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<p>Office of Pesticide Programs (OPP) Conference Room 1126<br />
1801 S. Bell St. - Crystal Mall 2<br />
Arlington, VA  22202</p>

<p><strong>On this Page</strong></p>

<ul>
<li><a href="#attendees">Attendees</a></li>
<li><a href="#welcome">Welcome and Introductions</a></li>
<li><a href="#on">On-going Action Items</a></li>
<li><a href="#brief">Brief Updates</a></li>
<li><a href="#presentations">Major Presentations</a></li>
<li><a href="#additional">Additional Discussion</a></li>
<li><a href="#wrap">Wrap up</a></li>
</ul>

<hr />

<h2 id="attendees">Attendees</h2>

<table class="table zebra" summary="Attendees">
<thead>
<tr><th scope="col">Name</th><th scope="col">Association</th></tr>
</thead>
<tbody>
<tr><td>Betsy Behl</td><td>OPP/EFED	</td></tr>
<tr><td>Ron Parker</td><td> 	OPP/EFED</td></tr>	
<tr><td>Mark Corbin</td><td>	OPP/EFED</td></tr>	
<tr><td>Jim Lin</td><td>	EPA/EFED</td></tr>	
<tr><td>Nelson Thurman</td><td> 	EPA/EFED</td></tr>	
<tr><td>R. David Jones</td><td>	EPA/EFED</td></tr>	
<tr><td>James Hetrick</td><td>	OPP/EFED</td></tr>	
<tr><td>Lucy Shanaman</td><td>	OPP/EFED</td></tr>	
<tr><td>Roxolana Kashuba</td><td>	OPP/EFED</td></tr>	
<tr><td>Bill Eckel</td><td>	OPP/EFED</td></tr>	
<tr><td>ED Fite</td><td>	OPP/EFED</td></tr>	
<tr><td>Loren Hall</td><td>	OPP/EFED</td></tr>	
<tr><td>Ted Kuchnicki</td><td>	PMRA	</td></tr>
<tr><td>Mark Russell</td><td>	Dupont</td></tr>	
<tr><td>Kathy Carr</td><td>	Monsanto</td></tr>	
<tr><td>Ian Chart</td><td>	AMVAC</td></tr>	
<tr><td>Mary Nett</td><td> 	WQC</td></tr>	
<tr><td>Steve Cryer</td><td> 	DowAgro</td></tr>	
<tr><td>Ian van Wesenbeek</td><td>	DowAgro</td></tr>	
<tr><td>Pat Havens</td><td> 	DowAgro</td></tr>	
<tr><td>Russell Jones</td><td> 	BayerCropScience</td></tr>	
<tr><td>George Sabbagh</td><td>	BayerCropScience</td></tr>	
<tr><td>Paul Hendley</td><td> 	Syngenta</td></tr>	
<tr><td>Scott Jackson</td><td> 	BASF</td></tr>	
<tr><td>Uwe Wanner</td><td>	Crompton</td></tr>	
<tr><td>Joan Gaidoz</td><td>	Dynamac</td></tr>	
<tr><td>Tom Gilding</td><td>	CLA</td></tr>	
<tr><td>Dave Valcore</td><td>	Dow Agrosciences</td></tr>	
<tr><td>Greg Leyes</td><td>	ISKB</td></tr>	
<tr><td>Bob Butz</td><td>	Chem Rec Intl</td></tr>	
<tr><td>Mark Cheplick</td><td> 	Waterborne Environmental</td></tr>	
<tr><td>Cathleen Hapeman</td><td>	USDA/ARS</td></tr>	
<tr><td>Laura McConnel</td><td>	USDA/ARS</td></tr>	
<tr><td>David Sullivan</td><td>	Sullivan Environmental</td></tr>	
<tr><td>Rick Reiss</td><td>	Sciences International</td></tr>	
<tr><td>Natalia Peranginangin</td><td>	Syngenta</td></tr>	
<tr><td>Nancy Ragsdale</td><td>	USDA ARS</td></tr>	
<tr><td>Joe Albright</td><td>	EPA OPP</td></tr>	
<tr><td>Susan Hunter Yungsen</td><td>	Bergeson and Campbell</td></tr>	
<tr><td>James Cooper</td><td>	FL Dept of Agriculture</td></tr>	
<tr><td>Norman Birchfield</td><td>	EPA OPP</td></tr>	
<tr><td>Teleconference Link</td><td>	California DRP</td></tr>	
</tbody>
</table>

<p class="pagetop"><a href="#content">Top of page</a></p>
<hr />

<h2 id="welcome">Welcome and Introductions</h2>

<p>Ron Parker (OPP/EFED) chaired the meeting in the capacity of co-chair of the EFED Water Quality Tech Team (WQTT). The next two quarterly meetings will be chaired by Marietta Echevarria, the other co-chair. </p>

<p>This meeting includes presentations which focus on the topic of  "pesticides in air". Issues addressed are: </p>

	<ol>
	<li><p> field estimation and computer simulation modelling of pesticide 	volatilization from soil, </p></li>
	<li><p> pesticides in air and rain water samples and </p></li>
	<li><p> development and usage of pesticide spray drift models.</p></li>
	</ol>
 
<p>All FIFRA EMWG agendas, minutes and presentations and be found at: </p>
<p><a href="http://www.epa.gov/oppefed1/models/water/emwg_top.htm"> http://www.epa.gov/oppefed1/models/water/emwg_top.htm</a></p>

<p class="pagetop"><a href="#content">Top of page</a></p>
<hr />

<h2 id="on">On-going Action Items from Previous Meetings</h2>

	<ul>
	<li><p>NAFTA Guidance for Conducting Terrestrial Field Dissipation Studies will be 	added to the EPA website when complete and approved</p></li>
	<li><p>EFED will post revised surface water scenarios and list of those developed 	specifically for the OP cumulative assessment  </p></li>
	<li><p>ORD will post revised PRZM 3.12.2 on the CEAM website</p></li>
	<li><p>Information on PRZM 3.12.2 revised volatilization feature will be included 	in the description of model changes </p></li>
	</ul>

<p class="pagetop"><a href="#content">Top of page</a></p>
<hr />

<h2 id="brief">Brief Updates</h2>

	<ol>
	<li><p>QA/QC of Pesticide Root Zone Model (PRZM) Version 3.12.2 (J. Hetrick)</p>

	<p>EFED QA/QC team has looked at the emergence date and other variables to 	investigate a systematic error which had been seen in the output from the first 	year of runoff relating to planting date.  The detailed internal QA QC report on 	the new PRZM version is in progress. <strong>EFED will write up the issue for 	circulation and discussion on the list server. </strong></p>

	</li>
	<li><p>QA/QC of EXPRESS (R. Parker)</p>

	<p>The EXAMS-PRZM Exposure Simulation System (EXPRESS) and recently completed 	user's manual have been handed over by EFED contractor WEI to the ORD Center for 	Exposure Assessment Modelling (CEAM). CEAM is conducting a QA/QC review of the 	shell and revising the shell and user's manual where necessary. Revised versions of 	EXPRESS are posted on the CEAM website for testing and comment. </p>

	<p>EXPRESS should not yet be used for regulatory submission of exposure assessments 	but instead still needs to be compared with output of other approved tools (e.g. 	PE4 or stand-alone PRZM).  Ron asked everyone to send all comments and suggestions 	to both ORD and to himself.</p>

	<p>EFED is responsible for the scenarios used for modelling by the Agency, which 	are available in the EXPRESS shell. ORD is responsible for maintenance of the 	source code and for public availability. <strong>Betsy Behl agreed that EFED would 	circulate a list of key and supplementary PRZM/EXAMS scenarios via the list server.	</strong></p>

	</li>
	<li><p>Carbamate Cumulative Assessment (N. Thurman)</p>

	<p>The report resulting from the February 2005 Carbamate Cumulative SAP meeting is 	expected soon; EFED will send notification via the EMWG list server when it becomes 	available.  The SAP provided valuable feedback that EFED will take into account in 	its ground water modeling efforts for the carbamate cumulative. New scenarios are 	being developed for the ground water modeling work.</p>

	<p>Another SAP on the preliminary carbamate cumulative assessment will take place 	later this year, on the week of August 23-26. Based on that SAP and public 	comments, OPP expects to release the revised/final carbamate cumulative assessment 	by December.</p>

	</li>
	</ol>

<p class="pagetop"><a href="#content">Top of page</a></p>
<hr />

<h2 id="presentations">Major Presentations </h2>

<p>Four presentations were made on estimation of pesticide volatilization from agricultural fields. The first was a presentation on methods of conducting field studies for developing input parameters for computer simulation modelling of volatilization from soil. The other three presentations discussed use of individual volatilization models that have been created to develop a better understanding of the data and how it might be further processed to make it more useful in risk assessments. Each of the three was presented to an OPP Science Advisory Panel meeting in 2004.  </p>

<p>(<a href="http://www.epa.gov/scipoly/sap/2004/september/meetingminutessept04.pdf">http://www.epa.gov/scipoly/sap/2004/september/meetingminutessept04.pdf</a><br />
<a href="http://www.epa.gov/scipoly/sap/2004/august2/aug2004final.pdf ">http://www.epa.gov/scipoly/sap/2004/august2/aug2004final.pdf</a><br />
<a href="http://www.epa.gov/scipoly/sap/2004/august1/august24transcript.pdf"> http://www.epa.gov/scipoly/sap/2004/august1/august24transcript.pdf</a> ). </p>

<p><strong>All of the following talks will be posted on the EMWG website.</strong></p>

<p><strong>Presentation 1</strong>: Soil Fumigant Critical Input Parameter Selection for Air Dispersion Modeling, Ian van Wesenbeeck, Ph.D. - Dow AgroSciences</p>

<p>Summary: The goals of soil fumigant field studies and modelling are to develop a methodology to predict air concentrations for use in population-based risk assessment and to establish buffer distances. The modeling must account for variability in meteorological conditions and agronomic practices and include the incorporation depth, application type, rate and date. The study author's found that the flux profile is the most important input in air dispersion modeling because there is a direct correlation between flux rate and off-site concentrations. </p>

<p><strong>Presentation 2</strong>: Fumigant Exposure Modelling System (FEMS): David Sullivan - Sullivan Consulting</p>

<p>FEMS was developed with several goals in mind. These were to </p>

	<ol>
	<li><p> seek accuracy in exposure assessment, </p></li>
	<li><p> base distributions of exposure on plausible cultural practice, maintain 	mass balance, </p></li>
	<li><p> provide risk managers with results that consider uncertainty in all key 	inputs, and </p></li>
	<li><p> to have a firm basis to establish margin in risk assessment process.</p>	</li>
	</ol>

<p>FEMS is a Monte Carlo based assessment tool which is based on two EPA models:  ISCST3 & TOXST. It addresses issues such as </p>

	<ol>
	<li><p> the need to account for the number of applications per year, </p></li>
	<li><p> irregular geometry of commercial fields, </p></li>
	<li><p> need to realistically address cultural practices such multiple-day 	sequential applications, </p></li>
	<li><p> need to address calm periods and </p></li>
	<li><p> recognizes that different seasonal issues need to be considered by region 	and by crop. </p></li>
	</ol>

<p><strong>Presentation 3</strong>: Probabilistic Exposure and Risk model for FUMigants (PERFUM): Rick Reiss D.Sc. - Sciences International</p>

<p>The presentation included four elements:</p>

	<ol>
	<li><p> a description of the fumigant bystander exposure issue, </p></li>
	<li><p> a description of the PERFUM model, </p></li>
	<li><p> a demonstration of PERFUM with generic examples, and </p></li>
	<li><p> a discussion of the upper tail of the exposure distribution. </p></li>
	</ol>

<p>The PERFUM approach is to </p>

	<ol>
	<li><p> run ISCST3 with 5 years of historical meteorological data,</p></li>
	<li><p> generate a 5-year set of daily average concentrations (which is different 	than for a continuously emitting source), </p></li>
	<li><p> estimate concentrations in all directions around the field to develop the 	exposure probability and </p></li>
	<li><p> use the measured diurnal profile of flux rates in estimating exposure. </p>	</li>
	</ol>

<p>PERFUM capabilities: </p>

	<ol>
	<li><p>Can input up to 15 days of flux data after the application and then models 	the changes in the buffer zone distributions with time since application and 	produces buffer zones for all distributions for each averaging period and each 	toxicity averaging time,</p></li>
	<li><p> Has a batch file system for multiple runs and can run up to 10 application 	rates simultaneously; this requires very little additional processing time for 	additional rates and is useful for developing buffer zone tables, </p></li>
	<li><p> provide outputs buffer zones on a monthly basis for seasonal analysis, 	yields a contour file which allows the whole field buffer zone to be plotted on a 	site map and has about 80 error messages to assure properly formatted input data 	and proper execution.</p></li>
	</ol>

<p><strong>Presentation 4</strong>: Predicting Soil Fumigant Acute, Sub-chronic, and Chronic Air Concentrations Under Diverse Agronomic Practices: An overview of the SOFEA(c) System, Steve Cryer, Ph.D. - Dow AgroSciences</p>

<p>SOFEA possesses an intelligent input file generator and output depository for agronomic use of Gaussian Plume models.  It uses MS Excel as a Graphical User Interface and includes Crystal Ball 2000 Pro for stochastic functionality (Monte Carlo). It combines a number of features:</p>

	<ol>
	<li><p> simulation of a variety of agronomic practices, </p></li>
	<li><p> use of GIS representations of data, </p></li>
	<li><p> complex spatial analysis, and</p></li>
	<li><p> exceedence probabilities format for outputs.</p></li>
	</ol>

<p>SOFEA capabilities are as follows:</p>

	<ol>
	<li><p> It automates complex process for developing inputs, executing, and 	summarizing necessary inputs for USEPA air dispersion model, </p></li>
	<li><p> It allows specification of up to 5 different unique cropping patterns, </p>	</li>
	<li><p> fields can be either randomly placed within township or by section 	weighting and the percent of field re-treatment from year to year is user-	specified,</p></li>
	<li><p> It permits heterogeneous variable township use, </p></li>
	<li><p> It provides an option to incorporate GIS data,</p></li>
	<li><p> It includes land use, population, elevation and regionally specific weather 	patterns, </p></li>
	<li><p> It permits the possibility of forecasting along with BMP "what-	if" simulations, </p></li>
	<li><p> the system is written entirely in VBA (with exception of ISCST3 and one 	FORTRAN optimization module) and runs on a standard PC that has sufficient memory 	and disk space, </p></li>
	<li><p> has a solid Framework for easy expansion of functionality, and </p></li>
	<li><p> the results are of the same order as large-scale monitoring observations	</p></li>
	</ol>

<p><strong>Presentation 5</strong>: Environmental and Agricultural Factors Controlling Pesticide Volatilization, Transport, and Deposition - Laura McConnell, Ph.D. USDA/ARS Beltsville, MD</p>

<p>Dr McConnell's presentation included </p>

	<ol>
	<li><p> a description of chemical factors influencing volatilization, </p></li>
	<li><p> a summary of atmospheric transport and deposition processes, </p></li>
	<li><p> results from work in the Chesapeake Bay region for both pesticides and 	Polybrominated Diphenylethers (PBDEs) and </p></li>
	<li><p> a look at new directions in the work.</p></li>
	</ol>

	<p>Volatilization is important for several reasons: </p>

	<ol>
	<li><p> active ingredient moves off-target, reducing product effectiveness,</p>	</li>
	<li><p> potential human health risk to workers and nearby residents, and</p></li>
	<li><p> increases exposure to sensitive wildlife populations.</p></li>
	</ol>

<p> Factors effecting availability for volatile loss include: </p>

	<ol>
	<li><p> affinity for organic carbon; octanol/water partition coefficient (K<sub>ow	</sub>) reduces leaching in high OC soils, </p></li>
	<li><p> strong and weak molecular interactions with soil surfaces; this is 	generally more important under dry soil conditions, </p></li>
	<li><p> susceptibility to microbial degradation in soil which generally increases 	with repeated applications and </p></li>
	<li><p> photodegradation, which is only important for photosensitive chemicals at 	soil or plant surface. </p></li>
	</ol>

<p>Persistence in the atmosphere is governed by </p>

	<ol>
	<li><p>susceptibility to direct or indirect photoreactions, i.e. hydroxyl radical 	(OH), nitrate radicals (NO<sup>3</sup>), or ozone (O<sup>3</sup>), </p></li>
	<li><p> octanol/air partition coefficient (KOA) which governs vapor-particle 	partitioning, </p></li>
	<li><p> Henry's law constant, </p></li>
	<li><p> particulate concentrations in air and </p></li>
	<li><p> frequency of precipitation events.</p></li>
	</ol>

<p>The presentation described detection in rainfall and detections in air for several chemicals in relationship to agricultural activity in the Delmarva Peninsula.</p>

<p>Upcoming work includes </p>

	<ol>
	<li><p> developing tools to predict atmospheric fate of VOC and odorant emissions 	from agricultural operations, </p></li>
	<li><p> determination of ozone creation potentials for pesticide formulation 	products and emissions from animal operations based on atmospheric chemical 	reactivity, and </p></li>
	<li><p> transfer this information to customer groups for use in the development of 	improved air quality management strategies. </p></li>
	</ol>

<p><strong>Presentation 6</strong>: EFED Spray Drift Modeling Activities: Norm Birchfield, Ph.D - OPP/EFED</p>

<p>An EFED specific model, RegDISP is being developed by Milt Teske at Continuum Dynamics and a beta version is already in house at EPA; QA/QC will be conducted later.  This shell does not have all the tools available in AgDISP and/or AgDRIFT and has a simple appearance.  The options available to the user include those that would be expected to be used most frequently in typical screening-level spray drift assessments.</p>

<p>This interface will provide another front end option for drift models using the AGDISP core computational code; however, there are no plans as yet for this to become the sole interface.  Norm stated that EFED will continue to leave options open for selection of models for use in spray drift related exposure assessments.  The best model for the assessment at hand should always be used. </p>

<p>Norm then discussed the "mechanistic" ground boom model which was recently incorporated into AGDISP version 8.13.  The new ground boom model was adapted from the Lagrangian approach used in the aerial parts of AGDISP and AgDRIFT but without some of the aircraft wake aspects.  The new ground boom model has been shown to compare well with the SDTF field data; but Norm has some concerns that there is some temperature dependence leading to over-prediction at low temperatures.  Comparisons of the predictions of the mechanistic ground boom model with Tom Wolfe's Canadian drift data and the European data sets are planned.</p>

<p>Norm also announced that work has been under way to link the new RegDISP interface to the EFED PE4 shell, creating a PRZM/EXAMS/RegDISP interface.  This new interface offers options to add application efficiencies and drift values directly into the PRZM input files. New interface offers option to use daily wind speed /direction, temperature and RH as specified for the application day for each simulation.  A QA/QC process will precede any use of this version of PE4. Norm commented that this linkage is also expected to be developed for the EXPRESS shell.  <strong>EFED will discuss progress and implications at the next meeting.</strong></p>

<p><strong>Presentation 7</strong>: Drift Reducing Technology Project: Norm Birchfield</p>

<p>This presentation was authored by Norm B.; Jay Ellenberger and Gregory Sayles.  The Drift Reducing Technology project is an ORD-lead proposal to look at "what is needed to promote increased use of drift-reducing technologies (or DRTs)".  The project involves better understanding barriers to the use of DRTs and developing a process to overcome these barriers.  Proposed efforts include identifying/developing methods to verifying and quantify the drift reduction potential associated with the use of DRTs, the development incentives for DRT use on product labels, economic analysis of DRT use, and development of a technology transfer plan. </p>   

<p>In a test pilot study for the DRT process air-assisted boom sprayers were identified as a promising DRT.   The rational for using air-assisted boom spraying (AABS) system included: </p>

	<ol>
	<li><p> relatively large body of performance data currently available, </p></li>
	<li><p> several companies produce AABS-type systems in the U.S., and AABS is a 	commonly used, economically viable DRT in Europe, but not in common use in U.S. 	</p></li>
	</ol>

<p>Potential benefits of using DRTs include: </p>

	<ol>
	<li><p> greater flexibility to ground applicators to meet or improve on drift 	requirements, </p></li>
	<li><p> may lower overall costs of spraying, </p></li>
	<li><p> supports private-sector technology development, </p></li>
	<li><p> minimizes impact of spraying on humans and ecosystems.  </p></li>
	</ol>

<p>A draft DRT process has already been constructed, and a feasibility test of the DRT process using AABS is planned, but will require in-kind and real funding.</p>

<p><strong>Presentation 8</strong>: AgDrift/AgDisp Modeling Issues: Dave Valcore, Ph.D. - Dow AgroSciences</p>

<p>The goal of the Spray Drift Task Force (SDTF) is to complete a final AgDRIFT regulatory version by 2006. Leadership is currently being transferred to Crop Life America (CLA) for drift modeling. Tom Gilding (of CLA) pointed out that he would be the point of contact for Industry responses on drift "issues" on behalf of the CLA Spray Drift Issues Team. User issues include</p>

	<ol>
	<li><p> bugs and glitches in both AgDRIFT 2.05 and AGDISP,</p></li>
	<li><p> details of version control and overall regulatory use of drift models, </p>	</li>
	<li><p> the AGDISP ground model, and </p></li>
	<li><p> question on science, validation bias, peer review, use in exposure 	assessments, ground model higher tier assessments, public stakeholder input, the 	USFS sponsored discussion session for planning future of drift modeling, a research 	/development version, the impact of and EPA DRT testing program, issues with Dept 	Home Security, release requirements and the need for a joint AGDISP/AgDRIFT 	security review. </p></li>
	</ol>

<p>The AgDRIFT website user version is AGDISP 8.03. </p>

<p>Future issues with the orchard option include:</p>

	<ol>
	<li><p> additional use patterns, </p></li>
	<li><p> a expanded database, </p></li>
	<li><p> higher tier and mitigation options,</p></li>
	<li><p> LERAP type approaches, and </p></li>
	<li><p> UK PACE vs TRV (tree row volume labeling). </p></li>
	</ol>

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<hr />

<h2 id="additional">Additional Discussion</h2>

<p>There is increasing concern of some industry modellers that once the scenarios are all working as intended (in terms of model input and soil related parameters), the output for erosion at certain sites can be seen to be developing unrealistic and unsustainable levels of erosion.  <strong>Industry will comment further via the listserver on the potential for over-prediction of erosion in certain standard scenarios</strong></p>
 
<p><strong>New Actions</strong></p>

	<ul>
	<li><p>EFED will post the list of standard and OP-only surface water modelling 	scenarios</p></li>
	<li><p>EFED will notify listserver when the Carbamate Cumulative SAP report becomes 	available</p></li>
	<li><p>EFED to make all air-related presentation materials available over EMWG 	webpage</p></li>
	<li><p>EFED will provide update on RegDISP interface to modelling shells at the 	next meeting</p></li>
	<li><p>Industry will comment via EMWG listserver on erosion predictions</p></li>
	<li><p>All will suggest topics for next meeting</p></li>
	</ul>

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<hr />

<h2 id="wrap">Wrap-Up: Next Meeting</h2>

<p>The group agreed that the next meeting should be held on Monday July 11<sup>th</sup>, 2005 with a strong plea to try to move it to Tuesday or Wednesday of that week (due to convenience for those who have to travel in the night before the meeting).  However since then an alternative date of Thursday 21<sup>st</sup> is being suggested as a way of avoiding the Monday meeting problem.</p>

<p><strong>(Subsequent to the meeting , the next meeting date has been finalized as July 21, 2005)</strong></p>

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