1

March 13, 2013

Meeting between Syngenta Crop Protection LLC, NMFS, EPA and USDA

8th Biological Opinion of the case of

Northwest Coalition for Alternative Pesticides v. National Marine Fisheries Service

Update on Prometryn Information and Data 

for the Assessment of Potential Effects 

on Threatened and Endangered 

Salmon in the Pacific Northwest
2

Goals of Meeting

● Update use information and scientific data since last meeting of 

September 28, 2011

- Briefly review the best available information and data submitted by 

Syngenta

- Describe changes in the amended volume

- Provide clarifications or answer any question NMFS, EPA or USDA 

may have on these data

● Objective: Review best available data pertaining to the risk 

assessment of prometryn to listed salmonid species, their food 

resources or habitat 

Syngenta is providing updates (shown in GREEN) to the data and 

presentation provided on September 28, 2011. Updates will be presented 

in the main slides, and supporting slides from the September 28, 2011 

meeting are provided as Appendices.
3

Agenda

● Product Use and Characterization (Cherilyn Strader)

- General information and registered products

- Label use restrictions

● Geographical Scope of Prometryn Use (JiSu Bang)

● Best Available Environmental Fate Data and Exposure 

Characterization (Theodore Valenti & Natalia Peranginangin)

● Best Available Ecotoxicology Data (Theodore Valenti)

● Conclusions (Cherilyn Strader)
4

Product Use and Characterization

Detailed information available under Section 4.4 of the report “Prometryn: Review 

and Assessment of the Potential Impact of Prometryn on Endangered and 

Threatened Pacific Salmonid Species, Assessment Amendment 2” (Pages 28 to 32; 

Submitted March 8, 2013)
5

General Information On Prometryn

● Used to control many annual broadleaf weeds and grasses

● Applied both pre- and post-emergence

● Acts by inhibiting photosynthesis at photosystem II

● Approved for use in cotton, celery, carrot, cilantro, okra, parsley, 

rhubarb, celeriac, Chinese celery, Florence fennel, dill (CA & FL only), 

pigeon peas (PR only)

● Permitted for use on 24c labels: transplanted celery (CA); seed carrot, 

seed parsley, seed parsnip, and seed dill (WA); carrots, parsley, and 

coriander grown for seed (OR) 

● Scheduled to begin Registration Review in March 2013

 
6

Registered Products

Technicals EPA Reg. No. Registrant Active Ingredient(s)

Prometryn Technical 100-542 Syngenta Crop Protection, LLC Prometryn

Prometrex® Technical 46386-2

Verolit Chemical 

Manufacturing CO, LTD

Prometryn

End Use Products

Caparol® 4L 100-620 Syngenta Crop Protection, LLC Prometryn

Vegetable Pro®/Cotton Pro® 66222-15

Makhteshim Agan of North 

America, Inc

Prometryn

Prometryne 4L 9779-297 Winfield Solutions, LLC Prometryn

Prometryne 4L 34704-692 Loveland Products, Inc Prometryn

Formulated Mixture

Suprend® (cotton only) 100-1163 Syngenta Crop Protection, LLC

Prometryn + 

Trifloxysulfuron
Prometryn Maximum Rates and Application Methods

Usea Max. Single Appl. Rate (lb ai/A) Max. Number Appl. per Year

Celery 2 1

Cotton 2.4 Variesb

Dill 1.6 1

Fennel 2 1

Parsley 2 1

Carrot 2 Variesc

Celeriac 2 1

Cilantro 1.6 1

Chinese celery 2 1

Okra 1.5 1

Pigeon Peas 3 1

Rhubarb 2 1

a

IR-4 application to add snap beans is currently in review at EPA (PRIA date end of Sept., 2013)

b Application times: Pre-plant (max application of 2.4 lb ai/A); post-emergence (up to 3 applications totaling 2 lb 

ai/A); lay-by (maximum 1.6 lb AI/A); and winter weed control (maximum 2.4 lb ai/A); not to exceed annual total max 

of 5.5 lb ai/A 

c Application times: preemergence (max application of 2 lb ai/A); and postemergence (up to 2 applications of 2 lb 

ai/A); not to exceed annual total max of 4 lb ai/A 
8

Examples of Labeled Use Restrictions Relevant to 

Endangered Species Assessments

● Maximum individual rates, number of allowable applications, timing

● Geographical and Soil Specific Rate Restrictions

- Use rates often state-specific

- Soil-type restrictions are state and crop specific

- Generally lower rates (or no use in certain states) on sand and sandy loam 

soils, or lower organic matter; higher rates on all loamy, silt, fine texture 

soils, or higher organic matter

● Spray Drift Restrictions

- Spray droplet size/nozzles, wind speed, ground, aerial, and chemigation

specific restrictions

● Surface Runoff Restrictions:

- Do not apply to water, where surface water is present, below high-tide mark, 

or where runoff is likely to occur
9

Example of Soil/Geography Specific Restrictions for 

Transplanted Celery, Chinese Celery & Florence Fennel

2.0 pt/acre Caparol 4L = 1.0 lb/acre prometryn
10

Spray Drift Restrictions

● Apply only as a medium or coarser spray (ASABE standard 572.1) or a 

volume mean diameter of ≥300 microns for spinning atomizer nozzles

● Apply only when the wind speed is 2-10 mph

● Use high flow rate nozzles to apply the highest practical spray volume

● Use the minimum number of nozzles that provide uniform coverage

● Spray drift restrictions for ground boom application:

- Do not apply with a nozzle height greater than 4 feet above the crop 

canopy pre-plant, pre-emergence and post-emergence

- Pre-plant incorporated or pre-emergence: use flat fan nozzle tips

- Post-emergence band: use drop extraction tubes off-center nozzle tips

- Post-emergence broadcast: use flat fan or off-center nozzle tips

● Spray drift restrictions for aerial application:

- Aerial applications only permitted on cotton

- None of the crops grown within the 28 salmon ESU/DPS’s allow 

aerial applications 
Prometryn in Glyphosate and/or ALS Resistant Weed 

Management

Untreated Check Treated with herbicide program that 

included prometryn (Caparol® 4L) 

● Diversity of weed control methods needed.

- Prometryn is an essential tool for many minor use crop growers. 

● Prometryn enables application of herbicide with an additional mode 

of action (PSII-inhibitor).

● Resistant palmer amaranth and horseweed have become 

significant problems in southern states, particularly in cotton. 
12

Prometryn Salmon BiOp Submissions of 

Best Available Information and Data to EPA & NMFS, 

Docket EPA-HQ-OPP-2008-0654

● June 30, 2011 

- Specific Use Restrictions & Product Labels to be Considered When Assessing the Potential Impact of 

Prometryn on Threatened & Endangered Pacific Salmonid Species (MRID 48541602) 

- Review & Assessment of the Potential Impact of Prometryn on Endangered & Threatened Pacific 

Salmonid Species (MRID 48541604) 

● July 18, 2011 

- Specific Use Restrictions document (48541602) + Review & Assessment document (48541604)

- Aerobic Aquatic Degradation & Metabolism study (MRID 48541603)

- Acute Toxicity of Prometryn to Bluegill Sunfish (MRID 48541601) & Common Carp (MRID 48541606) 

- Acute Toxicity of Formulation A1114U to Rainbow Trout (MRID 48541607), Common Carp (MRID 

48541608) & Green Algae (MRID 48541611)

- Acute Toxicity of Formulation A3953F to Rainbow Trout (MRID 48541610), Daphnia magna (MRID 

48541605) & Green Algae (MRID 48541609)

● December 20, 2011 

- Amended assessment including: inert comparison, flowing water body modeling & corrected anaerobic 

aquatic degradation half-life value (MRID 48697901)

- Rebuttal of CA Red-legged frog end-points (MRID 48697902)

● March 8, 2013 

- Amended assessment including: updated water monitoring data, corrections to the environmental fate 

conceptual model & updated ecotoxicity endpoints

- Rainbow trout acute toxicity study
13

Other Best Available Data Recently Submitted as 

Conditions of Registration1

Guideline Study MRID Subm. Date

860.1300 Nature of Residue – Plants 48727502 1/24/2012

860.1500 Crop Field Trials – Carrot 48727501 1/24/2012

870.7800 Immunotoxicity 48936501 9/11/2012

870.6200 Acute & Subchronic Neurotoxicity 49021201-04 12/17/2012

850.1350 Aquatic Invertebrate Life-cycle 

(saltwater)

3/5/2013

1 Letter from J. Tompkins to J. Abbott, Subject: “Label Amendment (New Use on Carrot, Celeriac, Cilantro, Okra, Parsley, and 

Leaf Petioles (Crop Subgroup 4B) Prometryn Technical EPA Reg. No. 100-542 Caparol4L EPA Reg. No. 100-620 Application 

Dated August 13, 2008”, January 5, 2011. 
14

Geographic Scope of Prometryn Uses

The analysis has been updated using recent data that has become available since 

the original report was generated. Detailed information available under Section 4 of 

the report “Prometryn: Review and Assessment of the Potential Impact of 

Prometryn on Endangered and Threatened Pacific Salmonid Species, Assessment 

Amendment 2” (Pages 9 to 27; Submitted March 8, 2013)
15

The analyses with new information show that use patterns have not 

appreciably changed since prior assessment. 

• Prometryn use slightly increased in 2010 but total use pattern is similar 

since 2008 

• Still no cotton use found within the 28 ESU/DPSs 

 

0

50

100

150

200

250

300

350

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Total Use

(Thousand lb per year)

Year 

Total Annual Use

Highlight of Updates 
All Crop Uses 

Prometryn Use Locations 

Relative to the Listed Salmon 

ESU/DPS in CA

80%

20%

Total Prometryn Applications outside ESU/DPS

Total Prometryn Applications within ESU/DPS

Average Annual Use (lbs/yr) 

Reported in CA PUR Database 

(2000 – 2010) 

by Pesticide Use Reporting District
Cotton Only 

Cotton Only 

Prometryn Use Locations 

Relative to the Listed Salmon 

ESU/DPS in CA

100%

Total Prometryn Applications outside ESU/DPS

Total Prometryn Applications within ESU/DPS

Average Annual Use (lbs/yr) Reported 

in CA PUR Database (2000 – 2010) 

by Pesticide Use Reporting District 

No Prometryn uses on Cotton between 

2000 and 2010 in the CA ESU/DPS
18

Summary of Comprehensive Spatial Analysis

● Additional data presented that was not included in amended report 

in order to provide the most up-to-date information

● The additional data presented in the current amended report do not 

change the conclusions

● There is minimal potential for prometryn use within the ESU/DPSs 

in Oregon, Washington, and Idaho 

● No prometryn use on cotton within any of the 28 ESU/DPSs

- No aerial use of prometryn within any of the 28 ESU/DPSs

● There is minimal use of prometryn on other specialty crops within 

the 28 ESU/DPSs 

● Overall, the results indicate that current and potential use of 

prometryn within or adjacent to the 28 ESU/DPS in the Pacific 

Northwest and California is minimal
19

Environmental Fate and Exposure

Monitoring data presented in the slides have been updated using additional data sources and up 

to 2012 data. Detailed information available under Sections 5-8 of the report “Prometryn: Review 

and Assessment of the Potential Impact of Prometryn on Endangered and Threatened Pacific 

Salmonid Species, Assessment Amendment 2” (Pages 32 to 51; Submitted March 8, 2013)
20

Environmental Fate

Parameters Available Data and Source

Aerobic soil t1/2 

(days)

270 

MRID 00148338

Terrestrial field 

dissipation t1/2 

(days)

70, 86, 71, 103

MRIDs 41546401-4, 42253901-4

Aerobic aquatic

t1/2 (days)

110.4, 235.8, 38

MRID 48541603 and EUFOOTPRINT

Koc (mL/g) 57 – 3014 (>47 values)

MRID 41875901, Rao and 

Davidson (1982), Seol and Lee 

(2000), Baskaran and Kennedy 

(1999), Turin and Bowman 

(1997)

Mobility via

column leaching

Low (est. Koc=1228 mL/g)

MRID 41875904

● Major dissipation pathways driven 

by aerobic soil degradation, 

aerobic aquatic degradation, 

sorption.

● No degradation via abiotic pathways 

(e.g. aqueous and soil photolysis, 

volatilization, hydrolysis)

● Low mobility demonstrated in 

column leaching and terrestrial field 

dissipation studies (no detection 

below 17.7 inches)

● Soil adsorption correlates to % OC 

and cation exchange capacity
21

Physical and Environmental Fate Inputs in 

PRZM/EXAMS Model

Parameter

EPA Drinking Water1

and CRLF2

Assessments

Best Available

Value3

Vapor Pressure at 25oC (torr) 1.0 x10-6 (DW)

1.0 x10-3(CRLF)

1.24 x 10-6(MRID 44339601)

Henry’s Law Constant (atm-m3/mol) 9.1 x 10-9 7.40 x 10-9 (calculated from vapor 

pressure and solubility values)

Aerobic Aquatic Half Life (days) 1620

(6x single aerobic soil 

t1/2 value of 270)

237 (90th percent confidence

bound on the mean of 110.4, 

235.8, 38)

Sorption Coefficient, Koc (mL/g) 244 577 (average of 47 values ranging 

from 57 to 3014)

● Some of the environmental fate parameters EPA used in Drinking Water1 and 

CRLF2 assessments to model EECs are not consistent with best available data.

● Biotic degradation in aquatic systems via aerobic metabolism; low mobility

1US EPA 2009. Prometryn (CAS Reg. No. 7287-19-16) Tier I Drinking Water Assessment for the Proposed New Uses on Carrots, Okra, Parsley, 

Cilantro, Celeriac, and Leafy Petioles. Memorandum from Silvia C. Termes to Barbara Madden. June 19, 2009. PC Code: 080805. DP Barcode: 

357096, 357099.

2US EPA 2009. Risk of Prometryn Use to Federally Threatened California Red-legged Frog (Rana aurora draytonii). June 17, 2009.

3Refer to previous slide for data source.
22

Highlight of Updates

● To present the most up to date data, monitoring data presented in 

the slides were updated to include additional sources and up to 

2012 data. The updates were not included in the amended report 

(Assessment Amendment 2, submitted 3/8/13).

- 8 monitoring data sources in PNW and CA (see next slide)

• 10,739 samples; 1,472 sites in PNW and CA*

• 9,054 samples; 1,070 sites within ESU/DPS boundaries*

- No change to the maximum detected concentration reported previously 

(3.13 μg/L within ESU/DPS boundaries, MRID 48541604, 2012, Assessment 

Amendment 2).

*USGS NAWQA not included because majority of NAWQA samples and sites overlap with 

USGW NWIS
23

Sampling Frequency Information for Federal and State 

Surface Water Monitoring Data in WA, OR, CA and ID: 

Updated with up to 2012 data

Source

Number of 

samples 

(sites)

Sites with > 

100 

samples

Sites with > 

25 samples Frequency description

USGS NAWQA 1490 (79) 4 18 Few days apart, weekly, bi-weekly, monthly -

frequency is dependent on the site location

USGS NWIS 2528(330) 6 19

Dependent on site location, ranges from daily, 

weekly, bi-weekly, monthly, several months 

and yearly

EPA STORET 363 (145) 0 0

Irregular, ranges from 1 per site to once per 

month for a few months

CDPR 2278(327) 3 11 Ranges from 2 days, weekly, monthly or 

irregular spaced sampling

CEDEN 1428(306) 0 0

Ranges from 1 to 3 times per year (several 

months apart)

CILRP 329(78) 0 0

Ranges from monthly or 1 to several times per 

year

OR DEQ 795 (143) 0 1

limited sampling per site and irregular 

sampling intervals 

WA EIM 3018(143) 15 18

21 sites have periods of weekly sampling, 16 

of which have multiple years of weekly 

sampling
24

Highlight of updates

● Updated estimated exposure concentrations (EECs) from 

registered crop uses using flowing farm pond scenarios (no 

change from Assessment Amendment 2, submitted 3/8/13).

Parameter Low Flowing Farm Pond 

(504 m3/hr)

Peak 16.1

21-d 6.3

60-d 1.3

Estimated maximum EECs (90th percentile of 30 yearly max. values), μg/L

Note the above concentrations are based on surrogate PRZM crop scenarios in OR 

(static) and WA (flowing) where prometryn crop acreage is minimal and use 

(poundage) is negligible. Furthermore, field location (Grant County) used in the WA 

crop scenario has minimal overlap with ESU/DPSs of concern.

Predicted maximum peak EEC from flowing farm pond is approximately within 5x 

higher than the single maximum concentration (3.13 μg/L) observed in aquatic 

environment from the extensive water monitoring database within the ESU/DPS 

boundaries. 
25

Estimated Exposure from Registered Crop Uses

Hydrologically static water body (farm pond scenario without flow) compared 

with flowing water body (farm pond scenario with low flow)

Parameter Static Farm Pond Low Flowing Farm Pond 

(504 m3/hr)

Peak 68.6 16.1

21-d 67.7 6.3

60-d 66.0 1.3

Estimated maximum EECs (90th percentile of 30 yearly max. values), μg/L

● Conservative exposure estimates using best available inputs

- PRZM/EXAMS with standardized EPA input guidance and scenarios.

- Setbacks required by states, such as California (required setbacks of 60 and 

300 feet for ground and aerial applications, respectively), were not included 

in the calculated exposure values (note: >97% prometryn crop acreage in 

WA, OR, ID, and CA occurs in CA).

- Use of 90th percentile of 30 yearly maximum (peak) concentration in risk 

assessment, corresponding to >99th percentile of 10,957 daily concentration 

values in 30-year period.
26

Estimated Exposure from Registered Crop Uses

● A study by Sommer et al. (2001)* involving the Yolo Bypass, the 

primary floodplain of the lower Sacramento River, California, 

indicated that hydrology affects the quality of floodplain rearing 

habitats. 

● Salmonid growth, survival, feeding success and prey availability 

were greater when the flow-pulses were higher and of longer 

duration. 

● These findings suggest that locations with higher flow-rate are thus 

preferred by salmon, and will positively affect multiple factors that 

influence growth, such as food supply or water temperature. 

*Sommer, T.R., M.L. Nobriga, W.C. Harrell, W. Batham and W.J. Kmmerer. 2001. 

Floodplain rearing of juvenile Chinook salmon: evidence of enhanced growth and 

survival. Can. J. Fish. Aquat. Sci. 58:325-333.
27

Summary

● This presentation contains the most up-to-date monitoring data 

and not all data are included in the amended report.

- No changes to the conclusions that are presented in the current amended 

report.

● Modeling exposure in the flowing water body using static farm 

pond is unrealistic and highly conservative. Hydrologic flow should 

be incorporated in modeling exposure concentrations in flowing 

water bodies.

● Conservative prediction of maximum peak EEC in flowing water 

body (16.1 ug/l) is within 5x of the maximum concentration 

observed in water monitoring data (3.13 ug/l) from flowing water 

bodies within the ESU/DPS boundaries.
28

Ecotoxicology and Potential Risk of 

Prometryn to Salmonids

Detailed information available under Section 10 of the report “Prometryn: Review and 

Assessment of the Potential Impact of Prometryn on Endangered and Threatened Pacific 

Salmonid Species, Assessment Amendment 2” (Pages 52 to 68; Submitted March 8, 2013)
29

Highlight of updates:

Freshwater fish acute endpoint updated

Reasons Beliles et al. (1965) study is not best available data and should 

not be used in assessment. 

• Nominal treatment concentrations only.

• Descriptions of solvent use unclear. 

• Dissolved oxygen, pH, lighting, and photoperiod levels were not reported.

• Water temperatures reached 17.2° C and deviated by ≥4.4° C during the study.

(OPPTS 850.1075 recommends 12 ± 2° C for rainbow trout)

• Only 5 fish per treatment. 

(OPPTS 850.1075 requires a minimum of 7 fish)

Error in Table 15 corrected. 

• The Rainbow Trout 96-h LC50 value for the Hamaker study (1985a) 

should be 5460 μg ai/L (Study recently submitted with amended report).

• This endpoint replaces the Rainbow Trout 96-h LC50 value of 2700 μg ai/L. 

from the Beliles et al. (1965) study. 
30

Direct Effects on Salmonids from Prometryn Use are 

Unlikely

Species Test Material Endpoint (μg a.i./L)

Rainbow Trout Technical 96-h LC50 = 5460

Fathead Minnow Technical 32-d NOEC = 620

Acute RQs ≤ 0.02

Chronic RQ ≤ 0.11

Maximum Modeled Values (μg/L) Maximum Monitoring Values 

(μg/L)

Static Farm Pond Low Flow Farm Pond

Peak 

EEC

60-d 

EEC

Peak EEC 

with flow 

60-d EEC 

with flow CA DPR USGS NAWQA WA EIM

68.6 66.0 16.1 1.3 3.13 0.621 No Detect

TIER 1:
31

Highlight of Changes:

Additional chronic invertebrate endpoint

Marine invertebrate chronic toxicity test with Mysid conducted.

• Study submitted to Agency (3/5/13)

• No Observed Effects Concentration (NOEC) = 110 μg/L (Reproduction)

Daphnid Mysid Chronic NOAEC (μg ai/L)

1

10

100

1000

10000

21-d EEC PRZM/EXAMS - No Flow

21-d EEC PRZM/EXAMS - Flow

Monitoring data maximum 

Static pond

Flowing pond

Monitoring data
32

Indirect Effects to Salmonids via Direct Effects on 

Aquatic Invertebrates are Unlikely

Species Test Material Endpoint (μg a.i./L)

Daphnia magna Technical 48-h EC50 = 18600

Daphnia magna Technical 21-d NOEC = 1000

Americamysis bahia Technical 28-d NOEC = 110 μg/L

Maximum Modeled Values (μg/L) Maximum Monitoring Values 

(μg/L)

Static Farm Pond Low Flow Farm Pond

Peak 

EEC

21-d 

EEC

Peak EEC 

with flow 

21-d EEC 

with flow CA DPR USGS NAWQA WA EIM

68.6 66.0 16.1 1.3 3.13 0.621 No Detect

Acute RQs ≤ 0.01 TIER 1: Chronic RQ ≤ 0.62
33

Highlight of Changes:

Additional aquatic plant endpoints N. pelliculosa S. obliquus S. quadricauda L. gibba C. pyrenoidosa S. vacuolatus L. perpusilla P. subcapitata P. subcapitata Cryptomonas sp. A. flos-aquae S. acutus C. vulgaris C. vulgaris L. minor S. polyrhiza C. pyrenoidosa Lynbya sp. A. flos-aquae Chlorococcum EC50 (μg ai/L)

1

10

100

1000

The GREEN BARS 

represent additional 

endpoints.

Additional values added to Table 17.

The addition of these data is 

useful for assessing 

community-level based effects.
34

0.0

0.2

0.4

0.6

0.8

1.0

0.01 0.1 1 10 100 1000 10000 100000 Proportion of Taxa Affected

Concentration (μg/L)

Add Data Labels & Markers

Highlight of Changes:

Revised aquatic plant SSD

HC20 = 8.4 μg/L
35

Highlight of Changes:

Static Farm Pond - Peak EEC relative to HC20

0.0

0.2

0.4

0.6

0.8

1.0

0.01 0.1 1 10 100 1000 10000 100000 Proportion of Taxa Affected

Concentration (μg/L)

Add Data Labels & Markers

HC20 = 8.4 μg/L

Peak EEC 

(PRZM/EXAM no flow) 

Potential effects 

predicted to 68.5% of 

taxa based on the 

maximum model 

concentration 
36

Highlight of Changes:

Low Flow Farm Pond - Peak EEC relative to HC20

0.0

0.2

0.4

0.6

0.8

1.0

0.01 0.1 1 10 100 1000 10000 100000 Proportion of Taxa Affected

Concentration (μg/L)

Add Data Labels & Markers

HC20 = 8.4 μg/L

Peak EEC 

(PRZM EXAM low flow) 

Potential effects to 

36.5% of taxa based on 

the refined model 

maximum concentration 
37

Highlight of Changes:

Monitoring Data - Peak EEC relative to HC20

0.0

0.2

0.4

0.6

0.8

1.0

0.01 0.1 1 10 100 1000 10000 100000 Proportion of Taxa Affected

Concentration (μg/L)

Add Data Labels & Markers

HC20 = 8.4 μg/L

Max. Measured EEC 

(Monitoring data) 

Potential effects to 

8.5% of taxa based on 

maximum detected 

concentration from 

monitoring data. 
38

Community-level effects are minimal for refined exposure scenarios. 

• Functional redundancy in ecosystems. 

Indirect Effects to Salmonids via Direct Effects on 

Aquatic Plant Communities are Unlikely

Drost et. al (2003)

Aquatic plants rapidly recover from 

prometryn exposure.

• Triazine herbicides target Photosystem II

• Drost et al. (2003) showed that Lemna

minor quickly recovered from ametryn

exposure (based on growth rate). 

Periphyton communities relatively 

insensitvity to prometryn exposure.

• Schmitt-Jansen and Altenburger (2009)

showed that periphyton communities 

exposed to up to 80 μg/L prometryn were 

functionally and structurally similar to 

control treatments.

Control Prometryn

(80 μg/L)

Chl. a

(μg/disk) 1.5 - 2.9 2.14

Species 12 - 18 8

Biodiversity 0.96 - 1.63 0.98

Schmitt-Jansen and Altenburger (2009)
39

Highlight of Changes:

Reanalysis of terrestrial plant endpoints

Inconsistencies among reported Terrestrial Plant Endpoints 

• Canez 1988 – Original study reports (MRIDs 41035903 + 41035904)

• US EPA Data Evaluation Record (1991)

• US EPA California Red-legged Frog Assessment (2009)

• These inconsistencies highlighted in Assessment Amendment 2, Appendix 2 

Re-Analysis of Tier II Terrestrial Plant Toxicity Study Data 

• Seeding emergence

• Vegetative vigor

• Values in Table 24 were updated in Assessment Amendment 2 of the 

Salmonid assessment 

• Calculations appear in Assessment Amendment 2, Appendix 3 
40

0.0

0.2

0.4

0.6

0.8

1.0

0.0001 0.01 1 100 10000 1000000 Proportion of Taxa Affected

Concentration (lbs/A)

Add Data Labels & Markers Add Data Labels & Markers Add Data Labels & Markers Add Data Labels & Markers

HC20 = 0.026 lbs/A

Highlight of Changes:

Revised terrestrial plant SSD (Dry Weight Vegetative Vigor)
41

TerrPlant Screening-Level Model: Exposure Values 

for Terrestrial Plants in Riparian Areas

Application Rate (lb/A) 0.5 0.8 1.0 1.5 1.6 2.0

Runoff Fraction1 0.02 (dry area)

Spray Drift Fraction2 0.01

Runoff Deposition (lb/A)3 0.01 0.016 0.02 0.03 0.032 0.04

Spray Drift Deposition (lb/A)3 0.005 0.008 0.01 0.015 0.016 0.02

Runoff + Drift Deposition (lb/A) 0.015 0.024 0.03 0.045 0.048 0.06

1 Highest result shown in bold font and highlighted

2 TerrPlant model guidance, based on prometryn solubility of 33 mg/L and assuming no soil 

incorporation

3 TerrPlant guidance for ground spray applications

4 Application rate x runoff or spray drift fraction

• Highly conservative exposure estimates
42

0.0

0.2

0.4

0.6

0.8

1.0

0.0001 0.01 1 100 10000 1000000 Proportion of Taxa Affected

Concentration (lbs/A)

Add Data Labels & Markers Add Data Labels & Markers Add Data Labels & Markers Add Data Labels & Markers

HC20 = 0.026 lbs/A

Highlight of Changes:

Tier 1 EEC relative to HC20

Tier 1 Peak EEC 

(TerrPlant Screening-Level)

Potential effects to 29.5% 

of taxa based on the 

model maximum 

concentration 
43

Runoff Refinement Using PRZM Runoff Flux1

Crop Use (PRZM Scenario)

Max. Single 

Applied Rate 

(lb/A)

Number of 

Applications

EEC Contributions (lb/A)

Runoff2 Spray Drift3 Runoff + Drift

Carrots - Fall (CA row crop) 2 2 0.0004 0.02 0.0204

Carrots (ID potato) 2 2 0.0006 0.02 0.0206

Carrots (OR hops) 2 2 0.0007 0.02 0.0207

Carrots - Spring (CA row crop) 2 2 0.0007 0.02 0.0207

Carrots (WA potato) 2 1 0.0014 0.02 0.0214

Celery - Fall (CA row crop) 2 1 0.0004 0.02 0.0204

Celery (OR hops) 2 1 0.0008 0.02 0.0208

Celery (OR snap beans) 2 1 0.0013 0.02 0.0213

Celery - Spring (CA row crop) 2 1 0.0006 0.02 0.0206

Celery (WA onion) 0.8 1 0.0002 0.008 0.0082

Okra - PRE (CA tomato) 1.5 1 0.0014 0.015 0.0164

Okra - PRE + POST (CA tomato) 0.8 2 0.0004 0.008 0.0084

Parsley - Fall (CA lettuce) 0.5 1 0.0007 0.005 0.0057

Parsley - Fall (CA row crop) 2 1 0.0006 0.02 0.0206

Parsley - Spring (CA lettuce) 0.5 1 0.0010 0.005 0.0060

Parsley - Spring (CA row crop) 2 1 0.0006 0.02 0.0206

Rhubarb (OR hops) 2 1 0.0008 0.02 0.0208

Rhubarb (OR snap beans) 2 1 0.0010 0.02 0.0210

Rhubarb (WA onion) 1.6 1 0.0003 0.016 0.0163

1 Highest result shown in bold font and highlighted

2 PRZM edge-of-field runoff flux based on maximum single application rate and maximum number 

of applications per year

3 Spray drift calculation from TerrPlant (1% of application rate)
44

0.0

0.2

0.4

0.6

0.8

1.0

0.0001 0.01 1 100 10000 1000000 Proportion of Taxa Affected

Concentration (lbs/A)

Add Data Labels & Markers Add Data Labels & Markers Add Data Labels & Markers Add Data Labels & Markers

HC20 = 0.026 lbs/A

Highlight of Changes:

Tier 2 EEC relative to HC20

Tier 2 Peak EEC 

(Refined using PRZM Runoff Flux)

Potential effects to 18.5% 

of taxa based on the 

refined model maximum 

concentration 
45

Prometryn Exposure to Wetland Riparian 

Communities is Minimal 

● No significant overlap of prometryn use areas with wetland riparian 

areas based on proximity analysis to site specific crop data

● The proportion (%) of potential crop growing areas registered for 

Prometryn use: 

- Within a 100-ft distance of the wetland locations within the ESU/DPS 

boundaries was extremely low, ranging from 0 to 0.66 % across the 28 

ESU/DPS 

- Within a 100-ft area of the critical habitat streams was extremely low, 

ranging from 0 to 0.43 % across the 21 ESU/DPS (critical habitat spatial data 

available for only 21 ESU/DPS when data was processed)
Image analysis to characterize vegetation changes within riparian zone of the 

critical habitat stream near historical prometryn use areas 

Central Valley Steelhead DPS

Modesto County 

(50M03S07E09)

Total use: 328.5 (a.i. lb)

(94.2lb applied for Dill 

and 234.3lb for Parsley)

Frequency of use:142

Prometryn Use Does Not Adversely Affect Riparian 

Areas Adjacent to Use Sites
Image analysis to characterize vegetation changes within riparian zone of the 

critical habitat stream near historical prometryn use areas 

Prometryn Use Does Not Adversely Affect Riparian 

Areas Adjacent to Use Sites
48

Satellite imagery shows that riparian vegetation areas near sites with 

years of prometryn use are not impacted based on Normalized 

Difference Vegetation Index (NDVI)

Indirect Effects to Salmonids via Direct Effects on 

Terrestrial Plant Communities are Unlikely

Image collected on June, 2001 Image collected on May, 2010

NDVI

Mean = 0.49

SD= 0.14

NDVI

Mean = 0.56

SD= 0.20
49

Toxicity tests were performed with technical prometryn and 

formulated product with species representing various trophic levels. 

TGAI Effects Endpoint 

 (μg ai/L)

100 101 102 103 104 105 106 Formulation Effects Endpoint (μg ai/L) 

100

101

102

103

104

105

106

Green 

algae

Daphnia Carp

Rainbow trout Bluegill

Formulation 

more potent

TGAI 

more potent These data indicate that 

formulated prometryn 

demonstrates toxicity that is 

comparable to TGAI.

Data is shown in Tables 15-17.

Green algae data point is based on a mean 

value from two tests for each test material. 

Comparison of Prometryn Formulations:

Ecotoxicity Endpoints
50

Summary: Update of Risk Assessment

● Direct effects on Salmonids from prometryn exposure are highly 

unlikely

- Updating the freshwater fish acute endpoint did not alter conclusions.

● Indirect effects on Salmonids via direct effects on aquatic 

invertebrates are highly unlikely

- Including the marine invertebrate chronic endpoint did not alter the conclusions.

● Indirect effects on Salmonids via direct effects on aquatic plants are 

unlikely due to the ability of aquatic plants to tolerate and recover 

from prometryn exposure. 

- Including additional aquatic plant endpoints did not alter the conclusions.

- SSD not included in Amended Assessment.

● Indirect effects on Salmonids via direct effects on terrestrial plants 

are likely minimal. 

- Reanalyzing terrestrial plant toxicity endpoints did not alter conclusions.

- SSD not included in Amended Assessment.

● These data indicate that formulated prometryn demonstrates toxicity 

that is comparable to TGAI.
51

Overall Conclusions 

● Current and future potential prometryn use within or adjacent to 

the 28 ESU/DPSs is minimal

● No cotton use within the 28 ESU/DPSs 

- No aerial application

● Monitoring data suggest that aquatic exposure is likely an order of 

magnitude lower than estimated exposure values from standard 

EPA static farm pond scenario

● Incorporating hydrologic flow resulted in markedly lower estimated 

exposure values compared to standard EPA static farm pond 

scenario 

● Potential effects to salmonids from prometryn use is highly 

unlikely

- Direct and indirect 

● There is no indication that prometryn use will jeopardize the 

continuing existence of 28 listed Pacific salmonids or adversely 

affect designated critical habitat for listed Pacific salmonids
52

APPENDIX A: 

Geographic Scope of Prometryn Uses

The analysis has been updated using recent data that has become available since 

the original report was generated. Detailed information available under Section 4 of 

the report “Prometryn: Review and Assessment of the Potential Impact of 

Prometryn on Endangered and Threatened Pacific Salmonid Species, Assessment 

Amendment 2” (Pages 9 to 27; Submitted March 8, 2013)
53

In this section, comprehensive spatial analyses were conducted;

● to understand historical and current prometryn use patterns 

● to identify the area where prometryn registered crops have historically 

grown

● to identify potential prometryn use areas within the 28 salmonid 

ESU/DPSs

Objectives
54

GfK Kynetec Survey Data 

(2006 - 2011)

USGS-NAWQA 

Presenting Use Patterns 

(1999-2004)

Geographic Scope of Historical Prometryn Uses

(Updated with 2011 GfK data)
55

● The California Department of Pesticide Regulation (CDPR) pesticide 

use reporting (PUR) data from the California Pesticide Information 

Portal (CalPIP) [URL: http://www.cdpr.ca.gov/docs/pur/purmain.htm] 

● The latest available information for California pesticide use reports is 

for 2010, and over ten years (2000 – 2010) of PUR data were 

downloaded and summarized. 

Prometryn Uses in California 
The top 150 pesticides by pounds of active ingredients California 

statewide in the most recent available PUR database 2009 & 2010 

 -

 5

 10

 15

 20

 25

 30

 35

 40

 45

Millions

Total Pesticide Use (lb)

- Prometryn is 136th ranked pesticide 

 used in CA both in 2009 and 2010

- Only 0.03 % of total pesticide uses 

in CA both in 2009 and 2010
57

Total Annual Use (lbs) of Prometryn

Reported in CA PUR Database 

(2000 – 2010) 

Updated with 2010 PUR data 

0

50

100

150

200

250

300

350

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Total Uses (Thousand lb per year)

Year 

Total Annual Use
58

Total Annual Use (lbs) of Prometryn per Crop 

Reported in CA PUR Database 

(2000 – 2010)

Updated with 2010 PUR data 

0

50

100

150

200

250

300

350

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

OTHER CROPS

PARSLEY

CELERY

COTTON

Total Uses (Thousand lb per year)

Year 
All Crop Uses 

Prometryn Use Locations 

Relative to the Listed Salmon 

ESU/DPS in CA

80%

20%

Total Prometryn Applications outside ESU/DPS

Total Prometryn Applications within ESU/DPS

Average Annual Use (lbs/yr) 

Reported in CA PUR Database 

(2000 – 2010) 

by Pesticide Use Reporting District
Cotton Only 

Cotton Only 

Prometryn Use Locations 

Relative to the Listed Salmon 

ESU/DPS in CA

100%

Total Prometryn Applications outside ESU/DPS

Total Prometryn Applications within ESU/DPS

Average Annual Use (lbs/yr) Reported 

in CA PUR Database (2000 – 2010) 

by Pesticide Use Reporting District 

No Prometryn uses on Cotton between 

2000 and 2010 in the CA ESU/DPS
Top prometryn labelled crop 

growing counties are Kern, 

Fresno, Kings, Merced, Tulare, 

Madera, Imperial, and 

Riverside counties in CA 

accounting for > 90 % of total 

prometryn registered crop 

acreage in CA, OR, ID, and 

WA.

Total Acreage of All Crops Registered for Prometryn Use

(Average of Reported Acreages from 1997, 2002, and 2007 Agricultural Census)
62

Spatial analysis using crop 

specific location information of 

cropland data layer (CDL) 

showed that the proportion (%) 

of potential prometryn crop area 

within the 28 ESU/DPS 

boundaries are extremely low, 

ranging from 0 to 4 % across 

the 28 ESU/DPS.

All Crop Locations Registered for Prometryn Use

(2007 to 2012 Cropland Data Layer: USDA-NASS)
63

Summary of Comprehensive Spatial Analysis

● Additional data presented that was not included in amended report 

in order to provide the most up-to-date information

● The additional data presented in the current amended report do not 

change the conclusions

● There is minimal potential for prometryn use within the ESU/DPSs 

in Oregon, Washington, and Idaho 

● No prometryn use on cotton within any of the 28 ESU/DPSs

- No aerial use of prometryn within any of the 28 ESU/DPSs

● There is minimal use of prometryn on other specialty crops within 

the 28 ESU/DPSs 

● Overall, the results indicate that current and potential use of 

prometryn within or adjacent to the 28 ESU/DPS in the Pacific 

Northwest and California is minimal
64

APPENDIX B: 

Environmental Fate and Exposure

Monitoring data presented in the slides have been updated using additional data sources and up 

to 2012 data. Detailed information available under Sections 5-8 of the report “Prometryn: Review 

and Assessment of the Potential Impact of Prometryn on Endangered and Threatened Pacific 

Salmonid Species, Assessment Amendment 2” (Pages 32 to 51; Submitted March 8, 2013)
65

Objectives

● To present key environmental fate properties and inputs used in 

exposure modeling.

● To present monitoring data and to understand the behavior of prometryn 

through monitoring data (include additional data sources and 2012 

data).

● To present estimated exposure concentrations from registered crop uses 

using static and flowing farm pond scenarios.
66

Environmental Fate

Parameters Available Data and Source

Aerobic soil t1/2 

(days)

270 

MRID 00148338

Terrestrial field 

dissipation t1/2 

(days)

70, 86, 71, 103

MRIDs 41546401-4, 42253901-4

Aerobic aquatic

t1/2 (days)

110.4, 235.8, 38

MRID 48541603 and EUFOOTPRINT

Koc (mL/g) 57 – 3014 (>47 values)

MRID 41875901, Rao and 

Davidson (1982), Seol and Lee 

(2000), Baskaran and Kennedy 

(1999), Turin and Bowman 

(1997)

Mobility via

column leaching

Low (est. Koc=1228 mL/g)

MRID 41875904

● Major dissipation pathways driven 

by aerobic soil degradation, 

aerobic aquatic degradation, 

sorption.

● No degradation via abiotic pathways 

(e.g. aqueous and soil photolysis, 

volatilization, hydrolysis)

● Low mobility demonstrated in 

column leaching and terrestrial field 

dissipation studies (no detection 

below 17.7 inches)

● Soil adsorption correlates to % OC 

and cation exchange capacity
67

Physical and Environmental Fate Inputs in 

PRZM/EXAMS Model

Parameter

EPA Drinking Water1

and CRLF2

Assessments

Best Available

Value3

Vapor Pressure at 25oC (torr) 1.0 x10-6 (DW)

1.0 x10-3(CRLF)

1.24 x 10-6(MRID 44339601)

Henry’s Law Constant (atm-m3/mol) 9.1 x 10-9 7.40 x 10-9 (calculated from vapor 

pressure and solubility values)

Aerobic Aquatic Half Life (days) 1620

(6x single aerobic soil 

t1/2 value of 270)

237 (90th percent confidence bound 

on the mean of 110.4, 235.8, 38)

Sorption Coefficient, Koc (mL/g) 244 577 (average of 47 values ranging 

from 57 to 3014)

● Some of the environmental fate parameters EPA used in Drinking Water1 and CRLF2

assessments to model EECs are not consistent with best available data.

● Biotic degradation in aquatic systems via aerobic metabolism; low mobility

1US EPA 2009. Prometryn (CAS Reg. No. 7287-19-16) Tier I Drinking Water Assessment for the Proposed New Uses on Carrots, Okra, Parsley, 

Cilantro, Celeriac, and Leafy Petioles. Memorandum from Silvia C. Termes to Barbara Madden. June 19, 2009. PC Code: 080805. DP Barcode: 

357096, 357099.

2US EPA 2009. Risk of Prometryn Use to Federally Threatened California Red-legged Frog (Rana aurora draytonii). June 17, 2009.

3Refer to previous slide for data source.
68

Understanding Prometryn Behavior via Surface 

Water Monitoring Data

● Data from high-frequency sampling locations in or near prometryn use areas in 

the Pacific Northwest and CA suggest stream flow significantly reduces 

prometryn exposure in aquatic systems.

● Predicted concentrations using non-flowing water body assumption do not follow 

the monitoring trends.

Y-axis is relative concentration (C/Cmax), x-axis is years of observed and non site specific simulated 

concentrations
0.0

0.2

0.4

0.6

0.8

1.0

Relative concentration (C/Cmax)

0 1 2 3 4 5 6 7 8

Year

PRZM/EXAMS predicted normalized concentration using low flow (504 

m3/hr) and static versions of EPA farm pond (fall carrots) compared 

with observation at San Joaquin River (Vernalis station)

San Joaquin River Observations

• Monitoring data shows brief periods (~2-3 weeks) of “detects” between longer period of 

“no or low detects” 

• Aquatic degradation t1/2 = 38-236 days, indicating significant contribution of stream 

flow to rapid exposure reduction over 2-3 week period
0.0

0.2

0.4

0.6

0.8

1.0

Relative concentration (C/Cmax)

0 1 2 3 4 5 6 7 8

Year

PRZM/EXAMS predicted normalized concentration using low flow (504 

m3/hr) and static versions of EPA farm pond (fall carrots) compared 

with observation at San Joaquin River (Vernalis station)

No flow farm pond San Joaquin River Observations

• Monitoring data shows brief periods (~2-3 weeks) of “detects” between longer period of 

“no or low detects” 

• Aquatic degradation t1/2 = 38-236 days, indicating significant contribution of stream 

flow to rapid exposure reduction over 2-3 week period

• Static farm pond time series concentration fluctuates with detection throughout 

the years 
0.0

0.2

0.4

0.6

0.8

1.0

Relative concentration (C/Cmax)

0 1 2 3 4 5 6 7 8

Year

PRZM/EXAMS predicted normalized concentration using low flow (504 

m3/hr) and static versions of EPA farm pond (fall carrots) compared 

with observation at San Joaquin River (Vernalis station)

Flowing farm pond (504 m3/hr) No flow farm pond San Joaquin River Observations

• Monitoring data shows brief periods (~2-3 weeks) of “detects” between longer period of 

“no or low detects” 

• Aquatic degradation t1/2 = 38-236 days, indicating significant contribution of stream 

flow to rapid exposure reduction over 2-3 week period

• Static farm pond time series concentration fluctuates with detection throughout the 

years

• Flowing farm pond time series concentrations more closely resemble temporal 

patterns observed in monitoring data
72

Sampling Frequency Information for Federal and State 

Surface Water Monitoring Data in WA, OR, CA and ID: 

Updated with up to 2012 data

Source

Number of 

samples 

(sites)

Sites with > 

100 

samples

Sites with > 

25 samples Frequency description

USGS NAWQA 1490 (79) 4 18 Few days apart, weekly, bi-weekly, monthly -

frequency is dependent on the site location

USGS NWIS 2528(330) 6 19

Dependent on site location, ranges from daily, 

weekly, bi-weekly, monthly, several months 

and yearly

EPA STORET 363 (145) 0 0

Irregular, ranges from 1 per site to once per 

month for a few months

CDPR 2278(327) 3 11 Ranges from 2 days, weekly, monthly or 

irregular spaced sampling

CEDEN 1428(306) 0 0

Ranges from 1 to 3 times per year (several 

months apart)

CILRP 329(78) 0 0

Ranges from monthly or 1 to several times per 

year

OR DEQ 795 (143) 0 1

limited sampling per site and irregular 

sampling intervals 

WA EIM 3018(143) 15 18

21 sites have periods of weekly sampling, 16 

of which have multiple years of weekly 

sampling
Surface Water Monitoring Locations

Updated with up to 2012 data NAWQA

21 years

9637 samples

12.5% detection 

(1203/9637)

Max:3.73 

μg/L(MS); 

95th percentile 

0.19 μg/L 

WA EIM

19 years

3018 samples

No detects

CDPR

13 years

2278 samples

3.7% detection 

(84/2278)

Max. 3.13 μg/L; 

95th percentile 

1.1 μg/L 

OR DEQ

6 years

795 samples

No detects NWIS

23 years

21918 samples

10.6% 

detection 

(2322/21918)

Max. 3.73 μg/L 

(MS); 

95th percentile 

0.2 μg/L 

EPA STORET

25 years

6626 samples

5.4% detection 

(358/6626)

Max. 1.82 μg/L 

(MS); 

95th percentile 

0.257 μg/L 

CEDEN

10 years

1428 samples

1.4% detection 

(20/1428)

Max. 0.013 

μg/L; 95th

percentile 

0.013μg/L 

CILRP

5 years

329 samples

0.6% detection 

(2/329)

Max. 1.1 μg/L
Surface Water Monitoring Locations in PNW and CA

Updated with up to 2012 data

NAWQA

21 years, 4 sites with > 

100 samples

ESU/DPS boundaries: 

74 sites, 1351 samples, 

max. 0.621 μg/L, 

95th percentile 0.126 μg/L 

WA EIM

19 years, 15 sites with > 

100 samples

ESU/DPS boundaries: 

94 sites, 2896 samples, 

no detects

CDPR

13 years, 3 sites with > 

100 samples

ESU/DPS boundaries: 

237sites, 1849 samples, 

max. 3.13 μg/L, 

95th percentile 0.51μg/L 

OR DEQ

6 years, 0 site with > 100 

samples

ESU/DPS boundaries: 

113 sites, 690 samples, 

no detects

NWIS

23 years, 6 sites with > 

100 samples

ESU/DPS boundaries: 

243 sites, 2209 samples, 

max. 1.4 μg/L, 

95th percentile 0.2 μg/L 

CEDEN

10 years, 0 sites with > 

100 samples

ESU/DPS boundaries: 

214 sites, 970 samples, 

max. 0.005 μg/L, 

95th percentile 0.005 μg/L 

EPA STORET

25 years, 0 sites with > 

100 samples

ESU/DPS boundaries: 

134 sites, 297 samples, 

max. 0.236 μg/L, 

95th percentile 0.236 μg/L 

CILRP

5 years, 0 sites with > 100 

samples

ESU/DPS boundaries: 

35 sites, 143 samples, 

No detects
Surface Water Monitoring Locations in 

California

Max detection 

location: Orestimba

Creek at River Road

CA DPR: max 3.13 

μg/L, 95th percentile 

1.1μg/L 

NAWQA: max 0.621 μg/L, 

95th percentile 0.126 μg/L 

NWIS: max1.4 μg/L, 95th

percentile 0.285 μg/L 

EPA STORET: : max 

0.236 μg/L, 95th

percentile 0.236 μg/L 

CEDEN : max 0.013 μg/L, 

95th percentile 0.013 

μg/L 

CILRP: max 1.1 μg/L 
76

Summary

● This presentation contains the most up-to-date monitoring data 

and not all data are included in the amended report.

- No changes to the conclusions that are presented in the current amended 

report.

● Predicted concentrations using non-flowing water body assumption do not follow 

the monitoring trends.

● Modeling exposure in the flowing water body using static farm pond is unrealistic 

and highly conservative. Hydrologic flow should be incorporated in modeling 

exposure concentrations in flowing water bodies.

● Conservative prediction of maximum peak EEC in flowing water body is 

within 5x of maximum concentration observed in water monitoring data 

from flowing water bodies within the ESU/DPS boundaries.
77

APPENDIX C:

Formulations information

Detailed information available under Section 9 of the report “Prometryn: Review and 

Assessment of the Potential Impact of Prometryn on Endangered and Threatened Pacific 

Salmonid Species, Assessment Amendment 2” (Pages 51 to 52; Submitted March 8, 2013)
78

Comparison of Prometryn Formulations

Component Caparol 4L A3593F1 Suprend2 A1114U1

Prometryn X X X X

Trifloxysulfuron X

Surfactant A X

Surfactant B X

Surfactant C X

Surfactant D X X

Surfactant E X

Surfactant F X

Dispersing Agent 1 X

Dispersing Agent 2 X

Dispersing Agent 3 X

Antifreeze 1 X

Antifreeze 2 X

Antifreeze 3 X

Antifoam X X

Thickener X X

Biocide X X

Encapsulating Agent X

Diluent 1 X X

Diluent 2 X

Formulations used in 

ecotoxicity studies are similar 

to the 2 products registered 

and can be used as surrogate 

data to represent the general 

ecotoxicity of products 

formulated with prometryn.

X indicates component is present in 

formulation

Green blocks represent same (or 

chemically & functionally equivalent) 

components present in more than 1 

formulation

1 Ecotoxicity studies conducted on these formulations

2 Registered on cotton only