Page 2 of 38 

1.0 Introduction

This document serves as the human health risk assessment for methyl bromide which is based on the 

results of the recent emission studies completed under the MBIP research plan. These studies can be 

identified by the following information: 

EPA MRID 480060-01: Monitoring of Methyl Bromide and Chloropicrin Field Emissions From 

Shank Applications at Shallow and Deep Injection Depths; Authors: Ajwa, H. and Sullivan, D,; 

Sponsor: Methyl Bromide Industry Panel, LLC c/o David McAllister Chemtura Corporation 1801 

Highway 52, West Lafayette IN 93905 

EPA MRID 481076-01: Monitoring of Methyl Bromide and Chloropicrin Field Emissions From 

Shank Applications (Bedded and Broadcast) and a Methyl Bromide Hot-Gas Application Under 

Totally Impermeable Film; Authors: Ajwa, H. and Sullivan, D,; Sponsor: Methyl Bromide Industry 

Panel and Hendrix and Dail, Inc. 

This document provides several types of information including: 

• Section 2: Study Results – The design and results of the studies are summarized as well as any 

data quality issues which have been identified are described in this section. 

• Section 3: Flux Calculations - The flux calculations completed based on the data are described. 

Values are also compared to previous emission profiles used for methyl bromide. 

• Section 4: 1st Principles Factors – The different conditions in the fields which may have an impact 

on the factors which regulate emissions are presented. 

• Section 5: Risk Analysis - Modeling outputs are summarized and discussed in this section. 

• Section 6: Conclusions - This section contains a summary of the overall conduct of the studies and 

analysis based on there results. 
Page 3 of 38 

2.0 Study Results 

 The results of the MBIP monitoring studies are summarized in this section. The data from 

California are presented in Section 2.1 while the results from the Florida site are summarized in Section 2.2.

2.1 California Study Results (MRID 480060-01) 

The design of this study featured the treatment of five 1 acre field plots located in Wasco California 

on the same day separated by a sufficient distance so the emissions from each would not interfere with one 

another. The treatment conditions examined different types of agricultural practices. All field sites were 

tarped with a “TIF” film except the control plot which was tarped with the current industry standard LDPE 

film.3 4

 In order to vary the effect of various cultural practices, different combinations of fumigation types 

(strip or broadcast), injection depths (shallow or deep), and the use of reactive adjuvants (potassium 

thiosulfate at field 3) were utilized per the research plan. All applications were made on June 2, 2009 by a 

commercial applicator using a 50/50 methyl bromide/chloropicrin product (Tri-Con 50/50 EPA Reg 11220-

10). At fields 1 through 3 a “Noble Plow” shank was used and at sites 4 and 5 forward swept chisels were 

used. Tarp cutting was completed on all fields on June 8, 2009 and removal 1 day later on June 9, 2009 

(i.e., sample period 18 is tarp cutting). The specific scenarios examined are summarized in Table 1 below. 

Table 1: Description of 5 Application Scenarios At California Site (MRID 480060-01) 

Scenario Application 

Method 

Injection 

Depth 

(inches) 

Nominal Application Rate (lb/treated acre) * Soil Sealing 

Method Product 

(Tri-Con 50/50) Methyl bromide Chloropicrin 

1 Shallow, 

broadcast tarped 12 360 180 180 Polyethylene 

tarp 

2 Shallow, 

broadcast tarped 12 360 180 180 EVOH Resin 

Barrier Tarp 

3 Shallow, 

broadcast tarped 12 360 180 180 

EVOH Resin 

Barrier Tarp & 

potassium 

thiosulfate

4 

Deep, strip, 

tarped 

(50% of field 

area treated) 

18 360 180 180 EVOH Resin 

Barrier Tarp

5 Deep, broadcast, 

tarped 18 360 180 180 EVOH Resin Barrier Tarp

*All application rates are based on the amount applied per treated area. In a broadcast application where an entire 

contiguous field is treated the entire area is accounted for in the calculation. In situations where beds or strip 

fumigation is completed only the parts of a treated field where the fumigant is actually applied are included. If desired 

this information, along with information on bed spacing can be used to calculate a broadcast equivalent rate. 

 

3 The tarp was referenced in the study report as “10.5-foot wide, 1-mil thick, EVOH-resin barrier tarp: VaporSafeTM by Raven Industries, 

Sioux Falls, SD.” A March 31, 2010 letter to J. Dawson indicating Kuraray has concerns over the description of the films used in the study. 

The letter indicated the copolymer “EVOH” can have a wide spectrum of properties based on the comonomer ratios and the specific

manufacturing process of the materials. Kuraray would have preferred the report refer to the resin as “EVALTM, more specifically EVAL 

SP292B or EVAL H171B” as these specific grades were utilized in all TIF testing conducted over the past three years. The selection of one 

grade over the other depends on the relationship between the manufacturing equipment capabilities and the desired film width, with EVAL 

SP292B providing a wider processing window than EVAL H171B. 

4 Note that current methyl bromide use permit conditions do not allow for use of high barrier films (e.g., VIF) in California commercial 

agricultural production. This study used such a film for research purposes but commercial implementation in California would depend upon a 

modification of these conditions by the California Department of Pesticide Regulation which is also reviewing these data. 
Page 4 of 38 

An overview of the research plots is presented in Figures 1, 2, and 3. Figure 1 shows each plot with 

associated GPS coordinates. Figure 2 is similar but describes the scenario associated with each plot. Figure 

3 illustrates the sampler locations around field plot 1. A similar approach was used for all plots in this 

study. All flux values were quantified in this study using the indirect method. Methyl bromide emission 

levels from each field were determined by measuring air concentrations in eight directions surrounding the 

field for six hour periods for the first two days, then every 12 hours for the remainder of the eleven days of 

monitoring, except for during the tarp splitting and removal phases in which the intervals were reverted to 

every 6 hours for this 24 hour period. Air was pumped through Anasorb 747® solid sorbent tubes to capture 

methyl bromide in the air at each sampler. Methyl bromide was extracted from the charcoal tubes with 

carbon disulfide and analyzed by gas chromatography using an electron capture detector. Appropriate 

weather data were collected and sonic anemometers were used at each plot. 

Figure1: Satellite Image of California Plots with GPS Coordinates (MRID 480060-01) 

Figure 2: Aerial Photograph of California Plots with Scenario Descriptors (MRID 480060-01) 
Page 5 of 38 

Figure 3: California Field Plot 1 with Sampler Locations (MRID 480060-01) 

Background samples indicated that no cross-contamination occurred during the monitoring. 

Analytical recovery values were acceptable and no corrections to measured residue values were warranted. 

The average percent recovery was 106.12% with a standard deviation of 13.8%. Results for blind positive 

control samples also exceeded 100 % recovery. [Note: Three samples of this type were inadvertently left 

out of ice storage during shipment and were considered invalid by the investigators – this was verified 

during the review process so the results for these samples were not included herein.] Results for duplicate 

samples also were very close indicating that there were no significant sample collection issues. The results 

of emissions studies of this type are used as the basis for developing a flux profile that is associated with the 

application method and the conditions on/around a particular field after application. The calculation of 

these profiles for each field site in this study is described below in Section 3. 

Like previous field research on methyl bromide the majority of the cumulative emissions occurred in 

the first few sampling periods after application and no significant changes in emissions were seen as a result 

of tarp cutting. This is illustrated by total mass loss over time, as calculated by the investigators, for each 

plot (Figure 4). Total emissions from Plot #1 (shallow broadcast under polyethylene tarp) were 62.48%.5

The total mass loss of methyl bromide from Plot #2 (shallow broadcast under VaporSafeTM) was 45.5%. 

When potassium thiosulfate was applied to the soil surface during the deployment of VaporSafeTM (Plot 

#3), the mass loss of methyl bromide was reduced to 22.13%. The total mass loss of methyl bromide from 

the deep strip application under VaporSafeTM was 41.77% (Plot #4). The total mass loss from the deep 

broadcast application under VaporSafeTM was 27.11% (Plot #5). [Note: Tarp cutting occurred in sample 

period 18 and in each case where VaporSafeTM (plots 2, 3, and 5) was used for broadcast applications there 

is an inflection which can be observed in Figure 4. This is likely due to methyl bromide being retained 

under the tarp and then being released by the cutting operation. In each case there appears to be a 

substantive portion of the total mass released occurring in this timeframe.] 

 

5

 For comparative purposes, the single day emission ratio established by the California Department of Pesticide Regulation permit conditions for 

methyl bromide is 0.25 and these current data indicate about 45% dissipated on the 1st day. This phenomenon would be expected given 

anticipated variability in emissions due to the number of possible factors which can influence emissions. 
Page 6 of 38 

Figure 4: Total Mass Loss for Methyl Bromide At Calfornia Test Sites (MRID 480060-01) 

 

2.2 Florida Study Results (MRID 481076-01) 

The design of this study featured the treatment of 3 field plots (0.4 to 0.6 acres) located just north of 

Fort Pierce Florida on the same day separated by a sufficient distance so the emissions from each would not 

interfere with one another. The treatment conditions examined different types of agricultural practices. All 

field sites were tarped with a “TIF” film.6

 No control plot using typical films was incorporated as in the 

California study described above. In order to vary the effect of various cultural practices, different 

fumigation types were considered (i.e., tarped shank injection, broadcast and hot-gas). Other factors such as 

the use of reactive adjuvants (potassium thiosulfate) or different film types (i.e., metalized) were not 

evaluated in the field even though they were specified in the MBIP research plan also as described above. 

The evaluation of emissions from a hot-gas treatment were also not specifically included in the MBIP 

research plan but have been previously discussed with the Agency by other stakeholders. It is not clear why 

no further attempts were made to evaluate emissions using broadcast applications after the reported tarp 

failure for that application method at Site 3 of this study.7

All applications were made on January 15, 2010 by a commercial applicator. Application using a 

50/50 methyl bromide/chloropicrin mixture for the tarped raised bed field plot 1 was made using “extralong back swept gas knives” in conjunction with a “Kennco-style bedder.” Hole punching was not included 

 

6

Report described the films used in this study as follows “VaporSafeTM (manufactured by Raven Industries, Sioux Falls, South Dakota); also 

known as “TIF” or “Totally Impermeable Film”; which is a 5-layer EVAL-resin barrier film (EVAL is a specific product of EVOH resin 

manufactured by Kuraray Americas, Houston, Texas).” 

7

 In the T. Heinzman letter (8/6/10) it was indicated that the California data should be considered representative of other regions (i.e., Florida) 

and the argument is appropriate because field capacity was 70% in California and >100% in Florida in similar soils. It also indicated Florida 

soils tend to have higher water content than in California. A comparison was also made using chloropicrin emissions data. The Agency agrees 

that California emissions are probably the best general approximation for Florida situations if specific data are lacking but that many site 

specific issues have to be considered that were not when attempting to compare specific sites such as was done in this letter (e.g., temperature, 

compaction level, application equipment specifics, etc.). It is also not appropriate to develop a rationale using chloropicrin data because of the 

significant physical/chemical differences between the two fumigants (e.g., methyl bromide is more stable and much more volatile). 

The letter also indicates that basically 30% of growers use metalized tarps for commercial production in Florida. Metalized films were to be 

evaluated in this study but no additional explanation was provided concerning why this aspect of the research plan was deleted. Finally, the 

letter also indicates that there are viable methods for gluing TIF/VIF tarps in commercial production. No further explanation of these practices 

relative to the failure at the Florida site was discussed. 
Page 7 of 38 

in this study because for high barrier tarps it is typically done between 21 and 28 days after application 

according to the study report which the investigators noted was impractical from a field research perspective 

in this case. At field plot 2 a hot-gas application was completed. The field set-up was completed the night 

prior to the application event. Drip tape was installed at approximately 9 foot intervals across the field. The 

hot-gas kettles operated at a temperature of approximately 155 degrees F and fumigant was applied at a rate 

of about 3 lb/minute. Tarp cutting for the hot gas application site was completed on January 22, 2010 (i.e., 

sampling period 19). The specific scenarios examined in this study are summarized in Table 2 below. 

Table 2: Description of 2 Application Scenarios At Florida Site (MRID 481076-01) 

Scenario Application 

Method 

Injection 

Depth 

(inches) 

Nominal Application Rate (lb/treated acre)* Soil Sealing 

Product Methyl bromide Chloropicrin Method 

1 

Shank, bedded, 

Tarped 

(59% of field area 

treated) 

8 470 

(50/50 product) 235 235 EVOH Resin Barrier Tarp 

2 Hot-gas, 

tarped 0 435 (98/2 product) 426 9 EVOH Resin Barrier Tarp 

*All application rates are based on the amount applied per treated area. In a broadcast application where an entire 

contiguous field is treated the entire area is accounted for in the calculation. In situations where beds or strip fumigation 

is completed only the parts of a treated field where the fumigant is actually applied are included. If desired this 

information, along with information on bed spacing (59%) can be used to calculate a broadcast equivalent rate.

An overview of the research plots is presented in Figures 5, 6, and 7. Figure 5 shows a satellite map 

of each plot. Associated GPS coordinates are also available if needed. Figures 6 and 7 illustrate the sampler 

locations around each of the completed field plots. Flux values in this study were quantified using both the 

indirect (used for 1st sample collection period only for the tarped raised bed site while application still 

ongoing) and direct (Integrated Horizontal Flux approach used) sampling methods. Methyl bromide 

emission levels from each field were determined by measuring air concentrations for six hour periods for 

the first two days, then every 12 hours for the remaining monitoring periods (completed 10 days after 

application, 1/25/10). In-direct samplers (N=8) were located approximately 12.2 meters from the corners 

and sides of each plot at a height of 1.5 meters. On-field samplers were located at 4 heights from the field 

including 0.3, 0.9, 1.8, and 3.0 meters. Air was pumped through Anasorb 747® solid sorbent tubes to 

capture methyl bromide in the air at each sampler. Methyl bromide was extracted from the charcoal tubes 

with carbon disulfide and analyzed by gas chromatography using an electron capture detector. Appropriate 

weather data were collected and sonic anemometers were used at each plot. 
Page 8 of 38 

Figure 5: Satellite Image of Florida Plots (MRID 481076-01) 

Figure 6: Florida Tarped Raised Bed Field Plot 1 with Sampler Locations (MRID 481076-01) 
Page 9 of 38 

Figure 7: Florida Hot-Gas Field Plot 2 with Sampler Locations (MRID 481076-01) 

Background samples indicated that no cross-contamination occurred during the monitoring. 

Analytical recovery values were acceptable and no corrections to measured residue values were made by the 

investigators (i.e., laboratory recovery = 87.5 ± 6.4% and field recovery = 86.1 ± 8.0%). However, because 

the average field recovery values were less than 90 percent residue values were corrected by the Agency for 

use in the calculation of flux estimates using the average field recovery value. Results for duplicate samples 

also were very close indicating that there were no significant sample collection issues. The results of 

emissions studies of this type are used as the basis for developing a flux profile that is associated with the 

application method and the conditions on/around a particular field after application. The calculation of 

these profiles for each field site in this study is described below in Section 3. Like previous field research 

on methyl bromide the majority of emissions occurred in the first few sampling periods after application in 

the bedded scenario with a diurnal pattern the first few days. In the hot gas treatment a diurnal pattern was 

noted following application for a day or so and a significant emissions peak was observed as a result of tarp 

cutting. 

The investigators calculated total mass loss for each plot (Figure 8). Total emissions from Plot 1 

(tarped raised bed) were 15.26 percent. The total mass loss of methyl bromide from Plot 2 (hot-gas) was 

33.4 percent. [Note: Tarp cutting occurred in sample period 19 and at the hot gas site and, as described for 

the California plots, there is an inflection which can be observed in Figure 8. This is likely due to methyl 

bromide being retained under the tarp and then being released by the cutting operation. There appears to be 

a substantive portion of the total mass released occurring in this timeframe.] 
Page 10 of 38 

0

5

10

15

20

25

30

35

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Sampling Intervals

Cumulative Mass Loss of Methyl Bromide Relative 

to Amount Applied (%)

Hot Gas (Plot 2)

Tarped Raised Bed (Plot 1)

Figure 8: Total Mass Loss for Methyl Bromide At Florida Test Sites (MRID 481076-01) 
Page 11 of 38 

3.0 Flux Calculations

 The flux estimates calculated based on the MBIP monitoring studies are summarized in this section. 

The flux estimates for the data from California are presented in Section 2.1 while the flux estimates from 

the Florida site are summarized in Section 2.2.

3.1 California Study Flux Estimates (MRID 480060-01) 

The Agency calculated flux using the indirect method and compared them against the values 

calculated by the investigators. The flux profiles were calculated based on the field conditions including the 

application rates used to make the applications in the study. For the purposes of completing the PERFUM 

analyses, these flux profiles were subsequently adjusted to an application rate for methyl bromide of 430 lb 

methyl bromide per acre treated which was the highest rate evaluated in the previous risk assessment for 

comparison purposes (Table 3). [Note: All PERFUM analyses contained an array of results based on a 

variety of application rates including the field application rate for each test plot.] Appendix A contains the 

flux rates calculated for all sampling periods at all sites. All of the values presented in Appendix A are 

based on the application rate for the particular study site and have not been adjusted to the 430 lb methyl 

bromide per treated acre rate. 

Table 3: California Site Emission Profiles Adjusted To Maximum Application Rate - Basis For PERFUM Model Analyses (MRID 480060-01) 

Application rate 

(lb MB/treated acre) 189.1 180.3 177.9 202.6 181.1 

Application start 

time 8:26 AM 8:28 AM 10:35 AM 1:18 PM (real time 18:30) 1:13 PM 

Plot 

Application method 

1 

HDPE Shallow Broad 

cast 

2 

EVOH Shallow 

Broadcast 

3 

EVOH/KTS Shallow 

Broadcast 

4 

EVOH Deep Strip 

(50% area treated) 

5 

EVOH Deep 

Broadcast 

Hour 

Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 

Flux (μg/m2-s) Flux (μg/m2-s) Flux (μg/m2-s) Flux (μg/m2-s) Flux (μg/m2-s) 

1 86.09 53.44 8.87 2.03 2.23 1.77 22.68 19.47 31.75 5.81 

2 132.68 26.02 11.50 1.04 5.44 0.94 47.45 6.34 9.01 1.01 

3 132.68 26.02 11.50 1.04 5.44 0.94 47.45 6.34 9.01 1.01 

4 132.68 26.02 11.50 1.04 5.44 0.94 47.45 6.34 9.01 1.01 

5 132.68 26.02 11.50 1.04 5.44 0.94 47.45 6.34 9.01 1.01 

6 132.68 26.02 11.50 1.04 5.44 0.94 47.45 6.34 9.01 1.01 

7 132.68 26.02 11.50 1.04 5.44 0.94 47.45 6.34 9.01 1.01 

8 63.41 32.64 5.32 36.90 5.12 17.32 10.11 11.17 2.79 8.49 

9 63.41 32.64 5.32 36.90 5.12 17.32 10.11 11.17 2.79 8.49 

10 506.97 63.41 167.53 5.32 65.47 5.12 44.37 10.11 45.79 2.79 

11 506.97 63.41 167.53 5.32 65.47 5.12 44.37 10.11 45.79 2.79 

12 506.97 63.41 167.53 5.32 65.47 5.12 44.37 10.11 45.79 2.79 

13 506.97 63.41 167.53 5.32 65.47 5.12 44.37 10.11 45.79 2.79 

14 479.64 64.05 234.24 135.43 86.14 66.43 44.37 69.18 45.79 32.02 

15 479.64 64.05 234.24 135.43 86.14 66.43 44.37 69.18 45.79 32.02 

16 479.64 64.05 234.24 135.43 86.14 66.43 44.37 69.18 45.79 32.02 

17 479.64 64.05 234.24 135.43 86.14 66.43 44.37 69.18 45.79 32.02 

18 479.64 64.05 234.24 135.43 86.14 66.43 44.37 69.18 45.79 32.02 

19 479.64 64.05 234.24 135.43 86.14 66.43 44.37 69.18 45.79 32.02 
Page 12 of 38 

Table 3: California Site Emission Profiles Adjusted To Maximum Application Rate - Basis For PERFUM Model Analyses (MRID 480060-01) 

Application rate 

(lb MB/treated acre) 189.1 180.3 177.9 202.6 181.1 

Application start 

time 8:26 AM 8:28 AM 10:35 AM 1:18 PM (real time 18:30) 1:13 PM 

Plot 

Application method 

1 

HDPE Shallow Broad 

cast 

2 

EVOH Shallow 

Broadcast 

3 

EVOH/KTS Shallow 

Broadcast 

4 

EVOH Deep Strip 

(50% area treated) 

5 

EVOH Deep 

Broadcast 

Hour 

Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 Day 1 Day 2 

Flux (μg/m2-s) Flux (μg/m2-s) Flux (μg/m2-s) Flux (μg/m2-s) Flux (μg/m2-s) 

20 86.09 53.44 8.87 2.03 2.23 1.77 22.68 19.47 31.75 5.81 

21 86.09 53.44 8.87 2.03 2.23 1.77 22.68 19.47 31.75 5.81 

22 86.09 53.44 8.87 2.03 2.23 1.77 22.68 19.47 31.75 5.81 

23 86.09 53.44 8.87 2.03 2.23 1.77 22.68 19.47 31.75 5.81 

24 86.09 53.44 8.87 2.03 2.23 1.77 22.68 19.47 31.75 5.81 

 An example of the specific analyses used to determine the flux values for each site is presented in 

Table 4 for plot 1 in this study. All analyses were completed using the indirect method. Graphs which 

illustrate the differences between the flux estimates calculated by the investigators and those calculated by 

the Agency have also been developed and an example is presented in Figure 9. In general there is good 

agreement between the values calculated by the investigators and those calculated by the Agency. The 

Agency flux profiles have been used to estimate risks using the PERFUM model. [Note: More detailed 

information can be provided if needed concerning the details of the flux calculations.] 

Table 4: Flux Calculation Details For California Field Plot 1 (MRID 480060-01) 

Period Duration 

Agency Registrant 

Estimated flux 

μg/m2-sec Source Estimated flux μg/m2-sec Source 

1 06/02/2009 09:00 - 13:00 222.95 Slope-LR 224.06 DPR Regression Slope 

2 06/02/2009 13:00 - 19:00 210.93 Slope-LR 172.81 DPR Regression Slope 

3 06/02/2009 19:00 - 01:00 37.86 Slope-LSR 64.21 Meas./Modl. Slope Fail 

4 06/03/2009 01:00 - 07:00 58.35 Slope-LSR 15.61 DPR Regression Slope 

5 06/03/2009 07:00 - 13:00 27.89 Slope-LSR 24.74 Meas./Modl. Slope Fail 

6 06/03/2009 13:00 - 19:00 28.17 Slope-LR 22.08 Meas./Modl. Slope Fail 

7 06/03/2009 19:00 - 01:00 23.50 Slope-LSR 21.43 Least Squares Slope 

8 06/04/2009 01:00 - 07:00 11.44 Slope-LSR 11.79 Least Squares Slope 

9 06/04/2009 07:00 - 19:00 14.36 Slope-LR 10.66 Meas./Modl. Slope Fail 

10 06/05/2009 19:00 - 07:00 7.24 Slope-LSR 6.62 DPR Regression Slope 

11 06/05/2009 07:00 - 19:00 5.08 Slope-LR 4.35 DPR Regression Slope 

12 06/06/2009 19:00 - 07:00 3.06 Slope-LR 2.73 DPR Regression Slope 

13 06/06/2009 07:00 - 19:00 3.68 Slope-LSR 2.89 DPR Regression Slope 

14 06/07/2009 19:00 - 07:00 1.74 Slope-LR 2.08 Least Squares Slope 

15 06/07/2009 07:00 - 19:00 3.45 Slope-LR 3.31 DPR Regression Slope 

16 06/08/2009 19:00 - 07:00 1.80 Slope-LR 2.31 Least Squares Slope 

17 06/08/2009 07:00 - 13:00 8.63 Slope-LR 6.10 Meas./Modl. Slope Fail 

18 06/08/2009 13:00 - 19:00 8.55 Slope-LSR 7.01 DPR Regression Slope 

19 06/08/2009 19:00 - 01:00 6.26 Slope-LSR 4.27 Least Squares Slope 

20 06/09/2009 01:00 - 07:00 2.62 Slope-LR 2.16 DPR Regression Slope 
Page 13 of 38 

Table 4: Flux Calculation Details For California Field Plot 1 (MRID 480060-01) 

Period Duration 

Agency Registrant 

Estimated flux 

μg/m2-sec Source Estimated flux μg/m2-sec Source 

21 06/09/2009 07:00 - 19:00 0.79 Slope-LR 0.63 DPR Regression Slope 

22 06/10/2009 19:00 - 07:00 1.25 Slope-LR 1.20 DPR Regression Slope 

23 06/10/2009 07:00 - 19:00 0.99 Slope-LSR 1.59 Meas./Modl. Slope Fail 

24 06/11/2009 19:00 - 07:00 1.05 Slope-LR 1.05 DPR Regression Slope 

25 06/11/2009 07:00 - 19:00 0.65 Slope-LSR 1.30 Below Detection Limit 

26 06/12/2009 19:00 - 07:00 0.88 Slope-LR 1.01 Least Squares Slope 

27 06/12/2009 07:00 - 19:00 0.62 Slope-LSR 1.22 Below Detection Limit 

28 06/13/2009 19:00 - 07:00 0.87 Slope-LR 0.91 DPR Regression Slope 

29 06/13/2009 07:00 - 19:00 0.52 Slope-LSR 1.30 Below Detection Limit 

30 06/14/2009 19:00 - 07:00 0.58 Slope-LR 0.56 DPR Regression Slope 

31 06/14/2009 07:00 - 19:00 0.02 Slope-LR 1.25 Below Detection Limit 

32 06/15/2009 19:00 - 07:00 0.34 Slope-LR 0.82 Least Squares Slope 

0.0

50.0

100.0

150.0

200.0

250.0

300.0

0 5 10 15 20 25 30 35

Time (Sampling Interval)

Flux (μg/m2-sec)

Agency

Registrant

Figure 9: Methyl Bromide Flux Estimates From California Field 1 (MRID 480060-01) 

Comparison of EPA and Registrant Calculated Values 

 This study was designed to elucidate the impacts of various control measures on methyl bromide 

emissions. The measures which were incorporated into this study included the use of barrier films, the use 

of a reactive adjuvant, and various types of shanks. Additionally, care was exerted to ensure that 

applications occurred that are as compliant as possible with the good agricultural practices that have been 

under development by the Agency for fumigant applications. The results indicate that the measures 

attempted in this research reduced peak emission rates compared to current typical practices and also 

impacted cumulative emissions (Figures 10 and 4, respectively). Figure 10 presents the emissions profiles 

used in the previous 2007 risk assessment to evaluate current practices (i.e., tarped, bedded tarped, and deep 

untarped) and compares them to the emissions quantified in this study for the first 24 hours after 

application. The emission profiles have all been adjusted to an application rate of 100 lb methyl 
Page 14 of 38 

bromide/treated acre to ensure a valid comparison. The profiles with the lines and dots represent the 

emission reduction options evaluated in this study. The results indicate that regardless of the other 

conditions, the barrier tarp seems to reduce emissions as does the use of the thiosulfate adjuvant. Deep 

instead of shallow injection also seems to reduce emissions. The single day cumulative emission rate 

exceeded the value currently used for this application method in the California permit conditions for methyl 

bromide (i.e., about 45% compared to 25% for shallow broadcast tarped – Permit Condition 3B1). This 

phenomenon would be expected given anticipated natural variability in emissions within similar practices 

due to the number of possible factors which can influence emissions (e.g., moisture levels, field preparation, 

tarp characteristics, etc.). This trend was also observed for the hourly flux estimates illustrated in Figure 10 

where the normalized rates for Site 1 exceed those used as the basis for the current Agency risk assessment 

because of the same issues (D337288). 

Finally, the ability of high barrier tarps to substantively retain methyl bromide over time is 

illustrated by the information presented in Appendix A. Once tarp cutting occurred after the broadcast 

applications it is clear that retained methyl bromide is released at higher levels compared to the periods just 

prior to that operation and in some cases flux is similar to values immediately after application. Thus, the 

risks associated with such a phenomena appear to be similar to or less than predicted for periods 

immediately after application. However, there are potential impacts on the duration of a buffer zone or the 

restricted entry interval for workers. 

Methyl Bromide Flux - Normalized To 100 lb/acre

0.00

25.00

50.00

75.00

100.00

125.00

150.00

175.00

200.00

Hours

Flux (ug/m2-s)

1 HDPE Shallow Broad

cast

2 EVOH Shallow

Broadcast

3 EVOH/KTS Shallow

Broadcast

4 EVOH Deep Strip

5 EVOH Deep

Broadcast

Shallow, untarped

Tarped

Bedded, Tarped

Deep, untarped

Figure 10: Comparison of MBIP Flux From California Research Plots (MRID 480060-01) and Existing Flux Estimates 

For Similar Application Methods (Normalized to 100 lb ai/acre) For 1st 24 Hours After Application 
Page 15 of 38 

3.2 Florida Study Flux Estimates (MRID 481076-01) 

The Agency calculated flux using the integrated horizontal flux method since on-field sampling was 

completed in this study and compared them against the values calculated by the investigators (except for 

Period 1 which is based on the indirect method). The flux profiles were calculated based on the field 

conditions including the application rates used to make the applications in the study. For the purposes of 

completing the PERFUM analyses, these flux profiles were subsequently adjusted to the application rate for 

methyl bromide of 430 lb methyl bromide per acre treated and for the average field recovery value for this 

site (Table 5). [Note: All PERFUM analyses contained an array of application rates including the field 

application rate for each test plot.] Appendix A contains the flux rates calculated for all sampling periods at 

all sites. All of the values presented in Appendix A are based on the application rate for the particular study 

site and have not been adjusted to the 430 lb methyl bromide per treated acre rate. 

Table 5: Florida Site Emission Profiles Adjusted To Maximum Application Rate and For Average Field Recovery – 

Basis For PERFUM Model Analyses (MRID 481076-01) 

Application rate 

(lb MB/treated acre) 235 426 

Application start 

time 09:45 AM 09:50 AM 

Plot 

Application method EVOH Raised Bed EVOH Hot Gas 

Hour 

Day 1 Day 2 Day 1 Day 2 

Flux (μg/m2-s) Flux (μg/m2-s) 

1 0.1 16.1 106.0 5.5 

2 0.1 16.1 106.0 5.5 

3 0.1 16.1 106.0 5.5 

4 0.1 16.1 106.0 5.5 

5 36.2 29.8 106.0 7.1 

6 36.2 29.8 15.5 7.1 

7 36.2 29.8 15.5 7.1 

8 36.2 29.8 15.5 7.1 

9 36.2 29.8 15.5 7.1 

10 36.2 29.8 15.5 7.1 

11 19.0 11.5 151.7 1.5 

12 19.0 11.5 151.7 1.5 

13 19.0 11.5 151.7 1.5 

14 19.0 11.5 151.7 1.5 

15 19.0 11.5 151.7 1.5 

16 19.0 11.5 151.7 1.5 

17 11.9 28.7 20.0 12.7 

18 11.9 28.7 20.0 12.7 

19 11.9 28.7 20.0 12.7 

20 11.9 28.7 20.0 12.7 

21 11.9 28.7 20.0 12.7 

22 11.9 28.7 20.0 12.7 

23 16.1 3.5 5.5 1.5 

24 16.1 3.5 5.5 1.5 
Page 16 of 38 

 An example of the specific analyses used to determine the flux values for each site is presented in 

Table 6 for plot 1 in this study. Analyses were completed using either the indirect method or the integrated 

horizontal flux method as appropriate. Graphs which illustrate the differences between the flux estimates 

calculated by the investigators and those calculated by the Agency have also been developed and an 

example is presented in Figure 11. In general there is good agreement between the values calculated by the 

investigators and those calculated by the Agency. The Agency flux profiles have been used to estimate 

risks using the PERFUM model because the Agency corrected measured air concentrations for average field 

recovery. 

More detailed information can be provided if needed concerning the details of the flux calculations. 

It should be mentioned that the flux calculations in this study were complex because there was poor 

correlation in the regression analysis required by the Integrated Horizontal Flux (IHF) method. The 

investigators tackled this problem by using interpolated concentration values for all those periods that had 

constant concentration across the different heights. Since, the regression for the IHF method requires a 

minimum of 3 points, the Agency used the outlier removal method which removes at least one of the four 

concentration values to improve the overall regression. This approach significantly improved the regression 

for several periods. For all the periods that could not be modified using the outlier removal method, the 

LOQ value for the air concentration for that period was used to calculate flux by multiplying the LOQ value 

by fetch for that period. In the critical earlier time periods where more intense exposures are more likely the 

outlier removal method was appropriate. 

Table 6: Flux Calculation Details For Florida Field Plot 1 (MRID 481076) 

Period Duration 

Estimated flux 

μg/m2-sec 

Agency Registrant 

1 1/15/2010 9:45 - 13:00 0.06 5.10 

2 1/15/2010 13:00 - 19:00 19.79 21.52 

3 1/15/2010 19:00 - 01:00 10.42 12.28 

4 1/16/2010 01:00 - 07:00 6.47 6.55 

5 1/16/2010 07:00 - 13:00 8.82 9.30 

6 1/16/2010 13:00 - 19:00 16.34 15.57 

7 1/16/2010 19:00 - 01:00 6.34 7.10 

8 1/17/2010 01:00 - 07:00 15.68 16.92 

9 1/17/2010 07:00 - 19:00 1.88 0.10 

10 1/17/2010 19:00 - 07:00 0.11 0.20 

11 1/18/2010 07:00 - 19:00 1.18 1.34 

12 1/18/2010 19:00 - 07:00 0.26 0.33 

13 1/19/2010 07:00 - 19:00 0.80 0.97 

14 1/19/2010 19:00 - 07:00 0.65 0.67 

15 1/20/2010 07:00 - 19:00 0.99 1.17 

16 1/20/2010 19:00 - 07:00 0.24 0.23 

17 1/21/2010 07:00 - 19:00 0.46 1.16 

18 1/21/2010 19:00 - 07:00 0.94 0.07 

19 1/22/2010 07:00 - 19:00 1.00 0.08 

20 1/22/2010 19:00 - 07:00 1.02 0.02 

21 1/23/2010 07:00 - 19:00 0.94 0.07 

22 1/23/2010 19:00 - 07:00 1.04 0.07 

23 1/24/2010 07:00 - 20:00 0.36 0.11 

24 1/24/2010 20:00 - 07:45 0.95 0.12 
Page 17 of 38 

Table 6: Flux Calculation Details For Florida Field Plot 1 (MRID 481076) 

Period Duration 

Estimated flux 

μg/m2-sec 

Agency Registrant 

25 1/15/2010 9:45 - 13:00 0.06 5.10 

26 1/15/2010 13:00 - 19:00 19.79 21.52 

27 1/15/2010 19:00 - 01:00 10.42 12.28 

28 1/16/2010 01:00 - 07:00 6.47 6.55 

29 1/16/2010 07:00 - 13:00 8.82 9.30 

30 1/16/2010 13:00 - 19:00 16.34 15.57 

31 1/16/2010 19:00 - 01:00 6.34 7.10 

32 1/17/2010 01:00 - 07:00 15.68 16.92 

MeBr Flux from Field1

0.0

5.0

10.0

15.0

20.0

25.0

1/14/2010 1/16/2010 1/18/2010 1/20/2010 1/22/2010 1/24/2010 1/26/2010

Time

Flux (μg/m2-sec)

Versar

Registrant

Figure 11: Methyl Bromide Flux Estimates From Florida Field 1 (MRID 481076-01) 

Comparison of EPA and Registrant Calculated Values 

 This study was designed to elucidate the impacts of various control measures on methyl bromide 

emissions. The measure evaluated in this study was the use of a barrier film. Additionally, care was 

exerted to ensure that applications occurred that are as compliant as possible with the good agricultural 

practices that have been under development for fumigant applications. The results indicate that the 

measures attempted in this research reduced peak emission rates compared to current typical practices and 

also impacted cumulative emissions (Figures 12 and 8, respectively). Figure 12 presents the emissions 

profiles used in the previous assessment for current practices (i.e., bedded tarped, and hot gas) and compares 

them to the emissions quantified in this study for the first 24 hours after application. The emission profiles 

have all been adjusted to an application rate of 100 lb methyl bromide/treated acre to ensure a valid 

comparison. The profiles with the lines and dots represent the data from this study. The results indicate the 

barrier tarp reduces emissions compared to the previously used profiles. 

Finally, the ability of high barrier tarps to substantively retain methyl bromide over time is 

illustrated by the information presented in Appendix A. Once tarp cutting occurred after the hot gas 

applications it is clear that retained methyl bromide is released at higher levels compared to the periods just 

prior to that operation and in some cases flux is similar to values immediately after application. Thus, the 

risks associated with such a phenomena appear to be similar to or less than predicted for periods 

immediately after application. However, there are potential impacts on the duration of a buffer zone or the 

restricted entry interval for workers. 
Page 18 of 38 

Methyl Bromide Flux - Normalized To 100 lb/acre

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

Hours

Flux (ug/m2-s)

Bedded, Tarped

Hot Gas

1 EVOH Tarped

Raised Bed

2 EVOH Hot

Gas

Figure 12: Comparison of MBIP Flux From Florida Research Plots (MRID 481076-01) and Existing Flux 

Estimates For Similar Application Methods (Normalized to 100 lb ai/acre) For 1st 24 Hours After Application
Page 19 of 38 

 4.0 1st Principles Factors 

The 1st principles factors that impact emissions include subsurface soil conditions, application 

methods/parameters, film types, and many others.8 The Agency has attempted to characterize conditions 

that tend to reduce emission rates which are consistent with the proper cultivation of a crop of interest such 

as strawberries or tomatoes. The practices are referred to as Good Agricultural Practices or GAPs. GAPS 

include guidelines on proper field preparation, considerations for film selection, and discussions of the 

importance of maintaining proper soil moisture. This section presents the data which were included in the 

MBIP study reports. The data from California are presented in Section 4.1 while the data from Florida are 

presented in Section 4.2.9

4.1 California Study Results (MRID 480060-01) 

At the California site soil samples were collected prior to application on June 2, 2009 and following 

the end of air monitoring on June 13, 2009. Core samples were collected at five depths at a minimum of 

three locations across each field. For each field, samples from the same depth were combined. The cores 

were collected from the following depths: 0-3, 3-6, 6-9, 9-12, 12-18, and 18-24 inches. Each soil sample 

consisted of approximately 1 pound of soil. The soil samples were sealed in soil sampling plastic bags. The 

soil samples from each field were analyzed for texture, organic matter and soil moisture. PVC cores were 

used to sample the soil for bulk density determination. Fields 1 and 2 were relatively dry the day before 

fumigation. Therefore, these two fields were irrigated on June 1, 2010 (the day before fumigation) with a 

water truck and disked before fumigant application. 

Soil Conditions:

 Table 7 summarizes the conditions during the conduct of the study for each field plot at varied 

depths down to 24 inches below the surface. It appears that the study was conducted in compliance with the 

current recommendations for good agricultural practices. The field conditions also reflect what could be 

considered typical for fumigant applications in that area of California in that use season. 

Table 7: Soil Condition Summary For Wasco California Field Plots 

Sample Depth 

(inches) 

Moisture Soil Characterization Approximate 

Soil Temperatures (deg F) 

(% by wgt) (% Field 

Capacity) 

(% Organic 

Matter) 

Soil Type Minimum Maximum 

Field Plot 1 – HDPE Shallow Broadcast 

0-3 5.2 48 0.74 Loamy sand 68 113 

3-6 7.6 69 0.80 73 105 

6-9 8.2 80 0.63 78 97 

9-12 9.3 93 0.51 80 93 

12-18 9.1 92 0.43 Not reported 

18-24 8.7 87 0.34 

Field Plot 2 – EVOH Shallow Broadcast 

0-3 5.5 50 0.85 Loamy sand 68 109 

3-6 7.3 68 0.92 72 102 

6-9 7.8 77 0.86 74 95 

 

8 Factors Which Impact Soil Fumigant Emissions - Evaluation For Use In Soil Fumigant Buffer Zone Credit Factor Approach (D306857), 

Authors: Dawson and Smith, 6/9/08

9 A separate memo will be completed which addresses the issue of 1st principles factors and their relative impacts. This document will address 

information from all of the studies submitted to the Agency recently as a result of the RED documents for several fumigants.
Page 20 of 38 

Table 7: Soil Condition Summary For Wasco California Field Plots 

Sample Depth 

(inches) 

Moisture Soil Characterization Approximate 

Soil Temperatures (deg F) 

(% by wgt) (% Field 

Capacity) 

(% Organic 

Matter) 

Soil Type Minimum Maximum 

9-12 9.1 90 0.66 75 95 

12-18 8.3 83 0.27 Not reported 

18-24 9.2 92 0.34 

Field Plot 3 – EVOH & KTS Shallow Broadcast 

0-3 5.3 48 0.72 Loamy sand 70 105 

3-6 7.9 70 0.57 75 96 

6-9 7.7 77 0.35 78 91 

9-12 8.3 82 0.38 79 87 

12-18 7.8 79 0.30 Not reported 

18-24 7.1 72 0.26 

Field Plot 4 – EVOH Deep Strip 

0-3 5.8 53 0.51 Loamy sand 73 110 

3-6 7.2 66 0.44 77 102 

6-9 7.7 77 0.28 80 96 

9-12 8.4 82 0.31 81 92 

12-18 7.4 72 0.26 Not reported 

18-24 7.9 77 0.21 

Field Plot 5 – EVOH Deep Broadcast 

0-3 6.4 59 0.58 Loamy sand 71 110 

3-6 6.9 64 0.57 77 102 

6-9 7.7 77 0.42 78 98 

9-12 8.0 82 0.34 79 92 

12-18 9.3 91 0.23 Not reported 

18-24 8.7 87 0.18 

Application Methods:

 Applications in field plots 1 through 3 were completed using a Noble plow (Figure 13) at a depth of 

12 inches. The Noble Plow is a plow that consists of horizontal v-shaped blades mounted by a vertical arm 

of the tool bar that injects fumigants laterally to a depth of 12 inches beneath the soil surface. The Noble 

Plow has two 32-inch wide plows on spacing not exceeding 48 inches. As described above, the key 

differences between plots 1 through 3 were the use of a barrier film (plots 2 and 3) and the reactive 

adjuvant, KTS, in plot 3. 

Figure 13: Noble Plow Configuration Used In Wasco California Field Plots 
Page 21 of 38 

Applications in field plots 4 and 5 were completed using a forward swept chisel (Figure 14) at a 

depth of 18 inches. The fumigant release point was on the rear of each shank near the bottom of the shank. 

As described above, the key difference between plots 4 and 5 was that site 4 was a strip fumigation while a 

broadcast application was completed at site 5. 

Figure 14: Forward Swept Chisel Configuration Used In Wasco California Field Plots 

Tarp Information:

Fresh (unused) tarp samples were collected from each roll used in this study. Also, five tarp samples 

were collected from each field after tarp splitting. Tarp permeability was estimated by determining the mass 

transfer coefficient (cm/hr) using static permeability cells. The average results for the mass transfer 

coefficient and tarp thickness for the five fields are summarized below in Table 8. The permeability of the 

tarps was evaluated at 1000 ppm for each of methyl bromide. The physical stress of deploying the films 

using commercial equipment and cultural practices onto the test fields during application had only nominal 

effects on the mass transfer coefficients determined for the polyethylene and VaporSafeTM film samples. 

[Please refer back to footnote 2 (pg 3) that describes issues raised by the tarp manufacturer indicating a 

more appropriate description of the barrier tarps used in this study as EVALTM rather than VaporSafe.] 

Table 8: Thickness & Mass Transfer Coefficients Of Tarps Used In Wasco California Field Plots For Methyl Bromide 

Field Plot Film Type Film Thickness (mil) Mass Transfer Coefficients (cm/hr) 

Directly Off Roll After Field Use 

1 Polyethylene 0.9 3.95 3.97 

2 Vapor Safe (EVOH) 1.0 0.0035 0.0039 

3 Vapor Safe (EVOH) 1.0 0.0037 0.0044 

4 Vapor Safe (EVOH) 1.0 0.0029 0.0039 

5 Vapor Safe (EVOH) 1.0 0.0022 0.0030 
Page 22 of 38 

4.2 Florida Study Results (MRID 481076-01)

At the Florida site soil samples were collected prior to application on January 15, 2010 and 

following the end of air monitoring on January 25, 2010. Core samples were collected at four depths at two 

locations across each field. For each field, samples from the same depth were combined. The cores were 

collected from the following depths: 0-3, 3-6, 6-9, and 9-12 inches. Each soil sample consisted of 

approximately 1 pound of soil. The soil samples were sealed in soil sampling plastic sample jars. The soil 

samples from each field were analyzed for texture, bulk density, organic matter and soil moisture. 

Soil Conditions:

Table 9 summarizes the conditions during the conduct of the study for each field plot at varied 

depths down to 12 inches below the surface. It appears that the study was conducted in compliance with the 

current recommendations for good agricultural practices. The field conditions also reflect what could be 

considered typical for fumigant applications in that area of Florida in that use season. 

Table 9: Soil Condition Summary For Fort Pierce Florida Field Plots 

Sample Depth 

(inches) 

Moisture Soil Characterization Approximate 

Soil Temperatures (deg F) 

(% by wgt) (% Field 

Capacity) 

(% Organic 

Matter) 

Soil Type Minimum Maximum 

Field Plot 1 – Tarped Raised Bed 

0-3 11.3 134.1 3.1 Sand 60 82 

3-6 11.6 136.5 3.5 61 75 

6-9 11.6 137.7 1.4 58 73 

9-12 12.6 152.8 2.3 58 73 

Field Plot 2 – Hot Gas 

0-3 8.9 108.5 1.5 Sand 57 81 

3-6 11.0 145.3 1.6 58 74 

6-9 13.3 153.2 1.2 58 72 

9-12 13.0 170.6 1.1 58 72 

Under tarp for plot 1 (53-95 deg) and plot 2 (50-120 deg). 

Application Methods:

 The application in field plot 1 was completed using a John Deere 6430 tractor equipped with a 

Kennco-style bedder (Figure 15). The application equipment consisted of a standard Kennco-style bedder 

equipped with 3 extra-long back swept gas knives with the orifices located just under the press area of the 

bedder. Attached to the rear of the bedder was a plastic layer with room for 2 rolls of film as well as a 

spooler for drip irrigation tubing, if required. The gas knives were positioned to place the fumigant at the 

bottom of the bed (10 inches deep) and were spaced 12 inches apart. Rows were spaced 5.5 feet apart on 

center and the beds were 10 inches tall with a 32 inch wide bed top. Beds were 40 inches wide at the base 

and 36 inches was used by the investigators for application calibration calculations. 
Page 23 of 38 

Figure 15: Tarped Raised Bed Application Configuration Used In Fort Pierce Florida Field Plot 

The application in field plot 2 was completed using a hot-gas arrangement (Figure 16). The 

boundary of the treated area was trenched to a depth of 12 to 14 inches. Drip tapes were placed under the 

tarp (12” space between emitters) 9 feet apart from each other. Once the fumigant had heated to the gas 

phase in the kettles the delivery ball valves at each line off of the manifold were opened and the gas rapidly 

deployed through the tubing to the drip tubing in the field. The initial kettle temperature was ~155° F. 

Application flow rate was controlled by a ball valve on the cylinder, the nitrogen pressure (the propellant) 

and the kettle temperature. Initial nitrogen pressure was 5 psi and it was slowly increased to 30 psi. The 

flow rate was estimated at 3lb/minute based on weight change on the scale of the cylinder. 

Figure 16: Hot Gas Application Configuration Used In Fort Pierce Florida Field Plot 
Page 24 of 38 

5.0 Risk Analysis 

 The risk estimates calculated based on the MBIP monitoring studies are summarized in this section. 

The risks associated with the data from California are presented in Section 5.1 while the risk estimates from 

Florida are summarized in Section 5.2. All risk estimates were calculated using the same hazard inputs and 

PERFUM modeling approaches as described in the previous risk assessment for methyl bromide.10 A 

summary of the results for the Ventura weather station for a 40 acre field at varied rates from the 2007 

assessment is presented in Table 10 below for comparison purposes with the results for the new studies. 

Table 10: Comparison Of Results For Methyl Bromide PERFUM Buffer Distributions Based On A 40 Acre Square 

Field, Ventura California Weather Data, And All Flux Profiles At A UF=30 (Source D337288, 2007) 

Percentile

s 

100% (430 lb/Acre) 75% (323 lb/Acre) 50% (215 lb/Acre) 25% (108 lb/Acre) 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Flux Profile = Tarped Application Method 

50 110 0 40 0 5 0 0 0 

75 230 5 130 5 25 0 0 0 

90 350 70 220 25 90 5 5 0 

95 430 150 280 80 125 5 5 0 

99 555 330 390 215 200 90 5 5 

99.9 725 510 500 355 265 190 20 5 

99.99 760 680 555 485 305 265 60 45 

Flux Profile = Deep Untarped Application Method 

50 165 0 85 0 5 0 0 0 

75 305 20 195 5 70 0 0 0 

90 450 105 305 55 140 5 5 0 

95 530 200 370 125 185 40 5 0 

99 695 420 490 285 290 140 45 5 

99.9 875 635 630 445 365 260 110 45 

99.99 935 850 700 605 430 350 115 100 

Flux Profile = Hot Gas Application Method 

50 505 25 360 10 200 5 35 0 

75 705 135 510 95 305 50 85 5 

90 985 315 725 235 450 135 150 25 

95 1185 450 880 340 565 210 210 60 

99 1440 790 1250 605 795 395 355 150 

99.9 1440 1285 1440 970 1205 655 500 315 

99.99 1440 1440 1440 1275 1330 845 545 455 

Flux Profile = Bedded Tarped Application Method 

50 135 0 70 0 10 0 0 0 

75 200 30 115 10 40 5 5 0 

90 295 95 190 50 80 10 5 0 

95 395 145 260 90 120 30 5 5 

99 670 290 525 195 305 95 85 5 

99.9 1225 590 925 440 555 285 210 85 

99.99 1305 1005 955 730 565 480 230 205 

 

10 Methyl Bromide: Phase 5 Health Effects Division (HED) Human Health Risk Assessment For Soil, Greenhouse, and 

Residential/Structural Uses. PC Code: 053201, DP Barcode: D337288 (4/10/07) Authors: Mendez & Dawson 
Page 25 of 38 

 5.1 California Study Results (MRID 480060-01) 

The risk estimates calculated for the MBIP monitoring data from the California monitoring plots are 

summarized below in Tables 11 and 12 using a 40 acre field and the Ventura weather data. The PERFUM 

modelling results based on the Ventura weather dataset have been summarized for a 40 acre field using the 

same application rates to allow for a more direct comparison with the results presented in the 2007 risk 

assessment because this scenario was also used for illustrative purposes in that assessment. Results have 

been calculated using a variety of field sizes (1 to 160 acres) and a total of 6 weather data sources (e.g., 

Bradenton FL is another location). These are available in the form of PERFUM output files. A limited 

number of outputs have been summarized herein for summary/illustrative purposes. Table 11 presents the 

PERFUM buffer distributional outputs for all of the field plots in California for the 24 hour period 

immediately after application. Both maximum and whole field buffer results are presented. There is one 

additional set of outputs which have been included which are based on the actual application rates in each 

field plot. The results for field plot 1 were intended to serve as a comparison to common current practices 

and essentially are directly comparable to those presented above for the existing 2007 assessment. The 

other research plots evaluated measures to reduce emission levels. Results indicate a combination of barrier 

films and a reactive adjuvant (i.e., KTS) or injection depth clearly reduce emissions and the length of 

predicted buffer zones. 

Table 11: Methyl Bromide PERFUM Buffer Distributions Based On A 40 Acre Square Field, Ventura California Weather Data, 

And All Flux Profiles From The Wasco California MBIP Study Plots 

Percentile 

of Exposure 

100% (430 lb/Acre) 75% (323 lb/Acre) 50% (215 lb/Acre) 

Study Rate 

(178-203 lb/Acre) 25% (108 lb/Acre) 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Field Plot 1 - HDPE Shallow Broadcast (Treated at 189.1 lb methyl bromide/treated acre) 

50 125 5 65 0 5 0 5 0 0 0 

75 185 40 105 15 30 5 15 0 5 0 

90 275 95 175 50 70 5 90 5 5 0 

95 345 140 230 80 95 20 80 10 5 5 

99 600 265 430 175 235 80 190 60 60 5 

99.9 920 505 655 380 365 230 300 195 140 65 

99.99 1440 835 850 605 640 395 580 355 290 210 

Field Plot 2- EVOH Shallow Broadcast (180.3 lb methyl bromide/treated acre) 

50 5 0 0 0 0 0 0 0 0 0 

75 5 0 5 0 0 0 0 0 0 0 

90 5 0 5 0 0 0 0 0 0 0 

95 30 5 5 5 5 0 0 0 0 0 

99 140 25 65 5 5 0 5 0 0 0 

99.9 270 140 175 85 75 20 50 5 5 0 

99.99 555 330 400 255 220 160 170 125 5 5 

Field Plot 3- EVOH & KTS Shallow Broadcast(177.9 lb methyl bromide/treated acre) 

50 0 0 0 0 0 0 0 0 0 0 

75 0 0 0 0 0 0 0 0 0 0 

90 0 0 0 0 0 0 0 0 0 0 

95 0 0 0 0 0 0 0 0 0 0 

99 5 0 0 0 0 0 0 0 0 0 

99.9 15 5 5 0 0 0 0 0 0 0 
Page 26 of 38 

Table 11: Methyl Bromide PERFUM Buffer Distributions Based On A 40 Acre Square Field, Ventura California Weather Data, 

And All Flux Profiles From The Wasco California MBIP Study Plots 

Percentile 

of Exposure 

100% (430 lb/Acre) 75% (323 lb/Acre) 50% (215 lb/Acre) 

Study Rate 

(178-203 lb/Acre) 25% (108 lb/Acre) 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

99.99 55 45 5 5 5 5 0 0 0 0 

Field Plot 4- EVOH Deep Strip (202.6 lb methyl bromide/treated acre) 

50 0 0 0 0 0 0 0 0 0 0 

75 0 0 0 0 0 0 0 0 0 0 

90 0 0 0 0 0 0 0 0 0 0 

95 5 0 0 0 0 0 0 0 0 0 

99 5 5 5 0 0 0 0 0 0 0 

99.9 5 5 5 5 0 0 0 0 0 0 

99.99 15 5 5 5 0 0 0 0 0 0 

Field Plot 5- EVOH Deep Broadcast(181.1 lb methyl bromide/treated acre) 

50 0 0 0 0 0 0 0 0 0 0 

75 0 0 0 0 0 0 0 0 0 0 

90 0 0 0 0 0 0 0 0 0 0 

95 0 0 0 0 0 0 0 0 0 0 

99 5 0 0 0 0 0 0 0 0 0 

99.9 5 5 5 0 0 0 0 0 0 0 

99.99 5 5 5 5 0 0 0 0 0 0 

Table 12 below reinforces the conclusions drawn based on the buffer outputs described above. It is only 

when values at the highest percentiles of exposure are considered that risks appear to be of concern. (e.g., 

Plot 1, MOE = 5 at 10 meters at the 99.99th percentile). Table 12 presents the air concentrations at specific 

distances from the edge of the treated fields considered in PERFUM for the 24 hour period immediately 

after application. Again, for comparative purposes results for a 40 acre field based on the Ventura weather 

data are presented. Results for distances of 10 to 150 meters from the field edge were selected but results 

for additional distances of interest (i.e., a total of 30 points) up to 1440 meters from the field are available.11 

Table 12: Wasco Califonria Risks Based On Ring Concentrations From PERFUM – 40 Acre Field and Ventura Weather Data 

 [MeBr Air] (ug/m3) Margins of Exposure 

Percentile 

of 

Exposure 10m 30m 50m 100m 150m 10m 30m 50m 100m 150m 

Plot 1 (HDPE Shallow Boradcast) - At Highest Evaluated Application Rate (430 lb methyl bromide/treated/acre) 

50 949.0 611.0 429.0 195.0 91.0 41 64 91 199 427 

75 1859.0 1417.0 1131.0 741.0 507.0 21 27 34 52 77 

90 2509.0 2041.0 1729.0 1261.0 975.0 15 19 22 31 40 

95 2925.0 2457.0 2093.0 1547.0 1235.0 13 16 19 25 31 

97 3263.0 2769.0 2405.0 1781.0 1417.0 12 14 16 22 27 

99 4199.0 3601.0 3133.0 2353.0 1885.0 9 11 12 17 21 

 

11 The current requirements for buffer zone duration is 48 hours and entry restricted interval is 5 days. Based on the available flux information, 

it appears that the TIF retains methyl bromide and some increased emissions are noted associated with tarp cutting operations that occurred 6 

days after application in this study. However, the level of emissions is lower than observed (about 1⁄2 on average of peak) or similar to (deep 

broadcast – field 5 only) that immediately after application during tarp cutting. This consideration along with the risk estimates reported in 

Table 11 and 12 should be considered related to refinement of the restricted entry interval. 
Page 27 of 38 

Table 12: Wasco Califonria Risks Based On Ring Concentrations From PERFUM – 40 Acre Field and Ventura Weather Data 

 [MeBr Air] (ug/m3) Margins of Exposure 

Percentile 

of 

Exposure 10m 30m 50m 100m 150m 10m 30m 50m 100m 150m 

99.9 7189.0 6409.0 5629.0 4251.0 3419.0 5 6 7 9 11 

Plot 1 (HDPE Shallow Boradcast) - At Study Application Rate (189 lb methyl bromide/treated/acre) 

50 417.3 268.7 188.7 85.8 40.0 93 145 206 453 970 

75 817.5 623.2 497.4 325.9 223.0 47 62 78 119 174 

90 1103.4 897.6 760.4 554.5 428.8 35 43 51 70 91 

95 1286.3 1080.5 920.4 680.3 543.1 30 36 42 57 71 

97 1435.0 1217.7 1057.6 783.2 623.2 27 32 37 50 62 

99 1846.6 1583.6 1377.8 1034.8 829.0 21 25 28 38 47 

99.9 3161.5 2818.5 2475.5 1869.5 1503.6 12 14 16 21 26 

Plot 2 (EVOH Shallow Broadcast) - At Highest Evaluated Application Rate (430 lb methyl bromide/treated/acre) 

50 195.0 117.0 91.0 39.0 13.0 199 332 427 996 2987 

75 637.0 455.0 351.0 195.0 117.0 61 85 111 199 332 

90 897.0 715.0 585.0 403.0 299.0 43 54 66 96 130 

95 1027.0 845.0 715.0 507.0 403.0 38 46 54 77 96 

97 1157.0 949.0 793.0 585.0 455.0 34 41 49 66 85 

99 1495.0 1261.0 1079.0 793.0 611.0 26 31 36 49 64 

99.9 2639.0 2327.0 2041.0 1521.0 1235.0 15 17 19 26 31 

Plot 2 (EVOH Shallow Broadcast) - At Study Application Rate (180.3 lb methyl bromide/treated/acre) 

50 81.8 49.1 38.2 16.4 5.5 475 792 1018 2375 7124 

75 267.1 190.8 147.2 81.8 49.1 145 204 264 475 792 

90 376.1 299.8 245.3 169.0 125.4 103 130 158 230 310 

95 430.6 354.3 299.8 212.6 169.0 90 110 130 183 230 

97 485.1 397.9 332.5 245.3 190.8 80 98 117 158 204 

99 626.9 528.7 452.4 332.5 256.2 62 73 86 117 152 

99.9 1106.5 975.7 855.8 637.8 517.8 35 40 45 61 75 

Plot 3 (EVOH & KTS Shallow Broadcast) - At Highest Evaluated Application Rate (430 lb methyl bromide/treated/acre) 

50 65.0 39.0 13.0 13.0 13.0 597 996 2987 2987 2987 

75 221.0 169.0 117.0 65.0 39.0 176 230 332 597 996 

90 325.0 247.0 221.0 143.0 117.0 119 157 176 272 332 

95 377.0 299.0 247.0 195.0 143.0 103 130 157 199 272 

97 429.0 351.0 299.0 221.0 169.0 91 111 130 176 230 

99 559.0 455.0 403.0 273.0 221.0 69 85 96 142 176 

99.9 871.0 793.0 689.0 533.0 403.0 45 49 56 73 96 

Plot 3 (EVOH & KTS Shallow Broadcast) - At Study Application Rate (177.9 lb methyl bromide/treated/acre) 

50 26.9 16.1 5.4 5.4 5.4 1444 2407 7220 7220 7220 

75 91.4 69.9 48.4 26.9 16.1 425 555 802 1444 2407 

90 134.5 102.2 91.4 59.2 48.4 289 380 425 656 802 

95 156.0 123.7 102.2 80.7 59.2 249 314 380 481 656 

97 177.5 145.2 123.7 91.4 69.9 219 267 314 425 555 

99 231.3 188.2 166.7 112.9 91.4 168 206 233 344 425 

99.9 360.4 328.1 285.1 220.5 166.7 108 118 136 176 233 

Plot 4 (EVOH Deep Strip) - At Highest Evaluated Application Rate (430 lb methyl bromide/treated/acre) 

50 143.0 91.0 65.0 13.0 13.0 272 427 597 2987 2987 

75 273.0 195.0 169.0 91.0 65.0 142 199 230 427 597 

90 429.0 351.0 299.0 221.0 169.0 91 111 130 176 230 
Page 28 of 38 

Table 12: Wasco Califonria Risks Based On Ring Concentrations From PERFUM – 40 Acre Field and Ventura Weather Data 

 [MeBr Air] (ug/m3) Margins of Exposure 

Percentile 

of 

Exposure 10m 30m 50m 100m 150m 10m 30m 50m 100m 150m 

95 533.0 481.0 429.0 325.0 273.0 73 81 91 119 142 

97 611.0 559.0 507.0 403.0 325.0 64 69 77 96 119 

99 767.0 715.0 637.0 507.0 429.0 51 54 61 77 91 

99.9 1027.0 949.0 871.0 715.0 585.0 38 41 45 54 66 

Plot 4 (EVOH Deep Strip) - At Study Application Rate (202.6 lb methyl bromide/treated/acre) 

50 67.4 42.9 30.6 6.1 6.1 576 906 1268 6339 6339 

75 128.6 91.9 79.6 42.9 30.6 302 423 488 906 1268 

90 202.1 165.4 140.9 104.1 79.6 192 235 276 373 488 

95 251.1 226.6 202.1 153.1 128.6 155 171 192 254 302 

97 287.9 263.4 238.9 189.9 153.1 135 147 163 204 254 

99 361.4 336.9 300.1 238.9 202.1 107 115 129 163 192 

99.9 483.9 447.1 410.4 336.9 275.6 80 87 95 115 141 

Plot 5 (EVOH Deep Broadcast) - At Highest Evaluated Application Rate (430 lb methyl bromide/treated/acre) 

50 91.0 65.0 39.0 13.0 13.0 427 597 996 2987 2987 

75 195.0 169.0 117.0 65.0 39.0 199 230 332 597 996 

90 299.0 247.0 221.0 143.0 117.0 130 157 176 272 332 

95 377.0 325.0 273.0 221.0 169.0 103 119 142 176 230 

97 429.0 377.0 325.0 247.0 195.0 91 103 119 157 199 

99 533.0 481.0 429.0 325.0 273.0 73 81 91 119 142 

99.9 767.0 689.0 611.0 481.0 403.0 51 56 64 81 96 

Plot 5 (EVOH Deep Broadcast) - At Study Application Rate (181.1 lb methyl bromide/treated/acre) 

50 38.3 27.4 16.4 5.5 5.5 1013 1418 2364 7092 7092 

75 82.1 71.2 49.3 27.4 16.4 473 546 788 1418 2364 

90 125.9 104.0 93.1 60.2 49.3 308 373 417 645 788 

95 158.8 136.9 115.0 93.1 71.2 245 284 338 417 546 

97 180.7 158.8 136.9 104.0 82.1 215 245 284 373 473 

99 224.5 202.6 180.7 136.9 115.0 173 192 215 284 338 

99.9 323.0 290.2 257.3 202.6 169.7 120 134 151 192 229 

 5.2 Florida Study Results (MRID 481076-01) 

 The risk estimates calculated for the MBIP monitoring data from the Florida monitoring plots are 

summarized below in Tables 13 and 14 using a 40 acre field and the Ventura weather data. The PERFUM 

modelling results based on the Ventura weather dataset have been summarized for a 40 acre field using the 

same application rates in this table to allow for a more direct comparison with the results presented in the 

2007 risk assessment because this scenario was also used for illustrative purposes in that assessment. 

Results have been calculated using a variety of field sizes (1 to 160 acres) and a total of 6 weather data 

sources (e.g., Bradenton FL is another location). These are available in the form of PERFUM output files. 

A limited number of outputs have been summarized herein for summary/illustrative purposes. Table 13 

presents the PERFUM buffer distributional outputs for all of the field plots in Florida for the 24 hour period 

immediately after application. Both maximum and whole field buffer results are presented. There is one 

additional set of outputs which have been included which are based on the actual application rates in each 

field plot. No plots at the Florida site compared directly with the scenarios considered in the previous 
Page 29 of 38 

assessment as described above. Both scenarios used a TIF with no other apparent changes from current 

cultural practices outside of addressing compliance with prescribed good agricultural practices. 

Table 13: Methyl Bromide PERFUM Buffer Distributions Based On A 40 Acre Square Field, Ventura California Weather Data, 

And All Flux Profiles From The Fort Pierce Florida MBIP Study Plots 

Percentile 

of Exposure 

Max (430 lb/Acre) 75% (323 lb/Acre) 

Study Rate 

(235 lb/Acre) 50% (215 lb/Acre) 25% (108 lb/Acre) 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Max 

Distance 

Whole 

Field 

Field Plot 1 – EVOH Tarped Raised Bed (235 lb methyl bromide/treated acre) 

50 0 0 0 0 0 0 0 0 0 0 

75 0 0 0 0 0 0 0 0 0 0 

90 0 0 0 0 0 0 0 0 0 0 

95 0 0 0 0 0 0 0 0 0 0 

99 0 0 0 0 0 0 0 0 0 0 

99.9 0 0 0 0 0 0 0 0 0 0 

99.99 5 5 0 0 0 0 0 0 0 0 

Field Plot 2- EVOH Hot Gas (426 lb methyl bromide/treated acre) 

50 5 0 0 0 

See 430 

application rate 

block 

0 0 0 0 

75 35 0 5 0 0 0 0 0 

90 105 5 30 0 5 0 0 0 

95 150 20 65 5 5 0 0 0 

99 240 110 130 40 5 5 0 0 

99.9 310 220 195 120 55 10 5 0 

99.99 335 290 200 175 55 55 5 5 

Table 14 below reinforces the conclusions drawn based on the buffer outputs described above. It is only 

when values at the highest percentiles of exposure are considered that risks appear to be of concern. (e.g., 

Plot 1, MOE = 5 at 10 meters at the 99.99th percentile). Table 14 presents the air concentrations at specific 

distances from the edge of the treated fields considered in PERFUM. Again, for comparative purposes 

results for a 40 acre field based on the Ventura weather data are presented. Results for distances of 10 to 

150 meters from the field edge were selected but results for additional distances of interest (i.e., a total of 30 

points) up to 1440 meters from the field are available.12 [Note: For site 1 (tarped raised bed) the air 

concentrations for the second day were slightly higher than day 1 so they have been used as the basis for 

this analysis.] 

 

12 The current requirements for buffer zone duration is 48 hours and entry restricted interval is 5 days. Based on the available flux information, 

it appears that the TIF retains methyl bromide and some increased emissions are noted associated with tarp cutting operations that occurred 7 

days after application in this study for the hot gas treatment. The level of emissions is similar to that immediately after application. This 

consideration along with the risk estimates reported in Table 13 and 14 should be considered related to refinement of the restricted entry 

interval. Hole punching was not completed during the study at the for the raised bed field since it would not typically be done until 

21 to 28 days after application just before planting. 
Page 30 of 38 

Table 14: Wasco Califonria Risks Based On Ring Concentrations From PERFUM – 40 Acre Field and Ventura Weather Data 

 [MeBr Air] (ug/m3) Margins of Exposure 

Percentile 

of 

Exposure 10m 30m 50m 100m 150m 10m 30m 50m 100m 150m 

Plot 1 – EVOH Tarped Raised Bed At Highest Evaluated Application Rate (430 lb methyl bromide/treated/acre) 

50 65.0 39.0 13.0 13.0 13.0 597 996 2987 2987 2987 

75 143.0 117.0 91.0 65.0 39.0 272 332 427 597 996 

90 247.0 195.0 169.0 117.0 91.0 157 199 230 332 427 

95 299.0 273.0 247.0 195.0 143.0 130 142 157 199 272 

97 351.0 325.0 299.0 221.0 195.0 111 119 130 176 199 

99 429.0 403.0 351.0 299.0 247.0 91 96 111 130 157 

99.9 585.0 533.0 507.0 403.0 325.0 66 73 77 96 119 

Plot 1 – EVOH Tarped Raised Bed At Study Application Rate (235 lb methyl bromide/treated/acre) 

50 35.5 21.3 7.1 7.1 7.1 1093 1822 5465 5465 5465 

75 78.2 63.9 49.7 35.5 21.3 497 607 781 1093 1822 

90 135.0 106.6 92.4 63.9 49.7 288 364 420 607 781 

95 163.4 149.2 135.0 106.6 78.2 238 260 288 364 497 

97 191.8 177.6 163.4 120.8 106.6 202 219 238 321 364 

99 234.5 220.2 191.8 163.4 135.0 166 176 202 238 288 

99.9 319.7 291.3 277.1 220.2 177.6 121 133 140 176 219 

Plot 2 - EVOH Hot Gas At Highest Evaluated & Study Application Rate (430 lb methyl bromide/treated/acre) 

50 169.0 117.0 65.0 13.0 13.0 230 332 597 2987 2987 

75 559.0 429.0 351.0 195.0 117.0 69 91 111 199 332 

90 1027.0 871.0 741.0 559.0 429.0 38 45 52 69 91 

95 1365.0 1209.0 1079.0 845.0 663.0 28 32 36 46 59 

97 1573.0 1443.0 1287.0 1027.0 845.0 25 27 30 38 46 

99 1963.0 1833.0 1677.0 1339.0 1131.0 20 21 23 29 34 

99.9 2561.0 2431.0 2249.0 1859.0 1573.0 15 16 17 21 25 
Page 31 of 38 

6.0 Conclusions 

The recent emissions data have been reviewed from a technical perspective and each have been 

found to be acceptable for use in the risk assessment process. These data reflect emissions based on the use 

of measures such as EVOH-containing high barrier films, reactive adjuvants, and injection depths designed 

to reduce emissions. The studies were conducted in the central valley of California and on the eastern coast 

of Florida where a large percentage of actual methyl bromide use occurs.13 The analytical aspects of the 

study were acceptable and no correction for recovery was required. The Agency also calculated flux values 

for each field plot and found that the results were comparable to those calculated by the investigators. All 

flux estimates used in the risk assessment included in this document are based on the Agency-calculated 

flux estimates. 

The results indicate that overall emissions were reduced when the control measures were used 

compared to current common agricultural practices. PERFUM predicted buffer zones were essentially zero 

meters or very short compared to those predicted in the 2007 risk assessment in all cases accept in selected 

circumstances at the highest percentiles of exposure or for very large fields. Air concentration data from 

PERFUM were also considered and the risks calculated based on this information were also not of concern 

in circumstances that are similar to those observed for the buffer outputs of PERFUM as would be expected. 

As expected, the impermeable nature of the TIFs used in this research retained methyl bromide to the point 

where emission levels were raised as a result of tarp cutting operations in some circumstances to levels 

similar to after application. This phenomenon should be considered, in light of the associated risks, related 

to issues such as buffer zone duration and the duration of the entry restricted interval. 

[Note: The MBIP studies used as the basis for this assessment quantified chloropicrin emissions in addition 

to methyl bromide emissions since both fumigants were applied. The analysis of the chloropicrin data have 

been completed in a separate memo that includes not only the results of these studies but other pertinent 

chloropicrin emissions data.] 

 

13 The research plan indicated that the Florida location was supposed to be Plant City but Fort Pierce was used instead, it is also a 

substantial production area so it appears to be an acceptable modification of the research plan. 
Page 32 of 38 

Appendix A 

Summary of Unscaled Flux 

Values By Sampling Period 
Page 33 of 38 

Appendix A - Summary of Unscaled California Flux Values By Sampling Period 

Period No. Sample Interval Times Duration (Hrs.) Est. Flux 

(ug/m2-s) 

Field 1 - Shallow Broadcast Tarped (polyethylene) 

1 06/02/2009 09:00 - 13:00 4.0 222.95 

2 06/02/2009 13:00 - 19:00 6.0 210.93 

3 06/02/2009 19:00 - 01:00 6.0 37.86 

4 06/03/2009 01:00 - 07:00 6.0 58.35 

5 06/03/2009 07:00 - 13:00 6.0 27.89 

6 06/03/2009 13:00 - 19:00 6.0 28.17 

7 06/03/2009 19:00 - 01:00 6.0 23.50 

8 06/04/2009 01:00 - 07:00 6.0 11.44 

9 06/04/2009 07:00 - 19:00 12.0 14.36 

10 06/05/2009 19:00 - 07:00 12.0 7.24 

11 06/05/2009 07:00 - 19:00 12.0 5.08 

12 06/06/2009 19:00 - 07:00 12.0 3.06 

13 06/06/2009 07:00 - 19:00 12.0 3.68 

14 06/07/2009 19:00 - 07:00 12.0 1.74 

15 06/07/2009 07:00 - 19:00 12.0 3.45 

16 06/08/2009 19:00 - 07:00 12.0 1.80 

17 06/08/2009 07:00 - 13:00 6.0 8.63 

18 06/08/2009 13:00 - 19:00 6.0 8.55 

19 06/08/2009 19:00 - 01:00 6.0 6.26 

20 06/09/2009 01:00 - 07:00 6.0 2.62 

21 06/09/2009 07:00 - 19:00 12.0 0.79 

22 06/10/2009 19:00 - 07:00 12.0 1.25 

23 06/10/2009 07:00 - 19:00 12.0 0.99 

24 06/11/2009 19:00 - 07:00 12.0 1.05 

25 06/11/2009 07:00 - 19:00 12.0 0.65 

26 06/12/2009 19:00 - 07:00 12.0 0.88 

27 06/12/2009 07:00 - 19:00 12.0 0.62 

28 06/13/2009 19:00 - 07:00 12.0 0.87 

29 06/13/2009 07:00 - 19:00 12.0 0.52 

30 06/14/2009 19:00 - 07:00 12.0 0.58 

31 06/14/2009 07:00 - 19:00 12.0 0.02 

32 06/15/2009 19:00 - 07:00 12.0 0.34 

Field 2 - Shallow Broadcast Tarped (EVOH Resin Barrier Tarp) 

1 06/02/2009 09:00 - 13:00 4.0 70.24 

2 06/02/2009 13:00 - 19:00 6.0 98.22 

3 06/02/2009 19:00 - 01:00 6.0 3.72 

4 06/03/2009 01:00 - 07:00 6.0 4.82 

5 06/03/2009 07:00 - 13:00 6.0 2.23 

6 06/03/2009 13:00 - 19:00 6.0 56.79 

7 06/03/2009 19:00 - 01:00 6.0 0.85 

8 06/04/2009 01:00 - 07:00 6.0 0.44 

9 06/04/2009 07:00 - 19:00 12.0 15.47 

10 06/05/2009 19:00 - 07:00 12.0 0.83 

11 06/05/2009 07:00 - 19:00 12.0 4.07 

12 06/06/2009 19:00 - 07:00 12.0 0.55 
Page 34 of 38 

Appendix A - Summary of Unscaled California Flux Values By Sampling Period 

Period No. Sample Interval Times Duration (Hrs.) Est. Flux 

(ug/m2-s) 

13 06/06/2009 07:00 - 19:00 12.0 4.26 

14 06/07/2009 19:00 - 07:00 12.0 0.47 

15 06/07/2009 07:00 - 19:00 12.0 6.35 

16 06/08/2009 19:00 - 07:00 12.0 0.50 

17 06/08/2009 07:00 - 13:00 6.0 33.25 

18 06/08/2009 13:00 - 19:00 6.0 43.88 

19 06/08/2009 19:00 - 01:00 6.0 22.88 

20 06/09/2009 01:00 - 07:00 6.0 11.10 

21 06/09/2009 07:00 - 19:00 12.0 6.39 

22 06/10/2009 19:00 - 07:00 12.0 3.31 

23 06/10/2009 07:00 - 19:00 12.0 2.80 

24 06/11/2009 19:00 - 07:00 12.0 2.49 

25 06/11/2009 07:00 - 19:00 12.0 1.50 

26 06/12/2009 19:00 - 07:00 12.0 2.76 

27 06/12/2009 07:00 - 19:00 12.0 1.69 

28 06/13/2009 19:00 - 07:00 12.0 4.81 

29 06/13/2009 07:00 - 19:00 12.0 0.90 

30 06/14/2009 19:00 - 07:00 12.0 1.72 

31 06/14/2009 07:00 - 19:00 12.0 0.45 

32 06/15/2009 19:00 - 07:00 12.0 1.60 

Field 3 - Shallow Broadcast Tarped (EVOH Resin Barrier Tarp & KTS) 

1 06/02/2009 09:00 - 13:00 4.0 27.09 

2 06/02/2009 13:00 - 19:00 6.0 35.64 

3 06/02/2009 19:00 - 01:00 6.0 0.92 

4 06/03/2009 01:00 - 07:00 6.0 2.25 

5 06/03/2009 07:00 - 13:00 6.0 2.12 

6 06/03/2009 13:00 - 19:00 6.0 27.48 

7 06/03/2009 19:00 - 01:00 6.0 0.73 

8 06/04/2009 01:00 - 07:00 6.0 0.39 

9 06/04/2009 07:00 - 19:00 12.0 7.17 

10 06/05/2009 19:00 - 07:00 12.0 0.01 

11 06/05/2009 07:00 - 19:00 12.0 1.17 

12 06/06/2009 19:00 - 07:00 12.0 0.36 

13 06/06/2009 07:00 - 19:00 12.0 1.40 

14 06/07/2009 19:00 - 07:00 12.0 0.45 

15 06/07/2009 07:00 - 19:00 12.0 1.35 

16 06/08/2009 19:00 - 07:00 12.0 0.10 

17 06/08/2009 07:00 - 13:00 6.0 32.29 

18 06/08/2009 13:00 - 19:00 6.0 20.04 

19 06/08/2009 19:00 - 01:00 6.0 17.34 

20 06/09/2009 01:00 - 07:00 6.0 7.21 

21 06/09/2009 07:00 - 19:00 12.0 2.70 

22 06/10/2009 19:00 - 07:00 12.0 3.13 

23 06/10/2009 07:00 - 19:00 12.0 1.29 

24 06/11/2009 19:00 - 07:00 12.0 2.24 

25 06/11/2009 07:00 - 19:00 12.0 0.32 

26 06/12/2009 19:00 - 07:00 12.0 1.10 
Page 35 of 38 

Appendix A - Summary of Unscaled California Flux Values By Sampling Period 

Period No. Sample Interval Times Duration (Hrs.) Est. Flux 

(ug/m2-s) 

27 06/12/2009 07:00 - 19:00 12.0 0.01 

28 06/13/2009 19:00 - 07:00 12.0 0.92 

29 06/13/2009 07:00 - 19:00 12.0 0.02 

30 06/14/2009 19:00 - 07:00 12.0 1.18 

31 06/14/2009 07:00 - 19:00 12.0 0.47 

32 06/15/2009 19:00 - 07:00 12.0 0.76 

Field 4 - Deep Strip Tarped (EVOH Resin Barrier Tarp) 

1 06/02/2009 09:00 - 13:00 4.0 20.91 

2 06/02/2009 13:00 - 19:00 6.0 20.91 

3 06/02/2009 19:00 - 01:00 6.0 10.68 

4 06/03/2009 01:00 - 07:00 6.0 22.36 

5 06/03/2009 07:00 - 13:00 6.0 4.76 

6 06/03/2009 13:00 - 19:00 6.0 32.60 

7 06/03/2009 19:00 - 01:00 6.0 9.18 

8 06/04/2009 01:00 - 07:00 6.0 2.99 

9 06/04/2009 07:00 - 19:00 12.0 5.26 

10 06/05/2009 19:00 - 07:00 12.0 4.80 

11 06/05/2009 07:00 - 19:00 12.0 4.03 

12 06/06/2009 19:00 - 07:00 12.0 3.26 

13 06/06/2009 07:00 - 19:00 12.0 2.76 

14 06/07/2009 19:00 - 07:00 12.0 2.06 

15 06/07/2009 07:00 - 19:00 12.0 2.57 

16 06/08/2009 19:00 - 07:00 12.0 3.05 

17 06/08/2009 07:00 - 13:00 6.0 8.27 

18 06/08/2009 13:00 - 19:00 6.0 3.99 

19 06/08/2009 19:00 - 01:00 6.0 8.28 

20 06/09/2009 01:00 - 07:00 6.0 5.39 

21 06/09/2009 07:00 - 19:00 12.0 1.88 

22 06/10/2009 19:00 - 07:00 12.0 2.91 

23 06/10/2009 07:00 - 19:00 12.0 1.35 

24 06/11/2009 19:00 - 07:00 12.0 1.90 

25 06/11/2009 07:00 - 19:00 12.0 0.64 

26 06/12/2009 19:00 - 07:00 12.0 1.07 

27 06/12/2009 07:00 - 19:00 12.0 0.42 

28 06/13/2009 19:00 - 07:00 12.0 0.51 

29 06/13/2009 07:00 - 19:00 12.0 0.69 

30 06/14/2009 19:00 - 07:00 12.0 1.34 

31 06/14/2009 07:00 - 19:00 12.0 0.57 

32 06/15/2009 19:00 - 07:00 12.0 0.39 

Field 5 - Deep Broadcast Tarped (EVOH Resin Barrier Tarp) 

1 06/02/2009 09:00 - 13:00 4.0 19.29 

2 06/02/2009 13:00 - 19:00 6.0 19.29 

3 06/02/2009 19:00 - 01:00 6.0 13.37 

4 06/03/2009 01:00 - 07:00 6.0 3.80 

5 06/03/2009 07:00 - 13:00 6.0 1.17 

6 06/03/2009 13:00 - 19:00 6.0 13.48 

7 06/03/2009 19:00 - 01:00 6.0 2.45 
Page 36 of 38 

Appendix A - Summary of Unscaled California Flux Values By Sampling Period 

Period No. Sample Interval Times Duration (Hrs.) Est. Flux 

(ug/m2-s) 

8 06/04/2009 01:00 - 07:00 6.0 0.43 

9 06/04/2009 07:00 - 19:00 12.0 3.58 

10 06/05/2009 19:00 - 07:00 12.0 0.54 

11 06/05/2009 07:00 - 19:00 12.0 1.52 

12 06/06/2009 19:00 - 07:00 12.0 0.26 

13 06/06/2009 07:00 - 19:00 12.0 1.82 

14 06/07/2009 19:00 - 07:00 12.0 0.44 

15 06/07/2009 07:00 - 19:00 12.0 2.47 

16 06/08/2009 19:00 - 07:00 12.0 0.34 

17 06/08/2009 07:00 - 13:00 6.0 42.72 

18 06/08/2009 13:00 - 19:00 6.0 49.07 

19 06/08/2009 19:00 - 01:00 6.0 28.44 

20 06/09/2009 01:00 - 07:00 6.0 22.93 

21 06/09/2009 07:00 - 19:00 12.0 4.31 

22 06/10/2009 19:00 - 07:00 12.0 7.73 

23 06/10/2009 07:00 - 19:00 12.0 2.84 

24 06/11/2009 19:00 - 07:00 12.0 6.03 

25 06/11/2009 07:00 - 19:00 12.0 2.08 

26 06/12/2009 19:00 - 07:00 12.0 3.02 

27 06/12/2009 07:00 - 19:00 12.0 2.30 

28 06/13/2009 19:00 - 07:00 12.0 4.29 

29 06/13/2009 07:00 - 19:00 12.0 1.10 

30 06/14/2009 19:00 - 07:00 12.0 3.63 

31 06/14/2009 07:00 - 19:00 12.0 0.60 

32 06/15/2009 19:00 - 07:00 12.0 1.29 

 
Page 37 of 38 

Appendix A - Summary of Unscaled Florida Flux Values By Sampling Period 

Period No. Sample Interval Times Duration (Hrs.) Est. Flux 

(ug/m2-s) 

Field 1 - Tarped Raised Bed 

1 1/15/2010 9:45 - 13:00 3:15 0.06 

2 1/15/2010 13:00 - 19:00 6:00 19.79 

3 1/15/2010 19:00 - 01:00 6:00 10.42 

4 1/16/2010 01:00 - 07:00 6:00 6.47 

5 1/16/2010 07:00 - 13:00 6:00 8.82 

6 1/16/2010 13:00 - 19:00 6:00 16.34 

7 1/16/2010 19:00 - 01:00 6:00 6.34 

8 1/17/2010 01:00 - 07:00 6:00 15.68 

9 1/17/2010 07:00 - 19:00 12:00 1.88 

10 1/17/2010 19:00 - 07:00 12:00 0.11 

11 1/18/2010 07:00 - 19:00 12:00 1.18 

12 1/18/2010 19:00 - 07:00 12:00 0.26 

13 1/19/2010 07:00 - 19:00 12:00 0.80 

14 1/19/2010 19:00 - 07:00 12:00 0.65 

15 1/20/2010 07:00 - 19:00 12:00 0.99 

16 1/20/2010 19:00 - 07:00 12:00 0.24 

17 1/21/2010 07:00 - 19:00 12:00 0.46 

18 1/21/2010 19:00 - 07:00 12:00 0.94 

19 1/22/2010 07:00 - 19:00 12:00 1.00 

20 1/22/2010 19:00 - 07:00 12:00 1.02 

21 1/23/2010 07:00 - 19:00 12:00 0.94 

22 1/23/2010 19:00 - 07:00 12:00 1.04 

23 1/24/2010 07:00 - 20:00 13:00 0.36 

24 1/24/2010 20:00 - 07:45 11:45 0.95 

Field 2 - Hot Gas 

1 1/15/2010 1000 – 1345 3:45 104.99 

2 1/15/2010 1345 – 1845 5:00 15.38 

3 1/15/2010 1845 – 0130 6:45 150.29 

4 1/16/2010 0130 – 0700 5:30 19.79 

5 1/16/2010 0700 – 1245 5:45 5.38 

6 1/16/2010 1245 – 1845 6:00 0.62 

7 1/16/2010 1845 – 0045 6:00 0.57 

8 1/17/2010 0045 – 0645 6:00 12.56 

9 1/17/2010 0645 – 1845 12:00 1.46 

10 1/17/2010 1845 – 0700 12:15 0.56 

11 1/18/2010 0700 – 1845 11:45 14.52 

12 1/18/2010 1845 – 0700 12:15 0.54 

13 1/19/2010 0700 – 1900 12:00 41.32 

14 1/19/2010 1900 – 0700 12:00 0.10 

15 1/20/2010 0700 – 1845 11:45 13.60 

16 1/20/2010 1845 – 0700 12:15 0.11 

17 1/21/2010 0700 -1845 11:45 1.84 

18 1/21/2010 1845 – 0645 12:00 0.55 

19 1/22/2010 0645 – 1245 6:00 190.11 

20 1/22/2010 1245 – 1900 6:15 87.36 
Page 38 of 38 

Appendix A - Summary of Unscaled Florida Flux Values By Sampling Period 

Period No. Sample Interval Times Duration (Hrs.) Est. Flux 

(ug/m2-s) 

21 1/22/2010 1900 - 0030 5:30 26.06 

22 1/23/2010 0030 - 0700 6:30 21.35 

23 1/23/2010 0700 - 1900 12:00 6.78 

24 1/23/2010 1900 - 0700 12:00 0.90 

25 1/24/2010 0700 - 1845 11:45 0.44 

26 1/24/2010 1845 - 0645 12:00 0.51