UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

taA~ 22 201l 

MEMORANDUM 

SUBJECT: Use Characterization for Atrazine 

OFFICE OF 

CHEMICAL SAFETY AND POLLUTION 

PREVENTION 

FROM: Sepebr 

Science 

Haddad, 

Information 

Environmental 

and Analysis 

Protection 

an h 

Specialist jq .. ~ -' ~ 

THRU: 

Bill Phillips, II, PhD, Agronomist pop..-

Biological Analysis Branch 

Diann 

Science 

Sims, 

Information 

Chief <O~ and Analysis Branch 

Biological 

Arnet Jones, 

Analysis 

Chief 

Branch 

~ Biological and Economic An ysis Divisi n 

TO: James Hetrick, Senior Scientist 

Environmental Fate and Effects Division (7507P) 

BEAD Product Review Panel Date: March 7, 2012 

INTRODUCTION 

In this memorandum, BEAD is providing EFED an atrazine use characterization for use in their 

risk characterization document in preparation for the June 2012 Science Advisory Panel (SAP) 

meeting on atrazine. 

The information in this memo includes: a listing of agricultural and non-agricultural use sites; 

common formulations; application methods, and application timing for the crops with the highest 

use (corn, sorghum and sugarcane); agricultural usage data (typical use patterns, an updated 

screening level estimate of agricultural uses for all crops for which data were available, and 

national mapping data); and non-agricultural usage information for which data were available. 

The Appendix to this memo is an aggregated report which includes detailed label use and 

application information for atrazine. 
Information on use sites, formulations, application methods, and application timmg in this 

section of the document has been obtained from various EPA sources including the 2006 

Atrazine Reregistration Eligibility Decision (RED) document, databases such as OPPIN and the 

Label Use Information System (LUIS), and confirmed through a review oflabel information. 

Agricultural Use Sites 

.Atrazine is ,a triazine herbicide first registered in 1958. Atrazine is currently registered for use 

against broadleaf and some grassy weeds in com, sweet com, sorghum, soybeans, sugarcane, 

wheat, oats, macadamia nuts, guava, and range grasses. Application in wheat is to wheat stubble 

on fallow land following wheat harvests when the land is not cultivated; and therefore, wheat is not 

the target crop. Application to range grasses is for the establishment of permanent grass cover on 

rangelands and pastures under USDA's Conservation Reserve Program (CRP in OK, NE, TX, and 

OR) and range/pastureland. Most of the atrazine applied to com and sorghum is applied 

preemergence. 

Non-Agricultural Use Sites 

Atrazine is registered for use in conifer forests, Christmas tree farms, sod farms, ornamental 

grasses, ornamental plants, ornamental turf, outdoor residential (given the specific nature of the 

lawn uses, much of atrazine's use on lawns is confined to Florida and the Southeast), schools, parks, 

playgrounds, and athletic fields. 

Atrazine can also be used on roadsides, rights-of-ways, airfields, vacant lots, roadsides, lumber 

yards, agricultural buildings, industrial sites and storage sites. 

Formulations: 

Atrazine is available in many formulations including granular, wettable powder, water 

dispersible granules, emulsifiable concentrate, flowable concentrate, soluble concentrate, readyto-use solution, and water soluble packs. 

Application Methods: 

Atrazine may be applied by groundboom sprayer, aircraft, tractor-drawn spreader, rights-of-way 

sprayer, low pressure handwand, backpack sprayer, lawn handgun, push-type spreader and belly 

grinder (hand-crank spreader). . 

Application Timing on Crops With the Highest Use: 

Com: Applications to com are most often preemergence (mid-April through mid-May in the 

major com growing areas). Posteinergence applications are most likely to occur up to the end of 

June, until com reaches 12" in height. There will be some variability in timing based on 

geographical regions. 

Sorghum: Applications to sorghum are most often preemergence (mid-May to mid-July in the 

major sorghum growing areas). Postemergence applications are most likely to occur up to the 

end of August. There will be some variability in timing based on geographical regions. 

2 
Sugarcane: Applications to sugarcane are usually at planting (fall), in the spring after 

emergence, and an additional postemergence application '(often at layby). However, these later 

applications are only used if pest pressure dictates. Also, ratoon crops may face heavier weed 

pressure, and therefor.e additional applications are more likely in sugarcane ratoon crops. 

AGRICULTURAL USAGE DATA 

Based on private market survey data from 2000-2010 usage averaged approximately 72 million 

pounds active ingredient (a.i.) for 71 million acres. Figure 1 presents atrazine agricultural usage 

in pounds a.i. (lbs. ai) applied between 2000 and 2010. 

FIGURE 1. Atrazine A ricultural Usa e lied 2000-2010 

100,000,000 ,---------------------

50,000,000 -i--.---.----.---r---.---,----,---r--.,...---.,....-----, 

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 

Years 

Source: Proprietary Data, 2000-2010 

Screening Level Usage Analysis Data (2003-2010) 

Table 1 provides the most recent Screening Level Usage Analysis (SLUA) prepared in 

November, 2011. The SLUA provides available estimates of pesticide usage data for atrazine 

on agricultural crops in the United States. The reported usage data in the SLUA are obtained 

from various sources and are merged, averaged and rounded so that the presented information is 

not proprietary, or business confidential. 

SLUA data sources include USDA-NASS (United States Department of Agriculture's National 

Agricultural Statistics Service) (2003-2010) and Private Pesticide Market Research (2003-2010). 

These results reflect amalgamated data developed by the Agency and are releasable to the public. 

Limitations to the data are: 

• 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. 

3 
• Usage data on a particular site may be noted in data sources, but not quantified. In 

these instances, the site would not be reported in the SLUA. 

• Non-agricultural use sites (e.g., turf, post-harvest, mosquito control, etc.) are not 

reported in the SLUA. 

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

factors, including, but not limited to data collection or reporting errors, or application errors. 

Table 1. Screening-Level Estimates of Agricultural Uses of Atrazine (2003-2010) 

(SLUA, dated 11115/2011) 

Crop Lbs. A.I. - 1 Com 60,000,000 

2 Barley+ 7,000 

3 Fallow 350,000 

4 Pastureland 60,000 

5 Pecans + 1,000 

6 Potatoes+ . 11,000 

7 Sorghum 5,600,000 

8 Soybeans . 500,000 

9 Sugarcane 2,000,000 

10 Sunflowers + 6,000 

11 Sweet.com 400,000 ~ 

12 Wheat 100,000 

All numbers rounded. 

<2.5 Less than 2.5 percent of crop treated 

<1 Less than 1 percent of crop treated 

Percent Crop Treated (pCT) 

"~ Avg. Max. 

, 60 t, 70 

<1 ~ <2.5 

<2.5 5 

," <1 <2.5 , . <1 <2.5 

<2.5 <2.5 

65 ~ 70 

<1 <2.5 

65 75 

<1 , 

,~ <2.5 -

70 75 

<1 <2.5 

+ Crops not known to be listed on active end use product registrations when this report was run. 

Typical Use Patterns (2006-2010) 

For the more recent timeframe of 2006-201 0, usage averaged approximately 66 million pounds 

a.i. for 67 million acres. Atrazine is. typically applied at a rate of 0.3-2.3 pounds active 

ingredient per acre (lbs ail A) depending on the crop as shown in Table 2. (Proprietary Data, 

2006-2010). 

In addition to the average application rate data, a rate distribution was generated to calculate an 

upper bound rate for each crop. The upper bound rate in this analysis is defined as the rate at 

which 90% (or as close to 90% as possible) of the acres treated with atrazine were treated at, or 

below that rate, as shown in Table 2. 

4 
TABLE 2. Typical Use Patterns for Atrazine Used on Selected Crops (2006-2010) 

Crop Average Application Average number of Upper bound rate* (lbs 

Rate (lbs ail A) Applications Per ailA) percentile in 

Year parenthesis 

Com 1.0 1.2 1.60 (89%); 1.75 (92%) 

Sorghum (Milo) 1.0 1.2 1.5 (85%); 1.60 (90%); 

1.75 (93%) 

Sugarcane 2.3 1.4 3.75 (82%); 4.0 (100%) 

Fallow 0.9 1.1 1.25 (79%); 1.45 (85%); 

1.5 (95%) 

Sweet Com 0.8 1.1 1.5 (91%) 

Wheat, Spring 0.3 1.0 0.25 (67%); 0.45 (68%); 

(stubble) 0.5 (100%) 

Wheat, Winter 0.7 1.0 0.75 (83%); 0.90 (91 %); 

(stubble) 1 (100%) 

Source: Propnetary Data, 2006-2010 

*The upper bound rate (90th percentile) is defmed as the rate at which 90% (or as close to 90% as possible) of the 

acres treated with atrazine were treated at or below that rate. For example, in the above table, for sugarcane, 82 

percent of the acres are treated at 3.75 lbs aj.lA or less, while the remaining 18 percent are all treated at 4.0 lbs 

aj.lA. 

Top Crops and States with Highest Use (2006-2010) 

For 2006-2010, the top crop in terms of average annual pounds of active ingredient applied was 

com (88%), followed by sorghum (8%), and sugarcane (2%) and sweet com and fallow (1 % 

each). Spring and winter wheat stubble accounted for less than one percent of total pounds a.i. 

used during this period. 

As shown in Figure 2, between 2006-2010, the states with the most agricultural usage in terms of 

pounds a.i. applied were Illinois (17%), Iowa (11 %), Nebraska (10%), Indiana and Kansas (9% 

each), followed by Missouri, Ohio, Texas, and Kentucky with less than 5% each. The "other" 

category includes 29 other states with Minnesota, Michigan and Wisconsin having the most 

usage among those states. 

5 
,..-..-----------~---->----------__A.f lied) 2006-2010 

KENTUCKY 

2% 

6% 

Source: Proprietary Data, 2006-2010 

National Mapping Data 

Another measure of usage is the use intensity. In this analysis, the use intensity is expressed as 

the pounds a.i. applied per acre of land in fanns. This differs from the application rate, which is 

expressed as the pounds a.i. applied per treated acre. Figure 3 is a map of agricultural pesticide 

usage at the Crop Reporting District (CRD) level that spatially represents atrazine use intensity 

in the US. As shown, areas such as Florida and the com producing states (colored in red) have 

the highest use intensity. 

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 

fannland in a CRD to normalize for the variation in fannland between CRDs. Fannland acreage 

was obtained from USDA (2007). 

Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2006-

2010). The survey data are limited to the states that represent the top 80-90 percent of acreage 

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

survey. CRDs showing no usage of pesticides may be due to either the lack of pesticide use in 

the region or non-participation in the agricultural surveys. In addition, across the years, there 

may be variations in the specific crops included in the CRD survey. This may result in a lower 

annual average for the CRD. 

6 
Figure 3. Atrazine Usage by Crop Reporting District (2006-2010) 

Average Pounds per 

1,000 Acres of Farmland 

. 0-8 

9 - 49 

0 50 - 99 

100 - 214 

_ 215-580 

Sources: 

Proprietary Data. 2006-2010 

USDA, 2006-2010. NASS Crop Reporting Districts. 

USDA, 2007. Census of Agriculture. 

NON-AGRICULTURAL USAGE 

N 

I 

Information on non-agricultural usage in this section of the document has been obtained from 

available private market survey data from Kline & Co. The information provided on atrazine use 

in this section is for select non-agricultural use sites and does not represent all non-agricultural 

usage (this is due to data limitations since data was not available for all non-agricultural use 

sites). 

Non-agricultural usage data for professional applications to turf and ornamentals is available for 

2002,2004 and 2006 (Table 3). Over this time period, there was a notable increase in use by 

lawn care operators and on golf courses, institutional turf, and turf farms (Kline & Co., 2002, 

2004, 2006). 

7 
Table 3 . Atrazine Select Non-A~ricultural Usa~e (pounds A.I.) (2002,2 

Site 2002 2004 

Golf Courses N/A 3,085 

Institutional Turf 3,493 11,479 

Landscape 593 41,978 

Lawn Care Operators 211,561 97,095 

Turf Farms 145,013 269,829 

Nursery/Greenhouse N/A 7,029 

TOTAL Reported.(lbs. a.i.) 360,660 430,495 

N/A= no atrazine use was reported in the 2002 reports 

Source: Kline & Co., 2002, 2004, and 2006 

2006 

6,431 

152,079 

204 

686,107 

302,636 

7,824 

1,155,281 

004,2006) 

For the consumer market, approximately 400,000 pounds a.i. was applied in 2005 as lawn 

herbicide. Use was reported in the earlier consumer reports (2001 and 2003); however, the use 

was not quantified because it was below the reporting threshold. 

REFERENCES 

Proprietary Data, 2000-2010 

Kline & Co., Inc. 2001-2006 

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

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

USDA, 2007. Census of Agriculture. Online: 

http://www .agcensus. usda. gov lPublications/2007 /index.asp 

US EPA, 2006, Atrazine Reregistration Eligibility Decision Document 

cc: Melanie Biscoe 

8 
Appendix. Atrazine Uses and Application Information Report 

The aggregated report includes label use and application information for atrazine. This 

information which is based on the LUIS generated EFED Table 1 Aggregated Report (submitted 

to EFED in electronic format in a separate transmission) includes information formatted to 

EFED's specification on use site, application equipment type, application method type, 

application timing, and formulation description. Additional information from the label, where 

available, is also included in the report, including maximum single application rates, maximum 

number of applications per crop cycle (CC) or year, minimum retreatment intervals, information 

on geographic use restrictions, and sample label registration numbers for each use site. 

As presented in the Appendix, per the label data, for com use, applications can be made up to a 

maximum single application rate of 2.1 lbs aj.l A; for sorghum up to 2 lbs aj.l A; for sugarcane 

up to 4lbs aj.lA; for wheat (stubble) up to 2.21bs aj.lA, and for agricultural fallow and 

conservation reserve uses up to a rate of 2.2 lbs aj.l A. Additionally, applications can be made 

up to at a maximum single application rate of2lbs aj.lA for Christmas tree plantations; for 

forest trees up to 4lbs aj.lA; for golf course turf up to 2lbs aj.lA; for ornamental lawns and turf 

up to 2.7 lbs aj.l A; for ornamental sod farms up to 4 lbs a.i.I A; and for residential lawns up to a 

single maximum application rate of 2.7 lbs aj.l A. 

9