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OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

August 4, 2015

PC Code: 034805

MEMORANDUM DP Barcode: 427965

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

Ecological Risk, Endangered Species, and Human Health Drinking Water 

Exposure Assessments for Ziram

FROM: Elyssa Arnold, Biologist

Ron Parker, Senior Environmental Engineer

Environmental Risk Branch 2

Environmental Fate and Effects Division (7507P)

James Breithaupt, Agronomist

David Bays, Biologist

Risk Assessment and Science Support Branch

Antimicrobials Division (7510P)

REVIEWED Melissa Panger, Senior Science Advisor

BY: Jim 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)

Laura Parsons, Associate Branch Chief

Risk Assessment and Support Branch (RASSB)

Antimicrobials Division (7510P)

TO: Khue Nguyen, Chemical Review Manager

Kelly Ballard, Acting Team Leader

Neil Anderson, Branch Chief

Risk Management and Implementation Branch 1

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....................................................................... 7

4.1. Ecological Risk Assessment............................................................................................. 7

4.2. Drinking Water Exposure Assessments........................................................................... 8

4.3. Clean Water Act Programs............................................................................................... 9

5. Environmental Fate and Transport.......................................................................................... 9

5.1. Transformation Products................................................................................................ 12

6. Receptors............................................................................................................................... 15

6.1. Effects to Aquatic Organisms ........................................................................................ 15

6.2. Effects to Terrestrial Organisms .................................................................................... 16

6.3. Ecological Incidents....................................................................................................... 17

7. Exposure Pathways of Concern ............................................................................................ 18

8. Analysis Plan ........................................................................................................................ 18

8.1. Stressors of Concern....................................................................................................... 18

8.2. Measures of Exposure .................................................................................................... 19

8.3. Measures of Effect ......................................................................................................... 20

8.4. Endangered Species Assessments.................................................................................. 20

8.5. Endocrine Disruptor Screening Program ....................................................................... 21

9. Preliminary Identification of Data Gaps............................................................................... 21

9.1. Environmental Fate ........................................................................................................ 21

9.2. Effects............................................................................................................................. 22

10. References.......................................................................................................................... 31

10.1. Submitted Environmental Fate Studies ...................................................................... 32

10.2. Submitted Ecological Toxicity Studies ...................................................................... 35

Appendix A. SIP Modeling Results.............................................................................................. 38

Appendix B. STIR Modeling Results........................................................................................... 39

Appendix C. Summary of Ziram and Thiram Fate and Transport Data ....................................... 40

Appendix D. Ziram, Thiram, and Ferbam Ecotoxicity Data ........................................................ 44

Appendix E. Thiram – Preliminary Identification of Data Gaps.................................................. 53
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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 ziram (PC 034805). 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 ziram. This document also identifies additional 

studies that would be beneficial to the conduct of an ecological risk assessment. This problem 

formulation includes discussion of ziram degradation into thiram (PC 079801), which is more 

persistent than parent ziram. The problem formulation for thiram can be found under DP427810

(USEPA, 2015). 

The ziram Reregistration Eligibility Decision (RED) was completed in 2004. The RED 

concluded that there was risk of adverse effects to aquatic invertebrates, fish, birds, and 

mammals from exposure to ziram. With the exception of mammals, chronic risk could not be 

assessed due to a lack of toxicity data. Data submitted following the RED will be incorporated 

into the registration review risk assessment.

The following are the needed data and uncertainties for ziram. See the thiram problem 

formulation for a complete description of the data needs and uncertainties for the major 

degradate thiram (USEPA, 2015). Appendix E also contains the preliminary identification of 

data gaps from the thiram problem formulation. Assessment of acute exposure to ziram requires 

data on ziram; thiram data are not a sufficient substitute. Assessment of chronic exposure 

resulting from ziram uses may be assessed using toxicity data on either ziram or thiram.

Data Needs

• Environmental fate and transport data (wastewater treatment plant (WWTP) studies for 

antimicrobial uses)1,2

o WWTP biodegradation tests (835.3110, 835.3220, 835.3240, 835.3280, TGAI)2

o Modified Activated Sludge Respiration Test (OECD 209 or 850.3300, TGAI)

• Ecotoxicity data on ziram

o Aquatic plant studies

 1 These data were also required of sodium and potassium dimethyldithiocarbamate salts earlier in registration 

review. The data could potentially be bridged between any of these three compounds. 2 The results of the ASRI test will determine which of these four biodegradation tests is/are anticipated to be 

required. If the ASRI test EC50 is less than or equal to 20 mg/L, then either the (i)Biodegradation in Activated 

Sludge Study or (ii) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units or (iii) the Porous Pot 

Test is expected to be required. If the ASRI test EC50 is greater than 20 mg/L, then the registrant would likely be 

required to conduct either: (i) Ready Biodegradability or (ii) a) Biodegradation in Activated Sludge or b) Simulation 

Test – Aerobic Sewage Treatment: A. Activated Sludge Units or c) the Porous Pot Test. If the Ready 

Biodegradability study is conducted and passes, then no further testing would be expected to be required. If, 

however, the antimicrobial fails the Ready Biodegradability study, then the a) Biodegradation in Activated Sludge or 

b) Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge Units, or c) the Porous Pot study would likely 

be required.
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 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 studies3

 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

 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

 850.4100: Seedling emergence

 850.4150: Vegetative vigor

• Ecotoxicity Data on Degradate Thiram4

o Aquatic animal studies

 OCSPP 850.1350: Mysid chronic toxicity 

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

Other Major Uncertainties

For many of the agricultural uses of ziram, 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 acute endpoints for freshwater fish and freshwater and estuarine/marine invertebrates are 

lower or approximately equal to the chronic NOAEC values for those taxa (see Section 6.1 for 

details). These results are unusual, and the explanation is not clear based on the information 

available in the study reports. Additional information to clarify these inconsistencies in the 

aquatic toxicity data is requested.

2. Introduction

Ziram, Zinc-bis(dimethyldithiocarbamate), is a dimethyldithiocarbamate fungicide and 

antimicrobial registered for use on stone fruits, pome fruits, nut crops, vegetables, and 

commercially grown ornamentals. Dimethyldithiocarbamate fungicides are non-systemic and act

by concomitant inhibition of spore germination and mycelial growth through multi-site 

 3 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.

4 This list includes the subset of studies requested in the thiram problem formulation (USEPA, 2015) that are also 

important for the risk assessment of ziram. 
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interference of enzyme processes associated with respiration. Ziram is also used as an 

antimicrobial in industrial adhesives, caulking, and latex paint. Ferbam (PC Code: 034801), a 

related dithiocarbamate, and ziram have a common degradate – thiram. Thiram (PC Code: 

079801) is also a registered dithiocarbamate fungicide. Because ferbam degrades very quickly 

(much more quickly than ziram) to thiram, ferbam and thiram are being assessed together during 

registration review. Although ziram is being assessed separately, the ziram assessment will rely 

heavily on the ferbam/thiram PF and assessment during registration review (DP427810; USEPA, 

2015). 

There are four active Section 3 registrations for ziram in the United States. One is a technicalgrade manufacturing-use product (EPA Reg. No. 70506-179), two are water dispersible granule 

formulations for use as agricultural fungicides (45728-12 and 70506-173), and one is a technicalgrade antimicrobial product (45728-14). There are also three active special local needs labels for 

dormant application on blueberries, one in New Jersey and two in Michigan. There are no 

registered co-formulated products with ziram.

EFED evaluated the most recent ecological risk assessments for ziram 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. Recent risk assessments include 

the 2001 EFED RED Chapter (USEPA, 2001) and a 2008 endangered species assessment on the 

California Red-legged Frog (USEPA, 2008). In addition, EFED considered the latest Agency 

science policies and risk assessment methodologies. 

3. Use Characterization

Ziram used in agriculture is applied as a foliar spray via aerial and ground application methods. 

The two labeled Section 3 end-use products are Ziram Granuflo (EPA Reg. No. 45728-12) and 

Ziram 76DF Fungicide (EPA Reg. No. 70506-17), both are 76% a.i. water dispersible granule 

formulations. Ziram targets a variety of fungal diseases and is registered for use on almonds, 

apples, apricots, blueberries, cherries, Christmas tree plantations, conifers, grapes, nectarines, 

ornamentals, peaches, pears, pecans, and tomatoes. The single maximum application rate is 7.6 

lbs active ingredient per acre (a.i./A) on peaches and nectarines. Ziram can also be used as an 

antimicrobial in the formulation of latex paint, paper and paperboard, paper coatings, water 

reduced industrial materials, adhesives, industrial yarns and fabrics, and dried films. Ziram was 

previously registered for use as a rabbit repellent for outdoor foliar applications to ornamentals.

The primary agricultural uses for ziram are on almonds (20-35% of crop treated, 900,000 lbs 

a.i./yr), apples (15-20% of crop treated, 400,000 lbs a.i./yr), apricots (35-70% of crop treated, 

30,000 lbs a.i./yr), blueberries (30-40% of crop treated, 80,000 lbs a.i./yr), nectarines (25-35% of 

crop treated, 50,000 lbs a.i./yr), peaches (30-40% of crop treated, 200,000 lbs a.i./yr), and pears 

(20-35% of crop treated, 100,000 lbs a.i./yr) (USEPA, 2014). 

Table 1 lists the maximum use patterns for the labeled agricultural use sites. EFED will use 

application scenarios that result in maximum exposure scenarios for a given use for the risk 

assessment. 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:
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• 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 Ziram

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

Almond 6.1 24.3 NS NS NS NS Aerial &

ground spray

Apple 4.6 32.2 7 NS NS NS Aerial &

ground spray

Apricot 6.1 24.4 4 NS NS NS Aerial &

ground spray

Blueberry 3.0 15.2 NS NS NS NS Aerial &

ground spray

2.3 NS NS NS NS NS Ground spray

Cherry 4.6 18.4 4 NS NS NS Aerial &

ground spray

Christmas 

tree 

plantations

6.1 6.1 1 NS NS NS Aerial &

ground spray

Conifer 

plantations 

& nurseries

6.1 NS NS NS NS 3 Aerial &

ground spray

Grape 3 NS NS NS NS 7 Aerial &

ground spray 

3 21.3 NS NS NS 7 Ground spray

Nectarine 7.6 45.6 6 NS NS NS Aerial &

ground spray

Ornamentals 6.1 NS NS NS NS 3 Aerial &

ground spray

Peach 7.6 45.6 6 NS NS NS Aerial &

ground spray

Pear – East 

of the 

Rockies

4.6 32.2 7 NS NS NS Aerial &

ground spray

Pear – West 

of the 

Rockies

4.6 18.4 4 NS NS NS Aerial &

ground spray

Pecan 6.1 36.6 6 NS NS 21 Ground spray

Tomato 3 18.0 NS NS NS 7 Ground spray

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

A map of estimated annual use for ziram in 2012 is presented in Figure 1.
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Figure 1. Estimated Agricultural Use for Ziram (USGS, 2012)

4. Conclusions from Previous Risk Assessments

4.1. Ecological Risk Assessment 

Recent ecological risk assessments for ziram include the 2001 EFED RED chapter (DPs 276759, 

260984, 260985) (USEPA, 2001) and a 2008 endangered species assessment on the California 

Red-legged Frog (CRLF) (USEPA, 2008). The RED concluded that there was risk of adverse 

effects to aquatic invertebrates, fish, birds, and mammals from exposure to ziram. With the 

exception of mammals, chronic risk could not be assessed due to a lack of toxicity data. The 
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CRLF assessment concluded that registered uses of ziram were likely to adversely affect the 

CRLF based on both direct and indirect effects. Figure 2 and Table 2 summarize the potential 

risks identified in previous assessments and the supporting evidence.

Figure 2. Graphic Summary of Potential Risks of Current Uses

Table 2. Evidence of Risk to Taxonomic Groups from Ziram Uses

Predominant Evidence of Negligible Risk Predominant Evidence of Risk

None Mammals: Acute and chronic risk LOC exceedances for 

listed and non-listed species from a single application. 

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. 

Toxicity data not available for other aquatic plant 

species.

Birds: Acute risk LOC exceedances for listed species 

only. No chronic toxicity data available.

Terrestrial invertebrates: Ziram is practically non-toxic 

to adult honey bees on an acute contact exposure basis. 

No other toxicity data available. 

Terrestrial plants: No toxicity data available. Two 

incidents reported.

4.2. Drinking Water Exposure Assessments

The drinking water exposure assessment for ziram was updated in 2010 based on label changes 

resulting from the RED (USEPA, 2010). Maximum Tier 2 exposure estimates for the residues of 

concern in surface water were 312 μg/L (1-in-10-year peak), 61.4 μg/L (1-in-10-year annual 

mean), and 27.9 μg/L (mean 26-year) using the PRZM and EXAMS models. Residues of 
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concern included the degradate thiram. For ground water, screening level exposure estimates 

were 0.03 μg/L for both acute and chronic exposure using the SCI-GROW model.

4.3. Clean Water Act Programs

Ziram is not identified as a cause of impairment for any water bodies listed as impaired under 

section 303(d) of the Clean Water Act.

5 No Total Maximum Daily Load (TMDL) criteria have 

been developed for ziram.6 Aquatic life benchmarks have been established for ziram and are 

available at http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm. 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

Ziram (Zinc bis (dimethyldithiocarbamate)) is slightly to moderately persistent in the 

environment with exposure to the degradate thiram (tetramethylthiram disulfide) extending the 

duration of exposure. Generally ziram degrades rapidly via hydrolysis and photodegradation. 

Degradation is somewhat slower in aerobic soil and slower still in anaerobic soil and water. Halflives are generally from a few days to a few weeks in soil and water; field studies show some 

residues may persist for months after application. Thiram degrades by similar pathways as ziram,

but hydrolysis, aerobic metabolism, and anaerobic metabolism tend to be somewhat slower than 

for ziram.

Hydrolysis of ziram is pH dependent, with hydrolytic decomposition being faster at the lower pH

values. The calculated half-lives were 0.173, 17.7, and 151 hours (∼6 days) at pH’s 5, 7, and 9, 

respectively. Study periods for hydrolysis were ≤72 hours for the pH 5 and 7 buffered solutions, 

for the pH 9 buffered solution, the study period was 30 days. It is noted that the major product in 

the pH 9 solution is not a true degradation or decomposition product. 

In aqueous photolytic conditions, ziram degraded with a half-life of 8.7 hours, as opposed to the 

dark control that did not degrade substantially during the same study period (24 hours). 

In a soil photolysis study, ziram was applied at two treatment rates of approximately 15 and 3 

ppm to sandy loam soil samples that were incubated aerobically for up to 72 hours. Both 

irradiated treatment rates show similar degradation half-life of ziram at about 8-9 hours. In 

contrast, the dark controls had half-lives of about 16-24 hours. The soil was acidic, which may 

have promoted hydrolysis and confounded the results. It is acknowledged, however, that in 

water, photolysis is also important. This is an indication that on soils, it may be important too. 

The dark control showed much slower degradation rates than the exposed sample. 

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

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

_group_name=PESTICIDES
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In an aerobic sandy loam soil study, ziram dissipated with a half-life of 1.75 days. Samples were 

incubated for up to 60 days. EFED has some concerns regarding the results obtained from this 

study because it was also conducted on a soil at a lower pH (5.4). This pH may raise the rate of 

degradation of ziram by promoting hydrolysis. However, the major degradate observed in this 

study, 1,1-dimethylurea (10.5% at day 30) was not observed in the hydrolysis study, and the 

degradates observed in the hydrolysis study were not present in large quantities in this study. 

Therefore, hydrolysis is likely not affecting the rate in this study. In the study, seven minor 

degradates were detected (<10%) and CO2 accounted for 48.3% of the applied at 60 days.

In an anaerobic soil metabolism study, ziram was applied to an aerobic sandy loam soil and 

incubated for one day, after which approximately 1⁄3 of the radioactivity was undegraded parent. 

The samples were then flooded and submitted under a nitrogen atmosphere. It was found that 

under anaerobic conditions ziram degraded at a decreased speed, compared to the aerobic 

conditions. The half-life was 14.1 days under anaerobic conditions. Up to 10 minor degradates 

(at <10%) were detected. At the end of the 30 day anaerobic incubation, 35.2% of the applied 

was CO2.

Observed half-lives (0.17-42 hours) are generally fast under the expected use condition, 

generating major volatiles such as carbon disulfide (CS2), carbon dioxide (CO2), and carbon 

oxide sulfide or carbonyl sulfide (COS). Laboratory studies suggest that ziram hydrolyzed very 

rapidly and yielding CS2 (≥80% of applied ziram) at pH 5 and pH 7 but degraded (t1/2=151 

hours) moderately at pH 9. Nonvolatile metabolite thiram (13.8% of applied ziram) at pH 7 and 

DDC (≈67.0 % of applied ziram) at pH 9 were also formed during the hydrolysis experiments. 

Other major persistent degradation products (≥18%) of ziram were identified as DMF and 

DMTF in aqueous and soil photolysis studies. Degradation is somewhat slower in aerobic soil 

and slower still in anaerobic soil and water. Half-lives are generally from a few days to a few 

weeks in soil and water; field studies show some residues may persist for months after 

application.

Rapid degradative processes of parent ziram suggest that it would not persist in environment. 

However, in alkaline medium, ziram and its nonvolatile metabolites dimethyldithiocarbamic acid 

(DDC), N.N-dimethylformamide (DMF), and N.N-dimethylthioforamide (DMTF) are likely to 

be more persistent. The uncertainties related to the persistence of DDC, DMF, and DMTF could 

be a concern for the soils of arid and semiarid regions. 

Laboratory and field data suggest that ziram is not very mobile, and neither leaching nor 

volatility are expected to play an important role in the dissipation of ziram. The degree of 

adsorption of ziram in the studied soils was found not to be a function of the amount of organic 

matter (r2 = 0.31) rather than the amount of clay contents (r2 = 0.96) of the soils. Volatilization is 

not expected to be a major route of dissipation due to ziram’s low vapor pressure. The major 

degradates of ziram are volatiles, and are not expected to persist in soil or water. Therefore, 

subsurface mobility of ziram will be minimal. 

In terrestrial dissipation studies, ziram (Ziram 76DF®) dissipation appeared to be biphasic, with 

faster degradate initially following application, followed by a slower degradation until the end of 

the study. Required data for aquatic dissipation and bioaccumulation are not available for ziram, 

however, a rapid hydrolysis of ziram under a neutral pH suggests that ziram would not persist 

long enough in water to cause substantial bioaccumulation in aquatic species. 
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Table 3 summarizes the chemical and environmental fate properties of ziram. A detailed 

description of the available data can also be found in Appendix C. Details on the chemical 

properties and environmental fate parameters of the major degradate thiram can be found in the 

thiram problem formulation (USEPA, 2015).

Table 3. Chemical Properties and Environmental Fate Parameters of Ziram

Parameter Value Description Source

Selected Physical/Chemical Parameters

Molecular mass (molecular formula)

305.8 g/mol

(C6H12N2S4Zn)

NA (Calculated)

Vapor pressure (25°C) 0.018 mPa Low potential for 

volatilization PPDB

Aqueous solubility (20°C) 0.97 mg/L Soluble PPDB

Henry’s Law Constant (20°C) 5.6 x 10-8 Pa-m3

/mol

2.3 x 10-6 (dimensionless)

Low potential for 

volatilization (Calculated)

Log octanol-to-water partition 

coefficient (log KOW) 1.65 Moderately 

hydrophobic PPDB

Persistence

Hydrolysis half-life (25°C)

pH 5: 0.07 d

pH 7: 0.74 d

pH 9: 6.3 d

Rapid degradation MRID 43866701

Aqueous photolysis half-life (25°C) 0.43 d Rapid degradation MRID 44097701

Soil photolysis half-life (25°C) 0.3 d Rapid degradation MRID 43642501

Aerobic soil metabolism half-life 

(25°C) 3.5, 4.4, 4.9, 5.3 d Rapid degradation

MRIDs 43985801, 

46622302, 

47005202

Anaerobic soil metabolism half-life 

(25°C) 14.1 d NA MRID 44228402

Aerobic aquatic metabolism half-life

(water column) (25°C)

River 0.3 d (DT90 = 1.0 d)

Pond 0.2 d (DT90 = 0.7 d)

Rapid degradation in 

water column; ziram 

not detected in 

sediment.

MRID 46045903

Anaerobic aquatic metabolism half-life 

(25°C) NA NA NA

Mobility

Freundlich soil-water partition 

coefficients (KF); organic carbonnormalized Freundlich coefficients 

(KFOC)

Kd: 5.7 ml/g (2.9-68.1)

Koc: 314-3732 ml/g

Slightly to moderately 

mobile MRID 43873501

NA: Not Available
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5.1. Transformation Products

The main decomposition products of hydrolysis observed for ziram are volatile: CS2 (maximum 

of 96.8% of the applied after 1 hour in the pH 5 solution, 81.6% at 72 hours in the pH 7 solution, 

and 16.43% at 21 hours in the pH 9 solution) and COS (maximum of 18.6% of the applied 30 

days after treatment in the pH 9 solution). One non-volatile product is DDC (appeared to be a 

transient component, it was 11.6% at 0.117 hour in the pH 5, but decreased substantially by 1 

hour post-treatment, at 0.15%; it was also present in the pH 9 solution at a maximum of 66.7% at 

30 days post-treatment). DDC is not a true degradation product of ziram, but an analogous salt.

Thiram, another major, non-volatile hydrolysis product is often formed rapidly and is of 

toxicological concern. Thiram was found to be up to 13.78% of the applied at 4 hours posttreatment in the pH 7 solution. It had decreased to 11.0% by 72 hours, the final test interval.

In an aqueous photolysis study, about 15 degradates were observed during the study period. The 

major degradates (>10%) after 24 hours of irradiation were DMF (N,N-dimethylformamide: 

23.7% of the applied), and DMTF (N,N-methylthioformamide: 18.1% of the applied). The 

patterns of formation/decline of these degradates did not reveal whether they would persist or 

degrade after 24 hours under the described experimental conditions.

In the soil photolysis study, degradate profiles are similar (up to 10 degradates). The only 

degradate at >10% was thiram, at 27.3% in the 24 hour study. However, the pattern of 

formation/decline of thiram suggests that the level was declining toward 10%. Also, the 

persistence of thiram oxide was considered to be an artifact of the test solvent acetonitrile 

(CH3CN).

In the aerobic sandy loam soil study described above, the major degradate observed was 1,1-

dimethylurea (10.5% at day 30). Seven minor degradates were also detected (<10%) and CO2

accounted for 48.3% of the applied at 60 days.

Ziram’s major degradates are detailed in Table 4.
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Table 4. Ziram and Its Environmental Transformation Products

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR 

(day) A

Final %AR 

(study length)

PARENT

Ziram Zinc bis 

(dimethyldithiocarbamate)

CAS No.: 137-30-4

C9H18FeN3S6

Formula: C6H12N2S4Zn

MW: 305.813 g/mol

MAJOR TRANSFORMATION PRODUCTS

Thiram Tetramethylthiram disulfide

CAS No.: 137-26-8

Formula: C6H12N2S4

MW: 240.43 g/mol

Hydrolysis 43866701 13.8% (4 hrs)

11.0% (72 hrs) 72 hours

Soil photolysis 44228041 Sandy Loam

27.3% (24 hrs) 24 hours

Aerobic soil 46622302 49.4% (1 hr)

0.3% (28 days) 28 days

Anaerobic soil 44228402 1.03% (0 days)

0.41% (30 days) 30 days

Terrestrial Field 

Dissipation

44548301

44548302

46545601

Sand (NC)

Sandy Loam 

(CA)

Aerobic aquatic 46045903 47.5% (6 hrs)

2.3% (7 days) 101 days

DDC Dimethyldithiocarbamic acid Hydrolysis pH 5 43866701 11.6% (0.12 hrs)

0.15 % (1 hr) 72 hours

DMTF N,N-methylthioformamide

Soil Photolysis 44228401 3.06% (16 hrs)

2.99% (24 hrs) 24 hours

Aqueous Photolysis 44097701 18.1% (18 hrs) 24 hours
Page 14 of 57

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type MRID Maximum %AR 

(day) A

Final %AR 

(study length)

DMF N,N-dimethylformamide

Soil Photolysis 44228401 4.51% (24 hrs) 24 hours

Aqueous Photolysis 44097701 23.7% (24 hrs) 24 hours

COS Carbonyl sulfide Hydrolysis pH 9 43806701 18.6% (30 days) 30 days

1,1-dimethylurea 1,1-dimethylurea Aerobic Soil 43985801 10.5% (30 days)

5.25% (60 days) 60 days

CS2 Carbon disulfide Hydrolysis pH 5

Hydrolysis pH 7 43866701 96.8% (1 hr)86.6% (72 hrs) 72 hours

CO2 Carbon dioxide Aerobic Soil 43985801 48.3% (60 days) 60 days

Aerobic Aquatic 46045903 82.3% (101 days) 101 days
15

6. Receptors

Table 5 and Table 6 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 ziram. A complete list of the ecotoxicity data available for ziram, 

major degradate thiram, and the related dithiocarbamate ferbam can be found in Appendix D.

Discussion of available thiram toxicity data and tables of the most sensitive endpoints for thiram 

can be found in the thiram problem formulation (USEPA, 2015).

6.1. Effects to Aquatic Organisms

Ziram is 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 a NOAEC of approximately 0.02 mg a.i./L. The 

fathead minnow LC50 value is an order of magnitude lower than the NOAEC value from the full 

life cycle study. The daphnid and mysid LC50 values are both very close to the chronic NOAEC 

values for those species. These results are unusual, and the explanation is not clear based on the 

information available in the study reports and DERs. Probit slopes for the daphnid and mysid 

acute data were 2.0 and 2.3, respectively. No slope is available for the fathead minnow study. 

The acute studies in question were all performed in the early 1990s, while the chronic studies 

were performed between 2006 and 2008. Differences in analytical methods between these time 

periods may provide some explanation. Additional information to clarify these inconsistencies in 

the aquatic toxicity data is requested.

Effects on biomass were observed on tested vascular and non-vascular aquatic plant species.

Table 5. Summary of Most Sensitive Toxicity Endpoints for Aquatic Organisms Exposed to Ziram

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

(99.0%)

Fathead minnow 

(Pimephales 

promelas)

96-hr LC50 = 0.008

(Very highly toxic)

05003523

Supplemental

Chronic 

(Early-life 

Stage)

TGAI

(98.2%) Fathead minnow

33-d NOAEC = 0.101

33-d LOAEC = 0.195

(Post-hatch survival)

46893104

Acceptable

Chronic 

(Full Life 

Cycle)

TGAI

(98.2%) Fathead minnow

275-d NOAEC 0.024

275-d LOAEC = 0.051

(F0 length and weight)

47435501

Supplemental

Estuarine/

marine fish

Acute TGAI

(98.9%)

Sheepshead Minnow 

(Cyprinodon 

variegatus)

96-hr LC50 = 0.84

(Highly toxic)

43781601

Acceptable

Chronic TGAI

(98.2%) Sheepshead Minnow

34-d NOAEC = 0.027

34-d LOAEC = 0.058

(Larval length and dry weight)

46856401

Acceptable
16

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

(98.9%)

Water Flea

(Daphnia magna)

48-hr EC50 = 0.048

(Very highly toxic)

42386305

Acceptable

Chronic TGAI

(98.2%) Water Flea

21-d NOAEC = 0.039

21-d LOAEC = 0.078

(Length)

46823301

Acceptable

Estuarine/

marine 

invertebrates

Acute 

(Shell 

Deposition)

TGAI

(98.0%)

Eastern Oyster 

(Crassostrea 

virginica)

96-hr EC50 = 0.077

(Very highly toxic)

43781602

Acceptable

Acute TGAI

(98.0%)

Mysid Shrimp 

(Mysidopsis bahia)

96-hr LC50 = 0.014

(Very highly toxic)

43781603

Acceptable

Chronic TGAI

(98.2%) Mysid Shrimp

27-d NOAEC = 0.016

27-d LOAEC = 0.027

(Reproduction and dry weight)

46893103

Supplemental

Aquatic Plants

Aquatic 

plants and 

algae

Vascular TGAI

(98.2%)

Duckweed

(Lemna gibba)

7-d NOAEC = 0.035

7-d EC50 = 0.37

(Biomass)

46823302

Acceptable

NonvascularTGAI

(98.0%)

Green Algae 

(Pseudokirchneriella 

subcapitata)

120-hr NOAEC < 0.038

120-hr EC50 = 0.067

(Biomass)

43833901

Acceptable

6.2. Effects to Terrestrial Organisms

Ziram is 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 ziram’s repellency properties for rabbits also apply to birds. A 

decrease in body weight and food consumption was observed for the first week following dosing 

in the avian acute oral study on the bobwhite quail (MRID 41725701). Decreases in body weight 

gain were observed in dietary studies on both the bobwhite quail (at 2600 mg/kg-diet) and 

mallard duck (at 650 mg/kg-diet, the lowest concentration tested) (MRIDs 42386301, 

42386302). These effects were more pronounced and observed at lower doses for the mallard 

duck than for the bobwhite quail. Effects on body weight and food consumption were not 

observed in the avian reproduction study on the mallard duck, which was conducted at 

concentrations up to 64 mg/kg-diet (MRID 47286501). No acceptable avian reproduction study 

is available for the bobwhite quail.

Ziram is practically non-toxic to honey bees on an acute contact exposure basis. No other 

toxicity data are available for terrestrial invertebrates. 

Minimal effects were observed in Tier I terrestrial plant toxicity tests, including a 16% reduction 

in soybean height in the seedling emergence study and 12 and 13% reductions in tomato and 

ryegrass dry weight, respectively, in the vegetative vigor study.
17

Table 6. Summary of Most Sensitive Toxicity Endpoints for Terrestrial Organisms Exposed to 

Ziram

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

(98.5%)

Bobwhite quail

(Colinus virginianus)

LD50 = 97 mg/kg-bw

(Moderately toxic)

41725701

Acceptable

Sub-acute 

dietary

TGAI

(98.5%)

Mallard duck (Anas 

platyrhynchus)

LC50 = 5156 mg/kg-diet

(Practically non-toxic)

42386302

Acceptable

Chronic TGAI

(98.8%) Mallard duck

NOAEC = 29 mg/kg-diet

LOAEC = 64 mg/kg-diet

Eggs set, eggs set/eggs laid, 

embryo viability, 

hatchability,14-day survivors/ 

eggs set

47286501

Acceptable

Mammals1

Acute Oral TGAI

(98.5%)

Laboratory rat

(Rattus norvegicus)

LD50 = 320 mg/kg-bw

(Moderately toxic)

41340401

Acceptable

Acute 

Inhalation

TGAI

(98.5%)

LC50 = 0.06 mg/L

(Toxicity Category II)

41442001

Acceptable

Chronic (2-

generation 

reproduction)

TGAI

(97.8%)

NOAEC=14.8 mg/kg-bw/day

LOAEC=37.5 mg/kg-bw/day

(F0 & F1 body weight, body 

weight gain, food 

consumption)

43935801

Acceptable

Terrestrial 

Invertebrates

Acute 

contact

TGAI

(98.5%)

Honey bee

(Apis mellifera)

48-hr LD50 > 200 μg/bee

(Practically non-toxic)

41667901

Acceptable

Terrestrial 

Plants

Seedling 

Emergence

TEP

(76.6%)

Monocot: None

NOAEC > 6.0 lb/A

IC25 > 6.0 lb/A

(No effects) 46893101

Acceptable

Dicot: Soybean

NOAEC < 6.0 lb/A

IC25 > 6.0 lb/A

(Height)

Vegetative 

Vigor

TEP

(76.6%)

Monocot: Ryegrass

NOAEC < 6.1 lb/A

IC25 > 6.1 lb/A

(Dry weight) 46893102

Acceptable

Dicot: Tomato

NOAEC < 6.1 lb/A

IC25 > 6.1 lb/A

(Dry weight) 1 Mammalian toxicity endpoints are 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 
18

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 terrestrial plant incident in California attributed to ziram with “possible” 

certainty. Incident I013563-012 occurred in March 1999 when a registered agricultural use of 

ziram was applied to apricots, along with the fungicide fenbuconazole. Forty acres of apricots 

were damaged, resulting in a loss of yield. 

As of March 30, 2015, AIMS identified no ecological incidents involving ziram. 

Registrants reported one aggregate plant incident with ziram in 2002. Unless additional 

information on this aggregated incident becomes available, it will be assumed to be 

representative of registered uses of ziram in the risk assessment.

7. Exposure Pathways of Concern

The environmental fate properties and use patterns of ziram indicate that direct spray, spray drift, 

and runoff represent potential transport mechanisms to aquatic and terrestrial organisms.

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

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

results indicated that drinking water alone is not a potential exposure pathway of concern for 

birds or mammals (see Appendix A). STIR results showed that droplet inhalation may be an 

exposure pathway of concern for both birds and mammals, but exposure via vapor inhalation is 

not likely to be significant (see Appendix B). 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

Ziram and its major degradate thiram, which is also a registered active ingredient (PC 079801), 

are the stressors of concern for both the ecological and drinking water risk assessments for 

registration review. Thiram is the only major degradate of ziram expected to maintain the 

toxicity of the parent compound. The degradates 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.7 This exposure pathway for CS2 will be considered in the 

risk assessment.

 7 See http://www.epa.gov/ttnatw01/hlthef/carbondi.html#ref1 and 
19

8.2. Measures of Exposure 

Conventional Uses

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 

http://www.epa.gov/pesticides/science/models_db.htm. Acute exposure will be assessed with 

modeling inputs based on parent ziram properties (acute exposure estimates to thiram are 

substantially less) and chronic exposure will be assessed by assignment of the fate properties of

thiram to the total residues of concern. This methodology provides a protective assessment of 

chronic exposure for chronic risk.

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. Ziram’s use as a rabbit repellent and thiram’s use as a rabbit, rodent, and 

deer repellent will be considered when characterizing potential exposure to terrestrial animals.

See Section 6.2 of the thiram problem formulation (USEPA, 2015) for details on the available 

toxicity data addressing the repellent properties of thiram to avian species.

In addition, E-FAST may be used to assess industrial uses of ziram as an antimicrobial. E-FAST 

is described in detail at http://www.epa.gov/oppt/exposure/pubs/efast.htm.

Ziram has not be detected in either surface or groundwater in the USGS NAWQA or other 

monitoring programs. Rapid hydrolysis makes detection in water unlikely.

Antimicrobial Uses

The only label for with antimicrobial uses of ziram is Reg. No. 45728-14, which contains uses in 

latex paint (0.98-2.94 % ai w/w), paper and paperboard (surface treatment at 0.49 % ai w/w), 

paper coatings at 0.098 % ai w/w), adhesives (for packaging at 0.18-0.49 % ai w/w), industrial 

yarns and fabrics (1.23 % ai w/w), dried films (e.g. caulk and grout at 0.18-0.49 % ai w/w), and 

wall board (for short-term spoilage protection at 0.39-0.49 % ai w/w). Based on the summary of 

registered uses of Ziram from Reg. No. 45728-14 and the chemical, physical, and environmental 

fate properties in Table 3, the Agency has developed conceptual model diagrams for exposure of 

ecological organisms to ziram. Ziram is related to the dimethyl dithiocarbamate compounds 

thiram and ferbam; it generally degrades rapidly, is associated with water in the presence of 

sediment, and does not significantly move from water or soil into air by volatility. In a WWTP, 

the primary route of dissipation is expected to be hydrolysis, which primarily forms 

dimethylamine (DMA) and carbon disulfide (CS2). DMA is considered to be an inert material for 

non-food uses8 and CS2 is volatile and moves from water into air. 

Chemicals that are released down-the-drain can typically take from a few to several hours to 

reach wastewater treatment plant intakes following their discharge and from several hours to 

 http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=474&tid=84 for additional information on carbon disulfide. 8 http://iaspub.epa.gov/apex/pesticides/f?p=INERTFINDER:3:0::NO::P3_ID:7544
20

roughly a day following their discharge down-the-drain to subsequently be discharged from 

wastewater treatment plants to surface water. Data on WWTP dissipation have not been 

submitted for ziram, however, the primary routes of dissipation are expected to be partitioning to 

water with some degradation and subsequent outflow in effluent. 

The Agency has created conceptual models for potential routes of environmental exposure which 

are included in “Conceptual Models for Environmental Exposure Pathways of Antimicrobial 

Pesticides,” (EPA-HQ-OPP-2014-0638-0002), found in the docket at www.regulations.gov, 

EPA-HQ-OPP-2014-0638. The Agency does not consider the wall board or treated adhesives in 

packaging uses to create environmental exposure because the treated materials are not 

anticipated to come into contact with water. 

Use sites and corresponding figures of conceptual model diagrams are as follows:

• Industrial yarns and fabrics (slide 16)

• Dried films (e.g., caulks, sealants, slide 18)

• Paint preservation (slides 24 and 25)

• Paper manufacturing (slide 26)

8.3. Measures of Effect 

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

quotients. Toxicity data for the major degradate thiram will also be used for chronic risk 

quotients when the endpoints are more sensitive than those for ziram. Thiram toxicity data can be 

found in Appendix D and in the thiram problem formulation for registration review (USEPA, 

2015). 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 

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 ziram in 

connection with the development of its final registration review decision for ziram.
21

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 ziram 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 ziram 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 ziram as part of completing this registration review.

8.5. Endocrine Disruptor Screening Program

Ziram was not included in the first group of 67 chemicals issued an order to conduct Tier 1 

EDSP testing. Ziram is 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

Table 7 identifies environmental fate studies by MRID that offer data for each guideline 

requirement, as well as study classifications and whether or not further data are needed in order 

to support risk assessment.

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

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

methods are fully adequate to assess residues from a ziram treated field. 
22

Table 7. Submitted Environmental Fate Data for Ziram

OCSPP 

Guideline Data Requirement Submitted Studies (MRID) Study Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

835.2120 Hydrolysis 43866701 Acceptable No

835.2240 Aqueous photolysis 44097701 Acceptable No

835.2410 Soil photolysis 43642501 Acceptable No

835.4100 Aerobic soil metabolism 43985801

46622302

Acceptable

Supplemental No

835.4200 Anaerobic soil metabolism 44228402 Acceptable No

835.4300 Aerobic aquatic metabolism 46045903 In Review

Only if study in 

review is found to 

be unacceptable.

835.4400 Anaerobic aquatic 

metabolism None NA No

835.1230

835.1240

Adsorption/ desorption and 

leaching 43873501 Acceptable No

835.6100 Terrestrial field dissipation

44548301

44548302

46545601

Supplemental

Supplemental

Acceptable

No

850.1730 Fish bioconcentration None NA No

850.6100 Analytical method in soil None NA No Analytical method in water None NA

9.2. Effects

Table 8 and Table 9 identify ecological effects studies by MRID that offer data for each 

guideline requirement, as well as study classifications and whether or not further data are needed 

in order to support risk assessment. Rationale for the additional non-guideline data requested is 

presented below the tables.

Table 8. Submitted Aquatic Ecological Effects Data for Ziram

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

42386305 Acceptable

No None1

47405701 Acceptable

850.1025

850.1035

850.1045

850.1055

Saltwater 

invertebrate

acute toxicity

40228401 Supplemental

No None1 43781602 Acceptable

43781603 Acceptable

47405702 Acceptable

850.1075 Freshwater fish acute 

toxicity

TN 1021 Supplemental

No None1 00138214 Supplemental

00138215 Supplemental
23

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

05003523 Supplemental

42386303 Acceptable

42386304 Acceptable

47307901 Acceptable

850.1075 Saltwater fish acute 

toxicity

40228401 Supplemental No None

43781601 Acceptable

850.1300

Freshwater 

invertebrate

life cycle

46823301 Acceptable No None1

850.1350

Saltwater 

invertebrates

life cycle

46893103 Supplemental No None1

850.1400 Freshwater fish

early-life stage 46893104 Acceptable No None1

850.1400 Saltwater fish

early-life stage 46856401 Acceptable No None

850.1500 Fish life cycle 47435501 Supplemental No None1

850.1735

Whole sediment 10-d 

freshwater 

invertebrate

None NA No

None. Ziram is not 

expected to accumulate in 

sediment.

850.1740

Whole sediment 10-d 

estuarine/marine 

invertebrate

None NA No

None. Ziram is not 

expected to accumulate in 

sediment.

850.4400

Aquatic plant 

Toxicity Test using 

Lemna spp.

46823302 Acceptable No None

850.4500 Algal toxicity 43833901 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.

850.4550 Cyanobacteria None NA Yes

A cyanobacteria will 

reduce uncertainty in the 

assessment of risk to nonvascular plants. 1 The acute endpoints for freshwater fish and freshwater and estuarine/marine invertebrates are lower or 

approximately equal to the chronic NOAEC values for those taxa. Additional information to clarify these

inconsistencies in the aquatic toxicity data is requested.
24

Table 9. Submitted Terrestrial Ecological Effects Data for Ziram

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 41725701 Acceptable Yes

A study with a passerine 

species will reduce 

uncertainty in the 

assessment of risk to 

birds.

850.2200 Avian dietary 

toxicity

42386301 Acceptable

No None

42386302 Acceptable

850.2300 Avian reproduction 47286501 Acceptable No

None. While no 

acceptable data are 

available for bobwhite 

quail, studies of other 

dithiocarbamates indicate 

that the mallard is more 

sensitive.

Nonguideline Avian inhalation None NA No

While STIR indicated a 

potential risk to birds 

from droplet inhalation, 

this exposure pathway is 

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

41667901 Acceptable

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.

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.
25

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 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 46893101 Acceptable Yes

Studies are needed at the 

maximum application rate 

of 7.6 lb a.i./A. The 

previously submitted 

studies were conducted at 

6.1 lb a.i./A. Effects seen 

in those studies and 

incident reports indicate 

that risk to terrestrial 

plants may be a concern.

850.4150 Vegetative Vigor 46893102 Acceptable Yes

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 

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-risk-
26

assessment-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 

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 
27

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 

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. 
28

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 

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 
29

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 

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 
30

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/pollinatorprotection/pollinator-risk-assessment-guidance.

Practical Utility of the Data
31

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 

United States Environmental Protection Agency (USEPA). 2001. Federoff, N.E., J. Melendez, 

and F. Khan. EFED RED Chapter for Ziram. DP Barcodes 276759, 260984, 260985. 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. Oct. 23, 2001.

USEPA. 2004. 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/

USEPA. 2008. Woodard, V. and M. Barrett. Risk of Ziram Use to Federally Threatened 

California Red-legged Frog (Rana aurora draytonii). U.S. Environmental Protection 

Agency, Office of Pesticide Programs, Environmental Fate and Effects Division. Oct. 

16, 2008.

USEPA. 2010. Barrett, M. Ziram Drinking Water Assessment for Updated Use Patterns. DP 

Barcode 323411. U.S. Environmental Protection Agency, Office of Prevention, 

Pesticides, and Toxic Substances, Environmental Fate and Effects Division.

Memorandum to the Health Effects Division. Feb. 18, 2010.

USEPA. 2014. Screening Level Usage Analysis (SLUA) for Ziram (034805). U.S. 

Environmental Protection Agency, Office of Pesticide Programs, Biological and 

Economic Analysis Division. Jun. 20, 2014.
32

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.

U.S. EPA, Office of Pesticide Programs, Antimicrobial Division, Risk Assessment and Science 

Support Branch. August 4, 2014. Conceptual Models for Environmental Exposure 

Pathways of Antimicrobial Pesticides. EPA-HQ-OPP-2014-0638. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2014-0638-0002

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 Ferbam and Thiram. DP Barcode 427810, 

427924. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution 

Prevention, Environmental Fate and Effects Division. Memorandum to the Pesticide Reevaluation Division.

10.1. Submitted Environmental Fate Studies

034805 Ziram Fate Chemistry Bibliography Revised 31 July 2014

161-1 Hydrolysis

MRID Citation Reference

142855 2005678 Lemal, R.; Boel, C.; Debondues, M. (1984) Ziram: Rate of Hydrolysis as a Function of pH. 

Unpublished study prepared by UCB, Drogenbos Laboratory. 6 p. 

154985 Open Lit

DER not 

located

Korotkova, O. (1976) Razlozhenie fungitsidov--proizvodnykh ditio- karbaminovoy kisloty (obzor 

literatury) [Decomposition of such fungicides as derivatives of dithiocarbamic acid (literature review)]. Khim. Sel'sk. Khoz. 12(11):869-874, 1974. Abstracted in Pest. Abs. 76-0215. 

40497301 2005677 Daly, D.; Cranor, W. (1987) Determination of Hydrolysis Rate with ?Carbon 14|-Ziram: Final Report 

#33363. Unpublished study pre- pared by Analytical Bio-Chemistry Laboratories, Inc. 573 p. 

43866701 2005689 Kim-Kang, H. (1995) Hydrolysis of (carbon 14)-Ziram in Water at pH 5, 6, and 9: Lab Project Number: 

XBL 94071: PRT00213: IDC433102. Unpublished study prepared by Xenobiotic Labs, Inc. and NPC 

Inc. 272 p. 

161-2 Photodegradation-water

MRID Citation Reference

153198 2005676 Carpenter, M. (1985) Determination of Photodegradation of Ziram in Aqueous Solution: Report 

33369. Unpublished study prepared by Analytical Bio-Chemistry Labs., Inc. 53 p. 

154985 Open Lit Korotkova, O. (1976) Razlozhenie fungitsidov--proizvodnykh ditio- karbaminovoy kisloty (obzor 

literatury) [Decomposition of such fungicides as derivatives of dithiocarbamic acid (literature review)]. Khim. Sel'sk. Khoz. 12(11):869-874, 1974. Abstracted in Pest. Abs. 76-0215. 

44097701 2005690 Kim-Kang, H. (1996) Aqueous Photolysis of (carbon 14)-Ziram: Lab Project Number: XBL94073: 

RPT00223: IDC 433102. Unpublished study prepared by XenoBiotic Labs, Inc. 245 p. 

161-3 Photodegradation-soil
33

MRID Citation Reference

153199 2005675 Carpenter, M. (1985) Determination of Photodegradation of Ziram on the Surface of Soil: Report 

33370. Unpublished study prepared by Analytical Bio-Chemistry Labs., 60 p. 

154985 Open Lit Korotkova, O. (1976) Razlozhenie fungitsidov--proizvodnykh ditio- karbaminovoy kisloty (obzor 

literatury) [Decomposition of such fungicides as derivatives of dithiocarbamic acid (literature review)]. Khim. Sel'sk. Khoz. 12(11):869-874, 1974. Abstracted in Pest. Abs. 76-0215. 

44228401 2005691 Reynolds, J. (1997) Photolysis of (carbon 14) Ziram on Soil: (Final Report): Lab Project Number: 

96001: RPT00296: XBL 96001. Unpublished study prepared by XenoBiotic Laboratories, Inc. 179 p. 

162-1 Aerobic soil metabolism

MRID Citation Reference

40061601 2005674 Cranor, W. (1987) Aerobic Soil Metabolism Study with [Carbon 14]- Ziram: Final Report #33366. 

Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 85 p. 

43985801 2005692 Kim-Kang, H. (1996) Aerobic Soil Metabolism of (carbon 14)- Ziram: Lab Project Number: XBL 

94072: RPT00225. Unpublished study prepared by XenoBiotic Labs, Inc. 180 p. 

47005202 2084558 pg. 

5 referenced

Reibach, P. (2006) (Carbon 14)-Ziram Fungicide Soil Metabolism. Project Number: KP/2006/44. 

Unpublished study prepared by Cerexagri, Inc. 11 p.

46622302 20050483 Mamouni, A. and Piccirillo, V. (2001) Degradation Rate of (Carbon 14)-Ziram in Three Soils 

Incubated Under Aerobic Conditions. Project Number: 785744. Unpublished study prepared by 

RCC Umweltchemie Ag. 90 p.

162-2 Anaerobic soil metabolism

MRID Citation Reference

40061602 2005673 Cranor, W. (1987) Anaerobic Soil Metabolism Study with [Carbon 14]- Ziram: Final Report #33367. 

Unpublished study prepared by Analytical Bio-Chemistry Laboratories, Inc. 70 p. 

44228402 2005693 Reynolds, J.; Smalley, J. (1997) Anaerobic Soil Metabolism of (carbon 14) Ziram: (Final Report): 

Lab Project Number: XBL96002: RPT00297: XBL 96002. Unpublished study prepared by 

XenoBiotic Laboratories, Inc. 111 p. 

Aerobic Aquatic Metabolism

MRID Citation Reference

46045903 DER not 

located

Volkl, S. (2001) (Carbon 14)-Ziram: Route and Rate of Degradation in Aerobic Aquatic Systems. 

Project Number: 744693. Unpublished study prepared by RCC Umweltchemie Ag. 109 p.

163-1 Leach/adsorption/desorption

MRID Citation Reference

151488 2005670

2005671

Warren, J. (1985) Leaching Characteristics of Aged Ziram: ABC Re- port #33364. Unpublished 

study prepared by Analytical Bio-Chemistry Laboratories, Inc. 28 p. 

153205 Protocol

DER not 

located

Analytical Bio-Chemistry Labs., Inc. (1985) Soil/Sediment Adsorption/ Desorption: [Ziram]: Rev. 

ABC Protocol #M-8007: Study No. 33368. Unpublished study. 13 p. 

153206 Protocol

DER not 

located

Analytical Bio-Chemistry Labs., Inc. (1985) Leaching Characteristics in Soil: ABC Protocol #M8102: Study No. 33365. Unpublished study. 14 p. 
34

5001190 Open Lit

DER not 

located

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

64(8):1091-1100. 

43873501 2005694 Spare, W. (1995) Adsorption/Desorption of (carbon 14)-Ziram: Lab Project Number: 2526: IDC 

433102: 94072. Unpublished study prepared by Agrisearch Inc. 162 p. 

164-1 Terrestrial field dissipation

MRID Citation Reference

40061603 2005669 Selman, F. (1987) Ziram Soil Dissipation Study: ABC Preliminary Report #35028. Unpublished 

study prepared by Analytical Bio- Chemistry Laboratories, Inc. in cooperation with Morse 

Laboratories, Inc. 112 p. 

40061604 2005668 Selman, F. (1987) Ziram Soil Dissipation Study: ABC Preliminary Report #35029. Unpublished 

study prepared by Analytical Bio- Chemistry Laboratories, Inc. in cooperation with Morse 

Laboratories, Inc. 109 p.

44548301 2005688 Novak, R.; Binari, L. (1998) Terrestrial Field Dissipation of Ziram 76 DF Fungicide in North 

Carolina: Final Report: Lab Project Number: F96-7204: GR96255: 96-0030. Unpublished study 

prepared by Grayson Research, Ltd., EN-CAS Analytical Laboratories, and NPC, Inc. 428 p. 

44548302 2005688 Novak, R.; Binari, L. (1998) Terrestrial Field Dissipation of Ziram 76 DF Fungicide in California: 

Final Report: Lab Project Number: F96-7203: R319601: ML96-0606-ZTF. Unpublished study 

prepared by Research for Hire, Morse Laboratories, Inc., and NPC, Inc. 401 p. 

46545601 2030918 Reibach, P. (2005) Terrestrial Field Dissipation of Ziram. Project Number: KP/2005/13. 

Unpublished study prepared by Cerexagri, Inc. 20 p.

ACC 

259584

2005672 Warren, J. 1985. ABC # 33368

Non-Guideline Study

MRID Citation Reference

146901 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Soil/Sediment Adsorption-Desorption": 

[Protocol only--Protocol #M-8007]. Un- published study. 9 p. 

146902 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Leaching Characteristics of Soil Incorporated 

Test Material following Aerobic Aging": [Protocol only--Protocol #M-8406]. Unpublished study. 15 

p. 

146903 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Leaching Characteristics in Soil": [Protocol 

only--Protocol #M-8102]. Unpublished study. 9 p. 

146904 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Determination of Hydrolysis Rate": [Protocol 

only--Protocol #M-8201]. Unpublished study. 9 p. 

146905 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Determination of Photolysis Rate": [Protocol 

only--Protocol #M-8301]. Unpublished study. 9 p. 

146906 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Determination of Photolysis Rate on the 

Surface of Soil": [Protocol only--Protocol #M-8304]. Unpublished study. 12 p. 

146907 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Aerobic Soil Metabolism": [Protocol only--

Protocol #M-8001]. Unpublished study. 13 p. 

146908 

protocol

Protocol

2005655

Analytical Bio-Chemistry Laboratories, Inc. (1984) "Anaerobic Soil Metabolism": [Protocol only--

Protocol #M-8002]. Unpublished study. 13 p. 

154984 Open Lit

Klisenko, M.; Vekshtein, M. (1971) Kinetics of the hydrolysis of metal complexes of 

dialkyldithiocarbamic and ethylenebisdithio- carbamic acids in their dependence on the pH of the 

medium, and identification of their transformation products. J. Gen. Chem. of the U.S.S.R. 

41(5):1125-1130. 

40497300 Response Penwalt Corp. (1988) Submission of Hydrolysis Rate in Response to Groundwater Data Call-in for 

Ziram. Transmittal of 1 study. 
35

N.A. 2005654 1990 Fate Database Oneliner Report

2005659 Protocol for Terrestrial Field Dissipation study 1986

ACC 

258212

2005667 Lemal, R. 1984. Ziram Determination of Octanol Water partition coefficient

2005679 1990 Fate Data Summary

2005680 Lab Audit for Soil Dissipation Study

10.2. Submitted Ecological Toxicity Studies

MRID Citation

TN 1021 McCann, J.A. 1976. 24 hour LC50 with Rainbow trout and 76% ai = 300 PPB

00036935 Atkins, L., Jr.; Anderson, L.D. (1967) Toxicity of Pesticides and Other Agricultural Chemicals to 

Honey Bees: Laboratory Studies. (Unpublished study received Jan 30, 1969 under 9G0802; prepared by 

Univ. of California--Riverside, Dept. of Entomology, submitted by Hercules, Inc., Agricultural 

Chemicals, Wilmington, Del.; CDL:093111-D)

00138214 

(ACC 

72559)

Dickhaus, S.; Heisler, E.; Reinhard. (1980) Examination for Acute Toxicity of Ziram in Rainbow-trout 

at Exposition of 96 Hours in the Bath Fliud: Report ID:1-7-139-80. (Unpublished study received Apr 

10, 1984 under 3F2964; prepared by Pharmatox Forcshung und Beratung GmbH, W. Ger., submitted by 

Rhone- Poulenc, Inc., Monmouth Junction, NJ; CDL:072559-A)

00138215 

(ACC 

72559)

Dickhaus, S.; Heisler, E. (1980) Examination for Acute Toxicity of Ziram in Carp at Exposition of 96 

Hours in the Bath Fluid: Report ID:1-7-140-80. (Unpublished study received Apr 10, 1984 under 

3F2964; prepared by Pharmatox Forschung und Beratung GmbH, W. Ger., submitted by RhonePoulenc, Inc., Monmouth Junction, NJ; CDL:072559-B)

05003523 Maloney, T.E.; Palmer, C.M. (1956) Toxicity of six chemical compounds to thirty cultures of algae. 

Water and Sewage Works 103:509-513.

05003523 Maloney, T.E.; Palmer, C.M. (1956) Toxicity of six chemical compounds to thirty cultures of algae. 

Water and Sewage Works 103:509-513.

40228401 Mayer, F. (1986) Acute Toxicity Handbook of Chemicals to Estuarine Organisms: EPA/600/X/86/231. 

Prepared by US EPA Environmental Research Laboratory, Gulf Breeze, Fl. 275 p.

41340401 Liggett, M. and S. Allan (1989) Acute oral toxicity to rats of Ziram. Huntingdon Research Centre Ltd., 

P.O. Box 2, Huntingdon, Cambridgeshire, PE18 6ES, England. HRC Study Report No. 89690D/UCB 

315/AC, November 30, 1989.

41442001 Jackson, G. and C. Hardy (1989) Ziram Technical: Acute inhalation toxicity in rats - 4-hour exposure. 

Huntingdon Research Centre Ltd., P.O. Box 2, Huntingdon, Cambridgeshire, PE18 6ES, England. 

HRC Report No. UCB 314/89684, December 4, 1989.

41667901 Cole, J. (1989) The Acute Contact Toxicity to Honeybees of Technical Ziram: Final Report: Lab Project 

Number: ZIR 21/891454. Unpublished study prepared by Huntingdon Research Centre, Ltd. 21 p.

41725701 Hakin, B.; Norman, A. (1989) Acute Oral Toxicity (LD50) of Ziram to the Bobwhite Quail: Lab Project 

Number: ZIR 17/90566. Unpublished study prepared by Huntingdon Research Centre Ltd. 29 p.

42386301 Hakin, B.; Norman, A.; Anderson, A.; et al. (1992) The Dietary Toxicity (LC50) of Ziram Technical to 

the Bobwhite Quail: Final Report: Lab Project Number: ZIR 19/901457. Unpublished study prepared by

Huntingdon Research Centre Ltd. 32 p.

42386302 Hakin, B.; Norman, A.; Anderson, A.; et al. (1992) The Dietary Toxicity (LC50) of Ziram Technical to 

the Mallard Duck: Final Report: Lab Project Number: ZIR 18/901456. Unpublished study prepared by 

Huntingdon Research Centre Ltd. 32 p.

42386303 Douglas, M.; Stonehewer, R.; Macdonald, I. (1991) The Acute Toxicity of Ziram Technical to Bluegill 

Sunfish (Lepomis macrochirus): Final Report: Lab Project Number: ZIR 20(C)/901626. Unpublished 

study prepared by Huntingdon Research Centre Ltd. 27 p.

42386304 Douglas, M.; Bell, G.; Macdonald, I. (1991) The Acute Toxicity of Ziram Technical to Rainbow Trout 

(Oncorrhynchus mykiss): Final Report: Lab Project Number: ZIR 20(B)/891173. Unpublished study 

prepared by Huntingdon Research Centre Ltd. 28 p.
36

42386305 Douglas, M.; Bell, G.; Macdonald, I. (1991) The Acute Toxicity of Ziram Technical to Daphnia magna: 

Final Report: Lab Project Number: ZIR 20(A)/901625. Unpublished study prepared by Huntingdon 

Research Centre Ltd. 25 p.

43781601 Machado, M. (1995) Ziram--Acute Toxicity to Sheepshead Minnow (Cyprinodon variegatus) Under 

Flow-Through Conditions: Final Report: Lab Project Number: 95-6-5949: 13561.0395.6106.505. 

Unpublished study prepared by Springborn Labs, Inc. 77 p.

43781602 Dionne, E. (1995) Ziram--Acute Toxicity to the Eastern Oyster (Crassostrea virginica) Under FlowThrough Conditions: Final Report: Lab Project Number: 95-7-5965: 13561.0395.6108.504. 

Unpublished study prepared by Springborn Labs, Inc. 83 p.

43781603 Machado, M. (1995) Ziram--Acute Toxicity to Mysids (Mysidopsis bahia) Under Flow-Through 

Conditions: Final Report: Lab Project Number: 95-7-5967: 13561.0395.6107.515. Unpublished study 

prepared by Springborn Lab., Inc. 81 p.

43833901 Hoberg, J. (1995) Ziram--Toxicity to the Freshwater Green Alga, Selenastrum capricornutum: 

Amended Final Report: Lab Project Number: 95-7-5971: 13561.0395.6101.430. Unpublished study 

prepared by Springborn Labs, Inc. 77 p.

43935801 Nemec, M.D. (1996) A dietary two-generation reproduction and developmental neurotoxicity study of 

ziram in rats, WIL Research Laboratories, Inc., 1407 George Road, Ashland, OH 44805-9281. 

Laboratory study number WIL-223003, January 30, 1996.

46622301 Frey, L.; Martin, K.; Beavers, J.; et. al. (2000) Ziram Technical: A Reproduction Study with the 

Northern Bobwhite: Final Report. Project Number: 299/104. Unpublished study prepared by Wildlife 

International, Ltd. 163 p.

46823301 Palmer, S.; Kendall, T.; Krueger, H. (2006) Ziram: A Flow-Through Life-Cycle Toxicity Test With The 

Cladoceran (Daphnia magna): Final Report. Project Number: 602A/101. Unpublished study prepared by 

Cerexagri, Inc. and Taminco, n.v. 57 p.

46823302 Desjardins, D.; Kendall, T.; Krueger, H. (2006) Ziram: A 7-Day Static-Renewal Toxicity Test with 

Duckweed (Lemna gibba G3): Final Report. Project Number: 602A/105. Unpublished study prepared 

by Cerexagri, Inc. and Taminco, n.v. 44 p.

46856401 Sutherland, C.; Kendall, T.; Krueger, H. (2006) Ziram: An Early Life-Stage Toxicity Test with the 

Sheepshead Minnow (Cyprinodon variegatus): Final Report. Project Number: 602A/104. Unpublished 

study prepared by Wildlife International, Ltd. 73 p.

46893101 Porch, J.; Krueger, H. (2006) Ziram: A Toxicity Test to Determine the Effects of the Test Substance on 

Seedling Emergence of Ten Species of Plants Grown Under Greenhouse Conditions: Final Report. 

Project Number: 602/102, KP/2006/21, 602/080505/SEEDEM/10/SUB602. Unpublished study 

prepared by Wildlife International, Ltd and Cerexagri, Inc. 138 p.

46893102 Porch, J.; Krueger, H. (2006) Ziram: AToxicity Test to Determine the Effects of the Test Substance on 

Vegetative Vigor of Ten Species of Plants Grown Under Greenhouse Conditions: Final Report. Project 

Number: 602/103, KP/2006/22, 602/080505/VEGVIG10/GH/SUB602. Unpublished study prepared by 

Wildlife International, Ltd and Cerexagri, Inc. 175 p.

46893103 Sutherland, C.; Kendall, T.; Krueger, H. (2006) Ziram: A Flow-Through Life-Cycle Toxicity Test With 

Saltwater Mysid (Mysidopsis bahia): Final Report. Project Number: 602A/102A. Unpublished study 

prepared by Wildlife International, Ltd. 72 p.

46893104 Palmer, S.; Kendall, T.; Krueger, H. (2006) Ziram: An Early Life-Stage Toxicity Test with Fathead 

Minnow (Pimephales promelas): Final Report. Project Number: 602A/103A. Unpublished study 

prepared by Wildlife International, Ltd. 66 p.

47286501 Temple, D.; Martin, K.; Beavers, J.; et al. (2007) Ziram: A Reproduction Study with the Mallard: Final 

Report. Project Number: 602/104, KP/029/01, KP/2006/45. Unpublished study prepared by Cerexagri, 

Inc., Taminco, n.v. and Wildlife International, Ltd. 263 p.

47307901 Palmer, S.; Kendall, T.; Krueger, H. (2007) Ziram: A 96-hour Flow-Through Acute Toxicity Test With 

the Bluegill (Lepomis macrochirus): Final Report. Project Number: 602A/107. Unpublished study 

prepared by Wildlife International, Ltd. 37 p.

47405701 Palmer, S.; Kendall, T.; Krueger, H. (2008) (Carbon 14)-Ziram: A 48-hour Flow-Through Acute 

Toxicity Test with the Cladoceran (Daphnia magna): Final Report. Project Number: 602A/108. 

Unpublished study prepared by Wildlife International, Ltd. 38 p.

47405702 Palmer, S.; Kendall, T.; Krueger, H. (2008) (Carbon 14)-Ziram: A 96-hour Flow-Through Acute 

Toxicity Test with the Saltwater Mysid (Americamysis bahia): Final Report. Project Number: 

602A/109. Unpublished study prepared by Wildlife International, Ltd. 37 p.
37

47435501 Palmer, S.; Kendall, T.; Krueger, H. (2008) Ziram: A Flow-Through Life-Cycle Toxicity Test with the 

Fathead Minnow (Pimephales promelas). Project Number: 602A/106A, RL/13/2/1. Unpublished study 

prepared by Wildlife International Ltd. 131 p.

48115201 Piccirillo, V. (2010) Response to Data Evaluation Record for: A Reproduction Study on Mallard Duck 

with Ziram (MRID 47286501). Project Number: 2010/1. Unpublished study prepared by VJP 

Consulting, Inc. 6 p.

48115701 Sutherland, C.; Kendall, T.; Krueger, H. (2006) Ziram: A Flow-Through Life-Cycle Toxicity Test with 

the Saltwater Mysid (Mysidopsis bahia). Project Number: 602A/102A. Unpublished study prepared by 

Wildlife International, Ltd. 23 p.
38

Appendix A. SIP Modeling Results

Table 1. Inputs

Parameter Value

Chemical name Ziram

Solubility (in water at 25oC; mg/L) 0.967

Mammalian LD50 (mg/kg-bw) 320

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Mammalian NOAEL (mg/kg-bw) 14.8

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian 

species

Avian LD50 (mg/kg-bw) 97

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 29

Bobwhite quail NOAEC (mg/kg-diet)

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.1663 0.1663

Adjusted toxicity value (mg/kg-bw) 246.1314 11.3836

Ratio of exposure to toxicity 0.0007 0.0146

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.7833 0.7833

Adjusted toxicity value (mg/kg-bw) 69.8817 1.4388

Ratio of exposure to acute toxicity 0.0112 0.5444

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Drinking water exposure 

alone is NOT 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.
39

Appendix B. STIR Modeling Results

Input

Application and Chemical Information

Enter Chemical Name Ziram

Enter Chemical Use Fungicide

Is the Application a Spray? (enter y or n) y

If Spray What Type (enter ground or air) air

Enter Chemical Molecular Weight (g/mole) 307.5

Enter Chemical Vapor Pressure (mmHg) 1.35E-07

Enter Application Rate (lb a.i./acre) 7.6

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 97

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 320

Enter Lowest Rat Inhalation LC50 (mg/L) 0.06

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) 2.23E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.81E-04

Adjusted Inhalation LD50 1.01E-01

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.77E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 7.30E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 7.20E+00 Proceed to Refinements

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 2.23E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 3.53E-04

Adjusted Inhalation LD50 3.57E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 9.88E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 9.18E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 2.57E-01 Proceed to Refinements
40

Appendix C. Summary of Ziram and Thiram Fate and 

Transport Data

I. Abiotic Degradation

161-1 Hydrolysis 

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.

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 

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 
41

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.

II. Metabolism

162-1 Aerobic Soil Metabolism 

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 

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 

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 
42

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 

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-1. 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

Based on Batch Equilibrium studies, ziram, at five concentrations ranging from 0.2 to 4.0 ppm 

and in four soil types with %OC ranging from 0.2 to 1.8, appeared to be moderately mobile in 

sand, silt loam and sandy loam soils, but shows low mobility in a clay soil. The samples were 

equilibrated for up to 24 hours. The Freundlich, Kads and KOC constants ranged from 2.9 to 7.6 

and 314 to 1232, respectively, for three of the soils tested. For the clay soil, Kads=68.1, and 

KOC=3732. The Freundlich, Kdes constants ranged from 40 to 4093 for the four soils tested.
43

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 

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.

The registrant conducted two terrestrial field dissipation studies for ziram. Although both studies 

were on bareground, they were representative of typical use sites, as well as the East and West 

coasts of the US. One was conducted on a sand soil in Wake County, NC (peaches), and the 

other was conducted on a sandy loam soil in Tulare County, CA (almonds). The product used 

was Ziram 76 DF®, which was broadcast applied nine times (at 7- to 10-day intervals) as a spray 

to bareground plots at 8 lb/A/application. Ziram, dissipated from the 0- to 3-inch soil depth with 

initial half-lives of 6.7 days and 5.2 days (0- to 10-day data in both cases) following the ninth 

application, at the North Carolina and California sites, respectively. The dissipation appeared to 

become slow after the first two weeks. The subsequent half-lives were 144 days (15- to 539-day 

data) and 206 days (14- to 540-day data), respectively. These studies, however, can only be 

considered supplemental at this time because storage stability data were inadequate for the parent 

compound (both sites) and the degradate 1,1-dimethylurea (California site). In addition, at the 

North Carolina site, Hurricane Fran delivered approximately 8 inches of rain eight days 

following the ninth application. Furthermore, the California study presents difficulties in the 

interpretation of data because there was high variability in the data from day 0 to 10 days posttreatment. 
44

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
45

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
46

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
47

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
48

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
49

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
50

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
51

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.

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
52

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)

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 the Tier I test. 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.
53

Appendix E. Thiram – Preliminary Identification of Data Gaps 

The following data gaps tables are from the thiram problem formulation (USEPA, 2015).

E.1. Environmental Fate Data

Table E-1 identifies environmental fate studies by MRID for thiram 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.

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 E-1. 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

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
54

E.2. Effects Data

Tables E-2 and E-3 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.

Table E-2. 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

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)
55

OCSPP

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

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.

850.4550 Cyanobacteria None NA Yes

A cyanobacteria will 

reduce uncertainty in the 

assessment of risk to nonvascular plants.

Table E-3. 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
56

OCSPP 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

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.

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.
57

OCSPP 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are Additional

Data Needed to 

Conduct Risk 

Assessment?

Current Additional Data 

Need

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.