UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

DEC 05 2012 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile for Registr Propazine (080808) 

FROM: Bill Phillips, PhD, Agronomis 

Biological Analysis Branch 

1'7 n . .I Cynthia Doucoure, Environmental Protection Specialist ~ ~ 

THRU: 

Science Information and Analysis Branch 

Andrew Lee, Economist (],.or (\;+. Yv\. \l ~ Economic Analysis Branch VU ~ Biological and Economic Analysis Division (7503P) 

Amet Jones, Chief 

Biological Analysis Branc 

Diann 

Science 

Sim

Information 

s, Chief ~ 

and Analysis Branch 

Timothy Kiely, Chief A yJ\ ~ ·_,Q_ 

Economic Analysis Branch U } ~\.) Biological and Economic Analysis Division (7503P) 

TO: Kaitlin Keller, Chemical Review Manager 

Risk Management and Implementation Branch 4 

Pesticide Reevaluation Division (7508P) 

Product Review Panel date: October 10,2012 

Page 1 of8 
INTRODUCTION 

The purpose of this document is to convey usage information and a broad overview of the pest 

management roles of pesticides that are beginning to undergo registration review. The 

anticipated audience consists of the team of EPA staff currently evaluating the registration status 

of propazine, and eventually the general public. This document builds upon the data already 

provided in the "Usage and Label Use Data Packages" that are also provided to Registration 

Review teams by BEAD. The document is based on information and data available to BEAD as 

of August 2012 

Propazine (2-chloro-4,6-bis(isopropyalamino)-s-triazine) is in the Weed Science Society 

herbicide group 5 (s-triazine) with the mechanism of action of inhibiting photosynthesis in 

photosystem II (PSII). Propazine is applied preemergence in grain sorghum (Sorghum bicolor) 

in order to control broadleaf and grass weeds. In greenhouse crops and in non-agricultural use 

sites this herbicide is applied prior to weed emergence. 

In 1989 the registration for propazine use in grain sorghum was cancelled, however its use was 

allowed under a Section 18 for the years 1993-1995. EPA proprietary data shows that use 

continued through 2001(Figure 1). BEAD was unable to determine why such uses continued for 

so long following 1995. In 2007 a new registrant applied for and received a registration for the 

use of this herbicide in sorghum. Currently propazine is used in grain sorghum as well as in 

greenhouses for containerized ornamentals. 

Even though the registrant did not fulfill a data requirement needed for the reregistration of the 

herbicide, tolerances for grain sorghum still remained, and because greenhouse use was still 

labeled, propazine was a part of the Agency's 2006 triazine cumulative assessment. In June of 

2006 the "EPA [had] concluded that, with the mitigation measures in the individual atrazine and 

simazine decisions, the cumulative risks associated with the triazine pesticides are below the 

Food Quality Protection Act (FQPA) regulatory level of concern. " 1 As for any risks associated 

with propazine, in August of 2006 "EPA [had] evaluated the existing propazine sorghum 

tolerances and determined that there [was] reasonable certainty that no harm to the general 

population, infants, children, or other major ident{fzable subgroups of consumers [would] result 

from these tolerances. Dietary exposure to propazine was determined to be essentially zero; 

propazine, therefore, was found to pose no risk concerns." 

HISTORY OF BEAD ASSESSMENTS FOR PROPAZINE 

In its 2004 (Phillips and Zinn, 2004) and 2005 (Phillips et al., 2005) assessments, BEAD 

concluded that in the narrow scope of pre-emergence control of broadleaf weed species in 

sorghum crop production, propazine is an agronomic replacement for atrazine; however, this 

does not preclude the possible use of atrazine as a post-emergence "rescue treatment" in fields 

where an application of propazine was made and failed to provide adequate control. These 

works by BEAD suggest the potential of propazine as an alternative to atrazine, which is 

currently under the Agency review for its effects potentially relevant to human health risk 

assessment. 

1 Triazine Cumulative Risk Assessment and Atrazine, Simazine, and Propazine Decisions: June 22, 2006 

http://www.epagov/oppsmll /cumu I at ivc/triazine fs.ht m#howtocomment 

Page 2 of8 
COMMON FORMULATIONS AND APPLICATION METHODS 

Propazine is commonly formulated as a flowable concentrate and applied via aerial and ground 

spray applications, using flat fan-type nozzles for uniform broadcast applications and band 

treatments. Propazine is also applied through flood or drench nozzles in greenhouse 

applications. 

USAGE 

Agricultural Use Trend, 1998-2011 

Overall use ofpropazine on grain sorghum in the U.S., as reported in private market research 

surveys, increased between 1998 and 2009 as shown in Figure 1. A sharp increase in use of 

propazine occurred between 2008 and 2009, followed by a sharp decrease in recent years. No 

use ofpropazine was reported during the years 2001-2006. A similar trend was found for total 

area treated as shown in Figure 2. 

Figure 1: Propazine: Pounds a.i. Applied, 1998-20 II 

200,000 

0 

p,fb p,"> ~<:) ~'\. ~')., ~'>) d> ~<, d<> ~ ~tO ~0, ~<:) ~"" '\.Oj ...,Oj ').,~ ').,~ ').,~ ').,~ ').,~ ').,~ ').,~ ').,~ ').,~ ').,~ ').,<:) ').,<:) 

Year 

Source: EPA Proprietary Data, 1998-20 II 

Page 3 of8 
Figure 2. Propazine: Total Area Treated (acre), 1998-2011 

250000 

0 

'i'J'b ?>0) ~<:> ~"' ~'\. ~'? ~~ ~<, ~'o ~ ~'b ~0) ~<:> ~"' "'Oj ..... Oj '\.<S '\.<S '\.<S '\.<S '\.<S '\.<S '\.<S '\.<S '\.<S '\.<S '\.<:> '\.<:> 

Year 

Source: EPA Proprietary Data, 1998-2011 

Agricultural Use 2007-2011 

During the 2007-2011 timeframe, use ofpropazine on grain sorghum averaged approximately 

74,000 pounds annually and was applied on average to 96,000 acres at an overall average a.i. 

application rate of 0.8 lbs/acre. In earlier years, the top states for use of propazine in terms of 

pounds a.i. applied and total area treated were Texas, with a little over half the market, followed 

by Nebraska (25%) and Kansas (12%) as shown in Figure 3. However, based on private market 

research during the 2007-2011 period, Texas clearly dominated the market in terms of pounds of 

propazine and total area applied (92%), followed by Kansas (4%) and New Mexico (4%). During 

this recent period, there was no reported use of propazine on grain sorghum in Nebraska and 

Missouri as shown in Figure 4. 

Figure 3. Propazine Use on Grain Sorghum, Top States, 1998-2000 

Pounds AI 

Source: EPA Proprietary Data, I 998-2000 

IS::.C·URI 

C.% 

r-----------------------------~ 

Page 4 of8 

Total Area Treated 

MISSOURI 

69'. 
Figure 4. Propazine Use on Grain Sorghum, Top States, 2007-2011 

Pounds A.l. 

Source: EPA Proprietary Data, 2007-20 II 

Non-Agricultural Use 

l<ANSA~ 

4% 

4ro 

r-----------~-----------------, 

Total Area Treated 

No reported usage of propazine in the non-agricultural sector was found in available sources. 

INFORMATION THAT MAY BE USEFUL FOR BEAD'S FUTURE WORK ON 

PROPAZINE 

Obtaining additional information on typical propazine use in the non-agricultural sector would 

improve future BEAD assessments of the importance of propazine and may be required as part 

ofthe registration review of this pesticide. Requested data should include, but not be limited to, 

application timing, application rate, application method, and application frequency. 

CONCLUSION 

The propazine overall average a.i. rate for application to sorghum has been inconsistent in the 

area treated and the number of pounds applied. Inconsistent use notwithstanding, it still remains 

that a small fraction of the sorghum crop is treated. 

REFERENCES 

EPA 2004. Atrazine/Propazine Use on Sorghum. Phillips and Zinn, August 25, 2004 

EPA 2005a. 'Atrazine and Propazine Use Rates in Sorghum for Potential Co-occurrence (DP 

308550) - Phillips, Zinn, and Kiely, October 11, 2005 

Page 5 of8 
EPA 2005b. Projected Percent of Crop Treated Estimates for Propazine on Sorghum (080807). 

Kiely and Smearman, January 11, 2005. 

EPA 2007. Refined Projected Percent Crop Treated (PPCT) Estimates for Use ofPropazine and 

Atrazine on Sorghum in Texas, PC Code 080808, DP Barcode 335065 - Alsadek and Zinn, 

March 9, 2007. 

EPA Proprietary Data, 1998-2011 

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

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

USDA, 2007. Census of Agriculture. Online: 

http://www .agcensus. usda. gov /Publications/2007 /i ndex.asp. 

Page 6 of8 
APPENDIX 

Agricultural Usage by Crop Reporting District 

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 farms. This differs from the application rate, which is 

expressed as the pounds a.i. applied per treated area. Note that the average application rate is 

calculated to be about 0.8 lb a.i. per acre, equivalent to 800 lb a.i. per l ,000 acres. The most 

intense use shown on the map is about 5 lb a.i. per 1,000 acres of farmland. Figure 5 spatially 

represents propazine's use intensity in the U.S., which is relatively greater in Texas. 

Figure 5. Propazine Usage by Crop Reporting District (2006- 2010) 

Propatino • Use (2006·20 I 0) by Crop Reponing 

Dimict Average Pounds per 1.000 Acres of 

Farmland 

- <002 

- 0.2 - 0.3 

0 4 -05 

- 06- 5.1 

Page 7 of8 
This is a map of agricultural pesticide usage at the Crop Reporting District (CRD) level prepared by BEAD 

for use in the Environmental Fate and Effects Division documents. These maps are used to help visualize 

where the pesticide being considered is most likely to be used and can be helpful in scenario selection and 

placing the exposure assessment in context. CRDs are boundaries created by USDA NASS which are 

aggregates of counties (USDA, 20 10). Pesticide usage is displayed as average pounds (for the years 2006-

20 I 0) per 1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. 

Farmland acreage was obtained from USDA (2007). Farmland or "land in farms" is defined as follows: 

The acreage designated as "land in farms" consists primarily of agricultural land 

used for crops, pasture, or grazing. It also includes woodland and wasteland not 

actually under cultivation or used for pasture or grazing, provided it was part of 

the farm operator's total operation. Large acreages of woodland or wasteland 

held for nonagricultural purposes were deleted from individual reports during 

the edit process. Land in farms includes CRP, WRP, FWP, and CREP acres. 

Land in farms is an operating unit concept and includes land owned and 

operated as well as land rented from others. Land used rent free was reported as 

land rented from others. All grazing land, except land used under government 

permits on a per-head basis, was included as "land in farms" provided it was 

part of a farm or ranch. Land under the exclusive use of a grazing association 

was reported by the grazing association and included as land in farms. All land 

in American Indian reservations used for growing crops, grazing livestock, or 

the potential of grazing livestock was included as Land in farms. Land in 

reservations not reported by reservation, individual American Indians or nonNative Americans was reported in the name of the cooperative group that used 

the land. In many instances, an entire American Indian reservation was reported 

as one farm (2007 Census of Agriculture, USDA). 

Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2006-201 0). The 

survey data are limited to the states that represent the top 80-90% 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. 

This map displays ratio data (i.e., average pounds per I ,000 acres of farmland) summarized at a very highlevel. Readers are strongly cautioned against trying to over interpret the map without examination of the 

underlying data. The underlying data may explain some of the many reasons that a Crop Reporting District 

may have a high value for a particular active ingredient such as significant acreage (compared with the CRD 

as a whole) of a crop or crops with a high application rate and frequency of application. 

The reader should pay particular attention to the figure legends and realize that a map prepared for a 

particular chemical is not directly comparable to a map prepared for a different chemical. Scale and units of 

measurement do matter and may be different between maps. 

Sources: 

Proprietary Data. 2006-20 I 0 

USDA, 2006-20 I 0. NASS Crop Reporting Districts. Online: 

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

USDA, 2007. Census of Agriculture. Online: hnp://www.agcensus.usda.gov/Publications/2007/index.asp 

Page 8 of8