### 1 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

MEMORANDUM Date 12/ 09 /201 5 Subject: Registration Review

– Preliminary Problem Formulation for Ecological Risk and

Environmental Fate, Endangered Species, and Drinking Water As sessments for

Di phacinone and Diphacinone Sodium Salt

PC Code s : Diphacinone 067701

Diphacinone Sodium Salt 067705

DP Barcode : 426286

To: Christina Motilall

, Chemical Review Manager

Neil Anderson

, Branch Chief Risk Management and Implementation Branch 1

Pesticide Re

- evaluation Division ( PRD )

From: Christine Hartless

, Ph.D., Wildlife Biologist

James Lin , Ph.D., Environmental Engineer

Environmental Risk Branch 2

Environmental Fate and Effects Division Office of Pesticide Programs

Through: Melissa Panger, Ph.D., Senior Advisor

Ron Parker, Senior Environmental Engineer Elyssa Arnold, Risk Assessment Process Leader

Brian Anderson

, Branch Chief

Environmental Risk Branch 2

Environmental Fate and Effects Division Office of Pesticide Programs

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

formulation (attached) for the ecological risk, environmental fate, endangered species

, and drinking water assessment s to be conducted as part of the registration r eview of the rodenticide s di phacinone (PC Code 067701) and diaphacinone sodium salt (PC Code 067705)

.

The problem formulation draws on information from both open literature and studies submitted by the technical registrants in response to data requirements. This document is intended to provide an overview of what is currently known regarding the environmental fate and ecological

effects associated with di phacinone and its sodium salt and outlines 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

### 2

water and ecological risk assessments in support of registration review

. This document also

recommends studies that should be included in a data call

- in (DCI) to address uncertainties surrounding the environmental fate and potential ecolog ical effects of di phacinone and diphacinone sodium salt

.

### 3



# Preliminary Problem Formulation for the Environmental Fate and Ecological Risk , Endangered Species

, a nd Drinking

Water Assessment s in Support of the R eg istration Review of

Di phacinone and Diphacinone Sodium Salt

Diphacinone

2

- (diphenylacetyl)indan

- 1,3

- dione

(CAS 82

- 66

- 6) (PC Code 067701) Diphacinone sodium salt

2

- (diphenylacetyl)indan

- 1,3

- dione, sodium

(CAS 42721

- 99

- 3) (PC Code 067705)

Environmental Risk Branch II Environmental Fate and Effects Division Christine Hartless, Ph.D., Wildlife Biologist James Lin, Ph.D. Environmental Engineer

Reviewed by: Melissa Panger, 

### Ph.D., Senior Advisor

Ron Parker

, 

### Senior Environmental Engineer Elyssa Arnold, Risk Assessment Process Leader
Brian Anderson, Branch Chief U. S. Environmental Protection Agency Office of Pesticide Programs 1200 Pennsylvania Ave., NW

Mail Code 7507P Washington, DC 20460

December 9, 2015

### 4 Table of Contents

1 EXECUTIVE SUMMARY

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

2 INTRODUCTION

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

3 USE CHARACTE RIZATION

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

4 CONCLUSIONS FROM PRE VIOUS RISK ASSESSMEN TS

................................ ................................ .................. 10

4.1 E NDANGERED S PECIES A SSESSMENTS

................................ ................................ ................................ ..................... 10

4.2 R EREGISTRATION E LIGIBILITY D ECISION

................................ ................................ ................................ ................... 10

4.3 N EW U SE A SSESSMENTS

................................ ................................ ................................ ................................ ...... 11

4.4 D RINKING WATER ASSESS MENT

................................ ................................ ................................ ............................. 12

5 ENVIRONMENTAL FATE A ND TRANSPORT

................................ ................................ ................................ .. 12

5.1 T RANSPORT AND M OBILITY

................................ ................................ ................................ ................................ .. 12

5.2 D EGRADATION

................................ ................................ ................................ ................................ ................... 13

5.3 T RANSFORMATION P RODUCTS

................................ ................................ ................................ .............................. 14

6 RECEPTORS

................................ ................................ ................................ ................................ ................. 15

6.1 T OXICITY S UMMARY

................................ ................................ ................................ ................................ ........... 15

6.2 S ECONDARY T OXICITY

................................ ................................ ................................ ................................ .......... 17

6.3 I N CIDENT D ATABASE R EVIEW

................................ ................................ ................................ ................................ 21

7 EXPOSURE PATHWAYS OF CONCERN

................................ ................................ ................................ .......... 21

8 ANALYSIS PLAN

................................ ................................ ................................ ................................ ........... 22

8.1 S TRESSOR S OF C ONCERN

................................ ................................ ................................ ................................ ...... 22

8.2 M EASURES OF E XPOSURE

................................ ................................ ................................ ................................ ..... 22

8.3 M EASURES OF E FFECT

................................ ................................ ................................ ................................ ......... 30

9 ENDANGERED SPECIES A SSESSMENT

................................ ................................ ................................ .......... 30

10 ENDOCRINE DISRUPTOR SCREENING PROGRAM

................................ ................................ ......................... 30

11 PRELIMINARY IDENTIFI CATION OF DATA GAPS

................................ ................................ ........................... 31

11.1 F ATE

................................ ................................ ................................ ................................ ........................... 31

11.2 E FFECTS

................................ ................................ ................................ ................................ ....................... 31

12 REFERENCES

................................ ................................ ................................ ................................ ............... 35

APPENDIX A: LABEL US E INFORMATION FOR DI PHACINONE AND DIPHAC INONE SODIUM SALT BA SED ON BEADS

SUMMARY REPORT

................................ ................................ ................................ ................................ .............. 46

APPENDIX B: SUMMARY OF ECOTOXICITY DATA FOR DIPHACINONE

................................ ................................ ... 48

APPENDIX C. SCREENI NG LEVEL MODELS TO E VALUATE POTENTIAL IM PORTANCE OF DRINKING WATER AND

INHALATION EXPOSURE PATHWAYS

................................ ................................ ................................ .................... 50

APPENDIX D. WILDLIF E MORTALITY INCIDENT S ATTRIBUTED TO USE OF DIPHACINONE

................................ ..... 53

### 5



# 1 Executive summary

The Environmental Fate and Effects Division (EFED) has completed the preliminary problem formulation for the ecological risk, environmental fate, endangered species, and drinking water assessments to be conducted as part of the registration review of di phacinone ( PC code 067701)

and diphacinone sodium salt ( PC code 067705 )

. Diphacinone sodium salt easily and quickly converts to diphacinone by hydrolysis in the environment. Therefore, all environmental fate and toxicity data for diphacinone (067701) will be bridged to diphacinon e sodium salt (067705)

.

For this registration review, the stressor of concern for drinking water, terrestrial organisms, and aquatic organisms is diphacinone (067701) only. For clarity throughout this Problem Formulation, “diphacinone (067701)” will be u sed to refer specifically to 2

- (diphenylacetyl)indan

- 1,3

- dione, “diphacinone sodium salt (067705) ” will be used to refer specifically to 2

- (diphenylacetyl)indan

- 1,3

- dione, sodium, and “diphacinone” will be used to refer collectively to diphacinone (067701) and/ or diphacinone sodium salt (0677 05).

The problem formulation describes the methods planned to be used during the completion of drinking water and ecological risk assessments in support of registration review and provides an

overview of the environme ntal fate, ecological effects, and potential risks associated with the use

of di phacinone as well as uncertainties unique to risk assessment of di phacinone

. This document

also identifies additional studies that would be beneficial to the conduct of an ecol ogical risk

assessment.

Data requested to address ecological effect uncertainties are:

 Avian acute oral toxicity test (850.2100), one passerine species

 Avian reproduction toxicity (850.2300), for two species

 Prenatal Developmental Toxicity Study (870.3700) or Reproduction and Fertility Effects Study (870.3800)

, one species

 Earthworm Subchronic Toxicity Test (850.3100), one species

 D ata evaluating toxicity and/or bioaccumulation of diphacinone in terrestrial

invertebrates

N o additional d ata are requested for the environmental fate assessment at this time.



# 2 Introduction

Di phacinone (067701) and its sodium salt (067705) are indandione anticoagulant rodenticide s and are classified as first

- generation anticoagulants. Anticoagulants are vitamin

- K antagonists that disrupt normal blood

- clotting mechanisms and induce capillary damage. They uncouple oxidative phosphorylation depressing hepatic synthesis of prothrombin and clotting factors VII,

IX and X an d cause direct damage to capillary permeability. Typically, death is delayed for four to ten or more days after a lethal dose is ingested, and animals may continue to feed and move about until shortly before death. Dea th results from hemorrhage, and exposed animals may exhibit behavior that may make them more susceptible to predation (Cox and Smith

, 1992). This may result in secondary exposure to predatory animals. Some of the consumed d i phacinone will

### 6

be excreted or m etabolized by animals that have eaten bait, but some is sequestered in various body tissues for days or weeks.

The anticoagulant rodenticide s registered in the United States have been grouped into "first

generation" (warfarin, chlorophacinone, diphacinon e) and "second

- generation" (brodifacoum,

d ifenacoum

, bromadiolone, difethialone) compounds. Although there is overlap in their metabolic and toxicological properties, s econd

- generation anticoagulants tend to be more acutely

toxic than are the first

- genera tion anticoagulants, and they are retained longer in body tissues. The greater potency and duration of action of long

- acting anticoagulant rodenticides is attributed to their: (i) greater affinity for vitamin K(1)

- 2,3

- epoxide reductase; (ii) ability to dis rupt the vitamin K(1)

- epoxide cycle at more than one point; (iii) hepatic accumulation; and (iv) unusually long biological half

- lives due to high lipid solubility and enterohepatic circulation (Watt et al. 2005).

EFED evaluated the most recent ecologica l risk assessments for di phacinone in association with the updated toxicity, exposure, and usage information to determine if sufficient data are available and if further updates are needed to support registration review. In addition, EFED considered

the l atest Agency science policies and risk assessment methodologies. Any additional relevant data that become available at the time of the registration review will be incorporated into the

assessment. The structure of di phacinone and its sodium salt , as well as the chemical names and other identifiers can be found in the chemical identity table in Section 5 of this document.



# 3 Use Characterization

Table 1 summarizes the use patterns and bait concentrations for given groups of target species.

Details for individual products are not included; however, this table provides characterization for the expected use patterns of diphacinone (067701) and diphacinone salt (067705)

. In ad dition to

the Section 3 labels summarized in Table 1 , there are currently eig ht Section 24C labels for diphacinone (067701) :

 target species of Norway rats, roof rats, wood rats, deer mice, California and montane voles, California ground squirrels, chipmunks, black tailed jackrabbits, and muskrats in California;

 Norway and black rats in Alaska;

 wood rats in Arizona;

 small Indian mongoose ( Herpestes auropunctatus ), roof rats, Norway rats, Polynesian rats ( R. exulans ), and house mice ( Mus musculus ) in Hawaii ;

 Columbian ground squirrel ( Spermophilus columbianu s) and Richardson's g round squirrel ( S. richardsoni ) in Montana; and

 a 0.01% diphacinone bait for California Ground Squirrels ( Spermophilus beecheyi ), Belding's Ground Squirrels ( S. beldingi ), deer mice ( Peromyuscus spp.), and house mice

in Cali fornia.

Since there is no national level usage data for this chemical, no Screening Level Usage Analysis (SLUA) is available for diphacinone (067701) or diphacinone sodium salt (06 77 05). Appendix

A lists the maximum use patterns for the labeled use sites for diphacinone (067701) an d for

### 7

diphacinone sodium salt (067705). The table is based on the “EFED Table 1 Report,” which is a part of the Label Use Report Package created by BEAD in support of Registration Review (USEPA, 2015). Prior to the registration review assessment, the labe l review will be updated.

### 8

Table 1. Overview of Section 3 Labels for Diphacinone (067701) and Diphacinone sodium salt (067705)

Target Species % a.i. Bait form General Use P attern Use Sites Maximum application rate and re

application interval Diphacinone

House mouse ( Mus

musculus ), Roof rat ( Rattus rattus ), Cotton rats ( Sigmodon hispidus ),

Eastern harvest mouse ( Reithrodontomys

humuli ), Golden mouse ( Ochrotomys nuttalli ), Polynesian rat ( Rattus

exulans ), and/or Meadow vole ( Microtus pennsylvanicus ). 0.005 Bait block, pellet, treated grain, place pack Use indoors and within 100

feet of man

- made

structures. Must use bait

station for outdoor above ground use or when

children or non

- target
mammals or birds can

access the bait. Some labels restrict use indoors;

some restrict to within 50

feet of man

- made structure. Indoor and within

100 feet or within

50 feet of man

made structures (residential, commercial, agricultural, industrial, public buildings, ships/boats) Refill/replace bait boxes as needed.

House mouse, Norway rat, and Roof rat 0.2 Tracking powder Use indoors or in rat

burrows leading indoors. Indoor or in rat burrow leading

indoors. Repeat if burrows are reopened. Maintain

powder in treat ed areas for at least 20 days.

0.1 Concentrate to

be mixed in bait. Resulting

concentration of diphacinone in

final bait is

0.005%. Use in and within 100 feet

of man

- made structures.

Must use bait station for outdoor above ground use

or when children or non

target mammals or birds

can access the bait. Indoor and within

100 feet of man

made structures. Maintain bait station for 10 (rat) or 15

(mouse) days. Can establish permanent station if pest pressure continues.

Pocket gopher ( Geomys

spp

. and Thomomys spp.) and/or moles ( Scalopus aguaticus

, Condylura

cristata , and Scapanus spp.) 0.005 Pellet or treated grain Applied underground to

burrow system by hand or by mechanical burrow

builder Agricultural crop

and non

- crop areas, orchards, rangeland, forest,

orn amental turf, golf courses, crop borders, parks. Not specified.

Meadow voles ( Microtus pennsylvanicus ) and pine voles ( M. pinetorum ) Bait station, hand broadcast, mechanical ground broadcast, aerial

broadcast Commercial nurseries, dormant

fruit tree orchards Broadcast application

– apply 10 lbs.

product/acre with 2 nd application one month later, if needed. For some labeled sites, max application rate of 20 lbs product/acre/application.

### 9

Table 1. Overview of Section 3 Labels for Diphacinone (067701) and Diphacinone sodium salt (067705)

Target Species % a.i. Bait form General Use P attern Use Sites Maximum application rate and re

application interval

For California ground squirrel ( Spermophilus beechyi ) and/or Townsend ground squirrel ( Urocitellus townsendii) Bait station, hand broadcast, or mechanical ground broadcast around buildings,

in non crop areas (s uch as a long

levees and ditch banks, along fence lines), in rangeland and pasture land, and in crop areas (such as dormant orchards) , parks, golf courses Bait station : 2

- 4 lbs bait/station. Bait to be

available for at least 30 days or till feeding

stops. Broadcast 70 gms product near burrow.

Re

- apply every 2

- 3 days for 3

- 4 total applications.

Black tailed pr airie dog ( Cynomys ludovicianus) Place 1/4 cup bait at least 6

inches into each burrow Rangeland and adjacent non

- crop

areas If needed, may make second application

several weeks or months later.

Norway rats, roof rats, Polynesian rats, house mice or other types of

invasive rodents for

control or eradication. For conservation purposes on islands, grounded vessels or vessels in peril of grounding. 0.005 Pellet Bait stations, burrow baiting, canopy bailing or aerial and gr ound broadcast application techniques. Conservation reserve lands, forest, ships, boats, shipholds. Bait station : Maintain an uninterrupted

supply of fresh bait for at least 15 days or until signs of rodent activity cease. Where a

continuous source of infestation is present, permanent bait stations may be used

. Burrow baiting

- place 85 to 113 g bait in each burrow; maintain bait for at least 15 days or till rodent activity stops. Canopy baiting : 113

- 200 gm bait in bag per placement, no mention of retreatment.

Broadcast : 10

– 12.5 lbs bait/acre with second application 5

- 7 days later. Or si ngle application at max of 20 lb s product/acre. Diphacinone sodium salt (067705)

House mouse, Norway

ra t, and Roof rat 0.106% Liquid

concentrate to
be mixed in water. Resulting

concentration of diphacinone in

final bait is

0.005%. Put liquid solution in bait

boxes. For indoor use only. For use inside of industrial, commercial, agricultural, and public buildings,

and similar man

made structures. Can establish permanent bait stations if

necessary.

### 10



# 4 Conclusions from Previous Risk Assessments

The Agency has conducted previous ecological risk assessments on di phacinone that serve as a

basis fo r this problem formulation. They are briefly summarized below.



## 4.1 Endangered Species Assessments

An endangered species risk assessment was completed for diphacinone (067701) in 2011 (USEPA 2011) to address potential risk to the Salt marsh harvest mouse (SMHM) ( Reithrodontomys raviventris ), San Joaquin Kit Fox (SJKF) ( Vulpes macrotis mutica ), Alameda Whipsnake (AW) ( Masticophis lateralis euryxanthus ), and California Tiger Salamander (CTS) ( Ambystoma californiense ) for which diphacinone was alleged to be o f concern in a complaint made by the Center for Biological Diversity against United States Environmental Protection Agency on May 30, 2007 (Case No: 07

- 2794

- JCS)

. Based on the best available information, the Agency made a “ May Affect, and Likely to Adverse ly Affect” determination for the SMHM, SJKF, AW, and CTS from all uses of diphacinone. Additionally, the Agency determined that there was the potential for modification of designated critical habitat for the AW and CTS from the use of diphacinone.



## 4.2 Reregist

ration Eligibility Decision

The Reregistration Eligibility Decision (RED) for diphacinone was published in 1998 as part of the rodenticide cluster (USEPA, 1998b). The RED found that all uses of diphacinone except for field rodenticide uses involving bait s with diphacinone concentrations greater than 0.005% were eligible for reregistration. In addition, the RED found that all rodenticides must incorporate an indicator dye and a bittering agent. Both these measures were intended to help reduce human

exposur e. Other mitigation measures included improved label language regarding placement of bait stations around buildings, submission of information on poisonings, restricted use classification of tracking powders and baits, and the formation of a stakeholder gr oup to investigate safer use technologies.

“Potential Risks of Nine Rodenticides to Birds and Nontarget Mammals: a Comparative Approach” (USEPA 2004b) evaluated primary and secondary exposure of diphacinone, among other rodenticides, to birds and mammals . This assessment determined that the greatest risk of diphacinone use to non

- target animals is via primary and secondary exposure to mammals. Risk associated with primary and secondary exposure to birds, however, was also of concern. These elements pro vide the general framework for this assessment and are supported through the calculation of RQs in this assessment. The study also specified a number of factors contributing to uncertainty in assessing anticoagulant rodenticides. Those

factors that contr ibuted the most uncertainty were: (1) missing data, including acute, chronic, and secondary toxicity as well as data regarding retention of some active ingredients in the liver, blood, and other body tissues; (2) the variable quality and quantity of

existi ng data on metabolism and retention times in rodents and non

- target species; (3) specific use information by formulation, including typical amounts applied by use site, seasonally, and annually; distances applied from buildings; amounts used in rural versu s

### 11

urban areas; use by Certified Applicators versus homeowners and other non

- certified applicators; and other such relevant information; (4) information on the number and species

of birds and non

- target mammals frequenting baited areas and the likelihood of their finding and consuming bait or poisoned primary consumers in the various use areas; (5) methods to determine liver concentration(s) and total body burdens of rodenticide that would

corroborate death or even if such a cause

- effect relationship is appr opriate ( e.g ., the “threshold of toxicity” concentration); (6) not accounting for the impacts of sub

- lethal effects on reproduction and non

- target mortality ( e.g ., clotting abnormalities, hemorrhaging, stress factors including environmental stressors, such as adverse weather conditions, food shortages, and predation); (7) not accounting for bioaccumulation of repeated sub

- lethal exposures to bait or poisoned rodents utilized as food by predators and scavengers; and (8) lack of incident reporting. While all of these uncertainties remain, the level of uncertainty has been reduced through the use of additional data submitted by the registrant or available

in the scientific literature.

In 2008, EPA released the Risk Mitigation Decision for Ten Rodenticides (R MD) (EPA 2008,

Docket ID EPA

- HQ

- OPP

- 2006

- 0955 ). Di phaci n one products were included in the list of ten

rodenticides addressed in this document. The focus of this decision was:

1) T o minimize children’s exposure to rodenticide products used in homes by requiring that all rodenticide bait products marketed to general and residential consumers be sold only with bait stations, with loose bait ( e.g. , pellets and meal) as a prohibited bait

form. 2) To reduce wildlife exposures and ecological risks, by requiring sale and distribution limits intended to prevent general consumers from purchasing residential use bait products containing four of the ten rodenticides that pose the greatest risk to wildlife (the second generation anticoagulants

– brodifacoum, bromadiol one, difenacoum, and difethialone). Moreover, bait stations will be required for all outdoor, above

- ground uses of these second generation anticoagulants.

EPA update d its previous risk assessment findings conducted in support of the May 2008 RMD through t he application of additional effects and exposure data, use of additional exposure modeling, and quantitative risk assessment techniques for the four rodenticides subject to the Notice of Intent to Cancel ( NOIC ) (brodifacoum, difethialone, warfarin and bro methalin) and for

two rodenticides that are likely alternatives ( i.e., active ingredients included in products with

RMD

- compliant registrations for commensal rodent control, specifically, chlorophacinone and diphacinone (067701) ; bromethalin has both compliant and non

- compliant registrations). To support the NOIC, EPA conducted an extensive assessment of the potential for primary and secondary effects of the rodenticides under evaluation. This work was brought before the Science Advisory Panel (SAP) in 2011 for review; meeting materials are available under docket number

EPA

- HQ

- OPP

- 2011

- 0718

.



## 4.3 New Use Assessments

The two most recent Section 3 New Use assessment s were:

### 12

 proposed use of diphacinone (067701) on black

- tailed prairie dogs (BTPD, Cynomys

ludovicianus ) (DP Barcode D403356, completed in 2012 )

 p roposed label amendment for diphacinone (067701) to add California ground squirrel (CGS, Spermophilus beechyi ) as a target species and to expand the treatme nt area ( both geographically and use sites ) for voles (DP Barcode D426928, completed in 2015)

The se risk assessment s suggested that diphacinone (067701) presents a risk to both endangered

and non

- endangered species of terrestrial animals, including mammals, birds, terrestrial

- phase amphibians, reptiles, and invertebrates. There was a potential for direct effects to listed terrestrial animals (vertebrates and invertebrates) through consumption of bait or prey that have eaten bait. Consequently, there is a potential concern for indirect effects upon the listed organisms due to decreased prey availability and habitat modification (for individuals that use the BTPD or CGS burrows). Risks to aquatic organisms, as well as to aquatic pl ants, were not expected for these proposed use s of diphacinone (067701) . Toxicity data are not available for aquatic or terrestrial plants; h owever, exposure , and thus risk, is expe cted to be low.

As stated in the Section 3 assessment s , the only available environmental fate data from studies for diphacinone (067701) are 1) physicochemical properties, 2) hydrolysis, 3) aerobic soil metabolism, and 4) aged column leaching. However, because of the specific results of studies and because the specific use and application rates for diphacinone, relative to established end

point toxicities, is low, EFED can satisfactorily evaluate/screen limits of potential environmental

concentrations an d ecological effects without additional environmental fate data. In these

assessment s for the pro posed use of diphacinone (067701) , EFED concluded that s tudies with a potential to add high value to the risk assessment were :

 Field Testing for Terrestrial Wi ldlife (850.2500)

,

 Acute Passerine Study (850.2100), and

 Avian Reproduction Study (850.2300), two species

.



## 4.4 Drinking water assessment

The previous assessments concluded that due to the application amounts and methods, and the low water solubility of di phacinone, the exposure of surface water or ground water is expected to be negligible . No drinking water assessment has been conducted

.



# 5 Environmental Fate and Transport

5.1 Transport and Mobility

Due to a relative low vapor pressure of approximately 1 x 10

- 8 

### Tor r and a Henry’s Law constant of approximately 2 x 10

- 10 

### atm

- m 3 

### /mole, the volatilization of diphacinone (067701) is not expected

to be a s ignificant route of dissipation . Since there is no accepted guideline study for adsorption, an empirical approac h to correlate the octanol to water partitioning ratio (Pow or Kow) and the soil organic matter to water sorption coefficient (Koc). The relationships (Sawhney 1989)

, assuming soil organic matter is typically about 58% carbon [ i.e. , organic carbon (oc) = organic

### 13

matter (om)/1.72)], are

log (Kom) = 0.904 log (Pow)

- 0.779 (n = 12, r

- squared = 0.989) log (Koc) = 0.904 log (Pow)

- 0.779 + log 1.72

Another empirical relationship given in a technical guidance document supported by the European Communit y (Directive 93/67/EEC) to calculate Koc from Pow is:

log Koc = 0.52 log (Pow) + 1.02

Log Pow for diphacinone (067701) is 4.27 (based on Kow of 20,000). Thus, from the first relationship, log Koc = 3.32 and Koc is roughly 2100; from the second, log Koc = 3.24 and Koc is roughly 1700. These similar Koc values indicate diphacinone (067701) to be slightly mobile.

When com bined with a low water solubility of 0.3 mg/L, the potential to contaminate ground

water is small.

There is no available bioconcentration study at this time. However, judging from the diphacinone (067701) octanol

- to

- water partitioning ratio (Kow) of appr oximately 20,000, there is a potential for bioconcentration.



## 5.2 Degradation

Diphacinone (067701) was stable against simple hydrolysis at pH 7 and 9. At pH 5

, hydrolysis proceeded with an extrapolated half

- life of approximately 44 days. Products of hydro lysis were not satisfactorily identified or quantified. However, since the apparent hydrolysis was appreciable only at acidic pH, the hydrolytic degradation will not be important in the natural pH

range.

Laboratory aerobic soil metabolism data are from a single sandy loam soil from North Dakota.

The mean half

- life of diphacinone (067701) in this soil was 30 days (average of 28 and 32 days) from studies done at two different radiolabeled positions. A major soil metabolite ( > 10% of dose) was diphenylg lycolic acid which peaked at a maximum of approximately 20

- 25% of the initial dose around one month after treatment. This metabolite then remained at a relatively constant concentration until the end of the 3.5 month study. This study also indicated that the major metabolite, diphenylglycolic acid, was somewhat resistant to further metabolism.

The chemical properties and environmental fate parameters are summarized in Table 3

.

### 14

Table 3

. Chemical Properties and Environmental Fate Parameters of Diphacinon e (067701)

Parameter Value Source

Selected Physical/Chemical Parameters

Molecular mass (molecular formula) 3 40.48 g/mol (C 23 

### H 16 

### O 3 

### ) calculated

Vapor pressure 1 x 10

- 8 

### torr DP268619, 2000

Aqueous solubility 0.3 mg/L http://extoxnet.orst.edu/pi ps/diphacin.htm



### Henry’s Law Constant 2 x10

- 10 

### atm

- m 3 

### /mol DP268619, 2000

O ctanol

- to

- water partition coefficient (K OW 

### ) 20,000 DP268619, 2000

Persistence in Water

Hydrolysis half

- life Stable in pH 7 and 9, 44 days (pH 5) MRID 43582401

Aqueous photolysis half

- life Stable DP268619, 2000

Persistence in Soil

Aero bic soil metabolism half

- life 28.3 days and 31.7 days MRID 42035001

– a single sandy loam soil

Mobility

Adsorption coefficients (K OC 

### ) 1700 mL/g 2100 mL/g based on the empirical approaches

(Note: DP214197, 1997, require to submit (1) hydrolysis, and (2) Leaching

- Adsorption/Desorption study).



## 5.3 Transformation Products

Chemical names and structures of diphacinone and its environmental transformation products are

listed in Table 4

. A major degradate of diphacinone is diphenylglycolic acid. Acute oral toxicity of diphenylglycolic acid to the mouse is LD 50 

### = 2000 mg/kg

- bw 1



### . This major degradate detected

in the aerob ic soil metabolism study, diphenylglycolic acid , comprised up to 25% of the applied material about a month after application. This degradate appears to be persistent, but its mobility is

unknown. Because diphacinone is formulated in pelleted bait or weat her

- resistant rodenticide products and primarily used in bait application, it is probable that contact of this degradate with

soil and water will be minimal. Furthermore, b ecause risk to the assessed species is expected to result from direct consumption of bait products or from consumption of prey which directly consumed the bait, the formation of degradation products in the soil and water is not of major

concern in this assessment. Risk from the diphenylglycolic acid degradate will not be quantified

in the risk assessment

.

1 See reference at: http://toxnet.nlm.nih.gov/cgi

- bin/sis/search2/r?dbs+hsdb:@term+@DOCNO+7709

### 15

Table 4

. Diphacinone and Its Environmental Transformation Products

Code Name/ Synonym Chemical Name Chemical Structure Study Type MRID Maximum

%AR (day) Final

%AR (study length)

PARENT

Diphacinone (067701) 2

- (diphenylacetyl)

indan

- 1,3

- dione

Diphacinone

sodium salt (067705) 2

- (diphenylacetyl)

indan

- 1,3

- dione

, sodium

TRANSFORMATION PRODUCTS

Diphenylglycolic

acid diphenylglycolic

acid Aerobic

soil 42035001 24.5

(30 days) 16.3

(105 days)

Carbon dioxide Carbon dioxide Aerobic

soil 42035001 37.3

(105 days) 37.3

(105 days)



# 6 Receptors

6.1 Toxicity Summary

Table 5 provides a summary of the taxonomic groups and the surrogate species tested to characterize the potential acute and chronic ecological effects of diphacinone

. All toxicity data were derived using diphacinone (067701); however, these data are bridged to di phacinone sodium salt (067705). In addition, the table provides a preliminary overview of the potential acute toxicity of diphacinone by providing the acute toxicity classifications. No ecotoxicity data

### 16

are available for any degradates of diphacinone

. All available toxicity data are summarized in Appendix B

.

Diphacinone is highly toxic to slightly toxic to birds on an acute oral basis, moderately toxic to birds on a subacute dietary exposure basis, and very highly toxic to mammals on an acute oral

exposure basis. Studies evaluating chronic toxicity of diphacinone to birds and mammals have not been submitted to the Agency. In addition, data on the toxicity of diphacinone to terrestrial invertebrates and terrestrial plants have not been submitted to the Agenc y.

Brooks et al. (1998) evaluated oral and dermal toxicity of diphacinone to Brown Tree Snakes ( Boiga irregularis)

. Acute oral exposure to diphacinone resulted in LD 50 

### s of 20.75 mg/kg

- bw with a slope of 4.23 (ethanol used as a carrier) and 32.21 mg/kg with a slope of 5.0 (propylene glycol used as a carrier). All snakes were observed for seven days; all mortalities occurred within 24 hrs of diphacinone administration. At necropsy, there was no evidence of hemorrhaging, suggesting diphacinone has an alt ernative mode of action in snakes. No mortalities occurred following dermal application of diphacinone.

Technical grade diphacinone is classified as moderately toxic to freshwater fish and invertebrates on an acute exposure basis. Acute estuarine/marine fish and invertebrate data as well as chronic exposure effect data to diphacinone for fish and invertebrates have not been submitted to the Agency. In addition, no toxicity data for aquatic plants were submitted to the Agency.

Table 5

. Most Sensitive T est Species Evaluated for Assessing Potential Ecological Effects

of Diphacinone 1



### .

Taxonomic Group Study

Type Tested Species Toxicity Endpoint Acute Toxicity

Classification/

NOAEC most

sensitive endpoint(s) MRID and

Classification

Birds 2 Acute oral

(primary

bait consumer) Northern

bobwhite

Colinus virginianus LD 50 = 1630 mg a.i./kg

bw Slope = na Slightly toxic.

Mortalities occurred ≤5 days after gavage, observed 30 days 42245201

Acceptable

Acute oral (secondary consumer) American

kestrel ( Falco sparverius) LD 50 = 98.6 mg a.i./kg

bw Slope = 6.69 Highly toxic.

7

- day study;

mortalities

occurred 8

- 47 hrs after dosing Rattner et al.

2011
Supplemental/
Quantitative

Dietary Mallard duck

( Anas platyrhynchos ) LC 50 = 906 mg a.i./kg

diet Slope = 0.5 Moderately toxic.

25

- day test, most

mortalities from

3

- 8 days, all

mortalities less than 16 days 42408802

(Acceptable)

Chronic No data

Reptile Acute oral

(single dose) Brown tree

snake ( Boiga irregularis) LD 50 = 20.75 mg

a.i./kg

- bw Slope = 4.2 Highly toxic.

7

- day study;

mortalities

occurred within Brooks et al.

1998. Supplemental, quantitative.

### 17

Table 5

. Most Sensitive T est Species Evaluated for Assessing Potential Ecological Effects

of Diphacinone 1



### .

Taxonomic Group Study

Type Tested Species Toxicity Endpoint Acute Toxicity

Classification/

NOAEC most

sensitive endpoint(s) MRID and

Classification

24 hrs of dosing

Mammals Acute oral

(single dose) Laboratory Rat

(male), Rattus norvegicus LD 50 = 1.9 mg a.i./kg

bw Slope = na Very highly toxic.

14

- day study,

mortalities from days 2

- 9 05002272

supplemental

Dietary (5

- day exposure) Laboratory Rat LC 50 = 2.08 mg a.i./kg

diet Slope = 4.2 Very highly toxic.

Observed 14 days, mortalities days 4

- 12 Teeters 1981

(TNM 75) 4 (Supplemental)

Chronic No data

Terrestrial

invertebrates Acute

contact No data

Freshwater

fish 3 Acute Rainbow trout (Oncorhynchus mykiss) 96

- hr LC 50 = 2.6 mg

a.i./L moderately toxic 43249502 5 (Acceptable)

Chronic No data

Freshwater

invertebrates Acute Water flea ( Daphnia magna) 48

- hr EC 50 = 1.8 mg

a.i./L moderately toxic 42282201 (Acceptable)

Chronic No data

Estuarine/

marine fish Acute and

Chronic No data

Estuarine/

marine

invertebrates Acute and

Chronic No data

Terrestrial plants Seedling

emergence No data

Vegetative vigor No data

Aquatic plants and algae Vascular No data

Non

- vascular No data

1 Unless otherwise noted, toxicity data were derived using diphacinone (067701); however, these data are bridged to diphacinone sodium salt (067705).

2 Birds represent surrogates for terrestrial

- phase amphibians and reptiles.

3 Freshwater fish are used as surrogates for aquatic

- phase amphibians.

4 Teeters, W.R. (1981) Diphacinone technical: Toxicity to Laboratory Rat: Test No. 75. (U.S. Enviro nmental Protection Agency, Pesticides Regulation Div., Agricultural Research Center, Animal Biology Laboratory, unpublished report.)

5 Study was conducted using technical diphacinone sodium salt (067705); however, the LC 50 is reported as concentration of diphacinone (067701) in water.



## 6.2 Secondary Toxicity

Secondary toxicity was evaluated in the laboratory setting by exposing carnivorous birds and

mammals through the dietary route. Test animals were fed diphacinone in whole or ground

### 18

carcasses, which were usually those of rats or mice, or in fortified meat. Most prey animals were fed treated bait, although some were dosed orally. Mortality was included as a measurement endpoint in all studies. Some studies also repo rted signs of toxicosis ( e.g., bleeding, prolonged

blood

- coagulation time, abnormal behavior, or regurgitation) in surviving test animals. Although exposure scenarios, test species, and the number of test animals varied among the studies, collectively thes e studies provide useful information to characterize secondary hazards from

short

- term exposure. Though these types of secondary exposure studies provide information on the potential effects from diphacinone exposure that may occur under field conditions, it is often not possible to quantify the level of exposure (rodenticide residues in primary consumers or food consumption by secondary consumers) or the sensitivity of the exposed animals to the

rodenticide.

Nine percent mortality was recorded in th ree secondary bird exposure studies that in volved 34

individual birds from five species ( Table 6 ). Test species were barn owls, great horned owls,

saw

- whet owls (

Aegolius acadicus ), golden eagles, and American crows ( Corvus brachyrhynchos ). Thirteen (42%) of the survivors displayed some signs of toxicity. In three secondary mammal exposure studies, 19 (58%) of 33 test mammals died after feeding on rodents fed diphacinone, liver tissue from owls fed diphacinone, or fortified meat. Species affected

included m ink ( Mustela vison ), mongoose , ermine, deer mice, rats, and dogs ( Table 7 ).

### 19

Table 6 . Observed Effects of Diphacinone (067701) on Birds Consuming Contaminated Carcasses

Secondary species Prey offered to birds No. prey offered daily per bird No. days birds exposed No. birds

exposed No. birds

dead No. survivors

with signs of diphacinone toxicity a Reference

(MRID)

Great horned

owl Mice fed choice of

0.01% bait or

untreated food for 10 days 2 5 3 2 1 (ct) Mendenhall and

Pank 1980

MRID #

46750931

Saw

- whet owl Mice fed choice of

0.01% bait or

untreated food for 10 days 2 5 1 1 No survivors Mendenhall and

Pank 1980

MRID #

46750931

Barn owl Mice fed choice of

0.01% bait or

untreated food for 10 days Ad libitum 10 2 0 0 Mendenhall and

Pank 1980

MRID #

46750931

American

crow Rats f

ed 0.005% bait

until death 1

1

- 2 b 1

6 10

11 0

0 0

5 (eb/ct) Massey et al.

1997

Golden eagle Meat laced at 2.7 mg

a.i./kg 454 g 5

10 4

3 0

0 4 (eb/ct)

3 (eb/ct) c Savarie .et al.

1979

MRID#

00079312

a eb = external bleeding; ih = internal hematoma; bl = bleeding (unspecified); ct = increased blood coagulation time; nr = not reported

b offered 1 rat per crow for 5 days and 2 rats per crow on day 6

c general weakness of all eagles was observed after 5 da ys

### 20

Table 7 . Observed Effects of Diphacinone (067701) on Mammals Consuming Contaminated Carcasses

Secondary species Prey offered to

mammals No. prey offered

daily per

mammal No. days

mammals exposed No.

mammals exposed No.

mammals

dead No. survivors

with signs of diphacinone toxicity a Reference

(MRID)

Mink Nutria fed 0.01%

carrot bait for up to 10 days Ad libitum 5

- 18 3 3 no survivors Evans and W ard

1967 b

Mongoose Rats fed 0.005% bait

for 5 days 1 1

3

5

6

7

8

10 1

1

2

1

1

1

1 0

1

2

1

1

1

1 nr

no survivors

no survivors

no survivors

no survivors

no survivors

no survivors Pank and Hirata

1976

MRID# 2467 Ermine Deer mice fed 0.01%

bait for 10 days 2 5 2 1 nr

Striped skunk Deer mice fed 0.01%

bait for 10 days 2 5 5 0 nr

Deer mouse Liver from

diphacinone poisoned

owls 1 g daily 7 4 1 3 (ct)

Rat Meat containing 0.5

mg a.i./kg Ad libitum 6 8 4 nr Savarie et al

. 1979

Dog (domestic) Nutria fed 0.01%

carrot bait for up to 10 days Ad libitum 6

- 10 3 3 no survivors Evans and Ward

1967 b

a eb = external bleeding; ih = internal hematoma; bl = bleeding (unspecified); ct = increased blood coagulation time; nr = not reported

b Cited in US EPA (2004 b ) Potential Risks of Nine Rodenticides to Birds and Nontarget Mammals: a Comparative Approach

### Page 21 of 60 

## 6.3 Incident Database Review

A thorough review and analysis of available incident reports for all registered anticoagulant rodenticides was completed in 2013, and a summary of the 24 diphacin one wildlife incidents reported with a certainty of po ssible, probably, or highly probable is

included in Appendix D

. This means that, at a minimum, there was supporting evidence ( e.g ., hemorrhaging) and/or residue data to indicate that the wildlife involved in the incident was adversely affected by exposure to an anticoagulant rodenticide and/or an independent wildlife specialist, based on findings of a necropsy examination and toxicological analysis, identified an anticoagulant rodenticide as the cause of death in the incident report. The summary of incident reports will be updated at the time of the Registration Review.

The reported avian species include a granivorous pigeon and carnivore/scavenger birds that include the snowy owl, great horned owl, turkey vulture, bald eagle, red

- tailed hawk, and Cooper’s hawk. The reported mammalian species include herbivorous and granivorous deer, rabbits, squirrels, and kangaroo rat. Omnivorous mammals such as a raccoon and feral pig and carnivores including the San Joaquin kit fox, coyote, bobcat,

and mountain lion were also cited in the reported incidents. The types of species involved in the reported incidents indicate that non

- target species are likely being exposed via direct ingestion of the bait or through secondary exposure ( i.e ., ingesting a contaminated prey it em).

Although most of the reported wildlife incidents involve animals found dead, there are several rodenticide incidents that involve incapacitated animals (most of which died after being found). They demonstrate that animals exposed to rodenticides ma y be incapacitated in ways that would almost certainly make them more vulnerable to predators and accidental deaths ( e.g., car or window strikes). If an animal dies due to predation or an accident, their death may not necessarily be attributed to a pestic ide, even if it is a contributing factor.



# 7 Exposure Pathways of Concern

The environmental fate properties and use patterns of diphacinone indicate th at non

target consumption of bait, consumption of individuals that have consumed bait, and

runoff represent potential transport mechanisms of di phacinone to aquatic and terrestrial organisms.

Drinking water and inhalation exposure pathways were screened using the SIP (Screening Imbibition Program) and STIR (Screening Tool for Inhalation Risk) screen ing

methods SIP and STIR are described in detail at: http://www2.epa.gov/pesticide

science

- and

- assessing

- pesticide

- risks /models

- pesticide

- risk

- assessment#terrestrial

. The drinking water pathway was found not to be an exposure pathway of potential concern for

acute and chronic risks to mammals as well as chronic risks to birds due to low solubility

of di phacinone. The inhal ation exposure pathway was found not to be an exposure

### Page 22 of 60



### pathway of concern for birds due to the low volatility of di phacinone

. SIP and STIR results are presented in Appendix C

.



# 8 Analysis Plan

8.1 S tressors of Concern

8.1.1 Ecological Risk

Diphacinone sodium salt (067705) easily and quickly converts to diphacinone (067701) by hydrolysis in the environment. Therefore, all environmental fate and toxicity data for diphacinone (067701) will be bridged to diphacinone sodium salt (067705). Fate and toxicity data are not available for diphacinone sodium salt (067705). Collectively, these chemicals will be referred to as diphacinone, and one common risk assessment will be

conducted.

Diphacinone has two major degradates: diphenylglycolic acid and carbon dioxide. Acute

oral toxicity of diphenylglycolic acid to the mouse is LD 50 

### = 2000 mg/kg

- bw 2



### . For the

outdoor uses of diphacinone , it is formulated in pelleted bait or weather

- resistant rodenticide products, it is probable that contact of this degradate with soil and water wi ll be

minimal. Furthermore, b ecause risk is expected to result from direct consumption of bait products or from consumption of prey which directly consumed the bait, the formation of degradation products in the soil and water is not a major concern in thi s assessment. Risk

from the diphenylglycolic acid degradate was, therefore, not quantified.

8.1.2 Drinking Water

The previous assessments concluded that due to the application amounts and methods and low water solubility of diaphacinone, surface water or gro und water contamination with diphacinone is unlikely. No drinking water assessment will be needed.



## 8.2 Measures of Exposure

In this assessment, transport of di phacinone through runoff to water bodies is considered in deriving quantitative estimates of di phacinone. With a vapor pressure of 1.0 x 10

- 8 

### torr and a calculated Henry’s Law constant 2 x 10

- 10 

### atm∙m 3 

### ∙mol

- 1 

### for diphacinone (067701)

, volatilization and atmospheric transport are unlikely.

For this registration review, it will be assumed that terrestrial animals could be exposed to diphacinone through two pathways. Animals may directly consume bait (primary

2 See reference at: http://toxnet.nlm.nih.gov/cgi

- bin/sis/search2/r?dbs+hsdb:@term+@DOCNO+7709

### Page 23 of 60



### consumption), or animals may consume contaminated carcasses either killed or

scavenge d by the consumer (secondary consumption). Both approaches and the expected exposure levels are detailed below. It is important to note that these methods are different

from those typically used in EFED risk assessments.

8.2.1 Estimating Aquatic Exposure

Aquat ic exposure due to runoff will be estimated using the Tier 1 GENEEC model and input parameters provided in Table 8 . GENEEC is a metamodel of the Tier 2 models

PRZM and EXAMS and is hard

- wired to a single, high exposure scenario which is intended to be prot ective of aquatic environments for all crops on a national basis. While the specific scenario built into GENEEC is a 10 ha field draining into a 1 ha pond, 2 meters deep, with no outlet, this scenario is intended to serve as a surrogate for a wide variety of small vulnerable water bodies that occur near the top of watersheds. These include prairie potholes, swamps, bogs, and other wetlands, playa lakes, and zero and

first

- order streams.

Table 8. Diphacinone Input Values (GENEEC) for Aquatic Exposures

Parameter Value Comment Solubility 0.3 mg/L http://extoxnet.orst.edu/pips/diphacin.htm Hydrolysis Stable at pH 7 and 9 

### MRID 43582401
Photolysis in Water Stable 

### DP268619 (2000) Photodegradation on Soil Stable Conservation assumption

Aerobic Soil Degradation 90 days (half

- life) 30 days in single soil study ( 

### MRID

42035001)

– adjusted to 90 days (3X) for model input Aerobic Aquatic Degradation 180 days (half

- life) 2X aerobic soil value

K
oc 17 00 L/kg Based on empirical approach in Section

5.1. Incorporation Depth 0.0 inches All labels for broadcast application do not allow for incorporation. Application Rate 0.0136 lb ai/ac Highest labeled application rate appears on the SLN, CA78046: “Use a mechanical seed spreader calibrated to evenly spread 2 oz of bait to cover 40 to 50 square feet near active burrows or runways. Retreat every other day for 3 to 4 applications.” Most labels that permit broadcast application restrict the maximum single application rate to 10 lbs product/acre ( 0.0005 lbs a.i./ acre). Number of Apps. 4

Application Interval 2 days

### Page 24 of 60



### The GENEEC results based on the input value s of Table 8 are presented below:

The estimated environmental concentrations (EECs) are 0.731 μg/L, 0.685 μg/L, and 0.607 μg/L, respectively for the peak concentration, 21

- day average concentration, and

60

- day average concentration. Considering the low water solubility of 0.3 mg/L, these EECs are only in the ra nge of about 0.2% of solubility; therefore

, the likelihood of aquatic impacts from the exposure viewpoint is insignificant

.

8.2.2 Estimating Primary Terrestrial Exposure

EFED’s exposure assessment for the rodenticides differs from that for most other pesticides . For a rodenticide, the bait itself is the potential fo od item of concern. Thus, the amount of active ingredient in the formulated bait is used as an estimated environmental concentration ( EEC )

. This information is used to estimate the amount of grain bait that birds and mammals of various sizes need to consu me to obtain a dose expected to be lethal to 50% of the individuals in the population ( i.e. , LD 50 

### dose).

Estimates of food

- ingestion rates (g dry matter per day) are determined from established allometric equations presented in the Wildlife Exposure Factor s Handbook ( US EPA 1993). The concentration of di phacinone in grain bait is also used to estimate dietary exposure (mg a

. i

. per kg in bait).



## 8.2.2.1 Expected Diphacinone Accumulation through a Single Feeding

on Bait

Exposure through bait consumption will be calculated using two methodologies. For the first method, diphacinone exposure is calculated as mg a.i./kg

- bwt, where kg

- bwt is the kilograms of the consuming individual for three standard weight classes of passeri forms and rodents. Exposure (food dry weight consumption) estimates were derived using allometric equations from USEPA (1993). The allometric equations for passeriform birds RUN No. 1 FOR Diphacinone ON Rodent * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE NO

- SPRAY INCORP
ONE(MULT) INTERVAL Koc (PPB ) (%DRIFT) (FT) (IN)

-------------------------------------------------------------------- 0.014( 0.055) 4 2 1700.0 300.0 GRANUL( 0.0) 0.0 0. 0

FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (POND) (POND

- EFF) (POND ) (POND)

-------------------------------------------------------------------- 90.00 2 0.00 0.00

- 0.00 180.00 180.00

GENERIC EECs (IN NANOGRAMS/LITER (PPTr)) Version 2.0 Aug 1, 2001

-------------------------------------------------------------------- PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY

GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC

------------------------------------------ -------------------------- 731.10 723.89 684.96 606.70 555.46

### Page 25 of 60



### and rodent mammals were used as these would best approximate those individuals wit h high potential for consuming grain and they would give the most conservative exposure estimates. Food dry weight was converted to wet weight assuming the bait contained 10% water, similar to the assumption that seeds for wildlife consumption contain 10% water (USEPA 1993). Formulas for calculation of dose estimates are provided in Table 9 , and diphacinone exposure estimates (on a dose basis) are provided in Table 10

.

Table 9 Formulas for Calculation of Daily Di phacinone Intake based on Consumption of

Ba it.

Passeriform bird food intake (g, dry weight ): FI (g dry

- wt/day) = 0.398 * Wt(g) 0.850



### Rodent mammal food intake (g, dry weight ): FI (g dry

- wt/day) = 0.621 * Wt(g) 0.564



### Food intake (g, wet weight ): FI (g wet

- wt/day) = FI (g dry

- wt/day) / 0.90

Di phacinone intake (mg a.i./kg

- bwt/day) = FI (g wet

- wt/day) * mg a.i./kg

- bait / Wt(g)

Where: Wt(g) = weight (in grams) of the bird or mammal consumer

mg a.i./kg

- bait = 50 or 100 depending on diphacinone concentration in bait

Table 10. Expected Daily Diphacinone Intake for Default Bird and Mammal Weights based on Consumption of Bait.

Weight (g) Food intake

(g dry

wt/day) Food intake

(g wet

wt/day) Di phacinone intake (mg a.i./kg

- bwt/day)

Bait concentration = 50 mg a.i./kg

- bait Bait concentration = 100 mg a.i./kg

- bait

Passeriform

Birds * 20 5.1 5.6 14.1 28.2

100 19.9 22.2 11.1 22.2

1000 141.2 156.9 7.8 15.6

Rodent

Mammals 15 2.9 3.2 10.6 21.2

35 4.6 5.1 7.3 14.6

1000 30.6 34.0 1.7 3.4
*surrogate for reptiles and terrestrial

- phase amphibians



## 8.2.2.2 Expected Diphacinone Accumulation through Multiple Feedings

on Bait

Available data on the retention times of diphacinone in animal tissues are provided in

Table 11 . Yu et al. (1982) studied the metabolism and disposition of diphacinone in rats and mice. Rats given a single oral dose of radiolabeled diphacinone at either 0.18 or 0.4 mg a.i./kg, about 70% of the dose was eliminated in feces and 10% in urine within 8

### Page 26 of 60



### days, wherea s about 20% of the dose was retained in body tissues. Mice given a single dose of 0.6 mg a.i./kg eliminated most dipha cinone within 4 days, and only 30 % was retained in body tissues. In another study, cattle that received a single injection of 1 mg a.i./kg had almost constant residue concentrations in liver and kidney at 30, 60, and 90 days a fter dosing (Bullard et al. 1976 ). Crowell et al. (2013) evaluated heptatic half

- life of diphacinone in red deer, pigs, and cattle. The diphacinone half

- life in red de er and pigs (6 and 12.4 days, respectively) was similar to much of the earlier data. The estimated

half

- life of diphacinone in cattle livers was much longer (similar to the cattle data obtained by Bullard et al. (1976 ). These data demonstrate that there is high species variation in elimination rates of diphacinone in mammalian livers.

Diaz and Whitacre (1976) orally dosed rats with diphacinone (0.32 mg a.i./kg/day) for

one or two days. Rats dosed for one day were sacrificed at 48 hours

, and rats dosed for

two consecutive days were sacrificed 72 hours after the second dose. In rats dosed once and sacrificed after 48 hours, about 5% of the dose was excreted in feces and urine, 61%

was retained in body tissues, and 34% was not recovered

. Intestines, liver, an d hide/tail had the highest percentages of diphacinone with 22, 19, and 11%, respectively. In rats

dosed twice , 45% of the total dose was excreted, 25% was retained in body tissues , and

30% was not recovered. The body tissues retaining the most diphacinone at 96 hours

w ere the hide/ tail, liver, intestine, and blood (percentage of diphacinone ranged from 4 to 6.5%)

.

Table 11 . Retention of Diphacinone in Liver
Species Dose (mg a.i./kg) # doses Liver retention (days) Reference (MRID)

Pig 12.5 (oral) 3 or 5 Half

- life = 5.43 days Fisher 2006

Pig 1.5 (oral) 1 Half

- life = 12.4 days Crowell et al. 2013

Rat 1.5 (oral) 1 Half

- life = 3 days Fisher et al. 2003 (48190801)

Rat 0.18 or 0.4 (oral) 1 20% of dose in body tissues at 8 days, highest concentrations in liver (1.4 and 1.0 mg a.i./kg

- liver, respectively ) Yu et al. 1982

Mouse 0.6 (oral) 1 30% of dose in body tissues at 4 days, highest concentrations in liver (0.6 mg/kg

- liver) Yu et al. 1982

Cattle 1.0 (injection) 1 Half

- life > 90 days Bullard et al. 1976

Cattle 1.5 (oral) 1 Trial 1 : Initial (day 0 to 30): 9.4 days: Terminal (day 30 onwards): 25.2 days

Trial 2 : Initial(day 0 to 30): 4.1 days; Terminal (day 30 onwards): 35.4 days Crowell et al. 2013

Red deer 1.5 (oral) 1 Half

- life = 6 days Crowell et al. 2013



### As indicated previously, diphacinone typically cause s mortality several days after ingestion , which m ay allow target animals consume bait for several days before dying. This can lead to doses that far exceed the lethal dose. A compound that accumulates in body tissues may pose greater risk to primary and secondary consumers, especially if repeated sublethal exposure results in the accumulati on of a lethal dose or if additional

### Page 27 of 60



### exposures occur before the lethal dose has taken its effect ( i.e., leading to a dose that is beyond what is sufficient to cause mortality).

Cumulative rodenticide doses for animals consuming bait for six consecutive d ays were also calculated using formulae in Table 12

. This analysis will assume that 100% of the daily diet of the animals is represented by the rodenticide bait and that they eliminate the dip hacinone with a half

- life of 12.4 days based on the highest definitive liver half

- life value ( Table 11 )

. In the formula, the variable “C” represents the concentration of the pesticide in the bait. The elimination rate constant (k) was calculated using the estimated diphacinone half

- life ( t 1/2 

### = 12.4 days), and f ood intake (FI) was calculated according to the allometric equation for each taxonomic group ( Table 12 ). The resulting cumulative body burden concentrations of diphacinone are presented in Table 13

.

Table 12. Formulas for Calculat ion of Di phacinone Body Burden based on Consumption of Bait for Six Consecutive Days

.

Table 13

. Calculated d iphacinone body burden in avian and mammalian consumers of bait after six days of exposure

Body weight (g) Bait concentration = 50 mg a.i./kg

- bait Bait concentration = 100 mg a.i./kg

- bait

Passerine Generic Bird Passerine Generic Bird

20 73.7 66.1 175.4 132.2

100 57.9 37.7 115.8 75.4

1000 41.0 16.9 82.0 33.8

Rodent Generic Mammal Rodent Generic Mammal

15 55.3 42.1 110.6 84.2

35 38.2 36.2 76.4 72.4

1000 8.9 19.9 17.8 39.8



## 8.2.2.3 Expected Diphacinone Exposure based on Bait Concentration

The second exposure method for primary consumption of bait results in a diet concentration of 50 or 100 mg a.i./kg

- bait (concentrations of diphacinone as packaged in bait).

8.2.3 Estimating Secondary Terrestrial Exposure

Secondary exposure analysis (from consumption of contaminated individuals ) require s consideration of residues in tissues of target and non

- target organisms that are commonly

consum ed by predators and scavengers

. Moreover, it is important to know how long the residue persists in body tissues. Residue concentrations for non

- target animals fed chlorophacinone were submitted by the registrant and are a vailable in open literature. Design and methodology vary among studies, adding unknown variability to the results and analysis. Pending development of additional methods and testing requirements for

### Page 28 of 60



### such studies, these tests provide the best data available.

The determination of diphacinone intake for individuals consuming diphacinone poisoned animals or carcasses is calculated in a manner similar to the approach for individuals consuming bait ( Secti on 3. 3 .1 ). Empirical residue data will be used instead of bait concentration of diphacinone ( Table 14 ). Diphacinone body burdens in deceased field and laboratory studies were determined in mammals, after exposure to diphacinone

bait. Data from four studie s were available in which deceased ground squirrels were collected from treated fields and analyzed for diphacinone residues. For all studies, it was assumed the concentrations were reported using wet weights of the mammals . Mean concentrations ranged fro m 0.9 to 1.4 mg a.i./kg

- bw , with reported individual values ranging from 0.48 to 3.4 mg a.i./kg

- bw. Field collected data are subject to a number of uncertainties including, but not limited to:

 possible partial decomposition of bodies in field,

 collectio n may miss carcasses with highest body burdens, and

 collection may miss individuals that were rapidly predated, died off site, or died underground.

Because of the lack of data on diphacinone residues in birds, amphibians

, and reptiles, it

was assumed the mammal body burden data would be relevant for all the evaluated taxonomic groups. Due to the uncertainties regarding adequate sampling to capture the full distribution of carcass residue values, the maximum reported individual value, 3.4 mg a.i./kg

- carcass , will be used for this assessment.

Table 14

. Measured Residue Levels of Diphacinone in Field Exposed California Ground Squirrels

Mg a.i./kg

bait Sample

size Days exposed Mean whole

- carcass residue in mg a.i /kg

carcass (range) Reference

50 10 unknown 1.4 (0.6

- 3.4) Baroch 1994a

MRID# 43534601

50 7 unknown 0.9 (0.48

- 1.89) Baroch 1994b

MRID# 43534602

100 10 unknown 1.4 (0.6

- 2.6) Baroch 1994a

MRID# 43534601

50 and 100 a 76 unknown 0.98 Goodall et al. 2002

MRID# 46117303

a the study did not allow for distinguishing among squirrels exposed to 50 mg a.i./kg and 100 mg a.i./kg b 

### ai ts



### Diphacinone exposure through carcass consumption is calculated as mg a.i./kg

- bwt, where kg

- bwt is the kilograms of the consuming individual for three weight classes of birds and mammals. For this analysis, bird weight classes of 10 0, 1000, and 5 000 g

indiv iduals and mammal weight classes of 50, 1000, and 3000 g individuals were used to better represent the larger size of carnivores and scavengers relative to the full range of bird and mammal weights. The measured maximum body burden in the prey was then

use d to estimate rodenticide exposure in the secondary consumer using the general food intake allometric equations described in Section 3.1 above. Secondary consumers were

### Page 29 of 60



### assumed to be mammals weighing 50g, 1000g, or 3000g, or birds weighing 100g, 1000g,

or 5000g. For example, American kestrels range from 100

- 150g, red

- tailed hawks range

from 900

- 1000g and bald eagles range from 4000

- 5000g (Dunning 1984). Exposure (food dry weight consumption) estimates were derived using the generic bird and

mammal allometr ic equations from (EPA 1993). Food dry weight was converted to wet weight assuming the consumed prey/carcass contained 68% water (USEPA 1993). Formulas for calculation of dose estimates are provided in Table 15 , and diphacinone exposure estimates (on a dos e basis) are provided in Table 16 . Secondary consumers that were snakes were assumed to consume prey equivalent to their body weight in a single feeding; however, feedings would not occur on a daily basis (King, 2002).

Table 15. Formulas for Calculation of Daily Di phacinone Intake for Birds and

Mammals based on Consumption of Carcasses

.

B ird food intake (g, dry weight ): FI (g dry

- wt/day ) = 0. 648 * Wt(g) 0. 651



### Mammal food intake (g, dry weight ): FI (g dry

- wt/day) = 0. 235 * Wt(g) 0. 822



### Food intake (g, wet weight ): FI (g wet

- wt/day) = FI (g dry

- wt/day) / 0.32

Di phacinone intake (mg a.i./kg

- bwt/day) = FI (g wet

- wt/day) * 3.4 mg a.i./kg

- carcass / Wt(g)

Where: Wt(g) = weight (in grams) of the bird or mammal consumer

Table 16. Expected Daily Dip hacinone Intakes for Carnivorous Bird s, Snakes, and

Mammal s based on Consumption of Contaminated Carcasses

Weight (g) Food intake

(g dry

- wt/day) Food intake

(g wet

- wt/day) Diph acinone intake (mg a.i./kg

- bwt/day) 1

Birds * 100 13.0 40.6 1.38

1000 58.2 181.7 0.62

5 000 165.8 518.1 0.35

Snake** 50 16 50 3.4

250 80 250 3.4

500 160 500 3.4

Mammals 50 5.9 18.3 1.24

1000 68.7 214.7 0.73

3000 169.5 529.8 0.60 *surrogate for reptiles and terrestrial

- phase amphibians **Snakes are capable of eating the equivalent of their body weight in one meal; however, they will not consume that quantity of food on a daily basis.

1 See Table 15 for derivation.



### The second exposure method for consumption of contaminated carcasses results in a

carcass conce ntration of 3.4 mg a.i./kg

- carcass (maximum measured concentration of diphacinone in carcasses).

### Page 30 of 60 

### 8.2.4 Estimating Additional Environmental Exposures

Screening level calculations suggest that the drinking water pathway and inhalation pathways will not pose significant risks to birds and mammals ( Appendix C ). If additional information indicates there may be concerns, these pathways will be re

evaluated at the time of the risk assessment.

No monitoring data in surface water, in groundwater or in air were found from the USGS NAWQA program ( http://water.usgs.gov/nawqa ), the California Department of Pesticide Regulation CDPR ( http://www.cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm ) or from the USEPA STORET program. Water mon itoring programs such as these generally monitor for agricultural pesticides and typically do not include analysis for rodenticide s such as diphacinone. 

### If water monitoring data are identified at the time the risk assessment is

conducted , these data will b e used for additional exposure characterization.



## 8.3 Measures of Effect

Toxicity data presented in Section 6 of this problem formulation will be used to calculate risk quotients. Any additional information submitted by the registrant or found in the open literature prior to conduct of the risk assessment will also be considered. The open literature studies are identified using EPA’s ECOTOXicology database ( ECOTOX) (USEPA, 2007 c ), which employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data can also provide insight into the direct and indirect effects of pesticides on biotic

commun ities from loss of species that are sensitive to the chemicals and from changes in

structure and functional characteristics of the affected communities.



# 9 Endangered Species Assessment

Consistent with the Agency’s responsibility under the Endangered Specie s Act (ESA), the Agency will evaluate risks to federally threatened and/or endangered (listed) species from registered uses of pesticides in registration review . The process for evaluating potential risks to listed species is further described at http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm

.



# 10 Endocrine Disruptor Screening Program

Di phacinone was not included in the first group or the second group of chemicals issue d an order to conduct Tier 1 EDSP testing. For additional information the EDSP program,

visit http://www2.epa.gov/endocrine

- disruption

.

### Page 31 of 60



# 11 Preliminary Identification of Data Gaps

11.1 Fate

The environmental fate data base for diphacinone is not complete ( Table 1 7 ) . However,

due to the low water solubility o f diphacinone (0.3 mg/L) and the relatively low aquatic toxicity, a data gap was not identified as these data are not necessary for risk assessment

at this time.

Table 1 7. Availab le environmental fate data for diphacinone and remaining data gaps.

158

Guideline (OPPTS) Description MRI D Classification Are data

needed for risk

assessment? C omments

835.1240 (163

- 1) Adsorption/Desorption MRID 43 582402 supplemental no

Data have not been

submitted to fulfill this guideline. A data gap was

not identified as these data are not necessary for risk

assessment at this time. 835.2120 (161

- 1) Hydrolysis MRID 43582401 supplemental no

835.2240 (161

- 2) Photodegradation in water None NA no

835.2410 (161

- 3) Photodegradation on soil None NA no

835.4100 (162

- 1) Aerobic soil metabolism MRID 42035001 acceptable no

835.4200 (162

- 2) Anaerobic soil metabolism None NA no

835.43 00 (162

- 4 ) A erobic Aquatic

Metabolism None NA no

835.4400 (162

- 3) Anaerobic Aquatic

Metabolism None NA no

835.6100 (164

- 1) Terrestrial Field

Dissipation None NA no

850.1730 (165

- 4) Fish Bioconcentration

Factor None NA no



## 11.2 Effects

Tables 1 8 and 1 9 identify ecological effects studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not further data are needed in order to support risk assessment.

Inadequate data are available to further characterize the differential toxicity among bird species. In addition, there is evidence of different or multiple modes

- of

- action of diphacinone in different taxa. These differences were evidenced by the large variation in

the LD 50 

### between the bobwhite qu ail and the American kestrel and by the high mortality rates in the brown tree snake when no hemorrhaging was present upon necropsy ( Section

4.1 ). Additional toxicity data on a wider range of species or data exploring mode

- of

action would be beneficial to better understand the natural variation and to improve

### Page 32 of 60



### confidence in the assessment of risk to non

- target species.

No data are available to assess the effects of long

- term, low

- dose exposure of diphacinone on avian reproduction (OC S PP 850.2300) or surviv al. Avian reproduction data are available for another registered indandione anticoagulant rodenticide, chlorophacinone. Mallard ducks exposed to dietary chlorophacinone for five days had an

LC 50 

### = 172 mg/kg

- diet (MRID 41513103); however, nine of 16 (56%) a dult females died exhibiting symptoms of anticoagulant poisoning during the avian reproduction study eating a diet containing only 0.96 mg a.i./kg

- diet (MRID 489904002). EFED

recommends that additional data on effects of long

- term low

- dose exposure of diph acinone to birds through extended exposure dietary studies and avian reproduction

studies be requested

.

No data for diphacinone are available to assess the effects of long

- term, low

- dose exposure on mammalian reproduction

. Guidelines that would address this data gap are

the Prenatal Developmental Toxicity Study (870.3700) or Reproduction and Fertility Effects Study (870.3800) . Neither of these studied have been submitted to the Agency for diphacinone. Given the observed effects in the reproductive studie s reviewed for avian effects of chlorophacinone (bobwhite quail and mallards , discussed above ) and mammalian effects of chlorophacinone (laboratory rat, MRID 43349501, and New Zealand white rabbit, MRID 43570801) , the Agency is requesting data to evaluate reproductive effects of low doses of diphacinone on mammals. These data are important to determine exposure levels of diphacinone that would affect non

- target mammals.

No data are available to assess of the tox icity of diphacinone to terrestrial invertebrates. EFED does not have concerns for diphacinone exposure to insect pollinators such as bees and butterflies, as expected exposures would be low. Diphacinone is not applied as a

spray and is not expected to be systemic ; therefore, expected exposure on plants, including flowers, would be low. Insect p ollinators would not be expected to feed on live animals or carcasses that may have been contaminated with diphacinone. Diphacinone exposure to terrestrial inverteb rates may occur if individuals feed on the bait, feed on live

animals contaminated with diphacinone residues, or feed on carcasses with diphacinone residues. No terrestrial invertebrate incidents have been reported for diphacinone.

The earthworm LC 50 

### val ues for bromadiolone , a second generation rodenticide, at 24 h

and 48 h were 145.70 μ g/cm 2 

### and 25.03 μ g/cm 2 

### , respectively , and at 14 d and 28 d were 449.958 mg/kg

- soil and 105.593 mg/kg

- soil , respectively (Liu et al. 2015). Incidences of

terrestrial invert ebrates consuming bait containing an anti

- coagulant rodenticide and subsequently excreting it have been documented (Fisher et al. 2007; Hernandez

- Moreno

et al. 2013). Toxicity of diphacinone to terrestrial invertebrates is unknown; however,

there is eviden ce to suggest that toxicity may occur and that the exposure pathway for secondary exposure is complete. EFED is not requesting the full suite of pollinator protection studies as outlined in recent guidance ( http://www2.epa.gov/pollinator

protection/pollinator

- risk

- assessment

- guidance ). However , EFED does request an earthworm toxicity study for diphacinone and any addit ional existing data that demonstrate toxicity, or lack of toxicity, to diphacinone for terrestrial invertebrates.

### Page 33 of 60



### EFED does not recommend requesting terrestrial plant, aquatic plant, chronic fish, or chronic aquatic invertebrate toxicity data at this ti me as these data would not be expected to change the conclusions of this risk assessment. There remains uncertainty in the level of risk for each of these taxonomic groups given the missing data; however, the expected exposures will be relatively low:

 Terr estrial plants

- No data are available to assess of the toxicity of diphacinone to terrestrial plants; however, exposure to plants is also expected to be low since there is no spray application and the material is applied as a formulated bait or a

treated grain. Diphacinone binds strongly to organic material ( i.e. , the formulated bait or grain) and little is expected to be available for runoff or leaching. No plant incidents have been reported for diphacinone.

 Aquatic plants

– No data are available to asses s the toxicity of diphacinone to aquatic plants; however, aquatic exposure is also expected to be low since there is no spray application and the material is applied as a formulated bait or a treated grain. Diphacinone binds strongly to organic material ( i .e. , the formulated bait or grain) and little is expected to be available for runoff or leaching. No aquatic incidents have been reported for diphacinone.

 Chronic fish and aquatic invertebrates

– No data are available to assess the chronic toxicity of diph acinone to fish and aquatic invertebrates; however, aquatic exposure is expected to be low since there is no spray application and the material is applied as a formulated bait or a treated grain. Diphacinone is moderately acutely toxic to fish and inverteb rates, and chronic effects would not be unexpected. However, diphacinone binds strongly to organic material ( i.e. , the formulated bait or grain) and little is expected to be available for runoff or leaching for the current uses . No aquatic incidents have b een reported for diphacinone.

Table 1 8. Available ecological effects data for terrestrial organisms exposed to diphacino ne and remaining data gaps.

OCSPP

Guideline Data Requirement Submitted Studies (MRID) Study

Classification Are data

needed for

risk

assessment? Current Additional Data

Need

850.2100 Avian oral toxicity 42245201 acceptable Yes Data are requested for a vian acute oral with passerine Rattner et al

2010 supplemental

00 128411 supplemental

Rattner et al

2011 supplemental

850.2200 Avian dietary toxicity 42408801 acceptable No

--

42408802 acceptable

850.2300 Avian reproduction (None) (N/A) Yes Data are requested for avian reproduction toxicity testing for two species.

### Page 34 of 60



### Table 1 8. Available ecological effects data for terrestrial organisms exposed to diphacino ne and remaining data gaps.

OCSPP

Guideline Data Requirement Submitted Studies (MRID) Study

Classification Are data

needed for

risk

assessment? Current Additional Data

Need

Non

- guideline Avian inhalation (None) (N/A) No Data have not been

submitted to fulfill this guideline. A data gap was

not identified as these data are not necessary for risk

assessment at this time.

850.3020 Honey bee acute contact

toxicity (None) (N/A) No Data are requested to assess

risk to terrestrial invertebrates. Registrant may submit toxicity data for other

terrestrial invertebrate species to address this data

gap.

850.3030 Honey bee residue on

foliage (None) (N/A) No Data have no t been

submitted to fulfill these guideline s. D ata gap s were not identified as these data are not necessary for risk

assessment at this time. OECD TG

213 Acute oral toxicity to

adult honey bees (None) (N/A) No

OECD TG

237 Acute oral toxicity to

larval honey bees (None) (N/A) No

Non

- guideline Chronic oral toxicity to

adult honey bees (None) (N/A) No

Non

- guideline Chronic oral toxicity to

larval honey bees (None) (N/A) No

Non

- guideline Field trial of residues in

pollen and nectar (None) (N/A) No

OECD

Guidance 75 Semi

- field testing for

pollinator (None) (N/A) No

850.3040 Field testing for

pollinator (None) (N/A) No

850.3100 Earthworm Subchronic

Toxicity Test (None) (N/A) Yes Data are requested for earthworm toxicity.

850.4100 Seedling Emergence and

Seedling Growth (None) (N/A) No Data have not been

submitted to fulfill this guideline. A data gap was

not identified as these data are not necessary for risk

assessment at this time. 850.4150 Vegetative Vigor (None) (N/A) No

### Page 35 of 60



# 12 References

Open Literature

Brooks, J.E., Savarie, P.J. and J.J. Johnston. 1998. The oral and dermal toxicity of selected chemicals to Brown Tree snakes ( Boiga irregularis ). Wildlife Research 25:427

- 435.

Bullard, R.W., R.D. Thompson, G. Holguin. 1976. Diphenadione residues in tissues of cattle. Journal of Agricultural and Food Chemistry. 24:261

- 263.

Cox , P. and R.H. Smith. 1992. Rodenticide ecotoxicology : pre

- lethal effects of anticoagulants on rat

behavior. Proc. Vertebr. Pest Conf. 15:165

- 170. 

### Table 1 9. Available ecological effects data for aquatic organisms exposed to di phacinone and remaining data gaps.

OCSPP

Guideline Data

Requirement Submitted

Studies (MRID) Study

Classifications Are data

needed to

conduct risk

assessment? Current Additional Data Need

850.1010 Freshwater

invertebrate acute toxicity 42282201 * Currently under

re

- evaluation No

--

850.1025

850.1035

850.1045

850.1055 Saltwater

invertebrate acute toxicity (None) (N/A) No Data have not been submitted to fulfill this guideline. A data gap

was not identified as these data are not necessary for risk assessment

at this time.

850.1075 Freshwater fish

acute toxicity 43249501 * * Acceptable No

--

43249502 * * Acceptable

850.1075 Saltwater fish

acute toxicity (None) (N/A) No Data have not been submitted to fulfill this guideline. A data gap

was not identified as these data are not necessary for risk assessment

at this time. 850.1300 Freshwater

invertebrate life cycle (None) (N/A) No

850.1350 Saltwater

invertebrates life cycle (None) (N/A) No

850.1400 Freshwater fish

early

- life stage (None) (N/A) No

850.1400 Saltwater fish

early

- life stage (None) (N/A) No

850.1500 Fish life cycle (None) (N/A) No

850.4400 Aquatic plant

Toxicity Test using Lemna spp. (None) (N/A) No

850.4500 Algal toxicity (None) (N/A) No

850.4550 Cyanobacteria (None) (N/A) No

* Study being re

- evaluated and may be re

- classified as precipitate was observed in all test concentrations

** S tudies conducted using diphacinone sodium salt (067705); toxicity values reported as diphacinone (067701)

### Page 36 of 60

Crowell, M, C Eason, S Hix, K Broome, A Fairweather, E Moltchanova, J Ross and E Murphy. 2013. First generation anticoagulant rodenticide persistence in large ma mmals and implications for wildlife management. New Zealand Journal of Zoology, http://dx.doi.org/10.1080/03014223.2012.746234

Diaz, L.I. and D.M. Whitacre. 1976. Excretion and retention of 14 C

- diphacinone in rats. Unpubl. report, submitted by Velsicol Chemical Corporation. 8 pp. (MRID: 106901)

Dunning

, J. B.

, Jr

. 1984

. Body weights of 686 species of North American birds

. Monograph Number 1

. Western Bird Banding Association , Cave Creek, Arizona, USA

Fisher P 2006. Persistence of residual diphacinone concentrations in pig tissues following sublethal exposure. DOC Research & Development Series 249. Wellington, New Zealand, DOC. 19 p.

Fisher P, O’Connor C, Wright G, Eason CT 2003. Persistence of four anticoagulant rodenticides in the livers of laboratory rats. DOC Science Internal Series 139. Wellington, New Zealand, DOC. 19 p. MRID#

48190801

Fisher, P., Spurr, E., Ogilvie, S., and Eas on, C. 2007. Bait consumption and residual concentrations of diphacinone in the Wellington tree weta ( Hemideina crassidens ) (Orthoptera: Anostostomatidae). New Zealand Journal of Ecology 31(1): 104

- 110.

Hernandez

- Moreno, D., de la Casa

- Resino, I., Lopez

- Beceiro, A., Fidalgo, L., Soler, F., Perez

- Lopez , M.

2013. Secondary poisoning of non

- target animals in an Ornithological Zoo in Galicia (NW Spain) with anticoagulant rodenticides: a case report. Veterinarni Medicina, 58, 2013: (10): 553

– 559.

King, R.B. 2 002. Predicted and observed maximum prey size

– snake size allometry. Functional Ecology

16: 766

– 772.

Massey, G., L. Valutis, and J. Marzluff. 1997. Secondary poisoning effects of diphacinone on Hawaiian crows: a study using American crows as surrogates. Unpubl. report, U. S. Fish and Wildlife Service, Pacific Islands Office. 12 pp.

Mendenhall, V.M. and L.F. Pank. 1980. Secondary poisoning of owls by anticoagulant rodenticides. Wildl.

Soc. Bull. 8:311

- 315. MRID#s 46750931, 40077202, 00094694

Rattner, BA , KE Horak, SE Warner, DD Day, CU Meteyer, SF Volker, JD Eisemann, JJ Johnson. 2011. Acute toxicity, histopathology, and coagulopathy in American kestrels ( Falco sparverius ) following administration of the rodenticide diphacinone. Environmental Toxicology and Chemistry, Vol. 30, No. 5, pp. 1213

– 1222.

Sawhney, B. L. and Brown, K., Editors. 1989. Reactions and Movement of Organic Chemicals in Soils. SSSA Special Publication Number 22. Soil Science Society of America, Inc. Madison, WI.

Savarie, P.J. and R.K. LaVoie. 1979. Secondary toxicity hazards of the anticoagulant brodifacoum to American kestrels ( Falco sparverius ). Unpubl. report, Denver Wildlife Research Center. 24 pp. MRID# 80244, 00079312

U.S. Environmental Protection Agency. 1993. Wildlife Ex posure Factors Handbook . Office of Research and Development. December. EPA/600/R

- 93/187

U.S. Environmental Protection Agency. 1998a. Guidelines for Ecological Risk Assessment . United States Environmental Protection Agency (USEPA). Risk Assessment Forum . Office of Research and

### Page 37 of 60

Development. Available at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460 (Accessed June 19, 2009).

U.S. Environmental Protection Agency

. 1998b. Reregistration Eligibility Decision (RED): Rodenticide

Cluster . July 1998 . EPA 738

- R

- 98

- 007.

U.S. Environmental Protection Agency . 2004a. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs

. US EPA Office of Pesticide Programs, Environmental Fate and Effects

Division.

U.S. Environmental Prot ection Agency. 2004b. Potential Risks of Nine Rodenticides to Birds and Nontarget Mammals: a Comparative Approach. July 2004. US EPA Office of Pesticide Programs,

Environmental Fate and Effects Division.

U.S. Environmental Protection Agency. 2011. Risks of Diphacinone Use to the Federally Threatened Alameda Whipsnake ( Masticophis lateralis euryxanthus ), California Tiger Salamander ( Ambystoma californiense ), and the Federally Endangered Salt Marsh Harvest Mouse, California Tiger Salamander ( Ambystoma californiense ) Sonoma County Distinct Population Segment and Santa Barbara County Distinct Population Segment, and San Joaquin Kit Fox ( Vulpes macrotis mutica ). US EPA Office of Pesticide Programs, Environmental Fate and Effects Division. June 21, 2011.

Watt, B.E., A.T. Proudfoot, S.M. Bradberry, and J.A. Vale. 2005. Anticoagulant rodenticides. Toxicol.

Rev. 24(4):259

- 2 69

. Yu, C.C., Y.H. Atallah, and D.M. Whitacre. 1982. Metabolism and disposition of diphacinone in rats and mice. Drug Metabolism and Disp osition 10:645

- 648.



### Environmental Fate Data Submitted To Support Registration for PC Code 067701

Guideline: 161

- 1 Hydrolysis

------------------------------------------------------------------------------------- MRID: 95000 Atallah, Y.H.; Diaz, L.I .; McGhee, M.E.; et al. (1977) Aqueous Hydrolysis of Diphacinone: Report 408398, No. 3. (Un

- published study received Feb 17, 1981 under 876

- EX

- 35; submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:244385

- A)

MRID: 127706 Velsicol Chemical Corp. (1978) Chemical & Physical Properties: (Diphacinone). (Compilation; unpublished study received Aug 21, 1978 under 876

- EX

- 36; CDL:234817

- A)

MRID: 127709 Diaz, L.; Schwemmer, B.; Atallah, Y.; et al. (1976) Photolysis of 14C

- diphac inone in Aqueous Solution: Report 40839, No. 5. (Un

- published study received Aug 21, 1978 under 876

- EX

- 36; submitted by Velsicol Chemical Corp., Chicago, IL; CDL:234819

- D)

MRID: 134837 Velsicol Chemical, Corp. (1978) Chemical & Physical Properties: ?D iphacinone|. (Compilation; unpublished study received Jul 12, 1978 under 876

- EX

- 35; CDL:234419

- A)

MRID: 134840 Yu, C.; Atallah, Y.; Whitacre, D. (1976) Partition Coefficients for Diphacinone, VEL

5026, VEl

- 4207, VEL

- 4283 and Leptophos: Project No. 4083 98; Report No. 2. (Unpublished study received Jul 12, 1978 under 876

- EX

- 35; submitted by Velsicol Chemical Corp., Chi

- cago, IL;

CDL:234423

- D)

MRID: 136281 Atallah, Y.; Diaz, L.; McGee, M.; et al. (1977) Aqueous Hydrolysis of Diphacinone: Project No. 4 08398; Report No. 3. (Unpublished study received Jul 12, 1978 under 876

- EX

- 35; submitted by Velsi

- col Chemical, Corp., Chicago, IL; CDL:234423

- E)

MRID: 43582401 Riekena, C. (1995) Hydrolysis of Technical Diphacinone (2

- (Diphenylacetyl)

- 1H

indene

- 1,3(2 H)

- dione): Lab Project Number: BEL/0894/C143. Unpublished study prepared by Bell Labs, Inc. 40 p.

### Page 38 of 60

MRID: 92049010 Prasad, S. (1990) Haco, Co Phase 3 Summary of MRID 00095000. Diphacinone

- Hydrolysis Study: Project No. 408398. Prepared by Velsicol Che mical Corp. 18 p.

Guideline: 161

- 2 Photodegradation

- water

------------------------------------------------------------------------------------- MRID: 92049011 Prasad, S. (1990) Haco, Co Phase 3 Summary of MRID 00127709. Diphacinone

- Photodegradation in Water Study: Project No. 408398. Prepared by Velsicol Chemical Corp. 22 p.

Guideline: 162

- 1 Aerobic soil metabolism

------------------------------------ ------------------------------------------------- MRID: 128415 Atallah, Y.; Diaz, L.; Yu, C.; et al. (1978) Soil Degradation of the Rodenticide Diphacinone: Report 408398, No. 6. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; submitted by Vels i

- col Chemical Corp., Chicago, IL; CDL:234819

- E)

MRID: 42035001 Nomura, N.; Hilton, H. (1979) The Metabolism of (Carbon 14)

- Diphacinone to Carbon Dioxide in Two Hawaiian Sugarcane Soils under Aerobic Conditions. Unpublished study prepared by

Hawaiian Sugar Planters. 27 p.

MRID: 44260501 Riekena, C. (1997) Aerobic Soil Metabolism of (carbon 14)

- Diphacinone: (Final Report): Lab Project Number: 42430: BEL/0497/C192. Unpublished study prepared by Bell Labs, Inc. 116

p.

MRID: 92049012 Prasad, S. (19 90) Haco, Co Phase 3 Summary of MRID 00128415. Diphacinone

- Aerobic Soil Metabolism Study: Project No. 408398

- 6. Prepared by Velsicol Chemical Corp. 22 p.

Guideline: 162

- 2 Anaerobic soil metabolism

------------------------------------------------ ------------------------------------- MRID: 92049013 Prasad, S. (1990) Haco, Co Phase 3 Summary of MRID 00128415. Diphacinone

- Anaerobic Soil Metabolism Study: Project 408398

- 6. Prepared by Velsicol Chemical Corp. 24 p.

Guideline: 163

- 1 Leach/ads orp/desorption

------------------------------------------------------------------------------------- MRID: 127711 Weber, J. (19??) Leachability of Atrazine, Buthidazole, Bromacil, Diuron, Diphacinone, and Prometon through a Lakeland Sand. (Unpublished st udy received Aug 21, 1978 under 876

- EX

- 36; prepared by North Carolina State Univ., submitted by Velsicol Chemical Corp., Chicago, IL; CDL:234819

- G)

MRID: 127712 Nomura, N. (1978) Adsorption and Mobility of VEL 5026

- 14C in Five Hawaiian Sugarcane Soils. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by Hawaiian Sugar Planters' As

- soc., submitted by Velsicol Chemical Corp., Chicago, IL; CDL: 234819

- H)

MRID: 127713 Weber, J. (19??) Adsorption and Characterization of Diphacinone and Prometon on Lakeland Sand, Alamance Silt Loam, Ca

- Montmorillonite, and Acidic Soil Organic Matter. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by North Carolina State Univ., submitted by Velsicol Chemical Corp., Chicago, IL; CDL:234 819

- I)

MRID: 134841 Weber, J.; Swain, L. (19??) Report to ...: Leachability of Atzrazine, Buthiazole, Bromacil, Diuron, Diphacinone and Prometon through a Lakeland Sand. (Unpublished study received Jul 12, 1978

under 876

- EX

- 35; prepared by N.C. State U niv., submitted by Velsicol Chemical, Corp., Chicago, IL;

CDL:234423

- I)

MRID: 134842 Nomura, N. (1978) Adsorption and Mobility of VEL 5026

- 14C in Five Hawaiian Sugarcane Soils. (Unpublished study received Jul 12, 1978 under 876

- EX

- 35; prepared by Hawaiian Sugar Planters' Assoc., submitted by Vesicol Chemical, Corp., Chicago. IL; CDL: 2344 23

- J)

### Page 39 of 60

MRID: 134843 Weber, J.; Swain, L. (19??) Report to ...: Adsorption and Characterization of Diphacinone and Prometon on Lakeland Sand, Alamance Silt Loam, Ca

- montmorillonite and Acidic Soil Organic Mat

ter. (Unpublished study received Jul 12, 197 8 under 876

- EX

- 35; prepared by N.C. State Univ., submitted by Velsicol Chemical, Corp., Chicago, IL; CDL:234423

- K)

MRID: 43565801 Riekena, C. (1995) Leaching Through Soil of Technical Diphacinone (2

- (Diphenylacetyl)

- 1H

- indene

- 1,2(2H)

- dione): Lab Project Number: BEL/1194/C146. Unpublished study prepared by Bell Labs, Inc. 28 p.

MRID: 43582402 Riekena, C. (1995) Leaching Through Soil of Technical Diphacinone (2

- (Diphenylacetyl)

- 1H

- indene

- 1,3(2H)

- dione): Lab Project Number: BEL/1194/C146. Unpublished study prepared by Bell Labs, Inc. 28 p.

MRID: 92049014 Prasad, S. (1990) Haco, Co Phase 3 Summary of MRID 00127711. Leaching Study: ?Diphacinone|. Prepared by North Carolina State University. 19 p.

MRID: 92049015 Prasad, S. (1990) Haco, Co Phase 3 Summary of MRID 00127712. Diphacinone

- Leaching/Adsorption Study. Prepared by Hawaiian Sugar Planters Assn. 28 p.

MRID: 92049016 Prasad, S. (1990) Haco, Co Phase 3 Summary of MRID 00127713. Diphacinone

- Adsorption Study. Prepared by North Carolina S tate University. 26 p.

Guideline: 165

- 0 Accumulation Studies

-- General

------------------------------------------------------------------------------------- MRID: 127715 Ells, S. (1976) Kinetics of Aged Diphacinone in a Model Aquatic Ecosystem. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by EG & G, Bionomics, submitted by Velsicol Chemical Corp., Chicago, IL; CDL:234819

- K)



### Ecological Toxicity Data Su bmitted To Support Registration for PC Code 067701

Guideline: 71

- 1 Avian Single Dose Oral Toxicity

------------------------------------------------------------------------------------- MRID: 73753 Fink, R (1976) Final Report: Acute Oral LD I50^

-- Mallard Duck: Project No. 107

- 122. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- O)

MRID: 106914 Calo, C. (1975) Letter sent to R. Ostrowski dated Jul 28, 1975: Acute toxicity studies

-- Ramik mouse bait. (Unpublishe d study received Jun 28, 1977 under 876

- 124; submitted by Velsicol Chemical Corp., Chicago, IL; CDL:231295

- AP)

MRID: 128411 Fink, R. (1976) Acute Oral LD50

-- Mallard Duck

-- Technical Diphacinone: Project No.

107

- 122. Final rept. (Unpublished study received Jul 12, 1978 under 876

- EX

- 35; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chicago, IL; CDL:234422

- K)

MRID: 42245201 Campbell, S.; Hoxter, K.; Smith, G. (1991) Diphacinone Technical: An Acute Oral Toxicity Study with the Northern Bobwhite: Lab Project Number: 284

- 103. Unpublished study prepared by Wildlife International Ltd. 24 p.

Guideline: 71

- 2 Avian Dietary Toxicity

------------------------------------------------------------------------------------- MRID: 73751 Fink, R. (1976) Final Report: Eight

- Day Dietary LCI50^

-- Mallard Duck: Project No. 107

- 121. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- K)

### Page 40 of 60

MRID: 73752 Fink, R. (1976) Final Report: Eight

- Day Dietary LCI50^

-- Bobwhite Quail: Project No. 107

- 120. (Unpubli shed study received Aug 21, 1978 under 876

- EX

- 36; prepared by Truslow Farms, Inc., sub

mitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- N)

MRID: 79639 Fink, R. (1975) Final Report: Eight

- Day Dietary LCI50^

-- Bobwhite Quail: Project No. 107

- 1 17. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by Truslow Farms, Inc., sub

mitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- G)

MRID: 88743 Fink, R. (1975) Final Report: Eight

- Day Dietary LCI50^

-- Mallard Duck: Projec t No. 107

- 118. (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by Truslow Farms, Inc., sub

mitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- H)

MRID: 107432 Fink, R. (1976) Final Report: Eight

- day Dietary LC50

-- Bobwhite Q uail: ?Technical Diphacinone|: Project No. 107

- 120. (Unpub

- lished study received May 12, 1976 under 876

- 124; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chicago, IL; CDL:225250

- A)

MRID: 127697 Fink, R. (1975) Eight

- day Dieta ry LC50: Bobwhite Quail: Diphaci

- none: Project No. 107

- 117. Final rept. (Unpublished study re

- ceived Oct 29, 1975 under 876

- 184; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chicago, IL; CDL: 222349

- A)

MRID: 127698 Fink, R. (1975) Eight

- day Dietary LC50: Mallard Duck: Diphacinone: Project No. 107

- 118. Final rept. (Unpublished study received Oct 29, 1975 under 876

- 184; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chicago, IL; CDL:222350

- A)

MRID: 128412 Fink, R. (1976) Eight

- day Dietary LC50

-- Bobwhite Quail

-- Technical Diphacinone: Project

No. 107

- 120. Final rept. (Unpublished study received Jul 12, 1978 under 876

- EX

- 35; prepared by Truslow Farms, Inc., submitted by Velsicol Chemical Corp., Chica go, IL; CDL:234422

- N)

MRID: 128413 Fink, R. (1976) Eight

- day Dietary LC50

-- Mallard Duck

-- Technical Diphacinone: Project

No. 107

- 121. Final rept. (Unpublished study received Jul 12, 1978 under 876

- EX

- 35; prepared by Truslow Farms, Inc., submitted by Ve lsicol Chemical Corp., Chicago, IL; CDL:234422

- O)

MRID: 42408801 Long, R.; Foster, J.; Hoxter, K. et al. (1992) Diphacinone Technical: A Dietary LC50 Study with the Northern Bobwhite: Lab Project Number: 284

- 101A. Unpublished study prepared by Bell

Lab s, Inc. 32 p.

MRID: 42408802 Long, R.; Foster, J.; Hoxter, K. et al. (1992) Diphacinone Technical: A Dietary LC50 Study with the Mallard: Lab Project Number: 284

- 102B. Unpublished study prepared by Wildlife Intl. 36

p.

Guideline: 71

- 3 Wild mammal toxicity

------------------------------------------------------------------------------------- MRID: 2467 Pank, L.F.; Hirata, D.N. (1976) Primary and Secondary Toxicity of Anticoagulant Rodenticides: Job Completion Report: Work Unit DF

- 103.7. (Unp ublished study received on unknown date under unknown admin. no.; prepared by U.S. Fish and Wildlife Service, Denver Wildlife Research Center, Wildlife Damage Research Station, submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:

230307

- B)

MRID: 24 68 U.S. Fish and Wildlife Service, Denver Wildlife Research Center (1973) Vertebrate Damage Control Research: 1973 Annual Report. By Denver Wildlife Research Center and U.S. Agency for Interna

tional Development, Office of Agriculture and Fisheries. Den

- ver, Colo.: U.S. Fish and Wildlife Service. (Available from: U.S. Fish and Wildlife Service, Denver Wildlife Research Center, Denver, CO; pp. 23

- 25 only; also~In~unpublished submission re

- ceived on unknown date under unknown admin. no.; submitted by Vel sicol Chemical Corp., Chicago, Ill.; CDL:230307

- D)

### Page 41 of 60

Guideline: 71

- 5 Simulated or Actual Field Testing

------------------------------------------------------------------------------------- MRID: 45855101 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus beecheyi): Final Report: Lab Project Number: 00

- 0471: 29: 30. Unpublished study prepared by University of Cal ifornia, Davis. 131 p.

MRID: 46911901 Mach, J. (2006) Secondary Hazard Study Using Diphacinone

- Killed Rodents Fed to Domestic Ferrets (Mustela putorius furo): Final Report. Project Number: 05038, 06002. Unpublished study prepared by Genesis Laborator ies, Inc. 32 p.

MRID: 48373002 Ingenloff, K.; Soniat, M. (2011) Exposure of Kaput Field Rodent Bait B to Northern Bobwhite Quail (Colinus virginianus). Project Number: 10004. Unpublished study prepared by Genesis Laboratories, Inc. 44 p.

MRID: 4837 3005 Poche, D. (2011) Exposure of Kaput Field Rodent Bait B to Mallard Ducks (Anas platyrhynchos). Project Number: 10003. Unpublished study prepared by Genesis Laboratories, Inc. 47 p.

Guideline: 72

- 1 Acute Toxicity to Freshwater Fish

----------- -------------------------------------------------------------------------- MRID: 60603 Bentley, R.E. (1975) Acute Toxicity of Ramik Mouse Bait to Bluegill (Lepomis macrochirus), Rainbow Trout (Salmo gairdneri), and Channel Catfish (Ictalurus punctatus). (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by Bionomics, EG&G, submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- E)

MRID: 60607 Bentley, R.E. (1975) Acute Toxicity of Diphacinone Technical to Bluegill (~Lepomis

macr ochirus~), Channel Catfish (~Ictalurus punctatus~), and Rainbow Trout (~Salmo gairdneri~). (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by EG&G, Bionomics, submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- L)

MRID: 1 27699 Bentley, R. (1975) Acute Toxicity of Ramik Mouse Bait to Bluegill (Lepomis macrochirus), Rainbow Trout (Salmo gairdneri), and Channel Catfish (Ictalurus punctatus). (Unpublished study re

- ceived Oct 29, 1975 under 876

- 184; prepared by Bionomics, EG & G, submitted by Velsicol Chemical Corp., Chicago, IL; CDL; 222352

- A)

MRID: 92049005 Kelley, J. (1990) Haco Co. Phase 3 Summary of MRID 00060607. Acute Toxicity of Diphacinone Technical to Bluegill, Channel Catfish, and Rainbow Trout. Prepared by EG& G, Bionomics. 17 p.

Guideline: 72

- 2 Acute Toxicity to Freshwater Invertebrates

------------------------------------------------------------------------------------- MRID: 42282201 Putt, A. (1992) Diphacinone Technical: Acute Toxicity to Daphnids ( Daphnia magna)

under Flow

- through Conditions: Lab Project Number: 91

- 9

- 3938: 12455. 1290. 6100. 115: 90

- 10A. Unpublished study prepared by Springborn Labs, Inc. 66 p.

Guideline: 72

- 3 Acute Toxicity to Estuarine/Marine Organisms

------------------------------------------------------------------------------------- MRID: 60604 Heitmuller, T. (1975) Acute Toxicity of Ramik to Pink Shrimp (Penaeus duorarum) and Fiddler Crabs (Uca pugilator). (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; prepared by

Bionomics

-- EG&G, Inc., submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- F)

MRID: 60608 Heitmuller, T. (1975) Acute Toxicity of Diphacinone to Pink Shrimp (~Penaeus duorarum~) and Fiddler Crabs (~Uca pugilator~ ). (Unpublished study received Aug 21, 1978 under 876

- EX

- 36; pre

pared by Bionomics

-- EG&G, Inc., submitted by Velsicol Chemical Corp., Chicago, Ill.; CDL:234818

- M)

Guideline: 96

- 5 Avian toxicants

### Page 42 of 60

--------------------------------------------------- ---------------------------------- MRID: 41375801 Keith, J.; Hirata, D.; Espy, D.; et al. (1990) Field Evaluation of 0.00025% Diphacinone Bait for Mongoose Control in Hawaii: Final Report: Lab Project Number: QA

- 16. Unpublished study prepared by Denver W ildlife Research Center. 52 p.

Guideline: 96

- 12 Rodenticides on farms and rangelands

------------------------------------------------------------------------------------- MRID: 41375801 Keith, J.; Hirata, D.; Espy, D.; et al. (1990) Field Evaluat ion of 0.00025% Diphacinone Bait for Mongoose Control in Hawaii: Final Report: Lab Project Number: QA

- 16. Unpublished study prepared by Denver Wildlife Research Center. 52 p.

MRID: 43805001 Marsh, R.; Howard, W. (1975) A Field Evaluation of Ramik for Ground Squirrel Control, March 7, 1975: Lab Project Number: UR

- 95

- 01. Unpublished study prepared by Hacco, Inc. 14

p.

MRID: 43805002 Marsh, R.; Howard, W. (1976) Report on the Laboratory Efficacy of Ramik for Belding's Ground Squirrel: Lab Project Num ber: UR

- 95

- 03. Unpublished study prepared by Hacco, Inc. 8

p.

MRID: 44453703 Hacco, Inc. (1997) Field Efficacy of Diphacinone Grain Baits: Lab Project Number: UR

97

- 01. Unpublished study. 10 p.

MRID: 45855101 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus beecheyi): Final Report: Lab Project Number: 00

- 0471: 29: 30. Unpublished study prepared by Universit y of California, Davis. 131 p.

MRID: 45855102 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and Retrieving Rodent Carcasses From Burrows: (Diphacinone and Chlorophacinone Baits): Lab Project Number: QA

- 879. Unpub lished study prepared by National Wildlife Research Center. 29 p. (OPPTS 850.2500)

MRID: 46117301 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 0.01% Diphacinone and Chlorophacinone Baits for Controlling Cali fornia Ground Squirrels (Spermophilus beecheyi). Unpublished study prepared by University of California, Davis. 61 p.

MRID: 46117302 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and Retrieving Rodent Carcasses fr om Burrows. Unpublished study prepared by U.S. Dept. of Agriculture, APHIS, ADC. 22 p.

MRID: 46117303 Goodall, M.; Primus, T.; Johnston, J. (2002) Determination of Cholorphacinone (sic) and Diphacinone Residues in California Ground Squirrels and Non

- Target Animals. Unpublished study prepared by U.S. Dept. of Agriculture, APHIS, ADC. 19 p.

MRID: 46271501 Baroch, J.; Malkov, V. (2004) Field Efficacy of Kaput Pocket Gopher Bait (0.005% Diphacinone) for the Control of the Plains Pocket Gopher (Geo mys bursarius): Amended Final Report. Project Number: 02011. Unpublished study prepared by Genesis Laboratories, Inc. 118 p.

MRID: 46749601 Spurr, E.; Lindsey, G.; Perry, C.; et. al. (2003) Effectiveness of Hand

- Broadcast Application of Baits Containi ng 0.005% Diphacinone in Reducing Rat Populations in Hawaiian Forests: Final Report. Project Number: QA/02A. Unpublished study prepared by U.S. Geological Survey. 224 p.

MRID: 46749602 Spurr, E.; Foote, D.; Perry, C.; et. al. (2003) Efficacy of Aerial Broadcast Application of Baits Containing 0.005% Diphacinone in Reducing Rat Populations in Hawaiian Forests: Final Report. Project Number: QA/02B. Unpublished study prepared by U.S. Geological Survey. 191 p.

### Page 43 of 60

MRID: 46966511 Borchert, J. (2006) Rock S quirrel Simulated Field Study Using Field Rodent Bait: 30

- Day Test (Spermophilus variegates) of Kaput Field Rodent Bait B. Project Number: 05010. Unpublished study prepared by Genesis Laboratories Inc. 89 p.

MRID: 47114204 Borchert, J. (2005) Field Ef ficacy of Petersen Field Rodent Bait (0.005% Diphacinone) for Controlling Black

- Tailed Prairie Dogs (Cynomys ludovicianus): Final Report. Project Number: 06014. Unpublished study prepared by Genesis Laboratories, Inc. 145 p.

MRID: 47185301 Dunlevy, P. ; Scharf, L. (2007) Eradication of Norway Rats Using Ramik Green in the Bay of Islands, Adak Island, Alaska: Interim Report. Unpublished study prepared by Alaska Maritime National Wildlife Refuge. 52 p.

MRID: 47226201 Bruening, J. (2007) Field Efficacy of Kaput

- D Prairie Dog Bait for Controlling Black

Tailed Prairie Dogs (Cynomys ludovicianus). Project Number: N07004. Unpublished study prepared by Genesis Laboratories, Inc. 108 p. MRID: 47430701 Bruening, J. (2008) Field Efficacy of Kaput

- D Combo Ba it (EPA Reg. No. 72500

- 11) for Controlling Black

- Tailed Prairie Dogs (Cynomys ludovicianus). Project Number: 07021, GL/138261/41/3/1. Unpublished study prepared by Genesis Laboratories, Inc. 117 p.

MRID: 48551901 Symmes, C. (2010) Field Efficacy of Fi eld Rodent Bait B (Kaput

- D Combo Bait) for Controlling Wyoming Ground Squirrels (Spermophilus elegans). Project Number: 10001. Unpublished study prepared by Genesis Laboratories, Inc. 150p.

MRID: 49244501 Benton, S. (2013) Comparative Field Palatability of Two Formulations of Kaput Field Rodent Bait B Using California Ground Squirrels (Spermophilus beechey). Project Number: N13008. Unpublished study prepared by Genesis Laboratories, Inc. 35p.

MRID: 49502601 Baldwin, R. (2014) Field Efficacy of 0.005 % Diphacinone Pellets for Control of California Ground Squirrels via Bait Station Application. Project Number: BEL/0613/BE831. Unpublished study prepared by University of California Kearney Agricultural Center. 127p.

MRID: 49543001 Baldwin, R. (2015) Field Efficacy of 0.005% Diphacinone Pellets for Control of California Ground Squirrels via Spot Treatment Application. Project Number: BEL/0614/BE873. Unpublished study prepared by University of California, Davis. 112p.

Guideline: 96

- 17 Mammalia n predacides

------------------------------------------------------------------------------------- MRID: 40565501 Keith, J.; Hirata, D. (1987) Determination of an Acute, Oral LD50 for Diphacinone against Mongooses (Herpestes auropunctatus): Mongoose Proje ct (963). Unpublished study prepared by Denver Wildlife Research Center. 6 p.

MRID: 40565502 Keith, J.; Hirata, D. (1986) Laboratory Trials To Determine Minimum Levels of Diphacinone in Bait that are Lethal to Mongooses (Herpestes auropunctatus): Mongoose Project (963). Unpublished study prepared by Denver Wildlife Research Center . 21 p.

MRID: 40565503 Keith, J.; Hirata, D. (1987) Laboratory Trial To Determine Mortality of Mongooses (Herpestes auropunctatus) Fed 0.00025% Diphacinone Bait: Mongoose Project (963). Unpublished study prepared by Denver Wildlife Research Center. 6 p.

MRID: 40565504 Keith, J.; Espy, D.; Hirata, D. (1987) Small Field Efficacy Trials using Diphacinone Bait against Mongooses (Herpestes auropunctatus): Mongoose Project (963). Unpublished study prepared by Denver Wildlife Research Center. 8 p.

Guid eline: 810.3300 Treatments to control pests of humans and pets

-------------------------------------------------------------------------------------

### Page 44 of 60

MRID: 46966510 Borchert, J. (2006) Field Efficacy of Field Rodent Bait for Controlling Black

- Tailed Prairie Dogs (Cynomys ludovicianus) of Kaput Field Rodent Bait B. Project Number: 05009. Unpublished study prepared by Genesis Laboratories, Inc. 141 p.

MRID: 46966512 Borchert, J. (2006) Field Efficacy Data of Field Rodent Bait B: California Ground

S quirrels (Spermophilus beecheyi) and Fleas of Kaput Field Rodent Bait B . Project Number: 05019. Unpublished study prepared by Genesis Laboratories, Inc. 371 p.

MRID: 47603301 Poche, R. (2008) Determining the Blood Titer Levels and the Effectiveness o f Kaput Field Rodent Bait B Against Oropsylla spp. Fleas on Black

- Tailed Prairie Dogs (Cynomys Ludovicianus). Project Number: 08015, 138261/41/3/1, 82/66/6/9. Unpublished study prepared by Genesis Laboratories, Inc. 123 p.

MRID: 47633201 Poche, R. (20 08) Determining the Blood Titer Levels and the Effectiveness of Kaput Field Rodent Bait B Against Oropsylla spp. Fleas on Black

- Tailed Prairie Dogs (Cynomys ludovicianus): Final Report. Project Number: 08015A1, 08015. Unpublished study prepared by Genesi s Laboratories, Inc. 6 p.

MRID: 47858501 Ellis, C. (2009) Novel Commensal Rodent Pellet #2: Determining the Blood Titer Levels and the Effectiveness of Scimetrics Ltd. Corp., Kaput Combo Baits Against Xanopsylla cheopis Fleas on Laboratory Norway Rats ( Rattus norvegicus). Project Number: 09002. Unpublished study prepared by Genesis Laboratories, Inc. 268 p.

Guideline: 850.2500 Field testing for terrestrial wildlife

-------------------------------------------------------------------------------- ----- MRID: 45855101 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing 0.005% and 0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus beecheyi): Final Report: Lab Project Number : 00

- 0471: 29: 30. Unpublished study prepared by University of California, Davis. 131 p.

MRID: 45855102 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and Retrieving Rodent Carcasses From Burrows: (Diphacinone and Chlorophacinone Baits): Lab Project Number: QA

- 879. Unpublished study prepared by National Wildlife Research Center. 29 p. (OPPTS 850.2500)

MRID: 46117301 Salmon, T.; Whisson, D.; Gorenzel, W. (2001) Field Efficacy Studies Comparing

0.005% and 0.01% Diphacinone and Chlorophacinone Baits for Controlling California Ground Squirrels (Spermophilus beecheyi). Unpublished study prepared by University of California, Davis. 61 p.

MRID: 46117302 VerCauteren, K.; Pipas, M.; Bourassa, J. (2002) A Camera and Hook System for Viewing and Retrieving Rodent Carcasses from Burrows. Unpublished study prepared by U.S. Dept. of Agriculture, APHIS, ADC. 22 p.

MRID: 46117303 Goodall, M.; Primus, T.; Johnston, J. (2002) Determination of Cholorphacinone (sic) and Dip hacinone Residues in California Ground Squirrels and Non

- Target Animals. Unpublished study prepared by U.S. Dept. of Agriculture, APHIS, ADC. 19 p.

### Page 45 of 60



### Ecological Toxicity Data Su bmitted To Support Registration for PC Code 067705

72

- 1 Acute Toxicity to Freshwater Fish

------------------------------------------------------------------------------------- MRID: 43249501 Machado, M. (1994) Diphacinone, Sodium Salt

-- Prolonged Acute Toxicity to Bluegill Sunfish (Lepomis macrochirus) under Flow

- Through Cond itions: Amended Final Report: Lab Project Number: 94/3/5191: 12455/1193/6105/195. Unpublished study prepared by Springborn Laboratories, Inc. 84 p.

MRID: 43249502 Machado, M. (1994) Diphacinone, Sodium Salt

-- Prolonged Acute Toxicity to Rainbow Trout (Sal mo gairdneri) under Flow

- Through Conditions: Final Report: Lab Project Number: 94/3/5216: 12455/1193/6106/195. Unpublished study prepared by Springborn Laboratories, Inc. 83 p.

### Page 46 of 60



# Appendix A: Label Use Information for diphacinone and diphacinone sodium salt based on BEADs summary report

Use Single Max Application

Rate Max

App. Rate per

Year Min Re

treatment

Interval (days) Max # of

App s. Per Year (or Crop Cycle) Application

Methods



### Diphacinone

A gricultural C rops / S oils (U nspecified ) 0.0000126

lb / burrow NS 14 3

Ground Bait Treatment, Spot Treatment 0.003 lb / bait station(s) NS NS

A gricultural F allow / I dleland

/ C onservation Reserve 0.0003 lb / bait station(s) or

0.005 lb /ac NS NS NS

A gricultural /F arm S tructures
/ B uildings and Equipment NS NS NS

A gricultural U ncultivated

A reas 0.0003 lb / bait

stations NS NS NS

Ground

Bait Treatment A irports / L anding Fields

0.0001 lb / placement or

0.00000219 lb / bait station(s)

NS NS NS A nimal B urrows , H arborages

or D ens Of P lague R eservoir

Hosts

A utomobiles, Taxis,

L imousines , R ecreational

V ehicles , & T ires

C ommercial T ransportation

V ehicles (A ll or U nspecified )

C ommercial / I nstitutional /

I ndustrial P remises /

E quipment (I ndoor )

C ommercial / I nstitutional /

I ndustrial Floors

C ommercial / I nstitutional /

I ndustrial P remises /

E quipment ( Outdoor ) 0.0003 lb / placement

C hristmas Tree P lantations 0.001 lb / ac Aerial, Ground

Broadcast

F encerows / H edgerows 0.0002 lb / bait station(s) Ground

Bait Treatment

F ood P rocessing P lant N on

F ood H andling Areas 0.0001 lb / placement NS NS NS Ground

Bait Treatment

Food P rocessing P lant

P remises (N on

- Food

Contact )

F orest P lanting (R eforestation P rograms ) 0.001 lb / ac Ground Bait Treatment,

### Page 47 of 60 (T ree F arms , T ree
P lantations

, etc .) Broadcast

Forest T rees (A ll or

U nspecified ) 0.0000126 lb /

burrow NS 14 3

Ground

Bait Treatment G olf C ourse T urf

H ousehold / D omestic

D wellings I ndoor P remises

H ousehold / D omestic

D wellings Outdoor P remises 0.0001 lb / placement

NS NS NS N onagricultural O utdoor

B uildings / Structures 0.0002 lb / bait station(s)

N onagricultural R ight

- of

Way / F encerows /

H edgerows 0.0136 lb / ac

N onagricultural U ncultivated

A reas / S oils 0.001 lb / ac

NS NS 1 Aerial, Ground, Broadcast,

Bait Treatment N ursery S tock

NS O rchards (U nspecified )

O rnamental and/or S hade

Trees 0.00002188 lb / bag

Ground

Bait Treatment O rnamental W oody S hrubs

and Vines

O rnamental L awns and T urf 0.0000126 lb /

burrow 14 3

P astures 0.0136 lb /ac NS 4

P ublic B uildings / S tructures (V ert. P est C ontrol ) 0.0001 lb / placement NS NS

R ailroad B oxcars
R angeland 0.0136 lb /ac 14 4 Ground Bait Treatment, Spot Treatment R ecreational A reas 0.0000126 lb /

burrow 14 4

R efuse / S olid W aste S ites (O utdoor )

0.0001 lb / placement

NS NS Ground

Bait Treatment R ight

- of

- Way (R ailroad )

S hips and Boats

S treams / R ivers /C hanneled

W ater

S wamps /M arshes / W etlands

/ S tagnant W ater 0.0003 lb / bait station(s)

W ide A rea / G eneral I ndoor

T reatment 0.0001 lb / placement W ide A rea / G eneral Outdoor

T reatment (P ublic H ealth

Use ) 

### Diphacinone Sodium Salt

A gricultural /F arm S tructures
/ B uildings and Equipment 0.0001 lb / bait station(s) NS NS NS Ground

Bait Application (Bait/Liquid) Commercial / Institutional /

Industrial Premises / Equipment (Indoor) NS = not specified

### Page 48 of 60



# Appendix B : Summary of Ecotoxicity Data for

Di phacinone

Table B

- 1. Freshwater Fish Acute Toxicity of Diphacinone
Species % a.i. 96

- hourLC 50 (mg a.i./L) Toxicity

Category MRID No. Study Classification

Bluegill sunfish, ( Lepomis macrochirus ) 95.8 7.5 Moderately toxic 432495 01 Acceptable

Rainbow trout, ( Onchorhynchus mykiss ) 95.8 2.6 Moderately toxic 43249502 Acceptable



### Table B

- 2 . Freshwater Invertebrate Acute Toxicity of Di phacinone
Species % a.i. 48

- hourEC 50 (mg /L) Toxicity

Category MRID No. Study Classification

Water flea ( Daphnia magna ) 98.7 1.8 Moderately toxic 42282201 Acceptable



### Table B

- 3: Avi an Acute Toxicity to Di phacinone

Species % A.I. Toxicity Endpoint Toxicity

Classification MRID Status

Acute Single Oral Dose

Bobwhite quail ( Colinus virginianus ) 96.9 LD 50 = 1630 mg a.i./kg

- bw Slightly toxic 42245201 Supplemental

Bobwhite quail n.a. LD 50 = 2014 mg a.i./kg

- bw Practically non

toxic Rattner et al 2010 Supplemental (Quantitative)

Mallard duck ( Anas platyrhynchos ) n.a. LD 50 = 3158 mg a.i./kg

- bw Practically non

toxic 00 128411

American kestrel 99.2 LD 50 = 98.6 mg a.i./kg

- bw Moderately

toxic Rattner et al 2011 Supplemental (Quantitative)

Acute Dietary

Bobwhite quail 96.9 LC 50 > 5000 mg a.i./kg

- diet Practically non

toxic 42408801 Acceptable

Mallard duck 96.9 LC 50 =906 mg a.i./kg

diet Moderately

toxic 42408802 Acceptable

### Page 49 of 60



### Table B

- 4 : Mammalian Acute Toxicity to Di phacinone

Test Type % A.I. Toxicity Endpoint Toxicity

Classification MRID Status

Acute oral (gavage) single dose

Laboratory rat (males only) Rattus norvegicus tech LD 50 = 1.9 mg a.i./kg

- bw Very highly

toxic Byers 1978

Ecotox Ref #

J69367 supplemental

Laboratory rat tech LD 50 = 2.46 mg a.i./kg

- bw Very highly

toxic 00060605 qualititative 1

Pine vole LD 50 = 57.7 mg a.i./kg

- bw Moderately

toxic Byers 1978

Ecotox Ref #

J69367 qualitative Meadow vole LD 50 = 14 mg a.i./kg

- bw Highly toxic

Pine vole LD 50 = 102 mg a.i./kg

- bw Moderately

toxic

coyote LD 50 = 0.6 mg a.i./kg

- bw Very highly

toxic Savarie et al.

1979 00079312, qualitative

mongoose LD 50 = 0.18 mg a.i./kg

- bw Very highly

toxic 40565501 supplemental

Cats and dogs LD 50 ranged from 0.88 to 15 mg a.i./kg

- bw Very highly

toxic to Highly toxic LiphaTech,

Inc, 1997 qualitative

Acute Dietary

Laboratory Rat 99.9 LC 50 = 2.08 mg a.i./kg

- diet Very highly

toxic. Teeters 1981

(TNM 75) 2 Supplemental

Laboratory Rat 99.9 LC 50 = 2.54 mg a.i./kg

- diet Very highly

toxic. Teeters 1981

(TNM 51) 2 Supplemental

1 HED or RD DER not located, upon EFED review data presumed to meet ‘qualitatitive’ classification

2 Teeters, W.R.(1981) Diphacinone technical: Toxicity to Laboratory Rat. (U.S. Environmental Protection Agency, Pesticides Regulation Div., Agricultural Resea rch Center, Animal Biology Laboratory, unpublished report.)

### Page 50 of 60



# Appendix C . Screening Level Models to Evaluate Potential Importance of Drinking Water and Inhalation Exposure Pathways

### Page 51 of 60



### SIP ( Screening Imbibition Program, v1.0) Inputs and Conclusions
Table 1. Inputs

Parameter Value

Chemical name diphacinone

Solubility (in water at 25 o C; mg/L) 0.3

Mammalian LD 50 (mg/kg

- bw) 1.9

Mammalian test species laboratory rat
Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg

- bw)

Mammalian test species laboratory rat
Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg

- bw) 1630

Avian test species northern bobwhite quail
Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg

- diet) 0
Bobwhite quail NOAEC (mg/kg

- diet) 0
NOAEC (mg/kg

- diet) for other bird species 0
Body weight (g) of other avian species

NOAEC (mg/kg

- diet) for 2nd other bird species 0

Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg

- bw) 0.0516 0.0516
Adjusted toxicity value (mg/kg

- bw) 1.4614 0.0000

Ratio of exposure to toxicity 0.0353 0.0000

Conclusion* Drinking water exposure alone is NOT a potential
concern for mammals Due to insufficient data, risk cannot be precluded

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg

- bw) 0.2430 0.2430

Adjusted toxicity value (mg/kg

- bw) 1174.3001 0.0000

Ratio of exposure to acute toxicity 0.0002 0.0000

Conclusion* Drinking water exposure alone is NOT a potential
concern for birds Due to insufficient data, risk cannot be precluded

* *Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effect s to non

- target animals.

### Page 52 of 60

Welcome to the EFED Screening Tool for Inhalation Risk

This tool is designed to provide the risk assessor with a rapid method for determining the potential

significance of the inhalation exposure route to birds and mammals in a risk assessment.

Input

Application and Chemical Information

Enter Chemical Name diphacinone

Enter Chemical Use rodenticide Is the Application a Spray? (enter y or n) n If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 340.38 Enter Chemical Vapor Pressure (mmHg) 1.00E

- 08 Enter Application Rate (lb a.i./acre) 0.005

Toxicity Properties

Bird

Enter Lowest Bird Oral LD 50 (mg/kg bw) 1630 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD 50 (mg/kg bw) 1.9

Enter Lowest Rat Inhalation LC 50 (mg/L) 0.0006 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation ( mg/m 3 ) 1.83E

- 04

Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 2.30E

- 05

Adjusted Inhalation LD 50 2.87E+00

Ratio of Vapor Dose to Adjusted Inhalation LD 50 8.02E

- 06 Exposure not Likely Significant

Maximum Post

- treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 not applicable not applicable

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation ( mg/m 3 ) 1.83E

- 04

Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 2.89E

- 05

Adjusted Inhalation LD 50 3.57E

- 02

Ratio of Vapor Dose to Adjusted Inhalation LD 50 8.10E

- 04 Exposure not Likely Significant

Maximum Post

- treatment Spray Inhalation Dose (mg/kg) not applicable

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 not applicable not applicable

### Page 53 of 60



# Appendix D . Wildlife Mortality Incidents Attributed to Use of Diphacinone

The table below is based on the Summary Table that was included in Docket ID EPA

HQ

- OPP

- 2011

- 0718 (“ Risks of Non

- Compliant Rodenticides to Nontarget Wildlife

- Appendix D

- Wildlife Mortality Incidents”; Document ID EPA

- HQ

- OPP

- 2011

- 0718

- 0010) . The table wa s updated to include additional incidents and additional information on previously reported incidents that was available to the Agency as of 2013. Any additional incidents reported to the Agency after 2013 for diphacinone have not been

added to the table b elow.

For each of the incidents reported below, insufficient information was available to ascertain legality of the pesticide use.

### Page 54 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

B000640

- 001 1987 Probable CA Residential Kit Fox (1) A San Joaquin kit fox was found dead at a nursery near a university where anticoagulant baits had been applied for ground squirrel control. Unclotted whole blood was present in the abdomen. Several diffuse areas of hemorrhages were present in the lungs. The stomach contained a few grass stems and some sand. The intestines were empty. Diphacinone residues at 0.18 ppm were detected by ELISA.

B000641

- 001 1986 Highly probable CA Field Raccoon (1), Mountain Lion (1) The California Department of Fish and Game reported this

incident where a raccoon and mountain lion were found

dead near a stream. Pooled free blood was found in the

raccoon
, and in the mountain lion there were pinpoint and streaked hemorrhages in the small intestine and colon. Blood samples were analyzed and the results showed 55 ppm diphacinone in the raccoon and 45 ppm diphacinone

in the mountain lion.

I004768

- 001 1996 Highly probable NY N/R Deer (1) A white

– tailed deer had been found dead and submitted to the Wildlife Pathology Unit. The presence of fairly large maggots in the carcass suggests this deer had been dead for several weeks. An analysis of the liver detected diphacinone residues at 0.2 pp m.

I004769

- 001 1996 Highly probable NY Residential Deer (1) A white

- tailed deer was found dead in a residential area with hemorrhages appearing like minor bruising and a hemorrhagic subcutaneous edema was found in the vicinity of the left shoulder and adjoining brisket area. The stomach was full of whole corn, veg etation, and water. An analysis of t he liver detected diphacinone residues at 0.93 ppm.

### Page 55 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

B0000

- 300

- 84 1997 Highly probable NY Residential Squirrel (1) A squirrel was found in the yard of a resident. Necropsy showed areas of subcutaneous edema and hemorrhage found over the ventral thorax and upper abdomen along with the right foreleg and on the right side of the head.

The stomach contents were normal in appearance and odor. An analysis of the liver detected diphacinone residues at 2.0 ppm.

I006306

- 013 1998 Highly probable NY N/R Snowy Owl (1) A snowy owl was found dead and an analysis of its liver detected diphacinone residues. There were no residue numbers provided with the report.

I007107

- 007 1997 Possible NY N/R Turkey vulture (1) This incident is one of the incidents reported on the consolidated report for the year 1997 submitted by California Department of Fish and Game. After an analysis the Pesticide Investigation Unit determined the loss of the turkey vulture was due to diphacinone poisoning.

I005417

- 004 1989 Possible CA N/R Rabbits (12) Twelve rabbits were found dead after a hand application of sodium monofluoroacetate. Necropsies of two showed severe bleeding. A kidney from each of two rabbits was analyzed for sodium monofluoroacetate but the finding was negative. Subsequ ently it was learned that diphacinone had been used in the area, and the symptoms

found in the rabbits were in accord with what would be expected from diphacinone. No anticoagulant residues were detected in the blood, but it is possible that an anticoagul ant in the blood metabolized before death. No analyses of liver samples were conducted.

### Page 56 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

I007107

- 014 1997 Highly probable CA N/R Coyote (1) The carcass of a yearling female coyote was recovered from the Santa Monica Mountains on October 9, 1997. Diphacinone was detected in the liver at 1.3 ppm, 0.1 ppm in the blood collected from the thoracic cavity and 0.16 ppm in the stomach contents. Brodifacoum was identified in the liver at 0.083 ppm. Free blood was present in the body cavities.

I007488

- 00 4 1998 Highly probable VA Residential Squirrel (2) Two grey squirrels were found dead and collected by the Virginia Department of Game and Inland Fisheries. The stomach and small intestine of the first squirrel contained

abundant unclotted blood mixed with a scant amount of tan granular material. The small intestine for the second squirrel contained a smaller amount of unclotted blood. The thoracic cavities of both squirrels were filled with unclotted blood. Liver analysis detected bromadiolone

and d iphacinone residues in pooled liver samples from both squirrels at 4.94 for bromadiolone and 3.41 ppm for diphacinone.

I009270

- 001 1999 Probable NY Residential Hawk (1) A red

- tailed hawk was found moribund in a residential area. Small fish, appearing to be sardines were in the stomach. The bird was very anemic and lacked blood volume. An analysis of the liver detected diphacinone residues at 0.34 ppm.

I011518

- 001 20 00 Possible NY Residential Squirrel (1) A grey squirrel was found dead in a residential yard. There was a hemorrhage over the right orbit of the eye. The stomach contained a finely ground material. A small area of subcutaneous hemorrhage was present over the dorsal thorax. Blunt impact trauma was the immediate cause of death, but diphacinone residues detected at 1.02 ppm may have been contributing.

### Page 57 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

I013810

- 006 1993 Probable NY N/R Snowy Owl (1) This incident is part of the Contaminant Exposure and

Effects

– Terrestrial Vertebrates (CEE

- TV) Database, Version 3.3, October 2002 report. A snowy owl was found dead and its liver showed traces of diphacinone that were suspected as the cause of death.

I014884

- 018 2003 Possible CA N/R Pigeon (1) The California Department of Fish and Game report of wildlife incidents involving pesticides for calendar years 2002 and 2003 identified an incident with a pigeon having diphacinone and brodifacoum levels detected in its tissues.

No chemical residue values we re provided.

I019839

- 001 2008 Probable GA Residential Squirrel (1) A homeowner reported that approximately eight squirrels have been found dead in her yard and in the adjacent neighbor’s yard. Diphacinone was detected in the liver of a squirrel tested at 3.6 ppm. Severe, acute, multifocal, subcutaneous, and intramuscula r hemorrhaging was
present.

### Page 58 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

I019968

- 001 2008 Possible CA Field Bobcat (1) In 2008, Department of Fish and Game Office of Spill Prevention and Response staff in Santa Cruz responded to an incident near a lettuce field near Morro Cojo Slough involving several dead Canada geese. A dditional geese

were found dead at the site for several weeks after the initial incident report. The total number of dead geese was estimated to be 70. In addition, two turkey vultures, a red

tailed hawk, a barn owl, and a bob cat were found dead in the vicinity. The geese an d the predators and scavengers showed signs of anticoagulant toxicity. The bobcat was

the o nly one that tested positive for diphacinone (0.34 ppm)

- most of the other animals tested, tested positive for

ch lorophacinone.

I022935

- 001 2011 Highly probable CA Field Bald eagle (1) A bald eagle was found dead in Kern County, CA in 2011. The eagle carcass was transported and received by

California Animal Health & Food Safety Lab on 1/13/2011. The necropsy showed lesions of hemorrhages with unclotted blood in many areas of the body. The submitted liver had a trace amount of diphacinone.

I023151

- 001 2011 Possible CA Urban Hawk (1) A Cooper’s hawk was found dead in a pool of blood on a sidewalk in Berkeley, CA. Toxicology testing detected brodifacoum and a trace amount of diphacinone.

I023850

- 001 2012 Highly probable NY N/R Squirrel (1) The New York State Department of Environmental Conservation on March 28, 2012 received a liver sample of a gray squirrel collected in Suffolk County, NY. Chemical analysis of the liver sample detected 841 ppb of diphacinone. The NY State Wildlife Pathologist concluded the gray squirrel was poisoned by the rodenticide diphacin one.

### Page 59 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

I023914

- 003 2012 Probable NY Urban Hawk (1) A red

- tailed hawk was submitted by the Urban Park Rangers after being found dead at a Manhattan intersection. The cranial portion of the oviduct was partly coated with clotted hemorrhage. The plumage behind the vent was stained with feces. Internally, there a small amount of clotted hemorrhage in the posterior abdomen. The crop contained bird tissue as did the stomach. There was a prolapse of the oviduct. An analysis of the liver

detected difethia lone (0.127 ppm), bromodiolone (0.068 ppm), diphacinone (0.059 ppm), and brodifacoum (0.046 ppm). The pathologist concluded that, "... the anticoagulant load... could have permitted rapid hemorrhage from blood vessels damaged by the prolapse, leading to s hock".

I024146

- 001 1994 Highly probable CA N/R Kangaroo rat (1) A Herman kangaroo rat was found ill near a bait box in Merced County, CA in 1994. Diphacinone levels in the liver of the exposed Herman kangaroo rat was 3.5 ppm.

This level is sufficient to indicate lethal non

- target

exposure.

I024152

- 004 2006 Highly

Probable CA N/R Coyote (1) In 2006 in Santa Cruz County, CA a laboratory staff reported that a coyote liver was submitted to the Pesticide Investigations Unit in order to analyze for anticoagulant residues. The liver contained four anticoagulants; chlorophacinone (1.13 ppb), coumatetralyl (0.10 ppb), diphacinone (1.50 ppb) and warfarin (0.060 ppb). It is highly likely that mortality was caused by exposure to anticoagulants.

### Page 60 of 60

INCIDENT

NUMBER YEAR CERTAINTY A STATE LAND USE GENERIC

SPECIES (Number

Individuals ) COMMENTS

I024152

- 009 2010 Highly probable CA N/R Feral p ig (1) The USDA staff contac ted the Pesticides Investigations Unit about mammary tissue from a pig that had large streaks of a black dye

- like material. The tissue was sent for analysis and it was confirmed that diphacinone was detected at 0.008 ppm.

I024154

- 012 2011 Possible CA N/R Owl(1) A great horned owl and a kestrel were submitted for necropsy and liver analysis. There was no necropsy information available in the report yet an analysis of the liver detected brodifacoum concentrations of 0.04 ppm in

the owl and trace amounts of diphacinone.

A: Certainty describes the level of certainty that exposure to the given pesticide was the cause or a significant contributi ng factor of the effects observed in the

incident.