1

OFFICE OF

CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

PC Code: 113961

DP Barcode: D427289

Date: December 7, 2015

MEMORANDUM

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

Ecological Risk, Endangered Species, and Human Health Drinking Water 

Exposure Assessments for Prothioconazole

TO: Brian Kettl, Chemical Review Manager

Tom Myers, Team Leader

Risk Management and Implementation Branch 2

Pesticide Re-Evaluation Division (7508P)

FROM: Mary Clock-Rust, Biologist

Cheryl Sutton, Ph.D., Environmental Scientist

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

REVIEWED

BY: Catherine Aubee, Senior Effects Scientist

James N. Carleton, Ph.D., Senior Fate Scientist

Katrina White, Ph.D., Risk Assessment Process Leader

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)

THROUGH: Jean Holmes, D.V.M., M.P.H., Branch Chief

Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P)
2

1. Executive Summary

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

problem formulation (attached) for the ecological risk, environmental fate, endangered species, 

and drinking water assessments to be conducted as part of the Registration Review of 

prothioconazole (2-(2-(1-chlorocylocpropyl)-3-(2-chlorophenyl)-2-hydroxy-propyl)-2,4-

dihydro(1,2,4)-triazol-3-thion; PC Code 113961; CAS No. 178928-70-6). 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, and potential risks associated with the use of 

prothioconazole as well as uncertainties unique to risk assessment of prothioconazole. This 

document also identifies additional studies that would be beneficial to the conduct of an 

ecological risk assessment. Major findings include:

• The environmental fate database is relatively complete, with some exceptions. In all of 

the metabolism studies, it is uncertain whether or not greater amounts of soil-bound 

material could have been extracted using harsher or more appropriate methods. For the 

parent compound, an aerobic soil metabolism study is needed on an additional soil, and 

an anaerobic aquatic study is need on an additional sediment/water system. For each of 

the studies, it is important that the extraction is more rigorous than that which was used in 

previously submitted studies, and that the nature of the unextracted residues be clarified 

to the extent possible. Guidance is available at http://www2.epa.gov/pesticide-scienceand-assessing-pesticide-risks/guidance-addressing-unextracted-pesticide-residues.

• In the event that new, useful information is not received on unextracted residues, which

may be applied to the understanding of previously submitted studies as well, unextracted 

residues will continue to be considered as parent compound and continue to be treated as 

such in exposure modeling.

• More information is needed to address uncertainties in the ecological effects database for 

prothioconazole and its degradates. There are significant toxicity data gaps for the parent 

compound as well as the major prothioconazole degradates (prothioconazole-desthio, 

prothioconazole-S-methyl).

Ecological effects data needs: 

Prothioconazole Parent Compound

o Non-guideline: Chronic toxicity to benthic invertebrates (whole sediment; 3 test 

species: freshwater amphipod, freshwater midge, and estuarine/marine amphipod) 

(TGAI)

 EFED recommends that the registrant consider Agency-wide guidelines 

for chronic testing of freshwater and estuarine/marine organisms, because 

the 850 guidelines are in the process of being finalized. A protocol must 

be submitted for review prior to initiating the studies.

o OCSPP 850.2100: Acute Oral Toxicity with passerine species (TGAI)

o OECD TG 237 and Non-guideline special studies: Honeybee larval acute and 

chronic oral toxicity studies (TGAI)

o Non-Guideline: Honey bee adult chronic oral toxicity test (TGAI)
3

o Special study OECD TG 75 and OSCPP 850.3040: Semi-field testing for 

pollinators (Tier II) and Field testing for pollinators (Tier III) (both studies that 

are conditionally required based on the results of the Tier I – laboratory based 

studies listed above; if needed these additional field studies will be discussed 

pending the results of the acute and chronic adult and larval oral toxicity studies 

to honey bees and/or Tier II studies (for the full field study); (TEP).

Prothioconazole-Desthio

o OCSPP 850.1010: Acute toxicity for freshwater invertebrates

o OCSPP 850.1075:Acute toxicity for estuarine/marine fish

o OCSPP 850.1400 Early life stage toxicity test with freshwater fish 

o OCSPP 850.4500 Algal Toxicity with Non-vascular estuarine/marine diatom

o OCSPP 850.2100: Acute Oral Toxicity with avian passerine species 

Prothioconazole-S-methyl

o OCSPP 850.1025, 850.1035, 850.1045, 850.1055: Acute toxicity to 

estuarine/marine invertebrates 

Uncertainties

The fate database for prothioconazole indicates that it degrades into other compounds 

(prothioconazole-desthio, prothioconazole-S-methyl and 1,2,4-triazole, among other degradates). 

For each of the degradates, there are significant uncertainties associated with the toxicity to nontarget organisms. Those data that are the most critical for a complete and robust risk assessment 

have been identified in this document. Where possible, EFED will make use of limited data to 

inform the risk assessment. For example, chronic data for estuarine/marine fish conducted with 

prothioconazole-desthio were not submitted by the registrant. However, measurement endpoints 

can be estimated based on an acute-to-chronic ratio (ACR) for freshwater fish if a chronic 

freshwater fish toxicity study (850.1400) is submitted for the most sensitive species tested in the 

acute toxicity study (850.1075; Rainbow trout, Oncorhynchus mykiss).

2. Introduction

Prothioconazole is a broad-spectrum, systemic fungicide belonging to the conazole

(triazolinthione) class of fungicides. This class of compounds is characterized structurally by 

inclusion of a nitrogen-containing five member ring (azole). Prothioconazole is currently the 

sole fungicide in triazolinthiones, which was added in 2012 to the Group 3 of DMI 

(DeMethylation Inhibitor) fungicides classified by the Fungicide Resistance Action Committee. 

Conazole fungicides act through disruption of normal fungal cell membrane structure and 

function primarily through interactions or inhibitions of ergosterol synthesis, the predominant 

membrane sterol component. Prothioconazole’s specific mode of action is through the inhibition 

of demethylation of two precursors of sterols in fungi (lanosterol and 24-methylene dihydrolanosterol). 

Prothioconazole is applied via ground or aerial spray, prior to and during specified 

growth phases of the target crops. It is also used as a seed treatment on multiple crops. More 

complete information on applications of prothioconazole is provided in the Biochemical Profile 
4

(BCP) that was developed for prothioconazole by the Biologic and Economic Analysis Division 

(BEAD; USEPA, 2015b).

EFED evaluated the most recent ecological risk assessments for prothioconazole 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 a 2012 assessment for the new use of prothioconazole on seeds of cereal 

grains crop groups 15 & 16 (except sorghum and rice), as a seed treatment on corn (field, sweet, 

pop), and as a foliar treatment on soybean at an increased rate (USEPA 2012b.); and a 2012 new 

use assessment on bushberry (crop subgroup 13-07b), low growing berry subgroup, except 

strawberry (crop subgroup 13-07h) and cucurbit vegetables (crop group 9; USEPA, 2012c). In 

addition, EFED considered the latest Agency science policies and risk assessment 

methodologies. The structure of prothioconazole, as well as the chemical names and other 

identifiers can be found in Table 3.

3. Use Characterization

Prothioconazole is registered for use on a variety of crops, with the majority of use (total 

pounds applied to crops) on wheat, corn, sugar beets, peanuts, dry beans/peas, soybeans and 

barley (USEPA 2015a). Prothioconazole is also registered for use on alfalfa, beans, bushberries, 

rice, small grains, crambe, cucurbits, mustard, potatoes, small fruit, cranberries, and nursery 

stock. It is registered for use as a seed treatment on multiple crops, including cereal grains and 

potatoes (USEPA, 2015b). It is not registered for use on any non-agricultural sites.

Based on the BEAD Chemical Profile (BCP) produced by BEAD (USEPA 2015b; 

located in the docket), prothioconazole has been used to control or suppress some important crop 

diseases such as anthracnose leaf blight on corn, Ascochyta blight on dry beans/peas, white mold 

on peanuts, frog eye leaf spot on soybeans, Rhizoctonia solani on sugar beets, and Fusarium head 

blight (scab) on wheat. Prothioconazole is registered for use on nursery stock, such as nursery 

seedlings of loblolly pine, to control pitch canker and other diseases. The agricultural use of 

prothioconazole in the United States has been increasing since its registration in 2007, treating a 

total of approximately 11,000,000 acres in 2013 for all crops combined (USEPA 2015b). 

Prothioconazole is formulated as a liquid soluble concentrate, emulsifiable concentrate, 

and flowable concentrate. There are multiple pesticide products containing prothioconazole and 

other active ingredients, such as Stratego 731® and Stratego YLD® (containing 10% 

prothioconazole and 32.3% trifloxystrobin, PC code 129112) and Evergol Energy® [containing 

7.18% prothioconazole, 3.59% penflufen (PC code: 100249) and 5.74% metalaxyl (PC code 

113501)]. Prothioconazole is applied using broadcast, banded, chemigation, and seed treatment 

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

given use for the risk assessment.

4. Conclusions from Previous Risk Assessments

The Agency has conducted multiple environmental fate and ecological risk assessments 

on prothioconazole that serve as a basis for this scoping document, including the initial new 
5

chemical risk assessment in 2006 and several subsequent new use assessments over the past 8

years (USEPA 2006d, -2008, -2010b, -2012b).

a. Ecological Risk Assessment 

The results of previous screening-level risk assessments indicate that the uses of 

prothioconazole have the potential for direct adverse effects to Federally-listed threatened or 

endangered species (hereafter referred to as “listed”) and non-listed organisms. Based on 

previous conservative screening level assessments, level-of-concern (LOC) exceedances were 

calculated for registered uses of prothioconazole. The registered uses were determined to have

the potential for direct adverse effects to listed freshwater fish and aquatic-phase amphibians, 

freshwater invertebrates, estuarine/marine invertebrates, mammals, listed and non-listed vascular 

and non-vascular aquatic plants and listed semi-aquatic dicot plants. Also, as shown in previous 

risk assessments, registered uses of prothioconazole have the potential for direct adverse effects 

to aquatic and terrestrial plants and mammals (on a chronic exposure basis). 

The major ecological risk and exposure conclusions from previous assessments are 

summarized in Table 1.

Table 1. Major Risk and Exposure Conclusions from Previous Prothioconazole Risk

Assessments

Birds Mammals Terr.

Plants

Terr.

Inverts Fish BCF Aquatic Inverts

Aquatic 

Plants

Groundwater 

Contamination Persistence Degradates of Concern

-- √ √ NA √ -- √ √ √ √ √

√ = at least one LOC has been exceeded in previous assessments; NA = RQs have not been calculated previously.

b. Drinking Water Exposure Assessments

Prothioconazole degrades relatively quickly in the environment (decreased to 7.9-52.1 % 

of the applied by 1 day in aerobic soil); however, its degradates, primarily prothioconazoledesthio and prothioconazole-S-methyl, are more persistent than the parent. As documented in 

previous prothioconazole assessments, a total toxic residues approach has been used for drinking 

water exposure modeling. Combined residues of concern include the parent and the two 

degradates stated above, plus unextracted residues which could not be ruled out as consisting of 

parent compound based on the minimal extraction techniques used. The 1,2,4-triazole degradate, 

which has different toxicity endpoints from prothioconazole with respect to human health, was 

characterized in a separate, cumulative triazole assessment and was, therefore, not considered 

separately in previous drinking water assessments (DWA). 

A drinking water exposure assessment for the proposed new uses on Crop Subgroup 13-

07B (bushberry) and Crop Group 9 (cucurbit vegetables) was conducted for prothioconazole in 

2012 (USEPA, 2012c). The maximum application rates for bushberry and cucurbit vegetables 

were not higher than the application rates assessed in previous DWAs (USEPA 2010; USEPA 

2012a). Because those new uses would result in lower EDWCs than in the previous DWAs, the 

new uses were not modeled separately to determine surface water EDWCs. Instead, previously 

determined estimated drinking water exposure (EDWC) values were cited, although new values 
6

were determined based on changes in the percentage crop area (PCA) factor that were 

implemented since the former assessment was completed. The surface water acute (1-in-10-year 

peak) EDWC, based on corn use, increased slightly relative to the previous assessment, from 

94.7 to 99.0 μg/L. The chronic (1-in-10-year annual mean) and cancer (30-year mean) EDWCs, 

based on the cranberry use, increased to 91.9 μg/L from previous values of 84.3 μg/L (chronic, 

based on corn use) and 76.2 μg/L (cancer, based on rice use). The acute and chronic EDWCs 

(both 0.83 μg/L) provided for groundwater sources of drinking water were not updated from the 

most recent DWA. Groundwater EDWCs were based on use on nursery seedlings and were 

determined using the SCI-GROW model. 

EDWCs for the prothioconazole degradate 1,2,4-triazole, were calculated in support of 

the 2006 aggregate assessment for triazole-derivative fungicides, including fenbuconazole 

(USEPA, 2006a, 2006b). The highest 1,2,4-triazole EDWCs calculated were for the turf use, 

which resulted in the surface water EDWCs (using PRZM-EXAMS) of 0.041 mg/L (acute), 

0.011 mg/L (chronic) and 0.0027 mg/L (cancer). A groundwater EDWC of 0.001 mg/L was 

calculated for 1,2,4-triazole using SCI-GROW. The 1,2,4-triazole application rate used to 

determine EDWCs was based on a turf use and was obtained from molecular weight conversion 

times myclobutanil application rate times max percent formation rate for triadimefon (turf = 

(69.0/288.78)*1.73*0.307), as this was believed to be the maximum percent formation rate for 

all fungicides in the conazole class.

c. Clean Water Act Programs

Prothioconazole is not identified as a cause of impairment for any water bodies listed as 

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

(http://water.epa.gov/lawsregs/lawsguidance/cwa/tmdl/intro.cfm). No Total Maximum Daily 

Load (TMDL) criteria have been developed for prothioconazole. Aquatic benchmarks have not 

been established for prothioconazole (http://www2.epa.gov/pesticide-science-and-assessingpesticide-risks/aquatic-life-benchmarks-pesticide-registration). 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

Prothioconazole [2-[2-(1-Chlorocyclopropyl)-3-(2-chlorophenyl)-2-hydroxypropyl]-

1,2-dihydro-3H-1,2,4-triazole-3-thione; CAS No. 178928-70-6; PC code 113961] dissipates in 

the environment by aqueous photolysis and microbial degradation in soil. Prothioconazole is 

stable to hydrolysis. Prothioconazole photolyzes in shallow, clear surface waters (half-life of 9.7

days), but does not photolyze on soil. In water, it degrades to prothioconazole-desthio, which 

appears to resist further photolytic degradation (residues of concern t1/2 = 101 d). In soil, 

prothioconazole degrades relatively quickly to two major persistent degradates which are 

assumed to be of similar toxicity to that of the parent (based on structural similarity), 

prothioconazole-desthio and prothioconazole-S-methyl. Prothioconazole and its degradates are 

not expected to volatilize appreciably (vapor pressure 3 x 10-9 torr). Parent prothioconazole 
7

rapidly degrades in aerobic soil (in submitted data, decreased to 7.9-52.1 % of the applied by 1 

day and was <2.0-23.2 % of the applied by 7 days). However, based on available data, 

prothioconazole together with its major degradates do not appear to undergo significant 

microbial degradation in soil (t1/2 = 462 – 1386 d) or in water (t1/2 = 67 – 433 d), so may 

potentially accumulate in soil or in the sediment of aquatic environments with repeated 

application. The mobility of parent prothioconazole has not been successfully characterized due 

to rapid degradation that occurred during mobility studies. However, the major degradate that 

formed in the largest amounts (prothioconazole-desthio) is moderately mobile based on its 

organic carbon partition coefficient (Koc = 523 – 625 mL/goc) and the Food and Agriculture 

Organization soil mobility classification scheme (FAO, 2000). The other major degradate,

prothioconazole-S-methyl, which is formed in smaller relative amounts, is slightly mobile (Koc = 

1973 – 2993 mL/goc). These two major degradates were considered to be of similar or greater 

toxicity compared with the parent and were included in previous aquatic exposure estimates (see 

USEPA 2006d). There is potential for the degradates prothioconazole-desthio and 

prothioconazole-S-methyl to leach to groundwater in vulnerable aquifers, such as those 

underlying coarse-textured soils low in organic matter. Prothioconazole and prothioconazoledesthio do not appear to bioconcentrate in fish and are not expected to bioaccumulate in aquatic 

ecosystems, although a BCF cannot be calculated due to lack of a clear accumulation plateau.

Terrestrial field data show that prothioconazole parent dissipates from the top layer of 

soil quickly (with a DT50 of less than 2 or 3 days), but that prothioconazole-desthio dissipates 

from the top layer of soil much more slowly (DT50 of 85-315 days). Prothioconazole was not 

detected below 15 cm in any of the three tested fields in California, Georgia or New York. 

Prothioconazole-desthio was detected at levels above the LOQ down to 30 cm and at levels 

above the minimum detection limit [MDL] but below the LOQ down to 45 cm in one replicate in 

the California field study, and at levels below the LOQ at one to two sampling times in the 

Georgia and New York field studies. Prothioconazole-S-methyl was detected below 15 cm only 

in a single replicate (below LOQ) in the field study in California. 

Persistence was observed in aquatic field dissipation studies, with long half-lives for both 

prothioconazole and prothioconazole-desthio in sediment (DT50 of 90-204 days). Dissipation 

half-lives in paddy water were extremely short (0.6-1.7 days), likely more due to adsorption than 

degradation given the compound’s slow rate of biotic degradation in lab studies and its 

photolysis half-life of almost 10 days in clear shallow water. Prothioconazole was detected at

only three sampling intervals at concentrations below the LOQ but above the MDL in sediment 

below 3 inches. Prothioconazole-desthio was detected at 3-6 inch deep sediment through 28 

days after treatment (DAT) in the Arkansas flooded field and through 60 DAT in the Arkansas 

flooded and cropped field. Prothioconazole-S-methyl was detected below 3 inches in sediment 

only, at three sampling intervals in the Arkansas flooded and cropped field.

A selection of environmental fate and transport properties of prothioconazole is 

summarized Table 2.
8

Table 2. Chemical Properties and Environmental Fate Parameters of Prothioconazole.

Parameter Value Description/Comments Source

Selected Physical/Chemical Parameters

Molecular mass 

(molecular formula) 344.26 g/mol − MRID 46246003

Vapor pressure (20°C) 3 x 10-9 Torr Limited volatilization. MRID 46246003

Aqueous solubility 

(20°C)

pH 4: 5 mg/L or ppm

pH 8: 300 mg/L or ppm

pH 9: 2000 mg/L

Readily soluble. Solubility 

increases with increases in 

pH.

MRID 46246003

Henry’s Law Constant 

(20°C) 2.96 x 10-10 atm-m3

/mol Not expected to volatilize 

from water or wet surfaces MRID 46246003

Log octanol-to-water 

partition coefficient

(log KOW; 20 o

C)

Unbuffered: 4.05

pH 4: 4.16

pH7: 3.82

pH9: 2.00

Potential for 

bioaccumulation at neutral 

and acidic pH.

MRID 46246003

Acid dissociation 

constant (pKa; 20 o

C) 6.9 (parent compound) Weak acid, anion at neutral 

and alkaline pHs. MRID 46246003

Persistence

Hydrolysis half-life 

(50°C, 25°C)

Parent prothioconazole

Stable at pH 4,7,9

Prothioconazole-desthio

Stable at pH 4,7,9

Do not hydrolyze. MRID’s 46246505, 

46246506

Aqueous photolysis 

half-life (pH 7; 25°C)

Prothioconazole:

9.7 days 

 

Prothioconazole-desthio:

Increasing at study termination

Prothioconazole and Prothioconazoledesthio: 101.9 days 

(Prothioconazole-S-methyl is not formed 

from prothioconazole via aqueous 

photolysis.)

Value corrected to 

represent natural sunlight 

at 40°N latitude; 

uncorrected laboratory 

half-life of 19.9 days for 

both phenyl and triazole 

labels (continuous 

irradiation; xenon lamp). 

MRID 46246507

Soil photolysis half-life 

(25°C)

Prothioconazole and Prothioconazoledesthio: stable

(Prothioconazole-S-methyl is not formed 

from prothioconazole soil photolysis.)

Half-life could not be 

calculated as parent 

degraded faster in dark 

samples than in irradiated 

samples. Phenyl label 

only. Concentration of 

prothioconazole-desthio 

was still increasing at 

study termination.

MRID 46246510 
9

Parameter Value Description/Comments Source

Aerobic soil 

metabolism half-life 

(24°C)

Prothioconazole total residues of concern:

533 days (silt; phenyl), 866 days (silt; 

triazole)

990 days (loamy sand; phenyl), 1386 days 

(loamy sand; triazole)

866 days (sandy loam; phenyl)

462 days (silty clay loam; phenyl)

 

Half-lives are based on 

combined data for parent 

prothioconazole, 

prothioconazole-desthio, 

and prothioconazole-Smethyl per sampling 

interval. Unextracted 

residues were added in as 

residues of concern. 

Analytical method may 

have been inadequate 

based on high levels of 

unextracted residues. 

Additional data obtained 

using more exhaustive 

extractions would be 

useful.

MRID’s 46246511

46246512

Aerobic aquatic 

metabolism half-life 

(25°C)

Prothioconazole total residues of concern:

433.2 days (H, total system, phenyl), 

346.6 days (H, total system, triazole)

106.6 days (A, total system, phenyl), 

67.3 days (A, total system, triazole)

17.2 days (H, water layer, phenyl), 

16.2 days (H, water layer, triazole)

23.3 days (A, water layer, phenyl), 

21.7 days (A, water layer, triazole)

Two systems studied: (H) 

Honniger Weiher pond 

(loam/water) and (A) 

Anglerweiher lake (loamy 

sand/water). Half-lives are 

based on combined data 

for parent prothioconazole, 

prothioconazole-desthio, 

and prothioconazole-Smethyl per sampling 

interval. Unextracted 

residues were added in as 

residues of concern.

MRID 46246515

Anaerobic aquatic 

metabolism half-life 

(25°C)

Prothioconazole total residues of concern:

stable (total system); 

56.8 days (water layer)

Single sediment/water 

system (Fuquay, GA pond) 

studied. Sandy clay 

loam/water, phenyl label 

only. Additional data are 

required for a second 

sediment/water system, 

with use of more 

exhaustive extractions.

Half-lives are based on 

combined data for parent 

prothioconazole, 

prothioconazole-desthio, 

and prothioconazole-Smethyl per sampling 

interval. Unextracted 

residues were added in as 

residues of concern.

MRID 46246516

Mobility
10

Parameter Value Description/Comments Source

Organic carbonnormalized Freundlich 

coefficients (KFOC)

(mL/gOC) LS SCL SL S

Prothioconazole -- -- -- --

Parent mobility cannot 

be determined due to 

instability and low 

column resolution. Very 

high sorption estimated, 

lower mobility than 

transformation products

MRID’s 46246539

46246504

Prothioconazole

-desthio 523 536 617 625

Used four soils: loamy 

sand (LS, 0.79% OC); 

silty clay loam (SCL, 

1.66% OC); sandy loam 

(SL, 2.02% OC); silt (S, 

2.14% OC). Follows 

Koc model.

MRID 46246450

Prothioconazole

-S-methyl 1973 2484 2772 2995

Used same soils as 

MRID 46246450. 

Follows Koc model. 

MRID 46246501

Freundlich soil-water 

partition coefficients 

(KF)

(mL/g) LS SCL SL S

Prothioconazole -- -- -- -- Same as for KOC. MRID’s 46246539 

46246504

Prothioconazole

-desthio 4.13 8.90 12.46

13.3

8

Same as for KOC. MRID 46246450

Prothioconazole

-S-methyl 15.6 41.2 56.0 64.1

Same as for KOC. MRID 46246501

Field Dissipation

Terrestrial field 

dissipation (half-life in 

surface soil; leaching 

depth)

California (sandy loam/loam): 

Prothioconazole: 

2.2 days; 

Not detected above LOD below a depth 

of 15 cm nor after 7 DAT. 

Prothioconazole-desthio: 

84.5 days;

Detected above LOD to a depth of 45 cm 

and through 307 DAT.

For degradate half-lives, 

the day of maximum 

concentration of the 

degradate was used as day 

zero in the regression.

46246517
11

Parameter Value Description/Comments Source

Georgia (sand/sandy loam): 

Prothioconazole: 

4.7 days; 

Not detected above detection limit 

(LOD) below a depth of 15 cm nor after 

14 days after treatment (DAT).

Prothioconazole-desthio:

96.3 days; 

Detected above LOD to a depth of 30 cm 

through 7 DAT. 

For degradate half-lives, 

the day of maximum 

concentration of the 

degradate was used as day 

zero in the regression.

46246518

New York (loamy sand):

Prothioconazole:

96.3 days; 

Not detected above LOD below a depth 

of 15 cm nor after 211 DAT.

Prothioconazole-desthio: 

315.1 days; 

Not detected above LOD below a depth 

of 15 cm (except for one sampling 

interval (211 DAT) where detected 

above LOD to 30 cm); detected above 

LOD through study completion (567 

DAT).

For degradate half-lives, 

the day of maximum 

concentration of the 

degradate was used as day 

zero in the regression.

46246519

Aquatic field 

dissipation (half-life) 

California (clay): 

Prothioconazole: 

203.9 days (in sediment); 

1.7 days (in paddy water) 

Prothioconazole-desthio: 

122 days (in sediment)

For degradate half-lives, 

the day of maximum 

concentration of the 

degradate was used as day 

zero in the regression.

46246522 

Arkansas (loam): 

Prothioconazole: 

too few detections in sediment; 

4.8 days (in paddy water)

Prothioconazole-desthio: 

121.6 days(in sediment)

For degradate half-lives, 

the day of maximum 

concentration of the 

degradate was used as day 

zero in the regression.

46246523 

Arkansas-cropped (loam): 

Prothioconazole: 

too few detections in sediment; 

0.6 days (in paddy water) 

Prothioconazole-desthio: 

90.0 days (in sediment)

For degradate half-lives, 

the day of maximum 

concentration of the 

degradate was used as day 

zero in the regression.

46246524

Fish Bioconcentration
12

Parameter Value Description/Comments Source

Fish bioconcentration 

factors (steady-state); 

depuration rate

Prothioconazole and prothioconazoledesthio do not appear to bioaccumulate. 

BCF could not be 

calculated due to lack of a 

clear accumulation plateau.

46246034 

46246035

Unextracted residues were observed at maximums of 38.2-56.4% of the applied 

radioactivity across both soils and both labels by the end (365 d) of an aerobic soil metabolism 

study (MRID 46246511) in which samples were only extracted once with acetonitrile/water. 

Unextracted residues were also high in other studies, at 46.7% of the applied in an aerobic 

aquatic metabolism study (MRID 46246515, triazole label, 121DAT) and 26.5% in an anaerobic 

aquatic metabolism study (MRID 46246516, phenyl label, 360DAT). Residue extraction was 

attempted by extracting with a relatively mild acetonitrile/water solution (80:20, v:v for aerobic 

soil metabolism, 90:10, v:v for aerobic aquatic metabolism, 80:20 or 70:30, v:v for anaerobic 

aquatic metabolism) on a mechanical shaker followed by hot extraction by reflux for all studies 

involving soil. Additionally, some aerobic aquatic metabolism study sediment samples were 

extracted further with acetone/concentrated HCl (99:1, v:v). It is uncertain whether or not 

greater amounts of soil-bound material could have been extracted using more appropriate 

methods (see guidance at http://www2.epa.gov/pesticide-science-and-assessing-pesticiderisks/guidance-addressing-unextracted-pesticide-residues). Because high levels of unextracted 

material in laboratory metabolism studies precluded accurate determinations of the biotic 

degradation rates for parent prothioconazole, a total toxic residues (TTR) method, including 

unextracted material, was utilized in past assessments for environmental exposure modeling. 

Additional details on this, and on the environmental fate and transport of prothioconazole and its

degradates can be found in the June 1, 2006 Ecological Risk Assessment (USEPA, 2006d). 

Because of this uncertainty associated with soil extraction, unextracted residues will be included

in the ecological risk assessment for Registration Review unless new data clearly indicate that 

the unextracted residues are not the parent compound or can be considered bound residues under 

current policy (USEPA 2014b).

a. Transformation Products

The major organic degradates of prothioconazole in submitted environmental fate studies 

were prothioconazole-desthio (SXX0665), prothioconazole-S-methyl (WAK7861-S-methyl), 

prothioconazole-thiazocine (JAU6476-thiazocine), and 1,2,4-triazole. Prothioconazole-desthio is 

formed quickly and in large amounts (up to 56% of applied) from all degradation processes 

evaluated. It is the result of desulfonation of prothioconazole parent. Prothioconazole-S-methyl 

is also formed in large amounts from anaerobic aquatic metabolism (78% of applied), and in 

lesser amounts from aerobic soil metabolism and aerobic aquatic metabolism. It is the result of 

methylation of the sulfur of prothioconazole parent. Both of these identified major 

transformation products are expected to form in large relative proportions in both terrestrial and 

aquatic environment compartments. Based on submitted toxicity studies, prothioconazoledesthio and prothioconazole-S-methyl are expected to exhibit similar toxicity to parent 

prothioconazole. Therefore, since these degradates are expected to form in high relative amounts

and are considered toxic, both prothioconazole-desthio and prothioconazole-S-methyl will be 

considered in the drinking water and ecological risk assessments as part of a total toxic residue 
13

approach. The degradate 1,2,4-triazole was a major degradate only in the aqueous photolysis 

(11.9%) and aerobic aquatic metabolism studies (maximum of 41.8%); in aerobic soil 

metabolism studies, it was only detected at <2% of the applied. Although it was not monitored 

in some studies which utilized only a phenyl radiolabel, the parent compound was essentially 

stable or showed minimal degradation in those studies. Based on submitted toxicity data for 

1,2,4-triazole, this degradate appears to be less toxic than the parent compound to all taxa with 

the exception of birds. Table summarizes the major transformation products of prothioconazole

and their maximum amounts formed.

Prothioconazole-thiazocine is formed at a maximum of 14.1% of applied radioactivity 

from aqueous photolysis only. This mode of degradation is only likely to be influential in clear, 

shallow water, under clear atmospheric conditions. In actual environmental systems, aqueous 

photolysis is likely to proceed at a much slower rate and the degradate is likely to form only in 

small amounts under very specific circumstances in the environment. Thus, the Health Effects 

Division (HED) has very low concern regarding the hazard associated with this compound, and 

prothioconazole-thiazocine will not be considered in the drinking water assessment (USEPA, 

2006c). 

A variety of minor degradates were also observed in the soil photolysis and/or in the soil 

and aquatic metabolism studies. The identified minor transformation products of

prothioconazole include: prothioconazole-sulfonic acid (JAU6726), prothioconazole-triazolinone 

(WAK7860), prothioconazole-3, 4, 5, and 6-hydroxy-desthio (3, 4, 5, and 6-HO-SXX0665), 2-

chlorobenzoic acid, and JAU6476-triazolylketone (WAK4995). Additional information on both 

the major and minor transformation products may be found in USEPA, 2006d.
14

Table 3. Prothioconazole and Its Major Environmental Degradates.

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type Ref.

(MRID)

Maximum 

%AR (day)A

Final %AR 

(study 

length)

PARENT

Prothioconazole

2-(2-(1-

chlorocylocpropyl)-3-

(2-chlorophenyl)-2-

hydroxy-propyl)-2,4-

dihydro(1,2,4)-triazol-3-

thion 

CAS No.: 178928-70-6

SMILES Code: 

C1C1(C(Cc2ccccc2C1)(

CN2N=CNC2=S)O)CC 

1

MW: 344.26 g/mol

MAJOR TRANSFORMATION PRODUCTS

Prothioconazole-desthio: 

2-[2-(1-

Chlorocyclopropyl)-3-

(2-chlorophenyl)-2-

hydroxy-propyl]-1,2-

dihydro-3H-1,2,4-

triazole

MW: 312.2 g/mol

Hydrolysis 46246505 5.2% (168 hr) 5.2% (168 hr)

Aq photolysis 46246507

54.8% (11 d; 

phenyl label)

55.7% (11 d; 

triazole label)

54.8% (18 d)

53.2% (18 d)

Soil photolysis 46246510

38.5% (7 d)

(25.4% at 7 days 

in dark control)

38.1% (15 d) 

(29.4% at 15 

days in dark 

control)
15

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type Ref.

(MRID)

Maximum 

%AR (day)A

Final %AR 

(study 

length)

Aerobic soil

(parent applied)

46246511, 

46246512

46.5-49.4% (7

d; both labels)

38.4-41.2% (90 

d; both labels)

41.3% (3 d)

20.9% (7 d)

6.1-6.3% (365

d)

21.9-23.7% 

(365 d)

42.3% (120 d)

18.5% (120 d)

Aerobic soil 

(desthio applied) 46246513 80-89% (0 d) 2.3-19.6% (120 d)

Aerobic aquatic 46246515

26.9% (14 d; in 

sediment, both 

labels)

32.3% (7 d; in 

water, phenyl 

label)

54.6% (7 d; in 

total system, 

phenyl label)

nd – 1.2% (121 

d; water, both 

labels) 

7.1-11.1% (121

d; sediment, 

both labels)

8.2-11.1% (121 

d; total system, 

both labels)

Anaerobic 

aquatic 46246516

Not determined; 

-desthio 

formation 

determined to be 

artifact of 

storage and, 

therefore, added 

to parent 

(parent+desthio 

at 95.2% in total 

system at 0 

days)

1.4% (360 d)
16

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type Ref.

(MRID)

Maximum 

%AR (day)A

Final %AR 

(study 

length)

TFD (CA) 46246517 191.0 ug/kg soil (3 d, 0-15 cm) 2.2 ug/kg soil 

(553 d)

TFD (GA) 46246518 82.0 ug/kg soil 

(0 d, 0-15cm)

ND-3.0 ug/kg 

soil (421-532

d)

TFD (NY) 46246519 221.0 ug/kg soil 

(58 d, 0-15cm)

82.5 ug/kg soil 

(567 d)

AFD

46246522, 

46246523, 

46246524

CA: 32.7 ug/kg 

sediment (14 d, 

0-3 in); 50.3 

ug/L paddy 

water (3 d)

AK: 63.2 ug/kg 

sediment (3 d, 

0-3 in); 109.8

ug/L paddy 

water (0 d)

CA: 20.4 ug/kg 

sediment (364 

d, 0-3 in); 0.69 

ug/L paddy 

water (60 d)

AK:4.4 ug/kg 

sediment (365

d, 0-3 in); 0.8

ug/L paddy 

water (60 d)

Prothioconazole-S-methyl: 

alpha-1(1-

chlorocyclopropyl)-

alpha-[(2-

chlorophenyl)methyl]-3-

(methylthio)-1H-1,2,4-

triazole-1-ethanol

MW: 358.3 g/mol

Aerobic soil

(parent applied)

46246511, 

46246512

11.3-12.8% (1

d; both labels)

13.7-14.6% (7 

d; both labels)

3.8-5.5% (1-7 d)

2.8-3.1% (365

d)

7.1-7.6% (365 

d)

1.5-1.7% (7d)

Aerobic soil (Smethyl applied) 46246514 77-80% (0 d) 2.4-17.2% (125 

d)

Aerobic aquatic 46246515

9.6% (7 d; in 

sediment, 

triazole label)

nd (121 d; 

water, both 

labels)
17

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type Ref.

(MRID)

Maximum 

%AR (day)A

Final %AR 

(study 

length)

3.1% (7 d; in 

water, triazole

label)

12.7% (7 d; in 

total system, 

triazole label)

1.9-3.1% (121 

d; sediment 

and total 

system, both 

labels)

Anaerobic 

aquatic 46246516

78.2% (240 d; in 

sediment)

9.9% (30 d; in 

water)

78.2% (240 d; in 

total system)

<0.2% (360 d; 

water) 

76.1% (360 d; 

sediment and 

total system)

TFD (CA) 46246517 14.2 ug/kg soil (3 d, 0-15 cm) 1.9 ug/kg soil 

(63 d)

TFD (GA) 46246518 10.1 ug/kg soil 

(7 d, 0-15cm)

ND-1.3 ug/kg 

soil (120-141 

d)

TFD (NY) 46246519 46.9 ug/kg soil 

(7 d, 0-15cm)

4.0 ug/kg soil

(567 d)

AFD (CA)

46246522, 

46246523, 

46246524

CA: 10.0 ug/kg 

sediment (122 d, 

0-3 in); 0.23

ug/L paddy 

water (3 d)

AK: 16.7 ug/kg 

sediment (14 d, 

0-3 in); 3.0 ug/L 

paddy water (1

d)

CA: 5.3 ug/kg 

sediment (364

d, 0-3 in); 0.02

ug/L paddy 

water (28 d)

AK: ND

sediment (365

d, 0-3 in); 0.1 

ug/L paddy 

water (7-14 d)
18

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type Ref.

(MRID)

Maximum 

%AR (day)A

Final %AR 

(study 

length)

1,2,4-triazole

Aq photolysis 46246507 11.9% (18 d; 

triazole label) 11.9% (18 d)

Aerobic soil 46246511, 

46246512

<2.0% (120, 

272, & 365 d; 

(triazole label)

nd - <2% (365

d)

Aerobic aquatic 46246515

6.1% (121 d; in 

sediment, 

triazole label)

37.2% (121 d; in 

water, triazole 

label)

41.8% (121 d; in 

total system, 

triazole label)

6.1% (121 d; in 

sediment, 

triazole label; 

one system)

37.2% (121 d; 

in water, 

triazole label; 

one system)

41.8% (121 d; 

in total system, 

triazole label)

TFD (CA) 46246517 7.3 ug/kg soil 

(29 d, 0-15 cm)

1.3 ug/kg soil 

(553 d, 30-45 

cm)

TFD (GA) 46246518 4.9 ug/kg soil 

(120 d, 0-15cm)

ND-4.5 ug/kg 

soil (532 d; 15-

30 cm)

TFD (NY) 46246519 3.3 ug/kg soil 

(422 d, 0-15cm)

ND-3.1 ug/kg 

soil (567 d; 0-

15 cm)

AFD (CA)

46246522, 

46246523, 

46246524

CA: 3.3 ug/kg 

sediment (273-

364 d, 0-3 in); 

CA: 3.3 ug/kg 

sediment (364 

d, 0-3 in); 0.3 

N

H

N

N
19

Code Name/ 

Synonym Chemical Name Chemical Structure Study Type Ref.

(MRID)

Maximum 

%AR (day)A

Final %AR 

(study 

length)

0.13 ug/L paddy 

water (7 d)

AK: 2.9 ug/kg 

sediment (270 d, 

0-3 in); 0.5 ug/L 

paddy water (1

d)

ug/L paddy 

water (3 d)

AK: 2.9 ug/kg 

sediment (365

d, 0-3 in); 0.3 

ug/L paddy 

water (3 d)

Prothioconazolethiazocine Aq photolysis 46246507

14.1% (5 d; 

phenyl label)

9.5% (11 d; 

triazole label)

8.4% (18 d)

9.1% (18 d)

Studies conducted with both phenyl and triazole radiolabels include: aerobic soil metabolism (MRID: 46246511 only), aerobic aquatic metabolism, and aqueous photolysis. All other studies are

conducted with phenyl radiolabel only (ie., hydrolysis, soil photolysis, other aerobic soil metabolism (MRID: 46246512 only), anaerobic aquatic metabolism). The 1,2,4-triazole degradate is not able 

to be detected in studies using the phenyl radiolabel. Field studies not radiolabelled. The only degradates tracked in field studies are: prothioconazole-desthio, prothioconazole-S-methyl, 

prothioconazole-thiazocine, and 1,2,4-triazole. Maximum concentrations in the field studies are determined after the 6th (CA, NY) or 2nd (GA) application. (DAT= days after 6th or 2nd treatment); 800 

ug/kg, 400 ug/kg, and 1000 ug/kg total prothioconazole applied in CA, GA, and NY, respectively.
20

6. Receptors

Based on the registered uses of prothioconazole, aquatic and terrestrial non-target organisms 

are likely to be exposed to the chemical and/or its degradates. Although incomplete, the toxicity 

profiles for prothioconazole, prothioconazole-desthio and prothioconazole-S-methyl indicate that 

prothioconazole and the degradate prothioconazole-desthio are characterized as being practically 

non-toxic to birds, mammals, and honeybees (Apis mellifera), and slightly-to-moderately toxic to 

fish on an acute exposure basis. Based on a limited set of aquatic toxicity data for 

prothioconazole-S-methyl, it appears to be equally toxic to fish and freshwater invertebrates 

compared to prothioconazole-desthio and prothioconazole on an acute exposure basis. Chronic 

aquatic toxicity data are not available for prothioconazole-S-methyl. The degradate 1,2,4-triazole 

is less toxic than the parent compound to the few taxa for which data are available, with the 

exception of birds (acute exposure). In contrast, the degradate prothioconazole-desthio is highly 

toxic to estuarine/marine invertebrates on an acute exposure basis. Data for prothioconazole and 

prothioconazole-desthio do not indicate that either compound bioconcentrates in fish.

Tables 4-8 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 prothioconazole, prothioconazole-desthio and prothioconazole-S-methyl. No 

toxicity data were submitted or identified in the open literature for other degradates. Table 4

provides a summary of the toxicity data for the parent compound, prothioconazole, for aquatic 

organisms. Table 5 provides a summary of the toxicity data for the degradate prothioconazoledesthio for aquatic organisms. Table 6 provides a summary of the toxicity data for the degradate 

prothioconazole-S-methyl for aquatic organisms. Table 7 provides a summary of the toxicity data 

for the parent compound, prothioconazole, for terrestrial organisms. Finally, Table 8 provides a 

summary of the available toxicity data for the degradate, prothioconazole-desthio, for terrestrial 

organisms. Finally, toxicity data for the 1,2,4-Triazole degradate is summarized in Tables 9 and 

10. 

A listing of all of the available toxicity studies for prothioconazole and degradates, including 

registrant-submitted studies are provided in Appendix B. 

a. Effects to Aquatic Organisms

Aquatic toxicity data for animals and plants exposed to prothioconazole and its degradates 

are summarized in Tables 4-6, respectively. 

For aquatic freshwater fish and invertebrates, prothioconazole and its degradates 

prothioconazole-desthio and prothioconazole-S-methyl are all moderately toxic on an acute 

exposure basis. For estuarine/marine invertebrates, the degradate prothioconazole-desthio is very 

highly toxic under acute exposure conditions. In contrast, prothioconazole (parent) and 

prothioconazole-S-methyl are moderately toxic to freshwater invertebrates.

It is likely that under the conditions of chronic aquatic toxicity tests, most of the 

prothioconazole parent compound degrades into prothioconazole-desthio and/or prothioconazoleS-methyl (see Section 5.a., Transformation Products). Therefore, many key chronic toxicity 
21

data on the parent compound are absent. However, important chronic aquatic toxicity data for the 

major degradate prothioconazole-desthio are available. Fewer chronic aquatic toxicity data are 

available for prothioconazole S-methyl. 

On a chronic exposure basis, prothioconazole-desthio results in reduced larval/juvenile 

survival, spawning frequency, and growth of fathead minnows (Pimephales promelas) and 

reduced offspring production in water fleas (Daphnia magna). Data are needed to better 

understand toxicity to sediment dwelling organisms.

Aquatic plants appear particularly sensitive to both the parent and prothioconazoledesthio. The freshwater aquatic plant duckweed (Lemna gibba) and estuarine/marine diatom 

(Skeletonema costatum) are very sensitive to the parent compound. Comparative aquatic plant 

data are not available for prothioconazole-desthio or prothioconazole-S-methyl. Given the high 

sensitivity of aquatic plants to prothioconazole-desthio, estuarine/marine aquatic plant data are 

warranted to inform a more comprehensive aquatic plant risk assessment.

Table 4. Prothioconazole: Toxicity Data for Aquatic Organisms

Taxonomic 

Group Study Type Surrogate Species

Toxicity Value

(all units in terms 

of measured 

active ingredient)

Acute 

Toxicity 

Classification

Source MRID; 

(Test 

Substance)

Study 

Classification

Freshwater 

Fish

96-Hour Acute 

Toxicity

Rainbow trout

(Oncorhynchus 

mykiss)

96-hr LC50=1.83 

mg a.i./L

Moderately 

Toxic

46246018

(TGAI) Acceptable

96-hr LC50=1.69 

mg a.i./L

Moderately 

Toxic

46246019

(TEP) Acceptable

Bluegill

(Lepomis 

macrochirus)

96-hr LC50=4.59 

mg a.i./L

Moderately 

Toxic

46246022 

(TGAI) Acceptable

96-hr LC50=5.53 

mg a.i./L

Moderately 

Toxic

46246023

(TEP, 41% a.i.) Acceptable

Common Carp

(Cyprinus carpio)

96-hr LC50=6.42 

mg a.i./L

Moderately 

Toxic

46246025

(TGAI) Supplemental

Bioconcentration 

and 

Biotransformation

Bluegill (Lepomis 

macrochirus)

Does not 

bioaccumulate in 

fish.

N/A 46246034 Supplemental

Freshwater 

Invertebrates

Acute Toxicity

Water Flea

(Daphnia magna)

EC50=1.20 mg 

a.i./L

Moderately 

Toxic

46246009

(TGAI) Acceptable

EC50=4.1 mg a.i./L Moderately 

Toxic

46246010

(TEP, 41% a.i.) Supplemental

Chronic Toxicity

NOAEC=0.51 mg 

a.i./L

(Reproduction, 

growth)

N/A 46246028

(TGAI) Acceptable

Midge

Chironomus 

riparius

NOAEC=0.985 mg 

a.i./L (pore water)

(Emergence)

N/A 46246131 Supplemental 
22

Taxonomic 

Group Study Type Surrogate Species

Toxicity Value

(all units in terms 

of measured 

active ingredient)

Acute 

Toxicity 

Classification

Source MRID; 

(Test 

Substance)

Study 

Classification

Estuarine/ 

Marine Fish

96-Hour Acute 

Toxicity Sheepshead 

minnow

Cyprinodon 

variegatus

LC50>10.3 mg 

a.i./L

Slightly Toxic 46246027

(TGAI) Acceptable

Early Life Stage 

Toxicity

(28-d)

No Data

Estuarine/ 

Marine 

Invertebrates

96-Hour Shell 

Deposition

Eastern oyster

Crassostrea 

virginica

EC50=3.0 mg a.i./L Moderately 

Toxic

46246014

(TGAI) Acceptable

Acute Toxicity

Mysid

Americamysis 

bahia (formerly

Mysidopsis 

bahia)

EC50=2.4 mg a.i./L Moderately 

Toxic

46246016

(TGAI)

Acceptable

Aquatic 

Plants

7-Day Toxicity Duckweed 

(Lemna gibba)

EC50=0.073 mg 

a.i./L

NOAEC=0.003 mg 

a.i./L

(Frond number)

N/A 46246101

(TGAI) Acceptable

EC50=0.110 mg

a.i./L

NOAEC=0.0075 

mg a.i./L

(Frond number)

N/A 46246102

(TEP, 41% a.i.) Acceptable

96-Hour Toxicity

Blue-green algae

(Anabaena flosaquae)

EC50=3.5 mg a.i./L

NOAEC=0.82 mg 

a.i./L 

(Cell density)

N/A 46246103

(TGAI) Acceptable

96-Hour Toxicity

Green Algae

(Selenestrum 

capricornutum)

EC50=0.88 mg 

a.i./L

NOAEC=0.371 mg 

a.i./L 

(Cell density)

N/A 46246105

(TGAI) Acceptable

Freshwater alga

(Pseudokirchneri

ella subcapitata)

(formerly

Selenastrum 

capricornutum)

EC50=1.1 mg a.i./L

NOAEC=0.48 mg 

a.i./L 

(Cell density)

N/A 46246106

(TEP) Acceptable
23

Taxonomic 

Group Study Type Surrogate Species

Toxicity Value

(all units in terms 

of measured 

active ingredient)

Acute 

Toxicity 

Classification

Source MRID; 

(Test 

Substance)

Study 

Classification

Aquatic 

Plants 96-Hour Toxicity

Freshwater 

Diatom (Navicula 

pelliculosa)

EC50=0.180 mg 

a.i./L

EC05=0.06 mg 

a.i./L

NOAEC: Not 

determined

(Biomass)

N/A 46246109

(TGAI) Acceptable

Estuarine/marine

Diatom 

(Skeletonema 

costatum)

EC50=0.021 mg 

a.i./L

NOAEC=0.0073 

mg a.i./L

(Biomass)

N/A

46246110

(TGAI) Acceptable

Table 5. Prothioconazole-Desthio: Toxicity Data for Aquatic Organisms

Taxonomic 

Group Study Type Species

Toxicity Value

(all units in terms 

of measured 

degradate)

Acute 

Toxicity 

Classification

Source 

(MRID) Study Classification

Freshwater 

Fish

96-Hour Acute 

Toxicity

Rainbow trout

(Oncorhynchus 

mykiss)

96-hr LC50=5.94 

mg/L

Moderately 

Toxic 46246020 Acceptable

Fathead Minnow 

(Pimephales 

promelas)

96-hr LC50=11.4 

mg/L Slightly Toxic 46246026 Acceptable

Full Life Cycle 

Toxicity

Fathead minnow

(Pimephales 

promelas)

NOAEC=0.148 

mg/L

LOAEC= 0.296 

mg/L

(Survival, spawning 

frequency, growth, 

deformities)

N/A 46246033 Supplemental

Freshwater 

Invertebrates Chronic Toxicity

Water Flea

(Daphnia magna)

NOAEC=0.103 

mg/L 

LOAEC= 0.206 

mg/L

(Offspring 

production)

N/A 46246029 Acceptable

Midge

(Chironomus 

riparius)

NOAEC=0.34 mg/L 

(pore water)

LOAEC=0.64 mg/L

(Emergence)

N/A 47626901 Supplemental

Estuarine/ 

Marine

Invertebrates

Acute Toxicity LC50=0.06 mg/L Very Highly 

Toxic 46246017 Acceptable
24

Taxonomic 

Group Study Type Species

Toxicity Value

(all units in terms 

of measured 

degradate)

Acute 

Toxicity 

Classification

Source 

(MRID) Study Classification

Chronic Toxicity

Mysid

(Americamysis 

bahia) (formerly

Mysidopsis 

bahia)

NOAEC=0.064 

mg/L 

LOAEC= 0.128 

mg/L

(Reproduction)

N/A 46246030 Acceptable

Estuarine/ 

Marine Fish

96-Hour Acute 

Toxicity No Data

Early Life Stage 

Toxicity (28-Day) No Data

Aquatic 

Plants

7-Day Study Duckweed

(Lemna gibba)

EC50=0.035 mg/L

NOAEC=0.0058 

mg/L

(Frond number)

N/A 46246104 Acceptable

96-Hour Toxicity

Green Algae

(Scenedesmus 

subspicatus)

EC50=0.074 mg/L

EC05=0.011 mg/L

NOAEC: Not 

determined (<0.011 

mg/L)

(Cell density)

46246010

N/A 46246108 Acceptable

Freshwater 

Fish

Bioconcentration 

and 

Biotransformation

Bluegill (Lepomis 

macrochirus)

Does not 

bioaccumulate in 

fish.

N/A 46246035 Acceptable

Table 6. Prothioconazole-S-Methyl: Summary of Toxicity Data for Aquatic Organisms

Taxonomic 

Group Study Type Species

Toxicity Value

(all units in terms 

of measured 

degradate)

Acute 

Toxicity 

Classification

Source 

(MRID) Study Classification

Freshwater 

Fish

Acute Toxicity

Rainbow trout

Oncorhynchus 

mykiss

96-hr LC50=1.78 

mg/L

Moderately 

Toxic 46246021 Acceptable

Full Life Cycle 

Toxicity

Fathead minnow

Pimephales 

promelas

No Data

Freshwater 

Invertebrates

Acute Toxicity Water Flea

(Daphnia magna) EC50=2.7 mg/L Moderately Toxic 46246012 Acceptable
25

Taxonomic 

Group Study Type Species

Toxicity Value

(all units in terms 

of measured 

degradate)

Acute 

Toxicity 

Classification

Source 

(MRID) Study Classification

Acute Toxicity Midge

Chironomus 

riparius

No Data

Chronic Effects on 

Midge Larvae

(28-d)

No Data

Estuarine/ 

Marine Fish

96-Hour Acute 

Toxicity

Sheepshead 

minnow

Cyprinodon 

variegatus

No Data

Aquatic 

Plants 96-Hour Toxicity

Green Algae

(Selenestrum 

capricornutum)

EC50=2.8 mg/L

NOAEC=Not 

determined

N/A 46246107 Supplemental

b. Effects to Terrestrial Organisms

Toxicity values for terrestrial animals and plants are summarized in Tables 7 and 8, 

respectively.

Prothioconazole and its degradate prothioconazole-desthio are, for the most part, 

practically non-toxic to mammals and birds under acute exposure conditions. Prothioconazole is 

practically non-toxic to adult honey bees on an acute exposure basis. Acute toxicity data for 

honey bees are lacking for prothioconazole-desthio. There are no terrestrial ecotoxicity data for 

prothioconazole-S-methyl (degradate). 

In general, prothioconazole-desthio appears to be more toxic to terrestrial organisms than 

the parent compound. In birds, 70% mortality was observed in bobwhite quail in the acute dietary 

study involving exposure to prothioconazole-desthio at the highest exposure level, and the 

compound is classified as slightly toxic to birds on an acute exposure basis. Sub-lethal effects 

including decreased body weight and clinical toxicity were observed in the acute avian oral and 

dietary studies with prothioconazole-desthio. In chronic avian studies, no significant effects of the 

parent or degradates were reported at concentrations up to 449 mg/kg. In chronic mammalian 

tests on prothioconazole-desthio, reproductive effects including decreased pup viability and 

decreased pup weight were observed at a LOAEL of 640 mg/kg-diet with a corresponding 

NOAEL of 160 mg/kg-diet. The NOAEL is equivalent to a dose of 9.5 mg/kg bw/day in female 

rats. 

Tier I plant studies were conducted with 10 species of plants exposed to 0.272 lbs a.i./A, 

which is greater than the maximum single application rate of 0.178 lbs a.i./A. With the exception 

of cucumbers, effects did not exceed 25% inhibition. For cucumber plants, there was a greater 
26

than 25% effect on shoot length and dry weight in the seedling emergence study. Although 

effects in cucumbers did not exceed 25% in the vegetative vigor study, the percent inhibition for 

this species was generally among the highest. Based on the results of the Tier I study, a Tier II 

study for cucumber was required.

In the Tier II seedling emergence study, no effects exceeded a 25% inhibition compared to 

control for cucumbers for the highest test concentration of 0.272 lbs a.i./A. However, there were 

significant effects on both shoot height and dry weight with the lowest NOAEC associated with 

shoot height. The NOAEC and EC05 for shoot height are equivalent to application rates of 0.03 

and 0.08 lbs a.i./A, respectively; the NOAEC is used to calculate RQs for listed plants while the 

EC25 is used for non-listed plants. 

Table 7. Prothioconazole: Toxicity Data for Terrestrial Organisms

Taxonomic 

Group Study Type Surrogate Species

Toxicity Value

(all units in terms 

of measured active 

ingredient)

Acute 

Toxicity 

Classification

Source 

MRID; 

(Test 

Substance)

Study Classification

Birds

Acute Toxicity

Bobwhite Quail 

(Colinus 

virginianus)

LD50>2000 mg 

a.i./kg bw

Practically 

Non-Toxic

46246036

(TGAI) Acceptable

Canary (Serinus 

canaria)

LD50>2000 mg

a.i./kg-bw

Practically 

Non-Toxic

48024801

(TGAI) Acceptable

Sub-Acute 

Toxicity

Bobwhite Quail 

(Colinus 

virginianus)

LC50>4983 mg 

a.i./kg-diet

Practically 

non-toxic

46246038

(TGAI) Acceptable

Mallard Duck 

(Anas 

platyrhynchus)

LC50>5567 mg 

a.i./kg-diet

Practically 

non-toxic

46246040

(TGAI) Acceptable

Reproduction 

Toxicity

Bobwhite Quail 

(Colinus 

virginianus)

NOAEC=982 mg 

a.i./kg-diet

(LOAEC>982 mg 

a.i./kg-diet)

N/A 46246042

(TGAI) Acceptable

Mallard Duck

(Anas 

platyrhynchus)

NOAEC=1978 mg 

a.i./kg-diet

(LOAEC>1978 mg 

a.i./kg-diet)

N/A 46246044

(TGAI) Acceptable

Mammals

Acute Oral 

Toxicity

Norway Rat

(Rattus 

norvegicus)

LD50≥6200 mg/kg Practically 

Non-Toxic 46246230 Acceptable

Acute Inhalation 

Toxicity LC50 ≥ 4.99 mg/L Toxicity Category 4 46246246 Acceptable

2-Generation 

Mammal 

Reproduction 

Toxicity

NOAEL=100 mg 

a.i./kg/day

LOAEC=750 mg 

a.i./kg/day

(decreased number 

and duration of 

estrus cycles)

N/A 46246334 Acceptable

Terrestrial 

Invertebrates

Acute Adult 

Honey Bee 

Contact Toxicity

Honey bee 

(Apis mellifera)

LD50>200 μg

a.i./bee

Practically 

Non-Toxic

46246046

(TEP) Acceptable

Acute Oral 

Toxicity

LD50>232 μg

a.i./bee

Acute Contact 

Toxicity

LD50>200 μg 

a.i./bee 46246048 

(TGAI)

Acceptable

Acute Oral 

Toxicity LD50>71 μg a.i./bee Practically Non-Toxic Supplemental
27

Taxonomic 

Group Study Type Surrogate Species

Toxicity Value

(all units in terms 

of measured active 

ingredient)

Acute 

Toxicity 

Classification

Source 

MRID; 

(Test 

Substance)

Study Classification

Terrestrial 

Plants

Tier 1 Seedling 

Emergence

Buckwheat, Corn, 

Onion, Ryegrass, 

Wheat, 

Cucumber, 

Soybean, 

Sunflower, 

Tomato, Turnip

EC25>0.272 lb a.i./A

NOAEC=0.272 lb 

a.i./A

[Except: Cucumber; 

EC25<0.272 lb 

a.i./A; 

NOAEC=<0.272 lb 

a.i./A)]

N/A

46246049

(TEP, 41% 

a.i.)

Acceptable

Tier 1 Vegetative 

Vigor N/A Acceptable

Tier 2 Seedling 

Emergence Cucumber

NOAEC=0.03 lb 

a.i./A

EC25>0.272 lb a.i./A

(Shoot height)

N/A

46246050

(TEP, 41% 

a.i.))

Acceptable

Table 8. Prothioconazole-Desthio: Toxicity Data for Terrestrial Organisms

Taxonomic 

Group Study Type Surrogate Species

Toxicity Value

(all units in terms 

of measured 

degradate)

Acute 

Toxicity 

Classification

Source 

MRID; 

(Test 

Substance)

Study Classification

Birds

Acute Toxicity

Bobwhite Quail 

(Colinus 

virginianus)

LD50>2000 mg/kgbw

Practically 

Non-Toxic 46246037 Acceptable

Sub-Acute 

Toxicity

(8-Day study)

LC50=4252 mg/kgbw Slightly Toxic 46246039 Acceptable

Reproduction 

Toxicity

NOAEC=506.7

mg/kg-diet

LOAEC>506.7 

mg/kg-diet

N/A 46246043 Acceptable

Mallard Duck

(Anas 

platyrhynchus)

NOAEC=449 

mg/kg-diet

(LOAEC>449 

mg/kg-diet)

N/A 46246045

Supplemental

(Issues with degradation 

of test substance)

Mammals

Acute Oral 

Toxicity

Norway Rat

(Rattus 

norvegicus)

LD50=2806 mg/kg Practically 

Non-Toxic 46246231 Acceptable

Acute Inhalation 

Toxicity LC50 ≥ 5.08 mg/L Toxicity Category 4 46246247 Acceptable

2-Generation 

Mammal 

Reproduction 

Toxicity

NOAEL=10.4 

mg/kg/day

LOAEL= 42.6 

mg/kg/day

(decreased viability 

of pups)

N/A 46246333 Acceptable

Terrestrial 

Invertebrates

Acute Oral 

Toxicity Honey bee

(Apis mellifera) No Data Acute Contact 

Toxicity

Toxicity of Prothioconazole Degradate: 1,2,4-Triazole 

Available guideline data for the degradate of prothioconazole - 1,2,4-triazole (PC 600074) 

are presented in Table 9 and 10. To compare the toxicity of the degradate 1,2,4-triazole to the 
28

parent prothioconazole, a molecular weight conversion was completed to determine if 1,2,4-

triazole was more/less or equally as toxic to aquatic and terrestrial organisms as the parent 

prothioconazole. Based on the available toxicity data, 1,2,4-triazole is less toxic than 

prothioconazole to non-vascular plants (green algae), freshwater fish (acute basis), and freshwater 

invertebrates (acute basis). Birds however, appear to be more sensitive to 1,2,4-triazole compared 

to the parent prothioconazole. Finally, 1,2,4-triazole is less toxic than prothioconazole to 

mammals on a chronic exposure basis. However, there is uncertainty about the relative chronic 

toxicity to mammals for the two compounds because a NOAEC was established in the 

prothioconazole study (100 mg ai/kg-diet) whereas the 1,2,4-triazole study did not test below 250 

mg ai/kg-diet. Therefore, an accurate comparison to the toxicity of the parent and degradate 

cannot be completed.

The 1,2,4-triazole showed chronic effects to mammals at 250 mg ai/kg-diet (15 mg/kgbw); however, there is uncertainty about the relative chronic toxicity because a NOAEC was not 

established as the 1,2,4-triazole study did not test below 250 mg ai/kg-diet. Observed effects in 

adults included decreases in male body weight in F1 males, decreases in spleen weight in F1 

females, cerebellar lesions and decreases in brain and thyroid weight. Offspring effects included 

decreases in body weight, impacts on brain weight in F2 pups, and decreased spleen weight in F2 

female pups. Reproductive effects were also noted and included abnormal sperm and decreases in 

the number of corpora lutea in F1 females, reproductive failure (no viable offspring, and increases 

in corpora lutea in F0 parental females). 

Non-guideline, summary report data on acute oral toxicity to rats suggests that 1,2,4-

triazole (LD50s ranging from 1375 to 3080 mg/kg bw) and prothioconazole (LD50 > 6200 mg 

ai/kg bw) are practically non-toxic on an acute exposure basis.

Table 9. Summary of Aquatic Toxicity Data for Prothioconazole Degradate 1,2,4-Triazole

Type of Study Species Toxicity Value MRID #

Acute – Freshwater Fish Rainbow trout

(S. gairdneri)

96-hr LC50 = 498 mg a.i./L1 

(2483 mg a.i./L)

2 (practically non-toxic) 48474301

Acute – Freshwater Invertebrate Water flea 

(D. magna)

48-hr EC50 > 98.1 mg a.i./L1 (>489 mg a.i./L)

2 

(practically non-toxic) 48453206

Non-vascular Aquatic Plant Freshwater Algae

(P. subcapitata)

96-hr EC50 = 14 mg a.i./L1 

(69.8 mg a.i./L)2 45880401

1 Expressed in terms of 1,2,4-triazole 2 Expressed in terms of prothioconazole – A conversion is made from 1,2,4-triazole to prothioconazole on a molecular 

weight basis. Multiply 1,2,4-triazole toxicity endpoint (e.g., LD50 value) by the ratio of the molecular weight of 

prothioconazole divided by the molecular weight 1,2,4-triazole (344.3 g/mol/69.0635 g/mol = 4.985). 

Table 10. Summary of Terrestrial Toxicity Data for Prothioconazole Degradate 1,2,4-

Triazole

Type of Study Species Toxicity Value MRID #

Acute – Avian Oral Dose Bobwhite quail

(C. virginianus)

LD50 = 770 mg ai/kg-bw1 

(slightly toxic)

(3839 mg ai/kg-bw)2

(practically non-toxic)

49380701

Two Generation 

Reproduction – Mammalian

Laboratory rat

(R. norvegicus)

NOAEC < 250 mg ai/kg-diet1

LOAEC ≤ 250 mg ai/kg-diet1

(<1246 mg ai/kg-diet)2

Most sensitive effects were decreased bodyweight 

and decreased bodyweight gain in the parents and 

in the offspring.

46467304
29

Type of Study Species Toxicity Value MRID #

Subchronic 

(28 day adult) and 

reproductive (additional 28 

day offspring) – Terrestrial 

Invertebrate

Earthworm 

(E. fetida)

LC50 > 0.07081 mg/kg1

(> 0.3530 mg/kg)2

NOAEC ≥ 0.07081 mg/kg1

(≥0.3530 mg/kg)2

LOAEC > 0.07081 mg/kg

No significant effects observed (mortality, 

behavior, bw, reproduction or food consumption in 

any trmt group)

45880402

28 day – Terrestrial 

Invertebrate 

Springtails

(Folsomia candida)

28-day LC50 > 10 mg ai/kg soil1

(>49.85 mg ai/kg soil)2

NOAEC = 1.8 mg ai/kg soil

(8.973 mg ai/kg soil)2

LOAEC = 3.2 mg ai/kg soil 

based on reduced number of juveniles

45880404

1 Expressed in terms of 1,2,4-triazole 2 Expressed in terms of prothioconazole – A conversion is made from 1,2,4-triazole to prothioconazole on a molecular 

weight basis. Multiply 1,2,4-triazole toxicity endpoint (e.g., LD50 value) by the ratio of the molecular weight of 

prothioconazole divided by the molecular weight 1,2,4-triazole (344.3 g/mol/69.0635 g/mol = 4.985). 

c. Ecological Incidents

During the risk assessment process, the risk assessor will incorporate information from 

ecological incident reports by searching the most recent information available. Databases that 

will be queried include the Ecological Incident Information System (EIIS), the Avian Monitoring 

System (AIMS) and the OPP Aggregate Incident Database (IDS). EIIS is an OPP database that 

houses ecological incidents that have been reported to the Agency. When available, EIIS includes 

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

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

residue analysis or other analyses conducted during incident investigation. EIIS incidents are 

categorized according to the certainty that the incident resulted from pesticide exposure. AIMS is 

a database administered by the American Bird Conservancy that contains publicly available data 

on reported avian incidents involving pesticides. The Aggregate Incident Reports database is an 

Agency database that may contain minor wildlife and plant incidents for chemicals. Based on a 

search conducted August 12, 2015, there were no reported incidents for prothioconazole in the 

AIMS database. 

As of August 27, 2015, EIIS contains a total of 15 plant incidents for prothioconazole. No 

reports were found for the degradates 1,2,4-triazole, prothioconazole-desthio or prothioconazoleS-methyl. For prothioconazole (parent compound), plant damage was reported most often in 

peanuts, but was also reported in corn, soybean, wheat, sorghum and general agricultural areas in 

Georgia, Minnesota, Illinois, Iowa, Florida and North Dakota. All were classified as “possible” 

certainty. See Appendix C for a summary table of the incidents from EIIS.

OPP's IDS includes reports of pesticide incidents from various sources, including

mandatory Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) Section 6(a)(2) reports

from registrants, other federal and state health and environmental agencies, and individual

consumers. Since 1992, OPP has compiled these reports in IDS. IDS contains reports from across 

the U.S. and most incidents have all relevant product information recorded. This system stores 

incident data and includes information about the location, date and nature of the incident. IDS was 
30

searched August 12, 2015 and returned 8 total ecological incident reports between 1997 and 2013. 

These were reports for minor plant damage caused by prothioconazole,

The lack of reported incidences should not be construed as the absence of incidents. 

Incident reports for non-target organisms typically provide information only on mortality events 

and plant damage. Sublethal effects in organisms such as abnormal behavior, reduced growth 

and/or impaired reproduction are rarely reported, except for phytotoxic effects in terrestrial plants. 

7. Exposure Pathways of Concern

The environmental fate properties and use patterns of prothioconazole indicate that there 

are multiple potential transport mechanisms of prothioconazole and its degradates to aquatic and 

terrestrial organisms. 

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in the 

environment from a source to an ecological receptor. For an ecological pathway to be complete, it 

must include a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure.

The environmental fate properties of prothioconazole and its degradates indicate the following 

transport mechanisms for potential exposure to aquatic (including those dwelling in sediment) and 

terrestrial organisms:

• Direct contact 

• Spray drift

• Runoff

• Leaching to groundwater

• Consumption of contaminated food (sprayed food or treated seeds)

• Consumption of contaminated water

• Root uptake (plants)

• Exposure to sediment

• Irrigation water 

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

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

For the parent compound, prothioconazole, drinking water alone was found to be a 

potential concern for birds on both an acute and chronic exposure basis (no concern for 

mammals). For the degradate prothioconazole-desthio, drinking water alone is a concern for birds 

(both acute and chronic exposure basis) and mammals (chronic exposure basis only). Results for 

those pathways that result in risks of concern are displayed below in Tables 11 and 12.

However, inhalation exposure was found to be an exposure pathway of low concern for 

the parent compound (prothioconazole), as well as the prothioconazole-desthio and 1,2,4-triazole

degradates for both mammals and birds (no LOC exceedances are expected). See Appendices D
31

and E for example SIP and STIR results. SIP and STIR are described in detail at: 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm.

Table 11. SIP Results for Prothioconazole (Parent Compound)

Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 278.6400 278.6400

Adjusted toxicity value (mg/kg-bw) 1440.8590 48.7195

Ratio of exposure to acute toxicity 0.1934 5.7193

Conclusion*

Exposure through drinking 

water alone is a potential 

concern for birds

Exposure through drinking 

water alone is a potential 

concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when 

aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to 

a total exposure that has potential for effects to non-target animals.

Table 12. SIP Results for Prothioconazole-Desthio (Degradate)

Mammal Results

Parameter Acute Chronic

Upper bound exposure 

(mg/kg-bw) 59.1680 59.1680

Adjusted toxicity value 

(mg/kg-bw) 2158.2646 7.9993

Ratio of exposure to toxicity 0.0274 7.3967

Conclusion* Drinking water exposure alone is NOT 

a potential concern for mammals

Exposure through drinking water 

alone is a potential concern for 

mammals

Avian Results

Parameter Acute Chronic

Upper bound exposure 

(mg/kg-bw) 278.6400 278.6400

Adjusted toxicity value 

(mg/kg-bw) 1440.8590 25.1040

Ratio of exposure to acute 

toxicity 0.1934 11.0994

Conclusion* Exposure through drinking water 

alone is a potential concern for birds

Exposure through drinking water 

alone is a potential concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when 

aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may 

contribute to a total exposure that has potential for effects to non-target animals.
32

8. Analysis Plan

a. Stressors of Concern

i. Ecological Risk Assessment

The stressors of ecological concern for terrestrial and aquatic organisms are 

prothioconazole and two of the major degradates, prothioconazole-desthio and prothioconazole-Smethyl including the 1,2,4-triazole degradate and unextracted material. Because a TTR approach 

will be used to evaluate potential terrestrial and aquatic risks, the lowest (most sensitive) available 

toxicity value for each taxon will be used to calculate RQs. 

Using the TTR approach, risk will be calculated using the lowest or most sensitive toxicity 

value (most ecologically protective) available for either the parent prothioconazole compound, 

prothioconazole-desthio or prothioconazole-S-methyl. For example, in calculating acute RQs for 

aquatic invertebrates, exposure would be compared to the LC50 for prothioconazole-desthio, 

which has the lowest acute toxicity value (0.06 mg/L) for aquatic invertebrates.

Neither acute nor chronic toxicity data are available for prothioconazole-S-methyl for 

estuarine/marine fish and invertebrates. Acute estuarine/marine invertebrate data are requested for 

prothioconazole-S-methyl. More data are also needed to complete the toxicity profile for 

prothioconazole and prothioconazole-desthio. Specifically, sediment toxicity data are needed for 

prothioconazole and its degradates (See Section 11). In the absence of these data, risk will be 

presumed where there is exposure to non-target organisms. 

Although 1,2,4-triazole is a major degradate identified in the submitted aqueous photolysis 

(11%) and aerobic aquatic metabolism (41%) studies, it is only present at <2% in aerobic soil 

metabolism studies. Given the persistence of the TTR based on the parent and the two major 

degradates previously identified, the inclusion of 1,2,4-triazole is not expected to significantly 

alter the estimated exposure levels or impact risk. At this time it is anticipated that a separate risk 

assessment will be conducted on 1,2,4-triazole degradate, perhaps similar to the aggregate 

drinking water assessment completed for the triazole-derivative fungicides during the registration 

review process. The Office of Pesticide Program’s Health Effects Division (HED) has conducted 

aggregate human health risk assessments for 1,2,4-triazole and triazole conjugates, (USEPA 

2006b; D322215). However, an ecological risk assessment for 1,2,4-triazole has not been 

conducted as of this date. 

ii. Drinking Water 

The drinking water assessment (DWA) conducted to support the Registration Review 

human health risk assessments of prothioconazole will incorporate model estimates of 

prothioconazole residues of concern, which comprise parent compound (including unextracted 

residues, which may be parent), prothioconazole-desthio, and prothioconazole-S-methyl (USEPA, 

2006a; USEPA, 2012c), in surface water and groundwater. The prothioconazole residues of 

concern may be reevaluated pending receipt and review of additional environmental fate and 

toxicity data for prothioconazole and its degradates. The degradate 1,2-4 triazole is assessed 

separately because the compound has toxicity endpoints that are different from those of 
33

prothioconazole. In the absence of toxicity data, prothioconazole-desthio and prothioconazole-Smethyl are assumed to have similar toxicity to prothioconazole. Therefore, as in past EFED 

assessments, the EDWCs are based on TTR, i.e., the parent prothioconazole compound plus 

prothioconazole-desthio and prothioconazole-S-methyl including unextracted material, as 

discussed in USEPA, 2006c. It is anticipated that the DWA will be updated to include any new 

environmental fate data received by the Agency; specifically, it is anticipated that additional 

metabolism data will be used to amend modeling inputs. Additionally, the DWA will be updated 

using any new exposure models implemented since the last DWA was conducted.

b. Measures of Exposure

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

terrestrial organisms as described at http://www2.epa.gov/pesticide-science-and-assessingpesticide-risks/models-and-databases-used-pesticide-risk-assessment#models. 

Screening level calculations have suggested that drinking water may be a significant

exposure pathway for birds, although not for mammals. Inhalation exposure is not expected to 

represent a significant exposure pathway for either birds or mammals. These exposure pathways, 

and any others that are relevant may be further considered at the time of the risk assessment 

(Appendices C and D). 

Available Monitoring Data

No monitoring data for prothioconazole were identified. Neither the United States 

Geological Survey (USGS) NAWQA program nor the California Department of Pesticide 

Regulation (CDPR) include prothioconazole in their monitoring programs. 

c. Measures of Effect 

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

risk quotients. 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, 2009a), 

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.

9. 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 
34

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 (http://www2.epa.gov/endangered-species/implementingnas-report-recommendations-ecological-risk-assessment-endangered-and). EPA will address 

concerns specific to prothioconazole in connection with the development of its final Registration 

Review decision for prothioconazole.

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 (http://www2.epa.gov/endangered-species/interim-approachespesticide-endangered-species-act-assessments-based-nas-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 

prothioconazole 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 prothioconazole 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 prothioconazole as part of completing this Registration Review. 

10. Endocrine Disruptor Screening Program

Prothioconazole was not included in the first group of chemicals issued an order to 

conduct Tier 1 EDSP testing. For additional information the EDSP program, visit 

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

11. Preliminary Identification of Data Gaps 

a. Environmental Fate

Tables 13 and 14 identify 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.
35

Table 13. Environmental Fate Data for Prothioconazole.

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study

Classifications

Are data needed to 

conduct risk 

assessment?

Justification and 

Assumptions EPA will 

Make in Absence of Data - 

Some Example texts are 

include

835.2120 Hydrolysis 46246505 Acceptable No  ̄

835.2240 Aqueous 

photolysis 46246507 Supplemental No  ̄

835.2410 Soil photolysis 46246510 Acceptable No  ̄

835.4100 Aerobic soil 

metabolism

46246511

46246512 Acceptable

Yes, additional data are 

required for one more 

soil, with use of more 

appropriate/exhaustive 

extractions. Guidance is 

available1.

Without new useful 

information, unextracted 

residues will be added in as 

parent for the purposes of 

determining degradation rates 

for modeling.

835.4200 Anaerobic soil 

metabolism No data  ̄ No  ̄

835.4300 Aerobic aquatic 

metabolism 46246515 Supplemental No  ̄

835.4400

Anaerobic 

aquatic 

metabolism

46246516 Supplemental

Yes, additional data are 

required for one more

sediment/water system, 

with use of more

appropriate/ exhaustive 

extractions. Guidance is 

available1

.

Without new useful 

information, unextracted 

residues will be added in as 

parent for the purposes of 

determining degradation rates 

for modeling. Without 

additional data, for modeling, 

the single half-life value will 

be multiplied by 3 to account 

for uncertainty in using a 

single value.

835.1230

Adsorption/ 

desorption and 

leaching (batch 

EQ)

46246450 Acceptable

No  ̄

835.1240

Adsorption/ 

desorption and 

leaching (column 

leaching)

46246539

46246504 Supplemental

835.1410 Volatility –

laboratory No data No  ̄

835.6100

Terrestrial Field 

Dissipation

&

Analytical 

method in soil

46246517 Supplemental

No  ̄ 46246518 Supplemental

46246519 Supplemental

 1 http://www2.epa.gov/pesticide-science-and-assessing-pesticide-risks/guidance-addressing-unextracted-pesticide-residues.
36

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study

Classifications

Are data needed to 

conduct risk 

assessment?

Justification and 

Assumptions EPA will 

Make in Absence of Data - 

Some Example texts are 

include

835.6200

Aquatic field 

dissipation

&

Analytical 

method in water

46246522 Supplemental

No  ̄ 46246523 Supplemental

46246524 Supplemental

850.1730 Fish 

bioconcentration

46246034

46246035

Supplemental No  ̄

Table 14. Submitted Environmental Fate Data for the Prothioconazole Degradates, Prothioconazoledesthio and Prothioconazole-S-methyl

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions EPA 

will Make in Absence of Data

835.2120 Hydrolysis

(desthio) 46246506 Supplemental No  ̄

835.1230

Adsorption/ 

desorption

(desthio)

46246450 Acceptable No  ̄

835.1230

Adsorption/ 

desorption

(S-methyl)

46246501 Acceptable No  ̄

835.4100

Aerobic soil 

metabolism

(desthio)

46246513 Supplemental No  ̄

835.4100

Aerobic soil 

metabolism

(S-methyl)

46246514 Supplemental No  ̄

b. Ecological Effects

Tables 15 – 19 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. Justification for each data need is provided.

Table 15. Prothioconazole: Submitted Aquatic Ecological Effects Data

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and 

Assumptions EPA will Make 

in Absence of Data 

850.1010

Freshwater 

invertebrate

acute toxicity

46246009 Acceptable

No

46246010 Supplemental
37

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and 

Assumptions EPA will Make 

in Absence of Data 

850.1025

850.1035

850.1045

850.1055

Estuarine/marine

invertebrate

acute toxicity

46246016 Acceptable

No

46246014 Acceptable

850.1075 Freshwater fish 

acute toxicity

46246018 Acceptable

No

46246019 Acceptable

46246022 Acceptable

46246023 Acceptable

46246025 Supplemental

850.1075

Estuarine/marine

fish acute 

toxicity

46246027 Acceptable No

850.1300

Freshwater 

invertebrate

life cycle

46246028 Acceptable No

850.1350

Estuarine/marine

invertebrates

life cycle

No Data No

850.1400 Freshwater fish

early-life stage No Data No
38

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and 

Assumptions EPA will Make 

in Absence of Data 

850.1400

Estuarine/marine

fish

early-life stage

No Data No

850.1500 Fish life cycle No Data No

850.1735

Whole sediment: 

Chronic 

freshwater 

invertebrates

No Data

Yes, based on 

the physiochemical 

properties of 

prothioconazole, 

these data are 

required2,3

Test substance should be the 

prothioconazole TGAI. 

For freshwater sediment 

testing, tests on an amphipod 

(e.g., Hyalella azteca) and a 

midge (e.g., Chironomus 

dilutus) are requested. 

Results should be reported in 

terms of prothioconazole, 

prothioconazole-desthio and 

prothioconazole-S-methyl. A 

protocol must be submitted for 

review prior to initiating the 

studies.

In the absence of these data, 

EFED will make a presumption 

of risk to sediment-dwelling 

organisms.

850.1740

Whole sediment: 

Chronic marine 

invertebrates

No Data

Yes, based on 

the physiochemical 

properties of 

prothioconazole, 

these data are 

required2,4

Test substance should be the 

prothioconazole TGAI. 

For estuarine/marine sediment 

testing, tests on one amphipod 

species is requested (e.g., 

Leptocheirus plumulosus). 

Results should be reported in 

terms of prothioconazole, 

prothioconazole-desthio and 

prothioconazole-S-methyl. A 

protocol must be submitted for 

review prior to initiating the 

studies.

In the absence of these data, 

EFED will make a presumption 

of risk to sediment-dwelling 

organisms.

850.1790

Chironomid 

Sediment 

Toxicity

46246131 Supplemental No

850.4400 46246101 Acceptable No

 2 According to 40 CFR Part 158 Subpart G, pesticide sorption onto sediment particles is considered a trigger for sediment toxicity testing (i.e., 

moderate to high sorption as specified in Figure 1) if any of the following conditions exist: 1) The Kd is ≥ 50 L/kg-solid; 2) The KOC is ≥1000 

L/kg-organic carbon; 3) The log KOW is ≥ 3. 3,4 A tiered testing approach may be considered for requesting chronic sediment toxicity testing. Sediment toxicity testing would first be

conducted using the subchronic (10-d) sediment toxicity test guidelines (OSCPP 850.175 and 850.1740). Pending a comparison of estimated

environmental concentrations (EEC) in sediment and pore water with toxicity results from the 10-d sediment toxicity studies, the need for one or

more chronic sediment toxicity studies would be determined.
39

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and 

Assumptions EPA will Make 

in Absence of Data 

Aquatic plant 

Toxicity Test 

using Lemna 

spp.

46246102 Acceptable

850.4500 Algal toxicity

46246109 Acceptable

No

46246105 Acceptable

46246106 Acceptable

46246110 Acceptable

850.4550 Cyanobacteria 46246103 Acceptable No

Table 16. Prothioconazole-Desthio: Submitted Aquatic Ecological Effects Data

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions 

EPA will Make in Absence of 

Data

850.1010

Acute toxicity for

freshwater 

invertebrates

No Data Yes

This data is needed to fully 

characterize prothioconazoledesthio toxicity to freshwater 

invertebrates. 

850.1025

850.1035

850.1045

850.1055

Acute toxicity for 

estuarine/marine

invertebrates

46246017 Acceptable No

850.1075 Acute toxicity for 

freshwater fish

46246020 Acceptable

No

46246026 Acceptable

850.1075

Acute toxicity for 

estuarine/marine 

fish

No Data Yes

This data is needed to help 

understand toxicity to 

estuarine/marine fish.

850.1300

Chronic toxicity 

with freshwater 

invertebrates

46246029 Acceptable No

Chironomid 

Sediment 

Toxicity

47626901 Supplemental No

 
40

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions 

EPA will Make in Absence of 

Data

850.1350

Chronic toxicity 

estuarine/marine 

invertebrates

46246030 Acceptable No

850.1400

Fish Early Life 

Stage-Fresh water 

fish

No Data Yes

These data are needed to 

address the potential toxicity of 

prothioconazole-desthio to fresh 

water fish. It is recommended 

that test species be the most 

sensitive species indicated in the 

acute freshwater fish toxicity 

test (850.1075; Rainbow trout,

Oncorhynchus mykiss).

850.1400

Fish Early Life 

Stageestuarine/marine

fish 

No Data No

NonguidelineWhole sediment 

chronic toxicity

No Data No

850.1500 Fish life cycleFresh water fish 46246033 Supplemental No

850.1500

Fish life cycleestuarine/marine 

fish

No Data No

850.4500

Algal Toxicity 

Toxicity Test 

using Skeletonema 

costatum

No Data Yes

These data are needed to 

understand the potential toxicity 

of prothioconazole-desthio to 

non-vascular estuarine/marine 

diatoms (Skeletonema 

costatum).

850.4400

Aquatic plant 

Toxicity Test

using Lemna spp.

46246104 Acceptable No

850.4500 Algal toxicity 46246108 Acceptable No

NonGuideline

Bioaccumulation 

and 

Biotransformation

46246035 Acceptable No
41

Table 17. Prothioconazole-S-Methyl: Submitted Aquatic Ecological Effects Data

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions 

EPA will Make in Absence of 

Data

850.1010

Freshwater 

invertebrate

acute toxicity

46246012 Acceptable No

850.1025

850.1035

850.1045

850.1055

Acute toxicity to 

estuarine and 

marine 

invertebrates

No Data Yes

These data are required given 

that the parent compound 

degrades into prothioconazole-Smethyl in significant quantities in 

aquatic environments. These data

will help to fully characterize the 

toxicity of prothioconazole-Smethyl.

850.1075 Freshwater fish 

acute toxicity 46246021 Acceptable No

850.1075

Acute toxicity

estuarine/marine 

fish

No Data No

850.1300

Chronic toxicity

freshwater 

invertebrate

No Data No

850.1350

Aquatic 

invertebrate 

lifecycle 

(estuarine/marine)

No Data No

NonguidelineWhole sediment 

chronic toxicity

No Data No

850.1400

Fish early life 

stage 

(fresh water)

No Data No

850.4500 Algal toxicity 46246107 Supplemental No

Table 18. Prothioconazole: Submitted Terrestrial Ecological Effects Data

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Justification and 

Assumptions EPA will 

Make in Absence of Data

850.2100 Avian oral toxicity 46246036 Acceptable
42

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Justification and 

Assumptions EPA will 

Make in Absence of Data

48024801 Acceptable

Yes

(passerine 

species)

Acute avian oral toxicity 

data are required for 

passerine species. 

850.2200 Avian dietary 

toxicity

46246038 Acceptable

No

46246040 Acceptable

850.2300 Avian 

reproduction

46246042 Acceptable

No

46246044 Acceptable

870.1100 Mammal Acute 

Oral Toxicity 46246230 Acceptable No

870.1300 Acute inhalation 

rat

46246246 Acceptable No

870.3800

2-Generation 

Mammal 

Reproduction 

Toxicity

46246334 Acceptable No

850.3020

Honey bee adult 

acute contact 

toxicity (Tier I)

46246046 Acceptable

No

46246048 Acceptable

Honey bee adult 

acute oral toxicity 

(Tier I) (OECD 

Guideline 213)

46246046 Acceptable

No

46246048 Supplemental

Non-Guideline

Honey bee adult 

chronic oral 

toxicity (Tier I)

No Data Yes

These data are needed to 

fully characterize the 

toxicity to honey bees. A 

protocol should be 

submitted in advance of 

study initiation.

Special Study, 

OECD 237

Honey bee larvae 

acute oral toxicity

(Tier I)

No Data Yes

An acute oral toxicity 

study with honey bee 

larvae is needed.

Non-guideline

Honey bee larvae 

chronic toxicity

(Tier I)

No Data Yes

A repeat dose toxicity 

study with honey bee 

larvae is needed.

Non-guideline

Field trial of 

residues in pollen 

and nectar

(Tier II)

No Data Yes

Based on the use pattern, a

field trial measuring the 

residues of prothioconazole

in pollen and nectar is 

needed.

Special Study, 

OECD 75

Semi-field testing 

for pollinators No Data Tiered 

Approach

Results of the Tier I studies 

could trigger the higher 

Tier studies (Tier II and 

III), see above.
43

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Justification and 

Assumptions EPA will 

Make in Absence of Data

850.3040 Field testing for 

pollinators No Data Tiered 

approach

Results of the Tier I studies 

could trigger the higher 

Tier studies (Tier II and 

III), see above.

850.4100

Seedling 

Emergence and 

Seedling Growth, 

Tier 1

46246049 Acceptable No

Seedling 

Emergence and 

Seedling Growth, 

Tier 2

46246050 Acceptable No

850.4150

Vegetative Vigor, 

Tier 1 46246049 Acceptable No

Vegetative Vigor, 

Tier 2 No Data NA No

Table 19. Prothioconazole-Desthio: Submitted Terrestrial Ecological Effects Data

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Current Additional Data Need

850.2100 Avian oral 

toxicity 46246037 Acceptable

Yes

(passerine 

species)

Acute avian oral toxicity data are 

required for passerine species. 

850.2200 Avian dietary 

toxicity 46246039 Acceptable No

850.2300 Avian 

Reproduction

46246043 Acceptable

No

46246045 Supplemental

870.1100

Mammal 

Acute oral 

toxicity

46246231 Acceptable No

870.1300 Acute 

inhalation rat

46246247 Acceptable No

870.3800

2-Generation 

Mammal 

Reproduction 

Toxicity

46246333 Acceptable No
44

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Current Additional Data Need

850.3020

Honey bee 

acute contact 

toxicity

No Data NA Yes

These data are needed to fully 

characterize prothioconazole-desthio 

toxicity to honey bees. 

850.3020

Honey bee 

acute oral

toxicity

No Data NA Yes

These data are needed to fully 

characterize prothioconazole-desthio 

toxicity to honey bees. 

Data Gaps

Prothioconazole Parent Compound

• OCSPP 850.1735: Whole sediment acute toxicity for freshwater invertebrates (TGAI)

• OCSPP 850.1740: Whole sediment acute toxicity for estuarine/marine invertebrates

(TGAI)

• OCSPP 850.2100: Acute Oral Toxicity with passerine species (TGAI)

• OECD TG 237 and Non-guideline special studies: Honeybee larval acute and chronic 

oral toxicity studies (TGAI)

• Non-Guideline: Honey bee adult chronic oral toxicity test (TGAI)

• Special study OECD TG 75 and OSCPP 850.3040: Semi-field testing for pollinators (Tier 

II) and Field testing for pollinators (Tier III) (both studies that are conditionally required 

based on the results of the Tier I – laboratory based studies listed above; if needed these 

additional field studies will be discussed pending the results of the acute and chronic adult 

and larval oral toxicity studies to honey bees and/or Tier II studies (for the full field 

study); (TEP).

Prothioconazole-Desthio

• OCSPP 850.1010: Acute toxicity for freshwater invertebrates

• OCSPP 850.1075:Acute toxicity for estuarine/marine fish

• OCSPP 850.1400 Early life stage toxicity test with freshwater fish

• OCSPP 850.4500 Algal Toxicity with Non-vascular estuarine/marine diatom

• OCSPP 850.2100: Acute Oral Toxicity with avian passerine species

• OCSPP 850.3020: Honey Bee Acute Contact Toxicity

• OCSPP 850.3020 Honey Bee Acute Oral Toxicity

Prothioconazole-S-methyl

• OCSPP 850.1025, 850.1035, 850.1045, 850.1055: Acute toxicity to estuarine/marine 

invertebrates

Honeybee Toxicity

Although prothioconazole is categorized as practically non-toxic to adult honeybees on an 

acute contact exposure basis, and by extension, to other beneficial terrestrial invertebrates on an 

acute exposure basis, there is considerable uncertainty regarding the potential effects of the 

compound on honeybee larval development and survival as well as potential for chronic effects. 

Therefore, additional data on pollinators is needed to fully characterize the risk associated with 
45

prothioconazole use to all developmental stages of honeybees, as sensitivity may vary according 

to life-stage and length of exposure (adult vs. larval and acute vs. chronic, respectively). 

Additional information is needed, but uncertainty associated with risks to honey bees need to be 

evaluated with more data to different life stages. Prothioconazole is systemic in plants so 

exposure via pollen and nectar is possible; and therefore, residues of pollen and nectar of crops 

are an additional data need. Open literature data is needed to help better characterize some 

uncertainties regarding potential effects to bees and other non-target terrestrial invertebrates. In 

addition, higher tier effects toxicity tests (i.e., semi-field and/or field studies – Tier II and Tier III, 

respectively) may be needed, based on the results of the larval and chronic adult toxicity studies. 

Higher tier studies are recommended if the ratio of the EEC and larval or adult bee acute 

LD50>0.4 or the ratio of the EEC and the chronic NOAEC>1. Incident data and/or compelling 

open literature studies can also be used to support the need for higher tier studies. Should the 

screening level risk assessment identify that there are risk concerns to bees, mitigation measures 

may need to be considered or the registrant may need to conduct Tier II or Tier III effects studies 

(e.g. OECD Guideline 75 and/or 850.3040 guideline studies) that reduce uncertainty by 

characterizing prothioconazole’s effects at the whole-colony level4

.

 4 http://www2.epa.gov/pollinator-protection/pollinator-risk-assessment-guidance. 
46

Study Title: Honey bee Adult Acute Oral Toxicity

Rationale for Requiring the Data

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

eusocial bees, 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 honey bees and other insect 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 honey bees and other insect pollinators.

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

the honey bee as a surrogate test species. The guidances discusses Tier 1 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-assessment-guidance. Additional guidance on the 

honey bee oral toxicity test design can be found in OECD Test Guideline 213 (http://www.oecdilibrary.org/docserver/download/9721301e.pdf?expires=1423074617&id=id&accname=guest&checksum=

2F0764FCB4DCF01D32382952A2E995C3) 

Practical Utility of the Data

How will the data be used?

The Tier 1 acute oral toxicity data on adult honey bees serve as a foundation for the screening-level 

assessment of potential risk non-target organisms such as federally listed threatened or endangered and nonlisted 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 1 studies. If acute oral effects data for adult honey bees 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. 
47

Study Title: Honey bee Larvae Acute Oral Toxicity

Rationale for Requiring the Data

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

eusocial bees, pesticide residues may be transferred to pollen and/or nectar of treated plants and subsequently 

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

effects to developing bees 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 toxicity of this compound to bee brood. 

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

the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory-based acute toxicity 

studies of individual honey bee larvae as a critical component of the screening-level risk assessment process 

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

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

larval honey bee toxicity test design can be found in OECD Test Guideline 237 (http://www.oecdilibrary.org/docserver/download/9713171e.pdf?expires=1422485600&id=id&accname=guest&checksum=

D8E07C2B1DF77BF096C3B29F55BF86A7). In some cases, information pertaining to acute toxicity to 

honey bee larvae may be obtained with the chronic honey bee larval test thereby negating the need for 

separate acute and chronic larval toxicity tests.

Practical Utility of the Data

How will the data be used?

The Tier 1 acute toxicity data on honey 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 invertebrates, including pollinators, and/or modify their designated critical habitat from acute 

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

terrestrial invertebrates and will improve EPA’s understanding of the potential effects on terrestrial species 

and whether there is a differential sensitivity of larval bees relative to adult bees. If acute effects data for 

larvae are not available, risks to terrestrial insects from acute 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. 
48

Study Title: Honey Bee Adult Chronic Oral Toxicity

Rationale for Requiring the Data

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

eusocial bees, 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 honey bees 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 honey bees and other 

pollinators.

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

the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory-based chronic oral 

toxicity studies of individual adult honey bees 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. Although study

design elements for the chronic 10-day oral toxicity test with honey bees are similar to the OECD TG 213 

acute oral toxicity test ( http://www.oecdilibrary.org/docserver/download/9721301e.pdf?expires=1422484908&id=id&accname=guest&checksum=

C38495D2A570AC2216CFB1F223D24AA7), EPA requires that the proposed protocol for this study be 

submitted for review and approval by EPA prior to initiating the test.

Practical Utility of the Data

How will the data be used?

The Tier 1 chronic 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 nonlisted terrestrial invertebrates, 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 1 tests. If chronic oral effects data for adults are 

not available, risks to terrestrial insects from chronic 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. 
49

Study Title: Honey Bee Larvae Chronic Oral Toxicity

Rationale for Requiring the Data

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

bees, 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 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 honey bee larvae differ in sensitivity from adult bees following chronic exposure.

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

the honey bee as a surrogate test species. The guidances discusses Tier 1 laboratory-based chronic toxicity 

studies of individual honey bee 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 honey bee 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_2013.p

df). Although study design elements for the chronic 21-day toxicity test with honey bee larvae have been 

drafted, EPA requires that the proposed protocol for this study be submitted for review and approval by EPA 

prior to initiating the test. 

Practical Utility of the Data

How will the data be used?

The Tier 1 chronic 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 invertebrates, including insect pollinators, from chronic exposures to pesticides. These 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 effects data for larvae 

are not available, risks to terrestrial insects from chronic 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. 
50

Study Title: Semi-field Testing for Pollinators (tunnel or colony feeding studies)

Rationale for Requiring the Data

Tier 2 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. For eusocial bees, 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 1) studies 

of individual bees do not address possible effects and/or exposure to pesticide residues at the colony-level. 

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

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

relatively controlled exposure conditions of a semi-field study. In addition to providing effects data, these 

studies can provide data on pesticide residues in pollen/nectar of treated plants.

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

the honey bee as a surrogate test species. This guidance describes the tiered testing process and can be found 

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

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

(http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env/jm/mono%282007%2922&

doclanguage=en). Due to the complexities of this study, EPA requires that the proposed protocol for this 

study be submitted for review EPA prior to initiating the test.

Practical Utility of the Data

How will the data be used? 

Tier 2 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 screeninglevel (Tier 1) laboratory-based studies of individual bees are evident in colony-level studies under semi-field 

conditions. The Tier2 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. 
51

Study Title: Semi-field Testing for Pollinators (tunnel or colony feeding studies)

Rationale for Requiring the Data

For eusocial bees, 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 2 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 1 

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 2 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. It is therefore important to determine whether bee 

colonies may be negatively affected where bees are free foraging and have the option to collect/consume 

alternative forage items beyond the spiked food. Since multiple dose levels can be more readily tested, 

feeding studies can help to define dose-response relationships at the whole colony level.

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

the honey bee as a surrogate. This guidance describes the tiered testing process and can be found at: 

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

honey bee colony feeding studies can be found in the EPPO Guidance 170 

(www.nationalbeeunit.com/downloadDocument.cfm?id=191). Although study design elements for the 

feeding study are available through the EPPO Guidance 170, EPA requires that the proposed protocol for 

this study be submitted for review and approval by EPA prior to initiating the test. 

Practical Utility of the Data

How will the data be used?

Tier 2 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 2 tunnel studies. This 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 1 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?

The Tier 2 colony-level data will be used to refine screening-level risk estimates derived using Tier 1 

laboratory-based data on individual bees. The Tier 2 data will help to 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. 
52

Study Title: Field Testing for Pollinators 

Rationale for Requiring the Data

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

chronic risk levels of concern have been exceeded for terrestrial invertebrates and where Tier 2 studies either 

under semi-field tunnel conditions and/or feeding studies have indicated potential adverse effects at the 

colony level. Available toxicity studies from lower-tier studies do not address possible effects and/or 

exposure to pesticide residues at the colony-level under actual pesticide use conditions and where specific 

uncertainties regarding the likelihood of exposure and/or effects remain. Full-field studies also provide an 

opportunity to measure residues in pollen and nectar as well as various matrices (beebread, honey, wax) 

within the colony to obtain a more realistic understanding of exposure.

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

the honey bee as a surrogate. This guidance describes the tiered testing process and can be found at: 

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

honey bee colony studies under full-field conditions can be found in the OCSPP 850.3040 

(http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0018). Useful guidance is 

also available through OCSPP 850.2500 (Field Testing of Terrestrial Wildlife; 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series850.htm) Although design elements 

for the full-field colony-level study are available through the 850.3040 and 850.2500, EPA requires that the 

proposed protocol for this study be submitted for review and approval by EPA prior to initiating the test; the 

protocol should attempt to address specific uncertainties identified in lower-tier studies.

Practical Utility of the Data

How will the data be used? 

Tier 3 colony-level data will be used to further characterize potential risk to non-target organisms including 

listed and non-listed terrestrial social invertebrate species and to refine screening-level risk estimates that 

were based on individual bee responses. The semi-field test is a controlled study that is designed to represent 

potential field-level exposure under relatively controlled conditions and account for hive dynamics, which 

are not achievable from lower-tier 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 the screening-level risk estimates for beneficial terrestrial invertebrates. This study will also be used 

to determine whether more refined (Tier 3) studies are needed to characterize risk. 

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. 
53

Study Title: Residues in Pollen and Nectar

Rationale for Requiring the Data

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

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

to hive 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 bees using

the honey bee as a surrogate. This can be found at: http://www2.epa.gov/pollinator-protection/pollinatorrisk-assessment-guidance. Since residue studies are intended to provide exposure data in multiple matrices 

and under specific application conditions, EPA requires that the protocol is submitted for review and 

approval by EPA prior to initiation of the study.

Practical Utility of the Data

How will the data be used?

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

uncertainties associated with the Tier 1 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 may limit the flexibility of pesticide 

products to comply with FIFRA and the ESA, and could result in use restrictions. 
54

Guideline Number: None (Agency-Wide Guidelines found in USEPA 2000 and 2001)

Study Title: Whole sediment: Chronic invertebrates freshwater & estuarine/marine

Rationale for Requiring the Data

No acceptable chronic sediment toxicity tests for freshwater or marine invertebrates have been 

submitted to satisfy the Agency’s updated data requirements for outdoor uses in 40 CFR Part 158 

(October 26, 2007). Benthic organisms may be exposed to run-off or spray drift from applications used 

in terrestrial environments, based on the fate properties of prothioconazole and its degradates. The 

following lines of evidence suggest the potential for ecologically significant exposure of benthicdwelling organisms to prothioconazole. Prothioconazole has the potential to partition to the sediment 

(log Kow of 4.16), and remain for an extended amount of time (aerobic soil metabolism half-life is up to 

1936 days and aerobic aquatic metabolism of up to 433 days). For freshwater sediment testing, tests on 

an amphipod (e.g., Hyalella azteca) and a midge (e.g., Chironomus dilutus) are requested. Both 

freshwater species, Hyalella and Chironomus differ substantially in their ecological niche (i.e.,

epibenthic vs. infaunal species), life history and phylogeny. For estuarine/marine sediment testing, tests 

on one amphipod species is requested (e.g., Leptocheirus plumulosus). 

In some situations, a tiered testing strategy may be considered for requesting chronic sediment toxicity 

testing. In this approach, sediment toxicity testing would first be conducted with the aforementioned 

species using the subchronic (10-d) sediment toxicity test guidelines (OSCPP 850.1735 and 850.1740). 

Then, pending a comparison of estimated environmental concentrations (EEC) in sediment and pore 

water with toxicity results from the 10-d sediment toxicity studies, the need for one or more chronic 

sediment toxicity studies would be determined. This tiered testing approach has the potential advantage 

of reducing the number of chronic (life cycle) studies that would be needed when results of the 10-d 

(subchronic) tests in conjunction with sediment EECs indicate chronic testing is not likely to alter risk 

assessment conclusions. In some cases, however, this tiered testing approach may result in the conduct 

of both a 10-d (subchronic) and a chronic (life cycle) study.

Practical Utility of the Data

How will the data be used? 

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms 

associated with uses of prothioconazole. The data will reduce uncertainties associated with the current 

risk assessment for benthic species and will improve our understanding of the potential effects of 

prothioconazole on aquatic ecosystems.

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

If the data indicates that registered prothioconazole uses may pose a risk of adverse effects to non-target 

benthic organisms above the Agency Level of Concern, the Agency may explore decision options to 

mitigate this risk. The lack of these data will limit the flexibility the Agency and registrants have in

coming into compliance with the Endangered Species Act, and could result in use restrictions for 

prothioconazole which may otherwise be avoided, or which are unnecessarily severe.

Currently, the 850 guidelines for chronic sediment toxicity testing are being finalized. However, Agencywide guidelines are available for chronic testing of freshwater5 and estuarine/marine organisms6

. 

Therefore, as indicated in 40 CFR Part 158, the registrant is required to submit a protocol for approval 

prior to initiating the study until such time as the OCSPP 850 chronic sediment testing guidelines are 

published.

 5 USEPA 2000. Methods for Measuring the Toxicity and Bioaccumulation of Sediment-associated Contaminants with 

Freshwater Invertebrates. EPA 600/R-99/064. March.

6 USEPA 2001. Methods for Assessing the Chronic Toxicity of Marine and Estuarine Sediment-associated 

Contaminants with the Amphipod Leptocheirus plumulosus. EPA 600/R-01/020. March.
55

12. References 

Food and Agriculture Organization of the United Nations. 2000. FAO PESTICIDE DISPOSAL 

SERIES 8. Assessing Soil Contamination: A Reference Manual. Appendix 2. Parameters 

of pesticides that influence processes in the soil. Editorial Group, FAO Information 

Division: Rome. http://www.fao.org/DOCREP/003/X2570E/X2570E00.htm

Jones, R.D. et al., 2000. Guidance for use of the Index Reservoir and Percent Crop Area Factor in 

Drinking Water Assessments (March 21, 2000). Office of Pesticide Programs, 

Environmental Fate and Effects Division, U.S. Environmental Protection Agency. 

Arlington, VA.

USEPA. 1999. Guidance for Use of the Index Reservoir in Drinking Water Exposure 

Assessments. Arlington, VA.

USEPA. 2000. Drinking Water Screening Level Assessment. Part A: Applying a Percent Crop 

Area Adjustment to Tier II Surface Water Model Estimates for Pesticide Drinking Water 

Exposure Assessments. FQPA Science Policy Document .Public Comment Draft 

September 1, 2000. Federal Register: October 11, 2000 (volume 65, number 197). 

Electronic copy available at http://www.epa.gov/pesticides/trac/science/ .

USEPA. 2002a. Guidance for Selecting Input Parameters in Modeling the Environmental Fate 

and Transport of Pesticides, Version II (February 28, 2002). Office of Pesticide 

Programs, Environmental Fate and Effects Division, U.S. Environmental Protection 

Agency. Arlington, VA.

U.S. EPA. 2002b. Pesticide Root Zone Model (PRZM) Field and Orchard Crop Scenarios: 

Standard Procedures for Conducting Quality Control and Quality Assurance. Office of 

Pesticide Programs, Environmental Fate and Effects Division, U.S. Environmental 

Protection Agency. Arlington, VA. 

U.S. EPA. 2003b. Use of Regional Percent Crop Area Factors in Refined Drinking Water 

Assessments. US EPA Office of Pesticide Programs (OPP), Environmental Fate and 

Effects Division (EFED), Water Quality Technical Team (WQTT). Arlington, VA

USEPA, 2003c. SCI-GROW 2.3: Windows Version of SCI-GROW. September 30, 2003. Office 

of Pesticide Programs, Environmental Fate and Effects Division, U.S. Environmental 

Protection Agency. Arlington, VA. 

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

Programs. United States Environmental Protection Agency (USEPA). Environmental 

Fate and Effects Division. Office of Pesticide Programs. Available at 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf.
56

USEPA. 2006a. 1,2,4-Triazole, Triazole Alanine, Triazole Acetic Acid: Drinking Water 

Assessment in Support of Reregistration and Registration Actions for Triazole-derivative 

Fungicide Compounds. Office of Pesticide Programs Environmental Fate and Effects 

Division. DP Barcode 320682, dated February 28, 2006.

USEPA. 2006b. 1,2,4-Triazole, Triazole Alanine, Triazole Acetic Acid: Human Health Aggregate 

Risk Assessment in Support of Reregistration and Registration Actions for Triazolederivative Fungicide Compounds. Office of Pesticide Programs Health Effects Division 

and Environmental Fate and Effects Division. DP Barcode 322215, dated February 7, 

2006.

U.S. EPA. 2006c. Prothioconazole Tier II Estimated Drinking Water Concentrations (EDWCs) 

for Use in the Human Health Risk Assessment. [Second Revision]. DP Barcode: 320265. 

Office of Pesticide Programs, Environmental Fate and Effects Division. June 2006.

U.S. EPA. 2006d. Environmental Fate and Ecological Risk Assessment for the Registration of 

Prothioconazole (DP Barcode: 324660). Office of Pesticide Programs, Environmental 

Fate and Effects Division. June 2006.

U.S. EPA 2008. Ecological Risk Assessment for the Prothioconazole Section 3 New Use on 

Soybeans and Sugar Beets. DP Barcode: 329925/337791. Office of Pesticide Programs, 

Environmental Fate and Effects Division. January 2008.

U.S. EPA. 2009a. Drinking Water Assessment in Support of the New Use of Prothioconazole on 

Crop Groups 15 and 16 (Cereal Grains and Forage, Fodder and Straw of the Cereal Grains 

Group Except Sweet Corn, Sorghum and Rice) and Sweet Corn (DP Barcode: 369343). 

Office of Pesticide Programs, Environmental Fate and Effects Division. December 2009.

USEPA. 2009b. ECOTOXicology Database, United States Environmental Protection Agency 

(USEPA). Available at http://cfpub.epa.gov/ecotox/ (Accessed March 27, 2015).

U.S. EPA. 2010a. Drinking Water Assessment in Support of the New Use of Prothioconazole on 

Nursery Seed and Seedlings of Conifers and Hardwoods; Foliar Use on Rice and Rice 

Hulls; and Seed Treatment Use on Dried Shelled Pea and Bean Subgroup 6C (Except 

Soybean), Rice and Soybean” (DP Barcodes: D373683, D378621, D378998). Office of 

Pesticide Programs, Environmental Fate and Effects Division. October 2010.

U.S. EPA 2010b. Ecological Risk Assessment in Support of the Prothioconazole Section 3 New 

Uses on Alfalfa Seed, Dry Bean and Pea Seeds (Crop Group 6C), Soybean Seed, Potato 

Seed Pieces, Cereal Grain Seeds, Rice Seed, Nursery Seed, and New Foliar Uses on Rice, 

Nursery Seedlings of Conifers and Hardwoods and an Amendment to the Use on Corn. DP 

Barcodes: 378999, 373681, 378623, 381890. Office of Pesticide Programs, Environmental 

Fate and Effects Division. December 2010. 

U.S. EPA. 2012a. Drinking Water Assessment in Support of the Proposed Prothioconazole 

Section 3 Seed Treatment Uses on Seeds of Cereal Grains Crop Groups 15 & 16 (Except 
57

Sorghum and Rice (DP Barcode 398128). Office of Pesticide Programs, Environmental 

Fate and Effects Division. February 2012.

U.S. EPA 2012b. Environmental Fate and Ecological Risk Assessment for the Proposed New 

Uses of Prothioconazole as a Seed Treatment at an Increased Rate on Cereal Grains of 

Crop Groups 15 & 16, as a Seed Treatment on Corn (Field, Sweet, Pop), and as a Foliar 

Treatment on Soybean at an Increased Rate. DP Barcodes: D395296, 399435. Office of 

Pesticide Programs, Environmental Fate and Effects Division. May 23, 2012. 

U.S. EPA. 2012c. Drinking Water Assessment in Support of the Proposed Prothioconazole 

Section 3 New Uses on Bushberry (Crop Subgroup 13-07B), Low Growing Berry 

Subgroup, Except Strawberry (Crop Subgroup 13-07H) and Cucurbit Vegetables (Crop 

Group 9). (DP Barcode: D405409). Office of Pesticide Programs, Environmental Fate 

and Effects Division. November 2012.

USEPA. 2014a. Toxicity Testing and Ecological Risk Assessment Guidance for Benthic 

Invertebrates. United States Environmental Protection Agency (USEPA). Environmental 

Fate and Effects Division. Office of Pesticide Programs. March 11, 2014. 

USEPA. 2014b. Guidance for Addressing Unextracted Residues in Laboratory Studies. United 

States Environmental Protection Agency (USEPA). Environmental Fate and Effects 

Division. Office of Pesticide Programs. September 12, 2014.

USEPA. 2015a. Screening Level Estimates of Agricultural Uses of Prothioconazole (113961). 

United States Environmental Protection Agency (USEPA). Biological and Economic 

Analysis Division. Office of Pesticide Programs. May 11, 2015.

USEPA. 2015b. BEAD Chemical Profile (BCP) for Registration Review: Prothioconazole 

(113961). United States Environmental Protection Agency (USEPA). Biological and 

Economic Analysis Division. Office of Pesticide Programs. September, 2015.
58

APPENDIX A. Environmental Fate Studies

161-1 Hydrolysis

MRID Citation Reference

46246505 2050563 Riegner, K. (1998) Hydrolysis of [Phenyl-UL-(Carbon-14)]JAU6476 in Sterile 

Aqueous Buffer Solutions. Project Number: M/1110902/4, MR/623/98, 4412. 

Unpublished study prepared by Bayer AG Institute of Metabolism Research and 

Residue Analysis. 41 p.

46246506 2050564 Hellpointner, E. (1993) SXX 0655: Hydrolysis in Buffers. Project Number: 

M/1110379/2, PF/3882. Unpublished study prepared by Bayer AG Institute of 

Metabolism Research and Residue Analysis. 39 p.

161-2 Photodegradation-water

MRID Citation Reference

46246507 2050565 Gilges, M.; Bornatsch, W. (2001) Photolysis of JAU6476 in Sterile Aqueous 

Buffer. Project Number: M/1120917/1, MR/213/01. Unpublished study prepared 

by Bayer Ag Institute of Metabolism Research and Residue Analysis. 71 p.

46246508 DER not 

located

2053922 

Ref

Hellpointner, E. (2001) Determination of the Quantum Yield and Assessment of 

the Environmental Half-life of the Direct Photodegradation in Water of JAU6476. 

Project Number: M/1430957/9, MR/101/01, 214. Unpublished study prepared by 

Bayer Ag Institute of Metabolism Research and Residue Analysis. 39 p.

46246509 DER not 

located 

2053922 

Ref

Hellpointner, E. (1990) Determination of the Quantum Yield and Assessment of 

the Environmental Half-life of the Direct Photodegradation of SXX 0665 in Water. 

Project Number: M/1120358/0, PF3852, ME/24/93. Unpublished study prepared 

by Bayer Ag Institute of Metabolism Research and Residue Analysis. 32 p.

161-3 Photodegradation-soil

MRID Citation Reference

46246510 2050566 Gilges, M. (2001) Photolysis of JAU6476 on Soil Surface. Project Number: 

M/1130918/3, MR/242/00. Unpublished study prepared by Bayer Ag Institute of 

Metabolism Research and Residue Analysis. 47 p.

46359101 DER not 

located

2050571-

ref

Gilges, M. (2001) Photolysis of JAU6476 on Soil Surface. Project Number: 

M/1130918/3, MR/242/00. Unpublished study prepared by Bayer Ag Institut fuer 

Ruckstands-Analytik. 54 p.

162-1 Aerobic soil metabolism

MRID Citation Reference
59

46246511 2050567 Hellpointner, E. (2001) Proazolthion (Proposed) [JAU6476]: Degradation and 

Metabolism of JAU6476 in Aerobic Soils. Project Number: M/1250893/8, 

MR/104/01, 215. Unpublished study prepared by Bayer Ag Institute of 

Metabolism Research and Residue Analysis. 101 p.

46246512 2050568 Gilges, M. (2000) Aerobic Degradation of JAU6476 in Two Soils. Project Number: 

M/1250960/3, MR/549/99. Unpublished study prepared by Bayer Ag Institute of 

Metabolism Research and Residue Analysis. 59 p.

46246513 2050569 Gilges, M. (2001) Degradation of JAU6476-desthio (SXX0665) in Four Soils 

Under Aerobic Conditions. Project Number: M/1251001/0, MR/327/00. 

Unpublished study prepared by Bayer Ag Institute of Metabolism Research and 

Residue Analysis. 58 p.

46246514 2050570 Gilges, M. (2001) Degradation of JAU6476-S-methyl (WAK7861) in Four Soils 

Under Aerobic Condition. Project Number: M/1251002/1, MR/340/00. 

Unpublished study prepared by Bayer Ag Institute of Metabolism Research and 

Residue Analysis. 55 p.

46359102 DER not 

located

Gilges, M. (2000) Aerobic Degradation of JAU6476 in Two Soils. Project Number: 

M/1250960/3, MR/549/99. Unpublished study prepared by Bayer Ag Institut fuer 

Ruckstands-Analytik. 68 p.

46449246 2050568 Gilges, M. (2000) Aerobic Degradation of JAU6476 in Two Soils. Project Number: 

M/1250960/3, MR/549/99. Unpublished study prepared by Bayer Ag Institute of 

Metabolism Research and Residue Analysis. 59 p.

162-3 Anaerobic aquatic metabolism

46246516 2050571 Scholz, K. (2001) Anaerobic Aquatic Metabolism of JAU6476. Project Number:

M/1520919/7, MR/275/01. Unpublished study prepared by Bayer AG Institute of 

Metabolism Research and Residue Analysis. 76 p.

162-4 Aerobic aquatic metabolism 

46246515 2050572 Brumhard, B.; Oi, M. (2001) Aerobic Degradation and Metabolism of the Active 

Ingredient JAU6476 in the Water/Sediment System. Project Number: 

M151/0899/3, MR/395/01, BBJ51. Unpublished study prepared by Bayer Ag 

Institute for Metabolism Research and Residue Analysis. 95 p.

48441901 DER not 

located

Kitschmann, P. (1997) Degradation and Metabolism of [Trifluoromethyl-Phenyl-

(U)-(Carbon 14)] Labeled CGA 279202 in Two Aquatic Systems. Project Number: 

MO/01/001631, 95PK03. Unpublished study prepared by Novartis Crop 

Protection, AG. 149 p.

48441902 DER not 

located

Ulbrich, R. (1997) Degradation and Metabolism of (U)-(Carbon 14)-PhenylGlyoxylat-Labeled CGA 279202 in Two Aquatic Systems. Project Number: 

95UL02, MO/01/001628. Unpublished study prepared by Novartis Crop 

Protection, AG. 132 p.

163-1 Leach/adsorp/desorption

MRID Citation Reference
60

46246449 DER not 

located

2053922 

Ref

Sommer, H. (2001) Estimation of the Absorption Coefficient (Koc) of JAU6476 

on Soil Using High Performance Liquid Chromatography (HPLC). Project 

Number: M/138/1079/9, MR/473/00. Unpublished study prepared by Bayer Ag 

Institut fuer Ruckstands-Analytik. 37 p.

46246450 2050575 Fent, G. (1998) Adsorption/Desorption of (phenyl-UL-(Carbon 14))SXX0665 on 

Four Different Soils. Project Number: BAY28, FM768. Unpublished study 

prepared by Staatliche Lehr- und Forschungsanstalt fuer. 46 p.

46246501 2050576 Hein, W. (1999) Adsorption/Desorption of S-methyl-JAU6476 on Four Different 

Soils. Project Number: BAY30, FM/774. Unpublished study prepared by 

Staatliche Lehr- und Forschungsanstalt fuer Landwirt, Weinbau, Gartenbau. 42 

p.

46246502 DER not 

located 

referenced 

in 2053922

Sommer, H. (2001) Estimation of the Adsorption Coefficient (Koc) of JAU6476-

thiazocine on Soil Using High Performance Liquid Chromatography (HPLC). 

Project Number: M/1381109/3, MR/265/01. Unpublished study prepared by 

Bayer Ag Institute of Metabolism Research and Residue Analysis. 34 p.

46246503 DER not 

located

Riegner, K. (1999) Leaching Behavior of JAU6476 Formulated as 250 EC in Soil 

(Parent Leaching). Project Number: M/1320961/2, MR/098/99, 4430. 

Unpublished study prepared by Bayer AG Institute of Metabolism Research and 

Residue Analysis. 39 p.

46246504 2050573 Babczinski, P. (2001) Aged Soil Column Leaching of JAU6476. Project Number: 

M/1211074/6, MR/364/00. Unpublished study prepared by Bayer AG Institute of 

Metabolism Research and Residue Analysis. 90 p.

46246534 DER not 

located

2053922-

ref

Sabbagh, G.; Arthur, E. (2004) Soil Adsorption Value (Koc) for JAU 6476. 

Project Number: 200817. Unpublished study prepared by Bayer Corp. 19 p.

46246539 2050574 Riegner, K. (1999) Leaching Behaviour of JAU 6476 Formulated as 250 EC in 

Soil (Parent Leaching). Project Number: M/132/0961/2, 109139. Unpublished 

study prepared by Bayer Ag Institute for Metabolism Research and Residue

Analysis. 40 p.

164-1 Terrestrial field dissipation

MRID Citation Reference

46246517 2050577 Wood, S. (2004) Terrestrial Field Dissipation of JAU6476 in California Soil, 

1999. Project Number: J6022102, 200051, F99534/001. Unpublished study 

prepared by Bayer Corp. and A & L Great Lakes Laboratories. 124 p.

46246518 2050578 Wood, S. (2004) Terrestrial Field Dissipation of JAU6476 in Georgia Soil, 

1999. Project Number: J6022101, 110799, F99540/001. Unpublished study 

prepared by Bayer Corp., Bayer Research Farm and A & L Great Lakes 

Laboratories. 135 p.

46246519 2050579 Wood, S. (2004) Terrestrial Field Dissipation of JAU6476 in New York Soil, 

1999. Project Number: J6022103, 200053, F99557/001. Unpublished study 

prepared by Bayer Corp., A.C.D.S. Research, Inc. and A & L Great Lakes 

Laboratories. 134 p.
61

46246520 DER not 

located

2053922 Ref

Lenz, M. (2004) Terrestrial Field Dissipation of JAU6476 in Saskatchewan 

Soil, 1999. Project Number: J6022105, 200134, F99573/001. Unpublished 

study prepared by Bayer Corp., A & L Great Lakes Laboratories and AgQuest. 

137 p.

46246521 DER not 

located

2053922 Ref

Lenz, M. (2004) Terrestrial Field Dissipation of JAU6476 in Manitoba Soil, 

1999. Project Number: J6022106, 200096, F99560/001. Unpublished study 

prepared by Bayer Corp., A & L Great Lakes Laboratories and AgQuest. 137 

p.

46246525 DER not 

located 

2053922 Ref

Schramel, O. (2001) Determination of the Storage Stability of JAU6476 and 

the Metabolites JAU6476-desthio and JAU6476-S-methyl in Soil. Project 

Number: P64190027, MR/644/99. Unpublished study prepared by Bayer Ag 

Institute of Metabolism Research and Residue Analysis. 52 p.

46246526 DER not 

located

2053922

Schramel, O. (2001) Dissipation of JAU 6476 (250 EC) in Soil Under Field 

Conditions (France, Germany, Great Britain, Italy). Project Number: 

RA/2152/98, R812587, R812595. Unpublished study prepared by Bayer Ag 

Institute of Metabolism Research and Residue Analysis. 151 p.

164-2 Aquatic field dissipation

MRID Citation Reference

46246522 2050580 Wyatt, D. (2004) Aquatic Field Dissipation of JAU6476 in a California Rice Field, 

2000. Project Number: J6022401, 200060, F00519/001. Unpublished study 

prepared by Bayer Corp., Agricultural Advisors, Inc. and A & L Great Lakes 

Laboratories. 181 p.

46246523 2050581 Wyatt, D. (2004) Aquatic Field Dissipation of JAU6476 in an Arkansas Rice Field, 

2000. Project Number: J6022402, 200067, F00520/001. Unpublished study 

prepared by Bayer Corp., Shoffner Farm Research and A & L Great Lakes 

Laboratories. 185 p.

46246524 2050582 Wyatt, D. (2004) Aquatic Field Dissipation of JAU6476 in a Cropped Arkansas 

Rice Field, 2000. Project Number: J6022403, 200078, F00520/001. Unpublished 

study prepared by Bayer Corp., Shoffner Farm Research, Battelle and A & L 

Great Lakes Laboratories. 148 p.

165-4 Fish accumulation bioconcentration/biotransformation

46246034 2050583 Dorgerloh, M.; Weber, E. (2001) (Carbon 14)-JAU6476-Bioconcentration and 

Biotransformation in Bluegill (Lepomis macrochirus) Under Flow-Through 

Conditions. Project Number: E/2442023/7, DOM/21003. Unpublished study 

prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 168 p

46246035 2050584 Dorgerloh, M.; Weber, E.; Spiegel, K. (2001) (Carbon 14)-JAU6476-Desthio -

Bioconcentration and Biotransformation in Bluegill (Lepomis macrochirus) Under 

Flow-Through Conditions. Project Number: E/2441731/2, DOM/20006. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 131 p.
62

Appendix B. Ecological Effects Studies 

71-1 Avian Single Dose Oral Toxicity

MRID Citation Reference

46246036 2051002

2050895-

memo

Barkfknecht, R. (1999) JAU6476 techn. ai.: Acute Oral Toxicity for Bobwhite 

Quail (Colinus virginianus). Project Number: 2921561/6, BAR/LD028. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 35 

p.

46246037

Desthio 

metabolite

2051001

2050895-

memo

Grau, R. (1990) SXX 0665 (Technical Grade): Acute Oral LD50 to Bobwhite 

Quail. Project Number: E/2920414/2, VB/009. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 36 p.

48024801 2086131

2086130

Fredricks, T.; Christ, M. (2010) Toxicity of JAU 6476 Technical 

(Prothioconazole) During an Acute Oral LD50 with the Canary (Serinus 

canaria). Project Number: M/364387/01/1, EBJAL065, M/364387/01/1/OCR. 

Unpublished study prepared by Bayer CropScience. 35 p.

71-2 Avian Dietary Toxicity

MRID Citation Reference

46246038 2051000

2050895-

memo

Barfknecht, R. (2001) JAU6476 techn.: 5-Day - Dietary LC50 for Bobwhite Quail 

(Colinus virginianus). Project Number: E/2951563/1, BAR/LC005. Unpublished 

study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 32 p.

46246039

Desthio 

metabolite

2050904

2050895-

memo

Barfknecht, R. (2001) JAU6476-Desthio.: 5-Day - Dietary LC50 for Bobwhite 

Quail (Colinus virginianus). Project Number: E/2951564/2, BAR/LC011. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 34 

p.

46246040 2050919

2050895-

memo

Barfknecht, R. (2001) JAU6476 techn.: 5-Day - Dietary LC50 to Mallard Duck 

(Anas platyrhynchos). Project Number: E/2971562/2, BAR/LC010. Unpublished 

study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 31 p.

71-4 Avian Reproduction

MRID Citation Reference

46246042 2050918

2050895-

memo

Frieling, W. (2000) Reproduction Study in Bobwhite Quail with JAU 6476 (by 

Dietary Admixture). Project Number: 259842, 88353, 259842/MO/00/010540. 

Unpublished study prepared by Notox B.V. 231 p.

46246043

Desthio 

metabolite

2050917

2050895-

memo

Barfknecht, R. (2002) JAU6476-Desthio techn. ai.: Effects of a Subchronic 

Dietary Exposure to the Northern Bobwhite Quail Including Effects on 

Reproduction and Behavior. Project Number: E/2981830/1, BAR/REP006. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 106 

p.
63

46246044 2050916

2050895-

memo

Frieling, W. (2000) Reproduction Study in Mallard Duck with JAU 6476 (by 

Dietary Admixture). Project Number: 259919, 88353. Unpublished study 

prepared by Notox B.V. 207 p.

46246045

Desthio 

metabolite

2050915

2050895-

memo

Frey, L.; Martin, K.; Beavers, J.; et al. (2001) Desthio JAU-6476: A Reproduction 

Study with the Mallard (Anas platyrhynchos). Project Number: 149/181, 110617, 

J6740801. Unpublished study prepared by Wildlife International, Ltd. 200 p.

72-1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

46246018 2051018

2050895-

memo

Dorgerloh, M. (1999) JAU6476 - Acute Toxicity (96 hours) to Rainbow Trout 

(Oncorhynchus mykiss) in a Static Test. Project Number: E/2501657/6, 

DOM/99076. Unpublished study prepared by Bayer Ag Institut fuer RuckstandsAnalytik. 51 p.

46246019 2051019

2050895-

memo

Kern, M.; Lam, C. (2003) Acute Toxicity of JAU 6476 480 SC to the Rainbow 

Trout (Oncorhynchus mykiss) Under Static Conditions. Project Number: 

EBJAX073, J6812201, 200193. Unpublished study prepared by Bayer Corp. 33 

p.

46246020

Desthio 

metabolite

2050914

2050895-

memo

Grau, R. (1990) SXX 0665 techn.: Acute Toxicity to the Rainbow Trout in a 

Static Test. Project Number: E/2800441/9, FF/298. Unpublished study prepared 

by Bayer Ag Institut fuer Ruckstands-Analytik. 28 p. Prothioconazole - Desthio

46246021 2051020

2050895-

memo

Dorgerloh, M.; Sommer, H. (2001) JAU6476-S-Methyl - Acute Toxicity (96 

hours) to Rainbow Trout (Oncorhynchus mykiss) in a Semi-Static Test. Project 

Number: E/2802052/9, DOM/21047, 00699. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 47 p.

46246022 2051021

2050895-

memo

Dorgerloh, M. (1999) JAU6476 - Acute Toxicity (96 Hours) to Bluegill (Lepomis 

macrochirus) in a Static Test. Project Number: E/2521695/0, DOM/99090, 

00586. Unpublished study prepared by Bayer Ag Institut fuer RuckstandsAnalytik. 48 p.

46246023 2051012

2050895-

memo

Kern, M.; Lam, C. (2003) Acute Toxicity of JAU 6476 480 SC to the Bluegill 

(Lepomis macrochirus) Under Static-Renewal Conditions. Project Number: 

200599, EBJAX075, J6810301. Unpublished study prepared by Bayer Corp. 34 

p.

46246024 2051011

2050895-

memo

Grau, R. (1991) SXX 0665: Acute Toxicity to Golden Orfe in a Static Test. 

Project Number: E/2820400/6, FO/1253. Unpublished study prepared by Bayer 

Ag Institut fuer Ruckstands-Analytik. 29 p. Prothioconazole - Desthio

46246025 2051010

2050895-

memo

Dorgerloh, M. (2000) JAU6476 - Acute Toxicity (96 hours) to Common Carp 

(Cyprinus carpio) in a Static Test. Project Number: E/2861781/3, DOM/20010. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 40 

p.

46246026 2051009

2050895-

memo

Kern, M.; Lam, C. (2003) Acute Toxicity of JAU 6476-Desthio to the Fathead 

Minnow (Pimephales promelas) Under Static-Renewal Conditions. Project 

Number: EBJAZ071, J6811202, 200151. Unpublished study prepared by Bayer 

Corp. 35 p. Prothioconazole - Desthio
64

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

46246009 2051013

2050895-

memo

Heimbach, F. (2001) Acute Toxicity of JAU6476 (tech.) to Water Fleas 

(Daphnia magna). Project Number: E/3201675/4, HBF/DM212. Unpublished 

study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 50 p.

46246010 2051014

2050895-

memo

Kern, M.; Lam, C. (2003) Acute Toxicity of JAU 6476 480 SC Formulation to 

the Waterflea (Daphnia magna) Under Static-Renewal Conditions. Project 

Number: EBJAX072, J6820701, 200514. Unpublished study prepared by 

Bayer Corp. 34 p.

46246011 2051015

2050895-

memo

Heimbach, F. (1990) Acute Toxicity of SXX 0665 (techn.) to Waterfleas 

(Daphnia magna). Project Number: HBF/DM/95, E/3200404/1. Unpublished 

study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 28 p. 

Prothioconazole – Desthio

46246012 2051016

2050895-

memo

Dorgerloh. M.; Sommer, H. (2001) Acute Toxicity of JAU6476-S-Methyl to 

Waterfleas (Daphnia magna). Project Number: E/3202119/8, DOM/21055, 

00699/MR/250/01. Unpublished study prepared by Bayer Ag Institut fuer 

Ruckstands-Analytik. 40 p.

46246028 2051007 Hendel, B.; Sommer, H. (2001) Influence of JAU6476 (tech.) on the 

Reproduction Rate of Water Fleas. Project Number: E/3211982/6, 

HDB/RDM67. Unpublished study prepared by Bayer Ag Institut fuer 

Ruckstands-Analytik. 79 p.

47626901 2084467208

4450-memo 

Picard, C. R. (2008) JAU 6476-Desthio - Full Life-Cycle Toxicity Test with 

Sediment-Dwelling Midges (Chirnomus riparius) Under Static Conditions: 

Following OECD Guideline 218: (Prothioconazole Technical, Proline 480 SC 

Fungicide, Provost 433 SC Fungicide). Project Number: 13798/6219, 

EBJAY008, 2000BRP213/183. Unpublished study prepared by Springborn 

Smithers Laboratories. 91

46246013 2051017 Sayers, L. (2004) JAU 6476-Desthio - Acute Toxicity to Crayfish 

(Promcambarus clarkii) Under Static-Renewal Conditions: Amended Final 

Report. Project Number: 13798/6147, EBJAY004, J6880601. Unpublished 

study prepared by Springborn Smithers Laboratories. 49 p.

72-3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation Reference

46246014 2050898

2050895-

memo

Drottar, K.; Kendall, T.; Krueger, H. (2001) JAU 6476: A 96-Hour Shell 

Deposition Test with the Eastern Oyster (Crassostrea virginica). Project Number: 

149A/127, J6831501, 110956. Unpublished study prepared by Wildlife 

International, Ltd. 39 p.

46246016 2050899

2050895-

memo

Drottar, K.; Blankinship, A.; Kendall, T.; et. al. (2002) JAU 6476: A 96-Hour FlowThrough Acute Toxicity Test with the Saltwater Mysid (Mysidopsis bahia). Project 

Number: 149A/128A, J6833101, 110983. Unpublished study prepared by Wildlife 

International, Ltd. 38 p.
65

46246017 2050897

2050895-

memo

Drottar, K.; Palmer, S.; Kendall, T.; et. al. (2002) Desthio JAU 6476: A 96-Hour 

Flow-Through Acute Toxicity Test with the Saltwater Mysid (Mysidopsis bahia). 

Project Number: 149A/129, J6833102, 110979. Unpublished study prepared by 

Wildlife International, Ltd. 39 Desthio metabolite

46246027 2051008

2050895-

memo

Kern, M.; Lam, C. (2004) Acute Toxicity of JAU 6476 Technical to the 

Sheepshead Minnow (Cyprinodon variegatus) Under Static-Renewal Conditions. 

Project Number: EBJA2140, J6830901, 200615. Unpublished study prepared by 

Bayer Corp. 35 p.

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

46246028 2051007

2050895-

memo

Hendel, B.; Sommer, H. (2001) Influence of JAU6476 (tech.) on the 

Reproduction Rate of Water Fleas. Project Number: E/3211982/6, HDB/RDM67. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 79 p.

46246029 2051006

2050895-

memo

Dorgerloh, M.; Sommer, H. (2001) Influence of JAU6476-Desthio on the 

Reproduction Rate of Water Fleas in a Static Renewal Laboratory Test System. 

Project Number: E/3211987/5, DOM/21036. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 73 p. Desthio metabolite

46246030 2050896

2050895-

memo

Blankinship, A.; Kendall, T.; Krueger, H. (2003) Desthio JAU-6476: A FlowThrough Life Cycle Toxicity Test with the Saltwater Mysid (Mysidopsis bahia). 

Project Number: 149A/130A, J6843101, 200485. Unpublished study prepared by 

Wildlife International, Ltd. 107 p Desthio metabolite

46246031 2051005

2050895-

memo

Dorgerloh, M.; Sommer, H. (2001) JAU6476 - Early Life Stage Toxicity to 

Rainbow Trout (Oncorhynchus mykiss) Under Flow-through Conditions. Project 

Number: E/2841699/9, DOM/20028, 00586. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 102 p.

46246032 2051004

2050905

2050895-

memo

Gries, T.; Dorgerloh, M. (2002) JAU6476-Desthio: Early Life-Stage Toxicity Test 

with Rainbow Trout (Oncorhynchus mykiss) Under Flow-Through Conditions. 

Project Number: 1022/013/321. Unpublished study prepared by Springborn 

Laboratories (Europe) Ag. 119 p. Desthio metabolite

72-5 Life cycle fish

MRID Citation Reference

46246033 2051003

2050895-

memo

Drottar, K.; Kendall, T.; Krueger, H. (2004) Desthio JAU 6476: A Flow-Through 

Life-Cycle Toxicity Test with the Fathead Minnow (Pimephales promelas). 

Project Number: 149A/126A, J6851201, 200108. Unpublished study prepared by 

Wildlife International, Ltd. 130 p. Desthio metabolite

72-6 Aquatic org. accumulation

MRID Citation Reference
66

46246034 2050583 

2050414

Dorgerloh, M.; Weber, E. (2001) (Carbon 14)-JAU6476-Bioconcentration and 

Biotransformation in Bluegill (Lepomis macrochirus) Under Flow-Through 

Conditions. Project Number: E/2442023/7, DOM/21003. Unpublished study 

prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 168 p.

46246035 2050584 

2050414

Dorgerloh, M.; Weber, E.; Spiegel, K. (2001) (Carbon 14)-JAU6476-Desthio -

Bioconcentration and Biotransformation in Bluegill (Lepomis macrochirus) Under 

Flow-Through Conditions. Project Number: E/2441731/2, DOM/20006. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 131 

p. Desthio metabolite

122-1 Seed Germination/Seedline Emergence and Vegetable Vigor

MRID Citation Reference

46246049 2050902

2050895-

memo

Sabbert, T. (2004) Tier 1 Seedling Emergence and Vegetative Vigor Non-target 

Phytotoxicity Study Using JAU 6476 480 SC. Project Number: J6451601, 

J6451602, 200951. Unpublished study prepared by Bayer Corp. 84 p.

46246050 2050913

2050895-

memo

Sabbert, T. (2004) Tier 2 Seedling Emergence Non-target Phytotoxicity Study 

Using JAU 6476 480 SC. Project Number: J6451603, 200952. Unpublished 

study prepared by Bayer Corp. 57 p.

123-2 Aquatic plant growth

MRID Citation Reference

46246101 2050912

2050895-

memo

Kern, M.; Banman, C.; Lam, C. (2004) Toxicity of JAU 6476 Technical to 

Duckweed (Lemna gibba G3) Under Static-Renewal Conditions. Project 

Number: EBJAY002, J6883701, 200488. Unpublished study prepared by Bayer 

Corp. 48 p.

46246102 2050911

2050895-

memo

Kern, M.; Banman, C.; Lam, C. (2003) Toxicity of JAU 6476 480 SC to 

Duckweed (Lemna gibba G3) Under Static-Renewal Conditions. Project 

Number: EBJAX189, J6883703, 200672. Unpublished study prepared by Bayer 

Corp. 48 p.

46246103 2050910

2050895-

memo

Kern, M.; Roberts, J.; De Haan, R. (2004) Toxicity of JAU 6476 Technical to the 

Blue-green Alga Anabaena flos-aquae. Project Number: EBJAX078, J6883801, 

200497. Unpublished study prepared by Bayer Corp. 58 p.

46246104 2050909

2050895-

memo

Kern, M.; Banman, C.; Lam, C. (2003) Toxicity of JAU 6476-Desthio to 

Duckweed (Lemna gibba G3) Under Static-Renewal Conditions. Project 

Number: EBJAX084, J6883702, 200469. Unpublished study prepared by Bayer 

Corp. 46 p. Desthio metabolite

46246105 2050908

2050895-

memo

Dorgerloh, M. (2000) JAU6476 Influence on the Growth of the Green Alga, 

Selenastrum capricornutum. Project Number: E/3231610/6, DOM/99107. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 49 

p.

46246106 2050907 Kern, M.; Lam, C. (2004) Toxicity of JAU 6476 480 SC Formulation to the 

Green Alga Pseudokirchneriella subcapitata (a.k.a. Selenastrum 
67

capricornutum). Project Number: EBJAX075, J6883501, 200602. Unpublished 

study prepared by Bayer Corp. 51 p.

46246107 2051024

2050895-

memo

Dorgerloh, M.; Sommer, H. (2001) JAU6476-S-Methyl Influence on the Growth 

of the Green Alga, Selenastrum capricornutum. Project Number: E/3232061/7, 

DOM/21028. Unpublished study prepared by Bayer Ag Institut fuer RuckstandsAnalytik. 48 p.

46246108 2051022 Heimbach, F. (1990) Growth Inhibition of Green Algae (Scenedesmus 

subspicatus) by SXX 0665 Technical. Project Number: E/3230401/3, 

HBF/AL78. Unpublished study prepared by Bayer Ag Institut fuer RuckstandsAnalytik. 30 p.

Prothioconazole - Desthio

46246109 2051023

2050895-

memo

Kern, M.; Lam, C. (2004) Toxicity of JAU 6476 Technical to the Freshwater 

Diatom Navicula pelliculosa. Project Number: EBJAX085, J6883401, 200252. 

Unpublished study prepared by Bayer Corp. 50 p.

46246110 2050903

2050895-

memo

Kern, M.; De Hann, R. (2004) Toxicity of JAU 6476 Technical to the Saltwater 

Diatom Skeletonema costatum. Project Number: EBJAX076, J6883601, 

200434. Unpublished study prepared by Bayer Corp. 49 p.

46246131 205090620

50895 

Heimbach, F. (1990) Growth Inhibition of Green Algae (Scenedesmus 

subspicatus) by SXX 0665 Technical. Project Number: E/3230401/3, 

HBF/AL78. Unpublished study prepared by Bayer Ag Institut fuer RuckstandsAnalytik. 30 p. Desthio metabolite

141-1 850.3020 Honey bee acute contact

MRID Citation Reference

46246046 2050900

2050895-

memo

Schmitzer, S. (2004) Effects of JAU 6476 SC 480 (Acute Contact and Oral) on 

Honey Bees (Apis mellifera L.) in the Laboratory. Project Number: 18351035. 

Unpublished study prepared by Institut fuer Biologische Analytik und Consulting 

IBACON GmbH. 31 p.

46246048 2050901

2050895-

memo

Wilhelmy, H. (1999) JAU 6476 a.i.: Acute Effects on the Honeybee Apis 

mellifera. Project Number: IBA64051, 990222BN. Unpublished study prepared 

by Dr. U. Noack-Laboratorium fuer Angewandte Biologie. 32 p.

850.1790 Chironomid Sediment Toxicity Test

MRID Citation Reference

46246131 2050906 Hendel, B. (2000) Influence of JAU6476 (tech.) on Developmental and 

Emergence of Larvae of Chironomus riparius in a Water-Sediment System. 

Project Number: E/4161775/1, HDB/CH42. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 53 p.

46246132 2050905 Hendel, B. (2000) Influence of SXX 0665 (tech.) on Development and 

Emergence of Larvae of Chironomus riparius in a Water-Sediment System. 
68

Project Number: E/4161808/8, HDB/CH43. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 53 p.

Prothioconazole – Desthio metabolite

Non-Guideline Studies

MRID Citation Reference

46246132 2050905

2050895

Hendel, B. (2000) Influence of SXX 0665 (tech.) on Development and 

Emergence of Larvae of Chironomus riparius in a Water-Sediment System. 

Project Number: E/4161808/8, HDB/CH43. Unpublished study prepared by 

Bayer Ag Institut fuer Ruckstands-Analytik. 53 p. Desthio metabolite

46246013 2051017 Sayers, L. (2004) JAU 6476-Desthio - Acute Toxicity to Crayfish 

(Promcambarus clarkii) Under Static-Renewal Conditions: Amended Final 

Report. Project Number: 13798/6147, EBJAY004, J6880601. Unpublished 

study prepared by Springborn Smithers Laboratories. 49 p. Desthio metabolite

46246015 2050958 Kendall, T.; Nixon, W. (2001) Analytical Method Verification for the 

Determination of JAU-6476 in Saltwater. Project Number: 149C/115, J6112401, 

110957. Unpublished study prepared by Wildlife International, Ltd. 30 p.

46246041 DER not

 

located

Martin, K.; Nixon, W. (2001) Analytical Method Verification for the Determination 

of Desthio JAU 6476 in Avian Diet. Project Number: 149C/113, J6111901, 

99/B/203. Unpublished study prepared by Wildlife International, Ltd. 30 p.

46246118 DER not 

located

Nienstedt, K. (2002) Reproduction Toxicity Test Exposing Folsomia candida 

(Collembola) to JAU6476 Technical. Project Number: 1022/028/641. 

Unpublished study prepared by Springborn Laboratories (Europe) Ag. 34 p

46246119 DER not

located

Moser, T.; Rombke, J. (2001) Acute and Reproduction Toxicity of JAU6476-

Desthio to the Collembolan Species Folsomia candida According to the ISO 

Guideline 11267 "Soil Quality-Inhibition of Reproduction of Collembola 

(Folsomia candida) by Soil Pollutants" (1999). Project Number: P1CR. 

Unpublished study prepared by ECT Oekotoxikologie Gmbh. 28 p. Desthio 

metabolite

46246120 Nienstedt, K. (2001) Reproduction Toxicity Test Exposing Folsomia Candida 

(Collembola) to JAU6476-Desthio. Project Number: 1022/020/641. 

Unpublished study prepared by Springborn Laboratories (Europe) Ag. 36 p.

Desthio metabolite

46246121 Moser, T.; Scheffczyk, A. (2001) Acute and Reproduction Toxicity of JAU6476-

S-Methyl to the Collembolan Species Folsomia candida According to the ISO 

Guideline 11267 "Soil Quality-Inhibition of Reproduction of Collembola 

(Folsomia candida) by Soil Pollutants" (1999). Project Number: P35CR. 

Unpublished study prepared by ECT Oekotoxikologie Gmbh. 24 p.

46246122 Meisner, P. (2000) Acute Toxicity of JAU6476 (tech.) to Earthworms (Eisenia 

fetida). Project Number: E/3101769/7, MPE/RG326/00. Unpublished study 

prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 22 p.

46246123 Meisner, P. (2000) Acute Toxicity of JAU6476 EC 250 to Earthworms (Eisenia 

fetida). Project Number: E/3101795/6, MPE/RG331/00. Unpublished study 

prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 18 p.

46246124 Lechelt-Kunze, C. (2003) Prothioconazole (JAU 6476) SC 480: Acute Toxicity 

to Earthworms (Eisenia fetida) Tested in Artifical Soil with 10% Peat. Project 

Number: E/3102600/2, LKC/RG/A/16/03. Unpublished study prepared by Bayer 

Ag, Institute of Product Info. 23 p.
69

46246125 Meisner, P. (2000) Acute Toxicity of JAU6476-Desthio to Earthworms (Eisenia 

fetida). Project Number: E/3101844/1, MPE/RG338/00. Unpublished study 

prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 20 p. Desthio 

metabolite

46246126 Heimbach, F. (2000) Acute Toxicity of JAU6476-S-Methyl to Earthworms 

(Eisenia fetida). Project Number: E/3101743/9, HBF/RG321. Unpublished 

study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 19 p.

46246127 Meisner, P. (2000) Influence of JAU6476-EC 250 on the Reproduction of 

Earthworms (Eisenia fetida). Project Number: E/3121753/2, MPE/RG325. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 27 

p.

46246128 Meisner, P. (2000) Influence of JAU6476-Desthio on the Reproduction of 

Earthworms (Eisenia fetida). Project Number: E/3121799/2, MPE/RG322/00. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 24 

p. Desthio metabolite

46246129 Heimbach, F. (2000) Influence of JAU6476-S-Methyl on the Reproduction of 

Earthworms (Eisenia fetida). Project Number: E/3121713/8, HBF/RG317. 

Unpublished study prepared by Bayer Ag Institut fuer Ruckstands-Analytik. 24 

p.

46246329 Becker, H.; Biedermann, K. (1991) Dose Range-Finding Embryotoxicity Study 

(Including Teratogenicity) with SXX 0665 Technical in the Rabbit (Dermal 

Application). Project Number: 309554, R5425, T1040386. Unpublished study 

prepared by RCC Umweltchemie Ag. 92 p.

46246330 Becker, H.; Biedermann, K. (1997) Dose Toleration Study to a Developmental 

Toxicity Study with JAU 6476 in the Rabbit. Project Number: 650970, R7003, 

T/5055258. Unpublished study prepared by RCC Umweltchemie Ag. 112 p.

46246415 Schmidt, U. (1999) JAU 6476 Investigation of the Inhibition of Cytochrome 

P450 Dependent Monooxygenases in Liver Microsomes (in vitro). Project 

Number: 28400, 109060. Unpublished study prepared by Bayer Ag Inst. of 

Toxicology. 20 p.

46246440 Moore, K.; Budzowski, K. (1998) A Liquid Chromatographic Method for the 

Determination of JAU 6476 in Dose Preparations. Project Number: 98/899/RI, 

108384. Unpublished study prepared by Bayer Corp. 16 p.

46246441 Rinke, M. (2001) Assessment of Ovarian Findings in Rodents After Treatment 

with SXX0665. Project Number: MO/02/000457. Unpublished study prepared 

by Bayer Ag Inst. of Toxicology. 15 p.

46246442 Stropp, G. (1996) Validation of the Magnusson-Kligman Maximization Test 

Method Used by the Fachbereich Toxlkologie, Bayer AG Performed in Guinea 

Pigs of the Strain Hsd Poc: DH. Project Number: T/1060339, 24605. 

Unpublished study prepared by Bayer Ag Inst. of Toxicology. 31 p.

46246443 Vohr, H. (2002) Validation of the Magnusson-Kilgman Maximization Test 

Method Used by the Fachbereich Toxikologie, Bayer AG Performed in Guinea 

Pigs of the Strain Crl:HA with Alpha-Hexylzimtaldehyd. Project Number: 

T/8071893, AT00083. Unpublished study prepared by Bayer Ag Inst. of 

Toxicology. 30 p.

46246444 Moore, K. (1991) A Liquid Chromatographic Method for the Determination of 

SXX 0665 in Rodent Ration. Project Number: 101258. Unpublished study 

prepared by Mobay Chemical Corp. 18 p.
70

46246445 Tolliver, M. (2004) Tier II Summaries for Toxicology Studies. Project Number: 

201003. Unpublished study prepared by Bayer CropScience LP. 474 p.

46467302 Wahle, B. (2004) A Subchronic Toxicity Testing Study in the CD-1 Mouse with 

1,2,4-Triazole. Project Number: 03/S71/QC, 201052, TZ524902. Unpublished 

study prepared by Bayer Corp. and Bayer Ag Inst. of Toxicology and Dow 

Chemical Company. 765 p.

46501401 Robaugh, D. (2005) Dietary Exposure Monitoring: Determination of 1,2,4-

Triazole, Triazole Alanine and Triazole Acetic Acid Residues in Eggs. Project 

Number: U/S/TRIAZOLE/TASK/FORCE/1490, METH/160, 

U/S/TRIAZOLE/TASK/FORCE/1478. Unpublished study prepared by Pyxant 

Labs Inc. and Morse Laboratories, Inc. 351 p.

46616402 Jensen, T. (2004) The Homogeneity and Stability of 1, 2, 4-Triazole Technical 

in Rodent Ration Using Purina Mills Certified Rodent Diet 5002 Meal. Project 

Number: 03/H72/RR, 201185. Unpublished study prepared by Bayer Corp. 15 

p.

47626901 Picard, C. R. (2008) JAU 6476-Desthio - Full Life-Cycle Toxicity Test with 

Sediment-Dwelling Midges (Chirnomus riparius) Under Static Conditions: 

Following OECD Guideline 218: (Prothioconazole Technical, Proline 480 SC 

Fungicide, Provost 433 SC Fungicide). Project Number: 13798/6219, 

EBJAY008, 2000BRP213/183. Unpublished study prepared by Springborn 

Smithers Laboratories. 91 p.

48024309 Rupprecht, K.; Young, B. (2010) Tier 2 Summary of the Toxicological Studies 

and Exposure Data and Information on the Plant Protection Product for 

Penprome 177FS. Project Number: M/365048/01/1/OCR, M/365048/01/1, 

US0005. Unpublished study prepared by Bayer CropScience LP. 25 p.

48024311 Bulman, P.; Henry, S. (2010) Penprome 177FS Seed Treatment Fungicide. 

Project Number: M/365443/01/1/OCR, M/365443/01/1, BYFCAN007. 

Unpublished study prepared by Bayer CropScience. 1584 p.

48526701 Hall, T.; Tang, J.; Kwiatkowski, P. (2011) Bayer CropScience Response to US 

EPA Environmental Fate and Ecological Risk Assessment in Support of 

Prothioconazole Section 3 New Seed Treatment and Foliar Uses (December 

13, 2010). Project Number: US0196. Unpublished study prepared by Bayer 

Cropscience LP. 24 p.
71

Appendix C. Prothioconazole Incidents

A search for ecological incidents related to prothioconazole use, conducted on August 27, 2015,

yielded 15 incidents. All of the incidents were classified as “possible” certainty (excludes incidents 

classified as ‘unlikely’ the result of or ‘unrelated’ to prothioconazole), which is summarized below.

Table C. Prothioconazole Incidents, as Reported in the EIIS Database

Incident ID 

#

State, 

County

Magnit

ude Year Description Legality

I021485-

021

MN, 

Otter Tail

500 

Acres 2009 An application of the product Proline (a.i. prothioconazole) onto 500 acres of soybean in Otter Tail County, MN allegedly caused delayed maturity to 100% of the crop. Misuse

I022286-

036 GA, Irwin 40 Acres 2010

On Aug 11, 2010 in Irwin County, GA, 100% of 40 acres of treated peanut crop suffered from 

leaf burn after being treated with the products Provost (a.i. prothioconazole, tebuconazole) 

and Asana XI (a.i. esfenvalerate). Alleged phytotoxic reaction to products following application 

to peanut crop.

Undetermined

I022392-

027

GA, 

Colquitt

50% of 

460 

Acres

2010

On August 23, 2010 in Colquitt County, GA 50% of 460 acres of peanut experienced leaf burn 

after the products Provost (a.i. prothioconazole, tebuconazole) and Sniper (a.i. bifenthrin) 

were applied. Alleged phytotoxic reaction to product following application to peanuts crop.

Undetermined

I023082-

034

IA, 

Clinton

100% 

of 70 

Acres

2011

On June 15, 2011 in Clinton County, IA 100% of 70 acres of corn was damage after the 

products Laudis (a.i. tembotrione), Stratego Yld (a.i. trifloxystrobin, prothioconazole), and 

Atrazine (non-specific) was applied to the corn field. Alleged phytotoxic reaction to product 

following application to corn crop. The adverse effects included leaf wrapping, whitening at 3 

leaf or later. The Compliance Manager for the Registrant noted an application error and off 

label use.

Misuse 

(intentional)

I023082-

051

IL, 

Tazewell 47.6% 2011

On June 9, 2011 in Tazewell County, IL 47.6% of 40 acres of corn exhibited leaf burn after an 

application of the products Stratego Yld (a.i. Trifloxystrobin and prothioconazole), Capreno (a.i. 

thiencarbazone and tembotrione) and atrazine (non-specific). Alleged phytotoxic reaction to 

product following application to corn crop. The Compliance Manager for the Registrant 

suggested the probable cause was high temperatures.

Undetermined

I023302-

029

GA, 

Calhoun

100% 

of 210 

Acres

2011

In Calhoun County, GA, on August 29, 2011 100% of 210 acres of peanuts experienced leaf 

burn and leaf loss after an application of the product Provost (a.i. prothioconazole and a.i. 

tebuconazole) was used. The grower noticed leaf burn several days after the application. 

Grower alleges that aerial applicator applied only a mixture of provost and water. Application 

was made during a day when temperatures reached nearly 100 degrees. Due to heat and 

humidity and possible water evaporation of the spray carrier could have led to a more 

concentrated amount of provost being sprayed on the peanuts. Grower alleges phytotoxic 

reaction to product following application to peanuts crop. Application method: Aerial.

Registered Use

I023302-

030

GA, 

Wilcox

100% 

of 100 

Acres

2011

In Wilcox County, GA, on August 17, 2011 100% of 100 acres of a peanut crop experienced leaf 

burn and leaf drop after a commercial application of the product Provost (prothioconazole 

and tebuconazole) . Alleged phytotoxic reaction to product following application to the 

peanut crop. Field agent for the Registrant suggested high temperatures and the grower 

mixing dimilin and boron with Provost as the probable cause.

Registered Use

I023302-

031 GA, Dooly

100% 

of 155 

Acres

2011

On August 19, 2011 in Dooly County GA 155 acres of peanuts was suffered leaf burn and leaf 

loss after the application of the products Provost (a.i. prothioconazole and a.i. 

tebuconazole)and Bifenthrin (a.i bifenthrin). Alleged phytotoxic reaction to product following 

application to peanut crop. The Registrant concluded the probable cause was high 

temperature.

Registered Use

I023302-

038

GA, 

Colquitt

525 

Acres 2011

In Colquitt County, Ga. on Aug 23, 2011 100% of 525 treated acres of peanuts displayed 

symptoms of leaf burn and leaf drop. The commercially applied products Provost (a.i. 

prothioconazole) and FenvaloStar (a.i. esfenvalerate) are alleged to cause phytotoxic reaction.

Registered Use

I023390-

022

GA, 

Wilcox

100% 

of 100 

Acres

2011

On August 8, 2011 in Wilcox County, GA 100% of 100 acres of peanuts exhibited leaf burn and 

leaf drop after the product Provost (a.i. prothioconazole, tebuconazole) was applied. Alleged 

phytotoxic reaction to product following application to peanut crop. The Registrant suggested 

high temperatures may have been the cause of the leaf burn.

Registered Use

I023554-

008

FL, Santa 

Rosa

56% of 

450 

Acres

2011

September 1, 2011 in Santa Rosa County, FL it was first observed 253 acres of peanuts were 

exhibiting severe leaf burn and leaf drop. Earlier in the growing season the peanuts were 

sprayed with Provost (a.i. prothioconazole and tebuconazole). The incident is under 

investigation.

Undetermined

I024295-

045

IL, 

Lawrence

100% 

of 64 

Acres

2012

On June 6, 2012 in Lawrence County, IL 100% of 64 acres of small grains may have experienced 

desiccation and phytotoxic reaction to the products Prosaro (a.i. prothioconazole) and 

Baythroid Xl (a.i. beta-cyfluthrin). Alleged phytotoxic reaction to product following application 

to the small grain crop. Investigation predetermined from the spray pattern there was a minor 

tank contamination in one of the loads.

Registered Use
72

Incident ID 

#

State, 

County

Magnit

ude Year Description Legality

I024295-

047

GA, 

Thomas

100% 

of 7 

Acres

2012

On June 22, 2012 in Thomas County, GA 100% of 7 acres of peanuts experienced leaf burn 

after the product Proline (a.i. prothioconazole) was applied. Alleged phytotoxic reaction to 

product following application to peanuts crop. The representative for the Registrant 

suggested the probable cause may have been tank mix partner.

Registered Use

I024431-

042

ND, 

Griggs

100% 

of 400 

Acres

2012

On July 2, 2012 in Griggs County, ND 100% of 400 acres of spring wheat desiccated after the 

application of the product Prosaro 421 SC Fungicide (a.i. prothioconazole, tebuconazole). 

Alleged phytotoxic reaction to product following application to spring wheat crop. Adverse 

effects; showed desiccation. The Registrant suggested the probable cause was tank 

contamination. Waiting for lab results.

Misuse

I025344-

022

ND, 

County 

not listed

100% 

of 120 

Acres

2013 Allegedly an application of the product Ernesto Silver (a.i. prothioconazole) resulted in a 

phytotoxic reaction to 100% of 120 acres of a potato crop. Undetermined

Uncertainties Related to the Use of Incident Information from the Ecological Incident 

Information System 

Incident data are used in risk assessments to provide evidence that the risk predictions from the 

screening level assessment are supported by actual effects in the field. Incident reports submitted to 

EPA since approximately 1994 have been tracked by assignment of incident numbers in an Incident 

Data System (IDS), microfiched, and then entered to a second database, the Ecological Incident 

Information System (EIIS). Additionally, there is an on-going effort to enter information to EIIS on 

incident reports received prior to establishment of current databases. Incident reports are not 

received in a consistent format (e.g., states and various labs usually have their own formats), may 

involve multiple incidents involving multiple chemicals in one report, and may report on only part 

of a given incident investigation (e.g., residues). 

Incidents entered into EIIS are categorized into one of several certainty levels regarding the 

likelihood that a particular pesticide is associated with the incident: highly probable, probable, 

possible, unlikely, or unrelated. In brief, “highly probable” incidents usually require carcass 

residues and/or clear circumstances regarding the exposure. “Probable” incidents include those 

where residues were not available and/or circumstances were less clear than for “highly probable.” 

“Possible” incidents include those where multiple chemicals may have been involved and it is not 

clear what the contribution was of a given chemical. The “unlikely” category is used, for example, 

where a given chemical is practically nontoxic to the category of organism killed and/or the 

chemical was tested for but not detected in samples. “Unrelated” incidents are those that have been 

confirmed to be not pesticide-related.

Incidents entered into the EIIS are also categorized as to use/misuse. Unless specifically confirmed 

by a state or federal agency to be misuse, or there was very clear misuse such as intentional baiting 

to kill wildlife, incidents are not typically considered misuse. 

The number of documented kills in EIIS is believed to be a small fraction of total mortality caused 

by pesticides. Mortality incidents must be seen, reported, investigated, and have investigation 

reports submitted to EPA to have the potential for entry into the database. Incidents often are not 

seen, due to scavenger removal of carcasses, decay in the field, or simply because carcasses may be 

hard to see on many sites and/or few people are systematically looking. Poisoned animals may also 

move off-site to less conspicuous areas before dying. Incidents may not get reported to appropriate 

authorities capable of investigating the incident for a variety of reasons including the finder may not 

know of the importance of reporting incidents, may not know who to call, may not feel they have 

the time or desire to call, or may hesitate to call because of their own involvement in the kill. 

Incidents reported may not get investigated if resources are limited or may not get investigated 
73

thoroughly, with residue analyses, for example. Also, if kills are not reported and investigated 

promptly, there will be little chance of documenting the cause, since tissues and residues may 

deteriorate quickly. Reports of investigated incidents often do not get submitted to EPA, since 

reporting by states is voluntary. 

Furthermore, the database relies heavily on registrant-submitted incident reports, and registrants are 

currently only required to submit detailed information on ‘major’ ecological incidents, while 

‘minor’ incidents are reported aggregately. 

Based on the 40 CFR (§159.184 Toxic or adverse effect incident reports), an ecological incident is 

considered ‘major’ if any of the following criteria are met:

Fish or wildlife:

(A) Involves any incident caused by a pesticide currently in Formal Review for ecological 

concerns. 

(B) Fish: Affected 1,000 or more individuals of a schooling species or 50 or more 

individuals of a non-schooling species. 

(C) Birds: Affected 200 or more individuals of a flocking species, or 50 or more individuals 

of a songbird species, or 5 or more individuals of a predatory species. 

(D) Mammals, reptiles, amphibians: Affected 50 or more individuals of a relatively common 

or herding species or 5 or more individuals of a rare or solitary species. 

(E) Involves effects to, or illegal pesticide treatment (misuse) of a substantial tract of habitat 

(greater than or equal to 10 acres, terrestrial or aquatic). 

Plants: 

(A) The effect is alleged to have occurred on more than 45 percent of the acreage exposed to 

the pesticide.

All other ecological incidents are considered ‘minor’ and only need to be aggregately reported. 

‘Minor’ incidents reported by the registrants are not included in the EIIS database. Therefore, for 

example, an incident could affect 900 fish, 150 birds, 45 mammals, and 40% of an exposed crop 

and not be included in the EIIS database [unless is it reported by a non-registrant (e.g., an incident 

submitted by a state agency – which are not systematically collected)]. Therefore, because the 

number of documented kills in EIIS is believed to be a small fraction of total mortality caused by 

pesticides, absence of reports does not necessarily provide evidence of an absence of incidents. 
74

Appendix D. Example SIP Result for Prothioconazole Parent Compound

Inputs

Parameter Value

Chemical name Prothio-Parent

Solubility (in water at 25oC; mg/L) 344

Mammalian LD50 (mg/kg-bw) 6200

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 100

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 2000

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 982

Bobwhite quail NOAEC (mg/kg-diet) 0

NOAEC (mg/kg-diet) for other bird species

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird species

Body weight (g) of 2nd other avian species

Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 59.1680 59.1680

Adjusted toxicity value (mg/kg-bw) 4768.7955 76.9161

Ratio of exposure to toxicity 0.0124 0.7693

Conclusion*

Drinking water exposure alone is 

NOT a potential concern for 

mammals

Drinking water exposure alone is 

NOT a potential concern for 

mammals

Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 278.6400 278.6400

Adjusted toxicity value (mg/kg-bw) 1440.8590 48.7195

Ratio of exposure to acute toxicity 0.1934 5.7193

Conclusion*

Exposure through drinking water 

alone is a potential concern for 

birds

Exposure through drinking water 

alone is a potential concern for 

birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with 

other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has 

potential for effects to non-target animals.
75

Appendix E. STIR Results

Input

Application and Chemical Information

Enter Chemical Name Prothioconazole

Enter Chemical Use

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) 344.264

Enter Chemical Vapor Pressure (mmHg) 3.00E-09

Enter Application Rate (lb a.i./acre) 0.178

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 2000

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 6200

Enter Lowest Rat Inhalation LC50 (mg/L) 4.99

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) 5.56E-05

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 6.99E-06

Adjusted Inhalation LD50 8.98E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 7.78E-07

Exposure not Likely 

Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.71E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 1.91E-03

Exposure not Likely 

Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 5.56E-05

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 8.78E-06

Adjusted Inhalation LD50 2.97E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 2.96E-08

Exposure not Likely 

Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 2.15E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 7.24E-05

Exposure not Likely 

Significant