Page 2 of 15 dietary basis ; and moderately toxic to freshwater fish and i nvertebrate. For the ecological risk assessment, including an endangered species assessment for all uses, t he A gency requires the acute avian oral toxicity data, acute freshwater invertebrates toxicity data, acute freshwater fish toxicity data, and algal t oxicity data

.

I ntroduction

The first product containing 1

- (2

- Hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil) hereafter called alkyl imidazoline

, was registered in the United States in 1970. Currently, one end use product is register ed for use as a microbiocide in

fuel oil storage tanks (See Table 1 below).

Alkyl imidazoline is a microbiocide/microbiostat used in fuel and oil storage tank bottom water. It is used to prevent the growth of slime

- forming bacteria and fungi which might i nterfere with the use and quality of oils and fuels in storage tanks. Formulation

include s one soluble concentrate liquid product, with 25% active ingredient. Product is loaded and applied through a closed delivery system that has a proportioning pump or siphon type feeder to meter the pesticide product directly from the product container into the fuel oil as it is pumped into storage tanks. Product is not intended for homeowner use

or for use in or around residences.

There are two active ingredients in t he Alkyl imidazolines Case 3010; however, one of these active ingredients, 2

- heptadecentyl

- 2

- imidazoline (PC Code: 046612; CAS

No.: 30968

- 43

- 5), does not have active registered products. This chemical is not being supported and is not addressed in this re gistration review. 1

- (2

- Hydroxyethyl)

- 2

- alkyl

- 2

- imidazoline (as in fatty acids of tall oil) is the only active ingredients in the case with active products. A Reregistration Eligibility Decision (RED) was issued by EPA for Alkyl imidazolines in 1995 1

.

T able 1. Registered Product of 1

- (2

- Hydroxyethyl)

- 2

- alkyl

- 2

- imidazoline (as in fatty acids of tall oil)

Registration

No. Registration

Name Company

Name Formulation Type % of Active Ingredient

68708

- 3 NALCO 2210

Fuel Oil Treatment Nalco Energy Services,

L. P. Ready

- to

- use Solution 25

EPA Reg. No. 68708

- 3

2210 Fuel Oil Treatment NALCO Energy Services, L.P.

Active Ingredient:

l

- (2

- hydroxyethyl)

- 2

- alkyl (C 18 ) *

- 2

- imidazoline... 25.0% *As in Tall Oil Fatty Acids.

2210 Fuel Oil Treatment Is Intended For Industri al Use Only.

1 http://www.epa.gov/oppsrrd1/REDs/3010red.pdfPage 3 of 15 For Use with Closed Delivery Systems Only

To inhibit sludge formation, to disperse existing sludge and to control filter

- plugging bacteria and fungi in fuel oil storage tanks and feed lines, use 40 to 80 ppm of 2210 Fuel

Oil Treatment based on fuel oil. Higher dosage may be required to completely inhibit some bacteria not considered to be factors in filter plugging.

Feed 2210 Fuel Oil Treatment by means of proportioning pump or siphon type feeder directly from drum or other container to the fuel oil as it is pumped into storage tanks.

The Agency has conducted a review of the available product chemistry, environmental fate, and ecotoxicity data for 1

- (2

- Hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil). The primary source of information for this assessment w as the 1995 Alkyl imidazolines RED. The findings are summarized below.

Product Chemistry Summary (Nalco PR

- 471/NALCO 2210

- 25 % AI)

Common Name: Nalco PR

- 471, A lkyl imidazoline

Chemical Name: 1

- (2

- hydroxyethyl)

- 2

- al kyl*

- 2

- imidazoline (*as in fatty acids of tall oil)

1H

- Imidazole

- 1

- ethanol, 4,5

- dihydro

- , 2

- nortall

- oil alkyl deriv atives

. 2

- Alkyl*

- 2

- imidazoline

- 1

- ethanol *(as in fatty acids of tall oil)

Trade and Other Names: Nalco 2210, Fuel

- prep 1000

OPP Chemical Co de: 046609 CAS Registry Number: 61791

- 39

- 7

Case: 30 10 Chemical Family: Fatty Acid Salt

Ave. Molecular Formula: C 22 H 40

- 44 N 2 O

Ave. Molecular W eight: 350.58

Molecular Structure:

R= Nortall Oil

Color: Clear to slightly hazy

- amber

Physical State: Liquid

Odor: Slight, “amine

- like” Hydrocarbon

Stability: Product is stable in presence of metal and metal ions at normal temperature and temperatures up toPage 4 of 15 200°C. Product darkens on long

- term exposure to sunlight. The imidazoline can react with wat er to
form the amide.

Oxidation/Reduction: N/A, the product contains neither oxidizing nor reducing agents.

Flammability

- Flash Point: Flash point: 151°F

Explodability: N/A, the product contains no explosive agents. Storage Stability: After one year of storage, the ring clouse was found

at 80.48%.

Miscibility: Soluble in kerosene, toluene, heptane @ 0.01, 0.1, 1.0, and 10 volume %. Insoluble in water at all

cited %.

Corrosion Characteristics: Not Provided

.

Dielectric breakdown voltage: N/A, the produ ct is not used around electrical equipment

.

pH: N/A, product hydrocarbon soluble, not soluble in

water. 20% in isopropyl alcohol = 11.2

UV/Visible absorption: Not provided.

Viscosity: 97 cps @ 60oF

Melting point: This material is a mixture and has no true melting point (i.e. each component of the mixture melts at a different temperature)

. Determination of this endpoint is not applicable

.

Boiling Point: This material contains long

- chain hydrocarbons that degrade at much lower temperatures than those a t which they would be expected to boil.

Determination of this endpoint is not applicable.

Density: 0.940 ± .005 g/ml at 25°C or 7.6 lbs/gal

Specific gravity: 0.91

- 0.93 @ 60°F

Dissociation Constant: Product is a mixture. No value can be obtained

.Page 5 of 15 Lo g K o/w or log P : Product is a mixture. No value can be obtained.

This material has surfactant properties and will accumulate at the interface between hydrophobic and hydrophilic phases rather than equilibrating between the two phases. It will remain in t he organic phase (fuel/oil) in any mixture with water. Determination of this endpoint is not applicable.

Its affinity to the organic (fuel) phase of the

mixture.

Solubility: Insoluble in water (8 mg/L in water)

.

This material is a mixture and has no single value for water solubility

. Determination of t his endpoint is not applicable.

Soluble in kerosene, toluene, heptane @ 0.01, 0.1, 1.0, and 10 volume percent . Insoluble in water at

all cited percent

.

Vapor Pressure: <0.1 mm Hg at 25 ° C

.

This mate rial is a large complex molecule with long

- chain hydrocarbons that are non

- volatile. Determination of this endpoint is not applicable.

Enf orcement Analytical

Method: Not provided.

All product chemistry data requirements have been satisfied for the activ e ingredient 1

- (2

- hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil). (Source: MRIDs 42434701, 43126801, 42434702, 42434703, 43379001

, 43373101 & 44402001).

Environmental Fate Summary

No risk assessment was performed for alkyl imidazoli ne at the time of the registration

. The Agency has not received any guideline environmental fate studies on alkyl imidazoline which are required to conduct an environmental fate assessment for material preservatives (including alkyl imidazoline) used in fu el oil storage tanks. For this assessment the Agency anticipates needing those data outlined on page 9 of this

document

.Page 6 of 15 Water Quality

1

- (2

- hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil) 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) 2 . In addition, no Total Maximum Daily Loa ds (TMDL) have been developed for 1

- (2

- hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil), based on information provided at the Agency’s National Pesticide TMDL web site (searched April 7, 2011) 3

http://www.epa.gov/owow/tmdl/ . More information on impaired water bodi es and TMDLs can be found at

. The Agency invites submission of water qu ality data for this pesticide. To the extent possible, data should conform to the quality standards in Append ix 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.

Ecological Effects Summary

No ecological risk assessment was performed fo r alkyl i midazolines at the time of the registration. Available e cotoxicity guideline studies and the r esults 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

No a vian acute oral toxicity data have been submitted. For the ecological risk assessment, including an endangered species assessment for all uses,

t he Agency anticipates needing the a vian acute oral toxicity data outlined on page 9 of this document

.

Birds, Subacute

A lkyl imidazoline is practically non toxic to avian species on subacute dietary basis.

Mammals , Acute

Alkyl imidazoline has slight oral toxicity.

2

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

3
http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pol lutant_detail?p_pollutant_group_id=885&p_p ollutant_group_name=PESTICIDESPage 7 of 15 There is currently no 2

- generation rat repro study and the human health scoping document identifie s this study as a data gap.

b . Toxicity to Aquatic Animals

Freshwater Fish and Invertebrates

Alkyl imidazoline is moderately toxic to freshwater fish, with the LC 50 values ranging from 1.07

- 1.17 and to Daphnia magna, a freshw a ter aquatic invertebrate with E C 50 value as 1.7 ppm. However, these studies were found invalid and must be repeated.

c . Toxicity to Aquatic Plants

Freshwater Algae

No algal toxicity data have been submitted. For the ecological risk assessment, includin g an endangered species assessment for all uses, t he Agency anticipates needing the algal toxicity data outlined on page 9 of

this document

.

Table 2. Ecotoxicity Data Summary for 1

- (2

- hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil)

GUIDE

LINE COMMON

NAME TAXONOMIC

NAME TEST

TYPE %

AI STUDY

TIME DOSE

TYPE TOXI

CITY TOX

LEVEL NOEL STUDY

STATUS TOX

CATEGORY MRID

Avian Subacute Dietary Toxicity

850.2200 (71

- 2a) Bobwhite quail Colinus virginianus D 100 8 D LC 50 >5000 PPM 3180 Acceptabl e Practically

nontoxic 44004901

Freshwater Fish Acute Toxicity

850.1075

(72

- 1) Rainbow

trout Oncorhynchus mykiss S 25

100 96 hr LC 50 1.07

2.7 ppm N.R

2.2. Invalid Moderately

toxic 43373102

44004902

850.1075

(72

- 1) Bluegill

sunfish Lepomis

macrochirus S 25 96 hr LC 50 1.17 ppm N.R. Invalid Moderately

toxic 43373102

Freshwater Invertebrate Acute Toxicity

850.1010

(72

- 2) Water

flea Daphnia

magna S Form

TEP 48 hr EC 50 1.7 ppm <1.3 Invalid Moderately

Toxic 43379002

Terrestrial Mammalian Acute Oral Toxic ity

81

- 1 Sprague

Dawley

Rats ------ ---- 85±3%

----- LD 50 (Males)

LD 50 (Females)

LD 50 (Combined) 1948

1880

1932 mg/kg

bw ----- Acceptable Slightly

toxic

III 42293001

Test Type

— D: dietary; S: static.

% AI

— Form: TEP: typical end

- use product

Tox Level

— p pm: parts per million (equivalent to milligrams per kilogram

- diet (mg/kg

- diet) for dietary exposure and milligrams per liter (mg/L) for aquatic exposures) Toxicity

— N.R.: not reported Categories of acute toxicity for aquatic organisms (U.S. EPA, 2004) based on EC 50 /LC 50 (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). LC 50 (ppm): < 50 very highly toxic; 50

- 500 highly toxic; 501

– 1000 moderately toxic; 1001

- 5000 slightly toxic; >5000 practically non

- toxic. LD50 (mg/kg bw): < 10 very highly toxic; 10

- 50 highly toxic; 51

- 500 moderately toxic; 501

- 2000 slightly toxic; >2000 practically no n

- toxic.Page 8 of 15 Adverse Ecological Incidents

There are no reported incidents in the Agency' s Ecological Incident Information System (EIIS) regarding 1

- (2

- hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil). The absence of documented incidents does not necessarily mean that such

incidents did not occur.

Ecological Effects Risk Assessment

Alkyl imidazoline, is used as a preservative and fungicide to inhibit slime

- forming bacteria and fungi growth in fuel oil storage tank bottom water. An ecolo gical risk

assessment was not conducted on the a lkyl imidazoline ’s use pattern described in this

document as a microbiocide in fuel oil . The Agency needs to conduct environmental fate and ecological risk assessments for alkyl imidazoline ’ s fuel oil treatm ent use pattern
listed in this document. For this ecological risk assessment, including an endangered species assessment for fuel oil treatment use , t he Agency anticipates needing the ecological effects data outlined on page 9 of this document to character ize alkyl imidazoline’s toxicity to birds, fish, and aquatic invertebrates.

The Agency has not conducted a risk assessment for alkyl imidazoline that supports a complete endangered species effects determination. The ecological risk assessment planned dur ing registration review will allow the Agency to determine

whether alkyl imidazoline 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.Page 9 of 15 Environmental Fate and Ecot oxicity Data Gaps and Anticipated Work

Environmental fate and ecological risk assessments have not been conducted for

1

- (2

- hydroxyethyl)

- 2

- alkyl*

- 2

- imidazoline (*as in fatty acids of tall oil) . The Agency needs to conduct environmental fate and ecologica l risk assessments for alkyl

imidazoline’ s (*as in fatty acids of tall oil) fuel oil treatment use pattern listed in this

document. Therefore, the Agency anticipates needing the proposed environmental fate and ecotoxicity data for alkyl imidazoline and/or any of its major degradation products that are of potential concern for all registered uses of alkyl imidazoline . 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 fuel oil treatment use s :

o (GLN 835.2120) Hydrolysis;

o (GLN 835. 2240) Photodegradation in water

o (GLN 850.6800) Modified Activated Sludge Respiration Inhibition;

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 4

.

**•** The Agency anticipates needing the following eco toxicity data in order to

cond uct a complete ecological risk assessment, including an endangered species assessment:

o (GLN 850. 2100 ) Acute Avian Oral Toxicity;

o (GLN 850. 1010 ) Acute Freshwater Invertebrates Toxicity;

o (GLN 850. 1075 ) Acute Freshwater Fish Toxicity; and

o (GLN 850.5400) alga l toxicity (Tier II) using freshwater green alga, Selenastrum capricornutum

.

4 The results of the Activated Sludge Respiration Inhibition Test (ASRI) determine which of these biodegradation tests are required. If the ASRI test EC 50 is less than or equal to 2 0 mg/L, then either the Biodegradation in Activated Sludge Study or the Porous Pot Test is required. If the ASRI test EC 50 is greater than 20 mg/L, then the applicant must choose either: (i) Ready Biodegradability or (ii) Biodegradation in Activated Sludg e 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 10 of 15 

### 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 alkyl imidazoline and/or the formation and decline of degradates is important in determining the persistence and concentrations of alkyl imidazoline and potential degradates over time in various a quatic environments. Alkyl imidazoline can reach surface water through direct contact or discharge to WWTPs. Alkyl imidazoline may also reach surface water or groundwater through run

- off or leaching processes. The Agency will evaluate the potential risk s 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 organism s and may contaminate water and food source of aquatic organisms. The data would also help establish the hydrolytic half

- life of alkyl imidazoline and possibly degradates, and assist in developing a degradation pathway.

3) How could the data affect the r isk assessment? The results of hydrolysis data would indicate if alkyl imidazoline 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 tri ggering the need for this data? Hydrolysis data is needed to conduct the fate assessment to support fuel oil treatment uses for alkyl

imidazoline

.

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 alkyl imidazoline and potential degr adates 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, i f 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 alkyl imidazoline and poss ibly 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 alkyl imidazoline is persistent or if it degrades into degradation products that may advers ely 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.Page 11 of 15 Guideline Number: 835.2240 Study Title: Photodegradation in water

4) What is triggering the need for this data? Aqueous photodegradation data is needed to conduct the fate assessment to support material preservative

uses for alkyl imidazoline

.

Guideline Number: 850.6800; OECD 209 Study Title: Modified Activated Sludge, Respir ation 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 mi croorganisms. 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 Sl udge Respiration Inhibition Test (ASRI) determine which biodegradation test is required. If

the ASRI test EC 50 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 EC 50 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 re quired. 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 microorgan isms’ respiration at different concentrations of the test substance and will identify the EC 50 , 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 rigo rous 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 r equire label restrictions or mitigation measures to insure that activated sludge microorganisms will not be adversely impacted.Page 12 of 15 Guideline Numbers: 835.3110, 835.3220, or 835.3280 Study Titles: Ready Biodegradability, Porous Pot Test, or Simulatio n Tests to Assess the Biodegradability of Chemicals Discharged to Wastewater (also referred to as Biodegradation in Activated Sludge), respectively Rationale for Requiring the Data For antimicrobial chemicals that go down

- the

- drain and reach a WWTP, as p art 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 whi ch the antimicrobial is broken down by bacteria. This study results suppl y 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 determi ne 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 a re required. If the ASRI test EC 50 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 EC 50 is greater than 20 mg/L, then the applicant must choose either: (i) Re ady 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 stu dy, 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 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 plan ts. 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

de termining 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 e xposure 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 foun d 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 endpoi nts 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 slud ge 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 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).Page 13 of 15 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 EP A 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 t his 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 th e 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: A cute avian oral toxi city 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 alkyl imidazoline

. This study would allow the Agency to categorize alkyl imidazoline as toxic or no n

- toxic to birds. If the

avian acute oral LD 50 (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 alkyl imidazoline 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 trigg ering the need for this data? Acute avian oral toxicity study is required to establish the toxicity of a pesticide to birds.

Guideline Number: 850.1075 Study Title: Acute Freshwater Fish Study (2 species)

Guideline Number: 850.1010 Study Title: Acute Toxicity Freshwater Invertebrates Study Practical Utility of the Data 1) What is the value of the study? Invertebrates serve as food for fish, birds, and crustaceans. The protection of non

- target invertebrates is essential to the food chain in any healt hy ecosystem. Sport fishing and commercial fishing have a high impact on the United States economy. The acute toxicity tests are designed to measure mortality during short term ( 48 hours for Daphnids and 96 hours for fish ) aquatic exposure to a range of c oncentrations of the pesticide in water.

2) How would the data be used? The data would allow the Agency to determine acute risk to freshwater fish and invertebrates from water column exposure to alkyl imidazoline. The effects data would be used to determ ine the likelihood thatPage 14 of 15 Guideline Number: 850.1075 Study Title: Acute Freshwater Fish Study (2 species)

Guideline Number: 850.1010 Study Title: Acute Toxicity Freshwater Invertebrates Study Practical Utility of the Data the acute risks can potentially impact aquatic communities, either by direct effects on fish and invertebrates or by indirect effects on other organisms by reducing their food sources. Also, by refining the assessment, the Agency w ould be able to determine whether the mitigation imposed as part of the registration review process was appropriate for alkyl imidazoline

.

If future endangered species risk assessments are performed without these data, the Agency would have

to assume tha t alkyl imidazoline "may affect" endangered species directly or indirectly, and use of alkyl imidazoline might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and regis trants have in coming into compliance with the Endangered Species Act and could result in use restrictions for alkyl imidazoline which are unnecessarily severe.

Acute freshwater invertebrate and fish toxicity data would be used to describe the concentrati on

response curves and determine 48

- h and 96

- h LC 50 ’s (concentrations calculated to kill 50% of the population) along with 95% confidence intervals. Additionally, a NOEC for 48 and 96 h are reported.

3) How could the data affect the risk assessment?

There are many freshwater invertebrates and fish species that are listed as threatened and endangered in the United States. Daphnia magna is considered as a surrogate species to represent all freshwater invertebrates in the risk assessment process. Oncorhynchu s mykiss (Rainbow trout) and Lepomis macrochirus (bluegill sunfish) are considered surrogate species to represent all freshwater fish species in the risk assessment process. As part of the acute risk assessment for aquatic animals, the lowest EC 50 or LC 50 for freshwater invertebrates and fish are used in the RQ equation. An acute RQ > 0.5 would indicate an acute LOC, defined as the potential for acute risk to non

target organisms which may warrant regulatory action in addition to restricted use classificati on. An acute RQ > 0.1 would result in an acute restricted use LOC, defined as the potential for acute

risk to non

- target organisms, which may be mitigated through restricted use classification. An acute RQ > 0.05 would fall under the LOC for acute endanger ed species.

4) What is triggering the need for this data? Data are needed in order to conduct an ecological risk assessment for the use of alkyl imidazoline as a microbiocide/microbiostat in fuel oil storage tanks and determine the acute toxicity of alkyl imidazoline to freshwater fish and invertebrates using acute toxicity studies.

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 alkyl imidazoline 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?Page 15 of 15 Guideline Number: 850.5400 Study Title: Algal toxicity (Tier II) using freshwater green alga, Selenastrum capricornutum
Practical Utility of the Data This study would be used to evaluate the toxicity of alkyl imidazoline to non

- target plants in terres trial 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 regu lators 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.