# Problem Formulation for the Environmental Fate, Ecological Risk, Endangered Species, and Drinking Water Exposure Assessments in Support of the Registration Review of Methiocarb

CAS Registry Number: 2032-65-7
PC Code: 100501

Prepared by: Melissa Panger, Ph.D., Biologist Cheryl Sutton, Ph.D., Environmental Scientist Reviewed by: Thomas M. Steeger, Ph.D., Senior Biologist Marietta Echeverria, Risk Assessment Process Leader Elizabeth Behl, Branch Chief U. S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division
Environmental Risk Branch IV 1200 Pennsylvania Ave., NW
Mail Code 7507P Washington, DC 20460



### April 6, 2010

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### Table of Contents

1. Purpose....................................................................................................................................... 4
2. Problem Fo rmulation ........................................................................................................ ......... 4 2.1. Nature of Regulatory Action.............................................................................................. . 4
2.2. Previous Assessments ..................................................................................................... .... 5 2.2.1. Ecological Risk Assessments....................................................................................... 5 2.2.2. Drinking Water Exposure Assessments....................................................................... 6
3. Stressor Source and Distribution ........................................................................................... .... 6
3.1. Mechanism of Action...................................................................................................... .... 8 3.2. Overview of Pesticide Use and Usage................................................................................ 8 3.3. Environmental Fate and Transport.................................................................................... 11 3.3.1. Mobility............................................................................................................... ....... 13 3.3.2. Degradation........................................................................................................... 14 3.3.3. Field Dissipation ...................................................................................................... .. 14 3.4. Water Quality............................................................................................................. ... 15 4. Receptors.................................................................................................................................. 16 4.1. Effects to Aquatic Organisms ........................................................................................... 16 4.2. Effects to Terrestrial Organisms ....................................................................................... 18
4.3. Incident Databases Review............................................................................................... 1 9 4.4. Ecosystems Potentially at Risk ......................................................................................... 20 5. Assessment Endpoints ............................................................................................................. 20 6. Conceptual Model.................................................................................................................... 20 6.1. Risk Hypothesis ................................................................................................................ 21 6.2. Conceptual Diagram ......................................................................................................... 21 7. Analysis Plan .............................................................................................................. ............. 23
7.1. Stressors of Concern ......................................................................................................... 24 7.2. Measures of Exposure....................................................................................................... 24
7.3. Measures of Effect ............................................................................................................ 26 7.4. Integration of Exposure and Effects ................................................................................. 27
7.5. Deterministic and Probabilistic Assessment Methods...................................................... 27 7.6. Endangered Species Assessments..................................................................................... 28 7.8. Preliminary Identification of Data Gaps........................................................................... 29

7.8.1. Fate............................................................................................................................. 29
7.8.2. Effects Data for Methiocarb....................................................................................... 30
8. References................................................................................................................................ 35
APPENDIX A. Label Restrictions for Mesurol ® 

### 75% Wettable Powder Aversive Conditioning Egg Treatment............................................................................................................................... 44 APPENDIX B. Toxicity Data for Methiocarb:............................................................................ 45
APPENDIX C. Chemical Names and Stuctures for Methiocarb and its Environmental Degradates..................................................................................................................................... 56
APPENDIX D: Data Call-In Tables. ........................................................................................... 59

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### 1. Purpose

The purpose of this problem formulation is to pr ovide an understanding of what is known about the environmental fate and ecological effects of methiocarb, considering its currently registered
uses. Methiocarb is an N -methyl carbamate registered for use as a molluscicide, avian repellent, insecticide, and acaricide. Th e compound is registered for use around home and flower gardens, ornamentals (including non-beari ng fruit and nut trees), and to reduce predation on the eggs of federally-listed species of bird s. All of the methiocarb products, except for the homeowner products, are classified as Restri cted Use Pesticides (RUP) “due to toxicity to fish, birds and aquatic organisms” (as stat ed on the RUP labels).

This document will provide a plan for analyzing data relevant to methiocarb and for conducting environmental fate, ecological risk, enda ngered species, and drinking water exposure assessments for the registered uses of methio carb. Additionally, this problem formulation is intended to identify data gaps, uncertainties, a nd potential assumptions used to address those uncertainties relative to characterizing the ecological risk associated with the registered uses of
methiocarb.

2. Problem Formulation

2.1. Nature of Regulatory Action

Under the Federal Insecticide, F ungicide, and Rodenticide Act (FIF RA), all pesticid es distributed
or sold in the United States generally must be registered by the Environmental Protection Agency (EPA). In determining whether a pestic ide can be registered in the U.S., the Agency evaluates its safety to non-target species base d on a wide range of environmental and health effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act, and the Agency was mandated to implement a new program for the periodic review of pesticides, i.e

., Registration Review ( http://www.epa.gov/oppsrrd1/registration_review/ ). The Registration Review program is intended to ensure that, as th e ability to assess risk evolves and as policies and practices change, all register ed pesticides continue to meet the statutory standard of no
unreasonable adverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur ov er time. Through the new Registration Review program, the Agency periodically reevaluates pestic ides to make sure that as change occurs, products in the marketplace can be used safely.

As part of the implementation of the new Regist ration Review program purs uant to Section 3(g) of the Federal Insecticide, Fungi cide and Rodenticide Act (FIFRA), the Agency is beginning its
evaluation of methiocarb to determine whether it continues to meet th e FIFRA standard for registration. This problem formulation for the environmental fate, ecological risk, endangered species, and drinking water assessment chapter in support of the Registration Review will be posted in the initial docket which will open the public phase of the review process.

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### 2.2. Previous Assessments

2.2.1. Ecological Risk Assessments

Methiocarb was first registered as a pesticide in the United States in 1972. There were several assessments conducted as part of Emergency Exemption (Section 18) actions during the 1980’s for the use of methiocarb on artichokes (CA), gol f courses (CT), blueberries (OR and WA), and rice (TX and LA).

A Registration Standard for methiocarb was issued in March 1987 [the ecological topical summary was completed in 1986 (USEPA, 1986)]. The Registration Standard summarized available data supporting the registration of pr oducts containing methiocarb used as a bird repellent in corn fields and fru it orchards and for slug, snail, a nd insect control on ornamentals, lawns, turf, and ginseng. A dditionally, the Registration Standa rd required all outdoor and nonresidential uses of methiocarb be classified as Restricted Use Pes ticide due to risks to birds and aquatic organisms, requiring that methiocarb only be applied by tr ained applicators. In 1989 the technical producer of methiocarb at the time (M iles Inc.) cancelled all te rrestrial food uses of methiocarb. The registration standard also stat es that the technical producer dropped its support of all commercial turf and field-grown ornamental uses.

The last ecological risk assessmen t conducted by the Agency for me thiocarb was done as part of the Reregistration Eligibility Decision (RED) for methiocarb in 1994 (USEPA, 1994). The RED addressed the use on ornamentals, ginseng, lawn, turf, and household/domestic outdoor premises. The ecological effects risk assessment for methio carb indicated that the acute and chronic risk levels of concern (LOC) were exceeded for birds (and for reptiles and terrestrial-phase amphibians for which birds serve as surrogate s), the acute risk LOCs were exceeded for mammals and aquatic invertebrate s, and the chronic risk LOC was exceeded for fish (as well as aquatic-phase amphibians for which fish serve as surrogates) for al l outdoor use sites and
formulations.

The following studies were requested at the time of the RED:

161-1 Hydrolysis 163-1 Adsorption-Desorption/Leaching 164-1 Terrestrial Field Dissipation 72-3 (a) Acute Estuarine/marine Fish Toxicity 72-3 (b) Acute Estuarine/marine Mollusk Toxicity 72-3 (c) Acute Estuarine/mari ne Invertebrate Toxicity 72-4 (a) Fish Early Life Stage 72-4 (b) Aquatic Invertebrate Life-Cycle 72-5 Fish Life-Cycle

A fish accumulation study (165-4) was waived becau se methiocarb and its degradates in aquatic systems were assumed to kill fish before residues could accumulate to levels of concern in fish
tissue. This waiver will be re voked as part of the Registration Review process based on current guideline requirements.

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### -6 of 69- 2.2.2. Drinking Water Exposure Assessments

A separate drinking water exposure assessment has not been conducted for methiocarb, nor was a qualitative assessment done as part of the RE D process. Methiocarb was included in the NMethyl Carbamate Cumulative Risk Assessm ent (EPA; revised 9/07). The assessment conducted for Registration Review will consider both groundwater and surface water exposure.

3. Stressor Source and Distribution

Methiocarb is currently registered for use around home and flower gardens, on ornamentals, and to reduce predation on the eggs of federally-listed species. The parent compound degrades in the environment to the major degradates methiocar b phenol (MP), methiocarb sulfoxide (MSO), and methiocarb sulfoxide phenol (MSOP); and to the minor degradates methiocarb sulfone (MSO 2 

### ) and methiocarb sulfone phenol (MSO 2 

### P). Parent methiocarb, MSO and MSO 2 

### are all acetylcholinesterase inhibitors ( http://pesticideinfo.org ). Methiocarb is registered for outdoor uses, creating a potential for exposure to both aq uatic and terrestrial non-target organisms.

For the ecological risk assessment conducted as part of the Regist ration Review process, all of the degradates listed above will be considered and the degradates of concern will be identified. Modeled exposure estimates resulting from methiocarb usage will reflect the predicted
environmental fate of either methiocarb and indivi dual degradates separately or together as total toxic residues (in methiocarb equivalents), depending on the toxicity differential of the compounds for assessed organisms. For the dr inking water assessment, parent methiocarb, MSO, MSO 2 

### , and MP will likely be assessed in additi on to any other degradates identified as degradates of concern. The final determina tion of which degradates will included in the assessment will be made following consulta tion with the OPP Residues of Concern Knowledgebase Subcommittee (ROCKS).

Toxicity data for the methiocarb degradates have not been submitted to the Agency. Toxicity values for aquatic organisms and MSO 2 

### and MSO were estimated using ECOSAR (version 1.00) (see Table 3.1 ). T he structure-activity relationships (SARs) in ECOSAR are used to predict the aquatic toxicity of chemicals based on their sim ilarity of structure to chemicals for which the aquatic toxicity data have been previously measured. The estimated toxicity values for methiocarb sulfone and methiocarb sulfoxide suggest that they are either equitoxic or less toxic than the parent to the aquatic organisms included in the analyses. Some toxicity data for MSO 2 

### , MSO, MSO 2 

### P, and MSOP are available through the European Union’s Pesticide Properties Database (PPDB) ( http://sitem.herts.ac.uk/aeru/footprint/en/index.htm ). The studies from which these endpoints are derived were not available fo r review at this time. Taken at face value, however, the data suggest that the degradates ar e not more toxic than the parent for the taxa considered, with the exception of the acu te toxicity values for earthworms (see Table 3.1 ).

The residues of concern for exposure and risk asse ssment will be reconsidered prior to analysis. In the absence of confirmatory da ta indicating low toxici ty concerns for the major degradates of methiocarb ( i.e ., MP, MSO, MSOP, MSO 2 

### , and MSO 2 

### P), they will be assumed of equal toxicity as the parent.-7 of 69-Table 3.1. Toxicity Data for Methiocarb Degradates (no registrant-submitted toxicity data are available of the degradates).SOURCEMETHIOCARBMETHIOCARBSULFONE (MSO2)METHIOCARBSULFOXIDE (MSO)METHIOCARBSULFONEPHENOL (MSO2P)METHIOCARBSULFOXIDEPHENOL (MSOP)ECOSARAcute Fish (LC50; mg/L)--157.8182.6----Acute Fish (SW) (LC50; mg/L)--0.3950.373----Acute Daphnid (EC50; mg/L)--3.53.4----96-hr Green algae (EC50; mg/L)--> solubility limit> solubility limit----Chronic Fish (SW) (mg/L)--2.22.5----Chronic Daphnid (mg/L)--0.220.23----Chronic Green algae (mg/L)--> solubility limit5262----Chronic Fish (SW) (mg/L)--0.0330.032----PPDB (EU) WEBSITE1Acute oral Rat (LD50; mg/kg-bw)19------>3160Acute oral Avian (LD50; mg/kg-bw)5--------Acute Fish (LC50; mg/L)0.65--6.668.7>106Chronic Fish (NOAEC; mg/L)0.05--------Acute FW Invertebrate (EC50; mg/L)0.008--0.05654157Chronic FW Invertebrate (NOAEC)0.0001--------NV Aquatic Plant (EC50; mg/L)2.2--2.75120>100Acute Honeybees (LD50; μg/bee)0.23--------Acute Earthworms (LC50; mg/kg)1322--78>1000>10001Pesticide Properties Database (PPDB) (http://sitem.herts.ac.uk/aeru/footprint/en/index.htm)

### 3.1. Mechanism of Action

Methiocarb is an N -methyl carbamate molluscicide/avian repellent/insecticide/acaricide. Carbamate pesticides act by inhibiting acetylcholin esterase and reducing the degradation of the neurotransmitter acetylcholine. As a result , intersynaptic concentrations of acetylcholine increase leading to increased firing of the postsynaptic neurons. This may ultimately lead to convulsions, paralysis, and death of an organism exposed to the chemical.

3.2. Overview of Pesticide Use and Usage

Methiocarb was first registered in the U.S. in 1972. Methiocarb is currently registered for use on ornamentals (including non-bearing fruit and nut trees), around home and flower gardens, and to reduce predation on the eggs of Fe derally-listed species of birds. The 1987 registration standard
for methiocarb states that th e technical producer dropped its su pport of all commercial turf and field-grown ornamental uses. Ther e are no turf uses on the current labels. The term ‘field-grown ornamentals’ does not appear on current labels; however, the use of methiocarb products on field-grown ornamentals ca nnot be precluded based on current labe ls. Therefore, we assume that
the use of methiocarb on ornamentals coul d include field-grown ornamentals.

There are currently five methiocarb end-us e products registered in the U.S. (see Table 3.2 ). All of the products contain only one active ingredie nt (methiocarb). All of the products, except for the homeowner product (Mesurol ® 

### 2% Bait), are classified as Rest ricted Use Pesticides (RUP).

TABLE 3.2. Summary of Methiocarb Products Registered in the U.S.

Product Name (EPA Reg. No.) Registrant RUP? 1 Percent
Active Ingredient Use

Mesurol ® 2% Bait (10163-232) Gowan No 2% Around the home (including around building foundations) and flower gardens

Mesurol ® 75 WDG (10163-252) Gowan Yes 75%

Mesurol ® 75-W (10163-231) Gowan Yes 75%

Mesurol Pro ® (10163-228) Gowan Yes 2% Ornamentals

Mesurol ® 75% Wettable Powder Aversive Conditioning Egg Treatment (56228-33) USDA Yes 75% Reduce predation on the eggs of listed bird species

1 RUP = Restricted Use Pesticide



### Methiocarb products include flowab le (wettable powder, water-dispe rsible granule) and granular (bait) formulations. According to the labels, me thiocarb can be applied as a flowable liquid [via ground equipment (including chemigation systems)]. Aerial applications ar e not precluded on the labels; however, based on the use patterns aerial applications are not likely, and, thus, will not be modeled if the registrant indicate s that they will be precluded on the labels. Methiocarb is also
used as a scatter bait on orname ntals and flower gardens and as an injection into bird eggs. According the the Mesurol 75% Wettable Powder Aversive Conditioning Egg treatment label, injected [poisoned] eggs are us ed to condition common ravens ( Corvus corax ), white-necked

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### raves ( C. cryptoleucas ), or the common crow ( C. brachyrhnchos ), collectively referred to as corvid egg predators, not to prey upon eggs of Federally listed threatened or endangered species or eggs of other species designate d to be in need of special protection Methiocarb can be used nationally ( i.e ., there are no geographic restrictions on where it can be used). The maximum single application rates specified on the labels per use range from 0.002 lb a.i./acre (treated eggs, based on calculations from the label) to 0.87 lb a.i./acre (ornamentals , around the home, and flower gardens) (see Table 3.3 ).

The maximum application rates per year specif ied on the labels range from 0.004 lb a.i./acre (treated eggs) to 1.74 lb a.i./a cre (ornamentals, around the home , and flower gardens). The maximum number of applications allowed per year is two. The minimum re-application interval, where specified on the label, is 10 days. The maxi mum single or seasonal a pplication rate is not specified on the Mesurol ® 

### 75 WDG or Mesurol ® 

### 75-W labels. The minimum application interval is not specified on the Mesurol ® 

### 2% Bait, Mesurol Pro ® 

### , or Mesurol ® 

### 75% Wettable Powder Aversive Conditioning Egg Tr eatment labels. Conservative assumptions will be made in
the absence of labeled directi ons. Specifically, a maximum single application rate of 1.5 lb a.i./acre (seasonal maximum of 3 lb a. i./acre) will be assumed for Mesurol ® 

### 75 WDG or
Mesurol ® 

### 75-W based on an estimate for the amount of liquid required to drench soil without causing runoff ( i.e ., 200 gallons/acre, based on a sampling of insecticide labels on which soil drench rates are stipulated). Furthermore, a 3- day minimum application in terval will be assumed if it is not stipul ated on the label.

In the assessment, EFED will consider additional use factors, such as whether the pesticide is used mainly for nursery and greenhouse plants, or for established plantings; how much is used
for insect control and how much for slug/snail control; and whet her there are geographic areas where use is high and/or important.

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### TABLE 3.3. Summary of Methiocarb Application Methods and Rates.

PRODUCT FORMULATION APPLICATION
METHOD USE MAX
SINGLE
APPL RATE (lb a.i./acre) MAX
NUMBER
OF APPL/

YEAR MAX APPL
RATE/
YEAR (lb a.i./acre) MIN APPL
INTERVAL

Flowable

Mesurol® 75

WDG

Mesurol® 75-

W Water soluble bag (wettable powder) Foliar
Drench Chemigation
Ground
Aerial 3 Ornamentals (including non-bearing
fruit and nut trees) Not specified (0.75 lb
a.i./100 gallon; 1.5 lb
a.i./acre
assumed – see text) 2 Not specified (3 lb a.i./acre
assumed – see text) 10 days

Bait

Mesurol® 2%
Bait Around the home; flower garden (not for
use on lawns or turf)

Mesurol Pro® Granule Scatter bait Ornamentals (including non-bearing
fruit and nut trees) 1 lb of product/1000
ft 2 (0.02 lb
a.i./1000 ft 2 = 0.87 lb a.i./acre) 2 1.74 lb
a.i./acre Not specified (3 days assumed)

Treated Eggs
Mesurol 75%
Wettable
Powder
Aversive Conditioning Egg

Treatment 1, 2 Wettable powder Treated raw eggs Reduce corvid egg predation
on listed bird species 0.002 lb
a.i./acre 4 2 0.004 lb
a.i./acre Not specified (3 days assumed)

1 Before using, consult with local, state, and Federal w ildlife authorities to ensure that the use of the product does not present a hazard to threatened or endangered species. Do not apply in areas where eggs treated with the product may be consumed by threatened or endangered species.

2 Only to be used in efforts to condition common ravens ( Corvus corax ), white-necked ravens ( C. cryptoleucas ), or common crows ( C. brachyrhynchos ), collectively referred to as corvid egg predators, not to prey on the eggs of listed species.

3 Aerial applications are not precluded on the current labels, however, based on the use patterns ( i.e

., nursery-grown ornamentals) aerial applications are not likely, and, thus, will not be modeled

4 0.75 g a.i./60 ml = 0.0125 g a.i./ml; 3 ml = 0.0375 g a.i./egg; 20 eggs/acre = 0. 75 g a.i./acre = 0.002 lb
a.i./acre



### For Mesurol ® 

### 75% Wettable Powder Aversive Conditioni ng Egg Treatment which is used as a poison for birds that scavenge nests, there are several precautions stipulated on the label that could reduce non-target mortality. Please see APPENDIX A for a list of the precautions.

National-level usage data are not available for methiocarb, however, usage data are available for the state of California [California Department of Pesticide Regulation (CADPR)]. Based on CADPR data for the three most recent years for which data are available (2005 – 2007), an average of 2005 lb of me thiocarb (including non-residential uses only) were applied each year in California (see Table 3.4 ). The largest use was on nursery /outdoor container for field grown

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### plants representing 71.8% of to tal pounds applied in 2005, but declining to 57.5 and 59.9% of total use in 2006 and 2007, respectively.

Table 3.4. Methiocarb Usage Data (Non-Residen tial Uses Only) for California Based on California Department of Pestic ide Regulation (CADPR) Data.

Use 1 2005

Pounds Applied 2006

Pounds Applied 2007

Pounds Applied

Avocados (All or unspecified)
-- -- 6.00 Grapes
-- 22.50
-- Landscape Maintenance 8.22 17.28 8.96

Lemons 1.50 17.65 4.5 Nursery/Greenhouse Grown Cut Flowers or greens 251.70 262.78 185.30 Nursery/Geenhouse Grown Plants in Containers 417.30 261.32 350.22 Nursery/Greenhouse grown transplanted Propagative Material 2.76 73.20 1.88 Nursery/Outdoor Container/Field Grown Plants 1,742.08 1,028.37 1,056.82 Nursery/Outdoor Grown Transplant/Propagative Material 12.00 17.80 18.19
Oranges (All or Unspecified) 24.76 85.99 133.28

Totals 2,460.32 1,787.89 1,765.89 Prepared: August 26, 2009 Cal DPR Data: http://www.cdpr.ca.gov/docs/pur/purmain.htm

-- indicates no available data.

1 Methiocarb is currently registered for use on ornamentals (including non-bearing fruit and nut trees), around home and flower gardens, and to reduce predation on the eggs of Federally-listed species of birds.



### 3.3. Environmental Fate and Transport
Registrant-submitted data defini ng the physical, chemical, fate and transport characteristics
associated with methiocarb are summarized in Table 3.5 . Environmental degradates from the laboratory studies are listed in Table 3.6 along with their maximum c oncentration and associated sampling intervals.

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### TABLE 3.5. General Chemical and Environm ental Fate Parameters of Methiocarb.

Parameter Value Reference/Comments
Selected Physical-Chemical Parameters

Molecular mass 225.3 Product Chemistry
Vapor pressure (Torr) 2.85 x 10 -7 (20°C)

6.6 x 10 -7 (25°C) Product Chemistry

Water solubility (25°C) 27 mg/L Product Chemistry
Henry’s law constant (20°C; atmm 3 /mole) 1.18 x 10 -9 The Pesticide Manual - World Compendium, 11th ed., British Crop Protection Council (1997)
Octanol-air partition coefficient (K

oa ) No data.
Octanol-water partition coefficient (K ow; 20°C) 2200 Product Chemistry

Bioconcentration

Fish Bioconcentration Factor
No data. Data to be called in based
on 40CFR data requirements.

Mobility
Soil partition coefficient (K d ; Freundlich) No data. Data gap.
Organic carbon-norm alized adsorption coefficients (K

oc ) No data. Data gap.

Persistence
Hydrolysis half-life (25°C) 763 (pH 5) 28.1 (pH7) <1 (pH 9) MRID 40624502

Aqueous photolysis half-life (25°C; days) 128 (reported as equivalent to 66 days in a typical summer growing season in Lexington, KY, 38 N latitude) MRID 40624501 Natural light; pH 5.

Soil photolysis half-life (25°C; days) 53 (reported as equivalent to 21 days in a typical summer growing season in Lexington, KY, 38 N latitude) MRID 40622301 Natural light. Supplemental study (light
and moisture conditions cited as issues). Soil pH

6.6

Aerobic soil metabolism half-life (25°C; days) 17.7 (sandy loam) MRID 41194601 Bi-phasic degradation. Data gap; studies on
additional soils are

necessary.

Anaerobic soil metabolism half-life (25°C; days) 64 (sandy loam) MRID 41194601

Aerobic aquatic metabolism half-life (25°C) No data. Data gap.

Anaerobic aquatic metabolism half-life (25°C) No data. Data gap.

Field Dissipation



### -12 of 69-Parameter Value Reference/Comments

Terrestrial field di ssipation half-life; maximum leaching depth No data. No data. None of the
submitted studies were classified acceptable or supplemental based on current guidelines.



### Table 3.6. Summary of major degradate format ion from degradation of methiocarb in laboratory environmental fate studies.
MAJOR DEGRADATE and MAXIMUM CONCENTRATION (as % of applied; days post-treatment)

STUDY TYPE methiocarb phenol (MP) methiocarb sulfoxide (MSO) methiocarb sulfoxide phenol (MSOP) methiocarb
sulfone (MSO 2 ) methiocarb
sulfone phenol (MSO 2 P) SOURCE

Hydrolysis 46% (day 30; pH 7) 82% (day 3; pH 9) 6% (day 7; pH 5) 10% (0.04 days; pH 7) 4% (0.04 days; pH 9) 4% (day 14; pH 7) 11% (day 1; pH 9) -- -- MRID
40624502

Aqueous Photolysis -- 10.1% 2.7%
-- -- MRID
40624501

Soil Photolysis
-- 23.8 (day 20) 3.7 (day 30)
-- -- MRID
40622301

Aerobic Soil
Metabolism 2% (time 0) 30% (29 days) 18% (64 days) 1% (29-91 days) 9% (91 days) MRID
41194601

Anaerobic Soil

Metabolism 47% (64 days) 24% (time 0; formed during aerobic degrade. phase) 8% (time 0; formed during aerobic degrade. phase) <1% (day 64) <1% (days 15-64) MRID
41194601

Aerobic Aquatic

Metabolism -- -- -- -- -- No Data.

Anaerobic

Aquatic
Metabolism -- -- -- -- -- No Data.



### 3.3.1. Mobility
Methiocarb is not expected to volatilize from soil or water ba sed on its vapor pressure and Henry’s Law Constant ( Table 3.5 ). In contrast to the conclusi ons stated in the Reregistration Evaluation Decision (RED) document for meth iocarb, parent methiocarb and three major degradates (MSO, MSOP, MP) are presumed to be mobile in soil based on their presence in the leachate samples of an aged soil column leaching study (MRID 40342201). A data gap exists for the adsorption/desorption data on parent methiocarb and the majo r degradates MSO, MSOP, and MP. These three degradates were detected, along with parent methiocarb, in the leachate of the aged leaching column study conducted on sa nd, sandy loam and silty loam soils (MRID 40342201). A previously acceptable adsorption/desorption (batch equilibrium) study of the parent compound a single loam soil (Accession N o. 00145802) was reclassified as unacceptable because it was conducted in an aqueous phosphate buffer solution (pH 6) rather than in 0.01 N calcium ion solution as currently required for guideline studies. Several submitted

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### adsorption/desorption or leaching stud ies (Accession #’s 00036494, 00109232, 00144666) were
determined to be not scientif ically valid, and would be clas sified as unacceptable based on current guidelines. An additional adsorption/desorption study (MRID 43617301) submitted in response to data requested in the RED was cl assified as unacceptable due to inadequate experimental methods.

3.3.2. Degradation

Methiocarb hydrolyzes rapidl y at alkaline pHs (pH 9 t 1/2 

### of <1 day), but is st able to hydrolysis at pH 5 (t 1/2 

### of 763 days) and only hydrolyzes slowly at pH 7 (t 1/2 

### of 28 days). The major hydrolytic degradate is MP (46% and 82% of the applied at pH 7 and 9, respectively), with some hydrolysis to MSO (4-10%) and MSOP (4-11%). Methiocarb photolyzes slowly in water and on soil (t 1/2 

### of 128 and 53 days, respectively), and is not expected to be a significant degradation pathway in the environment. The degradates de tected in irradiated samples, MSO and MSOP,
were also detected in dark cont rols. Methiocarb is not expected to be persistent in aerobic or
anaerobic soils in the en vironment, based on respective half- lives of 17.7 days and 64 days in a single sandy loam soil. In aerobic soil, methio carb degrades mainly to MSO (30%) and MSOP (18%), with some degradation (1-9%) to MP, MSO 2 

### and MSO 2 

### P. In anaerobic soil, the major degradates are MP (47%) and MSO (24%), with some degradation to MSOP (8%); both MSO 2 

### and MSO 2 

### P were detected at <1% in anaerobic soil. There are no data available for either aerobic or anaerobic aquatic metabolism.

The degradation of methiocarb in soil is not well defined, as only a single aerobic soil was utilized in the one acceptable study. Add itional submitted studies (Accession #’s 00127159, 00147797, 00145790) were not adequate for use in the risk assessment and would not be classified as acceptable or supplemental ba sed on current guidelines. Based on guideline requirements, data from at least three additiona l aerobic soils are needed to more adequately demonstrate the rate of transformation of methiocarb in soils that are representative of the
environmental conditions where use will occur.

Based on current label uses, data are also need ed for aerobic and anaerobic aquatic metabolism to more fully understand the fate of methiocarb and its degradates in the environment. Note that if all labels were amended to pr eclude field-grown ornamentals, there would be no need for these data. The term ‘field-grown ornamentals’ does no t appear on current labels; however, the use of methiocarb products on field-grow n ornamentals cannot be preclud ed based on current labels. Therefore, we assume that the use of meth iocarb on ornamentals coul d include field-grown ornamentals, and the Data Call-In will include the recommendation for these studies as part of the Registration Review process.

3.3.3. Field Dissipation

The environmental fate of methiocarb and its de gradates in the field is uncertain. Although numerous terrestrial field dissipa tion studies have been submitted, none of them are classified as acceptable based on current guidelines. In general, the studies were deficient due to inadequate analytical methods ( e.g ., analytical method nonspecific for individual compounds); the formation

-14 of 69-

### and decline patterns of the degradates were not addressed; and/or the experimental method was insufficient (e.g., field data were incomplete and the soil was not sampled deep enough to define the extent of leaching). The request for additiona l field dissipation data in the RED was based on uses (turf, lawn) that are no longer on the la bel. Data requirements under 40CFR Section 158.1300 (Subpart N) include a terrestr ial field dissipation study for pesticides with terrestrial and/or residential outdoor uses. Although the pr eviously submitted terrestrial field dissipation studies are not acceptable and do not provide usef ul data, the EFED believes that additional studies would provide only limited information for this kind of use pattern. Thus, while the terrestrial field dissipation study is a data gap, it will not be recommended for inclusion in the Data Call-In as part of the Registration Review process.

3.3.4. Bioaccumulation

The Fish Accumulation data requirement was previously waived. As stated in the RED, “...methiocarb and its degradates in aquatic system s are likely to kill fish before the residues
could accumulate to levels of concern in fish tissues.” However, based on 40 CFR data requirements, the lack of a fish bioconcentrati on study is considered a data gap, as methiocarb has a Kow of >1000 and does not hydrolyze rapidly at pH 5 or 7. Thus, the da ta will be called in as part of the Registration Review process.

3.4. Water Quality

No surface water or groundwater monitoring da ta for methiocarb could be located. Although included as part of the N-Methyl Carbamate Cu mulative Risk Assessment (EPA; revised 9/07), there were no monitoring data included for methio carb. Any available data will be considered at
the time the assessment is conducted.

Methiocarb is not identified as a cause of impairment for any water bodies under section 303(d) of the Clean Water Act (based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_ nation_cy.cause_detail_303d?p_cause_group_id=88

5 , accessed Jan. 26, 2010). In addition, no Total Maximum Daily Loads (TMDL) have been developed for methiocarb (based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_ nation.tmdl_pollutant_de tail?p_pollutant_group_id =885&p_pollutant_group_name=PESTICIDES , accessed Jan. 26, 2010) and there are no aquatic life criteria for methiocarb (bas ed on information provided at http://www.epa.gov/waterscien ce/criteria/aqlife/index.html ). More information on impaired
water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/

.

The Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Im paired Water Body and Other Water Quality Data in OPP’s Registration Review Risk A ssessment and Management Process (see: http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf ), in order to ensure they can be used quantitatively or qual itatively in pesticide risk assessments.

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### 4. Receptors

Consistent with the process described in th e Overview Document (USEPA 2004), the risk assessment for methiocarb relies on a surrogate speci es approach. Toxicity data generated from surrogate test species, which are intended to be representative of br oad taxonomic groups, are used to extrapolate the potential effects on a va riety of species (receptors) included under these taxonomic groupings. The most sensitive endpoints from the available toxicity data for methiocarb will be used to quantify risk.

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the available open literature are used to evaluate the potential direct and indirect effects of methiocarb to aquatic and terrestrial receptors. Th is includes toxicity data on the technical grade active ingredient, degradates, and when available, formulated products ( e.g. , “Six-Pack” studies). The open literature studies are identified th rough EPA’s ECOTOXicology (ECOTOX) database, which employs a literature search engine for lo cating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both sources of data ma y also provide insight into the direct and indirect effects of methiocarb and its degradates on biotic communities from loss of species that are sensitiv e to the chemical and from cha nges in structure and functional
characteristics of the affected communities. A review of the data from ECOTOX will be conducted for evaluation for possible quantitative and/or qualitative incl usion in this risk

assessment.

Toxicity data for the methiocarb degradates have not been submitted to the Agency. Toxicity values for aquatic organisms and MSO 2 

### and MSO were estimated using ECOSAR (version 1.00) (see Table 3.1 ). T he structure-activity relationships (SARs) in ECOSAR are used to predict the aquatic toxicity of chemicals based on their sim ilarity of structure to chemicals for which the aquatic toxicity data have been previously measured. The estimated toxicity values for methiocarb sulfone and methiocarb sulfoxide suggest that they are either equitoxic or less toxic than the parent to the aquatic orga nisms included in the analyses.

A summary of the most sensit ive endpoints representing non-target organisms exposed to methiocarb in aquatic and terrestr ial habitats is provided in Se ctions 4.1 and 4.2, respectively. A summary of ecological incidents associated with methiocarb and a description of ecosystems potentially at risk are provided in Sections 4.3 and 4.4, respectively.

4.1. Effects to Aquatic Organisms

A summary of the most sensitive aquatic toxici ty data for methiocarb from registrant-submitted studies is provided in Table 4.1 . A summary of all submitted ecotoxicity data for methiocarb is provided in Appendix A . Methiocarb is classified as very highly toxic to freshwater fish and
freshwater invertebrates on an acute exposure basis; since freshwater fish serve as a surrogate for aquatic-phase amphibians, methiocarb is consid ered very highly t oxic to aquatic-phase amphibians as well. There are currently no methiocarb toxicity data available for

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### estuarine/marine fish, estuarine/marine invert ebrates, or aquatic pl ants (vascular and nonvascular).

Regarding chronic effects, the only data cu rrently available for methiocarb and aquatic organisms are for freshwater fish ( i.e ., there are currently no chronic data available for estuarine/marine fish, estuarine/marine invert ebrates, or freshwater invertebrates). For freshwater fish, the only available NOAEC is 0.05 mg a.i./L for the rainbow trout ( Oncorhynchus mykiss ) based on clinical signs of in toxication (behavior) (MRID 00155967). Because bluegill sunfish ( Lepomis macrochirus ), and not rainbow trout, are the most sensitive
freshwater fish based on acute e xposure, an acute-to-chr onic (ACR) is used to estimate a chronic NOAEC for the bluegill sunfish. This results in a NOAEC of 0.02 mg a.i./L for bluegill sunfish [rainbow trout acute = 0.436 mg a.i./L; rai nbow trout chronic = 0.05 mg a.i./L; ACR = 0.436/0.05 = 8.72; bluegill sunfish acute = 0.18 mg a. i./L; 0.18/8.72 = 0.02 mg a.i./L). In the rainbow trout study there was increased morta lity and weight reduction at concentrations ≥ 0.20 mg a.i./L. There are currently no chronic data available for freshwater invertebrates.

TABLE 4.1. Summary of the Most Sensitive Endpoints from Submitted Aquatic Toxicity
Studies for Methiocarb.
Species Taxa Represented Toxicity Value MRID # Classification Comment Bluegill sunfish ( Lepomis
macrochirus ) 96-hr LC 50 = 0.18 mg a.i./L 40098001 1 Supplemental Slope = 4.4 (95% CI = 1.9, 6.9)

Bluegill sunfish ( Lepomis
macrochirus ) Freshwater fish and aquatic-phase

amphibians NOAEC = 0.02 mg a.i./L N/A N/A Based on an acute-tochronic ratio using
acute and chronic
data from rainbow
trout and acute data from bluegill sunfish;
based on clinical signs of intoxication (behavior); significant mortality and weight reduction

≥ 0.20 mg a.i./L in the rainbow trout study (MRID 00155967).

96-hr EC 50 = 0.0055 mg a.i./L 40098001 1 Supplemental A slope could not be
calculated Stonefly ( Pteronarcys californica ) Freshwater
invertebrates No chronic data
available N/A N/A N/A

Estuarine/marine fish No data available N/A N/A N/A

Estuarine/marine invertebrates No data available N/A N/A N/A Non-vascular aquatic plants No data available N/A N/A N/A Vascular aquatic plants No data available N/A N/A N/A

1 Per EFED policy, the raw data from this study (Mayer and Ellersieck, 1986; MRID 40098001) were reviewed and were found to be supplemental.



### -17 of 69-

### 4.2. Effects to Terrestrial Organisms

Table 4.2 summarizes the most sensitive terrestrial toxicity endpoints for methiocarb based on an evaluation of submitted studies. There are currently no acceptable acute oral avian studies available for methiocarb. However, there are se veral supplemental studies that provide acute toxicity data on a variet y of bird species (see APPENDIX A ). Methiocarb is classified as very highly toxic to birds and highly toxic to mammals and honey bees on an acute exposure basis. Since birds serve as a surrogate for both terrestri al-phase amphibians and reptiles, methiocarb is considered very highly toxic to terrestrial-phase amphibians and re ptiles as well. In addition to
the acute studies available for birds and mammals (and sub-acute dietary st udies for birds), there
are several field studies and aversion st udies available for birds and mammals (see APPENDIX
A ). There are currently no methiocarb toxic ity data available for terrestrial plants.

For chronic exposure, previous methiocarb asse ssments have reported no reproductive effects in mallard ducks ( Anas platyrhynchos ) tested up to 100 mg a.i./ kg-diet or bobwhite quail ( Colinus virginianus ) tested up to 50 mg a.i./kg-diet. However, a re-evaluation of the bobwhite quail data (MRID 00128119) found reproductive effects ( i.e ., reduced percent of 14-day survivors and reduced egg-shell thickness) at 2 mg a.i./kg-diet, the lowest concentration tested. Therefore, the resulting NOAEC is non-definitive ( i.e ., <2 mg a.i./kg-diet). For mammals, a reproduction study is not available, however, there are data for chronic dietary toxicity (2-year study)(MRIDs 00115226 and 00128723) for the laboratory rat ( Ratus norvegicus ). The chronic endpoint for mammals is a NOAEC of 200 mg/kg-diet (10 mg/ kg/day) based on decreased body weight at the 600 mg a.i./kg-diet level There wa s also increased cholinesterase inhibition in laboratory rats at 200 mg a.i./kg-diet.

TABLE 4.2. Summary of the Most Sensit ive Endpoints from Submitted Terrestrial Toxicity Studies for Methiocarb.

Species Taxa Represented Toxicity Value MRID # Classification Comment

House finch ( Carpodacus

mexicanus ) LD 50 = 2.37 mg/kg-bw 40560001 Supplemental Procedures varied
from test to test but which procedure
used for each test was not provided;
no raw data provided; procedures were
not in accordance with Agency guidelines.

Mallard duck ( Anas platyrhynchos ) LC 50 = 929 mg/kg-diet 0 0022923 Acceptable None

Bobwhite quail ( Colinus virginianus ) Birds, reptiles,
and terrestrialphase amphibians

NOAEC = <2 mg a.i./kg-diet 43313004 Acceptable LOAEC = 2 mg a.i./kg-diet; based on reduced 14-day
survival and reduced egg-shell
thickness.



### -18 of 69-Species Taxa Represented Toxicity Value Classification MRID # Comment

Laboratory rat
( Rattus norvegicus ) LD 50 = 14 mg a.i./kgbw (males) 00083437 Acceptable None

Laboratory rat
( R. norvegicus ) Mammals

NOAEC = 200 mg a.i./kg-diet (10 mg a.i./kg-bw) (based on decreased body weight) 00115226
and

00128723 Acceptable Based on a chronic dietary study; decreased body weight at 600 mg a.i./kg-diet; there
was also
cholinesterase
inhibition at 200 mg a.i./kg-diet; a reproduction study

is not available

Honey bee ( Apis mellifera ) Terrestrial
invertebrates LD 50 = 0.375 μg
a.i./bee 00036935 Acceptable Acute contact

Terrestrial Plants No da ta available N/A N/A N/A



### 4.3. Incident Databases Review

Preliminary reviews of the Ecological Incident Information System (EIIS, version 2.1) and the Avian Incident Monitoring System (AIMS) 1 

### were conducted on December 30, 2009. There are currently no reported wildlife or plant incidents involving methio carb listed in the EIIS. However, the Agency has recently received a report (yet to be en tered into the EIIS) from the
National Wildlife Health Center for an incident involving the death of 30 little brown bats ( Myotis lucifugus ) in July 2009 in Valley County, ID. So me of the bats tested positive for carbofuran (N-methyl carbamat e insecticide) and methiocar b, each at 0.5 micrograms/g. Information on how the bats might have been expos ed to these chemicals is not available.

The AIMS database contains one bird incide nt involving methiocarb (event no. 2012). This incident, which occurred in 1995 in St. Char les County, MO, involved both carbofuran and
methiocarb and was the result of intentional misuse . The incident resulted in the death of three bald eagles ( Haliaeetus leucocephalus ), six chickens ( Gallus gallus domesticus ), one great horned owl ( Bubo virginianus ), and four red-tailed hawks ( Buteo jamaicensis ). Methiocarb and
carbofuran were both classified as having been ‘highly likely’ the cause of the incident.

In addition to the incidents reco rded in EIIS and AIMS, additiona l incidents are reported to the Agency in aggregated incident re ports. Pesticide registrants repor t certain types of incidents to the Agency as aggregate counts of incidents occurring per product per quar ter. Ecological

1 http://www.abcbirds.org/abcprograms/ policy/pesticides/aims/aims/index.cfm



### -19 of 69-

### incidents reported in aggregate re ports include those categorized as ‘minor fish and wildlife’ (WB), ‘minor plant’ (P-B), and ‘other non-target ’ (ONT) incidents. ‘Oth er non-target’ incidents include reports of adverse effect s to insects and other terrestria l invertebrates. No aggregate incident reports have been submitted to the Agency for methiocarb.

Although relatively few incidents involving methiocarb have formally been reported to the Agency, the absence of incident reports cannot be construed as the absence of incidents.

4.4. Ecosystems Potentially at Risk

The ecosystems potentially at risk are often extensive in scope; therefore, it may not be possible to identify specific ecosystems during the deve lopment of a nation-wide ecological risk assessment. However, in general terms, terrest rial ecosystems potentially at risk could include the treated site and immediately adjacent areas th at may receive drift or runoff. Areas adjacent
to the treated site could include cultivated fields, fencerows and he dgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats and other un cultivated areas.

Aquatic ecosystems potentially at risk include wa ter bodies adjacent to, or down stream from, the treated site and could include impounded bodies such as ponds, lakes and reservoirs; or flowing waterways such as streams or rivers; or groundwater. For uses in coasta l areas, aquatic habitat also includes marine ecosystems, including estuaries.

5. Assessment Endpoints

Assessment endpoints represent the ac tual environmental value that is to be protected, defined by an ecological entity (species, community, or ot her entity) and its attr ibute or characteristics (USEPA 1998). For methiocarb, the ecological entities may include the following: birds, mammals, terrestrial-phase amphibian s, reptiles, freshwater fish a nd invertebrates, aquatic-phase amphibians, estuarine/marine fish and invertebrate s, terrestrial plants, terrestrial invertebrates, and aquatic plants. The attributes for each of these entities include growth, reproduction, and
survival.

6. Conceptual Model

For a pesticide to pose an ecological risk, it mu st reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a pesticide moves in the environment from a source to an ecological recepto r. For an ecological pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, an d a feasible route of exposure.

The conceptual model for methiocarb provides a wr itten description and vi sual representation of the predicted relationships betw een methiocarb, potential routes of exposure, a nd the predicted effects for the assessment endpoint. A conceptual model consists of two major components: risk hypothesis and a conceptual diagram (USEPA 1998).

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### Based on the submitted environmental fate data, methiocarb is not expected to volatilize from aerobic soils or alkaline water bodies, but may pers ist in some soils and potentially leach to groundwater and move to surface water through r unoff and spray drift. However, lack of sufficient data add to the uncertainty of the potential for persistence of the pa rent in aerobic soil. The three major degradates, MSO, MSOP, and MP, may also potentially leach to groundwater or move to surface water through runoff and basefl ow. Additional data are still necessary to determine the potential for mobility of these degradat es in soil. However, they were detected in
the leachates of several soils in an aged leaching column study. Methiocarb is degraded by microbially-mediated metabolism in aerobic and an aerobic soils, and by hydrolysis in neutral to alkaline waters. Photolysis of methiocarb may occu r in water or on soil, but so slowly that it is not expected to be a significant environmental fate process. It is not clear whether methiocarb will bioaccumulate in aquatic or terrestri al food chains due to a lack of data.

Based on previous ecological risk assessments for methiocarb, th ere is the potential for acute and/or chronic risk from the exposure of bird s, mammals, fish, and aquatic invertebrates to methiocarb. Because of the potential risk for dire ct effects to taxa (both listed and non-listed) described above, listed species in al l taxa may potentially be affected indirectly due to alterations in their habitat and prey items ( e.g ., food sources, shelter, and areas to reproduce). These preliminary conclusions are used to derive the risk hypothesis a nd conceptual diagram discussed
below.

6.1. Risk Hypothesis

A risk hypothesis describes the predicted re lationship among the stre ssor, exposure, and assessment endpoint response along with the rationale for their selection. For methiocarb and its degradates, the following ecologi cal risk hypothesis is being empl oyed for this ecological risk

assessment:

Based on the application methods, mode of ac tion, fate and transport, and the sensitivity of non-target aquatic and terre strial species, methiocarb and its degradtes have the potential to reduce survival, reproduction, and /or growth in non-target terrestrial and aquatic organisms when used in accordance wi th the current labels. These non-target organisms include federally-listed threaten ed and endangered species as well as nonlisted species.

6.2. Conceptual Diagram

The environmental fate properties of methiocarb indicate that runoff, leaching, spray drift and direct spray represent potential transport mechanisms of the parent compound and its degradates [methiocarb phenol (MP), methiocarb sulfoxide (MSO), methiocarb sulfoxide phenol (MSOP),
methiocarb sulfone MSO 2 

### ) and methiocarb sulfone phenol (MSO 2 

### P)] to aquatic and terrestrial habitats where non-target organisms may be exposed. These transport mechanisms ( i.e ., sources) are depicted in the conceptual models below ( Figures 6.1 and 6.2 ) along with the receptors of concern and the potential attribute changes in the receptors due to exposures to methiocarb and its degradates of potential concern (to be identified when data are available).

-21 of 69-Methiocarb applied to use site 

### Stressor

Source

Receptors

Attribute Change Fish/aquatic-phase amphibians Eggs

Larvae
Juveniles / Adults

Individual organisms
Reduced survival Reduced growth Reduced reproduction Food chain Reduction in algae Reduction in prey Habitat integrity Reduction in primary productivity
Reduced cover Community change Surface water/

Sediment Runoff

Aquatic Animals
Invertebrates
Vertebrates 

### Exposure
Media

Uptake/gills or integument

Ingestion Ingestion Long-range atmospheric

transport

Wet/dry deposition Soil Groundwater

Uptake/gills Spray drift (flowable

only)

or integument

Aquatic Plants

N on-vascular
Vascular Uptake/cell, roots, leaves Riparian plant
terrestrial

exposure pathways see

Figure 6.2



### FIGURE 6.1. Conceptual Model for Methioc arb Effects on Aquatic Organisms. Dotted Lines Indicate Exposure Pathways that H ave a Low Likelihood of Contributing to Ecological Risk.

-22 of 69-Methiocarb applied to use site 

### Stressor

Source

Receptors

Attribute Change Direct application

Birds / Terrestrialphase amphibians / reptiles /

mammals

Terrestrial
invertebrate

Individual organisms
Reduced survival Reduced growth Reduced reproduction Food chain Reduction in prey Habitat integrity Reduction in primary productivity
Reduced cover Terrestrial/riparian plants grasses/forbs, fruit, seeds (trees, shrubs) Runoff

Mammals 

### Exposure
Media Soil

Ingestion Ingestion

Ingestion Ingestion Dermal uptake/Ingestion Long-range atmospheric

transport

Root uptake
Wet/dry deposition

Birds /

Am p hibians Ingestion Spray drift (flowable only)

Community change



### FIGURE 6.2. Conceptual Model for Methi ocarb Effects on Terrestrial Organisms.

7. Analysis Plan

In order to address the risk hypot hesis, the potential for adverse effects on the environment will be estimated. The use, environmental fate, and ecological effects of methiocarb and its degradates [methiocarb phenol (MP), methiocarb sulfoxide (MSO ), methiocarb sulfoxide phenol (MSOP), methiocarb sulfone (MSO 2 

### ) and methiocarb sulfone phenol (MSO 2 

### P)] will be characterized and integrated to assess the risks. Exposure to methiocarb residues will reflect the predicted environmental fate of each compound separa tely or together as total toxic residues (in methiocarb equivalents), depending on the toxicity differential for each of the compounds to the assessed organisms. Risk quotients (RQs) will be derived for methiocarb by dividing estimated environmental concentrations (EEC) by the most sensitive endpoint from the relevant, available toxicity data for methiocarb.

This analysis plan will be re visited and may be revised dependi ng upon a full review of the data available in the open literature and the inform ation submitted by the public in response to the opening of the Registration Review docket.

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### 7.1. Stressors of Concern

The parent compound degrades in the environment mainly to the major degradates methiocarb phenol (MP), methiocarb sulfoxide (MSO), and methiocarb sulfoxide phenol (MSOP), with some additional degradation to the mi nor degradates methiocarb sulfone MSO 2 

### ) and methiocarb sulfone phenol (MSO 2 

### P). Parent methiocarb, MSO and MSO 2 

### are all acetocholinesterase inhibitors and will likely be assessed in th e drinking water assessment along with the major degradate MP. For the ecological risk assessment all of the degradates listed above will be considered. Modeled exposure estimates resu lting from methiocarb usage will reflect the predicted environmental fate of methiocarb and individual degradates separately or together as total toxic residues (in methiocarb equivalents), depending on the toxicity differential for each of the compounds for assessed organisms.

The identification of which degradates constitu te residues of concern for exposure and risk assessment will be reconsidered prior to analysis. In the absence of data indicating low toxicity concerns for the degradates of methiocarb, they w ill be assumed of equal toxicity to that of the parent for the ecological risk assessment.

In its ecological risk assessments, the Agency does not routinely include an evaluation of mixtures of active ingredients, either those mi xtures of multiple activ e ingredients in product formulations or those in the applicator’s tank. In the case of the product formulations of active ingredients (that is, a registered product contai ning more than one active ingredient), each active ingredient is subject to an indi vidual risk assessment for regula tory decision regarding the active ingredient on a particular use site. If eff ects data are available for a formulated product containing more than one active ingredient, the da ta may be used qualitatively or quantitatively in accordance with the Agency’s Overview Document and the Services’ Evaluation Memorandum (USEPA 2004; U SFWS/NMFS 2004).

Available toxicity data for environmental mixtur es of methiocarb with other pesticides will be presented as part of the ecological risk assessmen t. It is expected th at the toxic effect of methiocarb, in combination with other pesticides used in the environmen t, is likely to be a function of many factors including but not necessarily limited to: (1 ) the exposed sp ecies, (2) the co-contaminants in the mixture, (3) the ratio of methiocarb and co-contaminant concentrations, (4) differences in the pattern and duration of exposure among cont aminants, and (5) the
differential effects of other physical/chemical characteristic s of the receiving waters ( e.g. organic matter present in sediment and suspended water). Quantitatively predicting the combined effects
of all these variables on mixture toxicity to any given ta xa with confidence is beyond the capabilities of the available data and methodologies. However, a qualitative discussion of implications of the available pes ticide mixture effects data on the confidence of risk assessment conclusions will be addressed as part of the uncertainty analysis.

7.2. Measures of Exposure

In order to estimate risks of methiocarb exposures in aquatic and terrestrial environments, all exposure modeling and resulting risk conclusion s will be made based on maximum application rates for the currently registered uses ( i.e ., around homes and gardens, ornamentals, and bird

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### repellent) as discussed in Sec tion 5. Measures of exposure for the home owner and ornamental uses are based on aquatic and terrestrial m odels that predict estimated environmental concentrations (EEC) of methiocarb using maxi mum labeled application rates and application methods that have the greatest potential for off-si te transport of the chemical. The models used to predict aquatic EECs in surface water are the Pesticide Root Zone Model coupled with the EXposure Analysis Model System (PRZM/EXAMS). The models used to predict aquatic EECs in groundwater is Screening Concentration in Ground Water (SCI-GROW). The model used to predict terrestrial EECs on food items is T-REX. The model used to derive EECs relevant to terrestrial and wetland plants is TerrPlant. Th ese models are parameterized using relevant reviewed registrant-submitted environmental fate data.

PRZM (v3.12.2, May 2005) and EXAMS (v2.98.4.6, Ap ril 2005) are screening simulation models coupled with the graphical user interf ace, PE (v5.0, November 2006) to generate daily exposures and 1-in-10-year EECs of methiocarb residues that may occur in surface water bodies adjacent to application sites receiving methiocarb through runoff and spray drift. PRZM simulates pesticide application, movement and transformation on an agricultural field and the resultant pesticide loadings to a receiving water body via runoff, erosion, and spray drift. EXAMS simulates the fate of the pesticide and resulting concentrations in the water body. The standard watershed geometry used for ecological pesticide assessments a ssumes application to a 10-hectare agricultural field that drains into an adjacent 1-hectare water body that is 2 meters deep (20,000 m 3 

### volume) with no outlet. The com posite model PRZM/EXAMS is used to estimate screening-level exposure of aquatic orga nisms to methiocarb. The measure of exposure for aquatic species is the 1-in-1 0-year peak or rolling mean concentration. The 1-in-10-year peak is used for estimating acute exposures of di rect effects to aquatic organisms. The 1-in-10- year 60-day mean is used for assessing chronic e xposure to fish and aquatic-phase amphibians. The 1-in-10-year 21-day mean is used for a ssessing aquatic invertebrate chronic exposure.

SCIGROW (Screening Concentration in Ground Water) is a regression model used as a screening tool to estimate pestic ide concentrations found in ground wa ter used as drinking water. SCIGROW was developed by fitting a linear model to groundwater concentrations with the Relative Index of Leaching Potential (RILP) as the independent variable. Groundwater concentrations were taken from 90-day averag e high concentrations from Prospective Ground Water studies; the RILP is a function of aerobic soil metabolis m and the soil-water partition coefficient. The output of SCIG ROW represents the concentrations that might be expected in shallow unconfined aquifers under sandy soils, whic h is representative of the ground water most vulnerable to pesticide contamination likel y to serve as a drinking water source.

To estimate potential exposure to aquatic organisms from the egg treatment it will be assumed that all 20 eggs placed in an acre are someho w washed into a standard 20,000,000-liter farm pond. This is a conservative assumption because it is assumed that all of the pesticide is
available for dissolution. This results in a concentration of 0.045 μg/L (0.002 lb a.i./20,000,000 L).

Exposure estimates for terrestrial an imals that are assumed to be in the target area or in an area exposed to spray drift from the home owner and ornamental uses are derived using the T-REX model (version 1.4.1, 10/08/2008). This model incor porates the Kenaga no mograph, as modified

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### by Fletcher et al. (1994), which is based on a large set of actual fiel d residue data. The upper limit values from the nomograph represent the 95 th 

### percentile of residue values from actual field measurements (Hoerger and Kenaga, 1972). The Fletcher et al. (1994) modifications to the Kenaga nomograph are based on measured field residues from 249 published research papers, including information on 118 species of plants, 1 21 pesticides, and 17 chemical classes. For granular applications, estimated lo adings of pesticide pe r unit area are calculat ed. This approach, which is intended to represent exposure via multi ple routes and not just direct ingestion,
considers observed effects in field studies and relates them to the pesticide applied to surface area. In the absence of data, EFED will assume a foliar dissipation half-life of 35 days. The amount of pesticide per square f oot (relative to the application rate) is calculated using the following assumption: broadcast treatment without incorporation assumes 100% of granules are unincorporated.

To estimate potential exposure to non-target te rrestrial animals from the egg treatment the assessment will assume that non-target birds and mammals of the medium and large size classes from T-REX eat two treated eggs (since they are cach ed in sets of one or two eggs). This would result in the ingestion of 0.0002 lb a.i./animal or 90.7 mg a.i./animal. For example, for a 100 g bird, this would result in a dose-based EEC of 90.7 mg a. i./0.1 kg-bw = 907 mg a.i./kg-bw.

If terrestrial plant toxicity data are availabl e, EECs for terrestrial pl ants inhabiting dry and wetland areas are derived for the home owner and ornamental uses using TerrPlant (version 1.2.2, 12/26/2006). This model uses estimates of pe sticides in runoff and in spray drift to calculate EECs. EECs are based upon solubilit y, application rate and minimum incorporation depth. The AgDRIFT spray drift model (v2.01; May 2001) is used to assess exposures of organisms to methiocarb deposited on te rrestrial habitats by spray drift.

7.3. Measures of Effect

Ecological effects data are used as measures of di rect and indirect effects to biological receptors. Data are obtained from registrant-submitted studies or from literature studies identified by ECOTOX. The ECOTOX database pr ovides more ecological effects da ta in an attempt to bridge existing data gaps. ECOTOX is a source for locati ng single chemical toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and Development, and the National
Health and Environmental Effects Research Laboratory's Mid-Continent Ecology Division.

Information on the potential effect s of methiocarb on non-target anim als is also collected from the Ecological Incident Information System (EIIS). The EIIS is a database containing adverse effect (typically mortality) reports on non-targ et organisms where such effects have been associated with the use of pesticides. Incidents reported in the aggregate incident reports and the Avian Incident Monitoring System (AIMS) will also be searched. AIMS is a database administered by the American Bird Conservanc y (it was partially funded by the EPA). It contains publicly available data on repor ted avian incidents involving pesticides (http://www.abcbirds.org/abcprograms/po licy/pesticides/aims/aims/index.cfm).

Where available, sub-lethal effects observed in both registrant-submitted and open literature studies will be evaluated qualitatively. Such effects may include behavioral changes ( e.g. ,

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### lethargy and changes in colora tion). Quantitative assessments of risks, though, are limited to those endpoints that can be di rectly linked to the Agency’s assessment endpoints of impaired survival, growth and reproduction.

The assessment of risk for direct effects to non-target organisms makes the assumption that toxicity of methiocarb to birds is similar to te rrestrial-phase amphibians and reptiles. The same assumption is made for fish and aquatic-phase amphibians.

The acute measures of effect used fo r animals in this assessment are the LD 50 

### , LC 50 

### and EC 50



### . LD stands for "Lethal Dose", and LD 50 

### is the amount of a material, given all at once, that is
estimated to cause the death of 50% of the test organisms. LC st ands for “Lethal Concentration”
and LC 50 

### is the concentration of a chemical that is estimated to kill 50% of the test organisms.
EC stands for “Effective Concentration” and the EC 50 

### is the concentration of a chemical that is estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic measures of exposure for listed and non-lis ted animals are the NOAEL/NOAEC and NOEC.
NOAEL stands for “No Observed-Adverse-Effect-Level ” and refers to the hi ghest tested dose of a substance that has been reported to have no harm ful (adverse) effects on test organisms. The NOAEC ( i.e. , “No-Observed-Adverse-Effect-Concentration” ) is the highest test concentration at
which none of the observed effects were statistically different fr om the control. The NOEC is
the No-Observed-Effects-Concentration. Fo r non-listed plants, only acute exposures are assessed ( i.e. , EC 25 

### for terrestrial plants and EC 50 

### for aquatic plants); for listed plants either the

NOAEC or EC 05 

### is used.

7.4. Integration of Exposure and Effects

Risk characterization is the integration of e xposure and ecological effects characterization to determine the potential ecological risk from th e use of methiocarb and the likelihood of direct
and indirect effects to no n-target organisms in aquatic and terr estrial habitats. The exposure and toxicity effects data are integrated in order to evaluate the risks of a dverse ecological effects on non-target species. For the asse ssment of methiocarb risks, the risk quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are divided by acute and chronic toxicity values. The resulting RQ s are then compared to the Agen cy’s Levels of Concern (LOC) (USEPA 2004). These criteria are used to indi cate when methiocarb’s use, as directed on the labels, has the potential to cause adverse direct or indirect effect s to non-target organisms. In addition, incident data from EIIS, aggregate incide nt reports, and AIMS will be considered as part of the risk characterization.

7.5. Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the deterministic point-estimate based approach described in th e risk assessment. Depending on the risk manager’s need for additional information regarding risk, an effort will be made to further qualitatively describe risk using probabilistic tools that the Agency has developed. These tools have been reviewed by FIFRA Scientific Advisory Panels ( http://www.epa.gov/sc ipoly/sap/index.htm ) and have been deemed as appropriate means of refining asse ssments where deterministic approaches have
identified risks.

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### 7.6. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to federally-listed threatened and/or endangere d (listed) species from registered uses of methiocarb. This assessm ent will be conducted in accordance with the Overview Document (USEPA 2004), provisi ons of the ESA, and the Services’ Endangered Species Consultation Handbook (USFWS/NMFS 1998).

The assessment of effects associat ed with the registration of me thiocarb is based on an action
area. The action area is considered to be the ar ea directly or indirectly affected by the federal action, as indicated by the exceedance of Agency Le vels of Concern (LOCs) used to evaluate
direct or indirect e ffects. In the case of a nati onwide risk assessment conducted under Registration Review, the action area will encompass the entire U.S. and its territories. The purpose of defining the action area as the entire U.S. and its territories is to ensure that the initial area of consideration encompasses all areas wher e the pesticide may be used now and in the future, including the potential for off-site tran sport via spray drift and downstream dilution. Additionally, the concept of a na tionwide action area takes into acc ount the potential for direct and indirect effects and any poten tial modification to critical ha bitat based on ecological effect measures associated with reduction in survival, growth, and reproduction, as well as the full suite
of sublethal effects available in the effects literature.

It is important to note that the nationwide action area does not imply that di rect and/or indirect
effects and/or critical habitat modification are expected to or are likely to occur over the full extent of the action area, but rath er to identify all listed specie s and critical habitat that may potentially be affected by the action. The Agency will use more rigorous analysis including
consideration of available land c over data, toxicity data, and exposure information to determine areas where individual listed spec ies and designated critical habita t may be affected or modified via endpoints associated with reduced survival, growth, or reproduction.

7.7. Drinking Water Assessment

Methiocarb is currently registered on non- food commodities only. The Drinking Water Exposure Assessment (DWA) will potentially include methiocarb and the degradates methiocarb sulfoxide (MSO), methiocarb sulfoxide phenol (MSOP), methiocarb sulfone (MSO 2 

### ) and methiocarb phenol (MP). These degradates may be mobile, and MSO and MSO 2 

### are cholinesterase inhibitors as is the parent compound. The final determination of which degradates
will included in the assessment will be made fo llowing consultation with the OPP Residues of Concern Knowledgebase S ubcommittee (ROCKS).

The drinking water assessment will incorporate model estimates of methiocarb residues of concern in both surface water and groundwater. Concentrations of methiocarb residues of
concern in surface water will be estimate d using PRZM/EXAMS (see description in Section
7.2 ). Groundwater exposure estimates for methiocarb residues of concern will be estimated using the Screening Concentration in Ground Water (SCI-G ROW) model (v.2.3, July 2003) followed by a higher tier model if necessary. Th e drinking water assessment will also include a summary of available surface water and groundwat er monitoring data. Because methiocarb is

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### included in the Common Assessment Group for th e N-methyl carbamate cumulative, potential exposure to methiocarb in drinking water wi ll be considered in that assessment.

7.8. Preliminary Identification of Data Gaps

7.8.1. Fate

The studies submitted to fulfill environmental fa te data requirements for methiocarb are not sufficient for exposure assessment. There is on ly a single aerobic soil metabolism half-life, whereas OPPTS guidelines require that data from at least three soil types be submitted in
addition to the initial soil from which kinetic da ta and degradate data ar e obtained. No aquatic metabolism studies have been submitted. Adsorption/desorption data are necessary for the parent compound and the degradates MP, MSO, and MSOP. Submission of environmental chemistry methods in water and soil, and an associ ated independent laborato ry validation is also requested in order to support enforcement and m onitoring purposes at the Federal, state, and local levels. A fish bioconcentration study, whic h was previously waived, will be required as part of Registration Review based on the K
ow 

### (2200) and hydrolysis half- lives of >5 days at pH 5 and 7. Draft Data Call-In (DCI) tabl es for these data are provided in APPENDIX C

.

Although the previously submitted terrestrial fiel d dissipation studies are not acceptable and do not provide useful data, the EF ED believes that additional studi es would provide only limited information for this kind of use pattern. Thus, while the terrestrial field diss ipation study is a data gap, it will not be recommended for inclusion in the Data Call-In as part of the Registration Review process.

The requirement for the aquatic metabolism data is based on 40CFR Section 158.1300 (Subpart N) data requirements for pesticides with terrestrial uses. Note that if all labels were amended to preclude field-grown ornamentals, there woul d be no need for these data, as strictly
residential/outdoor uses do not require aquatic metabolism da ta. The term ‘field-grown ornamentals’ does not appear on current labels; however, the use of methiocarb products on field-grown ornamentals ca nnot be precluded based on current labe ls. Therefore, we assume that
the use of methiocarb on ornamentals could include field-grown ornamentals, which is a
terrestrial use.

Table 7.1 identifies studies by MRID that offer data for each guideline requirement, as well as study classifications and whether or not additi onal data are needed in order to support the Registration Review risk assessment ( i.e. , whether there is a data gap).

TABLE 7.1. Environmental Fate Da ta Requirement Table for Methiocarb.

OPPTS
Guideline Data Requirement Submitted
Studies (MRID) Classification Data Gap? Comments

835.2120 Hydrolysis MRID
40624502 Acceptable No

835.2240 Aqueous photolysis MRID
40624501 Acceptable No Natural light; pH 5.



### -29 of 69-OPPTS
Guideline Data Requirement Submitted Data Classification Comments Studies Gap? (MRID)

835.2410 Soil photolysis MRID
40622301 Supplemental No Natural light. Supplemental study (light and moisture conditions cited as issues). Soil pH 6.6.

835.4100 Aerobic soil
metabolism MRID
41194601 Acceptable Yes Data from at least three additional soils, representative of inte nded use areas, are required.

835.4200 Anaerobic soil
metabolism MRID
41194601 Acceptable No

835.4300 Aerobic aquatic
metabolism No data Yes Study required for pesticides with terrestrial uses. Study would not berequired if label precludes use on fieldgrown ornamentals.

835.4400 Anaerobic aquatic
metabolism No data Yes Study required for pesticides with terrestrial uses. Study would not berequired if label precludes use on fieldgrown ornamentals.

00145802 Not acceptable 835.1230
835.1240 Adsorption/ desorption and leaching 40342201 Not acceptable Yes Analytical methods were inadequate. Studies are needed for the parent, MP,
MSO and MSOP.

835.1410 Laboratory volatility No data No Not required.

Terrestrial field

dissipation 40994801 Not Acceptable No None of the ten field studies are adequate based on current data requirements. However, additional studies would provide only limited information for this kind of use pattern. 835.6100

Analytical method
in soil No data Yes Required study.

835.6200 Analytical method
in water No data Yes Required study.

850.1730 Fish
bioconcentration No data.

Yes Data are required for this compound
based on the K

ow (2200) and hydrolysis half-lives of >5 days at pH 5 and 7.



### 7.8.2. Effects Data for Methiocarb

Although many submissions have been made to pr ovide data on the eff ects of methiocarb to aquatic and terrestrial organisms, data gaps still exist ( Tables 7.2-7.4 ). Data gaps include the following: avian acute oral toxi city, avian reproduction, early-lif e stage estuarine/marine fish toxicity, estuarine/marine fish acute toxicity, estuarine/marine invertebrate acute toxicity, estuarine/marine invertebrate (mollusk) acute toxicity, freshwater fish early life stage, estuarine/marine early life stage, freshwater invert ebrate life-cycle, estuar ine/marine invertebrate life-cycle, terrestrial plant, a nd aquatic plant toxicity studies. These data gaps are discussed
below.

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### TABLE 7.2. Available Ecologi cal Effects Data for Terrestrial Animals Exposed to Methiocarb and Remaining Data Gaps.

Guideline Description MRID/
Accession Classification Data Gap? Comments

Avian oral toxicity (passerine) 40560001 Supplemental Yes 1 850.2100

Avian oral toxicity (upland game species) 00036482 Supplemental Yes 1

Avian dietary toxicity (waterfowl) 00022923 Acceptable No

850.2200

Avian dietary toxicity (upland game species) 00022923 Acceptable No 1 Acute oral toxicity data are required for a passerine and a waterfowl or upland game species under 40 CFR Part 158. Acceptable avian acute oral toxicity data are not available for any bird species. Therefore, this is identified as a data gap. However, since supplemental data are available for a variety of species, EFED does not recommend requesting these
data at this time.

. Avian reproduction (waterfowl) 128120 Acceptable No

850.2300 Avian reproduction (upland game species) 128119 Supplemental Yes 2 2 Avian reproduction data are required for a waterfowl and an upland game species under
40 CFR Part 158. A definitive
NOAEC has not been established for birds, because
the lowest dose tested resulted in effects. Therefore, the specific risk to birds from chronic exposure to
methiocarb is unknown and EFED recommends requesting these data (for an upland game species).

850.3020 Honeybee acute contact toxicity 00036935 Acceptable No

850.3030 Honey bee toxicity of residues on foliage None Not applicable Yes 3 3 Data on honey bee toxicity of residues on foliage are required when the acute honey
bee contact LD 50 <11 μg/bee and the use pattern(s) indicate(s) that honey bees may be exposed to the pesticide



### -31 of 69-

### TABLE 7.3. Available Ecologica l Effects Data for Aquatic An imals Exposed to Methiocarb and Remaining Data Gaps.

Guideline Description MRID/
Accession Classification Data Gap? comments

Freshwater fish –

Acute toxicity (coldwater species) 150628 Acceptable No 850.1075

Freshwater fish – Acute toxicity (warmwater species) 150628 Acceptable No

850.1075 Saltwater fish – Acute toxicity None Not applicable Yes 1

850.1010 Freshwater
invertebrates – Acute toxicity 127638 Acceptable No

850.1025 Saltwater invertebrates

– Acute toxicity (oyster shell deposition) None Not applicable Yes 1 1 Acute toxicity data on a saltwater fish, mollusk, and a
saltwater invertebrate are required under 40 CFR Part
158. Since these data are not currently available, EFED recommends requesting these
data at this time.

850.1035, 850.1045,

or 850.1055 Saltwater invertebrates

– Acute toxicity (mysid,

penaeid, or bivalve) None Not applicable Yes 1

850.1300 Freshwater
invertebrate – life cycle test None Not applicable Yes 2

850.1350 Saltwater invertebrates

– life cycle test None Not applicable Yes 2

850.1400 Freshwater fish – early life stage test (freshwater) 00155967 Supplemental Yes 3

850.1400 Fish – early life stage test (saltwater) None Not applicable Yes 2 2 Since the LC 50 values for the
most sensitive fish and invertebrate species tested are < 1 mg/L, an estuarine/marine invertebrate life cycle test and an estuarine/marine fish early life stage test are required
under the new 40 CFR Part 158. Therefore, these are identified as a data gaps and EFED recommends requesting
these data.

3 Chronic toxicity data from the most acutely sensitive species ( i.e ., bluegill sunfish) is currently not available. Therefore, this is identified as a data gap.



### -32 of 69-

### TABLE 7.4. Available Ecologi cal Effects Data for Plants Exposed to Methiocarb and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? comments

850.4100 Terrestrial Plant toxicity: Tier I seedling

emergence None Not applicable Yes 1

850.4225 Terrestrial Plant toxicity: Tier II seedling

emergence None Not applicable No 2

850.4150 Terrestrial Plant toxicity: Tier I vegetative vigor None Not applicable Yes 1

850.4250 Terrestrial Plant toxicity: Tier II vegetative vigor None Not applicable No 2

850.5400 Aquatic Plant Growth: algae None Not applicable Yes 1

850.4400 Aquatic Plant Growth: vascular plants None Not applicable Yes 1 1 Tier I vegetative vigor and seedling emergence studies and aquatic plant studies (both vascular and non-vascular) are required under 40 CFR Part
158. These data are not currently available; therefore, EFED recommends requesting
these data.

2 Tier II studies may be required depending on the results of the Tier I plant
studies.



### Avian Acute Oral Toxicity

Acute oral toxicity data (850.2100) are required for a passerine and a waterfowl or upland game species under 40 CFR Part 158. Acceptable guide line avian acute oral toxicity data are not available for any bird species for methiocarb. Th erefore, this is iden tified as a data gap. However, since supplemental nonguideline data are available for a variety of species (including passerines, upland game species, and waterfowl – see APPENDIX C ), EFED does not recommend requesting these data at this time.

Avian Reproduction Toxicity

Under the 40 CFR Part 158 (July 1, 2009) avian re production data are required on waterfowl and upland game species (OPPTS 850.2300). Currently acceptable data for methiocarb are only available for waterfowl. The chronic toxicity data available for birds indicate that bobwhite quail (NOAEC <2 mg a.i./kg-diet based on reduced survival of 14-day old birds and reduced eggshell thickness) (MRID 128119) are more sensitive to methiocarb than mallard duck (NOAEC = 100 mg a.i./kg-diet, the highest concentration te sted) (MRID 128120). Since a definitive NOAEC for bobwhite quails is not available (the lowe st dose tested resulted in effects), the specific risk to birds from chronic exposure to methiocarb is unknown. Therefore, in order to complete the risk assessment, additiona l data are needed. In the absence of such data, risks to both listed and non-listed bird species wi ll be presumed in the risk assessment conducted for Registration Review.

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### Honey Bee Toxicity of Residues on Foliage

Under the 40 CFR Part 158 (July 1, 2009) data on honey bee toxicity of residues on foliage are required (OPPTS 850.3030) when the acute honey bee contact LD 50 

### <11 μg/bee and the use pattern(s) indicate(s) that honey bees may be exposed to the pe sticide. The acute contact LD 50 

### for methiocarb is 0.375 μg a.i./bee (MRID 00036935). Furthermore, the use of foliar methiocarb on ornamentals (some of which may be flowering) represents a route of potential exposure to honey bees. Therefore, in order to complete the risk assessment, additiona l data are needed. In the absence of such data, risks to honey bees will be presumed in the risk assessment conducted for Registration Review.

Acute Estuarine/marine Fish and Invertebrate Toxicity

Acute toxicity data on a saltwater fish (850.1075), mollusk (850.1025), and a saltwater invertebrate (850.1035, 850.1045, or 850.1055) are require d under 40 CFR Part 158. Since these data are not currently available, EFED recommends requesting these data at this time. In the absence of such data, risks to both listed a nd non-listed estuarine/marine species will be presumed in the risk assessment conducted for Registration Review.

Chronic Toxicity Studie s with Aquatic Animals

Acceptable chronic toxicity data for methiocarb are not availabl e for estuarine/marine fish (850.1400), freshwater invertebra tes (850.1300) or estuarine/mari ne invertebrates (850.1350). Furthermore, a supplemental study is available for freshwater fish, but not for the most acutely sensitive species ( i.e ., bluegill sunfish). Since the LC 50 

### values for the most sensitive fish and invertebrate species tested are < 1 mg/L, estuarin e/marine and freshwater invertebrate life cycle
studies and estuarine/marine and freshwater fish early life stag e studies are required under the current 40 CFR Part 158. Therefore, these are id entified as a data gaps. In the absence of chronic methiocarb toxicity data for fish, an acute-to-chronic ratio (ACR) using rainbow trout data will be used to extrapolat e a chronic endpoint for bluegill sunf ish and estuarine/marine fish.
In the absence of chronic toxi city data for estuarine/marine invertebrates, an ACR using freshwater invertebrate data (o nce available) will be used ex trapolate a chronic endpoint for
estuarine/marine invertebrates. If chronic toxici ty for aquatic invertebrate s is not available, the Agency will presume risks to aquatic inve rtebrates from the use of methiocarb.

Terrestrial Plant Studies

Terrestrial plant toxicity st udies [both seedling emergen ce (850.4100) and vegetative vigor (850.4150)] and associated risk analysis of plants are required for registrati on of pesticides with outdoor uses (40 CFR Part 158). Tier II studies (850.4225 and 850.4250) may be required depending on the results of the Tier I plant studies. If toxicity da ta for terrestrial plants are not submitted for methiocarb, EFED will presume risk for terrestrial plants.

Vascular and Non-vascular Aquatic Plant Studies

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### Aquatic plant toxicity studies and associated risk analysis of plants ar e required for registration of pesticides with out door uses (40 CFR Part 158). Toxici ty data for both vascular and nonvascular aquatic plants (Tier I, OPPTS Guidelines 850.4400 and 850.5400) are required but are
not available for methiocarb. Ther efore, EFED recommends request ing toxicity data on vascular and non-vascular aquatic plants for methiocarb. If toxicity data for aquatic plants are not submitted for methiocarb, EFED will presume risk for aquatic plants.

8. References

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the EPA food-chain (Kenaga) nomogram, an inst rument for estimating pesticide residues on plants. Environ. Tox. Chem.

13:1383-1391.

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

USEPA, 1986. Methiocarb Registration Standard; Environmental Effects Topical; Summary. U.S. Environmental Protection Agency, Office of Pesticide Progra ms, Washington, DC. December 1, 1986.

USEPA, 1994. Reregistration Eligibility Decision Docume nt. U.S. Environmental Protection Agency, Office of Pesticide Programs, Washington, DC. March 30, 1994. http://www.epa.gov/oppsrrd1/REDs/old_reds/methiocarb.pdf

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

USEPA. 2002. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version II. US Environmental Protection Agency, Washington DC. Online at: http://www.epa.gov/oppefed1/models water/input_guidance2_28_02.htm.

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. U.S. Environmental Protection Agency, Of fice of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004.

USEPA. 2009. 40 CFR Part 158. Pesticides; Data Requirements for Conventional Chemicals: Final Rule. 72 FR 60934. July 1, 2009.

USEPA. 2007. ECOTOXicology Database. Office of Research and Development National Health and Environmental Effects Research Laboratory’s (NHEERL’s) Mid-Continent Ecology Division (MED). http://cfpub.epa.gov/ecotox/

.

U.S. Fish and Wildlife Service (USFWS) and National Ma rine Fisheries Service (NMFS). 1998. Endangered Species Consultation Handbook: Procedures for Conducting Consultation and Conference Activities Under Section 7 of the Endangered Species Act. Final Draft. March 1998.

SUBMITTED ENVIRONMEN TAL FATE STUDIES:



### -35 of 69-

### Abdel-Wahab, A.; Kuhr, R.; Casida, J. (1966) Fate of C14-carbonyl- labeled aryl methylcarbamate insecticide chemicals in and on bean plants. J. Agr. Food Chem. 14(3):290- 297. (Submitter 18274; also In unpublished subm ission received Jul 15, 1976 under 3125-EX135; submitted by Mobay Chemical Cor p., Kansas City, MO; CDL:227756-E)

Atwell, S.H.; Gronberg, R.R. (1975) Photod ecomposition of Bay NTN 9306-Ring-UL-14C: Report No. 44844. (Unpublished study received Nov 1, 1975 under 3125-EX-132; submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:095559-H)

Atwell, S.; Murphy, J. (1978) Soil Absorption a nd Desorption of [Carbon 14] Mesurol: Mobay report No. 66145. Unpublished study prepared by Mobay Chemical Corp. 14 p.

Becker, B.D.; Schiller, L.K. (1981) ?Residue of ^(R)IMesurol in Soil|: Report No. 69230. (Unpublished study received May 29, 1981 under 3125-288; prepared in cooperation with Everglades Laboratories, Inc., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:070111-E)

Becker, B.D.; Schiller, L.K. (1981) ?^(R)IM esurol Residue in Soil|: Report No. 69231. (Unpublished study received May 29, 1981 un- de r 3125-288; prepared in cooperation with Everglades Laborato- ries, Inc., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:070111-F)

Becker, B.D.; Schiller, L.K. (1981) ?^(R)IM esurol Residue in Soil|: Report No. 69239. (Unpublished study received May 29, 1981 un- de r 3125-288; prepared in cooperation with Everglades Laborato- ries, Inc., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:070111-J)

Borderland Products Inc. (1986) Residue Data on Methiocarb in Paddy Canal and Receiving Waters. Unpublished study prepared in cooperati on with Craven Laboratories, Inc. and Morse Laborato- ries, Inc. 71 p.

Borderland Products Inc. (1986) Aquatic Field Dissipation in Water. Unpublished compilation prepared in cooperation with Cr aven Lab- oratories Inc. and Morse Laboratories Inc. 74 p.

Borderland Products Inc. (1986) Aquatic Fiel d Dissipation in Soil. Unpublished compilation prepared in cooperation with Mors e Lab- oratories, Inc. 33 p.

Chemagro Corporation (1973) Chemagro Corpor ation Soil Persisten ce Study: Report No. 26880. (Unpublished study including report nos. 26881 and 26883, received Mar 26, 1975 under 3125- EX-119; submitted by Mobay Chemical Co rp., Kansas City, Mo.; CDL: 094390-BC)

Chemagro Corporation (1973) Chemagro Division of Baychem Corpora- tion Soil Persistance Study: ?^(R)IMesurol|: Repor t No. 38948. (Unpublished study in cluding report nos. 38949 and 38950, re- ceived Mar 26, 1975 under 5F1607; prepar ed in cooperation with Agricultural Consultants, Inc., submitted by Mobay Chemi cal Corp., Kansas City, Mo.; CDL:094391-AF)

-36 of 69-

### Chemagro Corp. (1970) Chemagro Corporat ion Soil Persistence Study: Report No. 26880. (Unpublished study received Sep 8, 1971 under 3125-234; CDL:119895-C)

Church, D.D. (1970) Bay 37344--Runoff, Leachi ng, and Water Stabili- ty: Report No. 26894. (Unpublished study received Jul 2, 1975 under 6F1652; submitted by Chemagro Corp., Kansas City, Mo.; CDL:094636-D)

Church, D.D.; Flint, D.R. (1971) The Fate of (R)Mesurol (4-(Met h- ylthic)-3,5-xylyl methylcarbamate) in Soil: Report No. 29591. (Unpublished study received Mar 26, 1975 under 5F1607; prepared in cooperation with Agricu ltural Consultants Laboratory, sub- mitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-K)

Church, D.D.; Flint, D.R. (1971) The Fate of ^(R)IMesurol ?4-(M eth- ylthio)-3,5-xylyl methylcarbamate| in Soil: Report No. 29591. (Unpublished study received Jul 2, 1975 under 6F1652; submitted by Chemagro Corp., Kansas City, Mo.; CDL:094636-I)

Crosby, D.; Leitis, E.; Winterlin, W. (1964) The Photodecomposition of Carbamate Insecticides: ?Submitter| 16458. (Presented at the 148th National Me eting of the American Chemical Society; Aug 31, 1964, Chicago, IL; unpublished study recei ved Jun 2, 1975 under 2F1244; prepared by Univ. of California--Davis, Agri- cultural Toxicology and Residue Research Laboratory, submitted by Mobay Chemical Corp., Kansas City, MO; CDL:094546-C)

Crosby, D.; Leitis, E.; Winterlin, W. (1965) Photodecomposition of carbamate insecticides. Agricultural and Food Chemistry 13 (3):204-207. (Also In unpublished submission received Apr 12, 1968 under 464-EX-30; submitted by Dow Chemical U.S.A., MIdland, MI; CDL:123614-A)

Flint, D.R.; Shaw, H.R., II (1974) The Mobility of ^(R)IMesurol Residues in Soil Runoff Water and the Degradation of Mesurol-14C in Pond Water: Report No. 39258. (Unpublished study received Mar 26, 1975 under 5F1607; prepared in c ooperation with Agri- cultural Consultants, Inc., submitted by Mobay Chemical Co rp., Kansas City, Mo.; CDL:094391-AH)

Houseworth, L.D.; Tweedy, B.G. (1974) Phot odecomposition of ^(R)IMesurol-ring-1-14C: Report No. 39895. (Unpublished study received Mar 26, 1975 under 5F1607; prepared in cooperation with Univ. of Missouri, Dept. of Plant Pathology, submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-AL)

Houseworth, L.D.; Tweedy, B.G. (1974) Phot odecomposition of ^(R)IMesurol-ring-1-14C: Report No. 39895. (Unpublished study received Mar 26, 1975 under 5F1607; prepared in cooperation with Univ. of Missouri, Dept. of Plant Pathology, submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-AL)

Houseworth, L.D.; Tweedy, B.G. (1974) Parent Leaching Studies for ^(R)IMesurol: Report No. 39937. (Unpublished study received Mar 26, 1975 under 5F1607; prepared in cooperation with Univ. of Missouri, Dept. of Plant Pathology, submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-AM)

-37 of 69-

### Jackson, S.; Kesterson, A.; Lawrence, L. (1988) Soil Surface Photo- lysis of ?Carbon 14|Mesurol in Natural Sunlight: Report No. 1148: Pr oject No. 220. Unpublished study prepared by Pharmaco- logy and Toxicology Research Laboratory. 71 p.

Kazano, H.; Kearney, P.; Kaufman, D. (1972) Metabol ism of methyl- carbamate insecticides in soils. J. Agr. Food Chem. 20(5):975- 979.

Kesterson, A.; Marsh, J.; Lawrence, B.; et al . (1988) Photochemical Degradation of ?Carbon 14|Mesurol in Aqueous Solutions: Project No. 214; Report No. 1147. Unpublished study prepared by Pharma- cology and Toxi cology Research Laboratory. 78 p.

Lamb, D.W. (1974) Accumulation and Persistence of Residues in Blue- gill Fish Exposed to ^(R)IMesurol-14C: Report No. 40096. (Un- published study received Mar 26, 1975 under 5F1607; submitted by Mobay Chemical Co rp., Kansas City, Mo.; CDL:094391-AN)

Minor, R.; Atwell, S. (1979) Metabolic Fate of Mesurol in Aerobic and Anaerobic Aquatic Environments:Mobay Report No. 66775. Un- publis hed study prepared by Mobay Chemical Corp. 22 p.

Minor, R.; Freeseman, P. (1989) Fate of Methiocarb under Aerobic and Anaerobic Soil Conditions: Project ID 99206. Unpublished st udy prepared by Mobay Corp. 71 p.

Mobay Chemical Corporation (1970) Persistence of Mesurol (Bay 37344) in Soil. (Compilation; unpublished study, including re- port nos. 26883 and 26880, received May 20, 1971 under 3125- 257; CDL:050509-B)

Mobay Chemical Corp. (1970) Mesurol (Bay 37 344): Metabolic, Analyt- ical, Residue, and Flavor Information (Apples and Pears). (Com- pilation; unpublished study received Sep 9, 1971 under 1G1030; CDL:091909-A; 091907)

Mobay Chemical Corp. (1971) ?Mesurol: Analyt ical and Residue In- formation for Seed Treatment of Corn|. (Compilation; unpub- lished study received Feb 14, 1973 under unknown admin. no.; CDL:126889-A)

Mobay Chemical Corp. (1974) Metabolism of [Carbon-14]-Labeled Me- thiocarb (4- Methylthio)-3,5-xylyl Methylcarbamate) in Soil and Water: 38747. Unpublished study. 20 p.

Mobay Chemical Corp. (1979) Mesurol: The Ef fects on the Environ- ment--Environmental Chemistry: Document No. AS79-995. (Com- p ilation; unpublished stud y received May 16, 1979 under 7F1879; CDL:098341-A; 098342)

Mobay Chemical Corp. (1979) Mesurol: The Ef fects on the Environ- ment--Environmental Chemistry: Document No. AS79-995. (Com- p ilation; unpublished stud y received May 16, 1979 under 7F1879; CDL:098341-A; 098342)

-38 of 69-

### Mobay Chemical Corp. (1979) Mesurol: The Ef fects on the Environ- ment--Environmental Chemistry: Document No. AS79-995. (Com- p ilation; unpublished stud y received May 16, 1979 under 7F1879; CDL:098341-A; 098342)

Mobay Chemical Corporation (1979) ?Residue of ^(R)IMesurol in Soil|: Report No. 66928. (Compilation; unpublished study, in- cluding report no. 67052, received May 29, 1981 under 3125-288; CDL:070111-D)

Mobay Chemical Corporation (1981) [Product Ch emistry Data for Mes- urol]. Unpublished compilation. 44 p.

Mobay Chemical Corporation (1981) ?Residue of ^(R)IMesurol--Various Crops|: Report No. 45379. (Compilation; unpublished study, incl uding report nos. 45850, 46257, 46436..., received May 29, 1981 under 3125-288; CDL:070112-B)

Mobay Chemical Corp. (1982) Mesurol Addition No. 4 to the Brochure En titled: Mesurol, the
Effects on the Environment--Environment al Chemistry: Document No. AS 82-1813. (Compilation; unpublished study received Jul 16, 1982 under 3125-288; CDL:247869-A)

Murphy, J. (1989) Field Dissipa tion of Mesurol in Sand and Sandy Loam: Proj. ID ME092101. Unpublished Mobay report no. 98512 prepared in cooperation with Wilbu r-Ellis Co., and EPL Bio- Analytical Services, Inc. 300 p.

Ridlen, R. (1987) Soil Leaching of Aged Re sidues of Mesurol. Unpublished Mobay Report 94872 prepared by Mobay Corp., Stanley Research Center. 40 p.

Ridlen, R.; Pfankuche, L. (1987) Adsorption and Desorption of (carbon 14) Mesurol by Soil: Lab Project Number: 95032: MS 719. U npublished study prepared by Mobay Corp. Stanley Research Center. 63 p.

Saakvitne, J.; Gustafson, D.; Wilk es, L.; et al. (1981) Mesurol Hydrolysis in Sterile Buffers: Proj. No. 443. Unpublished Mobay study 69272 prepar ed by Analytical Development Corp. 32

p.

Saakvitne, J.A.; Gustafson, D.E.; Wilkes; L.C.; et al. (1981) ^(R)IMesurol Hydrolysis in Sterile Buffers: ADC Project #443; Report N o. 69272. (Unpublished study received May 29, 1981 under 3125-288; prepared by Analytical Developm ent Corp., sub- mitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:070111-B)

Schiller, L.K. (1981) ?^(R)IMesurol Residue in Soil|: Report No. 69233. (Unpublished study received May 29, 1981 under 3125- 288; prepared in cooperation with Chemonics Industries, submit- ted by Mobay Chemical Cor p., Kansas City, Mo.; CDL:070111-G)

Schiller, L.K. (1981) ?^(R)IMesurol Residue in Soil|: Report No. 69234. (Unpublished study received May 29, 1981 under 3125- 288; prepared in cooperation with Chemonics Industries, submit- ted by Mobay Chemical Corp., Kansas City, Mo.; CDL:070111-H)

-39 of 69-

### Schiller, L.K. (1981) ?^(R)IMesurol Residue in Soil|: Report No. 69236. (Unpublished study received May 29, 1981 under 3125- 288; prepared in cooperation with Everglades Laboratories, Inc., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL: 070111-I)

Spare, W. (1987) Determination of Adsorption/ Desorption Constants of (Inert Ingred.): Lab. Study No. 1278. Unpublished study prepar ed by Agricsearch, Inc. 129 p.

Stanley, C.W.; Parker, G.D. (1981) Octanol/Water Pa rtition Co- efficient a nd Water Solubility of ^(R)IMesurol: Report No. 69271. (Unpublished study received May 29, 1981 under 3125-288; submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:070112-C)

Starr, R.I.; Cunningham, D.J. (1973) Metabolism of 14C-labeled Meth iocarb ?(4-methylthio)- 3,5-xylyl methyl carbamate| in Soil and Water: Report No. 38747. (U.S. Fish and Wildlife Service, Denver Wildlife Research Ce nter, unpublished study; CDL: 094391-AE)

Thornton, J.S.; Hurley, J.B.; Obrist, J.J. (1976) Soil Thin-Layer Mobility of Twenty Four Pesticides (sic) Chemicals: Report No. 51016. (Unpublished study received Jan. 28, 1980 under 5F1547; submitted by Mobay Chemical Corp., Pittsburgh, Pa.; CDL: 099216-I)

Tweedy, B.G.; Houseworth, L.D. (1974) Leaching of Aged Residues of ^(R)IMesurol-ring-1- 14C in Sandy Loam Soil: Report No. 40568. (Unpublished study received Mar 26, 1975 under 5F1607; submit- ted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-AP)

Winkler, V. (2000) Methiocarb So il Dissipation Testing on a Range of Representative Soils: Lab Project Number: 112700: 98512: ME092101. Unpublished study prepared by Mobay Chemical Corp. and Bayer PLC. 271 p. {OPPTS 835.6100}

SUBMITTED EFFECTS STUDIES:

MRID:

22923 Hill, E.F.; Heath, R.G.; Spann, J.W.; et al. (1975) Lethal Dietary Toxicities of Environmental Pollutants to Birds: Special Scientific Report--Wildlife No. 191. (U.S. Dept. of the Interior, Fish and Wildlife Service, Patuxent Wild life Research Center; unpublished report)

36466 Eddy, B.P. (1969) To Assess the Effects of Methiocarb Pellets on Soil Fauna: Technical Report No. 600; Report No. 28287. (Un- pub lished study received Mar 26, 1975 under 5F1607; prepared by Baywood Chemicals, Ltd., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-D)

36481 Lamb, D.W.; Jones, R.E. (1973) Toxicity of (R)Mesurol 75% Wettable Powder to English Sparrows, Bobwhite Quail and New Zeala nd Rabbits under Simulated Field Conditions: Report No. 35970. (Unpublished study received Mar 26, 1975 under 5F1607; submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-Y)

36482 Schafer, E.W., Jr.; Brunton, ? (1973) Toxi city and Repellancy Tests of 9 Materials from Bayer and Chemagro: Report No. S-225; Re - port No. 36054. (Unpublished study including report nos. S-223 and 36055, received Mar 26, 19 75 under 5F1607; prepared in co- operation with U.S. Fish and Wildlife Service, Denver Wildlife Research Center, submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-Z)



### -40 of 69-36483 Colburn, R.; Asquith, D. (19??) Tolerance of Stethorus punctum adults and larvae to various pesticides. Journal of Economic Entomolo gy 66(4):961-962. (Submitter report no. 36414; also In unpublished submission received Mar 26, 1975 under 5F1607; submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL: 094391-AA)

36484 Lamb, D.W.; Roney, D.J. (1973) Acute Toxicity of ^(R)IMesurol 75% Wettable Powder to Bluegill and Rainbow Trout: Report No. 36612. (Unpublished study received Mar 26, 1975 under 5F1607; submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-AB)

36485 Colburn, R.B. (1972) Laboratory Evalua tion of Mesurol on~Stethorus~ ?~punctum~Adults: Report No. 37606. (Pennsylvania, Dept. of Ag- riculture, Fruit Research Laboratory, unpublished study; CDL: 094391-AC)

36491 Schafer, E.W., Jr.; Brunton, R.B.; Lockyer, N.F.; et al. (1973) The Chronic Toxicity of Methiocarb to Grackles, Doves, and Quail and Reproductive Effects in Quail: Report No. 39615. (U.S. Fish and Wildlife Service, Denver Wildlife Research Center, unpublished study; CDL:094391-AJ)

36492 Hermann, ? (1973) Earthw orm Toxicity: Report No. RgE 11; Report No. 39766. (Unpublished study received Mar 26, 1975 under 5F1607; prepared by Bayer, AG, submitted by Mobay Chemical Corp., Kan sas City, Mo.; CDL:094391-AK)

36935 Atkins, E.L.; Greywood, E.A.; Macdonald, R.L. (1975) Toxicity of Pesticides and Other Agricultural Chemicals to Honey Bees: Labo- ra tory Studies. By University of California, Dept. of Entomolo- gy. ?: UC, Cooperative Extension. (Leaflet 2287; published study.)

37798 Atkins, E.L., Jr.; Anderson, L.D.; Todd, F.E. ; et al. (1961) ?Ef- ficacy of Pesticides on Honey Bees|: Report No. 8576. (Unpub- lished stud y received Mar 26, 1975 under 3125-EX-119; prepared by Univ. of California--Riverside, Dept. of Entomology, sub- mitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094390-H)

37799 Johansen, C. (1961) Bee Poisoning Inves tigations, 1961: Report No. 8577. (Unpublished study received Mar 26, 1975 under 3125- EX- 119; prepared by Washington State Univ., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094390-I)

37821 Martin, T.J. (1968) A Cage Test To Study the Palatability and Possible Toxicity of 5622b (Blue) Pellets (4% Methiocarb) to Semi-Domesticated Pheasants (?~Phasianus colchicus~?): Technical Report No. T.F. 423; Report No. 23192. (Unpublished study re- ceived Mar 26, 1975 under 3125-EX-119; prepared by Ba ywood Chemicals, Ltd., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094390-AO)

37822 Cunningham, D.; Schafer, E.W., Jr. (1968) ?Toxicity Studies on Birds|: Report No. 23196. (U.S. Fish and Wildlife Service, Denver Wildlif e Research Center, unpublished study; CDL: 094390-AP)

37823 Boddington, D.G.; Martin, T.J. (1968) A Field Study To Discover Any Evidence of AcuteToxicity to Birds of 5622b Pellets Used as a Molluscicide, and Observations on the Nonacceptability of 5622b Pellets to a Population of House Sparrows: Technical Report No. T.F. 422; Report No. 23622. (Unpublished study r eceived Mar 26, 1975 under 3125-EX-119; prepared by Baywood Chemicals, Ltd., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094390-AQ)

37826 Walker, J.O. (1968) A Trial to Access the Consequences of Feeding Chickens with Methiocarb Poisoned Slugs and Methiocarb Pellets: Technical Report No. TR 541; Report No. 24546. (Unpublished study received Mar 26, 1975 under 3125-EX-119; prepared by



### -41 of 69-Baywood Chemicals, Ltd., submitted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094390-AT)

37828 Myram, C. (1968) Observations on Wildlife Effects following the Application of Methiocarb Pellets: Toxicological Report No. 167; Report No. 24775. (Unpublished study received Mar 26, 1975 under 3125-EX-119; submitted by Mo bay Chemical Corp., Kansas City, Mo.; CDL:094390-AV)

37845 University of California, Agricultural Extension (19??) Toxicity of Pesticides and Other Agricultural Chemicals to Honey Bees. ?: UC, AES. (Submitter report no. 29844; also In unpublished submission received Apr 25, 1975 under 5F1607; subm itted by Mobay Chemical Corp., Kansas City, Mo.; CDL:094391-AS)

60625 Johansen, C.; Hutt, R. (1962) Bee Pois oning Investigations, 1962: Report No. 10617. (Unpublished study received Mar 27, 1974 un- der 4F1485; prepared by Washington State Univ., submitted by Chemagro Corp., Kansas City, Mo.; CDL:092011-E)

81142 Mobay Chemical Corporation (1964) Toxici ty and Repellency Studies with Bayer 37344 on Wild Birds and Rodents: Report No. 9567B. (C ompilation; unpublishe d study received Mar 23, 1970 under 3125-234; CDL:007173-AD)

094390 Shafer, E.W. (1965) Secondary Hazard to Ha wks. 1 p. Study conducted by Denver Wildlife Research Center. Submitted by Chemagro; re g # 3125-234/288; Acc. # 094390 (report 16190 – in part).

094391 Toxicological Evaluation of Three Chemagro Chemicals with Fish (1970) Gulf South Research Institute, Chemagrol 5F1607.

127638 Nelson, D.; Roney, D. (1979) Acute Toxi city of Mesurol Technical to Daphnia magna: Report No. 67264. (Unpublished study re- cei ved Sep 14, 1979 unde r 3125-288; submitted by Mobay Chemical Corp., Kansas City, MO; CDL:098965-D)

128119 Lamb, D.; Carsel, M.; Mallicoat, D.; et al . (1982) Methiocarb Re- production Study with Bobwhite Quail: 82400. (Unpublished stud y received Feb 10, 1983 under 3125-234; submitted by Mobay Chemi- cal Corp., Kansas City, MO; CDL:071396-A)

128120 Lamb, D.; Carsel, M.; Mallicoat, D.; et al . (1982) Methiocarb Re- production Study with Mallard Duck: 82398. (Unpublished study recei ved Feb 10, 1983 unde r 3125-234; submitted by Mobay Chemi- cal Corp., Ka nsas City, MO; CDL:071396-B)

128121 Carlisle, J.; Carsel, M.; Lamb, D.; et al . (1982) A Laboratory Study Exposing Bobwhite Quail to Mesurol 2% Bait: 82399. (Un- publis hed study received Feb 10, 1983 under 3125- 234; submitted by Mobay Chemical Corp., Kansas City, MO; CDL:071396-C)

128122 Carlisle, J.; Toll, P.; Lamb, D.; et al. (1982) Small Pen Field Study of Mesurol 2% Bait Toxicity To Bobwhite Quail: 82674. (Unpub lished study received Feb 10, 1983 under 3125- 234; submit- ted by Mobay Chemical Corp., Kansas City, MO; CDL:071396-D)

150383 Marking, L.; Chandler, J. (1981) Toxicity of six bird control chem- icals to aquatic organisms. Bull. Environm. Contam. Toxicol. (26):705-716.

150628 Lamb, D. (1981) Acute Toxicity of Technical Methiocarb (Mesurol) to Bluegill and Rainbow Trout: Study Nos. 81-066-03 and 80-066-12: Mobay Report No. 69407. Unpublished study prepared by Mobay Chemical Co. 9 p.

155049 Hermann (1983) Bird Toxicity, Oral: Japan ese Quail (Coturnix cotur- nix Japonica): [Test



### -42 of 69-Compound Mesurol]: Report No. VW-76. Un- published study prepared by Bayer AG. 2 p.

155967 Carlisle, J. (1985) Toxicity of Methiocarb (Mesurol) Technical to Early Life Stages of Rainbow Trout: Study No. 85-666-02: 90579. Unpublished study prepared by Mobay Chemical Corp. 19 p.

2046935 Bayer A.G., Pflanzenshutz Anwendungstechni k, Biological Research, Report No. FF-105.

40098001 Mayer, F.; Ellersieck, M. (1986) Manual of Acute Toxicity: Inter- pretation and Data Base for 410 Chemicals and 66 Species of Freshwater Animals. US Fish & Wildlife Service, Resource Pub- lication 160. 579 p.

40560001 Dolbeer, R.; Avery, M.; Tobin, M. (1988 ) Assessment of Field Hazards to Birds and Mammals from Methiocarb Applications to Fruit Crops: Report No. 87266. Unpublished compilation. 1198 p .

40615001 Greig-Smith, P.; Hardy, A.; Brown, P. et al. (1981) Assessment of the Hazard to Wildlife from the Use of Methiocarb To Protect Ripening Cherries: Project No. C/88/0127. Unpublished study prepared by ADAS Tolworth Laboratory. 214 p.

43459801 Kuhn, J. (1994) Acute Oral Toxicity Study in Rats: Metaldehyde-Methiocarb 2-1: Final Report: Lab Project Number: 1380-94. Unpublished study prepared by Stillmeadow, Inc. 24

p.

45743001 Eiben, R.; Bach, U.; Popp, A. (2002) H 321 (Methiocarb): Two-Generation Study in Wistar Rats: Lab Project Number: PH 31760: T4069306: H 321. Unpublished study prepared by Bayer Ag. 937 p. {OPPTS 870.3800}



### -43 of 69-

### APPENDIX A. Label Restrictions for Mesurol ® 

### 75% Wettable Powder Aversive Conditioning Egg Treatment

For Mesurol ® 

### 75% Wettable Powder Aversive Conditioni ng Egg Treatment which is used as a poison for birds that scavenge nests, there are several precautions stipulated on the label that could reduce non-target mortality:

- For retail sale to and use by APHIS (U.S . Department of Agriculture’s Animal and Plant Health Inspection Service) Cer tified Applicators or persons under their direct supervision and only for those us es covered by the Certified Applicator’s
certification.

- Before using, consult with local, state, a nd Federal wildlife aut horities to ensure that the use of the product does not presen t a hazard to threatened or endangered species.

- Do not place eggs treated with the produc t in areas where there is a danger that Threatened or Endangered Species will c onsume them, unless special precautions are taken to limit exposure.
i. Such special precautions may include constant observation while treated eggs are in the field and the use ofhazing tactics to frighten away nontarget species that might feed upon the treated eggs.
ii. If birds of the species to be protec ted feed upon or peck at treated eggs, remove all treated eggs from the field.

- When controlling a protected bird species , it is usually neces sary to obtain a permit from the U.S. Fish and Wildlife Service (USFWS) and/or applicable State Wildlife Agency.

- Prior to utilizing this control method, an endangered species consultation should be conducted with the USFWS to determine if endangered or threatened species
that could or would consume treated e ggs may be present during the treatment period.

- Treated areas must be observed, at least periodically, to monitor the responses of target birds, nesting birds, and other nontarget species. Video equipment may be used to supplement direct observations.

- Place treated eggs in sets of 1 or 2 eggs (apply no more than 20 treated eggs per acre).

- Check egg sets at intervals of 24-hrs or less. Replace eggs that are damaged or removed with fresh treated eggs.

- Unless treatments and monitoring can be c ontinued without adverse effects on the species to be protected, remove all treat ed eggs when these birds begin laying

eggs.

- Carcasses of dead or dying animals should be collected.

-44 of 69-

### APPENDIX B. Toxicity Data for Methiocarb:

TABLE 1. Submitted Toxicity Data for Me thiocarb (Excluding Invalid Studies):

TAXON ENDPOINT FORMULATION MRID STUDY
CLASSIFICATION COMMENTS

BIRDS Birds (Acute) (see additional table below)

Various bird species No endpoint Not reported 40560001 Supplemental Repellency study; nonguideline; no raw data provided; appears to have been a preliminary screening of many chemicals to see
which warranted further investigation as a bird repellent.

Ring-necked

pheasant ( Phasianus
colchicis ) LD 50 = 13.3 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

Horned lark ( Eremophilia

alpestris ) LD 50 = 4.22 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

Japanese quail

( Coturnix

coturnix ) LD 50 = 10 mg a.i./kg-bw (males)

LD 50 = 5-10 mg a.i./kg-bw (females) TGAI (98% a.i.) 00155049 Supplemental No information on bird age or weight change provided; 7-day observation period.

Japanese quail

( Coturnix

coturnix ) LD 50 = 8.84 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines. Starling ( Sturnus vulgaris ) LD 50 = 12 - 15 mg a.i./kg-bw TGAI 81142 Supplemental Only summary data provided
and too few birds used.

Starling ( Sturnus vulgaris ) LD 50 = 11.3 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines. Starling ( Sturnus vulgaris ) LD 50 = 24.2 mg a.i./kg-bw TGAI 00036482 Supplemental Only summary data provided and too few birds used; cannot



### -45 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION be used to fulfill guideline requirements.

Starling ( Sturnus vulgaris ) No endpoint 75% WP (75% a.i.) 40560001 Supplemental Non-guideline aversion study using grapes; no raw data provided. Red-winged

blackbird ( Agelaius phoeniceus ) LD 50 = 11 - 20 mg a.i./kg-bw TGAI 81142 Supplemental Only summary data provided
and too few birds used.

Red-winged

blackbird ( Agelaius phoeniceus ) LD 50 = 4.67 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines. Pigeon ( Columbia livia ) LD 50 = 50 mg a.i./kg-bw TGAI 81142 Supplemental Only summary data provided
and too few birds used.

Eared dove ( Zebauda
auriculata ) LD 50 = 3.16 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines. Ring-billed gull ( Larus
delauarensis ) LD 50 = 5 - 10 mg a.i./kg-bw TGAI 81142 Supplemental Only summary data provided
and too few birds used.

Budgerigar ( Melopsittacus

undulates ) LD 50 = 1.33 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

Cedar waxwing

( Bombycilla
cedrorum ) LD 50 = 5.62 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

Red-billed quelea ( Quelea quelea ) LD 50 = 4.22 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

House finch ( Carpodacus

mexicanus ) LD 50 = 2.42 mg a.i./kg-bw TGAI 00036482 Supplemental Only summary data provided
and too few birds used.



### -46 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION

House finch ( Carpodacus

mexicanus ) LD 50 = 2.37 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

House finch ( Carpodacus

mexicanus ) No endpoint 75% WP (75% a.i.) 40560001 Supplemental Non-guideline aversion study using grapes; no raw data provided.

Sandhill crane ( Grus
Canadensis ) LD 50 = 23.7 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

Golden crowned

sparrow ( Zonotrichia atricapilla ) LD 50 = 3.16 mg a.i./kg-bw TGAI 00036482 Supplemental Only summary data provided
and too few birds used.

Golden crowned

sparrow ( Zonotrichia atricapilla ) LD 50 = 3.16 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.

White crowned

sparrow ( Zonotrichia leucophrys ) LD 50 = 4.21 mg a.i./kg-bw TGAI 00036482 Supplemental Only summary data provided
and too few birds used.

Yellow-headed
blackbird (Xanthocephalus xanthocephalus ) LD 50 = 3.2 mg a.i./kg-bw TGAI 37822 Supplemental Only summary data provided
and too few birds used.

Grackle ( Quiscalus quiscula ) LD 50 = 10 mg a.i./kg-bw TGAI 37822 Supplemental Only summary data provided
and too few birds used.

Brown-headed
cowbird ( Molothrus ater ) LD 50 = 7.5 mg a.i./kg-bw TGAI 37822 Supplemental Only summary data provided
and too few birds used.

Bobwhite quail ( Colinus virginianus ) LD 50 = 2.42 mg a.i./kg-bw TGAI 00036482 Supplemental Only summary data provided
and too few birds used.

Bobwhite quail ( Colinus virginianus ) LD 50 = 19.6 mg a.i./kg-bw Not reported 40560001 Supplemental Procedures varied from test to test but which procedure used for each test was not provided; no raw data provided; procedures were not in accordance with Agency guidelines.



### -47 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION Birds (Acute/Sub-Acute)

Japanese quail

( Coturnix

coturnix ) LC 50 = 1199 mg a.i./kg-diet Mesurol (50% a.i.) 00022923 Supplemental Lack of detail regarding methodology.

Japanese quail

( Coturnix

coturnix ) LC 50 = 1427 mg a.i./kg-diet TGAI (97% a.i.) 00022923 Supplemental Lack of detail regarding methodology.

Ring-necked

pheasant ( Phasianus
colchicis ) LC 50 = 3849 mg a.i./kg-diet Mesurol (50% a.i.) 00022923 Acceptable Lack of detail regarding methodology.

Ring-necked

pheasant ( Phasianus
colchicis ) LC 50 = >5000 mg a.i./kg-diet TGAI (97% a.i.) 00022923 Acceptable Lack of detail regarding methodology.

Ring-necked

pheasant ( Phasianus
colchicis ) No endpoint 4% Methiocarb Pellets (4% a.i.) 37821 Supplemental Non-guideline (repellency study).

Mallard duck ( Anas platyrhynchos ) LC 50 = 2082 mg a.i./kg-diet Mesurol (50% a.i.) 00022923 Acceptable Lack of detail regarding methodology.

Mallard duck (Anas platyrhynchos) LC 50 = 929 mg a.i./kg-diet Mesurol (50% a.i.) 00022923 Acceptable Lack of detail regarding methodology.

Mallard duck ( Anas platyrhynchos ) LC 50 = 4113 mg a.i./kg-diet TGAI (97% a.i.) 00022923 Acceptable Lack of detail regarding methodology.

Mallard duck ( Anas platyrhynchos ) LC 50 = 1071 mg a.i./kg-diet TGAI (97% a.i.) 00022923 Acceptable Lack of detail regarding methodology.

Mallard duck ( Anas platyrhynchos ) LC 50 = >5,000 mg a.i./kg-diet TGAI (97.7% a.i.) 00022923 Acceptable There was 42% mortality at the 5000 ppm concentration.
There was avoidance of
treated food at all treatment levels (lowest 265 ppm).

Grackle ( Quiscalus quiscala ) 28- to 30-day

LC 50 = >100 mg a.i./kg-diet Not reported 36491 Supplemental Too few birds and
concentrations tested to provide statistically significant results; one of four birds in 100 mg a.i./kg-diet treatment
level died.

Mourning dove

( Zenaidura

macroura ) 28- to 30-day

LC 50 = 630 mg a.i./kg-diet Not reported 36491 Supplemental Too few birds and
concentrations tested to provide statistically significant
results.

Japanese quail

( Coturnix

coturnix ) 28- to 30-day

LC 50 = >1000 mg a.i./kg-diet Not reported 36491 Supplemental Too few birds and
concentrations tested to provide statistically significant results; three of six females
and one of six males at the 1000 mg a.i./kg-diet level



### -48 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION
died.

Bobwhite quail ( Colinus virginianus ) NOAEC = 1 lb
a.i./acre 2% Methiocarb Pellets (2% a.i.) 00128122 Supplemental Non-guideline study (small pen field study); no effects seen at the rate tested (1 lb a.i./acre).

Bobwhite quail ( Colinus virginianus ) No endpoint Mesurol 2% Bait (2% a.i.) 128121 Supplemental Non-guideline study; birds
were fed various combinations
of bait and control feed ad libitum; birds were able to pick out food and avoid bait (some repellency); no mortality in 7-day study; weight loss (~20% compared to controls) occurred in birds
that had no control feed
available

Bobwhite quail ( Colinus virginianus ) No endpoint Mesurol 75% wettable powder (75% a.i.) 00036481 Supplemental Non-guideline study; simulated field (5 week) study; no treatment-related effects with 4 applications of 9 lb a.i./acre/application. Sharp-shinned
hawk ( Accipiter

striatus ) No endpoint unknown 094390 Supplemental Non-guideline study; hawk fed for 116 days on red-winged
blackbirds fed methiocarb –
the hawk was ‘unaffected’.

Sparrow hawk ( Accipiter nisus ) No endpoint unknown 094390 Supplemental Non-guideline study; hawk fed for 120 days on red-winged
blackbirds fed methiocarb –
the hawk was ‘unaffected’.

Red-winged
blackbirds ( Turdus merula ) No endpoint Not reported 40560001 Supplemental Non-guideline aversion study;
it is not clear the exact concentration tested; the studydemonstrated visuallyacquired aversion to a repellent (methiocarb).

Chicken ( Gallus gallus

domesticus ) No endpoint 4% Methiocarb Pellets (4% a.i.) 00037826 Supplemental Non-guideline; only three birds per treatment level; birds fed poisoned slugs; no adverse effects to birds noted; birds ‘quickly learned to resist consumption of poisoned slugs’.

English sparrow ( Passer
domesticus ) No endpoint Mesurol 75% wettable powder (75% a.i.) 00036481 Supplemental Non-guideline study; simulated field (5 week) study; no treatment-related effects with 4 applications of 9 lb a.i./acre/application.

House finch ( Carpodacus

mexicanus ) No endpoint 75% wettable powder (75% a.i.) 40560001 Supplemental Non-guideline study; efficacy study; the concentration of
methiocarb on the hulled oats is not known; does provide evidence for repellency in



### -49 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION
birds.

House finch ( Carpodacus

mexicanus ) No endpoint 75% wettable powder (75% a.i.) 40560001 Supplemental Non-guideline efficacy study;
the concentration of
methiocarb on the hulled oats is not known; author states
that finches do not avoid
methiocarb-treated food based on taste; reduction in food
intake could be due to
methiocarb-induced illness.

Field study 0.28 lb a.i./acre 4% Methiocarb Pellets (4% a.i.) 0037823 Supplemental Non-guideline study; 0.28 lb a.i./acre applied to barley field; bird census onlyextended 3 days postapplication. No sick or dead birds observed (dead and dying earthworms common).

Field study 1.9 lb a.i./acre applied to highbush
blueberries Mesurol 75 WP (75% a.i.) 40560001 Supplemental Searches for carcasses did not include off-site areas; carcass searches only conducted 3 days post-treatment; malathion was used concurrently; 5 incapacitated Baltimore orioles (2 adults and 3 juveniles) were observed.

Field study 0.95 or 1.9 lb a.i./acre applied
to blueberries (depending on the field) Mesurol 75 WP (75% a.i.) 40560001 Supplemental Description of how and when
carcass searches were conducted was not provided;
malathion was used concurrently; 7 incapacitated birds (5 robins and 2 Baltimore orioles) were
observed.

Field study 2 applications
of 2 lb a.i./acre applied twice to
cherries Mesurol 75 WP (75% a.i.) 40560001 Supplemental Insufficient description of carcass search effort; carcasssearch only conducted on day6 post-treatment; 3 dead birds (one Brewer blackbird and two grackles) and partially paralyzed starling found.

Field study 2 or 3 applications to

grapes (depending on field); application rate not provided on

DER Mesurol 75 WP (75% a.i.) 40560001 Supplemental Carcass searches not conducted daily after treatments; carcass efficiency and predator removal trials were not conducted; carcass searching not done off-field; 10 incapacitated birds (7 robins, 1 housefinch, and 2 Western bluebirds) found (all recovered within 4 hrs).

Field study 2 or 3 applications to Mesurol 75 WP (75% a.i.) 40560001 Supplemental Carcass searches only
conducted once within first 24



### -50 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION

grapes (depending on the field) at 2.8
lb a.i./acre hrs after treatment; carcass efficiency and predator
removal trials were not conducted; no dead or incapacitated birds found.

Field study 3 applications at
1.9 lb a.i./acre (14-day application interval) to
cherries 50% WP (50% a.i.) 40615001 Acceptable 16 dead or incapacitated birds found [greenfinch (3), blackbird (3), blue tit (2), starling (2), house sparrow (3), linnet (1), chaffinch (1), tree sparrow (1)]; authors attribute 6-12 due to methiocarb;
estimated 25% carcass efficiency = 24 – 48 dead
birds from methiocarb. Birds (Chronic)

Bobwhite quail ( Colinus virginianus ) NOAEC = <2 mg a.i./kg-diet TGAI (97% a.i.) 128119 Supplemental Reproductive effects seen at
the lowest concentration tested (2 ppm).

Mallard duck ( Anas platyrhynchos ) Reproductive
effects : NOAEC = 100 mg a.i./kg-diet

LOAEC - >100 mg a.i./kg-diet
Cholinesterase activity : NOAEC = 50 mg a.i./kg-diet

LOAEC - 100 mg a.i./kg-diet TGAI (97% a.i.) 128120 Acceptable No reproductive effects seen at the highest concentration tested (100 ppm).

Coturnix quail

( Coturnix

coturnix ) NOAEC = 100 mg a.i./kg-diet

LOAEC = 316 mg a.i./kg-diet Not reported 36491 Supplemental Based on reduced egg production and live-chick production; appropriate reproductive parameters were not measured, raw data were not provided, and the experimental procedure not completely described.

MAMMALS Mammals (Acute)

Laboratory rat ( Rattus norvegicus ) LD 50 = 14 mg a.i./kg-bw (males) TGAI 00083437 Acceptable None

Black-tailed prairie dog ( Cynomys
ludovicianus ) No endpoint TGAI (dust) 40560001 Supplemental Non-guideline field study (aversion); grains were dusted and fed to the prairie dogs; study demonstrates repellency;
adults learned to avoid the grain with the methiocarb (and continued grain aversion after treatment ended).



### -51 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION

Fox squirrel ( Sciurus niger

rufiventer ) No endpoint Mesurol Hopper Box Treater (50% a.i.) 40560001 Supplemental Non-guideline aversion study; it is not possible to estimate concentrations tested; raw data not provided; animals avoided
treated food. Ground squirrel (Spermophilus tridecemlineatus) No endpoint Mesurol Hopper Box Treater (50% a.i.) 40560001 Supplemental Non-guideline aversion study; raw data not provided; animals
avoided treated food. Mammals (Chronic)

Laboratory rat
( Rattus norvegicus ) NOAEC = 67 mg a.i./kg-diet (3.35 mg a.i./kg-bw) (based on
cholinesterase

inhibition) TGAI 00115226
and

00128723 Acceptable Based on a chronic dietary study; decreased body weight at 600 mg a.i./kg-diet; LOAEC = 200 mg a.i./kg-diet
based on cholinesterase inhibition; a reproduction study is not available

TERRESTRIAL INVERTEBRATES

Honey bee ( Apis mellifera ) LD 50 < 1.25 lb product/100 gallon (resulted
in 100% mortality) 50% WP (50% a.i.) 00060625 Acceptable Only one concentration tested (tested both with direct application and exposed to dry residues).

Honey bee ( Apis mellifera ) LD 50 < 1 lb product/100 gallon (resulted
in 100% mortality) Mesurol (% a.i. not provided) 0037799 Supplemental Only one concentration tested (tested either with direct application or exposed to dry residues) – based on DER (1978). Direct application resulted in complete mortality within 3 hr; 92-100% mortality resulted fromresidues after 4 days posttreatment.

Honey bee ( Apis mellifera ) LD 50 <0.25%
>0.125% Mesurol (% a.i. not provided) 0037798 Supplemental Applied as a dust (0.125, 0.25, 0.5, 1, 2, 4, and 8% concentrations). After 48 hr, 100% mortality at 4 and 8%; 1.0, 0.5, 0.25, and 0.125% resulted in the following mortalities: 93%, 81%, 58% and 5%, respectively.

Honey bee ( Apis mellifera ) LD 50 = 0.375

μg formulation/bee Mesurol (% a.i. not reported) 00037845 Supplemental None

Honey bee ( Apis mellifera ) LD 50 = 0.375 μg a.i./bee Mesurol 00036935 Acceptable None

Earthworm ( Lumbricus

terrestris Allobophora

rubellus ) LC 50 > 0.8 lb
a.i. Draza pellets (4% a.i.) 00036466 Supplemental Non-guideline study. Earthworm populations were reduced by 1.25, 2.25, and 5% (as compared to controls) for 0.2, 0.4, and 0.8 lb a.i., respectively.

Erthworm 35-day LC 50 TGAI (99.2% a.i.) 00036492 Supplemental Non-guideline study. No



### -52 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION ( Eisenia foetida ) >200 ppm effects noted at 2.5 or 10 ppm); severe damage and some mortality occurred at 50 and 200 ppm; worms were exposed for 10 days.

Ladybird beetle ( Stethorus

punctum ) LD 50 < 0.094 lb a.i./100 gallon

water Mesurol 75% WP (75% a.i.) 00036483 Supplemental Non-guideline study; adult beetles were dipped in solution; after 48-hr, there was complete mortality.

Ladybird beetle ( Stethorus

punctum ) LD 50 < 0.375 lb a.i./100 gallon water (0.5
formulation/100 gallon water) Mesurol 75% WP (75% a.i.) 00036485 Supplemental Non-guideline study; adult beetles were dipped in solution; complete mortality
after 4 hr in the 0.5 lb formulation/100 gallon; complete mortality within 1 hr
at 1 and 2 lb rates.

Field study 0.28 lb a.i./acre 4% Methiocarb Pellets (4% a.i.) 0037823 Supplemental Non-guideline study; 0.28 lb a.i./acre applied to barley field; bird census onlyextended 3 days postapplication. No sick or dead birds observed (dead and dying earthworms common).

Field study 0.20 lb a.i. applied to brussell sprouts
and cauliflower fields. ‘High’ rate applied to garden. 4% Methiocarb Pellets (4% a.i.) 0037828 Supplemental (invertebrate portion) Non-guideline study; only
minimal avifauna investigation. No sick or dead birds observed (dead earthworms, carabid beetles, slugs, and one dead field mouse).

FRESHWATER FISH Freshwater Fish (Acute)

Rainbow trout ( Oncorhynchus mykiss ) LC 50 = 4.7 mg
a.i./L TGAI ((8.4% a.i.) ACC No.
2046935 Supplemental Tanks were aerated during the study and concentrations were
not measured.

Rainbow trout ( Oncorhynchus mykiss ) LC 50 = 1.4 mg
a.i./L (1.05 mg a.i./L) Mesurol 75% WP (75% a.i.) 36484 Acceptable The results do not appear to
have been corrected for a.i. (the reviewer converted the results for a.i.).

Rainbow trout ( Oncorhynchus mykiss ) LC 50 = 0.436 mg a.i./L TGAI (98% a.i.) 150628 Acceptable None

Rainbow trout ( Oncorhynchus mykiss ) LC 50 = 0.9 mg
a.i./L TGAI (% a.i. not reported) 094391 Supplemental No method of statistical analysis provided.

Rainbow trout ( Oncorhynchus mykiss ) LC 50 = 0.672 mg a.i./L TGAI (99% a.i.) 40098001 Supplemental Insufficient study details; no slope could be calculated.

Bluegill sunfish ( Lepomis
macrochirus ) LC 50 = 0.182 mg a.i./L TGAI (99% a.i.) 40098001 Supplemental Insufficient study details; slope = 4.4 (95% CI = 1.9, 6.9). Bluegill sunfish LC 50 = 1.9 mg Mesurol 75% WP 36484 Accep table The results do not appear to



### -53 of 69-TAXON ENDPOINT FORMULATION STUDY

MRID COMMENTS CLASS-
IFICATION ( Lepomis
macrochirus ) a.i./L (1.4 mg a.i./L) (75% a.i.) have been corrected for a.i. (the reviewer converted the results for a.i.). Bluegill sunfish ( Lepomis
macrochirus ) LC 50 = 0.754 mg a.i./L TGAI (98% a.i.) 150628 Acceptable None

Catfish LC 50 = 4.6 mg
a.i./L TGAI (% a.i. not reported) 094391 Supplemental No method of statistical analysis provided.

Goldfish ( Carassius

auratus auratus ) LC 50 = 5.1 mg
a.i./L TGAI (% a.i. not reported) 094391 Supplemental No method of statistical analysis provided.

Freshwater Fish (Chronic)

Rainbow trout ( Oncorhynchus mykiss ) NOAEC = 0.050 mg a.i./L

LOAEC = 0.10 mg a.i./L TGAI (97% a.i.) 00155967 Supplemental Lack of raw environmental data; based on clinical signs of intoxication (behavior); significant mortality, weight
reduction and effect on larval swimup ≥ 0.20 mg a.i./L. Amphibian (Acute) Frog larvae (aquatic-phase) ( Rana spheocephala ) 96-hr LC 50 = 8.7 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods.

ESTUARINE/MARINE FISH Estuarine/Marine Fish (Acute)
No data

FRESHWATER INVERTEBRATES Freshwater Invertebrates (Acute) Daphnid ( Daphnia magna ) EC 50 = 0.019 mg a.i./L TGAI 127638 Acceptable None

Glass shrimp ( Palaemonetes

kadiakensis ) 96-hr LC 50 = 0.11 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods. Crayfish ( Procambarus

acutus acutus ) 96-hr LC 50 = 1.3 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods.

Mayfly ( Isonychia sp .) 96-hr LC 50 = 0.007 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods.

Caddisfly larvae ( Hydropsyche sp.) 96-hr LC 50 = 0.014 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods.

River horn snail ( Oxytrema

catenaria ) 96-hr LC 50 = 0.10 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods.

Asiatic clam ( Corbicula
menilensis ) 96-hr LC 50 = 8.8 mg a.i./L TGAI 150383 Supplemental Lack of raw data and adequate information describing
materials and methods. Stonefly ( Pteronarcys californica ) 96-hr LC 50 = 0.0055 mg
a.i./L TGAI (99% a.i.) 40098001 Supplemental Insufficient study details; no slope could be calculated



### -54 of 69-

### -55 of 69- TAXON ENDPOINT FORMULATION MRID STUDY
CLASSIFICATION COMMENTS

Freshwater Invertebrates (Chronic)
No data

ESTUARINE/MARINE INVERTEBRATES Estuarine/Marine Invertebrate (Acute)
No data AQUATIC PLANTS Aquatic Plants (Non-Vascular)
No data

BIOACCUMULATION
No dataAPPENDIX C. Chemical Names and Stuctures forMethiocarb and its Environmental Degradatesmethiocarb [3,5-dimethyl-4-)methylthio)phenol methylcarbamate]methiocarb phenol (MP) [3,5-dimethyl-4-(methythio)=phenol]R1= -OHR2= -SCH3-56 of 69-methiocarb sulfoxide (MSO) [3,5-dimethyl-4-(methylsul=phenyl)phenyl methylcarbamate]O"R1= -O-C-NH-CH3O‘'R2= -SCH3methiocarb sulfoxide phenol (MSOP)[3,5-dimethyl-4-(methylsul=phinyl)phenol]R1= -OHO‘'R2= -SCH3-57 of 69-methiocarb sulfone (MSO2) [3,5-dimethyl-4-(methylsul=phonyl)phenyl methylcarbamate]-58 of 69-O"R1= -O-C-NH-CH3O‘'R2= -SCH3“Omethiocarb sulfone phenol (MSO2P) [3,5-dimethyl-4-(methylsul=phonyl)phenol]R1= -OHO‘'R2= -SCH3“O

### APPENDIX D: Data Call-In Tables.

The Environmental Fate and Effects Division (EFE D) has completed a Data Call-In (DCI) table
for the methiocarb environmental fate and effects data gaps identified in Registration Review. The attached DCI tables, which include the gui deline number and study title for required data, also provide a rationale for requiring the data, an explanation of how the data will be used, and a brief description of how the data could im pact the Agency’s future decision-making.

Environmental Fate Data:

Guideline Number: 835.4100 Study Title: Aerobic Soil Metabolism Compound: Methiocarb Rationale for Requiring the Data Acceptable data on the aerobic soil metabolism of methiocarb are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial and/or residential outdoor uses. The Agency has a limited understanding of the environmental fate of methiocarb in the
environment. Aerobic soil metabolism data for at least three additional soils, representative of intended use areas, must be submitted to the Agency. Practical Utility of the Data

How will the data be used? Currently there are limited aerobic soil metabolism data that provide information on the fate of methiocarb and its degradates in soil. The submitted data will be used to help characterize and quantify the environmental fate of methiocarb and its degradates in the environment. For quantitative exposure estimation, these data will be used in modeling estimated environmental concentrations (EECs) of methiocarb for the aquatic exposure assessment.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data, a single stud y will be used to represent microbial metabolism in all soils. This assumption will contribute to uncertainty in the risk assessment.

Guideline Number: 835.4300 Study Title: Aerobic Aquatic Metabolism Active Ingredient: Methiocarb Rationale for Requiring the Data Acceptable data on the aerobic aquatic metabolis m of methiocarb are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Because the current labels do not specifically exclude use on field-grown ornamentals, data requirements for terrestrial uses apply. The Agency has a limited understanding of the environmental fate of
methiocarb in the environment. Data on the aer obic aquatic metabolism of methiocarb have not been submitted to the Agency. Practical Utility of the Data

How will the data be used? The Agency has a limited understanding of the fa te of methiocarb and its degradates in aquatic
environments. The submitted data will be used to characterize and quantify the environmental



### -59 of 69-fate of methiocarb and its degradates in a quatic environments. For quantitative exposure estimation, these data are used to model estimated environmental concentrations (EECs) of methiocarb for the aquatic exposure assessment.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data and consis tent with EFED model input parameter guidance, the aerobic aquatic metabolism half-life used to model EECs for methiocarb will be conservatively assumed to be equal to two time s the modeling input value for the aerobic soil metabolism half-life, which will be based on tota l toxic residues rather than on parent alone. Implicit in this assumption is that all of the aerobic soil degradates are assumed to also be present in aquatic environments. This may not be the case. This assumption could overestimate risk in aquatic environments.

Guideline Number: 835.4400 Study Title: Anaerobic Aquatic Metabolism Active Ingredient: Methiocarb Rationale for Requiring the Data Acceptable data on the anaerobic aquatic metabo lism of methiocarb are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Because the current labels do not specifically exclude use on field-grown ornamentals, data requirements for terrestrial uses apply. The Agency has a lim ited understanding of the environmental fate of
methiocarb in the environment. Data on the anaerobic aquatic metabolism of methiocarb have not been submitted to the Agency. Practical Utility of the Data

How will the data be used? The Agency has a limited understanding of the fa te of methiocarb and its degradates in aquatic
environments. The submitted data will be used to characterize and quantify the environmental fate of methiocarb and its degradates in a quatic environments. For quantitative exposure estimation, these data will be used to model estim ated environmental concentrations (EECs) of methiocarb for the aquatic exposure assessment inst ead of using a default value to represent the anaerobic aquatic metabolism half-life of the compound.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data and consis tent with EFED model input parameter guidance, the anaerobic aquatic metabolism half-life u sed to model EECs for methiocarb will be conservatively assumed to be equal to two times the modeling input value for the anaerobic soil metabolism half-life, which will be based on tota l toxic residues rather than on parent alone. Implicit in this assumption is that all of the anaerobic soil degradates are assumed to also be present in aquatic environments. This may not be the case. This assumption could overestimate risk in aquatic environments.

Guideline Number: 835.1230 and 835.1240 Study Title: Leaching and adsorption/desorption Compound: Methiocarb Rationale for Requiring the Data Acceptable data on the leaching and adsorption/d esorption of methiocarb are required under 40



### -60 of 69-CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial and/or residential outdoor uses. The Agency has a lim ited understanding of the environmental fate of methiocarb, particularly with respect to potentia l leaching. Acceptable ad sorption/desorption data have not been submitted to the Agency. Practical Utility of the Data

How will the data be used? Currently there are no acceptable leaching and adsorption/desorption studies that provide information on the potential leaching behavior of methiocarb in soil. The submitted data will be used to help characterize and the environmental fate of methiocarb in the environment. For quantitative exposure estimation, these data will be used in modeling estimated environmental concentrations (EECs) of methiocarb for the a quatic exposure assessment. Adsorption/ desorption data using the batch equilibrium method are preferred. If the compound is not stable during a batch equilibrium study, then soil column leaching met hods (aged and unaged) may be more appropriate.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data, the poten tial leaching behavior of methiocarb will be unknown, and will contribute to the uncertainty in the risk assessment. The potential for leaching to groundwater will not be able to be precluded in the assessment.

Guideline Number: 835.1230 and 835.1240 Study Title: Leaching and adsorption/desorption Compound: Methiocarb phenol (MP) Rationale for Requiring the Data Acceptable data on the leaching and adsorption/desorption of methiocarb phenol (MP), a degradate of methiocarb, are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial and/or residential outdoor uses. The Agency has a limited understanding of the environmental fate of MP, particularly w ith respect to potential leaching. Acceptable adsorption/desorption data have not been submitted to the Agency. Practical Utility of the Data

How will the data be used? Currently there are no acceptable leaching and adsorption/desorption studies that provide information on the potential leaching behavior of MP in soil. The submitted data will be used to help characterize and the environmental fate of MP in the environment. For quantitative exposure estimation, these data will be used in modeling es timated environmental concentrations (EECs) of MP for the aquatic exposure assessment. Adsorption/ desorption data using the batch equilibrium method are preferred. If the compound is not stable during a batch equilibrium study, then soil column leaching methods (aged and unage d) may be more appropriate.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data, the potentia l leaching behavior of MP will be an unknown, and will contribute to uncertainty in the risk assessment. The potential for leaching to groundwater will not be able to be precluded in the assessment.



### -61 of 69-Guideline Number: 835.1230 and 835.1240 Study Title: Leaching and adsorption/desorption Compound: Methiocarb sulfoxide (MSO) Rationale for Requiring the Data Acceptable data on the leaching and adsorption/desorption of methiocarb sulfoxide (MSO), a degradate of methiocarb, are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial and/or reside ntial outdoor uses. The Agency has a limited understanding of the environmental fate of MSO, pa rticularly with respect to potential leaching. Acceptable adsorption/desorption data have not been submitted to the Agency. Practical Utility of the Data

How will the data be used? Currently there are no acceptable leaching and adsorption/desorption studies that provide information on the potential leaching behavior of MS O in soil. The submitted data will be used to help characterize and the environmental fate of MSO in the environment. For quantitative exposure estimation, these data will be used in modeling estimated environmental concentrations (EECs) of MSO for the aquatic exposure assessment . Adsorption/ desorption data using the batch equilibrium method are preferred. If the compound is not stable during a batch equilibrium study, then soil column leaching methods (aged a nd unaged) may be more appropriate.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data, the potentia l leaching behavior of MSO will be an unknown, and will contribute to uncertainty in the risk assessment. The potential for leaching to groundwater will not be able to be precluded in the assessment.

Guideline Number: 835.1230 and 835.1240 Study Title: Leaching and adsorption/desorption Compound: Methiocarb sulfoxide phenol (MSOP) Rationale for Requiring the Data Acceptable data on the leaching and adsorpti on/desorption of methiocarb sulfoxide phenol (MSOP), a degradate of methiocarb, are required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial and/ or residential outdoor uses. The Agency has a limited understanding of the environmental fate of MSOP, particularly with respect to potential leaching. Acceptable adsorption/desorption data have not been submitted to the Agency. Practical Utility of the Data

How will the data be used? Currently there are no acceptable leaching and adsorption/desorption studies that provide information on the potential leaching behavior of MS OP in soil. The submitted data will be used to help characterize and the environmental fate of MSOP in the environment. For quantitative exposure estimation, these data will be used in modeling estimated environmental concentrations (EECs) of MSOP for the aquatic exposure assessme nt. Adsorption/ desorption data using the batch equilibrium method are preferred. If the compound is not stable during a batch equilibrium study, then soil column leaching methods (aged a nd unaged) may be more appropriate.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking? In the absence of the requested data, the potential leaching behavior of MSOP will be an unknown, and will contribute to uncertainty in the risk assessment. The potential for leaching to groundwater will not be able to be precluded in the assessment.



### -62 of 69-Guideline Number: 835.6100 Study Title: Analytical Method (and Associated Independent Laboratory Validations) in Soil Compound: Methiocarb Rationale for Requiring the Data Acceptable data on the analytical method in so il (and the associated independent laboratory validations) of methiocarb are required under 40 CFR Part 158, Subpart N (revised July 1, 2009). Independently validated analytical methods for resi dues in soil, water, sediment, and plant material (environmental chemistry methods) submitted by the registrant are used to evaluate analyses
described in submitted environmental fate and eco logical effects studies. Submitted analytical methods are also used by various Federal, State, Tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory va lidations for submitted analytical methods are necessary to confirm that the methods are functiona l and to confirm the levels of detection and quantitation reported in registrant-prepared validations.

Use of methiocarb may impact surface water quality due to runoff of rainwater and drift of residues. This is especially true for poorly draining soils, erodible soils, and soils with shallow ground water. Therefore, outside agencies may request analytical methods with which to monitor
for methiocarb residues in water and in soil. Practical Utility of the Data

How will the data be used? In the absence of independently validated environmental chemistry methods, submitted environmental fate and ecological effects data may not be reviewable and entities outside the Agency may lack chemical-specific methods fo r analyses in environmental compartments. Independently validated environmental chemistr y methods will be used to evaluate newly submitted environmental fate and ecological e ffects data and will be made available for enforcement and monitoring purposes at th e federal, state, and local levels.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking?
Risk assessment conclusions could be altered if th ey are not supported by either study data or environmental monitoring detections that are based on independently validated environmental chemistry methods. Furthermore, while not di rectly related to Agency decision-making, independently validated environmental chemistr y methods are necessary to ensure the safety of those in proximity to releases of me thiocarb residues in the environment.

Guideline Number: 835.6200 Study Title: Analytical Method in Water Compound: Methiocarb Rationale for Requiring the Data Acceptable data on the analytical method in so il (and the associated independent laboratory validations) of methiocarb are required under 40 CFR Part 158, Subpart N (revised July 1, 2009). Independently validated analytical methods for resi dues in soil, water, sediment, and plant material (environmental chemistry methods) submitted by the registrant are used to evaluate analyses
described in submitted environmental fate and eco logical effects studies. Submitted analytical methods are also used by various Federal, State, Tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory va lidations for submitted analytical methods are necessary to confirm that the methods are functiona l and to confirm the levels of detection and



### -63 of 69-quantitation reported in registrant-prepared validations.

Use of methiocarb may impact surface water quality due to runoff of rainwater and drift of residues. This is especially true for poorly draining soils, erodible soils, and soils with shallow ground water. Therefore, outside agencies may request analytical methods with which to monitor
for methiocarb residues in water and in soil. Practical Utility of the Data

How will the data be used? In the absence of independently validated environmental chemistry methods, submitted environmental fate and ecological effects data may not be reviewable and entities outside the Agency may lack chemical-specific methods fo r analyses in environmental compartments. Independently validated environmental chemistr y methods will be used to evaluate newly submitted environmental fate and ecological e ffects data and will be made available for enforcement and monitoring purposes at th e federal, state, and local levels.

How could the data change the Agency’s decision or impact the Agency’s future decisionmaking?
Risk assessment conclusions could be altered if th ey are not supported by either study data or environmental monitoring detections that are based on independently validated environmental chemistry methods. Furthermore, while not di rectly related to Agency decision-making, independently validated environmental chemistr y methods are necessary to ensure the safety of those in proximity to releases of methiocarb residues in the environment.

Guideline Numbers: 850.1730 Study Title: Fish Bioconcentration Study Rationale for Requiring the Data

Bioconcentration data are not available for methiocarb and fish. A fish bioconcentration study is required under 40 CFR Part 158 when the octanol/water partition coefficient of the chemical is >1,000; there are potential exposures to fish and other non-target aquatic an imals; and the hydrolysis half-life is >5 days at pH 5, 7, and/or 9. All of these criteria are met with methiocarb. Therefore, since these data are not currently available, EFED recommends requesting these da ta at this time. In the absence of such data, it will be assumed that methiocarb bioconcentrates in food, and, therefore, risks to both listed and nonlisted aquatic species (and those that eat aquatic species) will be presumed in the risk assessment conducted for Registration Review. Practical Utility of the Data

How will the data be used?
Fish bioconcentration data will be used to refine the screening-level assessment by determining whether there are potential risks to animals inhabiting aquatic environments and those that eat aquatic animals
from the use of methiocarb. If bioconcentration data are not submitted for fish, risk will be presumed for animals in aquatic environments and those that eat aquatic animals potentially exposed to methiocarb.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to presume that methiocarb “may affect” listed aquatic animal species directly (and listed species from other taxa indirectly), and use of methiocarb and its formulated products may need to be restricted in areas where listed species could be exposed. The l ack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for methiocarb use that are unnecessarily severe.



### -64 of 69-

### Ecological Effects Data:

Guideline Number: 850.2300 Study Title: Avian Reproduction Test (Bobwhite Quail) Rationale for Requiring the Data Under the 40 CFR Part 158 (July 1, 2009) avian re production data are require d on waterfowl and upland game species (OPPTS 850.2300). Currently acceptable data for methiocarb are only available for waterfowl. The chronic toxicity data available fo r birds indicate that bobwhite quail (NOAEC <2 mg a.i./kg-diet based on reduced survival of 14-da y old birds and reduced eggshell thickness) (MRID 128119) are more sensitive to methiocarb than mallard duck (NOAEC = 100 mg a.i./kg-diet, the highest concentration tested) (MRID 128120). Since a definitive NOAEC for bobwhite quails is not available (the lowest dose tested resulted in effects), the speci fic risk to birds from chronic exposure to methiocarb is unknown. Therefore, in order to complete the risk assessment, additional da ta are needed. In the absence of such data, risks to both listed and non- listed bird species will be presumed in the risk assessment conducted for Registration Review. Practical Utility of the Data

How will the data be used? Reproduction data for bobwhite quail will be used to reduce uncertainties associated with using a nondefinitive endpoint for assessing chronic risks to bi rds from methiocarb exposure. If reproduction data are not submitted for bobwhite quail, risks to birds from chronic exposure will be presumed.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to assume that methiocarb “may affect” listed bi rds directly (and listed species from other taxa indirectly), and use of methiocarb and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for methiocarb use that are unnecessarily severe.

Guideline Number: 850.3030 Study Title: 

### Honey Bee Toxicity of Residues on Foliage Rationale for Requiring the Data Under the 40 CFR Part 158 (July 1, 2009) data on h oney bee toxicity of residues on foliage are required (OPPTS 850.3030) when the acute honey bee contact LD 50 <11 μg/bee and the use pattern(s) indicate(s) that honey bees may be exposed to th e pesticide. The acute contact LD 50 for methiocarb is 0.375 μg a.i./bee (MRID 00036935). Furthermore, the use of foliar methiocarb on ornamentals (some of which may be flowering) represents a route of potential exposure to honey bees. Therefore, in order to complete the risk assessment, additiona l data are needed. In the absen ce of such data, risks to honey bees will be presumed in the risk assessmen t conducted for Registration Review. Practical Utility of the Data

How will the data be used? Honey bee toxicity of residues on foliage data w ill be used to reduce uncertainties associated with assessing risks to honey bees from methiocarb exposure. In the absence of such data, risks to honey bees will be presumed in the risk assessmen t conducted for Registration Review.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to presume that methiocarb “may affect” listed terrestrial invertebrates directly (and listed species from other taxa indirectly), and use of methiocarb and its formulated products may need to be restricted in



### -65 of 69-areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for methiocarb use that are unnecessarily severe.

Guideline Numbers: 850.1075, 850.1025, and 850.1035, 850.1045, or 850.1055 Study Title: Estuarine/Marine Fish and Invertebrate Acute Toxicity Tests Rationale for Requiring the Data Acute toxicity data for methiocarb are not available for estuarine/marine fish or invertebrates. Acute toxicity data on a saltwater fish (850.1075), saltwater mollusk (850.1025), and a saltwater invertebrate (850.1035, 850.1045, or 850.1055) are required under 40 CFR Part 158. Since these data are not currently available, EFED recommends requesting these da ta at this time. In the absence of such data, risks to both listed and non-listed estuarine/marine species will be presumed in the risk assessment conducted for Registration Review. Practical Utility of the Data

How will the data be used? Acute toxicity data for estuarine/marine species will be used to refine the screening-level assessment by determining whether there are potential risks to an imals inhabiting estuarine/marine environments from the use of methiocarb. If acute toxicity data are not submitted for estuarine/marine fish and invertebrates, risk will be presumed for animals in estuarine/marin e environments potentially exposed to methiocarb.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to presume that methiocarb “may affect” listed estuarine/marine fish and invertebrate species directly (and listed species from other taxa indirectly), and u se of methiocarb and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act
and could result in use restrictions for methiocarb use that are unnecessarily severe.

Guideline Number: 850.1300 and 850.1350 Study Title: Invertebrate Life Cycle Toxi city Test (Freshwater and Estuarine/Marine) Rationale for Requiring the Data Acceptable chronic toxicity data for methiocarb are not available for freshwater invertebrates (850.1300) or estuarine/marine invertebrates (850.1350). Since the LC 50 values for the most sensitive invertebrate species tested is < 1 mg/L, estuarine/marine and freshwater invertebrate life cycle studies are required under the new 40 CFR Part 158. Therefore, an estuarine/marine invertebrate life cycle toxicity test (OPPTS Guideline 850.1350) and a freshwater inverteb rate life cycle toxicity test (OPPTS Guideline 850.1300) are required. In the absence of chronic meth iocarb toxicity data for aquatic invertebrates, the Agency will presume risks to aquatic invert ebrates from the use of methiocarb. Practical Utility of the Data

How will the data be used? Chronic toxicity data for estuarine/marine and freshwate r invertebrate species will be used to refine the screening-level assessment by determining whether th ere are potential risks to invertebrates inhabiting
estuarine/marine and/or freshwater environments from th e use of methiocarb. If chronic toxicity data are



### -66 of 69-not submitted for estuarine/marine and freshwater inve rtebrates, risk will be presumed for all aquatic invertebrates potentially exposed to methiocarb.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to presume that methiocarb “may affect” listed aqua tic invertebrate species directly (and listed species from other taxa indirectly), and use of methiocarb and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into co mpliance with the Endangered Species Act and could
result in use restrictions for methio carb use that are unnecessarily severe.

Guideline Number: 850.1400 Study Title: Fish Early Life Stage Toxicity Test (Freshwater and Estuarine/Marine) Rationale for Requiring the Data Acceptable chronic toxicity data for methiocarb are not available for estuarine/marine fish (850.1400) or the most acutely sensitive freshwater fish ( i.e ., bluegill sunfish)(850.1400). A supplemental study is available for freshwater fish, but not for the most acutely sensitive species ( i.e ., bluegill sunfish). Since
the LC 50 values for the most sensitive fi sh species tested is < 1 mg/L, estuarine/marine and freshwater fish early life stage studies are required under the new 40 CFR Part 158. Therefore, a fish early life stage toxicity test (OPPTS Guideline 850.1400) is required for both freshwater and estuarine/marine fish. In the absence of chronic methiocarb toxicity data for fish, an acute-to-chronic ratio (ACR) using rainbow trout data will be used to extrapolate a chronic endp oint for bluegill sunfish and estuarine/marine fish. Practical Utility of the Data

How will the data be used? Chronic toxicity data for estuarine/marine and fresh water fish species will be used to refine the screening-level assessment by determining whethe r there are potential risks to fish inhabiting
estuarine/marine and/or freshwater environments from th e use of methiocarb. If chronic toxicity data are
not submitted for estuarine/marine or freshwater fish , risk will be presumed for all fish potentially exposed to methiocarb.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to presume that methiocarb “may affect” listed fish species directly (and listed species from other taxa indirectly), and use of methiocarb and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of th ese data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for methiocarb use that are unnecessarily severe.

Guideline Numbers: 850.4100 and 850.4150 Study Title: Terrestrial Plant Toxicity Tests (Tier I) Rationale for Requiring the Data Terrestrial plant toxicity studies [both seedling em ergence (850.4100) and ve getative vigor (850.4150)] and associated risk analysis of plants are required for registration of pesticides with outdoor uses (CFR Part 158). Tier I seedling emergence and vegetative vigor studies (OPPTS Guidelines 850.4100 and 850.4150) are, therefore, required. In the absence of su ch data, risks to terrestri al plants from the use of methiocarb will be presumed in th e risk assessment. Tier II studies (850.4225 and 850.4250) may be required depending on the results of the Tier I plant studies.



### -67 of 69-Practical Utility of the Data

How will the data be used? Tier I vegetative vigor and seedling emergence data for terrestrial plants will be used to determine the potential for methiocarb to affect non-target plant speci es in the terrestrial environment. In the absence of data specific for these plants, risk to terrestrial plants will be presumed.

How could the data impact the Agency’s future decision-making? If future endangered species risk assessments are pe rformed without these data, the Agency would have to presume risk to non-target terrestrial plants from use of methiocarb. Therefore, use of methiocarb and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agen cy and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for methiocarb that are unnecessarily

severe.

Guideline Number: 850.4400 Aquatic Plant Growth Tier I Study (Vascular Aquatic Plant) Rationale for Requiring the Data Aquatic (both vascular and non-vascular species) toxicity studies and associated risk analysis of plants are required for registration of pesticides with outdoor u ses (CFR Part 158). There are currently no data
available to determine the levels of methiocarb that could result in effects to aquatic vascular plants. Therefore, effects on non-target aquatic plants cannot be discounted, and the level of risk is unknown. Therefore, an aquatic vascular plant study is re quired as specified in 40 CFR Part 158 (OPPTS Guideline 850.4400). Practical Utility of the Data

How will the data be used? Data from Tier I aquatic plant toxicity studies will be used to estimate potential risks to aquatic plants
associated with uses of methiocarb. The data will reduce uncertainties associated with the current risk assessment for plants and will improve our understanding of the potential effects of methiocarb on aquatic plants. Because plants form the basis of most habitats and significantly contribute to overall environmental quality, a solid understanding of the potential risks to aquatic plants is essential for sound environmental management. The data will also be used in determining whether a “may affect” to Federally-listed threatened and endangered speci es is likely under the Endangered Species Act.

Additionally, the need for labeling language to mitig ate effects on non-target aquatic plant species is unknown. Results of this study woul d be used to determine if surface water exposure concentrations, due to run-off, are below levels of concern at the current label rates and to identify what, if any, label language is needed to mitigate identified risks.

How could the data impact the Agency’s future decision-making? Without aquatic plant growth data for methiocarb, th e Agency cannot determine the levels of methiocarb that result in effects to vascular aquatic plants. Un til these data are available, the registration decision will
be based on the information listed on the label. The l ack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for methiocarb which may otherwi se be avoided, or which are unnecessarily severe.

Guideline Number: 850.5400 Aquatic Plant Growth Tier I Study (Non-vascular Aquatic Plant) Rationale for Requiring the Data



### -68 of 69-Aquatic (both vascular and non-vascular species) toxicity studies and associated risk analysis of plants are required for registration of pesticides with outdoor uses (40 CFR Part 158). There are currently no data
available to determine the levels of methiocarb that could result in effects to aquatic non-vascular plants. Therefore, effects on non-target aquatic plants cannot be discounted, and the level of risk is unknown. Therefore, an aquatic non-vascular plant study is required as specified in 40 CFR Part 158 (OPPTS Guideline 850.5400). Practical Utility of the Data

How will the data be used? Data from Tier I aquatic plant toxicity studies will be used to estimate potential risks to aquatic plants from methiocarb exposure. The data will reduce uncertainti es associated with the curr ent risk assessment for plants and will improve our understa nding of the potential effects of methiocarb use on aquatic plants. Because plants form the basis of most habitats and significantly contribute to overall environmental quality, a solid understanding of the potential risks to aquatic plants is essential for sound environmental management. The data will also be used in dete rmining whether a “may affect” to Federally-listed threatened and endangered species is likely under the Endangered Species Act.

Additionally, the need for labeling language to mitig ate effects on non-target aquatic plant species is unknown. Results of this study woul d be used to determine if surface water exposure concentrations, due to run-off, are below levels of concern at the current label rates and to identify what, if any, label language is needed to mitigate identified risks.

How could the data impact the Agency’s future decision-making? Without aquatic plant growth data for methiocarb, th e Agency cannot determine the levels of methiocarb that result in effects to non-vascular aquatic plants. Until these data are available, the registration decision
will be based on the information listed on the label. The lack of these data will limit the flexibility the Agency and registrants have in coming into complian ce with the Endangered Species Act, and could result in use restrictions for methiocarb which may othe rwise be avoided, or which are unnecessarily severe.



### -69 of 69-