UNITED STATES ENVIRONMENTAL PROTECTION A GENCY

WAS HINGTON D.C.

, 20460

OFFICE OF

PREVENTION

, PESTICIDES AND

TOXIC SUBSTANCES

May 19,2010

MEMORANDUM



### Subject:

To:

From:

Reviewers:

Through: Registration Review

- Preliminary Problem Formulation for the Ecological Risk

and Drinking Water Exposure Assessments for Fosamine Ammonium 

### (PC Code: 106701; 

### DP Barcode: 372059)

Russell Wasem

, Chemical Review Manager

Risk Management & Implementation Branch 1

Pesticide Re-evaluation Division

Office of Pesticide Programs

.

### d,~~

Rochelle F. H.

# ~ohaty Ph.I?,

# c~emlsm~ '

. Donna R. Judkins, Ph.D., Biologist

### ;j 

### / "l

J

- Environmental Risk Branch 3 I I

Environmental Fate and Effects Division

Office of Pesticide Programs 

# t,

James Hetrick, Ph.D., Senior

# SCientist**i\ 't'**  . ' 

# ;

, 0-

. Pamela Hurley, Ph.D., Toxicologist

### ~~

Dana Spatz, Branch

### Chie~~~ Environmental Risk Branch

Environmental Fate and Effects ivision

Office of Pesticide Programs

The Environmental Fate and Effects Division (EFED) has completed the preliminary problem

formulation (attached) for the ecological risk, environmental fate

, endangered species, and drinking water assessments to be conducted as part of the Registration Review of the organophosphonate herbicide

, fosamine ammonium. This document is intended to provide an

overview of what is currently known regarding the environmental fate and ecological effects

associated with fosamine ammonium and its degradation products

, as well as outline

uncertainties regarding attributes of the parent compound and its transformation products. It

describes the preliminary ecological risk hypothesis and the processes that will be used during

the completion of drinking water and ecological risk assessments in support of Registration

Review.

### ii



# Problem Formulation for the Ecological Risk and Drinking Water Exposure Assessments in Support of the Registration Review of

Fosamine Ammonium

O P

NH 2 O O O NH 4



### Fosamine Ammonium (CAS 25954-13-6) ammonium ethyl carbamoylphosphonate

Prepared by: 

### Rochelle F. H. Bohaty, Ph.D., Chemist Donna R. Judkins, Ph.D., Biologist

Reviewed by: 

### James Hetrick, Ph.D., Senior Scientist Pamela Hurley, Ph.D., Toxicologist Dana Spatz, Branch Chief

Date May 19, 2010 U. S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division

Environmental Risk Branch 3 1200 Pennsylvania Ave., NW

Mail Code 7507P Washington, DC 20460

### iii 

### Table of Contents

I. Purpose ........................................

................................................... ............................................ 4 II. Nature of Regulatory Action....................

................................................... ............................... 4 A. Regulatory History..............................

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

B. Previous Risk Assessment.......................

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

III. Stressor Source and Distribution ..............

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

A. Mechanism of Action............................

................................................... ........................... 5 B. Overview of Pesticide Usage ....................

................................................... ....................... 6 C. Environmental Fate and Transport...............

................................................... .................... 6 Physical and Chemical Properties of Fosamine Ammoni um ................................................. 6 Environmental Fate Properties of Fosamine Ammonium

................................................... ... 7 Environmental Transport Mechanisms of Fosamine Ammo nium ........................................... 7 Monitoring Data

................................................... ................................................... ............. 10 IV. Receptors .....................................

................................................... ....................................... 10 A. Effects on Aquatic Organisms ...................

................................................... .................... 11 B. Effects on Terrestrial Organisms...............

................................................... ..................... 13 C. Adverse Ecological Incidents...................

................................................... ...................... 15 D. Ecosystems at Risk .............................

................................................... .......................... 15 V. Assessment Endpoints...........................

................................................... ............................... 15 VI. Conceptual Model...............................

................................................... ................................. 16 A. Risk Hypotheses................................

................................................... ............................. 16 B. Diagram........................................

................................................... .................................. 16

Direct Terrestrial Uses

................................................... ................................................... ... 16 VII. Analysis Plan Options .........................

................................................... ............................... 17 A. Ecological Risk Assessment .....................

................................................... ..................... 17 B. Endangered Species.............................

................................................... ........................... 18 C. Drinking Water Assessment......................

................................................... ..................... 18

D. Clean Water Act................................

................................................... ............................. 19 E. Anticipated Data Needs ..........................

................................................... ....................... 20 Other Information Needs

................................................... ................................................... 23

APPENDIX A.........................................

................................................... ................................... 24

APPENDIX B .........................................

................................................... ................................... 254



### I. Purpose

The purpose of this problem formulation is to provi de a better understanding of the environmental fate and ecological effects of the re gistered uses of fosamine ammonium.

Fosamine ammonium is a non-selective herbicide used to control undesirable brush/herbaceous plant species. This problem formulation uses a pre vious risk assessment as its basis. This document provides a plan for analyzing data relevan t to fosamine ammonium and for conducting an updated ecological risk assessment for its regis tered uses. Additionally, this problem formulation is intended to identify remaining data gaps, uncertainties, and potential assumptions

used to address those uncertainties relative to cha racterizing the ecological risk associated with the registered uses of fosamine ammonium.



### II. Nature of Regulatory Action

The Food Quality Protection Act (FQPA) of 1996 mand ated the EPA to implement a new program for assessing the risks of pesticides, i.e ., registration review. 1 

### All pesticides distributed or sold in the United States generally must be regi stered by EPA. The decision to register a pesticide is based on the consideration of scientif ic data and other factors showing that it will not

cause unreasonable risks to human health or the env ironment when used as directed on product labeling. The Registration Review program is inten ded to ensure that, as the ability to assess risk evolves and as policies and practices change, all r egistered pesticides continue to meet the statutory standard of no unreasonable adverse effec ts to human health and the environment. Changes in science, public policy, and pesticide us e practices will occur over time. Through the new Registration Review program, the Agency periodi cally reevaluates pesticides to ensure that as such changes occur; products in the marketplace can be used safely.

As part of the implementation of the new Registrati on Review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodentic ide Act (FIFRA), the Agency is beginning its

evaluation to determine whether fosamine ammonium c ontinues to meet the FIFRA standard for registration. This problem formulation for the env ironmental fate and ecological risk assessment chapter supporting the registration review is inten ded for the initial docket opening the public phase of the review process.

A. Regulatory History

Fosamine ammonium was first registered on August 12 , 1975 under EPA Registration No. 352- 376 (Du Pont Krenite® Brush Control Agent). It was registered for non-cropland (non-food) use areas such as railroads, pipeline, utility and high way right-of-ways, reforestation areas, drainage ditch banks, storage areas, industrial plants sites , and other similar sites.

A second product, EPA Registration No. 352-395, was registered on May 2, 1980. This product was registered under two trade names, DuPont Krenit e® S Brush 5 Control Agent and DuPont Krenite® UT Brush Control Agent. In addition to th e uses registered in 1975, forestry applications are included for this product.

1 http://www.epa.gov/oppsrrd1/registration_review/5



### The registrant’s request to cancel EPA Registration No. 352-376 (DuPont Krenite® Brush Control Agent) was approved and went into effect on June 22, 1994.

On August 23, 1994, DuPont filed an Application for Amended Registration, requesting voluntary cancellation of direct applications to wa ter, ditchbanks, and to other sites adjacent to and surrounding domestic water such as supply reser voirs, supply streams, lakes, and ponds.

In 1995, fosamine ammonium was the subject of a Rer egistration Eligibility Decision (RED) (EPA 738-R-95-004). All previous uses sites were e ligible for reregistration except aquatic sites.

The Agency approved a new label for DuPont Krenite® S Brush 5 Control Agent on June 5, 2006 (EPA Registration No. 352-395) which does not include aquatic use sites.

B. Previous Risk Assessment

The only risk assessment completed for fosamine amm onium since 1975 was completed in conjunction with the 1995 RED. Although fosamine a mmonium is highly soluble in water and mobile in various soils, the probability of it impa cting groundwater quality is low because fosamine ammonium degrades rapidly in the environme nt. Due to lack of definitive fate data, the environmental fate and transport of fosamine am monium transformation products were not evaluated at the time of reregistration. The Agen cy concluded in this assessment that fosamine ammonium products, labeled and used on sites as spe cified in the RED, do not pose

unreasonable risks of adverse effects to humans or the environment. For avian, mammalian, invertebrate, and aquatic studies the estimated ris k quotients (RQs) did not exceed the Agency’s levels of concern (LOCs). Acute risk to terrestria l plants could not be assessed at the time because data were still outstanding for corn, sugar beet, pea, and cucumber. Chronic exposure RQs for small mammals did not exceed Agency LOCs. Chronic data were unavailable for terrestrial plants and aquatic fish, invertebrates, and plants. The only level of concern exceeded (RQ = 23) was from a mallard reproduction study; ho wever, there is some uncertainly associated with the experimental results (D214645). EPA sugge sted modifying the label to account for the potential adverse effects on avian reproduction inc luding threatened and endangered species exposed to fosamine ammonium. This change is no lo nger an issue since EPA later (1997; per memo D231023) accepted a mallard reproduction study (MRID 44143501) showing the registered uses of fosamine ammonium do not result in RQs that exceed the Agency’s LOCs.



### III. Stressor Source and Distribution

A. Mechanism of Action

Fosamine ammonium is the ammonium salt of fosamine (CAS Number 25954-13-6; ammonium ethyl carbamoylphosphonate). It is an herbicide be longing to the organophosphonate class of pesticides. Fosamine is a non-selective herbicide used to control undesirable brush/herbaceous plant species. Mainly fosamine is used for brush c ontrol of nonagricultural rights-of-way (e.g., highways, railroads, and utilities), industrial sit es, and fencerows. Fosamine ammonium controls brush growth by inhibiting bud growth the year foll owing application. The exact mechanism of

action is unknown.6



### B. Overview of Pesticide Usage

Fosamine ammonium is used on a wide variety of terr estrial non-food and forestry applications. Target species include american elder, basswood, bi gleaf maple, birch, blackberry, black cherry, blackgum, black locust, bracken, chinese tallow, ch okecherry, eastern cottonwood, eastern pine, elm, field bindweed, hawthorn, hickory, leafy spurg e, loblolly pine, multiflora rose, persimmon, pin cherry, quaking aspen, red alder, red maple, re d oak, salmonberry, slippery elm, sassafras, sourwood, sumac, sweetgum, sycamore, thimbleberry, tree-of-heaven, tuliptree, vine maple, virginia pine, water oak, white ash, white oak, wil d grape, wild plum, winged elm, and willow.

Currently, fosamine ammonium is marketed under the trade name DuPont Krenite S Brush Control Agent. Krenite S is an end-use product for mulated as a 41.5% soluble fosamine ammonium liquid concentrate. The label calls for t he concentrate to be diluted in water. Based on the product label, application equipment include s helicopter and high or low volume ground sprayers. Uses include foliar, broadcast, high vol ume spray (dilute ≥ 1.5% by volume), low volume spray (concentrate, ≤ 30% by volume), and stump treatments. The maximum use rate for fosamine ammonium is 24 lbs a.i./A per year. For s ome uses, the single application rates are equal to the maximum annual treatment. Application use rates and methods for fosamine

ammonium are summarized in Appendix A . Application of fosamine ammonium directly to water is not permitted nor is application through a n irrigation system. Currently, fosamine ammonium is not registered for sale or use in Calif ornia or Arizona.

Pesticides with high water solubility, such as fosa mine ammonium, do not “wet” (cover) properly the waxy (hydrophobic) surfaces of plants. To attain proper coverage and distribution of the herbicide on plant surfaces, the label recom mends adding a surfactant or crop oil to the spray solution. The label also suggests adding an anti-foam agent if foaming is a problem during mixing.

No usage data were reported to the Environmental Fa te and Effects Division (EFED).

C. Environmental Fate and Transport

Physical and Chemical Properties of Fosamine Ammoni um

The physical and chemical properties of fosamine am monium are shown in Table 1 . Based on these physical and chemical properties alone, fosam ine ammonium has low potential to volatilize from soils (vapor pressure) or from water (Henry’s Law Constant). It is also unlikely to bioaccumulate in fish given the low value of the Lo g n -octanol/water partition coefficient.

Appendix B provides the chemical structures fosamine ammonium and its known degradates.7



### Table 1. Physical and Chemical Properties of Fosami ne Ammonium

Common name Fosamine Ammonium

Chemical name ammonium ethyl carbamoylphosphonate Pesticide type herbicide

Chemical class orthophosphonate

CAS number 25954-13-6 Empirical formula C 3 H 11 O 4 N 2 P Molecular mass (g/mol) 170.11

Vapor pressure 4 x 10 -6 mm Hg (25° C)

5.3 x 10 -3 Pa (25° C) Henry’s Law Constant 5.04 x 10 -7 PA m 3 /mol (calculated)

Solubility in water 1,795,000 mg L -1 (20°C) 1,790,000 mg L -1 (25° C) 1

K

ow 0.0012 (0.00104-0.00139) Melting Point 173-175 ° C (tech.)

1 http://www.invasive.org/gist/products/handbook/13.F osamine.pdf



### Environmental Fate Properties of Fosamine Ammonium

Fosamine ammonium is highly solubility in water. H owever, it does not break down by abiotic processes, such as hydrolysis and photolysis (MRIDs 40133701, 40133702, and 40133703). In the environment, its major route of dissipation is through rapid microbial-mediated degradation. One aerobic soil metabolism study indicates the hal f-life of fosamine ammonium is 0.5 days (MRID 42060601). Supplemental soil metabolism data indicate the half-life of fosamine ammonium can extend to 12 days depending on the soi l (MRID 141554). No aerobic aquatic

metabolism data have been submitted to the EPA. No degradation is observed for fosamine ammonium under anaerobic conditions (MRIDs 42060602 and 42680701). Major degradates (>10% of the applied) of fosamine ammonium are carb amolyphosphonic acid (CPA) and carboxylphosphonic acid (ING-3003), and carbon diox ide (MRIDs 42020206 and 42724301).

There is limited environmental fate data available for CPA and ING-3003.

Table 2 summarizes the environmental fate behavior of fosa mine ammonium and its degradates. These data are taken from studies submitted in supp ort of the registration or reregistration of

fosamine ammonium.

Environmental Transport Mechanisms of Fosamine Ammo nium

Fosamine ammonium is not expected to dissipate thro ugh volatilization from soil or water (MRID 42492201).

Fosamine ammonium has a low K

oc 

### indicating that it can leach to groundwater and tha t it can move to surface water at high levels through runoff . However, this scenario is unlikely due to rapid microbial-mediated degradation of fosamine am monium in soil.

For three of the four acceptable studies submitted to EPA, the calculated K d 

### for fosamine ammonium ranges from 0.11 to 0.14 and K

oc 

### ranges from 3 to 13 mL/g. Based on these8Table 2. Environmental Fate Data for Fosamine AmmoniumStudy/CurrentGuidelinesValueMajor Degradates1/CommentsMRIDClassificationHydrolysis835.21200, StableNone 40133701 AcceptablePhotodegradationin Water835.22400, StableNone40133702AcceptablePhotodegradationon Soil835.24100, StableNone 40133703 AcceptableLaboratoryVolatility835.1410<0.00631μg/cm2/hour<22μg/m3Fosamine ammonium (2% AR in soil)CPA (max 89% AR in soil)IN-G3003 (max 15% in soil)42492201 AcceptableAerobic SoilMetabolism835.4100t1/2= 0.5 to 12 daysCPA (max 94% AR immediately posttreatment)t1/2= 144 daysIN-G3003 (max 26% AR at 1 month posttreatment)t1/2= 34 daysTotal residue t1/2= 204 days; observed DT50= 220CO2(max at 33% at study termination)42060601141554AcceptableAnaerobicAquaticMetabolism835.4400t1/2= 2 daysCPA (max 59% AR at 14 days posttreatment)t1/2= 12 daysING-3003 (max 43% AR at 9 months posttreatment)CO2(max at 7.6% at 12 months--study termination)420606024268070142724301Acceptable9Study/CurrentGuidelinesValueMRIDClassificationSoil Kd(mL/g) Koc(mL/g)KF(ad)(μg1-1/n(cm3)1/ng-1)1/nKFoc(μg1-1/n(cm)1/ng-1)New Jerseysandy loam> 1 8.087 0.066 0.8603Woodstownsandy loam0.14 13.249 0.14 0.98 13.249Cecil sandyloam0.11 5.302 0.11 ~1 5.302Adsorption/Desorption(Batchequilibrium)835.1230Flanagan siltloam0.11 2.645 0.11 ~1 2.645424924014013370442492301AcceptableStudy/CurrentGuidelinesValueMajor Degradates1/CommentsMRIDClassificationTerrestrial FieldDissipation835.61001 d Lexington, TN1 d Newark, DE5 d Fayetteville, NCFosamine ammonium found predominantly inthe 0 to 15 cm soil samples.CPA (max at 26.7% at six weeks, DE siltloam; max at 40% at six weeks, IL silt loam;and 83% at two weeks, FL sandy loam)40955701 AcceptableFish BCF850.1730No accumulation observed therefore no BCFcould be calculated. A 9% observed mortality.42587601 Acceptable1Major degradates are defined as those that >10% ofthe applied.10



### K
oc 

### values, fosamine ammonium is classified as highly mobile according to the Food and Agriculture Organization (FAO) of the United Nation s classification scheme.

Terrestrial field data indicate that fosamine ammon ium degrades rapidly. This is

consistent with aerobic soil metabolism data.

Average concentrations of fosamine ammonium in blue gill sunfish is 0.337 mg/kg (whole fish), while 0.334 mg/kg is observed in fillet tissues and 0.348 mg/kg in viscera tissues. The K

ow 

### of fosamine ammonium is low (less than 0.0012). These data indicate fosamine ammonium

residues should not accumulate in fish tissues.

Monitoring Data

No surface or ground water monitoring data are avai lable for fosamine ammonium.



### IV. Receptors

Consistent with the process described in the Overvi ew Document, 2 

### the risk assessment for fosamine ammonium will rely on a surrogate species approach. Toxicological data generated from surrogate test species, that are intended to b e representative of broad taxonomic groups, are used to extrapolate potential effects on a variety of species (receptors) included under these taxonomic groupings.

Acute and chronic toxicity data from studies submit ted by pesticide registrants along with the available open literature are used to evaluate the potential direct and indirect effects of fosamine ammonium on aquatic and terrestrial receptors. Tox icity studies for the technical grade active ingredient (TGAI) and the typical end-use product w ill all be considered in the ecological risk assessment. Open literature studies are identified using EPA’s ECOTOX database 3 

### that employs a literature search engine for locating chemical to xicity data for aquatic life, terrestrial plants, and wildlife. Research papers accepted into the EC OTOX database are screened using standard procedures to ensure consistent, high quality infor mation; these studies will be considered during the ‘Analysis’ phase of risk assessment process. T he Ecological Incident Information System (EIIS, version 2.1) and the Avian Monitoring Inform ation System (AIMS) will be used to identify supportive, line of evidence information o n exposure of aquatic and terrestrial receptors. Data from all of these sources can also provide ins ight into the direct and indirect effects of

fosamine ammonium on biotic communities from loss o f species that are sensitive to the chemical and from changes in structure and function al characteristics of the affected

communities.

2 Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. Office of Pre vention,
Pesticides, and Toxic Substances. Office of Pestic ide Programs. Washington, D.C. January 23, 2004.

3 http://www.epa.gov/ecotox11



### A. Effects on Aquatic Organisms

Acute aquatic toxicity data are available for consi deration in this ecological risk assessment for fosamine ammonium; however, chronic toxicity data a re unavailable. Table 3 provides a summary of the taxonomic groups and the surrogate s pecies tested to characterize the potential acute and chronic aquatic effects of fosamine ammon ium.

Data from fish acute toxicity studies reviewed for the RED indicate that fosamine ammonium is practically nontoxic to coldwater and warm water fi sh (MRIDs 41607103, 41607102, and 00129075). The most sensitive LC 50 

### s for freshwater and saltwater fish, respectively, are 377 ppm a.i. for rainbow trout and >128 ppm a.i. for sh eepshead minnows (MRID 42715101), using technical grade fosamine ammonium. No data a re available from freshwater or estuarine/marine fish early life-stage or life-cycl e studies.

Fosamine ammonium is practically nontoxic to freshw ater and estuarine/marine

invertebrates on an acute basis. The most sensitiv e acute endpoint for freshwater

invertebrates is the Daphnia magna LC 50 

### of 1524 ppm a.i. using technical grade fosamine ammonium (MRIDs 00143492 and 92086005). The easter n oyster LC 50 

### is >122 ppm a.i. This study was also conducted using technical grade fosamine ammonium (MRID 42715102).

There are no chronic toxicity data available to ass ess the potential risk of fosamine ammonium and its major degradates to fish or aquatic inverte brates; this is a major source of uncertainty in the ecological risk assessment.

Tier I aquatic plant studies with both non-vascular and vascular plants (MRIDs 42902904 and 42587602, respectively) resulted in EC 50 

### s that are above the EEC in the most recent RED. The duckweed study, however, had an EC 40 

### at EEC.12Table 3. Aquatic Toxicity Profile for Fosamine AmmoniumStudy/Current GuidelinesTaxonExposureDurationMost Sensitive SpeciesTestedToxicityValuemg a.i./LAcute ToxicityCategory1MRIDClassification/CommentsFish Acute Toxicity Test,Freshwater and Marine850.1075Freshwater Fish AcuteRainbow trout,Oncorhynchus mykissLC50=377Practicallynontoxic41607103 AcceptableFish Acute Toxicity Test,Freshwater and Marine850.1075Estuarine/ Marine Fish AcuteSheepshead minnow,Cyprinodon variegatusLC50= >128Practicallynontoxic42715101 SupplementalAquatic InvertebrateAcute Toxicity Test,Freshwater Daphnids850.1010FreshwaterInvertebratesAcute Water Flea,Daphnia magnaLC50=1524Practicallynontoxic00143492 and92086005SupplementalOyster Acute Toxicity Test(Shell Deposition)850.1025Estuarine/ MarineInvertebratesAcute Eastern oysterLC50= >122Practicallynontoxic42715102SupplementalAlgal Toxicity,Tiers I and II850.5400Non-vascular plant Tier IAlga,SkeletonemacostatumEC25= >15NOAEC = 15Slightly toxic topracticallynontoxic42902904 AcceptableAquatic Plant ToxicityTest Using Lemna spp.,Tiers I and II850.4400Vascular plant Tier IDuckweed,Lemna gibbaEC50= >21(EC40= 21)NOAEC =<21Slightly toxic topracticallynontoxic42587602 Supplemental1Categories of acute toxicity for aquatic organisms(U.S. EPA, 2004) based on LC50(mg/L): < 0.1 very highly toxic; 0.1-1 highly toxic; >1-10 moderately toxic; >10-100 slightlytoxic; >100 practically nontoxic. Toxicity categories for aquatic plants have not been defined.13



### B. Effects on Terrestrial Organisms

Laboratory and field toxicity studies are available for characterization of the effects from acute exposures of fosamine ammonium to birds (also surro gate for terrestrial-phase amphibians and reptiles), mammals, and terrestrial invertebrates. Table 4 provides a summary of the most sensitive species tested for each terrestrial taxon omic group.

Data from the avian single-dose studies show fosami ne ammonium to be practically nontoxic to avian species on an acute basis, with LD 50 

### s of greater than 5000 mg/kg (the highest dose test ed)

for 99.4% TGAI fosamine ammonium in both mallard an d bobwhite quail (MRIDs 00093715 and 00130225, respectively). Exposure calculation s cited in the 1995 RED suggest that the right-of-way use may produce concentrations that ar e close to, and may exceed, 5000 ppm (5670 maximum residue on short grass from 24 lb a.i./A ap plication). This is an uncertainty, especially for passerine species which may be more sensitive, and for which we have no toxicity data.

Avian subacute toxicity data show fosamine ammonium to be practically nontoxic via dietary exposure. The LC 50 

### (>5620 ppm) is estimated to be greater than the hig hest dose tested for both mallards and quail (MRIDs 41891602 and 41891603, re spectively).

In the submitted avian reproduction study, the high est dose level tested, 11,600 ppm, did not produce effects. This is above the maximum EEC fro m the most recent risk assessment, 5760 ppm on short-grass.

The rat LD 50 

### for formulated fosamine ammonium is 24,400 mg/kg. This value characterizes the acute toxicity to mammals as practically nontoxic ( MRIDs 00075735 and 00026835).

Technical fosamine ammonium (95% a.i.) was shown to be practically nontoxic to the honey

bee. The estimated LD 50 

### is >200 μ g/bee (MRID 41215802).

Applications of fosamine ammonium at the registered rates may pose a significant risk to endangered plant species inhabiting treated rights- of-way. The test data were not calculated at the time of the RED due to lack of acceptable data. Data accepted since the RED show, upon preliminary risk assessment, that terrestrial plant s are under considerable risk especially from the right-of-way use (application rate 12 - 24 lb a.i./ A). Comparing the maximum application rate to the most sensitive plant acute endpoints presented in Table 4, result in acute RQs of 4 and 57 for seedling emergence and vegetative vigor, respective ly (MRIDs 42647601 and 43651101). This exceeds the Agency’s LOCs. 1 

### A complete risk assessment will be done during re gistration

review.14Table 4. Terrestrial Toxicity Profile for FosamineAmmoniumGuidelineTaxonExposureDurationMost SensitiveSpecies TestedToxicity ValueAcute ToxicityCategoryClassificationMRIDAcuteRatRattus norvegicusWaived; LD50>1954 mg a.i./Kg bw(adjusted for 97.7% purity) from acuteneurotoxicity study with no deaths upto HDT1(2000 mg tech/kg bw)PracticallynontoxicAcceptable42946501Mammal AcuteToxicity850.2400MammalsChronicRatR. norvegicusNOAEC = 200 mg/Kg/dLOAEC = 1000 mg/Kg/dN/ASupplemental00075736Avian Acute OralToxicity Test850.2100Acute OralNorthern bobwhitequail(Colinusvirginianus)Mallard(Anasplatyrhynchos)PasserineLD50= >5000 mg/Kg bwLD50= >5000 mg/Kg bwData GapPracticallynontoxicPracticallynontoxicSupplementalSupplemental0013022500093715Avian DietaryToxicityTest850.2200Sub-acuteDietaryQuail and mallard(C. virginianuandA. platyrhynchoss)>5620 ppm dietPracticallynontoxicSupplemental4189160241891603Avian ReproductionTest850.2300BirdsChronicReproductionMallardA. platyrhynchossNOAEC = 11,600 ppmLOAEC = >11,600 ppm(mg/Kg/d)PracticallynontoxicSupplemental44143501Honey Bee AcuteContact Toxicity850.3020TerrestrialInvertebratesAcuteHoney BeeApis melliferaLD50 = >200 ug a.i./beePracticallynontoxicSupplemental41215802Rape, shoot lengthinhibitionEC25= 2.3EC50= 5.8NOAEL = 1.5 lb a.i./acre42647601Terrestrial PlantToxicity,Tier II850.4100850.4150Tier II –SeedlingEmergenceVegetative VigorSoybean, totalweight inhibitionEC25= 0.099EC50= 0.42NOAEL = <0.094 lb a.i./acreN/AAll exceptsugarbeetacceptable436511011HDT = highest dose tested.15



### C. Adverse Ecological Incidents

A preliminary review of the Ecological Incident Inf ormation System (EIIS) 4 

### maintained by the Agency’s Office of Pesticide Programs (OPP) produce d one incident (I015280-001; June 4, 2004). According to the incident report spray drif t from the registered uses of fosamine ammonium “possibly” caused plant damage to cantalou pe (1 acre), tomato (2 acres) and watermelon (1-2 acres) crops. A search of the American Bird Conservancy’s databas e revealed

no incident data. 5 

### The reported incident suggests that exposure path ways for fosamine ammonium are complete and exposure levels sufficien t to result in field-observable effects.

D. Ecosystems at Risk

Fosamine ammonium may be applied as an aerial or gr ound spray herbicide to terrestrial habitats for agricultural uses, and as a spot treatment in n on-agricultural areas. The ecosystems potentially at risk are often extensive in scope; t herefore, it may not be possible to identify specific ecosystems at risk during the development of a nation-wide ecological risk assessment. However, in general terms, terrestrial ecosystems p otentially at risk could include the treated field and immediately adjacent areas that may recei ve spray drift or runoff. Areas adjacent to the treated field could include residential areas, cult ivated fields, fencerows, hedgerows, meadows, fallow fields, grasslands, woodlands, riparian habi tats, and other uncultivated areas.

Fosamine ammonium has the potential to contaminate surface water through spray drift and runoff. Aquatic ecosystems potentially at risk inc lude water bodies adjacent to, or down stream from a treated field. Such water bodies may includ e ponds, lakes, reservoirs, streams, rivers, and

estuaries.



### V. Assessment Endpoints

The most sensitive toxicity endpoints are used from surrogate test species to estimate treatmentrelated direct effects on acute mortality and chron ic reproductive, growth, and survival assessment endpoints. Surrogate aquatic organisms include freshwater and estuarine/marine fish and invertebrates. Surrogate terrestrial animal sp ecies include birds and mammals. The risk assessment also assumes that reptiles and terrestri al-phase amphibians are approximately as sensitive to pesticide-induced effects as birds. T hese tests include short-term acute, subacute, and reproduction studies. They are also typically arranged in a hierarchical or tiered system that progresses from basic laboratory tests to applied f ield studies. Incidents of toxicity from field

uses will also be considered as lines of evidence.

For plants in terrestrial and semi-aquatic environm ents, the screening assessment endpoint is the perpetuation of populations of non-target species ( crops and non-crop plant species). When data are available, endpoints assessed include emergence of seedlings and vegetative vigor. For aquatic plants, the assessment endpoint is the main tenance and growth of standing crop or biomass. When data are available, measurement endp oints for this assessment endpoint focus on

4 EIIS was accessed on January 12, 2010.

5 American Bird Conservancy database was assessed on January 13, 2010.16



### algal and vascular plant (i.e., duckweed) growth ra tes and biomass measurements. Incidents of phytotoxicity from field uses will also be consider ed as lines of evidence.



### VI. Conceptual Model

A. Risk Hypotheses

Risk hypotheses are specific assumptions about pote ntial adverse effects (i.e., changes in assessment endpoints) and may be based on theory, l ogic, empirical data, mathematical models, or probability models. 2 

### For this assessment, the risk is stressor-initiat ed, where the stressor is the

release of fosamine ammonium to the environment. T he following risk hypothesis is presumed for this screening-level assessment:

When used in accordance with current labels for ter restrial applications, fosamine ammonium and its degradates can move off-site via r unoff (both dissolved phase and with eroded sediment) and spray drift to expose non-targ et organisms. Application to foliar surfaces and soil may also result in exposure to no n-target organisms. These potential exposure pathways may result in adverse effects on the survival, growth, and/or reproduction of non-target terrestrial and aquatic organisms, including federally-listed threatened and endangered species.

B. Diagram

Direct Terrestrial Uses

The environmental fate properties indicate that run off of dissolved fosamine ammonium, erosion of fosamine ammonium bound sediment, and spray drif t represent potential transport mechanisms for fosamine ammonium and its degradates to aquatic and terrestrial organisms. As depicted in Figure 1 , these transport mechanisms ( e.g . sources) for spray (ground, aerial) applications may result in the movement of fosamine ammonium into aquatic (water) and terrestrial (soil and foliage) habitats. The movem ent away from the site of application represents exposure pathways for a broad range of biological r eceptors of concern (non-target animals) and the potential attribute changes, i.e. , effects such as reduced survivals, growth, and re production in the receptors.17



### Figure 1. Conceptual Model for Effects of Fosamine Ammonium on Non-target Aquatic and Terrestrial Organisms for Direct Terrestrial Us e Patterns



### VII. Analysis Plan Options

As part of Registration Review, pesticide ecologica l risk assessments will follow EPA’s Guidelines for Ecological Risk Assessment, 6 

### will be consistent with the EPA’s overview document, 2 

### and will be done in accordance with Section 7 of t he Endangered Species Act.

A. Ecological Risk Assessment

Previously completed risk assessments indicate that fosamine ammonium is practically nontoxic to aquatic and terrestrial animals and the register ed uses do not produce RQs that exceed the Agency’s LOCs. Use of fosamine ammonium may, howev er, directly affect terrestrial plants, especially from the right-of-way use (RQs = 4 and 5 7 for seedling emergence and vegetative vigor, respectively, see above) and through loss of food source, indirectly affect animals depending on terrestrial plants for food or habitat . The registered uses of fosamine ammonium do not result in RQs that exceed Agency LOC for aqu atic plants on an acute basis. Chronic risk

6 Guidelines for Ecological Risk Assessment, United S tates Environmental Protection Agency, Washington, D.C.: Government Printing Office. Available at http://cf pub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460 (A ccessed June 19, 2009). Stressor

Source/ Transport Pathways Volatilization/ Wind Suspension Direct Deposition Spray

Drift Runoff/

Erosion Leaching

(infiltration/ percolation)

Source/ Exposure
Media Terrestrial Food Residues (foliage, fruit, insects) Upland Foliage/Soil Riparian/

Wetland Foliage/Soil Water

Column/
Sediment Groundwater

Exposure
Point Ingestion Direct contact Direct contact Gill/ Integument Uptake

Receptors

Attribute Changes Terrestrial Vertebrates

Birds, Small Mammals, Reptiles, Terrestrial

Insects Terrestrial Upland

Plants

Individual Animals

Reduced survival Reduced growth Reduced reproduction Aquatic Invertebrates Aquatic Vertebrates Amphibians Aquatic Plants Wetland/ Riparian

Plants

Individual Plants Seedling emergence Vegetative vigor Individual

Vertebrates and

Invertebrates

Reduced

survival

Reduced growth

Reduced reproduction Food Web Exposure (biconcentration)

Piscivourous

Vertebrates Birds,

Mammals

Individual

Animals

Reduced survival, growth, and reproduction Plant Population

Reduced population growth Fosamine ammonium applied as ground/aerial spray in agricultural and residential settings.18



### to aquatic plants has not been assessed since none of the registered uses include direct application to water. If such uses are requested, chronic tests will be required.

Preliminary identification of data gaps include:

• Toxicity of fosamine ammonium to passerine bird spe cies (OPPTS Guideline 850.2100).

• Chronic toxicity and sublethal effects of fosamine ammonium to aquatic invertebrates and fish (OPPTS Guidelines 850.1300 and 850.1400).

B. Endangered Species

Consistent with the Agency’s responsibility under t he Endangered Species Act (ESA), EPA will evaluate risks to federally-listed threatened and/o r endangered (listed) species from registered

uses of fosamine ammonium. This assessment will be conducted in accordance with the

Overview Document 2 

### , provisions of the ESA, and the Services’ Endangered Species

Consultation Handbook 7



### .

The assessment of effects associated with registrat ions of fosamine ammonium is based on an

action area. The action area is considered to be t he area directly or indirectly affected by the federal action, as indicated by the exceedance of A gency LOCs used to evaluate direct or indirect effects. The Agency’s approach to defining the act ion area under the provisions of the Overview

Document 2 

### considers the results of the risk assessment proce ss to establish boundaries for that action area with the understanding that exposures b elow the Agency’s defined LOCs constitute a no-effect threshold. For the purposes of this asse ssment, attention will be focused on the footprint of the action ( i.e. , the area where fosamine ammonium application occu rs), plus all areas where offsite transport ( i.e. , spray drift and runoff) may result in potential e xposure that exceeds the Agency’s LOCs. Specific measures of ec ological effect that define the action area for listed species include any direct and indirect effects and/or potential modification of its critical habitat, including reduction in survival, growth, and reproduction as well as the full suite

of sublethal effects available in the effects liter ature. Therefore, the action area extends to a point where environmental exposures are below any m easured lethal or sublethal effect threshold for any biological entity at the whole organism, or gan, tissue, and cellular level of organization. In situations where it is not possible to determine the threshold for an observed effect, the action area is not spatially limited and is assumed to be the entire United States.

C. Drinking Water Assessment

A drinking water assessment has not been completed for fosamine ammonium. Prior to the enactment of FQPA, a drinking water assessment was not required for non-food use chemicals; therefore, a drinking water assessment will need to be completed as part of the human health

7 Endangered Species Consultation Handbook: Procedure s for Conducting Consultation and Conference Activi ties Under Section 7 of the Endangered Species Act. Fin al Draft, United States Fish and Wildlife Service ( USFWS) and National Marine Fisheries Service (NMFS). Washingto n, D.C.: Government Printing Office. Available at http://www.fws.gov/endangered/consultations/s7hndbk /s7hndbk.htm (Accessed June 19, 2009).19



### dietary risk assessment. Tier I Estimated Drinking Water Concentrations (EDWCs) for human health assessments will be estimated using EFED’s a quatic models FIRST (F QPA I ndex

R eservoir S creening T ool, version 1.0, August 1, 2001) for surface water and SCI-GROW (S creening C oncentration i n Gro undw ater, version 2.3, August 8, 2003) for ground water

. 8



### If needed, Tier II EDWCs in surface water will be e stimated using PRZM (P esticide R oot Z one
M odel, version 3.12.3, June 2006) and EXAMS (EX posure A nalysis M odeling S ystem, version 2.98.04.06, April 2005) models in the PE5 shell. P RZM is used to simulate pesticide transport in soil within and immediately below the plant root zo ne. EXAMS estimates the fate, transport, and exposure concentration of pesticides in an inde x reservoir from surface water for an agricultural watershed. 8



### D. Clean Water Act

Fosamine ammonium is not identified as a cause of i mpairment for any water bodies listed as impaired under section 303(d) of the Clean Water Ac t, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation_ cy.cause_detail_303d?p_cause_group_id=885

. 

### In addition, no Total Maximum Daily Loads (TMDL) ha ve been developed for fosamine ammonium, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation. tmdl_pollutant_detail?p_pollutant_group_id =885&p_pollutant_group_name=PESTICIDES . More information on impaired water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/

.

EPA invites submission of water quality data for th is 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 Oth er 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.

8 

### http://www.epa.gov/oppefed1/models/water/index.htm

.20



### E. Anticipated Data Needs

Guideline Number: OPPTS 850.2100 Study Title: Avian Acute Oral Toxicity Test Species: Passerine Species Rationale for Requiring the Data

Acute risk to passerines as a result of exposure to fosamine ammonium has not been considered in previous assessments since there are no acute oral toxicity data available. Current Part 158 data requirements (CFR 40 2007) specify that acute avian oral toxicity data be submitted for either mallard duck or bobwhite quail AND a passerine species. (A protocol for the acute oral toxicity test with the house sparrow should be submitted to the Agency pri or to test initiation.) Without this study, the Age ncy would have to presume risk to listed and non-listed passerines, and would not be able to quantify the risk.

Practical Utility of the Data

How will the data be used?

Acute oral avian toxicity data will be used to quan titatively estimate the risk of fosamine ammonium t o birds (and terrestrial-phase amphibians and reptile s) and to define an action area for endangered spec ies and explore risk mitigation strategies. These toxi city data will reduce uncertainties associated with the risk assessment for passerines. In the absence of data on fosamine ammonium, quantitative risk estimation will not be possible. Therefore, determ ination of the distance from a treated field to whi ch the risk to passerines may extend and application rate reductions resulting in no LOC exceedances cannot b e quantified without these data. 

### The current method of calculating a weight-adjust ed LD 50 

### using bobwhite quail or mallard duck data may over- or un der-estimate risks to passerines because these birds may metabolize the chemical differently

.

How could the data change the Agency’s decision or impact the Agency’s future decision-making?

The value of these acute oral toxicity studies woul d be in quantifying and potentially refining risks to passerine birds. Defining an action area for endan gered species and exploring risk mitigation strateg ies for passerines cannot be accurately evaluated witho ut these data. If future endangered species risk assessments are performed without these data, the A gency will assume that fosamine ammonium “may affect” passerines directly, and use of fosamine am monium may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use

restrictions for fosamine ammonium which are unnece ssarily severe. 

### Because the 850.2100 guideline has not yet been finalized, protocols for the study of passerine species should be submitted to EPA for approval prior to study initiation.21

Guideline Number: 850.1400
Test Substance: Fosamine Ammonium Study Title: Fish Early Life-Stage (freshwater) Test Species: Rainbow trout ( Oncorhynchus mykiss) or Bluegill sunfish ( Lepomis macrochirus ) Rationale for Requiring the Data

The freshwater fish early life-stage test using TGA I is currently listed as “Required” in 40 CFR part 158 for all out-door uses, unless they are onl y residential (exclusion does not apply to turf).

Data are required on one freshwater fish species. If the test species is different from the two species used for the freshwater fish acute toxicity tests, a 96-h LC 50 on that species must also be provided.

Without this study, the Agency would have to presum e chronic risk to listed and non-listed fish, but would not be able to quantify the risk.
Practical Utility of the Data

How will the data be used? The freshwater fish early life-stage test data woul d allow the Agency to refine the screening level risk assessment for Registration Review. The stud y would allow the Agency to analyze chronic effects, including effects on reproductive success and growth, to fish. The effects data would be

used to determine the likelihood that the chronic r isks can potentially impact aquatic communities, either by direct effects on fish or by indirect effects on fish and other organisms

that feed on them.

This data will, in turn, be used to calculate a fis h ACR for fosamine ammonium, which will be applied to the saltwater fish acute data to calcula te a more refined chronic saltwater fish toxicity endpoint.

How could the data impact the Agency’s future decis ion-making? If future endangered species risk assessments are p erformed without these data, the Agency would have to assume that fosamine ammonium "may af fect" fish directly and other taxa that feed on fish, indirectly. The use of fosamine amm onium might need to be restricted in areas where these species could be exposed. The lack of these data would limit the flexibility the Agency and registrants have and could result in unn ecessarily severe use restrictions for fosamine

ammonium.22

Guideline Number: 850.1300
Test Substance: Fosamine Ammonium Study Title: Aquatic Invertebrate Life-Cycle (freshwater) Test Species: Water Flea ( Daphnia magna ) Rationale for Requiring the Data

The freshwater invertebrate life cycle test using T GAI is currently listed as “Required” in 40 CFR part 158 for all out-door uses, unless they are onl y residential (exclusion does not apply to turf).

Data are required on one freshwater invertebrate sp ecies.

Without this study, the Agency would have to presum e chronic risk to listed and non-listed aquatic invertebrates, but would not be able to qua ntify the risk.
Practical Utility of the Data

How will the data be used? The freshwater invertebrate life cycle test data wo uld allow the Agency to refine the screening level risk assessment for Registration Review. The study would allow the Agency to analyze chronic effects, including effects on reproductive success and growth, to freshwater invertebrates.

The effects data would be used to determine the lik elihood that the chronic risks can potentially impact aquatic communities, either by direct effect s on invertebrates or by indirect effects on fish and other organisms that feed on them.

This data will, in turn, be used to calculate an aq uatic invertebrate ACR for fosamine ammonium, which will be applied to the saltwater invertebrate acute data to calculate a more refined chronic saltwater invertebrate toxicity endpoint.

How could the data impact the Agency’s future decis ion-making? If future endangered species risk assessments are p erformed without these data, the Agency would have to assume that fosamine ammonium "may af fect" aquatic invertebrates directly and other taxa that feed on them, indirectly. The use of fosamine ammonium might need to be restricted in areas where these species could be ex posed. The lack of these data would limit the flexibility the Agency and registrants have and cou ld result in unnecessarily severe use

restrictions for fosamine ammonium.23 

### Other Information Needs

There is specific information that will assist EPA in refining the ecological risk assessment, including any species-specific effects determinatio ns. EPA is interested in obtaining the following information:

1. confirmation on the following label information a. sites of application

b. formulations c. application methods and equipment d. maximum application rates e. frequency of application, application intervals, and maximum number of applications per season f. geographic limitations on use 2. use or potential use distribution (e.g., acreage and geographical distribution of relevant crops) 3. use history

4. median and 90 th 

### percentile reported use rates (lbs ai/acre) from u sage data – national, state, and county 5. application timing (date of first application an d application intervals) by crop – national, state, and county 6. sub-county crop location data 7. usage/use information for non-agricultural uses (e.g., forestry, residential, rights-of-way) 8. directly acquired county-level usage data (not d erived from state level data) a. maximum reported use rate (lbs ai/acre) from usa ge data – county b. percent crop treated – county

c. median and 90 th 

### percentile number of applications – county d. total pounds per year – county e. the year the pesticide was last used in the coun ty/sub-county area f. the years in which the pesticide was applied in the county/sub-county area 9. typical interval (days)

10. state or local use restrictions 11. ecological incidents (non-target plant damage a nd avian, fish, reptilian, amphibian and mammalian mortalities) not already reported to the Agency 12. monitoring data

The analysis plan will be revisited and may be revi sed depending upon the data available in the open literature and the information submitted by th e public in response to the opening of the Registration Review docket.24



### APPENDIX A

Maximum Fosamine Ammonium Use Rate and Management P ractices
(Generalized Screening Level Portrayal of Current L abel Uses. Source: current label; accepted June 5, 2006)



### Group name Uses represented Max. Rate per App. (lb a.i./A) Seasonal

Max.

Dose/Year (lb) 1 

### Application

Method 2



### Terrestrial

Non-Food Crop Agricultural and

nonagricultural right-ofway/fencerows/hedgerows

Agricultural uncultivated

areas

Airports/landing fields

Industrial areas (outdoor)

Nonagricultural

uncultivated areas/soils

Sewage disposal areas 24 12 (aerial) 24 (ground) Aerial and

ground

Forestry Pine (forest/shelterbelt) 6 12 Aerial and ground

1 Application methods reported for any labeled applic ation rates (maximum rate per application and/or se asonal maximum dose/year) for that crop/use. The term gro und includes any of the ground methods previously d efined as ground. In some cases when both aerial and ground application methods are reported for a crop/use, b oth methods may not be used at the maximum reported application rates (single application and/or seasonal applicat ion).

2 Aerial refers to helicopter application only.25



### APPENDIX B

Chemical Structures

Fosamine Ammonium; DXP-R1108

O P

NH 2 O O O NH 4



### Carbamoylphosphonic Acid; CPA; INT-3691

O P

NH 2 O O O



### Carboxylphosphonic Acid; ING-3003

O P

O O O O