2

Data Gaps

The available environmental fate and transport data set is considered incomplete and inadequate 

for the purposes of risk assessment. The data gaps are listed below. For each data gap, in absence 

of additional data, an assumption can be made for the purposes of risk assessment. These 

assumptions are identified in each bullet for fate studies, and consistent with other assessments, 

risk is presumed in the absence of ecological effects data.

• Aqueous Photodegradation (835.2240):

•

Although there are no acceptable studies, the 

Agency does not anticipate recommending a new study be conducted as a new study 

would not be expected to yield significantly different results.

Aerobic Soil Metabolism (835.4100)

•

. The Agency currently has data for only one soil in 

the submitted study. In absence of additional data, the Agency will multiply the single 

degradation half-life by three for the purposes of risk assessment to account for the 

potential variability in degradation rates between different soil types. The submission of 

studies on additional soil types would reduce the uncertainty in the degradation of 

bromacil in aerobic systems. The acceptable study is in a clay loam soil, thus the 

submission of an a study in a soil with higher organic matter may result in less 

conservative metabolism input for risk assessment.

Anaerobic Soil metabolism (835.4200)

•

. Currently, there are no available data. In lieu of 

acceptable data, bromacil is assumed to be stable to metabolism in soil in oxygen-limited

environments.

Aerobic Aquatic Metabolism (835.4300)

•

. Data requirement was previously waived due to 

modifications to the label for bromacil that intended to avoid use sites with high potential 

to result in aquatic exposure (DP 182792). 40 CFR part 158 Subpart N §158.1300 (July, 

2010) requires the submission of aquatic metabolism data for all pesticides with use 

patterns for terrestrial food and nonfood applications. In lieu of this data, modeling for 

risk assessment will assume 2x aerobic soil metabolism input (resulting in a 6x factor).

Additional data would reduce the considerable uncertainty with using the assumed 

modeling input. Additionally, the submission of acceptable soil metabolism data would 

reduce the uncertainty factor by 3x (in lieu of additional aerobic aquatic metabolism data, 

modeling assumes 2x the aerobic soil metabolism input).

Anaerobic Aquatic Metabolism (835.4400).

•

Currently there are no acceptable data for 

anaerobic aquatic metabolism. This study is necessary to understand the degradation of 

bromacil in oxygen-limited environments. In lieu of additional acceptable data, stability 

is assumed.

Adsorption/Desorption, Batch Equilibrium (835.1230).

•

Submitted studies only include 

soil column leaching data. Batch equilibrium data are needed to determine the sorption 

coefficients for bromacil, the bromacil acid should be used for this study as the salt 

dissociates to the acid under environmental conditions. In absence of these data

experimental organic carbon partitioning coefficients will be used from open literature 

sources (e.g., Gersch, 1984 and Corwin and Farmer, 1984). Additional data is unlikely to 

increase the conservatism of the assumed sorption coefficient for bromacil.

Terrestrial Field Dissipation (835.6100). The original study conducted at two bare-ground 

sites was classified acceptable. It was noted in the review that to fulfill the guideline 
3

additional studies are required on different soils that capture the use areas for bromacil 

(e.g., highly permeable citrus production areas of Florida). Based on open literature data 

and monitoring data that confirms that bromacil leaches through the soil profile and 

contaminates groundwater, the Agency does not anticipate needing additional data on the 

field dissipation of bromacil.

The available effects dataset is considered incomplete for the purposes of risk assessment. The 

following data gaps exist:

• 850.1350. No data have been received to characterize the chronic toxicity of bromacil to 

the estuarine invertebrate Americamysis bahia. In acute testing, estuarine invertebrates 

(i.e., A. bahia) were found to be more sensitive to bromacil than freshwater invertebrates

(Daphnia sp.). Alternatively, a NOAEC will be estimated using acute-to-chronic ratio 

for Daphnia magna of 14.8 (acute =121; chronic=8.2; 121/8.2=14.8). This would result 

in a mysid NOAEC of 7.7 ppm.

• 850.2100. A definitive acute oral LD50

• 850.2200. A sub-acute (dietary) study technical bromacil to birds has not been received. 

Alternatively, data from a study involving dietary exposures of birds to a formulated 

product containing bromacil will be used to assess avian dietary risk.

has not been established for an avian species. In 

order to gain a better understanding of how the EECs for the maximum bromacil

application rate relate to the toxicity data currently available for birds, the T-REX model

is used to calculate a ratio of the EEC and toxicity endpoint using the conservative 

assumption that the highest value tested represents the toxicity endpoint. In this exercise, 

some of the acute ratios calculated are > 1. Because the highest dose tested is below the 

highest predicted exposure level, the specific risk to birds from the use of bromacil is 

unknown. Therefore, in order to complete the risk assessment, additional data are 

needed. In the absence of such data, risks to both listed and non-listed bird species will 

be assumed in the risk assessment conducted for Registration Review.

• 850.4100 and 850.4150. Tier II terrestrial plant studies (seedling emergence and

vegetative vigor) conducted using a typical end-use product (TEP) are necessary for risk 

assessment. 

Additional detail on the current data gaps for environmental fate and effects for bromacil is 

provided in Section 8.
4

Problem Formulation for the Ecological Risk, 

Endangered Species, and Drinking Water Exposure 

Assessments in Support of the Registration Review of 

Bromacil and Bromacil Lithium Salt

CAS Registry Numbers: 314-40-9 and 53404-19-6

PC Codes: 012301 and 012302

Prepared by:

Nathan Miller, Biologist U.S. Environmental Protection Agency

Reuben Baris, Environmental Scientist Office of Pesticide Programs

 Environmental Fate and Effects Division

Reviewed by: Environmental Risk Branch 6

William Eckel, Acting Branch Chief 1200 Pennsylvania Ave., NW

 Mail Code 7507P

 Washington, DC 20460

May 22, 2012
5

Table of Contents

1. PURPOSE ...............................................................................................................................................................7

2. PROBLEM FORMULATION ..............................................................................................................................7

2.1. NATURE OF REGULATORY ACTION .................................................................................................................7

2.2. PREVIOUS ASSESSMENTS..................................................................................................................................7

2.2.1. Ecological Risk Assessments.......................................................................................................7

2.2.2. Drinking Water Exposure Assessment ........................................................................................8

3. STRESSOR SOURCE AND DISTRIBUTION....................................................................................................8

3.1. MECHANISM OF ACTION ..................................................................................................................................9

3.2. OVERVIEW OF PESTICIDE USE AND USAGE.....................................................................................................9

3.3. ENVIRONMENTAL FATE AND TRANSPORT.....................................................................................................14

3.3.1 Environmental Fate Assessment............................................................................................14

3.3.2 Environmental Transport Assessment ...................................................................................18

4. RECEPTORS........................................................................................................................................................20

4.1. EFFECTS TO AQUATIC ORGANISMS ...............................................................................................................20

4.1.1. Toxicity to freshwater fish..........................................................................................................21

4.1.2. Toxicity to freshwater invertebrates ..........................................................................................21

4.1.3. Toxicity to aquatic plants...........................................................................................................22

4.2. EFFECTS TO TERRESTRIAL ORGANISMS .......................................................................................................23

4.2.1. Toxicity to birds.........................................................................................................................24

4.2.2. Toxicity to mammals..................................................................................................................24

4.2.3. Toxicity to terrestrial insects .....................................................................................................25

4.2.4. Toxicity to terrestrial plants ......................................................................................................25

4.3. INCIDENT DATABASE REVIEW .......................................................................................................................27

4.4. ECOSYSTEMS POTENTIALLY AT RISK............................................................................................................27

5. ASSESSMENT ENDPOINTS..............................................................................................................................28

6. CONCEPTUAL MODEL................................................................................................................................28

6.1. RISK HYPOTHESIS ..........................................................................................................................................28

6.2. CONCEPTUAL DIAGRAM.................................................................................................................................29

7. ANALYSIS PLAN ................................................................................................................................................31

7.1. STRESSORS OF CONCERN ...............................................................................................................................32

7.2. MEASURES OF EXPOSURE ..............................................................................................................................32

7.3. MEASURES OF EFFECT ...................................................................................................................................34

7.4. INTEGRATION OF EXPOSURE AND EFFECTS ..................................................................................................35

7.5. DETERMINISTIC AND PROBABILISTIC ASSESSMENT METHODS....................................................................35

7.6. ENDOCRINE DISRUPTOR SCREENING PROGRAM...........................................................................................35

7.7. ENDANGERED SPECIES ASSESSMENT.............................................................................................................36

7.8. DRINKING WATER ASSESSMENT....................................................................................................................37

7.9. ENVIRONMENTAL MONITORING DATA .........................................................................................................37

7.10. CLEAN WATER ACT .....................................................................................................................................40

8. DATA GAPS AND UNCERTAINTIES .........................................................................................................41

8.1. ENVIRONMENTAL FATE .................................................................................................................................41

8.2. ECOLOGICAL EFFECTS...................................................................................................................................43

8.3. USAGE SPECIFIC UNCERTAINTIES ..................................................................................................................47

9. REFERENCES ......................................................................................................................................................48

APPENDIX A. ECOLOGICAL EFFECTS DATA SUMMARIES......................................................................50
6

APPENDIX B. FATE AND ECOLOGICAL EFFECTS BIBLIOGRAPHIES...................................................57

APPENDIX C. BROMACIL ECOLOGICAL INCIDENT SUMMARIES REPORTED IN THE EIIS 

DATABASE ...............................................................................................................................................................66
7

1. Purpose

The main purpose of this problem formulation is to provide the status of the environmental fate 

and ecological effects of bromacil and its lithium salt, considering its currently registered uses. 

Bromacil is a non-selective, broad spectrum herbicide of the uracil class. Registered nationally, 

agricultural uses of bromacil are limited to weed control in citrus orchards and pineapple fields, 

while non-agricultural uses of bromacil and its lithium salt are less geographically restricted, 

approved for weed and brush control for right-of-ways, railroads, and industrial yards among 

other sites. Bromacil can be applied as a soil band, soil broadcast, basal spray, or directed spray 

all of which will be considered during risk assessment. This document will provide a plan for 

analyzing data relevant to bromacil and for conducting ecological risk, federally-listed threatened 

and endangered species (hereafter referred to as “listed”), and drinking water exposure 

assessments for its registered uses. Additionally, this problem formulation is intended to identify 

data gaps, uncertainties, and potential assumptions used to address those uncertainties relative to 

characterizing the ecological risk associated with the registered uses of bromacil.

2. Problem Formulation

2.1. Nature of Regulatory Action

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), all pesticides distributed 

or sold in the United States generally must be registered by the Environmental Protection 

Agency (EPA). In determining whether a pesticide can be registered in the United States, EPA 

evaluates its safety to non-target species based on a wide range of environmental and health 

effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act, and the 

Agency was mandated to implement a new program for the periodic review of pesticides, i.e., 

Registration Review (http://www.epa.gov/oppsrrd1/registration_review/). The Registration 

Review program is intended to ensure that, as the ability to assess risk evolves and as policies 

and practices change, all registered pesticides continue to meet the statutory standard of no 

unreasonable adverse effects to human health and the environment. Changes in science, public 

policy, and pesticide use practices will occur over time. Through the new Registration Review 

program, the Agency periodically reevaluates pesticides to make sure that as change occurs, 

products in the marketplace can be used safely.

As part of the implementation of the Registration Review program pursuant to Section 3(g) of 

the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its 

evaluation of bromacil to determine whether it continues to meet the FIFRA standard for 

registration. This problem formulation for the ecological risk, listed species, and drinking water 

assessment chapter in support of Registration Review will be posted in the initial docket that will 

open the public phase of the review process.

2.2. Previous Assessments

2.2.1. Ecological Risk Assessments

Bromacil was first registered in the United States in 1961. EPA issued a Registration Standard 

for bromacil in September 1982 (PB87-110276). In 1996, the Agency completed a Reregistration 
8

Eligibility Decision (RED) for bromacil and its lithium salt (USEPA 1996). At the time of the 

RED, application rates were considerably higher than are presently registered, and registered 

uses included direct application to water. As a result, the RED identified potential acute toxicity 

risks to mammals, listed birds, listed freshwater fish and invertebrates, and terrestrial and aquatic 

plants, with potential chronic risk to mammals. The chronic toxicity dataset was largely 

deficient at the time of the RED, but because of the compound’s persistence in soil and water and 

the likelihood of repeat applications, the potential for chronic exposure was presumed to be high. 

Mitigation measures were required in the RED; specifically application rate reductions and 

restrictions on aquatic use that would reduce risk to freshwater fish and invertebrates. Consistent 

with what was done for the environmental fate and ecological risk assessment in support of the 

RED, only parent bromacil and its lithium salt are included in this assessment. 

In 2007, a litigation-related California red-legged frog (CRLF) effects determination was 

completed for bromacil. The CRLF assessment, which considered a maximum application rate 

of approximately half of the rate assessed in the RED, identified risk to aquatic nonvascular 

plants and small terrestrial mammals. The assessment resulted in a determination that the use of 

pesticide products containing bromacil and its lithium salt may affect, and is likely to adversely 

affect (LAA) the CRLF.

2.2.2. Drinking Water Exposure Assessment

No formal drinking water assessment has been completed for bromacil. However, in the RED 

drinking water exposure was assumed to be equal to the concentration of bromacil reported in 

submitted monitoring data (i.e., 100 ppb). This approach was used because extensive data exists 

as evidence that bromacil leaches to groundwater as a result of normal agricultural use. A 

calculation of exposure to bromacil in drinking water sources was completed. The Agency 

determined that an adult drinking 2 liters of water per day over a lifetime containing 100 ppb of 

bromacil reaches < 4% of the reference dose (RfD), and a 10 kg child drinking 1 liter of water 

containing 100 ppb of bromacil reaches 10% of the RfD. Furthermore, as the infant's/child's 

body weight increases with age, the percent of the RfD for consumption of bromacilcontaminated water decreases.

3. Stressor Source and Distribution

Bromacil is applied as a soil broadcast, soil banded, basal spray, or directed spray to control 

weeds in citrus orchards and pineapple fields. Bromacil and bromacil lithium are also registered 

for use on non-cropland areas, including (but not limited to) airports, parking lots, industrial 

areas, right-of-ways (for railroads, highways, pipeline and utilities), storage areas, lumberyards, 

tank farms, under asphalt and concrete pavement and fence rows. These chemicals can also be 

used in uncultivated portions of agricultural areas, including farmyards, fuel storage areas, fence 

rows and barrier strips. Aerial applications of bromacil are also registered on a national label.

This assessment considers registrations of bromacil, as well as its salt, bromacil lithium, which in 

the environment rapidly dissociates to the anion bromacil acid in water (pKa = 9.1). Bromacil 

and bromacil lithium are currently registered for use as herbicides, however since the salt rapidly 

dissociates to the acid in the environment this assessment is based on the acid bromacil.
9

3.1. Mechanism of Action

Bromacil is a uracil herbicide that interferes with plant photosynthesis by inhibiting the Hill 

reaction. The herbicidal activity of the compound results from its ability to block O2 release

during the photosynthetic sequence, causing a build-up of phytotoxic free radical molecules

(Hoffman 1971).

3.2. Overview of Pesticide Use and Usage

Bromacil, a non-selective broad spectrum herbicide, along with its lithium salt, are used for 

control of annual and perennial broadleaf and grass weeds in agricultural and non-agricultural 

lands. In agriculture, bromacil (not bromacil lithium) is applied as a soil treatment on citrus and 

as a post-harvest application on pineapples. There are also labeled pre-emergence and post-plant 

uses on pineapple fields. 

Bromacil is formulated as a wettable powder (WP), water dispersible granules (WDG), 

pressurized liquid, pressurized gas, as pellets and tablets, and in soluble and emulsifiable 

concentrates (SC and EC). The lithium salt of bromacil is exclusively formulated as a liquid. 

According to the Biological and Economic Analysis Division’s (BEAD) Usage Analysis Memo 

(USEPA 2011), roughly 370,000 lbs of bromacil is applied annually for the agricultural uses.

Oranges maintain the highest percent of total bromacil use at 86%, followed by grapefruit (10%),

and lemons (4%). Note that BEAD does not have data on pesticide use on pineapple. 

Most agricultural usage (in terms of pounds a.i.) occurs in Florida (74%) and California (21%)

(USEPA 2011). Based on information provided by BEAD, non-agricultural uses collectively 

comprise a small share of the total usage of bromacil, but total non-agricultural usage could not 

be quantified.

There are a total of 45 current and active labels and one pending product for bromacil at this 

time, and eight current and active labels for the bromacil lithium salt. Any new uses registered 

prior to completion of the ecological risk assessment in support of Registration Review will be 

assessed. 

Tables 3.1 and 3.2 present the uses and corresponding application rates (single and maximum), 

and the methods of application that will be considered in the Registration Review assessment. 

Where seasonal/annual application rates or reapplication intervals are not stated, conservative 

assumptions will be made for risk assessment, unless modifications to the label are made that 

would restrict the number of applications and the interval between applications. For example, 

EFED may assume a 3 day retreatment interval for foliar applications at the max labeled rate (the 

interval may be longer or shorter based on the activity of the compound). 
10

Table 3.1. Summary of use Sites and Application Rates for Bromacil.

Site Use Group AI%

Formulation

Maximum

Application

Rate

(lbs a.i./A)

Seasonal 

Max

Rate/Year

(lbs 

a.i./A/yr)

Application 

Method

Application 

Timing

PINEAPPLE TERRESTRIAL 

FOOD 80 WP 4.8 8 Broadcast. Postplant

PINEAPPLE TERRESTRIAL 

FOOD + FEED 80 WP 3.2 3.2

Soil 

broadcast Postharvest

PINEAPPLE TERRESTRIAL 

FOOD + FEED 80 WP 4.8 8

Soil 

broadcast Preemergence

CITRUS TERRESTRIAL 

FOOD + FEED 40 DF 3.2 6.4 Soil band When needed

80 WP 6.4 6.4

Soil 

broadcast 

Early summer, 

Winter

COMMERCIAL/INSTITUTIONAL/INDUSTRIAL 

PREMISES/EQUIPMENT 

(OUTDOOR)

TERRESTRIAL 

NON-FOOD 0.61 RTU 8.9 8.9 Spray When needed

FENCEROWS/

HEDGEROWS

TERRESTRIAL 

NON-FOOD 1 P/T 10 NS

Spot 

treatment. When needed

INDUSTRIAL / 

CONSTRUCTION AREAS 

(OUTDOOR)

TERRESTRIAL 

NON-FOOD 1.52 EC 12 NS Spray When needed

80 WP

.003125 lb / 

in of stem dia 12 

Basal spray 

treatment. Spring, Summer

NONAGRICULTURAL 

OUTDOOR 

BUILDINGS/STRUCTURES

TERRESTRIAL 

NON-FOOD 0.61 RTU 9 9 Spray When needed

NONAGRICULTURAL 

RIGHTS-OFWAY/FENCEROWS/HEDGE

ROWS

TERRESTRIAL 

NON-FOOD

40 DF 12 12

Soil band/ 

broadcast 

treatment When needed

80 WP

.003125 lb / 

in of stem dia 12 

Basal spray 

treatment. Spring, Summer

NONAGRICULTURAL 

UNCULTIVATED 

AREAS/SOILS

TERRESTRIAL 

NON-FOOD 1.52 EC 12 12 Spray When needed

80 WP

.003125 lb / 

in of stem dia 12 

Basal spray 

treatment. Spring, Summer

PAVED AREAS 

(ROADS/SIDEWALKS)

TERRESTRIAL 

NON-FOOD 80 WP 12 12

Soil 

treatment. Preconstruction

AGRICULTURAL 

UNCULTIVATED AREAS

TERRESTRIAL 

NON-FOOD 80 WP 12 12 

Soil 

treatment When needed

80 WP

.003125 lb / 

in of stem dia 12

Basal spray 

treatment. Spring, Summer

AIRPORTS/LANDING 

FIELDS

TERRESTRIAL 

NON-FOOD 2 G 8 12 Broadcast When needed

Formulation abbreviations: WP= wettable powder; G= granular; RTU=ready to use, DF= dry 

flowable; EC= emulsifiable concentrate; P/T= pelleted/tableted
11

Table 3.2. Summary of Terrestrial Non-food use Sites and Application Rates for Bromacil

Lithium Salt.

Site AI%

Formulation

A.I. Max 

App Rate

(lbs 

a.i./A)

A.I. Conv 

Seasonal 

Max 

Dose/Year

(lbs a.i./A)

Application 

Method

Application 

Timing

AGRICULTURAL RIGHTS-OFWAY/FENCEROWS/HEDGEROWS 21.9 L.003 lb / 

in stem 

dia

12.4 Basal spray 

treatment

Summer, Late 

winter.

21.9 L 12.4 12.4 Spray, 

Broadcast

Summer, Late 

winter.

AGRICULTURAL 

UNCULTIVATED AREAS 21.9 L

.003 lb / 

in stem 

dia

12.4 Basal spray 

treatment

Summer, Late 

winter.

21.9 L 12.4 12.4 Broadcast, 

Spray

Summer, Late 

winter.

INDUSTRIAL / CONSTRUCTION 

AREAS (OUTDOOR)

7.5 L 12 12 Broadcast When needed.

2.5 RTU

.00657031

lb / in 

trunk

12 Basal spray 

treatment When needed.

2.5 RTU 12 12 Broadcast When needed.

21.9 L

.00268902

lb / in 

stem dia

12.4 Basal spray 

treatment

Summer, Late 

winter.

21.9 L 12.4 12.4 Spray Summer, Late 

winter.

NONAGRICULTURAL RIGHTSOFWAY/FENCEROWS/HEDGEROWS

2.5 RTU

.00657031

lb / in 

trunk

12 Basal spray 

treatment When needed.

2.5 RTU 12 12 Broadcast When needed.

21.9 L

.00272778

lb / in 

stem dia

12.4 Basal spray 

treatment When needed.

21.9 L 24.78204 

lb / a NS Pre-paving treatment When needed.

21.9 L 12.4 12.4 Broadcast Summer, Late 

winter.

NONAGRICULTURAL 

UNCULTIVATED AREAS/SOILS 2.5 RTU

.00657031

lb / in 

trunk

12 Basal spray 

treatment When needed.

2.5 RTU 12 12 Broadcast When needed.

21.9 L

.00272778

lb / in of 

stem dia

12.4 Basal spray 

treatment When needed.

21.9 L 12.4 12.4 Broadcast Summer, Late 

winter

SEWAGE DISPOSAL AREAS 21.9 L 12.4 12.4 Broadcast, 

Spray When needed

Formulation abbreviations: L= liquid; RTU= ready to use
12

Table 3.3 contains estimates for the annual average pounds of bromacil applied on a given crop 

based on data obtained from the USDA’s National Agricultural Statistics Service (2003-2009)

1,2

, 

and private market research data (2003-2010)

3

. Additional registered uses may exist but are not 

included because the available surveys do not report usage (e.g., small acreage crops). Lack of 

reported usage data for the pesticide on a crop does not imply zero usage. In instances where 

usage on a site was noted but not quantified, the site would not be reported. Table 3.1 does not 

include non-agricultural use sites (e.g., airports, right-of-ways, stockyards, etc.). Some sites 

show some use, even though they are not on the label. This usage could be due to various 

factors, including, but not limited to Special Local Need (SLN) Exemptions, existing stocks of 

the chemical, and data collection errors. 

Table 3.3. Screening-Level Estimates of Agricultural Uses of Bromacil, Sorted 

Alphabetically

Percent Crop Treated

Crop Amount Active 

Ingredient (lb) Average Maximum

1 Fallow 1,000 <1 <2.5

2 Grapefruit 55,000 25 35

3 Lemons 10,000 10 15

4 Oranges 10,000 15 25

All numbers rounded.

<500 Less than 500 pounds of active ingredient

<2.5 Less than 2.5 percent of crop treated

<1 Less than 1 percent of crop treated

N/C Only Lbs. A.I. available

SLUA (screening-level usage analysis) data sources include: 

USDA-NASS (United States Department of Agriculture's National Agricultural Statistics Service) 

Private Pesticide Market Research

California DPR (Department of Pesticide Regulation)

 1 USDA, 2006-2010. NASS Crop Reporting Districts. Online: 

http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass

2 USDA, 2007. Census of Agriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp 3 Proprietary Data. 2006-2010
13

Table 3.4 includes data for bromacil applications in the state of California between 2007 and 

2010. Total bromacil use on oranges and tangerines has increased since 2007.

Table 3.4. Bromacil (012301) CA DPR Usage Data – Amount of Bromacil Used in 

California from 2007 to 2010 

Commodity 2007 Pounds 

Applied

2008 Pounds 

Applied

2009 

Pounds 

Applied

2010 

Pounds 

Applied

ALMOND 153

CITRUS FRUITS (ALL OR UNSPEC) 271 324 37 39

COMMERCIAL, INSTITUTIONAL OR 

INDUSTRIAL AREAS 69 4

GRAPEFRUIT 1940 1326 2612 1005

LANDSCAPE MAINTENANCE 2536 1898 2458 3948

LEMON 3108 2298 1855 2055

LETTUCE, LEAF (ALL OR UNSPEC) 27

LIME 43

N-OUTDR CONTAINER/FLD GRWN 

PLANTS 8 10

ORANGE 18039 17597 19286 22091

POMELO (SHADDOCK) (CITRUS 

GRANDIS) 16 106

RANGELAND (ALL OR UNSPEC) 6 8

RIGHTS OF WAY 56842 40933 20311 33779

SUGARBEET, GENERAL 2

SOIL APPLICATION, PREPLANTOUTDOOR 12

TANGELO 1013 961 1303 1029

TANGERINE 344 2462 3166 3524

UNCULTIVATED NON-AG AREAS 455 232 448 131

WALNUT 72

Grand Total 84772 68070 51580 67770

Date Prepared: 2/9/12

Cal DPR Data: http://www.cdpr.ca.gov/docs/pur/purmain.htm

Empty cells indicate no available usage.

Figure 1 shows agricultural pesticide usage at the Crop Reporting District (CRD) level (map 

generated by the Biological and Economic Analysis Division of the Office of Pesticide 

Programs). CRDs are boundaries created by USDA NASS which are aggregates of counties 

(USDA 2010). Pesticide usage is displayed as average pounds (for the years 2006-2010) per 

1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. 

Farmland acreage was obtained from USDA (USDA 2007). Usage is based on private market 

surveys of pesticide use in agriculture that are proprietary data covering the years 2006-2010

(USEPA 2012). The survey data are limited to the states that represent the top 80-90% of 
14

acreage for the individual crops; therefore, use may be occurring in regions outside the scope of 

the survey. It is important to note that data for usage on pineapple are not included in Figure 1, 

which is a major use for bromacil.

Figure 1. Estimated Annual National Agricultural Bromacil Usage.

3.3. Environmental Fate and Transport

The environmental fate database for bromacil is incomplete; there are some gaps in the database. 

All of the data in the environmental fate and transport database is based on bromacil versus the 

salt, bromacil lithium, since under environmental conditions the salt rapidly dissociates to the 

anion bromacil. Therefore the fate and transport information presented in this section is based on 

the anion bromacil.

3.3.1 Environmental Fate Assessment

Bromacil is a persistent and mobile herbicide. The primary routes of dissipation appear to be 

photolysis in water under alkaline conditions (pH 9) and microbial degradation under anaerobic 
15

conditions. However, the photodegradates under alkaline conditions have not been defined, and 

the rate of degradation under anaerobic conditions has not been accurately determined.

Degradation - Abiotic

In laboratory studies, bromacil was stable to hydrolysis, photodegradation in water at pH 5 and 7, 

and photodegradation on soil. At pH 9, where an absorption spectrum shift occurs, bromacil

photodegraded fairly rapidly with a half-life of 4-7 days. However, the radiolabeled residues in 

the pH 9 test solution were not further characterized, so degradates were not identified or 

quantified. Although this study is supplemental the Agency does not anticipate the need for a 

new study.

Degradation – Biotic

Microbial degradation of bromacil in aerobic soil is slow, with a half-life of 275 days in a silty 

clay loam soil. Carbon dioxide was the major degradate, totaling 40.3% of the applied at 12 

months posttreatment. Data for only one soil have been submitted to the Agency; therefore there 

is considerable uncertainty about the variability in degradation in different soil types. OPPTS 

guideline number 835.4100 requires a single soil for metabolic pathway identification, and three 

additional soils for determination of degradation kinetics. When there is only one acceptable 

soil, it is Agency policy to multiply the single soil half-life by three in risk assessment to account 

for the potential variability that exists in the degradation rate for different soils.

Aerobic soil metabolites were a maximum of 1.6% of applied radioactivity. Five nonvolatile 

degradates were identified: 1) 5-bromo-6-methyluracil (Metabolite G) was a maximum of 3.4% 

of applied radioactivity at 304 days post-treatment; 2) 5-bromo-3-(alpha-hydroxymethylpropyl)-

6-methyluracil (Metabolite C) was a maximum of 1.5% of applied radioactivity at 154 and 184 

days; 3) 5-bromo-3-sec-butyl-6-hydroxymethyluracil (Metabolite A) was a maximum of 0.6% 

of applied radioactivity at 184 days post-treatment; 4) 5-bromo-3-(2-hydroxy-1-methylpropyl)-6-

methyluracil (Metabolite D) was a maximum of 0.8% of applied radioactivity at 304 days; and, 

5) 3-sec-butyl-6-methyluracil (Metabolite F) was a maximum of 0.7% of applied radioactivity at 

304 days.

The anaerobic aquatic metabolism study submitted to the Agency is unacceptable and cannot be 

upgraded. The study did not adequately characterize the degradation of bromacil under anaerobic 

conditions, which may be a major route of dissipation in subsoil. The sampling intervals were 

inadequate to accurately establish the half-life of the test substance (>50% degraded between two 

samplings). Between day 28 and day 93, the percent applied radioactivity identified as bromacil 

decreased from 78.1% to 1.3%. This study does provide information on the formation of a major 

degradate, Metabolite F, also detected in the aerobic soil metabolism study. Metabolite F was a 

maximum of 80.7% of the applied at day 304 post-treatment. This product is likely formed 

through reductive dehalogenation, a reaction favored under anaerobic conditions. A new 

anaerobic aquatic study with adequate sampling intervals to determine a half-life was 

recommended in the RED, but was not issued in the Generic Data Call-in (GDCI).
16

Bromacil may be expected to degrade more rapidly under anaerobic than aerobic conditions. In

an open-literature laboratory study, bromacil had an observed half-life of 144 to 198 days in 

Greenfield sandy loam soil under saturated (anaerobic) soil conditions (Wolf, 1974). However, 

there is no acceptable guideline study for aquatic metabolism (aerobic or anaerobic), nor 

anaerobic soil. Therefore in absence of these data, for risk assessment purposes, the following 

conservative assumptions will be made:

Aerobic aquatic metabolism: 2x the aerobic soil metabolism input 

 (275d x 3 x 2 = 1,650 days)

Anaerobic aquatic metabolism: “stable to microbial degradation” 

Anaerobic soil metabolism: “stable to microbial degradation”

Accumulation

Bromacil accumulates only slightly in fish and depurates rapidly. Maximum bioconcentration 

factors (BCF) were 4.6X for muscle, 6.8-8.3X for viscera, 2.1-2.2X for carcass, and 2.5-2.8X for 

whole fish. Depuration was rapid, with >96% of the accumulated [14C] residues eliminated from 

the fish tissues by day 3 of the depuration period.

Table 3.5 presents the chemical identities of bromacil and bromacil lithium. Table 3.6 presents 

the general physical and chemical properties, as well as the available environmental fate 

properties of bromacil.

Table 1.5. Chemical identities of bromacil and bromacil lithium.

PARAMETER Bromacil Bromacil lithium

PC code 012301 012302

CAS No. 314-40-9 53404-19-6

Chemical name 5-bromo-3-sec-butyl-6-methyluracil 5-bromo-3-sec-butyl-6-methyluracil, lithium 

salt

Chemical formula C9H13BrN2O2 C9H12BrN2O2Li+

Molecular weight 261.1 g/mol 267.1 g/mol

Table 3.6. General Chemical Properties and Environmental Fate Properties of Bromacil.

Parameter Value Reference (MRID #) 

/Comment

Physical/Chemical Parameters

Molecular mass 261.12 g/mol USEPA, 1996

Vapor pressure (20°C) 3.1 x 10-7 torr USEPA, 1996

Henry’s Law Constant 1.1 X 10-9 atm*m3

/mol USEPA, 1996

Water solubility (25°C) 815 mg/L in water USEPA, 1996

Octanol-water partition coefficient (LogKOW 2.11 ) Hansch & Leo, 1995

Dissociation Constant (pKa) 9.1 bromacil ionizes at pH 

9.1; USEPA, 1996 
17

Parameter Value Reference (MRID #) 

/Comment

Mobility

Freundlich adsorption partition coefficient,

Koc, L/kgoc

Baldwin Lake 

(1/n) Big Bear Lake

Castle Lake

Clear Lake

Delta Lake

Jenks Lake

Mockingbird Canyon

San Joaquin Marsh

Average

289.1 (0.984)

49.7 (0.860)

43.8 (0.930)

39.5 (0.917)

61.7 (0.905)

39.9 (0.891)

26.5 (0.951)

26.3 (0.900)

41.1 (0.917)

Corwin and Farmer (1987)

Column Leaching Soil Texture % of applied 

bromacil found in 

leachate of the four 

columns

MRID 40951512 (only 

column leaching data 

were available from 

submitted studies)

Sand total residues in 

leachate = 91.2-

99.6% of the applied;

bromacil in leachate 

= 89.0-94.1% of the 

applied

Sandy loam

Clay loam

Silt loam

Persistence in Water

Hydrolysis half-life (25°C, pH 5, 7, & 9) Stable MRID 40951505

Aqueous photolysis half-life (25°C) (t 1⁄2 days) pH 5: 356 

pH 7: 102 

pH 9: 7, 4.3

MRIDs 40951507, 

40951508

Absorption spectrum 

shift occurs in alkaline 

conditions (at pka of 

9.1).

Aerobic aquatic metabolism half-life No data No studies submitted.

Anaerobic aquatic metabolism half-life No data for degradation of bromacil in 

anaerobic conditions.

Submitted study 

unacceptable half-lives 

are unreliable.

Persistence in Soil

Soil Photolysis (t 1⁄2 days) 166 MRID 40951509

Aerobic soil metabolism half-life (25°C) (days) 275 MRID 40951510

Single soil (silty clay 

loam, Stine Farm Soil)

Anaerobic soil metabolism No data No acceptable studies 

submitted.

Field Dissipation

Terrestrial field dissipation half-life (DT50) 155 (silty clay loam soil in DE) †

124 (loam soil in CA)

MRID 41677101; 

dissipation from soil 

surface of bare ground 

plots

Aquatic Bioconcentration
18

Parameter Value Reference (MRID #) 

/Comment

Bioconcentration Factor (BCF) in fish 2.5-2.8X MRID 40951513

3.3.2 Environmental Transport Assessment

Laboratory mobility data, in addition to groundwater monitoring information, have clearly 

demonstrated that bromacil is mobile in soil. However, bromacil’s tendency to leach was not 

overwhelmingly apparent from the two field dissipation studies. The timing and amount of 

rainfall/irrigation in these studies is a possible explanation. The following section provides an 

overview of the environmental transport of bromacil.

Mobility

In column leaching studies, bromacil was mobile in columns of sand, sandy loam, clay loam, and 

silt loam soils. [14C]Residues in the leachates of all four soils totaled 91.2-99.6% of the applied

(bromacil comprised 89.0-94.1% of the applied).

Aged (30 days) bromacil residues were also mobile in a column of silt loam soil. [14

Batch equilibrium data were not submitted for bromacil. Additional data to determine the 

mobility of bromacil in the environment are needed to support an exposure assessment for 

bromacil. The added value of this data will provide the Agency with guideline compliant

sorption coefficients in multiple soils confirming the findings in open literature (Corwin and 

Farmer, 1984 and Gerstl, 1984) and QSAR estimates that bromacil is a leacher. In the CRLF 

effects determination assessment a K

C]Residues 

in the leachate totaled 87.3% of the applied radioactivity. Bromacil was the only compound 

identified in the leachate, comprising 82.8% of the applied radioactivity. 

oc value of 32 L/kgoc was used to model aquatic exposures,

which was obtained from the Soil Conservation Service Agricultural Research Station 

(SCS/ARS) database (USEPA, 2007). EPISuite v 4.1 provides an estimated Koc value of 66 

L/kgoc. The EPISuite value is twice the SCS value, but is still classified as mobile based on FAO 

Soil Mobility Classifications. This value is similar in magnitude to values reported in the open 

literature. Gerstl (1984) found an average Koc value of 23 L/kgoc from experimental values 

determined in 8 soils and 4 sediments. Corwin and Farmer (1984) reported adsorption in eight 

freshwater sediments, with Koc’s ranging from 26.3 to 289.1 L/kgoc (an average of 41.1 L/kgoc).

These values indicate that bromacil is mobile in soil, a conclusion which is consistent with the 

results observed in the column leaching studies. In absence of additional submitted data, the 

values reported in Corwin and Farmer (1984) and Gerstl (1984) will be formally reviewed and if 

found acceptable for use in risk assessment, the reported sorption values will be used for 

modeling purposes.

Field Dissipation

In the field, bromacil was persistent, but did not demonstrate the degree of mobility that was 

predicted based on the laboratory studies and the available groundwater monitoring data. One 

possible explanation for the limited mobility in the two sites could be the amount and timing of 
19

rainfall and irrigation. However, the average rainfall for the test period was about or above the 

30-year annual average of 43.36 inches for Wilmington, Delaware, so minimal irrigation was 

needed. The average rainfall at the second field site was below the 30-year annual average of 

9.84 inches for Fresno, California, so substantial irrigation was needed. Irrigation was based on 

common agricultural practice for the area. Bromacil (Hyvar® X Herbicide, 80% WP), applied at 

12 lb ai/A, dissipated with half-lives of 155 days from the upper 10 cm of a bare ground plot of 

silty clay loam soil located in Delaware, and 124 days from the upper 10 cm of a bare ground 

plot of loam soil located in California. Bromacil was detected at the Delaware and California 

sites in the upper 10 cm of the plots through 538 and 415 days post treatment, respectively. 

Transport

Potential transport mechanisms for bromacil include surface water runoff, spray drift, and 

secondary drift of volatilized or soil-bound residues leading to deposition onto nearby or more 

distant ecosystems. The magnitude of pesticide transport via secondary drift depends on the

pesticide’s ability to be mobilized into air and its eventual removal through wet and dry 

deposition of gases/particles and photochemical reactions in the atmosphere. Based on the vapor 

pressure and Henry’s Law constant of bromacil, volatilization from treated areas resulting in 

atmospheric transport and deposition represent unlikely transport pathways.

Extensive data exists as evidence that bromacil leaches to groundwater as a result of normal 

agricultural use. Less data are available to determine the impact of bromacil applications from 

use on rights-of-way or other non-agricultural uses. Data currently available to the EPA in a 

retrospective groundwater study, conducted prior to the RED, indicate that bromacil has been 

detected in groundwater in 5 states, with concentrations in many Florida wells exceeding 100 

ppb (DP 191409, 191677). Bromacil has been shown conclusively from groundwater monitoring 

data to leach to groundwater, diminishing the quality of the resource. In areas of the Central 

Ridge of Florida, such as DeSoto City, groundwater contaminated with bromacil had remained 

contaminated for several years. Based on this information, and the environmental fate and 

transport profile for bromacil, there is the potential for bromacil to contaminate groundwater 

resources. 

DuPont conducted a retrospective groundwater monitoring study in three citrus growing regions 

of Florida between 1987 and 1990. Bromacil was detected in groundwater at all three study sites 

(described in greater detail in Section 7.9). DuPont also conducted a prospective groundwater 

monitoring study in response to the Generic Data Call-in (GDCI) issued as part of the RED. It 

was designed to evaluate the potential for bromacil to leach to groundwater in Florida’s Central 

Ridge region required by both the USEPA and Florida Dept. of Agriculture and Consumer 

Services as part of a proposed bromacil management strategy. This study is currently under 

review by the Agency, however preliminary review of the results show that the concentrations 

detected in groundwater are lower than those reported prior to the implementation of the label 

mitigations. Additional groundwater monitoring data from state-level studies in Florida, Texas, 

and California detail bromacil contamination of groundwater resources. These data are 

discussed in greater detail in the RED and below in section 7.9.
20

4. Receptors

Consistent with the process described in the Overview Document (USEPA, 2004), the risk 

assessment for bromacil will rely on a surrogate species approach. Toxicological data generated 

from surrogate test species, which are intended to be representative of broad taxonomic groups, 

are used to extrapolate the potential effects on a variety of species (receptors) included under 

these taxonomic groupings.

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the 

available open literature are used to evaluate the potential direct and indirect effects of bromacil 

to aquatic and terrestrial receptors. This includes toxicity on the technical grade active 

ingredient, degradates, and when available, formulated products (e.g., “Six-Pack” studies). The 

open literature studies are identified through EPA’s ECOTOXicology (ECOTOX) database4

, 

which employs a literature search engine for locating chemical toxicity data for aquatic life, 

terrestrial plants, and wildlife. The evaluation of both sources of data may also provide insight 

into the direct and indirect effects of bromacil on biotic communities from loss of species that are 

sensitive to the chemical and from changes in structure and functional characteristics of the 

affected communities. A review of open literature data from ECOTOX on bromacil will be 

conducted prior to initiation of the risk assessment phase for possible quantitative and/or 

qualitative inclusion in this risk assessment. The Agency seeks comments from the public on 

more sensitive endpoints that may be used in risk assessment. 

A summary of the most sensitive submitted data representing non-target organisms exposed to 

bromacil in aquatic and terrestrial habitats is provided in Sections 4.1 and 4.2, respectively.

4.1. Effects to Aquatic Organisms

A summary of the aquatic toxicity data for bromacil (and the lithium salt of bromacil, where 

applicable) from registrant-submitted studies is provided in Table 4.1. The bibliography of all 

submitted ecotoxicity data for bromacil is provided in Appendix B, and study summaries are 

provided in Appendix A. Bromacil is classified as slightly toxic to freshwater fish and 

practically nontoxic to estuarine/marine fish on an acute exposure basis. The most sensitive 

acute toxicity endpoints (96-hr LC50 values) for freshwater and estuarine/marine fish are 36,000 

(rainbow trout; Oncorhynchus mykiss) and 162,000 μg/L (sheepshead minnow; Cyprinodon 

variegatus), respectively. Among freshwater and estuarine/marine invertebrates, the most 

sensitive acute toxicity endpoints (EC50 values) were 121,000 μg/L (water flea; D. Magna) and 

112,900 μg/L (mysid shrimp; Americamysis bahia), respectively.

On a chronic exposure basis, the most sensitive endpoints for freshwater fish and freshwater 

invertebrates are for rainbow trout (O. mykiss); NOAEC= 3,000 μg/L and water flea (Daphnia 

magna); NOAEC= 8,200 μg/L. No chronic data is available for estuarine/marine fish. Since 

there is no indication that estuarine/marine organisms are more sensitive than freshwater 

organisms, in the absence of additional data EFED will use the chronic freshwater fish data when 

 4 USEPA. 2011. ECOTOX Database http://cfpub.epa.gov/ecotox/
21

evaluating chronic risk to saltwater fish. No data are available to assess chronic toxicity to

estuarine/marine invertebrates.

Aquatic vascular and non vascular plants are extremely sensitive to bromacil. The 14-day EC50

for the vascular aquatic plant duckweed (Lemna gibba) is 45 μg/L, and the most sensitive nonvascular species is freshwater green algae Pseudokirchneriella subcapitata, with a 120-hr EC50

of 6.8 μg/L.

4.1.1. Toxicity to freshwater fish

Acute exposures

The available registrant-submitted study involving rainbow trout (O. mykiss) was a static, 96-h 

exposure, resulting in a LC50 of 36 mg/L (95% confidence interval: 30-40 mg/L). This LC50

value represents the most sensitive endpoint available for acute exposures of fish to bromacil. 

Sublethal effects observed in surviving fish exposed to 22.5 mg/L bromacil and higher included 

loss of equilibrium, swollen appearance and sinking to the bottom of test vessels. No effects 

were described at 16.9 mg/L (MRID 40951503). 

The registrant-submitted study involving bluegill sunfish (Lepomis macrochirus) was a static, 

96-h exposure, resulting in a LC50 of 127 mg a.i./L. Sublethal effects observed in surviving fish 

exposed to 95 mg/L bromacil and higher included loss of equilibrium. No effects were described 

at 71 mg/L (MRID 40951502).

Chronic exposures

Data are available from a registrant-submitted study where rainbow trout (O. mykiss) were 

exposed to bromacil for 90 days in a flow-though study. The NOAEC and LOAEC values for 

this study were 3.0 and 7.2 mg a.i./L, respectively, based on treatment-related effects to mean 

wet weight, which was the only measured endpoint that was affected. At the highest test 

concentration (7.2 mg a.i./L), measured wet weights of juvenile fish were 32.4% lower than 

controls. No treatment related effects on survival were observed in any of the treatment groups 

(maximum of 7.2 mg a.i./L). This study is scientifically sound, but is classified supplemental, 

due to excessive variation in measured concentrations of bromacil in the treatment levels (MRID 

44566101).

4.1.2. Toxicity to freshwater invertebrates

Acute exposures

The available registrant-submitted study involving waterflea (D. magna) was a static, 48-h 

exposure, resulting in an EC50 of 121 mg/L (95% confidence interval: 111-148 mg/L), based on 

immobility. Effects were observed at 111 and 148 mg/L (20% and 100% immobility, 

respectively, with no effects described at 83 mg/L (MRID 40951504). This EC50 value is used 

in this risk assessment for quantifying RQ values for acute exposures of aquatic invertebrates to 

bromacil.
22

Chronic exposures

Data are available from a registrant-submitted study where waterfleas (D. magna) were exposed 

to bromacil for 21 days. The NOAEC and LOAEC values for this study were 8.2 and 21 mg 

a.i./L, respectively, based on treatment-related effects to reproduction and growth. In the 21 mg 

a.i./L treatment level, adults did not produce offspring. Also, at that treatment level, adults had 

significantly reduced body lengths and dry weights in comparison to organisms in the negative 

control (13% and 45% decreases, respectively; MRID 44566401). 

4.1.3. Toxicity to aquatic plants

Bromacil is highly toxic to aquatic plants, with an EC50 for Selenastrum capricornatum of 6.8 

ppb. This is of particular concern in Florida, where because of high water tables, groundwater 

discharges into drainage canals, which ultimately drain into surface water bodies. In addition, 

bromacil has been found in groundwater at concentrations that exceed levels-of-concern for nontarget terrestrial plants, as determined by seedling-emergence studies. This could be a concern in 

areas where contaminated ground water is used for irrigation.

Unicellular plants

Registrant-submitted studies for algae and diatoms (unicellular plants) include EC50 values 

ranging from 6.8-69.9 μg a.i./L, based on decreased cell density. Reductions in biomass 

(determined from cell counts recorded via Coulter Counter) for Selenastrum capricornutum were 

observed at exposures to the lowest bromacil concentrations tested, i.e., 1.1 μg a.i./L. 

Vascular plants

Data are available from a registrant-submitted study where duckweed (L. gibba) was exposed to 

bromacil for 14 days. The NOAEC and EC50 values based on decrease in frond number were 17 

and 45 μg a.i./L, respectively. Effects to dry weight were also observed during this study (MRID 

46095401) albeit at higher concentrations.
23

Table 4.1. Summary of the Endpoints from Submitted Aquatic Toxicity Studies for 

Bromacil

Study Type Species Toxicity Value Toxicity 

Classification MRID & Status

Acute –

Freshwater Fish

850.1075

Rainbow trout 

(Oncorhynchus mykiss) 96-hr LC50: 36 ppm Slightly toxic 40951503

Acceptable

Acute –

Estuarine/Marine 

Fish

850.1075

Sheepshead minnow 

(Cyprinodon 

variegatus)

96-hr LC50: 162.8 ppm Practically 

nontoxic

41588702

Acceptable

Chronic –

Freshwater Fish

850.1400

Rainbow trout 

(Oncorhynchus mykiss)

NOAEC: 3.0 ppm

LOAEC: 7.2 ppm N/A 44566101

Supplemental

Chronic--

Saltwater Fish

850.1400

N/A N/A N/A Data Gap

Acute –

Estuarine/Marine 

Invertebrate

850.1035

Mysid shrimp 

(Americamysis bahia) 96-hr LC50

Practically 

nontoxic : 112.9 ppm 41588701

Acceptable

Acute –

Freshwater 

Invertebrate

850.1010

Water flea (Daphnia 

magna) 48-Hr EC50

Practically 

nontoxic 121 ppm 40951504

Acceptable

Chronic –

Freshwater 

Invertebrate

850.1300

Water flea (Daphnia 

magna)

NOAEC: 8.2 ppm

LOAEC: 21 ppm

(reproduction and 

growth)

N/A 44566401

Acceptable

Chronic –

Estuarine/Marine 

Invertebrate

850.1350

N/A N/A N/A Data Gap

Aquatic – Nonvascular Plants

850.5400

Green algae 

(Pseudokirchneriella 

subcapitata)

[Tier 2]

120-hour EC50 N/A : 0.0068 

ppm

42516401

Supplemental

Aquatic –

Vascular Plants

850.4400

Duckweed (Lemna 

gibba)

[Tier 2]

EC50

NOAEC: 0.017 ppm

: 0.045 ppm

(frond number and 

dryweight)

N/A 46095401

Acceptable

4.2. Effects to Terrestrial Organisms

Table 4.2 summarizes the terrestrial toxicity data for bromacil based on an evaluation of 

submitted studies. In general, bromacil is characterized as practically nontoxic toxic to birds on 

an acute oral exposure basis and practically nontoxic on a subacute dietary exposure basis. The 

acute oral endpoint for the northern bobwhite quail (Colinus virginianus) was > 2250 mg/kg, and 

subacute dietary LC50s for C. virginianus and mallard duck (Anas platyrhynchos) were > 10,000 

mg/kg-diet/day. C. virginianus and A. platyrhynchos were equally sensitive under the study 

design for chronic exposure (NOAEC=1550 mg/kg diet).
24

4.2.1. Toxicity to birds

Acute

Data are available from a registrant-submitted study, where bobwhite quail (Colinus virginianus) 

were given acute, oral doses of bromacil. No mortalities were observed during the 14-day study 

period, which resulted in a LD50 >2250 mg/kg (highest dose tested). Between days 0 and 3, 

reduced body weight gains in relation to the control were observed at the two highest test doses, 

resulting in a NOAEL of 810 mg/kg. At 1350 mg/kg, body weight gains in female birds were 

5.1% lower than controls. At 2250 mg/kg, body weight gains in female and male birds were 

decreased 4.7 and 5.4%, respectively, when compared to controls. By the end of the study, body 

weight gains of females and males were similar in all treatment groups, including controls 

(MRID 40951501). 

No data are available for sub-acute dietary exposures of birds to technical bromacil. In lieu of 

toxicity data for technical grade bromacil, available data from a study involving dietary-based 

exposures of birds to a formulated product (Hyvar® X Bromacil Weed Killer, 80% a.i.) of 

bromacil are used in this assessment. In this study, mallard ducks (Anas platyrhynchos) and 

bobwhite quail were exposed to a formulated product of bromacil (83.4% a.i.) through dietary 

exposures. The resulting 8-d LC50 values for both species exceeded the highest concentration 

tested, i.e., >10,000 mg/kg-diet/day (of bromacil). No mortalities were observed in exposures 

involving mallard ducks. Bobwhite quail mortalities were observed in exposures involving 

several different treatment levels; however, the mortalities were less than 50% of individuals in 

each treatment group. In the test, 6.8% mortality was observed in controls, 10% mortality was 

observed in the 464 and 4,640 mg/kg-diet/day treatment levels and 20% mortality was observed 

in the 2,150 and 10,000 mg/kg-diet/day treatment levels (MRID 00013295). This study is 

classified acceptable for a formulated product, but supplemental for use in risk assessment, since 

the test material was not technical bromacil as required by 40 CFR §158.630.

Chronic

Data are available from two registrant-submitted studies, where bobwhite quail and mallard 

ducks were given chronic (21-week) dietary exposures to bromacil. In the study involving 

Northern bobwhite quail, effects to hatchability, embryo viability, embryo survival and hatching 

survival were observed at 3100 mg/kg-diet/day, resulting in a NOAEC of 1550 mg a.i./kgdiet/day (MRID 44844801). In the study involving mallard ducks, significant effects were 

observed in egg shell thickness at the 3100 mg a.i./kg-diet/day treatment level. Significant 

effects to hatchability of mallards were observed at the 6200 mg a.i./kg-diet/day treatment level. 

The NOAEC for this study was also 1550 mg a.i./kg-diet/day (MRID 44844601).

4.2.2. Toxicity to mammals

Acute
25

Data are available from a registrant-submitted study, where laboratory rats (Rattus norvegicus) 

were given acute oral doses of technical grade bromacil. Mortalities were observed in animals 

dosed with 1000 and 2000 mg/kg, which resulted in an acute oral LD50 of 812 mg/kg for females 

and 1682 mg/kg for males. Sublethal effects that were observed included: hunched posture, 

ataxia, lethargy, decreased respiration, hemorrhagic lungs, and dark liver and kidneys (MRID 

44196209).

Chronic

Data are available from a 2-generation dietary exposure reproduction study in rats. The reported 

NOAEL was 250 mg/kg-diet/day, with a LOAEC of 2500 mg/kg-diet/day. Observed effects 

included decreased growth (body weight reductions) in parent and first and second generation 

offspring (MRID 41804601). 

4.2.3. Toxicity to terrestrial insects

Data are available on the acute toxicity of bromacil to honey bees (Apis mellifera). In an acute 

contact toxicity study, the LD50 was higher than the highest dose tested, i.e., >11 μg a.i./bee 

(MRID 00251374). In another study involving 96-h acute contact exposures of honeybees to a 

formulated product containing bromacil (Hyvar® X Bromacil Weed Killer, 80% a.i.), the LC50

was >193.38 μg/bee (MRID 00018842). At this level, 1.2% mortality was observed. 

Adjustment of this value for the % a.i. of the test substance results in an LD50 >155 μg a.i./bee. 

This toxicity value is converted to units of μg a.i./g (of bee) by multiplying by 1 bee/0.128 g 

thereby resulting in an LD50 >1209 μg a.i./g.

4.2.4. Toxicity to terrestrial plants

Toxicity data were submitted from seedling emergence and vegetative vigor studies involving 

separate exposures of wheat (monocot) and rape (dicot) to technical bromacil and technical 

bromacil lithium. This study was intended to create suitable data for comparison of the effects of 

bromacil and bromacil lithium on seedling emergence and vegetative vigor, using the most 

sensitive monocot and dicot species as determined by MRID 42491101.

In the seedling emergence tests involving bromacil and bromacil lithium, percent survival, dry 

weight and plant height were significantly affected in both wheat and rape. The percent

inhibition in seedling emergence in the treated species as compared to the control ranged from -

11 to 5% for bromacil and from -5 to 13% for bromacil lithium. The most sensitive endpoint for 

wheat and rape in the seedling emergence tests was dry weight. The following abnormalities 

were noted for bromacil: slight growth retardation, malformations, chlorosis and necrosis. The 

following abnormalities were noted for bromacil lithium: slight to moderate chlorosis, slight to 

severe growth retardation, slight unusual pigmentation and slight to severe burn or necrosis. 

NOAEC, EC25 and EC50 values for bromacil and bromacil lithium exposures indicate that the 

two chemicals are of similar toxicities to wheat and to rape (MRID 444883-07).

In the vegetative vigor tests, the plant dry weight and plant height were affected by exposures to

bromacil and bromacil lithium. The most sensitive endpoint for wheat and rape in the vegetative 
26

vigor tests was dry weight. The following abnormalities were noted in tests where plants were 

exposed to bromacil or bromacil lithium: chlorosis, necrosis and growth retardation. NOAEC, 

EC25 and EC50 values for bromacil and bromacil lithium exposures indicate that the two 

chemicals are of similar toxicities to wheat and to rape (MRID 44488307).

Table 4.2. Summary of the Endpoints from Submitted Terrestrial Toxicity Studies for 

Bromacil

Study Type Species Toxicity Value Toxicity Classification MRID & Status

Acute – Avian 

Oral

850.2100

Bobwhite Quail 

(Colinus virginianus) LD50: >2250 mg/kg-bw Practically nontoxic 40951501

Acceptable

Acute – Avian 

Dietary

850.2200

Mallard Duck

(Anas platyrhynchos),

Bobwhite Quail 

(Colinus virginianus)

8-day LC50: >10,000 ppm Practically nontoxic

00013295, 

00013296

Acceptable

Chronic – Avian 

Reproduction

850.2300

Mallard Duck

(Anas platyrhynchos),

Bobwhite Quail 

(Colinus virginianus)

NOAEC: 1550 ppm

LOAEC: 3100 ppm

(eggs set, embryo viability, 

hatchability, hatchling 

survival)

N/A

44844601, 

44844801

Acceptable

Acute –

Mammalian Oral

870.1100

Rattus norvegicus 

(laboratory rat) LD50 = 812 mg/kg Slightly toxic 44196209

Acceptable

Two-generation 

Mammalian 

Reproduction

870.4100

Rat (Rattus 

norvegicus)

NOAEC = 250 mg/kgdiet/day 

(bodyweight reductions)

LOAEC = 2500 mg/kgdiet/day 

N/A

41804601

Acceptable

Chronic 

Mammalian 

Reproduction 

(developmental)

870.4100

Rabbit

(Sylvilagus sp.)

NOAEL/LOAEL = 100/300 

mg/kg

(development)

N/A 40984801

Acute – Contact 

Toxicity

850.3020

Honey Bee

(Apis mellifera) LD50: 193 μg ai/bee Practically nontoxic 00009181

Supplemental

Terrestrial plant 

Seedling 

emergence-Tier 

II 850.4225

Monocot: 

Wheat

EC25 

NOAEC= 0.020 lbs ai/A

= 0.030 lbs ai/A N/A 44488307

Supplemental

Lithium salt:

EC25 

NOAEC= 0.020 lbs ai/A

= 0.034 lbs ai/A N/A 44488307

Supplemental

Dicot: 

Oilseed rape

EC25 

NOAEC= 0.0011 lbs ai/A*

= 0.0047 lbs ai/A N/A 44488307

Supplemental

Lithium salt:

EC25 

NOAEC= 0.006 lbs ai/A

= 0.010 lbs ai/A N/A 44488307

Supplemental

Terrestrial plant 

Vegetative 

vigor-Tier II

850.4250

Monocot: 

Wheat

EC25 

NOAEC= 0.020 lbs ai/A

= 0.042 lbs ai/A N/A 44488307

Supplemental

Lithium salt:

EC25 

NOAEC= 0.001 lbs ai/A

= 0.028 lbs ai/A N/A 44488307

Supplemental

Dicot:

Oilseed rape

EC25 

NOAEC= 0.006 lbs ai/A

= 0.0055 lbs ai/A N/A 44488307

Supplemental
27

Study Type Species Toxicity Value Toxicity Classification MRID & Status

Lithium salt:

EC25 

NOAEC= 0.003 lbs ai/A

= 0.0060 lbs ai/A N/A 44488307

Supplemental

*The EC05 is used in lieu of the NOAEC

4.3. Incident Database Review

A review of the Ecological Incident Information System (EIIS) database for incidents involving 

bromacil was conducted on February 27, 2012. Forty-two incidents are reported in the database 

(Appendix C) encompassing reports from 1992 through 2009. Of these, 37 are plant incidents 

that occurred from use on agricultural areas (including citrus, peanut, corn, and 

pasture/fencerows), and uses on home and rights of way sites; the incidents ranged in certainty 

from ‘possible’ to ‘highly probable’. The magnitude of the incidents varied from three to 100 

acres. In addition to the plant incidents, there is one aquatic incident with a certainty of ‘highly 

probable’, three with a certainty of ‘probable,’ and one classified as ‘possible.’ One of the three

‘probable’ reports indicates a fish kill of hundreds of white sucker, notropis minnow, American 

eel, and blacknose dace in a stream in Delaware; the next ‘probable’ report indicated a fish kill of 

600 unidentified fish in a Louisiana stream (the sole ‘highly probable’ report indicated a kill of 

hundreds of unidentified species in a Louisiana stream following intentional misuse); and the 

third ‘probable’ report was not explicit regarding species or number of individuals dead in an 

Iowa stream. The incident classified as ‘possible’ reported the death of some catfish in a pond 

adjacent to a use site in Mississippi.

Similarly, a search of the Avian Incident Monitoring System (AIMS; 

http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/index.cfm) was conducted. 

AIMS is a database administered by the American Bird Conservancy that contains publicly 

available data on reported avian incidents involving pesticides. No incidents with bromacil were 

reported via AIMS.

Pesticide registrants report certain types of incidents to the Agency as aggregate counts of 

incidents occurring per product per quarter. Thirteen aggregated plant incidents have been 

reported to the Agency associated with bromacil since 1998. Unless further information 

regarding these aggregate incidents is discovered, it will be assumed that they resulted from 

registered uses. 

4.4. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scope; therefore, it may not be possible to identify 

specific ecosystems during the development of a nation-wide ecological risk assessment. 

However, in general terms, terrestrial ecosystems potentially at risk could include the treated 

field and immediately adjacent areas that may receive drift or runoff. Areas adjacent to the 

treated site could include cultivated fields, fencerows and hedgerows, meadows, fallow fields or 

grasslands, woodlands, riparian habitats and other uncultivated areas. 

Aquatic ecosystems potentially at risk include water bodies adjacent to, or downstream from, the 

treated field and could include impounded bodies such as ponds, lakes and reservoirs, or flowing 
28

waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also includes 

marine ecosystems, including estuaries. 

5. Assessment Endpoints

Assessment endpoints represent the actual environmental value that is to be protected, defined by 

an ecological entity (species, community, or other entity) and its attribute or characteristics 

(USEPA 1998). For bromacil, the ecological entities may include the following: birds, 

mammals, terrestrial-phase amphibians, reptiles, freshwater fish and invertebrates, aquatic-phase 

amphibians, estuarine/marine fish and invertebrates, terrestrial plants, terrestrial invertebrates, 

and aquatic plants. The attributes for each of these entities include growth, reproduction, and 

survival.

6. Conceptual Model

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

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

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

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

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

The conceptual model for bromacil provides a written description (risk hypothesis) and visual 

representation (conceptual diagram) of the predicted relationships between bromacil, potential 

routes of exposure, and the predicted effects for the assessment endpoint. A conceptual model 

consists of two major components: risk hypothesis and a conceptual diagram (USEPA 1998).

Based on the available data, bromacil is water soluble. It is stable in neutral to acidic water, but 

is increasingly unstable in alkaline conditions. Bromacil is persistent in soil under aerobic 

conditions, but assumed to be stable in soil and sediment under anaerobic conditions until data 

are available. It is mobile in soil and is semi-volatile. Bromacil appears to have the potential to 

leach into groundwater, which is supported by monitoring data, or move offsite into surface 

water. Given its relatively low Log Kow and BCF, bromacil is not expected to bioaccumulate in 

aquatic or terrestrial food chains.

6.1. Risk Hypothesis

Risk hypotheses are specific assumptions about potential adverse effects (i.e., changes in 

assessment endpoints) and may be based on theory and logic, empirical data, mathematical 

models, or probability models (U.S. EPA, 1998). For this assessment, the risk is stressor-linked, 

where the stressor is the release of bromacil and bromacil lithium to the environment. The 

following risk hypotheses are presumed for this national-level ecological risk assessment:

Given the uses of bromacil and its environmental fate properties, there is a likelihood of 

exposure to non-target terrestrial and aquatic organisms. When used in accordance with the 

label, bromacil may result in potential adverse effects upon the survival, growth, and 

reproduction of non-target terrestrial and aquatic organisms. 
29

Additionally, bromacil is a uracil herbicide that is known to leach through the soil profile, and 

has been shown to contaminate groundwater resources. Therefore, bromacil has the potential to 

result in risk to terrestrial non-target plants irrigated with contaminated ground water. 

6.2. Conceptual Diagram

The conceptual model used to depict the potential ecological risk associated with the use of 

bromacil assumes that as a pesticide, bromacil can adversely affect terrestrial and aquatic 

organisms (the receptors) if environmental concentrations exceed toxic thresholds as a result of 

application according to the label directions (Figures 2 and 3). Ecological receptors that may 

potentially be exposed to bromacil include terrestrial and semi-aquatic wildlife (e.g., mammals, 

birds, terrestrial-phase amphibians and reptiles), terrestrial and semi-aquatic plants, and 

terrestrial invertebrates (e.g., honey bees). Additionally, aquatic organisms (i.e., freshwater and 

estuarine/marine fish and invertebrates, aquatic-phase amphibians, and aquatic plants) are 

potential receptors in adjacent water bodies through off-site transport of bromacil from the 

application site through runoff, erosion, and spray drift.
30

Figure 2. Conceptual model for bromacil exposure to aquatic organisms. Dashed lines indicate 

low-likelihood routes of exposure.

Stressor

Source

Receptors

Attribute

Change

Bromacil and Bromacil Lithium Salt

Spray drift

Fish/aquatic-phase 

amphibians

Eggs 

Larvae 

Juveniles / Adults

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Surface water

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Atmospheric 

transport

Wet/dry deposition

Soil Ground water

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plant

terrestrial 

exposure 

pathways see 

Figure 2
31

Figure 3. Conceptual model for bromacil exposure to terrestrial organisms. Dashed lines 

indicate low-likelihood routes of exposure.

7. Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the environment will 

be estimated. The use, environmental fate, and ecological effects of bromacil will be 

characterized and integrated to assess the risks. This will be accomplished using a risk quotient 

(ratio of exposure concentration to effects concentration) approach. Although risk is often 

defined as the likelihood and magnitude of adverse ecological effects, the risk quotient-based 

approach does not provide a quantitative estimate of likelihood and/or magnitude of an adverse 

effect. However, as outlined in the Overview Document (USEPA 2004), the likelihood of 

effects to individual organisms from particular uses of bromacil may be estimated using the 

probit dose-response slope and either the level of concern (discussed below) or the actual 

calculated risk quotient value. 

This analysis plan will be revisited and may be revised depending upon the information 

submitted by the public in response to the opening of the Registration Review docket for 

bromacil.

Stressor

Source

Receptors

Attribute

Change

Bromacil and Bromacil Lithium Salt

Direct

application Spray drift

Birds / Terrestrialphase amphibians 

/ reptiles / 

mammals/ Insects

Terrestrial 

inverts

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey

Habitat integrity

Reduction in primary 

productivity

Reduced cover

Community change

Terrestrial/riparian plants

grasses/forbs, fruit, seeds 

(trees, shrubs)

Runoff

Mammals

Exposure

Media

Soil

Ingestion

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion

Atmospheric 

transport

Root uptake

Wet/dry 

Birds / 

Amphibians

Ingestio
32

7.1. Stressors of Concern

Bromacil has registered products that contain multiple active ingredients, including diuron; 2,4-

dichlorophenoxyacetic acid; sodium chlorate; sodium metaborate; and 2,4-

dichlorophenoxyacetic acid, isooctyl ester. Analysis of the available acute oral mammalian LD50

data (and available open literature for bromacil) for multiple active ingredient products relative 

to the single active ingredient were provided in Appendix A of the 2007 California Red-legged 

Frog assessment (USEPA 2007). The results of that analysis showed that an assessment based 

on the toxicity of the single active ingredient of bromacil or bromacil lithium would be

appropriately conservative since the technical grade active ingredient is more toxic than the 

formulated end product. However, the assessed species and their environments may be exposed 

to multiple pesticides simultaneously, and the interactions of other toxic agents (not captured in 

the available mixture toxicity data) with bromacil could potentially result in additive effects, 

synergistic, or antagonistic effects. 

The Agency does not routinely include, in its risk assessments, an evaluation of mixtures of 

active ingredients, either those mixtures of multiple active ingredients in product formulations or 

those in the applicator’s tank. In the case of the product formulations of active ingredients (that 

is, a registered product containing more than one active ingredient), each active ingredient is 

subject to an individual risk assessment for regulatory decision regarding the active ingredient on 

a particular use site. If effects data are available for a formulated product containing more than 

one active ingredient, the data may be used qualitatively or quantitatively in accordance with the 

Agency’s Overview Document and the Services’ Evaluation Memorandum (U.S., EPA 2004; 

USFWS/NMFS 2004). 

Although bromacil photodegrades rapidly in alkaline conditions, information on photodegradates 

is not available. In neutral pH soil (pH 6.6), bromacil degrades slowly (half-life of 275 days), 

and CO2 is the only major degradate. Five aerobic soil minor degradates were identified, but 

were present at only 0.6-3.4% of total residues. The major and persistent anaerobic aquatic 

degradate, 3-sec-butyl-6-methyluracil (Metabolite F), which represented a maximum of 80.7% of 

the applied (day 304), was not determined to be of toxicological concern for the human health 

risk assessment (Linda Taylor, HED/OPP) in the bromacil RED; this determination of residues 

of concern also applies to the ecological risk assessment (i.e., only the parent bromacil is 

included for assessment of risk for ecological systems).

7.2. Measures of Exposure

Measures of exposure are based on aquatic and terrestrial models that predict estimated 

environmental concentrations (EECs) of bromacil using maximum labeled application rates and 

methods cited in Section 3.2. The models used to predict aquatic EECs are the Pesticide Root 

Zone Model coupled with the Exposure Analysis Model System (PRZM/EXAMS). The model 

used to predict terrestrial EECs on food items is T-REX. The model used to derive EECs 

relevant to terrestrial and wetland plants was TerrPlant. These models are parameterized using 

relevant reviewed registrant-submitted environmental fate data. Model input values will be 

consistent with the most recent version of the input parameter guidance (Version 2.1; USEPA 

2009).
33

PRZM (v3.12.2; 5/15/05) and EXAMS (v2.98.04.06; 4/25/05) are simulation models coupled 

with the linkage program shell: PE5 (PRZM EXAMS Model Shell; v5.0; 11/15/06), which 

incorporates the standard scenarios developed by EFED. The models generate daily exposures 

and calculated 1-in-10 year EECs of bromacil. PRZM simulates pesticide fate and transport as a 

result of leaching, direct spray drift, runoff and erosion from an agricultural field, and EXAMS 

estimates environmental fate and transport of pesticides in a surface water body for a 30-year 

period. The combined model is designed to estimate pesticide concentrations found in water 

(standard pond) at the edge of the treated field. As such, it provides high-end values of the 

pesticide concentrations that might be found in ecologically sensitive environments following 

pesticide application. The location of the field is specific to the crop being simulated using sitespecific information on the soils, weather, cropping, and management factors associated with the 

scenario. The crop/location scenario is intended to represent a high-end exposure site on which 

the crop is normally grown. Based on historical rainfall patterns, the receiving water body 

receives multiple runoff events during the years simulated. Weather and agricultural practices 

are simulated for 30 years so that the 10-year exceedance probability at the site can be estimated. 

The simulation is generated using 30 years of meteorological data, encompassing the years from 

1961 to 1990. Additional information on these models can be found at: 

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

The standard scenarios used for ecological pesticide assessments assume application to a 10-

hectare agricultural field that drains into an adjacent 1-hectare water body that is 2 meters deep 

(20,000 m3 volume) with no outlet. PRZM/EXAMS is used to estimate screening-level exposure 

of aquatic organisms to bromacil. The measure of exposure for aquatic species is the 1-in-10 

year return peak or rolling mean concentration. The 1-in-10 year peak is used for estimating 

acute exposures of direct effects to aquatic organisms. The 1-in-10-year 60-day mean is used for 

assessing chronic exposure to fish and aquatic-phase amphibians. The 1-in-10-year 21-day mean 

is used for assessing chronic exposure to aquatic invertebrates.

Exposure estimates for terrestrial organisms assumed to be in the target area or in an area 

exposed to off-site deposition are derived using the T-REX model (version 1.4.1, 10/09/2008). 

This model incorporates the Kenaga nomograph, as modified by Fletcher et al. (1994), which is 

based on a large set of field residue data. The upper limit values from the nomograph represent 

the upper bound of residue values from actual field measurements (Hoerger and Kenaga 1972). 

The Fletcher et al. (1994) modifications to the Kenaga nomograph are based on measured field 

residues from 249 published research papers, including information on 118 species of plants, 121 

pesticides, and 17 chemical classes. Based on these data, T-REX assumes a 35-day foliar 

dissipation half-life in the absence of other data.

In order to determine if more data are necessary, the Screening Tool for Inhalation Risk (STIR 

v.1.0) was used to calculate an upper bound estimate of exposure using bromacil’s vapor 

pressure and molecular weight for vapor phase exposure as well as the maximum application rate 

and method of application for spray drift. STIR incorporates results from several toxicity studies 

including acute oral and inhalation rat toxicity endpoints obtained from the “six-pack” of core 

studies, which are a series of six guideline studies that are submitted to the Registration Division 

of the Office of Pesticide Programs for technical and formulated products of a pesticide as well 
34

as the most sensitive acute oral avian toxicity endpoint. Based on the results of the STIR model, 

inhalation exposure alone was not determined to be a potential pathway of concern for avian or 

mammalian species on an acute exposure basis. 

Inhalation exposure via spray drift and/or vapor-phase of the pesticide alone does not appear to 

be of concern. The analysis of the inhalation route of exposure in STIR does not consider that 

aggregation with other exposure pathways such as dietary, dermal, or drinking water may 

contribute to a total exposure that has a potential for effects to non-target animals. However, the 

Agency does consider the relative importance of other routes of exposure in situations where 

data indicate that pesticide exposures through other routes may be potentially significant

contributors to wildlife risk (USEPA, 2004). The risk assessment will discuss the impact of 

consideration of other routes of exposure that have been identified as potentially important and 

the degree of certainty associated with screening-level risk assessment conclusions. Detailed 

information about STIR v.1.0, as well as the tool, can be found on the EPA’s website at:

http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial.

The Screening Imbibition Program (SIP v.1.0) was used to calculate an upper bound estimate of 

exposure using bromacil’s solubility, the most sensitive acute and chronic avian and mammalian 

toxicity endpoints. Drinking water exposure alone was determined to be a potential pathway of 

concern for both avian (and surrogates) and mammalian species on an acute and chronic 

exposure basis. This route of exposure will be considered further in the risk assessment. 

This pathway will be explored further with the development of SIP v.2.0 in the risk assessment 

for bromacil. Detailed information about the SIP v.1.0, as well as the tool, can be found on the 

EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial.

EECs for terrestrial plants are derived using TerrPlant (v.1.2.2). This model uses estimates of 

pesticides in runoff and in spray drift to calculate EECs. EECs are based upon solubility, 

application rate and minimum incorporation depth. 

The AgDRIFT (v2.01; May 2001) or AgDISP (v. 8.15) spray drift model may be used to assess 

exposures of organisms to bromacil deposited on terrestrial habitats by spray drift.

7.3. Measures of Effect

Ecological effects data are used as measures of direct and indirect effects to biological receptors. 

Effects data are obtained from registrant-submitted studies or from literature studies identified by 

the ECOTOX database. 

The acute measures of effect used for animals in this assessment are the LD50, LC50 and EC50. 

LD stands for "Lethal Dose", and LD50 is the amount of a material, given all at once, that is 

estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration” 

and LC50 is the concentration of a chemical that is estimated to kill 50% of the test organisms. 

EC stands for “Effective Concentration” and the EC50 is the concentration of a chemical that is 

estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic 

measures of exposure for listed and non-listed animals are the NOAEL/NOAEC and NOEC. 
35

NOAEL stands for “No Observed-Adverse-Effect-Level” and refers to the highest tested dose of 

a substance that has been reported to have no harmful (adverse) effects on test organisms. The 

NOAEC (i.e., “No-Observed-Adverse-Effect-Concentration”) is the highest test concentration at 

which none of the observed effects were statistically different from the control. For non-listed 

plants, only acute exposures are assessed (i.e., EC25 for terrestrial plants and EC50 for aquatic 

plants); for listed plants the NOAEC (or, when a NOAEC is not available, the EC05) is used. 

Where available, sublethal effects observed in both registrant-submitted and open literature 

studies will be evaluated qualitatively. Such effects may include behavioral changes (e.g., 

lethargy and changes in coloration). Quantitative assessments of risks, though, are limited to 

those endpoints that can be directly linked to the Agency’s assessment endpoints of impaired 

survival, growth and reproduction.

In the absence of taxon-specific data, the assessment of risk for direct effects to non-target 

organisms makes the assumption that toxicity of bromacil to birds is similar to terrestrial-phase 

amphibians and reptiles. Likewise, the toxicity of bromacil to fish is assumed to be similar to

aquatic-phase amphibians. In the absence of data for either acute or chronic effects, the 

conservative assumption will be to presume that bromacil is toxic. 

7.4. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effects characterization to 

determine the potential ecological risk from the registered uses of bromacil and the likelihood of 

direct and indirect effects to non-target organisms in aquatic and terrestrial habitats. The 

exposure and toxicity effects data are integrated in order to evaluate the risks of adverse 

ecological effects on non-target species. For the assessment of bromacil risks, the risk quotient 

(RQ) method is used to compare exposure and measured toxicity values. EECs are divided by 

acute and chronic toxicity values. The resulting RQs are then compared to the Agency’s Levels 

of Concern (LOCs) (USEPA 2004). These criteria are used to indicate when bromacil use, as 

directed on the labels, has the potential to cause adverse direct or indirect effects to non-target 

organisms. In addition, incident data from the EIIS will be considered as part of the risk 

characterization. 

7.5. Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the deterministic point-estimate 

(RQ) based approach described in the risk assessment. An effort will be made to further 

qualitatively describe risk using probabilistic tools that the Agency has developed. These tools 

have been reviewed by FIFRA Scientific Advisory Panels 

(http://www.epa.gov/scipoly/sap/index.htm) and have been deemed as appropriate means of 

refining assessments where deterministic approaches have identified risks. Newer tools may be 

available to assess the routes of exposure (e.g. TIM and SWAMP models) and will be applied as 

appropriate in Registration Review.

7.6. Endocrine Disruptor Screening Program
36

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (EDSP) to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by 

a “naturally occurring estrogen, or other such endocrine effects as the Administrator may 

designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect.

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first 

group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors.

Bromacil is not among the group of 58 pesticide active ingredients on the initial list to be 

screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide 

chemicals. Accordingly, EPA anticipates issuing future EDSP test orders/data call-ins for all 

pesticide active ingredients. 

For further information on the status of the EDSP, the policies and procedures, the list of 67 

chemicals, the test guidelines and the Tier 1 screening battery, please visit our website: 

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

7.7. Endangered Species Assessment

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to Federally-listed threatened and/or endangered (listed) species from 

registered uses of bromacil. This assessment will be conducted in accordance with the Overview 

Document (USEPA 2004), provisions of the ESA, and the Services’ Endangered Species 

Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associated with the registration of bromacil is based on an action area. 

The action area is considered to be the area directly or indirectly affected by the federal action, as 

indicated by the exceedance of Agency Levels of Concern (LOCs) used to evaluate direct or 

indirect effects. The Agency’s approach to defining the action area under the provisions of the 

Overview Document (USEPA 2004) considers the results of the risk assessment process to 

establish boundaries for that action area with the understanding that exposures below the 

Agency’s defined LOCs constitute a no-effect threshold. For the purposes of this assessment, 

attention will be focused on the footprint of the action (i.e., the area where bromacil application 

occurs), plus all areas where offsite transport (i.e., spray drift, runoff, etc.) may result in potential 

exposure that exceeds the Agency’s LOCs. Specific measures of ecological effect that define the 
37

action area for listed species include any direct and indirect effects and/or potential modification 

of its critical habitat, including reduction in survival, growth, and reproduction as well as the full 

suite of sublethal effects available in the effects literature. Therefore, the action area extends to a 

point where environmental exposures are below any measured lethal or sublethal effect threshold 

for any biological entity at the whole organism, organ, tissue, and cellular level of organization. 

In situations where it is not possible to determine the threshold for an observed effect, the action 

area will initially be assumed to include all counties where bromacil is used in the United States. 

7.8. Drinking Water Assessment

A new drinking water assessment will be conducted with current data, models and simulation 

model guidance to support future human health dietary risk assessments of bromacil. The 

drinking water exposure assessment will be conducted for the maximum labeled use in support 

of the human health dietary risk assessment. The drinking water assessment will incorporate 

model estimates of bromacil in surface water and groundwater including any residues that are 

determined to be of toxicological concern. Concentrations of bromacil in surface waters will be 

estimated using PRZM/EXAMS (see description above) using the Index Reservoir scenario to 

estimate environmental concentrations in drinking water rather than the standard pond used with 

aquatic exposure assessment.

An EDWC of bromacil in groundwater may be estimated using EFED’s Tier I aquatic model 

SCIGROW (Screening Concentration in Ground Water, version 2.3; 8/8/2003), or other 

approved groundwater models at the time of risk assessment. SCIGROW is a regression model 

used as a screening tool to estimate pesticide concentrations found in groundwater used as 

drinking water. The output of SCIGROW represents the concentrations that might be expected 

in shallow unconfined aquifers under sandy soils, which is representative of the groundwater 

most vulnerable to pesticide contamination likely to serve as a drinking water source. 

The drinking water assessment will also include available surface and groundwater monitoring 

data with consideration of changes in use patterns that may have occurred. States are encouraged 

to submit monitoring data for review.

7.9. Environmental Monitoring Data

All monitoring data may be considered to characterize the modeling results and risk estimations 

for bromacil in the environment. States, Tribal Organizations, and other government and nongovernment organizations are encouraged to submit additional surface water and groundwater 

monitoring data for bromacil. Below is a summary of currently available monitoring data from 

publicly available databases (e.g., NAWQA), submitted studies (retro- and prospective 

groundwater monitoring studies), as well as state-level monitoring studies.

USGS NAWQA

A query of the United States Geological Survey’s (USGS) National Water Quality Assessment 

Program (NAWQA)5

 5 USGS NAWQA Program: 

for detections of bromacil in surface water and groundwater, returned 355

http://infotrek.er.usgs.gov/apex/f?p=NAWQA:HOME:0. Accessed February 24, 2012.
38

detections in surface water out of 8,262 samples analyzed from 1,026 sites (concentrations 

ranging from 0.001 to 5.0 ug/L; detection frequency of 4.3 %; MDL ranged from 0.001 to 8.64 

ug/L). Of the 355 detections, 14 exceeded the lowest concentration know to cause effects (1.1 

ppb) to non-vascular plants. For groundwater, 155 detections were reported out of 6,476

samples analyzed for bromacil (detected concentrations ranging from 0.003 to 21.74 ug/L; a 

detection frequency of <3 %; MDL ranged from 0.003 to 1.33). Of the 155 detections, 18 were 

greater than the lowest concentration know to cause effects (1.1 ppb) to non-vascular plants. 

Although the detection frequencies are low for surface water and groundwater, these detections 

illustrate that bromacil may contaminate both surface water and groundwater resulting from use

of the compound. 

USGS/USEPA Pilot Reservoir Monitoring Study

In 1999, a pilot monitoring program was initiated by the USGS and the U.S. Environmental 

Protection Agency to provide information on pesticide concentrations in drinking water and to 

assist in the implementation of the Food Quality Protection Act of 1996. Twelve water-supply 

reservoirs were sampled, ranging in size from 120 to 92,600 acre-feet normal capacity, with 

contributing watersheds ranging from 3.3 to 784 square miles. The sites are in California, 

Indiana, Ohio, Oklahoma, Louisiana, Missouri, South Carolina, South Dakota, New York, North 

Carolina, Pennsylvania, and Texas. Analyses for pesticides in water samples were performed at 

the USGS National Water Quality Laboratory in Denver, Colorado, using three analytical 

methods. Overall, these methods included 178 different pesticides and degradation products. 

Bromacil was included as one of the analytes in this study. Bromacil was detected in both source 

water and finished water. In source water bromacil was detected at a maximum concentration of 

0.481 ug/L (detection frequency of 15.7%; 49 detections – 47 confirmed – out of 312 samples of 

raw water; MRL = 0.081 ug/L). In the 225 samples of finished water, bromacil was detected two 

times at a maximum concentration of 0.481 ug/L (detection frequency of 0.9%; MRL = 0.081 

ug/L). 

Retrospective Groundwater Monitoring Study

DuPont conducted retrospective groundwater monitoring studies in three citrus-growing regions 

(Central Ridge, Flatwoods and Coastal) of Florida between 1987 and 1990 (USEPA, 1993; 

DP191409, 191677). Bromacil was detected in groundwater at all three study sites. A brief 

summary of the results for each site is provided below.

Central Ridge: Bromacil was detected in all 10 wells at this site, with well depths 

ranging from 14 to 54 feet. Five of these wells had at least one detection above the 90 

ppb Health Advisory Level (HAL), with a maximum concentration of 156 ppb. 

Concentrations of bromacil at this site did not decrease with time in these monitoring 

wells, although the application rate of bromacil was decreased throughout the study.

Flatwoods: Bromacil was detected in all three of the monitoring wells installed at this 

site, with a maximum detection of 21.8 ppb.
39

Coastal: Bromacil was detected in three of the four monitoring wells at this site, with a 

maximum concentration of 147 ppb. The three wells with detections were screened from 

5 to 10 feet. The single well without detections was screened from 50 to 60 feet.

Prospective Groundwater Monitoring Study

DuPont conducted a prospective groundwater monitoring study (MRID 44480701) in response to 

the GDCI issued following the RED. It was designed to evaluate the potential for bromacil to 

leach to groundwater in Florida’s Central Ridge region required by both the USEPA and Florida 

Dept. of Agriculture and Consumer Services as part of a proposed bromacil management 

strategy. This study is currently under review by the Agency. A preliminary review of the data 

showed that the maximum detected concentration in shallow, intermediate, and deep wells, 

respectively were 55.2, 43.2 and 38 ppb. It is important to note that bromacil concentrations as 

high as 27 ppb were detected in the control well. However these detected concentrations were 

less than the detections – except for the Florida Flatwoods site – reported in the previous 

retrospective groundwater monitoring study conducted prior to the implementation of label 

mitigations. 

State Groundwater Monitoring Studies

The data and discussion below for monitoring studies in Florida, Texas and California was 

discussed in the 1996 RED (USEPA, 1996). For Registration Review, the Agency will update 

the current database for bromacil. It should be noted that the data included below were provided 

to the Agency prior to the implementation of mitigation measures of bromacil application rates.

1) Florida: Although bromacil is used in many states, the greatest use has been on citrus crops in 

Florida. In addition, the most extensive groundwater monitoring for bromacil has been in 

Florida. As a result of this monitoring, it has become clear that contamination of groundwater 

with bromacil has occurred to varying degrees throughout the citrus growing regions of the state.

Bromacil was one of the pesticides tracked in Florida's Pesticide Contamination Monitoring 

System. This system kept a running total of ground water samples analyzed for bromacil, and 

the number of samples with concentrations above and below the 90 ppb health advisory level. 

This system is no longer in place, however, as of May 1995, 2,837 wells were sampled for 

bromacil; 899 had detections below the HAL (90 pbb), and 57 had detections above the HAL.

Of this number, 679 of the wells with detections below the HAL, and 55 with detections above 

the HAL were from Highlands County, in the Central Ridge. Polk County recorded 121 wells 

with detections below the HAL, and 1 above the HAL. Lake County followed with 70 wells 

with detections below the HAL, then Hardee County with 16 wells with detections below and 

one with detections above the HAL.

A separate study performed in Collier County, in the Flatwoods region of southern Florida, had 

detections well above the HAL in shallow ground water. In a report on this study, detections of 

bromacil in ground water are listed at concentrations as high as 1,422 ppb. These samples were 

collected at the very top of the water table, from wells with one-foot screens. The State of 

Florida does not consider bromacil to be a ground water concern in the Flatwoods region, as 
40

there is generally a low-permeability spodic layer near the surface, perching this uppermost 

saturated zone. However, as a result, the contaminated shallow ground water is available for 

transport into surface water through drainage ditches.

2) Texas: While bromacil use is greatest in Florida, significant amounts are also applied in 

California and Texas for both citrus and right-of-way uses. The Agency’s "Pesticides in Ground 

Water Data base" reports that bromacil was detected in 6 of 230 wells sampled in Texas between 

1983 and 1989.

3) California: In 1994, the Department of Pesticide Regulation of the California Environmental 

Protection Agency (CalEPA) reported that bromacil was one of 5 pesticides for which detections 

were "verified" in California groundwater as a result of non-point agricultural use within the past 

year. CalEPA defines a detection as "verified" when (a) the pesticide (or breakdown product) is 

detected in two discrete samples taken from a single well during a 30-day period AND (b) the 

second sample is analyzed either by the same laboratory using different analytical methods or by 

two laboratories using the same method (analytical methods must have been approved by the 

department of pesticide regulators). Bromacil was detected in two other wells but these 

detections could not be verified because bromacil was not detected in the second discrete 

samples from these wells. Bromacil detection was verified in 4 wells in 2 counties in 1994 

where it had not been previously detected and found but not verified in two new wells in two 

other counties. For the risk assessment, an attempt will be made to update the database for 

bromacil in groundwater resources in California.

In California, the quality of groundwater is managed by the use of Pesticide Management Zones 

(PMZs). A PMZ is an approximately square-mile area designated as sensitive to ground water 

contamination. PMZs are created based on verified detections in groundwater of a particular 

pesticide residue. PMZs are chemical specific; there are bromacil PMZs, simazine PMZs, diuron 

PMZs, etc. CalEPA monitors compliance within PMZs to ensure pesticides are not reapplied in 

these areas, and to determine if previously detected residues are still present in the soil. Previous 

data included in the RED reported residues of bromacil in three of five PMZs at levels ranging 

from 50 to 240 ppb. These residues were considered to have resulted from normal agricultural 

use before the PMZ was established. For the risk assessment, an attempt with me made to 

update these data sources with current data, and analyze the impact of the establishment of PMZs 

on bromacil detections in groundwater. States are encouraged to submit monitoring data to 

support its use in risk assessment.

7.10. Clean Water Act

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

section 303(d) of the Clean Water Act6

. In addition, no Total Maximum Daily Loads (TMDL) 

have been developed for the herbicide7. The Impaired Waters and Total Maximum Daily Loads 

website can be consulted for more information8

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

. The Agency invites submission of water quality 

7

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

group_name=PESTICIDES

8 http://www.epa.gov/owow/tmdl/
41

data for this pesticide. To the extent possible, data should conform to the quality standards in 

Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and 

Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management 

Process9

, in order to ensure they can be used quantitatively or qualitatively in pesticide risk 

assessments.

8. Data Gaps and Uncertainties

8.1. Environmental Fate

The studies submitted to fulfill environmental fate data requirements for bromacil are not 

sufficient to conduct an exposure assessment; seven data requirements have not been met as 

stipulated in 40 CFR part 158 Subpart N §158.1300 for all pesticides with use patterns for 

terrestrial food and nonfood applications. Table 8.1 catalogues the classifications for submitted 

studies on the environmental fate and transport of bromacil. Listed below are the identified data 

gaps and what would be assumed in the absence of these data.

• Aqueous Photodegradation (835.2240):

•

Although there are no acceptable studies, the 

Agency does not anticipate recommending a new study be conducted as a new study 

would not yield significantly different results.

Aerobic Soil Metabolism (835.4100)

•

: The guideline stipulates that data from at least four 

relevant soils of different organic carbon content, pH, clay content, and microbial 

biomass must be submitted in order to characterize the variability in aerobic 

biodegradation of bromacil in the environment. The Agency currently has data from one 

soil in the submitted study. In absence of additional data, the Agency will multiply the 

single degradation half-life by three for the purposes of estimating aquatic exposure to 

account for the potential variability in degradation rates between different soil types.

Anaerobic soil metabolism (835.4200)

•

. Currently, there are no available data. In lieu of 

acceptable data, bromacil is assumed to be stable to metabolism in soil in oxygen limiting 

environments.

Aerobic Aquatic Metabolism (835.4300)

•

. Data requirement was previously waived due to 

modifications to the label for bromacil avoiding use sites with high potential to result in 

aquatic exposure (USEPA, 1992; DP 182792). In lieu of this data, aquatic exposure

modeling for risk assessment will assume a half-life value equal to 2x the aerobic soil 

metabolism input (resulting in a 6x factor).

Anaerobic Aquatic Metabolism (835.4400):

•

Currently there are no acceptable data for 

anaerobic aquatic metabolism. This study is necessary to understand the degradation of 

bromacil in oxygen-limiting environments. In lieu of additional acceptable data, stability 

is assumed.

Adsorption/desorption Batch Equilibrium (835.1230):

 9 http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf

Studies submitted only include soil 

column leaching data. Batch equilibrium data are needed to determine the sorption 

coefficient for bromacil. In absence of these data, experimental organic carbon 

partitioning coefficients will be used from open literature sources (e.g., Gersch, 1984 and 

Corwin and Farmer, 1984).
42

• Terrestrial Field Dissipation (835.6100): The original study conducted at two bareground sites was classified acceptable. It was noted in the review that to fulfill the 

guideline additional studies are required on different soils that capture the use areas for 

bromacil (e.g., highly permeable citrus production areas of Florida). Based on open 

literature data for sorption coefficients and monitoring data, the Agency does not 

anticipate needing additional data on the field dissipation of bromacil.

Table 8.1 identifies studies by MRID that offer data for each guideline requirement, as well as 

study classifications and whether or not further data are needed in order to support risk 

assessment (i.e., whether there is a data gap).

Table 8.1. Summary of available environmental fate data.

Guideline No. Data Requirement MRID / 

ACC No. Classification

Are 

Additional 

Data Needed 

for Risk 

Assessment?

Comments

835.2120 Hydrolysis

40951505 Acceptable No Stable at pH 5,7 and 9 @ 25oC.

40951506 Acceptable Classified acceptable.

835.2240 Photodegradation in 

Water

40951507 Supplemental No, 

bromacil is 

photolytically 

stable at neutral 

and acidic pHs, 

and is 

photolabile in 

alkaline 

conditions

The portion of study conducted at pHs 

5 and 7 is acceptable. MRID 40951508 

provided additional information for 

photodegradation at pH 9.

40951508 Supplemental

Study was originally classified as 

upgradeable because data on degradates 

were not provided for alkaline pH (9).

00126338 Supplemental

Orginial study was not reviewed, but 

results are similar to those in MRIDs 

40951507 and 40951508.

5018069 Supplemental

835.2410 Photodegradation on 

Soil 40951509 Acceptable No Stable to photodegradation on soil.

835.4100 Aerobic Soil 

Metabolism 40951510 Acceptable

Yes,

Additional soils 

would reduce 

uncertainty with 

using a single 

value.

Only one soil was used in laboratory 

study. Data from 3 additional soils are 

needed to determine degradation kinetics. 

In lieu of these data the single value is 

multiplied by 3 to account for potential 

variability in the degradation rate in 

different soil types.

835.4200 Anaerobic Soil 

Metabolism No Data -- Yes No data available. In lieu of these data stability is assumed.

835.4300 Aerobic Aquatic 

Metabolism No Data --

Yes, 

In lieu of this data 

risk assessment 

will assume 2x 

aerobic soil 

metabolism input 

(resulting in a 6x 

factor).

Data requirement was previously waived 

due to modifications to the label for 

bromacil avoiding use sites with high 

potential to result in aquatic exposure. 

Potential use sites include applications 

near surface water therefore this data is 

need for risk assessment.
43

Guideline No. Data Requirement MRID / 

ACC No. Classification

Are 

Additional 

Data Needed 

for Risk 

Assessment?

Comments

835.4400 Anaerobic Aquatic 

Metabolism 40951511 Unacceptable

Yes, 

in lieu of 

additional 

acceptable data, 

stability is 

assumed.

Study provides supplemental data and 

cannot be upgraded. 

835.1240 Mobility - Column 

Leaching 40951512 Supplemental

Yes,

in absence of 

additional data, 

values from 

Corwin and 

Farmer, 1984 

and/or Gerstl, 

1984 will be used.

Studies submitted only include soil 

column leaching data. Batch equilibrium 

data are needed to determine sorption 

coefficients of bromacil. 

835.6100 Terrestrial Field 

Dissipation 41677101 Acceptable No

Additional studies were required on 

different soils that capture the use areas 

for bromacil. However, open literature 

data and groundwater studies provide 

adequate information about the 

dissipation pathways of bromacil in the 

environment, therefore the Agency does 

not anticipate requesting additional field 

studies at this time.

850.1730 Fish Accumulation 40951513 Acceptable No

835.7100 Groundwater, Smalscalel Prospective 44480701 In Review No Currently under review by the Agency.

-- Groundwater Smallscale Retrospective No MRID Supplemental No

No MRID in OPPIN. Review and 

discussion of use of data included in 

USEPA, 1993.

8.2. Ecological Effects

For Registration Review, the following studies are requested to resolve uncertainties in the risk 

assessment:

• Mysid chronic toxicity test with bromacil TGAI (850.1350):

•

 No data have been received 

to characterize the chronic toxicity of bromacil to the estuarine invertebrate 

Americamysis bahia. Data are required on one estuarine/marine invertebrate species

under the data requirements (40 CFR §158.630) for conventional pesticides. In acute 

testing, estuarine invertebrates (i.e., A. bahia) were found to be more sensitive to 

bromacil than freshwater invertebrates (Daphnia sp.). In the absence of data, chronic 

toxicity to marine/estuarine taxa will be derived from available chronic freshwater 

invertebrate data.

Avian acute oral toxicity test with bromacil TGAI (850.2100): Acute avian oral toxicity 

data are needed for either one waterfowl or one upland game species and one passerine 

species under the data requirements (40 CFR §158.630) for conventional pesticides. 

Based on a preliminary screen using the highest agricultural application scenario for 

bromacil (see Table 3.1), the highest peak dose-based EEC is 3,280 mg/kg bw. 
44

Available avian acute oral toxicity data to the bobwhite quail determined a no effects 

level at 2,250 mg/kg bw; well below the maximum field application rate (i.e., the 

environmentally relevant concentration). In order to properly characterize risk to birds, a 

new study dosing the bobwhite quail at the maximum label rate is necessary for risk 

assessment. Testing with the bobwhite quail is requested because of mortalities recorded 

in a previous dietary study with this species (MRID 00013295), and frank sublethal 

effects in an acute oral study with this species (MRID 40951501).

• Avian sub-acute dietary toxicity test with bromacil TGAI (850.2200):

•

No data are 

available to define the sub-acute (dietary) exposure of technical bromacil to birds. In the 

absence of new data, endpoints from a study involving dietary exposures of birds to a 

formulated product containing bromacil will be used in risk assessment.

Terrestrial plant seedling emergence and vegetative vigor toxicity tests, Tier II (850.4100 

and 850.4150): Tier II terrestrial plant seedling emergence and vegetative vigor studies 

conducted with a typical end-use product (TEP) test substance are requested. All 

currently available terrestrial plant studies were conducted with TGAI rather than TEP as 

specified in 40 CFR §158.660. An additional line of evidence supporting this data 

request comes from the 37 reported incidents involving terrestrial plants (See Appendix 

C).
45

Table 8.2. Summary of available ecological effects data.

Guideline No. Data Requirement MRID / 

ACC No. Classification

Are Additional 

Data Needed for 

Risk 

Assessment?

Comments

850.1075 Acute – Freshwater Fish 40951503 Acceptable No --

850.1075

Acute –

Saltwater Fish 41588702 Acceptable No --

850.1400

Chronic – Freshwater 

Fish 44566101 Supplemental No

The endpoints are useful for 

risk assessment. A

retrospective groundwater 

study (conservative EEC 

scenario) indicates that EECs 

are below concentrations of 

chronic concern.

850.1400 Chronic – Saltwater Fish No Data -- No

Chronic toxicity data are 

available for freshwater fish, 

which were more acutely 

sensitive than saltwater fish.

850.1035

Acute –

Estuarine/Marine 

Invertebrate

41588701 Acceptable No --

850.1010

Acute – Freshwater 

Invertebrate 40951504 Acceptable No --

850.1300

Chronic – Freshwater 

Invertebrate 44566401 Acceptable No --

850.1350

Chronic –

Estuarine/Marine 

Invertebrate No Data -- Yes

Estuarine invertebrates tested 

more acutely sensitive to 

bromacil than freshwater 

invertebrates. In the absence 

of data, chronic toxicity to 

marine/estuarine taxa will be 

derived from chronic

freshwater invertebrate data.*

850.5400

Aquatic – Non-vascular 

Plants 42516401 Acceptable No --
46

Guideline No. Data Requirement MRID / 

ACC No. Classification

Are Additional 

Data Needed for 

Risk 

Assessment?

Comments

850.4400

Aquatic – Vascular 

Plants 46095401 Acceptable No --

850.4100

Terrestrial plant 

Seedling emergence-Tier 

II

42491101,

44488307 Supplemental Yes

These studies were conducted 

with TGAI. 40 CFR 

§158.660 specifies that TEP 

should be used.

850.4150

Terrestrial plant 

Vegetative vigor-Tier 

II

42491101,

44488307 Supplemental Yes

These studies were conducted 

with TGAI. 40 CFR §158.660 

specifies that TEP should be 

used. Reported incidents 

involving terrestrial plants 

support the request for 

additional data.

850.2100 Acute – Avian Oral

(bobwhite quail)

40951501 Acceptable Yes

An avian acute oral study 

testing bobwhite quail at 

environmentally relevant 

rates is requested.

850.2200

Acute – Avian 

Dietary

(bobwhite quail, 

mallard)

00013295, 

00013296 Acceptable Yes

No data is available to define 

the avian dietary toxicity of 

technical bromacil. In the 

absence of data, a study 

involving dietary exposures 

of birds to a formulated 

product containing bromacil 

will be used to assess avian 

dietary risk. 

850.2300 Chronic – Avian 

Reproduction

44844601, 

44844801 Acceptable No --

850.3020 Honey Bee Acute 

Contact Toxicity

00009181 Supplemental No

The LD50 was not determined 

in the limit test, which 

indicates that the compound 

is practically nontoxic to 

honey bees.

* A NOAEC could be estimated using acute-to-chronic ratio for Daphnia magna of 14.8 (acute =121; chronic=8.2; 

121/8.2=14.8). This would result in a mysid NOAEC of 7.7 ppm.
47

8.3. Usage Specific Uncertainties

Bromacil usage data for pineapple grown in Hawaii is not quantified by the currently available 

information, presenting considerable uncertainty since Hawaii has the highest number of listed 

plant and animal species of any state (USFWS, 2011). As of 13 April 2010, 343 Hawaiian Island 

plants were listed as Endangered, and 11 were listed as Threatened (USFWS, 2011). EFED 

seeks comments from the public that will refine analysis of areas planted in pineapple in the state 

of Hawaii.
48

9. References

Corwin D.L. and W.J Farmer. 1987. Nonsingle-Valued Adsorption-Desorption of Bromacil and 

Diquat by Freshwater Sediments. Environ. Sci. Technol., 18:7: 507-514.

Gerstl Z, Mingelgrin U. 1984. J Environ Sci Health B19: 297-312.

Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric 

Constants. Washington, D.C.: American Chemical Society. pg 61. 1995.

Hoffman, C.E. 1971. The Mode of Action of Bromacil and Related Uracils. IUPAC Congress of 

Pesticide Chemistry. Tel Aviv. Pesticide Chemistry Proceedings, 1972. Pp 65-85.

United States Department of Agriculture. 2010 (2006-2010). NASS Crop Reporting Districts. 

Online: 

http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass.

United States Department of Agriculture. 2007. Census of Agriculture. Online: 

http://www.agcensus.usda.gov/Publications/2007/index.asp.

United States Environmental Protection Agency. 1992. Memorandum from Dana Spatz 

(EFGWB/EFED) to Linda Propst (SRRD). Oct. 5, 1992. DP 182792.

United States Environmental Protection Agency. 1993. Memorandum from David Wells 

(EFGWB/EFED) to Linda Propst (SRRD), July 21, 1993. DP 191409, 191677.

United States Environmental Protection Agency. 1996. Reregistration Eligibility Decision on 

Bromacil. Office of Prevention, Pesticides, and Toxic Substances. Office of Pesticide 

Programs. Washington, D.C. August 1996.

United States Environmental Protection Agency. 1998. Guidelines for Ecological Risk 

Assessment. Risk Assessment Forum, Office of Research and Development,

Washington, D.C. EPA/630/R-95/002F. April 1998. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

United States Environmental Protection Agency. 2004. Overview of the Ecological Risk 

Assessment Process in the Office of Pesticide Programs. Office of Prevention, 

Pesticides, and Toxic Substances. Office of Pesticide Programs. Washington, D.C. 

January 23, 2004.

United States Environmental Protection Agency. 2007. Risks of Bromacil and Bromacil Lithium 

use to the Federally Listed California Red-legged Frog (Pesticide Effects Determination). 

Office of Prevention, Pesticides, and Toxic Substances. Office of Pesticide Programs. 

Washington, D.C. October 19, 2007.
49

United States Environmental Protection Agency. 2011. BEAD Chemical Profile for 

Registration Review: Bromacil (012301). Office of Chemical Safety and Pollution 

Prevention. Office of Pesticide Programs, Biological and Economical Analysis Division. 

Washington, D.C. December 5, 2011.

United States Environmental Protection Agency. 2012. BEAD Bromacil Usage Map by Crop 

Reporting District (012301). Office of Chemical Safety and Pollution Prevention. Office 

of Pesticide Programs, Biological and Economical Analysis Division. Washington, D.C. 

February 15, 2012.

United States Fish and Wildlife Service. 2011. Endangered species; Pacific Islands Fish and 

Wildlife Office. Webpage updated April 4, 2011; accessed on February 17, 2012.

http://www.fws.gov/pacificislands/species.html

United States Fish and Wildlife Service /National Marine Fisheries Service. 2004. 50 CFR Part 

402. Joint Counterpart Endangered Species Act Section 7 Consultation Regulations; 

Final Rule. FR 47732-47762.

Wolf DC, Martin JP. 1974. Soil Sci Amer Proc 38: 921-5.
50

Appendix A. Ecological Effects Data Summaries

Aquatic plant toxicity testing

OPPTS 850.5400

Selenastrum capricornutum was exposed to technical bromacil (96.5% ai) for 120 hours (MRID 

42516401; Supplemental). Initial-measured concentrations of bromacil were: <1.0 (control), 

1.10, 2.17, 4.38, 8.55, and 17.4 μg/L. Five-day inhibition (based on cell count) ranged from 15.2 

to 92.1%, yielding a five-day EC50 of 6.8 μg/L. A NOAEC was not established, and significant 

differences in cell count (as compared to the control) were determined at all concentrations using

Williams test.

OPPTS 850.5400

Navicula pelliculosa was exposed to technical bromacil (97.0% ai) for 120 hours (MRID 

44218501, Acceptable). Measured concentrations of bromacil were 0.403, 0.905, 1.88, 3.39, 

7.34, and 13.8 μg/L. Since no solvent was used, only a negative control was included in this test. 

The 120-hour EC50 was 6.91 μg ai/L, and the NOAEC was statistically established at 3.39 μg 

ai/L. The study personnel placed the algal cells exposed to the highest test concentration in fresh 

media following the five-day exposure and observed growth similar to that of the controls, 

indicating algistatic and not algicidal properties of bromacil.

OPPTS 850.5400

Anabaena flos-aquae was exposed to technical bromacil (97.0% ai) for 120 hours (MRID 

44218502, Acceptable). Measured concentrations of bromacil were 11.2 20.5, 42.7, 111, and 

188 μg ai/L. Since no solvent was used, only a negative control was included in this test. The 

120-hour EC50 was 69.9 μg ai/L, and the NOAEC was statistically established at 11.2 μg ai/L. 

Post-study experimentation with bromacil-exposed algae indicated compound algistatic, not 

algicidal, effects. 

OPPTS 850.5400

Skeletonema costatum was exposed to technical bromacil (97.0% ai) for 120 hours (MRID 

44218503, Acceptable). Measured concentrations of bromacil were 5.51, 11.5, 23.5, 44.8, and 

98.8 μg ai/L. Since no solvent was used, only a negative control was included in this test. The 

120-hour EC50 was 12.1 μg ai/L, and the NOAEC was statistically established at 5.5 μg ai/L. 

Seven days of post-study experimentation with bromacil-exposed algae indicated compound 

algistatic, not algicidal, effects. 

OPPTS 850.4400

Lemna gibba was exposed to technical bromacil (97.0% ai) for 14 days (MRID 46095401, 

Acceptable). Measured concentrations of bromacil were <1.13 (<LOQ; control), 17.0, 32.4, 

74.4, 157, 333, and 656 μg ai/L. Frond number and dry weight were similarly sensitive to 

treatment with bromacil. The NOAEC and EC50/IC50 values based on frond number were 17.0 

and 45 μg ai/L, respectively. The percent growth inhibition in the treated culture as compared to 

the control ranged from -1.6 to 98.4% based on frond number and from -7.7 to 98.8 based on dry 

weight. By test termination, chlorotic fronds were observed in the control and all treatment 

levels.
51

Freshwater fish and invertebrate acute toxicity

Two studies of acute effects of bromacil formulated product to rainbow trout (Oncorhynchus 

mykiss), and six studies of acute effects of bromacil formulated product to bluegill sunfish 

(Lepomis machrochirus) are characterized in Appendix A of the 2007 California Red-legged 

Frog Assessment (USEPA 2007). 

Additionally, one study conducted to determine the acute effects of bromacil formulated product 

(80% ai) to bluegill sunfish (Lepomis machrochirus) was not captured in Appendix A of the 

2007 assessment (MRID 00013297; Supplemental). The study author reported 24- and 48-hr 

LC50 values of 103 and 71 ppm, respectively.

OPPTS 850.1075

Acute effects of bromacil (96.6% ai) to rainbow trout (Oncorhynchus mykiss) were studied over 

a 96-hour static exposure (MRID 40951503; Acceptable). Rainbow trout were exposed to 

nominal concentrations of 0 (negative control), 16.9, 22.5, 30, 40, 53, 71, 95, 127, 169, and 225 

mg/L. The 96-hour LC50 was 36 mg/L; the NOAEC was 16.9 mg/L.

OPPTS 850.1075

Acute effects of bromacil (95% ai) to bluegill sunfish (Lepomis machrochirus) were studied over 

a 96-hour static exposure (MRID 40951502; Acceptable). Bluegill sunfish were exposed to 

nominal concentrations of 0 (negative control), 30, 40, 53, 71, 95, 127, 169, 225, and 300 mg/L. 

The 96-hour LC50 was 127 mg/L; the NOAEC was 71 mg/L.

OPPTS 850.1010

Acute effects of bromacil (96.6% ai) to Daphnia magna were studied over a 48-hour static 

exposure (MRID 40951504; Acceptable). Two replicates of 10 individuals were exposed to 

nominal concentrations of 0 (negative control), 11.2, 14.5, 20, 27, 35.5, 62.5, 83, 111, and 148 

mg/L. Total mortality was recorded for the highest dosage level of 148 mg/L; while the 111 

mg/L treatment only had 20% mortality in one replicate. The EC50 was 121 mg/L; the NOAEC 

was 83 mg/L.

Estuarine/Marine fish and invertebrates

OPPTS 850.1075

Acute effects of bromacil (95.1% ai) to Cyprinodon variegatus were studied over a 96-hour 

semi-static exposure (MRID 41588702; Acceptable). C. variegatus were exposed to meanmeasured concentrations of 37.6, 55.1, 95.6, 145.8, and 272 mg ai/L. A negative control was 

used, and no solvents were employed. The 96-hour LC50 was 162.8 mg ai/L; the NOAEC was 

55.1 mg ai/L.

OPPTS 850.1035
52

Acute effects of bromacil (95.1% ai) to Americamysis bahia were studied over a 96-hour static 

exposure (MRID 41588701; Acceptable). A. bahia were exposed to mean-measured 

concentrations of 25.7, 42, 67.0, 104.4, and 148 mg ai/L. A negative control was used, and no 

solvents were employed. The 96-hour LC50 was 112.9 ppm; the NOAEC was 67 ppm.

OPPTS 850.1035

Acute effects of bromacil (95% ai) to Americamysis bahia were studied over a 96-hour static 

exposure (MRID 00126346; Supplemental). A. bahia were exposed to nominal concentrations 

of 62, 125, 250, 500, and 1,000 μg/L. The 96-hour LC50 was estimated to be >1,000 μg/L.

OPPTS 850.1055

Acute effects of bromacil (95.1% ai) to Crassostrea virginica were studied over a 48-hour static 

exposure (MRID 41588703; Supplemental). C. virginica were exposed to measured

concentrations of 26, 41, 62, 100, and 150 mg/L. A negative control was employed. The 48-

hour EC50, based on percentage reduction of normal oyster larvae, was 130 mg ai/L; the NOAEC 

could not be established because of poor control performance.

Non-guideline

Juvenile individuals of the following species were tested by the EPA ORD Environmental 

Research Laboratory at Gulf Breeze, FL: brown shrimp (Penaeus aztecus), eastern oyster 

(Crassostrea virginica), and spot (Leiostomus xanthurus) (MRID 40228401; Supplemental). 

Technical Bromacil (95% ai) was diluted in exposure water at concentrations up to 1,000 μg/L. 

The 48-hour EC50 for brown shrimp and spot, and 96-hour EC50 for eastern oyster, were 

estimated to be >1.0 ppm. 

Fish and invertebrate chronic toxicity

OPPTS 850.1400

The 90-day chronic toxicity of DPX-N976 Technical (bromacil, 98.07% ai) to the early life stage 

of rainbow trout (Oncorhynchus mykiss) was studied under flow-through conditions (MRID 

44566101; Supplemental). Fertilized eggs/embryos (80/level, 22 hours post-fertilization) of 

rainbow trout were exposed to nominal concentrations of 0 (negative and solvent controls), 0.06, 

0.12, 0.24, 0.48, 0.96, 2.4, and 6.0 mg/L. TWA concentrations (reviewer-calculated) were 

<0.0004 (<LOD, controls), 0.070, 0.15, 0.29, 0.60, 1.2, 3.0, and 7.2 mg ai/L, respectively. The 

NOAEC and LOAEC values for this study were 3.0 and 7.2 mg ai/L, respectively, based on 

treatment-related effects on mean wet weight (the only endpoint affected).

OPPTS 850.1300

The 21-day-chronic toxicity of DPX-N976 Technical (bromacil, 98.07% ai) to Daphnia magna

was studied under static renewal conditions (MRID 44566401; Acceptable). Daphnids were 

exposed to DPX-N976 Technical at mean-measured concentrations of <0.00040 (<LOD, 

control), 0.10, 0.21, 0.45, 0.88, 1.7, 3.4, 8.2, and 21 mg ai/L, respectively. The number of live 

neonates per adult, mean terminal length, and mean terminal dry weight were the most sensitive 

endpoints, with significant reductions at the 21 mg ai/L treatment level. Based on these effects, 

the 21-day NOAEC and LOAEC were 8.2 and 21 mg ai/L, respectively. There were no 
53

treatment-related effects on survival, reproduction, or growth of Daphnia magna exposed to 

DPX-N976 at concentrations up through 8.2 mg ai/L for 21 days. At test termination, all 

surviving adult daphnids exposed appeared normal without ephippia. Daphnids exposed to 21 

mg ai/L did not produce any neonates and had significantly reduced lengths (13% inhibition) and 

dry weights (45% inhibition) in comparison to the negative control. 

Avian toxicity studies

OPPTS 850.2100

Technical bromacil (96.6% ai) was administered to 21-week old bobwhite quail at nominal doses 

of 292, 486, 810, 1350, and 2250 mg/kg-bw (MRID 40951501; Acceptable). Corn oil was used 

as the test diet vehicle and dosages were adjusted upward to correct to 100% active ingredient. 

The acute oral LD50 was determined to be >2250 mg/kg-bw and the NOAEC was 810 mg/kgbw, based on reductions in female body weight gain at 1350 mg/kg-bw.

OPPTS 850.2100

The lithium salt of bromacil was administered to four-to-six day old bobwhite quail chicks over 

7 days at nominal doses of 0 (control), 200, 300, 350, 400, 450, and 500 mL/kg. The LD50 was 

determined to be 355 mL/kg. The NOAEC was established at 200 mL/kg, based on slight 

depression following dosing at 300 mL/kg.

OPPTS 850.2200

Bromacil (80% ai) was fed to one-week old mallard ducks at nominal doses of 0, 464, 1000, 

2150, 4640, and 10,000 ppm, and to one-week old bobwhite quail at nominal doses of 0, 215, 

464, 1000, 2150, 4640, and 10,000 ppm for five days (MRID 00013295; Acceptable). No 

mortalities were observed in exposures involving mallard ducks. Bobwhite quail mortalities 

were observed in exposures involving several different treatment levels; however, the mortalities 

were less than 50% of individuals in each treatment group. In the test, 6.8% mortality was 

observed in controls, 10% mortality was observed in the 464 and 4,640 mg/kg-diet/day treatment 

levels and 20% mortality was observed in the 2,150 and 10,000 mg/kg-diet/day treatment levels. 

The eight-day LC50 was determined to be >10,000 ppm. This study is classified acceptable for a 

formulated product, but supplemental for use in risk assessment, since the test material was not 

technical bromacil as required by 40 CFR §158.630.

OPPTS 850.2200

Bromacil (80% ai) was fed to mallard ducks and bobwhite quail at nominal doses up to 10,000 

ppm (MRID 00013296; Acceptable). No toxic effects were recorded. The eight-day LC50 was 

determined to be >10,000 ppm.

OPPTS 850.2300

Technical bromacil (98.07% ai) was fed to 18-week old mallard duck for 22 weeks at nominal 

concentrations of 775, 1550, 3100, and 6200 ppm (MRID 44844601; Acceptable). There were 

statistically significant treatment-related effects to hatchability at the 3100 ppm ai treatment 

level. The NOAEC and LOAEC were determined to be 1550 and 3100 ppm, respectively.
54

OPPTS 850.2300

Technical bromacil (98.07% ai) was fed to 18-week old bobwhite quail for 21 weeks at nominal 

concentrations of 775, 1550, 3100, and 6200 ppm (MRID 44844801; Acceptable). There were 

statistically significant treatment-related effects to hatchability at the 3100 ppm ai treatment 

level. The NOAEC and LOAEC were determined to be 1550 and 3100 ppm, respectively.

Terrestrial invertebrate studies

OPPTS 850.3020

Acute laboratory comparative tests were performed with more than 50 chemicals, including 

bromacil (Hyvar®-X, purity not reported) (MRID 00009181; Supplemental). The material was 

mixed with non-toxic diluent dust and applied directly to bees in a vacuum dusting apparatus. 

Mortality was evaluated 48 hours after application. The LD50 was reported to be 193.38 μg per 

bee, and bromacil is classified as practically nontoxic to honey bees.

OPPTS 850.3020

Acute laboratory comparative tests were performed with 197 chemicals, including bromacil 

(Hyvar®, purity not reported) (MRID 00132710; Supplemental). The material was mixed with 

non-toxic diluent dust and applied directly to bees in a vacuum dusting apparatus at 

concentrations up to 11 μg per bee. Mortality was evaluated 48 hours after application. The 

LD50 level was not attained, and bromacil is classified as practically nontoxic to honey bees.

Non-guideline toxicity to insect parasite

The toxicity of bromacil (80% ai) to juvenile Aphytis melinus and virgin 3rd instar red scale, was 

studied four days after treatment, and to emerging adult A. melinus 14-27 days after treatment 

(MRID 05004003; Supplemental). Bromacil was applied at 4,000 ppm. 97.5% of juvenile A. 

melinus were alive at four days after treatment. Of the 41 adults that emerged, 7 were active at 

day 27, and toxicity was qualitatively rated as “moderate.”

Terrestrial Plant Studies

OPPTS 850.4225 

A 14-day terrestrial plant: seedling emergence (MRID 42491101; Supplemental10) was 

conducted for bromacil (95.9% ai). Species tested; monocots: corn, onion, sorghum, and wheat; 

dicots: cucumber, pea, rape, soybean, sugarbeet11, and tomato. Nominal application rates were: 

0.00586, 0.0117, 0.0234, 0.0469, and 0.0938 lb ai/A (onion, sugarbeet, tomato, rape, cucumber); 

0.0938, 0.188, 0.375, 0.750, and 1.50 lbs ai/A (corn); 0.0234, 0.0469, 0.0938, 0.188, and 0.375 

lb ai/A (wheat, sorghum, soybean); and 0.0234, 0.0938, 0.375, 1.50, and 6.00 lbs ai/A (pea). The 

most sensitive dicot was rape with NOAEC and EC25

 10 Although data for nine plant species were acceptable, this study was classified as supplemental overall because 

data for sugarbeet were unacceptable.

values for shoot height of 0.0117 and 

0.0136 lb ai/A, respectively. Statistical analysis to determine the most sensitive monocot was 

11 The results of testing with sugarbeet were not considered scientifically sound and were classified as unacceptable 

because of seed treatment with unapproved chemicals (i.e., chlorneb, lindane, and dexon).
55

not performed; however, the study authors’ analysis indicates that wheat was the most sensitive, 

with shoot height NOAEC and EC25 values of 0.0234 and 0.0731 lb ai/A.

OPPTS 850.4250

A 21-day terrestrial plant: vegetative vigor (MRID 42491101; Supplemental10) was conducted 

for bromacil (95.9% ai). Species tested; monocots: corn, onion, sorghum, and wheat; dicots: 

cucumber, pea, rape, soybean, sugarbeet11, and tomato. Nominal rates of 0.00586, 0.0117, 

0.0234, 0.0469, and 0.0938 lb ai/A were applied to onion, wheat, sugarbeet, soybean, tomato, 

rape, and cucumber; and nominal rates of 0.0234, 0.0469, 0.0938, 0.188, and 0.375 lb ai/A were 

applied to corn, sorghum, and pea. The results from rape were scientifically sound but did not 

meet the guideline requirement for a tier II vegetative vigor study because a NOAEC was not 

determined for the most sensitive endpoint: root weight. The most sensitive dicot was rape, with 

an EC25 for root weight of 0.0023 lb ai/A. Statistical analysis to determine the most sensitive 

monocot was not performed; however, the study authors’ analysis indicates that wheat was the 

most sensitive, with shoot weight NOAEC and EC25 values of 0.0469 and 0.0684 lb ai/A.

OPPTS 850.4225 

A 14-day terrestrial plant: seedling emergence (MRID 44488307; Supplemental, nonguideline12) was conducted for bromacil (98.07% ai). Nominal rates of 0 (negative and carrier 

controls), 0.003, 0.006, 0.01, 0.02, 0.04, 0.09, and 0.2 lb ai/A were applied to wheat, while 

nominal rates of 0 (negative and carrier controls), 0.001, 0.003, 0.006, 0.01, 0.02, 0.04, and 0.09 

lb ai/A were applied to rape. The most sensitive endpoint for monocot wheat was dry weight 

with NOAEC and EC25 values of 0.02 and 0.030 lb ai/A, respectively. The most sensitive 

endpoint for dicot rape was also dry weight, with NOAEC and EC25 values of 0.0011 and 0.0047

lb ai/A. The following abnormalities were noted: slight growth retardation, malformations, 

chlorosis, and necrosis.

OPPTS 850.4225 

A 14-day terrestrial plant: seedling emergence (MRID 44488307; Supplemental, nonguideline12) was conducted for the lithium salt of bromacil (86.07% ai). Nominal rates of 0 

(negative and carrier controls), 0.003, 0.006, 0.01, 0.02, 0.04, 0.09, and 0.2 lb ai/A were applied 

to wheat, while nominal rates of 0 (negative and carrier controls), 0.001, 0.003, 0.006, 0.01, 0.02, 

0.04, and 0.09 lb ai/A were applied to rape. The most sensitive endpoint for monocot wheat was 

dry weight with NOAEC and EC25 values of 0.02 and 0.034 lb ai/A, respectively. The most 

sensitive endpoint for dicot rape was also dry weight, with NOAEC and EC25 values of 0.006 

and 0.010 lb ai/A. The following abnormalities were noted: slight to moderate chlorosis, slight 

to severe growth retardation, slight unusual pigmentation, and slight to severe burns or necrosis.

OPPTS 850.4250

The effect of bromacil (98.07% ai) on the vegetative vigor of monocot (wheat) and dicot (rape) 

were studied at nominal application rates of 0 (negative and carrier controls), 0.0007, 0.001, 

0.003, 0.006, 0.01, 0.02, 0.04, 0.09, 0.2, and 0.4 lb ai/A over 21-days (MRID 44488307; 

 12 This study is classified as non-guideline because it does not contain information for all 10 required test species of 

plants. Instead, this study was intended to create suitable data for comparison of the effects of bromacil and 

bromacil lithium on seedling emergence and vegetative vigor. This study is useful for comparing the toxicities of 

the two chemicals to terrestrial plants.
56

Supplemental, non-guideline12). The most sensitive endpoint for wheat was dry weight with 

NOAEC and EC25 values of 0.02 and 0.042 lb ai/A, respectively. The most sensitive endpoint

for rape was also dry weight, with NOAEC and EC25 values of 0.003 and 0.0055 lb ai/A. The 

following abnormalities were noted: chlorosis, necrosis, and growth retardation.

OPPTS 850.4250

The effect of the lithium salt of bromacil (86.07% ai) on the vegetative vigor of monocot (wheat) 

and dicot (rape) were studied at nominal application rates of 0 (negative and carrier controls), 

0.0007, 0.001, 0.003, 0.006, 0.01, 0.02, 0.04, 0.09, 0.2, and 0.4 lb ai/A over 21-days (MRID 

44488307; Supplemental, non-guideline12). The most sensitive endpoint for wheat was dry 

weight with NOAEC and EC25 values of 0.001 and 0.028 lb ai/A, respectively. The most 

sensitive endpoint for rape was also dry weight, with NOAEC and EC25 values of 0.006 and 

0.0060 lb ai/A. The following abnormalities were noted: chlorosis, necrosis, and growth 

retardation.

Bromacil seedling emergence

Species Endpoint NOAEC EC25 EC50

Wheat Dry Weight 0.02 0.030 0.085

Wheat Height 0.04 0.080 0.22

Rape Dry Weight 0.0011* 0.0047 0.013

Rape Height 0.01 0.018 0.17

Bromacil lithium salt seedling emergence

Species Endpoint NOAEC EC25 EC50

Wheat Dry Weight 0.02 0.034 0.087

Wheat Height 0.04** 0.091 0.23

Rape Dry Weight 0.006 0.010 0.013

Rape Height 0.01 0.018 0.028

Bromacil vegetative vigor

Species Endpoint NOAEC EC25 EC50

Wheat Dry Weight 0.02 0.042 0.068

Wheat Height 0.04** 0.23 0.55

Rape Dry Weight 0.003 0.0055 0.010

Rape Height 0.01** 0.025 0.063

Bromacil lithium salt vegetative vigor

Species Endpoint NOAEC EC25 EC50

Wheat Dry Weight 0.001 0.028 0.065

Wheat Height 0.04 0.34 0.87

Rape Dry Weight 0.003** 0.0060 0.010

Rape Height 0.01** 0.024 0.034

*The EC05

**NOAEC visually determined

is used in lieu of the NOAEC
57

Appendix B. Fate and Ecological Effects Bibliographies

Environmental Fate and Transport Bibliography

MRID/PDF/Ecotox Citation Reference

40951505 Das, Y. (1988) Hydrolysis of ?2-?carbon 14||Bromacil in Aqueous Solutions Buffered at pH 

5,7, and 9: Project No. 86001-02; Du Pont Document No. AMR-522-86. Unpublished study 

prepared by Biospherics Inc. 33 p. 

40951506 Dulka, J.; Ryan, T. (1988) Hydrolysis of ?2-?carbon 14||Bromacil in Aqueous Solution 

Buffered at pH 9: Project ID: AMR-902-87. Un- published study prepared by E.I. du Pont de 

Nemours and Co., Inc. 22 p. 

161-2 Photodegradation-water

MRID Citation Reference

40951507 Das, Y. (1986) Photodegradation of ?2-?carbon 14||Bromacil in Aqueous Solutions Buffered at 

pH 5, 7, and 9: Project No. 86001- 01; Study No. AMR-523-86. Unpublished study prepared by 

Bio- spherics Inc. 65 p. 

40951508 Dulka, J.; Ryan, T. (1988) Photodegradation of ?2-?carbon 14||Bro- macil in Water at pH 9: 

Project ID: AMR-901-87. Unpublished study prepared by E.I. du Pont de Nemours and Co., Inc. 

28 p. 

00126338 Chrzanowski, R. (1981?) Photodegradation of Bromacil in Water: Doc- ument No. AMR-78-82. 

(Unpublished study received Mar 10, 1983 under 352-325; submitted by E.I. du Pont de 

Nemours & Co., Inc., Wilmington, DE; CDL:249679-C)

5018069 Archer, A.J. and E. Dunkelblum. 1979. Identification of sensitized photooxidation products of 

bromacil in water. J. Agric. Food Chem. 27(6):1184-1187.

161-3 Photodegradation-soil

MRID Citation Reference

40951509 Das, Y. (1988) Photodegradation of ?2-?carbon 14||Bromacil on Soil Under Artificial Sunlight: 

Project No. 86001-03; Du Pont Docu- ment No. AMR-558-86. Unpublished study prepared by 

Biospheric Inc. 46 p. 

162-1 Aerobic soil metabolism

MRID Citation Reference

40951510 Vigon, B.; Arthur, M. (1988) Aerobic Soil Metabolism of ?2-?carbon 14||Bromacil in Stine 

Farm, DE, Silty Clay Loam: Project ID: N0766-7300; Du Pont Report No. AMR-500-86. 

Unpublished study prepared by Battelle Columbus Div. 50 p. 
58

162-3 Anaerobic aquatic metab.

MRID Citation Reference

40951511 Vigon, B.; Arthur, M. (1988) Anaerobic Aquatic Metabolism of ?2- ?carbon 14||Bromacil in 

West Jefferson, OH Pond Sediment and Water: Project ID: N0766-7300. Unpublished study 

prepared by Battelle Columbus Div. 57 p. 

163-1 Leach/adsorp/desorption

MRID Citation Reference

40951512 Voudrias, E. (1988) Soil-Column Leaching of ?2-?carbon 14||Broma- cil: Project ID: 

Battelle Project No. N0799-8700; Du Pont Report No. AMR-645-86. Unpublished 

study prepared by Battelle Columbus Div. 54 p. 

164-1 Terrestrial field dissipation

MRID Citation Reference

41677101 Schneiders, G. (1990) Field Soil Dissipation of Hyvar X Herbicide: Lab Project Number: 

AMR/1146/88. Unpublished study prepared by E. I. du Pont de Nemours and Co. 64 p. 

165-4 Bioaccumulation in fish

MRID Citation Reference

40951513 Hutton, D. (1986) ?2-?carbon 14|| Bromacil Bioconcentration in Bluegill Sunfish: Du Pont HLR 

378-86; AMR-494-86. Unpublished study prepared by E.I. du Pont de Nemours and Co., Inc. 49 

p.

166-1 Ground water-small prospective

MRID Citation Reference

44480701 Peter, C.; Carver, L.; Johnson, L. et al. (1998) Small-Scale Prospective Ground-Water 

Monitoring Study for Bromacil (DPX-N976): Final Report: Lab Project Number: AMR 2931-

94: 387.10: AMR-633-86. Unpublished study prepared by Waterborne Environmental, Inc.;

Florida Pesticide Research, Inc.; Murray Consultants, Inc. 692 p. 

Ecological Effects Bibliography

71-1 Avian Single Dose Oral Toxicity
59

MRID PDF # Citation Reference

13295 Dieterich, W.H. (1965) Acute Oral Toxicity--Mallard Ducks, Bobwhite Quail: Project 

No. 201-154. (Unpublished study received Nov 22, 1965 under 352-287; prepared by 

Hazleton Laboratories, Inc., submitted by E.I. du Pont de Nemours & Co., Wilmington, 

Del.; CDL:100405-A) 

40951501 2025321 Grimes, J. (1986) H-16287: An Acute Oral Toxicity Study with the Bobwhite: Final 

Report: Wildlife International Ltd., Project No. 112-173. Unpublished study prepared by 

Wildlife International Ltd. 18 p. 

71-2 Avian Dietary

MRID PDF # Citation Reference

13295 or 13296 2025298 E.I. du Pont de Nemours & Company (1970) Toxicological Information: Hyvar X 

Bromacil Weed Killer--Fish and Wildlife. (Unpublished study received on unknown date 

under 352-287; CDL:100850-A) 

71-4 Avian Reproduction

MRID PDF # Citation Reference

44844601 2025332 Gallagher, S.; Beavers, J.; Jaber, M. (1999) DPX-N976 Technical: A Reproduction 

Study with the Mallard (Anas platyrhynchos): Lab Project Number: AMR 4832-97: 

112-477. Unpublished study prepared by Wildlife International Ltd. 186 p. 

44844801 2025331 Gallagher, S.; Beavers, J.; Jaber, M. (1999) DPX-N976 Technical: A Reproduction 

Study with the Northern Bobwhite (Colinus virginianus): Lab Project Number: AMR4831-97: 112-476. Unpublished study prepared by Wildlife International Ltd. 187 p. 

72-1 Acute Toxicity to Freshwater Fish

MRID PDF# Citation Reference

13378 Rausina, G. (1976) Report to Nalco Chemical Company: Four-Day Static Aquatic 

Toxicity Studies with BX-933 in Rainbow Trout, Bluegills and Daphnia: IBT No. 

8560-08684. (Unpublished study including letter dated Nov 2, 1977 from C.H. Wolf to 

Environmental Protection Agency, received Nov 9, 1977 under 1706-107; prepared by 

Industrial Bio-Test Laboratories, Inc., submitted by Nalco Chemical Co., Oak Brook, 

Ill.; CDL:232181-A) 

13297 2025300 E.I. du Pont de Nemours and Company (1964) Hyvar X Bromacil Weed Killer: Acute

Toxicity--Fish. (Unpublished study received on unknown date under 352-287; 

CDL:100850-B)

111458 Bond, C.; Wilson, D.; Malick, J. (1967) Progress Report on Aquatic Weed Research 

(Project 773). (Unpublished study received Jun 28, 1979 under 0F0863; prepared by 

Oregon State Univ., Agricul- tural Experiment Station, Dept. of Fisheries and Wildlife, 

sub- mitted by Dow Chemical Co., Indianapolis, IN; CDL:098349-I) 

126344 Call, D.; Kent, R.; Brooke, L. (1979) Estimates of No Effect Con- centrations of 

Selected Pesticides in Freshwater Organisms: U.S. EPA Grant No. R-806196-01. 3rd 
60

quarterly progress rept. Jan 1-Mar 31, 1979. (Unpublished study received Mar 10, 

1983 under 352-325; prepared by Univ. of Wisconsin, submitted by E.I. du Pont de 

Nemours & Co., Inc., Wilmington, DE; CDL:249679-J) 

126345 2025310 Yoshida, K.; Nishiuchi, Y. (1972) Toxicity of Pesticides to Some Water Organisms. 

(Unpublished study received Mar 10, 1983 under 352-325; submitted by E.I. du Pont 

de Nemours & Co., Inc., Wil- mington, DE; CDL:249679-K) 

141633 2025227 Call, D.; Brooke, L.; Kent, R. (1983) Toxicity, bioconcentration, and metabolism of 

five herbicides in freshwater fish. Prepared by Univ. of Wisconsin, Center for Lake 

Superior Environmental Studies for the Environmental Protection Agency; available 

from the National Technical Information Service. 113 p. 

141636 Call, D.; Brooke, L.; Kent, R. (1983) Toxicity, bioconcentration, and metabolism of 

five herbicides in freshwater fish. Prepared by Univ. of Wisconsin, Center for Lake 

Superior Environmental studies for the Environmental Protection Agency; available 

from the National Technical Information Service. 113 p. 

40951502 2025322 Hutton, D. (1988) Static Acute 96-Hour LC50a of Bromacil to the Bluegill Sunfish 

(Lepomis macrochirus): Haskell Laboratory Report No. 163-83; MR No. 7708-001. 

Unpublished study prepared by E.I. du Pont de Nemours and Co., Inc. 10 p. 

40951503 2025323 Hutton, D. (1988) Static Acute 96-Hour LC50a of Bromacil to Rainbow Trout (Salmo 

gairdneri): Haskell Laboratory Report No. 265-86; MR No. 4581-373. Unpublished 

study prepared by E.I. du Pont de Nemours and Co., Inc. 10 p. 

24960 2025302 

TN353

McCann, J.A. (1971) ?Hyvar X: Toxicity to Bluegill|: Test No. 353. (U.S. Agricultural 

Research Service, Pesticides Regulation Div., Animal Biology Laboratory, 

unpublished report.) 

24961 2025303 

TN610

Pitcher, F.G. (1973) ?Mister Zero: Toxicity to Bluegill|: Test No. 610. (U.S. 

Environmental Protection Agency, Pesticides Reg- ulation Div., Agricultural Research 

Center, Animal Biology Labo- ratory, unpublished report.) 

24962 2025304 

TN626

Pitcher, F.G. (1973) ?Atlas 603 Ded-Veg: Toxicity to Bluegill|: Test No. 626. (U.S. 

Environmental Protection Agency, Pesticides Regulation Div., Agricultural Research 

Center, Animal Biology Laboratory, unpublished report.) 

24964/ 2025305 

TN 457

McCann, J.A. (1972) (Ureabor: Toxicity to Rainbow Trout): Test No. 457. (U.S. 

Agricultural Research Service, Pesticides Regu- lation Div., Animal Biology 

Laboratory, unpublished report.) 

24965 2025306 

TN447

McCann, J.A. (1972) (Ureabor: Toxicity to Bluegill): Test No. 447. (U.S. Agricultural 

Research Service, Pesticides Regulation Div., Animal Biology Laboratory, 

unpublished report.) 

Mixture with Na Metaborate and Na chloate

24967 2025307 

TN773

Pitcher, F.G. (1974) ?Weedgard G: Toxicity to Rainbow Trout|: Test No. 773. (U.S. 

Environmental Protection Agency, Chemical & Biological Investigations Branch, 

TSD, Animal Biology Laborato- ry, unpublished report.) 

24968 2025308 

TN608

Pitcher, F.G. (1973) ?UL-85: Toxicity to Bluegill|: Test No. 608. (U.S. 

Environmental Protection Agency, Pesticides Regulation Div., Agricultural Research 

Center, Animal Biology Laboratory, unpublished report.) 

24969 2025309 

TN 643

Pitcher, F.G. (1973) ?Weedgard G: Toxicity to Bluegill|: Test No. 643. (U.S. 

Environmental Protection Agency, Pesticides Reg- ulation Div., Agricultural Research 

Center, Animal Biology Labo- ratory, unpublished report.) 
61

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

126345 2025318

2025315

Yoshida, K.; Nishiuchi, Y. (1972) Toxicity of Pesticides to Some Water Organisms. 

(Unpublished study received Mar 10, 1983 under 352-325; submitted by E.I. du 

Pont de Nemours & Co., Inc., Wil- mington, DE; CDL:249679-K) 

40951504 2025324 Hutton, D. (1986) Daphnia magna Static Acute 48-Hour EC50 of Bromo- cil: 

Project ID: HLR 341-86. Unpublished study prepared by E.I. du Pont de Nemours 

and Co., Inc. 10 p. 

13378 Rausina, G. (1976) Report to Nalco Chemical Company: Four-Day Static Aquatic 

Toxicity Studies with BX-933 in Rainbow Trout, Bluegills and Daphnia: IBT No. 

8560-08684. (Unpublished study including letter dated Nov 2, 1977 from C.H. 

Wolf to Environmental Protection Agency, received Nov 9, 1977 under 1706-107; 

prepared by Industrial Bio-Test Laboratories, Inc., submitted by Nalco Chemical 

Co., Oak Brook, Ill.; CDL:232181-A) 

72-3 Acute Toxicity to Estuarine/Marine Organisms

MRID Citation Reference

126346// 2025316

2025311

Hollister, T. (1980) Acute Toxicity of Fifteen Chemicals to Mysid Shrimp ...: 

Report No. BP-80-2-43. (Unpublished study received Mar 10, 1983 under 352-

325; prepared by EG & G, Bionomics, sub- mitted by E.I. du Pont de Nemours 

& Co., Inc., Wilmington, DE; CDL:249679-L) 

41588701 2025325 Boeri, R. (1989) Static Acute Toxicity of Bromacil to the Mysid, Mysidopsis 

bahia: Lab Project Number: DP2788. Unpublished study prepared by Enseco 

Inc. 21 p. 

41588702 2025326 Boeri, R. (1989) Static Acute Toxicity of Bromacil to the Sheep- shead 

Minnow, Cyprinodon variegatus: Lab Project Number: DP2888. Unpublished 

study prepared by Enseco Inc. 21 p. 

41588703 2025327 Boeri, R. (1989) Static Acute Toxicity of Bromacil to Embryos and Larvae of 

the Eastern Oyster Crassostrea virginica: Lab Project Number: DP2988. 

Unpublished study prepared by Enseco Inc., 21 p. 

41896101 Wrong 

Chemical

Ward, T.; Boeri, R. (1991) Static Acute Toxicity of Terbacil to the 

Sheepshead Minnow, Cyprinodon variegatus: Lab Project Number: 4581-806. 

Unpublished study prepared by Envirosystems/Resource Analysts Inc. 31 p. 

ACC 249679 2025310 Yoshida, K. 1970. Toxicity of Pesticide to Killifish. 

40228401 2025320 Mayer, F.L. 1986 EPA /600/x-86/231 Acute Toxicity Handbook of 

Chemicals to Estuarine Organisms

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID PDF # Citation Reference

44566101 2066664 Hoke, R. (1998) DPX-N976 Technical: Early Life-Stage Toxicity to Rainbow 
62

Trout (Oncorhynchus mykiss): Lab Project Number: HL-1998-01349: 11691. 

Unpublished study prepared by E.I. du Pont de Nemours and Company. 148 p. 

44566401 2066665 Drottar, K.; Krueger, H. (1998) DPX-N976 Technical: A Semi-Static LifeCycle Toxicity Test with the Cladoceran (Daphnia magna): Final Report: Lab 

Project Number: 112A-172: 1998-01475. Unpublished study prepared by 

Wildlife International Ltd. 73 p. 

72-5 Life cycle fish (OPPIN incorrectly placed these under 72-5)

MRID Citation Reference

141633 or 

141636

DER not located Call, D.; Brooke, L.; Kent, R. (1983) Toxicity, bioconcentration, and 

metabolism of five herbicides in freshwater fish. Prepared by Univ. of 

Wisconsin, Center for Lake Superior Environmental Studies for the 

Environmental Protection Agency; available from the National Technical 

Information Service. 113 p. 

122-1 Seed Germination/Seedline Emergence and Vegetative Vigor

MRID PDF/ Citation Reference

42491101 2025328 Carski, T. (1992) Influence of Bromacil on Seed Germination, Seedling 

Emergence, and Vegetative Vigor of Several Terrestrial Plants: Lab Project 

Number: AMR 2304-92. Unpublished study prepared by Dupont Haskell Labs. 237 

p. 

44036501 2025339 Heldreth, K. (1993) Impact of An Acetone Control on Seed Germination of Several 

Terrestrial Plant Species: Lab Project Number: AMR 2624-93. Unpublished study 

prepared by Stine-Haskell Research Center, DuPont Agricultural Products. 22 p. 

44036502 2025339 Heldreth, K. (1993) Impact of An Acetone Control on Seedling Emergence and 

Elongation of Several Terrestrial Plant Species: Lab Project Number: AMR 2688-

93. Unpublished study prepared by Stine-Haskell Research Center, DuPont 

Agricultural Products. 24 p. 

44036503 2025339 Heldreth, K. (1993) Impact of An Acetone Control on Vegetative Vigor of Several 

Terrestrial Plant Species: Lab Project Number: AMR 2720-93. Unpublished study 

prepared by Stine-Haskell Research Center, DuPont Agricultural Products. 28 p. 

123-1 Seed germination/seedling emergence and vegetative vigor

MRID Citation Reference

42491101 2025328 Carski, T. (1992) Influence of Bromacil on Seed Germination, Seedling Emergence, 

and Vegetative Vigor of Several Terrestrial Plants: Lab Project Number: AMR 

2304-92. Unpublished study prepared by Dupont Haskell Labs. 237 p. 

44488307 2066670 - SE

20666671 –

VVg

2066672= 

lithium salt

2066673 = 

Heldreth, K.; McKelvey, R. (1997) Influence of Bromacil on Seed Germination, 

Seedling Emergence, and Vegetative Vigor of Several Terrestrial Plants: 

Supplement No. 1: Lab Project Number: MR 11430: AMR 2304-92. Unpublished 

study prepared by DuPont Stine-Haskell Research Center and Haskell Laboratory 

for Toxicology and Industrial Medicine. 209 p. 
63

lithium salt

123-2 Aquatic plant growth

MRID Citation Reference

42516401 2025329 Hughes, J.; Williams, T. (1992) Bromacil: Toxicity to Selenastrum capriconutum: Lab 

Project Number: B382-156-1: AMR 2402-92. Unpublished study prepared by 

Malcolm Pinie Inc. 27 p. 

44218501 2066666 Hughes, J.; Alexander, M.; Conder, L. (1997) Bromacil: Influence on Growth and 

Reproduction of Navicula pelliculosa: Lab Project Number: AMR 3799-96: 19-05-2. 

Unpublished study prepared by Carolina Ecotox, Inc. 84 p. Relates to L0000187.

44218502 2066667 Hughes, J.; Alexander, M.; Conder, L. (1997) Bromacil: Influence on Growth and 

Reproduction of Anabaena flos-aquae: Lab Project Number: AMR 3800-96: 19-05-1. 

Unpublished study prepared by Carolina Ecotox, Inc. 83 p. Relates to L0000187.

44218503 2066668 Hughes, J.; Alexander, M.; Conder, L. (1997) Bromacil: Influence on Growth and 

Reproduction of Skeletonema costatum: Lab Project Number: 19-05-3: AMR 3801-96. 

Unpublished study prepared by Carolina Ecotox, Inc. 86 p. Relates to L0000187. 

44300901 Hughes, J.; Alexander, M.; Conder, L. (1997) Bromacil: Influence on Growth and 

Reproduction of Lemna gibba: (Revision 1): Lab Project Number: AMR 3990-96: 19-

05-4. Unpublished study prepared by Carolina Ecotox, Inc. 74 p. 

46095401 2066669 Hughes, J.; Alexander, M.; Conder, L. (1997) Bromacil: Influence on Growth and 

Reproduction of Lemna gibba. Project Number: 19/05/4, AMR/3990/96. Unpublished 

study prepared by Carolina Ecotox, Inc. 74 p.

5014904 2025263 Citation for this MRID not found in OPPIN

141-1 Honeybee toxicity

MRID PDF # Citation Reference

132710

ACC251374

2025319 Atkins, E.; Anderson, L.; Kellum, D.; et al. (1977) Protecting Hon- ey Bees from 

Pesticides. Riverside, CA: Univ. of California. (Leaflet 2883; also In unpublished 

submission received Nov 2, 1983 under 239-2507; submitted by Chevron 

Chemical Co., Rich- mond, CA; CDL:251760-B)

9181 2025297 Atkins, E.L., Jr.; Anderson, L.D.; Greywood, E.A. (1969) Effect of Pesticides on 

Apiculture: Project No. 1499. (Unpublished study received Jul 29, 1976 under 

352-342; prepared by Univ. of Cali- fornia--Riverside, Dept. of Entomology, 

submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:224800-C)

18842 2025301 Same as 9181

142-3 Simulated or Actual Field Testing

MRID Citation Reference

60632 No DER 

found

Johansen, C.; Eves, J. (1967) Bee Research Investigations, 1967: Report No. 21866. 

(Unpublished study received Mar 27, 1974 un- der 4F1485; prepared by Washington State 

Univ., submitted by Chemagro Corp., Kansas City, Mo.; CDL:092011-M) 
64

NON Guideline

5004003 2025312 Citation for this MRID not found in OPPIN

5019478 2025313 Citation for this MRID not found in OPPIN

5020972 2025314 Citation for this MRID not found in OPPIN

5014916 2025265 Citation for this MRID not found in OPPIN

41145 Bond, C.E.; Wilson, D.C.; Malick, J. (1967) Aquatic Weed Control Progress Report 

1967: Project 773. (Unpublished study received on unknown date under 8F0660; 

prepared by Oregon State Univ., Agricultural Experiment Station, Dept. of Fisheries 

and Wild- life, submitted by Dow Chemical U.S.A., Midland, Mich.; CDL: 094930-G) 

111458 Bond, C.; Wilson, D.; Malick, J. (1967) Progress Report on Aquatic Weed Research 

(Project 773). (Unpublished study received Jun 28, 1979 under 0F0863; prepared by 

Oregon State Univ., Agricul- tural Experiment Station, Dept. of Fisheries and 

Wildlife, sub- mitted by Dow Chemical Co., Indianapolis, IN; CDL:098349-I) 

For lithium salt of bromacil:

71-1 Avian Single Dose Oral Toxicity

MRID Citation Reference

13386 2025828 McGee, G.J.; Freeman, L. (1971) Acute Toxicity (LDI50^) in Bobwhite Quail. 

(Unpublished study received Dec 14, 1971 under 359-627; prepared by 

Biometric Testing, Inc. for Rhodia, Inc., submitted by Rhone-Poulenc, Inc., 

Monmouth Junction, N.J.; CDL:003176-B) 

133170 Mixture of 3 

actives – not 

found in 

012302

Posner, S.; McGee, G.; Freeman, L. (1971) Acute Toxicity (LD50) in Bobwhite 

Quail: ?Weed Broom Weed Killer|: Experimental Reference No. A-433. 

(Unpublished study received Dec 14, 1971 under 359- 627; submitted by 

Rhone-Poulenc, Inc., Monmouth Junction, NJ; CDL:023338-C) Ingredients

72-1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

133171 Mixture of 3 

actives see 

13387- same 

citation

Posner, S.; Grim, J. (1971) Acute TLm 96-hour (Static) of Weed Broom to 

Bluegill Sunfish ... and Rainbow Trout ...: Experimen- tal Reference No. F-393. 

(Unpublished study received Dec 14, 1971 under 359-627; prepared by 

Biometric Testing, Inc., submit- ted by Rhone-Poulenc, Inc., Monmouth 

Junction, NJ; CDL:023338-D) 
65

ACC 130653 see 

also 26183

2025827 McCann, J.A. EPA Animal Test Laboratory, Beltsville Md. Bluegill static tox 

with 80% Hyvar X weed killer

13387 2025829 Grim, J. (1971) Acute TLm 96-Hour (Static) of Weed Broom to Blue- gill 

Sunfish (?~Leponis machrochirus?~) and Rainbow Trout (?~Salmo 

gairdneri?~). (Unpublished study received Dec 14, 1971 under 359-627; 

prepared by Biometric Testing, Inc. for Rhodia, Inc., submitted by RhonePoulenc, Inc., Monmouth Junction, N.J.; CDL:003176-C) 

24963 2025826

2025830

McCann, J.A. (1970) ?Weed-Free LB: Toxicity to Bluegill|: Test No. 328. 

(U.S. Agricultural Research Service, Pesticides Regulation Div., Animal 

Biology Laboratory, unpublished report.) Bluegill static test with Chapman 

Weed-free LB 27.75% ai

26183 2025831

2025832

McCann, J.A. (1971) ?Hyvar X-1 Weed Killer: Toxicity to Bluegill|: Test No. 

367. (U.S. Agricultural Research Service, Pesticides Regulation Div., Animal 

Biology Laboratory, unpublished report.) 

72-2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

137445 2025317 Surprenant, D. (1983) Acute Toxicity of Liquid VIII Concentrate to Daphnia 

magna: Report #BW-83-8-1447; Study #079-0783-H55-110. (Unpublished 

study received Dec 9, 1983 under 2155-99; prepared by EG&G Bionomics, 

submitted by I. Schneid, Inc., Atlanta. GA; CDL:252042-A) 
66

Appendix C. Bromacil Ecological Incident Summaries Reported in the EIIS Database

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

I003601-001 White sucker

Notropis minnow

American eel

Blacknose dace

Probable Registered 

Use

Improper spraying of the herbicides 

2,4-D and Bromacil directly on the 

stream bank caused a significant 

losses of fish life in a tributary of 

Little Mill Creek. Investigation 

revealed that a cemetery caretaker 

assumed that there were no fish

present in the stream to worry about 

when he sprayed the stream banks on 

the cemetery property to control 

weeds. No analysis or any other data

provided in this report.

I004668-001/

I004875-001

Unknown fish Probable/ Highly 

Probable

Misuse 

(accidental)/ 

Misuse 

intentional

A fish kill occurred in Weiner Creek 

in Baton Rouge on March 10, 1996. 

A 55-gallon drum of 2,4-D and 

bromacil, and a 55-gallon drum of 

degreaser, had leaked into Wiener 

Creek causing the kill that extended 

about 1.6 miles along the creek. 

Criminal action is being taken by 

State and Federal authorities.

I005075-001 Alfalfa

Oats

Hay

Probable Misuse 

(accidental)

DuPont filed this report with the EPA 

to comply with FIFRA Section 

6(a)(2). A property owner in Texas 

has alleged that use of herbicide

Krovar (Bromacil+Diuron) by the 

neighbor adjacent to his property has 

resulted in the death of alfalfa, 

oats and forage hay. Herbicide was 

allegedly applied to a tank farm 

property approximately 2 days before 

a heavy rainfall. The tank dikes were 

later opened and three acres of pasture 

including a pond were allegedly 

exposed thus damaging alfalfa, 

oats and forage hay.

I005972-001 Live oak Probable Registered 

Use

Allegedly, the pesticide compounds in 

run-off from an adjacent plant site did 

injury to an individual's three (3) live 

oaks approximately 10 to 30 years old, 

subsequent to treatment by his 

neighbors application which affected 

his (individuals) property.

I006010-003 Grass

Bull rush (cattail)

Probable Misuse 

(accidental)

DuPont filed this report with the EPA 

to comply with FIFRA Section 

6(a)(2). Run-off of Sulfometuron 

methyl, Diuron plus Bromacil, and 

Glyphosate from an adjacent utility 
67

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

sub-station affected the non-target 

plants including pasture grass and bull 

rush (aquatic vegetation).

I007154-001 Catfish Possible Registered 

Use

A fish kill was possibly generated by a 

utility company on an alleged offtarget incident/water detection 

movement into a nearby two (2) acre 

pond from an electric substation.

However, on 13 April and 13 May, the 

Utility stated that copper sulfate had 

been applied to the pond since the soil 

application of the pesticide; 

considered to be relatively non-toxic, 

based on data from fish studies. 

DuPont makes the point that in the 

time frame before copper sulfate 

application, no sick fish with 

'sores' were reported in the pond by 

the pond owner.

I008184-001 Plants Possible Undetermined To comply with 6(a)(2) regulations, 

NCH Corp. reported the alleged 

damage to soil and trees upon 

exposure to bromacil. No information 

on the state, the county, or the types of 

plants damaged was included in the 

report. This was the single incident to 

be reported in the time frame of 

8/19/98 to 11/19/98.

I008441-001 Trees

Turf

Possible Undetermined To comply with 6(a)(2) regulations, 

NCH Corp. reported a complaint 

alleging that Certifen III leached from 

a fence line, where it was applied, into 

adjoining property where it damaged 

trees and turf. This took place in 

Maysville, KY, sometime between 

November 6, 1998, and February 6, 

1999.

I008956-001 Fish Probable Misuse 

intentional

To comply with 6(a)(2) regulations, 

NCH Corp. reported a number of 

incidents involving their products. 

This particular incident concerned 

bromacil which was dumped into a 

storm drain in Iowa and discharged 

into a local river. There was a report 

of some fish being killed.

I010837-020 Corn Possible Undetermined To comply with 6(a)(2) requirements, 

Novartis reported a complaint from 

Ulster, PA, that Bicep II damaged all 

60 acres of a corn crop. The inspector 

reported that the application was made 

within the guidelines on the label. 

"Stand reduction" was the problem, 
68

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

and a factor could have been Prowl 

which was also allegedly involved.

I010837-030/

I010837-031

Sunflower Possible/

Probable

Undetermined To comply with 6(a)(2) requirements, 

Novartis reported a complaint from 

Armour, SD, that there was a 

carryover injury to sunflowers 

resulting from an earlier use of 

Northstar. The symptom of the injury 

was uneven height. Here is the 

response of the inspector for Novartis: 

"Northstar carryover to sunflowers. 

Some stunting in areas throughout 

field. Stacked nodes and some 

yellowing. Soil samples sent (to - - -) 

to run test on pH and test for Beacon. 

Sunflower hybrid seed: Cargill SF 

270. Prowl applied PPI in 2000."

 This incident, and that described in 

I010837-031, concerns the same 

neighborhood in Armour, SD, and the 

same circumstances. 

I010837-045 Corn Possible Undetermined To comply with 6(a)(2) requirements, 

Novartis reported a complaint from 

Castile, NY, that BICEP LITE II 

damaged 100% of a corn crop; the 

acreage affected was not given.

I010837-048 Corn Possible Undetermined To comply with 6(a)(2) requirements, 

Novartis reported a complaint from 

Hornell, NY, that BICEP LITE II 

damaged all 12 acres of a corn crop. 

The company paid the complainant 

$1100 as a good will gesture and 

would send 20 gallons of BICEP 

LITE II MAGNUM to Agway Bath, 

NY. PROWL was reportedly another 

product involved but there was no 

indication of the extent of its 

involvement.

I010837-055 Soybeans Possible Undetermined To comply with 6(a)(2) requirements, 

Novartis reported a complaint from 

Mapleton, PA, that BICEP LITE II 

damaged 35 acres of soybeans out of 

65 that were treated. On the front 

page of the report, the item marked 

Acres Treated states 325. Obviously

there is a discrepancy of some sort in 

the reporting.

I012457-012 Peanut Possible Undetermined To comply with 6(a)(2) requirements, 

Valent reported a complaint from 

Smithfield, VA, that VALOR 

damaged two plots of peanuts, one of 

47.5 acres and the other 5 acres. Also 
69

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

applied were PROWL and DUAL 

MAG. The symptoms were described 

as: "Phytotoxicity. Stunted leaves."

I012457-013 Peanut Possible Undetermined To comply with 6(a)(2) requirements, 

Valent reported a complaint from 

Baconton, GA, that VALOR damaged 

two sites of peanut crops, one of 46.2 

acres and the other 56.5 acres. 

PROWL was also applied. The 

symptoms were described as: 

"Phytotoxicity. Stunted, stand 

reduction."

I012457-017 Peanut Possible Undetermined To comply with 6(a)(2) requirements, 

Valent reported a complaint from 

Sayre, OK, that VALOR damaged 30 

acres of peanuts. PROWL was also 

applied. The damage symptoms were 

described as: "Phytotoxicity: Burnt 

& wilted plants."

I012457-019 Peanut Possible Undetermined To comply with 6(a)(2) requirements, 

Valent reported a complaint from 

Whigham, GA, that VALOR damaged 

two peanut sites, one of 41 acres and 

the other 47.7 acres. PROWL and 

SONALAN had also been applied. 

The damage symptoms were 

described as: "Phytotoxicity: Stunting 

with stand reduction."

I012684-012 Peanut Possible Registered 

Use

To comply with 6(a)(2) requirements, 

Valent reported a complaint from 

Yale, VA, that VALOR damaged 40 

acres of peanuts. DUAL MAGNUM 

and TOUCHDOWN were also applied 

but no information was given about 

their application rates. The damage 

symptoms were reported as: 

"Phytotoxicity: Burnt leaf & petioles, 

slow emergence." This is a PA 

severity incident.

I012708-001 Oak

Shrub

Ornamental

Probable Undetermined To comply with 6(a)(2) requirements, 

DuPont reported a complaint from the 

Lake Wales Ridge area of Florida that 

BROMACIL damaged 40 mature oak 

trees, and many shrubs and plants. 

Here is the description of the incident: 

"Dennis Howard, PhD, Chief, Bureau 

of Pesticides; Florida Dept. of Agri. 

and Consumer Services (DACS), sent 

an e-mail (3/7/2002) to a 

representative of DuPont Crop 

Protection regarding water monitoring 

detects of shallow ground water wells 
70

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

in the Lake Ridge area of Florida and 

associated adverse effect allegations 

surrounding one of the wells. Dr. 

Howard previously communicated 

water detection results (5/2/2001) 

pertaining to the Lake Wales Ridge 

area wells and specifically the well 

that now has the additional allegations 

of adverse effects. This information 

was submitted (6/1/2001) see attached 

earlier submission. DuPont has 

submitted, over many years, ground 

water detection information regarding 

the Lake Wales Ridge area of Florida, 

as it has become known to us. The 

additional allegations of adverse 

effects came from the resident owner 

of a private well after they were told 

that their shallow well tested above 

the HAL (reported in 6/1/2001 

submission attached). The resident's 

allegations include death of landscape 

shrubs, perennials, and trees because 

use of the well for irrigation. In 

addition, the resident alleged he 

recently had his thyroid gland 

removed after developing a benign 

uni-nodular goiter possibly from 

drinking from this well. The resident 

used a reverse osmosis system that 

cleaned the water which was used 

until a new deep water well could be 

installed for the resident. In addition, 

two of the wells tested in this area 

were alleged to be over the bromacil 

Health Advisory Level (HAL) of 90 

ppb. Three other wells were over 

10% of the HAL but below the HAL, 

each detection of these wells will be 

counted in DuPont's next Quarterly 

Aggregate Submission under 

bromacil."

I013587-020 Evergreen Possible Registered 

Use

In the 2000-2001 Annual Report of 

the Pesticide Incident Reporting and 

Tracking (PIRT) Review Panel of 

Washington State, an incident that 

took place on March 2, 1998 in 

Adams County is reported. A 

combination of Bromacil and Diuron 

was applied, presumably to a right-ofway, but in 1999 a row of evergreens 

alongside the damaged party's home 

were dying. No residues were 
71

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

detected in the foliage samples that 

were taken, but a trace of one 

pesticide was found in the right-ofway. No pesticides were found 

outside of the right-of-way. The 

affected trees were located within 30 

degrees of the right-of-way.

 This is listed as a Severity 1 type of 

incident but there is nothing in the 

report to indicate the meaning of that

severity rating. No action was 

indicated.

I013850-001 Grass Possible Registered 

Use

An Ohio-based applicator used a 

railroad vehicle with flood jet and 

boom buster nozzles for the 

application of three products to 

railroad tracks on May 24, 2002. The 

products were Krovar IDF Herbicide, 

Roundup Original and Weeder IV. A 

resident next to the railroad reported 

that a third of the backyard was 

turning brown and dying.

I013884-004 Grass Highly Probable Registered 

Use

This is from the 1999 Annual Report 

from the Washington State 

Department of Health Pesticide 

Incident Reporting and Tracking 

Review Panel, November 2000, from 

the 1998 PIRT Data. Product applied 

last fall was carried by runoff, came 

across street and damaged three yards 

within two weeks.

I014177-001 Pepper, red bell Possible Registered 

Use

This is a Superior Court of California 

case. The plaintiff alleged that 

KROVAR I DF herbicide (Bromacil + 

Diuron) damaged their red bell pepper 

crop. KROVAR was applied in 

January 1998 to Tangerine orchard. 

In the summer of 2000, the tangerines 

were harvested and the trees removed. 

Early fall 2001, the field was irrigated 

and planted with 30 pounds of barley 

per acre. December 2001, the barley 

was discarded after reaching approx.... 

6 inches in height with no visible 

problems. On January 14, 2002, the 

soil was prepared for planting and the 

red bell pepper crop was planted. 

This is four years after the application 

of KROVER to an orchard. In March 

2002, it was noticed that a majority of 

the bell pepper seeds were not 

producing a plant, and plants that were 

growing, were stunted. After it was 
72

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

noticed that the plants were not 

growing, the plaintiff had analysis of 

the soil performed. It showed 0.134 

ppm of Bromacil. Other bioassays 

results were not given. At the present 

time, there are two other incidents 

which showed carryover of Bromacil 

from a different product effecting 

sunflowers.

I014409-062 Tree Possible Undetermined This incident was reported in the 

Washington State Dept. of Health 

Annual Report 1993, Pesticide 

Incident Reporting Review Panel, 

April 1994, prepared by the 

Washington State Department of 

Agriculture. A commercial applicator 

unknowingly mixed oryzalin and 

bromacil/diuron and made application. 

Damaged trees and shrubs. No 

analysis nor any State action.

I0144700-001 Grass Possible Registered 

Use

An alleged runoff from treated 

substations of OGE affected strips of 

sod downhill from the application. 

Treatment was bare ground at 12 

pounds per acre. Weather records 

indicated that these areas received 

heavy rains in May, which may have 

caused the runoff. There was a severe 

drought in the summer.

I015360-001 Deciduous tree

Pine tree

Possible Misuse 

(accidental)

To comply with 6(a)(2) requirements, 

DuPont reported a complaint from an 

applicator in John Day, OR, that 2 

trees 10-15 years old, one pine and 

one deciduous, and an older deciduous 

tree were damaged by the application 

of Krovar I DF Herbicide to a 

bareground driveway. The driveway 

was treated in 2000, 2001, and 2002 at 

the rate of 8 lbs/acre, and the owner 

began complaining of tree damage in 

2002. Near the edge of the driveway 

were a deciduous tree and a pine tree, 

both about 10-15 years old, and 

appeared to have yellowed 

leaves/needles, and the pine tree had 

shed much of the needles on the upper 

half of the tree. The homeowner also 

felt that there was some damage to an 

older deciduous tree behind the house.

 Specific language on the label 

warns against this situation and use.

I015382-001 Grass

Trees

Probable Undetermined To comply with 6(a)(2) requirements, 

DuPont reported an incident in 
73

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

Wyoming (location not mentioned) in 

which Krovar was applied to some 

weeds, after which a large rain came 

and washed the product down a 200 

foot embankment. The result was 

stated as "Now grass in his yard has 

turned brown and trees in his 

neighbor's yard are starting to turn 

brown." Evidently it was an instance 

of large runoff.

I016569-001 Glove willow trees Possible Undetermined To comply with 6(a)(2) requirements, 

DuPont reported an incident in Flora 

Vista, NM, in which DuPont's Krovar 

I DF Herbicide allegedly killed 45 

glove willow trees. The complainant 

stated that there is an oil pipe line 

behind their house, and for the past 

four years the land was sprayed with 

Krovar plus another chemical. 

Approximately eleven months ago, a 

weed company sprayed the fence line 

with those products but this time the 

spraying included a ten-foot width that 

was inside the complainant's land. The 

result was that 45 glove willow trees 

died.

I016610-001 Cottonwood

Pine

Willow

Probable Misuse 

(intentional)

It was alleged that a neighbor 

maliciously "threw onto the land" 

approximately four pounds of DuPont 

Krovar herbicide in order to kill their 

neighbors trees. In 2004, the dead 

grass area doubled in size to 30 by 10 

feet. There was one dying pine tree, 

one dying cottonwood tree and a dead 

willow tree.

In October 2004, an Arborist tested 

some white power on top of the dirt 

and the results reported 7.4% 

bromacil. Later in November 2004, 

some affected foliage was tested and 

showed 4.3 ppm of bromacil. It was 

alleged that the County sprayed a 

right-of-way with Telar (active 

ingredient: chlorsulfuron) and 

Dimension (active ingredient: 

dithiopyr) herbicides which drifted on 

to a field of peach trees. No analysis 

was reported. 75 to 100 peach trees 

were damaged.

I018527-001 Willow

Lilac

Highly Probable Undetermined DuPont Krover and Karmex 

Herbicides containing ingredients 

bromacil and diuron that were sprayed 

to control vegetation at an industrial 
74

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

site (Key Energy) caused damage to 

trees belonging to a private home 

owner adjacent to the spray site. Soil 

and plant tissue analyses were 

performed and detected the presence 

of bromacil and diuron in soil around 

trees.

I019519-045 Celery Possible Undetermined Grower reported crop loss happened 

40-60 feet next to railroad track to the 

Ventura County Agricultural 

Commissioner office on April 9, 2008. 

Plant damage was about 7 acres of 35 

acres of celery. A pest control 

company located in Chino sprayed for 

weeds around the railroad track 2-3 

weeks prior to the noticeable celery 

damage. The herbicides sprayed 

include product Karmex with active 

ingredient diuron, product Krovar 

with active ingredient bromacil and 

diuron, product Payload with active 

ingredient flumioxazin, and product 

Razor with active ingredient 

glyphosate.

I020725-004 Celery Possible Undetermined A grower reported crop damage to 

Ventura County Agricultural 

Commissioner's Office and celery 

field about 40 to 60 feet next to 

railroad track showed root damage. A 

pest control company located in 

Chino, California sprayed for weeds 

around the railroad track 2-3 weeks 

prior to the noticeable celery damage. 

Chemical analysis showed presence of 

Diuron and Bromacil in the celery 

samples collected from the suspected 

field.

I020180-033 Brussels sprouts Possible Undetermined Oust XP and Krovar herbicides had 

caused damage to brussels sprouts by 

rain runoff from the railroad right-ofway that was located adjacent to the 

growing site. In January 2008, an 

application of the herbicides Krovar 

1DF and Oust were made to the 

railroad by a pest control business. 

Brussels sprout transplants were 

planted on the damaged site during the 

month of April. The grower noticed 

stunting and dying off of 

approximately 9 acres of Brussels

sprouts around May 15, 2008. Diuron, 

one of the active ingredients of 

Krovar, was detected in soil samples 
75

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

taken from the treatment site, but not 

from soil samples taken from the 

brussels sprout field.

I020459-001 Wheat Possible Undetermined The Washington State Department of 

Agriculture reported in the 2002 PIRT 

Report a case that involve alleged drift 

and run off of herbicides from road 

ROW applications that damaged a 

wheat field. Diuron, bromacil, and 

imazapyr were applied along a 

freeway and a county road, and were 

also detected on the wheat.

I020459-005 Ornamental Possible Undetermined Three ornamental trees at a residence 

were damaged by herbicide. The 

herbicides may have come from an 

off-label application to a driveway, or 

possibly from drift from spraying of a 

roadside or an adjacent field. The 

applications were made by a 

commercial pest control company to a 

non-farm residence. The Washington 

State Department of Agriculture 

(WSDA) lab detected bromacil and 

diuron in leaves from the trees. 

Glyphosate, also applied by the 

company, was found in one of the 

trees damaged by the herbicide.

I020459-035 Ornamentals (Juniper) Possible Misuse 

(accidental)

The Washington State Department of 

Agriculture reported in the 2002 PIRT 

Report a case that involved damage to 

juniper trees that were caused by an 

application of of Krovar (active 

ingredients bromacil and diuron). 

Krovar was applied for weed control 

around the newly planted Juniper 

plants almost a year ago. The Krovar 

label states "not to be used in or 

around houses" and "do not to sites 

which have roots of desirable plants 

growing in the treatment zone as plant 

injury or death may occur. The trees 

likely died from root uptake of the 

product.

I020627-005 Trees

Shrubs

Possible Misuse 

(accidental)

The Office of Environmental Health 

and Safety, Washington State 

Department of Agriculture Annual

report 2003 indicates a case that 

involve alleged drift or overspray 

from roadside application of the 

herbicides 2,4-D, diuron, and bromacil 

resulted in injury to multiple trees and 

shrubs on private property. The 

application was a misuse because it 
76

Table C-1. Bromacil Incident Report Summaries

Incident # Organism(s) Affected Certainty of 

Involvement

Legality of 

Use Description

was made under conditions conducive 

to drift.

I021074-001 Cottonwood

Oak

Pine

Cedar

Grass

Highly Probable Undetermined DuPont Hyvar Herbicide (active 

ingredient bromacil) was sprayed by a 

neighbor three times to kill weeds. 

There was 3 inches of rain which 

caused runoff of the herbicide, killing 

grass and assorted trees in his yard 

and his neighbor's yard. There was a 

clear swath of dead plants from the 

application site to the neighbor's 

house 200 ft away. The product 

caused damage to oak, cedar, pines, 

and cottonwoods trees as well as 

grasses. The arid area had little 

rainfall before the 3-inch rain event. 

The neighbor who applied the 

herbicide product works for the 

railroad and brought the herbicide 

home to spray on weeds. This was a 

misuse of the product.