Washington State University FEQL Project No Food and Environmental Quality Laboratory Page 1 of 90 ANALYTICAL SUMMARY REPORT

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1 Food and Environmental Quality Laboratory Page 1 of 90 ANALYTICAL SUMMARY REPORT Temperature Dependent Emission Loss of MITC Following Surface Application of Metam Sodium Authors Jane LePage Vincent Hebert Analytical Laboratory Washington State University Food & Environmental Quality Laboratory 2710 University Drive Richland, WA Study Sponsor Washington State Potato Commission Study Timetable Experimental Start Date: 4/29/2010 Experimental Termination Date: 6/3/2010 Report Date: 6/23/2010

2 Food and Environmental Quality Laboratory Page 2 of 90 LOCATION OF RAW DATA The original raw data, protocol, correspondence logs, and all relevant information for the study titled, Temperature Dependent Emission Loss of MITC Following Surface Application of Metam Sodium, FEQL project number 0809, along with a certified copy of the signed analytical summary report will be maintained by the testing facility for a period of five years. Laboratory Research Director : Testing Facility: Dr. Vincent Hebert Food and Environmental Quality Laboratory Washington State University 2710 University Drive Richland, WA CERTIFICATION The undersigned hereby declares that this study was performed according to the procedures described herein, and that this report provides a true and accurate record of the results obtained. Laboratory Research Director Dr. Vince Hebert, Food and Environmental Quality Laboratory Washington State University, Tri-City Campus, Richland WA June 23, 2010 Date: System design and analytical work performed by: Elizabeth Culbert, Laboratory Supervisor Vince Hebert, Laboratory Research Director Jane LePage, Research Analyst

3 Food and Environmental Quality Laboratory Page 3 of 90 TABLE OF CONTENTS Page Executive Summary 4 Reference Citations 7 I. Objective/Introduction 8 II. Sample Inventory 8 A. Sample History 8 B. Storage Stability 9 III. Standard Preparation 9 IV. Procedure 10 A. Application and Air Sampling 10 i. Soil Column Preparation ii. Incubation iii. Fumigant Application iv. Air Sampling B. Modifications to the Protocol 13 C. Working Analytical Method 13 D. Quantification 14 i. Instrumentation ii. Calculations E. Method Validation and Analytical Limits 16 F. Interferences 17 G. Confirmatory Techniques 17 H. Time Required for Evaluation 17 V. Results and Discussion 17 Tables Figures Table 1: Incremental Temperature Evaluations 9 Table 2: Method Validation and Concurrent Fortification Results 19 Table 3: Soil Column Fortification Results 19 Tables 4-9: Sample Results Figure 1: Measured MITC flux at incremental soil column temperatures 5 Figure 2: Cumulative MITC emission at incremental soil temperatures 6 Figure 3: Incubation temperature control, air sampling units, and soil column apparatus 11 Figures 4-9: Air/Soil Temperature Profiles APPENDIX A. FEQL Project Protocol 53 APPENDIX B: Sample Inventory & History 61 APPENDIX C. Representative Chromatograms 82

4 Food and Environmental Quality Laboratory Page 4 of 90 Executive Summary Center-pivot chemigation and soil-incorporated shank injection are the principle means for applying metam sodium (MS) in large-scale potato production in the Pacific Northwest (PNW). Field fumigations occur during the cooler late fall-early spring months in moist soil (i.e., between 50 to 85 % of field capacity) with 1-inch of water to spatially set the product in the soil. The cooler seasonal application timing, soil preparation, and amount of water at application aid in retaining methyl isothiocyanate (MITC) within the soil while minimizing airborne off-target emissions. The current MS label allows applications by spray/incorporation, shank injection, drip, sprinkler, and flood irrigation at rates up to 75 gallons/acre (GPA). Typically, MS is applied at gal/acre rates for control of soil-borne pathogens in this region. Starting in 2005, MS along with other methyldithiocarbamate salts underwent a reregistration review overseen by EPA Office of Pesticide Programs (EPA-OPP or Agency) leading to the Reregistration Eligibility Decision (RED) for Methyldithiocarbamate Salts Metam Sodium/Potassium and MITC (USEPA, 2008a). Because of the absence of specific PNW regional field MITC emission rate (volatilization flux) information, the Agency relied on emission data from smaller acreage row crop summer application studies in southern California to model field edge buffer zones for larger acreage field crop fumigations in the PNW. These field emission data sets are limited in their utility because they provide MITC emission rate model estimates only for the specific conditions under which the studies were conducted. Based on regionally greater field acreage and differences in chemigation practices specific to the PNW, the currently used RED modeled emission data can result in appreciable field-edge buffers that may be overly conservative. The EPA-OPP has stated in the fumigant RED that site-specific buffer zones would provide the most flexibility for users but did not have sufficient data to support this scheme. To address the need for regional MS fumigant emission information, two Washington State field emission studies have been submitted to the Agency in 2009 and Herein, we are providing results from a laboratory-based examination of the influence of incremental soil temperature on MITC surface emission rates and cumulative loss over a two-day application-post application time frame. A sandy loam soil (sand 85%; silt 11%; clay; 4% with 0.7% organic matter) was collected from a non-fumigated section of a center-pivot circle which has been in potato production during the growing season and was used for this series of incremental temperature evaluations. This soil type is representative of potato production regions in eastern Washington State. The field collected soil was air-dried then sieved though 2 mm. To negate the possible influence of microbial degradation, the sieved soil was sterilized by autoclaving according to procedures outlined in Zheng et al Replicate stainless steel columns were specifically developed to ascertain differences in MITC emissions over a range of soil/air temperatures from 35 o F through 90 o F under controlled laboratory temperature conditions. Each column consists of two sections: a lower 20 cm length (3,395 cm 3 ) section that contained ca. 4 kg of uniformly packed moistened soil (1.18 g/cm 3 bulk density) and an upper 5-cm headspace section comprising 20% of the total column volume (ca. 850 cm 3 ). After soil preparation, the four soil columns (3 replicate treatments and 1 background control) were placed in a controlled temperature system and allowed to equilibrate with air temperature ca. 12 hours before fumigant addition. Immediately after the soil surface addition, the upper and lower column sections were sealed and air was continuously collected from the

5 Food and Environmental Quality Laboratory Page 5 of 90 upper column head space on activated charcoal at a rate of ca. 300 ml/min. Air collections were conducted ca. 2-hours pre-application, after application, and through hours postapplication. After air collection, the activated charcoal cartridges were solvent extracted with 20% carbon disulfide in ethyl acetate then analyzed for MITC by gas chromatography using nitrogen-phosphorus specific detection (NPD). The flow-through soil column design was found to be rugged in effectively quantifying MITC emissions from the column head space at all incremental temperatures. The average MITC recovery from laboratory fortifications performed with each analytical sample set was 97 ± 9.2% (n=63). The overall average recovery from activated charcoal fortified with a known amount of MITC and concurrently sampled through the soil column outlet for all incremental temperature series was 99 ± 15% (n= 35). All simulated fumigant surface applications were performed at the maximum product use rate of 75 GPA and at a soil field moisture capacity of ca. 80%. An equivalent of 1-inch water was administered at dosing to each replicated soil column. These soil column application conditions were chosen to closely approximate label requirements for field applications of metam sodium. Figure 1 presents a comparison of MITC air emission rates at the six laboratory controlled incremental temperatures over the 2-day experimental time frame. Figure 1: Measured MITC flux at incremental soil column temperatures. Indicated temperatures are 5-minute averaged controlled system values for the 48-hour 35, 40, 45, 55, 70, and 90 degree soil column evaluations. The collected data shows conversion time of MS to MITC, product soil retention, and subsequent MITC air emissions are highly dependent on soil temperature with this agricultural

6 Food and Environmental Quality Laboratory Page 6 of 90 soil at product label application conditions. Maximum MITC air concentrations were observed to occur within the 1-2 hour interval sampling period for the 90 o F series whereas maximum MITC conversion occurred over a 4-8 hour sampling period for the cooler soil column temperatures examined. This rapid abiotic conversion under laboratory conditions was anticipated based on our experiences and previous reported studies of metam sodium in soil (Smelt and Leistra, 1974). Preliminary soil column experiments by Zheng, 2006 conducted at laboratory room temperature also showed the transformation of MS to MITC being complete within 0.5 hours. The measured MITC surface emissions after conversion of MS to MITC approximated first order behavior at all observed temperatures (r ). MITC half-lives estimated after maximum MS conversion for each incremental temperature experiment ranged over seven-fold from 2.5 hours at 90 o F to ca. 18 hours at the cooler soil column temperatures. Figure 2 presents total MITC released over time for each incremental temperature during the 2- day period. Cumulative emission losses are expressed as a percentage of total applied fumigant (assuming 100% conversion of MS to MITC). Figure 2: Percent of total MITC emission at incremental soil column temperatures. Indicated temperatures are averaged soil temperatures for the 35, 40, 45, 55, 70, and 90 degree soil column evaluations.

7 Food and Environmental Quality Laboratory Page 7 of 90 The cumulative loss of the total applied was observed to be temperature dependent where, after 12 hours, ca. 20% of the soil-applied MITC was released to the air at ca. 35 o F while ca. 50% was lost from the soil column at ca. 90 o F. It is assumed that the percent of the total applied not accounted in the air was retained within the treated soil. The cumulative loss data for each temperature increment was kinetically well behaved based on increased MITC conversion rate and vapor pressure with temperature. The stabilization in loss for MITC in the 70 o F data set after 8 hours in comparison to other incremental temperature cumulative losses cannot be explained. After ca. 24 hours, volatile MITC emissions at all temperatures were appreciably attenuated (i.e., < 50µg/m 2 /sec). There have been few studies in the peer-reviewed literature that have comprehensively assessed the temperature dependence of MITC loss from soil after MS application. Ma et al. (2001) provided temperature comparisons of MITC degradation from 20 o C (68 o F) through 40 o C (104 o F) in sterilized and non-sterilized soils and suggested that microbial degradation was a major dissipation pathway. This current study on sterilized soil demonstrates that soil temperature during and shortly after MS application is a principal factor controlling fumigant retention in soil and volatilization of MITC under field application conditions. The Agency has based its fumigant risk mitigation decision on a flexible approach which is protective to bystanders and allows users to make site-specific choices to reduce potential impacts (USEPA, 2008b). A 10% field set-back credit has been granted for applications conducted at 70 o F or below less when measured at a soil depth of 3 inches for all fumigant applications. This set-back credit was developed with site-specific field volatility studies that were generated during warmer summer-time fumigation conditions with maximum air temperatures between F and/or maximum soil temperatures between F. This study supports greater flexibility than the current 10% set-back credit should be considered when specifying field buffer zones for MS applications conducted during cooler soil application temperatures typical of PNW soil fumigations. All raw data (in Excel format) used in the construction of this analytical summary report can be found at Referenced Citations: Ma Q.L., Gan J., Papiernik S.K., Becker J.O., Yates S.R Degradation of soil fumigants as affected by initial concentration and temperature. J. Environ. Qual : Smelt, J.H. and M. Leistra Conversion of metham-sodium to methyl isothiocyanate and basic data on the behavior of methyl isothiocyanate in soil. Pesticide Sci. 5: USEPA 2008a. Reregistration Eligibility Decision (RED) for Methyldithiocarbamate Salts Metam Sodium/Potassium and MITC July 9, USEPA 2008b. Factors Which Impact Soil Fumigant Emissions - Evaluation for Use in Soil Fumigant Buffer Zone Credit Factor Approach, Health Effects Division: 7905P, June 9, pp. Zheng W, S.R. Yates, Papiernik S.K., Nunez J Conversion of metam sodium and emission of fumigant from soil columns. Atmos. Environ

8 Food and Environmental Quality Laboratory Page 8 of 90 I. Objective/Introduction This project examined the soil surface emission rate of methyl isothiocyanate (MITC) at incremental temperatures under controlled laboratory conditions. Soil columns were prepared at typical field moisture conditions and equilibrated at the testing temperature. The soil was then treated with Sectagon 42 (metam sodium) at an application rate equivalent to 75 gallons per acre (GPA) and the MITC emission was monitored over a ca hour period to measure the fumigant emission rate. Replicate stainless steel columns were designed and used for these evaluations. Each column consisted of 4 kg of sterilized soil at a uniform moisture content and an upper headspace approximately 20% of the column volume. The columns were capped and air was collected over the surface of the soil at 300 ml/min using SKC-PCXR3 air sampling units. MITC surface emissions were continuously measured by collecting MITC air concentrations on activated charcoal. MITC residues were extracted from the charcoal and analyzed by gas chromatography using nitrogen-phosphorus specific detection (NPD). Detected MITC concentrations were compared to external standards by linear regression to calculate air concentrations for each sample interval. The complete project protocol, including individual lab methods, is provided in Appendix A. The Food and Environmental Quality Laboratory (FEQL) at Washington State University performed these evaluations and analyses to ascertain the significance of soil temperature on MITC fumigant surface emissions. This work was funded by the Washington State Potato Commission. II. Sample Inventory A. Sample History Incremental temperature evaluations were conducted from April 29 to May 27, Six temperature evaluations were performed for this study. For each evaluation there were three treated soil columns, A, B, and C, and one control soil column, D. Initially, a 2-hour preapplication chamber air sample was taken from each column. Then following fumigant application, air samples were taken continuously at two-hour intervals for a minimum of 48 hours post application (ca. 100 samples per evaluation). For the 90 F evaluation, sample intervals were one hour duration (196 samples). At the end of each sample interval, all samples were immediately placed in frozen storage (-80 C or -20 C) until analysis. Table 1 lists the dates for each soil column temperature evaluation. Tables B1-B6 of Appendix B include sample inventory and extraction history for the project.

9 Food and Environmental Quality Laboratory Page 9 of 90 Evaluation Target Temperature Table 1: Incremental Temperature Evaluations Average Soil Metam Application End of air sampling Temperature ( F) /29/2010 4:30 PM 5/1/2010 8:30 PM /4/2010 9:05 AM 5/6/2010 9:00 PM /11/2010 8:05 AM 5/13/ :00 PM /16/2010 9:10 AM 5/18/2010 9:00 AM /20/ :00AM 5/22/ :00 AM /25/ :00 PM 5/27/ :00 PM 1 Soil temperature averaged over the hour incremental temperature time frame. B. Storage Stability A storage stability evaluation for MITC on charcoal-filled glass cartridges was completed by the FEQL in 2005 (MITC Community Air Assessment. Analytical Summary Report, FEQL-NG- 0605). MITC was found to be stable on the cartridges stored at -80 o C for a period of 85 days. For this air monitoring project, no air sample cartridges were stored at 80 C for more than 17 days. Samples were typically extracted and analyzed within a week of sampling. Because of the higher water evaporation rate in the 90 F soil temperature evaluation, and therefore higher moisture in the sample cartridge, the 90 F samples were analyzed soon after sampling. III. Standard Preparation Sectagon 42 TM [42% sodium methyldithiocarbamate (metam sodium)] was used for all soil fumigant applications. Tessenderlo Kerley provided the 500 ml of the formulated testing material used in this study. A dosing solution equivalent to 75 gallons per acre Sectagon 42 was applied to each test chamber. The application solution was prepared individually for each soil column by adding 1.2 ml Sectagon 42 to 100 ml deionized water. This solution was prepared immediately before use. MITC reference substance (Cat. #MET-221A; Chem Service, West Chester PA) was used by FEQL for laboratory fortification solutions and analytical standards. The following substances, standards, and standard dilutions were prepared for this study: Test substance Compound Substance No. Lot No. Purity Source Sectagon 42 (metam sodium) 1393 not specified 42.2% TK Methyl isothiocyanate B 99.5% Chem Service Stock Solution Compound Substance No. Conc. Solvent Methyl isothiocyanate mg/ml ethyl acetate

10 Food and Environmental Quality Laboratory Page 10 of 90 Fortification Solutions Compound Substance No. Conc. Solvent Methyl isothiocyanate mg/ml ethyl acetate Methyl isothiocyanate mg/ml ethyl acetate Methyl isothiocyanate mg/ml ethyl acetate Linearity Standards Compound Substance No. Conc. Solvent Methyl isothiocyanate μg/ml 20% CS 2 /ethyl acetate Methyl isothiocyanate μg/ml 20% CS 2 /ethyl acetate Methyl isothiocyanate μg/ml 20% CS 2 /ethyl acetate Methyl isothiocyanate μg/ml 20% CS 2 /ethyl acetate Methyl isothiocyanate μg/ml 20% CS 2 /ethyl acetate Methyl isothiocyanate μg/ml 20% CS 2 /ethyl acetate The Sectagon 42 solution was stored at ambient temperature in a flammables cupboard. The reference substance was stored in a freezer (I.D. Dancer). All prepared stock, fortification, and linearity standard solutions were stored in the freezer at approximately 20 C (I.D. Prancer). The expiration date for the reference substance is 10/2013. The expiration date of the MITC standards is 4/29/2011. Dilutions are recorded in the FEQL analytical laboratory standards logbook. IV. Procedure A. Application and Air Sampling i. Soil Column Preparation Four stainless 25 cm length by 14.7 cm diameter stainless steel column cylinders were constructed for this study (Figure 3). Each column consists of two sections: a lower 20 cm length (3,395 cm 3 ) section to contain ca. 4 kg moistened soil and an upper 5-cm length headspace section comprising 20% of the total column volume (ca. 850 cm 3 ). The lower 20 cm chamber section of each column was uniformly packed with soil to a depth of ca. 19 cm. The lid of the chamber was then clamped into place to form the headspace of the column. Each upper chamber section was constructed with ports for air inlet and outlet at 180. Thermocouple probes were positioned for mid-column and headspace temperature monitoring. An O-ring/ clamping assembly was employed to provide an airtight seal. Teflon tubing was plumbed from each of the four column outlets through the incubator chamber side portal for air sampling (Figure 3). An adsorbent cartridge containing 400 mg/200 mg Anasorb CSC, coconut charcoal (prepared by SKC West, Fullerton) was attached to the tubing and air collected through the soil column and charcoal at a nominal flow rate of 300 ml/min using SKC air sampling collection units (SKC Model 224-PCXR3).

11 Food and Environmental Quality Laboratory Page 11 of 90 Figure 3: Incubation temperature control, air sampling units, and soil column apparatus The sandy loam soil used in all evaluations (sand 85%; silt 11%; clay; 4% with 0.7% organic matter) was collected from a non-fumigated section of a center-pivot circle which has been in potato production during the growing season in Franklin County WA. The soil was prepared by air-drying then sieving though 2 mm. To negate the possible influence of microbial degradation, the sieved soil was sterilized by autoclaving individual 4 kg batches for two 1-hours intervals at 120 C according to procedures outlined in Zheng et al (Zheng W, S.R. Yates, Papiernik S.K., Nunez J. 2006) Conversion of metam sodium and emission of fumigant from soil columns. Atmos. Environ ). The sterilization procedure is also described in APPENDIX A: Project Protocol. Each batch of sterilized soil was packaged in plastic sampling bags, assigned a lot number and stored before use. To prepare each soil column, 4-kg of sieved, sterilized soil was brought to ca. 80% field moisture capacity by adding 400 ml deionized water and homogenizing. The soil was then packed into one of the four test columns (A, B, C, D). This water addition together with the 100 ml water for dosing the chambers brought the soil moisture to 12.5% (w/w), similar to label requirements for field applications of metam sodium. ii. Incubation After the initial 400 ml DI water addition, the four soil columns were placed in a Percival incubation system (Figure 3) equilibrated ca. 12 hours before the fumigant application. Incubation evaluations were conducted at approximately 35, 40, 45, 55, 70 and 90 degree Fahrenheit. Table 1, Section II, Sample History, lists the average actual temperature of the soil column experiments over the ca. 48 hour experimental timeframe. Temperatures were monitored at five minute intervals throughout each incremental temperature experiment by a Hobo U data logger with K-type thermocouples attached to Column A. Two Hobo devices were used; one to monitor the flow-through headspace air temperature while the second probe monitored mid-column soil temperature. Figures 4-9 provide the temperature profiles for each incubation.

12 Food and Environmental Quality Laboratory Page 12 of 90 Prior to fumigant application, soil columns were attached to SKC-PCX3 air sampling units modified to continuously collect 300 ml/min air flow over the soil column headspace. Each of the four air sampling units were calibrated before use. MITC in the head space air was captured on a 600-mg activated charcoal cartridge placed in line between the outlet of each column and the SKC air sampling unit. A pre-application air sample was taken from each soil column to establish background MITC air concentrations (if any). iii. Fumigant Application A dosing solution equivalent to 75 GPA metam sodium was applied to the replicate A, B and C soil columns for each incremental temperature evaluation. The application solution was prepared individually for each soil column by adding 1.2 ml Sectagon 42 to 100 ml deionized water. Immediately after dosing, the 600 mg activated charcoal sample cartridges were placed in line with the column outlets of chambers A,B,C, and the control soil chamber D to collect MITC emissions. One hundred ml DI water was added to the D column at the time of application to uniformly simulate soil moisture conditions. iv. Column Headspace Sampling Column air sampling was conducted continuously pre-application and for a minimum of 48 hours after fumigant application. Sampling intervals were conducted at 120 minute periods for the 35 F, 40 F, 45 F, 55 F, and 70 F incremental soil temperature evaluations. To minimize the potential affect of moisture on adsorbent deactivation, sampling was intensified to 60 minute periods over a 48-hour experimental time frame for the 90 F evaluation. Immediately after air sampling, charcoal cartridges were capped and placed in frozen storage for subsequent analysis. The start time, end time, and flow rate for each air sample was logged on laboratory data sheets for the project. All collected raw laboratory data will be retained with the project files at FEQL. In addition to the continuous air sampling of each treated and control column, spiked fortification samples were periodically tested on the D control soil column at each incremental temperature. These quality control fortifications were prepared by injecting a known amount MITC reference solution into the D activated charcoal cartridge prior to air sampling. Air was sampled through the cartridge at a rate of ca. 300 ml/min for the sampling interval. These cartridge fortified samples were prepared to demonstrate the integrity of capturing MITC under actual laboratory test conditions for each incremental temperature series.

13 Food and Environmental Quality Laboratory Page 13 of 90 B. Modifications to the Protocol The following modifications to the study protocol were employed for this study: The protocol calls for soil column incubation evaluations at 35 F, 40 F, 50 F, 60 F, 70 F, 80 F, 90 F. Soil temperature averaged over the hour incremental temperature time frames were at ca. 36, 37, 45, 54, 68, and 90 F. For the 35 F evaluation, the air flow rate was measured at the soil column inlet according to the protocol. This procedure destabilized the temperature of the controlled system while to door was opened. As a result, for each subsequent evaluation the flow rate was measured at the inlet to the charcoal cartridge. This modification allowed the flow rate to be measured regularly without affecting the temperature conditions of the systems inside the incubator (see Figure 4). The flow rate at the inlet of the soil column, however, was verified at the beginning, mid operation, and at the end of each incremental temperature evaluation. Due to excessive air restriction and increased flow variability, a charcoal air filtering cartridge was not employed on the inlet side of the soil column. The concurrently ran control soil column for each incremental temperature series was used to confirm that the air inside the system was not contaminated. Due to higher moisture collected on the activated charcoal cartridges during the 90 F soil column evaluation, the samples were stored at -20 C and were extracted/analyzed soon after sampling (see APPENDIX B: Sample Inventory & History). The GC method provided in the protocol was modified with a slightly longer hold time on the oven program (3 min) to ensure complete elution of the MITC peak on both instruments used for analysis. C. Working Analytical Method In 2005, FEQL developed and validated a working analytical method for the determination of methyl isothiocyanate (MITC) from charcoal sampling tubes (FEQL-NG-0605). This method was adapted from the California Department of Pesticide Regulation Air Monitoring for Methylisothiocyanate During a Sprinkler Application of Metam-Sodium Report EH 94-02, The procedure involves extraction of the charcoal media using a 20% mixture of carbon disulfide in 80% ethyl acetate followed by sonication and filtration through a 0.45 μm Teflon membrane. For previous method validation and recovery information, refer to the following projects: FEQL-NG-0605, MITC residential community air assessment; south Franklin County, WA; FEQL-1106 Optimizing fumigant efficacy while minimizing off-target volatile emissions; FEQL-0208 Methyl isothiocyanate air sampling breakthrough evaluations; FEQL-1207A MITC residential community air assessment; Franklin County, WA FEQL-1207B Near field emissions of MITC following shank injection and chemigation metam applications; FEQL-0708 Quantification of MITC in activated charcoal air cartridges from two chemigated circles in Eastern Washington State. FEQL MITC Residential Community Air Assessment; Franklin County, Washington

14 Food and Environmental Quality Laboratory Page 14 of 90 In brief, the charcoal is removed from the glass cartridge and transferred into 25 ml Corex tubes. A volumetric amount of the extraction solvent (5 ml of 20% carbon disulfide, 80% ethyl acetate) and ca. 2 g of sodium sulfate are added to each sample. The samples are then sonicated for approximately 2 minutes then vortexed. Sample extracts are filtered using Whatman 0.45 µm PTFE syringe filter, diluted as necessary, and placed in 2 ml auto sampler vials for analysis by gas chromatography with nitrogen phosphorus detection (GC/NPD). The working method for this study is provided as part of the FEQL protocol, Appendix A. The method was modified to account for anticipated greater water vapor moisture on charcoal at the higher incremental column temperatures by adding anhydrous sodium sulfate during solvent extraction. The working method was validated specifically for the 600 mg activated charcoal cartridges used for all incremental temperature assessments. D. Quantification i. Instrumentation Two Varian Star 3400CX gas chromatographs with nitrogen-phosphorus specific detection (NPD) and 8200CX autosamplers were used for MITC detection and quantification (instrument IDs: Moe and Curly). Operating conditions are specified below. Column: Alltech EC-WAX, 15m x 0.53mm, 1.20 μm film thickness Carrier gas: Ultrapure helium, 3-5 ml/min at 55 C. Temperatures: Detector: 260 C Injector port: 55 C to 225 C (rate: 225 o C/min), hold 5 min. Oven program: Initial: 55 C, hold for 0.09min. Ramp 10 C/min to 90 C, hold for 3 min. Retention time: MITC retention time is based on the observed retention times of external calibration standards in each set and is dependent upon instrument used. Detector: NPD bead current 3.2 A (Moe), A (Curly) Detector gases: Typical NPD detector gas flow rates were set at approximately 3-4 ml/min hydrogen, 170 ml/min air, and ml/min nitrogen makeup. Injection volume: 1 μl Integration of chromatographic data was performed using Varian Star Chromatography Workstation software. Representative chromatograms are provided in Appendix C.

15 Food and Environmental Quality Laboratory Page 15 of 90 ii. Calculations The quantification of MITC residues in the charcoal air sample cartridges was performed by electronic peak area measurement and comparison to the linear regression from a minimum of four external standards in the concentration range µg/ml. Samples were diluted as needed to quantify results within the standards range. To assure high quality during GC operation, all samples were bracketed with external calibration standards during the analytical set. Linearity and calibration standards were then used to construct the calibration curve using a spreadsheet program (Microsoft Excel ). Total MITC residue of each cartridge is calculated according to equation 1. Eq 1: Total Residue (µg) = (x µg/ml detected concentration) (Final volume of extract) For example, sample set , dated 5/29/2010 included the preparation of air sample 55-20/22-B. The sample was extracted in 5 ml and diluted 1/10 for analysis, for an equivalent final volume of 50 ml. The MITC linear regression line of best fit calculated from calibration standards 10 to 150 ug/ml (R 2 = 0.998) of this set was: Y (peak area)= m(slope) X(detected concentration in ug/ml) + b(intercept) Y = X The MITC-peak area count for this residue sample was Therefore, the concentration (in µg/ml) was: = X X = ( ) = µg/ml The total MITC concentration is then calculated according to Eq. 1: µg/ml x 50 ml = µg MITC Once the total micrograms per sample was obtained, the concentration per cubic meter air was calculated by equation 2. Eq 2: μg/m 3 = (x μg total MITC per sample)/ (total m 3 of air sampled) From the example above, air was sampled at 300 ml/min for 120 minutes, or m 3 of air: μg/m 3 = μg MITC / m 3 = 1.29 x 10 5 μg/m 3 MITC Each sample air concentration represents the amount of MITC collected over the specific time interval of the sample. Cartridge sampling times and flow rates, were recorded on

16 Food and Environmental Quality Laboratory Page 16 of 90 the laboratory data sheets. Recorded flow rates per interval were used to calculate the total amount of air sampled for each individual cartridge. Moreover, an emission flux was calculated for each sample. Flux was calculated as a measure of total μg MITC per surface area per second. Sample 55-20/22-B was sampled for 120 minutes from Column B, with a surface area of m 2. Therefore the flux term for this sample is: 55-20/22-B Flux = ( µg MITC)/( m 2 )/(120 min*60 sec/min) 55-20/22-B Flux = 38.1 µg m -2 sec -1 To assess overall analysis precision and percent recovery, control cartridges were fortified with a known amount of MITC prior to extraction. For each analytical set, recovery for the fortified sample was calculated using peak areas according to equation 4. Eq.4: % Recovery = (Fortified Peak Control Peak)Calculated Residue Fortification Amount x 100 For example, a control cartridge included in set (0809-FS53), was fortified with 125 μg of MITC. The sample extract was prepared to a final volume of 5 ml for residue determination. The MITC peak area count for this fortified sample was The peak area count for its corresponding control at the same dilution was 490 area counts. The fortified sample concentration from the linear regression for this set is then: ( ) = X X= µg/ml The total residue is then calculated according to Eq. 1: μg /ml x 5 ml = μg MITC From Eq. 4, the percent recovery for this fortified sample was: E. Method Validation and Analytical Limits Percent Recovery = μg x 100 = 102% 125 μg The working analytical method was validated prior to the analysis of any samples by fortifying and recovering MITC from 600 mg cartridges. The method was validated in triplicate at 100 and 250 µg MITC. For this study, the method limit of quantitation (LOQ) is defined by the low end of the linearity standards, 10 µg/ml, or 50 µg MITC in the 5 ml extract final volume.

17 Food and Environmental Quality Laboratory Page 17 of 90 In addition to method validation, fortified matrix samples were extracted concurrently with study samples. Concurrent fortifications performed with analytical sets ranged from 100 to 2,500 µg MITC to demonstrate the ruggedness of the method at varying air concentration levels of MITC. Table 2, Section V. Results, lists the project recoveries of validation and concurrent fortified samples. MITC air concentrations were not corrected for percent recoveries of concurrent fortified laboratory and/or soil column fortifications. F. Interferences There were no interferences in the chromatographic window of retention time for MITC. G. Confirmatory Techniques External analytical standards were used to confirm the presence of MITC residues by retention time. H. Time Required For Evaluation The time required for soil preparation was a minimum 12 hours air-drying time, ca. 2 hours to sieve four 4-kg soil column aliquots, and ca. 2 days for autoclaving the soil. Soil moisture adjustment and homogenizing took ca. 2 hours per each incremental temperature evaluation. Controlled temperature system evaluations for each incremental temperature experiment from pre-application sampling to completion required a minimum of 50 hours. The time required for an experienced person to work up a set of samples (approximately 12 samples plus 1 control, and 1 fortified sample) for analysis was approximately 2 hours. The time required for the GC analysis of a single sample was approximately 9 minutes. The duration of the analysis of a sample set depended upon the number of samples in a set and was automated using the auto sampler associated with the instrument. V. Results and Discussion The flow-through soil column design was found to be rugged for effectively quantifying MITC emissions from the column head space at all incremental temperatures. The controlled incubation system for the incremental soil temperature evaluations was stable but some variability existed during the dosing phase, particularly at the colder temperatures. For the 35 F evaluation, the air flow rate was measured at the soil column inlet according to the protocol. This procedure shortly destabilized the temperature of the controlled system (see Figure 4). As a result, for each subsequent evaluation the flow rate was measured at the inlet to the charcoal cartridge. This modification allowed the flow rate to be measured regularly without affecting the temperature conditions of the columns inside the incubator Concurrent laboratory fortifications performed with each analytical set on 600 mg activated charcoal cartridges ranged from 100 to 2,500 µg total MITC. The method limit of quantitation was defined at 50 µg (i.e., 10 µg/ml in 5 ml total volume). In fact, the method is much more sensitive than stated for this study; however, lower sensitivity was not required for these samples. The method validation and fortification recovery results are summarized in Table 2. The average

18 Food and Environmental Quality Laboratory Page 18 of 90 MITC recovery from laboratory fortifications performed with each analytical sample set was 97 ± 9.2% (n=63). The overall average recovery from activated charcoal fortified with a known amount of MITC and concurrently sampled through the D-soil column outlet for all incremental temperature series was 99 ± 15% (n= 35). Table 3 provides the percent recoveries for the soil column fortifications performed throughout the study. There was good agreement in reproducibility in MITC air concentrations among replicate A, B, and C soil columns. Some variability was evident in the 70 o F was observed with the B soil column consistently producing higher MITC air concentrations throughout the study timeframe. In all, the quality control among laboratory and soil column fortifications (and control background samples) consistently demonstrated exceptional reliability of the soil chamber system and analytical method for air concentration values over the full range of incremental temperatures. One 90 o F soil column fortification sample showed high recoveries outside of the acceptable range. For this interval, cross-contamination was evident in concurrent recovery and soil column fortified MITC samples which were ca.10 times lower in concentration than the air samples taken at this period. Figure 1 graphically illustrates the effect of incremental temperature rise on MITC flux emission. Individual MITC air concentration results from the incremental temperature evaluations are presented in Tables 4-9. Individual results are graphically illustrated in the accompanying figures. The collected data shows conversion time of MS to MITC, product soil retention, and subsequent MITC air emissions are highly dependent on soil temperature with this agricultural soil at product label application conditions. Maximum MITC air concentrations were observed to occur within the 1-2 hour interval sampling period for the 90 o F series whereas maximum MITC conversion occurred over a 4-8 hour sampling period for the cooler soil column temperatures examined. This rapid abiotic conversion under laboratory conditions was anticipated based on our experiences and previous reported studies of metam sodium in soil (Smelt and Leistra, 1974). Preliminary soil column experiments by Zheng (2006) conducted at laboratory room temperature also showed that the transformation of MS to MITC completes within 0.5 hours. The loss of measured MITC surface emissions after conversion of MS to MITC approximated first order behavior at all observed temperatures (r ). MITC half-lives estimated after maximum MS conversion for each incremental temperature experiment ranged over seven-fold from 2.5 hours at 90 o F to ca. 18 hours at the cooler soil column temperatures. Figure 2 presents total MITC released over time for each incremental temperature during the 2- day period. Cumulative emission losses are expressed as a percentage of total applied fumigant (assuming 100% conversion of MS to MITC). The cumulative loss of the total applied was observed to be associated with temperature where, after 12 hours, 20% of the soil-applied MITC was released to the air at ca. 35 o F while ca. 50% was lost from the soil column at ca. 90 o F. It is assumed that the percent of the total applied not accounted in the air was retained within the treated soil. There have been few studies in the peer-reviewed literature that have comprehensively assessed the temperature dependence of MITC loss from soil after MS application. Ma et al. (2001) provided temperature comparisons of MITC degradation from 20 o C (68 o F) through 40 o C (104 o F) in sterilized and non-sterilized soils and suggested that microbial degradation was a major dissipation pathway. This current study demonstrates that soil temperature during and shortly after application is a principle abiotic factor controlling fumigant retention in soil and rates of airborne MITC field emissions. All raw data (in Excel format) used in the construction of this analytical summary report can be found at

19 Food and Environmental Quality Laboratory Page 19 of 90 Table 2 MITC Method Validation and Concurrent Fortification Recovery Results Soil Column Fortification Sample ID 600 mg cartridge Fortification (µg) Recovery Range (%) Average Recovery (%) ± 8 (n=4) ± 12 (n=10) ± 8 (n=17) ± 5 (n=15) ± 11 (n=6) ± 11 (n=11) Table 3 Soil Column Fortification Results Air Sample Duration (min) Fortification (µg) Recovery (µg) Recovery (%) 35-8/10-D-FS % 35-16/18-D-FS % 35-24/26-D-FS % 35-32/34-D-FS % 35-40/42-D-FS % 35-48/52-D-FS % 40-8/10-D-FS % 40-16/18-D-FS % 40-24/26-D-FS % 40-32/34-D-FS % 40-42/44-D-FS % 45-8/10-D-FS % 45-16/18-D-FS % 45-26/28-D-FS % 45-34/36-D-FS % 45-42/44-D-FS % 55-6/8-D-FS % 55-14/16/D-FS % 55-22/24-D-FS % 55-34/36-D-FS % 55-44/46-D-FS %

20 Food and Environmental Quality Laboratory Page 20 of 90 Soil Column Fortification Sample ID Air Sample Duration (min) Fortification (µg) Recovery (µg) Recovery (%) 70-6/8-D-FS % 70-14/16-D-FS % 70-22/24-D-FS % 70-30/32-D-FS % 70-40/42-D-FS % 90-1/2-D-FS % /4-D-FS % 90-5/6-D-FS % 90-9/10-D-FS % 90-13/14-D-FS % 90-17/18-D-FS % 90-25/26-D-FS % 90-32/33-D-FS % 90-39/40-D-FS % 90-47/48-D-FS % Average Recovery = 99% (n=35) Standard Deviation = 15% 1- This set had exceptionally high residues, cross contamination evident in concurrent recovery and soil column fortified samples which were ~10x lower concentration than residue samples.

21 Food and Environmental Quality Laboratory Page 21 of 90 Table 4: 35 o F Evaluation (Averaged Soil Column Temp =36 o F) Sample Sample ID Duration (min) Total MITC (ug) 35-(-2/0)-A 120 <LOQ MITC (ug/m3) Flux (ug/m2/sec) 35-0/2-A E /4-A E /6-A E /8-A E /10-A E /12-A E /14-A E /16-A E /18-A E /20-A E /22-A E /24-A E /26-A E /28-A E /30-A E /32-A E /34-A E /36-A E /38-A E /40-A E /42-A E /44-A E /46-A E /48-A E /52-A E (-2/0)-B 120 <LOQ 35-0/2-B E /4-B E /6-B E /8-B E /10-B E /12-B E /14-B E /16-B E

22 Food and Environmental Quality Laboratory Page 22 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 35-16/18-B E /20-B E /22-B E /24-B E /26-B E /28-B E /30-B E /32-B E /34-B E /36-B E /38-B E /40-B E /42-B E /44-B E /46-B E /48-B E /52-B E (-2/0)-C 120 <LOQ 35-0/2-C E /4-C E /6-C E /8-C E /10-C E /12-C E /14-C E /16-C E /18-C E /20-C E /22-C E /24-C E /26-C E /28-C E /30-C E /32-C E /34-C E /36-C E

23 Food and Environmental Quality Laboratory Page 23 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 35-36/38-C E /40-C E /42-C E /44-C E /46-C E /48-C E /52-C E (-2/0)-D <LOQ 35-0/2-D 120 <LOQ 35-2/4-D 120 <LOQ 35-4/6-D 120 <LOQ 35-6/8-D 120 <LOQ 35-8/10-D-FS % NA 35-10/12-D 120 <LOQ 35-12/14-D 120 <LOQ 35-14/16-D 120 <LOQ 35-16/18-D-FS % 35-18/20-D 120 <LOQ 35-20/22-D 120 <LOQ 35-22/24-D 120 <LOQ 35-24/26-D-FS % NA 35-26/28-D 120 <LOQ 35-28/30-D 120 <LOQ 35-30/32-D 120 <LOQ 35-32/34-D-FS % NA 35-34/36-D 120 <LOQ 35-36/38-D 120 <LOQ 35-38/40-D 120 <LOQ 35-40/42-D-FS % 35-42/44-D 120 <LOQ 35-44/46-D 120 <LOQ 35-46/48-D 120 <LOQ 35-48/52-D-FS % 1 D control soil column were analyzed periodically to evaluate background MITC levels 2 D control soil column cartridges were periodically fortified (FS) with a known amount of MITC to confirm percent recovery and test for breakthrough

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25 Food and Environmental Quality Laboratory Page 25 of 90 Table 5: 40 o F Evaluation (Averaged Soil Column Temp 37 o F) Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 40-(-2/0)-A 120 <LOQ 40-0/2-A E /4-A E /6-A E /8-A E /10-A E /12-A E /14-A E /16-A 0 <LOQ 40-16/18-A E /20-A E /22-A E /24-A E /26-A E /28-A E /30-A E /32-A E /34-A E /36-A E /38-A E /40-A E /42-A E /44-A E /46-A E /48-A E /52-A E /56-A E /60-A E (-2/0)-B 120 <LOQ 40-0/2-B E /4-B E /6-B E /8-B E /10-B E /12-B E

26 Food and Environmental Quality Laboratory Page 26 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 40-12/14-B E /16-B E /18-B E /20-B E /22-B E /24-B E /26-B E /28-B E /30-B E /32-B E /34-B E /36-B E /38-B E /40-B E /42-B E /44-B E /46-B E /48-B E /52-B E /56-B E /60-B E (-2/0)-C 120 <LOQ 40-0/2-C E /4-C E /6-C E /8-C E /10-C E /12-C E /14-C E /16-C E /18-C E /20-C E /22-C E /24-C E /26-C E /28-C E

27 Food and Environmental Quality Laboratory Page 27 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 40-28/30-C E /32-C E /34-C E /36-C E /38-C E /40-C E /42-C E /44-C E /46-C E /48-C E /52-C E /56-C E /60-C E (-2/0)-D <LOQ 40-0/2-D 120 <LOQ 40-2/4-D 120 <LOQ 40-4/6-D 120 <LOQ 40-6/8-D 120 <LOQ 40-8/10-D-FS % 40-10/12-D 120 <LOQ 40-12/14-D 120 <LOQ 40-14/16-D 120 <LOQ 40-16/18-D-FS % 40-18/20-D /22-D 120 <LOQ 40-22/24-D 120 <LOQ 40-24/26-D-FS % 40-26/28-D 120 <LOQ 40-28/30-D 120 <LOQ 40-30/32-D 120 <LOQ 40-32/34-D-FS % 40-34/36-D 120 <LOQ 40-36/38-D /40-D 120 sample lost 40-40/42-D 120 <LOQ 40-42/44-D-FS %

28 Food and Environmental Quality Laboratory Page 28 of 90 Sample Sample ID Duration (min) Total MITC (ug) 40-44/46-D 120 <LOQ MITC (ug/m3) Flux (ug/m2/sec) 40-46/48-D 120 <LOQ 40-48/52-D 240 <LOQ 40-52/56-D /60-D 240 <LOQ 1 D control soil column were analyzed periodically to evaluate background MITC levels 2 D control soil column cartridges were periodically fortified (FS) with a known amount of MITC to confirm percent recovery and test for breakthrough

29 Food and Environmental Quality Laboratory Page 29 of 90 Table 6: 45 o F Evaluation (Averaged Soil Column Temp 45 o F) Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 45-(-2/0)-A 120 <LOQ 45-0/2-A E /4-A E /6-A E /8-A E /10-A E /12-A E /14-A E /16-A E /18-A E /20-A E /22-A E /24-A E /26-A E /28-A E /30-A E /32-A E /34-A E /36-A E /38-A E /40-A E /42-A E /44-A E /46-A E /48-A E /52-A E (-2/0)-B 120 <LOQ 45-0/2-B E /4-B E /6-B E /8-B E /10-B E /12-B E /14-B E /16-B E

30 Food and Environmental Quality Laboratory Page 30 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 45-16/18-B E /20-B E /22-B E /24-B E /26-B E /28-B E /30-B E /32-B E /34-B E /36-B E /38-B E /40-B /42-B E /44-B E /46-B E /48-B E /52-B E (-2/0)-C 120 sample lost 45-0/2-C E /4-C E /6-C E /8-C E /10-C E /12-C E /14-C E /16-C E /18-C E /20-C E /22-C E /24-C E /26-C E /28-C E /30-C E /32-C E /34-C E /36-C E

31 Food and Environmental Quality Laboratory Page 31 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 45-36/38-C E /40-C E /42-C E /44-C E /46-C E /48-C E /52-C E (-2/0)-D <LOQ 45-0/2-D 120 <LOQ 45-2/4-D 120 <LOQ 45-4/6-D 120 <LOQ 45-6/8-D 120 <LOQ 45-8/10-D-FS % 45-10/12-D 120 <LOQ 45-12/14-D 120 <LOQ 45-14/16-D 120 <LOQ 45-16/18-D-FS % 45-18/20-D 120 lost sample 45-20/22-D 120 <LOQ 45-22/24-D 120 <LOQ 45-24/26-D 120 <LOQ 45-26/28-D-FS % 45-28/30-D 120 <LOQ 45-30/32-D 120 <LOQ 45-32/34-D 120 <LOQ 45-34/36-D-FS % 45-36/38-D 120 <LOQ 45-38/40-D 120 <LOQ 45-40/42-D 120 <LOQ 45-42/44-D-FS % 45-44/46-D 120 <LOQ 45-46/48-D 120 <LOQ 45-48/52-D 240 <LOQ 1 D control soil column were analyzed periodically to evaluate background MITC levels 2 D control soil column cartridges were periodically fortified (FS) with a known amount of MITC to confirm percent recovery and test for breakthrough

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33 Food and Environmental Quality Laboratory Page 33 of 90 Table 7: 55 o F Evaluation (Averaged Soil Column Temp 54 o F) Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 55-(-2/0)-A 120 <LOQ 55-0/2-A /4-A E /6-A E /8-A E /10-A E /12-A E /14-A E /16-A E /18-A E /20-A E /22-A E /24-A E /26-A E /28-A E /30-A E /32-A E /34-A E /36-A E /38-A E /40-A E /42-A E /44-A E /46-A E /48-A E (-2/0)-B 120 <LOQ 55-0/2-B E /4-B E /6-B E /8-B E /10-B E /12-B E /14-B E /16-B E /18-B E

34 Food and Environmental Quality Laboratory Page 34 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 55-18/20-B E /22-B E /24-B E /26-B E /28-B E /30-B E /32-B E /34-B E /36-B E /38-B E /40-B E /42-B E /44-B E /46-B E /48-B E (-2/0)-C 120 <LOQ 55-0/2-C E /4-C E /6-C E /8-C E /10-C E /12-C E /14-C E /16-C E /18-C E /20-C E /22-C E /24-C E /26-C E /28-C E /30-C E /32-C E /34-C E /36-C E /38-C E /40-C E

35 Food and Environmental Quality Laboratory Page 35 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 55-40/42-C E /44-C E /46-C E /48-C E (-2/0)-D <LOQ 55-0/2-D 120 <LOQ 55-2/4-D 120 <LOQ 55-4/6-D 120 <LOQ 55-6/8-D-FS % 55-8/10-D 120 <LOQ 55-10/12-D 120 <LOQ 55-12/14-D 120 <LOQ 55-14/16/D-FS % 55-16/18-D 120 <LOQ 55-18/20-D 55-20/22-D 55-22/24-D-FS % 55-24/26-D 55-26/28-D 120 <LOQ 55-28/30-D 120 <LOQ 55-30/32-D 120 <LOQ 55-32/34-D 120 <LOQ 55-34/36-D-FS % 55-36/38-D 120 <LOQ 55-38/40-D 55-40/42-D 120 <LOQ 55-42/44-D 120 <LOQ 55-44/46-D-FS % 55-46/48-D 1 D control soil column were analyzed periodically to evaluate background MITC levels 2 D control soil column cartridges were periodically fortified (FS) with a known amount of MITC to confirm percent recovery and test for breakthrough

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37 Food and Environmental Quality Laboratory Page 37 of 90 Table 8: 70 o F Evaluation (Averaged Soil Column Temp 68 o F) Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 70-(-2/0)-A 120 <LOQ 70-0/2-A E /4-A E /6-A E /8-A E /10-A E /12-A E /14-A E /16-A E /18-A E /20-A E /22-A E /24-A E /26-A E /28-A E /30-A E /32-A E /34-A E /36-A E /38-A E /40-A E /42-A E /44-A E /46-A E /48-A E (-2/0)-B 120 <LOQ 70-0/2-B E /4-B E /6-B E /8-B E /10-B E /12-B E /14-B E /16-B E /18-B E

38 Food and Environmental Quality Laboratory Page 38 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 70-18/20-B E /22-B E /24-B E /26-B E /28-B E /30-B E /32-B E /34-B E /36-B E /38-B E /40-B E /42-B E /44-B E /46-B E /48-B E (-2/0)-C 120 <LOQ 70-0/2-C E /4-C E /6-C E /8-C E /10-C E /12-C E /14-C E /16-C E /18-C E /20-C E /22-C E /24-B E /26-C E /28-C E /30-C E /32-C E /34-C E /36-C E /38-C E /40-C E

39 Food and Environmental Quality Laboratory Page 39 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 70-40/42-C E /44-C E /46-C E /48-C E (-2/0)-D 120 <LOQ 70-0/2-D /4-D 70-4/6-D 70-6/8-D-FS % 70-8/10-D 70-10/12-D 70-12/14-D 70-14/16-D-FS % 70-16/18-D 120 <LOQ 70-18/20-D 120 <LOQ 70-20/22-D 120 <LOQ 70-22/24-D-FS % 70-24/26-D 70-26/28-D 70-28/30-D 70-30/32-D-FS % 70-32/34-D 120 <LOQ 70-34/36-D 120 <LOQ 70-36/38-D 120 <LOQ 70-38/40-D 120 <LOQ 70-40/42-D-FS % 70-42/44-D 120 <LOQ 70-44/46-D 120 <LOQ 70-46/48-D 120 <LOQ 1 D control soil column were analyzed periodically to evaluate background MITC levels 2 D control soil column cartridges were periodically fortified (FS) with a known amount of MITC to confirm percent recovery and test for breakthrough

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41 Food and Environmental Quality Laboratory Page 41 of 90 Table 9: 90 o F Evaluation (Average Soil Column Temp 90 o F) Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 90-(-2/-1)-A 60 <LOQ 90-0/1-A E /2-A E /3-A E /4-A E /5-A E /6-A E /7-A E /8-A E /9-A E /10-A E /11-A E /12-A E /13-A E /14-A E /15-A E /16-A E /17-A E /18-A E /19-A E /20-A E /21-A E /22-A E /23-A E /24-A E /25-A E /26-A E )27-A E /28-A E /29-A E /30-A E /31-A E /32-A E /33-A E /34-A E /35-A E

42 Food and Environmental Quality Laboratory Page 42 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 90-35/36-A E /37-A E /38-A E /39-A E /40-A E /41-A E /42-A E /43-A E /44-A E /45-A E /46-A E /47-A E /48-A E (-2/-1)-B 60 <LOQ 90-0/1-B E /2-B E /3-B E /4-B E /5-B E /6-B E /7-B E /8-B E /9-B /10-B E /11-B E /12-B E /13-B E /14-B E /15-B E /16-B E /17-B E /18-B E /19-B E /20-B E /21-B E /22-B E

43 Food and Environmental Quality Laboratory Page 43 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 90-22/23-B E /24-B E /25-B E /26-B E )27-B E /28-B E /29-B E /30-B E /31-B E /32-B E /33-B E /34-B E /35-B E /36-B E /37-B E /38-B E /39-B E /40-B E /41-B E /42-B 60 <LOQ 90-42/43-B 60 <LOQ 90-43/44-B 60 <LOQ 90-44/45-B 60 <LOQ 90-45/46-B 60 <LOQ 90-46/47-B 60 <LOQ 90-47/48-B 60 <LOQ 90-(-2/-1)-C 60 <LOQ 90-0/1-C E /2-C E /3-C E /4-C E /5-C E /6-C E /7-C E /8-C E /9-C E

44 Food and Environmental Quality Laboratory Page 44 of 90 Sample ID Sample Duration (min) Total MITC (ug) MITC (ug/m3) Flux (ug/m2/sec) 90-9/10-C E /11-C E /12-C E /13-C E /14-C E /15-C E /16-C E /17-C E /18-C E /19-C E /20-C E /21-C E /22-C E /23-C E /24-C E /25-C E /26-C E )27-C E /28-C E /29-C E /30-C E /31-C E /32-C E /33-C E /34-C E /35-C E /36-C E /37-C E /38-C E /39-C E /40-C E /41-C E /42-C E /43-C E /44-C E /45-C E /46-C E

45 Food and Environmental Quality Laboratory Page 45 of 90 Sample Sample ID Duration (min) Total MITC (ug) 90-46/47-C 60 <LOQ 90-47/48-C 60 <LOQ MITC (ug/m3) Flux (ug/m2/sec) 90-(-2/-1)-D 1 60 <LOQ 90-0/1-D 60 <LOQ 90-1/2-D-FS % 90-3/4-D-FS % 90-4/5-D 60 <LOQ 90-5/6-D-FS % 90-6/7-D 90-7/8-D 60 <LOQ 90-8/9-D 60 <LOQ 90-9/10-D-FS % 90-10/11-D 60 <LOQ 90-11/12-D 60 <LOQ 90-12/13-D 60 <LOQ 90-13/14-D-FS % 90-14/15-D 60 <LOQ 90-15/16-D 60 <LOQ 90-16/17-D 60 <LOQ 90-17/18-D-FS % 90-18/19-D 60 <LOQ D 60 <LOQ 90-20/21-D 60 <LOQ 90-21/22-D 60 <LOQ 90-22/23-D 60 <LOQ 90-23/24-D 60 <LOQ 90-24/25-D 60 <LOQ 90-25/26-D-FS % 90-26/27-D 90-27/28-D 90-28/29-D 90-29/30-D 90-30/31-D 90-31/32-D 90-32/33-D-FS % 90-33/34-D

46 Food and Environmental Quality Laboratory Page 46 of 90 Sample ID 90-34/35-D 90-35/36-D 90-36/37-D 90-37/38-D 90-38/39-D Sample Duration (min) Total MITC (ug) MITC (ug/m3) 90-39/40-D-FS % 90-40/41-D 90-41/42-D 90-42/43-D 90-43/44-D 60 <LOQ 90-44/45-D 90-45/46-D 60 <LOQ 90-46/47-D 60 <LOQ Flux (ug/m2/sec) 90-47/48-D-FS % 1 D control soil column were analyzed periodically to evaluate background MITC levels 2 D control soil column cartridges were periodically fortified (FS) with a known amount of MITC to confirm percent recovery and test for breakthrough

47 Food and Environmental Quality Laboratory Page 47 of 90 Figure 4: 35 o F Evaluation Air/Soil Temperature Profiles

48 Food and Environmental Quality Laboratory Page 48 of 90 Figure 5: 40 o F Evaluation Air/Soil Temperature Profiles

49 Food and Environmental Quality Laboratory Page 49 of 90 Figure 6: 45 o F Evaluation Air/Soil Temperature Profiles

50 Food and Environmental Quality Laboratory Page 50 of 90 Figure 7: 55 o F Evaluation Air/Soil Temperature Profiles

51 Food and Environmental Quality Laboratory Page 51 of 90 Figure 8: 70 o F Evaluation Air/Soil Temperature Profiles

52 Food and Environmental Quality Laboratory Page 52 of 90 Figure 9: 90 o F Evaluation Air/Soil Temperature Profiles

53 Food and Environmental Quality Laboratory Page 53 of 90 APPENDIX A: Project Protocol

54 Food and Environmental Quality Laboratory Page 54 of 90