# -

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C.. 20460

July 

### 6, 2010

PC Code: 043301 DP Barcode: 379499



### MEMORANDUM



### Subject:

To:

And: Verification of Furfural Air Estimated Exposure Concentrations

Kelly Orourke, Biologist Ray Kent, Branch Chief Health Effects Division (7509P) Office of Pesticide Programs

Cynthia Giles-Parker, Branch Chief Mary Waller, Review Manager Tamue Gibson, Risk Manager Reviewer Fungicide Branch Registration Division (7505P) Office of Pesticide Programs



### From:

Through: Gabe Rothman, Environmental Scientist Environmental Risk Branch 5 Environmental Fate and Effects Division (7507P) Office of Pesticide Programs

Mah Shamim, Chief, Environmental Risk Branch 5 Environmental Fate and Effects Division Office of Pesticide Programs

The Environmental Fate and Effects Division (EFED) has verified the Industrial Source Complex Short Tenn Model (ISCST3 version 02035, developed by the EPA Office of Air Quality Planning and Standards) maximum peak estimated exposure concentrations in the air submitted by the registrant in its justification to reduce the re-entry time interval restriction for gold course workers after furfural treatments. In general, EFED agrees that the modeling method that was utilized by the registrant is suitable for this purpose and results are conservative for the scenarios presented.

1

### 2 The ISCST3 modeling work (e.g., input files, ou tput files, and meteor ological files) was provided by Sullivan Environmental Consulti ng, Inc. Consistent with OPPTS air dispersion modeling techniques using the Pr obablistic Exposure and Risk Model for Fumigants (PERFUM), which processes ISCST3 output, ISCST3 was run over five years of meteorological data. The meteorological st ation chosen by the registrant was from Tallahassee, FL and which encompassed da ta between the years 2001 – 2006. ISCST3 estimated air exposure concentrations were output over a locus of points focused over many rings radially extending out from the tr eated field of sizes 0.16 acres and 0.5 acres which the registrant believes to be representa tive of golf course tee and green areas. The registrant executed modeling for each flux rate in the temporal flux profile that was measured at the Georgia furfural third treatm ent to turf plot field volatility study (MRID No. 47569101) which were equivalent with EF ED’s calculated flux rates. Estimated exposure concentrations were determined for each flux rate held at steady state over the five years. This provides a suitable statis tical sample of each flux rate over different meteorological conditions and its influence on air concentrations. For each flux rate, the maximum peak concentration wa s reported by the registrant a nd is shown in Tables 2 and 3 in the letter entitled, “Comment s to Docket No. EPA-HQ-OPP-2009-0722: Registrant’s Response to the Agency’s Recommendation for the Establishment of Restricted Entry Intervals for Golf Course Uses of Multiguard® Protect”, submitted by Toxcel on behalf of the registrant. The m odeling results provided by the registrant are conservative as compared to the PERFUM m odeling technique for the following reasons:

• 

### The registrant reported maximum peak estimated exposure air concentration values rather than concentrations at a specific significance level such as is often chosen by OPPTS for the basi s of regulatory decisions.

• 

### The time of day effect on flux rates is not taken into account in the registrant’s modeling. One flux rate at a time is cons idered and subject to five years of meteorological data rather than the varying flux rates over time which are subject to the five years of meteorology as pro cessed in PERFUM used for OPPTS risk

assessments.

• 

### The registrant reported estimated exposu re air concentrati on values at ground level rather than breathing height whic h is at approximately 1.5 meters above ground level. Estimated exposure air concen trations in PERFUM are reported at 1.5 meters above ground level. Given that furfural is being emitted as a ground release from a treated field, maximum peak air concentrations are expected to be highest closer to the ground.

EFED performed a verification of the regi strant’s modeling using the SCREEN3 air dispersion model (version 96043, also devel oped at the EPA Office of Air Quality Planning and Standards). As is the case in PERFUM, the SCREEN3 models plume dispersion dynamics equivalent to ISCST 3. However, rather than using a robust multiple-year meteorological dataset, SCREEN3 uses a combination of 54 wind speeds and turbulence stability classes and conser vatively identifies the worst-case case combination of meteorological data coupled w ith the assumption that the wind is blowing

### 3 directly from the pollution source towards th e receiving point of in terest in order to obtain the peak concentrations . Given the registrant’s presentation of maximum peak estimated exposure concentrati ons at points focused at ri ngs around a treated field, the SCREEN3 results should be similar or equiva lent to the registrant’s values. EFED modeling using the flux rates a nd conducted at ground-level consis tent with the registrant (not shown) resulted in sli ghtly higher values than the re gistrant estimated air exposure values.

As per the Health Effects Division’s reque st, EFED also conducted modeling using SCREEN3 independent of the registrant’s m odeling to adjust flux rates to reflect the maximum labeled application ra te and to account for the appr opriate breathing height of 1.5 meters above ground level. In addition, EF ED accounted for field sizes up to 1 acre. Hence, SCREEN3 modeling was conducted for 0.16 acres, 0.5 acres, and 1.0 acre treated fields. Table 1 below shows the input values for the SCREEN3 parameters.

Table 1. Input parameters into SCREEN3. Input Parameter Option/Value Source Type Area Emission Rates (g/m 2 

### s) Georgia Study Hours 0 - 1 1,3 

### – 382.32 x 10 -6 

### Georgia Study Hours 1 - 2 1,3 

### – 0.06 x 10 -6 

### California Study Hours 0 - 1 2,3 

### – 1,064.74 x 10 -6 

### California Study Hours 1 - 2 2,3 

### – 131.1 x 10 -6 

### California Study Hours 2 - 3 2,3 

### – 0.32 x 10 -6 

### Source Height (m) 0 Length of Large Sides of Source (m) 25.45, 44.00, 63.60

Length of Smaller Sides of Source (m) 25.45, 44.00, 63.60

Receptor Height (m) 1.5 Urban/Rural Option Rural

1. Flux profile extracted based on the third treatment to turf subplot (MRID No. 47569101). 2. Flux profile extracted based on the second tr eatment to turf subplot (MRID No. 47483901). 3. Flux values scaled from measured values at application rates from field volatility studi es to 69.4 lbs. a.i./acre. 1.



### Table 2 below shows the SCREEN3 maximum peak estimated exposure concentrations (EECs) in air possible over time after furfur al applications. In general, maximum peak EECs fall to small values for all field sizes after the first hour following the application based on flux rates developed from the Georgia study. The results using flux rates developed from the California second treatmen t to turf plot field volatility study (MRID No. 47483901), where higher flux rates were meas ured than the Georgia third treatment to turf plot field volatility study (MRID No. 47569101), suggests a similar trend after the second hour following the appli cation. EFED notes that ma ximum peak EECs over later time periods following the application than what is shown here will be even smaller as flux rates measured in all of the turf plots decrease to even lower levels over time.

### 4 Table 2. SCREEN3 maximum peak estimated exposure concentrations in air at times after application.

Study Basis/Modeled Field Size Hours PostApplication Flux Rate ( μ g/m 2 

### s) Maximum Peak EEC in Air ( μ g/m 3 

### ) Georgia – 0.16 Acres 0 - 1 382.32 1,3 

### 3,884.37 Georgia – 0.16 Acres 1 - 2 0.06 1,3 

### 0.61 Georgia – 0.5 Acres 0 - 1 382.32 1,3 

### 6,801.47 Georgia – 0.5 Acres 1 - 2 0.06 1,3 

### 1.07 Georgia – 1.0 Acre 0 - 1 382.32 1,3 

### 9,584.76 Georgia – 1.0 Acre 1 - 2 0.06 1,3 

### 1.50 California – 0.16 Acres 0 - 1 1,064.74 2,3 

### 10,817.76 California – 0.16Acres 1 - 2 131.1 2,3 

### 1,331.98 California – 0.16 Acres 2 - 3 0.32 2,3 

### 3.25 California – 0.5 Acres 0 - 1 1,064.74 2,3 

### 18,941.72 California – 0.5 Acres 1 - 2 131.1 2,3 

### 2,332.27 California – 0.5 Acres 2 - 3 0.32 2,3 

### 5.69 California – 1.0 Acre 0 - 1 1,064.74 2,3 

### 26,693.03 California – 1.0 Acre 1 - 2 131.1 2,3 

### 3,286.68 California – 1.0 Acre 2 - 3 0.32 2,3 

### 8.02

1. Flux profile extracted based on the third treatment to turf suplot (MRID No. 47569101). 2. Flux profile extracted based on the second tr eatment to turf subplot (MRID No. 47483901). 3. Flux values scaled from measured values at application rates from field volatility studi es to 69.4 lbs. a.i./acre.

### 5 Attachment 1 – SCREEN3 Modeling Output Files

### 6 **Figure 1-1. SCREEN3 modeling run normalized to 1 g/m 2**  **s flux rate for 0.16 acre field.** 

07/01/10

11:54:44 *** SCREEN3 MODEL RUN *** *** VERSION DATED 96043 ***

Furfural REI

SIMPLE TERRAIN INPUTS: SOURCE TYPE = AREA EMISSION RATE (G/(S-M**2)) = 1.00000 SOURCE HEIGHT (M) = .0000 LENGTH OF LARGER SIDE (M) = 25.4500 LENGTH OF SMALLER SIDE (M) = 25.4500 RECEPTOR HEIGHT (M) = 1.5000 URBAN/RURAL OPTION = RURAL THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.

MODEL ESTIMATES DIRECTION TO MAX CONCENTRATION

BUOY. FLUX = .000 M**4/S**3; MOM. FLUX = .000 M**4/S**2.

*** FULL METEOROLOGY ***

********************************** *** SCREEN AUTOMATED DISTANCES *** **********************************

*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***

DIST CONC U10M USTK MIX HT PLUME MAX DIR (M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) (DEG)

------- ---------- ---- ----- ----- ------ ------ ------- 1. .8613E+06 5 1.0 1.0 10000.0 .00 43. 100. .8246E+07 6 1.0 1.0 10000.0 .00 45.

MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 1. M: 58. .1016E+08 6 1.0 1.0 10000.0 .00 45.

*************************************** *** SUMMARY OF SCREEN MODEL RESULTS *** ***************************************

CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M**3) MAX (M) HT (M)

-------------- ----------- ------- ------- SIMPLE TERRAIN .1016E+08 58. 0.

***************************************************

### 7 **Figure 1-2. SCREEN3 modeling run normalized to 1 g/m 2**  **s flux rate for 0.5 acre field.** 

07/01/10

12:09:40 *** SCREEN3 MODEL RUN *** *** VERSION DATED 96043 ***

Furfural REI

SIMPLE TERRAIN INPUTS: SOURCE TYPE = AREA EMISSION RATE (G/(S-M**2)) = 1.00000 SOURCE HEIGHT (M) = .0000 LENGTH OF LARGER SIDE (M) = 44.0000 LENGTH OF SMALLER SIDE (M) = 44.0000 RECEPTOR HEIGHT (M) = 1.5000 URBAN/RURAL OPTION = RURAL THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.

MODEL ESTIMATES DIRECTION TO MAX CONCENTRATION

BUOY. FLUX = .000 M**4/S**3; MOM. FLUX = .000 M**4/S**2.

*** FULL METEOROLOGY ***

********************************** *** SCREEN AUTOMATED DISTANCES *** **********************************

*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***

DIST CONC U10M USTK MIX HT PLUME MAX DIR (M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) (DEG)

------- ---------- ---- ----- ----- ------ ------ ------- 1. .4288E+07 5 1.0 1.0 10000.0 .00 45. 100. .1562E+08 6 1.0 1.0 10000.0 .00 45.

MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 1. M: 67. .1779E+08 6 1.0 1.0 10000.0 .00 45.

*************************************** *** SUMMARY OF SCREEN MODEL RESULTS *** ***************************************

CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M**3) MAX (M) HT (M)

-------------- ----------- ------- ------- SIMPLE TERRAIN .1779E+08 67. 0.

### 8 **Figure 1-3. SCREEN3 modeling run normalized to 1 g/m 2**  **s flux rate for 1.0 acre field.** 

07/01/10

12:18:08 *** SCREEN3 MODEL RUN *** *** VERSION DATED 96043 ***

Furfural REI

SIMPLE TERRAIN INPUTS: SOURCE TYPE = AREA EMISSION RATE (G/(S-M**2)) = 1.00000 SOURCE HEIGHT (M) = .0000 LENGTH OF LARGER SIDE (M) = 63.6000 LENGTH OF SMALLER SIDE (M) = 63.6000 RECEPTOR HEIGHT (M) = 1.5000 URBAN/RURAL OPTION = RURAL THE REGULATORY (DEFAULT) MIXING HEIGHT OPTION WAS SELECTED. THE REGULATORY (DEFAULT) ANEMOMETER HEIGHT OF 10.0 METERS WAS ENTERED.

MODEL ESTIMATES DIRECTION TO MAX CONCENTRATION

BUOY. FLUX = .000 M**4/S**3; MOM. FLUX = .000 M**4/S**2.

*** FULL METEOROLOGY ***

********************************** *** SCREEN AUTOMATED DISTANCES *** **********************************

*** TERRAIN HEIGHT OF 0. M ABOVE STACK BASE USED FOR FOLLOWING DISTANCES ***

DIST CONC U10M USTK MIX HT PLUME MAX DIR (M) (UG/M**3) STAB (M/S) (M/S) (M) HT (M) (DEG)

------- ---------- ---- ----- ----- ------ ------ ------- 1. .8519E+07 5 1.0 1.0 10000.0 .00 45. 100. .2341E+08 6 1.0 1.0 10000.0 .00 45.

MAXIMUM 1-HR CONCENTRATION AT OR BEYOND 1. M: 77. .2507E+08 6 1.0 1.0 10000.0 .00 45.

*************************************** *** SUMMARY OF SCREEN MODEL RESULTS *** ***************************************

CALCULATION MAX CONC DIST TO TERRAIN PROCEDURE (UG/M**3) MAX (M) HT (M)

-------------- ----------- ------- ------- SIMPLE TERRAIN .2507E+08 77. 0.

***************************************************