UNITED STATES ENVIRONMENTAL PROTECTION AGENC Y WASHING TON, D .C. 20460 

## DEC 12 

## 20a

MEMORANDUM**~** . ; 

## .

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION

SUBJECT: BEAD Chemical Profile (BCP) for Registration Review: MCPA Case (030501, 030511, 030502,030516,030563 and 030564) FROM:

THRU: Sunil Ratnayake, Ph.D., Biologist 

# /lL() \_ 0 Biological Analysis Branch 

# l c .

# ~ '\ ;}

# ~ Jihad Alsadek, Ph.D., Economist 

## J 

# d..J A- 

# t-AL,Ut{ Science Information and Analysis Branch Derek Berwald, Ph
.D. , Economist

## ~ Economic Analysis Branch

### ~**~** //

- Biological and Economic Analysis Division (75 03P) Arnet Jones, Chief Biological Analysis Branch Diann Sims, Chief Science Information and Anal :t ysis Branch**~** Timothy Kiely, Chief**~** Economic Analysis Branch Biological and Economic Ana y Division (7 P) TO: Christina Scheltema, Chemical Review Manager Risk Management and Implementation Branch 3 Pesticide Re-evaluation Division (7508P)
Peer Review Panel date: August 14, 2013SUMMARY MCPA (2-methyl-4-chlorophenoxyacetic acid) is a selective, post-emergence systemic herbicide used for the control of annual and perennial broadleaf weeds. This herbicide was first registered in the United States in 1973 (USEPA, 2004). MCPA belongs to the phenoxy carboxylic acid family and according to the Weed Science Society of America (WSSA) mechanism of action classification; it belongs to the synthetic auxins (Group 4). Phenoxy herbicides act by mimicking the action of natural hormones and produce uncontrolled cell division and plant growth. MCPA is absorbed by the foliage and roots and translocated throughout the weed. The mechanism of action ofthis herbicide appears to affect the cell wall plasticity and nucleic acids (DNA, RNA) metabolism. Products ofMCPA are available in salt, ester, or amine forms. Ester form ofMCPA is more volatile than other formulations. MCP A is used in mixture with many other products to achieve a wider spectrum of weed control. Registered agricultural use sites of MCPA include: barley, flax, grasses grown for seed, oats, pastureland, peas (unspecified), rye, and wheat. The registered non-agricultural use sites of MCPA include: nonagricultural areas, uncultivated areas/soil s, ornamental lawns and turf. There are no reported usage data for some ofthe registered crops such as flax because they are not surveyed. It is mainly used on wheat and barley in addition to other crops such as oats and green peas. The available data on MCPA use on non-agricultural sites (Kline 2002 , 2004 and 2006) show changes, but not in a consistent direction. The recent use of MCPA shows 1.3 million lb s . a.i. used on ornamental lawns , (Kline 2011). 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 ofthe team ofEPA staff currently evaluating the registration status ofMCPA 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 Regis tration Review teams by BEAD. The document is based on information and data avai lable to BEAD as of July 24 1h of2013
. This is a case level BCP where there are many PC codes, some of which have active products and others do not. The following PC codes do not have active products: 030553, 030556 and 030562. The rest ofthe PC codes have active products. 

### USE SITES Agricultural Use S ites MCPA registered agricultural use sites include: barley, flax, grasses grown for seed, oats, pastureland, peas (unspecified) , rye and wheat. (There are no reported usage data for some of the registered crops such as flax because they are not surveyed.)

Page2Non

-Agricultural Use Sites MCPA registered non-agricultural use sites include: nonagricultural areas, uncultivated areas/soils, ornamental lawns and turf. COMMON FORMULATIONS AND APPLICATION METHODS Formu l ations include granular, emulsifiable concentrates, soluble concentrate / liquids and wettable powders
. MCPA can be applied using aircraft, tractor mounted ground sprayers, broadcast spreaders , and hand-held sprayers. HISTORY OF MCPA AND BEAD PRODUCTS BEAD has not performed any assessments of MCPA in the past, other than Screening Level Usage Analysis (SLUA), which shows that the percent of the crop treated is above 20% in both wheat and bar ley, and above 15% in green peas. MCPA USAGE Agricultural Usage Trends: 1998-2011 As shown in Figure 1, agricultural usage ofMCPA, in both total area treated (TAT) in acres and total pounds in active ingredient applied, has been trending down since 1998
. From 1998 to 2011, an annual average of approximately 3 million pounds ofMCPA was applied to agricultural crops . An average of about 10 million acres was treated annually, and the average application rate was 0.3 lbs
. a.i
. per acre. The average application rate stayed the same for the time periods, 1998

-2005 and 2006

-201 1
. Because the use in both pounds applied and area treated has been trending down, use in recent years is below the average reported above.

Page 3FIGURE 

### 1. MCPA T otal Area Treated in Acres & Total Pounds in Active Ingredient A lied (1998-2011) 14,000,000

Total Pounds App l ied & Total AcresTreate d ---- ··-·---

0 -------,....------..----.,---,.. ....., .**-· ---·-~-** **~ ~**  o**~** N m**~ ~** **~ ~** **~ ~**  o**~ ~** **~** 0 0 0 0 0 0 0 0 0 0**~ ~** **~ ~**  0 0 0 0 0 0 0 0 0 0 0 0**~ ~**  N N N N N N N N N N N N Years**BS**

.,._ TAT

·-----· -·---·-·- ------·- ..- ·-- ·---· ----' Source : Proprietary Data, 1998-20 1 1 2007-2011 From 2007 to 2011, an average of2 million pounds ofMCPA was applied annually to 8 mill ion acres at an average application rate of 0.25 lbs. a.i. per acre . Table 1 shows that the vast majority ofMCPA use is on wheat, with spring wheat accounting for more than half of the use both in terms of pounds appli ed and acres treated. Barley is the second most widely treated crop. Thirty percent of barley, 5 percent ofoats, and 1 5 percent of green peas are treated on average with MCPA, according to the 2013 Screening Level Usage Analysis (SLUA). The SLUA indicates that about 20 percent ofwheat acreage is treated with MCPA. Proprietary data (2007-201 1) show 37% of spring wheat and 4% of winter wheat are treated with MCPA, as shown in Table 1. Table 

### 1. Crops with Highest Use of MCP A- Percent of T otal Lbs Active Ingredient A
.

pplied and Total Area Treated (TAT) in Acres, 2007-2011 Crop Percent of Percent of Crop Percent of Total Pounds Treated Area Treated Applied Spring Wheat 60 37%a 64 Winter Wheat 25 4%a 23 Barley 12 30% 12 Green Peas 0.32 15% 0.35

Page 4Source: Proprietary Data, 2007-2011 a EPA ' s SLUA shows a percent crop treated on wheat between 20 and 40%, but does not distingu ish between spring and winter wheat. However, the percent crop treated can be approximated. If about 8 million acres are treated (see above), then if23% ofMCPA total acres treated are on winter wheat then about 1.8 million acres of winter wheat are treated. If 64% of acres treated are on spring wheat, then about 5 million acres of spring wheat are treated
. From 2007

- 2011, an average of42.5 million acres of winter wheat were planted annually, so about 4% ofthe winter wheat crop is treated. Over the same period, an average of about I 3
.4 million acres of spring wheat were planted annually , so about 37% ofthe spring wheat crop was treated with MCPA on average . Table 2 shows the states with the greatest use of MCP A. These states are concentrated in the Northern and Northwestern parts of the country, where wheat (especially spring wheat) and barley are common crops. The percent oftotal area treated in Montana is greater than the percent of poundage used, while the percent ofMCPA pounds used in Idaho is greater than the percent of total area treated. This implies that application rates are slightly higher than average in Idaho, and slightly lower in Montana. These differences in rates are likely due to the use of different formulations or to the use oftank- mixed products. 

### Table 2. Comparison of States with Highest Use of MCP A- Percent OfT ILb A 

## r d dT lA T t d' A 20072011 ota s. lPP.le an ota rea rea e ID 

### cres, 

# - State Percent of Pounds Percent Total Area Treated Applied North Dakota 34 34 Montana 16 18 Minnesota 13 13 Washington 10 10 Idaho 9 8 Source: Proprietary Data, 2007-2011 Table 3 shows that the average application rate was 0.3 lbs. a.i. per acre for the top crops. 

### Table 3. MCPA Use on Top Crops : Total Pounds Applied, Total Acres Treated and A I R 2007 2011**vera~e** 

### A
.. ate, 

## - Crop Pounds Applied, Total Acres Treated, Avg. AI Rate (lbs. Annual Average Annual Average a.i./acres) Spring Wheat 1,500 ,000 5,100,000 0.3 Winter Wheat 600,000 1,800,000 0
.3 Barley 300,000 1,000,000 0.3 Source: EPA Proprietary Data, 2007-2011 

### Geographic Distribution of MCPA USE 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 1000 acres of land in farms
. This differs from the application rate, which is expressed as the pounds a.i. applied per treated area. The average application rate of Page 50.3 lb a.i. per acre implies a rate of 300 lbs. a.i
. per I 000 treated acres. The maximum use intensity observed ranges from 31 lbs. to 45 lbs a.i. per 1000 acres of land in farms. Figure 2 spatially represents MCPA usage by crop reporting district for 2007-2011. Use is widespread across the US , probably reflecting use on wheat which is grown in many areas. The highest use intensity is across the North ofthe country, reflecting a concentration of use on wheat and barley in the Great Plains and in Eastern Washington and Idaho
. For more information on the use of the included map, see Appendix A
.

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### FIGURE 2. MCPA Use by 

### Crop Reporting District (2007-2011)

Average Pounds Per 1,000 Acres of Farmland

- 0-3

- 4-9 

## D 1o-1s

- 19-30

- 31-45 

### 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. Pesticide usage is displayed as average pounds (for the years 2007-2011) per 1,000 acres of farmland in a CRD to normalize for the variation in farmland between CRDs. Farmland acreage was obtained from US DA (2007). Farmland or " land in farms " is defined as fo llows: 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 Page 7

### CRP, WRP, FWP, and CREP 1 

### 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 non-Native 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 (USDA, 2007). Usage is based on private market surveys of pesticide use in agriculture (Proprietary Data, 2007-2011)
. The survey data are limited to the states that represent the top 80

- 90percent 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 t he CRD. This map displays ratio data (i
.e . , average pounds per 1 ,000 acres of farmland) summarized at a very high-level. Readers are strongly caut ioned against trying to over in terpret 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 chemica l 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. Non-Agricultural 

### Usage The available data on MCPA use on non-agricultural sites show changes, but not in a consistent direction. Use ofMCPA on golf courses and institutional turf increased substantially from 2004 to 2006 (Table 4). Combined, these two sectors show a ten-fold increase in use in only two years, with two-thirds of the increase in use from institutional turf. The use on landscape decreased drastically from 38,000 lbs. a.i. in 2002 to 2 ,000 lbs. a.i
. in 2006. The largest use of

1 CRP : Conservation Reserve Program; WRP: Wetland Reserve Program; FWP: Farmable Wetlands

### Pr~gram;

CREP: Conservation Reserve Enhancement Program

### Page 8this chemical on grass and turf was by lawn care operators (LCOs). This use in 2006 was less than half of what was used in 2002, as shown in Table 4. Most ofthe decline happened between 2002 and 2004. The most recent 2011 non-agricultural use ofMCPA is 1.3 million lbs. a.i. used in consumer lawn herbicides, mostly in combination with other active ingredients. 

### Table 4
. MCP A Non-Agricultural Use Segment/Site 2002/lb. a.i. Golf Courses · NIA Institutional Turf NIA Landscape 38,000 Lawn Care Operators (LCOs) 642,000 Nurseries/Greenhouses N/A Source: Kline and Company, Inc., 2002,2004, and 2006 Data are not available for the cells with N/A 

### CHEMICAL AND USE CHARACTERIS TICS 2004/lb. a.i. 2006/lb. a.i. 5,000 21,000 1 ,000 41,000 32,000 2,000 276,000 283,000

N/A <500

MCPA herbicide controls annual and perennial broadleafweeds. According to the Weed Science Society of America mechanism of action classification, MCPA belongs to the Group 4 herbicides (family of synthetic auxins). It is a selective, post-emergent, systemic herbicide and available as a single active product or in mixtures. For best weed control, weeds should be sprayed when they are actively growing and at their most susceptible stage. For example, annuals should be sprayed when young and perennialsjust prior to appearance of bud stage. Ester formulations of MCPA have a higher volatility than other formulations. Therefore, at high temperatures, application of ester formulations can damage the sensitive non-target plants around the application site (Herbicide Handbook, 2003). Furthermore, the presence ofbiotypes of9 weed species with resistance to the group 4 herbicides has been reported in the United States. Among them prickly lettuce 

### (Lactuca serriola) has shown resistance to 2,4-D, dicamba, and MCPA (Internationa l Survey of Herbicide Resistant Weeds, 2011 ). 

### ROLE OF MCP A IN PEST MANAGEMENT The major role of MCPA in pest management is wide use as a postemergence herbicide for selective control ofannual and perennial broadleafweeds in many agricultural and non-agricultural sites. Although BEAD has never evaluated the benefits of MCP A, the usage data shown in Table 1 highlights the value ofMCPA to wheat (especially spring wheat) and barley. These important use sites are referenced in BEAD's screening level usage analysis (SLUA) (USEPA 2013), which shows that up to 40 percent of the wheat crop (which includes both spring and winter wheat) and up to 40 percent ofthe barley crop may be treated with MCPA. The SLUA shows that MCPA may have an important role for smaller crops, with up to 20 percent of green peas treated, and up to 10 percent of oats. These shares ofcrop treated, however, are on smaller crops, so only about 8,000 pounds of MCPA were applied to green peas, and up to 100,000 on oats.
Page 9DATA NEEDS The Agency currently has usage data for most ofthe agricultural crops/sites for which MCPA is registered
. Usage data are unavailable on the small crops such as oats, rye, flax, and on nonagricultural use sites. BEAD has little information on use of MCP A and its importance in non- agricultural use sites
. Obtaining t he information on nonagricultural, uncultivated areas/soils and ornamental lawns and turf would improve future assessments conducted by the Agency related to the use and importance of MCPA. BEAD does not know why use on turf sites, such as golf courses and institutional turf have increased so substantively. Information on the value ofMCPA to these sectors, and an y changes in the controlled weed spectrum and information on the herbicides that can be used as alternatives to MCP A would be important to determine the value ofMCPA usage on turf and ornamental lawns. APPENDIX A The map included above is primarily for the use of the risk assessors in the Environmental Fa te and Effects Division. The map provides a very broad geographical view of the amount (in pounds) ofthe active ingredient applied per 1 ,000 acres of"land in farms ". These data are included in the maps because risk assessors are interested in the amount of a pesticide used across farmland. Because ofthe definition of Land in Farms, as discussed below, the calculated values presented in the map are not equivalent to an application rate (lbs. a.i. I a). The data used to make these maps have many limitations. Any interpretation ofthe maps should consider the underlying data and the associated limitations carefully. The smallest areas shown on the maps within each state are Crop Reporting Districts (CRD). CRDs are defined by USDA and each consists of multiple counties that have similar soils, growing conditions, and farming practices. The CRDs within many states have roughly the same area. Because it is not feasible to conduct an agricultural survey that samples every county in the United States, the use of CRDs allow for a sample to be collected that represent a much larger area with relatively homogeneous agricultural characteristics
. The numerator (annual average pounds applied) is based on priva te market surveys ofpesticide use in agriculture averaged over the last five years (Proprietary Data, 2007

-2011 ). These surveys cover about 60 crop s and are targeted in states that produce the majority of the crop. Although the surveys capture most of the use ofa part icular active ingredient in agriculture, there are several limitations to these surveys. States with minor production of a surveyed crop are not sampled Not all types of pesticides are surveyed in every crop in every year Many specialty crops with very small acreages are not included 

### in the survey
Page 10The result ofthese limitat ions is that CRDs that show no usage may actually have a sma ll amount of the active ingredient being used. The denominator (1 ,000 Acres ofland in farms) was selected from the Census ofAgriculture (USDA , 2007) to repre sent agricultural acreage that is actively managed and includes most ofthe areas treated with pesticides. The category "Land in Farms" is defined by the Census of Agriculture as being made up of four components: • Total cropland • Permanent pasture • Total woodland • Land in farmsteads, bui ldings, livestock faci lities , ponds , roads, wasteland, etc. This category includes land in the various USDA conservation programs . It should be noted that the Census of Agriculture does not include grazing land rented (on a per-animal basis) from the Bureau of Land Managemen t or Forest Service, thus it is an underestimate ofthe land being managed for agricultural purposes. 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 . 

### REFERENCES: Grube, A H. 2008. Usage Report Package in Support of Regi s tra tion Review for the Herbicide MCPA, (03051), BEAN DP #: 352641, Decision#: 38254. Herbicide Handbook. 2003. Guidance on the use ofherbicides on nature conservation sites, Sections 1-4
. MCP A
. Pp 91-92. http: / /publications.naturalengland.org.uk/publication/680 19
. Accessed on Nov. 18,2013. International Survey of Herbicide Resistant Weeds. 2011. http://www
.weedscience.com/surnmary/home.aspx
. Accessed on July 19,2013. Proprietary Data, 1998-2011. USDA, NASS. 2007-2010. Crop Reporting Districts
. Online: http ://www.ers .usda
. gov/briefmg/arms/resourceregions/resourceregions
.htm#nass
. Accessed on July 3 , 2013. USDA, 2007
. Census ofAgriculture
. Online: http: //www.agcensu s .usda.gov /Publications/2007/index.asp. Accessed on July 2 , 2013. USEPA. 2004
. EPA R.E.D
. Facts. MCP A. http ://www.epa. gov/ oppsrrd1 /REDs/factsheets/mcpa red fs.pdf. Accessed on July 9, 2013. USEPA. 2013
. MCPA Case (30501, 30502,30511,30516,30563, and 30564) Screening Level Usage Analysis (SLUA), Date: July 25, 2013. Page 11WSSA (Weed Science Society of America (WSSA), 201 1
. Summary ofHerbicide Mechanism of Action According to the Weed Science Society of America. http: //wssa.net /wpcontent/uploads/WSSA-Mechanism-of-Action.pdf. Accessed on July 17 , 2013
.

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