dimethylpentadecylamine (PDAO, C15), and 

dimethyhexadecylamine (HDAO, C16) N-oxides. Mixtures of (C12-C16) ADAO are referred to 

as coco—dimethylamine oxide, which is a clear corrosive liquid that is soluble in water and 

polar solvents. It decomposes before boiling at atmospheric pressure. The amine oxides are 

dipolar surfactants which can undergo several types of reactions associated with the amine 

oxide moiety.
Page 3 of 16

ADAO was initially registered as a pesticide in the United States in 1999 for use 

as an antibacterial dish detergent. Currently there is only one end-use product registered 

for residential use as an antibacterial dish detergent listed in Table 1. The product is not 

for use in dishwasher. It is intended for handwashing of dishes, dishware, cutlery, 

utensils, and cutting boards, and for general dishwashing use to kill 99.9% of bacteria 

such as Salmonella choleraesuis, Escherichia coli, Staphylococcus aureus, E. coli 0157, 

and Listeria monocytogenes on dishware (dishes/utensils). To kill bacteria on dishes the 

product is to be applied manually as a concentrate directly onto dishes, spread over the 

surface and allowed to stand 5 minutes before rinsing. A Reregistration Eligibility 

Decision (RED) has not been issued by EPA for Amines, C10-16-alkyldimethyl, N-oxides, 

because the initial registration date was after the November 1984, the mandated cutoff for 

initiation of the RED process.

Table 1. Registered Product of ADAO

Registration # Registration Name Company Name Formulation 

Type

% of Active

Ingredient

3573-62 Cleaning Magic II Proctor & Gamble Ready to use 

solution

5.2

EPA Reg. No. 3573-62

Cleaning Magic II

Active Ingredient:

Alkyl (C10-16) dimethyl amine oxide ..5.2%

For residential use only.

Contains no phosphate.

Not for use in dishwasher.

For general dishwashing, use as any dishwashing detergent.

Concentrated Dishwashing Detergent and Antibacterial Treatment.

Antibacterial action.

Kills 99.9% of bacteria on dishes such as Salmonella choleraesuis, Escherichia coli, 

Staphylococcus aureus, E. coli 0157, and Listeria monocytogenes.

Makes dishes/dishware/plastic dishware/plastic cutting boards/cutlery/utensils 99.9% 

bacteria free.

Kills 99.9% bacteria on dishes/dishware/plastic dishware/plastic cutting 

boards/cutlery/utensils that could contaminate clean dishes.

Kills 99.9% of common household bacteria, bacteria associated with food preparation

and common kitchen bacteria.

Helps fight bacteria on dishes/dishware/plastic dishware/plastic cutting 

boards/cutlery/utensils.

Help reduce the risk of cross-contamination from treated surfaces in kitchen.

May help prevent the transfer of bacteria from dishes to other kitchen surfaces.
Page 4 of 16

The Agency has conducted a review of the available product chemistry, 

environmental fate, and ecotoxicity data for ADAO. The findings are summarized below.

A. Product Chemistry Summary (Technical 32% aqueous solution of ADAO)

Common Name: Amine oxide, C10-16-alkyldimethyl; Amine oxide

(C10-C16)Alkyldimethylamine oxide

Chemical Names: Amines, C10-16-alkyldimethyl, N-oxide

Alkyl (C10-16) dimethyl amine oxide (ADAO)

Alkyl dimethyl amine oxide (ADAO)

IUPAC Name: N, N-dimethyltridecan-1-amine oxide

Trade and Other Names: AO-1280-LN (32% aqueous solution)

OPP Chemical Code: 000439

CAS Registry Number: 70592-80-2

Case: 5003

Chemical Family: Surfactant

Molecular Formula: C15H33NO; C10-16 H21-33N(CH3)2 O

Molecular weight: 235.7 [g/mol] (mean mixture value)

Molecular Structure:

Color: Light yellow

Physical State: Liquid

Odor: Weedy odor

Stability: Stable up to 100°F; other than excessive heat which 

leads to color degradation, no other conditions 

affect stability.

Oxidation/Reduction: Low capacity to act as an oxidizing agent. No 

reducing capacity. The solution will cause rusting of

non-stainless ferrous metals.
Page 5 of 16

Flammability-Flash Point: Over 300°F

Explodability: Amine oxide solution does not contain any 

explosive ingredient or fractional group therefore 

guideline is not applicable.

Storage Stability: Stable up to 100°F; other than excessive heat which 

leads to color degradation, no other conditions 

affect stability.

Miscibility: Amine oxide solution is not an emulsifiable liquid 

bearing directions for dilution with petroleum 

solvents, and therefore guideline is not applicable.

Corrosion Characteristics: No corrosive characteristics other than rusting nonstainless ferrous metals.

Dielectric breakdown voltage: Not applicable.

pH: 7.2

UV/Visible absorption: Not provided.

Viscosity: 30-50 cps at 25°C.

Melting point: Not applicable.

Boiling Point: 100°C at 1 atm.

Density: 1.0 at 25°C

Specific Gravity: 1.0 at 25°C

Dissociation Constant: Not applicable. Has no measurable dissociation 

constant.

Log Ko/w: 5.3 (estimated).

Solubility: Completely soluble in water at 70°F.

Vapor Pressure: 17.5 mm Hg at 68°F.

Enforcement Analytical

Method: Titration.

All product chemistry data requirements have been satisfied for the active 

ingredient ADAO (MRIDs 444349-01, 444349-02, 444349-03, & 444347-04).
Page 6 of 16

B. Environmental Fate Summary

The following five non-guideline environmental fate studies were submitted by 

the Proctor & Gamble Company. These studies were reviewed by the Agency and found 

insufficient/rejected because they were very old and/or not conducted according to the 

current EPA guidelines.

1. A Biodegradability Study of Dodecyl Dimethyl Amine Oxide (DDAO) (MRID 

44434914) .

2. Isolation, Identification and Quantitation of the Semi-continuous Activated 

Sludge Metabolite(s) of Dodecyldimethylamine Oxide (DDAO) (MRID 

44434915).

3. Biodegradation Study of E-5139.01 Continuous Activated Sludge Simulation Test 

(MRID 44475205).

4. Fate of (carbon 14)-Dimethyldodecylamine Oxide (DDAO) During Activated 

Sludge Treatment (CAS Test) (MRID 44475206).

5. Hydrolysis of TSIN GTS02902 as a Function of pH (MRID 46008802).

No risk assessment was performed for ADAO at the time of the registration. The 

Agency has not received any acceptable guideline environmental fate studies on ADAO, 

which are required to conduct an environmental fate assessment for residential 

antibacterial dishwashing detergents (including ADAO) that may potentially pass through 

waste water treatment plants (WWTPs) and may be discharged into terrestrial and aquatic 

environments. ADAO is on the 2007 Organization for Economic Co-operation and 

Development (OECD) list of high production volume chemicals (The 2007 OECD List of 

High Production Volume Chemicals, Series on Testing and Assessment, Number 112, 23 

October 2009) and is among those chemicals for which a Screening Information Data Set 

(SIDS) has been performed. An examination of the chemical structure and a review of 

information in the SIDS Initial Assessment Report for Amine Oxides (SIDS Initial 

Assessment Report for SIAM 22, Paris, France, 18-21 April 2006) indicates that a high 

percentage of amine oxides are removed by conventional sewage treatment systems. 

According to the SIDS Initial Assessment Report, ―Removal of amine oxides in 

biological wastewater treatment has been studied in laboratory simulation studies 

(>99.8% removal, OECD 303A study) as well as through monitoring activities in 

different geographies; the main removal mechanism can be attributed to mineralization 

and an average removal number of 98% can be assumed as applicable for secondary 

activated sludge treatment.‖ The Environmental Fate and Pathways section of the SIDS 

dossier on this particular class of amine oxides (CAS No. 70592-80-2) summarizes 

monitoring studies and biodegradation studies that appear to substantiate this claim.

To be able to give merit to this claim, the Agency would need to review and 

evaluate the primary references cited in this SIDS dossier. Without reviewing and 

evaluating these primary references and reaching the same conclusions as those presented 

in the SIDS Initial Assessment Report, for this environmental fate assessment the Agency 

anticipates needing those data outlined on page 10 of this document.
Page 7 of 16

Water Quality

ADAO is not identified as a cause of impairment for any water bodies listed as 

impaired under section 303(d) of the Clean Water Act, based on information provided at 

the Agency‘s National Pesticides Cause of Impairment of Waters website (searched April 

7, 2011)1. In addition, no Total Maximum Daily Loads (TMDL) have been developed 

for ADAO, based on information provided at the Agency‘s National Pesticide TMDL 

web site (searched April 7, 2011)2. More information on impaired water bodies and 

TMDLs can be found at http://www.epa.gov/owow/tmdl/. The Agency invites 

submission of water quality data for this pesticide. To the extent possible, data should 

conform to the quality standards in Appendix A of the OPP Standard Operating 

Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s 

Registration Review Risk Assessment and Management Process (see: 

http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf ), in order to 

ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

C. Ecological Effects Summary

No ecological risk assessment was performed for ADAO at the time of the 

registration. Available ecotoxicity guideline studies and the results are summarized in 

Table 2. The Agency's conclusions for the terrestrial and aquatic effects studies are as 

follows.

a. Toxicity to Terrestrial Animals

Birds, Acute and Subacute

No avian acute oral toxicity data have been submitted. For the ecological 

risk assessment, including an endangered species assessment for all uses, 

the Agency anticipates needing the avian acute oral toxicity data outlined 

on page 8 of this document.

Toxicity to Mammals

Acute toxicity data for ADAO show practically non-toxicity for oral dose 

(oral LD50 = 4800 mg/kg).

There is currently no 2-generation rat reproduction study but in the human 

health scoping document it has been identified as a data gap.

b. Toxicity to Aquatic Animals

 

1

. http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

2

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_p

ollutant_group_name=PESTICIDES
Page 8 of 16

Freshwater Fish and Invertebrates

ADAO is moderately toxic to freshwater fish and aquatic invertebrates.

The submitted ecological effects studies were reviewed as supplemental 

and adequate for purposes of labeling: thus these studies do not need to be 

repeated. The data showed that ADAO is moderately toxic to bluegill 

sunfish, freshwater fish, with the LC50 values ranging from 3.1 - 6 4 ppm 

and to Daphnia magna, a freshwater aquatic invertebrate with LC50 value 

as 1.01 ppm.

d. Toxicity to Aquatic Plants

Freshwater Algae

No algal toxicity data have been submitted. For the ecological risk 

assessment, including an endangered species assessment for all uses, the 

Agency anticipates needing the algal toxicity data outlined on page 10 of 

this document.

Table 2. Ecotoxicity Data Summary for ADAO

MRID GUIDELINECOMMON

NAME

TAXONOMIC

NAME

TEST

TYPE

AI STUDY

TIME

DOSE

TYPE

TOXI

CITY

TOX

LEVEL

NOEL STUDY 

STATUS

TOX 

CATEGORY

Freshwater Fish Acute Toxicity

44434911 850.1075

(72-1)

Bluegill 

sunfish

Lepomis 

macrochirus

S N.R. 96 hr LC50 6.4 PPM N.R. SupplementalModerately 

toxic

44434912 850.1075

(72-1a)

Bluegill 

sunfish

Lepomis 

macrochirus

S N.R. 96 hr LC50 3.13 PPM 1.20 SupplementalModerately 

toxic

Freshwater Invertebrate Acute Toxicity

44434913 850.1010

(72-2)

Water 

flea

Daphnia 

magna

F N.R. 96 hr EC50 1.01 PPM 0.70 SupplementalModerately 

toxic

Terrestrial Mammalian Acute Oral Toxicity

44475201 870.1100

81-1

Rat ----- ----- 27.72 ----- LD50

LD50

(Combined)

5400(M)

3900(F)

4800

mg/kg/bw ----- Acceptable Practically 

non- toxic 

(III)

Test Type—F: flow-through; S: static.

Tox Level—mg/kg/bw: milligrams per kilogram-body weight; ppm: parts per million (equivalent to milligrams per liter (mg/L) 

for aquatic exposures)

Categories of acute toxicity for aquatic organisms (U.S. EPA, 2004) based on EC50/LC50(mg/L): < 0. 1 very highly toxic; 0.1-1 

highly toxic; >1-10 moderately toxic; >10-100 slightly toxic; >100 practically nontoxic. 

Categories of acute toxicity to terrestrial animals, avian and mammalian (U.S. EPA, 2004). LD50 (mg/kg bw): < 10 very 

highly toxic; 10 - 50 highly toxic; 51 - 500 moderately toxic; 501-2000 slightly toxic; >2000 practically non-toxic.

Adverse Ecological Incidents

There are no reported incidents in the Agency's Ecological Incident Information 

System (EIIS) regarding ADAO. The absence of documented incidents does not 

necessarily mean that such incidents did not occur.
Page 9 of 16

Ecological Effects Risk Assessment

An ecological risk assessment was not conducted on the ADAO ̳s antibacterial 

dishwashing detergent use pattern described in this document. ADAO‘s uses that have 

potential for environmental exposure are down the drain antibacterial dishwashing 

detergent discharges. The Agency needs to conduct environmental fate and ecological 

risk assessments for antibacterial dishwashing detergents that potentially pass through 

waste water treatment plants (WWTPs) and may be discharged into terrestrial and aquatic 

environments. For this ecological risk assessment, including an endangered species 

assessment for all uses, the Agency anticipates needing the avian acute oral and algal 

toxicity data outlined on page 10 of this document.

The Agency has not conducted a risk assessment for ADAO that supports a 

complete endangered species effects determination. The ecological risk assessment 

planned during registration review will allow the Agency to determine whether ADAO‘s 

use has ―no effect‖ or ―may affect‖ federally listed threatened or endangered species 

(listed species) or their designated critical habitats. When an assessment concludes that a 

pesticide‘s use ―may affect‖ a listed species or its designated critical habitat, the Agency 

will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries 

Services (the Services), as appropriate.

Environmental Fate and Ecotoxicity Data Gaps and Anticipated Work

Environmental fate and ecological risk assessments have not been conducted for 

ADAO. The Agency needs to conduct environmental fate and ecological risk 

assessments for residential antibacterial dishwashing detergents that potentially pass 

through waste water treatment plants (WWTPs) and may be discharged into terrestrial 

and aquatic environments. ADAO is on the 2007 Organization for Economic Cooperation and Development (OECD) list of high production volume chemicals (The 2007 

OECD List of High Production Volume Chemicals, Series on Testing and Assessment, 

Number 112, 23 October 2009) and is among those chemicals for which a Screening 

Information Data Set (SIDS) has been performed. An examination of the chemical 

structure and a review of information in the SIDS Initial Assessment Report for Amine 

Oxides (SIDS Initial Assessment Report for SIAM 22, Paris, France, 18-21 April 2006) 

indicates that a high percentage of amine oxides are removed by conventional sewage 

treatment systems. According to the SIDS Initial Assessment Report, ―Removal of amine 

oxides in biological wastewater treatment has been studied in laboratory simulation 

studies (>99.8% removal, OECD 303A study) as well as through monitoring activities in 

different geographies; the main removal mechanism can be attributed to mineralization 

and an average removal number of 98% can be assumed as applicable for secondary 

activated sludge treatment.‖ The Environmental Fate and Pathways section of the SIDS 

dossier on this particular class of amine oxides (CAS No. 70592-80-2) summarizes 

monitoring studies and biodegradation studies that appear to substantiate this claim.

To be able to give merit to this claim, the Agency would need to review and 

evaluate the primary references cited in this SIDS dossier. Without reviewing and 
Page 10 of 16

evaluating these primary references and reaching the same conclusions as those presented 

in the SIDS Initial Assessment Report, the Agency anticipates needing the proposed 

environmental fate and ecotoxicity data for ADAO and/or any of its major degradation 

products that are of potential concern for all registered uses of ADAO. The following 

environmental fate and ecotoxicity data are needed to conduct an environmental fate and 

ecological risk assessment:

The Agency anticipates needing the following data to conduct a complete 

environmental fate assessment for residential antibacterial dishwashing 

detergent use:

o (GLN 835.2120) Hydrolysis;

o (GLN 835.2240) Photodegradation in water;

o (GLN 850.6800) Modified Activated Sludge Respiration Inhibition;

o (GLN 835.1110) Activated Sludge Sorption Isotherm;

o (GLN 835.3110) Ready biodegradability, (GLN 835.3220) Porous Pot 

Test, or (GLN 835.3280) Simulation Tests to Assess the Biodegradability 

of Chemicals Discharged to Wastewater, or (GLN 835.3240) Simulation 

Test – Aerobic Sewage Treatment: A. Activated Sludge Units3.

The Agency anticipates needing the following ecotoxicity data in order to 

conduct a complete ecological risk assessment, including an endangered 

species assessment:

o (GLN 850.2100) Acute avian oral toxicity; and

o (GLN 850.5400) Algal toxicity (Tier II) using freshwater green alga, 

Selenastrum capricornutum.

 

3 The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these 

biodegradation tests are required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either the 

Biodegradation in Activated Sludge Study or the Porous Pot Test is required. If the ASRI test EC50 is 

greater than 20 mg/L, then the applicant must choose either: (i) Ready Biodegradability or (ii) 

Biodegradation in Activated Sludge or the Porous Pot Test. If the antimicrobial passes the ready 

biodegradability study, then no further testing is required. If, however, the antimicrobial fails the ready 

biodegradability study, then the Biodegradation in Activated Sludge or the Porous Pot study is required.
Page 11 of 16

Appendix A. Environmental Fate Guideline Study Justifications

Guideline Number: 835.2120

Study Title: Hydrolysis

Practical Utility of the Data

1) What is the value of the study?

Data characterizing the rate of hydrolytic degradation of ADAO and/or the formation and decline of 

degradates is important in determining the persistence and concentrations of ADAO and potential 

degradates over time in various aquatic environments. For outdoor uses, ADAO can reach surface water 

through direct contact or discharge to WWTPs. ADAO may also reach surface water or groundwater 

through run-off or leaching processes. The Agency will evaluate the potential risks of concern.

2) How would the data be used?

The data would establish the significance of chemical hydrolysis as a route for degradation and identify, if 

possible, the hydrolytic transformation products formed that may adversely affect non-target organisms and 

may contaminate water and food source of aquatic organisms. The data would also help establish the 

hydrolytic half-life of ADAO and possibly degradates, and assist in developing a degradation pathway.

3) How could the data affect the risk assessment?

The results of hydrolysis data would indicate if ADAO is persistent or if it degrades into other products that 

may adversely affect nontarget organisms and may contaminate their food and water and possibly soil.

4) What is triggering the need for this data?

Hydrolysis data is needed to conduct the fate assessment to support antibacterial dishwashing detergent

uses for ADAO.

Guideline Number: 835.2240

Study Title: Photodegradation in water

Practical Utility of the Data

1) What is the value of the study?

Biocides introduced into aqueous systems in the environment can undergo photolytic transformation by 

sunlight. Results from the photolysis study will indicate the stability and persistence of ADAO and 

potential degradates in an aquatic environment when exposed to sunlight. The Agency will evaluate the 

potential risks of concern.

2) How would the data be used?

The data would establish the significance of chemical photolysis as a route for degradation and identify, if 

possible, the photolytic degradation products formed that may adversely affect non-target organisms and 

may contaminate water and food source of aquatic organisms. The data would also help establish the 

photolytic half-life of ADAO and possibly degradates, and assist in developing a degradation pathway.

3) How could the data affect the risk assessment?

The results of photolysis data would indicate if ADAO is persistent or if it degrades into degradation 

products that may adversely affect nontarget organisms and may contaminate their food. The results of the 

photolysis data would expand the understanding of the results of the hydrolysis data since environmental 

aquatic conditions usually involve exposure to sunlight.

4) What is triggering the need for this data?

Aqueous photodegradation data is needed to conduct the fate assessment to support antibacterial 

dishwashing detergent uses for ADAO.
Page 12 of 16

Guideline Number: 835.1110

Study Title: Activated Sludge Sorption Isotherm

Rationale for Requiring the Data

Data from this study are needed to determine the sorption potential of activated sludge for the removal 

of specific chemical compounds in biological wastewater treatment plants (WWTPs). If the chemical is 

not sorbed or biodegraded, then it would pass through a biological treatment system unaffected, 

potentially contaminating surface and drinking waters where it may then have the potential to adversely 

affect nontarget organisms. EPA needs activated sludge sorption study data to assess the distribution of 

the antimicrobial chemical among the solid, aqueous, and vapor phases of WWTPs. Specifically, this 

study identifies those chemicals which sorb to sludge biomass.

Practical Utility of the Data

1. How will the data be used?

The data will be used to assess removal of the antimicrobial as a result of sorption to activated sludge. 

Percent removal via sorption to activated sludge and percent removal via biodegradation are used to 

determine overall removal of the antimicrobial during wastewater treatment. Overall removal during 

wastewater treatment is a key input used to determine concentrations of the antimicrobial in surface water 

immediately downstream of wastewater treatment plants. The concentrations of antimicrobial pesticide 

immediately downstream of wastewater treatment plants are used to assess exposure and risk to non-target 

endangered and non-endangered species. Exposure data are integral parts of the risk equation for 

determining the impact of pesticides to beneficial nontarget organisms through direct exposure from their 

food sources and habitat.

In addition, the data will be used to determine whether or not additional studies and/or label restrictions are 

needed. If the data indicate that the chemical does not sorb to sludge and instead partitions more readily to 

water and that the chemical does not biodegrade to an appreciable extent then the chemical has the potential 

to pass through the WWTP and therefore could be discharged in to the aquatic environment. This 

determination could trigger further data requirements to assess the chemical‘s impact upon release. If the 

data indicates relatively high potential to sorb to sludge, a screening assessment of potential exposure to 

ecological organimsm as a result of biosolids use and disposal would performed.

2. How could the data impact the Agency’s future decision-making?

If the data show that removal of the chemical during wastewater treatment is negligible, then the risk 

assessments for this chemical would reflect the magnitude of potential risk derived from this chemical‘s 

negligible removal. The risk assessment may result in the Agency requiring label restrictions that would be 

necessary for the products to meet the ―no unreasonable adverse effects‖ requirements of FIFRA (e.g., 

changes to the directions for disposal).

In addition, EPA is required by section 7(a)(2) of the ESA to ensure that any action it authorizes or takes 

―...is not likely to jeopardize the continued existence of any endangered or threatened species or result in 

the destruction or adverse modification of critical habitat‖ and to use the best scientific data available‖ in 

carrying out this obligation. The data EPA intends to call in are necessary to inform the determination 

required by the ESA as to whether continued registration of a pesticide is not likely to jeopardize the 

species or its critical habitat. Absent this data EPA may not be able to conclude that this pesticide will not 

harm endangered species and may therefore need to consider other limitations on the use of the pesticide in 

order to fulfill the Agency‘s statutory obligations under the ESA. The lack of these data will limit the 

flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in 

use restrictions which are unnecessarily severe. 
Page 13 of 16

Guideline Number: 850.6800; OECD 209

Study Title: Modified Activated Sludge, Respiration Inhibition Test for Sparingly Soluble 

Chemicals; Activated Sludge Respiration Inhibition Test

Rationale for Requiring the Data

An activated sludge, respiration inhibition test (ASRI) is needed to identify whether this pesticide could 

harm activated sludge microorganisms found in biological wastewater treatment systems. The Agency 

will use these data to determine the potential impact of this chemical on waste water treatment plants 

(WWTPs) as a result of respiration inhibition of activated sludge microorganisms. This test is also 

necessary to enable EPA to establish correct concentrations for use in the biodegradability test, if that 

test is determined to be adequate for assessing biodegradation potential. Furthermore, the results of the 

Activated Sludge Respiration Inhibition Test (ASRI) determine which biodegradation test is required. If 

the ASRI test EC50 is less than or equal to 20 mg/L, then either the Biodegradation in Activated Sludge 

Study or the Porous Pot Test is required. If the ASRI test EC50 is greater than 20 mg/L, then the applicant 

must choose either: (i) Ready Biodegradability or (ii) Biodegradation in Activated Sludge or the Porous Pot 

Test. If the antimicrobial passes the ready biodegradability study, then no further testing is required. If, 

however, the antimicrobial fails the ready biodegradability study, then the Biodegradation in Activated 

Sludge or the Porous Pot study is required.

Practical Utility of the Data

1. How will the data be used?

The data will be used to assess potential adverse effects to activated sludge microorganisms. In addition, 

the data will be used to determine whether or not label restrictions are needed. The study will identify the 

inhibitory effect of this chemical on the treatment plant‘s microorganisms‘ respiration at different 

concentrations of the test substance and will identify the EC50, the effective concentration of the test 

substance at which the respiration rate is 50% of that shown by the control under conditions in this 

guideline. The data will also determine suitable non-inhibitory concentrations to be used in 

biodegradability tests.

2. How could the data impact the Agency’s future decision-making?

If the data indicate a high degree of activated sludge respiration inhibition, a more rigorous test for 

biodegradation in wastewater treatment will be required than the ready biodegradability test. Also, if a 

high degree of respiration inhibition is demonstrated and biodegradation and/or sorption is indicated to be 

negligible, the Agency may require label restrictions or mitigation measures to insure that activated sludge 

microorganisms will not be adversely impacted.
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Guideline Numbers: 835.3110, 835.3220, 835.3280, or 835.3240

Study Titles: Ready Biodegradability, Porous Pot Test, Simulation Tests to Assess the 

Biodegradability of Chemicals Discharged to Wastewater (particularly Biodegradation in 

Activated Sludge), or Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units,

respectively

Rationale for Requiring the Data

For antimicrobial chemicals that go down-the-drain and reach a WWTP, as part of its screening-level 

environmental fate assessment, EPA will analyze the potential impact of the antimicrobial chemical on the 

microorganisms in the biological treatment processes of a WWTP. Biodegradation is an important 

environmental pathway in which the antimicrobial is broken down by bacteria. This study results supply 

information on the rate of biological breakdown and the completeness of the degradation to carbon dioxide 

and water. A ready biodegradability study would allow the Agency to determine whether or not the 

chemical achieves  ̳ ̳pass levels‘‘ for ready biodegradability (e.g., 70% removal of dissolved organic 

carbon). The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these 

three biodegradation tests are required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either 

the Biodegradation in Activated Sludge Study or Simulation Test – Aerobic Sewage Treatment: A. 

Activated Sludge Units or the Porous Pot Test is required. If the ASRI test EC50 is greater than 20 mg/L, 

then the applicant must choose either: (i) Ready Biodegradability or (ii) Biodegradation in Activated 

Sludge or Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or the Porous Pot Test. 

If the antimicrobial passes the ready biodegradability study, then no further testing is required. If, however, 

the antimicrobial fails the ready biodegradability study, then the Biodegradation in Activated Sludge or 

Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units, or the Porous Pot study is 

required.

Practical Utility of the Data

1. How will the data be used?

The data from a biodegradation study will be used to determine the percent removal of the antimicrobial as 

a result of biodegradation of the antimicrobial by activated sludge microorganisms. Percent removal via 

biodegradation is a key input used to determine concentrations of the antimicrobial in surface water 

immediately downstream of wastewater treatment plants. The concentrations of antimicrobial pesticide 

immediately downstream of wastewater treatment plants are used to assess exposure and risk to non-target 

endangered and non-endangered species. Exposure data are integral parts of the risk equation for 

determining the impact of pesticides to beneficial non-target organisms through direct exposure from their 

food sources and habitat.

In addition, the data will be used to determine whether or not additional studies and/or label restrictions 

are needed. If the chemical does not achieve a  ̳ ̳pass level‘‘ for ready biodegradability, then the Agency 

would determine that the chemical has the potential to pass through the WWTP and therefore may be 

discharged in to the aquatic environment potentially resulting in exposure to non-target species. This 

determination would trigger further data requirements to assess the chemical‘s impact on the aquatic 

environment upon release.

2. How could the data impact the Agency’s future decision-making?

If the chemical is found to be readily biodegraded, then activated sludge microorganisms would be 

identified as highly biodegradable (90% removal via biodegradation). This result would be used in 

conjunction with wastewater treatment plant influent volume and measurement endpoints for aquatic 

organisms to determine concentrations of antimicrobial pesticide downstream of wastewater treatment 

plants. If high inhibition of activated sludge microorganisms (i.e., EC50 less than or equal to 20 mg/L) is 

determined in an activated sludge respiration inhibition test, then higher-tiered wastewater treatment plant 

(WWTP) biodegradation studies and/or an activated sludge sorption isotherm study may be triggered. If 

results of higher-tier WWTP biodegradation tests indicate low or negligible removal by biodegradation, the 
Page 15 of 16

risk assessments for this chemical would reflect the magnitude of potential risk derived from the chemical‘s 

lack of biodegradability. The risk assessment may result in the Agency requiring label restrictions that 

would be necessary for the products to meet the ―no unreasonable adverse effects‖ requirements of FIFRA 

(e.g., changes to the directions for disposal).

In addition, EPA is required by section 7(a)(2) of the ESA to ensure that any action it authorizes or takes 

―...is not likely to jeopardize the continued existence of any endangered or threatened species or result in 

the destruction or adverse modification of critical habitat‖ and to use the best scientific data available‖ in 

carrying out this obligation. The data EPA intends to call in are necessary to inform the determination 

required by the ESA as to whether continued registration of a pesticide is not likely to jeopardize the 

species or its critical habitat. Absent this data EPA may not be able to conclude that this pesticide will not 

harm endangered species and may therefore need to consider other limitations on the use of the pesticide in 

order to fulfill the Agency‘s statutory obligations under the ESA. The lack of these data will limit the 

flexibility that the Agency and registrants have in coming into compliance with the ESA and could result in 

use restrictions which are unnecessarily severe.

Appendix B: Ecological Guideline Study Justifications

Guideline Number: 850.2100

Study Title: Acute avian oral toxicity

Practical Utility of the Data

1) What is the value of the study?

The Agency currently does not have any acceptable acute avian oral toxicity data for ADAO. This study 

would allow the Agency to categorize ADAO as toxic or non-toxic to birds. If the avian acute oral LD50

(TGAI testing) is less than or equal to 100 mg a.i./kg, additional higher tier bird test would be needed.

2) How would the data be used?

This study would be used to evaluate the toxicity of ADAO to non-target birds in terrestrial and aquatic 

ecosystems.

3) How could the data affect the risk assessment? 

Adverse effects to non-target birds in terrestrial and aquatic ecosystems may result in mitigation to protect 

species at risk.

4) What is triggering the need for this data?

Acute avian oral toxicity study is required to establish the toxicity of a pesticide to birds.
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Guideline Number: 850.5400

Study Title: Algal toxicity (Tier II) using freshwater green alga, Selenastrum capricornutum

Practical Utility of the Data

1) What is the value of the study?

As part of an initial risk assessment, one indicator plant species is tested for phytotoxicity. This study 

would allow the Agency to categorize ADAO as toxic or non-toxic to plants. If toxic, additional higher tier 

plant tests would be needed. An endangered species assessment for endangered or threatened plants is not 

possible without this study.

2) How would the data be used?

This study would be used to evaluate the toxicity of ADAO to non-target plants in terrestrial and aquatic 

ecosystems.

3) How could the data affect the risk assessment?

Adverse effects to non-target plants in terrestrial and aquatic ecosystems may result in mitigation to protect 

species at risk. Mitigation might include reduced label dosages, neutralization of effluents prior to 

discharge into water, restrictions on use in sensitive ecosystems or where endangered species are present, or 

other mitigation measures.

4) What is triggering the need for this data?

Increased concern from state regulators and the public to evaluate impacts on WWTP operations, 

endangered species, and persistence in the environment, since initial registration, have triggered the need 

for this study. Green algae are critical to ecosystem health and productivity.