Page 2 of 39 levels to aquatic invertebrates resulting from propoxur’s expected use as a spot treatment. However, this risk is limited to spot treatments wh ich occur nearby streams or water bodies. Please note that risk quotients (RQs) are not calculated consid ering that the applic ation rate is not specified on the labels. Therefore, the risk conclusions are supported based upon the threshold amount of propoxur used to induce a dverse impacts. The potential e xposure is then characterized by considering this threshold amount determined in context with its low ov erall usage. Although risks to aquatic organisms are possible to aquati c organisms within water bodies which are close to propoxur spot treatments, risks to terrestrial taxa are not indicated for the outdoor uses for

propoxur.

Given these conclusions, EFED has id entified the following uncertainties:

1.) The header language for two labels 1 includes terminology including perimeter treatments, and there is some ambiguity as to the scope of these perimeter treatments as indicated on the labels. For this preliminary ecologi cal risk assessment, as explained in Section 2.2, EFED assumed that such applications to bu ilding perimeters are spot treatments and not full perimeter applications. Clarification of this label language is important since full perimeter treatments can result in substantially greater application of pesticide and subsequent runoff to aquatic ecosystems.

2.) Protective language on the label to prevent propoxur outdoor s pot treatment applications close to the vicinity of streams and othe r water bodies is not explicit on eight labels 2 . As mentioned above, propoxur is ve ry toxic to aquatic organism s and it has the potential for exposure via runoff to water bodies located ne arby spot treatments. Otherwise, minimal exposure is expected with propoxur applica tion away from water bodies given the low amounts of propoxur historically used given the nature of s pot treatment applications.
Please refer to Sections 3.1 and 3.2 which provide a descripti on of the potential exposure based upon propoxur’s expected use as an outdoor spot treatment.

1 Including product Reg. nos. 84396-12 and 499-501.

2 Including product Reg. nos. 84396-12, 499-501, 655-546, 6218-24, 655-796, 82644-1Page 3 of 39 

# Environmental Fate and Ecological Risk Assessment for the Registration Review of Propoxur

2 – (1 – Methylethoxy) phenol methylcarbamate (Propoxur, CAS 000114-26-1)

P

repared by: Hannah Yingling, Biologist Gabe Rothman., Environmental Scientist U. S. Environmental Protection Agency Office of Pesticide Programs

E nvironmental Fate and Effects Division

E nvironmental Risk Branch IV 1200 Pennsylvania Ave., NW

M

ail Code 7507P Washington, DC 20460 R eviewed by: Al Vaughan, RAPL Keith Sappington,., Senior Biologist
José Meléndez , Chemist Mah Shamim, Branch ChiefPage 4 of 39 Table of Contents

1. Executive Summary ............................................................................................................. ... 5
1.1 Nature of Chemical Stressor ............................................................................................ 5

1.2 Potential Risks to Non-target Organisms ......................................................................... 5

1.3 Conclusions - Exposure Characterization ........................................................................ 6

1.4 Conclusions - Effects Characterization ............................................................................ 7

2. Problem Formulation ........................................................................................................... ... 8
2.1 Nature of the Chemical Stressor ....................................................................................... 8

2.2 Overview of Pesticide Usage ........................................................................................... 8

2.3. Environmental Fate and Tran sport Characterization ..................................................... 10

2.4. Ecological Toxicity Characterization ............................................................................. 13

2.5. Conclusions from Previous Risk Assessments............................................................... 17

2.6. Conceptual Model .......................................................................................................... 17

2.7. Analysis Plan ................................................................................................................. . 19
3. Risk Characterization ......................................................................................................... ... 21
3.1 Risk Estimation .............................................................................................................. 21
3.2 Risk Description ............................................................................................................. 26
3.3 Uncertainties, Limitations, and Data Gaps ..................................................................... 28

4. Federally Threatened and Endangere d (Listed) Species Concerns ....................................... 30

5. Endocrine Disruptor Screening Program .............................................................................. 31

6. References .................................................................................................................... ......... 33 Appendix A Qualitative Aquatic Exposure Modeling Summary ................................................ 36 Appendix B Endangered Species Assessment Information ......................................................... 38Page 5 of 39 

## 1. Executive Summary

1.1 Nature of Chemical Stressor

This document contains the environmental fa te, ecological risk, and endangered species assessments for the registered uses of propoxur (2 – (1 – Methylethoxy) phenol methylcarbamate).
This risk assessment is intended to address th e potential ecological risks associated with the registered uses of propoxur.

Propoxur was originally introduced in the Unite d States in 1959. It has 23 active Section 3 registrations. Propoxur is an N-methyl carbamate insecticide registered for indoor institutional, industrial, and commercial applications with very limited outdoor applicati ons. Propoxur is used to control a variety of pests including, cockroaches , ants, wasps, crickets, si lverfish, and other pest insects. There are 10 propoxur products registered with outdoor uses which include bait stations and liquid spray spot treatments to ant nests, cr acks and crevices, and part ial foundation treatments. Other propoxur outdoor uses include insecticide tape strips and patches, and formulations deployed in bait stations. The register ed use sites include food processi ng facilities, hotels, apartments, homes, and commercial/office buildings. There are no registered agricultural uses for propoxur. In addition, broadcast treatment s to lawns are not allowed.

Currently, propoxur is formulated as a pressurized spray for perimeter and liquid spot treatments, granules in bait stations, and impregnated residues within insecticide tape strip or patch products. Propoxur is mixed within a peanut butter-base in the granular form ulations contained within bait stations. Propoxur concentrati ons in end-use products ra nge from 0.25 to 10 % a.i.



### 1.2 Potential Risks to Non-target Organisms

The conceptual model for exposure only identifies the potential for exposur e to aquatic organisms to propoxur resulting from outdoor spot treatments and subsequent runoff to nearby water bodies. ( Section 2.6 ). EECs and RQs were not calculated in this assessment because standard exposure
scenarios have not been deve loped in EFED for outdoor spot treatments, and the maximum application rate is not specified on labels for this use. However, the potential for risk is evaluated by determining the threshold amount of propoxur necessary to induce adverse impacts. This threshold analysis accounts for runoff which may occur after propoxur spot treatments utilizing
PRZM/EXAMS. Minimum amounts of propoxur applied which re sults in adverse impacts are back-calculated from known toxicological information which exists for propoxur ( Section 3.1)

. The propensity for risks occurring for the amounts of propoxur applied which are determined to result in adverse impacts are discussed in Section 3.2. The potential for exposure resulting in adverse impacts only exists fo r direct effects to listed aqua tic species on an acute basis occurring due to propoxur hand-held spr ayer spot treatments around foundations. However, this risk is anticipated to be confin ed to areas where spot treatments occur close to streams or water bodies considering their discon tinuous nature of application. For remaining aquatic organisms, such as freshwater fish and estuarine/marine fish and invertebrates, all nonlisted aquatic species, and all li sted and non-listed terr estrial organisms, no risks of concern are identified from current propoxur uses including outdoor spot treatments.Page 6 of 39 Risk determinations by taxa for listed species are summarized in Table 1.1 below. A,“No Effect” risk determination for all listed species can be c oncluded for direct and indirect effects of propoxur use except for aquatic invertebrate s either as there is no comple te exposure pathway or adverse impacts are not expected. A “May Affect” determinati on is stipulated at this time for direct effects to aquatic inverteb rates resulting from propoxur spot treatm ent use close to streams since adverse impacts are possible. This determination may be clarified further in the future depending on
clarification of uncerta inties which currently exist regard ing propoxur spot treatments on product
labels.

Table 1.1. Potential Risks to Listed Taxa Asso ciated with Direct or Indirect Effects from the Currently Registered Uses of Propoxur.

Listed Taxon Direct Effects Indirect Effects

Terrestrial and semi-aquatic plants – monocots No Effect

Terrestrial and semi-aquatic plants – dicots No Effect

Birds No Effect
Terrestrial-phase amphibians and reptiles No Effect

Mammals No Effect

Terrestrial invertebrates No Effect
Aquatic nonvascular plants No Effect

Aquatic vascular plants No Effect

Freshwater fish No Effect
Aquatic-phase amphibians No Effect

Freshwater invertebrates May Affect* No Effect

Marine/estuarine fish No Effect

Marine/estuarine invertebrates No Effect
*Determination based on direct effects to listed species on an acute basis, only possible resulting from propoxur outdoor spot treatments using hand held sprayers applied to foundations which occur close to streams and water
bodies. This determination may be clarified further in the fu ture depending on clarification of uncertainties which currently exist regarding propo xur spot treatments which currently exist on product labels.



### 1.3 Conclusions - Exposure Characterization

There is the potential for runoff of propoxur to a quatic environments mainly associated with its topical application in outdoor spot treatments occurring ar ound the foundations of buildings, cracks and crevices, and ant nests ( Section 2.6 ). Propoxur’s high mobility and high persistence suggest this route of ex posure is possible ( Section 2.3 ). However, aquatic e xposure is likely to be reduced by the discontinuous, non-broa dcast nature of spot treatment applications. Furthermore, the current use volume of propoxur is rela tively limited based on nationwide data ( Section 2.2 ). Any exposure in the aquatic envi ronment is most likely limited to outdoor spot treatments that
occur close to streams and othe r water bodies. Propoxur spot treatments occurring away from water bodies is expected to result in negligible exposur e (i.e., well below t oxicologically-relevant levels) based on its small applica tion rate coupled with its disper sion within runoff during transport
to water bodies.Page 7 of 39 Exposure in terrestrial habitats is not expected since propoxur is not expected to be bioavailable to birds, mammals, or non-target terr estrial invertebrates in bait sta tions, nor are the insecticide tape strips or impregnated tag products of propoxur exp ected to serve as attractive food sources birds and mammals. Furthermore, non-targ et terrestrial invertebrates are not expected to be attracted to these propoxur products. Crack and crevice and spot treatments are not expected to overlap with potential food sources of birds and mammals. The only possible exception is the case for birds and mammals eating dead ants that are treated with pr opoxur. However, only limited exposure is expected given propoxur’s low use. Therefore, no risk for terrestrial organisms and plants are identified based on the lack of a complete expos ure pathway or limited exposure due to low use.
Please refer to Section 2.6 for further discussions on the rati onale behind these findings for each propoxur outdoor use.



### 1.4 Conclusions - Effects Characterization

Acceptable toxicity studies for propoxur include an acute freshwater fish, acute freshwater daphnid, avian acute oral and an acute contact honeybee study. Supplem ental studies include acute estuarine/marine fish, acute estuarine/ma rine invertebrate, avian subacute dietary, and avian reproduction.

Aquatic Organisms

Technical grade propoxur is classified as moderately toxic to fish (which serve as surrogates for aquatic-phase amphibians in the absence of amphibian toxicity da ta). The 96-hr LC 50 for Rainbow trout ( Oncorhynchus mykiss ) was determined to be 3.7 mg/L (MRID 00149171). Propoxur is very highly toxic to aquatic inve rtebrates based on a 48-hr EC 50 of 0.011 mg/L for the water flea, Daphnia magna (MRID 00149172).

Supplemental data for qualitative us e only is available for freshwater invertebrate life cycle, acute estuarine/marine fish, and acute estuarine/marine invertebrates showing propoxur to be slightly toxic, moderately toxic to estuarine/marine fish and invertebrates. No toxicity data are on the chronic toxicity of propoxur to fr eshwater fish, freshwat er invertebrates, estuarine/marine fish,
estuarine/marine invertebrates.

Terrestrial Organisms

Propoxur is highly toxic to bird on an acute basis. The 96-hr LD 50 for the bait formulation is 23 mg/kg a.i. (MRID 41625101). Technical grade pr opoxur is classified as highly toxic to
terrestrial invertebrates. In an acute contact oral study for the honeybee ( Apis mellifera ) the endpoint was determined to be 1.35 μ g/bee (MRID 00036935). An acute oral study conducted using a rat shows propoxur to be moderately to xic to mammals with an endpoint of 68 mg/kg (MRID00152443).

Supplemental data for qualitative use only are av ailable for avian dietar y, avian reproduction, andPage 8 of 39 mammalian reproduction showing propoxur to be highl y toxic to avian species and moderately
toxic to mammals. No data are available for terrestrial plants.



## 2. Problem Formulation

2.1 Nature of the Chemical Stressor

Propoxur is an N-methyl carbamate non-systemic inse cticide that is used to control a variety of pests including cockroaches, ants , wasps, crickets, silverfish, a nd other pest insects. Propoxur interferes with acetylcholinesterase, an essential enzyme in the transmission of signals in nerve cells. Exposure to propoxur results in the over-ex citation of the nervous system and eventually death in fleas, ticks and othe r insects (American Conference of Governmental Industrial Hygienists, 2010). There are no longer any agri cultural uses registered for propoxur, and the majority of current uses are limited to indoor applications.



### 2.2 Overview of Pesticide Usage

There are a total of 23 active registrations with propoxur with 10 active registered products containing outdoor uses. Outdoor uses of propoxur are applied as a spray or placed within bait stations, insecticide tags, or tape strips anywhere an infestation of target insects are observed. Propoxur spray products and bait statio ns are used outside of homes, apartments, office complexes, food processing facilities, and hotel s. Propoxur insecticide tags or tape strips are used primarily on or around telecommunications utility lines, transf ormers, and circuit boxes. Previous broadcast granular bait application uses have been discontinued.

Some of the registered spray products for ou tdoor use contain propoxur as the single active ingredient (1 percent a.i.) with petroleum distilla tes composing the remainder of the solutions. The remainder of the spray propoxur products are co -formulated with MGK 264, pyrethrins, and piperonyl butoxide, all composing of 1 percent pr opoxur. Propoxur is the single active ingredient in the bait (within bait stations, 0.25 percent a.i. ) and impregnated formulations (within insecticide tags and tape strips, 9.4 and 10 percent a.i., respectively). The products types and formulations of propoxur used outdoors are listed in Table 2.1 below. It should be noted that maximum application rates, maximum retreatment intervals, or time between treatments are not specified on the labels.

Table 2.1. Description of propoxur products used outdoors.

Use Description Product Photo Formulation Description % a.i. Propoxur
Product Density a Spot Treatment –
Ant Nests Pressurized

spray (397 grams of product) 1 0.065 lbs./gallon Crack and Crevice

Treatment
Foundation

Treatment Ready-to-Use
SolutionPage 9 of 39 Table 2.1. Description of propoxur products used outdoors.

Use Description Product Photo Formulation Description % a.i. Propoxur
Product Density a (55 gallons of product)

Insecticide Tag Impregnated
Material 9.4 1.65 x 10 -3 lbs./tag

Insecticide Tape Strip 10 1.96 x 10 -3 lbs./strip

Bait Station Granules 0.25 2.59 x 10 -5

lbs./bait station

a Derived from information on labels, and calculated according to following for each product type:

Insecticide tag (From Reg. No. 13283-26 product label): Pr oduct net weight (8.0 g) x Conversion Factor (lb ) 453.6 g x Percent a.i. (9.4%)

Insecticide tape (From Reg. No. 8730-49 product label): Product net weight (8.9 g) x Conversion Factor (lb ) 453.6 g x Percent a.i. (10%)

Bait Station (From Reg. No. 9688-305 product label): Product net weight (4.7 g) x Conversion Factor (lb ) 453.6 g x Percent a.i. (0.25%)

Sprays (From Reg. Number 279-3995 Product Label): [Product net weight (397 g)/Volume of product solution (0.134 gallons, calculated below)] x Percent a.i. (1 %).

Where volume of product solution = Product net weight (397 g) x Reciprocal of the Product Solution Density ( mL, MRID No. 45233701) x Conversion Factor ( L ) x Conversion Factor (gal) 0.787g 1,000 mL 3.79 L

The scope of outdoor uses for propoxur is very limited. First, propoxur is used outdoors within bait stations in two products (R eg. Nos. 9688-305 and 1663-32). Se cond, it is also used as an impregnated material on insecticide tags (Re g. No. 13283-26) and insecticide tape (Reg. No. 8730-49). Third, propoxur is used as liquid spra y spot treatments to ant nests, cracks and crevices (Reg Nos. 655-546, 6218-24, 655-796, 82644-1, 84396-12, 499-501) from spray cans or hand-held sprayers. Propoxur is also used for foundation treatments. The headers on two labels (Reg. Nos. 84396-12 and 499-501) indicate that propoxur can be used around perimeters on buildings. Although this labeled use is ambiguous, it does not appear that the intended use of propoxur is for traditional perimeter treatments which completely surround the building. The
reasons are stated below:

1.) The label instructions on one label (Reg. No. 84396-12) suggests that propoxur use isPage 10 of 39 limited to small areas where insects are observed (e.g ., Spray thoroughly those areas where pests have been seen or found includ ing outside surfaces of screens, doors, window frames, foundations, patios, or other pl aces where insects may enter. For ants, spray runways. Repeat as necessary. Do not spray vegetation. Do not apply as a landscape treatment (to lawns, shrubs or trees, or plants ).

2.) The propoxur uses are either available as rea dy-to use solutions contained in pressurized sprays or a hand-held sprayers . Both types of products are manually applied to small

areas.

3.) The label instructions do not mention any continuous treatment such as banded treatments along foundations.

There are several indications that the overall propoxur use is very limited. First, usage data provided to the Biological and Ec onomic Analysis Division (BEAD) of the Office of Pesticide Programs for propoxur indicates th at it is a minor use chemical in the professional pest management sector, accounting for <1% of the to tal chemicals applied each year (8,000 and 9,000 lbs applied in 2001 and 2003, respectively). In more recent years, usage data suggests that limited use of propoxur continues. Commercial databases show that there is only 200 – 300 lbs. of propoxur bait station products ava ilable nationwide in the consum er market (Proprietary Data, 2012). In addition, CALPUR reports that less than 1 pound of propoxur has been applied for outdoor spot treatments in 2012 throughout Californi a where spot treatments and residential uses of insecticides are known to be prevalent 3 . This limited use of pr opoxur further suggests that continuous perimeter treatments do not exist and that organized community use of propoxur is not prevalent.



### 2.3. Environmental Fate and Transport Characterization

In its natural form, propoxur is a colorless crys talline solid with a melting point of 81°C (Berg, G.L. 1986). It is relatively soluble in water (Ber g, G.L. 1986) and stable in acidic environments, but highly unstable in alkaline environments. Propoxur is moderately volatile from dry surfaces. However its vapor pressure of 6.5 x 10 -6 torr suggests that large amounts of propoxur are not expected to volatilize at a fast rate (Worthing C.R., 1983). Th e physicochemical characteristics associated with propoxur are summarized in Table 2.2

.

3 Accessible on-line at: http://www.cdpr. ca.gov/docs/pur/pur12rep/chmrpt12.pdfPage 11 of 39 Table 2.2. Physicochemical properties of propoxur.

Parameter Value Citation

Structure PubChem Sketcher 4

Molecular formula C 11 H 15 NO 3 MRID 151791 Molecular weight 209.25 g/mol MRID 151791 CAS Number: 114-26-1 EpiSuite

CAS Name: Phenol, 2-(1-methylethoxy)-, methylcarbamate EpiSuite

Water solubility 1,750 mg/L at 20°C 1,974 mg/L at 25°C Berg, S.L., 1983 EpiSuite, WSKOW v.1.42 Vapor pressure 6.5 x 10 -6 torr @ 25°C Worthing C.R., 1983 Henry’s law constant 3.35 x 10 -9 atm-m 3 /mol @ 25°C EpiSuite, HENRYWIN v. 3.20 Octanol-water partition coefficient (log K
ow ) 1.90 EpiSuite, KOWWIN v.1.68

Bioconcentration f actor (BCF) in
fish 4.68 L/kg EpiSuite, BCFBAF v.3.01

In soil where propoxur spot treatmen ts can occur, propoxur appears to be relatively persistent with half-lives generally ranging be tween 80 – 210 days in aerobic and anaerobic soils (MRID No. 085768). Propoxur mainly degrades to carbon dioxid e under aerobic conditions. Under anaerobic conditions, propoxur degradation most likely occurred due to hydrolysis as degradation in sterile samples were equivalent to non-sterile samples.

In water, propoxur is stable under neutral to acid ic conditions, but degrad ation appears to occur mainly under alkaline conditions. Propoxur hydrolyzes with a half-life of 16 days at pH 8 to as rapidly as approximately 4 hours at pH 10. Hydrolysis results in breaking the carbamate linkage (MRID No. 085762). Propoxur demons trates some photodegradation under exposure to weak irradiation relative to natural light with a photol ysis half-life of 13 da ys. Propoxur was found to mainly degrade to carbon dioxide in the hydrolys is and aqueous photolysis studies. However, some levels of the isopropoxy phenol degradate wa s detected up to 24.3 percent of the applied radioactivity in the aq ueous photolysis study.

Propoxur appears to be mobile to highly m obile (per FAO classification) with K oc values ranging between 3.4 – 11.2 mL/g-oc in sandy loam and silt loam so ils, respectively. Propoxur is moderately mobile in si lty clay soil with a K oc value of 102.6 mL/g-oc de termined in the study (MRID No. 085770). Propoxur’s overall relative high mobility is evident in a column leaching study in which propoxur was applied to 12-inch so il columns. Leachate material accounted for between 69 to 74 percent of the applied radioa ctivity after 45 days (MRID No. 085769). Ten supplemental terrestrial field dissipation studies with propoxur applied to soil plots further provide evidence of propoxur’s highly mob ile characteristics. These fiel d dissipation studies roughly show

4 Accessible on-line at: http://pubchem.ncbi.nlm.nih.gov/edit2/index.htmlPage 12 of 39 that propoxur moves rapidly thr ough the soil below a 12 inch sa mpling depth (MRID No. 085772).

If spot treatments are applied close enough to water bodies, propoxur’s environmental fate and behavior parameters indicate that propoxur re sidues may easily move to those water bodies through soil and runoff given its high m obility and persistence in soil. Table 2.3 shows the details of each fate and transport study for propoxur. Many of the environmental fate and transport studies available for propoxur have been submitted to the EPA as guideline studies. The study
classifications and notes on st udy quality are provided in Table 2.3 below.

Table 2.3 Summary of environmental fate a nd transport studies and parameter values for propoxur.

Study (Guideline Nos.) Value and unit Major Degradates MRID
# or
Citation Study Classification,
Comment

Abiotic Hydrolysis

(835.2120) t 1⁄2 = Stable (pH <7)

t 1⁄2 = 16 days (pH 8)

t 1⁄2 = 1.6 days (pH 9)

t 1⁄2 = 0.17 days (pH 10) None determined 085762 Supplemental

-Degradates not

analyzed

Aqueous Photolysis

(835.2240) t 1⁄2 = 13 days - Carbon Dioxide (30.9%, 21 days)

- Isopropoxy phenol (24.3 % AR, 21 days) 085763 Acceptable

- Half-life adjusted for hydrolysis

- Irradiation approximately
18% of natural sunlight during
summertime in Kansas City,

MO

Soil Photolysis

(835.2410) Sandy loam soil (pH 8.2)

t 1/2 = 77 days - Unextracted
Residues (12 % AR, 28 days)

- Volatiles (10% AR, 28 days) 085765 Acceptable

- Irradiation approximately
18% of natural sunlight during
summertime in Kansas City,

MO

Aerobic Soil
Metabolism

(835.4100) Silt loam soil (pH 6.4)

t 1/2 = 80 days

Sandy loam soil (pH 5.7)

t 1/2 =210 days - Carbon Dioxide (35%, 336 days)

- Unextracted
Residues 085768 Supplemental

- Complete

formation and
decline ofPage 13 of 39 Table 2.3 Summary of environmental fate a nd transport studies and parameter values for propoxur.

Study (Guideline Nos.) Value and unit Major Degradates MRID
# or
Citation Study Classification,
Comment
(40%, 336 days) degradates
could not be
resolved in 336- day study

Anaerobic Soil

Metabolism

(835.4200) Silt loam soil (pH 6.4)

t 1/2 = 80 days

Sandy loam soil (pH 5.7)

t 1/2 =108 days - 085768 Supplemental

- Degradation
rate identical
in sterile

versus nonsterile samples; hydrolysis most likely
observed.

- Complete
formation and
decline of degradates
could not be
resolved in 336-day study

Mobility, unaged leaching, adsorption/ desorption and aged leaching soil
column

(835.1230) Sandy Loam Soil

K
oc = 3.4 mL/g
OM = 2.8%

Silt Loam Soil

K
oc = 11.2 mL/g
OM = 5.1%

Silty Clay Soil

K
oc = 102.6 mL/g
OM = 0.5% N/A 085770 Acceptable

AR = Applied radioactivity. N/A means not applicable.

Bioaccumulation of propoxur is not expected in fi sh or aquatic organisms due to its low Log K ow value of 1.90 (K ow = 79).



### 2.4. Ecological Toxicity Characterization

In screening-level ecological risk assessments, effects characterization describes the types of effects a pesticide can have on aquatic and terrestrial organisms. In absence of toxicity data, birds are used as surrogates for reptiles and terrestria l-phase amphibians and freshwater fish are used asPage 14 of 39 surrogates for aquatic-phase amphi bians. This characterizatio n is based on the registrantsubmitted toxicity data for birds, mammals, fresh water fish, aquatic invertebrates and aquatic plants.

The assessment also evaluates the potential for propoxur to directly or indirectly affect listed species or modify designated critical habitat. Assessment endpoints ma y include direct toxic effects on the survival, reproduction, and growth of lis ted entities, as well as indirect effects, such as reduction of the prey base or modification of habitat.

The most sensitive endpoint for each taxon is us ed for risk estimation, which in the case of propoxur is from a single study for each taxon. T oxicity data were available for 5 taxonomic groups including freshwater fish, estuarine/marine fish, estuarine/ marine invertebrates, birds and
mammals. Tables 2.4 and 2.5 provides a summary of the ta xonomic groups, surrogate species tested, and results of studies to characterize th e potential acute ecological effects of propoxur (no chronic toxicity studies are available).

The ecological effects characterization for pr opoxur is based upon registrant-submitted toxicity
data. Tables 2.4 and 2.5 lists these studies and their review cl assifications. Ecotoxicity data for propoxur was reviewed in a Prel iminary Problem Formulation fo r Registration Review (USEPA 2009, DP365168). These data are summarized briefly in the following sections.

Aquatic Organisms

Technical grade propoxur is classified as moderately toxic to fish (which serve as surrogates for aquatic-phase amphibians) and very highly toxic to freshwater invert ebrates. No chronic toxicity
data were available for freshwater and estuarine/ marine fish, freshwater and estuarine/marine
invertebrates. No data was available for vasc ular and one supplemental study was available for non-vascular aquatic plants. A summary of the mo st sensitive aquatic toxicity data for propoxur, based on a current Agency review of all submitted data is provided in Table 2.4.

The freshwater invertebrate 21-d life cycle toxicity test (MRID 41425301) was classified as supplemental due to a lack of reporting on a numbe r of factors including health and history of organisms at start of testing, volume of test solution and load ing factor, total organic carbon, length, bodyweight, and number of offspring per female. Given that a quantitative assessment was not conducted, the value of quantitative use of th e reported endpoints in the study were not
evaluated at this time.

The estuarine/marine invertebrate acute toxi city test (MRID 40228401), es tuarine/marine acute fish study (MRID 40228401), and algal growth inhi bition test (MRID 00158414) were considered scientifically sound but were classified as suppl emental because the test duration and other study features deviated from EPA guidelines and t hus did not satisfy the requirement for data.Page 15 of 39 Table 2.4. Most sensitive aquatic species ev aluated for assessing potential ecological effects of propoxur.

Study Type Tested Species Purity of

Test
Substance Toxicity Endpoint Study MRID and Toxicity Classification

96-Hour Acute
Freshwater Fish Rainbow trout ( Oncorhynchus mykiss ) 98.8 LC 50 = 3.7 mg/L 00149171 Moderately Toxic Acceptable

Freshwater Fish Early Life Stage No data

48-hr Acute
Freshwater
Invertebrate Waterflea (Daphnia magna) 98.8 EC 50 = 0.011 mg/L 00149172 Very Highly Toxic Acceptable

Freshwater
Invertebrate 21-d Life Cycle Waterflea ( Daphnia magna) 98.5 N/A 41425301 Supplemental

48-hour Acute
Estuarine/Marine
Fish Sheepshead
Minnow ( Cyprinodon variegatus ) 100 LC 50 >1 mg/L 40228401 Moderately Toxic Supplemental

Estuarine Marine Fish Early Life Stage No Data

96-hour Acute
Estuarine/Marine
Invertebrate Pink Shrimp (Penaeus duorarum) 100 LC 50 = 0.041 mg/L 40228401 Moderately Toxic Supplemental

Estuarine/Marine
Invertebrate Life Cycle No data

Aquatic Plants Green Algae 99.6 EC 50 = 5.3 mg/L 00158414 Supplemental

Vascular and
Nonvascular Plants No data

1 Freshwater fish are considered su rrogates for aquatic-phase amphibians.

Terrestrial Organisms

Propoxur is highly toxic to the Bobw hite quail on an acute basis wh en exposed to the formulated product. Table 4 in the 2009 Problem Formul ation (DP365168) cites The Handbook of Toxicity of Pesticides to Wildlife, pub lished in 1984, as a source of a nu mber of avian endpoints more sensitive than the bobwhite qua il (00160000, Hudson et al.). The mo st sensitive endpoint listed
within the Handbook is LD 50 =3.55 mg ai/kg for the House Finch; while there are more sensitive endpoints available within the doc ument, and the studies are cons idered to be scientifically sound, they are classified as supplemental becau se the methods, duration and standards of the study differ than those listed in our current guidelines. For this reason, the most sensitive endpoint considered in this assessment is that associated with the registrant submitted avian acute oral study (MRID 41625101).

The avian 5-day dietary study is classified as supplemental because methods, duration and standards of the study differ than those listed in ou r current guidelines but are still considered to be scientifically sound. There are a number of additional avia n subacute endpoints availablePage 16 of 39 conducted using different spec ies; these can be found under MRID 00022923 within Table 4 of
the 2009 Problem Formulation.

In addition to the avian reproduction study conducted using the bobwhite list ed below, there is a study available conducted usi ng a mallard (MRID 00149016). The study showed reduced egg reproduction and embryo viability at 80 ppm; however the study was classified as supplemental because raw data was not provided to allowed statis tical verification of the results. Therefore, the study conducted using the bobwhite was cited as the most sensitive endpoint, despite the inability to establish a NOEC for reproductive effects. The NOEC for brain cholinesterase inhibition was found to be 80 ppm.

Data are available for acute toxicity to mammal s, showing propoxur is moderately toxic to the laboratory rat. No chronic da ta are available for mammals. An acceptable study shows that propoxur is highly toxic to honeybe es on an acute contact basis

. Toxicity data on the effects of propoxur on terrestrial pl ants are not available

. A summary of the most sensitive terrestrial toxicity data for propoxur, based on a current Agency review of all submitted data is provided in
Table 2.5

Table 2.5. Most sensitive terrestrial species evaluated for assessin g potential ecological effects of propoxur.
Study Type Tested Species Percent a.i. Toxicity Endpoint Study MRID and Toxicity Classification

Acute Avian Oral Bobwhite quail ( Colinus virginianus) 2 (Formulated product—bait) LD 50 = 23 mg a.i./kgbw 41625101 Highly toxic Acceptable

Avian 5-d Dietary Bobwhite quail ( Colinus virginianus) Technical %
unknown LC 50 = 206 mg/L 00022923 Supplemental *

Avian Reproduction Bobwhite quail ( Colinus virginianus ) 98 NOAEC =320 mg/L (highest dose; NOEC for reproductive effects not established) 00149017 Supplemental

Acute Mammalian
Oral Laboratory rat ( Rattus norvegicus ) Technical LD 50 = 68 mg/kg -bw (F) 94 mg/kg-bw (M) 00152443 Moderately toxic

Mammalian
Chronic—2 generation reproduction Laboratory rat ( Rattus norvegicus ) 99.8 NOAEC = 80 ppm 42615403 No reproductive toxicity observed at levels up to 80 ppm in diet

Terrestrial
Invertebrates acute

contact Honeybee ( Apis mellifera ) Technical LD 50 = 1.35 μ g/bee 00036935 Highly Toxic Acceptable

Terrestrial Plants No Data

* Although classified as supplemental, the USDI data are derived from scientifically sound studies. Although the actual % ai was not reported, it is assumed to be greater than 95%

Degradate toxicityPage 17 of 39 The existing collection of environmental biodegra dation laboratory studies indicate that propoxur degrades mainly to carbon dioxide in soil and water under environmentally relevant conditions. Since carbon dioxide is considered benign in comparison to propoxur, this risk assessment will focus on propoxur as the main stressor of concern. 5

ECOTOX Open Literature

Literature identified in search of the publically available ECOTOX databa se did not result in
identification of listed e ndpoints that were toxicologically rele vant or more sensitive than those found in registrant submitted studies. There ar e endpoints available for estuarine/marine
invertebrates that are considered to be virtually identical to those found in registrant submitted
studies.



### 2.5. Conclusions from Previous Risk Assessments

The ecological risk assessment included in th e propoxur RED was based on laboratory fate and ecotoxicological data submitted by the registrant in support of reregistration, data in publicly available literature, and incident reports of adverse eff ects on non-target organi sms associated with the use of propoxur. The previous ecological risk assessments consid ered the parent chemical only as the stressor of concern. The primary enviro nmental concerns identified in the 1996 RED were
acute risks to birds and mammals based on broad cast granular bait applications. EFED did not
have the tools with which to a ssess chronic risk to birds or ma mmals based on the granular bait application. Therefore, chronic risk to either birds or mammals was not assessed. Regardless, broadcast granular bait applications of propoxur have been cancelled.

Based on the RED risk assessment, a number of mitigation measures were suggested for consideration to address risks. The only measur e relevant to current us es of propoxur proposed
included to limit outdoor uses to crack and cr evice treatment considering registrants have previously indicated in the Phase 3 Response that this is the main way the product is applied outdoors. However, labels allowing for broader spot treatment uses such as those around structure
foundations and to ant ne sts still exit today.



### 2.6. Conceptual Model

Outdoor uses of propoxur include spot treatment s, bait station uses, insecticide tags, and insecticide tape strips. Descript ions of the relevance of potential risk to terrestrial and aquatic organisms are discussed below for each use:

 Bait Stations: Target pests for propoxur bait station uses include ants and roaches. Bait stations contain granular form s of propoxur enclosed within them. The bait stations have opening indentations on its side where thes e target insects can enter to access the

5 Isoproxy phenol was detected in aqueous photolysis study. The formation of this degradate is not expected to be prevalent in the environment since aqueous photolysis is not expected to be an important degradation pathway in water bodies which may exist nearby propoxur treated areas.Page 18 of 39 propoxur bait. There are dimensions of 0.5 inch by 0.25 inch openings in the design for
each bait station. Please refer to Table 2.1 for a side-view photograph of the bait station.

Given the containment of propoxur within ba it stations, exposure is not expected for aquatic or terrestrial organisms. Propoxur in bait stations is not expected to be
translocated to water bodies. Therefore risk for bait station uses to aquatic organisms is not expected

.

For non-target terrestrial organisms, exposure to propoxur in bait stations is not expected. Non-target terrestrial invert ebrates are not expected to be impacted from propoxur bait
stations since the small dimensions of the openings prohibit these insects from entering, restricting the bioavaila bility of propoxur to these organisms. The same reasoning would apply to mammals and birds. Therefore, risk associated with bait station uses to terrestrial organisms is not expected.

 Insecticide Tags and Insecticide Tape Strips: These products compose of padded material impregnated with propoxur. Use of th ese products are restri cted to placement on or around telecommunications utility line s, transformers, and circuit boxes.

Since electrical equipment is located in dry places to prevent electrocution problems associated with water interaction, propoxur fr om these products is not expected to wash off into water, preventing exposure to aquatic environments from occurring. Therefore, risk for these uses to aquatic organisms is not expected.

In addition, use of these products are not e xpected to attract n on-target terrestrial invertebrates, birds, or mammals. Furthermor e, these products are not likely to result in any habitat modification for terrestrial orga nisms as propoxur use is restricted only to
around electrical facilities. Therefore, risk for these uses to terrestrial organisms is not expected.

 Spot Treatments: Propoxur is applied around crack a nd crevices, to ant nests, and around foundations in spot treatments. Propoxur is not applied in br oadcast applications and is not allowed to be applied to lawns.

Propoxur spot treatments to cracks and cr evices, around foundations, and ant nests are not expected to be applied to surfaces woul d serve as food sources for birds or mammals. In addition, propoxur is not direct ly applied to flowering plan ts nor is substantial spray drift expected to occur to off-target plants from spot treatment applications. Also, it is not expected to be expected to be uptaken by these plants since it is a non-systemic
insecticide 6 . However, exposure is plausible as mammals and birds can eat dead ants which are covered with propoxur residues duri ng spot treatment. However, considering propoxur’s very low use, large amounts of dead ants covered with propoxur are not expected to be present over wide area s for birds and mammals to consume. Therefore, risk is not anticipated for terrestrial organisms from propoxur spot treatments.

6 Citation: http://pmep.cce.cornell.edu/ profiles/extoxnet/metiram-p ropoxur/prop oxur-ext.htmlPage 19 of 39 Since spot treatments of propoxur are applied directly to ant nest s or around foundations outdoors, aquatic exposure may result from tr anslocation of propoxur residues to water bodies via runoff. However, only a small fr action of propoxur applie d is expected to runoff since it is not used in high quantities, no r is it used in broad cast applications. In addition, propoxur is most likely to runoff to water particularly wher e applications occur
close to water bodies. Therefore, considering the potential for a small amount of exposure and high toxicity for propoxur to aquatic organisms (see Section 4.1), there is a potential for risk to aquatic organisms, which this risk assessment will address.

Table 2.6 below summarizes the findings addressi ng the conceptual model for this propoxur ecological risk assessment. In summary, exposure to terrestrial organisms is not expected for all outdoor propoxur applications. Exposure to aquatic organisms is not expected for propoxur bait station, insecticide tag, and insec ticide tape uses. However, ther e is potential ri sk to aquatic organisms associated with pr opoxur outdoor spot treatments.

Table 2.6. Conceptual model findings for identi fication of potentia l risk for ecological risk assessment associated with propoxur outdoor uses.

Outdoor Uses Terrestrial Risk? Aquatic Risk?
Bait Stations No – no exposure Insecticide Tags and Tape No – no exposure Spot Treatments (Cracks and Crevices, Foundations, Ant Nests) No – dietary exposure
scenario from dead ants negligible Possible – small exposure possible

Consistent with the findings presented in Table 5.1 , the following ecological risk hypothesis is being employed for this ecological risk assessment:

Based on the application methods and availabl e toxicity data for non-target aquatic species, propoxur has the potential to reduce survival, reproduction, and/or growth in nontarget freshwater fish, estuarine/marine fish, aquatic invertebr ates, and aquatic plants when used for outdoor spot treatments in a ccordance with the curre nt labels. These nontarget organisms include federally listed threatened and endangered species as well as non-listed species.



### 2.7. Analysis PlanPage 20 of 39 In order to address the risk hypothesis, the pot ential for adverse effect s from propoxur outdoor spot treatments on the environment is evaluated. However, since there is no standard scenario established to evaluate outdoor spot treatment applications and very limited information on maximum application rates on the labels, this risk assessment will not rely on risk quotients (RQs) for the determination of risk as in traditional risk assessments. Rather, a threshold analysis relating the exposure necessary to induce adverse impacts w ill be used to describe the potential exposure that exists for aquatic organisms based on its expected use as a spot treatment. The use of environmental fate, and ecological effects will be in tegrated together in order to characterize the potential exposure. The parent compound, propoxur, is the toxicant that will be assessed. Besides propoxur, carbon dioxide is the only other compound that has been detectedin environmentallyrelevant laboratory environmental fate studies.

First, the risk hypothesis, provided at the end of Section 2.6 , will be tested in a Preliminary Adverse Impacts Analysis by calculating the critical amount of propoxur (by mass and volume) which is necessary to induce potential adverse imp acts to listed and non-listed aquatic organisms. This information is directly determined from the most sensitive aquatic sp ecies endpoint. Please
refer to Section 3.1 for further details. This critical am ount will then be compared to the amount of parcels for propoxur products ( e.g. , number of spray cans) in orde r to relate the critical mass causing adverse impacts to aquatic taxa in water bodies to an amount of propoxur that is inside a spray can. In this way, the critical mass of propoxur causing a dverse impacts is placed into perspective with the amount of propoxur potentially app lied from a parcel, and therefore, the
likelihood for the critical mass ever entering a water body can be described.

The propensity of the critical amount of propoxur causing adverse impacts via direct entry into a water body, as determined from the Preliminary Adverse Impacts Analysis above, will be further
evaluated in a Refined Adverse Impacts Analysis . In this analysis, the threshold application amount of propoxur causing adverse impacts to list ed and non-listed aquatic species will be further examined by considering propoxur’s overall poten tial to reach water bodies via runoff at toxicologically-relevant concentrations. The fate and transport properties of propoxur, soil properties, and variabilit y in rainfall will be factors accounte d for in this analysis. The most sensitive endpoint for aquatic species along w ith propoxur density w ithin products (0.065 lbs./gallon), volume of the water body (20,000 m 3 farm pond), and estimated exposure concentration (EECs) which are based on a first-guess application rate (1 kg a.i./ha) will all be used determine this critical applicati on amount for propoxur . Please refer to Section 3.1 for further details on the back-calculation approach to determine the amount of gallons necessary for propoxur to induce adverse impacts. EECs normalized to the first-guess application rate will be calculated using the Pesticide R oot Zone Model coupled with the Exposure Analysis Modeling System model (PRZM/EXAMS). Finally, the critical amount of propoxur to induce adverse effects to listed and non-listed sp ecies determined in the Refined Adverse Impacts Analysis will be put into context considering the likely us e patterns of propoxur cons idering its limited use outdoors as a spot treatment. This discussion is included in Section 3.2

.

Considering the lack of expected bioavailability and limited scope of use sites for propoxur spot treatments, exposure to non-target terrestrial or ganisms and plants is presumed negligible ( Section
2.6 ) and will not be estimated.Page 21 of 39 

## 3. Risk Characterization

3.1 Risk Estimation

Since maximum application rate s are not specified on the labe ls for propoxur outdoor spot treatments, threshold levels of exposure and product application (by mass and volume) that induce adverse impacts are determined. First, a Preliminary Adverse Impacts analysis evaluating the amount of propoxur necessary to tr igger adverse impacts to aquatic organisms based upon its direct entry into a wate r body is first considered. Then, a Refined Adverse Impacts Analysis will be conducted to show how runoff occurring after propoxur spot treatments can impact the adverse impacts application thre shold level of propoxur impacting water bodies. The preliminary and refined threshold analyses for acute listed aquatic species are described below. The results for threshold propoxur amounts resulting in adverse im pacts for acute listed aquatic species and acute non-listed aquatic species are shown in Tables 3.1 and 3.2 for the preliminary and refined analyses, respectivel y. Due to a lack of scientifically-sound toxicological data, chronic exposure is not considered. Please refer to Section 3.3 for further characterization for chronic exposure.

Preliminary Adverse Impacts Analysis

As mentioned in Section 2.6 , the first test of the risk hypothe sis for aquatic exposure associated with propoxur spot treatments will involve calcul ating the critical mass of propoxur necessary to induce adverse impacts to aquatic organisms. This calculation will be solely based on the most sensitive acute endpoint resulting from effects to a quatic invertebrates. Th e endpoint used is for
the daphnid EC 50 = 0.011 mg/L (MRID No. 0149172). Based on this endpoint, 11 grams of propoxur or 0.373 gallons of product will result in adverse impacts to listed species assuming it enters a water body. This cr itical mass of propoxur is determined from the following
calculations:

Acute Concentration of Concer n (COC) in Water Body = Endpoi nt (0.011 mg/L) x 0.05 (Acute Level of Concern or LOC) = 5.5 x 10 -4 mg/L = 5.5 x 10 -4 mg/L

Water Body Propoxur Mass Influx Tri ggering LOC = Acute COC (5.5 x 10 -4 mg/L) x Conversion Factor (1,000 L/m 3 ) x Conversion Factor (grams/ 1,000 mg) x Volume of Standard Pond (20,000 m 3 ) = 11 grams of propoxur

Equivalent Product Amount Triggering LOC = Mass of propoxur cau sing adverse impacts (11 grams) x Reciprocal of Propoxur Product Density (gallon/0.065 lbs from Table 2.1 ) x Conversion Factor (lbs./453.6 grams) = 0.373 gallons of product

This 11 gram critical mass of propoxur triggering the LOC for aquatic taxa can be placed into context with a spray can contai ning propoxur that is currently us ed. Based on spray cans ofPage 22 of 39 propoxur containing 397 grams of solution (from Reg. No. 279- 3995 product label), the amount of solution that would trigger the LOC for liste d aquatic invertebrates is an equivalent of 2.77

spray cans . The calculation showing the determination of this quantity is provided below. It should be noted that there is one other produc t which is a much larger parcel of propoxur, containing 55 gallons of product at 1 percent a.i. (Reg. No. 84 396-12). This product is also used for spot treatments by professional applicators us ing hand-held sprayers. However, the reference to spray cans shown below provides an clear pe rspective for the equivalent quantity of propoxur that would cause a concern for aquatic organism s associated with propoxur spot treatment use assuming that all of this quantity entered a water body.

Equivalent	number	of	spray	cans ൌ 11	g	propoxur ൬ 397	g	product

can ൰ ൈ 0.01fraction	of	propoxur

= 2.77 spray cans

The results above show the application of propoxur required to induce adverse impacts to propoxur for listed species on an acute basis based upon the adverse impact LOC of 0.05. Table
3.1 below summarizes these results for listed specie s and also includes the equivalent results for non-listed species based upon the acute adverse impact LOC of 0.5. . Due to a lack of scientifically-sound toxicological data, ch ronic exposure is not considered.

a Acute impacts based on the following calculation: Daphnid acute endpoint (EC 50 = 0.011 mg/L) x 0.05 or 0.5 (LOCs for listed and non-listed species). Daphnid acute endpoint from MRID No. 00149172.

b Based on the following calculation: Concentration of concern (mg/L) x Conversion factor (1,000 L/m 3 ) x Conversion factor (grams/1,000 mg) x Volume of standard pond (20,000 m 3 )

c Based on the following calculation: Propoxur mass of concern (grams) x Reciprocal of propoxur product density (gallon/0.065 lbs from Table 2.1 ) x conversion factor (lbs./453.6 grams)

d Based on the following calculation: Propoxur mass of concern (grams)/[Mass of product in spray can (grams) x % a.i.].

Refined Adverse Impacts Analysis

Table 3.1. Summary of propoxur application thresholds to trigger adverse impacts for listed and non-listed species on an acut e basis based on preliminary analysis.

Adverse Impacts

Thresholds Propoxur Water Body
Concentration

of Concern (mg/L) Propoxur
Mass of
Concern (grams) b Equivalent

Product
Amount (gallons) c Equivalent
Number of Spray Cans (quantity) d Acute Listed Species (LOC = 0.05) 5.5 x 10 -4 a 11 0.373 2.77

Acute Non-Listed Species (LOC = 0.5) 5.5 x 10 -3 a 110 3.73 27.70Page 23 of 39 The potential for the entire contents of 2.77 spra y cans or 11 grams of propoxur entering a water body from a property spot treated with propoxur can be further qualified by evaluating the amount of propoxur that can enter a water body via runoff at toxico logically relevant concentrations. Since runoff of propoxur is be ing evaluated, PRZM/EXAMS can be used to evaluate the amount of propoxur app lied that would be required to runoff in sufficient quantities to trigger adverse impacts to listed and non-listed a quatic species. Like the preliminary analysis above, this threshold will be based on the most sensitive endpoint for aquatic species ( daphnid .EC 50 = 0.011 mg/L) and LOCs for listed and non-listed species (LOC = 0.05 and LOC = 0.5, respectively). Therefore, the COCs determ ined from the preliminary analysis and shown
in Table 3.1 are still used in this analysis to define the concern for adverse impacts associated with propoxur spot treatments. However, in this analysis, the equi valent amount of propoxur applied that can cause adverse impacts can be de termined from the equiva lent application rate input into PRZM/EXAMS from a propoxur spot treatment application scenario which produce EECs equivalent to the COCs. However, due to information lacking on the label regarding propoxur spot treatment applications, the following assumptions were developed to define the application scenario for propoxur spot treatments:

The first assumption defining this application scenario will stipulate that only one propoxur application is made per year per site over time . The standard thirty-year simulation will be conducted in PRZM/EXAMS. Such an assumption w ith infrequent applications (one per year) is plausible for propoxur considering its very small overall usage.

The second assumption defining this application scenario will apportion aquatic exposure according to treatment source area characteristic s composing of 50 percent impervious surfaces and 50 percent residential ground surfaces. This apportionment to the source area is representative of many insect icide spot treatments for founda tions encompassing the foundation itself and the surrounding grounds. This is further described in insecticid e treatment surveys for pyrethroids provided by the Pyrethro id Working Group (MRID No. 49292101).

The third assumption is that the use of modeling scen arios in the evaluation represent environmental conditions which result in upp er-bound modeling concentrations. The CA Impervious Modeling Scenario was used to re present the impervious surface apportionment and the CA Residential Modeling Scenario was used to represent the residential grounds surface apportionment. It was verified th at this was a vulnerable scenario since the weather station used for San Francisco Airport (WBAN No. 23234) was found to result in mode ling concentrations similar to that resulting from climatologically wetter parts of the country such as Florida. 7

The fourth assumption is regarding the determination of the amount of propoxur resulting in the adverse impacts. It will be assumed that the amount of mass of propoxur will be evenly distributed to a 10-hectare watershed. However, given its limited use and therefore propensity for it not to be used in community treatments, th e calculation of the fina l determination of the amount of propoxur leading to adverse impacts will only assume that one property is treated per 10-hectare watershed. Other ecological risk asse ssments have assumed treatments to multiple properties over a 10-hectare watershed.

7 The verification involved PRZM/EXAMS modeling using the CA Impervious and CA Residential scenarios

simulated with 30-years of weathe r data from Tallahassee, FL.Page 24 of 39 The remaining parameterization for PRZM/EXAMS is composed of the physical chemical and fate properties of propoxur utiliz ing EFED Model Input Paramete r Guidance. The Surface Water Concentration Calculator interface (SWC C version 1.092, dated March 6, 2014) for
PRZM/EXAMS is used in this supplemental evaluation.

The application rate resulting in the acute COCs with the runoff scenarios may be determined by scaling the first-guess applicati on rate of 1 kg a.i./ha used in the PRZM/EXAMS simulation to the application rate where PRZM/EXAMS EECs are equivalent to the acute COCs. The computation below shows that an application rate of 0.008 kg/ha of propoxur would correspond
to an amount available for runoff to a water body which would result in adverse impacts for listed species on an acute basis:

Equivalent App. Rate Causing A dverse Impacts = Acute COC (0.55  g a.i./L) ÷

PRZM/EXAMS Peak EEC Normalized to First-Guess Application Rate (69.25  g a.i./L per kg a.i./ha) = 0.008 kg a.i./ha

Information on the PRZM/EXAMS simulations (e.g., input and processing to arrive at the results) is shown in Appendix A . Following the results calculated by PRZM/EXAMS, an equivalent minimum mass of 0.08 kg (80 grams) propoxur would have to be applied in order for enough of it to be available in runoff to cause adve rse impacts to listed species. This is shown by assuming that this mass is applied uniformally throughout a 10-ha watershed, and that only one
site is treated within this waters hed. The calculation is shown below:

Equivalent Mass Amount of Pr opoxur Causing Adverse Impacts = Equivalent App. Rate for Adverse Impacts (0.008 kg a.i./ha per site treated) x 10 ha = 0.08 kg a.i. = 80 grams of propoxur per site treated

A minimum of 80 grams of propoxur applied for adve rse acute impacts for listed aquatic species is equivalent to 20.15 spray cans or 2.75 gallons or of product. These calculations are shown
below:

Equivalent	number	of	spray	cans ൌ 80	g	propoxur ൬ 397	g	product

can ൰ ൈ 0.01fraction	of	propoxur

= 20.15 spray cans

Equivalent Product Amount Causing Adverse Impacts = Mass of propoxur causing adverse impacts = (80 grams) x Reciprocal of Pr opoxur Product Density (gallon/0.065 lbs from Table
2.1 ) x Conversion Factor (lbs./453.6 grams) = 2.75 gallons of product

The results above show the application of propoxur required to induce adverse impacts to propoxur for listed species on an acute basis based upon the adverse impact LOC of 0.05. Table
3.2 below summarizes these results for acute listed species and also includes the equivalentPage 25 of 39 results for non-listed species based upon the adve rse impact LOC of 0.5. . Due to a lack of scientifically-sound toxicological data, ch ronic exposure is not considered.

a Acute impact based on the following calculation: Daphnid acute endpoint (EC 50 = 0.011 mg/L) x 0.05 or 0.5 (LOCs for listed and non-listed species). Daphnid acute endpoint from MRID No. 00149172.

b Acute impact based on the following calculation: [COC (0.55  g a.i./L) ÷ PRZM/EXAMS peak EEC normalized to first-guess application rate (69.25  g a.i./L per kg a.i./ha)] x 10 ha watershed x Conversion Factor (1,000 grams/kg). Please refer to Appendix A for information regarding PRZM/EXAMS modeling.

c Based on the following calculation: Propoxur mass of concern (grams) x Reciprocal of propoxur product density (gallon/0.065 lbs from Table 2.1 ) x conversion factor (lbs./453.6 grams)

d Based on the following calculation: Propoxur mass of concern (grams)/[Mass of product in spray can (grams) x % a.i.].

As expected, the result in this refined analysis demonstrate that more propoxur has to be applied to exist at toxicologically relevant concentrations when its availability to runoff is considered versus when its availability to runoff is not considered as in the preliminary analysis.

Water Quality Monitoring Data

An extensive database of surface water and ground water monitoring exists for propoxur. However, there are no recent monitoring data available for propoxur beyond the year 2000 8

. Therefore, the existing monitori ng data would not reflect the a ny representation of the current usage of propoxur considering that overall scope of uses has drama tically decreased.

Incident Database Review

A review on April 28, 2014, of the Ecological In cident Information System (EIIS version 2.1, USEPA, 2008), which is maintained by the Agency’s Office of Pesticide Programs and the

8 Citation: National Water Quality Monitoring Council Water Quality Portal: http://www.waterqualitydata.us/

Table 3.2. Summary of propoxur application thresholds to trigger adverse impacts for listed and non-listed species on an acut e basis based on the refined analysis.

Adverse Impacts

Thresholds Propoxur Water Body
Concentration

of Concern (mg/L) Propoxur
Mass of
Concern (grams per site treated) Equivalent

Product
Amount (gallons) c Equivalent
Number of Spray Cans (quantity) d Acute Listed Species (LOC = 0.05) 5.5 x 10 -4 a 80 b 2.75 20.15

Acute Non-Listed Species (LOC = 0.5) 5.5 x 10 -3 a 800 b 27.50 201.50Page 26 of 39 Avian Monitoring Information System (AIMS), which is maintained by the American Bird Conservancy, indicates a to tal of three reported eco logical incidents associ ated with the use of

propoxur.

All of the propoxur incidents were classified as highly probable and a resu lt of misuse occurring between 1992 and 2000. All of the propoxur incidents involved birds and involved additional chemicals used in conj unction with propoxur.

 Incident 004169-075 was reported by the Virg inia Department of Game and Inland Fisheries in November 1992. After a group of thirty geese landed on a small pond, three dead geese were found floating in the water. Two of the dead geese were submitted for necropsy for pesticide analysis; residues of propoxur and famphur were found. It is suspected that the chemicals were misu sed to intentionally poison the geese.

 Incident 004169-079 was reported by the Virg inia Department of Game and Inland Fisheries in January 1993. A nu mber sick or dead starlings (18) fell from a tree at a residence in Wythe county in late January. Analysis of the stomach contents of birds were analyzed and found to contain high c oncentrations of famphur and propoxur. In addition to the incident, there were repor ts of a neighbor purposefully poisoning the starlings.

 Incident I011301-002 was reported by the Ne w York Department of Environmental Conservation in November 2000. A pigeon wa s found dead on a rooftop in Queens, New York adjacent to a pile of mush food made up of peanuts a nd green pellets; analysis of
the food showed the feed contained 424.2 mg/L of propoxur and 0.50 mg/L of
brodifacoum.

In addition to incidents recorded in EIIS, additio nal incidents have been reported to the Agency in aggregated incident reports. Pesticide registrants report cer tain types of incidents to the Agency as aggregate counts of incidents occurri ng per product per quarter. Ecological incidents reported in aggregate reports in clude those categorized as “mi nor fish and wildlife” (W-B), “minor plant” (P-B), and “other nontarget” (ONT) incidents. “O ther nontarget” incident include reports of adverse effects to insects and other te rrestrial invertebrates. For propoxur, registrants have reported 13 minor plant incidents, no mi nor fish and wildlife incidents, and no other nontarget incidents. The 13 plant incident s occurred between 1995 and 1998. One additional report of a wildlife incide nt was reported in 2011. No other de tails of the incidents are avialble.

Although incident reports for propox ur have not been received by the Agency since 2011 and only three major incidents have been reported to the Agency, the absence of reported incidents should
not be construed as the absence of incidents. Incident reports for non-target organisms typically provide information only on mortality events and plant damage incidents. Except for phytotoxic effects in terrestrial plants, subl ethal effects, such as reduced growth or impaired reproduction, are rarely reported. However, the inci dent data that are av ailable suggest that exposure pathways for propoxur are complete and that exposure levels are su fficient to result in field- observable effects.



### 3.2 Risk DescriptionPage 27 of 39 3.2.1 Exposure and Risk to Aquatic Organisms

The discussion for this risk description will be based on the refined analysis in Section 3.1 since these results encompass a feasible exposure potentia l of propoxur spot treatments to aquatic water bodies since this analysis accounts for propxur’s ava ilability in runoff. The underlying conclusions that can be developed from this analysis based upon the known use of propoxur outdoor spot
treatments are described below:

1. Propoxur risks to listed aquatic invertebrates associated with spot treatments are only possible to listed species on an acute basis. This finding is based on the effects observed to aquatic invertebrates most sensitive species ( daphid ), which may occur when greater than or equal to 2.75 gallons of product are applied (see Table 3.2 ). High-end propoxur spot treatment applications may potentially approach 2.75 gallons of product when hand held sprayers are used, mainly by professional applicators, most likel y occurring only when relatively large treatments to founda tions occur. However, it is important to note that while this potential exposure exists, th e potential is low. Furtherm ore, the equivalent threshold application of 20.15 spray cans of propoxur products that need to be used in order for propoxur to exist in high enough quantities to pose a concern is very large (see Table 3.2 ). Therefore, this suggests that spot treatments with propoxur using spray cans would not pose a concern as risks would occur due to exorbitant and implausible uses of propoxur.

2. Propoxur acute risks to non-listed aquatic species to aquatic speci es are not likely since the
results of the refi ned analysis in Section 3.1 indicate that propoxur w ould need to be used in quantities in the range of 27.5 – 114.1 gallons of produc t or 201.5 – 849.2 spray cans (see Table 3.2 ). These are very large amounts of propoxur for any type of spot treatments. Therefore, none of the propoxur spot treatment uses are anticipated to re sult in any concern to non-listed aquatic species on an acute basis.

As mentioned in the first point above, the poten tial for exposure leading to adverse impacts to listed aquatic species associated with hand-held spra y applications to foundations are small. This is qualified further below:

1. It appears that small applicati ons and non-frequent applications are typical consistent with usage data associated with propoxur s pot treatments. Please refer to Section 2.2 for details on the nationwide usage of propoxur . There is the propensity for small applications and non-frequent applications to be the prevailing trend for propoxur uses as suggested by small use volume for spot treatments. Therefore, propoxur product usage at 2.75 gallons would represent a very high applica tion than what would be expe cted given the usage data
available.

2. The limited use of propoxur also suggests that it is not used widely in an organized fashion within communities. Therefore, the amount of material used in outdoor spot treatments will not be used in copious amounts and dist ributed widespread among different regions.Page 28 of 39 3. Third, low use over specific areas are likel y for propoxur since labels do not allow broadcast or continuous banded type of applications outdoors in many cases.

It should be noted that further reductions in exposure would result if spot treatments occur at distances that are far en ough away from streams and water bodi es for propoxur to allow it become highly dispersed in runoff water upon entry to any downstream aquatic habitat. However, given propoxur’s high mobility and persistence in soil a nd water, especially in acidic and neutral environments, and high toxicity especially for aquatic invertebrates, even small exposures to propoxur occurring from spot treat ments close to streams and wa ter bodies may result and cause adverse impacts in aquatic habitats. Therefore, any possibility for exposure identified in this
assessment is limited to inst ances where spot treatments occur close to aquatic habitats.
Some of the current labels do not include hazar d statements related to aquatic organisms. Therefore, EFED recommends that protective measures for addressing aquatic organisms associated with outdoor propoxur spot treat ments be considered on future labels.

There are no reported incidents of propoxur exposur e to aquatic organisms resulting from spot treatment uses. However, the lack of incidences do not pre-empt any potential for risk identified for aquatic organisms.

3.2.2 Risks to Terrestrial Organisms

Exposure in terrestrial habitats would be contained within the ba it stations, and propoxur residues would not be bioavailable to terrestrial organisms to other uses included spot treatments, tape strips and insecticide tags. As there is no complete ex posure pathway to result in substantive exposure of non-target terrestrial organisms under the currently registered uses, EFED has presumed risk is
discountable to terrestrial organisms. Refer to Section 2.6 for the full discussion on this rationale.



### 3.3 Uncertainties, Limitations, and Data Gaps

There are many uncertainties related to propoxur, mainly related to th e instruction for its use on as a spot treatment on labels. However, there is some information submitted to the Agency that is valuable for use in the risk assessment and to use for the basis of default assumption for missing
parameters.

For example, for environmental fate data, there is some information lacking on facets of propoxur’s degradation in water. The hydrolysis study for propoxur indicates that it degrades mainly in alkaline environments (MRID No. 085762). However, the formati on of degradates were not quantitatively determined in the study submitte d to the Agency. In addition, there are no aquatic metabolism studies available for propoxur to confirm the alkaline-mediated mode of degradation found in the hydrolysis study. However, slow rates of degrada tion in weakly acidic conditions, consistent with the hydrolysis study, we re also found in flooded conditions within the existing anaerobic soil metabolism study (MRID No. 085768). Therefore, following these lines of evidence, the supplemental non-deterministic aquatic exposure calculations for propoxur assumed that propoxur’s half-lives in the aqua tic environment were parameterized as highly persistent following EFED’s modeling input parame ter guidance. Propoxur’s persistent propertiesPage 29 of 39 as the only stressor of concern is expected to be a conservative depiction of the exposure and risk profile from propoxur’s outdoor spot treatments c onsidering propoxur’s high toxicity especially for aquatic invertebrates.

Additionally, data gaps exist in the ecotoxicological profile for propoxur. For aquatic organisms, which are only expected to be potentially adversely impacted from outdoor propoxur spot treatment applications close to water bodies, there are on ly three acceptable st udies available (two
acute studies for freshwater fish and one acute study for freshwater invertebrates). One chronic study for aquatic invertebrates (MRID 41425301) is av ailable but is classifi ed as supplemental; classification was due to a lack of reporting on a nu mber of factors including health and history of organisms at start of testing, volume of test solution and loading fact or, total organic carbon, length, bodyweight, and number of o ffspring per female. These deviat ions resulted in invalidation of the endpoints for quantit ative use. Therefore, no scientifically sound data are available to assess the potential application threshol d of propoxur leading to adverse impacts to aquatic species on a chronic basis. However, the underlying conclusi on that adverse impacts resulting from propoxur use are only possible where applications occur cl ose to streams and water bodies would not be different due to chronic exposure considerations; adverse impacts would not anticipated to occur with spot treatments which occu r over large distance from aquatic habitats. Furthermore, any protective measures placed on the label addressi ng potential exposure to aquatic invertebrates restricting outdoor spot treatment s to areas far away from streams and water bodies would reduce any concerns for exposure.

Besides data gaps, there is a substantial lack of informati on related to propoxur outdoor spot treatments on labels. First, there are not maximu m application rates specified. In addition, there
is no information or restriction on propoxur retreatments included on any label’s instructions. As
a result of this lack of information and lack of a standard approach existent to evaluate outdoor spot treatments for risk assessments, a qualitative evaluation which back- calculated the amount of propoxur which would be required to be applied to induce advers e impacts based upon available toxicological data was conducted. Considering that propoxur spot tr eatments are expected to cover small discontinuous areas based on its limited use, any potential exposure causing adverse impacts for listed aquatic species resulting from hand-held spot treatment applications of propoxur is only defined to exist for treatments occurring close to streams or water bodies. Assumptions regarding the application scenario for the refined assessm ent conducted to evaluate the potential exposure causing adverse impacts is described in Section 3.1 . The assumptions considered the scope of outdoor spot treatment uses of propoxur coupled with existing information on its overall low use
volume nationwide. It should be noted that the assumption related to the 50 percent apportionment of the treated area to impervious surfaces an d the remaining 50 percent to residential nonimpervious surfaces was based on the survey data for pyrethroid residential uses (MRID No. . 49292101). While there may be uncertainty of the nature of the related surfaces for propoxur, it is expected that the proportion of propoxur imp acted by impervious and non-impervious surfaces to be similar to pyrethroids even given propoxur’s small applications as co mpared to pyrethroid. The apportionment mentioned above used to eval uate the potential aquatic exposure related to propoxur spot treatments is consis tent with previous aquatic exposure assessm ents for pyrethroids conducted to support ecological risk assessments. For details on the assumptions, please refer to
Section 3.1 or Appendix A for information on the PRZM/EXAMS input parameters that were used to address spot treatments which may occur around foundations.Page 30 of 39 

## 4. Federally Threatened and Endangered (Listed) Species
Concerns

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2), requires all federal agencies to consult with the National Marine Fisheries Service (NMFS) for marine and anadromous listed species, and/or the United Stat es Fish and Wildlife Serv ice (USFWS) for listed wildlife and freshwater organisms, if they are proposing an "action" that may affect listed species or their designated critical habita t. The federal action addressed he rein is the proposed registration renewal of propoxur outdoor uses and it is expected that the use could o ccur nationwide. For a more detailed general descriptio n of the Endangered Species asse ssment process and the various components and assumptions of this process see Appendix B at the end of this document.

For the outdoor uses of propoxur, risk only to listed species from acute exposure is possible for aquatic invertebrates associated with hand-held sprayer spot treatment uses for propoxur occurring close to streams or water bodies. However, the Agency has determined
that there will be no habitat modi fication of any designated critical habitat for listed species from the current registered uses of propoxur . No other acute risks of concern were identified for non-listed aquatic invertebrates other listed or non-listed aquati c organisms including freshwater fish, estuarine/marine fish, and estuarine/marine invertebrates.

Conclusions regarding terrestrial organisms and plants are based on the lack of a complete exposure pathway ( Section 2.6 ). Exposure in terrestrial habitats would be limited, and therefore, listed species are not expected to be impacted from outdoor propoxur uses.

Risk determinations by taxa for listed species are summarized in Table 4.1 below. A,“No Effect” risk determination for all listed species can be c oncluded for direct and indirect effects of propoxur use except for aquatic invertebrate s either as there is no comple te exposure pathway or adverse impacts are not expected. A “May Affect” determinati on is stipulated at this time for direct effects to aquatic inverteb rates resulting from propoxur spot treatm ent use close to streams since adverse impacts are possible. This determination may be clarified further in the future depending on clarification of uncertainties which currently exist on product labels regarding propoxur spot

treatments.

Table 4.1. Potential Risks to Listed Taxa Asso ciated with Direct or Indirect Effects from the Currently Registered Uses of Propoxur.

Listed Taxon Direct Effects Indirect Effects

Terrestrial and semi-aquatic plants – monocots No Effect

Terrestrial and semi-aquatic plants – dicots No Effect

Birds No EffectPage 31 of 39 Table 4.1. Potential Risks to Listed Taxa Asso ciated with Direct or Indirect Effects from the Currently Registered Uses of Propoxur.

Listed Taxon Direct Effects Indirect Effects

Terrestrial-phase amphibians and reptiles No Effect

Mammals No Effect

Terrestrial invertebrates No Effect
Aquatic nonvascular plants No Effect

Aquatic vascular plants No Effect

Freshwater fish No Effect
Aquatic-phase amphibians No Effect

Freshwater invertebrates May Affect* No Effect

Marine/estuarine fish No Effect

Marine/estuarine invertebrates No Effect
*Determination based on direct effects to listed species on an acute basis, only possible resulting from propoxur outdoor spot treatments using hand held sprayers applied to foundations which occur close to streams and water
bodies. This determination may be clarified further in the fu ture depending on clarification of uncertainties which currently exist on product labels regarding propoxur spot treatments.



## 5. Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews num erous studies to asse ss potential adverse outcomes from exposure to chemicals. Collectiv ely, these studies includ e acute, subchronic and chronic toxicity, including asse ssments of carcinogenicity, ne urotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include e ndpoints which may be susceptible to endocrine influe nce, including effects on endocri ne target organ histopathology, organ weights, estrus cyclicity, sexual maturatio n, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess gr owth, developmental and reprod uctive effects in different taxonomic groups.

EPA has developed the EDSP to determine whet her certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or ot her such endocrine effect s as the Administrator may designate.” The EDSP employs a two-tiered approach to making th e statutorily required
determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrog en, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of th e Tier 2 tests are necessary base d on the available data. Tier 2 testing is designed to identify a ny adverse endocrine-related eff ects caused by the substance, and establish a dose-response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, which contains 58 pest icide active ingredient s and 9 inert ingredients. A second listPage 32 of 39 of chemicals identified for EDSP sc reening was published on June 14, 2013 9 and includes some pesticides scheduled for registration review and chemicals found in water

. Neither of these lists
should be construed as a list of know n or likely endocri ne disruptors.

Propoxur is not among the group of 58 pesticide activ e ingredients receiving EDSP test orders.
For information on the status of the orders i ssued under the EDSP for each chemical, please visit our website at http://www.epa.gov/endo/ and click on the "Status of EDSP Orders/DCIs" in the Highlights Box. Additional info rmation on the EDSP, including th e policies and procedures, the list of 67 chemicals, the test guid elines and the Tier 1 screening battery, can al so be found at this
website.

9 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of

chemicals.Page 33 of 39 

## 6. References

American Conference of Governme ntal Industrial Hygienists, In c. 1986. Documentation of the threshold limit values and biological exposu re indices. Fifth edition. Cincinnati, OH: Publications Office, ACGIH.

American Housing Survey for the United Stat es, 2011. Department of Housing and Urban Development and U.S. Census Bureau.

Berg, G. L., ed. 1986. Farm Chemicals Handb ook. Willoughby, Ohio: Meister Publishing Co. Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeg er. 1994. Literature review and evaluation of the EPA food-chain (Kenaga) nomogram, an instrument for estimating pesticide residues on plants. Envi ron. Tox. Chem. 13:1383-1391.

California DPR Pesticide Us e Reporting. 2012. Chemical data. Available at: http://www.cdpr.ca.gov/doc s/pur/pur12rep/chmrpt12.pdf

Hayes, W. J. 1982. Pesticides studied in man. Baltimore, MD: Williams and Wilkins

Hoerger, F. and E. E. Kenaga, 1972. Pesticide Re sidues on Plants: Correlation of Representative Data as a Basis for Estimation of their Magnitu de in the Environment. In F. Coulston and F. Korte, eds., Environmental Quality and Safety: Ch emistry, Toxicology, and Technology, Georg Thieme Publ., Stuttgart, West Germany, pp. 9-28.

TOXNET. 1986. National library of medicine's toxi cology data network. Hazardous Substances
Databank. Public Health Service. National Institute of Health. U.S. Department of Health and Human Services. Bethesda, MD: NLM.

USEPA. 1975. Ney, Ronald E Jr . Registration – Baygon MOS Inse cticide. File No. 2075270 U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. August 13, 1975.

USEPA. 1976. Ney, Ronald E Jr. For use on mole cricket bait on lawn, gol f courses, ornamental turfs, and pastures. U.S. E nvironmental Protection Agency, Office of Pesticide Programs,
Environmental Fate and E ffects Division. August 4, 1976.

USEPA. 1977a. Cook, N. Registration for Use around the house. File No. 5719-AA. U.S. Environmental Protection Agenc y, Office of Pesticide Progra ms, Environmental Fate and Effects Division. January 18, 1977.

USEPA. 1977b. Windberg, L.A. Amendmen t to Registration. File No. 3125-214, 3125-122, 3125-146. U.S. Environmental Protection Ag ency, Office of Pesticide Programs,
Environmental Fate and Eff ects Division. November 23, 1977.

USEPA. 1977c. Windberg, L.A. and R.W. Holst. Amendment to Registration to Alfalfa and Pasture grass and Registra tion. File No. 3125-146 and 3125-GNA. U.S. EnvironmentalPage 34 of 39 Protection Agency, Office of Pesticide Pr ograms, Environmental Fate and Effects Division. November 22, 1977.

USEPA. 1977d. Sanders, F. Registration of SM CP Baygon 2% Mole Cricke t Bait Insecticide.
File No. 6720-EAU. U.S. Environmental Prot ection Agency, Office of Pesticide Programs,
Environmental Fate and Eff ects Division. January 13, 1977.

USEPA. 1977e. Windber g, Lamar A. Amendment to Registration – Barns. File No. 2075281. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. November 23, 1977.

USEPA. 1977f. O’Brien, Thomas F. Registra tion-Best Earwig and Sowbog Bait. File No. 2075278. U.S. Environmental Protection Ag ency, Office of Pesticide Programs,
Environmental Fate and E ffects Division. August 5, 1977.

USEPA. 1977g. Ney, Ronald E Jr. Registration for control of ants, including fire ants + carpenter
ants. File No. 2075277. U.S. Environmenta l Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. February 17, 1977.

USEPA. 1977h. Ney, Ronald E Jr. For use on al falfa and pasture grass to control mosquitoes.
File No. 2075279. U.S. Environmental Protec tion Agency, Office of Pesticide Programs,
Environmental Fate and Eff ects Division. September 21, 1977.

USEPA. 1977i. Cook, Norman J. Registration for Use around the house. File No. 2075274. U.S. Environmental Protection Agenc y, Office of Pesticide Progra ms, Environmental Fate and Effects Division. January 18, 1977.

USEPA. 1978a. Craven, Henry T. Regi stration – Ant Trap. Acc No. 094546. U.S. Environmental Protection Agenc y, Office of Pesticide Progra ms, Environmental Fate and Effects Division. October 6, 1978.

USEPA. 1978b. Tice, John. Registration of Ne w Product – Grant’s Ant Control-Jel. Acc No. 232459. U.S. Environmental Protection Ag ency, Office of Pesticide Programs,
Environmental Fate and Eff ects Division. October 27, 1978.

USEPA. 1983. Balcomb, R. Proposed Secti on 18 for use over flowing water to control mosquitoes. File No. 83-CA-76. U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. July 8, 1983.

USEPA. 1987. Noles, John. Propoxur Registration Standar d. Record No. 2075291 U.S. Environmental Protection Agenc y, Office of Pesticide Progra ms, Environmental Fate and Effects Division. May 5, 1987.

USEPA. 1990. Felthousen, R.W. Amendment- Label Revision-Data Re quired. DP Barcode 154393. U.S. Environmental Protection Ag ency, Office of Pesticide Programs,
Environmental Fate and E ffects Division. August 15, 1990.Page 35 of 39 USEPA. 1991. Rexrode, Miachel. Label Revi ew for Registration. File No. 62451-R. U.S. Environmental Protection Agenc y, Office of Pesticide Progra ms, Environmental Fate and Effects Division. January 24, 1991.

USEPA.1996a.Food Quality Protection Act. http://www.epa.gov/oppsrrd1/registration_review/

USEPA. 1996b. Reregistration Eligibility Do cument for Propoxur, Science Chapter. U.S. Environmental Protection Agency, Office of Pesticide Programs. July 10, 1996.

USEPA. 1998. Guidelines for Ec ological Risk Assessment. Risk Assessment Forum, Office of Research and Development, Washington, D.C. EPA/630/R-95/002F. April 1998. http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

USEPA. 2004. Overview of the Ecological Risk Assessment Proce ss in the Office of Pesticide Programs. U.S. Environmental Protection Ag ency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004.

USEPA. 2006. N-methyl Carbamate Revised Cumu lative Risk Assessment. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. September 24, 2007.

USEPA. 2008a. ECOTOXicology Database. Office of Resear ch and Development National
Health and Environmental Effects Research Laboratory’s (NHEER L’s) Mid-Continent Ecology Division (MED). June 30, 2008. http://cfpub.epa.gov/ecotox/

USEPA. 2008b. Ecological Incident In formation System. June 24, 2008. http://www.epa.gov/espp/consultation/ecorisk-overview.pdf

U.S. Environmental Protection Agency. 1986 (Jan). Estimating pesticide sorp tion coefficients for
soils and sediments. Richard E. Green and Sa muel W. Karickhoff. E nvironmental Research Laboratory. Office of Research a nd Development. Athens, GA.

U.S. Environmental Protection Agency. 1984 (Dec.). User's manual for the pesticide root zone model (PRZM). Release 1. Athens, GA: Environmental Research Laboratory.

U.S. Fish and Wildlife Service (USFWS) and Na tional Marine Fisheries Service (NMFS). 1998. Endangered Species Consultation Handbook: Pr ocedures for Conducti ng Consultation and Conference Activities Under Section 7 of the Endangered Species Act. Final Draft. March

1998.

Worthing, C. R., ed. 1983. The pesticide manua l: A world compendium . Croydon, England: The British Crop Protection Council.Page 36 of 39 

## Appendix A Qualitative Aquatic Exposure Modeling Summary

Table A.1. Summary of PRZM/EXAMS input pa rameter values for physical chemical and fate properties used for propoxur surface water aquatic EECs associated with outdoor spot

treatments.

PRZM/EXAMS Input Parameter Input Value and Unit Source Physical Chemical Property Parameters Molecular Weight 209.2 g/mol MRID No. 151791 Solubility in Water 1,974 mg/L EpiSuite, WSKOW v.1.42 Vapor Pressure 6.5 x 10 -6 torr@ 25°C Worthing C.R., 1983 Environmental Fate Property Parameters Soil-Water Partition Coefficient (K d ) 0.23 mL/g MRID No. 085770

Average of K d values from sandy loam, silt loam, and silty clay soils Hydrolysis (t 1/2 ) Stable MRID No. 085762

Value for pH7 Aqueous Photolysis (t 1/2 ) 13 days MRID No. 085763

Aerobic soil metabolism (t 1/2 ) 267.59 days MRID No. 085768

90 th percentile upper
confidence bound from silt loam and sandy loam soil Aerobic aquatic metabolism (t 1/2 ) 535.18 days EFED Model Input
Parameter Guidance for Data Gap

t 1/2 = Aerobic soil metabolism
half-life x 2 Anaerobic aquatic metabolism (t 1/2 ) Stable MRID No. 085768

No metabolism evident in water layer as degradation was equivalent in sterile versus non-sterile samples.Page 37 of 39 Table A.1. Summary of PRZM/EXAMS input pa rameter values for physical chemical and fate properties used for propoxur surface water aquatic EECs associated with outdoor spot

treatments.

PRZM/EXAMS Input Parameter Input Value and Unit Source Application Parameters Modeling Scenarios, Meteorological Station, Application Rate, Number of Applications, and Application Date CA_RLF Impervious & CA_RLF Residential

 Weather Station: W23234 (San Francsico)

 Application Rate: 1.0 kg a.i./ha

 1 application per year

 Application Date:

Nov. 10  Application dates conservatively selected
based on maximum rainfall climatological date at meteorological
station defined in each modeling scenario site after crop emergence date specified in PRZM crop scenario.

 Application rates
calculated based on assumptions for
propoxur spot treatments defined in
Section 6.1 Chemical Application Method Ground Application Propoxur product labels for spot treatment applications

Application Efficiency 0.99 EFED Model Input
Parameter Guidance

Spray Drift Fraction 0 Assumption for spot treatment applications* * Spray drift not anticipated exposure route for spot treatment applications.

Table A.2. Determination of total exposures determined from aquatic EECs from modeling scenarios for propoxur spot treatments.

Scenario Percent
Contribution (%) Peak EEC (ppb per kg/ha) 21-day EEC (ppb per kg/ha) 60-day EEC (ppb per kg/ha) Surface Type Scenario Source Apportionment EECs CA Impervious 50 133 131 125.75

CA Residential 50 6.38 6.25 6.13 Composite One-in-Ten Year EEC from Above Surface Source Apport ionment Contributions Total Exposure * 69.25 68.25 66.63

* Total exposure determined by weighted average of contributions from apportionments of source surface type

defined in modeling scenario. Post-processing with daily concentrations from PRZM/EXAMS 30-year simulation
with each scenario was conducted to determine the one-in-ten year composite aquatic EEC.Page 38 of 39 

## Appendix B Endangered Species Assessment Information

At this current stage of the Registration Review process, it is premature to make effects determinations for listed species until furthe r refinements are conducted. To make effects determinations for individual sp ecies, useful refinements may include analyses of 1) more detailed, species-specific eco logical and biological data; 2) more detailed and accurate information on Propoxur use patterns; and 3) sub-c ounty level spatial proximity data for the cooccurrence of potential e ffects areas and listed species and a ny designated critical habitat. Examples of such refinements are described below.

EFED is currently developing tools that are expe cted to further refine the assessment and are designed to support effects determinations for individual federally list ed species and their designated critical habitats (whe re applicable). Scientific in formation obtained from the U.S. Fish & Wildlife Service (USFWS), the National Marine Fisheries Service (NMFS), and other reliable sources is being colla ted by EFED to address all cu rrently listed species. The information will be stored in an Office of Pesticide Programs Pesticide Registration Information SysteM (PRISM) knowledgebase. The listed species knowledgebase will consist of an information repository that houses biological and behavioral info rmation relevant to individual species ( e.g. , habitat, diet, and life history, including specific temporal and spatial associations) and a document repository that contains supporting documents ( e.g ., USFWS recovery plans) and electronic information ( e.g ., GIS data files).

Refinements may also include more detailed analyses of the registered uses and their use patterns that result in LOC exceedances for federally list ed species in the screening-level assessment. The analyses may include more information on where, when, and how Propoxur is used. Actual usage data (when available) and national land-cov er datasets that indica te potential use sites [ e.g ., national land cover dataset (NLCD), crop data layer (CDL)] may be us ed to support a more refined analysis of where Propoxur is reasonably e xpected to be used. Similarly, refinements for the timing of applications and how Propoxur is us ed may be based on the analysis of additional usage data, beyond what were available at the time of the screening-level assessment, and a more in-depth exploration of agronomic practices.

The U.S. Environmental Protection Agency, along with the U.S. Department of Agriculture (USDA), the U.S. Fish and Wildlife Service (FWS ), and the National Mari ne Fisheries Service (NMFS), have announced the availability of a report developed by the National Academy of Sciences’ National Research Council outlining recommendations on specific scientific and
technical issues related to the development of endangered and threatened species risk assessments for pesticides that are compliant with the Endangered Species Act (ESA) and the Federal Insecticide, Fungicide, and Roden ticide Act (FIFRA). The EPA, USDA, FWS and NMFS asked the NRC to consider a range of scientific and technical issues including: • identifying best available scientific data and information; • considering sub-lethal, indire ct and cumulative effects; • assessing the effects of chemical mixtures and inert ingredients; • analyzing the effects of pesticid e use through the us e of models;Page 39 of 39 • incorporating uncertainties into the evaluations; and • using geospatial information and datasets th at can be employed by the agencies in the
course of these assessments.

After reviewing the NRC’s recommendations on th ese scientific and technical issues, the EPA and its federal partners will determine how th ese recommendations can be implemented and incorporated into the scientific approaches for developing listed species ri sk assessments. It is anticipated that any draft guida nce and/or science policies de veloped by EPA and its federal partners as a result of the NAS recommendations would be released for public comment prior to implementation.

The refinements based on individu al species data; additional, de tailed usage information, when available; and further recommendations from th e NRC report are expected to help to more accurately identify potential area s of effect and to better inform effects and habitat determinations for listed species and any designated critical habitats. For example, if quizalofopp-ethyl is used when a particular species of concern is not present ( e.g ., it is migratory) or is not co-located in space, then risk of potential direct effects to the sp ecies may often be precluded. If LOCs are still exceeded for monocots, mammals, freshwater invertebrates, estuarine/marine invertebrates, and freshwater fish after conducti ng the refined analyses, further analyses of the potential spatial and temporal co-occurrence of listed specie s of concern (and any designated critical habitat) may be conducted. The extent of possible refinement in the analyses ofspatial/temporal co-occurrence will largely depend on the scale and quality of the available subcounty level use site ( e.g ., NLCD, CDL) and species location data

.