Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A

Data Requirement:

EPA MRID Number 47748202

PMRA Data Code:

EPA DP Barcode: None given

OECD Data Point:

EPA Guideline: OPPTS 850.4225 (l23-la)

Test material:

Common name:

Chemical name:

Tribenuron methyl 50SG (AI: Tribenuron methyl) Purity: 52.3% (w/w)

Tribenuron methyl

IUPAC: methyl 2-[4-methoxy-6-methyl-1 ,3,5-triazin-2-yl(methy1)carbamoylsulfamoyl]benzoate

CAS name: methyl 2-[[[[(4-methoxy-6-methyl-1 ,3,5-triazin-2-

yl)methylamino]carbonyl]amino]sulfonyl]benzoate

CAS No.: 101200-48-0 (a.i.)

Synonyms: DPX-L5300, DPX-L5300-255 water soluble granular formulation, DPX-L5300-255,

Tribenuron methyl 50SG

Primary Reviewer: Moncie Wright

Staff Scientist, Cambridge Environmental, Inc.

Secondary Reviewer: Teri S. Myers

Senior Scientist, Cambridge Environmental, Inc.

Primary Reviewer: Christina Wendel

USEPA/OCSPP/OPP/ERBIIIBiologist

Secondary Reviewer(s): Kristina Garber

USEPA/OCSPP/OPP/ERBII/Biologist

Reference/Submission No.: {. }

Signature: 1YltPIt&i VfIJ.ujItt

Date: 07/27/09

,,'5

Signature:

Date: 0911 1/09

Signature: ~~~uJ,~ Date: CJ.tlOS/iI /

Signature:

Date: / I

W~r;"/II

Company Code

Active Code

Use Site Category:

EPA PC Code

{ }

{ }

{ }

128887

[For PMRA]

[For PMRA]

[ForPMRA]

Date Evaluation Completed: 05-04-2011

CITATION: Porch, l.R. and K.H. Martin. 2009. Tribenuron Methyl (DPX-L5300) 50SG: A Greenhouse Study to

Investigate the Effects on Seedling Emergence and Growth of Two Sensitive Terrestrial Plants Following Soil

Exposure. Unpublished study performed by Wildlife International, Ltd., Easton, Maryland. Laboratory Study

Number: 112-623. Study sponsored by E.I. du Pont de Nemours and Company, Wilmington, Delaware. DuPont

Study Number: DuPont-25762. Study completed April 8, 2009.

Page 1 of 14

/.11••1111

2086540

TEXT SEARCHABLE DCOUMENT 2011
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A

EXECUTIVE SUMMARY:

EPA MRID Number 47748202

The effect of Tribenuron methyl50SG (formulation containing the active ingredient Tribenuron methyl) on the

seedling emergence of mono cot (onion, Allium cepa) and dicot (sugarbeet, Beta vulgaris) crops was studied at

nominal application rates of 0 (negative and surfactant controls), 0.137, 0.273, 0.547, 1.09,2.19, 4.38, 8.75, and

17.5 g a.i./ha, which were equivalent to 0 (negative and surfactant control), 0.000122, 0.000242, 0.000486,

0.000968,0.00194,0.00389,0.00777, and 0.01551bs a.i.lA.

The growth medium used in the seedling emergence test was a natural soil classified as a sandy loam with an organic

carbon content of 0.8% and a pH of 6.1. On Day 21 the surviving plants per pot were recorded and cut at soil level

for measuring the height and dry weight.

Sugarbeet survival on day 21 was 92% and 86% in the negative and surfactant controls, respectively. There was no

inhibition in survival for sugarbeet. Percent emergence was 75% and 65% on day 7, and was 78% and 65% on day

21 in the negative and surfactant controls, respectively. Inhibition for sugarbeet emergence was at a maximum of

17% on day 7, and 10% on day 21 in the 0.00777lbs ai/A treatment group, respectively. Inhibitions in sugarbeet

plant height ranged from 0% to 18% in the treatment groups, and was 2% in the surfactant control. Inhibitions in

sugarbeet dry weight ranged from -17% to 33% in the treatment groups, and was -17% (positive growth) in the

surfactant control. Sugarbeet exhibited signs oftoxicity such as chlorosis, mortality, stem curl and necrosis.

Although toxicity was variable and scattered, there is concern about the impact ofthe surfactant control on the results

seen.

Onion survival on day 21 was 97% and 100% in the negative and surfactant controls, respectively. There was no

inhibition in survival for onion. Percent emergence was 30 and 8% on day 7, and 78% and 63% on day 21 in the

negative and surfactant controls, respectively. Inhibition for onion emergence was at a maximum of 42 % in the

0.0004861bs ai/A treatment group on day 7, and 19% in the 0.000242 lbs ai/A treatment group on day 21.

Inhibitions in onion plant height ranged from -1% to 20%, in the treatment groups, and was 30% in the surfactant

control. Inhibitions in onion dry weight ranged from 0% to 36% in the treatment groups, and was 36% in the

surfactant control. Onion exhibited signs oftoxicity such as mortality, stem curl and necrosis. Although toxicity was

variable, there is concern about the impact ofthe surfactant control on the effects seen, as there was a 36% inhibition

on onion dry weight, and a 30% inhibition on onion height.

There was no indication of a dose-response relationship for any endpoint of any species tested. However, this lack

of dose-response may be related to the affect ofthe surfactant on the species tested. There is a large variability

within this data, and as a result a definitive response curve could not be conceived from the available data. The high

variability precluded the ability ofthe t-test to detect a significant difference, and the possibility that the surfactant

may have impacted onion and sugarbeet yield responses cannot be ruled out. This possible surfactant effect makes it

difficult to conclude that there is no chemical effect. This uncertainty in the data, especially in regards to the

surfactant control effect, is too great to discount, and therefore the study is not reliable or usable in risk assessment.

This study is classified as invalid, and does not satisfy guideline requirement for a Tier II terrestrial plant seedling

emergence toxicity study. The high variability precluded the ability ofthe t-test to detect a significant difference,

and the possibility that the surfactant may have impacted onion and sugarbeet yield responses cannot be ruled out. In

addition the study author's failed to test up to the highest single application rate and failed to capture an Ee2s. It is

the combination of high variability within the data set, the inhibition effects observed in the surfactant control as

compared to the negative control, and the failure to test up to the highest single application rate registered for the

chemical that result in this study being classified as unacceptable for use in risk assessment. Therefore, a new study

is required.

Page 2 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methylSOSG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

Maximum Labeled Rate: The maximum single application rate ofthis chemical is 0.03 ]25 Ibs a.i./A, which is

greater than the maximum application rate that was used in this study.

I. MATERIALS AND METHODS

GUIDELINE FOLLOWED: This study was conducted following guidelines outlined in the U.S.

Environmental Protection Agency Series 850 Ecological Effects Test

Guidelines (Draft), OPPTS 850.4100 and 850.4225 (Tiers I and II), U.S.

EPA Pesticide Assessment, Subdivision J, Hazard Evaluation: Nontarget

Plants, Series 122-1 and ]23-1, and OECD Guideline 208, Seedling

Emergence and Seedling Growth Test. Deviations from OPPTS 850.4225

were noted:

• The physicochemical properties of the test material were not reported.

• The study author's failed to test up to the highest single application rate that is registered to the

chemical (0.0313 Ibs ailA), and failed to capture an EC2s.

These deviations do impact the acceptability ofthe study.

COMPLIANCE:

A. MATERIALS:

1. Test Material

Description:

Lot No./Batch No. :

Purity:

Stability of compound

under test conditions:

Storage conditions of

test chemicals:

Signed and dated No Data Confidentiality, GLP and Quality Assurance

statements were provided. This study was conducted in compliance with the

Good Laboratory Practice Standards as published by the U.S. EPA, FIFRA

(40 CFR, Part 160; ]989), which are consistent with the OECD Principles of

GLP (ENV/MC/CHEM(98)] 7; 1998) and Japan MAFF (I 1 NohSan,

Notification No. 6283; 1999) with the following exception:

Periodic soil and water screening analyses were not performed according to

GLP standards. These tests were performed using standard EPA procedures

and a certified laboratory.

Tribenuron methyl (DPX-L5300) 50SG (formulation containing Tribenuron

methyl)

Not reported

MAY07EL003

52.3% (w/w)

Analytical recoveries of the primary stock solution following solution

preparation were 97% of nominal test concentrations. (DEeD recommends

chemical stability in water and light)

Not reported

Page 3 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

Table 2. Physical/chemical properties of Tribenuron methyl 50SG (AI: Tribenuron methyl).

Parameter Values Comments

Water solubility at 20EC Not Reported

Vapor pressure Not Reported

UV absorption Not Reported

pKa Not Reported

Kow Not Reported

2. Test organism:

Monocotyledonous species: Onion (Allium cepa, Family Liliaceae; WI-30t); EPA recommendsfour

monocots in two families, including corn.

Dicotyledonous species: Sugarbeet (Beta vulgaris, Family Chenopodiaceae; none given); EPA

recommends six dicots infourfamilies, including soybean and a root crop.

DECD recommends a minimum ofthree species selectedfor testing, at least onefrom each ofthe following categories:

Category 1: ryegrass, rice, oat, wheat, and sorghum; Category 2: mustard, rape, radish. turnip, and Chinese cabbage;

Category 3: vetch. mung bean. red clover, fenugreek, lettuce, and cress.

Seed source: Onion obtained from Wannamaker Seeds, St. Matthews, SC (lot no. WS06-02); and sugarbeet

obtained from Betaseed, Inc., Shakopee, MN (lot no. 7073).

Prior seed treatment/sterilization: None reported

Historical % germination ofseed: Onion, >85%; and sugarbeet, 90%

Seed storage, if any: Not reported.

B. STUDY DESIGN:

1. Experimental Conditions

a. Limit test: N/A- test was conducted under Tier II conditions.

b. Range-finding study: No range-finding data were provided.

c. Definitive Study

Page 4 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

Table 3: Experimental Parameters - Seedling Emergence.

Parameters Seedling Emergence

Details Remarks

Criteria

Duration ofthe test

Number of

seeds/plants/species/

replicate

Number ofreplicates

Control:

Adjuvant control:

Treated:

Test concentrations

Nominal (reported):

Nominal (reviewerconverted):

Method and interval of

analytical verification

LOQ:

LOD:

Adjuvant (type,

percentage, if used)

21 Days

10 seeds per replicate pot

4

4

4/level

o(negative and surfactant

controls), 0.137,0.273,0.547,

1.09,2.19,4.38,8.75, and 17.5 g

ai/ha

o(negative and surfactant control),

0.000122, 0.000242, 0.000486,

0.000968,0.00194,0.00389,

0.00777, and 0.0155 lbs ai/A

Samples from the primary stock

solution were analyzed after

solution preparation using HPLC

with UV (254 nm) detection.

Not reported

Set at the lowest analytical standard

analyzed

Tween 80 non-ionic surfactant,

0.25% (v/v)

Page 5 of 14

Recommended test duration is 14-21 days.

DECD recommends that the test be terminated no

sooner than 14 days after 50 percent ofthe control

seedlings have emerged

Ten seeds per replicate should be used.

DECD recommends a minimum offive seeds planted

in each replicate within 24 hours ofincorporation

ofthe test substance. All seeds ofeach species for

each test should be ofthe same size class. The seed

should not be imbibed.

Four replicates per dose should be used.

DECD recommends a minimum offour replicates

per treatment

Five test concentrations should be used with a dose

range of2X or 3Xprogression

DECD recommends three concentrations.

preferably with application rates equivalent to 0.0

(control), 1.0. 10.0 and 100 mg substance per kg of

oven-dried soil.
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

Parameters Seedling Emergence

Details Remarks

--------------------------------~-----------------

Criteria

Test container (pot)

-------------------------------------------------- SizeNolume 16 em diameter; 12 em depth Non-porous containers should be used.

Material: Plastic

(glass/polystyrene) OECD recommends that non-porous plastic or

glazed pot be used.

Growth facility Greenhouse

Method/depth ofseeding A template was used to prepare 10

holes ofsimilar size and depth in

the soil surface, and then the seeds

were placed in each hole and

closed by depressing the soil

surface. Sugarbeet and onion were

planted at ca. 6 mm depth.

Test material application Sprayer was calibrated to apply approx. 400L

Application time including Test material was applied to the water/ha at approx. 2.8 bar (40 psi)

the plant growth stage soil surface on Day O.

Number of application Single application

Application interval N/A

Method of application Automated laboratory track sprayer

equipped with a Teejet 8002E

spray nozzle.

Details ofsoil used Organic matter content: 1.3%

Geographic location Sandy loam (non-sterile, natural pH (CaCIz): 5.8

topsoil) obtained from Chris Lee Bulk density: 1.32 g/cm"

and Son, Inc., Easton, MD; Potassium: 58 ppm

geographic location not reported Magnesium: 85 ppm

Depth ofsoil collection Not reported Calcium: 744 ppm

Soil texture Sandy loam Sodium: 17 ppm

% sand 57% --------------------------------------------------

% silt 27% Soil mixes containing sandy loam. loam, or clay

% clay 16% loam soil with no greater than 2% organic matter

are preferable. Glass beads, rock wool, and 100% pH: 6.1 (water) acid washed sand are not preferred. % organic carbon 0.8%

CEC 7.4 meq/lOO g OECD prefers the soil to be sieved (0.5 em) to

Moisture at 1/3 atm (%) 14.4% remove coarse fragments. Carbon content should

not exceed 1.5% (3% organic matter). Fine particles

(under 20um) makeup should be between 10 and

20%. The recommendedpH is between 5.0 and 7.5.

Page 6 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

Parameters Seedling Emergence

Details Remarks

--------------------------------------------------

Criteria

Details of nutrient medium, N/A; a nutrient medium was not

if used used

Watering regime and Water characterization:

schedules pH: 8.1

Water source/type: Domestic well water Dissolved oxygen: 8.1 ppm

Volume applied: Not reported Conductivity: 371 umhos/cm

Interval of application: Every 2 to 5 days Temperature: 18.2°C

Method of application: All pots were top-watered after Alkalinity: 182 mg/L as CaC03

application to ensure movement of Hardness: 140 mg/L as CaC03

the test material into the soil. --------------------------------------------------

Thereafter, seedlings were sub- EPA prefers that bottom watering be utilizedfor

seedling emergence studies so that the chemical is irrigated. not leached out ofthe soil during the test.

Any pest control None reported

method/fertilization, if

used

Test conditions Greenhouse

Temperature: 18.9-34.0°C

Photoperiod: 16L:80 --------------------------------------------------

EPA prefers that the cold vs warm loving plants be Light intensity and quality: Moles PAR: 8.3-19.0 tested in two separate groups to optimize plant Natural daylight supplemented by growth.

artificial lighting (high pressure

sodium lamps) DEeD prefers that the temperature. humidity and

light conditions be suitable for maintaining normal

Relative humidity: 23.3-93.0% growth ofeach species for the test period.

Reference chemical

(if used) N/A A reference chemical was not used.

Name:

Concentrations:

Other parameters, if any None

Page 7 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

2. Observations:

a e : servafIOn Parameters - Seeau109 Emergence.

Parameters Seedling Emergence

Details Remarks

Parameters measured (e.g., number -Emergence

of germinated seeds, emerged -Survival

seedlings, plant height, dry weight -Height

or other endpoints) -Dry Weight

-Phytotoxicity

Measurement technique for each Emergence, survival, and

parameter phytotoxicity were

determined by visual

assessment. Height

determination methods

were not reported. Dry

weight was determined by

drying the plant material

in an oven at 80°C for at

least 48 hours, cooling to

room temperature, and

weighing.

Observation intervals Emergence, survival, and

phytotoxicity were

assessed on Days 7, 14

and 21. Dry weight and

height were assessed at

study termination.

Other observations, if any None reported

Were raw data included? Yes

Phytotoxicity rating system, if used o= no effect; 10 = effects

at the threshold of visual

detection; 100 = complete

mortality or defoliation

Percent visual response is

presented in the statistical

output and report tables as

0% = plant death and

100% = no visual

response.

T bl 4 Ob

Page 8 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A

II. RESULTS and DISCUSSION:

A. INHIBITORY EFFECTS:

1. Seedling Emergence:

EPA MRID Number 47748202

Sugarbeet survival was 92% and 86% in the negative and surfactant controls, respectively. There was no

inhibition in survival for sugarbeet. Emergence was 78% and 65% in the negative and surfactant controls,

respectively. Inhibition for sugarbeet emergence was at a maximum of 10% in the 0.00777 Ibs ai/A

treatment group.

Inhibitions in sugarbeet plant height were relatively low, ranging from 0% to 18%. Inhibitions in sugarbeet

dry weight were moderate, ranging from -17% to 33%. Sugarbeet exhibited signs oftoxicity such as

chlorosis, mortality, stem, curl and necrosis. Although toxicity was variable and scattered, there is concern

about the impact ofthe surfactant control on the results seen.

Onion survival was 97% and 100% in the negative and surfactant controls, respectively. There was no

inhibition in survival for onion. Emergence was 78% and 63% in the negative and surfactant controls,

respectively. Inhibition for onion emergence was at a maximum of 19% in the 0.000242 Ibs ai/A treatment

group.

Inhibitions in onion plant height were relatively low, ranging from -1% to 20%. Inhibitions in onion dry

weight were moderate, ranging from 0% to 36%. Onion exhibited signs oftoxicity such as mortality, stem,

curl and necrosis. Although toxicity was variable and scattered, there is concern about the impact ofthe

surfactant control on the results seen.

The most sensitive monocot and dicot species were determined during Tier I testing, and this study was

conducted in order to determine toxicity values for onion and sugarbeet.

All sugarbeet endpoints had reported NOAEC, EC25, and EC50 values of 17.5, >17.5, and> 17.5 g ai/ha,

respectively, which were equivalent to 0.0155, >0.0155, and >0.0155 Ibs ailA, respectively.

All onion endpoints had reported NOAEC, ECz5, and EC50 values of 17.5, >17.5, and>17.5 g ai/ha,

respectively, which were equivalent to 0.0155, >0.0155, and >0.0155 Ibs ai/A, respectively.

B. REPORTED STATISTICS:

Mean dry weight, shoot height, emergence, and survival ofthe controls and treatment groups were compared.

The NOAEC was determined using a Jonckheere-Terpstra trend test (a=0.05). The ECx values and their 95%

confidence limits were determined by non-linear regression analysis ofthe biological response versus the

nominal application rate using SAS Version 8. The study authors analysis detected significant differences

(p<0.05) between biomass means for the negative and surfactant control groups, but did not detect differences

between the treatment groups and the negative, surfactant, or pooled controls. The study authors reported that

because no other endpoint showed differences between the control groups, control responses were pooled for

comparison to treatment.

C. VERIFICATION OF STATISTICAL RESULTS BY THE REVIEWER:

Statistical Method(s): Any species exhibiting an inhibition of::>:5% relative to the negative control based on %

Page 9 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

emergence, % survival, dry weight or height was statistically analyzed. The toxicity values were visually

determined when inhibitions did not exceed 5% for a given endpoint. All analyses were conducted using the

negative control only. The negative and surfactant controls were compared using a t-test in Toxstat or in Excel.

Following the t-test, the reviewer tested each data set for normality using the Chi-square and Shapiro-Wilks tests

and for homogeneity of variance using the Hartley and Bartlett's tests. If the data met these assumptions of

ANOYA, the NOAEC value was determined using the parametric Dunnett's test (ofBonferonni's test for

unequal replicates) and Williams' test. If the data did not meet these assumptions, the NOAEC value was

determined using the non-parametric Kruskal- Wallis test. In all cases, the reviewer also compared the doseresponse pattern (as determined by the % inhibitions) to the output ofthe statistical tests to determine if

biological significance existed in the absence ofstatistical significance. These analyses were conducted using

Toxstat statistical software. The reviewer then attempted to determine the ECx values, 95% confidence intervals

and slopes using the probit analysis via Nuthatch statistical software. All analyses were conducted using the

nominal application rates ofthe active ingredient.

D. STUDY DEFICIENCIES:

A t-test conducted on onion dry weight data detected a significant reduction (36%, p<0.05) in the surfactant

control group, relative to the negative control group. Further, while the t-test conducted for onion height did not

detect a significant difference between the negative and surfactant controls, there was a 30% inhibition in the

surfactant control as compared to the negative control. High variability precluded the ability ofthe t-test to

detect a significant difference, but the possibility that the surfactant may have impacted onion yield responses

cannot be ruled out. For sugarbeet dry weight, although not a significant difference, there was a -17% inhibition

(positive growth) in the surfactant control as compared to the negative control. High variability precluded the

ability ofthe t-test to detect a significant difference, but the possibility that the surfactant may have impacted the

surgarbeet yield cannot be ruled out. Control group differences were not detected for the other endpoints. In

addition to the surfactant effect that was observed, the study author's failed to test up to the highest single

application rate that is registered to the chemical (0.0313 Ibs ailA), and failed to capture an EC25.

E. REVIEWER'S COMMENTS:

The reviewer could not definitively calculate ECx values for either onion or sugarbeet endpoints. The maximum

single application rate that is registered for this chemical is 0.0313 Ibs ai/A, which is greater than the highest

concentration that was tested (0.0155 Iba ai/A). It was determined that there was a potential interaction ofthe

surfactant control on both species, in addition to the large variability ofthe data, that confounded the results.

The combination ofthese two factors precluded the ability to detect a significant difference even if one was

present. The data available within this study cannot be used, and a new study is required.

The in-life phase ofthe test with onion, ryegrass, wheat, corn, and carrot was conducted from January 20 to

February 10,2009. The in-life phase ofthe test with sugarbeet, cabbage, soybean, lettuce, and tomato was

conducted from January 22 to February 12,2009.

F. CONCLUSIONS:

This study is classified as invalid, and does not satisfy guideline requirement for a Tier II terrestrial plant

seedling emergence toxicity study. High variability precluded the ability ofthe t-test to detect a significant

difference, and the possibility that the surfactant may have impacted onion and sugarbeet yield responses cannot

be ruled out. It is the combination of high variability within the data set, the inhibition effects observed in the

surfactant control as compared to the negative control, and the failure to test up to the highest single application

rate registered for the chemical that result in this study being classified as unacceptable for use in risk

assessment.

Page 10 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A

III. REFERENCES:

EPA MRID Number 47748202

U.S. Environmental Protection Agency, Series 850- Ecological Effects Test Guidelines (draft), OPPTS Number

850.4100: Terrestrial Plant Toxicity, Tier I (Seedling Emergence). 1996.

U.S. Environmental Protection Agency, Series 850- Ecological Effects Test Guidelines (draft), OPPTS Number

850.4225: Terrestrial Plant Toxicity, Tier II (Seedling Emergence). 1996.

Bruce, Robert D. and Donald J. Versteeg. 1992. A Statistical Procedure for Modeling Continuous Toxicity Data.

Environmental Toxicology and Chemistry. 11: 1485-1494.

U.S. Environmental Protection Agency, "Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation:

Nontarget Plants, Series 122-1 and 123-1", 22 October 1982.

OECD, OECD Guideline for the Testing of Chemicals, Guideline 208, Terrestrial Plant Test: Seedling Emergence

and Seedling Growth Test. July 2006.

Frans, R.E. and Talbert, R.E., Design ofField Experiments and the Measurement and Analysis of Plant Responses.

Pages 15-23 in B. Truelove, ed. Research Methods in Weed Science. Southern Weed Science Society, Auburn

University, Alabama, 1977.

SAS Institute, Inc. 1999. SAS/STAT User's Guide, Version 8. SAS Institute, Inc., Cary, NC.

Page 11 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A EPA MRID Number 47748202

APPENDIX I. OUTPUT OF REVIEWER'S STATISTICAL VERIFICATION:

Table 1

as lbs a.i./A as lbs a.i./A

Onion Weight Mean SO %Inhibition Sugarbeet Weight Mean SO %Inhibition

Neg control 0.011 0.002309 N/A Neg control 0.046 0.029 N/A

Surfactant control 0.007 0.0015 36 Surfactant control 0.054 0.021 -17

0.000122 0.007 0.001291 36 0.000122 0.036 0.008 22

0.000242 0.009 0.003202 18 0.000242 0.04 0.014 13

0.000486 0.008 0.000816 27 0.000486 0.054 0.03 -17

0.000968 0.01 0.000816 9 0.000968 0.042 0.014 9

0.00194 0.01 0.00263 9 0.00194 0.037 0.015 20

0.00389 0.01 0.001915 9 0.00389 0.031 0.005 33

0.00777 0.011 0.002217 0 0.00777 0.044 0.006 4

0.0155 0.008 0.0015 27 0.0155 0.047 0.03 -2

as lbs a.i./A as lbs a.i./A

Onion Height Mean SO %Inhibition Sugarbeet Height Mean SO %Inhibition

Neg control 9.0 1.576 N/A Neg control 8.1 1.972 N/A

Surfactant control6.3 1.879 30 Surfactant control 7.9 0.974 2

0.000122 7.7 0.419 14 0.000122 7.1 0.686 13

0.000242 7.2 1.234 20 0.000242 7.3 0.850 10

0.000486 7.6 0.877 16 0.000486 8.1 1.132 0

0.000968 8.7 0.574 3 0.000968 7.5 0.206 8

0.00194 8.9 0.594 1 0.00194 6.7 0.500 18

0.00389 7.8 0.532 13 0.00389 6.8 0.507 16

0.00777 9.1 1.159 -1 0.00777 7.4 0.789 9

0.0155 8.6 1.252 4 0.0155 7.8 1.907 4

( -) : indicates positive growth

Tribenuron methyl & onion 21-day % emergence; lbs ai/A

File: 84020e Transform: NO TRANSFORMATION

t-test of Surfactant and Blank Controls Ho:GRP1 MEAN = GRP2 MEAN

GRP1 (SURFACTANT CRTL) MEAN

GRP2 (BLANK CRTL) MEAN

DIFFERENCE IN MEANS

77.5000 CALCULATED t VALUE

62.5000 DEGREES OF FREEDOM =

15.0000

6

1.6859

TABLE t VALUE (0.05 (2), 6) 2.447

TABLE t VALUE (0.01 (2), 6) = 3.707

NO significant difference at alpha=0.05

NO significant difference at alpha=O.Ol

Tribenuron methyl & sugarbeet 21-day % emergence lIb/A)

File: 8402se Transform: NO TRANSFORM

t-test of Surfactant and Blank Controls Ho:GRP1 MEAN = GRP2 MEAN

GRP1 (SURFACTANT CRTL) MEAN

GRP2 (BLANK CRTL) MEAN

DIFFERENCE IN MEANS

77.5000 CALCULATED t VALUE

65.0000 DEGREES OF FREEDOM =

12.5000

6

0.8885

TABLE t VALUE (0.05 (2), 6) 2.447

TABLE t VALUE (0.01 (2), 6) = 3.707

NO significant difference at alpha=0.05

NO significant difference at alpha=O.Ol

Page 12 of 14
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A

Onion Survival

Mean

Variance

Observations

Hypothesized Mean Difference

df

t Stat

P(T<=t) one-tail

t Critical one-tail

P(T<=t) two-tail

t Critical two-tail

Sugarbeet Survival

Mean

Variance

Observations

Hypothesized Mean Difference

df

t Stat

P(T<=t) one-tail

t Critical one-tail

P(T<=t) two-tail

t Critical two-tail

Neg control

97

36

4

o

3

-1

0.195501109

2.353363435

0.391002218

3.182446305

Neg control

92.25

93.58333333

4

o

6

0.878953192

0.206619244

1.943180274

0.413238488

2.446911846

Solvcontrol

100

o

4

Solv control

86

108.6666667

4

EPA MRID Number 47748202

Tribenuron methyl & onion dry weight per plant (g) ;lb/A

File: 84020w Transform: NO TRANSFORM

t-test of Surfactant and Blank Controls Ho:GRP1 MEAN = GRP2 MEAN

GRP1 (SURFACTANT CRTL) MEAN

GRP2 (BLANK CRTL) MEAN

DIFFERENCE IN MEANS

11.0000 CALCULATED t VALUE

6.7500 DEGREES OF FREEDOM =

4.2500

6

3.0867

TABLE t VALUE (0.05 (2), 6) = 2.447** SIGNIFICANT DIFFERENCE at alpha=0.05

TABLE t VALUE (0.01 (2), 6) = 3.707 NO significant difference at alpha=O.Ol

Tribenuron methyl & sugarbeet weight per plant (g) ;lb/A

File: 8402sw Transform: NO TRANSFORM

t-test of Surfactant and Blank Controls Ho:GRP1 MEAN = GRP2 MEAN

GRP1 (SURFACTANT CRTL) MEAN

GRP2 (BLANK CRTL) MEAN

DIFFERENCE IN MEANS

46.2500 CALCULATED t VALUE

53.5000 DEGREES OF FREEDOM =

-7.2500

6

-0.4045

TABLE t VALUE (0.05 (2), 6) = 2.447

TABLE t VALUE (0.01 (2), 6) = 3.707

NO significant difference at alpha=0.05

NO significant difference at alpha=O.Ol

Tribenuron methyl & onion height (em); lbs ai/A

File: 84020h Transform: NO TRANSFORM

t-test of Surfactant and Blank Controls Ho:GRP1 MEAN = GRP2 MEAN

GRP1 (SURFACTANT CRTL) MEAN

GRP2 (BLANK CRTL) MEAN

DIFFERENCE IN MEANS

8.9750 CALCULATED t VALUE

6.2500 DEGREES OF FREEDOM =

2.7250

Page 13 of 14

6

2.2226
Data Evaluation Report on the Acute Toxicity of Tribenuron methyl 50SG (AI: Tribenuron

methyl) to Terrestrial Vascular Plants: Seedling Emergence

PMRA Submission Number N/A

TABLE t VALUE (0.05 (2), 6) 2.447

TABLE t VALUE (0.01 (2), 6) = 3.707

EPA MRID Number 47748202

NO significant difference at alpha=0.05

NO significant difference at alpha=O.Ol

Title: Tribenuron methyl & sugarbeet height (em); lbs ai/A

File: 8402sh Transform: NO TRANSFORM

t-test of Surfactant and Blank Controls Ho:GRP1 MEAN = GRP2 MEAN

GRP1 (SURFACTANT CRTL) MEAN

GRP2 (BLANK CRTL) MEAN

DIFFERENCE IN MEANS

8.1250 CALCULATED t VALUE

7.9250 DEGREES OF FREEDOM =

0.2000

6

0.1818

2-sided t VALUE (0.05, 6) = 2.4469

2-sided t VALUE (0.01, 6) = 3.7074

NO significant difference at alpha=0.05

NO significant difference at alpha=O.Ol

WARNING: This procedure assumes normality and equal variances!

Page 14 of 14