UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C

., 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### September 15, 2015



### MEMORANDUM

Subject: Registration Review: Ecological Risk Assessment for Terbufos PC Code: 105001

DP Barcode : 407573

From: MichaelLowit

, Ph.D

. ,Ecologist

# ~~/~ 

# 9/t ) (<"°

_ Faruque Khan

, Ph

. D

. , Senior Fate Scientist

## ~L~-' c; 

# Ir 

# r/r 

# rSujatha Sankula

, Ph.D.

, Branch Chief

## ~**~ ~-**  

# er\**I~** 

## 1-SE nvironmental Risk Branch I

### ~v-....__ - Ck 

### :.;;.>?

_ 

### Environmental Fate and Effects Division (7 07P)

To: Matthew Manupella

, Chemical Review Manager

Tom Myers

, Team Leader

Kevin Costello

, Branch Chie f

Risk Management and Implementation Branch II

Pesticide t.. e-Eva lu ation Division (7508P)

The Environmenta l Fate and Effects Division (EFED) conducted an ecological risk assessment
for the Registration Review of terbufos

, a systemic organophosphate used as an insecticide and

nematicide to control a variety of pests on com
, sorghum

, and sugar beet. The assessment is

attached

.

### 1 

# REGISTRATION REVIEW

ECOLOGICAL RISK ASSE SSMENT AND

EFFECTS DETERMINATIO N



# Terbufos

CAS Number : 13071

- 79

- 9

PC Code : 1 05001

Prepared by:

Michael Lowit, Ph.D., Ecologist Faruque Khan , Ph.D., Senior Fate Scientist

Reviewed by:

Edward Odenkirchen, Ph.D., Senior Science Advisor Stephen Wente, Ph.D., Biologist Meghan Radtke, Ph.D., Biologist Sujatha Sankula, Ph.D., Branch Chief U. S. Environmental Protection Agency Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch I 1200 Pennsylvania Ave., NW

Mail Code 7507P Washington, DC 20460

### 2 I. Executive Summary

Terbufos is a systemic organophosphate insecticide

- nemat i cide used to control a variety of pests on corn (field and sweet corn) , grain sorghum, and sugar beet . Terbufos was first registered in 1974 and was most recently reviewed in 1999 (USEPA, 1999; reregistration eligibility decision document (RED)). P revious risk assessments concluded that ecological risks to aquatic an d terrestrial organisms were of concern to the Agency. Specifically, the fish kill incidents associated with the use of terbufos on corn was a major consideration in the risk mitigation plan

outlined in the 2001 Interim Reregistration Eligibility Decision ( IRED ; USEPA, 2001 ) for

terbufos . Mitigation efforts included a reduction in the application rate for sorghum, a label requirement for maintaining setbacks and vegetative buffers adjacent to terbufos treated areas, the removal of the “over the top” application for European corn borer control on corn, and a label change for banded applications on corn (use a 7 inch band over the row, in front of the press wheel, and incorporate into the top 1 inch of soil).

The relatively high vapor pressure ( 3.16E

- 0 4 mm Hg at 2 5 °C ) and Henry's Law Constant ( 2.46

E

- 0 5 atm m 3 

### /mol ) of terbufos suggest that some of the parent compound will dissipate by

volatilization from moist soil and water bodies into the atmosphere. Terbufos is also susceptible

to degradation and tra nsform ation by both abiotic and biotic processes. T erbufos is moderately mobile to slightly mobile in soil. Three major degradates were identified in the environmental fate studies: terbufos sulfoxide, terbufos sulfone , and formaldehyde . Terbufos sulfoxide and terbufos sulfone have low soil partition coefficient (K d 

### ) values ranging from 0.40 to 2.93 mL/g

and DT 50s 

### of 136 to 174 days in soil suggest ing that they are more mobile and persistent than

terbufos in the environment.

Terbufos is very highly toxic to fish

, aquatic invertebrat e s
, and mammals, highly toxic to birds

, and moderately toxic to bees on an acute basis. C h r o nic effects are observed in both aquatic

and terrestrial animals at low concentrations. Some effects are observed in plants; however,

to xicity to plants is relatively low compared to animals

. Available data indicate that two major degradates (terbufos sulfoxide and terbufos sulfone) are similar to terbufos in toxicity ; thus, they are considered degradates of concern . Field data show avian and m ammalian mortality

associated with terb uf os use . In addition, there a r e a large nu m ber of reported f ish kills

attributed to the use of te r bu f os.

This assessment considers the most up to date toxicology and fate data, uses c urrent exposure models including those exploring pathways not quantitatively assessed in past risk assessments ( e.g. , drinking water and inhalation exposure), and considers the most recent labels (including a newer formulation, 20G), incident information, and monitoring data. Based on the latest information, conclusions of this assessment are substantially similar to those of the RED. An acute and chronic risk concern is expected for direct effects to both listed and non

- listed species of birds, mammals, fish, aquatic invertebrates, and terrestrial invertebrates. The Agency does not currently have the capability to quantitatively assess the effectiveness of the required vegetative buffers; however, based on a review of research studies it was hypothesized that buffers may

reduce the loading of total toxic residues of terbufos in aquatic systems between 50% and 90%. Although loading may be reduced up to 90%, the overall risk concerns for fish and aquatic invertebrates remain because risk quotients (RQs) re main above the levels of concern (LOC) after accounting for those reductions

. Previous assessments did not consider risk to plants due to

### 3 a lack of data. This assessment concludes that there is not a risk concern for direct effects to aquatic and terrest rial plants. In conclusion, consistent with past assessments there is a risk concern for aquatic organisms and terrestrial wildlife including listed species for the labeled uses

of terbufos.

Table 1 . Summary of Direct and Indirect Effects Associated wit h Registered Uses of

Terbufos

Taxon Risk Concern for

Direct Effects? Risk Concern for

Indirect Effects to

Listed Species? Non

- Listed Listed Birds, reptiles, and terrestrial

- phase amphibians Yes Yes Yes

Mammals Yes Yes Yes

Terrestrial invertebrates (honeybees) 1 Yes Yes Yes Terrestrial (upland and semi

- aquatic) plants

– monocots No No Yes Terrestrial (upland and semi

- aquatic) plants

– dicots No No Yes Freshwater fish and aquatic

- phase amphibians Yes Yes Yes

Marine/estuarine fish Yes Yes Yes

Freshwater invertebrates Yes Yes Yes

Marine/estuarine invertebrates Yes Yes Yes Aquatic vascular plants No No Yes Aquatic non

- vascular plants No N/A N/A

1 Honeybee is used as a surrogate for terrestrial invertebrates. Honeybees were not assessed quantitatively due to a

lack of oral (dietary) toxicity data for adults or larvae ; however, risk is expected for terrestrial invertebrates given

that terbufos is an insecticide.

N / A = Not applicable . There are no aquatic non

- vascular plant species that are listed at this time.



### II. Use Characterization and Methods of Application

Terbufos is used on corn, sorghum, and sugar beet to control a variety of insects and nematodes

. Use data from 2004

- 2012 indicate an annual average domestic use of approximately 740,000 pounds of terbufos active ingredient (USEPA, 2014). Terbufos is applied in bands, in

- furrow, or

knifed

- in. All uses require ground application and soil incorporation to a specified depth depending on the use. The timing of application is at

- plant ing, at

- bedding, post emergence , or at
cultivation. Terbufos is applied only one time a year for all uses. The labels provide rates in terms of lb ai/A and lb ai/1000 ft row. On a per acre basis, t he maximum application rate for

corn is 1.3 lb ai/A except for a Special Local Need (SLN) registration (NC920001) in North

Carolina that allows use on corn up to 2.6 lb ai/A. The maximum application rate s for sorghum and sugar beet are 1.695 lb ai/A and 1.96 lb ai/A , respectively

. Use information was obtained from the chemical profile produced by the Biological and Economic Analysis Division (BEAD)

. EFED used application scenarios that result in maximum exposure from a given use for the risk

assessment.

In addit ion to the technical product, there are three registered end

- use granular formulations:

Counter ® 

### CR (EPA Reg. No 241

- 314), Counter ® 

### 15G (EPA Reg. No. 5481

- 545), and

Counter ® 

### 20G (EPA Reg. No. 5481

- 562).

As a result of the terbufos IRED ( USEPA, 2001 ), setback s and buffers were added to terbufos product labels. The following distances are to be maintained: ( 1) a 500 ft vegetative buffer

between the treated area and surface water o n neighboring land, ( 2) a 500 ft vegetative buffer

### 4 between a standpipe drain outlet and surface water on neighboring land, ( 3) a 66 ft setback between the treated area and entry points to surface water bodies on non

- highly erodible soi ls

and a 300 ft setback on hi ghly erodible soils, ( 4) a 66 ft setback between the treated area and standpipes on terraced fields as well as a 66 ft vegetative buffer between the tile outlet and surface water bodies, and ( 5) a restriction on loading, rinsing, and washing equip ment within 300

ft of surface wat er bodies or within 50 ft of wells unless conducted on an impervious surface. All setbacks must be planted with a crop or seeded with grass or other suitable cover. All vegetative buffers must be seeded with grass or other suitable cover.

III. Summa ry of Environmental Fate

3.1 Terbufos

Selected physical, chemical and environmental fate properties of terbufos are listed in Table 2

. The solubility of terbufos in water is 5.4 mg/L at 25 o C. The relatively high vapor pressure (3.16E

- 0 4 mm Hg at 2 5 °C) and Henry's Law Constant of 2.46 E

- 0 5 atm m 3 

### /mol suggest that

terbufos will dissipate by diffusion from moist soil and water into the atmosphere, but the amount that may volatilize will vary depending on the use site conditions and the application

meth od . Volatilization may be a major dissipation route for terbufos that remains on the soil surface after incorporation. However, vapor

- phase terbufos is susceptible to atmospheric degradation by reaction with photochemically

- produced hydroxyl radicals ; the half

- life in air is

estimated to be 0.53 hours (EPISUITE 4.1). T erbufos residue w ere not detected in rain or snow samples monitored in several states (IA , IN, NY, OH and WV) (Majewski and Capel, 1995).

Terbufos is susceptible to transformation by both abiotic and biotic processes. All DT 50 

### values were calculated using nonlinear regression and single first order ( SFO )

, double first order in parallel ( DFOP ) , or intermediate order rate equation ( IORE ) equations (USEPA, 2012a)

. Appendix A provides estimated DT 50s 

### for the submitted environmental fate studies. T he hydrolysis half

- life for terbufos is less than 2 days in the typical range of environmental pH values (5, 7, and 9). In another study, terbufos hydrolyzed with a half

- life of less than 2 weeks at pH 4, 7, and 9. However, in an aerobic aquatic metabolism study, terbufos degraded in the water

column with a half

- life of less than 2 days, which is consistent with the results from the recent hydrolysis study (MRID 44862502). The metabol ic half

- life of terbufos in aerobic soil ranges from 5.9 to 10.2 days and in anaerobic soil is 67.5 days

. Kd values ranging from 5.42 to 14.6 mL/g suggest that terbufos is moderately mobile to slight ly mobile in soil

, according to a

classification scheme of the Food and Agricultural Organization of the United Nations (USEPA,

2006 a ).

The terrestrial field data indicate that terbufos dissipated in the field with half

- lives of 6.01 days in loamy soil from Illinois, 56.8 days in sandy loam soil from Colorado

, and 22.2 days in sandy

loam from California. Except for the Colorado soil, these half

- lives are comparable to findings from the aerobic soil metabolism study discussed above (DT 50s 

### <11 days). Data from the open

lit erature (Felsot, et al., 198 2 ) reported field half

- lives of 11

- 16 days for terbufos in silt loam and silty clay loam soils when terbufos was applied at a rate of 1.0 lb ai /A.

### 5 The log K
ow 

### (n

- Octanol

– water partition coefficient) of 4.71 indicates potential bioaccumulation of terbufos in aquatic organisms. The maximum terbufos bioaccumulation factors in bluegill sunfish were 320, 940, and 680X in edible tissues, non

- edible tissue, and whole fis h, respectively. At the end of the 14

- day depuration period, the reduction in residues was 84% for

fillet tissue and 93% for visceral tissue and whole fish. The single first order elimination rate

was calculated as K T 

### = 0.31 d

- 1 

### (DT 50 

### = 2.24 days). Two m ajor metabolites were identified: terbufoxon (CL94221) and a methane related compound (CL202474).

Table 2 . Physical, Chemical and Environmental Fate Properties of Terbufos

Property Value Source (Classification)

Common name Terbufos MRID 41297901

CAS Registry No. 13071

- 79

- 9

---

PC Code 105001

---

Chemical name (CAS) S

- [[(1,1

- dimethylethyl)thio]methyl]O,O

diethylphosphorodithioate MRID 41297901

SMILES notation CCOP(=S)(OCC)SCSC(C)(C)C EPISUITE 4. 1 1

IUPAC name S

- tert

- butylthiomethyl O,O

- diethyl phosphorodithioate TOXNET

Synonyms CL 92100, AC 92100 MRID 41373604

and 4 4 862501

Structure TOXNET

Molecular formula C 9 H 21 O 4 P 1 S 3 MRID 41297901

Physical and Chemical Properties

Molecular weight 288.4 MRID 41297901

Physical state Clear liquid MRID 410495 02 (Acceptable)

Vapor pressure 3.16 x 10

- 4 mm Hg (25 o C)

6.98 x 10

- 4 mm Hg (35 o C)

12.4 x 10

- 4 mm Hg (45 o C) MRID 410495 02 (Acceptable)

Henry’s Law constant 2. 22E

- 05 atm m 3 /mol USEPA, 2009

### 6 Property Value Source (Classification)

Specific gravity/density 1.11g/ml @ 20 o C MRID 410495 02 (Acceptable)

Solubility in water 5.4 mg/L @ 25 o C in distilled water 5.6 mg/L in water solution buffered at pH 7 4.5 mg/L in water solution buffered at pH 10 MRID 410495 02 (Acceptable)

log K
ow 4.71 MRID 410495 02 (Acceptable)

Laboratory accumulation in fish bioaccumulation factor (BCF) ( Lepomis macrochirus ) 320X in edible tissues

940X non

- edible (viscera) tissues

680X whole fish

At the end of the 14

- day depuration period, the reduction in residues was 84% for edible tissue, 93% for whole fish, and 9 3%for visceral tissue

. MRID 41373606

and 41773605 (Acceptable)

Environmental Fate Properties

Hydrolysis half

- life pH = 4 pH = 7 pH = 9

pH = 5

pH = 7

pH = 9 11.2 days (SFO) @ 25 ° C 11.4 days (SFO) @ 25 ° C 13.1 days (SFO) @ 25 ° C

2.52 days (SFO) @ 20 ° C [1.8 days (SFO) @ 25 ° C] 2

2.17 days (SFO) @ 20 ° C [1.5 days (SFO) @ 25 ° C] 2

2.56 days (SFO) @ 20 ° C [1.8 days (SFO) @ 25 ° C] 2

Major Degradate

Formalde hyde (Max 96.1% @ day 1.6; pH 9.0) MRID 00087694 (Acceptable)

MRID 44862501 (Acceptable)

Photolysis half

- life in air 0. 53 hours (12 hour day; 1.5E6 OH/cm 3 ) EPISUITE4. 1 1

Photolysis half

- life in water 1.77 days (SFO) @ 25 ° C

Major Degradate Formaldehyde (Max 71.9% @ day 6) MRID 00161567

and 41181101 (Supplemental)

Aerobic soil metabolism half

- life (25 °C ) 5.85 days (silt loam) (SFO) @ 25 °C 10.2 days (silt loam) (SFO) @ 25 °C

Major Degradates

Terbufos Sulfoxide (Max 52.3 % @ day 30) Terbufos Sulfone (Max 20.1 % @ day 60)

CO 2 ( Max 46 % @ day 365) MRID 00156853

and 41749801 (Acceptable)

### 7 Property Value Source (Classification)

Anaerobic soil metabolism half

- life 67.5 days (Silt loam) (SFO) @ 25 °C

Volatile organic residue 38.6% @ day 60

Major degradates Terbufos Sulfoxide (Max 10.5% @ day 15)

CO 2 (Max 53 % @ day 60) MRID 41749801 (Acceptable)

Aerobic aquatic metabolism half

- life for total system Total System

Loam sediment 24.2 days (IORE (20±2°C) [19.7days (IORE) @ 25 ° C] 2

Sand Sediment [3.66 days (SFO) @ (20±2°C)] 3 [2.6 days (IORE) @ 25 ° C] 2 ,3

Volatile organic residue ( 41.5% @ day 30 )

Major degradates Terbufos Sulfoxide (Max 11% @ day 100)

CO 2 (Max 53 % @ day 100) MRID 44672004 (Supplemental)

Aerobic aquatic metabolism half

- life in aqueous phase (natural pond water) 0.762 days (IORE) @ 20±2°C [0.6 days (IORE) @ 25 ° C] 2

1.03 days (SFO) @ 20±2°C [0.8 days (IORE) @ 25 ° C] 2

Major Degradate Degradate A (unidentified) (Max 33.8% @ day 2)

CO 2 (Max 43.6% @ day 30) MRID 44862502 (Supplemental)

Soil adsorption coefficient

K d (L/kg) Adsorption 4

K d (L/kg) 5.42 (AR Loamy sand)

11.4 ( IN Silt loam) 13.0 (NJ Sandy loam) 14.6 (WI Loam) MRID 41373604 (Acceptable)

Terrestrial field dissipation half

- life 6.01 days (IORE) in Arcola, IL

56.8 days (IORE) in Greeley, CO

22.2 days (IORE) in Hanford, CA

No major degradate s were reported MRID 00087708 (Acceptable)

MRID 00087706 (Acceptable)

MRID 418831 0 1 (Supplemental)

1 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm

2 DT 50 s values are Arrhenius

- adjusted temperature @ 25°C for exposure model inputs

. 3 DT 50 s values are recommended

. DT 50s model inputs from the k inetic guidance

. 4 Since the correlation (r 2 ) between organic carbon and K d is 0.33, Koc is not appropriate for terbufos

.

### 8 3.2 Terbufos Degradates

Three major degradates

, excluding CO 2 

### , were identified in the environmental fate studies:

terbufos sulfoxide (maximum 52.3%) , formaldehyde (maximum 96.1%) , and terbufos sulfone (maximum 20.1%) . Limited data are available on persistence and mobility for the degradates terbufos sulfoxide and terbufos sulfone ( Table 3 ). Terbufos sul foxide and terbufos sulfone have

low K d 

### values ranging from 0.40 to 2.93 mL/g and DT 50s 

### of 136 to 174 days in soil. These values suggest that these degradates are more mobile and persistent than terbufos in the environment. Terbufoxon, terbufoxon sulfoxid e, terbufoxon sulfone, des

- ethyl terbufos

sulfoxide

, and des

- ethyl terbufos sulfone were also observed and formed less than 3.1% in

environmental fate studies. The oxons (terbufoxon, terbufoxon sulfoxide, terbufoxon sulfone) were only identified in the an aerobic soil metabolism study and only as minor degradates

. Although oxon degradates are more toxic than some organophosphates, ecological structure activity r elationship ( ECOSAR ) toxicity estimates suggest that terbufos oxons are orders of magnitude less toxic than terbufos to fish and invertebrates and about an order of magnitude less toxic to algae (USEPA, 2013). Therefore, the oxons were not considered degradates of concern given the anticipated low exposure and the estimated toxicity compared to terb ufos

. Structures and percent formation of degradation product s in various environmental fate studies are provided

in Appendix B

.

Table 3 . Physical, Chemical and Environmental Fate Properties of Terbufos S ulfoxide and

Terbufos Sulfone

Property Value Source (Classification)

Terbufos Sulfoxide

Common name Terbufos Sulfoxide MRID 4 4 862501

CAS Registry No. 10548

- 10

- 4

Chemical name (CAS) S

- [[(1,1

- dimethylethyl)sulfinyl]methyl]O,O

diethylphosphorodithioate

SMILES notation CCOP(=S)(OCC)SCS(=O)C(C)(C)C EPISUITE 1

Synonyms CL 94301, AC 94301 MRID 41373604

and 4 4 862501

Structure EPISUITE 1

### 9 Property Value Source (Classification)

Molecular formula C 9 H 21 O 3 P 1 S 3

Molecular weight 304.42

Vapor pressure 3.42 E

- 05mm Hg (25 o C)

Henry’s Law constant 9.13E

- 08 atm m 3 /mol

S olubility in water 1100 mg/L @ 20 o C in distilled water

log K
ow 2.21

Hydrolysis half

- life pH = 5

pH = 7

pH = 9 33.2 days (SFO) @ 40 ° C [93.9 days (SFO) @ 25 ° C] 2

23.2 days (SFO) @ 40 ° C [65.1 days (SFO) @ 25 ° C] 2

18.5 days (SFO) @ 40 ° C [13.3 days (SFO) @ 25 ° C] 2 MRID 44862501 (Acceptable)

Aerobic soil metabolism half

- life (25 °C) 136 days (Silt loam) (SFO) @ 25 °C MRID 00156853 (Acceptable)

Soil adsorption coefficient

K d (L/kg) Adsorption 3

K d (L/kg) 0.4 (AR Loamy sand)

2.83 (IN Silt loam) 0.50 (NJ Sandy loam) 0.75 (WI Loam) MRID 41373604 (Acceptable)

Terbufos Sulfone

Common name Terbufos Sulfone MRID 4 4 862501

CAS Registry No. 56070

- 16

- 7

Chemical name (CAS) S

- [[(1,1

- dimethylethyl)sulfonyl]methy l]O,O

diethylphosphorodithioate

SMILES notation C(C)(C)(C)S(=O)(=O)CSP(=S)(OCC)OCC EPISUITE 1

Synonyms CL94320, AC 94320 MRID 41373604

and 4 4 862501

### 10 Property Value Source (Classification)

Structure EPISUITE 1

Molecular formula C 9 H 21 O 4 P 1 S 2

Molecular weight 320.42

Vapor pressure 7.88 E

- 06 mm Hg (25 o C)

Henry’s Law constant 4.10E

- 08 atm m 3 /mol

Solubility in water 408 mg/L @ 19 ° C

log K
ow 2.48

Hydrolysis half

- life

pH = 5

pH = 7

pH = 9 21.2 days (SFO) @ 40 ° C [60.0 days (SFO) @ 25 ° C] 2

15.5 days (SFO) @ 40 ° C] [43.8 days (SFO) @ 25 ° C] 2

14.7 days (SFO) @ 20 ° C] [10.4 days (SFO) @ 25 ° C] 2 MRID 44862501 (Acceptable)

Aerobic soil metabolism half

- life 174 days (Silt loam) (SFO) @ 25 °C MRID 00156853 (Acceptable)

Soil ad sorption coefficient

K d (L/kg) Adsorption 3

K d (L/kg) 0.55(AR Loamy sand)

2.93 ( IN Silt loam) 0.69 (NJ Sandy loam) 0.86 (WI Loam) MRID 41373604 (Acceptable)

1 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm

2 DT 50 s values are Arrhenius

- adjusted temperature @ 25°C for exposure model inputs

. 3 Since the correlation (r 2 ) between organic carbon and K d is ≤ 0.66, the Koc is not appropriate for terbufos

sulfoxide and terbufos sulfone

.

### 11 IV. Summary of Ecological Effects

Terbufos is moderately to very highly acutely toxic to both aquatic and terrestrial animals based on available toxicity studies. In general, studies with end use products show similar toxicity to

the technical grade active ingredient ( TGAI ) although in so me cases organisms may be slightly more sensitive to end use products. Registrant submitted toxicity studies are not available for degradation products; however, submitted ancillary information about terbufos sulfone and terbufos sulfoxide toxicity to Dap hnia magna is discussed below in addition to data identified in the ECOTOXicology database. Available data indicate similar toxicity of terbufos, terbufos sulfone, and terbufos sulfoxide.

Toxicity endpoints and values used to calculate RQs are reported i n Table 4 . All available studies including additional details are provided in Appendix C

. A summary of available data

follows Table 4

. Studies identified in the ECOTOXicology database that reported a more sensitive endpoint were reviewed and are also di scussed below. Finally, toxicity data for mixtures (i.e., terbufos plus at least one other pesticide) were identifie d in the ECOTOXicology

database. The majority of those studies show that terbufos enhances the toxicity of herbicides to terrestrial plant s. Mixture data are summarized below and additional details are provided in Appendix D

.

Table 4 . Terbufos Toxicity Endpoints and Values Used for RQ Calculations

Species Exposure

Scenario % AI Toxicity MRID

Bluegill sunfish ( Lepomis

macrochirus ) 96 hr (static) 86 LC 50 = 0.77 (0.72

- 0.83) 1 μg ai/L 00087718

ELS NA NOAEC = 0.10 μg ai/L

Estimate based on acute

- to

- chronic ratio using

rainbow trout data 2 NA

Waterflea (Daphnia magna) 48 hr (static) 88.6 EC 50 = 0.17 (0.15

- 0.19) 1 μg ai/L 00101495

21 day Life

Cycle (flow

through) 98.4 NOAEC = 0.030 μg ai/L

LOAEC = 0.076 μg ai/L based on growth and reproduction (reduced body length and number of offspring) 00162525

Sheepshead minnow ( Cyprinodon variegatus ) 96 hr 98.4 LC 50 = 1.6 (0.77

- 3.2) 1 μg ai/L 00162524

ELS NA NOAEC = 0.14 μg ai/L

Estimate based on acute

- to

- chronic ratio using

rainbow trout data 2 NA

Mysid shrimp ( Americamysis

bahia ) 96 hr (static) 98.4 LC 50 = 0.22 (0.14

- 0.35) 1 μg ai/L 00162523

NA NA NOAEC = 0. 0 41 μg ai/L

Estimate based on acute

- to

- chronic ratio using daphnia data 2 NA

### 12 Species Exposure

Scenario % AI Toxicity MRID

Freshwater Algae ( Pseudokirchneriella subcapitata) 96 hr (static) 89.3 EC 50 >1.85 mg ai/L

NOAEC = 0.399 mg ai/L

LOAEC = 1 mg ai/L based on effects to cell density, area under the growth curve, average specific growth rate, and yield. 48689902

Duckweed (Lemma gibba ) 7 day 89.3 EC 50 > 4.20 mg ai/L

NOAEC = 0.280 mg ai/L

LOAEC = 0.630 mg ai/L based on frond number, growth rate of frond number, and yield of frond

number 48689901

Northern Bobwhite Quail ( Colinus virginianus ) Single oral

dose 89.6 LD 50 =28.6 (22.2

- 55.9) 1 mg ai/kg bw 00106551

8 days (5 days

treatment and 3 days observation) 86 LC 50 = 143 (103

- 214) 1 ppm ai 00087717

Mallard Duck ( Anas platyrhynchos ) Single oral

dose 15 LD 50 = 88 (0

- 215) 1 mg formulation/kg bw

LD 50 =13.2 (0

- 32.3) 1 mg ai/kg bw 40660705

One

generation Reproduction Study 89.6 NOAEC = 5 ppm ai

LOAEC = 15 ppm ai based on a possible biologically significant (but not statistically significant) effect on embryo viability. 00161574

Brown

- headed

Cowbird ( Molothrus ater ) Single oral

dose 20 LD 50 = 85 (46

- 151) 1 mg formulation/kg bw

LD 50 = 16.9 (9.2

- 30.1) 1 mg ai/kg bw 41508804

Rat Acute Oral 89.7 LD 50 = 1.25 (0.98

- 1.52) 1 mg ai/kg bw (female) 44021601

19 LD 50 = 0.836 mg ai/kg bw (female) 47512801

2

- generation reproduction 89.6 NOAEC (L) = 1 ppm ai (0.07

- 0. 0 9 mg ai/kg bw/day)

LOAEC (L) = 2.5 ppm ai (0.18

- 0.24 mg ai/kg bw/day) based on decreased pregnancy, decreased male fertility, decreased body weight gain in adult females during lactation, and decreased pup weights 43649402

Honeybee ( Apis mellifera ) Acute contact T GAI LD 50 = 4.09 μg ai/bee 00066220

Cabbage, Carrot, Cucumber, Lettuce, Soybean, Tomato, Corn, Oat, Onion, Ryegrass Tier 1 Seedling Emergence 89.3 EC 25 >2.04 lb ai/A

NOAEC = 2.04 lb ai/A

Applies to monocots and dicots 48710801

1 Range is 95% confidence interval.

2 See Table C

- 1

, Appendix C , for calculations. ELS = Early life stage ; NA = not applicable

### 13 4.1 Aquatic Organisms

Acute Toxicity to Freshwater Fish

TGAI

Several acute toxicity studies with different species are available. Toxicity may be underestimated because the available studies reported nominal concentrations and terbufos may degrade by hydrolysis and photolysis during a 96 hr e xposure period. Bluegill sunfish is the most sensitive species tested with acute toxicity ranging from 96 hr LC 50 

### = 0.77 to 3.8 μg ai/L (MRID 00037483, 00085176, 00087718, and 40098001). Rainbow trout acute toxicity ranged

from 96 hr LC 50 

### = 7.6 to 9.4 μg ai/L (MRID 00037483 and 40098001). Fathead minnow

showed a 96 hr LC 50 

### = 390 μg ai/L (MRID 40098001). Brown trout showed a 96 hr LC 50 

### = 20 μg ai/L (MRID 00087718 ). Channel catfish showed a 144 hr LC 50 

### = 9.6 μg ai/L (MRID

00085176 ). Sublethal effects in cluded partial loss of equilibrium and pectoral fin erection; however, it is not clear if these effects were observed in surviving fish or fish that eventually died and most studies did not report any sublethal effects.

End use product

The 15% granular formulation of terbufos (Counter 15G) is comparable in acute toxicity to technical grade terbufos. The 96 hr LC 50 

### = 1.8 (95% confidence interval of 1.5

- 2.3 ) μg ai /L for bluegill sunfish and the 96 hr LC 50 

### = 8.9 μg ai /L (95% confidence interval of 7.2

- 11.1 ) for rainbow trout (MRID FE0TER04 and FE0TER05). Sublethal effects were not reported for surviving fish.

A second study with a 15% granular formulation of terbufos (product not specified) showed similar results (MRID 40098001) for toxicity to rainbow tr out and blugill sunfish. The 96 hr

LC 50 

### = 1.7 (95% confidence interval of 1.2

- 2.4) μg ai/L for bluegill sunfish and the 96 hr LC 50 

### = 8.8 μg ai/L (95% confidence interval of 6.4

- 12.1) for rainbow trout. Data were also reported for fathead minnow (96 hr LC 50 

### = 150; 95% confidence interval of 101

- 223 μg ai/L) and channel catfish (96 hr LC 50 

### = 1800; 95% confidence interval of 1230

- 2640 μg ai/L). Sublethal effects were not reported.

Chronic Toxicity to Freshwater Fish

An early life

- stage study with rainbow trout (MRID 41475802) showed reduced wet weight and length at concentrations 1.4 μg ai/L and higher . A significant reduction of 60 day post hatch

survival was observed at concentrations of 2.7 μg ai/L and higher. A majority of fish at 2.7 and 5.3 μg ai/L showed sublethal effects throughout the study including resting on their lateral surfaces, hypersensitivity, loss of equilibrium, irregular respiration, dark discoloration, surfacing, and quiescence. In addition, se veral fish in various concentrations developed spinal curvature and malformed otic capsules. The study NOAEC = 0.64 μg ai/L.

A second study with rainbow trout (MRID 40009301) did not produce a NOAEC because no effects were observed at the highest test co ncentration (1.4 μg ai/L).

### 14 In addition to the available registrant submitted studies, an open literature study (Call et al.

, 1989) was identified in the ECOTOXicology database that reported a more sensitive endpoint; therefore, the study was reviewed. Th e NOAEC = 0.34 μg ai/L and the LOAEC = 0.56 μg ai/L based on reduced length of juvenile fathead minnows ( Pimephales promelas ) . Wet weight was reduced at higher test concentrations. The study authors questioned the biological significance

of the observed effects (5

- 5.5% reduction) and set the study NOAEC at 1.96 μg ai/L. T he study was classified as qualitative in part because of high variability in measured test concentrations

. Therefore, results are not used to calculate RQ values but are incorporated i nto the risk

characterization.

Bluegill sunfish sensitivity to terbufos on a chronic basis was estimated using an acute to chronic ratio (ACR) because it is the most acutely sensitive species. The ACR was based on rainbow trout (acute and chronic toxicit y) and bluegill sunfish (acute toxicity) data (see Table C

- 1 in Appendix C for calculation). The estimated NOAEC = 0.10 μg ai/L

Chronic Toxicity to Aquatic

- phase Amphibians

One open literature study on aquatic

- phase amphibians was identified in the ECOTOXicology database. Fish are typically used as surrogates for aquatic

- phase amphibians; however, this study was reviewed because under

- represented taxonomic classes including aquatic

- phase amphibians have been selected for further refinement in prelim inary risk assessments

, even if these taxa show less sensitivity than surrogate species. The southern bellfrog showed delayed development (Gosner stage) and metamorphosis when exposed to 10 μg terbufos sulfone/L (nominal) for ten weeks (Choung et al.

, 201 1a ). T erbufos was not tested. The study was classified as qualitative in part because only one terbufos sulfone concentration was tested ; thus

, an evaluation of dose

- response cannot be determined

. Therefore, results are not used to calculate RQ values b ut are incorporated into the risk characterization.

Acute Toxicity to Marine/Estuarine Fish

Two acute toxicity studies are available for sheepshead minnow. Toxicity ranged from 96 hr

LC 50 

### = 1.6 to 3.2 μg ai/L (MRID 00162524 and 41373602) . Sublethal e ffects were observed in both studies and included loss of equilibrium, floating at the surface, forward pointing pectoral fins, erratic swimming, labored respiration, quiescence, fish at the bottom of the test chamber, and surfacing.

Chronic Toxicity to Marine

- Estuarine Fish

No data are available for the chronic toxicity of terbufos to estuarine/marine fish. Therefore, a

NOAEC for estuarine/marine fish of 0.14 μg/L was calculated using the acute toxicity endpoint for sheepshead minnow and an ACR for freshwater fish (i.e., rainbow trout) (see Table C

- 1 in Appendix C for calculation)

.

### 15 Acute Toxicity to Freshwater Invertebrates

TGAI

Daphnia magna is the most sensitive species tested with acute toxicity ranging from 48 hr LC 50 

### = 0.17 to 0.4 μg ai/L (MRID 00101495 and 40098001); the majority of individuals displaying sublethal effects (erratic swimming and lying on the bottom) w ere deceased by 48 hours. Gammarus pseudolimnaeus showed a 96 hr LC 50 

### = 0.2 μg ai/L (MRID 40098001). Chironomus plumosus showed a 48 hr LC 50 

### = 1.4 μg ai/L (MRID 40098001). Crayfish showed a 96 hr LC 50 

### = 8 μg ai/L (MRID 00085176 ); sublethal effects were not reported for surviving individuals.

In addition to the available registrant submitted studies for freshwater invertebrates, two open

literature studies were identified in the ECOTOXicology database that reported a more sensitive endpoint. B oth studi es were classified as qualitative (described below) ; t herefore, the results are not used to calculate RQ values but are incorporated into the risk characterization.

The freshwater invertebrate, Ceriodaphnia cf dubia , showed a 48 hr EC 50 

### = 0.121 to 0.142 μg ai/L and a 96 hr EC 50 

### = 0.074 to 0.078 μg ai/L (Choung et al. , 2011b). The ranges represent the

EC 50 

### value s from two independent tests. A second set of experiments was conducted that reported only 96 hr EC 50 

### values; these values were similar to those from the first set of experiments. Sublethal effects were not reported. The study also reported on toxicity of degradation products (discussed below) and pesticide mixtures (discussed below). The study was classified as qualitative because exposure c onc entrations were not reported and exposure concentrations were not verified by analytical measurement with exception of the highest test

concentration.

Gammarus pseudolimnaeus showed a range of 96 hr LC 50 

### s from 0.08 to 1.24 μg ai/L ( Howe et
al. , 1994 ) base d on a range of pH (6.5

– 9.5) and temperature (7 to 17°C) conditions. Toxicity (LC 50 

### = 0.17 μg ai/L) was esentially the same as that observed in MRID 40098001 (LC 50 

### = 0.20 μg ai/L; 95% confidence interval = 0.1

- 0.3 μg ai/L) under the same conditions (pH 7.4

– 7.5 and 17°C). At 96 hr, toxicity tended to increase with increasing temperature and change in pH away

from near neutral ( i.e., 7.5). However, overall there was not a statistically significant effect of pH on toxicity. Similarly, there was no difference in toxicity at 12 and 17°C; however, toxicity at those temperatures was significantly greater than that at 7°C. Sublethal effec ts were not reported. The study was classified as qualitative for various reasons including but not limited to questions about control mortality, exposure concentrations were not reported , and e xposure concentrations were not verified by analytical measur ement with exception of the highest and lowest test concentration at the beginning of the experiment.

End Use Product

The 15% granular formulation of terbufos (Counter 15G) is comparable in acute toxicity to technical grade terbufos. The 48 hr LC 50 

### = 0. 9 (95% confidence interval of 0.8

- 1.2 ) μg ai /L for Daphnia magna (MRID FE0TER06). Sublethal effects were not reported.

### 16 Chronic Toxicity to Freshwater Invertebrates

A 21

- day life cycle study with Daphnia magna (MRID 00162525) showed reduced body length

and number of offspring at 0.076 μg ai/L, the highest test concentration . The NOAEC = 0.030 μg ai/L. Daphnids, some of which may have later died, were observed lying on the bottom or quiescent toward the end of the experiment (day 19 and 21).

Degradation Products

Several sources of information suggest that terbufos sulfoxide and terbufos sulfoxone are similar

to terbufos in their acute toxicity to aquatic invertebrates.

Toxicity studies are not available; however, the registrant submitted information about the toxicity of terbufos sulfone and terbufos sulfoxide to Daphnia magna based on a screening study (MRID L000037). The registrant reported a 48 hr EC 50 

### = 1 μg ai/L fo r terbufos sulfone and the

48 hr EC 50 

### = 2.1 μg ai/L for terbufos sulfoxide. No sublethal effects were reported. The information is taken at face value and suggests that the degradates are similar to terbufos in acute toxicity.

In addition to the availab le registrant submitted information, there are two open literature studies that reported toxicity of terbufos sulfoxide and terbufos sulfone in comparison to terbufos. One study reported toxicity to Ceriodaphnia cf dubia (Choung et al. , 2011b; discussed a bove).

Terbufos sulfoxide showed a 48 hr EC 50 

### = 0.489 to 0.594 μg ai/L and a 96 hr EC 50 

### = 0.360 to

0.363 μg ai/L . Terbufos sulfone showed a 48 hr EC 50 

### = 0.324 to 0.381 μg ai/L and a 96 hr EC 50 

### = 0.148 to 0.222 μg ai/L . The ranges represent the EC 50 

### valu e from two independent tests.

These values are within a factor of 5x of the terbuf os toxicity observed in concurrently

conducted studies

. A second and third set of experiments were conducted that reported only 96

hr EC 50 

### values; these values were similar to those from the first set of experiments. No sublethal effects were reported.

The second study reported toxicity to Chironomus tepperi (Choung et al.

, 2010). There was not a statistically significant difference in the toxicity of terbufos, terbufos sulfoxide, and terbufos sulfone. Toxicity of the three compound s differed less than a factor of 2x. Terbufos showed a

96 hr EC 50 

### = 1.99 to 2.27 μg ai/L, t erbufos sulfoxide showed a 96 hr EC 50 

### = 3.53 to 3.74 μg ai/L, and terbufos sulfone showed a 96 hr EC 50 

### = 2.49 to 2.69 μg ai/ L

. The ranges represent the

EC 50 

### value from two independent tests. A second set of experiments was conducted that reported 96 hr E C 50 

### values that were similar to those from the first set of experiments. No sublethal effects were reported.

Acute Toxicity to Marine/Estuarine Invertebrates

In three 96 hr acute toxicity studies with mysid shrimp

, the LC 50 

### ranged from 0.22 to 0. 54 μg ai/L (MRID 00162523

, 41297903

, and 42306701 ). The two older studies showed excessive control mortality (more than 10%). One, a static test (MRID 00162523)

, showed 20% mortality in the negative control but 0% in the solvent control. The other, a flow

- through test (MRID 41297903)

, showed 5% mortality in the negative control but 15% in the solvent control (the

### 17 study author indicated that dead organisms were not located and suggested that the loss was due to misplacement of organisms during transfer between vessels at test initiation). Although the control mortality raises questions about the toxicity values of the older studies , the three studies

show consistent results under different exposure conditio ns (static vs. flow

- through) with LC 50 

### values differing by only 2.5X. Sublethal effects included quiescence, lying on the bottom, surfacing, loss of equilibrium , erratic swimming, gyrating motions, and lethargy

.

Easter n oyster ( Crassostrea virginica ) showed a 96 hr EC 50 

### = 201 μg ai/L (MRID 42381501 ).

Chronic Toxicity to Marine

- Estuarine Invertebrates

No data are available for the chronic toxicity of terbufos to estuarine/marine invertebrates. Therefore, a chronic toxicity endpoint for estuarine/marine invertebrates of 0. 041 μg/L was

calculated using the acute toxicity endpoint for mysid shrimp and an ACR for freshwater invertebrates (i.e., Daphnia magna ) (see Table C

- 1 in Appendix C for calculation)

.

Aquatic Plants

Two toxicity studies are available for non

- vascular plants. A study with a freshwater green algae

showed a 96 hr EC 50 

### >1.85 mg ai/L (MRID 48689902). The NOAEC = 0.399 mg ai/L and the LOAEC = 1.00 mg ai/L based on reduced cell density, area under the growth curve, average specific growth rate, and yield. A study with a marine di atom showed a 96 hr EC 50 

### >1.01 mg ai/L and the NOAEC ≥ 1.01 mg ai/L (MRID 48939101). Statistically significant adverse effects were not observed in this study. Although this study had guideline deviations that likely

confounded the results ( e.g. , excessi ve variation in initial cell density) , the study is sufficient to indicate that there is likely no inhibition within the range of concentrations tested. Data are not available for freshwater diatom or bluegreen algae species.

In addition to the available registrant submitted studies for non

- vascular aquatic plants, an open literature study (Tien and Chen, 2012) was identified in the ECOTOXicology database that reported a more sensitive endpoint for non

- vascular aquatic plants. The freshwater diatom,

Nitz schia sp, showed a 96 hr EC 50 

### = 0.59 to 1.51 mg ai/L. Two other test species showed less sensitivity: Oscillatoria sp. (96 hr EC 50 

### = 7.99 mg ai/L) and Chlorella sp. (96 hr EC 50 

### = 41.16 mg ai/L). The study was classified as qualitative in part because of a lack of information about growth in the controls . Therefore, the results are not used to calculate RQ values, but are incorporated into the risk characterization.

A vascular plant study with duckweed showed an EC 50 

### > 4.20 mg ai/L (MRID 48689901). The NOAEC = 0.280 mg ai/L and the LOAEC = 0.630 mg ai/L based on frond number, growth rate of frond number, and yield of frond number. Inhibition was observed at higher concentrations

for ar ea under the curve and biomass.

### 18 4.2 Terrestrial Organisms

Acute Oral Toxicity to Birds

TGAI

The acute oral LD 50 

### = 28.6 (22.2

- 55.9; 95% confidence interval) mg ai/kg bw for bobwhite quail (MRID 00106551 ) when exposed to the TGAI. Observed sublethal effects included lethargy progressing to depression, reduced reaction to external stimuli, loss of coordination, lower limb weakness, prostrate posture, loss of righting reflex, salivation, and lower limb rigidity.

Three open literature studies identified in the ECOTOXicology database reported a more sensitive endpoint. Bobwhite quail showed acute oral toxicity ranging from a n LD 50 

### = 15 (95%

confidence interval = 12

- 19 and slope = 7.9) (Hill and Camardese, 1984) to 24.4 (95%

confidence interval = 18.1

- 31.8 and slope = 5.1) mg ai/kg bw (Brewer et al. , 1996). Observed

sub lethal effects reported by Brewer et al. (1996) were consistent with those reported in other studies: all dosed birds exhibited lethargy, wing droop, piloerection and diarrhea whereas birds receiving higher doses were ataxic and prostrate prior to death. Wolfe and Kendall (1998) examined toxicity of different age classes of red

- winged blackbirds and starling; in general both species showed increasing LD 50 

### s with increasing age. Adult red

- wing ed blackbirds showed an

LD 50 

### = 2.06 (95% confidence interval = 1. 52

- 3.53) mg ai/kg bw and nestlings (0

- 11 days old) showed sensitivity ranging from an LD 50 

### = 0.36 to 3.33 mg ai/kg bw. Starlings were less

sensitive: adults showed an LD 50 

### = 204 (95% confidence interval = 130

- 350) mg ai/kg bw and nestlings (0

- 19 days old) showed sensitivity ranging from an LD 50 

### = 2.3 to 60.8 mg ai/kg bw.

Red

- winged blackbird nestlings showed behaviors such as failure to beg, vocalize, and respond to parental stimulation and some of thos e birds were thrown out of the nest. The study also reported reduced plasma and brain cholinesterase activity from exposure to terbufos. The three open literature studies were classified as qualitative for various reasons including but not limited

to: (a ) a general lack of details about experimental design (Brewer et al. , 1996)

, (b) limited dose

levels were tested for red

- winged blackbirds, dose levels were not reported (range only) or verified by analytical measurement, and there was a loss of birds due to illness or escape at dosing (Wolfe and Kendall, 1998)

, and (c) dose levels were not reported or verified by analytical measurement (Hill and Camardese, 1984 ) . Therefore, results are not used to calculate RQ values but are incorporated into the risk cha racterization.

End Use Product

Results for formulated product testing also show that terbufos is highly toxic to birds on an acute oral basis (M RI D 40660705, 40660706, 40660707, 40660708

, 41508802, 41508803, 41508804,

and 41508805 ). The product Counter 15G showed an LD 50 

### = 43.5

- 44.3 mg ai/kg bw ( 290

- 295 mg formulation/kg bw) 1 

### for bobwhite quail, an LD 50 

### =13.2 mg ai/kg bw (88 mg formulation/kg bw) for mallard duck , and an LD 50 

### = 22.2 mg ai/kg bw (148 mg formulation/kg bw) for brown

headed cowbird

. Although greater sensitivity was not observed (TGAI vs TEP tested in the same study) , it is noted that Hill and Camardese (1984)

, as discussed above, tested bobwhite quail with

Counter 15G and showed an LD 50 

### = 26 mg ai/ kg bw

. The product Counter CR showed an LD 50

1 Range based on two studies.

### 19 = 47.6 mg ai/kg bw (238 mg formulation/kg bw) for bobwhite quail and an LD 50 

### = 16.9 mg ai/kg bw (85 mg formulation/kg bw) for brown

- headed cowbird. The product Counter 20P showed an

LD 50 

### = 50 mg ai/kg bw (250 mg formulation/kg bw) for bobwhite qu ail and an LD 50 

### = 32.2 mg ai/kg bw (161 mg formulation/kg bw) for mallard duck. Sublethal effects observed in these studies are consistent with those observed in response to oral dosing with the TGAI (see Appendix C for details by study).

Acute Dietary T oxicity to Birds

Bobwhite quail is the most sensitive species tested on an acute dietary basis with an LC 50 

### = 143 (125

- 201; 95% confidence interval) ppm ai (MRID 00087717) and 157 ppm ai (103

- 214 ; 9 5% confidence interval) ppm ai ( MRID 00160387)

– both ba sed on nominal test concentration. Bobwhite quail showed decreased locomotor activity, feather erection, loss of righting reflex, depression (lethargy), reduced reaction to sound and movement, wing droop, loss of coordination, prostrate posture, lower lim b rigidity, ruffled appearance, lower limb weakness, reduced body weight gain, and reduced food consumption.

Mallard duck was tested on an acute dietary basis and showed an LC 50 

### = 153 ( 117

- 198; 95%

con fidence interval ) ppm ai (MRID 00087717) and 697 ppm ai ( 584

- 1616; 95 % confidence interval) ppm ai (MRID 00035120)

– both based on nominal test concentrations. Mallard ducks showed decreased locomotor activity, feather erection, loss of righting reflex, reduced body weight, and reduced food consumption.

Ch ronic Toxicity to Birds

Available studies do not clearly define a NOAE C . Studies with bobwhite quail and mallard duck (MRID 00097892 and 00085177) showed possible effects on viable embryos of eggs set at 2 ppm ai. Mallard duck also showed decreasing bod y weight at both 2 and 20 ppm ai throughout the study in contrast to the control birds

, which gained weight. However, t he results of these studies cannot be confirmed due to a lack of pen by pen data.

A second study with mallard duck showed a possible NOAE C = 5 ppm ai based on an effect (not statistically significant) on embryo viability at 15 ppm ai (MRID 0161574). A second study with bobwhite quail showed no effects at 30 ppm ai, the highest test concentration tested (MRID 00161573).

Phorate, the closest chemical analog to terbufos, showed a NOAE C = 5 ppm ai for mallard duck (MRID 00158334 ). The sub acute dietary toxicity of phorate to m allard duck ( LC 50 

### = 240 ppm ai, MRID 00022923) is also similar to the toxicity of terbufos. Given th at a NOAE C i s not clearly defined for terbufos

, an approximate NOAEC of 5 ppm ai is assumed based on the

combined information from the available terbufos and phorate studies. Risk conclusions would not change if the NOAE C w as lower than 2 ppm ai as suggested by the s tudy results that could

not be confirmed ( MRID 0097892 and 00085177 )

.

### 20 Acute Oral Toxicity to Mammals

TGAI

The acute oral LD 50 

### = 1.25 (0.98

- 1.52; 95% confidence interval) mg ai/kg bw for female rats (MRID 44021601 ) when exposed to the TGAI. Observed sublethal effects included tremors, salvation, exophthalmos (bulging of the eye) , and decreased activity. All survivors appeared normal 9 days after dosing.

End Use Product

Results for formulated product testing a lso show that terbufos is very highly toxic to mammals on an acute oral basis (MIRD 47512801) and that the 20G formulation is slightly more toxic tha n the TGAI . The product Counter 20G showed an LD 50 

### = 0.836 mg ai/kg bw for female rats (confidence interva ls could not be calculated)

.

Chronic Toxicity to Mammals

A 2

- gener a tation reproduction study with rats showed a NOAEC (L) = 1 ppm ai (0.07

- 0. 0 9 mg ai/kg bw/day) for maternal/offspring and reproductive effects (MRID 43649402). The

LOAEC (L) = 2.5 ppm ai (0.18

- 0.24 mg ai/kg bw/day) based on decreased pregnancy rate

, decreased male fertility, decreased body weight gain in adult females during lactation, and decreased pup weights. Cholinesterase inhibition was observed at 1 ppm ai and higher ( NOAEC = 0.5 pp m ai).

Terrestrial Invertebrates

The acute contact LD 50 

### = 4.09 μg ai/bee when exposed to the TGAI (MRID 00066220 ). Acute

and chronic oral toxicity data (adult or larvae) are not available for terbufos or phorate, the structural analog of terbufos.

Terr estrial plants

In a Tier I seedling emergence study, no statistically significant inhibition was observed in any of the ten tested species (MRID 48710801). The EC 25 

### > 2.04 lb ai/A and the NOAEC = 2.04 lb ai/A for both monocots and dicots. A vegetative v igor study is not available.

The majority of open literature studies show no effects to terrestrial plants at the tested concentrations. However, a small number show phytotoxicity effects (other than growth or survival) or reduced yield in field studies that may indicate greater sensitivity than registrant

submitted data ; thus, these studies are discussed qualitatively in the risk characterization

. Greenhouse grown corn treated at both 0.98 and 1.96 lb ai /A showed increased chlorosis (7 day old corn) and decreased tissue zinc concentration (at harvest); a NOAEC was not reported for these endpoints (Matocha and Hopper, 2001). Testing was conducted on 15G and CR formulations. Reduced chlorophyll (28 day ol d corn; 15G only) and plant height (7 day old corn) were observed for both test concentrations early in the experiment; however, both variables

### 21 showed recovery compared to the control at time points thereafter. Two field studies showed

effects of terbufos on plant yield (reduced numbers of sugar beet plants at 1.78 lb ai/A; Downard

et al. , 1999 and kenaf plants at 2 lb ai/A; Barillas

- Argueta, 1993); however, the observed effects were isolated and there is inherent uncertainty as to the cause of effects in field studies. Yield was only impacted in a single instance in either study (single year and location); kenaf was tested in two years at a single location and sugar beet was tested in two years at three different locations. In addition, Dow n ard et al. (1 999) tested both 15G and CR formulations at each location/year except the single instance that showed reduced yield . In that case

, the test material was only reported as “terbufos”. There were no additional effects on kenaf (plant diameter, height, and we ight; Barillas

- Argueta, 1993) or sugar beet (injury index, root yield, and sucrose

characteristic s; Downard et al, 1999).

4.3 Simulated and/or Actual Field Tests

Several field studies provide information on impacts to non

- target organisms following application of terbufos. Among the limitations of field studies is the issue with false negatives (i.e., the failure to identify animals impacted by exposure to terbufo s). This is in part because findings are highly dependent upon the probability of locating a dead animal on the treated field, the probability of locating a dead animal before it is removed from the treated field by a scavenger, and the probability that a moribund animal moved off the treated field by itself.

1. Terrestrial Field Study . Counter 15G applied to corn fields at 1 lb ai/A at time of plant

showed minimal acute effects on wildlife (two dead birds) ; however carcass searches, residue analyses, an d miscellaneous wildlife observations were very limited (MRID 00085178, 00085180, and 00087726).

2. Simulated Field Study, exposure to treated soil . Ring

- necked pheasants were exposed to soil treated with Counter 15G at a rate equivalent to 1 to 5 lb ai/ A and residues were not detected in soil 22 days after the initial exposure. No poisoning symptoms were observed during 55 days of observation following treatment. Two of three birds exposed to a simulated spill died within 12

hours of the initial exposure (MRID 00085179, 00085183, and FEOTEROl).

3. Terrestrial Field Study. Terbufos was applied at planting at 2.6 lb ai/A and 10 weeks later as a broadcast aerial application at 1 lb ai/A to a cornfield in Maryland. Following the at

- planting application

, several species of wildlife were observed dead (one bluebird, one morning dove , two snakes, and one turtle ) or alive and exhibiting signs of cholinergic poisoning ( one blue jay, one

robin

, and one brown

- headed cowbird )

. The affected blue jay and dead blu ebird contained

residues of 0.24 and 0.15 ppm , respectively . Seven feather spots were also found indicating a dead bird that was consumed by a predator. Following the aerial application

, surveys identified eight dead birds, one affected bird, 14 dead mamma ls (mouse, rat, woodchuck, shrew, raccoon, and rabbit) , one dead reptile, six feather spots

, one fur spot , and several dead fish

. Detectable levels of terbufos residues in the affected and dead animals ranged from 0.09 to 8.47 ppm (MRID BAOTEROl and 145854).

4. Terrestrial Field Study. Three seasons of field research were conducted from 1987 to 1989 in

south central Iowa to assess the environmental exposure of terbufos and its effects on wildlife in

a corn agro

- ecosystem. Terbufos was applied at 1. 3 lb ai/A in bands and in furrows at the time of

### 22 planting of corn. Monitoring and biochemical sampling techniques showed relatively low exposure to most species sampled. Nonetheless, mortalities were observed and individuals

showed reduced brain ChE activ ity and the presence of terbufos residues (including degradation products) in the GI tract. Results from starling nest box monitoring in the second year suggest some effects in reproduction parameters and third year passerine blood plasma ChE activity

sho wed a significant difference between in

- furrow treatment sites and controls in blue jay (MRID 40985501 and 41475801).

5. Simulated Field Study. A study was conducted to compare the effects of Counter 15G to

Counter CR on bobwhite quail and brown

- headed cowbirds. Terbufos was applied at time of corn planting in pens using band and in

- furrow applications. Despite study limitations, the results suggest that both formulations could impact non

- target wildlife species. All t reatment pens showed higher mortality rat es than controls (MRID 41508801 and 41849201).

4.4 Toxicity of Mixtures

There are not any terbufos products formulated with another active ingredient. However, numerous studies were identified in the open literature that examined the toxicity of terbufos combined with at least one other pesticide (see Appendix D )

. The majority of these studies compared the effects of pesticide mixtures on terrestrial plants , typically corn

. These experiments compared toxic effects when terbufos was applied alone to toxic effects when terbufos was applied along with common herbicides to determine if the interaction was neutral, increased toxicity (i.e., additive or synergistic effect ) or decreased toxicity ( antagonistic effect ).

It is well established that terbufos and other OP insecticides can have a synergistic interaction

with acetolactate synthase ( ALS ) inhibitor herbicides such as sulfonylureas. The majority of the reviewed studies showed that combined exposure of t erbufos and ALS inhibitor herbicides ( e.g. , nicosulfuron, primisulfuron, rimsulfuron, prosulfuron, chlorimuron, and flumetsulam) increased toxicity to plants ; however, terbufos did not increase toxicity of all ALS herbicide s ( e.g

. imazaquin) under experimental conditi ons

. Likewise, terbufos interacted with other types of herbicides including ph otosynthesis inhibitor s , growth regulator s , shoot and root growth

inhibitor s, and PPO inhibitors to increase toxicity of some herbicides ( e.g. , metribuzin, cycloate, and oryzali n ) but not others ( e.g. , atrazine, clopyralid, 2,4

- D, metolachlor, alachlor, and acifluorfen)

. In general, many factors impacted the effects of terbufos

- herbicide mixtures including but not limited to the presence of safeners, application rate, application timing, terbufos formulation and method of application, effect endpoint, and experimental site location.

A smaller number of studies tested the effects of mixtures on aquatic organisms. Increased toxicity to fish was observ ed from exposure to mixtures of terbufos with either permethrin or atrazine

. Mixtures of atrazine and terbufos increased the toxicity of terbufos to one aquatic invertebrate species ( Ceriodaphnia dubia ) but not another ( Chironomus tepperi ). The toxicity

of t erbufos sulfone and terbufos sulfoxide to aquatic invertebrates was not impacted by mixtures

with atrazine

. Similarly, there was no evidence of synergism when frogs were exposed to a mixture of terbufos sulfone and atrazine. Finally, m ixtures of ter bufos and other organophosphate chemicals (chlorpyrifos and methamidophos) showed antagonistic interactions on toxicity (decreased) to individual species ( Oscillatoria sp. and Chlorella sp.) and multi

### 23 species assemblages of algae

. In contrast, terbufos an d methamidophos may have had a synergistic interaction on the toxicity to the multi species assemblage.

4.5 Incident Information

The RED ( USEPA, 1999 ) reported that terbufos was the leading cause of fish kill incidents reported to EPA for any pesticide applied to corn and ranked fourth in fish kill incidents reported to EPA for any pesticide applied to any crop. Additional t erbufos related incidents were

obtained from the Ecological Incident Information System (EIIS, v 2.1.1 ), the Aggregate

Incident Dat a System

, and the Avian Incident Monitoring System (AIMS) 2 

### on May 19

, 201 4 3



### . Incidents occurring after 1999 are typical of those previously reported. There is not enough information provided in the incident reports to determine which if any aquatic incid ents reported after 1999 reflect mitigation efforts resulting from the RED. The reports indicate that some incidents prior to 1999 occurred despite the use of buffer strips, which were not required at that

time

. After 1999

, there were four reported incid ents with fish, two with birds, and one with

mammals in the EIIS database. Two plant damage incidents are reported in the EIIS database; however, in both cases two herbicides were applied in addition to terbufos. Previous

assessments of terbufos incident s did not include those identified in the Aggregate Incident Data System or AIMS. Both of these databases revealed incidents prior to and after the RED. Focusing on incidents since the RED

, there were five minor wildlife incidents, three bird

incidents ( not included in EIIS) , and six minor plant incidents. Unlike the EIIS database, few details are reported about incidents in the other two databases.

The majority of reported fish incidents occurred prior to the RED. There are several k ey points about the aquatic incidents reported in the EIIS database:

• The majority of incidents are associated with use on corn.

• Incidents are associated with various methods of application and two of the three granular
formulations (Counter 15G and Coun ter CR). No incidents have been reported for 20G

, which was registered more recently.

• The majority of incidents occurred in 5 corn belt states (IA, IN, IL, NE, OH).

• Incidents involve mortality from 2 0 to 90,000 fish.

• Large grassy buffer strips (3 0 0

- 1000 ft) did not prevent incidents in some cases.

• Incidents generally occurred 2 days to 3 weeks after application.

• 

### In some of the incidents, rainfall was reported as occurring over a period of days to
weeks prior to the incident. Based on the limited weather information provided, the
Agency believes the incidents could be associated with normal spring rain events, as
opposed to unusually severe rainfall events over a short period of time.



### T he updated incident list is provided in Appendix E

.

2 http://www.abcbirds.org/abcprograms/policy/ toxins /aims/aims/index.cfm

3 It was confirmed that no additional incidents were added to the EIIS or the Aggregate Incident databases between May 19, 2014 and August 25, 2015. The AIMS database was not accessible on August 25, 2015.

### 24 V. Aquatic LOC Assessment

5.1 Exposure Estimates

The Surface Water Concentration Calculator (SWCC v 1.106) model 4 

### was used to generate estimated environmental concentrations (EECs) for the Tier II aquatic exposure assessment. The SWCC is a graphical user interface that runs the Pesticide Root Zone Model (PRZM, v 5, November 15, 2006) and the Variable Volume Water Body Model (VVWM, 3/6/2014 ) (USEPA, 2006b)

. Simulations are run for multiple (usually 30) years and the EECs represent peak values that are expected once every ten years based on the thirty years of daily values generated during

the simulation. Separate EECs were generated for residues of concern: terbufos, terbufos

sulfo ne
, and terbufos sulfo xide

. The SWCC model was parameterized using relevant use and

environmental fate data for terbufos , terbufos sulfone, and terbufos sulfoxide according to the EFED input parameter guidance for water modeling (USEPA, 2009). Application rates for

terbufos sulfone and terbufos sulfoxide were determined by adjusting the application rate of

terbufos by the maximum percentage of degradate formed and the molecular weight ratio of

terbufos to the degradate

. The residue summation method (USEPA, 2008a) was used to estimate

the 1

- in

- 10 year exposure concentrations for total toxic residues (TTRs) representing the combined exposure to the residues of concern (terbufos, terbufos sulfone, and terbufos sulfoxide)

. EXCEL was used to p ost

- process estimated EECs generated for terbufos , terbufos sulfone, and terbufos sulfoxide

. One inch incorporation of granular terbufos was modeled to

represent the typical incorporation depth for all labeled application methods (in furrow, banded,

and knifed

- in).

Current terbufos labels require certain setback distances or vegetative buffers betwe en treated areas and surface water. A well maintained vegetative buffer could potentially intercept sediment

laden with terbufos via runoff from a treated field. However, the current surface water model does not have the capability to account for the pres cribed setbacks or vegetative buffer distances ; thus

, the SWCC model generated EECs are considered upper bound aquatic exposures. While there is good evidence that buffers can reduce pesticide movement into water bodies to some extent, there is still a great deal of uncertainty regarding the performance of b uffers, which

includes but is not limited to p roper design and placement and the duration of their efficacy. Many studies have been conducted to document the effectiveness of various types of vegetative buffers, commonly known as vegetative filter strips (VFS) . Based on a review of available research, EFED hypothesized that the use of VFS may reduce loading of total toxic residues of terbufos in aquatic systems by 50% to 90% ( see USEPA, 2015 for a full discussion)

.

Input parameters and representative results of SWCC modeling are provided in Appendix F

. The highest and lowest EECs based on TTR for various scenarios and application rates are provided in Table 5

.

4 http://www.epa.gov/oppefed1/models/water

### 25 Table 5. Estimated Environmental Concentrations (EECs) of Total Toxic Residue s of

Ter bufos (TTR 1

, 2 

### ) for Surface Water and Benthic Layer Based on Selected Crop Scenarios

Use

Scenario (modeled rate) Application

Method Peak EEC
( 

### μg/L ) 3 21

- DayEEC
( 

### μg/L ) 3 60

- Day EEC
( 

### μg/L ) 3

TTR in Surface Water

Corn:
MScorn_STD
ORsweetcorn_OP (1 app. X 1.30 lb ai/acre)

Ground (Incorporated) 23.40

5.52 17.00

4.95 15.50

3.63

Corn : NCcornW_OP
NCcornE_STD (1 app. X 2.6 lb ai/acre) 24.80

15.50 21.40

11.30 18.70

9.08

Sugar beet : MNsugarbeet_STD CAsugarbeetWirrg _OP (1 app. X 1.96 lb ai/acre) 14.20

9.84 8.03

8.27 6.30

6.89

Sorghum : TXsorghum_OP KSsorghum_STD (1app. X 1.695 lb ai/acre) 35.70

12.30 21.90

9.83 18.50

8.30

TTR in Benthic Layer (Pore Water)

Corn:
MScorn_STD
ORsweetcorn_OP (1 app. X 1.30 lb ai/acre)

Ground (Incorporated) 17.60

2.37 16.80

2.31 --

Corn : NCcornW_OP
NCcornE_STD (1 app. X 2.6 lb ai/acre) 11.20

6.04 11.20

5.67 --

Sugar beet : MNsugarbeet_STD CAsugarbeetWirrg _OP (1 app. X 1.96 lb ai/acre) 4.91

4.25 4.89

4.23 --

Sorghum : TX sorghum_OP KS sorghum_STD (1app. X 1.695 lb ai/acre) 12.50

5.88 11.40

5.86 --

1 Terbufos plus its major degradates, terbufos sulfo ne and terbufos sulfo xide

. 2 EECs do not account for required vegetative buffers and setback distances.

3 SWCC modeled values are the highest and lowest TTR EECs for each crop and application rate

.

### 26 5.2 RQ V alues

A cute and chronic LOCs for fish and invertebrates are exceeded for use of terbufos on corn, sorghum, and sugar beet ( Table 6 ). A range of RQs was presented for each use representing the use scenario resulting in the lowest and highest EECs. Acute RQs for fish range from 3

- 46 and chronic RQs for fish range from 2 6

- 187. Acute RQs for aquatic invertebrates range from 11

- 210

and chr onic RQs for aquatic invertebrates range from 56

- 730. The listed species LOC (1) is not exceeded for aquatic plants (vascular or non

- vascular).

Table 6

. Aquatic RQs for Use of Terbufos 1,2,3 ,4

, 5

Taxonomic Group Crop (application rate)

Corn (1.3 lb ai/A) NC Corn (2.6 lb ai/A) Sugar Beet (1.96 lb ai/A) Sorghum (1.695 lb ai/A)

Freshwater

Animals Fish (acute) 7

- 30 20

- 32 13

- 18 16

- 46

Fish (chronic) 36

- 155 91

- 187 63

- 69 83

- 185

Invertebrate (acute) 33

- 138 91

- 146 58

- 84 72

- 210

Invertebrate (chronic) 165

- 567 377

- 713 268

- 276 328

- 730

Benthic Invertebrate (acute) 14

- 104 36

- 66 25

- 29 35

- 74

Benthic Invertebrate (chronic) 77

- 560 189

- 373 141

- 163 195

- 380

Marine/

Estuarine

Animals Fish (acute) 3

- 15 10

- 16 6

- 9 8

- 22

Fish (chronic) 26

- 111 65

- 134 45

- 49 59

- 132

Invertebrate (acute) 25

- 10 6 70

- 113 45

- 65 56

- 162

Invertebrate (chronic) 121

- 415 276

- 522 196

- 202 240

- 534

Benthic Invertebrate (acute) 11

- 80 27

- 51 19

- 22 27

- 57

Benthic Invertebrate (chronic) 56

- 410 138

- 273 104

- 119 143

- 278

Algae (listed species) 6 0.01

- 0.06 0.04

- 0.10 0.02

- 0.04 0.0 3

- 0.0 9
Aquatic Vascular plants (listed species) 6 0.02

- 0.08 0.06

- 0.10 0.0 4

- 0.05 0.04

- 0. 13

1 EECs do not account for required vegetative buffers and setback distances.

2 Range is based on use scenarios resulting in the lowest and highest EECs for each crop as provided in Table 5

. For example, the acute fish RQ range for corn (1.3 lb ai/A) is based on the peak EEC from the ORsweetcorn_OP scenario (5.52 μg/L) and MScorn_STD (23.40 μg/L).

3 Acute RQs were calculated using the peak EEC, chronic fish RQs were calculated using the 60

- day EEC, and chronic invertebrate RQs were calculated using the 21

- day EEC. Benthic invertebrate EECs were calculated using porewater EECs.

4 RQs were calculated using toxicity endpoints presented in Table 4 . The listed species RQ for aquatic plants is based on the NOAEC value. Waterflea and Mysid shrimp data were used to calculate RQs for benthic invertebrates

because those were the most sensitiv e invertebrate species and the available data for benthic invertebrates were based on water column concentrations (not spiked sediment).

5 RQs greater than 1 are rounded to the nearest whole number.

6 RQs were not calculated for non

- listed species because RQs for listed species do not exceed the LOC of 1 .0

. BOLD indicates that the RQ is greater than or equal to the LOC for aquatic animals (acute listed species LOC = 0.05 or the chronic LOC = 1.0) or aquatic plants (listed species LOC = 1.0).

### 27 5.3 Monitoring Data

The occurrence of terbufos in surface water an d groundwater w as summarized in the IRED (USEPA, 2001). For surface water, a total of 5198 samples from the United States Geological Survey (USGS) National Water Quality Assessment (NAWQA ) database were analyzed for

terbufos. Terbufos was detected in 17 surface water samples with concentrations rang ing from 0.02 to 0.56 μg/L. Terbufos groundwater monitoring information was available from several

sources including the registrant, NAWQ A, states , and EPA's Pesticides in Groundwater

Database. These data rep resent 4,563 samples from 13 states ; of these there were 20 detections of terbufos that ranged from 0.011 to 20.0 μg/L. T erbufos degradates were not included as analytes for surface water or groundwater monitoring.

A surface water and groundwater monitoring study (MRID 46873301) was conducted for terbufos, terbufos sulfo ne
, and terbufos sulfo xide by the registrant

. The study was required by the terbufos IRED (USPEA, 2001) to confirm concentrations of terbufos

, terbufos sulfo ne
, and

terbufos sulfo x ide in drinking water sources. The Agency review of this study (USEPA, 2008b)

is summarized as follows

. For the surface water, a total of 502 samples were collected from 33

sites between 1999 and 2005. For the groundwater, 73 samples were collected from 2003 to

2005. From 1999 to 2003, samples from numerous watersheds were provided by the NAWQA program. In surface water, terbufos and terbufos oxon were not detected above the reporting limits in any samples. Terbufos sulfoxide was detected in four samp les at 0.092 to 0.205 μg/L, with an additional nine estimated detections of 0.045 to 0.262 μg/L. Terbufos sulfone was detected in six samples at 0.046 to 0.114 μg/L, with 30 additional estimated detections of 0.012 to 0.034 μg/L. There were no detections of terbufos or any degradates in any of the groundwater samples.

USGS

- NAWQA m onitoring data from 2006 to the present were accessed on March 18, 2014 to

evaluate the post

- IRED trend of terbufos, terbufos sulfone, and terbufos sulfoxide concentrations

in s urface water and groundwater. This dataset included filtered surface water and groundwater monitoring data that were not available in a previously reviewed 2008 monitoring study of terbufos and its degradates in drinking water (USEPA, 2008 b ). For surface water, a total of 6740 water samples were analyzed for terbufos. Terbufos was detected in only one sample and the concentration was 0.02 μg/L. There were two detections of 0.07 μg/L and 0.17 μg/L terbufos

sulfone out of 6198 surface water samples. For groundwater, a total of 3582 water samples were analyzed for terbufos. Terbufos was detected in one sample with a concentration of 0.01 μg/L. There were no detections of terbufos sulfone in any of the groundwater samples.

Post

- IRED detecti ons and concentrations of terbufos in surface water and groundwater samples are lower than the pre

- IRED monitoring data. The Agency implemented several mitigation and risk management measures necessary to address human health and environmental risks

assoc iated with the uses of terbufos during the IRED process. In particular, the application rate for sorghum was reduced from 1.96 lb a i/A to 1.696 lb ai /A and a vegetative buffer was required

between the treated area and surface water bod ies to mitigate terb ufos exposure in surface water

. The r educe d rate for sorghum and the implementation of vegetative buffer s may have resulted in

fewer detections and lower concentrations of terbufos and its degradates in surface water and groundwater.

### 28 The NAWQA p rogram rec ently began monitoring the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States ( Carter et al., 2010 ). The re were 295 anthropogenic organic compounds (AOCs) including terbufos and terbufos sulfone monitored during 2002

– 2010 for the Source Water

Quality Assessment (SWQA ) studies. The SWQA studies are intended to complement drinking

water monitoring required by Federa l, State, and local programs, which focus primarily on post

treatment compliance monitoring. A total of 221 surface water samples were analyzed for

terbufos and terbufos sulfone. There were no detections of terbufos or terbufos sulfone in any samples.

Monitoring data for surface water, groundwater, and sediment from the California Department of Pesticide Regulation (CDPR) were searched on March 18, 2014. Terbufos was detected in only one sample and the concentration was 0.04 μg/L out of 2538 surface wat er samples. There were no detections of terbufos or its degradates in any of the groundwater samples.

T here are some limitations with the non

- targeted monitoring data cited above. Critical

information is not available to determine how well sampling events at the monitoring sites correspond with terbufos applications. The sampling frequency may be sufficient for estimating long

- term average concentrations for chronic toxicity endpoints but is inadequate for estimating peak exposures for acute endpoints. Th e monitoring results can provide a lower bound of anticipated exposures from terbufos residues in water bodies in terbufos use areas.

V I. Terrestrial LOC Assessment

6.1 Birds and Mammals

Dietary Ingestion (granules)

T

- REX ( Terrestrial Residue Exposure Model, v 1.5.2) 5 

### was used to estimate avian and mammal dietary exposure to terbufos granules based on the LD 50 

### /ft 2 

### method. Risk was assessed based on toxicity to the TGAI and to formulations when data indicated greater toxicit y. R epresentative model input and output are shown in Appendix G

.

The acute and chronic LOC s are exceeded for use of terbufos on corn, sorghum, and sugar beet ( Table 7 and 8 ). T he acute listed and non

- listed species LOCs are exceeded for 20g and 100g

bi rds (all uses). RQs are at or exceed the listed species acute LOC (0.1) for birds in the 1000g size class (all uses). RQ s exceed the non

- listed species acute LOC (0.5) for birds in the 1000g size class for uses with the 15G granule (all NC corn uses and banded uses on corn, sorghum, and sugar beet). All uses exceed the listed and non

- listed species acute LOC s for all considered size classes of mammals (15

- 1000g) . The chronic LOC (1) is exceeded for all uses (birds and mammals). Available acute dose

- based toxicity data for some granule formulations indicates greater toxicity than the TGAI; thus

, RQs are greater when based on granule toxicity. Banded application methods result in higher RQs than in

- furrow or knifed

- in application methods.

5 http: //www.epa.gov/oppefed1/models/terrestrial

### 29 T able 7 . Avian RQs for Use of Terbufos 1

, 2

Use Application

Method (timing) lb ai/

1000

ft row Product Band

width (in) Toxicity 3 RQ (acute dose) 4 RQ (chronic) 5 0.02 kg

bird 0.1 kg

bird 1 kg

bird

Corn Banded (at planting) 0.15 15G (NC) 7 TGAI 42 7 0.47 63

15G 127 20 1 N/A

0.075 CR TGAI 21 3 0.23 31

CR 30 5 0.32 N/A

15G TGAI 2 1 3 0.23 31

15G 63 10 0.69 N/A

20G 5 TGAI 30 5 0.33 4 4

4 37 6 0.41 5 5

In furrow (at planting) 0.15 15G (NC) 1 TGAI 20 3 0.22 116

15G 59 9 0.66 N/A

0.075 CR TGAI 10 2 0.11 58

CR 14 2 0. 15 N/A

15G TGAI 10 2 0.11 58

15G 30 5 0.33 N/A

20G TGAI 10 2 0.11 58

Banded (postemergence

and at cultivation) 0.075 CR 7 TGAI 21 3 0.23 124

CR 30 5 0.32 N/A

15G TGAI 21 3 0.23 124

15G 63 10 0.69 N/A

20G TGAI 21 3 0.23 124 Sorghum Knifed in (at bedding and at planting) 0.065 CR 1 TGAI 9 1 0.09 13

CR 12 2 0. 13 N/A

0.066 15G TGAI 9 1 0.10 13

15G 26 4 0.30 N/A

0.065 20G TGAI 9 1 0.09 13

Banded (at planting) 0.065 CR 7 TGAI 18 3 0.20 27

CR 25 4 0.28 N/A

0.066 15G TGAI 18 3 0.20 27

15G 55 9 0.60 N/A

0.065 20G TGAI 18 3 0.20 27

0.066 15G 5 TGAI 26 4 0.29 38

15G 77 12 0.87 N/A

0.065 20G TGAI 25 4 0.28 38 Sugar

beet Modified in

furrow and

knifed in (at planting) 0.075 CR 1 TGAI 10 2 0.11 15

CR 14 2 0.15 N/A

15G TGAI 10 2 0.11 15

15G 30 5 0.33 N/A

20G TGAI 10 2 0.11 15

Banded (at planting and postemergence) CR 7 TGAI 21 3 0.24 32

CR 30 5 0.34 N/A

15G TGAI 21 3 0.24 32

15G 64 10 0.72 N/A

20G TGAI 21 3 0.24 32

CR 5 TGAI 30 5 0.33 175

CR 42 7 0.46 N/A

15G TGAI 30 5 0.33 175

15G 89 14 0.99 N/A

20G TGAI 30 5 0.33 175

### 30 1 Product application methods (timing, lb ai/ 1000 ft row , band width) were obtained from the most recent product

labels.

2 RQs greater than 1 (acute) or 2 (chronic) are rounded to the nearest whole number.

3 Acute t oxicity based on TGAI, Bobwhite quail LD 50 = 28.6 mg ai/kg/bw; 15G, Mallard duck LD 50 = 13.21 mg ai/kg bw; 20CR Cowbird LD 50 = 16.9 mg ai/kg bw

4 RQs are based on data from single oral dose toxicity studies. Results from dietary studies can be converted to dose

equ ivalent toxicity values; these v alues result in RQs (not shown) that are similar to those based on single oral dose toxicity studies. Example conversion for LC 50 = 143 mg ai/kg diet ( MRID 00087717 ) : mg ai/kg bw = (mg ai/kg diet * daily food intake)/kg bw. daily food intake = 0.0582 * bw^0.651 (source: SIP v 1.0 manual). bw = 0.157 kg (source: mean value from MRID 00087717 ). LD 50 = 15.8 mg ai/kg bw = ( 143 mg ai/kg diet * 0.0 17 kg/day)/ 0.157 kg bw

5 The dietary

- based chronic toxicity value (NOAEC = 5 mg ai/kg diet; MRID 0161574) was co nverted to a dose equivalent toxicity value. mg ai/kg bw = (mg ai/kg diet * daily food intake)/kg bw. daily food intake = 0.0582 * bw^0.651 (source: SIP v 1.0 manual). bw = 1.136 kg (source: mean value from MRID 0161574). NOAEL = 0.278 mg ai/kg bw = (5 mg ai/kg diet * 0. 0 632 kg/day)/1.136 kg bw

BOLD indicates that the RQ is greater than or equal to the acute listed species LOC (0.1) or the chronic LOC (1.0). N/A indicates that chronic toxicity data were not available for the formulation. TGAI = technical grade active ingredient. CR, 15G, and 20G refer to Counter (terbufos) formulations. 15G (NC) = North Carolina special local

needs label for 15G.



### Table 8 . Mammalian RQs for Use of Terbufos 1

, 2

Use Application

Method (timing) lb ai/

1000

ft row Product Band

width (in) Toxicity 3 RQ (acute dose) RQ (chronic) 0.015 kg 4 0.035 kg 4 1 kg 4

Corn Banded (at planting) 0.15 15G (NC) 7 TGAI 422 22 4 18 24 9

0.075 CR, 15G 211 11 2 9 124

20G 5 TGAI 29 6 15 7 1 3 174

20G 440 233 1 9 N/A

4 TGAI 370 19 6 1 6 21 8

20G 55 1 29 2 2 4 N/A

In furrow (at planting) 0.15 15G (NC) 1 TGAI 197 104 8 116

0.075 CR, 15G 99 52 4 58

20G 99 52 4 58

20G 14 7 7 8 6 N/A

Banded (postemergence

and at cultivation) 0.075 CR, 15G 7 TGAI 211 11 2 9 124

20G 211 11 2 9 124

20G 31 5 16 7 1 4 N/A

Sorghum Knifed in (at bedding and at planting) 0.065 CR 1 TGAI 8 5 45 4 50

0.066 15G 8 6 45 4 50

0.065 20G 8 5 45 4 50

20G 12 7 67 5 N/A

Banded (at planting) 0.065 CR 7 TGAI 182 96 8 107

0.066 15G 18 4 97 8 108

0.065 20G 182 96 8 107

20G 271 14 4 12 N/A

0.066 15G 5 TGAI 257 136 11 151

0.065 20G 25 5 135 11 150

20G 3 80 201 16 N/A

### 31 Use Application

Method (timing) lb ai/

1000

ft row Product Band

width (in) Toxicity 3 RQ (acute dose) RQ (chronic) 0.015 kg 4 0.035 kg 4 1 kg 4

Sugar

beet Modified in

furrow and

knifed in (at planting) 0.075 CR, 15G 1 TGAI 99 52 4 58

20G 99 52 4 58

20G 14 8 78 6 N/A

Banded (at planting and postemergence) CR, 15G 7 TGAI 212 11 3 9 125

20G 212 11 3 9 125

20G 316 16 8 1 4 N/A
CR, 15G 5 TGAI 297 157 1 3 175

20G 297 157 1 3 175

20G 443 23 5 19 N/A

1 Product application methods (timing, lb ai/ 1000 ft row , band width) were obtained from the most recent product

labels.

2 RQs greater than 1 (acute) or 2 (chronic) are rounded to the nearest whole number.

3 Acute t oxicity based on TGAI, Rat LD 50 = 1.25 mg ai/kg/bw; 20G, rat LD 50 = 0.836 mg ai/kg bw

. Chronic dose based toxicity based on TGAI, NOAEL = 0.07 mg ai/kg bw.

4 Mammal body weight

BOLD indicates that the RQ is greater than or equal to the acute listed species LOC (0.1) or t he chronic LOC (1.0). N/A indicates that chronic toxicity data were not available for the formulation. TGAI = technical grade active ingredient. CR, 15G, and 20G refer to Counter (terbufos) formulations. 15G (NC) = North Carolina special local

needs label for 15G.



### Dietary Ingestion (contaminated fish)

KABAM (K OW 

### (based) Aquatic BioAccumulation Model, v 1.0) 6 

### was used to estimate potential bioaccumulation of terbufos in freshwater aquatic food webs and risk to piscivorus mammals and

birds that consume terbufos contaminated fish. The model bases bioaccumulation in the food

web on the octanol

- water coeff icient (Kow) of the chemical and the estimated surface water and pore water concentrations of the chemical. Although terbufos, terbufos sulfoxide, and terbufos sulfone show similar toxicity, risk was assessed based on exposure to terbufos alone because th e bioaccumulation potential of terbufos is much greater than that of terbufos sulfoxide and terbufos sulfone (terbufos log Kow = 4.71, terbufos sulfone log Kow = 2.48 ( EPISUITE estimate), and terbufos sulfoxide log Kow = 2.21 ( EPISUITE estimate ) ) . Bioaccu mulation based on TTR EECs and the bioaccumulation potential of terbufos would overestimate bioaccumulation in the food

web. The bioaccumulation potential is assumed to be low for terbufos sulfone and terbufos

sulfoxide based on their Kow values

.

The a ssessment is based on the assumption that terbufos is not metabolized by aquatic organisms (input parameter km = 0 d

- 1 

### ). The elimination rate constant value (k T 

### = 0.31 d

- 1 

### ) estimated from the laboratory BCF study is similar to the sum of the KABAM estimated loss rate constants ( i.e.

, k 2 

### + k G 

### = 0.36 d

- 1 

### ) based on fish weight and water temperature from the BCF study

. 7 

### The results

6 http://www.epa.gov/oppefed1/models/water

7 The estimated loss rate constants (k 2 and k g ) were generated using the KABAM model. All default parameters were used, with two exceptions: (1) the large fish was parame terized to represent the average body weight of the fish in the BCF study (6.4 g) and (2) the average temperature of the study (22 ° C) was entered as the model water
temperature.

### 32 of this comparison indicate that metabolism is not a substantial mechanism of depuration and supports the assumption that km = 0 d

- 1



### .

RQs were calculated for the crop scenario resulting in the lowest and highest EECs (21 day averaging period) for each use of terbufos ( Appendix F; Table F

- 4 ) ; as discussed above, EECs are based on terbufos only . Representative KABAM model results are presented in Appendix

H

.

Results from KABAM indicate a risk concern for piscivorus birds and mammals for use of terbufos ( Table 9 ). For mammals, all uses, crop scenarios, mammal size classes, and functional feeding groups exceed the LOC on an acute and chronic basis

. For birds, the chronic LOC is exceeded only for the crop scenario resulting in the highest EEC estimates for corn and sorghum

. Acute RQs for birds exceed the listed species acute LOC but not the non

- listed species LOC and only f or smaller birds in two feeding groups (represented by sandpipers and rails) for the crop scenario resulting in the highest EECs for each use of terbufos.

Table 9 . Piscivorous Wildlife RQs for Use of Terbufos 1,2

Crop (application rate) Wildlife Species A cute RQ Chronic RQ

Dose Based Dietary Based Dose Based Dietary Based

Corn (1.3 lb ai/A) Mammalian fog/water shrew 0.06

- 1 N/A 2

- 31 0.28

- 6

rice rat/star

- nosed mole 0.08

- 2 N/A 2

- 38 0.28

- 6

small mink 0.11

- 2 N/A 3

- 52 0.42

- 8 large mink 0.12

- 2 N/A 3

- 57 0.42

- 8

small river otter 0.13

- 2 N/A 3

- 61 0.42

- 8 large river otter 0.15

- 3 N/A 4

- 73 0.47

- 9

Avian sandpipers 0.01

- 0.28 <0.01

- 0.04 N/A <0.1

- 1.1

cranes <0.01

- 0.02 <0.01

- 0.04 N/A <0.1

- 1.2

rails <0.01

- 0.15 <0.01

- 0.05 N/A <0.1

- 1.3

herons < 0.01

- 0.03 <0.01

- 0.05 N/A <0.1

- 1.4 small osprey <0.01

- 0.04 <0.01

- 0.06 N/A <0.1

- 1.6 white pelican <0.01

- 0.02 <0.01

- 0.06 N/A <0.1

- 1.8

NC Corn (2.6 lb ai/A) Mammalian fog/water shrew 0.51

- 0.52 N/A 13 2

rice rat/star

- nosed mole 0.62

- 0.65 N/A 16 2

small mink 0.86

- 0.89 N/A 21

- 22 3

- 4 large mink 0.95

- 0.98 N/A 24

- 25 3

- 4

small river otter 1 N/A 25

- 26 3

- 4 large river otter 1 N/A 32

- 34 4

Avian sandpipers 0.12 0.02 N/A 0.46

- 0.48

cranes <0.01 0.02 N/A 0.48

- 0.50

rails 0.06 0.02 N/A 0.54

- 0.56

herons 0.01 0.02 N/A 0.57

- 0.59 small osprey 0.02 0.02 N/A 0.69

- 0.71 white pelican <0.01 0.03 N/A 0.79

- 0.84

### 33 Crop (application rate) Wildlife Species A cute RQ Chronic RQ

Dose Based Dietary Based Dose Based Dietary Based

Sugar beet (1.96 lb ai/A) Mammalian fog/water shrew 0.25

- 0.28 N/A 6

- 7 1.1

- 1.2

rice rat/star

- nosed mole 0.31

- 0.34 N/A 8

- 9 1.1

- 1.3

small mink 0.42

- 0.47 N/A 11

- 12 1.7

- 1.9 large mink 0.47

- 0.52 N/A 12

- 13 1.7

- 1.9

small river otter 0.50

- 0.56 N/A 13

- 14 1.7

- 1.9 large river otter 0.65

- 0.69 N/A 16

- 17 2

Avian sandpipers 0.06 <0.01 N/A 0.23

- 0.25

cranes <0.01 <0.01 N/A 0.24

- 0.26

rails 0.03 ≤0.01 N/A 0.27

- 0.30

herons <0.01 0.01 N/A 0.28

- 0.31 small osprey ≤0.01 0.01 N/A 0.34

- 0.37 white pelican <0.01 0.01 N/A 0.40

- 0.43 Sorghum (1.695 lb ai/A) Mammalian fog/water shrew 0.35

- 0.96 N/A 9

- 24 1.5

- 4

rice rat/star

- nosed mole 0.43

- 1 N/A 11

- 29 1.6

- 4

small mink 0.59

- 2 N/A 15

- 40 2

- 6 large mink 0.66

- 2 N/A 16

- 44 2

- 6

small river otter 0.71

- 2 N/A 18

- 47 2

- 6 large river otter 0.86

- 2 N/A 21

- 55 3

- 7

Avian sandpipers 0.08

- 0.22 0.01

- 0.03 N/A 0.32

- 0.86

cranes ≤0.01 0.01

- 0.03 N/A 0.34

- 0.90

rails 0.04

- 0.12 0.01

- 0.04 N/A 0.37

- 1.0

herons <0.01

- 0.02 0.01

- 0.04 N/A 0.40

- 1.1 small osprey 0.01

- 0.03 0.02

- 0.05 N/A 0.48

- 1.3 white pelican ≤0.01 0.02

- 0.05 N/A 0.53

- 1.4

1 Range is based on use scenarios resulting in the lowest and highest terbufos EECs for each crop as provided in Appendix F, Table F

- 4 . For example, the RQ range for corn is based on the 21 day EEC s (terbufos only) from the ORsweetcorn_OP scenario (0.13 μg/L surface water; 0.34 μg/L pore water) and MScorn_STD (2.44 μg/L surface water; 8.74 μg/L pore water).

2 RQs greater than 1 (acute) or 2 (chronic) are rounded to the nearest whole number.

BOLD indicates that the R Q is greater than or equal to the acute listed species LOC (0.1) or the chronic LOC (1.0).



### Inhalation

The Screening Tool for Inhalation Risk (STIR v1.0) 8 

### was used to provide an upper bound

estimate of bird and mammal exposure to terbufos through vapor inhalation

. There is no spray drift exposure (droplet inhalation) because terbufos is applied as a granule. The screening suggests that terbufos use has the potential for significant vapor inhalation risk (the ratio of vapor

concentration in the air to t he inhalation LD 50 

### exceeds the screening threshold of 0.1)

. Model inputs and output are presented in Appendix I

.

8 http://www.epa.gov/oppefed1/models/terrestrial

### 34 Drinking Water

The Screening Imbibit ion Program (SIP v.1.0 ) 8 

### was used to calculate an upper bound estimate of bird and mammal exposure t o terbufos in drinking water. The screening i ndicates potential acute and chronic risk to birds and mammals through the consumption of terbufos

- contaminated drinking water

. Model results are presented in Appendix J

.

6.2 Terrestrial and Semi

- Aquatic Pla nts

TerrPlant (v 1.2.2) 8 

### was used to calculate EECs for characterizing exposure to terrestrial and

semi

- aquatic plants through run

- off of terbufos

. There is no spray drift exposure because terbufos is applied as a granule. The listed species LOC of 1 is not exceeded for any use. Input and output for the maximum application rate (NC use on corn) are shown in Appendix K

.

V I I

. Risk Characterization

7.1 Aquatic Organisms

Aquatic Fish and Invertebrates

The standard modeling approach based on exposure to total toxic residues (terbufos, terbufos sulfoxide, and terbufos sulfone) indicates an acute and chronic risk concern for fish and aquatic invertebrates from use of terbufos on corn, sorghum, and sugar beet ( Table 6 ). TTR was used

to calculate EECs because terbufos sulfoxide

, and terbufos sulfone are more persistent than terbufos and available toxicity data indicate that they are similar in toxicity to terbufos. Concerns about adverse effects to aquatic organisms from terbufos use are strongly suppo rted by widespread fish kill incidents. Aquatic i ncidents prior to the RED do not necessarily reflect any of the mitigation which now requires implementation of vegetative buffers and setbacks

between the treated field and water bodies

. Buffers may make aquatic incidents less likely to

occur and i t is noted that the number of reported fish incidents per year has declined since the RED; however, this does not necessarily indicate a lack of incidents or reduced risk. Reliance on the frequency of incidents may significantly underestimate the extent of the actual impacts. Adverse ecological effects cannot be assumed to be reliably detected and reported. Before an incident can be reported, it must be observed and attributed to terbufos. Reproductive effects o r other sublethal effects, effects on eggs or small age classes, or impacts on relatively small species (invertebrates, amphibians, or small fish species) are likely to escape immediate

detection. For example, t he only invertebrate species cited in terbuf os related incidents is crayfish, which is a relatively conspicuous invertebrate. Toxicity data indicate that invertebrates are more sensitive to terbufos than fish; thus, effects on invertebrates can be assumed when fish kill incidents are reported but t he absence of fish incidents does not indicate an absence of

adverse effects on invertebrates.

In many cases, incident reports for fish kills associated with terbufos use on corn indicate that

residues of terbufos, terbufos sulfone, or terbufos sulfoxide were detected at levels in the surface

water of static systems that are similar to those predicted by modeling of static water systems ( Appendix E , Table E

- 1 and Appendix F, Table F

- 4 ). Surface water concentrations observed

### 35 in the incident reports reflect a wide range of variables including but not limited to application rate and method, time elapsed between application and water sampling, distance of the water body from the application site, and the size of the water body relative to that of the treated f ield. Monitoring data generally show lower concentrations of terbufos in flowing water systems than predicted through modeling for static water system s
, but non

- targeted sampling is unlikely to capture peak concentrations ( see Section V ). Nonetheless, monitoring information indicates that concentrations of terbufos, terbufos sulfone, and terbufos sulfoxide sometimes reach levels in flowing water systems that would adversely affect aquatic animals. For instance, more recent

NA WQ A monito ring data show surface water concentrations of terbufos up to 0.02 μg/L and terbufos sulfone concentrations up to 0.17 μg/L

, which are high enough to trigger an acute risk concern for aquatic invertebrates.

Several open literature studies showed greater a cute (freshwater invertebrates) and chronic (freshwater fish) toxicity than demonstrated in registrant submitted studies (discussed in Section

IV ). RQs were not calculated because the studies were classified as qualitative. These data do not change the r isk conclusions; however, it does suggest that acute risk to freshwater invertebrates and chronic risk to freshwater fish may be greater than indicated by toxicity based on registrant submitted data.

In addition, one open literature study showed adverse developmental effects on southern bell frogs exposed to 10 μg terbufos sulfone/L for 10 weeks. Assuming that terbufos and terbufos sulfoxide are similar in toxicity to terbufos sulfone as for other taxa, then adverse effects may be reasonably expected to occur given that 60

- day TTR surface water EECs range from 3.63 to
18. 70 μg/L.

The quantitative risk assessment (i.e., calculation of RQs) is based on upper bound EECs that do not consider the labeled setbacks and vegetative buffers. It is assumed that b uffers will reduce loading to aquatic systems due to run

- off from treated fields; thus, risk to aquatic organisms may be reduced with use of buffers. Although c urrently available models cannot account for the impact of vegetative buffers ( see Section V fo r discussion) , t he potential impact of buffers is characterized by calculating how effective they would need to be to reduce EECs and thus RQs

below LOC s

. While there is good evidence that buffers can reduce pesticide movement into

water bodies to some ex tent, there is still a great deal of uncertainty regarding the performance of buffers, which includes but is not limited to proper design and placement and the duration of their efficacy. Based on a review of available research, EFED hypothesized that the use of vegetative buffers may reduce loading of total toxic residues of terbufos in aquatic systems by 50% to 90% ( see USEPA, 2015 for a full discussion). In comparison, l oading would need to be

reduced more than about 93% to 99.9% for RQs to be below LOCs

, depending on the crop, taxonomic group (fish or invertebrate; freshwater or marine / estuarine species ), listed or non

listed species status, and LOC (acute or chronic). There is only one exception that requires loading reductions less than the hypothesized maximum of 90%. A vegetative buffer would

need to reduce the “no buffer” EECs by ≥ 85% for the scenario with the lowest surface water EECs (5.52 μg/L; corn; ORsweetcorn_OP scenario) to be below the acute non

- listed species

LOC for marine/estuarine fish ( Figure 1 ). For all other scenarios, loading would need to be reduced more than 90% for the RQ to be below the acute non

- listed species LOC for

marine/estuarine fish. Overall, available information suggests that loading may be r educed up to

### 36 90% with the use of vegetative buffers; however , the overall risk concerns for fish and aquatic invertebrates remain because RQs remain above the LOCs after accounting for those reductions

.

Figure 1.

Aquatic plants

The LOC (1.0) is not exceeded for listed aquatic plants (RQs ≤ 0.13) from any labeled use. Although EC 50 

### s were not established in the available studies, there is not a risk concern for non

listed plants given that there is not a risk concern for l isted plants. Although there is open literature data for a freshwater diatom ( Nitzschia sp.) that showed a more sensitive EC 50 

### value than registrant submitted data, the reported EC 50 

### value is higher than the NOAEC values in the registrant submitted data w hich did not trigger a risk concern for listed species. Although the NOAEC was not reported

, there is little uncertainty in the risk conclusions of this assessment because there are not currently any listed algal species. That same study also tested two o ther algal species that showed less sensitivity to terbufos. Based on the weight of the available

evidence

, there is not a risk concern for aquatic vascular or non

- vascular plants.

7.2 Terrestrial Organisms

Birds and Mammals

There are several potential sources of terbufos exposure to birds and mammals. Granules may be ingested directly by birds foraging for seed and grit at or below the soil surface on treated areas.

T he similarity of the granule s to natural forage or grit has been suggested as an important characteristic which may influence ingestion of granules. Grit preferences are expected to vary

### 37 among avian species and may depend on variables including size, shape, texture, and color.

Birds and mammals may also ingest granules adhered to the surface of invertebrate prey items such as earthworms and grubs or accidentally ingest granules when foraging for seeds and insects. Piscivorous birds and mammals may be exposed to terbufos residues in c ontaminated fish. Other routes of exposure for both birds and mammals include ingestion of contaminated drinking water, vapor inhalation, and dermal exposure through contact with treated soil. The weight of evidence from the assessment of various pathway s supports an acute and chronic risk

concern for birds and mammals from labeled uses of terbufos.

The standard modeling scenario for consumption of granules ( LD 50 

### /ft 2 

### method) indicates an

acute and chronic risk concern for evaluated size classes of birds a nd mammals for use on corn, sorghum, and sugar beet ( Table 7 and 8 ). While the LD 50 

### /ft 2 

### method has no ecological meaning, it is used as a means to characterize the level of exposure in a relatively small foraging area; therefore, the likelihood of risk. Available acute dose

- based toxicity data for granules indicates greater toxicity than TGAI; thus

, RQs are greater when based on granule toxicity.

Banded application methods result in higher RQs than in

- furrow or knifed

- in application methods. Soil incorporation using conventional commercial equipment greatly reduces the number of exposed granules, but does not eliminate potential exposure. The ris k assessment assumes that 15% of granules are exposed and available for banded applications and 1% are exposed for in

- furrow and knifed

- in applications. However, varying numbers of exposed granules may result from each type of use specified on terbufos la bels.

Exposure values were estimated for along treated rows where some type of incorporation is concurrent with application. The number of granules that may be found in turn areas at row ends where application equipment is raised from the soil may be c onsiderably higher than along rows. Label directions specify incorporating product that is visible on the soil surface in turn areas; however, it may not be practical to do this immediately after granules are deposited and the level of incorporation may n ot be equal to that along the rows. Therefore, risk at row ends may be greater than suggested by risk along treated rows.

The likelihood of consuming enough terbufos to cause adverse effects is related in part to the number of granules containing that dos e and the number of granules readily available for foraging. The fewer the number of granules and the higher the availability, the greater the risk concern. In general, very few granules are required to reach either the acute listed or non

- listed species LOCs ( Appendix L ). The number of exposed granules is relatively high in compa rison. For birds, the listed species acute LOC is exceeded consuming <1 to 125 granules

, depending on the bird weight and terbufos product (CR, 15G, or 20G)

. 9 

### For mammals, the listed species acute LOC is exceeded consuming <1 to 10 granules

, depending on the mammal weight and terbufos product. Exceedance of the non

- listed species acute LOC requires consuming 5 times as many granules. For a given use, the formulation also impa cts the likelihood of consuming enough granules t o exceed the acute LOCs ; a fewer number of CR granules are required than 20G or 15G granules due primarily to their larger size. 10

9 Range is based on formulat ion toxicity when available instead of TGAI toxicity.

10 Difference in formulation toxicity is also a factor. Although there is not a complete formulation toxicity dataset for either birds or mammals, available information suggests that differences in gra nule size may be the primary factor differentiating the formulations in terms of the number of consumed granules that result in a risk concern.

### 38 Results from KABAM indicate a risk concern for piscivorus birds and mammals for all uses of

terbufos. The results suggest that mammals are more at risk than birds. This assessment is based on the assumption that terbufos is not metabolized by aquatic organisms in the food chain

. The assumption is supported by results from the BCF study in conjunction with KABAM estimates

of loss rate constants which indicate that metabolism is not a substantial mechanism of depuration for fish ( see Section 6.1 ); nonetheless, risk may be overestimated to the extent that

terbufos is metabolized i n different compartments of the aquatic food chain. Although e xposure concentrations in water may be high enough to cause mortality in sensitive individuals and species of fish and invertebrates , the potential for bioaccumulation in the food chain may occ ur in less sensitive individuals and species. In addition, the assessment was based on EECs that do not consider the labeled setbacks and vegetative buffers. Currently available models cannot account for the impact of these buffers ( see Section V for dis cussion). The potential impact of the buffers was characterized by calculating how effective they would need to be to reduce EECs

below the level of concern. Buffers need to be very effective at reducing runoff to eliminate the risk concern; however, in some cases the buffers may be effective enough

. As discussed above, it is hypothesized that buffers may reduce loading between 50% and 90%. RQs would be below

the acute and chronic LOCs for the scenario with the lowest bioaccumulation potential (ORsweetc orn_OP scenario) if loading is reduced by 75% compared to the “no buffer” EECs

. In

contrast, the scenario with the highest bioaccumulation potential (MScorn_STD ) would require a 95% reduction in loading compared to the “no buffer” EECs to eliminate the ri sk concern for birds (acute and chronic) and for mammals on an chronic dietary basis while RQs would remain

above the acute and chronic LOC on a dose basis for mammals even with a 95% reduction in loading

.

The STIR model indicates a potential risk to birds and mammals from vapor inhalation. This is not unexpected given that terbufos is highly toxic (acute inhalation) and semi

- volatile

. The screen assumes a maximum vapor concentration in air at saturation for 1 hour ; the refore, it
represents an upper

- bound exposure value and provides a conservative estimate of exposure at the screening level . The screen indicates that the ratio of vapor concentration (at saturation) to inhalation toxicity is 108 x above the screening thre shold of 0.1 for mammals and 40 x above the

threshold for birds ( based on an estimated inhalation toxicity value ) . Although avian inhalation toxicity data would be useful for better addressing potential risk, it is likely to show that terbufos is highly to xic ( as it is to mammals ) ; therefore , indicating a potential risk through vapor inhalation exposure

. The vapor pressure ( 3.16 x 10 - 4 

### mm Hg) and Hen r y’s Law Constant (2. 22 x

1 0 - 5 

### atm m 3 

### /mol) suggest that some terbufos will dissipate by diffusion into the at m o s phere; however, the amount will likely vary depending on site conditions

, appli c ation m ethods , and the rate of photodegradation in the atmosphere . For example, exposure from v olatilization m ay be greater for terb u f os that re m ains on the s o il surface after incorpo r ation (i.e., along rows and at the end of rows) than for terbufos that is incorporated into the soil. Likewise, lightly incorporated applications may result in greater exposure than applications requiring deeper incorporation. Vapor phase exposure estimates can be refined using a flux rate measured at a representative use

site coupled with a n air dispersion model ( e.g. , AERSCREEN or PERFUM ) . EFED

recommends submission of a field vol atility study to refine exposure estimates.

Given the results of the conservative screening

, exposure to terbufos through volatilization may or may not be a sole cause of adverse effects to non

- target animals; however

, the screening does

### 39 suggest that when aggregated with other routes of exposure ( i.e ., diet, drinking water, and dermal), terbufos exposure through vapor inhalation may contribute to a total exposure that has potential for effects to non

- target animals.

The SIP model indicates a potential risk to birds and mammals from acute and chronic exposure to terbufos contaminated drinking water. This screening is qualitative, is based on drinking water exposure alone, and is based on several conservative assumption s which add considerable

uncertain ty to this risk conclusion ( see Appendix J )

. Nonetheless, when aggregated with other

routes of exposure ( i.e ., diet, inhalation, and dermal), terbufos exposure through drinking water may contribute to a total exposure that has potential for effects to non

- target animals.

The open literature data for acute toxicity to birds (discussed in S ection IV ) were not used quantitatively in the risk assessment. The data would not change general conclusions about acute risk to birds; however, it does suggest that acute risk may be greater than that indicated by acute toxicity of the TGAI to bobwhite quail (MRID 00106551).

Overall, the weight of available evidence supports an acute and chronic risk concern for birds

and mammals from the labeled use of terbufos. The risk concern based on the LD 50 

### /ft 2



### assessment is supported by field studies. In addition, bird and mammal incidents are reported in

the three incident databases (EIIS, Aggregate Incident Data System , and AIMS), although it is

noted that some reported in EIIS may be misuse or misapplications of terbufos . Screening level drinking water and vapor phase exposure estimates suggest a potential risk concern as well. Finally, there is a potential risk concern for piscivorus birds and mammals from consuming terbufos contaminated fish. Cumulative exposure to t erbufos from multiple pathways may be an important consideration in the risk of terbufos even if each pathway contributes a small amount to total exposure given that terbufos is highly toxic to birds and very highly toxic to mammals.

Non

- Target Terrestria l Invertebrates

Terbufos is a systemic granular pesticide , thus it is translocated into plant tissues after soil applications

. Exposure of honey bees to systemic pesti cides via soil applications is expected to result primarily from translocation to plant tissues (pollen, nectar, exudates, and honeydew) ; therefore, it is assumed that the primary route of exposure is through diet (USEPA, 2012 b )

. Exposure may occur from visiting plants on the treatment field . P lants off the treated field may also contain residues if run

- off occurs

. Bees could be exposed through direct contact with exposed granules; however, this exposure pathway is much less likely and the proposed Tier I exposure methods do not include a methodology for addressing this e xposure pathway. Dietary

r isk could not be assessed because acute and chronic oral toxicity ( adult or larval ) data are not available for terbufos or phorate, the structural analog of terbufos. Although risk cannot be quantified it is reasonable to expect risk to honeybees given that terbufos is an insecticide and that it is systemic. Submission of acute and chronic oral toxicity data (adult and larval) would be useful for refining and characterizing the degree of risk.

### 40 Terrestrial Plants

The LOC (1.0) is not exceeded for listed plants located in dry or semi

- aquatic locations (RQs ≤ 0.13) from any labeled use. There is no risk from spray drift because the products are applied as a granule. Vegetative vigor toxicity data were not available; howeve r, given the mode of action of terbufos it is assumed that the seedling emergence data are likely representative of potential effects on growth of older plants. Although an EC 25 

### was not established in the available seedling emergence study, there is no ri sk concern for non

- listed plants given that there is no risk concern for listed plants.

Some open literature data suggest that effects to plants (phytotoxicity other than growth and survival and field yield) may occur at rates lower to or equal to the 2 l b ai/A NOAEC observed in the registrant submitted data. Effects were observed at concentrations from 1

- 2 lb ai/A; however, NOAECs were not established. Chlorosis (7 day old corn) and decreased tissue Zn concentration (at harvest) were observed in corn wh ile treated plants showed growth (chlorophyll, height, and weight) that was similar to or greater than control plants later in the growing season. Two field studies showed effects on yield; however, there is inherent uncertainty as to the cause of these e ffects and the effects did not occur consistently from year to year or site to site.

Only two incidents reported for terbufos in the EIIS database involve effects on plants (corn) and both were likely caused by joint application of other herbicides. In one case the herbicide application was a misuse. In both cases flumetsulam, an ALS

- herbicide, was one of two herbicides applied along with terbufos. Terbufos and other OP insecticides increase the risk of plant injury in corn plants due to toxic effects of ALS

- herbicides . As such

, the terbufos labels provide warnings about the timing of application of terbufos and ALS

- herbicides. This

interaction occurs because terbufos and ALS

- herbicides are degraded by the same enzyme system; thus, the presence of te rbufos may reduce the rate of degradation of the herbicide and allow it to accumulate in the plant to toxic levels. 11 

### Six incidents of minor plant damage are reported in the Aggregate Incident Data System. Details of these incidents are not reported;

howe ver, it is certainly possible that they could be related to co

- exposure with herbicides given

the know n interaction of certain herbicides with terbufos.

Based on the weight of evidence there is little risk concern for direct effects to terrestrial plants from the labeled uses of terbufos with the exception of terbufos potentially increasing the toxicity of herbicides such as ALS

- inhibitors when both terbufos and the herbicide are taken up by a plant in sufficient quantities.

VI II

. Risk to Listed Spec ies

In November 2013, the EPA, along with the U.S. Fish & Wildlife Service (USFWS), the National Marine Fisheries Service (NMFS) (collectively, the Services), and the U.S. Department of Agriculture (USDA) released a summary of their joint Interim Approaches for assessing risks to listed species from pesticides. The Interim Approaches were developed jointly by the agencies in response to the National Academy of Sciences’ (NAS) recommendations and reflect

11 http://www.weeds.iastate.edu/mgmt/qtr00

- 1/opinteractions.htm

### 41 a common approach to risk assessment shared by the agencies as a way of addressing scientific

differences betw een the EPA and the Services. The NAS report outlines recommendations on specific scientific and technical issues related to the development of pesticide risk assessments

that EPA and the Serv ices must conduct in connection with their obligations under the Endangered Species Act (ESA) and the Federal Insecticide, Fungicide, and Rodenticide Act ( FIFRA )

.

The joint Interim Approaches were released prior to a stakeholder workshop held on November 15, 2013. In addition, the EPA presented the joint Interim Approaches at the December 2013 Pesticide Program Dialogue Committee (PPDC) and State

- FIFRA Issues Research and Evaluation Group (SFIREG) meetings, and held a stakeholder workshop in April 2014, allowing additional opportunities for stakeholders to comment on the Interim Approaches. As part of a phased, iterative process for developing the Interim Approaches, the agencies will also consider public comments on the Interim Approaches in connection with the development of upcoming Registration Review decisions. The details of the joint Interim Approaches are contained in the white paper “Interim Approaches for National

- Level Pesticide Endangere d Species Act Assessments Based on the Recommendations of the National Academy of Sciences April 2013 Report,” dated November 1, 2013.

Given that the agencies are continuing to develop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habitat, this preliminary risk assessment for terbufos does not contain a complete ESA analysis that includes effects determinations for specific listed species or designated critical habitat. Although EPA has not yet completed effects determinations for specific species or habitats, for this preliminary assessment EPA conducted a screening

- level

assessment for all taxa of non

- target wildlife and plants that assumes for the sa ke of the assessment that listed species and designated critical habitats may be present in the vicinity of the application of terbufos. This screening level assessment will allow EPA to focus its future evaluations on the types of species where the pote ntial for effects exists once the scientific methods being developed by the agencies have been fully vetted. This screening

- level risk assessment for terbufos indicates potential risks of direct effects to listed mammals, birds, terrestrial invertebrates, fish, and aquatic invertebrates on all of its registered use sites. Listed species of aquatic and terrestrial plants may also be affected through indirect effects because of the potential for direct effects on listed and non

- listed species upon which such species may rely. Potential direct effects on listed mammals, birds, terrestrial invertebrates, fish, and aquatic invertebrates from the use of terbufos may be associated with modification of Primary Constituent Elements (PCEs) of designated critical hab itats, where such designations have been made. Once the agencies have fully developed and implemented the scientific methods necessary to complete risk assessments for endangered and threatened (listed) species and their designated critical habitats, thes e methods will be applied to subsequent analyses for terbufos as part of completing this registration review.

I V. Endocrine Disruptor Screening Program

As required by FIFRA and the Federal Food, Drug, and Cosmetic Act ( FFDCA ) , EPA reviews

numerous studies to assess potential adverse outcomes from exposure to chemicals.

### 42 Collectively, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or syst emic toxicity. These studies include endpoints which may be susceptible to endocrine influence, including effects on endocrine target organ histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, a nd sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effects in different taxonomic groups. As part of registration

review of terbufos

, EPA reviewe d these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), terbufos is subject to the endocrine screening part of the Endocrine Disruptor S creening Program (EDSP).

EPA has developed the EDSP to determine whether 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 o ther such endocrine effects as the Administrator may designate.” The EDSP employs a two

- tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a

chemical substanc e to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP whe re EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine

- related effects 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 pesticide ac tive ingredients and 9 inert ingredients. A second list of chemicals identified for EDSP screening was published on June 14, 2013 12 

### and includes some pesticides scheduled for registration review and chemicals found in water

. Neither of these lists should be construed as a list of known or likely endocrine disruptors.

Terbufos and terbufos sulfone (degradation product) are on List 2. List 2 represents the next set

of chemicals for which EPA intends to issue test orders/data call

- ins in the near future. For further information on the status of the EDSP, the policies and procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit the website. 13

12 http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPPT

- 2009

- 0477

- 0074

13 http://www.epa.gov/endo/

### 43 X

. References

Note: Open literature toxicity study references from the ECOTOXicology database are listed in Appendix M

.

Carter, J.M., Kingsbury, J.A., Hopple, J .A., and G.C. Delzer. 2010. Concentration D ata for

A nthropogenic O rganic C ompounds in G roundwater, S urface W ater, and F inished W ater of

S elected C ommunity W ater S ystems in the United States, 2002

– 10

. U.S. Geological Survey Data

Series 544.

Felsot, A., L. Wei, and J. Wilson. 1982. Environmental C hemodynamic S tudies with T erbufos (Counter) I nsecticide in S oil under L aboratory and F ield C onditions. Journal of Environmental Science and Health. Vol. B17(6), p p. 649

- 673

.

Majewski, M.S. and P.D. C apel. 1995. Pesticides in the Atmosphere

- Distribution, Trends, and Governing Factors. Pesticides in the Hydrologic System. Ann Arbor Press, Inc, Chelsea, MI.

USEPA. 1999. Revised EFED RED Chapter. August 26, 1999. DP 257287 +



### .

USEPA. 2001. Interim Reregistration Eligib ility Decision [Terbufos] . September 2001

.

USEPA. 2006a. Standardized Soil Mobility Classification Guidance. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division. April 2 1, 2006

.

USEPA. 2006b. (P)RZM (E)XAMs Model Shell, Version 5.0. November 15, 2006. Environmental Fate and Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Preventio n. U .S. Environmental Protection Agency. http://www.epa.gov/oppefed1/models/water /

USEPA

. 2008a. White Paper on Methods for Assessing Ecological Risks of Pesticides with Persistent, Bioaccumulative and Toxic Characteristics. Office of Chemical Safety and Pollution Prevention. U. S. Environmental Protection Agency. http://www.epa.gov/scipoly/sap/meetings/2008/october/sap_pbt_whitepaper_final_Oct_7_08d.pdf



### USEPA. 2008b. Data Evaluation Record on a 167

- 1/Drinking wat er Monitoring study of

T erbufos. MRID 46873301. DP 332141

.

USEPA. 2009. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version 2.1. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substanc es, Office of Pesticide Programs, Environmental Fate

and Effects Division

. October 22, 2009. http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

### 44 USEPA. 2012a. Standard Operating Procedure for Using the NAFTA Guidance to Calculate Repres entative Half

- life Values and Characterizing Pesticide Degradation. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division. November 30, 2012. http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/NAFTA_Degradation_Kinetics.htm



### USEPA. 2012 b

. White Paper in Support of the Proposed R isk Assessment Process for Bees

, September 11

– 14, 2012

.

USEPA. 2013. Data on Terbufos and Its Environmental Transformation Products in Support of

the ROCKS. DP 416458

.

USEPA. 2014. Usage Report in Support of a Registration Review for Terbufos. February 11,

2014. DP 417801

.

USEPA. 2015. Adjusted Time

- Series Distribution of the Total Toxic Residues of Terbufos from Use on Sorghum to Account for the Theoretical Loading Reduction of Terbufos and its Degradates to Surface Water in the Presence of Label

- Prescribed Vegetative Buffers. DP

428089.

### 45 Appendix A : DT 50s 

### Submitted Environmental Fate Studies

Hydrolysis (MRID 44862501)

Temperature adjusted DT 50 

### @ 25o C is 1.5 days

. The f ollowing guidance was used in calculating temperature adjusted DT50s (USEPA, 2009)

.

### 46 Aquatic Photolysis (MRID 41181101)

Estimated DT 50 

### is 1.77 days @ 25o C

.

### 47 Aerobic Soil Metabolism (MRID 00156853)

Aerobic Soil Metabolism (MRID 41181101)

The 90 th 

### percen tile DT 50 

### is 14.7 days

.

### 48 Aerobic Aquatic Metabolism (MRID 44672204)

T he t emperature adjusted 90 th 

### percen tile DT 50 

### @ 25o C is 36.2 days

.

### 49 Anaerobic Soil Metabolism (MRID 41749801)

Terrestrial Field Dissipation (MRID 0087708)

### 50 Terrestrial Field Dissipation (MRID 0087706)

Terrestrial Field Dissipation (MRID 41883101 and 41883102)

### 51 Hydrolysis (MRID 44862501)

Temperature adjusted DT 50 

### @ 25o C is 65.1 days

.

Aerobic Soil Metabolism (MRID 00156853)

### 52 Hydrolysis (MRID 44862501)

Temperature adjusted DT 50 

### @ 25o C is 43.8 days

.

Aerobic Soil Metabolism (MRID 00156853)

### 53 Appendix B : Degradate Formation in Fate Studies

Table B

- 1. Terbufos and Its Enviro nmental Transformation Products

Common Name ( Synonym ) Chemical Name Chemical Structure Study Type MRID Maximum

%AR 1 (day) Final %AR 1 (day)

P arent

Terbufos

( AC 92100 ) S

- [[(1,1

- dimethylethyl)thio]methyl]O,O

diethylphosphorodithioate

CAS No.: 13071

- 79

- 9

Formula: C 9 H 21 O 4 P 1 S 3 MW: 288.4 g/mol

SMILES: CCOP(=S)(OCC)SCSC(C)(C)C Hydrolysis 00087694

NA 117.7

- 22.63 (28d)

44862501 7.22

- 16.6 (1.6

- 30 d)

Aqueous photolysis 00161567 3.2 (6 d)

44927918 11.3 (7 d)

Aerobic s oil 00156853 NR

Anaerobic s oil 41749801 82.7 (60 d)
Aerobic aquatic

metabolism 44862502 2 0.5

- 12 (161

- 189 d)

Terrestrial f ield

d issipation 00087708 0.02 (100 d)

Major (>10%) Transformation Products

Formaldehyde

(Degradate A) 3 Formaldehyde

Formula: CH 2 O

CAS No.: 000050

- 00

- 0

MW: 30.03 g/mol

SMILES: O=C Hydrolysis 00087694 69.9 (28 d) 69.9 (28 d)

44862501 96.1 (1.6 d) 96.1 (1.6 d)

Aqueous photolysis 00161567 71.9 (6 d) 71.9 (6 d)

44862502 2 33.8 (2 d) NR (30 d)

44862502 3 16.9 (30 d) 16.9 (30 d)

44862502 3 35.2 (30 d) 35.2 (30 d)

41181101 Detected, not quantified

Terbufos s ulfoxide

(CL 94301) S

- [[(1,1

- dimethylethyl)sulfinyl]methyl] O,O

- diethylphosphorodithioate

Formula: C 9 H 21 O 3 P 1 S 3 MW: 304.42 g/mol

SMILES:
[ CCOP(=S)(OCC)SCS(=O)C (C)(C)C Aerobic s oil 00156853 52.3 (30 d) 5.9 (365 d)

Anaerobic s oil 41749801 6.2 (15 d) 3.8 (60 d)
Aerobic aquatic 44862502 2 9.98 ( 3 d) NR (30 d)

Terrestrial f ield

d issipation 00087708 0.580 0.02 (100 d)

### 54 Common Name ( Synonym ) Chemical Name Chemical Structure Study Type MRID Maximum

%AR 1 (day) Final %AR 1 (day)

Terbufos s ulfone (CL94320) S

- [[(1,1

- dimethylethyl)sulfonyl]methyl] O,O

- diethylphosphorodithioate

Formula: C 9 H 21 O 4 P 1 S 3 MW: 320.42 g/mol

SMILES: CCOP(=O)(OCC)SCS(=O)(=O) C(C)(C)C Aerobic s oil 00156853 20.1 (60 d) 2.3 (365 d)

Anaerobic s oil 41749801 4.0 (15 d) 3.7 (60 d)

Aerobic a quatic 44862502 2 1.82 (30 d) 1.82 (30 d)

Terrestrial f ield

d issipation 00087708 0.12 (80 d) 0.02 (100 d)

Carbon dioxide Carbon dioxide

Formula: CO 2 MW: 44.1 g/mol

SMILES: O=C=O 

## O O Aerobic soil 00156853 46 (365 d) 46 (365 d)

Anaerobic s oil 41749801 3.1 (30 d) 2.0 (60 d)

Aerobic a quatic 44862502 2 61.8 (30 d) 61.8 (30 d)

Minor (<10%) Transformation Products

Terbufoxon

(CL94221) S

- [[(1,1

- dimethylethyl)thio]methyl]O,O

diethylphosphorothioate

Formula: C 9 H 21 O 3 P 1 S 2 MW: 272.36 g/mol

SMILES: C(C)(C)(C)SCSP(=O)(OCC)O

CC Anaerobic s oil 41749801 1.7 (15 d) 1.3 (60 d)

### 55 Common Name ( Synonym ) Chemical Name Chemical Structure Study Type MRID Maximum

%AR 1 (day) Final %AR 1 (day)

Terbufoxon

s ulfoxide (CL94365) S

- [[(1,1

- dimethylethyl)sulfinyl]methyl] O,O

- diethylphosphorothioate

Formula: C 9 H 21 O 4 P 1 S 2 MW: 288.36 g/mol

SMILES: C(C)(C)(C)S(=O)CSP(=O)(OC C)OCC Aerobic s oil 00156853 0.5 (7 d) ND (365 d)

Anaerobic s oil 41749801 2.6 (60 d) 2.6 (60 d)

Terbufoxon s ulfone (CL94302) S

- [[(1,1

- dimethylethyl)sulfonyl]methyl] O,O

- diethylphosphorothioate

Formula: C 9 H 21 O 4 P 1 S 2 MW: 304.36 g/mol

SMILES: C(C)(C)(C)S(=O)(=O)CSP(=O) (OCC)OCC Anaerobic s oil 41749801 3.1 (30 d) 2.0 (60 d)

Des

- ethyl t erbufos

s ulfoxide (CL 1008534) S

- [[(1,1

- dimethylethyl)sulfonyl]methyl] O,O

- diethyl ester

Formula: C 7 H 17 O 3 P 1 S 3 MW: 276.37 g/mol

SMILES: C(C)(C)(C)S(=O)CSP(O)(=S)O

CC Aerobic a quatic 44862502 2 2.14 (7 d) ND (30 d)

### 56 Common Name ( Synonym ) Chemical Name Chemical Structure Study Type MRID Maximum

%AR 1 (day) Final %AR 1 (day)

Des

- ethyl t erbufos

s ulfone (CL 1008533) S

- [[(1,1

- dimethylethyl)sulfonyl]methyl]

O

- ethyl ester

Formula: C 7 H 17 O 4 P 1 S 3 MW: 276.37 g/mol

SMILES: C(C)(C)(C)S(=O)(=O)CSP(O)( =S)OCC Aerobic a quatic 44862502 2 2.85 (14 d) ND (30d)

Unextracted R esidues

Unextracted

residues NA NA Anaerobic s oil 41749801 9.2 (60 d) 9.2 (60 d)

NA = not applicable; NR = not reported ; ND = not detected

BOLD = formation > 10% of that applied

1 Applied r adioactivity

2 No sediment was used in the study

.

3 Designated as “ Degradate A ” in hydrolysis study

.

### 57 Appendix C : Submitted Toxicity Data

Table C

- 1 . Summary of Toxicity of Terbufos to Aquatic Animals

Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAEC /LOAEC

for acute studies

Bluegill sunfish ( Lepomis

macrochirus ) 96 hr (static) 86 LC 50 = 0.77 (0.72

- 0.83) 1 μg ai/L (nom) 2

Probit slope = 14.35 (8.33

- 20.38) 1

Sublethal effects: pectoral fin erection

, and partial loss of equilibrium 00087718 Very Highly

Toxic Supplemental (test

concentrations

were not measured) Unknown if sublethal

effects observed in surviving fish.

NOAEC = 0.37 μg ai/L

LOAEC = 0.65 μg ai/L (mortality and sublethal effects)

86.3 LC 50 = 3.8 (2.8

- 4.9) 1 μg ai/L (nom) (binomial test) 00037483 Very Highly

Toxic Supplemental (test

concentrations

were not measured) No sublethal effects reported for surviving

fish.

NOAEC = 2.8 μg ai/L

LOAEC = 3.7 μg ai/L (mortality)

96 hr (flow

through) 88.6 LC 50 = 0.87 (0.77

- 1.0) 1 μg ai/L (nom) 2

Probit slope = 5.48 (3.69

- 7.28) 1 00085176 Very Highly

Toxic Supplemental (test

concentrations

were not measured) No sublethal effects reported for surviving

fish.

NOAEC = 0.32 μg ai/L

LOAEC = 0.42 μg ai/L (mortality)

96 hr (static) 88 LC 50 = 1.1 (0.8

- 1.6) 1 μg ai/L (nom) 40098001 Very Highly

Toxic Myer and Ellersieck,

1986 Sublethal effects and NOAEC not reported.

9 independent tests;

96 hr LC 50 ranged from 1.1 to 2.4 μg ai/L (nom)

15 LC 50 = 1.7 (1.2

- 2.4) 1 μg ai/L (nom) Sublethal effects and NOAEC not reported.

LC 50 = 12.3 (9.8

- 15.2) 1 μg formulation/L (nom)

Probit slope = 5.4 (3.1

- 7.6) 1

LC 50 = 1.8 (1.5

- 2.3) 1 μg ai/L (nom) FE0TER04 Very Highly

Toxic Supplemental (test

concentrations

were not measured) Counter 15G

No sublethal effects reported.

NOAEC = 3.7 μg formulation/L

LOAEC = 5.6 μg

formulation/L (mortality)

NA NA NOAEC = 0.10 μg

ai/L 3 NA NA NA Acute to Chronic ratio

based on rainbow trout

data.

### 58 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAEC /LOAEC

for acute studies

Brown trout ( Salmo trutta ) 96 hr (static) 86 LC 50 = 20 (12

- 34) 1 μg ai/L (nom) 2

Probit slope = 1.47 (0.95

- 1.98) 1

Sublethal effects: partial loss of equilibrium 00087718 Very Highly

Toxic Supplemental (test

concentrations

were not measured) Unknown if sublethal

effects observed in surviving fish

.

NOAEC = 3.2 μg ai/L

LOAEC = 10 μg ai/L (mortality and

sub lethal effects)

Channel Catfish ( Ictalurus

punctatus ) 144 hr (flow

through) 88.6 LC 50 = 9.6 (8.5

- 11.07) 1 μg ai/L (nom) (moving average) 2 00085176 Very Highly

Toxic Supplemental (test

concentrations

were not measured) No sublethal effects reported for surviving

fish

.

NOAEC = 4 μg ai/L

LOAEC = 5 μg ai/L (mortality)

Test conducted for 144 hrs. Toxicity at 144 hrs was slightly greater than at 96 hrs.

96 hr (static) 15 LC 50 = 1800 (1230

- 2640) 1 μg ai/L (nom) 40098001 Moderately

Toxic Myer and Ellersieck,

1986 Sublethal effects and NOAEC not reported.

Fathead minnow ( Pimephales promelas ) 96 hr (static) 88 LC 50 = 390 (237

- 643) 1 μg ai/L (nom) 40098001 Highly

Toxic Myer and Ellersieck,

1986 Sublethal effects and NOAEC not repo rted.

15 LC 50 = 150 (101

- 223) 1 μg ai/L (nom)

Rainbow trout ( Oncorhynchus mykiss or Salmo gairdneri* ) 96 hr (static) 86.3 LC 50 = 9.4 (7.7

- 11.4) 1 μg ai/L (nom)

Probit slope = 6.2 (3.4

- 8.9) 1 μg ai/L 00037483 Very Highly

Toxic Supplemental (test

concentrations

were not measured) No sublethal effects reported for surviving

fish.

NOAEC = 4.9 μg ai/L

LOAEC = 7.5 μg ai/L (mortality)

*Salmo gairdneri

88 LC 50 = 7.6 (6

- 9.7) 1 μg ai/L (nom)

40098001 Very Highly

Toxic Myer and Ellersieck,

1986 Sublethal effects and NOAEC not reported.

9 independent tests;

96 hr LC 50 ranged from 7.6 to 15.3 μg ai/L (nom)

*Salmo gairdneri

15 LC 50 = 8.8 (6.4

- 12.1) 1 μg ai/L (nom) Sublethal effects and NOAEC not reported.

*Salmo gairdneri

### 59 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAEC /LOAEC

for acute studies

Rainbow trout ( Oncorhynchus mykiss or Salmo gairdneri* ) 96 hr (static) 15 LC 50 = 59.7 (48.1

- 74.3) 1 μg formulation/L (nom)

Probit slope = 5.5 (3.2

- 7.9) 1 μg formulation/L

LC 50 = 8.9 (7.2

- 11.1) 1 μg ai/L (nom) FE0TER05 Very Highly

Toxic Supplemental (test

concentrations

were not measured) Counter 15G

No sublethal effects reported for surviving

fish

.

NOAEC = 21 μg formulation/L

LOAEC = 32 μg

formulation/L (mortality)

*Salmo gairdneri

ELS 98.5 NOAEC ≥ 1.4 μg ai/L (mm) 40009301 NA Supplemental *Salmo gairdneri

98.99 NOAEC = 0.64 μg ai/L (mm)

LOAEC = 1.4 μg

ai/L (mm) based on reduced wet weight and length 41475802 NA (“Core”) Acceptable Effects at highest two

test concentrations (2.7 and 5.3 μg ai/L): reduced survival, resting on lateral surfaces, hypersensitivity, loss of equilibrium, irregular respiration,

dark discoloration, surfacing, and quiescence. Several

fish at various

concentrations developed spinal

curvature and

malformed otic capsules.

*Oncorhynchus mykiss

### 60 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAEC /LOAEC

for acute studies

Waterflea (Daphnia magna) 48 hr (static) 88.6 EC 50 = 0.17 (0.15

- 0.19) 1 μg ai/L (mm)

Sublethal effects: erratic swimming, lying on bottom. 00101495 Very Highly

Toxic Supplemental (test material was unstable) Majority of the daphnids displaying

sublethal effects were

deceased at 48 hr.

NOAEC = 0.107 μg ai/L

LOAEC = 0.185 μg ai/L (mortality and

sublet hal effects)

88 EC 50 = 0.4 (0.3

- 0.5) 1 μg ai/L (nom) 40098001 Very Highly

Toxic Myer and Ellersieck,

1986 Sublethal effects and NOAEC not reported.

15 EC 50 = 6.2 (5.1

- 7.7) 1 μg formulation/L (nom)

Probit slope = 6.6 (3.5

- 9.6) 1

EC 50 = 0.9 (0.8

- 1.2) 1 μg ai/L (nom) FE0TER06 Very Highly

Toxic Supplemental (test

concentrations

were not measured) Counter 15G

Sublethal effects not reported.

NOAEC = 2.1 μg formulation/L

LOAEC = 3.2 μg

formulation/L (mortality)

21 day

Life

Cycle (flow

through) 98.4 NOAEC = 0.030 μg ai/L (mm)

LOAEC = 0.076 μg ai/L (mm) based on growth and reproduction (reduced body length

and number of offspring) 00162525 NA (“Core”) Acceptable Some daphnids were observed lying on the bottom/ quiescent on day 19; those organism appear to

have been deceased by day 21. Two additional daphnids

showed the same effects on day 21.

Gammarus pseudolimnaeus 96 hr (static) 88 LC 50 = 0.20 (0.1

- 0.3) 1 μg ai/L (nom) 40098001 Very Highly

Toxic Myer and Ellersieck,

1986 Sublethal effects and

NOAEC not reported.

Chironomus plumosus 48 hr (static) 88 EC 50 = 1.4 (1.0

- 2.0) 1 μg ai/L (nom) 40098001 Very Highly

Toxic Myer and Ellersieck,

1986 Sublethal effects and NOAEC not reported.

Crayfish ( Procambarus

clarkii ) 96 hr (flow through) 88.6 LC 50 = 8.0 (6.9

- 10.2) 1 μg ai/L (nom) 2

Probit slope = 3.36 (2.34

- 4.38) 1 00085176 Very Highly

Toxic Supplemental (test

concentrations

were not measured) No sublethal effects reported for surviving crayfish

.

NOAEC = 2.4 μg ai/L

LOAEC = 3.2 μg ai/L (mortality)

### 61 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAEC /LOAEC

for acute studies

Sheepshead

minnow ( Cyprinodon variegatus ) 96 hr (static) 98.4 LC 50 = 1.6 (0.77

- 3.2) 1 μg ai/L (mm) (binomial test)

Sublethal effects: surfacing, loss of equilibrium, and fish

at the bottom of the

test chamber. 00162524 Very Highly

Toxic Supplemental (due to low

dissolved

oxygen concentrations at 96 hr) NOAEC < 0.37 μg ai/L

LOAEC ≤ 0.37 μg ai/L (sublethal effects)

At the lowest test concentration,

sublethal effects (only observed at 96 hr) may have been

due to stress from

low dissolved

oxygen, terbufos, or

both.

96 hr (flow

through) 98 LC 50 = 3.2 (2.7

- 3.7) 1 μg ai/L (mm)

Probit slope = 7.1 (3.8

- 10.4) 1 μg ai/L

Sublethal effects: loss of equilibrium, floating at the surface, forward pointing pectoral fins, erratic swimming, labored respiration, quiescence, fish at

the bottom of the test chamber, and surfacing. 41373602 Very Highly

Toxic (“Core”) Acceptable NOA EC < 1.4 μg ai/L

LOAEC ≤ 1.4 μg ai/L (sublethal effects)

NA NA NOAEC = 0.14 μg

ai/L 4 NA NA NA Acute to Chronic ratio

based on rainbow trout

data.

Mysid shrimp ( Americamysis

bahia ) 96 hr (static) 98.4 LC 50 = 0.22 (0.14

- 0.35) 1 μg ai/L (mm)

Probit slope = 2.51 (1.44

- 3.58) 1

Sublethal effects: quiescence, lying on bottom, and surfacing 00162523 Very Highly

Toxic Supplemental (M RID

00162523 and

41297903 primarily due

to excessive

control mortality in

either the negative or

solvent

control but not both) NOAEC = 0.07 μg ai/L

LOAEC = 0.13 μg ai/L (mortality and sublethal effects; taking control mortality into consideration)

Sublethal effects

observed at 0.13 to 0.59 μg ai/L.

### 62 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAEC /LOAEC

for acute studies

Mysid shrimp ( Americamysis

bahia ) 96 hr (flow

through) 98 LC 50 = 0.40 (0.34

- 0.48) 1 μg ai/L (mm) (moving average)

Sublethal effects: quiescence, lying on bottom, surfacing,

and loss of equilibrium 41297903 Very Highly

Toxic Supplemental (see MRID

00162523

above) NOAEC = 0.15 μg ai/L

LOAEC = 0.24 μg ai/L (mortality; taking control mortality into consideration)

Sublethal effects

observed at 0.35 and 0.71 μg ai/L.

99.9 LC 50 = 0.543 (0.474

- 0.623) 1 μg ai/L (mm) ( Untrimmed Spearman

- Kärber)

Sublethal effects: erratic swimming, gyrating motions,

and lethargy 42306701 Very Highly

Toxic Acceptable NOAEC = 0.225 μg ai/L

LOAEC = 0.441 μg ai/L (mortality and sublethal efffects)

NA NA NOAEC = 0.041 μg/L 5 NA NA NA Acute to Chronic

ratio based on daphnia data.

Eastern oyster ( Crassostrea virginica ) 96 hr (flow

through) 89.2 EC 50 = 201 μg ai/L (176

- 231) 1 μg ai/L (mm) (moving average) 42381501 Highly

Toxic (“Core”) Acceptable NOAEC < 54 μg ai/L (22 to 29% inhibition compared to negative

control at lowest three test levels)

mm = mean measured; nom = nominal concentration ; NA = not applicable

– See DERs for more complete explanations of study classifications.

1 Range is 95% confidence interval.

2 It is u ncertain if test concentrations were adjusted for purity of the test material.

3 Bluegill sunfish sensitivity to terbufos on a chronic basis was estimated using an acute to chronic ratio (ACR) because it is the most acutely sensitive species. The ACR was based on rainbow trout (acute and chronic toxicity) and bluegill sunfish (acute toxicity) data. Numerous acute TGAI toxicity endpoints were available for rainbow trout (10) and bluegill sunfish (1 2 ) from reliable studies. An average toxicity value from these studies was used given that the range was 2X (rainbow trout) to 3X (b luegil l sunfish), resulting in an ACR of 16.7. One open literature study (Call et. al, 1989) reported a NOAEC (0.34 μg ai/L ) for fathead

minnow about two times lower than that of the rainbow trout (0.64 μg ai/L

, MRID 41475802). The study by Call et al. was clas sified as qualitative and was not used to calculate an ACR. Nonetheless, results from the Call et al. study support the ACR based on the rainbow trout data; an ACR of 4.5 was reported for fathead minnow based on exposure to terbufos while a mean ACR

of 10 .4 (range of 4.5 to 27.9) was reported for fathead minnow based on terbufos plus four other organophosphate chemicals. The reported ACR of 4.5 is based on a NOAEC of 1.96 μg ai/L because Call et al. questioned the biological significance of the observed effects on length at lower concentrations; the ACR was 38.2 assuming a NOAEC of 0.34 μg ai/L.

4 Sheepshead minnow sensitivity to terbufos on a chronic basis was estimated using an ACR because data were not available. The ACR was based on rainbow trout (ac ute and chronic toxicity) and sheepshead minnow (acute toxicity) data. See footnote 3 regarding use of rainbow trout data to estimate the ACR of 16.7. Two equally reliable acute studies were available for sheep shead minnow; an average acute toxicity valu e from these studies was used to estimate chronic toxicity to sheepshead minnow given that the range of acute toxicity values was 2X.

5 Mysid sensitivity to terbufos on a chronic basis was estimated using an ACR because data were not available. The ACR was based on daphnia (acute and chronic toxicity) and mysid (acute toxicity) data. Two equally reliable acute studies with the TGAI were available for daphnia and three were available for mysid . A n average acute toxicity value was used for each species when calculating the ACR given the small range of acute values (2.4X for daphnia and 2.5X for mysid)

.

### 63 Table C

- 2 . Summary of Toxicity of Terbufos to Aquatic Plants

Species Exposure

Scenario %

AI Toxicity MRID Toxicity Category Classification

Freshwater Algae ( Pseudokirchneriella subcapitata) 96 hr (static) 89.3 EC 50 >1.85 mg ai/L (im)

NOAEC = 0.399 mg ai/L (im)

LOAEC = 1 mg ai/L based on effects to cell density, area under the growth curve, average specific growth rate, and yield. 48689902 NA Acceptable

Marine Diatom ( Skeletonema grethae ) 96 hr 89.3 EC 50 > 1.01 mg ai/L (im)

NOAEC ≥ 1.01 mg ai/L (im) 48939101 NA Supplemental (numerous deviations including excessive

variation of initial cell density among treatment groups)

Duckweed (Lemma gibba ) 7 day 89.3 EC 50 > 4.20 mg ai/L

NOAEC = 0.280 mg ai/L

LOAEC = 0.630 mg ai/L based on frond number, growth rate of frond number, and yield of frond

number 48689901 NA Acceptable

im = initial measured ; NA = not applicable

– See DERs for more complete explanations of study classifications.



### Table C

- 3 . Summary of Toxicity of Terbufos to Terrestrial Animals

Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Northern Bobwhite Quail ( Colinus virginianus ) Single oral

dose 89.6 LD 50 =28.6 (22.2

- 55.9) 1 mg ai/kg bw

Probit slope = 4.35 (1.56

- 7.13)

Sublethal effects: clinical signs (lethargy progressing to depression, reduced

reaction to external stimuli, loss of coordination, lower limb weakness, prostrate posture, loss of righting reflex, salivation, and lower limb rigidity) 00106551 Highly

toxic (“Core”) Acceptable Sublethal effects

observed at some point during the exposure period at

all dose s (≥ 6.81 mg ai/kg bw). Mortality

observed at doses ≥ 14.7 mg ai/kg

bw

.

### 64 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Northern Bobwhite Quail ( Colinus virginianus ) Single oral

dose 20 LD 50 = 250 (147

- 464) 1 mg formulation/kg bw

LD 50 = 50 (29.4

- 92.8) 1 mg ai/kg bw

Sublethal effects: clinical signs (ataxia, lethargy, inability to walk when aroused, and weakness), reduced body weight, and

decreased food consumption (day 1

- 3,

all test concentrations with surviving birds) 40660708 Highly

toxic (ai basis) (“Core”) Accep table Counter 20P

NOAEL < 29.4 mg ai/kg bw

LOAEL ≤ 29.4 mg ai/kg bw (sublethal effects)

Body weight

decreased in all

treatment groups from day 1

- 3 or 7. Body weight

increased thereafter, recovering to that of control birds by day 21 in the

second and thir d highest treatment groups (higher
treatment groups
showed 100% mortality).

LD 50 = 238 (180

- 310) 1 mg formulation/kg bw

LD 50 = 47.6 (35.9

- 62) 1 mg ai/kg bw

Probit slope = 3.52 (1.99

- 5.04)

Sublethal effects: clinical signs at unspecified treatment

levels (lethargy, ataxia, diarrhea, anorexia, noticeable weight loss, inability to stand, and weak appearance) and reduced body weight and feed consumption in all treatment groups 41508802 Highly

toxic (ai basis) Acceptable Counter CR

NOAEL < 20 mg ai/kg bw

LOAEL ≤ 20 mg ai/kg bw (mortality, body weight, and feed consumption)

### 65 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Northern Bobwhite Quail ( Colinus virginianus ) Single oral

dose 15 LD 50 = 295 (215

- 464) 1 mg formulation/kg bw

LD 50 = 44.3 (32.3

- 69.6) 1 mg ai/kg bw

Sublethal effects: clinical signs (ataxia, lethargy, inability to

stand/walk when aroused, dyspnea, muscle tremors, piloerection, and paralysis), reduced body weight, and reduced food consumption (day

1

- 3 or 7, all test concentrations) 40660707 Highly

toxi c (ai basis) (“Core”) Acceptable Counter 15G

NOAEL < 22.1 mg ai/kg bw

LOAEL ≤ 22.1 mg ai/kg bw (sublethal effects)

Body weight

decreased in all

treatment groups from day 1

- 3. Body weight

increased thereafter but by day 21 only the

lowest treatment

group weight

recovered to that

of the control

birds.

LD 50 = 290 (245

- 344) 1 mg formulation/kg bw

LD 50 = 43.5 (36.7

- 51.6) 1 mg ai/kg bw

Probit slope = 8.61 (4.31

- 12.9)

Sublethal effects: clinical signs in all

treatment groups (lethargy, ataxia, diarrhea, anorexia, and inability to walk) and

reduced feed consumption in the highest three test

concentrations not showing 100% mortality (day 0

- 3) 41508803 Highly

toxic (ai basis) Acceptable Counter 15G

NOAEL < 15 mg ai/kg bw

LOAEL ≤ 15 mg ai/kg bw (clinical sig ns)

### 66 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Northern Bobwhite Quail ( Colinus virginianus ) 8 days (5 days

treatment and 3 days observation) 86 LC 50 = 143 (103

- 214) 1 ppm ai (moving average) (nom) 2

Sublethal effects:

decreased locomotor activity, feather erection, loss of righting reflex, and reduced food consumption 00087717 Highly

toxic Supplemental (test

concentrations

not measured

or demonstrated to be stable) NOAEC < 25 ppm

ai

LOAEC ≤ 25 ppm ai (mortality and sublethal effects)

87.8 LC 50 = 157 (125

- 201) 1 ppm ai (nom)

Probit slope = 7.2 (3.2

- 11.2)

Sublethal effects: depression (lethargy),

reduced reaction to sound and movement, wing droop, loss of coordination, prostrate posture, lower limb rigidity, ruffled appearance, lower limb weakness, reduced body weight gain, and

reduced food

cons umption 00160387 Highly

toxic Supplemental (test

concentrations

not measured

or demonstrated to be stable) NOAEC = 56.2 ppm ai

LOAEC = 100 ppm ai (mortality and clinical signs)

Some sublethal

effects disappeared by the

end of the experiment.

One

generation Reproduction Study 89 NOAEC < 2 ppm ai (nom) 2 00085177

NA Supplemental (test

concentrations

not measured

or demonstrated

to be stable

and lack of

pen

- by

- pen data ) Possible effects on viable embryos of eggs set at 2 ppm

ai. Results cannot

be confirmed due to a lack of pen by pen data for statistical analysis.

89.6 NOAEC ≥ 30 ppm ai (nom) 00161573 (“Core”) Acceptable No effects

observed at highest test

concentration.

### 67 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Mallard Duck ( Anas platyrhynchos ) Single oral

dose 20 LD 50 = 161 (68

- 316) 1 mg formulation/kg bw

LD 50 = 32.2 (13.6

- 63.2) 1 mg ai/kg bw

Sublethal effects: lethargy, ataxia, and

reduced food consumption (day 0

- 3, all test concentrations) 40660706 Highly

toxic (ai basis) (“Core”) Acceptable Counter 20P

NOAEL < 13.6 mg ai/kg bw

LOAEL ≤ 13.6 mg ai/kg bw (reduced food consumption)

15 LD 50 = 88 (0

- 215) 1 mg formulation/kg bw

LD 50 = 13.2 (0

- 32.3) 1 mg ai/kg bw

Sublethal effects: dyspnea, lethargy, immobility, emesis, and

reduced food consumption (day 0

- 3, all test concentrations) 40660705 Highly

toxic (ai basis) (“Core”) Acceptable Counter 15G

NOAEL < 6.96 mg ai/kg bw

LOAEL ≤ 6.96 mg ai/kg bw (mortality and sublethal effects)

Mallard Duck ( Anas platyrhynchos ) 8 days (5 days

treatment and 3 days observation) 86 LC 50 = 153 (117

- 198) 1 ppm ai (nom) 2

Probit slope = 5.45 (2.33

- 8.57)

Sublethal effects:

decreased locomotor activity, feather erection, loss of righting reflex, and reduced food consumption (all test concentrations) 00087717 Highly

toxic Supplemental (test

concentrations

not measured

or demonstrated to be stable) NOAEC < 100 ppm ai

LOAEC ≤ 100 ppm ai (mortality

and sublethal effects)

Increasing food

avoidance with increasing dose

86 LC 50 = 697 (584

- 1616) 1 ppm ai (moving average) (nom) 2

Sublethal effects: reduced body weight and food consumption (all test concentrations) 00035120 Moderately

toxic Supplemental NOAEC < 100 ppm ai

LOAEC ≤ 100 ppm ai (sublethal effects)

Body weight and food consumption showed recovery after exposure period

Study author

calculat ed LC 50 = 520 ppm ai

### 68 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Mallard Duck ( Anas platyrhynchos ) One

generation Reproduction Study 89 NOAEC < 2 ppm ai (nom) 2 00097892

NA Supplemental (test

concentrations

not measured

or demonstrated

to be stable

and lack of

pen

- by

- pen data ) Possible effects on viable embryos of eggs set at 2 ppm

ai and other

variables at 20 ai ppm. Results

cannot be

confirmed due to a lack of pen by pen

data for statistical analysis. It is also noted that body weight decreased at 2 and 20 ppm ai

and increas ed in

the control throughout the study.

89.6 NOAEC = 5 ppm ai (nom)

LOAEC = 15 ppm ai (nom) * 00161574 (“Core”) Acceptable *Possible biologically significant (but not statistically significant) effect on embryo viability.

Domestic Hen ( Gallus gallus

domesticus ) Single oral

dose 88.8 NA 46293202 NA Invalid

Brown

- headed

Cowbird ( Molothrus ater ) Single oral

dose 20 LD 50 = 85 (46

- 151) 1 mg formulation/kg bw

LD 50 = 16.9 (9.2

- 30.1) 1 mg ai/kg bw

Probit slope = 1.59 (0.81

- 2.37)

Sublethal effects:

clinical signs at unspecified treatment levels (lethargy, hypersalivation, ataxia, inability to walk or fly, shaking, lying on the side, tachypnea, and agape mouth) and body weight (increase only) 41508804 Highly

toxic (ai basis) Acceptable Counter CR

NOAEL < 3.5 mg ai/kg bw

LOAE L ≤ 3.5 mg ai/kg bw (mortality)

### 69 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Brown

- headed

Cowbird ( Molothrus ater ) Single oral

dose 15 LD 50 = 148 (100

- 235) 1 mg formulation/kg bw

LD 50 = 22.2 (15.0

- 35.3) 1 mg ai/kg bw

Probit slope = 2.63 (1.46

- 3.79)

Sublethal effects: clinical signs showed remission by day 4 (lethargy, hypersalivation, ataxia, anorexia, difficulty or inability walking or flying, and agape mouth), and reduced feed consumption occurred intermittently at the top two doses 41508805 Highly

toxic (ai basis) Acceptable Counter 15G

NOAEL = 6.96 mg ai/kg bw

LOAEL = 10.2 mg ai/kg bw (mortality and clinical signs)

Honeybee ( Apis mellifera ) Acute contact T GAI LD 50 = 4.09 μg ai/bee

Probit slope = 3.54 μg

ai/bee 00066220 Moderately

toxic (“Core”) Acceptable

### 70 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Rat Acute Oral 89.7 LD 50 = 1.25 (0.98

- 1.52) 1 mg ai/kg bw (female)

LD 50 = 2.87 (2.33

- 4.30) 1 mg ai/kg bw (male)

Sublethal effects: tremors, salvation, exophthalmos, and decreased activity. All survivors appeared normal 9 days after dosing. 44021601 Very Highly

Toxic Acceptable

19 LD 50 = 0.836 mg ai/kg bw (female)*

LD 50 = 3.3 mg ai/kg bw (male)

Sublethal effects: tremors, exophthalmos, salivation, chromodacyrorrhea, ventral surface staining, diarrhea, decreased activity, blood around nose, diuresis, and

ataxia 47512801 Very Highly

Toxic Acceptable Counter 20G

Sublethal effects

were observed in

animals that did not survive except

for males in the 2.4 mg ai/kg bw (12.5 mg/kg bw)

dose level. Recovery of those animals generally

occ urred by three days after dosing.

*Confidence

intervals could not

be calculated due

to 0 and 100% mortality for sequential doses ( e.g. , 0% mortality at 0.59 mg ai/kg

bw and 100% mortality at 1.18 mg ai/kg bw for females).

### 71 Species Exposure

Scenario % AI Toxicity MRID Toxicity Category Classification Comments and

NOAE L /

LOAE L or

NOAEC/

LOAEC for

acute studies

Rat 2

- generation reproduction 89.6 Reproductive Effects NOAEC(L) = 1 ppm ai (0.07

– 0.09 mg ai/kg bw/day)

LOAEC(L) = 2.5 ppm ai (0.18

– 0.24 mg ai/kg bw/day) based on decreased pregnancy rate and male fertility

Maternal/Offspring Effects NOAEC(L) = 1 ppm ai (0.09 mg ai/kg bw/day)

LOAEC(L) = 2.5 ppm ai (0.22

– 0.24 mg ai/kg bw/day) based on decreased body weight gain in adult females during lactation and lower pup weights 43649402 NA Acceptable Cholinesterase

inhibition NOAEC(L) = 0.5 ppm ai (0.04 mg ai/kg bw/day)

LOAEC(L) = 1

ppm ai (0.09 mg ai/kg bw/day)
based on ≥ 50%

inhibition in female plasma

levels

Range of dose per body weight reflects weights of study animals (male and female)

1 Range is 95% confidence interval.

2 It is uncertain if test concentrations were adjusted for purity of the test material.

NA = n ot applicable

– See DERs for more complete explanations of study classifications.



### Table C

- 4 . Summary of Toxicity of Terbufos to Terrestrial Plants

Species Exposure

Scenario %

AI Toxicity MRID Toxicity Category Classification

Cabbage, Carrot, Cucumber, Lettuce, Soybean, Tomato, Corn, Oat, Onion, and Ryegrass Tier 1 Seedling Emergence 89.3 EC 25 >2.04 lb ai/A (m)

NOAEC = 2.04 lb ai/A

Applies to monocots and

dicots 48710801 NA Supplemental (tested TGAI

instead of TEP and

tested fewer than the

minimum

recommended number of seeds per

treatment level)

m = measured ; NA = not applicable

– See DER for more complete explanations of study classifications.

### 72 Appendix D : Summary of Mixture Toxicity Data

Table D

- 1 . Summary of Open Literature Studies on Toxicity of Mixtures 1 

### of Terbufos and Other Pesticides 2



### Citation Chemicals tested 1 

### Test species Summary 3

Baerg, 1994 Terbufos, Terbufos Sulfone, Nicosulfuron, Chlorimuron,
Bentazon, Imazethapyr, Malathion, and

Cinnamic Acid Corn Terbufos inhibited nicosulfuron metabolism in corn. Terbufos sulfone

inhibited the metabolism of nicosulfuron and imazethapyr but not bentazon in corn. Terbufos sulfone inhibited P450 activity; that is, the hydroxylation of nicosulfuron, chlorimuron, bentazon, and imazethapyr (but not cinnamic acid) and the desulfuration of malathion in corn.

Biales et al.

, 20 1 1 Terbufos and

Permethrin Fathead minnow I ncreased mortality was observed in the mixture compared to only terbufos or permethrin exposure

. Twenty

- four proteins were found to be differentially expressed among all three treatments (mixture, only terbufos, and only permethrin).

C astro

- Escobar et al.

, 1996 Terbufos

, Nicosulfuron, and

Primisulfuron Corn ( Zea mays ) Corn i njury from nicosulfuron and primisulfuron increased with an increased application rate of terbufos. Plant height following application of nicosulfuron and primisulfuron showed an inverse relationship with increased application rate of terbufos (i.e., plant height decreased with increased terbufos rate). Choung et al.

, 2011 a T erbufos sulfone and

A trazine Southern Bell Frog The authors concluded that atrazine did not interact synergistically with

terbufos sulfone. Terbufos sulfone alone and as a mixture significantly slowed larval development and ultimately delayed metamorphosis. Choung et al.

, 2010 Terbufos, Terbufos sulfone, Terbufos sulfoxide, and Atrazine Chironomus tepperi No interaction was observed between atrazine (25 μg/l ) and mixtures with either terbufos, terbufos sulfone, or terbufos sulfoxide

.

Choung et al.

, 2011 b Terbufos , Terbufos sulfone, Terbufos sulfoxide, and Atrazine Ceriodaphnia dubia The addition of atrazine (10 μg/l) significantly increased the toxicity of terbufos. The toxicity of terbufos sulfone was unaffected by atrazine, whereas the results for terbufos sulfoxide were equivocal.

Diehl et al.

, 1995 Terbufos and

Nicosulfuron Corn ( Zea mays ) Fresh corn weight was reduced more from exposure to a mixture of terbufos and nicosulfuron than to exposure of either terbufos or nicosulfuron alone.

Plant metabolism of n icosulfuron was slowed by the presence of terbufos

.

### 73 Citation Chemicals tested 1 

### Test species Summary 3

Diehl and Stoller

, 1995 Terbufos and

Nicosulfuron Corn ( Zea mays ) Terbufos, applied to the soil at planting, interacted with nicosulfuron applied postemergence to injure corn and reduce grain yield. No visual injury or yield reductions were noted in corn treated with nicos ulfuron alone. The

t erbufos 15G formulation caused greater corn injury than did the Counter

20 CR (terbufos) formulation at each rainfall timing when sprayed with

nicosulfuron

. Downard et al.

, 199 9 Terbufos, T risulfuron,

D esmedipham, and,

P henmedipham Sugar beet ( Beta vulgaris) In some cases t oxicity to sugar beet (% injury) was significantly increased when plants were exposed to terbufos + trisulfuron and terbufos + trisulfuron + desmedipham + phenmedipham compared to exposure to

individual chemicals or the herbicides mixture. The impact of the mixture (enhanced toxicity or no effect vs exposure to individual chemicals or herbicide mixtures) varied by factor s including experimental site location and year, pesticide application concentration, terbufos formulation, and terbufos application method. Mixtures did not increase adverse effects on

po pulation number, root yield, sucrose content, or extractable sucrose. Exposure to terbufos + desmedipham + phenmedipham did not result in

enhanced or decreased to xicity to any measured endpoint. In a few cases, exposure to terbufos + herbicide(s) increased root yield, sucrose content,

and/or extractable sucrose.

Fo ster and Brust,

1995 T erbufos and Methyl

bromide Watermelon citrullus

lanatus ; striped and spotted cucumber

beetle Watermelon growth and yield were similar in terbufos only treatments and

controls

. Exposure to a mixture of methyl bromide and terbufos resulted in similar watermelon growth and yield as exposure to methyl bromide alone.

Frazi er and Nissen,

1994 Terbufos, Benoxacor,

CGA

- 185072 , MON

13900, and

P rimisulfuron Corn ( Zea mays ) E xposure to a mixture of primisulfuron and terbufos reduced shoot dry weight and shoot length compared to the negative control and either compound alone

. Preemergence application s of the safeners CGA

- 185072

and MON

- 13900 significantly reduced stunting effect s on corn from the

combined exposure to primisulfuron and terbufos ; however, shoot weight and length remained reduced compared to the negative control

. Benoxacor had no safening effect.

Gr een and Ulrich,

1994 Terbufos and

Rimsulfuron C orn ( Zea mays ; inbred and hybrid

varieties ) Terbufos applied with rimsulfuron significantly reduce d growth (weight) in

three of four varieties of corn compared to exposure to either compound

alone

. Hein and Wilson,

1995 Terbufos, Cycloate, Ethofumesate, and Diethatyl Sugar beet Yields decreased when terbufos was applied with cycloate treated plots. On ethofumesate and diethatyl treated plots, root yield also decreased.

Holshouser et al.

, 1991 T erbufos and CGA

136872 (sulfonylurea herbicide) Corn (five hybrids ) All hybrids showed increased injury and reduced yield after CGA

- 136872 was applied in combination with terbufos ( in

- furrow application). Injury

increased with increased application rate of CGA

- 136872

.

### 74 Citation Chemicals tested 1 

### Test species Summary 3

Kap usta and Krausz,

1992 Terbufos and

Nicosulfuron Corn ( Zea mays ) Terbufos applied in

- furrow at planting interacted with nicosulfuron applied

post to cause significant injury 25 to 60 d ays after planting in 1989 and

1990. Injury decreased significantly when nicosulfuron was applied at later growth stages of corn. Plant population was not affected by the combined

exposure to terbufos and nicosulfuron. Corn ear number and grain yield in

19 89 and 1990 were lower in plots treated with terbufos at planting and nicosulfuron applied at the three leaf stage than in plots treated with only nicosulfuron. There were no differences in the height of corn, ear number, or grain yield when nicosulfuron w as applied at the seven

- leaf stage regardless of terbufos application in 1989 and 1990.

Kwon et al.

, 1995 T erbufos

, N icosulfuron,

P rimisulfuron, and

P iperonyl butoxide (PBO) Corn (six hybrids) Toxicity to corn (reduced height and /or increased % injury) increased when plants were exposed to terbufos + nicosulfuron, terbufos + primisulfuron,

t erbufos + nicosulfuron + PBO, and terbufos + primisulfuron + PBO compared to toxicity of single chemicals. Toxicity of terbufos + PBO was not enhanced comp ared to toxicity of each chemical alone.
Kwon, 1993 Terbufos, Metolachlor, Alachlor, Acetochlor,

C hlorimuron, Nicosulfuron, Primisulfuron, Imazaquin

, and antidotes (CGA

154281 and naphthalic anhydride ) Corn Toxicity to corn (reduced height and/or increased % injury) was increased when plants were exposed to terbufos + chlorimuron, terbufos + nicosulfuron, terbufos + primisulfuron, terbufos + chlorimuron + metolachlor, terbufos + nicosulfuron + metolachlor, te rbufos + primisulfuron + metolachlor, terbufos + chlorimuron + metolachlor + CGA

- 154281,

terbufos + nicosulfuron + metolachlor + CGA

- 154281, terbufos + primisulfuron + metolachlor + CGA

- 154281, terbufos + nicosulfuron + naphthalic anhydride, and terbufos + primisulfuron + naphthalic anhydride compared to toxicity of each chemical (or combination of chemicals when applicable ) alone. Toxicity to corn from exposure to terbufos + metolachlor,

terbufos + alachlor, terbufos + imazaquin, terbufos + imazaquin +

me tolachlor, and terbufos + imazaquin + metolachlor + CGA

- 154281 was

not enhanced compared to toxicity of each chemical (or combination of chemicals when applicable) alone. Toxicity to corn from exposure to terbufos + acetochlor was reduced compared to exposure to acetochlor alone (only at the 6.7 kg/ha acetochlor application rate). Toxicity of terbufos + primisulfuron was the same as that of primisulfuron alone for barnyard grass, giant foxtail, and velvetleaf.

### 75 Citation Chemicals tested 1 

### Test species Summary 3

Langton, 1997 Terbufos

, Flumetsulam,

Cl opyralid, 2,4

- D, Rimsulfuron, Thifensulfuron, Halosulfuron, Safener, Prosulfuron, Primisulfuron, and

Nicosulfuron Corn S ignificant interactions between terbufos and other chemicals were observed

in terms of effects on corn (height, yield, and stand) after exposure to mixtures of terbufos + flumetsulam, terbufos + nicosulfuron, terbufos + flumetsulam + nicosulfuron, terbufos + flumetsulam + nicosulfuron + pyrimisulfan, and terbufos + rimsulfuron + thifensulfuron . Terbufos did not show significant interactions in any other combinations of tested chemicals (terbufos + prosulfuron + primisulfuron, terbufos + halosulfuron + safener, terbufos + halosulfuron, and terbufos + flumetsulam + clopyralid + 2,4

- D )

.

Lentz et al.

, 19 8 5 Terbufos and

Metribuzin S o ybean Treatments of terbufos when combined with metribuzin produced significantly greater injury and reduced yield than when metribuzin or terbufos was applied alone.

Messaad et al.

, 2000 Terbufos and Atrazine Red s hiner minnow ( C. Lutrensis ) Generally, thermal tolerance of red shiner after exposure to atrazine, terbufos, or a mixture of both compounds decreased at both test
temperatures compared to the control. Thermal tolerance was measured as

the critical thermal maximum response method (CT M)

. There was a possible additive effect of the mixture observed at the highest test temperature/mixture concentration combination.
Messaad, 1996 Terbufos and Atrazine Red s hiner m innow ( C. Lutrensis ) Overall survival was lowest for the pesticide mixture (92% at 23 °C and 48%

at 30° C) in comparison to atrazine only at 30 ° C (54%), terbufos (97% at 23

° C and 91% at 30 ° C) or the control (100%).
Morton, 1993 Terbufos and

Nicosulfuron Field and sweet corn ( Zea mays ) Exposure to n icosulfuron and terbufos increased plant injury and tiller

formation and decreased yield and height compared to exposure to either compound alone. The toxicity of the mixture varied and was a function of many factors including application rate, application timing (nicosulfuron), terbufos formulation and method of application, effect endpoint, and experimental site location

. Toxicity of the mixture was not enhanced in all

cases.
Morton et al.

, 1994 Terbufos and

Nicosulfuron Corn ( Zea mays ) In two of three locations, vigor was reduced more when corn was exposed to

both nicosulfuron and terbufos compared to nicosulfuron or terbufos alone

. Similarly, grain yield was reduced more by the mixture in some of the experimental groups at one of the locations

. Noet zel and Kellesvig, 1993 Terbufos and

Carbofuran Canola ( Brassica

napus ) The combination of terbufos and carbofuran did not impact toxicity to canola compared to that of each chemical alone.

### 76 Citation Chemicals tested 1 

### Test species Summary 3

R ahman and James

, 1993 Terbufos and

Nicosulfuron Corn ( Zea mays ) D amag e to corn increased with increasing exposure to nicosulfuron and varied by terbufos application method; damage was greater when terbufos was applied in an open furrow or as a 17

- cm band with or without incorporation. Despite phytotoxic effects, all pl ants recovered within 4

weeks

. Exposure to terbufos and nicosulfuron had no effect on crop yield or crop maturity compared to exposure to nicosulfuron alone

. Simpson et al.

, 1994 Terbufos, Nicosulfuron, and 2,4

- D Corn ( Zea mays ) Exposure to n icosulfuron and terbufos caused increased visual injury and reduced dry weight

. Exposure to 2,4

- D and terbufos did not result in an

obvious increase in visual injury or reduce dry weight. Exposure to 2,4

- D,

nicosulfuron , and terbufos decreased the degree of visual injury and amount of reduction in dry weight caused by the nicosulfuron/terbufos interaction. The timing of the 2,4

- D application relative to the nicosulfuron application impacted the safening effect on the ni cosulfuron/terbufos interaction.

Smart and Bradford,

1995 Terbufos, Prosulfuron,

and Atrazine Corn and Sorghum The mixture of prosulfuron and terbufos increased effects on corn height, injury, and leaf stage but not yield. The mixture of atrazine and terbufos did not impact effects on corn. Irrigated sorghum yield was reduced by exposure to prosulfuron and terbufos but not to atrazine and terbufos compared to a no herbicide control. Irrigated sorghum height and leaf stage were also impacted by the prosulfuron and terbufos mixture.

Ti en and Chen, 2012 Terbufos, Chlorpyrifos, and Methamidophos Diatom ( Nitzschia sp.), cyanobacteria

Oscillatoria sp., and chlorophyta (Chlorella sp.) The EC 50 values for the pesticide mixtures (terbufos + chlorpyrifos, terbufos + methamidophos, and terbufos + chlorpyrifos + methamidophos) were mostly higher than those for single pesticide s (antagonistic effect)

. Only on e mixture (terbufos + methamidophos) showed a synergistic effect and that

effect was on a multiple algal species assemblage; in contrast this chemical mixture had an antagonistic effect on single species of algae.

Wal drop and Banks,

1983 Terbufos, Acifluorfen, Toxaphene, BAS

9052, Metribuzin, Metolachlor, and Oryzalin Soybean ( Glycine

max ) Ef fects from exposure to terbufos plus either acifluorfen, toxaphene, BAS

9052, or metolachlor were not significantly different from those due to exposure to the individual compounds. Exposure to terbufos plus either metribuzin or oryzalin caused increased toxicity (increased injury, decreased shoot and root weights, and/or decreased yield) compared to exposure to the individual compounds. Increased effects due to the mixture were observed for metribuzin in both greenhouse and field (2 years) experiments wh ereas they were observed for oryzalin in greenhouse but not field experiments.

1 The term “mixture” used in this table means that the test species was exposed at some po int during the experiment to terbufos and one or more other pesticides . It does not necessarily mean that the chemicals were applied simultaneously. For example, terbufos may have been applied to the soil fol lowed by a foliar application of an herbicide.

2 This review focuses on chemicals that were tested as mixtures with terbufos. In some cases additional chemicals were tested but not in combination with terbufos; these chemicals are not reported here.

3 The summary focus es on potential interactions between terbufos and other chemicals and is not intended to be a comprehensive detailin g of all results.

### 77 Appendix E : Incident Data

Table E

- 1 . Terbufos Aquatic Incidents (EIIS)

Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Unknown 1 2003 IN 50

- 60

300

- 400

Over 2000 Bass

Bluebird Crappie Probable

. The fish kill occurred on May 8, 2003 in a pond in Grant County, IN.

Terbufos ( Counter CR ) was thought to be involved

. It was reported that terbufos was present in the pond. It was also reported that a residue of 1.46 ppm was detected but the compound was not specified

. (I013987

- 001 )

Unknown 1 2003 IN 120

4400

6000 Bass Bluegill Crappie Possible. The fish kill occurred on April 22, 2003 in two pond s in Grant County, IN. The granular Counter CR formulation of terbufos had been applied a nearby field

. Terbufos and

its “ toxic degradates ” (undefined) were detected in both ponds at concentrations > 2 ppb. (I014116

- 001)

Corn 2000 IN 650

100

200

200 Bluegill

Bass

Catfish Crappie Highly Probable. The fish kill occurred from June 1 6, 2000 to June 17, 2000 in a pond adjacent to a corn agricultural area in Ohio County, IN. Terbufos (Counter) had been applied to a corn on a nearby field

. Terbufos sulfoxide (3.4

- 5.1 ppb) and terbufos sulfone (1.8

- 3.6 ppb) were detected in the pond 34 days after application to the field. The legality of the incident is misuse or accidental. (I010477

- 002)

Corn 2000 IN 4000

300

40

Few Bluegill

Bass

Catfish Crappie Highly Probable. The fish kill occurred on May 16, 2000 in a pond adjacent to a corn agricultural area in Montgomery County, IN. Terbufos (Counter) had been applied to a corn on a nearby field

. Terbufos sulfoxide (12

- 21 ppb) and terbufos sulfone ( 1.28 ppb) were detected in the pond 23 days after application to the field. The legality of the inc ident is

misuse or accidental. (I010477

- 001)

Corn 1998 NE 180

20 Bluegill

Catfish Highly Probable. The fish kill occurred in a 1 acre farm pond in Nebraska (location not given). Terbufos had been applied to a corn field 23 days earlier; there was a slope of 15% in the field. Terbufos was not detected in the water but 5 days after the incident the

con centration of terbufos sulfoxide was 15.5 ppb and terbufos sulfone was 6.6 ppb. (B0000

- 506

- 02)

Corn 1998 IN 300 Bluegill Highly Probable. The fish kill occurred in a pond in a field near Greensburg, IN. Terbufos was not detected in the water but water concentrations of 20.8 to 22.7 ppb of terbufos sulfoxide and sulfone were detected 2 days after the incident. Water concentrations of 1.2

- 1 .3 ppb of terbufos sulfoxide were detected 47 days after the incident. (B0000

- 506

- 01)

### 78 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1998 IN 10 000

3 000

100

200 Bluegill Largemouth

Bass

Catfish Walleye Possible. The fish kill occurred on June 19, 1998 in a 15 acre, 20 foot deep farm pond in Lagro, IN. The grower applied the CR formulation of terbufos as a T

- band application at planting at the rate of 1.3 lb ai/A to a 75 acre corn field. The "field drains into neighbor's farm pond and pond overflows into reported pond incident". Analysis of water samples

revealed no evidence of terbufos residues. ( I 007795

- 0021)

Corn 1998 IN 2000

- 3000

500 Bluegill Largemouth

Bass Possible. The fish kill occurred on June 19, 1998 in a farm pond in Lagro, IN. The grower applied the 20C R formulation of terbufos as a T

- band application at planting at the rate of

1.3 lb ai/A to a 75 acre corn field. The field drains via tile into the farm pond. There is also a 2 to 3 foot deep drainage ditch that carries runoff into the pond. Analysis of wat er samples

revealed no evidence of terbufos residues. ( I 007795

- 001)

Corn 1 1998 IN 2400

20

10

1 Bluegill

Bass Frog Carp Probable. The fish kill occurred on June 18, 1998 in a farm pond in Huntington, IN. The grower applied the 20CR formulation of terbufos as a T

- band application at planting at the

rate of 1.3 lb ai/ A to a 46 acre field. Analysis of water samples revealed terbufos sulfoxide and terbufos sulfone residues. ( I 007676

- 001)

Corn 1 1998 IN >5000 Bluegill

Bass

Catfish

Minnow Crappie Probable. The fish kill occurred on June 13, 1998 in a 2 acre farm pond in LaFountaine, IN. The grower applied the 20CR formulation of terbufos as a T

- band application at planting at the rate of 1.3 lb ai/A to a 76 acre field. Analysis of water samples revealed

terb ufos sulfoxide and terbufos sulfone residues. ( I 007924

- 006 ; I007513

- 006 )

Corn 1 1998 IN 1400 Fish Probable. The fish kill occurred on June 13, 1998 in 2 farm ponds in Lewis, IN. The grower applied the 20CR formulation of terbufos as a T

- banded application at planting at the labeled rate. Analysis of water samples revealed terbufos sulfoxide and terbufos sulfone residues. ( I 007924

- 005 ; I007513

- 005 )

Corn 1 1998 IN ~1100

50

- 75

200 Bluegill

Bass Crappie Probable. The fish kill occurred on June 14 , 1998 in a 3 acre farm pond in Wabash, IN. The grower applied the 20CR formulation of terbufos as a T

- band application at planting at the rate of 1.3 lb ai/A. Mortality estimates for bluegill ranged from 1000

- 1200. Analysis of water samples revealed terbufos s ulfoxide and terbufos sulfone residues. ( I 007924

- 004 ; I007513

- 004 )

### 79 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1 1998 IN 1000

100

50 Bluegill

Bass Walleye Probable. The fish kill occurred on June 16, 1998 in a 2 acre farm pond in Wabash County, IN. The grower applied the CR formulation of terbufos as a T

- band application at planting. Analysis of water samples revealed terbufos sulfoxide and terbufos sulfone

residues. ( I 007924

- 003 ; I007513

- 003 )

Corn 1 1998 IN 51 00

100 Bluegill

Bass Probable. The fish kill occurred on June 13, 1998 in 2 farm ponds in Chester, IN. The grower applied the CR formulation of terbufos as an in

- furrow application at planting at

the rate of 1.3 lb ai/A to a 38.5 acre field. Analysis of water samples revealed terbufos

sulfoxide and terbufos sulfone residues. ( I 007924

- 002 ; I007513

- 002 )

Corn 1 1998 IN 60

32

1 Bluegill

Bass

Catfish Probable. The fish kill occurred on June 16, 1998 in a 0.8 acre farm pond in Wabash, IN. The grower applied the CR formulation of terbufos as a T

- band application at planting at

the rate of 1.3 lb ai/A to a 74 acre field. Analysis of water samples revealed terbufos

sulfoxide and terbufos sulfone residues. ( I 007924

- 001 ; I007513

- 001 )

Banana plantation 1997 Philippin es NR Fish Probable. The fish kill occurred on January 1, 1997 on agricultural land in the Philippines

. Mortality may be linked to runoff of multiple pesticides, including the granular form of

Counter 10G. (I006395

- 001)

Corn 1 1997 Corn belt NR Fish Possible. American Cyanamide reported 5 fish kill incidents involving farm ponds in Indiana, Nebraska, and possibly other corn belt states in 1997. (I006718

- 001)

Corn 1 1996 Corn belt NR Fish Possible. American Cyanamide reported 1 fish kill incident in the corn belt in 1996

. (I004607

- 001; I006718

- 001)

Corn 1 1995 Corn belt NR Fish Possible. American Cyanamide reported 4 fish kill incidents involving farm ponds in the corn belt in 1995 (I002814

- 001 ; I006718

- 001)

Corn 1 1994 Corn belt NR Fish Possible. American Cyanamide reported 7 fish kill incidents involving farm ponds in the corn belt in 1994 (I002814

- 001 ; I006718

- 001)

Corn 1994 NC 100 Bass Bluegill Crappie Probable. On May 10, 1994, the North Carolina Department of Agriculture reported a fish kill incident involving approximately 100 fish that occurred in a canal that fed into the Pasquotank River in Pasquotank County. Terbufos (Counter CR ) had been applied to a

corn field adjacent to the canal. Residue analysis revealed 140 ppb of terbufos in the canal. ( I 003826

- 025; IR94

- 51; North Carolina Department of Agriculture)

### 80 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1994 LA 1386 Fish Probable. Terbufos and permethrin applied preplant to 3769 acres of corn. The Louisiana State University Medical Diagnostic Laboratory concluded that the fish were killed by terbufos and permethrin. ( I 001849

- 003 ; I 001179

- 20)

Corn 1 1993 Corn belt NR Fish Possible. American Cyanamide reported fish kill incidents at 14 farm ponds in the corn belt

in 1993

. ( I 002814

- 001 ; I 006718

- 001)

Corn 1993 NC 15

15 Bass

Bream Highly Probable. A fish kill occurred in Clinton, NC (Sampson County) on April 6 following application of atrazine and terbufos to a neighboring corn field approximately 365 feet away. Water samples taken a week later revealed 2 ppb of terbufos. No analyses were conducted on the dead fish. ( I 003654

- 003)

Corn 1 1992 Corn belt NR Fish Possible

. American Cyanamide reported 2 fish kill incidents in the corn belt in 1992
( I 002814

- 001 ; I 006718

- 001)

Corn

tobacco 1992 NC Small

number Bluegill Possible. A fish kill in a small pond adjacent to tobacco and corn fields in North Carolina on June 12, 1992. Terbufos, carbofuran, and aldicarb were applied to adjacent fields

. ( I 000165

- 052)

Banana 1992 Costa Rica 1250

300 Fish Tilapia Probable. Moribund fish were discovered in a river adjacent to a terbufos

- treated banana farm. Other pesticides had also been used in the area. According to the report terbufos was suspected as being responsible for the fish kill. (I000286

- 001)

Corn 1 1991 IA NR F ish Probable/Misuse

. Grower in Fontanelle, Adair County, I A, reportedly left a partially used bag of Counter® 15G eight feet from pond. (B 000 170

- 6; I 002814

- 002)

Corn 1991 IA 4 000

- 5 000 Bluegill Crappie

Small Bass Probable. This incident involved 6 ponds in Chariton, Lucas County, I A. Residue analysis

2 to 4 weeks after treatment showed 1

- 4 ppb terbufos sulfoxide in the pond. (B 000 170

- 4 ;
I 002814

- 002)

Corn 1991 IA large

number Bluegill

Bass Crappie

Catfish Probable. Fish kill occurred on June 9 in several ponds east of Chariton, I A. The largest pond (3.5 acres) was surrounded by 300

- 1000 feet of pasture/grassy buffer strip. Terbufos was applied as a banded application on an adjacent farm. Terbufos residues (1 ppb) recovered from pond water on July 6. No analyses made on dead fish. (B000300

- 41)

### 81 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1991 IA 500

400

3 Bluegill

Bass Snapping

Turtle Probable. Fish kill occurred in 2 ponds in Milo, Warren County, I A. Incident is related to a study by Wildlife International. Pond was surrounded by grassy strips and steep sloped

corn fields. Terbufos also caused a fi sh kill in these ponds in 1990. (B 0 0 0 170

- 005 ;
I 0 02814

- 002)

Corn 1991 IA NR Fish Possible

. A p ond near corn field in Lucas County, IA experienced a fish kill in June, 1991. No residue analysis was performed. (I000254

- 002: Submitted by Region VII )

Corn 1991 IA NR Bluegill

Bass Crappie

Catfish Highly Probable. Pond near corn field in Lucas County, I A experienced fish kill in June, 1991. Residue analysis revealed terbufos in water following kill and 3 weeks later.

Triflu ralin and Bicep also applied. (I000254

- 001: Submitted by Region VII)

Corn 1991 IL 1 000 Bluegill Probable. Pond in Nashville, Washington County, IL experienced a fish kill. An assay conducted 2 weeks after treatment revealed 3 ppb terbufos sulfoxide

. (I002814

- 002;

I 000 170

- 001)

Corn 1991 IL 41 800

38 000

6 318

4 343 Bluegill

Bass

Sunfish Crappie Highly Probable. On May 4, 1991, terbufos was applied at a rate of 1.3 lb ai/A on a no

- till corn field adjacent to Taylor Lake, in Victoria, IL (Knox County). Taylor Lake is a former strip mine. A total of 90,461 fish were found dead. The species affected included bluegill, largemouth bass, green sunfish, black crappie, red

- ear sunfish, and hybrid sunfish. The dead sunfish had the pectoral fin in the forward position across the head: which is considered to be a sign of OP toxicosis. An assay conducted 2 weeks after treatment

reveale d 2 to 9 ppb terbufos sulfoxide . (I005002

- 003; B000 166

- 001; I002814

- 002;

I 000 170

- 2; Illinois Department of Conservation,1991)

Corn 1991 IN 1 500 Bluegill Crappie Possible. Incident occurred in Whiteland, Brown County, IN involving 1500 bluegill and crappie fingerlings. No assay was conducted. (I002814

- 002; I000170

- 003)

### 82 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn

T obacco 1991 NC 200+ Bluegill

Bass Possible. On May 10, 1991, a fish kill occurred in Onslow, North Carolina

. Terbufos, disulfoton, ethoprop, chlorpyrifos, atrazine, and napropamide were applied to adjacent corn and tobacco fields. Analysis of pond water and surrounding soils found terbufos, chlorpyrifos, napropamide, and atrazine residues. Because the chlorpyr ifos and terbufos

residu es were higher than napropamide and atrazine residues, they were considered more likely to have caused the kill. The crops that were associated with the fish kill were corn and tobacco. Terbufos was applied to the corn crop only. A corrugated pipe connects the fields to a drainage ditch and a concrete pipe to connect the ditch and runs under the road to the pond. Apparently pesticide application was applied too close to the water. (I000799

- 004; IR91

- 60 North Carolina Department o f Culture)

Corn or

S orghum 1991 TX NR F ish Possible. Incident occurred on April 19, 1991 in a lake adjacent to a 500 acre treated field in Lamar, Texas. Assay of water samples was negative. Crop listed in report as field crop/grain with the pest as greenbug. ( I 00917

- 004· TDA incident No. 11

- 91

- 0017)

Corn 1990 IA 300 Bluegill Probable. Event occurred in Audubon County, IA. Terbufos sulfoxide found in residue analysis. (B 000 168

- 002 ; I002814

- 003)

Corn 1990 IA 200 Bluegill Probable. Event occurred in Audubon County, IA. Terbufos sulfoxide found in residue analysis. (B0 0 0168

- 001 ; I002814

- 003)

Corn 1990 IA 200+ Bluegill Probable. Event occurred in Montgomery County, IA. Field sloping towards pond. Terbufos sulfoxide found in residue analysis. (B0 0 0168

- 003 ; I002814

- 003)

Corn 1990 IA 200+ Bluegill Probable. Event occurred in Warren County, I A. Terbufos sulfoxide found in residue analysis. (B 0 0 0 168

- 006 ; I002814

- 003)

Corn 1990 IA 200+ Bluegill Probable. Event occurred in Milo, Warren County, IA. Incident is related to a study by Wildlife International. Terbufos sulfoxide found in residue analysis. (B0 0 0168

- 005)

Corn 1990 IA 500 Bluegill Possible. Event occurred in Washington County, I A. No residue samples taken

. (B000168

- 004 ; I002814

- 003)

Corn 1990 IA 200+ Bluegill Probable. Event occurred in Warren County, IA. Terbufos sulfoxide found in residue analysis. (B00 0 168

- 006 ; I002814

- 003)

### 83 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1990 IL 150 Bluegill Possible. Event occurred in Coles County, IL. No residue samples taken

. (B000168

- 013 ; I002814

- 003)

Corn 1990 IL 10 000

- 15 000 Fish Possible

. Event occurred in McHenry County, IL. No residue samples taken

. (B000168

- 014)

Corn 1990 IL NR Bluegill Probable. Event occurred in Du Page County, IL. Terbufos found in residue analysis. (B0 0 0168

- 015)

Corn 1990 IL 20 Bluegill Probable. Event occurred in St Clair County, IL. Terbufos sulfoxide found in residue analysis. (B 0 0 0 168

- 0016)

Corn 1990 KS 300 Fish Probable. Event occurred in Leavenworth County, KS. Terbufos was applied in

furrow. Terbufos sulfoxide found in residue analysis. ( B0 0 0168

- 007 )

Corn 1990 MI 500

- 600 Bluegill Probable. Event occurred in Hillsdale County, MI. Terbufos was applied as a banded application. Terbufos sulfoxide found in residue analysis. (B 0 00168

- 008)

Corn 1990 OH 100 % in

4

- 5 acre pond Bass, Bluegill

Catfish Crappie

Snake Probable. On May 15, 1990, bass, bluegill, catfish, crappie, and a black snake were reported killed from the use of terbufos applied in

- furrow at

- planting on a corn field at a rate of 1.3 lb ai/A in Licking County, Ohio. The Ohio Department of Agriculture measured

t erbufos residues of 10 ppb. Ammonia, atrazine, and metolachlor residues were also found. The investigator concluded that the kill could have been caused by terbufos or ammonia. The total kill was reported for the 4 to 5

- acre pond that was 5 to 6 feet deep (B000168

- 12; 4220 59

- 01; American Cyanamid, 1992)

Corn 1990 OH NR Bluegill Probable. Event occurred in Clinton County, OH. Terbufos was applied as a banded application. Terbufos sulfoxide found in residue analysis. (B0 0 0168

- 010)

Corn 1990 OH 1 500

- 1 800 Bluegill Possible. Event occurred in Darke County, OH. Terbufos was applied as a banded application. There was no residue analysis performed. (B 0 0 0 168

- 011)

Corn 1990 OH 10 000

- 15 000 Bluegill Probable. Event occurred in Licking County, OH. Terbufos was applied as an in furrow application. Terbufos sulfoxide found in residue analysis. (B 0 0 0 168

- 009)

### 84 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1

S orghum 1 1990 TX 200 Fish Probable. Incident occurred in Bell County, Texas. Investigators suspect that runoff from the neighbors field into tank caused the fish to die. Samples of fish analyzed contained terbufos. Crop listed in report as field crop/grain. Corn and sorghum are the

most li kely crops to have been involved. Metalochlor , 2,4

- D, atrazine, and picloram were also applied to adjacent fields. (I00917

- 003; TDA incident No. 05

- 90

- 0034)

Corn 1989 NC 600

12 Small Fish Crayfish Highly probable. On May 5, 1989, a fish kill occurred from the use of Counter 15G on a nearby corn field in Sampson County, NC. About 600 small fish and 12 crayfish were found dead in an adjacent water body. The corn field was treated on April 20. The

metabolite of terb ufos, terbufos sulfone, was detected in the water samples

. (B 000 169

- 001; IR89

- 40. North Carolina Department of Agriculture 1989)

Corn 1989 NC 2000+ Fish Highly probable. On April 30, 1989, thousands of fish were killed in a canal which

feeds into the Alligator River following the application of terbufos 15G and alachlor to corn in Tyrell County, NC. By the time the fish kill was investigated on May 1, 1989, the fish had drifted into the Alligator River. Terbufos had been applied in

- furrow at

planting and alachlor on top after planting. Terbufos sulfone, the metabolite of terbufos, was detected in soil samples

. (B000164

- 001; R89

- 37. North Carolina D epartment of Agriculture, 1989)

Corn 1989 NC 400 Fish Highly probable. On May 16, 1989, about 400 fish died from the use of Counter 15G. Terbufos was measured in the water samples taken in a pond adjacent to a field that was treated with terbufos on corn. An adjacent tobacco field had been treated with ethoprop and pebulate, but no measurable residues wer e detected for those chemicals

. (B 000 167

- 001; IR89

- 44. North Carolina Department of Agriculture, 1989)

Corn 1985 NE 1000 Fish Possible. Terbufos was applied in a corn field in Butler County, NE on May 8, 1985. The water source for this pond was filtered overflow from a larger pond which had also suffered a fish kill at the same time. Terbufos (applied in

- furrow to corn) and phorate (applied to sorghum) had recently been used in nearby fields above the pond. (I000598

- 001A;

Nebraska Game and Parks Commiss ion, 1985).

Corn 1 1985 NE "many" Fish Possible. In 1985, terbufos was applied in a field near a pond in Richardson County, NE. (I000598

- 007

, Nebr aska Game and Parks Commission)

### 85 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1984 SC 100

100 Bass

Bream Possible. On April 2, 1984 a fish kill was reported in Williamsburg County, SC. Terbufos, atrazine, and metalochlor were used on the adjacent corn field 2 to 3 days before the kill. Analysis of a water sample showed no terbufos residues but tested positive

for atrazine and metalochlor. (B000163

- 001)

Corn 1981 MO NR Fish Possible. Fish kill occurred on May 29, 1981 in Krueger Pond, Lafayette County, MO (near the town of Alma). A one acre pond was affected. Butylate and atrazine were also applied to the corn field

. (B000165

- 001; I000636

- 032)

Corn 1981 MO NR Bluegill Crappie Possible. On June 3, 1981, terbufos was implicated in a Missouri fish kill with multiple pesticide use (atrazine, Sutan and terbufos). Many small bluegill and a few crappie reportedly were affected from the use on corn

. (Missouri De partment of Conservation, 1981)

Corn 1978 I A many F ish Possible. Terbufos was applied in a corn field in Iowa in 1978. Runoff into a farm pond drained about 1⁄2 acre of the treated corn field. Many dead fish were found in the pond

. (Pesticide I ncident Monitoring System, 1981)

Unknown 1 1976 IL 20 Bluegill Possible. Around April 1976, terbufos was applied to a field across the road from a 0.8 acre pond in Illinois. About 20 dead bluegill were found. Laboratory work did not confirm the presence of terbufos

. (Pesticide In cident Monitoring System, 1981)

1 Crop association

, if any

, is uncertain.
*Some incidents were linked to specific formulations (Counter 15G and CR)

. The Counter 20G formulation was not specifically linked to any incidents

. NR = n ot reported

NOTE: hundreds interpreted as 200+ ; thousands as 2,000+ soil incorporated interpreted as in

- furrow application surface application interpreted as banded application

### 86 Table E

- 2 . Terbufos Terrestrial Incidents (EIIS database)

Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Unknown 1 2008 KS 1

87

55

47 Mallard

White

- fronted goose

Canada goose Goose Possible. Incident occurred in Rice, KS starting on December 16, 2008 and ending on December 23, 2008. This mortality was out of approximately 10,000 geese that were using the 20

- acre refuge area on private ground. Two Canada geese, two Cackling geese, one White

- fronted goose, and one Mallard were analyzed. Salt toxicosis was determined to be the cause of death in one Canada goose, one Cackling goose, and one

White

- fronted goose. Terbufos was detected in the gizzard content of one of th e White

- fronted geese. Strychnine was detected in a Mallard duck. (I020995

- 002)

Unknown 1 2002 NC 5 Red wolf Possible. Incident occurred in Hyde, NC starting on March 9, 2002 and ending on March 14, 2002. Cause was diagnosed as toxicosis by terbufos plus scabies infection. (I018980

- 007)

Unknown 1 2001 NJ 1 Cooper’s Hawk Highly Probable. Incident occurred in Burlington County, NJ on May 2, 2001. A necropsy showed that its brain cholinesterase activity was reduced 78% below normal,

and the stomach contents (bird remains and two wheat seeds) had 61.8 ppm terbufos. The conclusion was that terbufos was the cause of death, but there was no

determination of the source of the terbufos. (I012549

- 007)

Corn 1997 DE 2 Canada geese Highly Probable. Incident occurred in Felton, DE (Kent County) on May 27, 1997 in a 7 acre stand of field corn. The geese were feeding in the newly planted corn which had been treated with Counter 15G. There were heavy rains prior to the incident. Analysis of the stoma ch contents revealed 75 ppm of t erbufos

. (I007372

- 001)

M isuse 1996 C anada NR Eagles Probable/Misuse. Carcasses baited with t erbufos for coyote control in Saskatoon area

of Canada

. (I004605

- 00 1; references newspaper article in Star Phoenix)

### 87 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

Corn 1996 TX 20 Swainsons hawks Highly Probable/Misapplication . An incident in occurred on April 27, 1996 near Dumas, Texas (King County) in which about 20 migrating Swainson's hawks were killed by t erbufos (Counter 15G). The registrant commissioned a team of scientist s to conduct an assessment of the incident. The unpublished report developed by that team has been reviewed by the Agency. The report draws the following conclusions: The hawks were killed while gorging on grubs (larvae of the Southern masked chafer) ex posed in a newly plowed field. Stomach contents were found to contain soil, grubs, and t erbufos residues ranging from 6.5 to 16 ppm. The exposure of the

birds to t erbufos resulted from failure to cover the furrows after plowing. The furrows were not pro perly covered because of equipment failure associated with plowing under unusually wet soil conditions. In much of the field, the corn seed and

the t erbufos granules were deposited on to the soil surface instead of inside the

furrow. The dead hawks were discovered 7 days after planting. The conclusion of the report is that the incident occurred under an unusual set of condi tions. (I003498

- 001; I006435C)

Corn 1 1995 WI 2 Red

- tailed hawk Highly Probable . An adult female and a hatchling red

- tailed hawk were found at the base of a tree in Madison, WI. Meat taken from the crops of the hawks contained 12 and 13 ppm t erbufos. The investigator speculated that the prey of the hawks had

been a rodent from a nearby corn field. (I002993

- 012 ; I002733

- 043, USFWS case

file 2300 )

Unknown 1 1994 Canada 4 Bald eagles Highly Probable/Possible Misuse . An incident occurred in Vancouver, British Columbia involving 4 eagles. Analysis of the contents of the crop and stomach confirmed the presence of t erbufos and its oxidative degradates at levels that could have caused the death of the eagles. Misuse is suspected b ecause the eagles were found many months after the normal application time for terbufos and the significant

amounts of t erbufos (relative to the amounts of oxidative degradates)

. ( I002486)

Unknown 1 1994 NC 2 Red wolf Highly Probable/Misuse . Two dead red wolves were found near a farm in NC in the Fall of 1994. Analysis of the stomach contents revealed “large quantities” of

t erbufos (38 ppm), rabbit flesh, and shotgun pellets. The presence of these 3 items in the gut strongly supported a ca se of intentional poisoning. The wolves had been introduced by the U.S. Fish and Wildlife Service against the wishes of the owners

of the farm

. (I 002484)

### 88 Crop /

Source Year State Number

Affected Species

Affected Certainty Index, Summary of Incident ( Reference )

S ugarbeet 1 1992 OR 5

- 10 Bald eagles Highly Probable/Possible Misuse . Five bald eagle carcasses were collected in March, 1992 near Toulee Lake in the Klamath Basin Game Preserve, north of Klamath Falls OR. Analysis of the gut contents revealed t erb ufos residues. The gut content was mainly waterfowl. The source of the t erbufos was not known. The report noted that sugar beet are grown in the Klamath Falls area and t erbu fos is registered on sugar beet

. Ingestion of t erbufos laced bovine meat as a poison bait was also speculated since the

incident occu rred prior to plan ting of sugar beet and the registrant does not have any records of sale in this area. (I000089

- 001 ; B0000

- 300

- 39

, Bennett and Williams, 1996)

1 Crop association if any is uncertain.

### 89 Table E

- 3. Summary of Aggregate Incident Data for Terbufos

NOTE: Incidents in the Aggregate Incident Database may duplicate reports in EIIS or AIMS. Package and Sequence # Incident From Date Product Regulation # Product Name Formulation Sum Wildlife

Minor Plant Damage

Minor Other Non

Target

013492

- 00007 7/1/02

- 10/1/02 000241

- 00238 Counter 15G Granular 1 0 1 0

013492

- 00006 7/1/02

- 10/1/02 000241

- 00314 Counter CR Granular 4 0 4 0

012391

- 00006 7/1/01

- 10/31/01 000241

- 00314 Counter CR Granular 1 0 1 0

010544

- 00007 5/1/00

- 7/31/00 000241

- 00314 Counter CR Granular 1 1 0 0

010260

- 00001 6/1/00

- 6/30/00 000241

- 00238 Counter 15G systemic insecticide

nematicide Granular 1 1 0 0

010135

- 00001 1/1/00

- 4/30/00 000241

- 00238 Counter 15G systemic insecticide

nematicide Granular 3 3 0 0

008281

- 00006 9/1/98

- 11/30/98 000241

- 00241 Counter technical poison soil

insecticide Technical

Chemical 1 1 0 0

008063

- 00002 7/1/98

- 9/30/98 000241

- 00314 Counter XL systemic insecticide

nematicide Granular 1 1 0 0

007883

- 00001 6/1/98

- 8/31/98 000241

- 00314 Counter XL systemic insecticide

nematicide Granular 1 1 0 0

### 90 Table E

- 4 . Terbufos Incidents Identified in the Avian In cident Monitoring System (AIMS) 1

Species Pesticide(s) Location Year Source(s) Bald Eagle Terbufos Lancaster, NE 2002 FWSLE: Case 02

- 0330 FWSLE (INV): 2002602946 Green Jay Turkey Vulture Terbufos Nueces, TX 2001 FWSLE: Case 01

- 0268 FWSLE (INV): 2001201753 Cooper’s Hawk Terbufos Burlington, NJ 2001 EIIS: I012549

- 007 European Starling, House Sparrow Terbufos Gratiot, MI 2000 MAHDL: 2226138

MIWDL: 000098

MIWDL: 000099

MIWDL: 000100

MIWDL: 000101

MIWDL: 000102

MIWDL: 000103

MIWDL: 000104

Canada G ee se Terbufos Kent, DE 1997 EIIS: I007372

- 001 Eagle Terbufos Canada 1996 EIIS: I004605

- 001

Swainson’s Hawk Terbufos King, TX 1996 EIIS: I003498

- 001 Bald Eagle Terbufos Pender, NC 1996 FWSLE: Case 96

- 0460 FWSLE (INV): 605000193

Red

- tailed Hawk Terbufos Dane, WI 1995 EIIS: I002993

- 012

WAHL: 516215

WIDNR: 95

- 54

Passerine Terbufos Bonneville, ID 1994 FWSLE: Case 94

- 0490 FWSLE (INV): 1375AQ Bald Eagle Terbufos Nuckolls, NE 1993 CWS: CWS93

- 8

FWSW: 11500

- 001 Bald Eagle Terbufos Nuckolls, NE 1993 CWS: CWS93

- 7

FWSW: 11497

- 002 Bald Eagle Terbufos Klamath, OR 1992 EIIS: B0000

- 300

- 39 ; I000089

- 001

NOTE: Incidents with an EIIS number are also listed above in Table E

- 2

. 1 Two incidents in the AIMS database associated with terbufos are also reported in the EIIS database and are considered to have been caused by other pesticides; therefore, they are no t reported in Table E

- 4 . An incident from 1998 is associated with phorate (EIIS: I002486

- 001) and another is from 1992 and is associated with carbofuran

. (EIIS: I000799

- 007 and NC: IR92

- 72)

### 91 Appendix F : SWCC Input Parameters and Representative Sample Outputs

Table F

- 1

. SWCC Input Parameters for Terbufos

Parameter Input Value Source Comment

Application Rate Corn: 1.30 lb a.i/A Sorghum: 1.68 lb ai/A Sugar beet: 1.98 lb a.i/A

Corn: 2.6 lb a.i/A EPA Reg# 241

- 314

EPA Reg# 5481

- 562

EPA Reg# SLN No.

NC920001 Maximum application rates for specified crops based on

the labels

Number of application/year 1 EPA Reg# 241

- 314

EPA Reg# 5481

- 562 Label directions

Application method Incorporated Current Labels Label directions and to

simulate subsurface incorporation of applied

terbufos.

Depth of Incorporation 1 inch Current labels Label direction for corn.

For sorghum and sugar beet, incorporation depths

were assumed based on seeding depths

Use Site Scenario Corn

CA corn OP

IA corn STD

IL corn STD

IN corn STD

KS corn STD

MN corn STD

MS corn STD

NC CornE STD

NC CornW OP

ND Corn OP

NE corn STD

OH corn STD

PA corn STD

TX corn OP

FL sweetcorn OP

OR Sweetcorn OP Suger beet CA Sugar Beet Wirrg OP MN Sugar Beet STD Sorghum KS Sorghu m STD TX Sorghum OP Label directions

and available

scenarios The following scenarios were used in generating

EECs:

Corn 10 standard and 5 organo

phosphate specific

scenarios

Suger beet 1 standard and 1 organo

phosphate specific scenario

Sorghum

1 standard and 1 organo

phosphate specific scenario

Application Date Relative date: 7 days prior to emergence date in crop

scenarios Label Directions

---

Spray drift fraction Not applicable EFED Guidance (USEPA, 2013) ---

Molecular weight 288.4 g/mole MRID 4104495 02

---

### 92 Parameter Input Value Source Comment

Solubility in water (25 °C) 5.4 mg/L MRID 4104495 02

---

Vapor pressure 3.16E

- 04 (mmHg @25°C) MRID 4104495 02

--- Henry’s Law constant (20 °C) 2.46E

- 05 atm.m 3 /mol Footprint

Hydrolysis (t 1/2 ) 1 1.5 days @ 25°C @ pH 7 MRID 44862501

---

Aquatic photolysis (t 1/2 ) 1 1.77 days MRID 00161567 and

41181101 ---

Aerobic soil metabolism (t 1/2 ) 1 14.7 days MRID 00156853 and

41749801 Based on 90% of the upper confidence limit (UCL) of

the mean metabolism half

life (USEPA, 2009). Aerobic aquatic metabolism (t 1/2 ) 1 37.5 days MRID 44672004

Anaerobic aquatic metabolism (t 1/2 ) Stable

--- Since terbufos is sensitive to hydrolytic degradation, anaerobic aerobic aquatic

metabolism was assumed stable according to the Input Parameter Guidance (USEPA, 2009).

Partition coefficient K d 11.11 mL/g MRID 41373604 Mean K d for 4 soils

1 DT 50s were recalculated using NAFTA Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media (USEPA, 2012a). Appendix A contains revised estimated half

- lives.



### Table F

- 2

. SWCC Input Parameters for Terbufos Sulfoxide

Parameter Input Value Source Comment

Use Site and Scenarios

Application Dates See Table 5

Relative Date: 30 days after terbufos application Table 5 Application dates were adjusted based on

maximum terbufos

sulfoxide formation in laboratory studies.

Application Rate Corn: 0.72 lb Corn: 1.44 lb (NC SLN 920001) Sorghum: 0.94 lb Sugar beet: 1.05 lb Estimated See sample calculations

below 1

Number of applications

per year 1 EPA Reg# 241

- 314

EPA Reg# 5481

- 562 ---

Application method Ground

--- Degradation product of

terbufos Spray drift fraction Not applicable

---
Molecular weight 304.42 g/mole EPISUITE 4.1

---

Solubility in water (25 °C) 3214 mg/L MRID 44672001

and 44672002 Solubility of terbufos sulfoxide is higher than that

of terbufos.

Vapor pressure 3.42E

- 05 (mmHg @25°C) EPISUITE 4.1

### 93 Parameter Input Value Source Comment

Henry’s Law constant (25 °C) 9.13E

- 08 atm.m 3 /mol EPISUITE 4.1 Estimated using EPISUITE

model

Hydrolysis (t 1/2 ) 65.1 days @ 25°C MRID 44862501

---

Aquatic photolysis (t 1/2 ) Stable

--- In absence of data, assumed stable according to the Input Parameter Guidance (USEPA, 2009)

Aerobic soil metabolism (t 1/2 ) 136 x 3 (408 days) MRID 00156853 Single value is available. 3X was used according to the Input Parameter Guidance (USEPA, 2009)

Aerobic aquatic metabolism (t 1/2 ) Stable

--- In absence of data, assumed

stable

Anaerobic aquatic metabolism (t 1/2 ) Stable

--- Since terbufos sulfoxide is sensitive to hydrolytic degradation, anaerobic aerobic aquatic metabolism

was assumed stable according to the Input

Parameter Guidance (USEPA, 2009)

Partition coefficient K d 1.12 mL/g MRID 41373604 Mean K d for 4 soils

1 Terbufos s ulfoxide application rate = terbufos application rate of 1.30 lb x (0.523, the maximum conversion rate from the degradation of terbufos to terbufos sulfoxide in laboratory studies) x (1.055, the molecular weight ratio

of terbufos sulfoxide to te rbufos

.



### Table F

- 3

. SWCC Input Parameters for Terbufos Sulfone

Parameter Input Value Source Comment

Use Site and Scenarios

Application Dates See Table 5

Relative Date: 60 days after terbufos application Table 5 Application dates were adjusted based on maximum

terbufos sulfone formation in the laboratory studies.

Application Rate Corn: 0.29 lb Corn: 0.58 lb (NC SLN 920001) Sorghum: 0.38 lb Sugar beet: 0.44 lb Estimated See a sample calculations

below 1

Number of applications

per year 1 EPA Reg # 241

- 314

EPA Reg# 5481

- 562

Application method Ground

--- Degradation product of

terbufos Spray drift fraction Not applicable

--- Molecular weight 320.42 g/mole EPISUITE 4.1

---

Solubility in water (25 °C) 407 mg/L MRID 44672001

and 44672002 Terbufos sulfon e is more

soluble than terbufos

Vapor pressure 7.88E

- 06 (mmHg @25°C) EPISUITE 4.1 Estimated using EPISUITE

model Henry’s Law constant (25 °C) 4.10E

- 08 atm.m 3 /mol EPISUITE 4.1

### 94 Parameter Input Value Source Comment

Hydrolysis (t 1/2 ) 43.8 days @ 25°C MRID 44862501

--- Aquatic photolysis (t 1/2 ) Stable

--- Assumed stable

Aerobic soil metabolism (t 1/2 ) 174 x 3 (522 days) MRID 00156853 Single value is available. 3X was used according to the Input Parameter Guidance (USEPA, 2009)

Aerobic aquatic metabolism (t 1/2 ) Stable ---- In absence of data, assumed

stable according to the Input

Parameter Guidance (USEPA, 2009)

Anaerobic aquatic metabolism (t 1/2 ) Stable

--- Since terbufos sulfoxide is sensitive to hydrolytic degradation, anaerobic aerobic aquatic metabolism

is assumed sta ble according to the Input Parameter Guidance (USEPA, 2009)

Partition coefficient K d 1.26 mL/g MRID 41373604 Mean K d for 4 soils

1 Terbufos sulfone application rate = terbufos application rate of 1.30 lb x (0.201, the maximum conversion rate

from the degradation of terbufos to terbufos sulfone in laboratory studies) x (1.11, the molecular weight ratio of

terbufos sulfo ne to terbufos

.



### Table F

- 4. SWCC EECs for Terbufos, Terbufos Sulfoxide and Terbufos Sulfone for Various Crop Scenarios and Application R ates

Surface Water Pore Water

Scenarios Peak 4

- day 21

- day 60

- day 90

- day Peak 21

- day

Concentration (μg/L)
Terbufos (Corn/Sweetcorn)

IAcornstd 7.06 2.81 0.63 0.23 0.16 5.14 3.88

ILCornSTD 7.79 3.07 0.95 0.35 0.23 3.88 3.23

INCornStd 7.44 3.25 0.93 0.34 0.23 1.83 1.47

KSCornStd 8.98 3.92 1.27 0.46 0.31 1.96 1.59

MNCornStd 5.87 2.28 0.49 0.18 0.12 1.36 1.09

MScornSTD 17.30 8.92 2.44 0.90 0.60 11.30 8.74

NCcornESTD 4.76 2.34 0.54 0.19 0.13 1.29 1.04

NECornStd 11.90 5.39 1.45 0.57 0.38 3.85 3.15

OHCornSTD 9.31 4.21 1.00 0.41 0.28 6.58 5.03

PAcornSTD 3.29 1.36 0.41 0.15 0.10 0.77 0.62

CAcornOP 1.71 0.68 0.15 0.05 0.04 0.52 0.41

FLsweetcornOP 11.50 4.22 1.03 0.47 0.69 0.46 0.38

NCcornWOP 3.86 1.65 0.40 0.16 0.11 0.42 0.35

NDcornOP 1.50 0.76 0.18 0.07 0.05 0.21 0.17

ORswcornOP 1.28 0.54 0.13 0.05 0.03 0.44 0.34

### 95 Surface Water Pore Water

Scenarios Peak 4

- day 21

- day 60

- day 90

- day Peak 21

- day

Concentration (μg/L)

TXcornOP 4.18 1.56 0.38 0.14 0.10 1.32 1.04


### 2X Application Rate for North Carolina

NCcornWOP 10.60 4.80 1.18 0.44 0.30 1.51 1.25

NCcornESTD 12.50 5.07 1.11 0.43 0.29 2.10 1.74



### Terbufos Sulfoxide (Corn/Sweetcorn)

IAcornstd 3.52 3.45 3.21 2.66 2.33 1.59 1.58

ILCornSTD 8.62 8.43 7.74 6.68 6.07 5.39 5.37

INCornStd 4.96 4.85 4.46 3.75 3.26 2.20 2.19

KSCornStd 15.90 15.60 14.50 12.20 10.70 7.33 7.30

MNCornStd 6.46 6.32 5.96 4.97 4.33 2.90 2.89

MScornSTD 17.00 16.60 15.80 13.40 11.70 12.70 12.70

NCcornESTD 4.26 4.16 3.84 3.18 2.77 1.97 1.96

NECornStd 11.20 10.90 10.10 8.38 7.34 5.05 5.05

OHCornSTD 7.32 7.16 6.55 5.41 4.70 3.78 3.77

PAcornSTD 4.53 4.43 4.14 3.40 2.96 2.27 2.26

CAcornOP 4.92 4.81 4.43 3.65 3.17 2.17 2.16

FLsweetcornOP 26.40 26.40 25.00 24.50 21.20 14.30 14.10

NCcornWOP 11.30 11.10 10.20 8.55 7.46 5.04 5.02

NDcornOP 5.78 5.65 5.15 4.21 3.66 2.45 2.44

ORswcornOP 1.96 1.93 1.78 1.52 1.61 1.09 1.09

TXcornOP 15.80 15.40 14.10 11.70 10.20 7.18 7.15


### 2X Application Rate for North Carolina

NCcornWOP 22.70 22.30 20.30 17.10 14.90 10.10 10.00

NCcornESTD 8.52 8.33 7.68 6.36 5.54 3.94 3.92



### Terbufos Sulfone (Corn/Sweetcorn)

IAcornstd 3.93 3.80 3.48 2.67 2.22 1.70 1.70

ILCornSTD 4.87 4.71 4.33 3.59 3.01 2.59 2.57

INCornStd 4.61 4.46 4.03 3.07 2.54 1.69 1.68

KSCornStd 4.55 4.47 4.18 3.29 2.74 1.88 1.86

MNCornStd 4.20 4.07 3.63 2.85 2.47 1.75 1.74

MScornSTD 5.55 5.37 4.74 3.61 2.98 2.29 2.27

NCcornESTD 3.97 3.85 3.43 2.65 2.20 1.56 1.55

NECornStd 7.57 7.32 6.41 5.02 4.21 2.93 2.93

OHCornSTD 3.70 3.62 3.18 2.40 1.98 1.33 1.32

PAcornSTD 2.43 2.35 2.08 1.60 1.33 0.91 0.90

CAcornOP 1.95 1.92 1.99 1.65 1.35 0.92 0.91

FLsweetcornOP 4.78 4.63 4.43 2.67 2.21 1.61 1.44

NCcornWOP 4.23 4.09 3.59 2.75 2.29 1.56 1.55

### 96 Surface Water Pore Water

Scenarios Peak 4

- day 21

- day 60

- day 90

- day Peak 21

- day

Concentration (μg/L)

NDcornOP 4.30 4.16 3.64 2.74 2.26 1.50 1.49

ORswcornOP 2.22 2.17 1.95 1.73 1.42 0.96 0.95

TXcornOP 10.10 9.77 8.58 6.52 5.39 4.36 4.34


### 2X Application Rate for North Carolina

NCcornWOP 9.76 9.44 8.29 6.36 5.28 3.59 3.57

NCcornESTD 9.16 8.88 7.91 6.13 5.07 3.61 3.58



### Terbufos (Sorghum)

KSsorghumSTD 7.75 3.11 0.73 0.33 0.22 2.57 1.98

TXSorghumOP 19.10 7.64 1.80 0.66 0.44 10.8 8.41


### Terbufos Sulfoxide (Sorghum)

KSsorghumSTD 10.50 10.20 9.54 8.13 7.11 5.25 5.22

TXSorghumOP 23.90 23.30 21.50 18.30 16.00 11.00 10.90


### Terbufos Sulfone (Sorghum)

KSsorghumSTD 4.55 4.43 3.91 3.00 2.48 1.70 1.69

TXSorghumOP 6.52 6.31 5.55 4.21 3.50 2.56 2.56


### Terbufos (Sugar bee

MNSugarbeetSTD 5.62 2.51 0.59 0.21 0.15 1.57 1.26

CASugarbeetwirrgOP 4.14 1.83 0.57 0.21 0.20 0.48 0.41


### Terbufos Sulfoxide (Sugar beet)

MNSugarbeetSTD 7.89 7.71 7.07 5.93 5.92 3.99 3.98

CASugarbeetwirrgOP 9.18 8.98 8.27 6.87 6.00 4.21 4.20


### Terbufos Sulfone (Sugar beet)

MNSugarbeetSTD 4.24 4.10 3.66 2.86 2.37 1.58 1.57

CASugarbeetwirrgOP 0.89 0.86 0.77 0.59 0.49 0.32 0.32



### Table F

- 5. Total Toxic Residue in Water Column: TX Sorghum Scenario

Year Max

Peak 4

- day Max 14 day Max 21 day Max 30 day Max 60 day Max 90 day Annual

1961 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1962 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1963 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1964 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00

1965 0.03 0.02 0.02 0.01 0.01 0.01 0.01 0.00

1966 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1967 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1968 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1969 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00

1970 0.03 0.02 0.01 0.01 0.01 0.01 0.01 0.00

### 97 Year Max

Peak 4

- day Max 14 day Max 21 day Max 30 day Max 60 day Max 90 day Annual

1971 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1972 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1973 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01

1974 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01

1975 0.04 0.03 0.03 0.03 0.03 0.03 0.02 0.01

1976 0.07 0.07 0.07 0.07 0.06 0.06 0.05 0.02

1977 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.02

1978 0.02 0.02 0.02 0.02 0.02 0.02 0.01 0.01

1979 0.03 0.01 0.01 0.01 0.01 0.01 0.01 0.01

1980 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.00

1981 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00

1982 0.04 0.02 0.02 0.02 0.02 0.02 0.01 0.01

1983 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.01

1984 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1985 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1986 0.03 0.02 0.02 0.02 0.02 0.02 0.02 0.01

1987 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.01

1988 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00

1989 0.02 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1990 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.01

90th% (ppm) 0.04 0.02 0.02 0.02 0.02 0.02 0.02 0.01

90th% (ppb) 35.74 24.19 22.47 21.90 21.18 18.47 16.28 8.86



### Table F

- 6. Total Toxic Residue in Benthic Layer: TX Sorghum Scenario

Year Max

Peak 4

- day Max 14 day Max 21 day Max 30 day Max 60 day Max 90 day Annual

1961 0.02 0.02 0.02 0.02 0.02 0.01 0.01 0.00

1962 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1963 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.00

1964 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1965 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1966 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1967 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1968 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1969 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1970 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00

1971 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1972 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1973 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1974 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1975 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

### 98 Year Max

Peak 4

- day Max 14 day Max 21 day Max 30 day Max 60 day Max 90 day Annual

1976 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1977 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1978 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1979 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

1980 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1981 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00

1982 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00

1983 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.00

1984 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1985 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1986 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1987 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1988 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1989 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

1990 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

90th %(ppm) 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00

90th % (ppb) 12.46 12.41 12.15 11.44 10.30 7.40 6.98 3.90



### Summary of Water Modeling of Terbufos and the USEPA Standard Pond

Estimated Environmental Concentrations for terbufos are presented in Table F

- 7 for the USEPA standard pond with the TXsorghumOP field scenario. A graphical presentation of the year

- to

year peaks is presented in Figure F

- 1 . These values were generated with the Surface Water
Concentration Calculator (SWCC Version 1.106).

Table F

- 7 . Estimated Environmental Concentrations (ppb) for Terbufos

Peak (1

- in

- 10 yr) 19.1

4

- day Avg (1

- in

- 10 yr) 7.64

21

- day Avg (1

- in

- 10 yr) 1.80

60

- day Avg (1

- in

- 10 yr) 0.662

365

- day Avg (1

- in

- 10 yr) 0.111

Entire Simulation Mean 0.426E

- 01

### 99 Figure F

- 1. Yearly Peak Concentrations

### 100 Appendix G : Representative T

- REX Input and Output

Scenario : Corn, 7 inch band at planting, 1.3 lb ai/A (0.075 lb ia/1000 ft row) , toxicity based on

TGAI

Table G

- 1. Input

Application Rate 1.3 lb / acre

% AI 100.00%

Avian L D50 (20g) 20.60 mg/kg bw
(100g) 26.23
(1000g) 37.05
Mammalian LD50 (15g) 2.75 mg/kg bw
(35g) 2.22
(1000g) 0.96
Row Spacing 30 inches

Bandwidth 7 inches

Unincorporation 15%



### Table G

- 2. Output and Calculations

# rows acr e

- 1 83.48
row length (ft) 208.71

lb ai/1000 ft row 0.075

bandwidth (ft) 0.58
mg ai/ft2 58.02
exposed mg ai/ft2 8.70

wgt class (grams) Acute RQ

LD 50 /ft 2

Avian 20 21.12

100 3.32

1000 0.23

Mammal 15 211.17

35 111.85

1000 9.05



### Chronic RQs were calculated based on the ratio of exposed mg ai/ft2 to dose

- based NOAEL (mg ai/kg bw).

The avian dietary

- based chronic toxicity value (NOAEC = 5 mg ai/kg diet; MRID 0161574) was converted to a dose equivalent toxicity value. mg ai/kg bw = (mg ai/kg diet * daily food intake)/kg bw. daily food intake = 0.0582 * bw^0.651 (source: SIP v 1.0 ma nual). bw = 1.136 kg (source: mean value from MRID 0161574). NOAEL = 0.278 mg ai/kg bw = (5 mg ai/kg diet * 0.632 kg/day)/1.136 kg bw

### 101 Appendix H : Representative KABAM Input

Scenario: Corn (1. 3 lb ai/A 

### ), crop scenario: MScorn_STD

Table H

- 1. Chemical C haracteristics of Terbufos

Characteristic Value Comments/Guidance 1

Pesticide Name Terbufos

Log K OW 4.71 Enter value from acceptable or supplemental study submitted by registrant or available in scientific literature.

K OW 51286 No input necessary. This value is calculated automatically from the Log K OW value entered above.

K OC (L/kg OC) 17950 Input value used in PRZM/EXAMS to derive EECs. Follow input parameter guidance for deriving this parameter value (USEPA

, 200 9 ).

Time to steady state (T S ; days) 16 No input necessary. This value is calculated automatically from the Log K OW value entered above.

Pore water EEC (μg/L) 8.74 Enter value generated by PRZM/EXAMS benthic file. PRZM/EXAMS EEC represents the freely dissolved concentration of the pesticide in the pore water of the sediment. The appropriate averaging period of the EEC is dependent on the specific pesticide being mod eled and is based on the time it takes for the chemical to reach steady state. Select the EEC generated by PRZM/EXAMS which has an averaging period closest to the time to steady state calculated above. In cases where the time to steady state exceeds 365 d ays, the user should select the EEC representing the average of yearly averages. The peak EEC should not be used.

Water Column EEC (μg/L) 2.44 Enter value generated by PRZM/EXAMS water column file. PRZM/EXAMS EEC represents the freely dissolved concentration of the pesticide in the water column. The appropriate averaging period of the EEC is dependent on the specific pesticide being modeled and is based on the time it takes for the chemical to reach steady state. The averaging period used for the water column EEC should be the same as the one selected for the pore water EEC (discussed above).

1 SWCC is the current model.

### 102 Table H

- 2. Input P arameters for R ate C onstants

Trophic level k 1 (L/kg*d) k 2 (d

- 1 ) k D (kg

food/kg

org/d) k E (d

- 1 ) k M * (d

- 1 )
phytoplankton calculated calculated 0* 0* 0
zooplankton calculated calculated calculated calculated 0

benthic invertebrates calculated calculated calculated calculated 0

filter feeders calculated calculated calculated calculated 0

small fish calculated calculated calculated calculated 0

medium fish calculated calculated calculated calculated 0
large fish calculated calculated calculated calculated 0

* Default value is 0.

k 1 and k 2 represent the uptake and elimination constants

, respectively, through respiration.

k D and k E represent the uptake and elimination constants, respectively, through diet.

k M represents the metabolism rate constant.



### Table H

- 3. Mammalian and A vian T oxicity D ata for Terbufos

Animal Measure of

effect (units) Value Comment

Avian LD 50 (mg/kg bw) 28.6 Northern bobwhite quail

LC 50 (mg/kg

diet) 143 Northern bobwhite quail

NOAEC (mg/kg

- diet) 5 M allard duck

Mineau Scaling

Factor 1.15 Defaul t value

Mammalian LD 50 (mg/kg bw) 1.25 L aboratory rat

NOAEC (mg/kg

- diet) 1 L aboratory rat

### 103 Appendix I : STIR Input and Output

Scenario : Corn

– use with the lowest maximum application rate (1.3 lb ai/A)

Table I

- 1. Inputs

Enter Chemical Use Outdoor
Is the Application a Spray? No
Enter Chemical Molecular Weight (g/mole) 288.4
Enter Chemical Vapor Pressure (mmHg) 3.16E

- 04
Enter Application Rate (lb ai/A ) 1.3

Toxicity Properties

Bird

Enter Lowest Bird Oral LD 50 (mg/kg bw) 28.6
Enter Mineau Scaling Factor 1.15
Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD 50 (mg/kg bw) 1.25

Enter Lowest Rat Inhalation LC 50 (mg/L) 0.0012
Duration of Rat Inhalation Study (hrs) 4
Enter Rat Weight (kg) 0.35



### Table I

- 2. Avian Results (0.020 kg)

Maximum Vapor Concentration in Air at
Saturation (mg/m 3 ) 4.90E+00

Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 6.17E

- 01

Adjusted Inhalation LD 50 1.53E

- 01

Ratio of Vapor Dose to Adjusted Inhalation LD 50 4.03E+00



### Table I

- 3. Mammalian Results (0.015 kg)

Maximum Vapor Concentration in Air at
Saturation (mg/m 3 ) 4.90E+00

Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 7.75E

- 01

Adjusted Inhalation LD 50 7.14E

- 02

Ratio of Vapor Dose to Adjusted Inhalation LD 50 1.08E+01

### 104 Appendix J : SIP Input and Output

SIP employs the following conservative assumptions to derive upper bound exposure estimates: 1) The chemical concentration in drinking water is at the solubility limit in water (at 25 o 

### C). 2) The assessed animals obtain 100% of their daily water needs through drinking water. 3) The daily water need is equivalent to the daily water flux rate as calculated by Nagy and Peterson (1988). 4) The body weight of the assessed bird is equivalent t o the smallest generic bird modeled in T

REX (i.e., 20 g). This assumption results in the highest ratio of exposure to toxicity for the 3 assessed avian body weights of T

- REX (i.e., 20, 100, 1000 g). 5) The body weight of the assessed mammal is equivalent to the largest generic mammal

modeled in T

- REX (i.e., 1000 g). This results in the highest ratio of exposure to toxicity for the 3 assessed mammalian body weights of T

- REX (i.e., 15, 35, 1000 g).

Table J

- 1. Inputs

Parameter Value

Chemical name Terbufos

Solubility (in water at 25 o C; mg/L) 5.4

Mammalian LD 50 (mg/ kg bw ) 1.25

Mammalian test species L aboratory rat

Mammalian NOAEL (mg/ kg bw ) 0.07

Mammalian test species L aboratory rat

Avian LD 50 (mg/ kg bw ) 28.6
Avian test species N orthern bobwhite quail

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg

- diet) 5

Bobwhite quail NOAEC (mg/kg

- diet) 30



### Table J

- 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/ kg bw ) 0.9288 0.9288

Adjusted toxicity value (mg/ kg bw ) 0.9615 0.0538

Ratio of exposure to toxicity 0.9660 17.2507

Conclusion Exposure through drinking water alone is a potential

concern for mammals Exposure through drinking water alone is a potential concern for

mammals



### Table J

- 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/ kg bw ) 4.3740 4.3740

Adjusted toxicity value (mg/ kg bw ) 20.6043 0.2481

Ratio of exposure to acute toxicity 0.2123 17.6326

Conclusion Exposure through drinking water alone is a potential

concern for birds Exposure through drinking water alone is a potential concern for

birds

### 105 APPENDIX K : TerrPlant Input and Output (NC use on corn)

Table K

- 1. Chemical Identity

Chemical Name Terbufos

PC code 105001

Use Corn (NC supplemental label)
Application Method Banded

Application Form Granular
Solubility in Water (ppm) 5.4



### Table K

- 2. Input Parameters Used to Derive EECs

Input Parameter Symbol Value Units

Application Rate A 2.6 lb ai/A

Incorporation I 1 none

Runoff Fraction R 0.01 none

Drift Fraction D 0 none



### Table K

- 3. EECs for Terbufos (lb ai/A)

Description Equation EEC
Runoff to dry areas (A/I)*R 0.026

Runoff to semi

- aquatic areas (A/I)*R*10 0.26
Spray drift A*D 0
Total for dry areas ((A/I)*R)+(A*D) 0.026

Total for semi

- aquatic areas ((A/I)*R*10)+(A*D) 0.26



### Table K

- 4. Plant S urvival and G rowth Data U sed for RQ Derivation. Units are in lb ai/A

Plant type Seedling Emergence Vegetative Vigor

EC 25 NOAEC EC 25 NOAEC

Monocot ND 2 ND ND

Dicot ND 2 ND ND



### Table K

- 5. RQ V alues for P lants in D ry and S emi

- A quatic A reas E xposed to Terbufos

T hrough R unoff.*

Plant Type Listed Status Dry Semi

- Aquatic Spray Drift

Monocot non

- listed N/A N/A N/A

Monocot listed <0.1 0.13 N/A

Dicot non

- listed N/A N/A N/A

Dicot listed <0.1 0.13 N/A

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.

ND = no data N/A = not applicable

### 106 Appendix L : Characterization of Avian and Mammal Risk from Consuming Terbufos Granules

Table L

- 1 . Characterization of Avian Risk from Consuming Terbufos Granules 1

Use Application Method (% incorporation) lb

ai/1000

ft row Product Band

width (in) Row Spacing (in) Exposed

mg ai/ft 2 # Exposed

Granules/

ft 2 ( 2 ) Toxicity (form) 3 # granules to exceed acute LOC 4
0.02 kg bird 0.1 kg bird 1 kg bird

LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC =

0.1

Corn Banded, at planting (85%) 0.15 15G (NC) 7 30 17.4 637

- 1758 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 62 3 45

- 125

0.075 CR 8.7 51 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

15G 319

- 879 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

20G 5 12.18 381 TGAI 6 1 41 8 579 116

4 15.23 476
In furrow, at planting (99%) 0.15 15G (NC) 1 8.12 297

- 820 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

0.075 CR 4.06 24 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

15G 149

- 410 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

20G 127 TGAI 6 1 41 8 579 116
Banded,

postemergence
and at cultivation (85%) 0.075 CR 7 8.7 51 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

15G 319

- 879 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

20G 272 TGAI 6 1 41 8 579 116

### 107 Use Application Method (% incorporation) lb

ai/1000

ft row Product Band

width (in) Row Spacing (in) Exposed

mg ai/ft 2 # Exposed

Granules/

ft 2 ( 2 ) Toxicity (form) 3 # granules to exceed acute LOC 4
0.02 kg bird 0.1 kg bird 1 kg bird

LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC =

0.1 Sorghum Knifed in, at bedding and at planting (99%) 0.065 CR 1 20 3.5 21 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

0.066 15G 3.53 129

- 357 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

0.065 20G 3.5 109 TGAI 6 1 41 8 579 116
Banded, at planting (85%) 0.065 CR 7 7 .5 44 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

0.066 15G 7.56 277

- 764 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

0.065 20G 7 .5 234 TGAI 6 1 41 8 579 116

0.066 15G 5 10.59 388

- 1070 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

0.065 20G 10 .5 328 TGAI 6 1 41 8 579 116

### 108 Use Application Method (% incorporation) lb

ai/1000

ft row Product Band

width (in) Row Spacing (in) Exposed

mg ai/ft 2 # Exposed

Granules/

ft 2 ( 2 ) Toxicity (form) 3 # granules to exceed acute LOC 4
0.02 kg bird 0.1 kg bird 1 kg bird

LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC =

0.1 Sugar

beet Modified in

furrow and knifed in, at planting (99%) 0.075 CR 1 20 4.08 24 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

15G 149

- 412 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

20G 128 TGAI 6 1 41 8 579 116
Banded, at planting and

postemergence (85%) CR 7 8.75 51 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

15G 321

- 884 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

20G 273 TGAI 6 1 41 8 579 116

CR 5 12.25 72 TGAI 1 <1 8 2 109 22

CR 1 <1 6 1 78 16

15G 449

- 1237 TGAI 8

- 21 2

- 4 48

- 132 10

- 27 679

- 1871 136

- 374

15G 3

- 7 1

- 2 16

- 44 3

- 9 226

- 623 45

- 125

20G 383 TGAI 6 1 41 8 579 116

1 Product application methods (timing, lb ai/ft row, band width, and row width) were obtained from the most recent product labe ls.

2 Based on the following granule weights: CR = 0.85 mg/granule (source: American Cyanamid as reported in USEPA

, 1999); 20G = 0 .16 mg/granule (source: email from AMVAC dated 3/3/14); 15G = 0.066

- 0.182 mg/granule (source: Hill and Camardese, 1984 and MRID 41508803 & 41508805). # exposed granules/ft 2 = exposed mg ai/ft 2 /(granule weight as mg * % ai)

3 Toxicity based on TGAI, Bobwhi te quail LD 50 = 28.6 mg ai/kg/bw; 15G, Mallard duck LD 50 = 13.21 mg ai/kg bw; CR

, Cowbird LD 50 = 16.9 mg ai/kg bw

4 Number of granules rounded to nearest whole number.

### 109 Table L

- 2 . Characterization of Mammalian Risk from Consuming Terbufos Granules 1

Use Application Method (% incorporation) lb ai/

1000 ft

row Product Band

width (in) Row Spacing (in) Exposed mg ai/ft 2 # Exposed

Granules/

ft 2 ( 2 ) Toxicity (form) 3 # granules to exceed acute LOC 4
0.015 kg 5 0.035 kg 5 1 kg 5

LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1

Corn Banded, at planting (85%) 0.15 15G (NC) 7 30 17.4 637

- 1758 TGAI <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

0.075 CR 8.7 51 TGAI <1 <1 <1 <1 3 <1

15G 319

- 879 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

20G 5 12.18 381 TGAI <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2

4 15.23 476 TGAI <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2
In furrow, at planting (99%) 0.15 15G (NC) 1 8.12 297

- 820 TGAI <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

0.075 CR 4.06 24 TGAI <1 <1 <1 <1 3 <1

15G 149

- 410 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

20G 127 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2
Banded,

postemergence
and at cultivation (85%) 0.075 CR 7 8.7 51 TGAI <1 <1 <1 <1 3 <1

15G 319

- 879 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

20G 272 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2 Sorghum Knifed in, at bedding and at planting (99%) 0.065 CR 1 20 3.5 21 TGAI <1 <1 <1 <1 3 <1

0.066 15G 3.53 129

- 357 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

0.065 20G 3.5 109 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2
Banded, at planting (85%) 0.065 CR 7 7 .5 44 TGAI <1 <1 <1 <1 3 <1

0.066 15G 7.56 277

- 764 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

0.065 20G 7 .5 234 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2

0.066 15G 5 10.59 388

- 1070 TGAI <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

0.065 20G 10.5 328 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2

### 110 Use Application Method (% incorporation) lb ai/

1000 ft

row Product Band

width (in) Row Spacing (in) Exposed mg ai/ft 2 # Exposed

Granules/

ft 2 ( 2 ) Toxicity (form) 3 # granules to exceed acute LOC 4
0.015 kg 5 0.035 kg 5 1 kg 5

LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1 LOC

= 0.5 LOC

= 0.1

Sugar

beet Modified in

furrow and knifed in, at planting (99%) 0.075 CR 1 20 4.08 24 TGAI <1 <1 <1 <1 3 <1

15G 149

- 412 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

20G 128 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2

Banded, at planting and

postemergence (85%) CR 7 8.75 51 TGAI <1 <1 <1 <1 3 <1

15G 321

- 884 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

20G 273 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2

CR 5 12.25 72 TGAI <1 <1 <1 <1 3 <1

15G 449

- 1237 <1

- 2 <1 1

- 4 <1 18

- 49 4

- 10

20G 383 <1 <1 1 <1 15 3

20G <1 <1 <1 <1 10 2

1 Product application methods (timing, lb ai/ft row, band width, and row width) were obtained from the most recent product labe ls.

2 Based on the following granule weights: CR = 0.85 mg/granule (source: American Cyanamid as reported in USEPA 1999); 20G = 0. 16 mg/granule (source: email from AMVAC dated 3/3/14); 15G = 0.066

- 0.182 mg/granule (source: Hill and Camardese, 1984 and MRID 41508803 & 41508805). # exposed granules/ft 2 = exposed mg ai/ft 2 /(granule weight as mg * % ai)

3 Toxicity based on TGAI, Rat LD 5 0 = 1.25 mg ai/kg/bw; 20G, rat LD 50 = 0.836 mg ai/kg bw

4 Number of granules rounded to nearest whole number.

5 Mammal body weight

### 111 Appendix M : ECOTOXicology D atabase References

Terbufos Refresh Acceptable Bibliography 2012

1. Ayers, A. R.; Duncan, H. E.; Barker, K. R., and Beute, M. K. Effects of Crop Rotation and Nonfumigant Nematicides on Peanut and Corn Yields in Fields Infested with Criconemella Species. 1989; 21, (2):

268

- 275. EcoReference No.: 87066

2. Barillas

- Argueta, J. R. The Influence of Root

- Knot Nematode (Meloidogyne incognita (Kofoid and White) Chitwood 1949) on Growth and Development of Kenaf (Hibiscus cannabinus L.) and Its Control. 1993: 155 p. (UMI# 9400469). EcoReference No.: 157921

3. Belluck, D. and Felsot, A. Bio concentration of Pesticides by Egg Masses of the Caddisfly, Triaenodes tardus Milne. 1981; 26, 299

- 306. EcoReference No.: 2340

4. Bessin, R. T. and Townsend, L. H. Japanese Beetle Larval Control in Field Corn, 1994. 1995; 20, 160

- 161 (20F). EcoReference No.: 110864

5. Biales, A. D.; Bencic, D. C.; Flick, R. L.; Blocksom, K. A.; Lazorchak, J. M., and Lattier, D. L. Proteomic Analysis of a Model Fish Species Exposed to Individual Pesticides and a Binary Mixture. 2011; 101, (1): 196

- 206. EcoReference No.: 156142

6. Boetel, M. A. and Fuller, B. W. Planting

- Time and Post

- Emergence Insecticide Treatments for Controlling Corn Rootworms in South Dakota, 1998. 1999; 24, 209

- 210 (F21). EcoReference No.: 88058

7. Bogatko, W. and Labanowski, G. Chemical Control of the Black Vine Weevil (Otiorrhynchus sulcatus F.) on Ornamental Crops. 1993; 1, (3): 93

- 101. EcoReference No.: 153283

8. Cabrera, J. A.; Pocasangre, L. E.; Pattison, A. B., and Sikora, R. A. Terbufos Biodegradability and Efficacy Against Radopholus si milis in Soils from Banana Cultivation Having Different Histories of Nematicide Use, and the Effect of Terbufos on Plant Growth of In Vitro

- Propagated Musa AAA cv. Grande Naine. 2010; 56, (1): 61

- 67. EcoReference No.: 157846

9. Call, D. J. and Geiger, D. L. Subchronic Toxicities of Industrial and Agricultural Chemicals to Fathead Minnows (Pimephales promelas). Volume I. 1992: 318 p. EcoReference No.: 150898

10. Call, D. J.; Poirier, S. H.; Lindberg, C. A.; Harting, S. L.; Markee, T. P.; Brooke, L. T.; Zarvan, N., and Northcott, C. E. Toxicity of Selected Uncoupling and Acetylcholinesterase

- Inhibiting Pesticides to the Fathead Minnow (Pimephales promelas). 1989: 317

- 336. EcoReference No.: 14097

11. Calvin, D. D. and Losey, J. E. Evaluation of Black Cut worm Insecticide Efficacy, 1989. 1991; 16, 147

- (34F).

EcoReference No.: 155207

12. Campbell, C. D. and Hutchison, W. D. Timing of Insecticides for SRA Management in Southern Minnesota, 1993. 1994; 19, 276

- 277 (140F). EcoReference No.: 106252

13. Castro

- Escobar, A. The Interaction of Acetolactate Synthase Inhibiting Herbicides with Graminicides and Insecticides. 1995: 79 p. (UMI# 1376283)//Publ in part as Ecoref 101249. EcoReference No.:

157919

14. Charlet, L. D.; Oseto, C. Y., and Gulya, T. J. Applica tion of Systemic Insecticides at Planting: Effects on Sunflower Stem Weevil (Coleoptera: Curculionidae) Larvae Numbers, Plant Lodging, and Seed Yield in North Dakota. 1985; 78, (6): 1347

- 1349. EcoReference No.: 112148

### 112 15. Chaves, N. P.; Pocasangre, L. E.; Elango, F.; Rosales, F. E., and Sikora, R. Combining Endophytic Fungi and Bacteria for the Biocontrol of Radopholus similis (Cobb) Thorne and for Effects on Plant Growth. BEH, 2009; 122, (3): 472

- 478. EcoReference No.: 157847

16. Chio, H.; Chang, C. S.; Metcalf, R. L., and Shaw, J. Susceptibility of Four Species of Diabrotica to Insecticides. 1978; 71, (3): 389

- 393. EcoReference No.: 63297

17. Choung, C. B.; Hyne, R. V.; Mann, R. M.; Stevens, M. M., and Hose, G. C. Developmental Toxicity of Two Common Corn Pesticides to the Endangered Southern Bell Frog (Litoria raniformis). 2011; 159,

2648

- 2655. EcoReference No.: 153858 ; 2011a

18. Choung, C. B.; Hyne, R. V.; Stevens, M. M., and Hose, G. C. A Low Concentration of Atrazine does not

Influence t he Acute Toxicity of the Insecticide Terbufos or Its Breakdown Products to Chironomus tepperi. BEH,MOR. Catherine.Choung@environment.nsw.gov.au//Department of Biological Sciences, Macquarie University, Macquarie University, NSW, 2109, Australia. 2010; 19, (8): 1536

- 1544. EcoReference No.: 153818

19.

--- . Toxicity of the Insecticide Terbufos, Its Oxidation Metabolites, and the Herbicide Atrazine in Binary Mixtures to Ceriodaphnia cf dubia. Department of Biological Sciences, Macquarie University,

Balaclava Road, Macquarie University, NSW 2109, Australia. catherine.choung@environment.nsw.gov.au//: 2011; 60, (3): 417

- 425. EcoReference No.: 153854 ; 2011b

20. DePew, L. J. and Hooker, M. L. Effect of Insecticide Placement at Planting for Control of Greenbug ( Homoptera: Aphididae) on Grain Sorghum. 1987; 80, (2): 490

- 493. EcoReference No.: 113373

21. Diehl, K. E.; Taylor, S. L.; Simpson, D. M., and Stoller, E. W. Effect of Soil Organic Matter on the Interaction Between Nicosulfuron and Terbufos in Corn (Zea m ays). 1995; 43, (2): 306

- 311.

EcoReference No.: 101802

22. Downard, R. W.; Morishita, D. W.; Dexter, A. G.; Wilson, R., and Hein, G. L. Interaction Between Triflusulfuron and Organophosphate or Carbamate Insecticides in Sugarbeet. 1999; 36, (4): 47

- 81.

EcoReference No.: 157887

23. Fornstrom, K. J. and Miller, S. D. Insecticide Placement Interactions with Preplant Herbicides in Sugarbeets. 1995; 32, (2/3): 79

- 88. EcoReference No.: 157890

24. Foster, R. E. and Brust, G. E. Effects of Insecticides Appl ied to Control Cucumber Beetles (Coleoptera: Chrysomelidae) on Watermelon Yields. 1995; 14, (8): 619

- 624. EcoReference No.: 92727

25. Frazier, T. L. and Nissen, S. J. Influence of Crop Safeners on the Interaction of Primisulfuron and Terbufos in Corn (Z ea mays). 1994; 42, (2): 168

- 171. EcoReference No.: 101798

26. Gable, R. H.; Emfinger, K. D.; Leonard, B. R., and Temple, J. Evaluation of Selected Insecticides Against Sugarcane Beetle and Cutworms in Field Corn, 2004. 2005; 30, 2 p. (F21). EcoReference No.:

110034

27. Green, J. M. and Ulrich, J. F. Response of Maize (Zea mays) Inbreds and Hybrids to Rimsulfuron. 1994; 40,

187

- 191. EcoReference No.: 66597

28. Greenlee, A. R.; Ellis, T. M., and Berg, R. L. Low

- Dose Agrochemicals and Lawn

- Care Pestici des Induce Developmental Toxicity in Murine Preimplantation Embryos. 2004; 112, (6): 703

- 709.

EcoReference No.: 82041

### 11 3 29. Haas, M. J. and Landis, D. A. 1st Generation European Corn Borer Larvicide Trial, 1995. 1996; 21, 219

- (36F). EcoReference No.: 9550 1

30. Hammond, R. B. Phytotoxicity of Soybean Caused by the Interaction of Insecticide

- Nematicides and Metribuzin. Dep. Entomol.,Ohio Agric. Res. Dev. Cent.,Wooster,OH//:1983; 76, (1): 17

- 19.

EcoReference No.: 103910

31. Henzell, R. F.; Skinner, R. A. , and Clements, R. O. Insecticides for Control of Adult Grass Grub, Costelytra zealandica (White) V. Screening and Behaviour of Insecticides in Soil Bioassays. 1983; 26, (1): 129

- 133. EcoReference No.: 79045

32. Hoffmann, M. P.; Kirkwyland, J. J., and Ga rdner, J. Impact of Western Corn Rootworm (Coleoptera: Chrysomelidae) on Sweet Corn and Evaluation of Insecticidal and Cultural Control Options. 2000; 93, (3): 805

- 812. EcoReference No.: 58574

33. Johnson, D. R.; Studebaker, G., and Kimbrough, J. Contro l of Thrips in Cotton with In

- Furrow Insecticides, 1991. 1993; 18, 230

- (55F). EcoReference No.: 150470

34. Kappelman, A. J. Jr. Effect of Fungicides, Insecticides, and Their Combinations on Stand Establishment and Yield of Cotton. 1980; 64, (12): 1076

- 10 78. EcoReference No.: 96622

35. Kwon, C. S.; Kells, J. J., and Penner, D. Combined Effects of Acetolactate Synthase

- Inhibiting Herbicides with Terbufos and Piperonyl Butoxide on Corn (Zea mays) and Soybean (Glycine max). 1995; 9, (4): 696

- 702. EcoReferen ce No.: 75595

36. Lentz, G. L.; Hayes, R. M., and Chambers, A. Y. Interactions of Insecticide

- Nematicides, Metribuzin, and Environment on Soybean Injury and Yield. 1985; 78, (6): 1217

- 1221. EcoReference No.: 101285

37. Mize, T.; Wilde, G., and Smith, M . T. Chemical Control of Chinch Bug and Greenbug on Seedling Sorghum with Seed, Soil, and Foliar Treatments. 1980; 73, (4): 544

- 547. EcoReference No.: 113402

38. Morton, C. A. Selectivity and Efficacy of Sulfonylurea Herbicides and Wild

- Proso Millet Comp etition in Field and Sweet Corn. 1993: 173 p. (UMI# 9318633), Publ in Part as Ecoref 101253, Ecoref 62641.

EcoReference No.: 157923

39. Nendza, M. and Wenzel, A. Discriminating Toxicant Classes by Mode of Action 1. Ecotoxicity Profiles.

2006: 1

- 12. EcoRe ference No.: 119380

40. Nielsen, D. G. and Boggs, J. F. Topical Toxicity of Insecticides to First

- Instar Black Vine Weevil (Coleoptera: Curculionidae). 1985; 78, (5): 1114

- 1117. EcoReference No.: 112759

41. Noetzel, D. and Kellesvig, C. Comparison of Seed Coating and Granular Systemics for Flea Beetle Control, 1992. 1993; 18, 194

- (12F). EcoReference No.: 105630

42. Noetzel, D. and Nyegaard, C. Flea Beetle Control in Canola, 1987. 1988; 13, 196

- (30F). EcoReference No.:

88850

43. Noetzel, D. and Putnam, D. Seed Coating for Flea Beetle Control, 1992. 1993; 18, 193

- 194 (11F).

EcoReference No.: 105631

44. Noetzel, D. M. Flea Beetle Control in Canola, Roseau, MN, 1994. 1996; 21, 207

- (20F) . EcoReference No.:

105935

45. Oleson, J. D.; McNutt, J. J.; Pruisner, R. D., and Tollefson, J. J. Corn Rootworm Larval Control, 1994. 1995; 20, 174

- 176 (37F). EcoReference No.: 106400

### 114 46. Oleson, J. D.; McNutt, J. J.; Tollefson, J. J., and Wang, X. Seedcorn Maggot Control, 1996. 1997; 22, 224.

EcoReference No.: 95648

47. Oleson, J. D.; McNutt, J. J.; Warshaw, J. A., and Tollefson, J. J. Corn Rootworm Larval Control in Iowa, 1993. 1994; 19, 200

- 203 (37F). EcoReference No.: 106407

48. Oleson, J. D.; Nowatzki, T. M., and Tollefson, J. J. Field Corn, Wireworm Lar val Control, 1998. 1999; 24,

217

- 218 (F30). EcoReference No.: 88098

49. Peairs, F. B. and Pilcher, S. D. Second Generation European Corn Borer, Handplots, Wray, CO, 1985. 1986; 11, 242

- 243 (316). EcoReference No.: 88670

50. Rogers, D. J. and Brier, H. B. Application Methods for Granular Insecticides to Control Heteronyx piceus Blanchard (Coleoptera: Scarabaeidae) Larvae in Peanuts in Queensland. 1992; 7, (2): 48

- 50.

EcoReference No.: 154187

51. Ruppel, R. F. and Laughlin, C. W. Toxicity of Some Soil Pesticides to Earthworms. 1977; 50, (1): 113

- 118.

EcoReference No.: 38599

52. Seymour, R. C.; Campbell, J. B., and Wright, R. J. Control of European Corn Borer on Whorl Stage Corn in West Central Nebraska, 1992. 1994; 19, 207

- 208 (43F). EcoReference No. : 121354

53. Shapiro, C. A.; Echtenkamp, G. W.; Witkowski, J. F., and Hunt, T. E. Effects of Manure, Hybrid Root Strength, and Reduced Rates of Insecticide on Corn Rootworm (Coleoptera: Chrysomelidae) Injury to Corn. 2002; 21, (2): 95

- 107. EcoReference N o.: 157858

54. Smart, J. R. and Bradford, J. M. CGA

- 152005 and Terbufos in Corn and Grain Sorghum. 1995; 48, 77

- 81.

EcoReference No.: 157860

55. Tasistro, A. and Mihm, J. A. Control of Fall Armyworm in Field Corn, 1985. 1987; 12, 223

- 224 (260).

EcoRe ference No.: 88711

56. Tetreault, G. E. Metabolism of Carbaryl, Chlorpyrifos, DDT, and Parathion in the European Corn Borer: Effects of Microsporidiosis on Toxicity and Detoxication. 1985: 86 p. (UMI# 8600331).

EcoReference No.: 87626

57. Tien, C. J. and Chen, C. S. Assessing the Toxicity of Organophosphorous Pesticides to Indigenous Algae with Implication for Their Ecotoxicological Impact to Aquatic Ecosystems. 2012; 47, (9): 901

- 912.

EcoReference No.: 157805

58. Tindall, K. V.; Gable, R.; Emfinger , K., and Leonard, B. R. Evaluation of Selected Insecticides Treatments Against Soil Insects in Field Corn, 2004. 2005; 30, 2 p. (F31). EcoReference No.: 102135

59. Tomlin, A. D. and Gore, F. L. Effects of Six Insecticides and a Fungicide on the Numbers and Biomass of Earthworms in Pasture. 1974; 12, (4): 487

- 492. EcoReference No.: 35493

60. Wolfe, M. F. Age

- Dependent Toxicity and Comparative Metabolism of Counter and Diazinon in Red

Winged Blackbirds and European Starlings. 1992: 192 p. (UMI# 9321061) (Publ in part as 55700).

EcoReference No.: 157889

61. Wright, R. J.; Scharf, M. E.; Meinke, L. J.; Zhou, X.; Siegfried, B. D., and Chandler, L. D. Larval Susceptibility of an Insecticide

- Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae) Popul ation to Soil Insecticides: Laboratory Bioassays, Assays of Detoxification Enzymes, and Field Performance. 2000; 93, (1): 7

- 13. EcoReference No.: 58594

### 115 Terbufos Refresh Acceptable Bibliography April 2008

1. Barrett, G. W.; Haviland, C. S., and Taylor, D. H. Perturbation Effects on Deer Mouse Populations in Corn Agroecosystems. 1990; 90, (4): 125

- 129. Rec #: 80. EcoReference No.: 101173

2. Belluck, D. and Felsot, A. Bioconcentration of Pesticides by Egg Masses of the Caddisfly, Triaenodes tardus

Milne . 1981; 26, 299

- 306. Rec #: 150. EcoReference No.: 2340

3. Block, E. K.; Lacher, T. E. Jr.; Brewer, L. W.; Cobb III, G. P., and Kendall, R. J. Population Responses of Peromyscus Resident in Iowa Cornfields Treated with the Organophosphorus Pesticide COUNTER. MOR,POP,ACC,BCM,REP. Department of Wildlife and Fisheries Sciences, 210 Nagle Hall, Texas A&M University, College Station, TX 77843

- 2258, USA: ENV; 1999 Jun; 8, (3): 189

- 200. Rec #:

320. EcoReference No.: 67171

4. Block, E. K.; Lacher, T. E. Jr ., and Kendall, R. J. Effects of the Organophosphate Pesticide Counter on Laboratory Deer Mice (Peromyscus maniculatus). 1993; 12, 377

- 383. Rec #: 260. EcoReference

No.: 63034

5. Brecken

- Folse, J. A.; Mayer, F. L.; Pedigo, L. E., and Marking, L. L. Acut e Toxicity of 4

- Nitrophenol, 2,4

- Dinitrophenol, Terbufos and Trichlorfon to Grass Shrimp (Palaemonetes spp.) and Sheepshead Minnows (Cyprinodon variegatus) as Affected by Salinity and Temperature. 1994; 13, (1): 67

- 77.

Rec #: 110. EcoReference No.: 13273

6. Brewer, R. A.; Carlock, L. L.; Hooper, M. J.; Brewer, L. W.; Cobb III, G. P., and Kendall, R. J. Toxicity, Survivability, and Activity Patterns of Northern Bobwhite Quail Dosed with the Insecticide Terbufos. 1996; 15, (5): 750

- 753. Rec #: 30. EcoRefer ence No.: 100310

7. Call, D. J.; Poirier, S. H.; Lindberg, C. A.; Harting, S. L.; Markee, T. P.; Brooke, L. T.; Zarvan, N., and Northcott, C. E. Toxicity of Selected Uncoupling and Acetylcholinesterase

- Inhibiting Pesticides to the Fathead Minnow (Pimepha les promelas). 1989: 317

- 336. Rec #: 130. EcoReference No.: 14097

8. Castro, B. A.; Riley, T. J., and Leonard, B. R. Evaluation of Selected Insecticides for Control of Red Imported Fire Ant in Grain Sorghum, 1994. 1995; 20, 232

- 233 (110F). Rec #: 60. Eco Reference

No.: 101148

9. Clements, R. O.; Bentley, B. R., and Jackson, C. A. The Impact of Granular Formulations of Phorate, Terbufos, Carbofuran, Carbosulfan and Thiofanox on Newly Sown Italian Ryegrass (Lolium multiflorum). 1986; 5, (6): 389

- 394. Rec # : 350. EcoReference No.: 79049

10. Cobb, G. P.; Hol, E. H.; Allen, P. W.; Gagne, J. A., and Kendall, R. J. Uptake, Metabolism and Toxicity of Terbufos in the Earthworm (Lumbricus terrestris) Exposed to Counter

- 15G in Artificial Soils. 1995; 14, (2): 279

- 285. Rec #: 190. EcoReference No.: 40056

11. Fayez, M. Interactions of Some Nematicides with Azospirillum lipoferum and the Growth of Zea maize. 1990; 153, (4): 219

- 223. Rec #: 70. EcoReference No.: 101172

12. Fornstrom, C. B.; Landrum, P. F.; Weissko pf, C. P., and LaPoint, T. W. Effects of Terbufos on Juvenile Red Swamp Crayfish (Procambarus clarkii): Differential Routes of Exposure. 1997; 16, (12): 2514

- 2520.

Rec #: 140. EcoReference No.: 18475

13. Geiger, D. L.; Brooke, L. T., and Call, D. J. Acu te Toxicities of Organic Chemicals to Fathead Minnows (Pimephales promelas), Volume 5. 1990: 332 p. Rec #: 160. EcoReference No.: 3217

### 116 14. Godfrey, L. D. and Holtzer, T. O. Effects of Soil

- Incorporated Insecticides and Foliar

- Applied Chemicals on

Corn Gas

- Exchange Parameters. 1992; 11, (5): 427

- 432. Rec #: 280. EcoReference No.: 64451

15. Gough, N. Chemical Control of the Earthworm Amynthas rodericensis (Grube) in Pots in Nurseries. 1986; 43, (1): 29

- 31. Rec #: 400. EcoReference No.: 86931

16. Gree n, J. M. and Ulrich, J. F. Response of Corn (Zea mays L.) Inbreds and Hybrids to Sulfonylurea Herbicides. 1993; 41, 508

- 516. Rec #: 300. EcoReference No.: 66596

17. Greenlee, A. R.; Ellis, T. M., and Berg, R. L. Low

- Dose Agrochemicals and Lawn

- Care Pest icides Induce Developmental Toxicity in Murine Preimplantation Embryos. 2004; 112, (6): 703

- 709. Rec #: 380

Notes: EcoReference No.: 82041

18. Haque, A. and Ebing, W. Toxicity Determination of Pesticides to Earthworms in the Soil Substrate. 10944: 1983; 90, (4): 395

- 408 (OECDG Data File). Rec #: 200. EcoReference No.: 40493

19. Hill, E. F. and Camardese, M. B. Lethal Dietary Toxicities of Environmental Contaminants and Pesticides to Coturnix. 1986: 147 p. Rec #: 210. EcoReference No.: 50181

20.

--- . T oxicity of Anticholinesterase Insecticides to Birds: Technical Grade Versus Granular Formulations. 1984; 8, (6): 551

- 563. Rec #: 180. EcoReference No.: 37111

21. Howe, G. E.; Marking, L. L.; Bills, T. D.; Rach, J. J., and Mayer, F. L. Jr. Effects of Wate r Temperature and pH on Toxicity of Terbufos, Trichlorfon, 4

- Nitrophenol and 2,4

- Dinitrophenol to the Amphipod Gammarus pseudolimnaeus and Rainbow Trout (Oncorhynchus mykiss). 1994; 13, (1): 51

- 66.

Rec #: 120. EcoReference No.: 13274

22. Kataria, H. R. and Verma, P. R. Interactions of Fungicide and Insecticide Combinations Against Rhizoctonia Damping

- Off and Root Rot in Canola. 1993; 123, 233

- 246. Rec #: 370. EcoReference No.: 81126

23. Kennedy, C. W. Phytotoxicity in Pearl Millet Varies Among In

- Furro w Insecticides. 2002; 21, (9): 799

- 802.

Rec #: 390. EcoReference No.: 86668

24. Kim, J. R.; Kim, H. J., and Kwon, O. S. Acetylcholinesterase and Neuropathy Target Esterase Activity in Female and Male Rats Exposed to Pesticide Terbufos. 2005; 20, (1): 14 9

- 156. Rec #: 20

Notes: EcoReference No.: 100309

25. Kwon, C. S. and Penner, D. The Interaction of Insecticides with Herbicide Activity. 1995; 9, (1): 119

- 124.

Rec #: 340. EcoReference No.: 73949

26. Labisky, R. F. Responses of Pheasants to Simulated Field Applications of Counter, An Organophosphate Insecticide. 1975; 39, (1): 174

- 178. Rec #: 170. EcoReference No.: 35316

27. Landrum, P. F.; Fisher, S. W.; Hwang, H., and Hickey, J. Hazard Evaluation of Ten Organophosphorus Insecticides Against the Mid ge, Chironomus riparius via QSAR. MOR. P.F.Landrum, Great Lakes Environmental Research Laboratory, NOAA, Ann Arbor, MI, 48105. 1999; 10, (5): 423

- 450.

Rec #: 490. EcoReference No.: 67687

28. Langton, S. J. Field Corn Tolerance to Acetolactate Synthase Inhibiting Herbicides and Weed Control in Sethoxydim Resistant Field Corn. 1997: 209 p. Rec #: 470. EcoReference No.: 99110

29. Matocha, J. E. and Hopper, F. L. Influence of Terbufos and Nicosulfuron on Iron Chlorosis and Growth of Corn. 2001; 24, (9): 1 445

- 1455. Rec #: 50. EcoReference No.: 101099

### 117 30. Messaad, I. A.; Peters, E. J., and Young, L. Thermal Tolerance of Red Shiner (Cyprinella lutrensis) After Exposure to Atrazine, Terbufos, and Their Mixtures. 2000; 64, (5): 748

- 754. Rec #: 220

Note s: EcoReference No.: 52188

31. Morton, C. A.; Harvey, R. G.; Kells, J. J.; Landis, D. A.; Lueschen, W. E., and Fritz, V. A. In

- Furrow Terbufos Reduces Field and Sweet Corn (Zea mays) Tolerance to Nicosulfuron. 1993; 7, (4): 934

- 939. Rec #: 90. EcoReferen ce No.: 101253

32. Morton, C. A.; Harvey, R. G.; Wedberg, J. L.; Kells, J. J.; Landis, D. A., and Lueschen, W. E. Influence of Corn Rootworm Insecticides on the Response of Field Corn (Zea mays) to Nicosulfuron. 1994; 8, (2): 289

- 295. Rec #: 250. EcoRefe rence No.: 62641

33. Radford, B. J. and Allsopp, P. G. Use of Insecticides and a Press Wheel to Control Soil Insects Affecting Sorghum and Sunflower Establishment in Southern Queensland. 1987; 26, (2): 161

- 167. Rec #: 270

Notes: EcoReference No.: 64369

34. Reed, J. P.; Keaster, A. J.; Kremer, R. J., and Kerr, H. D. Activities and Degradation of Several Insecticides and Herbicides in Soils Poised for Enhanced Carbamate and Thiocarbamate Degradation. 1989; 24, (1): 23

- 35. Rec #: 40. EcoReference No.: 1009 01

35. Simpson, D. M.; Diehl, K. E., and Stoller, E. W. 2,4

- D Safening of Nicosulfuron and Terbufos Interaction in Corn (Zea mays). 1994; 8, (3): 547

- 552. Rec #: 100. EcoReference No.: 101254

36. Sinclair, P. J.; Neeson, R. J., and Williams, P. A. Phyt otoxicity of Some Organophosphate Insecticides to Onions and Carrots During Germination and Emergence. P.J.Sinclair, Hortic. Res. Advisory Stn., New South Wales Agric., Griffith, 2680, Australia. 1992; 7, (1): 23

- 25. Rec #: 410. EcoReference

No.: 93323

37

. Singh, B. D.; Singh, R. B.; Singh, R. M.; Singh, Y., and Singh, J. Effect of Insecticides on Germination, Early Growth and Cytogenetic Behavior of Barley (Hordeum vulgare). 1979; 19, (3): 127

- 132. Rec #: 240

Notes: EcoReference No.: 59664

38. Singh, B . D.; Singh, Y.; Singh, R. B.; Singh, R. M.; Sarma, N. D. R. K., and Singh, J. Cytogenetic Aberrations & Morphological Changes Induced by Insecticide Treatments of Barley Seeds. Dept. Genetics Plant Breeding, Fac. Agric., Banaras Hindu Univ., Varanasi, Ind ia. 1977; 15, (8): 688

- 691.

Rec #: 480. EcoReference No.: 99386

39. Smith, C. R.; Funke, B. R., and Schulz, J. T. Effects of Insecticides on Acetylene Reduction by Alfalfa, Red Clover and Sweetclover. 1978; 10, (6): 463

- 466. Rec #: 290. EcoReference No. : 64478

40. Stall, W. M. and Bewick, T. A. Sweet Corn Cultivars Respond Differentially to the Herbicide Nicosulfuron. GRO,POP. W.M.Stall, Veg. Crops Dep., Univ. Florida, Gainesville, FL, 32611. 1992; 27, (2): 131

- 133. Rec #: 330. EcoReference No.: 69008

41. Tank, S. L.; Brewer, L. W.; Hooper, M. J.; Cobb III, G. P., and Kendall, R. J. Survival and Pesticide Exposure of Northern Bobwhites (Colinus virginianus) and Eastern Cottontails (Sylvilagus floridanus) on Agricultural Fields Treated with Counter 15 G. 1993; 12, (11): 2113

- 2120.

Rec #: 10. EcoReference No.: 100308

42. Thomas, B. V. Organophosphate Insecticides: Metabolism, Excretion, Forensic and Mechanistic Investigations in Fish. 1996: 149 p. Rec #: 450. EcoReference No.: 95974

43. Tomlin, A. D. Toxicity of Soil Applications of Insecticides to Three Species of Springtails (Collembola) Under Laboratory Conditions.1975; 107,769

- 774. Rec #: 310. EcoReference No.: 67151

### 118 44. Trevathan, L. E. and Robbins, J. T. Yield of Sorghum and Soybean, Grown a s Monocrops and in Rotation, as Affected by Insecticide and Nematicide Applications.1995; 25, (2): 125

- 134. Rec #: 360.

EcoReference No.: 79057

45. Tu, C. M. Effects of Pesticides on Activities of Enzymes and Microorganisms in a Clay Soil. 1981; 16, (2):

179

- 191. Rec #: 440. EcoReference No.: 93646

46.

--- . Influence of Pesticides on Acetylene Reduction and Growth of Microorganisms in an Organic Soil. 1979; 14, (6): 617

- 624. Rec #: 430. EcoReference No.: 93645

47. Williams, B. J. and Harvey, R. G. Ni cosulfuron Tolerance in Sweet Corn (Zea mays) as Affected by Hybrid, Rootworm Insecticide, and Nicosulfuron Treatment. B.J.Williams, Coll. Agric. and Life Sci., Univ. Wisconsin, Madison, WI, 53706, USA. 1996; 10, (3): 488

- 494.

Notes: EcoReference No.: 934 17

48. Wilson, H. R. and Eisley, J. B. Evaluation of Soil Insecticides in Ohio, 1993. 1994; 19, 213

- 214 (51F).

Rec #: 460. EcoReference No.: 97877

49. Wolfe, M. F. and Kendall, R. J. Age

- Dependent Toxicity of Diazinon and Terbufos in European Starlin gs (Sturnus vulgaris) and Red

- Winged Blackbirds (Agelaius phoeniceus). 1998; 17, (7): 1300

- 1312.

Rec #: 230. EcoReference No.: 55700

Terbufos Refresh Not Acceptable Bibliography April 2012

1. Andow, D. A. Fate of Eggs of First

- Generation Ostrinia nubilalis (Lepidoptera: Pyralidae) in Three Conservation Tillage Systems. 1992; 21, (2): 388

- 393. EcoReference No.: 121463

2. Baerg, R. J. Basis of Imazethapyr Selectivity in Cowpea (Vigna senensis), Interactions Between Insecticides and Cytochrome P450 Activities, and Cytochrome P450 Monooxyenase Metabolism of Imazethapyr. 1994: 135 p. (UMI# 9519769). EcoReference No.: 157920

3. Bailey, J. A. and Kapusta, G. Soil Insecticide and Placement Influence Corn (Zea mays) Tolerance to Nicosulfuron. 1994; 8, ( 3): 598

- 606. EcoReference No.: 63642

4. Ben

- Yakir, D. Gol'Berg, A. M., and Chen, M. Laboratory Efficacy Screening of Insecticides for Control of Maladera matrida Larvae. Dep. Entonol. Volcani Center, Bet Dagan 50250, Israel. 1995; 23, (2):

119

- 125. EcoRe ference No.: 153450

5. Diehl, K. E. and Stoller, E. W. Effect of Simulated Rainfall, Insecticide Formulation, and Insecticide Application Method on the Interaction Between Nicosulfuron and Terbufos in Corn (Zea mays). 1995; 9, (1): 80

- 85. EcoReference No .: 101252 ; 1995

6. Diehl, K. E.; Stoller, E. W., and Barrett, M. In Vivo and In Vitro Inhibition of Nicosulfuron Metablism by Terbufos Metabolites in Maize. 1995; 51, 137

- 149. EcoReference No.: 157646 ; 1995

7. Ennik, G. C. and Hofman, T. B. Response of Pasture Grass to Thionazin and Other Pesticides. 1977: 41 p.

EcoReference No.: 107086

8. Gentile, J. M.; Gentile, G. J.; Bultman, J.; Sechriest, R.; Wagner, E. D., and Plewa, M. J. An Evaluation of the Genotoxic Properties of Insecticides Following Plan t and Animal Activation. 1982; 101, (1): 19

- 29.

EcoReference No.: 79052

### 119 9. Gibson, S. V.; Besch

- Williford, C.; Raisbeck, M. F.; Wagner, J. E., and McLaughlin, R. M. Organophosphate Toxicity in Rats Associated with Contaminated Bedding. Department of Ve terinary Pathology, University of Missouri, Columbia 65211. 1987; 37, (6): 78 9

- 791. EcoReference No.: 157917

10. Hein, G. L. and Wilson, R. G. Effect of Insecticide Placement on the Phytotoxicity of Planting Time

Insecticides and Their Interaction with Herbicides. 1995; 32, (4): 185

- 199. EcoReference No.:

157888

11. Holshouser, D. L.; Chandler, J. M., and Smith, H. R. The Influence of Terbufos on the Response of Five Corn (Zea mays) Hybrids to CGA

- 136872. 1991; 5, (1): 165

- 168. EcoReference No.: 10125 7

12. Hurej, M.; Krol, J., and Pomorski, R. J. Effects of Granular Insecticides or Sugar

- Beet Dressing on Some Sugar

- Beet Pests and Soil Fauna of Mites and Springtails. 1994; 63, (1

- 2): 183

- 196. EcoReference

No.: 104327

13. Jauregui, J.; Valderrama, B. , and Vazquez

- Duhalt, R. Biocatalytic Oxidation of Organophosphorous Pesticides by White Rot Fungi. 2001; 6, 17

- 25. EcoReference No.: 104020

14. Kurtak, D.; Meyer, R.; Ocran, M.; Ouedraogo, M.; Renaud, P.; Sawadogo, R. O., and Tele, B. Management

of Inse cticide Resistance in Control of the Simulium damnosum Complex by the Onchocerciasis Control Programme, West Africa: Potential Use of Negative Correlation Between Organophosphate Resistance and Pyrethroid Susceptibility. 1987; 1, (2): 137

- 146. EcoReferenc e No.: 101217:

15. Kwon, C. S. Influence of Antidotes, MFO Inhibitors, Insecticides, and Corn Hybrids on ALS

- Inhibiting Herbicide Activity. 1993: 183 p. (UMI#9418019), Publ in Part as Ecoref 73949, 75594, 75595,

101453. EcoReference No.: 157922

16. La ngton, S. J. Field Corn Tolerance to Acetolactate Synthase Inhibiting Herbicides and Weed Control in Sethoxydim Resistant Field Corn. 1997: 209 p. EcoReference No.: 99110

17. Lim, K. P.; Yule, W. N., and Harris, C. R. The Toxicity of Ten Insecticides to Third Stage Grubs of Phyllophaga anxia (Leconte) (Coleoptera: Scarabaeidae). 1980; 61, (2): 55

- 60. EcoReference No.:

100602

18. Messaad, I. A. Histomorphological Responses of Red Shiner (Cyprinella lutrensis) to Atrazine, Terbufos, and

Their Mixture. 19 96: 189 p. (UMI# 9712520) (Publ in Part as 52188). EcoReference No.: 157806

19. Nielsen, D. G. and Boggs, J. F. Influence of Soil Type and Moisture on Toxicity of Insecticides to First

- Instar Black Vine Weevil (Coleoptera: Curculionidae). 1985; 78, (4): 753

- 756. EcoReference No.: 112147

20. Rahman, A. and James, T. K. Enhanced Activity of Nicosulfuron in Combination with Soil

- Applied Insecticides in Corn (Zea mays). 1993; 7, (4): 824

- 829. EcoReference No.: 64240

21. Reed, J. P.; Keaster, A. J.; Kremer, R. J., and Krause, G. F. Synergistic and Antagonistic Responses of Soil

Insecticide

- Herbicide Combinations for Corn Rootworm, Diabrotica spp. Control. 1989; 24, (4):

325

- 334. EcoReference No.: 106095

22. Rothe, I.; Dexter, A. G., and Luecke, J. L . Impact of Injury from Late Season Sequential Glufosinate Applications on Sugarbeet Yield. Dept. of Plant Sciences, North Dakota State University, Loftsgard Hall, Fargo, ND 58105. 2004; 41, (4): 119

- 136. EcoReference No.: 155497

23. Rovesti, L. and Deseo, K. V. Compatibility of Pesticides with the Entomopathogenic Nematode, Heterorhabditis heliothidis. 1991; 37, (1): 11 3

- 116. EcoReference No.: 102311

### 120 24. Schmenk, R. and Kells, J. J. Effect of Soil

- Applied Atrazine and Pendimethalin on Velvetleaf ( Abutilon theophrasti) Competitiveness in Corn. Prof. R. Schmenk, Novartis Crop Protection, Inc., 88 Lamppost Lane, Lancaster, PA 17602. 1998; 12, (1): 47

- 52. EcoReference No.: 72879

25. Shin, J. D. Characterization of Plant Responses to Herbicides and S afeners. 1995: 137 p. (UMI#9604845).

EcoReference No.: 114707

26. Stenersen, J.; Brekke, E., and Engelstad, F. Earthworms for Toxicity Testing; Species Differences in Response Towards Cholinesterase Inhibiting Insecticides. 1992; 24, (12): 1761

- 1764. Ec oReference

No.: 74718

27. Stinner, B. R.; Krueger, H. R., and McCartney, D. A. Insecticide and Tillage Effects on Pest and Non

- Pest Arthropods in Corn Agroecosystems. 1986; 15, (1): 11

- 21. EcoReference No.: 108172

28. Stoltz, R. L. and Matteson, N. A. Sugarbeet Root Maggot Control, 1991. 1992; 17, 285

- (125F). EcoReference

No.: 79793

29. Wilcut, J. W.; Richburg III, J. S., and Walls, F. R. Jr. Response of Johnsongrass (Sorghum halepense) and

Imidazolinone

- Resistant Corn (Zea mays) to AC 263,222. 1999; 13, (3): 484

- 488. EcoReference

No.: 101799

Terbufos Refresh Not Acceptable Bibliography April 2008

1. Balcomb, R.; Stevens, R., and Bowen II, C. Toxicity of 16 Granular Insecticides to Wild

- Caught Songbirds. 1984; 33, (3): 302

- 307. Rec #: 10. EcoRefere nce No.: 35027

2. Boermans, H. J.; Black, W. D.; Chesney, J.; Robb, W., and Shewfelt, W. Effect of Terbufos Poisoning on the Blood Cholinesterase and Hematological Values in a Dairy Herd. 1985; 26, (11): 350

- 353. Rec #: 20

EcoReference No.: 100325

3. B uschman, L. L. and El Houssaini, K. Evaluation of Insecticidal Control of Hessian Fly and Sawfly in Wheat,

1990. 1992: 308

- 309. Rec #: 30. EcoReference No.: 79776

4. Castillo, L. E.; Martinez, E.; Ruepert, C.; Savage, C.; Gilek, M.; Pinnock, M., and Soli s, E. Water Quality and Macroinvertebrate Community Response Following Pesticide Applications in a Banana Plantation, Limon, Costa Rica. 2006; 367, (1): 418

- 432. Rec #: 40. EcoReference No.: 93203

5. Castro

- Escobar, A.; Kells, J. J., and Penner, D. Evalu ation of a Rapid Method to Detect Terbufos Residue Levels in Corn (Zea mays) Seedlings. 1996; 10, (4): 842

- 846. Rec #: 50. EcoReference No.: 101249

6. Davis, P. M. and Coleman, S. Managing Corn Rootworms: (Coleoptera chrysomelidae) on Dairy Farms:

The Need for a Soil Insecticide. 1997; 90, (1): 205

- 217. Rec #: 60. EcoReference No.: 73930

7. Diehl, K. E. and Stoller, E. W. Effect of Simulated Rainfall, Insecticide Formulation, and Insecticide Application Method on the Interaction Between Nicosulfuron a nd Terbufos in Corn (Zea mays). 1995; 9, (1): 80

- 85. Rec #: 70. EcoReference No.: 101252

8. Forrester, N. W.; Gunning, R. V., and Singh, G. Insecticidal Control and Economic Damage of Sugar

- Cane Wireworm, Agrypnus variabilis (Candeze) in Maize. 1984; 3, (2): 253

- 259. Rec #: 80. EcoReference

No.: 101233

9. Francis, B. M.; Metcalf, R. L., and Hansen, L. G. Toxicity of Organophosphorus Esters to Laying Hens After Oral and Dermal Administration. 1985; 20B, (1): 73

- 95. Rec #: 90. EcoReference No.: 36676

### 121 10. Gentile, J. M.; Gentile, G. J.; Bultman, J.; Sechriest, R.; Wagner, E. D., and Plewa, M. J. An Evaluation of the Genotoxic Properties of Insecticides Following Plant and Animal Activation. 1982; 101, (1): 19

- 29.

Rec #: 100. EcoReference No.: 79052

1 1. Gentile, J. M. and Plewa, M. J. The Maize

- Microbe Bioassay: A Unique Approach to Environmental Mutagenesis. 1983; 5a, (1983): 151

- 165. Rec #: 110. EcoReference No.: 93306

12. Grout, T. G.; Richards, G. I., and Stephen, P. R. Further Non

- target Effec ts of Citrus Pesticides on Euseius addoensis and Euseius citri (Acari: Phytoseiidae). timg@mhs.telkom400.inca.za.1997; 21, (3): 171

- 177. Rec #: 120. EcoReference No.: 64864

13. Hemmer, M. J.; Middaugh, D. P., and Comparetta, V. Comparative Acute Sensitiv ity of Larval Topsmelt, Atherinops affinis, and Inland Silverside, Menidia beryllina, to 11 Chemicals. 1992; 11, (3): 401

- 408 (OECDG Data File). Rec #: 140. EcoReference No.: 13112

14. Hemmer, M. J.; Middaugh, D. P., and Moore, J. C. Effects of Temperatu re and Salinity on Menidia beryllina Embryos Exposed to Terbufos. 1990; 8, (2): 127

- 136. Rec #: 130. EcoReference No.: 7627

15. Holshouser, D. L.; Chandler, J. M., and Smith, H. R. The Influence of Terbufos on the Response of Five Corn (Zea mays) Hybrids to CGA

- 136872. 1991; 5, (1): 165

- 168. Rec #: 150. EcoReference No.: 101257

16. Hooper, M. J.; Brewer, L. W.; Cobb, G. P., and Kendall, R. J. An Integrated Laboratory and Field Approach for Assessing Hazards of Pesticide Exposure to Wildlife. 1990: 271

- 2 83. Rec #: 160. EcoReference

No.: 91436

17. Jayachandran, S. Influence of Insecticides on IAA Metabolism in Paddy Soil. 1979; 48, (12): 538

- 540. Rec #:

170. EcoReference No.: 101299

18. Kapusta, G. and Krausz, R. F. Interaction of Terbufos and Nicosulf uron on Corn (Zea mays). 1992; 6, (4):

999

- 1003. Rec #: 180. EcoReference No.: 101250

19. Koeppe, M. K.; Hirata, C. M.; Brown, H. M.; Kenyon, W. H.; O'Keefe, D. P.; Lau, S. C.; Zimmerman, W. T., and Green, J. M. Basis of Selectivity of the Herbicide Rims ulfuron in Maize. 2000; 66, (3): 170

- 181.

Rec #: 190. EcoReference No.: 64765

20. Kwon, C. S.; Kells, J. J., and Penner, D. Combined Effects of Acetolactate Synthase

- Inhibiting Herbicides with Terbufos and Piperonyl Butoxide on Corn (Zea mays) and Soybe an (Glycine max). 1995; 9, (4): 696

- 702. Rec #: 200. EcoReference No.: 75595

21. Lim, K. P.; Yule, W. N., and Harris, C. R. The Toxicity of Ten Insecticides to Third Stage Grubs of Phyllophaga anxia (Leconte) (Coleoptera: Scarabaeidae). 1980; 61, (2): 5 5

- 60.

Rec #: 210. EcoReference No.: 100602

22. Metcalf, R. L. and Sanborn, J. R. Pesticides and Environmental Quality in Illinois. 1975; 31, (9): 381

- 436.

Rec #: 220. EcoReference No.: 37948

23. Middaugh, D. P.; Fournie, J. W., and Hemmer, M. J. Vert ebral Abnormalities in Juvenile Inland Silversides Menidia beryllina Exposed to Terbufos During Embryogenesis. 1990; 9, (2): 109

- 116. Rec #: 230

EcoReference No.: 11854

24. Morton, C. A.; Harvey, R. G.; Kells, J. J.; Lueschen, W. E., and Fritz, V. A. Eff ect of DPX

- V9360 and Terbufos on Field and Sweet Corn (Zea mays) Under Three Environments. 1991; 5, (1): 130

- 136.

Rec # : 240. EcoReference No.: 101251

### 122 25. Opperman, C. H. and Chang, S. Plant

- Parasitic Nematode Acetylcholinesterase Inhibition by Carba mate and Organophosphate Nematicides. 1990; 22, (4): 481

- 488. Rec #: 250. EcoReference No.: 91868

26. Quistad, G. B.; Fisher, K. J.; Owen, S. C.; Klintenberg, R., and Casida, J. E. Platelet

- Activating Factor Acetylhydrolase: Selective Inhibition by Pot ent n

- Alkyl Methylphosphonofluoridates. 2005; 205, (2): 149

- 156. Rec #: 260. EcoReference No.: 80192

27. Rahman, A. and James, T. K. Enhanced Activity of Nicosulfuron in Combination with Soil

- Applied Insecticides in Corn (Zea mays). 1993; 7, (4): 824

- 829 . Rec #: 270. EcoReference No.: 64240

28. Rovesti, L.; Heinzpeter, E. W.; Tagliente, F., and Deseo, K. V. Compatibility of Pesticides with the Entomopathogenic Nematode Heterorhabditis bacteriophora Poinar (Nematoda: Heterorhabditidae). 1988; 34, (4): 4 62

- 476. Rec #: 280. EcoReference No.: 93075

29. Sasseville, D. N. Pesticide and Nitrogen Interactions and Tomato Nutrition. 1993: 186 p. Rec #: 290

EcoReference No.: 99136

30. Sauls, B. T. Pesticide Risk Mitigation of Avian Wildlife in Iowa Agroecosyst ems. 1999: 104 p. Rec #: 300

EcoReference No.: 93607

31. Simarmata, M. and Penner, D. Protection from Primisulfuron Injury to Corn (Zea mays) and Sorghum (Sorghum bicolor) with Herbicide Safeners. 1993; 7, (1): 174

- 179. Rec #: 310. EcoReference No.:

7375 7

32. Stoltz, R. L. and Matteson, N. A. Sugarbeet Root Maggot Control, 1991. 1992; 17, 285(125F). Rec #: 320

EcoReference No.: 79793

33. Suett, D. L. and Padbury, C. E. Influence of Some New Application Variables on Insecticide Behavior and Availability in Soil. 1981; 11th, (1): 157

- 164. Rec #: 330. EcoReference No.: 96713

34. Takeuchi, S.; Matsuda, T.; Kobayashi, S.; Takahashi, T., and Kojima, H. In Vitro Screening of 200 Pesticides for Agonistic Activity via Mouse Peroxisome Proliferator

- Activated Receptor (PPAR)alpha and PPARgamma and Quantitative Analysis of In Vivo Induction Pathway. 2006; 217, (3): 235

- 244.

Rec #: 340. EcoReference No.: 89206

35. Van Eeden, C. F. Soil Insect Pests of Groundnut in South Africa, and Their Effect on Yi eld and Quality.

1994: 62

- 65. Rec #: 350. EcoReference No.: 89657

36. Waldrop, D. D. and Banks, P. A. Interactions of Herbicides with Insecticides in Soybeans (Glycine max). 1983; 31, 730

- 734. Rec #: 360. EcoReference No.: 41050