Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 1 of 40 

Data Requirement: PMRA Data Code: 9.8.4 (TGAI) or 9.8.6 (EP) 

EPA DP Barcode: 427851 

OECD Data Point: IIA 8.12 (TGAI) and IIIA 10.8.1.1 (EP) 

EPA Guideline: 850.4150 

Test material: Atrazine SC Purity: 43.0% (w/w) 

Common name: 

Chemical name: IUPAC: 

CAS name: 

CAS No.: 1912-24-9 

Synonyms: A8566A; G30027 SC (479.37)

Primary Reviewer: Joan Gaidos Signature: 

Senior Scientist, CDM Smith Date: 11/6/15 

Secondary Reviewer: Teri S. Myers Signature: 

Senior Scientist, CDM Smith Date: 11/16/15

Primary Reviewer: Frank T. Farruggia, Ph.D. Date: 2/23/16 

EPA/OPP/ERB3 

Reference/Submission No.: {.....................}

Company Code {............} [For PMRA]

Active Code {............} [For PMRA] 

Use Site Category: {............} [For PMRA] 

EPA PC Code 080803

Date Evaluation Completed: 23-02-2016 

CITATION: Martin J.A. Atrazine SC (A8566A) – Vegetative Vigor Test with Extended Exposure to View Potential 

Recovery. Unpublished study performed by Smithers Viscient, Wareham, Massachusetts and sponsored by 

Syngenta crop Protection, LLC, Greensboro, North Carolina. Laboratory Study Number: 1781.7001. Study 

completed March 13, 2015. 

EXECUTIVE SUMMARY:

The effect of Atrazine on the vegetative vigor of monocot corn, Zea mays; onion, Allium cepa; ryegrass, Lolium 

perenne; and oat, Avena sativa) and dicot (cabbage, Brassica oleracea; lettuce, Lactuca sativa; carrot, Daucus 

carota; cucumber, Cucumus sativa; soybean, Glycine max; tomato, Lycopersicon esculentum) crops was studied at a 

nominal concentration of 0 (negative), 0.0050, 0.0098, 0.025, 0.050, 0.098 and 0.25 lb ai/A for cabbage, lettuce, 

soybean and tomato; 0 (negative), 0.0098, 0.025, 0.050, 0.098, 0.25 and 0.50 lb ai/A for carrot and cucumber; 0 

(negative), 0.050, 0.098, 0.25, 0.50, 0.98 and 2.5 lb ai/A for oat and onion; 0 (negative), 0.25, 0.50, 1.0, 2.5, 5.0 and 

10 lb ai/A for ryegrass; and 0 (negative), 0.50, 0.98, 2.5, 5.0, 9.8 and 25 lb ai/A for corn. Measured application rate 

were <LOQ (negative), 0.0043/0.0044, 0.0095/0.0099, 0.022/0.024, 0.044/0.047, 0.092/0.096 and 0.22 lb ai/A for 

lettuce and cabbage; <LOQ (negative), 0.0044, 0.0074, 0.021, 0.047, 0.094 and 0.24 lb ai/A for soybean and tomato; 

<LOQ (negative), 0.0095/0.0099, 0.022/0.024, 0.044/0.047, 0.092/0.096, 0.22 and 0.45/0.51 lb ai/A for carrot and 

cucumber; <LOQ (negative), 0.044/0.047, 0.092/0.094, 0.22/0.24, 0.45, 0.91/0.94 and 2.3/2.4 lb ai/A for oat and 

onion; <LOQ (negative), 0.22, 0.51, 0.97, 2.4, 4.6 and 9.6 lb ai/A for ryegrass; and <LOQ (negative), 0.45, 0.91, 

2.4, 4.5, 9.1 and 24 lb ai/A for corn. LOQ was 0.00032 lb ai/A for cabbage, ryegrass and cucumber; and 0.00035 lb 

ai/A for lettuce, carrot, onion, corn, oat, soybean and tomato. 

Digitally signed by FRANK FARRUGGIA 

DN: c=US, o=U.S. Government, 

ou=USEPA, ou=Staff, cn=FRANK 

FARRUGGIA, dnQualifier=0000048865 

Date: 2016.02.29 12:17:05 -05'00'
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 2 of 40 

The growth medium used in the vegetative vigor test was natural loam soil augmented with washed silica sand (pH 

and organic carbon not reported; 91% sand, 7% silt and 2% clay). For Test 1, on day 21 the surviving plants per pot 

were recorded, and plant height and dry weight were measured. For Test 2, on day 42 the surviving plants per pot 

were recorded, and plant height and dry weight were measured; height data was also reported for day 21 of the 42 

day study. 

Test 1, 21 days 

The negative control survival was 100%. There were significant inhibitions in all species except cabbage and corn. 

Significant inhibitions in survival for carrot, lettuce, soybean and tomato of 15 to 75% were found at the highest 

concentrations tested, application rates of 0.092 to 0.45 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). There 

were also significant inhibitions in cucumber of 8, 20, 60 and 88% at 0.047, 0.096, 0.22 and 0.51 lb ai/A; in oat of 3, 

5, 30, 70 and 100% at 0.094, 0.24, 0.45, 0.91 and 2.4 lb ai/A; in onion of 5, 33, 70 and 90% at 0.22, 0.45, 0.94 and 

2.3 lb ai/A; and in ryegrass of 25, 35 and 55% at 2.4, 4.6 and 9.6 lb ai/A (Jonckheere-Terpstra Step-Down test, 

p<0.05). 

There were significant inhibitions in dry weight in all species compared to the negative control. The dry weight 

significant inhibitions were 10 to 83% for carrot, starting at 0.0095 lb ai/A, and 38 to 91% for onion starting at 0.044 

lb ai/A (Williams test, p<0.05), and 17 to 79% for cucumber starting at 0.0099 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05) over all concentrations tested. Significant inhibitions in lettuce dry weight were also 24 to 86% 

from the 0.0095 to the 0.22 lb ai/A treatment (Williams test, p<0.05). Significant inhibitions of 10 to 91% at 0.021 

to 9.6 lb ai/A were observed in cabbage, oat, onion, ryegrass, soybean and tomato (Williams test, p<0.05). 

Inhibitions for corn dry weight were 18 and 20% at 2.4 and 24 lb ai/A (Dunnett’s test, p<0.05). 

There were significant inhibitions in height in all species compared to the negative control with the exception of 

cabbage. Significant height inhibitions in carrot were 8 to 51% from 0.024 to 0.45 lb ai/A, in cucumber were 22 to 

63% from 0.022 to 0.51 lb ai/A, and in soybean were 12 to 64% from 0.021 to 0.24 lb ai/A (Williams test, p<0.05), 

and in tomato were 11 to 41% from 0.021 to 0.24 lb ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). Significant 

inhibitions in height were also observed in corn, oat and ryegrass of 7 to 40% at 0.45 to 24 lb ai/A (Williams test, 

p<0.05). Significant inhibitions in lettuce and onion height were 13 to 57% at 0.044 to 2.3 lb ai/A (JonckheereTerpstra Step-Down test, p<0.05). 

The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with NOAEC and EC25

values of <0.044 lb ai/A and 0.0379 lb ai/A, respectively; the most sensitive dicot was cucumber based on dry 

weight with NOAEC and EC25 values of <0.0099 and 0.0145 lb ai/A, respectively. 

Based on the phytotoxicity rating system used by the study author, there were no effects in the negative control, but 

complete effects (100%, dead plant) in all species with the exception of corn, which had no effects. The effects 

were dose-dependent. 

 

Test 2, 42 days 

The negative control survival was 100%. There were significant inhibitions in survival in all species except cabbage 

and corn. Significant inhibitions in cucumber were 13, 55 and 100% at 0.096, 0.22, and 0.51 lb ai/A; in oat were 8, 

30, 63, 85 and 100% at 0.094, 0.24, 0.45, 0.91 and 2.4 lb ai/A; and in ryegrass were 28, 68 and 90% at 2.4, 4.6 and 

9.6 lb ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). Significant inhibitions in carrot, soybean and tomato 

survival were 65, 40 and 68% at the highest concentration tested (0.24 to 0.45 lb ai/A), and significant inhibitions in 

lettuce of 23 and 93% and onion of 70 and 95% were observed at the two highest concentrations tested (0.092 to 2.3 

lb ai/A) (Mann-Whitney U Two-Sample test, p<0.05). 

There were significant inhibitions in dry weight in all species, with the exception of cabbage. Significant inhibitions 

in dry weight of onion were 35 to 74% from 0.22 to 2.3 lb ai/A, and in soybean were 31 to 89% at all concentrations 

tested at 0.0044 to 0.24 lb ai/A (Williams test, p<0.05). Significant inhibitions in corn dry weight were 29 to 31% at 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 3 of 40 

2.4 to 24 lb ai/A; in oat dry weight were 75% at 0.45 lb ai/A, and in tomato dry weight were 51% at 0.24 lb ai/A 

(Dunnett’s test, p<0.05). Significant inhibitions in lettuce dry weight were 11 to 41% from 0.024 to 0.22 lb ai/A 

(Jonckheere-Terpstra Step-Down test, p<0.05). Significant inhibitions for carrot and cucumber were 7 to 33% at 

0.0095 to 0.45 lb ai/A; and for ryegrass was 83% at 9.6 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

There were significant inhibitions in seedling height in all species with the exception of cabbage and lettuce. The 

reviewer reported significant height inhibitions of 14 to 62% at all test concentrations for soybean, 0.0044 to 0.24 lb 

ai/A (Williams test, p<0.05). Significant inhibitions for corn, oat, onion, ryegrass and tomato height were 12 to 42% 

at 0.24 to 24 lb ai/A (Dunnett’s test, p<0.05). Inhibitions for carrot and cucumber were 12 to 18% at 0.022 to 0.45 lb 

ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with NOAEC and EC25

values of 0.092 lb ai/A and 0.0996 lb ai/A, respectively; the most sensitive dicot was soybean based on dry weight 

with NOAEC and EC25 values of <0.0044 and 0.00397 lb ai/A, respectively. 

Based on the phytotoxicity rating system used by the study author, there were no effects in the negative control, but 

complete effects (100%, dead plant) in all species with the exception of corn, which had no effects. The effects 

were dose-dependent. 

Test 2a, 21 days of 42 day study 

Survival in the negative control was 100%, based on study author results from the full 42 day study. Raw data and 

percent inhibitions for survival at 21 days of the 42 day study was not provided, however, the study author did report 

the results of statistical analysis (NOEC and ECx). Based on application rates greater than the NOEC, there 

appeared to be significant effects on survival at the highest nominal application rate for carrot at 0.50 lb ai/A; and 

for lettuce, soybean and tomato at 0.25 lb ai/A (Fisher’s Exact Test with Bonferroni-Holm’s Adjustment, p<0.05). 

There were also significant effects at the two highest nominal application rates for cucumber (0.25 and 0.50 lb ai/A) 

and onion (0.98 and 2.5 lb ai/A). The study author indicated there was complete morality of cucumber at the highest 

treatment concentration, 0.50 lb ai/A. Ryegrass had significant effects in survival at 2.5, 5.0 and 10 lb ai/A, and oat 

had significant effects at 0.50, 0.98 and 2.5 lb ai/A. There were no significant effects based on the study author’s

NOEC for cabbage and corn. The reviewer was unable to review or confirm these results for survival due to the 

lack of raw data for analysis. 

There were significant inhibitions in seedling height in all species with the exception of cabbage. The reviewer 

reported significant height inhibitions for onion of 12 to 59% over all test concentrations, 0.044 to 2.3 lb ai/A, and 

significant height inhibitions for soybean of 14 to 68% over all test concentrations, 0.0044 to 0.24 lb ai/A (Williams 

test, p<0.05). Lettuce, oat, and ryegrass also showed significant inhibitions in height of 8 to 63% at 0.024 to 9.6 lb 

ai/A (Williams test, p<0.05). Significant inhibitions in carrot height were 10 to 58% over all test concentrations, 

0.0095 to 0.45 lb ai/A, and in cucumber height were 18 to 40%, from 0.022 to 0.22 lb ai/A (Jonckheere-Terpstra 

Step-Down test, p<0.05). Significant inhibitions in tomato height of 11 to 64% were observed at 0.021 to 0.24 lb 

ai/A (Dunnett’s test, p<0.05), and in corn height of 8 to 15% were observed at 2.4 to 24 lb ai/A (Mann-Whitney U 

Two-Sample test, p<0.05). 

The most sensitive monocot, based on the reviewer’s results, was onion based on height with NOAEC and EC25

values of <0.044 lb ai/A and 0.146 lb ai/A, respectively; the most sensitive dicot was soybean based on height with 

NOAEC and EC25 values of <0.0044 and 0.0194 lb ai/A, respectively. 

The phytotoxicity on day 21 of the 42 day study was not reported. 

The study author also reported growth rates for height and weight, however the reviewer could not verify these rates. 

Study author results presented in the conclusions at the end of the DER. 

 

Maximum Labeled Rate: 4 lb ai/A (4500 g ai/ha). 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 4 of 40 

Test 1, 21 days 

Most sensitive monocot: Onion, based on dry weight* 

EC50/IC50: 0.126 lb ai/A 95% C.I.: 0.0952-0.167 lb ai/A 

EC25/IC25: 0.0379 lb ai/A 95% C.I.: 0.0217-0.0599 lb ai/A 

EC05/IC05: 0.00673 lb ai/A 95% C.I.: N/A-0.0219 lb ai/A 

NOEC: <0.044 lb ai/A 

Slope: N/A 95% C.I.: N/A 

 * IC25 value was slightly less than the lowest concentration tested (0.044 lb ai/A). 

Most sensitive dicot: Cucumber, based on dry weight 

EC50/IC50: 0.0764 lb ai/A 95% C.I.: 0.0498-0.117 lb ai/A 

EC25/IC25: 0.0145 lb ai/A 95% C.I.: 0.00586-0.0297 lb ai/A 

EC05/IC05: 0.00132 lb ai/A 95% C.I.: N/A-0.00836 lb ai/A 

NOEC: <0.0099 lb ai/A 

Slope: N/A 95% C.I.: N/A 

Test 2, 42 days 

Most sensitive monocot: Onion, based on dry weight 

EC50/IC50: 0.381 lb ai/A 95% C.I.: 0.266-0.546 lb ai/A 

EC25/IC25: 0.0996 lb ai/A 95% C.I.: 0.049-0.176 lb ai/A 

EC05/IC05: 0.0145 lb ai/A 95% C.I.: N/A-0.0594 lb ai/A 

NOEC: 0.092 lb ai/A 

Slope: N/A 95% C.I.: N/A 

Most sensitive dicot: Soybean, based on dry weight* 

EC50/IC50: 0.019 lb ai/A 95% C.I.: 0.015-0.0239 lb ai/A 

EC25/IC25: 0.00397 lb ai/A 95% C.I.: 0.00252-0.00594 lb ai/A 

EC05/IC05: 0.000419 lb ai/A 95% C.I.: N/A-0.00138 lb ai/A 

NOEC: <0.0044 lb ai/A 

Slope: N/A 95% C.I.: N/A 

 * IC25 value was slightly less than the lowest concentration tested (0.0044 lb ai/A). 

 

Test 2a, 21 days of 42 days 

Most sensitive monocot: Onion, based on height (only endpoint analyzed) 

EC50/IC50: 0.774 lb ai/A 95% C.I.: 0.627-0.955 lb ai/A 

EC25/IC25: 0.146 lb ai/A 95% C.I.: 0.106-0.195 lb ai/A 

EC05/IC05: 0.0133 lb ai/A 95% C.I.: 0.00011-0.0325 lb ai/A 

NOEC: <0.044 lb ai/A 

Slope: N/A 95% C.I.: N/A 

Most sensitive dicot: Soybean, based on height (only endpoint analyzed) 

EC50/IC50: 0.0882 lb ai/A 95% C.I.: 0.076-0.102 lb ai/A 

EC25/IC25: 0.0194 lb ai/A 95% C.I.: 0.0151-0.0244 lb ai/A 

EC05/IC05: 0.00219 lb ai/A 95% C.I.: 0.000499-0.00429 lb ai/A 

NOEC: <0.0044 lb ai/A 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 5 of 40 

Slope: N/A 95% C.I.: N/A 

This toxicity study is classified as supplemental for the herein labeled “Test 1”-21-day Study. The study was 

downgraded because the study authors failed to obtain NOAECs for the most sensitive endpoints for Carrot, 

Cucumber, and Onion, also the IC25 for onion dry weight (most sensitive endpoint) was below the lowest tested 

concentration. The concurrent study labeled here as Test 2 and Test 2a is classified as supplemental as well, as the 

study design did not allow for dry weight endpoints at the 21-day period, did not provide survival at 21-days, and 

the 42-day endpoints failed to determine a NOAEC for soybean dry weight (most sensitive endpoint) and the IC25

was below the lowest tested concentration. Lastly, the most sensitive endpoint for carrot, cucumber, oat and ryegrass 

in the 42-day study was survival. The study is designed to capture sub-lethal effects, therefore, survival is not 

expected to be the most sensitive endpoint 

Table 1a. Summary of most sensitive parameters by species (lb ai/A); Test 1, 21 days 

Species Endpoint NOEC EC05/IC05 EC25/IC25 EC50/IC50

Cabbage Dry weight 0.044 0.0148 0.059 0.154 

Carrot Dry weight <0.0095 0.0123 0.0544 0.153 

Corn* Dry weight 0.91 0.37 >24 >24 

Cucumber Dry weight <0.0099 0.00132 0.0145 0.0764 

Lettuce Dry weight 0.0044 0.00653 0.0215 0.0494 

Oat Dry weight 0.45 0.211 0.354 0.773 

Onion** Dry weight <0.044 0.00673 0.0379 0.126 

Ryegrass Dry weight 0.22 0.0292 0.243 1.06 

Soybean Dry weight 0.0074 0.00422 0.018 0.0491 

Tomato Dry weight 0.0074 0.00572 0.0286 0.0876 

* Not a dose response and/or ECx/ICx values are not bracketed by the test concentrations and are unreliable. 

** IC25 value was slightly less than the lowest concentration tested. 

Table 1b. Summary of most sensitive parameters by species (lb ai/A); Test 2, 42 days 

Species Endpoint NOEC EC05/IC05 EC25/IC25 EC50/IC50

Cabbage None 0.22 >0.22 >0.22 >0.22 

Carrot Survival 0.22 0.22 0.31 0.393 

Corn* Dry weight 0.91 0.0358 5.83 >24 

Cucumber Survival 0.047 0.0828 0.134 0.188 

Lettuce Dry weight 0.0095 0.00844 0.061 0.241 

Oat Survival 0.047 0.0919 0.204 0.355 

Onion Dry weight 0.092 0.0145 0.0996 0.381 

Ryegrass Survival 0.97 0.983 2.08 3.51 

Soybean** Dry weight <0.0044 0.000419 0.00397 0.019 

Tomato Dry weight 0.094 0.0411 0.119 0.249 

* Not a dose response and/or ECx/ICx values are not bracketed by the test concentrations and are unreliable. 

** IC25 value was slightly less than the lowest concentration tested. 

Table 1c. Summary of most sensitive parameters by species (lb ai/A); Test 2a, 21 days of 42 days (height only 

endpoint analyzed) 

Species Endpoint NOEC EC05/IC05 EC25/IC25 EC50/IC50

Cabbage None 0.22 >0.22 >0.22 >0.22 

Carrot Height <0.0095 0.0285 0.135 0.398 

Corn* Height 0.91 1.22 >24 >24 

Cucumber Height 0.0099 0.00341 0.0509 0.333 

Lettuce Height 0.0095 0.019 0.0601 0.134 

Oat Height 0.094 0.0232 0.201 0.898 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 6 of 40 

Onion Height <0.044 0.0133 0.146 0.774 

Ryegrass Height 0.97 0.848 2.78 6.35 

Soybean Height <0.0044 0.00219 0.0194 0.0882 

Tomato Height 0.0074 0.0873 0.145 0.206 

* Not a dose response and/or ECx/ICx values are not bracketed by the test concentrations and are unreliable. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 7 of 40 

I. MATERIALS AND METHODS

GUIDELINE FOLLOWED: This study was conducted in compliance with OPPTS 850.4150: 

Vegetative Vigor (January 2012) and OECD Guideline No. 227: 

Terrestrial Plant Test: Vegetative Vigor test. The reviewer evaluated 

the study methods according to EPA Ecological Effects Test 

Guidelines, OCSPP Guideline 850.4150: Vegetative Vigor. There were 

some deficiency and deviations noted by the reviewer. 

1. The physico-chemical properties of the test material were not reported. 

2. Survival at 21 days in the 42 day study was analyzed by the study author, however raw 

data were not provided. Therefore, the reviewer could not verify the statistical analysis 

or results. 

3. The IC25 value was slightly less than the lowest concentration tested for the most 

sensitive monocot for Test 1, onion, and the most sensitive dicot for Test 2, soybean. 

EPA recommends that test concentrations bracket the most sensitive NOEC and IC25

values. 

4. In the Test 2, the 42 day study, the most sensitive endpoint for carrot, cucumber, oat and 

ryegrass was survival. The study is designed to capture sub-lethal effects, therefore, 

survival is not expected to be the most sensitive endpoint. 

 The deficiency and deviations did have an impact on the acceptability of this study. 

COMPLIANCE: Signed and dated GLP, Quality Assurance and No Data Confidentiality 

statements were provided. This study was conducted in compliance with 

USEPA (40 CFR, Part 160) and OECD (OECD, 1998) Principles of Good 

Laboratory Practice., with the following exception: routine water and food 

contaminant screening analyses for PCBs, pesticides and toxic metals were 

conducted using standard U.S. EPA procedures by GeoLabs, Inc, Braintree, 

Massachusetts and are considered facility records under Smithers Viscient’s 

Standard Operating Procedures. Since the analyses were conducted 

following standard validated methods, these exceptions had no impact on 

the study results. 

A. MATERIALS:

 1. Test Material Atrazine SC

Description: White liquid.

Lot No./Batch No.: 726537 

Purity: 43.0% (w/w) 

Stability of compound 

under test conditions: Analytical determinations based on measured concentration of the test 

material in the spray solution yielded a recoveries of 83.7-102.2% of 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 8 of 40 

nominal. Stability was not determined. QC recoveries ranged from 90.5-

104.5%. Method recoveries of the atrazine from 1% crop oil in deionized 

water were 104±7.97% (n=9). 

 (OECD recommends chemical stability in water and light) 

Storage conditions of 

test chemicals: The test material was stored in the dark at room temperature. 

 Table 2. Physical/chemical properties of Atrazine 

Parameter Values Comments

Water solubility at 20 ̊C Not reported

Vapor pressure Not reported

UV absorption Not reported

pKa Not reported

Kow Not reported

 2. Test organism: 

Monocotyledonous species: Corn (Zea mays, Golden Bantam); Onion (Allium cepa, Yellow Granex); 

Ryegrass (Lolium perenne, Linn) and Oat (Avena sativa, Swan); EPA recommends four monocots in two 

families, including corn. 

Dicotyledonous species: Lettuce (Lactuca sativa, Prizehead); Cabbage, Brassica oleracea, Ganzales); 

Carrot (Daucus carota, Imperator 58); Cucumber (Cucumus sativa, Bush Champion); Tomato 

(Lycopersicon esculentum, Celebrity Hybrid); and Soybean (Glycine max, Envy); EPA recommends six 

dicots in four families, including soybean and a root crop. 

OECD recommends a minimum of three species selected for testing, at least one from each of the 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: Cabbage, onion from Park Seed Company; carrot and lettuce from Sustainable Seed 

Company; corn, cucumber from Burpee; oat from L.A. Hearne Compound; ryegrass from Granite Seed, 

soybean from Johnny’s Selected Seeds; and tomato from Tomato Growers Supply Company. 

Prior seed treatment/sterilization: The seeds were not treated with any type of fungicides, insecticides, or 

any pesticides. 

Historical % germination of seed: Carrot, 83%; lettuce, 85%; oat, 90%; ryegrass, 95%; soybean, 87%; 

cabbage, corn, cucumber, onion and tomato, N/A. 

 Seed storage, if any: Seeds stored refrigerated in the dark until use. 

B. STUDY DESIGN:

1. Experimental Conditions 

a. Limit test: None. 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 9 of 40 

b. Range-finding study: A preliminary 21-day range-finding study was conducted exposing cabbage, 

cucumber, lettuce, soybean and tomato to nominal concentrations of 0.000050, 0.00050, 0.0050, 0.050, 

0.50 and 5.0 lb ai/A. 

c. Definitive Study 

Table 3: Experimental Parameters – Vegetative Vigor.

Parameters Vegetative Vigor 

Details Remarks 

Criteria 

Duration of the test Test 1: 21 days 

Test 2: 42 days Recommended test duration is 14-21 days. 

OECD recommends that the test be terminated no 

sooner than 14 days after 50 percent of the control 

seedlings have emerged

Number of 

seeds/plants/species/ 

replicate

Oat, onion and ryegrass, 5 

replicates with 8 plants per 

replicate; 

All others 10 replicates with 4 

plants per replicates. 

Five plants per replicate are recommended

Number of plants retained 

after thinning

At the 2-4 leaf stage. 

Number of replicates 

Control:

Adjuvant control:

Treated:

Control:

Adjuvant control:

Treated:

Oat, onion and ryegrass: 

5 

N/A

5 

All others:

10

N/A

10

Four replicates per dose should be used. 

OECD recommends a minimum of four replicates 

per treatment
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 10 of 40 

Parameters Vegetative Vigor 

Details Remarks 

Criteria 

Test concentrations (lb 

ai/A)

Nominal:

Measured: 

0 (negative), 0.0050, 0.0098, 

0.025, 0.050, 0.098 and 0.25 lb 

ai/A for cabbage, lettuce, soybean 

and tomato; 

0 (negative), 0.0098, 0.025, 0.050, 

0.098, 0.25 and 0.50 lb ai/A for 

carrot and cucumber; 

0 (negative), 0.050, 0.098, 0.25, 

0.50, 0.98 and 2.5 lb ai/A for oat 

and onion; 

0 (negative), 0.25, 0.50, 1.0, 2.5, 

5.0 and 10 lb ai/A for ryegrass; 

and 0 (negative), 0.50, 0.98, 2.5, 

5.0, 9.8 and 25 lb ai/A for corn. 

<LOQ (negative), 0.0043/0.0044, 

0.0095/0.0099, 0.022/0.024, 

0.044/0.047, 0.092/0.096 and 0.22 

lb ai/A for cabbage and lettuce; 

<LOQ (negative), 0.0044, 0.0074, 

0.021, 0.047, 0.094 and 0.24 lb 

ai/A for soybean and tomato; 

<LOQ (negative), 0.0095/0.0099, 

0.022/0.024, 0.044/0.047, 

0.092/0.096, 0.22 and 0.45/0.51 lb 

ai/A for carrot and cucumber; 

<LOQ (negative), 0.044/0.047, 

0.092/0.094, 0.22/0.24, 0.45, 

0.91/0.94 and 2.3/2.4 lb ai/A for 

oat and onion; 

<LOQ (negative), 0.22, 0.51, 

0.97, 2.4, 4.6 and 9.6 lb ai/A for 

ryegrass; 

and <LOQ (negative), 0.45, 0.91, 

2.4, 4.5, 9.1 and 24 lb ai/A for 

corn. 

LOQ = 0.00032 lb ai/A for cabbage, ryegrass 

and cucumber;

LOQ = 0.00035 lb ai/A for lettuce, carrot, 

onion, corn, oat, soybean and tomato. 

Five test concentrations should be used with a dose 

range of 2X or 3X progression

OECD 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.

Method and interval of 

analytical verification

Samples were taken from the 

negative control and the treatment 

groups for analysis via HPLC 

with UV detection: Aglient 

Zorbax SB-C18 column and 224 

nm wavelength
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 11 of 40 

Parameters Vegetative Vigor 

Details Remarks 

Criteria 

LOQ: 

LOD:

0.00032 and 0.00035 lb ai/A 

N/A

Adjuvant (type, percentage, 

if used)

Crop oil (AGri-Dex), 1% 

Test container (pot) 

Size/Volume

Material: 

(glass/polystyrene)

13 cm tall and 26 cm top diameter 

(20 cm bottom diameter); 20 cm 

fill paper interior base. 

Polypropylene 

Non-porous containers should be used. 

OECD recommends that non-porous plastic or 

glazed pot be used.

Growth facility Greenhouse 

Method/depth of seeding Seeds were planted and allowed to 

emerge and the appropriate 

number of seedlings selected at 

the 2-4 leaf stage. 

Test material application 

Application time including 

the plant growth stage

Number of application 

Application interval

Method of application

Application was made at the 2-4 

leaf stage. 

1 

N/A- single application 

The test material was applied 

using a conventional agricultural 

overhead atomizing spray nozzle 

(8001-E-SS) and revolving belt. 

Details of soil used

Geographic location

Depth of soil collection 

Soil texture

% sand 

N/A

N/A

Sand

91

Natural loam soil combined with washed silica 

sand. 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 12 of 40 

Parameters Vegetative Vigor 

Details Remarks 

Criteria 

% silt 

% clay 

pH:

% organic carbon 

CEC (meq/100 g) 

Moisture at 1/3 atm (%) 

7 

2 

Not reported

Not reported

Not reported

Not reported

Not reported

Soil mixes containing sandy loam, loam, or clay 

loam soil with no greater than 2% organic matter 

are preferable. Glass beads, rock wool, and 100% 

acid washed sand are not preferred.

OECD prefers the soil to be sieved (0.5 cm) to 

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 recommended pH is between 5.0 and 7.5.

Details of nutrient medium, 

if used

Peters 20-20-20 (N-P-K), 400 

mg/L. Applied by sub-irrigation 

twice weekly.

Watering regime and 

schedules

Water source/type:

Volume applied:

Interval of application:

Method of application:

Well water (Town of Wareham). 

Not reported.

Daily. 

The plants were bottom watered 

after being initially top watered 

(100 mL deionized water) to 

promote capillary action. 

EPA prefers that bottom watering be utilized for 

seedling emergence studies so that the chemical is 

not leached out of the soil during the test.

Any pest control 

method/fertilization, if used 

None reported 

Test conditions

Temperature:

Photoperiod:

Light intensity and quality: 

Relative humidity:

15-51 ̊C

16L:8D

Natural sunlight supplemented 

with artificial light.

59-1300 μmol/m2/sec 

15-98% 

EPA prefers that the cold vs warm loving plants be 

tested in two separate groups to optimize plant 

growth.

OECD prefers that the temperature, humidity and 

light conditions be suitable for maintaining normal 

growth of each species for the test period.

Reference chemical (if 

used)

Name:

Concentrations: 

N/A

Other parameters, if any None 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 13 of 40 

 

2. Observations: 

Table 4: Observation Parameters - Vegetative Vigor.

Parameters Vegetative Vigor 

Details Remarks 

Parameters measured (e.g., number 

of germinated seeds, emerged 

seedlings, plant height, dry weight 

or other endpoints)

- Survival 

- Height

- Mean dry weight 

- Phytotoxicity

Measurement technique for each 

parameter 

Phytotoxicity was visually 

determined. Height was 

measured to the nearest 

0.5 centimeter from the 

soil surface to the tallest 

new growth. Mean plant 

weight was estimated by 

measuring the dry weight 

following drying at 70 ± 5 

 ̊C. 

Observation intervals Each pot was inspected 

weekly and phytotoxicity 

assessments performed. 

Plant height and dry 

weight were recorded at 

study termination. 

Other observations, if any N/A 

Were raw data included? Yes 

Phytotoxicity rating system, if used The health rating, 

including morphological 

abnormalities ranges from 

0 to 100, where 0 

indicates no injury or 

abnormality and 100 

indicates complete effect 

(dead plant). 

II. RESULTS and DISCUSSION:

A. INHIBITORY EFFECTS:

1. Vegetative Vigor: 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 14 of 40 

Test 1, 21 days 

Based on the study author results, negative control survival was 100%. There were significant inhibitions 

in all species except cabbage and corn. Study author survival inhibitions ranged from 25 to 90% at 

application rates of 0.25 to 10 lb ai/A; there was also 100% inhibition in oat at 2.5 lb ai/A compared to the 

negative control (Fisher’s Exact Test with Bonferroni-Holm’s Adjustment, p<0.05). The reviewer reported 

similar results, with survival inhibitions of carrot, lettuce, soybean and tomato of 15 to 75% at application 

rates of 0.092 to 0.45 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). There were also inhibitions in 

cucumber of 8 to 88% at 0.047 to 0.51 lb ai/A; in oat inhibitions of 3, 5, 30, 70 and 100% at 0.094, 0.24, 

0.45, 0.91 and 2.4 lb ai/A; in onion of 5, 33, 70 and 90% at 0.22, 0.45, 0.94 and 2.3 lb ai/A; and ryegrass of 

25, 35 and 55% at 2.4, 4.6 and 9.6 lb ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). 

The study author found significant inhibitions in dry weight in all species. Study author dry weight 

significant inhibitions ranged from 15 to 90% at 0.0098 to 25 lb ai/A compared to the negative control 

(Dunnett’s Multiple Comparison test, p<0.05); with exception of cucumber, which had inhibitions of 17 to 

79% at all test concentrations (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05). The 

reviewer reported similar results, with dry weight inhibitions of 10 to 91% at 0.0095 to 9.6 lb ai/A for 

cabbage, carrot, lettuce, oat, onion, ryegrass, soybean and tomato (Williams test, p<0.05). Inhibitions for 

corn dry weight were 18 and 20% at 2.4 and 24 lb ai/A (Dunnett’s test, p<0.05). Inhibitions for cucumber 

dry weight were 17 to 79% at all test concentrations (Jonckheere-Terpstra Step-Down test, p<0.05). 

The study author found significant inhibitions in height in all species with the exception of cabbage. Study 

author height significant inhibitions ranged from 9 to 64% at 0.025 to 25 lb ai/A compared to the negative 

control (Dunnett’s Multiple Comparison test, p<0.05); with exception of lettuce and tomato, which had 

inhibitions of 14 to 56% at 0.050 to 0.25 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, 

p<0.05). The reviewer reported similar results, with height inhibitions of 7 to 64% at 0.021 to 24 lb ai/A 

for carrot, corn, cucumber, oat, ryegrass, and soybean (Williams test, p<0.05). Inhibitions for lettuce, 

onion and tomato height were 8 to 57% at 0.021 to 2.3 lb ai/A (Jonckheere-Terpstra Step-Down test, 

p<0.05). 

The most sensitive monocot, based on the study author's results, was onion based on dry weight with 

NOAEC and EC25 values of <0.050/0.00066 lb ai/A (<NOEC/EC05) and 0.013 lb ai/A, respectively; the 

most sensitive dicot was cucumber based on dry weight with NOAEC and EC25 values of <0.0098/0.0010 

(<NOEC/EC05) and 0.014 lb ai/A, respectively. 

The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with NOAEC 

and EC25 values of <0.044 lb ai/A and 0.0379 lb ai/A, respectively; the most sensitive dicot was cucumber 

based on dry weight with NOAEC and EC25 values of <0.0099 and 0.0145 lb ai/A, respectively. 

Based on the phytotoxicity rating system used by the study author, there were no effects in the negative 

control, but complete effects (100%, dead plant) in all species with the exception of corn, which had no 

effects. The effects were dose-dependent. 

 

Test 2, 42 days 

Based on the study author results, negative control survival was 100%. There were significant inhibitions 

in all species except cabbage and corn. Study author survival inhibitions ranged from 23 to 95% at 

application rates of 0.25 to 10 lb ai/A; there was also 100% inhibition in oat at 2.5 lb ai/A compared to the 

negative control (Fisher’s Exact Test with Bonferroni-Holm’s Adjustment, p<0.05). The reviewer reported 

similar results, with survival inhibitions of carrot, lettuce, onion, soybean and tomato of 23 to 95% at 

application rates of 0.092 to 2.3 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). There were also 

inhibitions in cucumber of 13, 55 and 100% at 0.096, 0.22, and 0.51 lb ai/A; in oat inhibitions of 8, 30, 63, 

85 and 100% at 0.094, 0.24, 0.45, 0.91 and 2.4 lb ai/A; and ryegrass of 28, 68 and 90% at 2.4, 4.6 and 9.6 

lb ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 15 of 40 

The study author found significant inhibitions in dry weight in all species, with the exception of cabbage. 

Study author dry weight inhibitions ranged from 7 to 89% at 0.0098 to 25 lb ai/A compared to the negative 

control (Dunnett’s Multiple Comparison test, p<0.05); with exception of cucumber, which had inhibitions 

of 9 to 29% at 0.0098 to 0.25 lb ai/A; and lettuce, which had inhibitions of 36% at 0.098 lb ai/A 

(Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05). The reviewer reported similar results, with 

dry weight significant inhibitions of 31 to 89% at 0.0044 to 2.3 lb ai/A for onion and soybean (Williams 

test, p<0.05). Significant inhibitions for corn dry weight were 29 to 31% at 2.4 to 24 lb ai/A, significant 

inhibitions for oat were 75% at 0.45 lb ai/A, and significant inhibitions in tomato dry weight were 51% at 

0.24 lb ai/A (Dunnett’s test, p<0.05). Inhibitions for lettuce dry weights were 11 to 41% at 0.024 to 0.22 lb 

ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). Inhibitions for carrot and cucumber were 7 to 33% at 

0.0095 to 0.45 lb ai/A; and for ryegrass was 83% at 9.6 lb ai/A (Mann-Whitney U Two-Sample test, 

p<0.05). 

The study author found significant inhibitions in height in all species with the exception of cabbage and 

lettuce. Study author height inhibitions ranged from 18 to 62% at 0.0044 to 10 lb ai/A compared to the 

negative control for oat, onion, ryegrass, soybean and tomato (Dunnett’s Multiple Comparison test, 

p<0.05). Inhibitions for carrot, corn, and cucumber ranged from 12 to 18% at 0.025 to 25 lb ai/A 

(Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05). The reviewer reported similar results, 

with height inhibitions of 14 to 62% at all test concentrations for soybean (Williams test, p<0.05). 

Inhibitions for corn, oat, onion, ryegrass and tomato height were 12 to 42% at 0.24 to 24 lb ai/A (Dunnett’s 

test, p<0.05). Inhibitions for carrot and cucumber were 12 to 18% at 0.022 to 0.45 lb ai/A (Mann-Whitney 

U Two-Sample test, p<0.05). 

The most sensitive monocot, based on the study author's results, was onion based on dry weight with 

NOAEC and EC25 values of 0.050 lb ai/A (NOEC) and 0.062 lb ai/A, respectively; the most sensitive dicot 

was soybean based on dry weight with NOAEC and EC25 values of <0.0050/0.00032 (<NOEC/EC05) and 

0.0032 lb ai/A, respectively. 

The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with NOAEC 

and EC25 values of 0.092 lb ai/A and 0.0996 lb ai/A, respectively; the most sensitive dicot was soybean 

based on dry weight with NOAEC and EC25 values of <0.0044 and 0.00397 lb ai/A, respectively. 

Based on the phytotoxicity rating system used by the study author, there were no effects in the negative 

control, but complete effects (100%, dead plant) in all species with the exception of corn, which had no 

effects. The effects were dose-dependent. 

Test 2a, 21 days of 42 day study 

Survival in the negative control was 100%, based on study author results from the full 42 day study. Raw 

data and percent inhibitions for survival at 21 days of the 42 day study was not provided, however, the 

study author did report the results of statistical analysis (NOEC and ECx). Based on application rates 

greater than the NOEC, there appeared to be significant effects on survival at the highest application rate 

for carrot at 0.50 lb ai/A; and for lettuce, soybean and tomato at 0.25 lb ai/A (Fisher’s Exact Test with 

Bonferroni-Holm’s Adjustment, p<0.05). There were also effects at the two highest application rates for 

cucumber (0.25 and 0.50 lb ai/A) and onion (0.98 and 2.5 lb ai/A). Ryegrass had effects at 2.5, 5.0 and 10 

lb ai/A and oat at 0.50, 0.98 and 2.5 lb ai/A. There were no effects based on the NOEC for cabbage and 

corn. The reviewer was unable to review or confirm these results for survival due to the lack of raw data 

for analysis. 

The study author found significant inhibitions in height in all species with the exception of cabbage. Study 

author height significant inhibitions ranged from 8 to 68% at 0.0044 to 25 lb ai/A compared to the negative 

control (Dunnett’s Multiple Comparison test, p<0.05). The reviewer reported similar results, with height 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 16 of 40 

significant inhibitions for lettuce, oat, onion, ryegrass, and soybean of 8 to 68% at 0.0044 to 9.6 lb ai/A 

(Williams test, p<0.05). Significant inhibitions for tomato height were 11 to 64% at 0.021 to 0.24 lb ai/A 

(Dunnett’s test, p<0.05). Significant inhibitions for corn were 8 to 15% at 2.4 to 24 lb ai/A (Mann-Whitney 

U Two-Sample test, p<0.05). Significant inhibitions in carrot and cucumber height were 10 to 58% at 

0.0095 to 0.45 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

The most sensitive monocot, based on the study author's results, was oat based on height with NOAEC and 

EC25 values of 0.098 lb ai/A and 0.178 lb ai/A, respectively; the most sensitive dicot was soybean based on 

height with NOAEC and EC25 values of <0.00050/0.00088 (<NOEC/EC05) and 0.027 lb ai/A, respectively. 

The most sensitive monocot, based on the reviewer’s results, was onion based on height with NOAEC and 

EC25 values of <0.044 lb ai/A and 0.146 lb ai/A, respectively; the most sensitive dicot was soybean based 

on height with NOAEC and EC25 values of <0.0044 and 0.0194 lb ai/A, respectively. 

The phytotoxicity on day 21 of the 42 day study was not reported. 

B. REPORTED STATISTICS: 

Survival, dry weight, and height means and standard deviations were determined for control and treatment 

groups. For Test 1, the average specific growth rate was calculated for shoot length between test initiation and 

day 21 and shoot dry weight between test initiation and day 21 (test termination). For Test 2, the average 

specific growth rate for shoot length was calculated from test initiation to day 21, day 21 to day 42, test 

termination. The average specific growth rate for shoot dry weight was calculated using the Test 1 shoot dry 

weight data from day 21 and Test 2 shoot dry weight at test termination. 

The No-Observed-Effect Concentration (NOEC), the highest test concentration which demonstrated no 

statistically adverse effect (p < 0.05) on day 21 (Test 1) and day 42 (Test 2) percent survival, shoot length, shoot 

dry weight and average growth rate based on shoot length and shoot dry weight when compared to the control 

data was determined. Fisher's Exact Test was used to establish treatment effects for percent survival data. The 

data were first checked for normality and homogeneity of variance using Shapiro-Wilk's and Bartlett's Test. If 

the data sets passed the tests for homogeneity and normality, then the appropriate parametric procedure (i.e. 

Dunnett's Multiple Comparison Test) was used to determine the NOEC. If the data did not pass the tests for 

homogeneity and normality, then a non-parametric procedure (i.e., Wilcoxon's Test with Bonferroni-Holm's 

Adjustment) was used to determine the NOEC. All statistical determinations were made at the 95% level of 

certainty, except in the case of Shapiro-Wilks' Test and Bartlett's Test, where the 99% level of certainty was 

applied. At termination of the tests, the treatment data (percent survival, shoot length, shoot dry weight and 

average growth rate for shoot length and dry weight) were expressed as percent inhibition relative to the control. 

The ECx values and 95% confidence limits were determined by linear interpolation of response as compared 

with the control vs. nominal application rate. The regressions were limited to the concentration range for which 

a clear exposure-response relationship was observed. If less than the designated percent inhibition was observed 

for a biological endpoint, the EC values were empirically estimated to be greater than the highest application 

rate tested. 

Nominal concentrations were used. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 17 of 40 

Table 5: Effect of Atrazine on 21-Day Vegetative Vigor (Test 1)

Species Results summary for biomass (lbs ai/A) 

weight (g) NOEC* IC10 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage1 0.777-2.08 0.050 0.021 0.0087-

0.049 

0.062 0.044-

0.080 

0.161 0.107-

0.223 

N/A N/A 

Carrot2 0.0752-0.438 0.010 0.010 0.0033-

0.026 

0.034 0.022-

0.050 

0.214 0.161-

0.268 

N/A N/A 

Corn3 2.84-3.55 9.8 1.1 0.116-ND >25 N/A >25 N/A N/A N/A 

Cucumber4 0.796-3.83 <0.0098/0.0

010** 

0.0029 0.0019-

0.0072 

0.014 0.012-

0.017 

0.116 0.041-

0.161 

N/A N/A 

Lettuce5 0.111-1.07 0.0050 0.0062 0.0019-

0.012 

0.017 0.010-

0.029 

0.058 0.046-

0.066 

N/A N/A 

Oat6 0.0798-0.668 0.98 0.062 0.054-

0.143 

0.085 0.061-

0.232 

0.25 0.018-

0.473 

N/A N/A 

Onion7 0.0043-0.0473 <0.050/0.00

066** 

0.0018 0.0012-

0.0035 

0.013 0.0059-

0.043 

0.169 0.125-

0.223 

N/A N/A 

Ryegrass8 0.0479-0.273 0.25 0.259 0.0087-

0.330 

0.348 0.277-

0.58 

1.07 0.312-

4.014 

N/A N/A 

Soybean9 0.372-2.56 0.010 0.0036 0.0012-

0.013 

0.017 0.0089-

0.029 

0.059 0.042-

0.071 

N/A N/A 

Tomato10 0.602-2.08 0.010 0.013 0.0087-

0.018 

0.025 0.020-

0.057 

0.083 0.071-

0.107 

N/A N/A 

ND- Not determined. NC- Not calculable. 

*NOEC and all significant inhibitions determined by Dunnett’s Multiple Comparison Test (p<0.05), unless specified otherwise. 

**Since NOEC is lower than <lowest application rate, the EC05 is provided (NOEC/EC05). 

1 Inhibition in cabbage weight of 33 and 55% at the 0.098 and 0.25 lb ai/A. 

2 Inhibition in carrot weight of 18 to 83% at all test concentrations of 0.024 and above. 

3 Inhibition in corn weight of 18 and 20% at 2.5 and 25 lb ai/A. 

4 Inhibition in cucumber weight of 17 to 79% at all test concentrations (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05).

5 Inhibition in lettuce weight of 15 to 90% at 0.0098 to 0.25 lb ai/A. 

6 Inhibition in oat weight of 74% at 0.98 lb ai/A (not significant); 100% mortality at highest concentrations (2.5 lb ai/A). 

7 Inhibition in onion weight of 35 to 88% at all test concentrations; 2.5 lb ai/A excluded due to only one plant survived. 

8 Inhibition in ryegrass weight of 42 to 83% at 0.50 to 10 lb ai/A. 

9 Inhibition in soybean weight of 34, 42, 73 and 86% at 0.025, 0.050, 0.098 and 0.25 lb ai/A. 

10 Inhibition in tomato weight of 24, 22, 57 and 70% at 0.025, 0.050, 0.098 and 0.25 lb ai/A. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 18 of 40 

Table 5a: Effect of Atrazine on 21-Day Vegetative Vigor (Test 1)

Species Results summary for height (lbs ai/A) 

height 

(cm)

NOEC* IC10 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 21-21.8 0.25 >0.25 N/A >0.025 N/A >0.25 N/A N/A N/A 

Carrot1 11.9-24.3 0.025 0.029 0.016-

0.044 

0.259 0.161-

0.285 

0.482 0.410-ND N/A N/A 

Corn2 104-117 9.8 20.5 1.9-ND >25 N/A >25 N/A N/A N/A 

Cucumber3 17.8-48.6 0.010 0.015 0.0089-

0.017 

0.033 0.022-

0.107 

0.241 0.161-

0.375 

N/A N/A 

Lettuce4 11.5-26.5 0.025 0.034 0.020-

0.044 

0.071 0.063-

0.082 

0.196 0.152-ND N/A N/A 

Oat5 27.3-60.7 0.50 0.143 0.040-

0.339 

0.312 0.134-

0.419 

>0.98 N/A N/A N/A 

Onion6 11.2-25.8 0.098 0.013 0.0028-

0.065 

0.205 0.125-

0.285 

0.740 0.294-ND N/A N/A 

Ryegrass7 21.1-36.4 0.98 0.571 0.294-1.07 2.052 1.160-7.85 >9.812 N/A N/A N/A 

Soybean8 40.8-113 0.010 0.019 0.0028-

0.032 

0.045 0.035-

0.059 

0.116 0.098-

0.152 

N/A N/A 

Tomato9 40.2-68.3 0.050 0.052 0.011-

0.067 

0.107 0.069-

0.152 

>0.25 N/A N/A N/A 

ND- Not determined. NC- Not calculable. 

*NOEC and all significant inhibitions determined by Dunnett’s Multiple Comparison Test (p<0.05), unless specified otherwise. 

1 Inhibition in carrot height of 18 to 51% at 0.044 to 0.45 lb ai/A. 

2 Inhibition in corn height of 9% at 25 lb ai/A. 

3 Inhibition in cucumber height of 22 to 63% at 0.025 to 0.50 lb ai/A. 

4 Inhibition in lettuce height of 14, 34 and 56% at 0.050, 0.098 and 0.25 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05). 

5 Inhibition in oat height of 35% at 0.98 lb ai/A; 100% mortality at highest concentrations (2.5 lb ai/A). 

6 Inhibition in onion height of 28, 47 and 57% at 0.25, 0.50 and 0.98 lb ai/A; 2.5 lb ai/A excluded due to only plant survived.

7 Inhibition in ryegrass height of 28, 25 and 40% at 2.5, 5.0 and 10 lb ai/A. 

8 Inhibition in soybean height of 12, 28, 47 and 64% at 0.025, 0.050, 0.098 and 0.25 lb ai/A. 

9 Inhibition in tomato height of 24 and 41% at 0.098 and 0.25 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05).

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 19 of 40 

Table 5b: Effect of Atrazine on 21-Day Vegetative Vigor (Test 1)

Species Results summary for survival (lbs ai/A) 

% NOEC* EC10 95%CI EC25 95%CI EC50 95%CI slope 95%CI 

Cabbage 100 0.25 >0.25 N/A >0.025 N/A >0.25 N/A N/A N/A 

Carrot1 53-100 0.25 0.268 0.25-0.294 0.348 0.312-

0.419 

>0.50 N/A N/A N/A 

Corn 100 25 >25 N/A >25 N/A >25 N/A N/A N/A 

Cucumber2 13-100 0.050 0.057 0.038-

0.107 

0.107 0.078-

0.152 

0.196 0.143-

0.294 

N/A N/A 

Lettuce3 25-100 0.098 0.078 0.068-

0.098 

0.116 0.107-

0.125 

0.169 0.152-

0.196 

N/A N/A 

Oat4 0-100 0.25 0.285 0.232-

0.357 

0.437 0.294-

0.607 

0.696 0.455-

1.160 

N/A N/A 

Onion5 10-100 0.25 0.285 0.134-

0.392 

0.41 0.294-

0.624 

0.687 0.482-

0.981 

N/A N/A 

Ryegrass6 45-100 0.98 1.338 1.07-1.962 2.498 1.606-

7.760 

8.296 1.962-ND N/A N/A 

Soybean7 75-100 0.098 0.125 0.086-

0.187 

0.25 0.178-ND >0.25 N/A N/A N/A 

Tomato8 45-100 0.098 0.098 0.062-

0.116 

0.134 0.087-

0.169 

0.223 0.178-ND N/A N/A 

ND- Not determined. NC- Not calculable. 

*NOEC and all significant inhibitions determined by Fisher’s Exact Test with Bonferroni-Holm’s Adjustment (p<0.05). 

1 Inhibition in carrot survival of 48% at 0.45 lb ai/A. 

2 Inhibition in cucumber survival of 20, 60 and 88% at 0.098, 0.25 and 0.50 lb ai/A. 

3 Inhibition in lettuce survival of 75% at 0.25 lb ai/A. 

4 Inhibition in oat survival of 30, 70 and 100% at 0.50, 0.98 and 2.5 lb ai/A. 

5 Inhibition in onion survival of 33, 70 and 90% at 0.50, 0.98 and 2.5 lb ai/A. 

6 Inhibition in ryegrass survival of 25, 35 and 55% at 2.5, 5.0 and 10 lb ai/A. 

7 Inhibition in soybean survival of 25% at 0.25 lb ai/A. 

8 Inhibition in tomato survival of 55% at 0.25 lb ai/A. 

Plant Injury Index*; Test 1

Control Cabbage Carrot Corn Cucumber Lettuce Oat Onion Ryegrass Soybean Tomato Formulation 

Blank

0 0-10 0-100 0 0-100 0-100 0-100 0-100 0-100 0-100 0-100 N/A 

* The health rating, including morphological abnormalities ranges from 0 to 100, where 0 indicates no injury or abnormality and 100 indicates 

complete effect (dead plant). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 20 of 40 

Table 6: Effect of Atrazine on 42-Day Vegetative Vigor (Test 2)

Species Results summary for biomass (lbs ai/A) 

weight (g) NOEC* IC10 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 2.85-3.51 0.25 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Carrot1 1.44-2.02 <0.50 0.187 0.0056-ND 0.428 0.241-ND >0.50 N/A N/A N/A 

Corn2 7.34-10.6 1.0 0.8 0.032-1.9 5.4 1.2-ND >25 N/A N/A N/A 

Cucumber3 4.61-6.82 <0.0014 0.0050 0.0021-

0.017 

>0.25 N/A >0.25 N/A N/A N/A 

Lettuce4 2.91-4.92 0.25 0.022 0.0070-

0.053 

0.067 0.043-ND >0.25 N/A N/A N/A 

Oat5 0.227-1.23 0.25 0.060 0.054-

0.086 

0.072 0.062-

0.152 

0.178 0.042-

0.428 

N/A N/A 

Onion6 0.117-0.455 0.050 0.021 0.0087-

0.049 

0.062 0.044-

0.080 

0.161 0.107-

0.223 

N/A N/A 

Ryegrass7 0.152-1.18 9.8 5.44 0.0087-

5.53 

6.155 0.169-

6.601 

7.493 5.441-

8.563 

N/A N/A 

Soybean8 0.578-5.25 <0.0050/ 

0.00032** 

0.00076 0.00055-

0.0012 

0.0032 0.0021-

0.0054 

0.029 0.017-

0.035 

N/A N/A 

Tomato9 2.94-6.35 0.098 0.017 0.0078-

0.098 

0.116 0.064-ND 0.232 0.152-ND N/A N/A 

ND- Not determined. NC- Not calculable. 

*NOEC and all significant inhibitions determined by Dunnett’s Multiple Comparison Test (p<0.05), unless specified otherwise 

**Since NOEC is lower than <lowest application rate, the EC05 is provided (NOEC/EC05). 

1 Inhibition in carrot weight of 10, 9, 7 and 29% at 0.0098, 0.050, 0.098 and 0.50 lb ai/A. 

2 Inhibition in corn weight of 29, 29 and 31% at 2.5, 9.8 and 25 lb ai/A. 

3 Inhibition in cucumber weight of 13, 26, 29, 33 and 9% at 0.0098, 0.025, 0.050, 0.098 and 0.25 lb ai/A (Wilcoxon’s Test with BonferroniHolm’s Adjustment, p<0.05); 100% mortality at the highest concentration (0.50 lb ai/A). 

4 Inhibition in lettuce weight of 36% at 0.098 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05).

5 Inhibition in oat weight of 75% at 0.50 lb ai/A; 100% mortality at the highest concentrations (2.5 lb ai/A). 

6 Inhibition in onion weight of 35, 57, 74 and 70% at 0.25, 0.50, 0.98 and 2.5 lb ai/A. 

7 Inhibition in ryegrass weight of 83% at 10 lb ai/A; not significant. 

8 Inhibition in soybean weight of 31 to 89% at all test concentrations. 

9 Inhibition in tomato weight of 51% at 0.25 lb ai/A. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 21 of 40 

Table 6a: Effect of Atrazine on 42-Day Vegetative Vigor (Test 2)

Species Results summary for height (lbs ai/A) 

height 

(cm)

NOEC* IC10 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 20.2-23.8 0.25 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Carrot1 29-35.4 0.25 0.348 0.259-

0.482 

>0.50 N/A >0.50 N/A N/A N/A 

Corn2 131-153 1.0 2.2 1.6-14.3 >25 N/A >25 N/A N/A N/A 

Cucumber3 61.5-74.1 0.010 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Lettuce 24-30.7 0.25 0.152 0.098-ND >0.25 N/A >0.25 N/A N/A N/A 

Oat4 35.3-65.9 0.25 0.078 0.060-

0.187 

0.214 0.046-ND >0.98 N/A N/A N/A 

Onion5 28-42.6 0.25 0.321 0.169-

0.473 

0.865 0.277-ND >2.5 N/A N/A N/A 

Ryegrass6 21.6-42.9 5.0 5.887 5.441-

7.047 

7.404 6.155-ND >9.8 N/A N/A N/A 

Soybean7 44.4-115 <0.0050/ 

0.00089** 

0.0028 0.0016-

0.013 

0.027 0.018-

0.034 

0.098 0.081-

0.143 

N/A N/A 

Tomato8 62.1-108 0.098 0.107 0.0037-

0.125 

0.161 0.125-

0.214 

>0.25 N/A N/A N/A 

ND- Not determined. NC- Not calculable. 

*NOEC and all significant inhibitions determined by Dunnett’s Multiple Comparison Test (p<0.05), unless specified otherwise 

**Since NOEC is lower than <lowest application rate, the EC05 is provided (NOEC/EC05). 

1 Inhibition in carrot height of 18% at 0.50 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05). 

2 Inhibition in corn height of 13, 13 and 12% at 2.5, 9.8 and 25 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, p<0.05). 

3 Inhibition in cucumber height of 12, 16 to 12% at 0.025, 0.050 and 0.098 lb ai/A (Wilcoxon’s Test with Bonferroni-Holm’s Adjustment, 

p<0.05); 100% mortality at the highest concentration (0.50 lb ai/A). 

4 Inhibition in oat height of 38% at 0.50 lb ai/A; 100% mortality at the highest concentrations (2.5 lb ai/A). 

5 Inhibition in onion height of 18, 33 and 20% at 0.50, 0.98 and 2.5 lb ai/A. 

6 Inhibition in ryegrass height of 40% at 10 lb ai/A. 

7 Inhibition in soybean height of 14 to 62% at all test concentrations. 

8 Inhibition in tomato height of 42% at 0.25 lb ai/A. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 22 of 40 

Table 6b: Effect of Atrazine on 42-Day Vegetative Vigor (Test 2)

Species Results summary for survival (lbs ai/A) 

% NOEC* EC10 95%CI EC25 95%CI EC50 95%CI slope 95%CI 

Cabbage 98-100 0.25 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Carrot1 35-100 0.25 0.268 0.25-0.277 0.312 0.294-

0.339 

0.419 0.375-

0.482 

N/A N/A 

Corn 100 25 >25 N/A >25 N/A >25 N/A N/A N/A 

Cucumber2 0-100 0.098 0.086 0.064-

0.116 

0.125 0.089-

0.169 

0.223 0.169-

0.285 

N/A N/A 

Lettuce3 8-100 0.050 0.068 0.061-

0.098 

0.098 0.081-

0.116 

0.143 0.125-

0.161 

N/A N/A 

Oat4 0-100 0.098 0.107 0.074-0.33 0.205 0.107-

0.366 

0.384 0.143-

0.749 

N/A N/A 

Onion5 5-100 0.50 0.50 0.223-

0.544 

0.589 0.535-

0.633 

0.785 0.705-

0.865 

N/A N/A 

Ryegrass6 10-100 0.98 1.338 0.981-3.30 2.319 1.16-3.836 3.657 1.873-

6.690 

N/A N/A 

Soybean7 60-100 0.098 0.116 0.086-

0.134 

0.169 0.143-

0.250 

>0.25 N/A N/A N/A 

Tomato8 33-100 0.098 0.107 0.098-

0.116 

0.134 0.125-

0.161 

0.196 0.169-ND N/A N/A 

ND- Not determined. NC- Not calculable. 

*NOEC and all significant inhibitions determined by Fisher’s Exact Test with Bonferroni-Holm’s Adjustment (p<0.05).

1 Inhibition in carrot survival of 65% at 0.50 lb ai/A. 

2 Inhibition in cucumber survival of 55, and 100% at 0.25 and 0.50 lb ai/A. 

3 Inhibition in lettuce survival of 23 and 93% at 0.098 and 0.25 lb ai/A. 

4 Inhibition in oat survival of 30, 63, 85 and 100% at 0.25, 0.50, 0.98 and 2.5 lb ai/A. 

5 Inhibition in onion survival of 70 and 95% at 0.98 and 2.5 lb ai/A. 

6 Inhibition in ryegrass survival of 28, 68 and 90% at 2.5, 5.0 and 10 lb ai/A. 

7 Inhibition in soybean survival of 40% at 0.25 lb ai/A. 

8 Inhibition in tomato survival of 68% at 0.25 lb ai/A. 

Plant Injury Index*; Test 2

Control Cabbage Carrot Corn Cucumber Lettuce Oat Onion Ryegrass Soybean Tomato Formulation 

Blank

0 0-100 0-100 0 0-100 0-100 0-100 0-100 0-100 0-100 0-100 N/A 

* The health rating, including morphological abnormalities ranges from 0 to 100, where 0 indicates no injury or abnormality and 100 indicates 

complete effect (dead plant). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 23 of 40 

Table 7: Effect of Atrazine on 21-Day of the 42-Day Vegetative Vigor (Test 2a)

Species Results summary for height (lbs ai/A) 

height 

(cm)

NOEC* IC10 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 18.7-20.8 0.25 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Carrot1 10.4-24.4 <0.0098/ 

0.0023** 

0.017 0.0045-

0.054 

0.125 0.089-

0.178 

0.395 0.312-ND N/A N/A 

Corn2 101-123 1.0 2.3 1.9-7.7 >25 N/A >25 N/A N/A N/A 

Cucumber3 27.5-46 0.010 0.016 0.010-

0.025 

0.054 0.030-

0.075 

>0.25 N/A N/A N/A 

Lettuce4 9.67-26.2 0.025 0.031 0.0089-

0.051 

0.064 0.056-

0.072 

0.143 0.107-ND N/A N/A 

Oat5 22-59.3 0.098 0.085 0.056-

0.161 

0.178 0.072-

0.348 

1.338 0.029-

1.962 

N/A N/A 

Onion6 11-27.1 0.0037 0.023 0.005-

0.152 

0.196 0.125-

0.294 

0.705 0.580-1.07 N/A N/A 

Ryegrass7 12.6-35.3 0.98 1.07 0.562-

1.784 

2.944 1.784-

6.244 

6.69 2.408-ND N/A N/A 

Soybean8 36.1-112 <0.00050/

0.00088** 

0.0027 0.0013-

0.0011 

0.027 0.018-

0.032 

0.086 0.070-

0.116 

N/A N/A 

Tomato9 25.8-71.9 0.010 0.020 0.0078-

0.098 

0.125 0.107-

0.134 

0.196 0.178-

0.214 

N/A N/A 

ND- Not determined. NC- Not calculable. All inhibitions reported below were determined by the reviewer. 

*NOEC determined by Dunnett’s Multiple Comparison Test (p<0.05).

**Since NOEC is lower than <lowest application rate, the EC05 is provided (NOEC/EC05). 

1 Inhibition carrot height of 10 to 58% at all test concentrations. 

2 Inhibition corn height, inhibitions of 11, 8, 13 and 15% at 2.5, 5.0, 9.8 and 25 lb ai/A. 

3 Inhibition cucumber height, inhibitions of 18, 24, 35 and 40% at 0.025, 0.050, 0.098 and 0.25 lb ai/A. 

4 Inhibition lettuce height, inhibitions of 8, 14, 42 and 63% at 0.025, 0.050, 0.098, 0.25 lb ai/A. 

5 Inhibition oat height, inhibitions of 28, 43, 42 and 59% at 0.25, 0.50, 0.98 and 2.5 lb ai/A. 

6 Inhibition onion height, inhibitions of 12 to 59% at all test concentrations. 

7 Inhibition ryegrass height, inhibition of 18, 38 and 62% at 2.5, 5.0 and 10 lb ai/A. 

8 Inhibition soybean height, inhibition of 14 to 68% at all test concentrations. 

9 Inhibition in tomato height, inhibitions of 14, 11, 12 and 64% at 0.025, 0.050, 0.098 and 0.25 lb ai/A. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 24 of 40 

Table 7a: Effect of Atrazine on 21-Day of the 42-Day Vegetative Vigor (Test 2a)

Species Results summary for survival (lbs ai/A) 

% NOEC* EC10 95%CI EC25 95%CI EC50 95%CI slope 95%CI 

Cabbage ND 0.25 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Carrot ND 0.25 >0.25 N/A >0.25 N/A >0.25 N/A N/A N/A 

Corn ND 25 >25 N/A >25 N/A >25 N/A N/A N/A 

Cucumber ND 0.098 0.098 0.062-

0.116 

0.143 0.084-

0.178 

0.25 0.187-

0.294 

N/A N/A 

Lettuce ND 0.098 0.078 0.064-

0.107 

0.107 0.089-

0.125 

0.152 0.134-

0.161 

N/A N/A 

Oat ND 0.25 0.294 0.259-

0.598 

0.419 0.294-

0.705 

0.696 0.375-

1.070 

N/A N/A 

Onion ND 0.50 0.50 0.196-

0.312 

0.589 0.526-

0.642 

0.785 0.714-

0.865 

N/A N/A 

Ryegrass ND 1.0 1.606 1.070-3.39 2.944 1.695-

6.601 

4.995 2.765-

9.812 

N/A N/A 

Soybean ND 0.098 0.116 0.107-

0.134 

0.169 0.143-

0.250 

>0.25 N/A N/A N/A 

Tomato ND 0.098 0.107 0.098-

0.116 

0.134 0.125-

0.161 

0.098 0.169-ND N/A N/A 

ND- Not determined. NC- Not calculable. Raw survival data for day 21 of the 42 day study was not reported, therefore, inhibitions could not be 

determined by the reviewer. 

*NOEC and determined by Fisher’s Exact Test with Bonferroni-Holm’s Adjustment (p<0.05).

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 25 of 40 

C. VERIFICATION OF STATISTICAL RESULTS BY THE REVIEWER: 

All analyses were conducted comparing treated to the negative control. These analyses were conducted using 

CETIS version 1.8.7.12 and backend settings approved for use by EFED on 10/10/15. Data for each endpoint 

were tested to determine if their distributions were normal and if their variances were homogeneous using 

Shapiro-Wilk’s and Levene’s tests, respectively. Data that satisfied these assumptions were subjected to 

Dunnett’s and William’s tests, and data that did not satisfy these assumptions were subjected to the nonparametric Mann Whitney-U and Jonckheere’s tests. Measured concentrations were used for all analyses. 

Linear (survival and emergence) and nonlinear (height and dry weight) regression models were used to interpret 

EC/ICx values. 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 26 of 40 

Table 8: Effect of Atrazine on 21-Day Vegetative Vigor (Test 1)

Species Results summary for biomass (lbs ai/A) 

weight (g) NOEC IC05 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage1 0.777-2.08 0.047 0.0148 N/A0.0257 0.059 0.0425-

0.0784 

0.154 0.126-

0.189 

N/A N/A 

Carrot2 0.0752-0.438 <0.0095 0.0123 N/A0.0226 0.0544 0.0402-

0.0709 

0.153 0.129-

0.182 

N/A N/A 

Corn3 2.84-3.55 0.91 0.37 N/A-4.62 102 0.817-

1940 

NC N/A N/A N/A 

Cucumber4 0.796-3.83 <0.0099 0.00132 N/A0.00836 0.0145 0.00586-

0.0297 

0.0764 0.0498-

0.117 

N/A N/A 

Lettuce5 0.111-1.07 0.0044 0.00653 N/A-0.011 0.0215 0.0164-

0.0273 

0.0494 0.0421-

0.058 

N/A N/A 

Oat6 0.0798-0.668 0.45 0.211 0.105-

0.372 

0.354 0.234-

0.558 

0.773 0.471-2.5 N/A N/A 

Onion7 0.0043-0.0473 <0.044 0.00673 N/A0.0219 0.0379 0.0217-

0.0599 

0.126 0.0952-

0.167 

N/A N/A 

Ryegrass8 0.0479-0.273 0.22 0.0292 N/A-0.168 0.243 0.0994-

0.487 

1.06 0.70-1.61 N/A N/A 

Soybean9 0.372-2.56 0.0074 0.00422 N/A0.00857 0.018 0.0125-

0.0245 

0.0491 0.0398-

0.0606 

N/A N/A 

Tomato10 0.602-2.08 0.0074 0.00572 N/A0.0122 0.0286 0.0188-

0.0409 

0.0876 0.0694-

0.111 

N/A N/A 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in cabbage weight, inhibitions of 33 and 55% at the 0.096 and 0.22 lb ai/A (Williams test, p<0.05). 

2 Significant decrease in carrot weight, inhibitions of 10 to 83% at all test concentrations, 0.0095 to 0.45 lb ai/A (Williams test, p<0.05). 

3 Significant decrease in corn weight, inhibitions of 18 and 20% at 2.4 and 24 lb ai/A (Dunnetts test, p<0.05). 

4 Significant decrease in cucumber weight, inhibitions of 17 to 79% at all test concentrations, 0.0099 to 0.51 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05). 

5 Significant decrease in lettuce weight, inhibitions of 15 to 90% at 0.0095 to 0.22 lb ai/A (Williams test, p<0.05). 

6 Significant decrease in oat weight, inhibitions of 74% at 0.91 lb ai/A (Williams test, p<0.05); 100% mortality at highest concentrations (2.4 lb 

ai/A). 

7 Significant decrease in onion weight, inhibitions of 35 to 91% at all test concentrations, 0.044 to 2.3 lb ai/A (Williams test, p<0.05). 

8 Significant decrease in ryegrass weight, inhibitions of 41 to 83% at 0.51 to 9.6 lb ai/A (Williams test, p<0.05). 

9 Significant decrease in soybean weight, inhibitions of 34, 42, 73 and 86% at 0.021, 0.047, 0.094 and 0.24 lb ai/A (Williams test, p<0.05). 

10 Significant decrease in tomato weight, inhibitions of 24, 23, 57 and 70% at 0.021, 0.047, 0.094 and 0.24 lb ai/A (Williams test, p<0.05). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 27 of 40 

Table 8a: Effect of Atrazine on 21-Day Vegetative Vigor (Test 1)

Species Results summary for height (lbs ai/A) 

height 

(cm)

NOEC IC05 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 21-21.8 0.22 >0.22 N/A >0.22 N/A >0.22 N/A N/A N/A 

Carrot1 11.9-24.3 0.0095 0.0411 0.0192-

0.0621 

0.19 0.156-

0.229 

0.552 0.435-0.70 N/A N/A 

Corn2 104-117 4.5 3.26 0.874-8.15 428 3-6880 12700 0.0751-

2.13E+09 

N/A N/A 

Cucumber3 17.8-48.6 0.0099 0.0042 N/A0.0134 0.0439 0.0272-

0.0668 

0.224 0.156-

0.323 

N/A N/A 

Lettuce4 11.5-26.5 0.024 0.0182 0.0104-

0.0253 

0.0685 0.0579-

0.0801 

0.172 0.149-0.20 N/A N/A 

Oat5 27.3-60.7 0.24 0.312 0.181-

0.471 

0.665 0.461-

0.941 

1.57 0.78-4.1 N/A N/A 

Onion6 11.2-25.8 <0.044 0.00995 N/A0.0403 0.13 0.0739-

0.213 

0.776 0.523-1.15 N/A N/A 

Ryegrass7 21.1-36.4 0.51 0.196 N/A-0.586 2.76 1.78-4.09 17.3 8.43-35.5 N/A N/A 

Soybean8 40.8-113 0.0074 0.00847 0.00357-

0.0133 

0.0424 0.0339-

0.052 

0.13 0.113-

0.149 

N/A N/A 

Tomato9 40.2-68.3 0.0074 0.0212 0.00452-

0.0376 

0.114 0.0853-

0.147 

0.366 0.234-0.57 N/A N/A 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in carrot height, inhibition of 8 to 51% at 0.024 to 0.45 lb ai/A (Williams test, p<0.05). 

2 Significant decrease in corn height, inhibitions of 7 and 9% at 9.1 and 24 lb ai/A (Williams test, p<0.05). 

3 Significant decrease in cucumber height, inhibitions of 22 to 63% at 0.022 to 0.51 lb ai/A (Williams test, p<0.05). 

4 Significant decrease in lettuce height, inhibitions of 14, 34 and 56% at 0.044, 0.092 and 0.22 lb ai/A (Jonckheere-Terpstra Step-Down test, 

p<0.05). 

5 Significant decrease in oat height, inhibitions of 26 and 35% at 0.45 and 0.91 lb ai/A (Williams test, p<0.05); 100% mortality at highest 

concentrations (2.4 lb ai/A). 

6 Significant decrease in onion height, inhibitions of 13 to 57% at all test concentrations (Jonckheere-Terpstra Step-Down test, p<0.05). 

7 Significant decrease in ryegrass height, inhibition of 14, 28, 25 and 40% at 0.97, 2.4, 4.6 and 9.6 lb ai/A (Williams test, p<0.05). 

8 Significant decrease in soybean height, inhibition of 12, 28, 47 and 64% at 0.021, 0.047, 0.094 and 0.24 lb ai/A (Williams test, p<0.05). 

9 Significant decrease in tomato height, inhibitions of 11, 8, 24 and 41% at 0.021, 0.047, 0.094 and 0.24 lb ai/A (Jonckheere-Terpstra Step-Down 

test, p<0.05). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 28 of 40 

Table 8b: Effect of Atrazine on 21-Day Vegetative Vigor (Test 1)

Species Results summary for survival (lbs ai/A) 

% NOEC EC05 95%CI EC25 95%CI EC50 95%CI slope 95%CI 

Cabbage 100 0.22 >0.22 N/A >0.22 N/A >0.22 N/A N/A N/A 

Carrot1 53-100 0.22 0.221 0.134-

0.272 

0.341 0.279-

0.398 

0.463 0.397-

0.609 

5.12 2.73-7.5 

Corn 100 24 >24 N/A >24 N/A >24 N/A N/A N/A 

Cucumber2 13-100 0.022 0.0452 0.0291-

0.0607 

0.104 0.0806-

0.127 

0.185 0.151-

0.229 

2.69 2.06-3.32 

Lettuce3 25-100 0.044 0.0704 0.0487-

0.0875 

0.113 0.0919-

0.132 

0.157 0.134-

0.186 

4.73 3.26-6.21 

Oat4 0-100 0.047 0.204 0.0955-

0.296 

0.392 0.26-0.514 0.617 0.467-

0.841 

3.42 2.06-4.77 

Onion5 10-100 0.092 0.189 0.102-

0.271 

0.407 0.287-

0.525 

0.694 0.539-

0.912 

2.91 2.0-3.83 

Ryegrass6 45-100 0.97 0.895 0.459-1.33 3.14 2.32-4.15 7.5 5.51-11.8 1.78 1.25-2.31 

Soybean7 75-100 0.094 0.104 0.0466-

0.143 

0.236 0.175-

0.424 

0.416 0.279-1.42 2.74 1.18-4.3 

Tomato8 45-100 0.094 0.0797 0.0491-

0.103 

0.145 0.115-

0.176 

0.219 0.181-

0.291 

3.74 2.37-5.11 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in carrot survival, inhibition of 48% at 0.45 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

2 Significant decrease in cucumber survival, inhibition of 8, 20, 60 and 88% at 0.047, 0.096, 0.22 and 0.51 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05). 

3 Significant decrease in lettuce survival, inhibition of 15 and 75% at 0.092 and 0.22 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

4 Significant decrease in oat survival, inhibition of 3, 5, 30, 70 and 100% at 0.094, 0.24, 0.45, 0.91 and 2.4 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05). 

5 Significant decrease in onion survival, inhibition of 5, 33, 70 and 90% at 0.22, 0.45, 0.94 and 2.3 lb ai/A (Jonckheere-Terpstra Step-Down test, 

p<0.05). 

6 Significant decrease in ryegrass survival, inhibition of 25, 35 and 55% at 2.4, 4.6 and 9.6 lb ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). 

7 Significant decrease in soybean survival, inhibition of 25% at 0.24 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

8 Significant decrease in tomato survival, inhibition of 55% at 0.24 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

Plant Injury Index*; Test 1

Control Cabbage Carrot Corn Cucumber Lettuce Oat Onion Ryegrass Soybean Tomato Formulation 

Blank

0 0-10 0-100 0 0-100 0-100 0-100 0-100 0-100 0-100 0-100 N/A 

* The health rating, including morphological abnormalities ranges from 0 to 100, where 0 indicates no injury or abnormality and 100 indicates 

complete effect (dead plant). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 29 of 40 

Table 9: Effect of Atrazine on 42-Day Vegetative Vigor (Test 2)

Species Results summary for biomass (lbs ai/A) 

weight (g) NOEC IC05 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 2.85-3.51 0.22 >0.22 N/A >0.22 N/A >0.22 N/A N/A N/A 

Carrot1 1.44-2.02 <0.0095 0.234 N/A-0.393 0.461 0.32-

0.602 

0.739 0.13-4.2 N/A N/A 

Corn2 7.34-10.6 0.91 0.0358 N/A-0.756 5.83 2.2-13.9 201 10.3-3920 N/A N/A 

Cucumber3 4.61-6.82 <0.0099 NC N/A NC N/A NC N/A N/A N/A 

Lettuce4 2.91-4.92 0.0095 0.00844 N/A-0.021 0.061 0.0379-

0.0919 

0.241 0.111-

0.524 

N/A N/A 

Oat5 0.227-1.23 0.24 NC N/A NC N/A NC N/A N/A N/A 

Onion6 0.117-0.455 0.092 0.0145 N/A0.0594 0.0996 0.049-

0.176 

0.381 0.266-

0.546 

N/A N/A 

Ryegrass7 0.152-1.18 4.6 NC N/A NC N/A NC N/A N/A N/A 

Soybean8 0.578-5.25 <0.0044 0.000419 N/A0.00138 0.00397 0.00252-

0.00594 

0.019 0.015-

0.0239 

N/A N/A 

Tomato9 2.94-6.35 0.094 0.0411 N/A0.0739 0.119 0.0765-

0.168 

0.249 0.165-

0.375 

N/A N/A 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in carrot weight, inhibitions of 10, 9, 7 and 29% at 0.0095, 0.044, 0.092 and 0.45 lb ai/A (Mann-Whitney U Two-Sample 

test, p<0.05). 

2 Significant decrease in corn weight, inhibitions of 29, 29 and 31% at 2.4, 9.1 and 24 lb ai/A (Dunnetts test, p<0.05). 

3 Significant decrease in cucumber weight, inhibitions of 13, 26, 29, 33 and 9% at 0.0099, 0.022, 0.047, 0.096 and 0.22 lb ai/A (Mann-Whitney U 

Two-Sample test, p<0.05); 100% mortality at the highest concentration (0.51 lb ai/A). 

4 Significant decrease in lettuce weight, inhibitions of 11, 16, 36 and 41% at 0.024, 0.044, 0.092 and 0.22 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05). 

5 Significant decrease in oat weight, inhibitions of 75% at 0.45 lb ai/A (Dunnetts test, p<0.05); 100% mortality at the highest concentrations (2.4 

lb ai/A). 

6 Significant decrease in onion weight, inhibitions of 35, 57, 74 and 70% at 0.22, 0.45, 0.94 and 2.3 lb ai/A (Williams test, p<0.05). 

7 Significant decrease in ryegrass weight, inhibitions of 83% at 9.6 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

8 Significant decrease in soybean weight, inhibitions of 31 to 89% at all test concentrations (Williams test, p<0.05). 

9 Significant decrease in tomato weight, inhibitions of 51% at 0.24 lb ai/A (Dunnetts test, p<0.05). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 30 of 40 

Table 9a: Effect of Atrazine on 42-Day Vegetative Vigor (Test 2)

Species Results summary for height (lbs ai/A) 

height 

(cm)

NOEC IC05 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 20.2-23.8 0.22 >0.22 N/A >0.22 N/A >0.22 N/A N/A N/A 

Carrot1 29-35.4 0.22 0.423 0.40-0.434 0.463 0.453-

0.472 

0.493 0.487-

0.499 

N/A N/A 

Corn2 131-153 0.91 0.719 0.0469-

3.12 

157 8.08-1350 6670 8.91-

4990000 

N/A N/A 

Cucumber3 61.5-74.1 0.0099 NC N/A NC N/A NC N/A N/A N/A 

Lettuce 24-30.7 0.22 0.128 N/A-0.211 0.252 0.122-

0.374 

NC N/A N/A N/A 

Oat4 35.3-65.9 0.24 0.028 N/A-0.141 0.317 0.144-

0.605 

1.71 0.306-9.57 N/A N/A 

Onion5 28-42.6 0.22 0.0547 0.0000945

-0.158 

0.929 0.55-1.48 6.65 1.77-24.9 N/A N/A 

Ryegrass6 21.6-42.9 4.6 8.31 N/A-8.97 9.16 8.3-9.68 9.79 9.65-9.94 N/A N/A 

Soybean7 44.4-115 <0.0044 0.00162 0.000189-

0.00372 

0.0193 0.0143-

0.0254 

0.108 0.0893-

0.131 

N/A N/A 

Tomato8 62.1-108 0.094 0.132 N/A-0.221 0.202 N/A-0.272 0.272 0.203-

0.366 

N/A N/A 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in carrot height, inhibition of 18% at 0.45 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

2 Significant decrease in corn height, inhibitions of 13, 13 and 12% at 2.4, 9.1 and 24 lb ai/A (Dunnetts test, p<0.05). 

3 Significant decrease in cucumber height, inhibitions of 12, 16 to 12% at 0.022, 0.047 and 0.096 lb ai/A (Mann-Whitney U Two-Sample test, 

p<0.05); 100% mortality at the highest concentration (0.51 lb ai/A). 

4 Significant decrease in oat height, inhibitions of 38% at 0.45 lb ai/A (Dunnetts test, p<0.05); 100% mortality at the highest concentrations (2.4 

lb ai/A). 

5 Significant decrease in onion height, inhibitions of 18, 32 and 20% at 0.45, 0.94 and 2.3 lb ai/A (Dunnetts test, p<0.05). 

6 Significant decrease in ryegrass height, inhibition of 40% at 9.6 lb ai/A (Dunnetts test, p<0.05). 

7 Significant decrease in soybean height, inhibition of 14 to 62% at all test concentrations (Williams test, p<0.05). 

8 Significant decrease in tomato height, inhibitions of 42% at 0.24 lb ai/A (Dunnetts test, p<0.05). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 31 of 40 

Table 9b: Effect of Atrazine on 42-Day Vegetative Vigor (Test 2)

Species Results summary for survival (lbs ai/A) 

% NOEC EC05 95%CI EC25 95%CI EC50 95%CI slope 95%CI 

Cabbage 98-100 0.22 >0.22 N/A >0.22 N/A >0.22 N/A N/A N/A 

Carrot1 35-100 0.22 0.22 0.155-

0.263 

0.31 0.259-0.35 0.393 0.348-

0.453 

6.54 4.08-8.99 

Corn 100 24 >24 N/A >24 N/A >24 N/A N/A N/A 

Cucumber2 0-100 0.047 0.0828 0.0592-

0.103 

0.134 0.11-0.157 0.188 0.162-0.22 4.62 3.39-5.84 

Lettuce3 8-100 0.044 0.0662 0.0496-

0.0793 

0.0963 0.0807-

0.11 

0.125 0.109-

0.144 

5.98 4.24-7.71 

Oat4 0-100 0.047 0.0919 0.0452-

0.138 

0.204 0.136-0.27 0.355 0.268-0.47 2.8 1.91-3.7 

Onion5 5-100 0.45 0.278 0.193-

0.353 

0.507 0.41-0.60 0.771 0.654-

0.915 

3.71 2.79-4.63 

Ryegrass6 10-100 0.97 0.983 0.457-1.47 2.08 1.37-2.76 3.51 2.64-4.76 2.97 1.9-4.04 

Soybean7 60-100 0.094 0.098 0.0536-

0.128 

0.182 0.143-

0.232 

0.28 0.222-

0.446 

3.6 1.94-5.26 

Tomato8 33-100 0.094 0.106 0.07-0.131 0.155 0.123-

0.179 

0.201 0.173-

0.234 

5.94 3.71-8.17 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in carrot survival, inhibition of 65% at 0.45 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

2 Significant decrease in cucumber survival, inhibition of 13, 55, and 100% at 0.096, 0.22 and 0.51 lb ai/A (Jonckheere-Terpstra Step-Down test, 

p<0.05). 

3 Significant decrease in lettuce survival, inhibition of 23 and 93% at 0.092 and 0.22 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

4 Significant decrease in oat survival, inhibition of 8, 30, 63, 85 and 100% at 0.094, 0.24, 0.45, 0.91 and 2.4 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05). 

5 Significant decrease in onion survival, inhibition of 70 and 95% at 0.94 and 2.3 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

6 Significant decrease in ryegrass survival, inhibition of 28, 68 and 90% at 2.4, 4.6 and 9.6 lb ai/A (Jonckheere-Terpstra Step-Down test, p<0.05). 

7 Significant decrease in soybean survival, inhibition of 40% at 0.24 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

8 Significant decrease in tomato survival, inhibition of 68% at 0.24 lb ai/A (Mann-Whitney U Two-Sample test, p<0.05). 

Plant Injury Index*; Test 2

Control Cabbage Carrot Corn Cucumber Lettuce Oat Onion Ryegrass Soybean Tomato Formulation 

Blank

0 0-100 0-100 0 0-100 0-100 0-100 0-100 0-100 0-100 0-100 N/A 

* The health rating, including morphological abnormalities ranges from 0 to 100, where 0 indicates no injury or abnormality and 100 indicates 

complete effect (dead plant). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 32 of 40 

Table 10: Effect of Atrazine on 21-Day of the 42-Day Vegetative Vigor (Test 2a)

Species Results summary for height (lbs ai/A) 

height 

(cm)

NOEC IC05 95%CI IC25 95%CI IC50 95%CI slope 95%CI 

Cabbage 18.7-20.8 0.22 >0.22 N/A >0.22 N/A >0.22 N/A N/A N/A 

Carrot1 10.4-24.4 <0.0095 0.0285 0.0125-

0.0439 

0.135 0.108-

0.165 

0.398 0.33-0.48 N/A N/A 

Corn2 101-123 0.91 1.22 0.326-2.82 54.9 19.4-132 773 67.1-8910 N/A N/A 

Cucumber3 27.5-46 0.0099 0.00341 N/A0.0114 0.0509 0.0331-

0.0751 

0.333 0.177-

0.626 

N/A N/A 

Lettuce4 9.67-26.2 0.0095 0.019 0.0107-

0.0259 

0.0601 0.051-

0.0699 

0.134 0.116-

0.154 

N/A N/A 

Oat5 22-59.3 0.094 0.0232 N/A0.0835 0.201 0.111-

0.332 

0.898 0.572-1.41 N/A N/A 

Onion6 11-27.1 <0.044 0.0133 0.00011-

0.0325 

0.146 0.106-

0.195 

0.774 0.627-

0.955 

N/A N/A 

Ryegrass7 12.6-35.3 0.97 0.848 N/A-1.62 2.78 1.7-4.08 6.35 4.83-8.35 N/A N/A 

Soybean8 36.1-112 <0.0044 0.00219 0.000499-

0.00429 

0.0194 0.0151-

0.0244 

0.0882 0.076-

0.102 

N/A N/A 

Tomato9 25.8-71.9 0.0074 0.0873 N/A-0.109 0.145 0.12-0.168 0.206 0.189-

0.223 

N/A N/A 

ND- Not determined. NC- Not calculable. 

1 Significant decrease in carrot height, inhibition of 10 to 58% at all test concentrations (Jonckheere-Terpstra Step-Down test, p<0.05). 

2 Significant decrease in corn height, inhibitions of 11, 8, 13 and 15% at 2.4, 4.5, 9.1 and 24 lb ai/A (Mann-Whitney U Two-Sample test, 

p<0.05). 

3 Significant decrease in cucumber height, inhibitions of 18, 24, 35 and 40% at 0.022, 0.047, 0.096 and 0.22 lb ai/A (Jonckheere-Terpstra StepDown test, p<0.05). 

4 Significant decrease in lettuce height, inhibitions of 8, 14, 42 and 63% at 0.024, 0.044, 0.092, 0.22 lb ai/A (Williams test, p<0.05). 

5 Significant decrease in oat height, inhibitions of 28, 43, 42 and 59% at 0.24, 0.45, 0.91 and 2.4 lb ai/A (Williams test, p<0.05). 

6 Significant decrease in onion height, inhibitions of 12 to 59% at all test concentrations (Williams test, p<0.05). 

7 Significant decrease in ryegrass height, inhibition of 18, 38 and 62% at 2.4, 4.6 and 9.6 lb ai/A (Williams test, p<0.05). 

8 Significant decrease in soybean height, inhibition of 14 to 68% at all test concentrations (Williams test, p<0.05). 

9 Significant decrease in tomato height, inhibitions of 14, 11, 12 and 64% at 0.021, 0.047, 0.094 and 0.24 lb ai/A (Dunnetts test, p<0.05). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 33 of 40 

Test 1, 21 days 

Most sensitive monocot: Onion, based on dry weight* 

EC50/IC50: 0.126 lb ai/A 95% C.I.: 0.0952-0.167 lb ai/A 

EC25/IC25: 0.0379 lb ai/A 95% C.I.: 0.0217-0.0599 lb ai/A 

EC05/IC05: 0.00673 lb ai/A 95% C.I.: N/A-0.0219 lb ai/A 

NOEC: <0.044 lb ai/A 

Slope: N/A 95% C.I.: N/A 

 * IC25 value was slightly less than the lowest concentration tested (0.044 lb ai/A). 

Most sensitive dicot: Cucumber, based on dry weight 

EC50/IC50: 0.0764 lb ai/A 95% C.I.: 0.0498-0.117 lb ai/A 

EC25/IC25: 0.0145 lb ai/A 95% C.I.: 0.00586-0.0297 lb ai/A 

EC05/IC05: 0.00132 lb ai/A 95% C.I.: N/A-0.00836 lb ai/A 

NOEC: <0.0099 lb ai/A 

Slope: N/A 95% C.I.: N/A 

Test 2, 42 days 

Most sensitive monocot: Onion, based on dry weight 

EC50/IC50: 0.381 lb ai/A 95% C.I.: 0.266-0.546 lb ai/A 

EC25/IC25: 0.0996 lb ai/A 95% C.I.: 0.049-0.176 lb ai/A 

EC05/IC05: 0.0145 lb ai/A 95% C.I.: N/A-0.0594 lb ai/A 

NOEC: 0.092 lb ai/A 

Slope: N/A 95% C.I.: N/A 

Most sensitive dicot: Soybean, based on dry weight* 

EC50/IC50: 0.019 lb ai/A 95% C.I.: 0.015-0.0239 lb ai/A 

EC25/IC25: 0.00397 lb ai/A 95% C.I.: 0.00252-0.00594 lb ai/A 

EC05/IC05: 0.000419 lb ai/A 95% C.I.: N/A-0.00138 lb ai/A 

NOEC: <0.0044 lb ai/A 

Slope: N/A 95% C.I.: N/A 

* IC25 value was slightly less than the lowest concentration tested (0.0044 lb ai/A). 

 

Test 2a, 21 days of 42 days 

Most sensitive monocot: Onion, based on height (only endpoint analyzed) 

EC50/IC50: 0.774 lb ai/A 95% C.I.: 0.627-0.955 lb ai/A 

EC25/IC25: 0.146 lb ai/A 95% C.I.: 0.106-0.195 lb ai/A 

EC05/IC05: 0.0133 lb ai/A 95% C.I.: 0.00011-0.0325 lb ai/A 

NOEC: <0.044 lb ai/A 

Slope: N/A 95% C.I.: N/A 

Most sensitive dicot: Soybean, based on height (only endpoint analyzed) 

EC50/IC50: 0.0882 lb ai/A 95% C.I.: 0.076-0.102 lb ai/A 

EC25/IC25: 0.0194 lb ai/A 95% C.I.: 0.0151-0.0244 lb ai/A 

EC05/IC05: 0.00219 lb ai/A 95% C.I.: 0.000499-0.00429 lb ai/A 

NOEC: <0.0044 lb ai/A 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 34 of 40 

Slope: N/A 95% C.I.: N/A 

D. STUDY DEFICIENCIES: 

1. The physico-chemical properties of the test material were not reported. 

2. Survival at 21 days in the 42 day study was analyzed by the study author, however raw data were not 

provided. Therefore, the reviewer could not verify the statistical analysis or results. 

3. The IC25 value was slightly less than the lowest concentration tested for the most sensitive monocot for 

Test 1, onion, and the most sensitive dicot for Test 2, soybean. EPA recommends that test concentrations 

bracket the most sensitive NOEC and IC25 values. 

4. In the Test 2, the 42 day study, the most sensitive endpoint for carrot, cucumber, oat and ryegrass was 

survival. The study is designed to capture sub-lethal effects, therefore, survival is not expected to be the 

most sensitive endpoint. 

E. REVIEWER’S COMMENTS: The reviewer and study author results are in general agreement. Slight 

differences in EC25 values resulted in different reviewer and study author most sensitive monocot for the Test 2a, 21 

day of 42 day study. There were also some differences in NOEC and ECx values. These slight discrepancies are 

likely due to the reviewer using measured concentrations and differences in statistical analysis methods. 

Test 1, 21 days 

The most sensitive monocot, based on the study author's results, was onion based on dry weight with NOAEC 

and EC25 values of <0.050/0.00066 lb ai/A (<NOEC/EC05) and 0.013 lb ai/A, respectively; the most sensitive 

dicot was cucumber based on dry weight with NOAEC and EC25 values of <0.0098/0.0010 (<NOEC/EC05) and 

0.014 lb ai/A, respectively. The most sensitive monocot, based on the reviewer’s results, was onion based on 

dry weight with NOAEC and EC25 values of <0.044 lb ai/A and 0.0379 lb ai/A, respectively; the most sensitive 

dicot was cucumber based on dry weight with NOAEC and EC25 values of <0.0099 and 0.0145 lb ai/A, 

respectively. 

Test 2, 42 days 

The most sensitive monocot, based on the study author's results, was onion based on dry weight with NOAEC 

and EC25 values of 0.050 lb ai/A (NOEC) and 0.062 lb ai/A, respectively; the most sensitive dicot was soybean 

based on dry weight with NOAEC and EC25 values of <0.0050/0.00032 (<NOEC/EC05) and 0.0032 lb ai/A, 

respectively. The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with 

NOAEC and EC25 values of 0.092 lb ai/A and 0.0996 lb ai/A, respectively; the most sensitive dicot was 

soybean based on dry weight with NOAEC and EC25 values of <0.0044 and 0.00397 lb ai/A, respectively. 

Test 2a, 21 days of 42 days 

The most sensitive monocot, based on the study author's results, was oat based on height with NOAEC and 

EC25 values of 0.098 lb ai/A and 0.178 lb ai/A, respectively; the most sensitive dicot was soybean based on 

height with NOAEC and EC25 values of <0.00050/0.00088 (<NOEC/EC05) and 0.027 lb ai/A, respectively. The 

most sensitive monocot, based on the reviewer’s results, was onion based on height with NOAEC and EC25

values of <0.044 lb ai/A and 0.146 lb ai/A, respectively; the most sensitive dicot was soybean based on height 

with NOAEC and EC25 values of <0.0044 and 0.0194 lb ai/A, respectively. 

The in-life portion of this study was initiated on April 4, 2014 to November 4, 2014. 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 35 of 40 

F. CONCLUSIONS: 

This toxicity study is classified as supplemental for the herein labeled “Test 1”-21-day Study. The study was 

downgraded because the study authors failed to obtain NOAECs for the most sensitive endpoints for Carrot, 

Cucumber, and Onion, also the IC25 for onion dry weight (most sensitive endpoint) was below the lowest tested 

concentration. The concurrent study labeled here as Test 2 and Test 2a is classified as supplemental as well, as 

the study design did not allow for dry weight endpoints at the 21-day period, did not provide survival at 21-

days, and the 42-day endpoints failed to determine a NOAEC for soybean dry weight (most sensitive endpoint) 

and the IC25 was below the lowest tested concentration. Lastly, the most sensitive endpoint for carrot, 

cucumber, oat and ryegrass in the 42-day study was survival. The study is designed to capture sub-lethal 

effects, therefore, survival is not expected to be the most sensitive endpoint 

Test 1, 21 days 

The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with NOAEC and 

EC25 values of <0.044 lb ai/A and 0.0379 lb ai/A, respectively; the most sensitive dicot was cucumber based on 

dry weight with NOAEC and EC25 values of <0.0099 and 0.0145 lb ai/A, respectively. 

Most sensitive monocot and EC25/IC25: Onion (dry weight, 0.0379 lb ai/A). 

Most sensitive dicot and EC25/IC25: Cucumber (dry weight, 0.0145 lb ai/A). 

Test 2, 42 days 

The most sensitive monocot, based on the reviewer’s results, was onion based on dry weight with NOAEC and 

EC25 values of 0.092 lb ai/A and 0.0996 lb ai/A, respectively; the most sensitive dicot was soybean based on dry 

weight with NOAEC and EC25 values of <0.0044 and 0.00397 lb ai/A, respectively. 

Most sensitive monocot and EC25/IC25: Onion (dry weight, 0.0996 lb ai/A). 

Most sensitive dicot and EC25/IC25: Soybean (dry weight, 0.00397 lb ai/A). 

Test 2a, 21 days of 42 days 

The most sensitive monocot, based on the reviewer’s results, was onion based on height with NOAEC and EC25

values of <0.044 lb ai/A and 0.146 lb ai/A, respectively; the most sensitive dicot was soybean based on height 

with NOAEC and EC25 values of <0.0044 and 0.0194 lb ai/A, respectively. 

Most sensitive monocot and EC25/IC25: Onion (height, 0.146 lb ai/A). 

Most sensitive dicot and EC25/IC25: Soybean (height, 0.0194 lb ai/A). 

 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 36 of 40 

Study author Growth Rate Results: 

The study author analyzed and reported growth rate endpoint results for shoot length and dry weight. Results are for 

Test 1, 21 day study and Test 2, 21-42 days. For the Test 2, 21-42 days, the study author determined dry weight 

growth rate using the dry weights at the end of the 21 day study relative to the dry weights at the end of the 42 day 

study. All results using nominal concentration are in g ai/ha. 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 37 of 40 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 38 of 40 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 39 of 40 
Data Evaluation Record on the Acute Toxicity of Atrazine to Terrestrial Vascular Plants: 

Vegetative Vigor

PMRA Submission Number {..............} EPA MRID Number 49639101

Page 40 of 40 

III. REFERENCES: 

1. Ives, Michael, 2013. CETIS, Comprehensive Environmental Toxicity Information SystemTM. User's Guide. 

Tidepool Scientific Software, McKinleyville, California. 

2. Chetram, R.S., 1989. Tier 2 Vegetative Vigor Nontarget Phytotoxicity Test. Pan-Agricultural Laboratory, 

Inc. Madera, California, Final report date, August 23,1989. 233 pp. 

3. OECD, 1998. OECD Series on Principles of Good Laboratory Practice and Compliance Monitoring. 

Number 1. OECD Principles on Good Laboratory Practice (as revised in 1997). Environment Directorate 

Chemicals Group and Management Committee. ENV/MC/CHEM(98)17. OECD Paris, France. 41pp. 

4. OECD, 2006. OECD Guidelines for the Testing of Chemicals. Terrestrial Plant Test: Vegetative Vigor 

Test. OECD Guideline 227, adopted 19 July 2006. 

5. U.S. EPA, 1982. Pesticide Assessment Guidelines, Subdivision J, Hazard Evaluation: Nontarget Plants. 

PB83-153940, U. S. Environmental Protection Agency, Washington, DC. 

6. U.S. EPA, 1986. Hazard Evaluation Division. Standard Evaluation Procedure. Non-Target Plants: Seed 

Germination/Seedling EmergenceA'^egetative Vigor. EPA 540/9-86-132. U.S. EPA Washington, D.C. 

7. U.S. EPA, 1989. Federal Insecticide, Fungicide and Rodenticide Act (FIFRA); Good Laboratory Practice 

Standards; Final Rule (40 CFR, Part 160). Federal Register, 48 (230); 34052-34074. 

8. U.S. EPA, 1994. Pesticide Reregistration Rejection Rate Analysis: Ecological Effects. EPA 738-R-94-035, 

U.S. Environmental Protection Agency, Washington, D.C. 

9. U.S. EPA, 2012. Office of Chemical Safety and Pollution Prevention. Ecological Effects Test Guideline, 

OCSPP 850.4150. Vegetative Vigor. EPA 712-C-12-011. January 2012. U.S. Environmental Protection 

Agency, Washington, D.C.