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OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

August 3, 2015

PC Codes: 034801, 079801

MEMORANDUM DP Barcodes: 427810, 427924

SUBJECT: Registration Review: Preliminary Problem Formulation for Environmental Fate, 

Ecological Risk, Endangered Species, and Human Health Drinking Water 

Exposure Assessments for Ferbam and Thiram

FROM: Elyssa Arnold, Biologist

Ron Parker, Senior Environmental Engineer

Environmental Risk Branch 2

Environmental Fate and Effects Division (7507P)

REVIEWED Melissa Panger, Senior Science Advisor

BY: James Lin, Environmental Engineer

Environmental Risk Branch 2

Environmental Fate and Effects Division (7507P)

THROUGH: Brian Anderson, Branch Chief

Environmental Risk Branch 2

Environmental Fate and Effects Division (7507P)

TO: Khue Nguyen, Chemical Review Manager

Tom Moriarty, Team Leader

Neil Anderson, Branch Chief

Risk Management and Implementation Branch 1

Wilhelmena Livingston, Chemical Review Manager

Kevin Costello, Branch Chief

Risk Management and Implementation Branch 4

Pesticide Re-evaluation Division (7508P)
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Table of Contents

1. Executive Summary................................................................................................................ 3

2. Introduction............................................................................................................................. 4

3. Use Characterization............................................................................................................... 5

4. Conclusions from Previous Risk Assessments....................................................................... 8

4.1. Ecological Risk Assessment............................................................................................. 8

4.2. Drinking Water Exposure Assessments......................................................................... 10

4.3. Clean Water Act Programs............................................................................................. 10

5. Environmental Fate and Transport........................................................................................ 10

5.1. Transformation Products................................................................................................ 13

6. Receptors............................................................................................................................... 17

6.1. Effects to Aquatic Organisms ........................................................................................ 17

6.2. Effects to Terrestrial Organisms .................................................................................... 19

6.3. Ecological Incidents....................................................................................................... 21

7. Exposure Pathways of Concern ............................................................................................ 22

8. Analysis Plan ........................................................................................................................ 22

8.1. Stressors of Concern....................................................................................................... 22

8.2. Measures of Exposure .................................................................................................... 22

8.3. Measures of Effect ......................................................................................................... 23

8.4. Endangered Species Assessments.................................................................................. 23

8.5. Endocrine Disruptor Screening Program ....................................................................... 24

9. Preliminary Identification of Data Gaps............................................................................... 24

9.1. Environmental Fate ........................................................................................................ 24

9.2. Effects............................................................................................................................. 26

10. References.......................................................................................................................... 35

10.1. Submitted Environmental Fate Studies ...................................................................... 36

10.2. Submitted Ecological Toxicity Studies ...................................................................... 42

Appendix A. SIP Modeling Results.............................................................................................. 45

Appendix B. STIR Modeling Results........................................................................................... 46

Appendix C. Summary of Ferbam and Thiram Fate and Transport Data..................................... 47

Appendix D. Ziram, Thiram, and Ferbam Ecotoxicity Data ........................................................ 52
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1. Executive Summary

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

formulation for the ecological risk, environmental fate, endangered species, and drinking water 

assessments to be conducted as part of the registration review of the fungicides ferbam (PC 

034801) and thiram (PC 079801). The problem formulation describes the methods planned to be 

used during the completion of drinking water and ecological risk assessments in support of 

registration review and provides an overview of the environmental fate, ecological effects,

potential risks associated with the use, and uncertainties unique to the risk assessment of ferbam 

and thiram. This document also identifies additional studies that would be beneficial to the 

conduct of an ecological risk assessment. Ferbam and thiram are being assessed together because 

ferbam rapidly degrades to the more persistent thiram. Thiram is also the major degradate of 

concern for ziram, which is another dimethyldithiocarbamate fungicide. The problem 

formulation for ziram can be found under DP 427965 (USEPA, 2015).

The ferbam Reregistration Eligibility Decision (RED) was completed in 2005 and the thiram

RED was completed in 2004. The ferbam and thiram REDs concluded that there was risk of 

acute and chronic adverse effects to aquatic organisms and risk of chronic adverse effects to

birds, and mammals. Acute risks to birds and mammals were considered unlikely due to thiram’s 

use as a wildlife repellent for mammals. Data submitted following the REDs will be incorporated 

into the registration review risk assessment.

The following are the needed data and uncertainties for ferbam and thiram:

Data Needs

• Environmental Fate and Transport Data

o None

• Ecotoxicity Data – Studies to be conducted with thiram only

o Aquatic animal studies

 OCSPP 850.1350: Mysid chronic toxicity 

 OCSPP 850.1400: Estuarine/marine fish early-life stage toxicity

o Aquatic plant studies

 OCSPP 850.4500: Algal toxicity, studies with freshwater diatom Navicula 

pelliculosa and marine diatom Skeletonema costatum

 OCSPP 850.4550: Cyanobacteria toxicity

o Avian studies

 OCSPP 850.2100: Avian acute toxicity, passerine species

o Terrestrial invertebrate studies1

 Non-guideline (Tier 1): Honey bee adult acute oral toxicity

 Non-guideline (Tier 1): Honey bee larvae acute toxicity

 Non-guideline (Tier 1): Honey bee adult chronic oral toxicity

 1 Tier 2 and 3 studies are conditional on the outcome of the screening-level assessment where acute and/or chronic 

risk levels of concern have been exceeded for terrestrial invertebrates based on Tier I studies of individual bees.
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 Non-guideline (Tier 1): Honey bee larvae chronic toxicity

 Non-guideline (Tier 2): Semi-field testing for pollinators (tunnel or colony 

feeding studies)

 Non-guideline (Tier 2): Field trial of residues in pollen and nectar

 OCSPP 850.3040 (Tier 3): Field testing for pollinators

o Terrestrial plant studies

 OCSPP 4100: Seedling Emergence

 OCSPP 4150: Vegetative Vigor

Other Major Uncertainties

For many of the labeled uses of thiram, the labels do not specify the annual maximum 

application rate, number of applications, or minimum retreatment intervals when multiple 

applications are permitted. Absence of such information on the labels may result in conservative 

assumptions for modeling of use patterns in the registration review risk assessment.

The only Section 3 ferbam label does not specify the minimum retreatment interval for most uses 

and presents conflicting information for application rate and application method for some uses. 

Additionally, the treated area permitted at the spot treatment rate for cranberries is not defined. 

These label uncertainties may result in conservative assumptions for exposure modeling.

2. Introduction

Ferbam, ferric dimethyldithiocarbamate, and thiram, tetramethyl thiuram disulfide, are 

dimethyldithiocarbamate fungicides. These fungicides are non-systemic and act by concomitant 

inhibition of spore germination and mycelial growth through multi-site interference of enzyme 

processes associated with respiration. As an animal repellent, thiram creates a taste aversion to 

deter feeding by rabbits, deer, and rodents.

Ferbam is registered for foliar use on food crops and ornamentals. There is one active Section 3 

registration, a water dispersible granule formulation, and one active special local needs label for 

ferbam in the United States. There are no registered co-formulated products with ferbam.

Thiram is registered as a foliar spray, seed protectant, and animal repellent. There are 19 active 

Section 3 registrations and six active special local needs labels for thiram in the United States. 

Thiram seed treatments are co-formulated with tebuconazole, ipconazole, triticonazole, carboxin, 

metalaxyl, and imidacloprid. No products labeled for foliar applications are co-formulated.

Thiram formulations include dust, dry flowable, emulsifiable concentrate, flowable concentrate, 

ready-to-use, suspension concentrate, and wettable powder.

EFED evaluated the most recent ecological risk assessments for ferbam and thiram in association 

with the updated toxicity, exposure, and usage information to determine if sufficient data are 

available and if further updates are needed to support registration review. The most recent risk 
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assessments were the 2004 EFED RED Chapters (USEPA, 2004a, 2004b). In addition, EFED

considered the latest Agency science policies and risk assessment methodologies. 

3. Use Characterization

Ferbam is registered for use via chemigation or ground spray on apples, pears, citrus, nectarines, 

peaches, and cranberries. A special local needs label is registered for use on mangoes in Florida.

The primary uses for ferbam are on grapefruit (5-10% of crop treated) and oranges (<2.5% crop 

treated), at approximately 20,000 lbs a.i./yr for each crop from 2004-2012 (USEPA, 2014a). 

Thiram is registered for foliar use on fruit trees, strawberries, vegetation surrounding airport 

landing fields, ornamentals, and golf course turf. It can be applied through chemigation, aerial

(peaches and strawberries, only) and ground spray, and dips for transplants, bulbs, and tubers. It 

is also used as a seed protectant for a variety of vegetables, grains, cotton, ornamentals, and other 

seeds, and as an animal repellent to protect ornamentals, nursery stock, and non-bearing vines 

and fruit trees from damage by rabbits, rodents, and deer. Vegetation surrounding airport 

runways can be treated to deter deer from moving onto the runways. The primary foliar 

agricultural uses for thiram are on apples (<2.5-10% of crop treated) and strawberries (20-30% 

of crop treated), at approximately 50,000 lbs a.i./yr for each crop (USEPA, 2014b). The primary 

seed treatment uses for thiram are on cotton (5-15% of crop treated), soybeans (<2.5-5% of crop 

treated), and wheat (<2.5% of crop treated), at approximately 6,000, 40,000, and 20,000 lbs 

a.i./yr, respectively from 2004-2012 (USEPA, 2014b). No usage data is available for nonagricultural use sites such as turf and ornamentals.

Table 1 and Table 2 list the maximum use patterns for the registered uses of ferbam and thiram, 

respectively. EFED will use application scenarios that result in maximum exposure scenarios for 

a given use for the risk assessment. For seed treatments with thiram, maximum seeding rates for 

each crop in the T-REX model will be assumed unless alternative seeding rates are specified on 

the label. For labels that do not include a maximum annual or seasonal application rate, 

maximum number of applications, or minimum retreatment interval, conservative assumptions 

will be made as illustrated in the following examples:

• A maximum single application rate is specified with a re-application interval of 7 days 

without specifying a maximum annual rate may result in an assumption of 52 

applications with 7-day intervals;

• A label that does not specify an application interval may result in assumptions of short 

application intervals such as 1- or 3-day intervals.

Table 1. Maximum Use Patterns for Current Uses of Ferbam

Use

Max 

Single 

App. Rate

(lbs a.i./A)

Max App. 

Rate per 

CC

(lbs a.i./A)

Max # 

of App. 

per CC

Max App. 

Rate per 

Year

(lbs a.i./A)

Max # of 

App. per 

Year

Min 

Retreatment 

Interval 

(days)

Application 

Methods

Apple 3.5 NS NS 10.5 3 NS Chemigation & 

ground spray
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Use

Max 

Single 

App. Rate

(lbs a.i./A)

Max App. 

Rate per 

CC

(lbs a.i./A)

Max # 

of App. 

per CC

Max App. 

Rate per 

Year

(lbs a.i./A)

Max # of 

App. per 

Year

Min 

Retreatment 

Interval 

(days)

Application 

Methods

Citrus 6 NS NS 18 3 NS Chemigation & 

ground spray

Cranberry

4.56 NS NS 30 5 14 Chemigation & 

ground spray

2264 1 NS NS 2264 1 NA Spot treatment 

to 1 sq. foot

Peach 3.4 NS NS 10.2 3 NS Chemigation & 

ground spray

Mango 3.0 NS NS 30 10 10 Ground spray

Nectarine 3.4 NS NS 10.2 3 NS Chemigation & 

ground spray

Pear 3.5 NS NS 10.5 3 NS Chemigation & 

ground spray

NS=Not Specified; App.=Applications; CC=Crop Cycle 1 Equivalent to 0.05 lbs a.i./ft2

. The label does not restrict the total number of spot treatments per acre.

Table 2. Maximum Use Patterns for Current Uses of Thiram

Use

Max 

Single 

App. Rate

(lbs a.i./A)

Max App.

Rate per 

CC

(lbs a.i./A)

Max # 

of App. 

per CC

Max App.

Rate per 

Year

(lbs a.i./A)

Max # of 

App. per 

Year

Min 

Retreatment 

Interval 

(days)

Application 

Methods

Vegetation 

surrounding 

airports/ 

landing 

fields

32.7 NS NS NS NS NS Spray & 

brush-on

Fruit trees 43.5 NS NS NS NS NS

Hand-held 

spray wand & 

brush-on

Golf course 

turf 16.3 NA NA NS NS 14 Spray & sprinkler

Nursery 

stock & 

ornamentals

43.5 NS NS NS NS NS

Hand-held 

spray wand & 

brush-on

Peach 2.63 15.9 6 NS NS 7 Aerial & 

ground spray

Strawberry 3.3 NS NS 16.5 5 10 Aerial & 

2.96 NS NS 29.6 12 10 ground spray

Alfalfa, barley, beans, beets, broccoli, Brussels sprouts, buckwheat, cabbage, canola, carrot, 

castor bean, cauliflower, celery, Swiss chard, chicory, clover, collards, conifers, coriander, 

field corn, sweet corn, cowpeas, cucumber, eggplant, endive, flax, grass grown for forage or 

seed, kale, kohlrabi, lentils, lettuce, melons, millet, mustard, oats, okra, onion, ornamentals, 

peanuts, peas, pepper, pumpkin, radish, rice, rye, safflower, sesame, small seeded legumes, 

sorghum, soybeans, spinach, squash, sugar beets, sunflower, tomato, triticale, turnip, 

vegetables, vetch, wheat

Seed treatment

NS=Not Specified; App.=Applications; CC=Crop Cycle

Maps of estimated annual use for ferbam and thiram in 2012 are presented in Figures 1 and 2, 

respectively.
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Figure 1. Estimated Agricultural Use for Ferbam (USGS, 2012)
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Figure 2. Estimated Agricultural Use for Thiram (USGS, 2012)

4. Conclusions from Previous Risk Assessments

4.1. Ecological Risk Assessment 

The most recent ecological risk assessments for thiram and ferbam are the 2004 EFED RED 

chapters (USEPA, 2004a, 2004b). The REDs for both chemicals concluded that there was risk of 

acute and chronic adverse effects to aquatic organisms and risk of chronic adverse effects to 
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birds, and mammals. Acute risks to birds and mammals were considered unlikely due to thiram’s 

use as a wildlife repellent. While chronic aquatic risk was considered likely, no chronic aquatic 

toxicity data were available at the time of the RED assessments. Figure 3 and Table 3

summarize the potential risks identified in previous assessments and the supporting evidence.

Figure 3. Graphic Summary of Potential Risks of Current Uses

Table 3. Evidence of Risk to Taxonomic Groups from Thiram and Ferbam Uses

Predominant Evidence of Negligible Risk Predominant Evidence of Risk

None Mammals and birds: Acute and chronic risk LOC 

exceedances for listed and non-listed species from a 

single application. Acute risk is uncertain due to the 

repellent nature of the chemicals, but chronic risk is 

considered likely.

Fish and aquatic invertebrates: Acute risk LOC 

exceedances for listed and non-listed freshwater fish, 

freshwater invertebrates, and estuarine/marine 

invertebrates. No chronic toxicity data available.

Limited Evidence of Negligible Risk Limited Evidence of Risk

Aquatic plants: No LOC exceedances for green algae or 

duckweed. Toxicity data not available for other aquatic 

plant species.

None

Terrestrial plants: No toxicity data available. No 

incidents reported.

Terrestrial invertebrates: Thiram and ferbam are

practically non-toxic to adult honey bees on an acute 

contact exposure basis. No other toxicity data available. 
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4.2. Drinking Water Exposure Assessments

A drinking water exposure assessment for thiram was completed as part of the RED in 2004

(USEPA, 2004a). Maximum Tier 2 exposure estimates for the residues of concern in surface 

water were 180 μg/L (1-in-10-year peak), 4.3 μg/L (1-in-10-year annual mean), and 3.0 μg/L

(cancer) using the PRZM and EXAMS models. For ground water, screening level exposure

estimates were 0.84 μg/L for both acute and chronic exposure using the SCI-GROW model.

A drinking water exposure assessment for ferbam was completed as part of the RED in 2004. 

The assessment calculated thiram concentrations in drinking water resulting from ferbam 

applications due to the rapid degradation of ferbam to thiram. The estimated residues of concern 

in surface water were 81 μg/L 1-in-10-year peak) and 2.5 μg/L (1-in-10-year annual mean). The 

exposure estimates for ground water were 0.02 μg/L for both acute and chronic exposure using 

the SCI-GROW model.

4.3. Clean Water Act Programs

Thiram and ferbam are not identified as a cause of impairment for any water bodies listed as 

impaired under section 303(d) of the Clean Water Act.

2 No Total Maximum Daily Load 

(TMDL) criteria have been developed for thiram or ferbam.

3 Aquatic life benchmarks have been 

established for thiram and are available at 

http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm; no benchmarks have 

been established for ferbam. Any data submitted or otherwise located as part of the registration 

review process may be used to update aquatic life benchmarks if applicable. 

 

5. Environmental Fate and Transport

The available environmental fate data are summarized for both ferbam and thiram below. The 

risk assessments for both thiram and ferbam will focus on exposure to thiram given the rapid 

transformation of ferbam to thiram. Therefore, thiram data will be used in both the ferbam and 

thiram risk assessments. Ferbam studies also provide useful information on thiram because of the 

rapid degradation of ferbam to thiram.

Ferbam is a short lived chemical that degrades rapidly (up to 31 minutes) via hydrolysis, 

photolysis and aerobic soil metabolism to thiram, the major degrade of ferbam. Ferbam 

hydrolyzed with half-lives of less than 12.1 minutes at pH 5 to 9. In aqueous photolysis, soil

photolysis, and aerobic soil metabolism studies, ferbam degraded too quickly to allow for the 

measurement of the degradation rate. Thiram was the major degradate in all degradation 

pathways. There are no acceptable soil adsorption and mobility data for ferbam. EFED 

acknowledges that it is difficult to conduct a scientifically sound batch equilibrium study for 

 2 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

3 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant 

_group_name=PESTICIDES
Page 11 of 60

ferbam since it is very unstable under hydrolytic and aerobic conditions. There is little potential 

for ferbam to leach into groundwater due to its rapid degradation rate.

Thiram is moderately persistent and is degraded by a combination of abiotic and biotic processes 

in soil and water to produce non-persistent degradates such as COS, CS2 and CO2. Thiram is 

essentially immobile (Koc = 2245 to 24526 in 4 soils). The chemical has a potential to reach 

surface water through runoff via erosion or spray drift. 

Hydrolysis, photodegradation, and aerobic soil metabolism are the main degradation processes 

for thiram. Observed half-lives are generally less than 18 days under the expected use conditions

and environmentally relevant pHs. When exposed to sunlight, thiram is expected to degrade 

within approximately a day via photolysis. When exposed to water, thiram degradation is pH 

dependent with half-lives of several days to several weeks at pH 7, and much slower at pH 5 

(half-life of approximately 2 to 6 months). Thiram degrades relatively rapidly via microbial 

metabolism in soil and water with half-lives of approximately 2 weeks in soil and 2 days in water 

under aerobic conditions. Thiram is more persistent under anaerobic conditions with half-lives of 

approximately 4 to 40 days. 

Thiram residues appear to have low mobility in the environment with Koc values that range from 

approximately 2000 to 25,000 L/kg. 

Terrestrial field dissipation studies are consistent with the laboratory data. In studies conducted 

in California, thiram (SpotreteTM 75 WDG), broadcast applied eight times as a spray, at a nominal 

application rate of 10.3 lbs a.i./A/application, dissipated with half-lives of 14 and 27 days for 

bare-ground and turf plots of sandy loam soil (pH 8.2 to 9.6), respectively. In studies conducted 

in North Carolina, Thiram (Spotrete® 75WDG), broadcast applied eight times as a spray at a 

nominal application rate of 10.3 lb a.i./A/application, dissipated with half-lives of 36 and 62 days 

on a bare ground plot of sand soil (pH 4.1 to 4.7) and a turf plot of loamy sand soil (pH 4.4 to 

4.5), respectively. 

Tables 4 and 5 below summarize the chemical and environmental fate properties of ferbam and 

thiram, respectively. A detailed description of the available data can be found in Appendix C.

Table 4. Chemical Properties and Environmental Fate Parameters of Ferbam

Parameter Value Description Source

Selected Physical/Chemical Parameters

Molecular mass (molecular formula) 416.49 g/mol 

(C9H18FeN3S6) NA (Calculated)

Vapor pressure (25°C) <2.05 x 10-6 Pa

1.54 x 10-8 mm Hg

Low potential for 

volatilization MRID 00262064

Aqueous solubility (20°C) 130 mg/L Soluble PPDB

Henry’s Law Constant (20°C) 1.58 x 10-8 Low potential for 

volatilization PPDB

Log octanol-to-water partition coefficient

(log KOW) -1.6 Moderately hydrophilic MRID 40600608
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Parameter Value Description Source

Persistence

Hydrolysis half-life (25°C)

pH 5: 12 min

pH 7: 8 min

pH 9: <0.2 min

Very rapid degradation 

pathway MRID 44071801

Aqueous photolysis half-life (25°C) <1 hr Hydrolyzes too rapidly

to measure MRID 43999801

Soil photolysis half-life (25°C) <1 hr Hydrolyzes too rapidly

to measure MRID 45742501

Aerobic soil metabolism half-life (25°C) <1 hr Hydrolyzes too rapidly

to measure MRID 44368901

Anaerobic soil metabolism half-life (25°C) NA Hydrolyzes too rapidly

to measure MRID 44565305

Aerobic aquatic metabolism half-life 

(25°C) NA NA NA

Anaerobic aquatic metabolism half-life 

(25°C) NA NA NA

Mobility

Mobility in Soils NA

Rapid degradation 

prevents measurement of 

mobility

NA

Field Dissipation

Terrestrial field dissipation half-life; 

leaching depth NA NA NA

NA: Not Available

Table 5. Chemical Properties and Environmental Fate Parameters of Thiram

Parameter Value Description Source

Selected Physical/Chemical Parameters

Molecular mass (molecular formula) 240.43 g/mol (C6H12N2S4) (Calculated)

Vapor pressure (25°C) 2.3 mPa

1.72 x 10-5 Torr

Low potential for 

volatilization

PPDB

USEPA, 2004a

Aqueous solubility (20°C) 16.5 mg/L Soluble PPDB

Henry’s Law Constant (20°C) 3.3 x 10-7 Pa-m3

/mol

1.4 x 10-5 (dimensionless)

Low potential for 

volatilization (Calculated)

Log octanol-to-water partition 

coefficient (log KOW) 1.73 Moderately hydrophobic PPDB

Persistence
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Parameter Value Description Source

Hydrolysis half-life (days)

(25°C)

pH 5: 169 d

pH 7: 17.9 d

pH 9: 6.9 d

pH 5: 68.5 d

pH 7: 3.5 d

pH 9: 6.9 hr

Slow to very rapid 

degradation pathway 

depending on pH

MRID 45714101

MRID 41840601

Aqueous photolysis half-life (days) 

(pH 5 buffer, 25°C)

10.4 hr

7.2 hr

May photolyze in clear, 

shallow waters

MRID 41753801

MRID 45651201

Soil photolysis half-life (25°C) 17.3 hr

43.2 hr (dark controls) Effects soil surface only MRID 45724501

Aerobic soil metabolism half-life 

(25°C)

17.2 d 

2.09 d (non-linear 

regression)

Moderately rapid 

degradation pathway MRID 43734901

Anaerobic soil metabolism half-life 

(25°C) NA NA NA

Aerobic aquatic metabolism half-life 

(25°C)

1.5 d (pond water)

2.1 d (river water)

Rapid degradation 

pathway in water column MRID 45243401

Anaerobic aquatic metabolism halflife (25°C) 43.1 d Not a rapid degradation 

pathway MRID 43628501

Mobility

Mobility in Soils Koc = 2245 to 24526 in 4 

soils Slightly to hardly mobile MRID 43787501

Maximum volatile concentration 

(23°C)

313 μg/m3 (24 hrs posttreatment)

(35% volatilized by 4 d 

post-treatment)

NA MRID 43754001

Field Dissipation

Terrestrial field dissipation half-life

North Carolina

36 d (bare ground)

62.5 d (turfed sandy loam)

NA MRID 44724502

NA: Not Available

5.1. Transformation Products

Ferbam degrades rapidly via hydrolysis, photodegradation, and aerobic soil metabolism. It has a 

very short half-life, ranging from too low to assess to 31 minutes under abiotic and biotic 

(natural) degradative processes. Rapid degradative processes of ferbam suggest that the chemical 

would not persist in the environment. Ferbam degradates are detailed in Table 6. The major 

transformation product is tetramethylthiuram disulfide (TMTD, also commonly known as 

thiram), which is moderately persistent in soil or water. Theoretically, for every two ferbam 

molecules, three thiram molecules could potentially be formed (see Figure 4). Some of the 

environmental fate studies indicated almost quantitative formation of thiram and for previous

assessments, a quantitative formation was assumed. This approach will also be used for the 

registration review risk assessment, see Section 8 for additional details.
Page 14 of 60

Degradates of thiram include dimethyldithiocarbamate anion (DTC), carbonyl sulfide (COS), 

carbon disulfide (CS2), and carbon dioxide (CO2). There are no major (≥10%) non-volatile 

degradates. Thiram degradates are detailed in Table 7.

Figure 4. Conversion from Ferbam to Thiram
Page 15 of 60

Table 6. Ferbam and its Major Environmental Degradates 

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR (day)

Final 

%AR 

(study 

length)

PARENT

Parent Ferbam

(PC Code:

034801)

ferric dimethyldithiocarbamate

CAS No.: 14484-64-1

Formula: C9H18FeN3S6

MW: 416.49 g/mol

MAJOR TRANSFORMATION PRODUCTS

Degradate

Thiram

(PC Code:

079801)

tetramethylthiram disulfide

CAS No.: 137-26-8

Formula: C6H12N2S4

MW: 240.43 g/mol

Hydrolysis and 

aqueous 

photolysis

44071801

63.3% (1 day)

1.1% (7 days)

0.5% (15 days)

15 days

Aerobic soil 43999802

77.9% (0 days)

49.9% (7 days)

26.3% (150 days)

150 days

Anaerobic soil 44565305 33.8% (0 days)

50% (184 days) 364 days

CS2 carbon disulfide Hydrolysis and 

aqueous 

photolysis

44071801 44.6% (14 days) 15 days

Soil photolysis 43999802 44.6% (15 days) 15 days

CO2 carbon dioxide Hydrolysis and 

aqueous 

photolysis

44071801 28.6% (14 days) 15 days

Soil Photolysis 43999802 28.6% (15 days) 15 days
Page 16 of 60

Table 7. Thiram and its Major Environmental Degradates 

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

PARENT

Thiram tetramethylthiram disulfide

CAS No.: 137-26-8

Formula: C6H12N2S4

MW: 240.43 g/mol

MAJOR TRANSFORMATION PRODUCTS

thiosulfinic acid

Hydrolysis pH 7 45714101 27.2% (30 days) 30 days

Soil photolysis 45724501 82.5% (0 days)

17.2% (15 days) 15 days

sodium dimethyl 

dithiocarbamate Hydrolysis pH 7 45714101 12% (12 days)

0.0% (30 days) 30 days

sodium dimethyl 

dithiocarbamate +

thiosulfenic acid

Hydrolysis pH 9 45714101 66.8% (13 days)

66.8% (34 days) 34 days

CO2 carbon dioxide Aerobic soil 43734901 9% (4 days)

74.9% (205 days) 205 days

CS2 carbon disulfide

Hydrolysis pH 9 

& Aqueous 

photolysis

43999801 35% (30 days) 30 days

Anaerobic 

Aquatic 43628501 17% (7 days)
Page 17 of 60

6. Receptors

Table 8 and Table 10 provide a summary of the aquatic and terrestrial taxonomic groups, 

respectively, and most sensitive surrogate species tested to characterize the potential acute and 

chronic ecological effects of thiram. Tables 9 and 11 provide this same information, as available,

for ferbam. A complete list of the ecotoxicity data available for thiram, ferbam, and the related 

dimethyldithiocarbamate ziram can be found in Appendix D.

6.1. Effects to Aquatic Organisms

Thiram and ferbam are highly to very highly toxic to freshwater and estuarine/marine fish and 

aquatic invertebrates on an acute exposure basis. Chronic effects on growth and reproduction are 

seen consistently across tested aquatic species with NOAECs of approximately 0.002 to 0.02 mg 

a.i./L. A mysid chronic study conducted with ferbam failed to establish a NOAEC (<0.0012 mg 

a.i./L). Effects of thiram on biomass and frond number were observed on tested non-vascular and 

vascular aquatic plant species, respectively.

Additionally, a supplemental mesocosm study with Thiram 80WG was designed to simulate 

effects of spray drift to a freshwater ecosystem (MRID 46249304). Phytoplankton taxa 

abundance, diversity, evenness, and similarity were significantly reduced at 0.32 mg a.i./L 

(NOAEC = 0.10 mg a.i./L). Zooplankton taxa abundance was significantly reduced at 0.010 mg 

a.i./L (NOAEC = 0.0032 mg a.i./L) and zooplankton community similarity was affected at the 

lowest tested concentration (NOAEC <0.001). Macrozoobenthic community similarity was 

impacted at 0.10 mg a.i./L (NOAEC = 0.032 mg a.i./L). No treatment-related effects were 

observed for the emergent insect community up to the highest concentration tested, 1.0 mg a.i./L. 

Population densities of the aquatic snail Gyraulus albus and the leech Helobdella stagnalis were 

reduced at 0.10 mg a.i./L (NOAEC = 0.032 mg a.i./L).

Table 8. Summary of Most Sensitive Toxicity Endpoints for Aquatic Organisms Exposed to Thiram

Taxonomic 

Group

Study 

Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured mg a.i./L

(Acute Toxicity Category or 

Most Sensitive Endpoints)

MRID and 

Study 

Classification

Aquatic Vertebrates

Freshwater 

fish 

Acute TGAI

(80%)

Harlequin Fish 

(Rasbora 

heteromorpha)

96-hr LC50 = 0.007

(Very highly toxic)

05020144

Supplemental

Chronic 

(Full Life 

Cycle)

TGAI

(98.7%)

Fathead minnow 

(Pimephales 

promelas)

210-d NOAEC = 0.0011

210-d LOAEC = 0.0022

(Spawning frequency, egg 

production, time to hatch, 4-

week survival)

47824101

Acceptable

Estuarine/

marine fish

Acute TGAI

(98.3%)

Sheepshead Minnow 

(Cyprinodon 

variegatus)

96-hr LC50 = 0.54

(Highly toxic)

42514401

Acceptable

Chronic No data available
Page 18 of 60

Taxonomic 

Group

Study 

Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured mg a.i./L

(Acute Toxicity Category or 

Most Sensitive Endpoints)

MRID and 

Study 

Classification

Aquatic Invertebrates

Freshwater 

invertebrates

Acute TGAI

(98.0%)

Water Flea

(Daphnia magna)

48-hr EC50 = 0.21

(Highly toxic)

00164662

Acceptable

Chronic TGAI

(98.7%) Water Flea

21-d NOAEC = 0.020

21-d LOAEC = 0.040

(Dry weight, clinical signs of 

toxicity)

47495001

Acceptable

Estuarine/

marine 

invertebrates

Acute

(Larval 

development)

TGAI

(98.3%)

Pacific Oyster 

(Crassostrea gigas)

48-hr EC50 = 0.0047

(Very highly toxic)

42488301

Acceptable

Acute TGAI

(98.3%)

Mysid Shrimp 

(Mysidopsis bahia)

96-hr LC50 = 0.00336

(Very highly toxic)

42488302 

Acceptable

Chronic No data available

Aquatic Plants

Aquatic 

plants and 

algae

Vascular TGAI

(98.7%)

Duckweed

(Lemna gibba)

7-d NOAEC < 0.057

7-d EC50 = 1.6

(Frond number)

45441202

Acceptable

NonvascularTGAI

(99.0%)

Green Algae 

(Pseudokirchneriella 

subcapitata)

120-hr EC05 = 0.003

120-hr EC50 = 0.14

(Biomass)

44086101, 

44086001

Acceptable

Table 9. Summary of Most Sensitive Toxicity Endpoints for Aquatic Organisms Exposed to Ferbam

Taxonomic 

Group

Study 

Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured mg a.i./L

(Acute Toxicity Category or 

Most Sensitive Endpoints)

MRID and 

Study 

Classification

Aquatic Vertebrates

Freshwater 

fish 

Acute

TGAI

(% 

unknown)

Carp 

(Cyprinus carpio)

48-hr LC50 = 0.09

(Very highly toxic)

05001997

Supplemental

Chronic No data available

Estuarine/

marine fish

Acute TGAI

(76%)

Longnose killifish 

(Fundulus similis)

96-hr LC50 = 0.80

(Highly toxic)

40228401

Supplemental

Chronic No data available

Aquatic Invertebrates

Freshwater 

invertebrates

Acute No data available

Chronic No data available

Estuarine/

marine 

invertebrates

Acute

(Shell 

Deposition)

TGAI

(76%)

Eastern Oyster 

(Crassostrea 

virginica)

96-hr EC50 = 0.052

(Very highly toxic)

40228401

Supplemental

Acute TGAI

(76%)

Pink Shrimp 

(Penaeus duorarum)

48-hr LC50 > 40

(Slightly toxic)

40228401

Supplemental

Chronic TGAI

(97.6%)

Mysid Shrimp 

(Americamysis 

bahia)

28-d NOAEC < 0.0012

28-d LOAEC = 0.0012

F0 body length

47784401

Supplemental
Page 19 of 60

Taxonomic 

Group

Study 

Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured mg a.i./L

(Acute Toxicity Category or 

Most Sensitive Endpoints)

MRID and 

Study 

Classification

Aquatic Plants

Aquatic 

plants and 

algae

Vascular No data available

Nonvascular No data available

6.2. Effects to Terrestrial Organisms

Thiram and ferbam are slightly to moderately toxic to birds and mammals on an acute exposure 

basis. In chronic studies, the most sensitive endpoints for birds were measures of reproductive 

output and viability while the most sensitive endpoints for mammals were growth related. 

Toxicity studies on birds may provide some insight into whether the repellency properties for 

mammals also apply to birds. The acute oral and sub-acute dietary studies were conducted by 

federal laboratories in the 1970s and 1980s, and the associated food consumption and body 

weight data are not available. An avian reproduction study on bobwhite quail showed reductions 

in food consumption and hen bodyweight at 2500 ppm, the highest concentration tested (MRID 

43612502). Food consumption and bodyweight were not affected in the avian reproduction study 

on mallard duck, up to 40 ppm (MRID 45441201). These studies also demonstrated that the 

bobwhite quail and mallard duck will ingest a sufficient amount of treated feed to cause adverse 

reproductive effects. 

Feeding choice studies with bobwhite quail and mallard ducks have demonstrated that while 

birds prefer untreated feed to feed treated with thiram, they will still consume the treated feed in 

quantities shown to cause adverse reproductive effects (MRIDs 43612505, 43612506). Also, 

multiple field studies have demonstrated that granivorous birds will consume seeds treated with 

thiram. Dhinsa et al. (1991) demonstrated that thiram did not effectively repel the common house 

crow from eating planted sunflower seeds treated with thiram. The study compared bird 

consumption of seek in plots of untreated sunflower seeds to plots of thiram treated sunflower 

seeds. The results showed no significant difference between seed consumption between the 

untreated and treated plots. Furthermore, a Danish study found that more than half of the daily 

energy intake of pink-footed geese (Anser brachyrynchus) could be obtained from foraging in 

newly-sown fields. Also based on observations in fields sown with thiram-treated peas, the study 

predicted that individuals consumed enough pesticide to elicit effects on reproduction in less 

than an hour (Madsen, 1996). Additionally, the European union risk assessment (Appendum to 

Monogram, November 2, 2002; Page 9-3) for thiram references a study which demonstrates that 

thiram may not serve as an effective avian repellant. The study results showed that when wheat 

seeds treated with 600 ppm of thiram were broadcasted on the ground at initial densities of 100 

seeds/m2

, 49 to 32% of the seeds were consumed within three days and were completely 

devoured them within seven days.

Thiram and ferbam are both practically non-toxic to honey bees on an acute contact exposure 

basis. No other toxicity data are available for terrestrial invertebrates. No terrestrial plant toxicity 

data are available for thiram or ferbam.
Page 20 of 60

Table 10. Summary of Most Sensitive Toxicity Endpoints for Terrestrial Organisms Exposed to 

Thiram

Taxonomic 

Group Study Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured a.i.

(Acute Toxicity Category

or Most Sensitive 

Endpoints)

MRID and 

Study 

Classification

Birds

Acute Oral

TGAI

(99.0%)

Ring-neck Pheasant 

(Phasianus 

colchicus)

LD50 = 673 mg/kg-bw

(Slightly toxic)

00160000

Supplemental

TGAI

(% unknown)

Passerine: Red-wing 

Blackbird (Agelaius 

phoeniceus)

LD50 >100 mg/kg-bw

(Moderately toxic)

00073683,

00020560

Supplemental

Sub-acute 

dietary

TGAI

(95.0%)

Bobwhite quail

(Colinus 

virginianus)

LC50 = 3950 mg/kg-diet

(Slightly toxic)

00022293

Acceptable

Chronic TGAI

(98.7%)

Mallard duck (Anas 

platyrhynchos)

NOAEC = 9.6 mg/kg-diet

LOAEC = 39.7 mg/kg-diet

(Eggs set, viable embryos, 

live 3-week embryos, normal 

hatchlings, 14-d survivors, 

eggs set/eggs laid, normal 

hatchlings/live 3-week 

embryos, normal 

hatchlings/eggs laid)

45441201

Acceptable

Mammals1

Acute Oral TGAI

(99.0%)

Laboratory rat

(Rattus norvegicus)

LD50 = 1800 mg/kg-bw

(Slightly toxic)

00153548

Acceptable

Acute 

Inhalation

TGAI

(% unknown) 2.60 < LC50 < 5.04 mg/L 40216501

Acceptable

Chronic (2-

generation 

reproduction)

TGAI

(100%)

NOAEC = 1.4 mg/kgbw/day

LOAEC = 4.2 mg/kgbw/day

(F0 & F1 body weight)

45441203

Acceptable

Terrestrial 

Invertebrates

Acute 

contact

TGAI

(% unknown)

Honey bee

(Apis mellifera)

48-hr LD50 = 73.72 μg/bee

(Practically non-toxic)

00036935

Acceptable

Terrestrial 

Plants

Seedling 

Emergence No data available

Vegetative 

Vigor No data available

1 Mammalian toxicity endpoints provided and reviewed by the U.S. EPA Office of Pesticide Programs Health Effects 

Division (HED).

Table 11. Summary of Most Sensitive Toxicity Endpoints for Terrestrial Organisms Exposed to 

Ferbam

Taxonomic 

Group Study Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured a.i.

(Acute Toxicity Category

or Most Sensitive 

Endpoints)

MRID and 

Study 

Classification

Birds Acute Oral No data available
Page 21 of 60

Taxonomic 

Group Study Type

Test 

Substance

(% a.i.)

Surrogate Species

Toxicity Value

measured a.i.

(Acute Toxicity Category

or Most Sensitive 

Endpoints)

MRID and 

Study 

Classification

Sub-acute 

dietary

TGAI

(% unknown)

Bobwhite quail

(Colinus 

virginianus)

LC50 = 2940 mg/kg-diet

(Slightly toxic)

00106146

Supplemental

Chronic No data available

Mammals1

Acute Oral TGAI

(91.8%) Laboratory rat

(Rattus norvegicus)

LD50 >5,000 mg/kg-bw

(Practically non-toxic)

40561501

Acceptable

Acute 

Inhalation

TGAI

(91.8%)

LC50 = 0.40 mg/L

(Toxicity Category II –

Moderately toxic)

41508101

Acceptable

Chronic No data available

Terrestrial 

Invertebrates

Acute 

contact

Fermate 

Formulation

Honey bee

(Apis mellifera)

48-hr LD50 >12.09 μg/bee

(Practically non-toxic)

00036935

Acceptable

Terrestrial 

Plants

Seedling 

Emergence No data available

Vegetative 

Vigor No data available

1 Mammalian toxicity endpoints provided and reviewed by the U.S. EPA Office of Pesticide Programs Health Effects 

Division (HED).

6.3. Ecological Incidents

The ecological incident information system (EIIS) is an OPP database that houses ecological 

incidents that have been reported to the Agency. When available, EIIS includes date and location 

of an incident, type and magnitude of effects observed in various species, use(s) of pesticides 

known or suspected of contributing to the incident, and results of any chemical residue analysis 

or other analyses conducted during incident investigation. EIIS incidents are categorized 

according to the certainty that the incident resulted from pesticide exposure. The Avian 

Monitoring System (AIMS) is a database administered by the American Bird Conservancy that 

contains publicly available data on reported avian incidents involving pesticides. Many of the 

incidents listed in this database are also in the EIIS. Additionally, the U.S. EPA Office of 

Pesticide Programs Incident Data System (IDS) compiles aggregate incidents reported to the 

agency. These reports do not include detailed information about the incidents. An absence of 

reports does not necessarily equate to an absence of incidents given the nature of incident 

reporting.

EIIS returned one fish incident and one bird incident for thiram. The fish incident, I025285-001, 

occurred in Indiana in 1999, when 4.6 million fish over 50 miles were killed as a result of an 

intentional misuse involving discharge into a river. This incident was attributed to thiram 

exposure with “highly probable” certainty. The bird incident, I005754-012, occurred in 

California in 1972 when 200 cedar waxwings were found dead in a residential area. No 

detectable residues were found in tissue samples or on food sources and the incident was 

considered unlikely to have been caused by thiram exposure. The birds were feeding on 

pyracantha berries, which can intoxicate birds when they are fermented. This incident was also 
Page 22 of 60

reported in AIMS. No incidents were reported for ferbam in EIIS or AIMS. Based on 

information in IDS, no aggregate incidents were reported by registrants for thiram or ferbam.

7. Exposure Pathways of Concern

The environmental fate properties and use patterns of thiram and ferbam indicate that direct 

spray, spray drift, and runoff represent potential transport mechanisms to aquatic and terrestrial 

organisms. Thiram residues appear to have low mobility in the environment and would not be 

expected to leach. Consumption of treated seeds by birds and mammals and consumption of 

seedlings from seeds treated with thiram may also pose a risk of concern (USEPA, 2004a). The 

repellent nature of thiram at dietary concentrations sufficient to cause acute lethality may 

mitigate the concern for acute risk to birds and mammals. However, this is not the case for 

concentrations of concern for chronic risk (see discussion in Section 6).

Drinking water and inhalation exposure pathways were screened using the SIP (Screening 

Imbibition Program) and STIR (Screening Tool for Inhalation Risk) screening methods with 

thiram data. SIP results indicated that drinking water alone is a potential chronic exposure 

pathway of concern for birds and mammals (see Appendix A). STIR results showed that droplet 

inhalation may be an exposure pathway of concern for birds, but exposure via vapor inhalation is 

not likely to be significant (see Appendix B). This is based on the highest ground application 

rate for golf course turf (16.3 lbs a.i./A); however, droplet exposure from this use is expected to 

be limited as birds are likely to leave the field during a ground application. If the highest aerial 

application rate is modeled (strawberry, 3.3 lbs a.i./A), STIR results show no risk concerns for 

birds or mammals. The STIR output is based on a lower bound rat inhalation toxicity endpoint 

(2.60 < LC50 < 5.04 mg/L) and therefore may overestimate the potential for risk. SIP and STIR 

are described in detail at: http://www.epa.gov/oppefed1/models/terrestrial/index.htm.

8. Analysis Plan

8.1. Stressors of Concern

For both ferbam and thiram, thiram is the stressor of concern for both the ecological and drinking 

water risk assessments for registration review. The major degradates of thiram, COS, CS2, and 

CO2, are volatile compounds and are not expected to persist in water or soil. CS2 may cause 

respiratory distress to wildlife in the immediate area if it is if inhaled.4 This exposure pathway 

for CS2 will be considered in the risk assessment.

8.2. Measures of Exposure 

EFED will use standard available models to evaluate potential exposures to aquatic and 

terrestrial organisms as described at http://www.epa.gov/oppefed1/models/water/index.htm and 

 4 See http://www.epa.gov/ttnatw01/hlthef/carbondi.html#ref1 and 

http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=474&tid=84 for additional information on carbon disulfide.
Page 23 of 60

http://www.epa.gov/pesticides/science/models_db.htm. The Surface Water Concentration 

Calculator (SWCC) is currently the model typically used to estimate aquatic exposure. T-REX 

and TerrPlant are currently models typically used to estimate terrestrial exposure. Thiram’s use 

as a wildlife repellent will be considered when characterizing potential exposure to terrestrial 

animals.

Exposure to ferbam (X) will be calculated in thiram equivalents (Y) using the molecular weight 

conversion detailed in the following equation. This equation assumes that for every two ferbam 

molecules, three thiram molecules are formed. This is consistent with the approach used in the 

ferbam RED (USEPA, 2004b).

Y lb thiram/A = X lb ferbam/A * [(240.43 g/mole thiram * 3) / (416.49 g/mole ferbam * 2)]

This equation simplifies to:

Y lb thiram/A = X lb ferbam/A * 0.865

At this time, there are limited monitoring data available for thiram in either ground or surface 

water, with no reported detections. The Pesticides in Ground Water Database (1991) contains no 

records for thiram; STORET contains no detections of thiram. No detections of thiram have been 

reported to the Agency under 6(a)2. The US Geological Survey National Water Quality 

Assessment program (NAWQA) is not currently analyzing for thiram in their samples, and they 

do not have analytical methods in place for this chemical.

8.3. Measures of Effect 

Toxicity data presented in Section 6 of this problem formulation will be used to calculate risk 

quotients. Thiram toxicity data will be used to evaluate both ferbam and thiram uses. Where data 

are available for ferbam and the endpoints are lower (more toxic) than the equivalent study with 

thiram, the ferbam data will be used to evaluate ferbam uses. Any additional information 

submitted by the registrant or found in the open literature prior to conduct of the risk assessment 

will also be considered. The open literature studies are identified using EPA’s ECOTOXicology 

database (ECOTOX) (USEPA, 2007), which employs a literature search engine for locating 

chemical toxicity data for aquatic life, terrestrial plants, and wildlife. The evaluation of both 

sources of data can also provide insight into the direct and indirect effects of pesticides on biotic 

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

structure and functional characteristics of the affected communities.

8.4. Endangered Species Assessments

Consistent with EPA’s responsibility under the Endangered Species Act (ESA), the Agency will 

evaluate risks to federally listed threatened and endangered (listed) species from registered uses 

of pesticides in accordance with the Joint Interim Approaches developed to implement the 

recommendations of the April 2013 National Academy of Sciences (NAS) report, Assessing 

Risks to Endangered and Threatened Species from Pesticides. The NAS report outlines 

recommendations on specific scientific and technical issues related to the development of 
Page 24 of 60

pesticide risk assessments that EPA and the Services must conduct in connection with their 

obligations under the ESA and FIFRA. EPA will address concerns specific to thiram and ferbam

in connection with the development of its final registration review decision for thiram and 

ferbam.

In November 2013, EPA, the U.S. Fish and Wildlife Service, National Marine Fisheries (the 

Services), and USDA released a white paper containing a summary of their joint Interim 

Approaches for assessing risks to listed species from pesticides. These Interim Approaches were 

developed jointly by the agencies in response to the NAS recommendations, and reflect a 

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

differences between the EPA and the Services. Details of the joint Interim Approaches are 

contained in the November 1, 2013 white paper, Interim Approaches for National-Level 

Pesticide Endangered Species Act Assessments Based on the Recommendations of the National 

Academy of Sciences April 2013 Report.

Given that the agencies are continuing to develop and work toward implementation of the 

Interim Approaches to assess the potential risks of pesticides to listed species and their 

designated critical habitat, this ecological problem formulation supporting the Preliminary Work 

Plan for thiram and ferbam does not describe the specific ESA analysis, including effects 

determinations for specific listed species or designated critical habitat, to be conducted during

registration review. While the agencies continue to develop a common method for ESA analysis, 

the planned risk assessment for the registration review of thiram and ferbam will describe the 

level of ESA analysis completed for this particular registration review case. This assessment will 

allow EPA to focus its future evaluations on the types of species where the potential for effects 

exists, once the scientific methods being developed by the agencies have been fully vetted. Once 

the agencies have fully developed and implemented the scientific methods necessary to complete 

risk assessments for listed species and their designated critical habitats, these methods will be 

applied to subsequent analyses of thiram and ferbam as part of completing this registration

review.

8.5. Endocrine Disruptor Screening Program

Thiram and ferbam were not included in the first group of 67 chemicals issued an order to 

conduct Tier 1 EDSP testing. Thiram and ferbam are not on the second list of chemicals for Tier 

1 screening. For additional information the EDSP program, visit http://www.epa.gov/endo/.

9. Preliminary Identification of Data Gaps 

9.1. Environmental Fate

Tables 12 and 13 identify environmental fate studies by MRID for ferbam and thiram, 

respectively, that offer data for each guideline requirement, as well as study classifications and 

whether or not further data are needed in order to support risk assessment.
Page 25 of 60

Acceptable guideline studies on hydrolysis and adsorption/desorption have not been submitted

for thiram. However, the supplemental data listed in the tables below can be used in conjunction 

with the acceptable guideline study data to quantitatively assess the environmental fate of the 

chemical.

Independently validated environmental chemistry methods (ECM/ILV) for measuring thiram in 

soil and water are available. While separate methods are not available for ferbam, the thiram 

methods are fully adequate to assess residues from a ferbam treated field. 

Table 12. Submitted Environmental Fate Data for Ferbam

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

835.2120 Hydrolysis 45714101

41840601

Supplemental

Supplemental No

835.2240 Photodegradation in 

Water

45651201

41758301

Acceptable

Supplemental No

835.2410 Photodegradation on 

Soil

45724501

43661801

Acceptable

Invalid No

835.4100 Aerobic Soil 

Metabolism 43734901 Acceptable No

835.4200 Anaerobic Soil 

Metabolism 40768103 Invalid No

835.4300 Aerobic Aquatic 

Metabolism 45243401 Acceptable No

835.4400 Anaerobic Aquatic 

Metabolism 43628501 Acceptable No

835.1230

835.1240

LeachingAdsorption/Desorption 43787501 Supplemental No

835.6100 Terrestrial Field 

Dissipation

44724501

44724502

Supplemental

Acceptable No

Table 13. Submitted Environmental Fate Data for Thiram

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

835.2120 Hydrolysis 45714101

41840601

Supplemental

Supplemental No

835.2240 Photodegradation in 

Water

45651201

41758301

Acceptable

Supplemental No
Page 26 of 60

835.2410 Photodegradation on 

Soil

45724501

43661801

Acceptable

Invalid No

835.4100 Aerobic Soil 

Metabolism 43734901 Acceptable No

835.4200 Anaerobic Soil 

Metabolism 40768103 Invalid No

835.4300 Aerobic Aquatic 

Metabolism 45243401 Acceptable No

835.4400 Anaerobic Aquatic 

Metabolism 43628501 Acceptable No

835.1230

835.1240

Leaching-Adsorption/

Desorption

43787501 Supplemental No

835.6100 Terrestrial Field 

Dissipation

44724501

44724502

Supplemental

Acceptable No

9.2. Effects

Tables 14 and 15 identify aquatic and terrestrial ecological effects studies, respectively, by 

MRID that offer data for each guideline requirement, as well as study classifications and whether 

or not further data are needed in order to support risk assessment. These tables are presented only 

for thiram because thiram toxicity data is considered sufficient for the assessment of both ferbam 

and thiram uses. No additional toxicity data on ferbam are requested. Rationale for the additional 

non-guideline data requested is presented below the tables.

Table 14. Submitted Aquatic Ecological Effects Data for Thiram

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

850.1010

Freshwater 

invertebrate

acute toxicity

00164662 Acceptable No None

850.1025

850.1035

850.1045

850.1055

Saltwater 

invertebrate

acute toxicity

42488301 Acceptable

No None

42488302 Acceptable

850.1075 Freshwater fish acute 

toxicity

TN 996 Acceptable

No None

TN 1001 Acceptable

00002923/

00021610 Supplemental

00090293 Supplemental

00090294 Supplemental

05020144 Supplemental
Page 27 of 60

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

46249301 Supplemental

850.1075 Saltwater fish acute 

toxicity 42514401 Acceptable No None

850.1300

Freshwater 

invertebrate

life cycle

47495001 Acceptable No None

850.1350

Saltwater 

invertebrates

life cycle

None NA Yes

Data are needed to reduce 

uncertainty in the 

assessment of chronic risk 

to estuarine/marine 

invertebrates. A chronic 

mysid study conducted 

with ferbam (MRID 

47784401) did not 

establish a NOAEC. A 

new study with thiram is 

recommended.

850.1400 Freshwater fish

early-life stage

46249303 Supplemental

No None

47495002

Not reviewed

(preliminary 

report for 

850.1500)

850.1400 Saltwater fish

early-life stage None NA Yes

Data are needed to reduce 

uncertainty in the 

assessment of chronic risk 

to estuarine/marine fish.

850.1500 Fish life cycle 47824101 Acceptable No None

850.1735

Whole sediment 10-d 

freshwater 

invertebrate

None NA No

None. Thiram is not 

expected to accumulate in 

sediment.

850.1740

Whole sediment 10-d 

estuarine/marine 

invertebrate

None NA No

None. Thiram is not 

expected to accumulate in 

sediment.

850.4400

Aquatic plant 

Toxicity Test using 

Lemna spp.

45441202 Acceptable No None

850.4500 Algal toxicity 44086001/ 

44086101 Acceptable Yes

Studies with two additional 

species will reduce 

uncertainty in the 

assessment of risk to nonvascular plants. Suggested 

species are the freshwater 

diatom Navicula 

pelliculosa and the marine 

diatom Skeletonema 

costatum.
Page 28 of 60

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

850.4550 Cyanobacteria None NA Yes

A cyanobacteria will 

reduce uncertainty in the 

assessment of risk to nonvascular plants.

Table 15. Submitted Terrestrial Ecological Effects Data for Thiram

OCSPP 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

850.2100 Avian oral toxicity

00160000 Acceptable

Yes

An acceptable study with a 

passerine species will 

reduce uncertainty in the 

assessment of risk to birds.

00073683/ 

00020560 Supplemental

850.2200 Avian dietary 

toxicity 00022293 Acceptable No None

850.2300 Avian reproduction

43612501 Supplemental

43612502 Acceptable No None

45441201 Acceptable

Nonguideline Avian inhalation None NA No

While STIR indicated a 

potential risk to birds from 

droplet inhalation, this was 

only for ground 

applications and the 

inhalation toxicity endpoint 

used was a lower bound 

estimate. Risk concerns 

from this exposure 

pathway are expected to be 

minor compared to dietary 

exposure and a study is not 

requested at this time.

850.3020 Honey bee acute 

contact toxicity 00036935 Acceptable No None

850.3030 Honey bee residue 

on foliage None NA No

None. Acute contact 

toxicity endpoint is >11 

μg/bee.

850.3040 Field testing for 

pollinators (Tier III) None NA Yes

See justification tables 

below for additional 

details.

Nonguideline

(Tier I)

Honey bee adult 

acute oral toxicity None NA Yes

An adult acute oral study 

will reduce uncertainty in 

the risk assessment for 

pollinators. See 

justification tables below 

for additional details.
Page 29 of 60

OCSPP 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

Nonguideline

(Tier I)

Honey bee larvae

acute toxicity None NA Yes

A larvae acute study will 

reduce uncertainty in the 

risk assessment for 

pollinators. See 

justification tables below 

for additional details.

Nonguideline

(Tier I)

Honey bee adult 

chronic 10d toxicity None NA Yes

An adult chronic oral study 

will reduce uncertainty in 

the risk assessment for 

pollinators. See 

justification tables below 

for additional details.

Nonguideline

(Tier I)

Honey bee larvae

chronic toxicity None NA Yes

A larvae chronic study will 

reduce uncertainty in the 

risk assessment for 

pollinators. See 

justification tables below 

for additional details.

Nonguideline

(Tier II)

Semi-field testing 

for pollinators 

(tunnel or colony 

feeding studies)

None NA Yes

See justification tables 

below for additional 

details.

Nonguideline

(Tier II)

Field trial of 

residues in pollen 

and nectar

None NA Yes

See justification tables 

below for additional 

details.

850.4100 Seedling 

Emergence None NA Yes

A seedling emergence 

study will reduce 

uncertainty in the 

assessment of risk to 

terrestrial plants. 

850.4150 Vegetative Vigor None NA Yes

A vegetative vigor study 

will reduce uncertainty in 

the assessment of risk to 

terrestrial plants.

Study Title: Pollinator Acute Oral Toxicity, Adult

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. 

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to the hive. Therefore, potential acute effects to adult honeybees and other pollinators from oral 

exposure to some pesticides could exist. Currently available toxicity studies do not address possible 

effects of oral exposure on adult terrestrial insect survival. Because of the potential for pollen and 

nectar to be contaminated with pesticide residues, and subsequently brought back to the hive, it is 

important to determine the acute oral toxicity of this compound to adult honeybees and other insect 

pollinators.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 
Page 30 of 60

terrestrial invertebrates using the honeybee as a surrogate test species. The guidance discusses Tier I 

laboratory-based acute oral toxicity studies of individual adult bees as a critical component of the 

screening-level risk assessment process for examining potential adverse effects from specific routes of 

exposure. The guidance can be found at: http://www2.epa.gov/pollinator-protection/pollinator-riskassessment-guidance. Additional guidance on the honeybee oral toxicity test design can be found in 

OECD Test Guideline 213 http://www.oecd-ilibrary.org/environment/test-no-213-honeybees-acuteoral-toxicity-test_9789264070165-en.

Practical Utility of the Data

How will the data be used?

The Tier I acute oral toxicity data on adult bees serve as a foundation for the screening-level 

assessment of potential risk to non-target organisms such as federally listed threatened or endangered 

and non-listed terrestrial invertebrate insects, including pollinators, from acute oral exposures to 

pesticides. The data will be used to reduce uncertainties associated with the risk assessment for 

terrestrial invertebrates and will improve EPA’s understanding of the potential direct and indirect 

effects on a broad range of taxa. This study will also provide information with which to compare 

whether oral toxicity estimates differ from contact toxicity estimates obtained from other Tier I studies. 

If acute oral effects data for adult honeybees and insect pollinators are not available, risks to terrestrial 

insects from acute oral exposure will be assumed.

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

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is 

likely to adversely affect listed threatened or endangered species and/or modify their designated critical 

habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide 

products to comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Pollinator Acute Oral Toxicity, Larvae

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. 

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to the hive where larvae and pupae may be exposed. Therefore, potential adverse effects to 

developing bees and other insect pollinators could result from exposure to pesticide residues. Available 

toxicity studies do not address possible effects on brood (larvae and pupae) survival/development. 

Because of the potential for pollen and nectar to be contaminated with pesticide residues, and 

subsequently brought back to the hive, it is important to determine the acute oral toxicity of this 

compound to bee brood. 

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

terrestrial invertebrates using the honeybee as a surrogate test species. The guidance discusses Tier I 

laboratory-based acute toxicity studies of individual honeybee larvae as a critical component of the 

screening-level risk assessment process for examining potential risks from specific routes of exposure. 

The guidance can be found at: http://www2.epa.gov/pollinator-protection/pollinator-risk-assessmentguidance. Additional guidance on larval honeybee toxicity test design can be found in OECD Test 

Guideline 237 http://www.oecd-ilibrary.org/environment/test-no-237-honey-bee-apis-mellifera-larvaltoxicity-test-single-exposure_9789264203723-en.

Practical Utility of the Data

How will the data be used?

The Tier I acute oral toxicity data on honeybee larvae serve as a foundation for the screening-level 
Page 31 of 60

assessment of potential risk to non-target organisms such as federally listed threatened or endangered 

and non-listed terrestrial invertebrate insects, including pollinators, and/or modify their designated 

critical habitat from acute oral exposures to pesticides. The data will be used to reduce uncertainties 

associated with the risk assessment for terrestrial invertebrates and will improve EPA’s understanding 

of the potential effects on terrestrial species and whether there is a differential sensitivity of larval bees 

relative to adult bees. If acute oral effects data for larvae are not available, risks to terrestrial insects 

from acute oral exposure will be assumed.

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

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is 

likely to adversely affect listed threatened or endangered species and/or modify their designated critical 

habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide 

products to comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Pollinator Chronic Oral Toxicity, Adult

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. 

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to the hive. Therefore, potential chronic effects to adult honeybees and other pollinators from oral 

exposure to some pesticides could exist. Currently available toxicity studies do not address possible 

lethal and sublethal effects of chronic oral exposure on adult terrestrial invertebrates and will assist in 

determining whether the sensitivity of adult bees differs from that of earlier life stages. Because of the 

potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought 

back to the hive, it is important to determine the chronic oral toxicity of this compound to adult 

honeybees and other pollinators.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance discusses Tier I laboratory-based chronic oral toxicity 

studies of individual adult honeybees as a critical component of the screening-level risk assessment 

process for examining potential risks from specific routes of exposure. The guidance can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance. Study design elements 

for the chronic 10-day oral toxicity test with honeybees are similar to the OECD Test Guideline 213 

acute oral toxicity test http://www.oecd-ilibrary.org/environment/test-no-213-honeybees-acute-oraltoxicity-test_9789264070165-en.

Practical Utility of the Data

How will the data be used?

The Tier I chronic oral toxicity data on adult bees serve as a foundation for the screening-level 

assessment of potential risk to non-target organisms including federally listed threatened or endangered 

species and non-listed terrestrial invertebrate insects, including pollinators, from chronic oral exposures 

to pesticides. The data will be used to reduce uncertainties associated with the risk assessment for 

terrestrial invertebrates and will improve EPA’s understanding of the potential direct and indirect lethal 

and sublethal effects on a broad range of terrestrial species, particularly insect pollinators and to 

determine whether adult toxicity differs substantially from other life stages evaluated in other Tier I 

tests. If chronic oral effects data for adults are not available, risks to terrestrial insects from chronic oral 

exposure will be assumed.

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

The data will inform the determination required under FIFRA or the ESA as to whether continued 
Page 32 of 60

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is 

likely to adversely affect listed threatened or endangered species and/or their designated critical habitat. 

Without these data, EPA may need to presume risk which will limit the flexibility of pesticide products 

to comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Pollinator Chronic Oral Toxicity, Larvae

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticides in various use settings. 

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to the hive where larvae and pupae may be exposed. Therefore, potential effects to developing 

bees could result from chronic oral exposure to pesticide residues. Available toxicity studies do not 

address possible chronic effects on brood (larvae and pupae) survival. Because of the potential for 

pollen and nectar to be contaminated with pesticide residues, and subsequently brought back to the 

hive, it is important to determine chronic larval/pupal toxicity and whether adult emergence is 

adversely affected. This study will provide information on whether honeybee larvae differ in sensitivity 

from adult bees following chronic exposure. 

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance discusses Tier 1 laboratory-based chronic oral toxicity 

studies of individual honeybee larvae as a critical component of the screening-level risk assessment 

process for examining potential risks from specific routes of exposure. The guidance can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance.

Additional information on larval honeybee toxicity repeat exposure test design can be found in the 

OECD draft guidance 

http://www.oecd.org/env/ehs/testing/Draft_GD_honeybees_rep_exp_for_2nd_CR_25_November_201

3.pdf.

Practical Utility of the Data

How will the data be used?

The Tier I chronic oral toxicity data on bee larvae serve as a foundation for the screening-level 

assessment of potential risk to non-target organisms including federally listed threatened or endangered 

and non-listed terrestrial invertebrate insects, including pollinators, from chronic oral exposures to 

pesticides. The data will be used to reduce uncertainties associated with the risk assessment for 

terrestrial invertebrates and will improve EPA’s understanding of the potential direct and indirect lethal 

and sublethal effects on a broad range of terrestrial species, particularly insect pollinators. These data 

will also assist in determining whether early life stages of the bee differ in their sensitivity to pesticides 

relative to adults. If chronic oral effects data for larvae are not available, risks to terrestrial insects from 

chronic oral exposure will be assumed.

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

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is 

likely to adversely affect listed threatened or endangered species and/or modify their designated critical 

habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide 

products to comply with FIFRA and the ESA, and could result in use restrictions. 

Study Title: Pollinator Tier II Semi-Field Toxicity Testing (tunnel/enclosure studies)

Rationale for Requiring the Data

Tier II studies are conditional on the outcome of the screening-level assessment where acute and/or 
Page 33 of 60

chronic risk levels of concern have been exceeded for terrestrial invertebrates. Terrestrial invertebrates 

are likely to be impacted if exposed to pesticides in various use settings. Pesticide residues may be 

transferred to pollen and/or nectar of treated plants and subsequently brought back to the hive and may 

adversely affect developing brood (egg, larvae, and pupae) and adult bees. Screening-level (Tier I) 

studies of individual bees do not address possible effects and/or exposure to pesticide residues at the 

colony-level. Because of the potential for pollen and nectar to be contaminated with pesticide residues, 

and subsequently brought back to the hive, it is important to determine whether bee colonies may be 

negatively affected under relatively controlled exposure conditions of a semi-field study. In addition to 

providing effects data, these studies can provide data on exposure as pesticide residues in pollen/nectar 

of treated plants.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance describes the tiered testing process and can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance. Additional information 

on honeybee colony studies under semi-field conditions can be found in the OECD Guidance 75 

http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env/jm/mono%28. 

Practical Utility of the Data

How will the data be used? 

Tier II colony-level data will be used to assess potential risk to non-target organisms including listed 

and non-listed terrestrial social invertebrate species and to determine whether effects observed in the 

screening-level (Tier I) laboratory-based studies of individual bees are evident in colony-level studies 

under semi-field conditions. The Tier II semi-field test of whole colonies is a relatively controlled 

study, i.e., bees are confined to a specific area, that is designed to represent potential field-level 

exposure and account for hive dynamics, which are not achievable from other pollinator studies. This 

study will be used to determine whether adverse effects to insect pollinators at the whole colony level, 

may result for the use of pesticides and will help to refine risk estimates derived in the screening-level 

risk assessment for beneficial terrestrial invertebrates. Measured residues in pollen/nectar can also be 

used to refine risk estimates derived from model-based or default values in the screening-level 

assessment.

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

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is 

likely to adversely affect federally listed threatened or endangered species or their designated critical 

habitat. Without these data, EPA may need to presume risk which will limit the flexibility of pesticide 

products to comply with FIFRA and the ESA, and could result in significant use restrictions.

Study Title: Pollinator Tier II Semi-Field Toxicity Testing (feeding studies)

Rationale for Requiring the Data

Pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently brought 

back to the hive, and may adversely affect developing brood (egg, larvae, and pupae) and adult bees. 

Tier II feeding studies are conditional on the outcome of the screening-level assessment where acute 

and/or chronic risk levels of concern have been exceeded for terrestrial invertebrates based on Tier I 

studies of individual bees. Feeding studies utilize free foraging bee colonies that are “dosed” with 

specific quantities of test material and represent a means of ensuring exposure to the test material 

through spiked pollen and/or sugar solutions fed to the colony while still allowing the bees to forage 

freely. Since bee colonies are not confined to enclosures, colonies can be exposed for longer duration 

periods without subjecting the bees to stress that typically results from Tier II tunnel studies. Available 

toxicity studies of individual bees (Tier 1) conducted to support screening-level assessments do not 
Page 34 of 60

address possible effects and/or exposure to pesticide residues at the colony-level. Because of the 

potential for pollen and nectar to be contaminated with pesticide residues, and subsequently brought 

back to the hive, it is important to determine whether bee colonies may be negatively affected where 

bees are free foraging and have the option to collect/consume alternative forage items beyond the 

spiked food. Since multiple dose levels can be more readily tested, feeding studies can help to define 

dose-response relationships at the whole colony level.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance describes the tiered testing process and can be found at: 

http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance. Additional information 

on honeybee colony feeding studies can be found in the EPPO Guidance 170 at: 

http://www.nationalbeeunit.com/index.cfm?pageId=187.

Practical Utility of the Data

How will the data be used?

Tier II colony feeding data will be used to assess potential risk to non-target organisms including listed 

and non-listed terrestrial social invertebrate species. The colony feeding study is designed to represent 

potential field-level exposure and account for hive dynamics using longer duration exposure periods 

than are possible in Tier II tunnel studies. The study will be used to determine whether potential 

adverse effects to insect pollinators at the whole colony level when bees are able to forage naturally 

beyond the spiked food. Results from the feeding study will help to refine the screening-level risk 

assessment for beneficial terrestrial invertebrates that were based on Tier I studies on individual bees. 

Since feeding studies can help to define a dose-response relationship at the colony level, the studies can 

provide a means of determining exposure thresholds below which the likelihood of adverse effects on 

colonies may be low.

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

Tier II colony-level data will be used to refine screening-level risk estimates derived using Tier I 

laboratory-based data on individual bees. The Tier II data will inform the determination required under 

FIFRA or the ESA as to whether continued registration of a pesticide is likely to result in unreasonable 

adverse effects to non-target species or is likely to adversely affect federally listed threatened or 

endangered species or their designated critical habitat. Without these data, EPA may need to presume 

risk which will limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could 

result in significant use restrictions.

Study Title: Residues in Pollen and Nectar

Rationale for Requiring the Data

Terrestrial invertebrates are likely to be impacted if exposed to pesticide residues in various use 

settings. Pesticide residues may be transferred to pollen and/or nectar of treated plants and 

subsequently brought back to hive where all life stages may be exposed. For some pesticides, the 

quantification of pollinator-relevant residues in treated flowering plants is needed, since pollinators will 

be exposed to residues from either current or prior season applications (due to the potential for residues 

to accumulate in plants and trees). Residues in edible/transportable-to-hive parts of treated trees and 

plants, including (where appropriate), but not limited to, guttation water, sap/resins, whole plant tissue 

(e.g., leaves, stems), as well as blooming, pollen-shedding, and nectar producing parts (i.e., flowers 

and, if present, extra-floral nectaries) of plants may inform the potential for risk. Studies should be 

designed to provide residue data for crops and application methods of concern.

The Office of Pesticide Programs has made available a guidance regarding ecological testing for 

invertebrates with the honeybee. The guidance can be found at: http://www2.epa.gov/pollinator-
Page 35 of 60

protection/pollinator-risk-assessment-guidance.

Practical Utility of the Data

How will the data be used?

Measured residue data will be used to refine conservative estimates of pesticide exposure and reduce 

uncertainties associated with the Tier I exposure assessment by providing direct measurements of 

pesticide concentrations resulting from actual use settings. Measured residues may provide a more 

realistic understanding of exposure through contact or ingestion with which to calculate risk quotients 

for individual bees as well as to characterize exposure to the colony. If measured residue data are not 

available, risk estimates for terrestrial insects will be based on model-generated or default values used 

to support the screening-level assessment.

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

The data will inform the determination required under FIFRA or the ESA as to whether continued 

registration of a pesticide is likely to result in unreasonable adverse effects to non-target species or is 

likely to adversely affect federally listed threatened or endangered species or their designated critical 

habitat. Without these data, EPA will have to rely on conservative estimates of exposure which will 

limit the flexibility of pesticide products to comply with FIFRA and the ESA, and could result in use 

restrictions. 

10. References

Dhinsa, Manjit S, P.S. Sandhu, Harjeet K. Saini, and H.S. Toor. 1991. House crow damage to 

sprouting sunflower. Department of Zoology, Punjab Agricultural University, Ludhiana, 

Punjab- 141,004, India

Madsen, J. 1996. Exposure of spring-staging pink-footed geese Anser brachyrhynchus to

pesticide-treated seed. Wildlife Biology 2:1-9.

United States Environmental Protection Agency (USEPA). 2004a. Carleton, J., F. Jenkins, and 

W. Eckel. Environmental Fate and Ecological Risk Assessment for the Reregistration of 

Thiram. U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and 

Toxic Substances, Environmental Fate and Effects Division. Sept. 30, 2004.

USEPA. 2004b. Federoff, N.E. and J. Melendez. EFED RED Chapter for Ferbam. DP Barcode 

281025. U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and 

Toxic Substances, Environmental Fate and Effects Division. Memorandum to the Special 

Review and Reregistration Division. Dec. 22, 2004.

USEPA. 2004c. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. U.S. Environmental Protection Agency, Office of Pesticide Programs, 

Environmental Fate and Effects Division. Available at 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf

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/
Page 36 of 60

USEPA. 2014a. Screening Level Usage Analysis (SLUA) for Ferbam (034801). U.S. 

Environmental Protection Agency, Office of Pesticide Programs, Biological and 

Economic Analysis Division. June 11, 2014.

USEPA. 2014b. Screening Level Usage Analysis (SLUA) for Thiram (079801). U.S. 

Environmental Protection Agency, Office of Pesticide Programs, Biological and 

Economic Analysis Division. Nov. 4, 2014.

USEPA. 2015. Arnold, E. and R. Parker. Registration Review: Preliminary Problem Formulation 

for Environmental Fate, Ecological Risk, Endangered Species, and Human Health 

Drinking Water Exposure Assessments for Ziram. DP Barcode 427965. U.S.

Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, 

Environmental Fate and Effects Division. Memorandum to the Pesticide Re-evaluation 

Division.

USEPA, PMRA, and CDPR. 2014. Guidance for Assessing Pesticide Risks to Bees. Office of 

Pesticide Programs, USEPA, Washington D.C. Health Canada Pest Management 

Regulatory Agency, Ottawa, ON, Canada. California Department of Pesticide Regulation, 

Sacramento, CA. June 23, 2014.

10.1. Submitted Environmental Fate Studies

034801 Ferbam Fate Chemistry Bibliography Revised 21 May 2014

161-1 Hydrolysis

MRID Citation Reference

40088201 2002199

2002008

Warren, J. (1987) Determination of the Hydrolysis Rate of [Carbon 14]-Ferbam: ABC Preliminary 

Report #34375. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 248 p. 

44071801 2015163 Nixon, W.; Atkins, R. (1996) Hydrolysis of (carbon-14) Ferbam in Aqueous Buffered Solutions of 

pH 5, 7 and 9: Lab Project Number: 990: 1898: 95044. Unpublished study prepared by PTRL East, 

Inc. 150 p. 

161-2 Photodegradation-water

MRID Citation Reference

40088202 2002200

2002208

Warren, J. (1986) Determination of the Photolysis Rate of [Carbon 14]-Ferbam: ABC Preliminary 

Report #34373. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 230 p. 

43999801 2015164 Nixon, W. (1996) Aqueous Photolysis of (Carbon 14) Ferbam in Artificial Light: Lab Project 

Number: 1002: 1884. Unpublished study prepared by PTRL East, Inc. 123 p. 

161-3 Photodegradation-soil

MRID Citation Reference

40088203 2002201

2002208

Carpenter, M. (1987) Determination of the Photodegradation Rate of [Carbon 14]-Ferbam: ABC 

Laboratory Project ID: #34374. Unpublished study prepared by Analytical Bio-Chemistry 

Laboratories, Inc. 192 p. 
Page 37 of 60

43999802 2015165 Nixon, W. (1996) Soil Surface Photolysis of (Carbon 14) Ferbam in Artificial Light: Lab Project 

Number: 1003: 1883. Unpublished study prepared by PTRL East, Inc. 100 p. 

162-1 Aerobic soil metabolism

MRID Citation Reference

40550601 2002206

2002209

Daly, D. (1987) Aerobic Soil Metabolism of ?carbon 14|-Ferbam: ABC Draft Final: 34369. 

Unpublished study prepared by ABC Laborat- ories, Inc. 37 p. 

44368901 2015166 Nixon, W.; Atkins, R.; Coody, P. (1997) Aerobic Soil Metabolism of (carbon 14)Ferbam: (Final 

Report): Lab Project Number: 1004: 1903: 95047. Unpublished study prepared by PTRL East, Inc. 

110 p. 

162-2 Anaerobic soil metabolism

MRID Citation Reference

40365301 2002202

2002208

Daly, D. (1987) Anaerobic Soil Metabolism of [Carbon 14]-Ferbam: ABC Preliminary Report #34370. 

Unpublished study prepared by ABC Laboratories, Inc. 226 p. 

44565305 2015167 Coody, P.; Atkins, R. (1998) Anaerobic Metabolism of (carbon 14)Ferbam: Lab Project Number: 

1005: 1969. Unpublished study prepared by PTRL East, Inc. 152 p. 

162-3 Anaerobic aquatic metabolism

MRID Citation Reference

44565305 2015167 Coody, P.; Atkins, R. (1998) Anaerobic Metabolism of (carbon 14)Ferbam: Lab Project Number: 

1005: 1969. Unpublished study prepared by PTRL East, Inc. 152 p. 

163-1 Leach/adsorption/desorption

MRID Citation Reference

98839 Munnecke, D.E. (1961) Movement of nonvolatile, diffusible fungi- cides through columns of soil. 

Phytopathology 51(Sep):593-599. (Also~In~unpublished submission received Jan 4, 1978 under 

239- 1246; submitted by Chevron Chemical Co., Richmond, Calif.; CDL: 232569-S) 

162088 2002222 Drury, P. (1986) Determination of Adsorption/Desorption Constants of [Carbon 14]-Ferbam: ABC 

Preliminary Rept. #34371. Unpub- lished study prepared by Analytical Bio-Chemistry Laboratories, 

Inc. 282 p. 

5001190 Helling, C.S.; Dennison, D.G.; Kaufman, D.D. (1974) Fungicide movement in soils. Phytopathology 

64(8):1091-1100. 

40088204 2015168 Warren, J. (1986) Determination of Adsorption/Desorption Constants of [Carbon 14]-Ferbam: ABC 

Laboratory ID: #34371. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 

306 p. 

164-1 Terrestrial field dissipation

MRID Citation Reference

40550902 2002205

2002209

2015169

Selman, F.; Moezpoor, E. (1988) Ferbam Peach Terrestrial Field Dissipation: Preliminary Report 

No. 35506. Unpublished study prepared by Analytical Bio-chemistry Laboratories, Inc. 65 p. 

40603401 2002204

2002209

Selman, F.; Moezpoor, E. (1988?) Ferbam Apple Terrestrial Field Dissipation: Preliminary Report 

No. 35507. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 138 p. 
Page 38 of 60

Non-Guideline Study

MRID Citation Reference

11559

Richardson, L.T. (19??) The persistence of Thiram in soil and its relationship to the microbiological 

balance and damping-off con- trol. Canadian Journal of Botany 32(? ):335-346. (Also in unpublished submission received Sep 26, 1972 under 1023-15; sub- mitted by Upjohn Co., 

Kalamazoo, Mich.; CDL:024388-B) 

117716. 2002203

2002008

Lemal, R. (1985) Determination of Vapor Pressure of Ferbam: [Iron tris (Dimethyldithiocarbamate)]: 

LPCD No. 162-85. Unpublished study prepared by UCB. 4 p.

98833

Kluge, E. (1969) The Effect of the Soil Reaction on the Degradation and Persistence of Thiuram, 

Ferbam, and Captan in the Soil. A translation of: ?Without Title|. Archiv furer Pflanzenwchutz, 

5(4):263-271. (Unpublished study received Jan 4, 1978 under 239-1246; submitted by Chevron 

Chemical Co., Richmond, Calif.; CDL:232569-J) 

41340903

Vandegans, J. (1987) Determination of the Stability Constant of Iron III-tris (N,NDimethyldithiocarbamate) or Ferbam: Lab Project Nos. F80312; UCB #F80312. Unpublished study 

prepared by C.P.R.S.--C.E.R.I.A. 18 p. 

079801 Thiram Chemical Fate Bibliography Revised 21 July 2014

161-1 Hydrolysis

MRID Citation Reference

148414 2009574 Lemal, R. (1983) Note L.P.C.D. No. 80: TMTD [(Tetramethylthiuram Disulfide)]: Determination of 

Rate of Hydrolysis as a Function of pH. Unpublished translation of Note L.P.C.D. No. 80: DTMT: 

Determination de la Vitesse d'Hydrolyse a Differents pH prepared by UCB. 7 p. Same citation as 

145796

149192 2009616

2075947- draft Lemal, R. (1983) TMTD: Determination of Rate of Hydrolysis as a Function of pH: Aff. 2.24.007: 

Note L.P.C.D. No. 80. Unpublished translation of study prepared by UCB, Drogenbos

Laboratories. 7 p. 

40444703 2009617 

2075948

Cranor, W. (1987) Determination of the Hydrolysis Rate of ?Carbon 14|-Thiram: Laboratory 

Project ID: 34030. Unpublished study prepared by Analytical Bio-Chemistry Laboraotries, Inc. 

675 p. 

41840601 2009626 

2009637- memo

Norris, K. (1991) Determination of the Hydrolysis of ?carbon-14|- Thiram: Lab Project Number: 

91-007: 1156. Unpublished study prepared by Analytical Development Corp. 65 p. 

42245602 2009574

2009637

Norris, K. (1991) Determination of Hydrolysis of ?carbon 14|-Thiram: Addendum No. 1: Lab 

Project Number: 1156. Unpublished study prepared by Analytical Development Corp., (ADC). 7 

p. 

45714101 2011403 

2013242

Shepler, K.; Runes, H. (2002) Hydrolysis of (Carbon 14) Thiram at pH 5, 7, and 9: Lab Project 

Number: 1041W. Unpublished study prepared by PTRL West, Inc. 110 p. 

47337903 See 41840601 Norris, K. (1991) Determination of the Hydrolysis of (Carbon 14)-Thiram. Project Number: 1156, 

9106. Unpublished study prepared by Analytical Development Corp., Inc. 38 p.

161-2 Photodegradation-water

MRID Citation Reference

40444704 2009618 Cranor, W. (1987) Determination of the Photolysis Rate of ?Carbon 14|-Thiram: Laboratory Project 

ID: 33571. Unpublished study prepared by ABC Laboraotries, Inc. 385 p. 

41753801 2009625 

see below

Norris, K.J. 1991. Determination of the Aqueous Photodegradation of 14C-Thiram. Performed by 

Analytical Development Corporation, Colorado Springs, CO. Submitted by Thiram Task Force. 

MRID# 41753801
Page 39 of 60

41758301 2009625 

2009637-

Norris, K. (1990) Determination of the Aqueous Photodegradation of ?Carbon 14|-Thiram: Lab 

Project Number: 1157. Unpublished study prepared by Analytical Development Corp. 58 p. 

42245601 2009574 

2009637 

Norris, K. (1991) Determination of the Aqueous Photodegradation of ?carbon 14|-Thiram: 

Addendum No. 1: Lab Project Number: 1157. Unpublished study prepared by Analytical 

Development Corp., (ADC). 6 p. 

45596101 DER not 

located

Shelper, K.; Runes, H. (2001) Photodegradation of (Carbon-14) Thiram in Sterilized Buffer at pH 5 

by Artificial Light: Lab Project Number: 1042W. Unpublished study prepared by PTRL West, Inc. 116 

p. 

45651201 2004591 

2013242

Shepler, K.; Runes, H. (2002) Photodegradation of (Carbon 14) Thiram in Sterilized Buffer at pH 5 

by Artificial Light: Lab Project Number: 1042W. Unpublished study prepared by PTRL West, Inc. 117 

p. 

161-3 Photodegradation-soil

MRID Citation Reference

40768102 2009620 Carpenter, M.; Fennessey, M. (1987) "Determination of the Photode- gradation Rate of ?Carbon

14|-Thiram on the Surface of Soil": ABC Final Report #33572. Unpublished study prepared by 

Analyti- cal Bio-Chemistry Laboratories, Inc. 600 p. 

43661801 2009628 Burri, R. (1995) Photodegradation Study of (Carbon 14)-Thiram on Soil: Lab Project Number: 

326171. Unpublished study prepared by RCC Umweltchemie AG. 113 p. 

45724501 2011690 Shepler, K.; Runes, H. (2002) Photodegradation of (Carbon 14) Thiram in/on Soil by Artificial Light: 

Lab Project Number: 1043W: 1043W-1: 1042W-004. Unpublished study prepared by PTRL West, 

Inc. 115 p. 

162-1 Aerobic soil metabolism

MRID Citation Reference

2935

98833

2009589

2009613

Chin, W.T.; Dannals, L.E.; Kucharczyk, N. (1972) Environmental Fate Studies on Vitavax^(R)I: 

Status Report on PR 70-15. (Unpublished study received Mar 6, 1972 under 2F1191; submitted by 

Uniroyal Chemical, Bethany, Conn.; CDL:093515-A) 

Kulge, E. 1969. The effect of the soil reaction on the degradation and persistence of thiuram, 

ferbam, and captan in the soil . A translation of : without title . Archivfurer pflanzens-chutz, 5(4):263-

271.

40768104 2009622 Daly, D.; Cranor, W. (1988) "Aerobic Soil Metabolism of ?Carbon 14|-Thiram": ABC Final Report 

#33569. Unpublished study pre- pared by Analytical Bio-Chemistry Laboratories, Inc. 1475 p. 

43734901 2009629 Morgenroth, U.; Mueller-Kallert, H. (1995) (Carbon 14)-Thiram: Degradation and Metabolism in One 

Soil Incubated Under Aerobic Conditions: Lab Project Number: 326182. Unpublished study 

prepared by RCC Umweltchemie Ag. 114 p. 

162-2 Anaerobic soil metabolism

MRID Citation Reference

2935 2009589

Vitavax = 

Carboxin

Chin, W.T.; Dannals, L.E.; Kucharczyk, N. (1972) Environmental Fate Studies on Vitavax^(R)I: 

Status Report on PR 70-15. (Unpub- lished study received Mar 6, 1972 under 2F1191; submitted by 

Uniroyal Chemical, Bethany, Conn.; CDL:093515-A) 

162-3 Anaerobic aquatic metabolism

MRID Citation Reference

40768103 2009621 Daly, D.; Cranor, W. (1988) Anaerobic Aquatic Metabolism of ?Carbon 14|-Thiram: ABC Final 

Report #33570. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 875 p. 
Page 40 of 60

43628501 2009627 Wyss-Benz, M. (1995) (Carbon 14)-Thiram: Degradation and Metabolism in an Anaerobic Aquatic 

System: Revised Report: Lab Project Number: 329635. Unpublished study prepared by RCC 

Umweltchemie AG. 110 p. 

162-4 Aerobic aquatic metabolism

MRID Citation Reference

45243401 2075949

2075950

2079014

Wyss-Benz, M. (1992) Degradation and Metabolism of Thiram in Aquatic Systems (Amended 

Report): Lab Project Number: 303456. Unpublished study prepared by RCC Umweltchemie Ag. 156 

p. 

163-1 Leach/adsorption/desorption

MRID Citation Reference

2935 Vitavax= 

Carboxin Chin, W.T.; Dannals, L.E.; Kucharczyk, N. (1972) Environmental Fate Studies on Vitavax^(R)I: 

Status Report on PR 70-15. (Unpublished study received Mar 6, 1972 under 2F1191; submitted by 

Uniroyal Chemical, Bethany, Conn.; CDL:093515-A) 

3151 DER not 

located

Mamadou, D. (1976) Evaluation of a Soil-Plate Screening Technique in Develop-ing Fungicidal 

Control for Southern Stem Rot of Pea- nuts. Master's thesis, North Carolina State Univ., Dept. of 

Plant Pathology. (Unpublished study including abstract, received Sep 13, 1976 under 400-129; 

submitted by Uniroyal Chemi- cal, Bethany, Conn.; CDL:225604-AA)

65859 2009615 

open lit

Helling, C.S., D.G. Dennison, and D.D. Kaufman. 1974. Fungicide movement in soils. 

Phytopathology 64(Aug):1091-1100. Also I n unpublished submission received Mar. 5,

1976 under 661754.

98839 2009614 

open lit

Munnecke, D.E. (1961) Movement of nonvolatile, diffusible fungicides through columns of soil. 

Phytopathology 51(Sep):593-599. (Also~In~unpublished submission received Jan 4, 1978 under 

239- 1246; submitted by Chevron Chemical Co., Richmond, Calif.; CDL: 232569-S) 

148178 DER not 

located

Bayer AG (1977) Pesticide Residue in Groundwater: [Pomarsol Forte 80 WP]: Study No. 8800/77. 

Unpublished translation. 1 p. 

148179 DER not 

located

Bayer AG (1977) Pesticide Residue in Groundwater: [Pomarsol Forte 80 WP]: Study No. 8801/77. 

Unpublished translation. 1 p. 

148180 DER not 

located

Bayer AG (1974) Pesticide Residue in Groundwater: [Pomarsol For- te]: Study No. 8803/74. 

Unpublished translation. 1 p. 

148181 DER not 

located

Bayer AG (1974) Pesticide Residue in Groundwater: [Pomarsol Forte]: Study No. 8804/74. 

Unpublished translation. 1 p. 

148182 DER not 

located

Bayer AG (1974) Pesticide Residue in Groundwater: [Pomarsol Forte]: Study No. 8805/74. 

Unpublished translation. 1 p. 

158665 DER not 

located

Warren, J.; Drury, P.; Connor, S. (1986) Determination of Adsorption/ Desorption Constants of 

[Carbon-14]-Thiram: ABC Final Report #33573. Unpublished study prepared by Analytical BioChemistry Laboratories, Inc. 334 p. 

5001190 DER not 

located

Helling, C.S.; Dennison, D.G.; Kaufman, D.D. (1974) Fungicide movement in soils. Phytopathology 

64(8):1091-1100. 

158665 DER not 

located

Warren, J.; Drury, P.; Connor, S. (1986) Determination of Adsorption/Desorption Constants of 

[Carbon-14]-Thiram: ABC Final Report #33573. Unpublished study prepared by Analytical BioChemistry Laboratories, Inc. 334 p. 

43787501 2009630 

2009640 

2009567

Morgenroth, U. (1995) Adsorption/Desorption of (carbon 14)- Thiram on Four Soils: Lab Project 

Number: 354780. Unpublished study prepared by RCC Umweltchemie AG. 80 p. 

47337902 DER not 

located

Nag, J. (2001) Aged-Soil Column Leaching of (Carbon 14)-Thiram in One Soil. Project Number: 

2000/090. Unpublished study prepared by Uniroyal Chemical Co., Inc., Agvise Inc. and Springborn 

Laboratories, Inc. 132 p.
Page 41 of 60

47495003 Contract 

Draft 

available

Reibach, P. (2008) Column Leaching of Radiolabeled Thiram in Five Soils. Project Number: 

KP/2008/02. Unpublished study prepared by JRF America. 66 p.

40768104 2009623 

2031960

2075951

Rockwell, J. C. 1986. Determination of Adsorption/Desorption Constants of 'C-Thiram. Performed 

by Analytical Bio-Chemistry Laboratories, Inc. submitted by

the Thiram Task Force. MRID 40768104,

164-1 Terrestrial field dissipation

MRID Citation Reference

2935 Vitavax = 

Carboxin 

DER not 

located

Chin, W.T.; Dannals, L.E.; Kucharczyk, N. (1972) Environmental Fate Studies on Vitavax^(R)I: 

Status Report on PR 70-15. (Unpublished study received Mar 6, 1972 under 2F1191; submitted by 

Uniroyal Chemical, Bethany, Conn.; CDL:093515-A) 

40768101 2009619 Selman, F.; Moezpoor, E. (1987) Terresterial Soil Dissipation of Thiram on Turf in Georgia: Final 

Report #34569. Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 1082 p. 

40953301 2009624 Selman, F. (1988) Terrestraial Soil Dissipation of Thiram on Turf in Missouri: Final Rept. #34570. 

Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 178 p. 

44724501 2009631 

2009638

2009633=E

CM method

Dykeman, R. (1998) Determination of the Dissipation of Residues of Thiram in California Turf and 

Bare Ground Plots Treated with Spotrete 75WDG: Lab Project Number: 95049: F96318-810: 95049-

CA1. Unpublished study prepared by Compliance Services International. 818 p. 

44724502 2009632 

2009639

Dykeman, R. (1998) Determination of the Dissipation of Residues of Thiram in North Carolina Turf 

and Bare Ground Plots Treated with Spotrete 75WDG: Lab Project Number: 95051: 95051-NC1: 

F96194-054. Unpublished study prepared by Compliance Services International. 1322 p. 

N/A 2009635 1996 Letter from registrant regarding Protocol for Terrestrial Field Study

Non Guideline Studies

MRID Citation Reference

N/A 2009612 Contract Draft – Environmental Fate and Exposure Assessment

N/A 2009633 Memo re Analytical Methods part of study report 44724501

N/A 2009634 

2031960 1991 EFED Fate Data Summary

N/A 2009636 Data Waiver for Irrigated Crop acculmulation and also submission of supplemental data for 

Photodegradation on Soil 

N/A 2009638

2009643

2009644

Thiram Lab Method Evaluation Report No. ECM 0151S1 for ECM for Thiram in Soil and ABC Labs 

summary of Method development

N/A 2009639 Thiram Lab Method Evaluation Report No. ECM 0151W1 for ECM for Thiram in Water

N/A 2009641

2009642 1991 and 1992 Fate Database One-liner reports

Not 

provided

2075951

2075952 1989 Dynamac Contract Draft Groundwater assessment and Mike Barrett’s response to Registrants

3151 Not an 

EFED 

guideline 

study

Mamadou, D. (1976) Evaluation of a Soil-Plate Screening Technique in Developing Fungicidal 

Control for Southern Stem Rot of Pea- nuts. Master's thesis, North Carolina State Univ., Dept. of 

Plant Pathology. (Unpublished study including abstract, received Sep 13, 1976 under 400-129; 

submitted by Uniroyal Chemi- cal, Bethany, Conn.; CDL:225604-AA)
Page 42 of 60

10.2. Submitted Ecological Toxicity Studies

MRID Citation

TN 1001 McCann, J.A. ,1976. Rainbow trout Test No. 1001. (U.S. Agricultural Research Service, Pesticides 

Regulation Div., Animal Biology Laboratory; With 99 % technical

TN 996 McCann, J.A. (1968: Bluegill (Lepomis macrochirus)|: Test No. 996. (U.S. Agricultural Research 

Service, Pesticides Regulation Div., Animal Biology Laboratory; With 99 % technical

00002923/ 

00021610

Mastri, C. (1970) Report to Uniroyal Chemical, Division of Uniroyal, Inc.: Four-Day Fish Toxicity 

Study on Three Samples of Vitavax Seed Protectants: IBT No. A8585. (Unpublished study received 

Feb 18, 1972 under 400-81; prepared by Industrial Bio-Test Laboratories, Inc., submitted by 

Uniroyal Chemical, Bethany, Conn.; CDL:003261-D) 

00003074 Heitmuller, T. (1975) Acute Toxicity of Vitavax to Pink Shrimp (Penaeus duorarum) and Fiddler 

Crabs (Uca pugilator). (Unpublished study received May 16, 1975 under 400-116; pre- pared by 

Bionomics--EG&G, Inc., submitted by Uniroyal Chemical, Bethany, Conn.; CDL:165048-A) 

00003308 Mastalski, K. (1970) Report to Uniroyal Chemical, Division of Uniroyal, Inc.: Acute Oral Toxicity 

Study on Vitavax Seed Protectant with Thiram in Bobwhite Quail: IBT No. J8584. (Unpublished 

study received May 8, 1972 under 2F1191; prepared by Industrial Bio-Test Laboratories, Inc., 

submitted by Uniroyal Chemical, Bethany, Conn.; CDL:091003-C) 

00022293 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 Wildlife Research Center; unpublished report)

00036935 Atkins, E.L.; Greywood, E.A.; Macdonald, R.L. (1975) Toxicity of Pesticides and Other 

Agricultural Chemicals to Honey Bees: Laboratory Studies. By University of California, Dept. of 

Entomology. UC, Cooperative Extension. (Leaflet 2287; published study.)

00073683/ 

00020560

Schafer, E.W. (1972) The acute oral toxicity of 369 pesticidal, pharmaceutical and other chemicals 

to wild birds. Toxicology and Applied Pharmacology 21(? ):315-330. (Also in unpublished 

submission received Apr 25, 1978 under 476-2180; submitted by Stauffer Chemical Co., Richmond, 

Calif.; CDL:233577-C

0007368 / 

00020560

Schafer, E.W. (1972) The acute oral toxicity of 369 pesticidal, pharmaceutical and other chemicals 

to wild birds. Toxicology and Applied Pharmacology 21(? ):315-330. (Also in unpublished 

submission received Apr 25, 1978 under 476-2180; submitted by Stauffer Chemical Co., Richmond, 

Calif.; CDL:233577-C

00090293 McCann, J.A. (1972) Tersan 75: Rainbow trout. Test No. 463. (U.S. Agricultural Research Service, 

Pesticides Regulation Div., Animal Biology Laboratory, Fish Toxicity Laboratory; unpublished 

study; CDL:130512-A)

00090294 McCann, J.A. (1972) Tersan 75: Bluegill sunfish. Test No. 446. (U.S. Agricultural Research 

Service, Pesticides Regulation Div., Animal Biology Laboratory, Fish Toxicity Laboratory; 

unpublished study; CDL:130513-A) 

00152556 Debets, F. (1985) Evaluation of the Acute Inhalation Toxicity of TMTD Technical in the Rat: 

NOTOX 0113/232. Unpublished study prepared by Notox V. O. F. 17 p.

00153548 Thouin, M. (1985) Evaluation of the Acute Oral Toxicity of TMTD Technical in the Rat: Study No. 

0174/238. Unpublished study prepared by Notox v.o.f Hambakenwetering 31. 19 p.

00154264 Van Leeuwen, C. (1985) The Toxicological Consequences of the Use of Dialkyldithiocarbamates 

for Some Softwater Organisms. Unpublished translation of journal article with related data prepared 

by RIZA Ecotoxicology Laboratory. 14 p.

00160000 Hudson, R.; Tucker, R.; Haegele, M. (1984) Handbook of toxicity of pesticides to wildlife: Second 

edition. US Fish and Wildlife Service: Resource Publication 153. 91 p.

00164662 Husson, R. (1986) Letter sent to J. Rockwell dated Sept 17, 1986: [Data requested to complete 

review of 48 hour LC50 study on Daphnia magna: thiram]. Prepared by UCB Societe Anonyme. 3 

p. 
Page 43 of 60

05020144 Tooby, T.E., Hursey, and Alabaster. 1975. The acute toxicity of 102 pesticides and miscellaneous 

substances to fish. Chemistry and Industry (21):523-526.

40216501 Maedgen, J.; Lain, D. (1987) Rat Acute Inhalation Toxicity: [Thiram Technical]: Laboratory Project 

ID: 4730-87. Unpublished study prepared by Stillmeadow, Inc. 19 p.

42095901 York, R. (1991) Two-Generation Reproduction Study in Rats Using Thiram: Lab Project Number: 

399-104. Unpublished study pre- pared by International Research and Development Corp. 764 p.

42488301 Thompson, R.; Croudace, C.; Grinell, A. (1992) Thiram: Acute Toxicity to Larvae of the Pacific 

Oyster (Crassostrea gigas): Lab Project Number: W199/C: BL4547/B. Unpublished study prepared 

by Imperial Chemical Industries PLC. 20 p. 

42488302 Thompson, R.; Croudace, C.; Grinell, A. (1992) Thiram: Acute Toxicity to Mysid Shrimp 

(Mysidopsis bahia): Lab Project Number: W199/D: BL4562/B. Unpublished study prepared by 

Imperial Chemical Industries PLC. 19 p. 

42514401 Croudace, C.; Caunter, J.; Johnson, P. (1992) Thiram: Acute Toxicity to Sheepshead Minnow 

(Cyprinodon variegatus): Lab Project Number: W199/B. Unpublished study prepared by Imperial 

Chemical Industries PLC. 22 p. 

42646001 Douglas, M. (1993) Thiram: Algal Growth Inhibition (Selenastrum capricornutum): Lab Project 

Number: UCB 442/921255. Unpublished study prepared by Huntingdon Research Centre Ltd. 30 p. 

43612501 Beavers, J.; Chafey, K.; Mitchell, L. et al. (1995) Thiram Technical: A Reproduction Study with the 

Mallard: Lab Project Number: 357/104: CHR24. Unpublished study prepared by Wildlife 

International Ltd. 278 p. 

43612502 Beavers, J.; Chafey, K.; Mitchell, L. et al. (1995) Thiram Technical: A One Generation 

Reproduction Study with the Northern Bobwhite (Colinus virginianus): Amended: Lab Project 

Number: 357/103: CHR24. Unpublished study prepared by Wildlife International Ltd. 250 p. 

43612505 Beavers, J.; Haberlein, D.; Grimes, J. et al. (1995) Thiram Technical: A Palatability/Repellancy 

Study with the Mallard (Anas platyrhynchos) Under Multiple Choice Conditions: Lab Project 

Number: 357/106: CHR17. Unpublished study prepared by Wildlife International Ltd. 183 p. 

43612506 Beavers, J.; Haberlein, D.; Grimes, J. et al. (1995) Thiram Technical: A Palatability/Repellancy 

Study with the Northern Bobwhite (Colinus virginianus) Under Multiple Choice Conditions: Lab 

Project Number: 357/105: CHR17. Unpublished study prepared by Wildlife International Ltd. 184 

p. 

44086101 Coates, M. (1996) Thiram: Algal Growth Inhibition: Addendum to MRID 426460-01: Lab Project 

Number: UCB 442/960953: UCB 442/921255. Unpublished study prepared by Huntingdon Life 

Sciences, Ltd. 10 p. 

45441201 Gallagher, S.; Martin, K.; Beavers, J. (2001) Thiram Technical: A Reproduction Study with the 

Mallard: Final Report: Lab Project Number: 357-107. Unpublished study prepared by Wildlife 

International, Ltd. 143 p. 

45441202 Sutherland, C.; Kendall, T.; Krueger, H. (2001) Thiram Technical: A 7-Day Toxicity Test with 

Duckweed (Lemna gibba G3): Final Report: Lab Project Number: 357A-101. Unpublished study 

prepared by Wildlife International. Ltd. 79 p. 

45441203 Turck, P. (1997) Two Generation Reproduction/Fertility Study in Rats with Thiram: Lab Project 

Number: 399-180. Unpublished study prepared by MPI Research. 1579 p.

46249301 Peither, A. (2000) Acute Toxicity of Thiram Technical to Rainbow Trout (Oncorhynchus mykiss) in 

a 96-Hour Static Test. Project Number: 775552. Unpublished study prepared by VJP Consulting, 

Inc. and RCC Ltd. 46 p.

46249303 Memmert, U. (2001) Sublethal Effects of Thiram 80 WG to Rainbow Trout (Oncorhynchus mykiss) 

After a Fourfold Application to a Water-Sediment System. Project Number: 8043363. Unpublished 

study prepared by RCC Umweltchemie Ag. 60 p.

46249304 Memmert, U. (2000) Ecological Effects of Thiram 80 WG in A Freshwater Mesocosm Study. 

Project Number: 733454. Unpublished study prepared by RCC Ltd. and Aachen Univ. of 

Technology. 319 p.
Page 44 of 60

47495001 Krueger, H.; Kendall, T. (2008) (Carbon 14)-Thiram: A Flow-Through Life-Cycle Toxicity Test 

with the Cladoceran (Daphnia magna): Final Report. Project Number: 657A/101. Unpublished study 

prepared by Wildlife International, Ltd. 59 p.

47495002 Krueger, H.; Kendall, T. (2008) (Carbon 14)-Thiram: An Early Life-Stage Toxicity Test with the 

Fathead Minnow (Pimephales promelas): Final Report. Project Number: 657A/102. Unpublished 

study prepared by Wildlife International, Ltd. 70 p.

47824101 Krueger, H.; Kendall, T. (2009) (Carbon 14)-Thiram: A Flow-Through Life-Cycle Toxicity Test 

with the Fathead Minnow (Pimephales promelas): Final Report. Project Number: 657A/103. 

Unpublished study prepared by Wildlife International, Ltd. 144 p.
Page 45 of 60

Appendix A. SIP Modeling Results

Table 1. Inputs

Parameter Value

Chemical name Thiram

Solubility (in water at 25oC; mg/L) 16.5

Mammalian LD50 (mg/kg-bw) 1800

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Mammalian NOAEL (mg/kg-bw) 1.4

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Avian LD50 (mg/kg-bw) 673

Avian test species other

Body weight (g) of "other" avian species 1135

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 9.6

Bobwhite quail NOAEC (mg/kg-diet)

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 2.8380 2.8380

Adjusted toxicity value (mg/kg-bw) 1384.4890 1.0768

Ratio of exposure to toxicity 0.0020 2.6355

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Exposure through 

drinking water alone is a 

potential concern for 

mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 13.3650 13.3650

Adjusted toxicity value (mg/kg-bw) 367.2148 0.4763

Ratio of exposure to acute toxicity 0.0364 28.0612

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Exposure through 

drinking water alone is a 

potential concern for 

birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. 

Therefore, when aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through 

drinking water may contribute to a total exposure that has potential for effects to non-target animals.
Page 46 of 60

Appendix B. STIR Modeling Results

Input

Application and Chemical Information

Enter Chemical Name Thiram

Enter Chemical Use Fungicide

Is the Application a Spray? (enter y or n) y

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 240.44

Enter Chemical Vapor Pressure (mmHg) 1.73E-05

Enter Application Rate (lb a.i./acre) 16.3

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 673

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 1.135

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 1800

Enter Lowest Rat Inhalation LC50 (mg/L) 2.6

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 2.24E-01

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.81E-02

Adjusted Inhalation LD50 4.11E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 6.85E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.72E+00

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 4.20E-01 Proceed to Refinements

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 2.24E-01

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.54E-02

Adjusted Inhalation LD50 1.55E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.29E-04 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 2.17E+00

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 1.40E-02 Exposure not Likely Significant
Page 47 of 60

Appendix C. Summary of Ferbam and Thiram Fate and 

Transport Data

I. Abiotic Degradation

161-1 Hydrolysis (MRID 44071801, Acceptable) – [

14C]Ferbam (dimethyldithiocarbamic acid, 

iron salt) hydrolyzed at ∼25.0 ̊C with pH-dependent rates, increasing with pH. The half-life at 

pH 9 could not be assessed because the hydrolysis was too rapid for the type of monitoring 

equipment utilized (full hydrolysis occurred within 10 seconds).

Table A-1. Ferbam hydrolysis rate.

pH Initial concentration (ppm) Half-life (minutes) r

2 

5 10 12.1 0.991

7 50 7.8 0.941

9 50 <0.2 N/A

Table A-2. Ferbam hydrolysis byproducts.

[14C]Ferbam (dimethyldithiocarbamic acid, iron salt), at 9.9 ppm, hydrolyzed and photodegraded

too fast to allow the assessment of the photolysis rate. The hydrolysis/photolysis half-life was 

found to be 31.0 minutes (r2 = 0.969). The media was continuously exposed to light from a xenon 

arc lamp for 15 days forming volatile products and thiram. The main difference in degradation 

between irradiated and dark samples was the rate and extent of formation of volatile products.

Sterilized deionized ultra-filtered (DIUF) water was used in this study. It appears that the 

samples were not buffered at any specified pH. The initial pH was about 6 and decreased 

throughout the study for both the dark control and the exposed sample. The irradiated samples 

pH decreased to an average of 4.5 at 15 days, while the dark control samples pH did not change 

as much, remaining at an average of 5.8 after 15 days. The study author suggests that the pH of 

test solutions became more acidic indicating the formation of acidic products. The previous study 

indicated that the half-lives for hydrolysis of ferbam at pHs 5–7 did not differ much, with rates of 

about 8–12 minutes.

The major degradates of ferbam were volatile, mainly CS2 (44.6% of the applied), and CO2

(28.6%). Following 15 days of incubation, volatile products accounted for 73.6% of the applied 

radioactivity for irradiated samples compared to 31.4% for dark samples. Degradation to volatile 

products was rapid in dark samples through day 2 but slowed thereafter, whereas in irradiated 

samples, degradation to volatile products continued. The major non-volatile degradate was 

tetramethylthiuram disulfide (TMTD) which accounted for a maximum of 63.3% of the applied 

radioactivity at day 1, and decreased to 1.1% by day 7 and 0.5% of the applied radioactivity at 

day 15. The degradation half-life for TMTD was 4.7 days.

A difference in the degradation pattern between irradiated and dark samples was the rate and 

extent degradation of thiram, and of formation of volatile products. In the dark controls, thiram 

was a maximum of 73.1% at day 1, and decreased more slowly (compared to the irradiated 

sample) to 61.1% of the applied radioactivity by day 15 post-treatment. For dark samples, CS2

accounted for 27.3% of the applied radiocarbon and 3.5% CO2.
Page 48 of 60

Two additional products were found exceeding 10% of the applied radiocarbon, designated as A 

and B and characterized as polar, water soluble and acidic in nature. Degradate A increased from 

7.7% of the applied radiocarbon (day 1) to a maximum of 16.0% (day 3) then decreased to 9.0% 

following 15 days of irradiation; degradate B, found only in significant amounts in the irradiated 

samples, increased from 1.4% (day 2) to a maximum of 11.9% of applied radiocarbon on day 15.

161-3 Photodegradation on Soil (MRID 43999802, Acceptable) – [

14C]Ferbam 

(dimethyldithiocarbamic acid, iron salt) was applied to a sandy loam soil, at 12.2 ppm. The soil 

was irradiated continuously with a UV-filtered xenon arc light source for up to 15 days at 25 ̊C 

and 75% of FMC at 1⁄3 bar (maintained concurrently with a dark control).

It appears that parent ferbam degraded so quickly that even immediately post-treatment, the only 

degradate extractable both from the irradiated sample and the dark control was Thiram. The rate 

of degradation appeared to be similar for Thiram in both irradiated sample and dark control. 

Thiram was the only extractable degradate for irradiated and dark samples. This degradate (in 

irradiated samples) comprised a mean of 82.5% of the applied radioactivity at day 0 (84.5% dark 

control), and 17.2% at day 15 (20.7% dark).

On the other hand, the amount of volatiles and their relative proportion was much more different. 

Following 15 days of incubation, volatile products accounted for 38.5% of the applied 

radioactivity for irradiated samples and 15.8% for dark control samples. Major volatile 

degradates in the irradiated and dark samples were 14CO2, and 14CS2. After 15 days of 

incubation, 14CS2 comprised of 44.6% of the applied radioactivity in the irradiated samples and 

27.3% in the dark control samples. After 15 days of incubation, 14CO2 comprised of 28.6% of 

the applied radioactivity in the irradiated samples and 3.5% in the dark control samples.

161-4 Photolysis in Air (Waived) – The data requirement is waived. The rapid rate of 

degradation in soil and water and the relatively low volatility of ferbam, suggest that atmospheric 

photolysis is not likely to be an important route of dissipation.

II. Metabolism

162-1 Aerobic Soil Metabolism (MRID 44368901, Acceptable) – [

14C]Ferbam, at 11.2 ppm, 

and incubated in the dark on an aerobic sandy loam soil at about 25 ̊C and 75% of 1⁄3 bar (75% of 

field capacity) for up to 150 days, degraded very rapidly and the degradation rate of the parent 

compound could not be assessed under the conditions of the study. The primary degradate was 

tetramethylthiuram (TMTD), which was a mean (of two replicates) of 77.9% of the applied 

radioactivity at the initial test interval (0 hours). TMTD (also commonly known as thiram), 

degraded further, with a half-life of 4.9 days. Thiram comprised a mean (2 replicates) of 77.9% 

of the applied radioactivity at hour 0, 67.1% at hour 4, 50.1% at day 1, 43.8% at day 2, 33.9% at 

day 4, 23.4% at day 7, 17.3% at day 14, 15.3% at day 21, 7.7% at day 45, 5.8% at day 93, and 

2.6% at day 150.

Volatile metabolites included CO2 (accounted for 56.4% of the initially applied radiocarbon at 

150 days post-treatment), and 14CS2 (accounted for 5.5% of the initially applied radiocarbon at 

150 days post-treatment). Several minor degradates were observed none of which exceeded 

1.2% of the applied radiocarbon. Soil bound residue reached a maximum of 49.9% (mean of two 
Page 49 of 60

replicates) of the applied radiocarbon at day 7, then decreased to 26.3% by day 150. Material 

balances ranged from 90.5% to 101.6% of the initially applied radioactivity.

162-2 Anaerobic Soil Metabolism (MRID 44565305, Acceptable) – [

14C]Ferbam, at 11.6 ppm, 

and incubated in the dark on an anaerobic sandy loam soil at about 25 ̊C for up to 364 days, 

degraded very rapidly and the degradation rate of the parent compound could not be assessed 

under the conditions of the study.

One primary degradate was tetramethylthiuram (TMTD, thiram), which was a mean (of two 

replicates) of 33.8% of the applied radioactivity at the initial test interval (0 hours). Thiram 

degraded further, with a half-life of 184 days. Thiram accounted for 33.8% (mean of 2 

replicates) of the applied radiocarbon, following dosing, 28.1% at day 3, 30.2% at day 7, 27.9% 

at day 14, 15.7% at day 21, 17.5% at day 51, 16.8% at day 93, 8.9% at day 134, 7.4% at day 182, 

10.9% at day 272, and 8.1% at day 364.

One other major degradate was Co-DMDTC [cobalt (II)dimethyldithiocarbamate], which was a 

mean (of two replicates) of 39.6% of the applied radioactivity at the initial test interval (0 hours). 

Co-DMDTC, degraded further, with a half-life of 269 days. Co-DMDTC reached a level of 

39.6% (a mean of two replicates) of the applied radiocarbon, 38.3% at day 3, 40.9% at day 7, 

41.8% at day 14, 46.5% at day 21, 36.2% at day 51, 31.2% at day 93, 36.9% at day 134, 29.1% 

at day 182, 18.3% at day 272, and 16.8% at day 364.

A total of five unknown degradates were detected, of which only one degradate was observed at 

a level >10% of the applied radiocarbon. This degradate comprised 11.7% (mean of two 

replicates) of the applied radiocarbon at day 0 in the water samples, then decreased to 2.8% by 

day 7. Following day 7, the water samples were not analyzed due to low levels of radiocarbons 

(≤3% of the applied radiocarbon). Soil-bound residue ranged from 11.0 to 16.1% (mean of 

replicates) of the applied radiocarbon between Day 0 and Day 182 and decrease to 6.6 and 5.6% 

(mean of replicates) on Day 272 and 364, respectively.

The major volatile metabolites formed during this Anaerobic Metabolism were CS2 and CO2

which accounted for a total of 50.7% and 7.5% of the initially applied radioactivity, respectively.

The overall material balance throughout the study was 95.8± 5.2 (mean± standard deviation) of 

the applied radiocarbon.

III. Specific Mobility and Persistence Data for Ferbam

163-1 Mobility Batch Equilibrium – Adsorption/Desorption (MRID 40088204, 

Unacceptable) – This study does not satisfy the data requirement for ferbam. It cannot be used 

to satisfy the mobility in soil data requirement for ferbam because the soils were sterilized by 

autoclaving at 121 ̊C and 15 psi. In addition, no attempt was made to account for volatiles, 

resulting in a very low mass balance for all soils used in this study. The mobility of 14C-ferbam 

was studied at a concentrations of 0.1, 0.5, 1.0, and 5.0 ppm in sieved (2 mm) and sterilized 

sandy loam, silt loam, sand, and clay loam. Adsorption coefficients ranging from 3.57 to 22.9 

were measured, which corresponded to Koc values ranging from 432 to 2207.
Page 50 of 60

EFED acknowledges the difficulty to conduct a scientifically sound batch equilibrium study for 

ferbam since it is very unstable under hydrolytic and under aerobic conditions. Furthermore, the 

available studies indicate that parent ferbam is not likely to persist enough to present a 

significant risk of contamination of surface or groundwater. Therefore, no new studies will be 

required for the parent compound.

163-1 Mobility Batch Equilibrium – Adsorption/Desorption (MRID 43787501, 

Supplemental) – At this time, EFED has a batch equilibrium study for thiram, the major nonvolatile degradation product of ferbam. However, this study was deemed supplemental.

14C-thiram at concentrations of 0.01, 0.04, 0.20, and 1.07 mg/L was determined to have low 

mobility in a sandy loam and silt loam soil, and was immobile in loamy sand and loamy silt soils. 

Freundlich adsorption coefficients were 54, 150, 67, and 263 for the sandy loam, loamy sand, silt 

loam and loamy silt, respectively. Corresponding Koc values were 2,245 (sandy loam), 24,526 

(loamy sand), 6,359 (silty loam), and 12,899 (loam silt). The data from this study including the 

properties of each soil are shown in Table A-3.

Table A-3. Thiram soil adsorption and mobility characteristics.

a

Soil 

characteristics

Sandy loam, 

NY

Loamy sand, IL Silt loam, IL Loam, IA

% Clay 14.8 7.5 16.8 25.2

% Silt 29.6 9.4 59.1 33.6

% Sand 55.6 83.1 24.1 41.2

% Organic carbon 2.41 0.61 1.06 2.04

pH 6.7 4.8 6.7 7.3

Kd 54 150 67 263

Koc 2245 24526 6359 12899 a

MRID 04378501

163-2 Laboratory Volatility – No data are required due to the relatively low vapor pressure of 

ferbam. 

163-3 Field Volatility – No data are required due to the relatively low vapor pressure of ferbam.

IV. Field Dissipation

Since ferbam appears to be very labile in the environment, as shown in the aerobic soil 

metabolism study (MRID 44368901), and its major degradation product is thiram, two terrestrial 

field dissipation studies for thiram (MRID 44724501 and 44724502) will be used as surrogate 

studies for the ferbam data requirement.

164-1 Terrestrial Field Dissipation of Ferbam (MRID 40550902, 40603401 Unacceptable) 

Peach field located in Donalsville, GA, and an apple orchard in Waterloo, NY were considered 

not acceptable and do not satisfy the data requirement for ferbam because they do not provide 

information about the degradation, mobility or any other dissipation avenues for the parent under 

actual use conditions. Additionally, a major degradate, thiram, expected to be formed in the 

field, was not addressed in the study. 
Page 51 of 60

164-1 Terrestrial Field Dissipation of Thiram (MRID 44724501, Supplemental, and 

44724502, Acceptable) – Thiram was applied eight times at a nominal rate of 10.3 lbs a.i./A to 

turfed and bare plots of an alkaline sandy soil (pH 8.2 to 9.6) in California. The terrestrial field 

half-life was 27.4 days in a turfed plot and 14.4 days from a bareground plot. A similar study 

conducted using an acidic bareground sandy soil (pH 4.1 to 4.7) and acidic turfed loamy sand 

(pH 4.4 to 4.5) in North Carolina where thiram was applied eight times at a rate of 10.3 lbs 

a.i./A/application yielded slightly longer half-lives. The field half-life was 36 days on the 

bareground plot and 62.5 days on the turfed plot.
Page 52 of 60

Appendix D. Ziram, Thiram, and Ferbam Ecotoxicity Data

1. Toxicity to Aquatic Organisms

1.1. Aquatic Vertebrate Toxicity

1.1.1. Freshwater Fish Toxicity

Table A-1. Acute Toxicity to Freshwater Fish

Species % ai 96-hr LC50

(ppm ai)

Toxicity 

Category

MRID No.

Author, Year

Study 

Classification

FERBAM

Bluegill sunfish 

(Lepomis macrochirus) 95 3.6 Moderately toxic

05014941

Pickering & 

Henderson, 1966

Supplemental

Carp (Cyprinus carpio) Tech 0.09 Very highly toxic

05001997

Hashimoto & 

Fukami, 1969

Supplemental

Fathead Minnow 

(Pimephales promelas) 95 3.1 Moderately toxic

05014941

Pickering & 

Henderson, 1966

Supplemental

THIRAM

Bluegill sunfish 99.0 0.042 Very highly toxic TN 996

McCann, 1968 Acceptable

Bluegill sunfish 37.5 0.21 1 Highly toxic 00002923, 00021610

Mastri, 1970 Supplemental

Bluegill sunfish 75 0.28 Highly toxic 00090294 

McCann, 1972 Supplemental

Harlequin Fish (Rasbora 

heteromorpha) 80 0.007 Very highly toxic 05020144Tooby et al., 1975 Supplemental

Rainbow trout 

(Oncorhynchus mykiss) 99.0 0.046 Very highly toxic 46249301Peither, 2000 Supplemental

Rainbow trout 99.0 0.128 Highly toxic TN 1001

McCann, 1976 Acceptable

Rainbow trout 37.5 0.14 1 Highly toxic 00002923, 00021610

Mastri, 1970 Supplemental

Rainbow trout 75 0.382 Highly toxic 00090293

McCann, 1972 Supplemental

ZIRAM

Bluegill sunfish 98.9 0.0097 Very highly toxic 42386303

Douglas et al., 1991 Acceptable

Bluegill sunfish 98.2 0.57 Highly toxic 47307901

Palmer et al., 2007 Acceptable

Carp Tech 2.28 Moderately toxic

00138215

Dickhaus & Heisler, 

1980

Supplemental

Fathead Minnow 99.0 0.008 Very highly toxic

05003523

Maloney & Palmer, 

1956

Supplemental

Rainbow trout 76 0.23 Highly toxic TN 1021

McCann, 1976 Supplemental
Page 53 of 60

Species % ai 96-hr LC50

(ppm ai)

Toxicity 

Category

MRID No.

Author, Year

Study 

Classification

Rainbow trout Tech 0.27 Highly toxic 00138214

Dickhaus et al., 1980 Supplemental

Rainbow trout 98.9 1.7 Moderately toxic 42386304

Douglas et al., 1991 Acceptable

1 Test substance: Vitavax Seed Protectant, 37.5% thiram and 37.5% carboxin

Table A-2. Chronic Toxicity to Freshwater Fish

Species % ai NOAEC / LOAEC

(ppm ai)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM

Fathead Minnow 

(Pimephales promelas) 98.7 0.0011 / 0.0022 1

F0 % spawning 

frequency, F0 egg 

production, F1 

time to hatch, F1 

4-wk survival 

47824101

Krueger & Kendall, 

2009

Acceptable

Rainbow Trout 

(Oncorhynchus mykiss) 81.2 0.012 / 0.020 2 Growth rate 46249303Memmert, 2001 Supplemental

ZIRAM

Fathead Minnow 98.2 0.101 / 0.195 3 Post-hatch 

survival

46893104

Palmer et al., 2006 Acceptable

Fathead Minnow 98.2 0.024 / 0.051 4 F0 length and 

weight

47435501

Palmer et al., 2008 Supplemental

1 Full life cycle study, 210 days.

2 Non-guideline 28-day sub-chronic study. 4 applications at 7 day intervals to 10:1 water:sediment systems. 3 Early-life stage study, 33 days (28 days post-hatch). 4 Full life cycle study, 275 days.

1.1.2. Estuarine/Marine Fish Toxicity

Table A-3. Acute Toxicity to Estuarine/Marine Fish

Species % ai 96-hr LC50

(ppm ai)

Toxicity 

Category

MRID No.

Author, Year

Study 

Classification

FERBAM

Longnose killifish 

(Fundulus similis) 76 0.80 Highly toxic 40228401Mayer, 1986 Supplemental

THIRAM

Sheepshead Minnow 

(Cyprinodon variegatus) 98.3 0.54 Highly toxic 42514401Croudace et al., 1992 Acceptable

ZIRAM

Longnose killifish Tech 6.40 1 Moderately toxic 40228401

Mayer, 1986 Supplemental

Sheepshead Minnow 98.9 0.84 Highly toxic 43781601

Machado, 1995 Acceptable

1 48-hr test
Page 54 of 60

Table A-4. Chronic Toxicity to Estuarine/Marine Fish

Species % ai NOAEC / LOAEC

(ppm ai)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM

No data available

ZIRAM

Sheepshead Minnow 98.2 0.027 / 0.058 1 Length and dry 

weight of larvae

46856401

Sutherland et al., 

2006

Acceptable

1 Early-life stage study, 34 days (28 days post-hatch).

1.2. Aquatic Invertebrate Toxicity

1.2.1. Freshwater Invertebrate Toxicity

Table A-5. Acute Toxicity to Freshwater Invertebrates

Species % ai 48-hr EC50

(ppm ai)

Toxicity 

Category

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM

Water flea (Daphnia 

magna) 98 0.21 Highly toxic 00164662Husson, 1986 Acceptable

ZIRAM

Water flea 98.9 0.048 Very highly toxic 42386305

Douglas et al., 1992 Acceptable

Water flea 98.2 0.206 Highly toxic 47405701

Palmer et al., 2008 Acceptable

Table A-6. Chronic Toxicity to Freshwater Invertebrates 

Species % ai NOAEC / LOAEC

(ppm ai)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM

Water flea 98.7 0.020 / 0.040

Dry weight, 

clinical signs of 

toxicity

47495001

Krueger & Kendall, 

2008

Acceptable

ZIRAM

Water flea 98.2 0.039 / 0.078 Length 46823301

Palmer et al., 2006 Acceptable
Page 55 of 60

1.2.2. Estuarine/Marine Invertebrate Toxicity

Table A-7. Acute Toxicity to Estuarine/Marine Invertebrates

Species % ai 96-hr EC50 or LC50

(ppm ai)

Toxicity 

Category

MRID No.

Author, Year

Study 

Classification

FERBAM

Eastern Oyster 

(Crassostrea virginica) 76 0.052 Very highly toxic 40228401Mayer, 1986 Supplemental

Pink Shrimp (Penaeus 

duorarum) 76 >40 1 Slightly toxic 40228401Mayer, 1986 Supplemental

THIRAM

Pacific Oyster 

(Crassostrea gigas) 98.3 0.0047 1 Very highly toxic

42488301

Thompson et al., 

1992

Acceptable

Mysid Shrimp 

(Americamysis bahia)

98.3 0.00336 Very highly toxic

42488302 

Thompson et al., 

1992

Acceptable

ZIRAM

Eastern Oyster 98.0 0.077 Very highly toxic 43781602

Dionne, 1995 Acceptable

Eastern Oyster Tech 1.00 Highly toxic 40228401

Mayer, 1986 Supplemental

Mysid Shrimp 98.0 0.014 Very highly toxic 43781603

Machado, 1995 Acceptable

Mysid Shrimp 98.2 0.14 Highly toxic 47405702

Palmer et al., 2008 Acceptable

Pink Shrimp Tech >5 1 Moderately toxic 40228401

Mayer 1986 Supplemental

1 48-hr test

Table A-8. Chronic Toxicity to Estuarine/Marine Invertebrates 

Species % ai NOAEC / LOAEC

(ppm ai)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

FERBAM

Mysid Shrimp 97.6 <0.0012 / 0.0012 F0 body length 47784401

Gallagher et al., 2009 Supplemental

THIRAM

No data available

ZIRAM

Mysid Shrimp 98.2 0.016 / 0.027 Reproduction and 

dry weight

46893103

Sutherland et al., 

2006

Supplemental

1.3. Aquatic Plant Toxicity

Table A-9. Toxicity to Aquatic Plants 

Species % ai EC50

(ppm ai)

EC05 or NOAEC

(ppm ai)

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM
Page 56 of 60

Species % ai EC50

(ppm ai)

EC05 or NOAEC

(ppm ai)

MRID No.

Author, Year

Study 

Classification

Duckweed (Lemna 

gibba) 98.7 7-d EC50 = 1.6 NOAEC < 0.057

45441202

Sutherland et al., 

2001

Acceptable

Green algae 

(Pseudokirchneriella 

subcapitata)

99.0 120-hr EC50 = 0.14 EC05 = 0.003 44086001, 44086101

Coates, 1996 Acceptable

ZIRAM

Duckweed 98.2 7-d EC50 = 0.37 NOAEC = 0.035

46823302

Desjardins et al., 

2006

Acceptable

Green algae 98.0 120-hr EC50 = 

0.067 NOAEC < 0.038 43833901Hoberg, 1995 Acceptable

2. Toxicity to Terrestrial Organisms

2.1. Avian Toxicity 

Table A-10. Acute Oral Toxicity to Birds

Species % ai LD50

(mg ai/kg-bw)

Toxicity 

Category

MRID

Author, Year

Study

Classification

FERBAM

No data available

THIRAM

Mallard duck (Anas 

platyrhynchos) 99.0 >2800 Practically nontoxic

00160000

Hudson et al., 1984 Acceptable

Red-wing blackbird 

(Agelaius phoeniceus) Tech >100 Moderately toxic 00073683, 00020560Schafer, 1972 Supplemental

Ring-neck pheasant 

(Phasianus colchicus) 99.0 673 Slightly toxic 00160000Hudson et al., 1984 Supplemental

Starling (Sturnus 

vulgaris) Tech >100 Moderately toxic 00073683, 00020560Schafer, 1972 Supplemental

ZIRAM

Bobwhite quail (Colinus 

virginianus) 98.5 97 Moderately toxic

41725701

Hakin & Norman, 

1989

Acceptable

Table A-11. Sub-acute Dietary Toxicity to Birds

Species % ai LC50

(mg ai/kg-diet)

Toxicity 

Category

MRID

Author, Year

Study 

Classification

FERBAM

Bobwhite quail Tech 2940 Slightly toxic 00106146

Fink & Reno, 1973 Supplemental

Mallard duck Tech >4640 Slightly toxic 00106148 

Fink & Reno, 1973 Supplemental

THIRAM

Bobwhite quail 95.0 3950 Slightly toxic 00022293

Hill et al., 1975 Acceptable
Page 57 of 60

Species % ai LC50

(mg ai/kg-diet)

Toxicity 

Category

MRID

Author, Year

Study 

Classification

Japanese quail (Coturnix 

japonica) 95.0 >5000 Practically nontoxic

00022293

Hill et al., 1975 Supplemental

Mallard duck 95.0 >5000 Practically nontoxic

00022293

Hill et al., 1975 Acceptable

Ring-neck pheasant 95.0 >5000 Practically nontoxic

00022293

Hill et al., 1975 Supplemental

ZIRAM

Bobwhite quail 98.5 >5200 Practically nontoxic

42386301

Hakin et al., 1992 Acceptable

Mallard duck 98.5 5156 Practically nontoxic

42386302

Hakin et al., 1992 Acceptable

Table A-12. Chronic Toxicity to Birds 

Species % ai NOAEC / LOAEC

(mg ai/kg-diet)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM

Bobwhite quail 97.5 500 / 2500

Egg production, 

eggs set/eggs laid, 

viable embryos/ 

eggs set, normal 

hatchlings/eggs 

set, 14-d 

survivors/eggs set, 

feed consumption, 

14-d survivor 

bodyweight, hen 

bodyweight

43612502

Beavers et al., 1995 Acceptable

Mallard duck 97.5 <50 / 50

Egg production, 

eggs set/eggs laid, 

normal hatchlings/ 

eggs laid

43612501 

Beavers et al., 1995 Supplemental

Mallard duck 98.7 9.6 / 39.7

Eggs set, viable 

embryos, live 3-

week embryos, 

normal hatchlings, 

14-d survivors, 

eggs set/eggs laid, 

normal hatchlings/ 

live 3-wk 

embryos, normal 

hatchlings/eggs 

laid

45441201

Gallagher et al., 2001 Acceptable
Page 58 of 60

Species % ai NOAEC / LOAEC

(mg ai/kg-diet)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

ZIRAM

Mallard duck 98.8 29 / 64

Eggs set, eggs set/ 

eggs laid, embryo 

viability, 

hatchability, 14-

day survivors, 14-

day survivors/ 

eggs set

47286501

Temple et al., 2007 Acceptable

2.2. Mammalian Toxicity 

Table A-13. Acute Oral Toxicity to Mammals

Species % ai LD50

(mg ai/kg-bw)

Toxicity 

Category

MRID

Author, Year

Study 

Classification

FERBAM

Laboratory rat

(Rattus norvegicus) 91.8 >5,000 Practically nontoxic

40561501

Reijnders, 1987 Acceptable

Laboratory rat Tech >17,000 Practically nontoxic

Farm Chemicals 

Handbook Unknown

THIRAM

Laboratory rat 99.0

1800 (F)

3700 (M)

2600 (M & F)

Slightly toxic 00153548

Thouin, 1985 Acceptable

ZIRAM

Laboratory rat 98.5 320 Moderately toxic

41340401

Liggett & Allan, 

1989

Acceptable

Table A-14. Acute Inhalation Toxicity to Mammals

Species % ai 4-hr LC50

(mg ai/L)

Toxicity 

Category

MRID

Author, Year

Study 

Classification

FERBAM

Laboratory rat 91.8 0.40 Toxicity Category 

II

41508101

Hardy & Jackson, 

1988

Acceptable

THIRAM

Laboratory rat Tech >0.1 Not determined 00152556

Debets, 1985 Acceptable

Laboratory rat Tech 2.60 < LC50 < 5.04 Not determined

40216501

Maedgen & Lain, 

1987

Acceptable

ZIRAM

Laboratory rat 98.5 0.06 (F)

0.08 (M)

Toxicity Category 

II

41442001

Jackson & Hardy, 

1989

Acceptable
Page 59 of 60

Table A-15. 2-Generation Reproductive Toxicity to Mammals 

Species % ai NOAEC / LOAEC

(mg ai/kg-bw)

Most Sensitive 

Endpoint

MRID No.

Author, Year

Study 

Classification

FERBAM

No data available

THIRAM

Laboratory rat 97.5 1.5 / 2.9 (M)

2.3 / 4.6 (F)

F0: Mean maternal 

body weight & 

food consumption, 

male food 

consumption

42095901

York, 1991 Acceptable

Laboratory rat 100 1.4 / 4.2 (M)

1.6 / 4.7 (F)

F0 & F1: Body 

weight

45441203

Turck, 1997 Acceptable

ZIRAM

Laboratory rat 97.8 14.8 / 37.5

F0 & F1: Body 

weight, body 

weight gain, food 

consumption

43935801

Nemec, 1996 Acceptable

2.3. Terrestrial Invertebrate Toxicity

Table A-16. Acute Contact Toxicity to Honey Bees

Species % ai 48-hr LD50

(μg ai/bee)

Toxicity 

Category

MRID

Author, Year

Study 

Classification

FERBAM

Honey bee (Apis 

Mellifera)

Fermate 

form. >12.09 Practically nontoxic

00036935

Atkins & Anderson, 

1967

Acceptable

THIRAM

Honey bee Tech 73.72 Practically nontoxic

00036935

Atkins et al., 1975 Acceptable

ZIRAM

Honey bee Zerlate 

form. 46.65 Practically nontoxic

00036935

Atkins & Anderson, 

1967

Acceptable

Honey bee 98.5 >200 Practically nontoxic

41667901

Cole, 1989 Acceptable

2.4. Terrestrial Plant Toxicity

No terrestrial plant toxicity data is available for ferbam or thiram. Data for ziram, another 

dimethyldithiocarbamate fungicide that degrades to thiram, are provided here.
Page 60 of 60

Table A-17. Tier I Seedling Emergence - Ziram (MRID 46893101; Porch & Krueger, 2006; Acceptable)

Species

Seedling Height Seedling Dry Weight Emergence

NOAEC

(lbs ai/A)

IC25

(lbs ai/A)

NOAEC

(lbs ai/A)

IC25

(lbs ai/A)

NOAEC

(lbs ai/A)

IC25

(lbs ai/A)

Monocots

Corn (Zea mays) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Onion (Allium cepa) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Ryegrass (Lolium perenne) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Wheat (Triticum aestivum) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Dicots

Cabbage (Brassica oleracea) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Lettuce (Lactuca sativa) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Radish (Raphanus sativus) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Soybean (Glycine max) <6.0 1 >6.0 6.0 >6.0 6.0 >6.0

Tomato (Solanum lycopersicum) 6.0 >6.0 6.0 >6.0 6.0 >6.0

Turnip (Brassica rapa) 6.0 >6.0 6.0 >6.0 6.0 >6.0

1 Decrease in height of 16%; not statistically significant but considered biologically significant.

Table A-18. Tier I Vegetative Vigor - Ziram (MRID 46893102; Porch & Krueger, 2006; Acceptable)

Species

Plant Height Dry Weight Survival

NOAEC

(lbs ai/A)

IC25

(lbs ai/A)

NOAEC

(lbs ai/A)

IC25

(lbs ai/A)

NOAEC

(lbs ai/A)

IC25

(lbs ai/A)

Monocots

Corn (Zea mays) 6.1 >6.1 6.1 >6.1 6.1 >6.1

Onion (Allium cepa) 6.1 >6.1 6.1 >6.1 6.1 >6.1

Ryegrass (Lolium perenne) 6.1 >6.1 <6.1 2 >6.1 6.1 >6.1

Wheat (Triticum aestivum) 6.1 >6.1 6.1 >6.1 6.1 >6.1

Dicots

Cabbage (Brassica oleracea) 6.1 >6.1 6.1 >6.1 6.1 >6.1

Lettuce (Lactuca sativa) 6.1 >6.1 6.1 >6.1 6.1 >6.1

Radish (Raphanus sativus) 1 6.1 >6.1 6.1 >6.1 6.1 >6.1

Soybean (Glycine max) 6.1 >6.1 6.1 >6.1 6.1 >6.1

Tomato (Solanum lycopersicum) 6.1 >6.1 <6.1 3 >6.1 6.1 >6.1

Turnip (Brassica rapa) 6.1 >6.1 6.1 >6.1 6.1 >6.1

1 A Tier II test was conducted for radish because 2 plants died in Tier I. No effects were seen in the Tier II test up to 6.1 lbs ai/A. 2 Decrease in dry weight of 13%; not statistically significant but considered biologically significant.

3 Decrease in dry weight of 12%; statistically significant.