UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

MEMORANDUM 

Date: 15-SEP-2015 

SUBJECT: Profenofos: Review of "Worker Reentry Exposure to Profenofos in Cotton 

Treated with Curacron® 8E" 

PC Code: 111401 

Decision Number: 482022 

Petition Number: NA 

Risk Assessment Type: NA 

TXR Number: NA 

MRID Numbers: 42851302 

DP Barcode: 0429108 

Registration Number: NIA 

Regulatory Action: NIA 

Case Number: 2540 

CAS Number: 41198-08-7 

40CFR: §180.404 

FROM: 

Risk 

Kelly 

Assessment 

Lowe, Environmental 

Branch I (RAB 

Scientist 1) ~~ 

THROUGH: 

TO: 

Health Effects Division (HED), 7509P 

Thurston Morton, Acting Branch Chief 

RABI I HED, 7509P 

Christina Scheltema 

Patricia Parrott 

Pesticide Re-Evaluation Division (PRD) (7508P) 

ACTION REQUESTED: 

,/ 

-

The Registration Division (RD) requested that the Health Effects Division (HED) conduct a 

review of the submitted worker reentry exposure study (with concurrent dislodgeable foliar 

residue data) for profenofos. 

SUMMARY OF STUDY RESULTS: 

The study was conducted during the 1992 growing season at three test sites located in NAFTA 

Region 2. Test sites 1, 2, and 3 were located in Cheraw, SC, McFarlan, NC, and Chesterfield, 

SC, respectively. The sites were approximately 2 to 8 miles from each other. Geographical and 

climatic conditions were relevant to the use pattern proposed. The trial sites consisted of one 

control plot and one treatment plot, with the treatment plot receiving six foliar broadcast 

applications of profenofos, formulated as an emulsifiable concentrate (EC) containing 73% of 

the active ingredient (ai) profenofos. Applications were made to cotton via tractor-mounted 

Page 1 of 95
Page 2 of 56 

groundboom sprayers at a target rate of 1 lb ai/A/application. The applications were made at 5-8 

day re-treatment intervals using a spray volume of 15-17 gallons of water per acre (GPA). 

DFR: Duplicate control plot and treated plot DFR samples were collected using a Birkestrand 

leaf punch sampler prior to and after the first application, after the second application, prior to 

and after the third application, after the fourth and fifth applications, prior to and after the sixth 

(last) application, and at the following intervals after the last application: 1, 2, 3, 7, 14, 21, 28 

and 35 days. 

EPA calculated DFRs in μg/cm2

 (based on a 250 cm2 leaf surface area) with correction for the 

average low and high field fortification recoveries of each site separately. In general, DFRs at all 

sites declined rapidly within the first week after the last application, and then remained at low 

levels through the end of the sampling period. Residues did not decline to <LOQ (0.003 μg/cm2) 

by 35DAT6. The average DFR (and percent of application rate) at Site 1 (Cheraw, SC) was the 

highest at the 0DAT5 interval (2.83 μg/cm2; 26.5%). After the last application, the average DFR 

was a maximum of 1.74 μg/cm2

 (16.3%) at 0DAT6, declined to 0.40 μg/cm2 (3.8%) at 1DAT6, 

and continued to decline to 0.0047 μg/cm2 (0.04%) at 35DAT6. The average DFR (and percent 

of application rate) at Site 2 (McFarlan, NC) was the highest at the 0DAT2 interval (3.99 

μg/cm2; 29.7%). After the last application, the average DFR was a maximum of 1.82 μg/cm2

(17.1%) at 0DAT6, declined to 0.251 μg/cm2 (2.4%) at 1DAT6, and continued to decline to 

0.0046 μg/cm2

 (0.04%) at 35DAT6. The average DFR (and percent of application rate) at Site 3 

(Chesterfield, SC) was the highest at the 0DAT5 interval (5.19 μg/cm2; 44.5%). After the last 

application, the average DFR was a maximum of 2.48 μg/cm2

 (23.3%) at 0DAT6, declined to 

1.54 μg/cm2 (14.4%) at 1DAT6, and continued to decline to 0.0056 μg/cm2 (0.05%) at 35DAT6. 

Actual DFRs on 0DAT6 were 7 to 12 times higher than the predicted DFRs on 0DAT6. 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos, using the natural log of average DFR values. Using the 0DAT6 to 35DAT6 data, the 

Registrant calculated half-lives of 5 days (r = -0.85) for Site 1 (Cheraw, SC), 4.9 days (r = -0.77) 

for Site 2 (McFarlan, NC), and 4.6 days (r = -0.79) for Site 3 (Chesterfield, SC). The Registrant 

also performed regressions using the 0DAT6 through 7DAT6 data only, which assumes a 

biphasic curve. The Registrant calculated half-lives of 1.2 days (r = -0.91) for Site 1 (Cheraw, 

SC), 1.1 days (r = -0.80) for Site 2 (McFarlan, NC), and 0.86 days (r = -0.95) for Site 3 

(Chesterfield, SC). 

EPA first assumed first-order dissipation kinetics and conducted linear regression analysis using 

the natural logarithm of the average DFR values from 0DAT6 to 35DAT6. EPA's estimated halflife values were 5.1 days (R2

= 0.7132) for Site 1, 5.7 days (R2= 0.6351) for Site 2, and 4.7 days 

(R2

= 0.6271) for Site 3. However, the regression analysis did not appear visually to be a good fit 

for the data, and the actual DFRs on 0DAT6 were 7 to 12 times higher than the predicted DFRs 

on 0DAT6. Therefore, EPA did additional analysis and conducted a biphasic (“hockey stick”) 

regression analysis using Excel’s Solver, and the corrected average DFRs from immediately after 

the last application through the last sampling interval. This regression analysis appears (visually) 

to be a better fit of the data, and provides predicted Day 0 values of 2.3 μg/cm2

, 3.0 μg/cm2, and 

2.7 μg/cm2

, for Site 1 (Cheraw, SC), Site 2 (Chesterfield, SC), and Site 3 (McFarlan, NC), 

respectively. 

Page 2 of 95 Page 2 of 95
Page 3 of 56 

Worker Reentry Exposure (Dermal and Inhalation): At each of the three sites, five re-entry 

workers were monitored during post-application activities on the day of the last application 

(0DAT6) and the day after the last application (1DAT6). Three of the workers were scouters and 

two of workers were hoers. The work period was approximately 4 hours in duration. 

Dermal exposures were monitored using whole-body inner dosimeters, whole-body outer 

dosimeters, hand washes, and face/neck wipes. Inhalation exposures were monitored using air 

sorbent tubes and pre-loaded filter cassettes attached to air sampling pumps at an air flow rate of 

1 L/min. All workers wore 100% cotton, long underwear (inner dosimeter) over their choice of 

undergarments. Additionally, all workers were outer long sleeve and long pant garments (outer 

dosimeter) over the inner dosimeters. All workers also wore a baseball cap, and scouters only 

wore a pouch around the waist to collect cotton bolls. No additional personal protective 

equipment (PPE) was worn during monitoring activities (i.e., gloves, goggles, face masks, or 

respirators). 

Field fortification samples were prepared for each matrix at each sampling interval at one or two 

fortification levels. Average field fortification recoveries were generally acceptable (i.e., 70-

120%) with a few exceptions. Most notably, average recoveries were 37-65% for the inner 

whole body dosimeter at the low fortification level. 

Dermal exposures: EPA calculated both total dermal exposure and potential dermal exposure 

and presented the results in terms of transfer coefficients (μg/cm2

). The average DFRs used for 

0DAT6 and 1DAT6 intervals were 1.74 and 0.403 μg/cm2 at Site 1 (Cheraw, SC), 1.82 and 0.251 

μg/cm2 at Site 2 (McFarlan, NC), and 2.48 and 1.54 μg/cm2 at Site 3 (Chesterfield, SC). For 

scouters, average transfer coefficients for total dermal exposure were 176, 123, and 237 cm2

/hr 

on 0DAT6 for Sites 1, 2, and 3, respectively, and 330, 318, and 293 cm2/hr on 1DAT6 for Sites 

1, 2, and 3, respectively. For hoers, average transfer coefficients for total dermal exposure were 

86.9, 96.9, and 200 cm2/hr on 0DAT6 for Sites 1, 2, and 3, respectively, and 192, 198, and 122 

cm2

/hr on 1DAT6 for Sites 1, 2, and 3, respectively. 

Based on average values of transfer coefficients for total dermal exposure, body parts with 

significant residues (i.e., >10%) were the arm, leg and hand. For scouters and hoers on 0DAT6, 

the average distribution was approximately 30% each to the legs, arms, and hands. A similar 

distribution was observed for hoers on 1DAT6 (legs, arms and hands each receiving an average 

of 24-33%). For scouter on 1DAT6, the majority of the distribution was on the legs (average of 

59%), with 23% on the arms, and only 8.1% on the hands. Average penetration from the outer to 

inner dosimeters was highest for the arms (29 to 40%). Average penetration for the other regions 

ranged from 3.8 to 9.3%. 

Inhalation exposures: For scouters, average inhalation exposure was 5.48, 4.26, and 5.82 μg/hr 

on 0DAT6 for Sites 1, 2, and 3, respectively, and 2.05, 1.52, and 0.95 μg/hr on 1DAT6 for Sites 

1, 2, and 3, respectively. For hoers, average inhalation exposure was 7.47, 6.24, and 7.83 μg/hr 

on 0DAT6 for Sites 1, 2, and 3, respectively, and 2.86, 2.21, and 2.28 μg/hr on 1DAT6 for Sites 

1, 2, and 3, respectively. 

Page 3 of 95 Page 3 of 95
Page 4 of 56 

Cotton Boll residues: Duplicate cotton boll samples were collected at two sampling intervals at 

each site. Cotton bolls with carpels were collected at 35DAT6 to 38DAT6 and cotton bolls 

without carpels were collected on 44DAT6 to 70DAT6. Residues were <LOQ in all cotton boll 

only samples collected at 44-70DAT6. In the boll+carpel samples collected at 35-38DAT6, the 

average profenofos values were 0.0015 to 0.0025 μg/cm2

. 

CONCLUSIONS:

No major issues were identified during review of this study and the results are considered 

acceptable for risk assessment purposes. The DFR data can be used to estimate post-application 

worker exposure from the use of profenofos on agricultural crops. The worker reentry exposure 

data are not recommended to be used independently as chemical-specific data for risk assessment 

purposes. These data have already been incorporated into EPA’s Science Advisory Council for 

Exposure (ExpoSAC) Policy 3 (http://www.epa.gov/pesticides/science/exposac-policy-3-

march2013.pdf). The recommended transfer coefficients from this policy are recommended for 

use in the profenofos risk assessment in conjunction with the available chemical-specific DFR 

data. 

There were some concerns noted with respect to the DFR study. However, these are not 

anticipated to impact the validity of the data or its use in risk assessment. These concerns 

included: (1) only duplicate DFR samples were collected at each interval; the guidelines 

recommend the collection of triplicate DFR samples; (2) two field fortification levels were used 

(200 μg and 20,000 μg), as recommended in the EPA guidelines; however, the high fortification 

level was significantly higher than the treated samples; and (3) the EPA guidelines recommend a 

sample surface are of 400 cm2; however, in this study, the total leaf surface was only 250 cm2, as 

reported in the main text of the study. It should also be noted that the study actually used a 

surface area of 227 cm2 to calculate DFRs, based on a punch diameter of 1.7 cm. The Rabbit 

Tool website (the manufacturer of Birkestrand punches) states that the 2.5 cm2 punch has a 

diameter of 1.784 cm2

, thus it appears that the surface area of 227 cm2 is incorrect. 

Summary of DFR Values and Regression Analysis Results for Treated Cotton with Profenofos (MRID# 

42851302). 

Site Cheraw, SC Chesterfield, 

SC 

McFarland, 

NC 

Study Target Rate (lb ai/A) 1 lb ai/acre 

Spray Volume (GPA) 15-17 

Measured Average Day 0 Residue (μg/cm2) 0DAT6: 1.74 0DAT6: 2.48 0DAT6: 1.82 

Linear Regression Predicted Day 0 Residue (μg/cm2) 0DAT6: 0.234 0DAT6: 0.296 0DAT6: 0.146 

Slope -0.135 -0.149 -0.121 

Half-life (days) 5.1 4.7 5.7 

R2 0.7132 0.6271 0.6351 

Biphasic Regression Predicted Day 0 Residue (ug/cm2) 0DAT6: 2.3 0DAT6: 3.0 0DAT6: 2.7 

Slope -1.587, -1.587 -0.912, -1.588 -2.345, -1.588 

Page 4 of 95 Page 4 of 95
Page 5 of 56 

0.000

0.500

1.000

1.500

2.000

2.500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851302 - Cheraw, SC_profenofos

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851302_profenofos_Chesterfield, SC

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 5 of 95 Page 5 of 95
Page 6 of 56 

0.000

0.500

1.000

1.500

2.000

2.500

3.000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851302_profenofos_McFarlan, NC

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 6 of 95 Page 6 of 95
Page 7 of 56 

DATA EVALUATION RECORD

STUDY TYPE: Determination of Dislodgeable Foliar Residue in Cotton Treated with 

Profenofos; 875.2100 and Agricultural Post-application Exposure Study 

(Dermal and Inhalation); 875.2400, and 875.2500 

PC CODE: 111401

 

TEST MATERIAL Curacron® 8E, an emulsifiable concentrate (EC) formulation containing a 

nominal 73% of active ingredient (ai) profenofos (8 lb ai/gal) 

SYNONYMS: Common name: Profenofos 

Formulation Trade name: Curacron® 8E 

Chemical name: 0-(4-bromo-2-chlorphenyl) 0-ethyl S-propyl 

phosphorothioate 

CAS No.: 41198-08-7 

CITATIONS: Study Authors: Richard C. Honeycutt 

 Stephen Mabon 

 Title: Worker Reentry Exposure to Profenofos in 

Cotton Treated with Curacron® 8E 

 Report Date: May 21, 1993 

 Field Laboratory: H.E.R.A.C., Inc. 

 3704-B Boren Drive 

 Greensboro, NC 27407 

 Analytical Laboratory: EN-CAS Analytical Laboratories, Inc. 

2359 Farrington Point Dr. 

Winston-Salem, NC 27107 

 Identifying Codes: H.E.R.A.C. Study No. 92-205HE; H.E.R.A.C. 

Report No. 93-302; EN-CAS Study No. 92-

0064 

SPONSOR: CIBA-GEIGY Corporation (currently Syngenta Crop Protection) 

 Greensboro, NC 27419 

EXECUTIVE SUMMARY: 

Concurrent dislodgeable foliar residue (DFR) and agricultural post-application exposure studies 

were conducted with the purpose of: 

1) Determining the dissipation of DFR of the active ingredient profenofos applied to cotton; 

2) Estimating potential dermal and inhalation exposure to agricultural workers performing 

scouting and hoeing activities after application of profenofos to cotton; and 

3) Calculating transfer coefficients (cm2

/hr) for scouting and hoeing cotton using the DFR 

and dermal exposure data. 

Page 7 of 95 Page 7 of 95
Page 8 of 56 

The study was conducted during the 1992 growing season at three test sites located in NAFTA 

Region 2. Test sites 1, 2, and 3 were located in Cheraw, SC, McFarlan, NC, and Chesterfield, 

SC, respectively. The sites were approximately 2 to 8 miles from each other. Geographical and 

climatic conditions were relevant to the use pattern proposed. The trial sites consisted of one 

control plot and one treatment plot, with the treatment plot receiving six foliar broadcast 

applications of profenofos, formulated as an emulsifiable concentrate (EC) containing 73% of 

the active ingredient (ai) profenofos. Applications were made to cotton via tractor-mounted 

groundboom sprayers at a target rate of 1 lb ai/A/application. The applications were made at 5-8 

day re-treatment intervals using a spray volume of 15-17 gallons of water per acre (GPA). 

DFR: Duplicate control plot and treated plot DFR samples were collected using a Birkestrand 

leaf punch sampler prior to and after the first application, after the second application, prior to 

and after the third application, after the fourth and fifth applications, prior to and after the sixth 

(last) application, and at the following intervals after the last application: 1, 2, 3, 7, 14, 21, 28 

and 35 days. 

Residues were dislodged from the leaf punch samples immediately after collection using 0.004% 

dioctyl sodium sulfosuccinate (DSS) (Aerosol OT brand) solution. The samples were stored 

frozen prior to extraction for analysis by gas chromatography with flame photometric detection 

(GC-FPD). Concurrent recoveries were within the acceptable range of 70 to 120%. The 

reported limit of quantitation (LOQ) was 0.005 μg/mL (0.003 μg/cm2

); the limit of detection 

(LOD) was not reported. Field fortification samples were prepared in duplicate at two 

fortification levels at three sampling intervals. Average field fortification recoveries were 

acceptable (i.e., within 70-120%). 

The Registrant provided DFRs in μg/sample with correction for laboratory recovery (uncorrected 

results were not provided) and in μg/cm2

 (based on a 227 cm2 leaf surface area) with and without 

an additional correction for the overall average field fortification recovery from all sites 

combined. EPA calculated DFRs in μg/cm2 (based on a 250 cm2 leaf surface area) with 

correction for the average low and high field fortification recoveries of each site separately. 

In general, DFRs at all sites declined rapidly within the first week after the last application, and 

then remained at low levels through the end of the sampling period. Residues did not decline to 

<LOQ (0.003 μg/cm2

) by 35DAT6. 

The average DFR (and percent of application rate) at Site 1 (Cheraw, SC) was the highest at the 

0DAT5 interval (2.83 μg/cm2

; 26.5%). After the last application, the average DFR was a 

maximum of 1.74 μg/cm2

 (16.3%) at 0DAT6, declined to 0.40 μg/cm2 (3.8%) at 1DAT6, and 

continued to decline to 0.0047 μg/cm2 (0.04%) at 35DAT6. 

The average DFR (and percent of application rate) at Site 2 (McFarlan, NC) was the highest at 

the 0DAT2 interval (3.99 μg/cm2

; 29.7%). After the last application, the average DFR was a 

maximum of 1.82 μg/cm2

 (17.1%) at 0DAT6, declined to 0.251 μg/cm2 (2.4%) at 1DAT6, and 

continued to decline to 0.0046 μg/cm2

 (0.04%) at 35DAT6. 

Page 8 of 95 Page 8 of 95
Page 9 of 56 

The average DFR (and percent of application rate) at Site 3 (Chesterfield, SC) was the highest at 

the 0DAT5 interval (5.19 μg/cm2; 44.5%). After the last application, the average DFR was a 

maximum of 2.48 μg/cm2 (23.3%) at 0DAT6, declined to 1.54 μg/cm2 (14.4%) at 1DAT6, and 

continued to decline to 0.0056 μg/cm2

 (0.05%) at 35DAT6. Actual DFRs on 0DAT6 were 7 to 

12 times higher than the predicted DFRs on 0DAT6. 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos, using the natural log of average DFR values. Using the 0DAT6 to 35DAT6 data, the 

Registrant calculated half-lives of 5 days (r = -0.85) for Site 1 (Cheraw, SC), 4.9 days (r = -0.77) 

for Site 2 (McFarlan, NC), and 4.6 days (r = -0.79) for Site 3 (Chesterfield, SC). The Registrant 

also performed regressions using the 0DAT6 through 7DAT6 data only, which assumes a 

biphasic curve. The Registrant calculated half-lives of 1.2 days (r = -0.91) for Site 1 (Cheraw, 

SC), 1.1 days (r = -0.80) for Site 2 (McFarlan, NC), and 0.86 days (r = -0.95) for Site 3 

(Chesterfield, SC). 

EPA first assumed first-order dissipation kinetics and conducted linear regression analysis using 

the natural logarithm of the average DFR values from 0DAT6 to 35DAT6. EPA's estimated halflife values were 5.1 days (R2

= 0.7132) for Site 1, 5.7 days (R2= 0.6351) for Site 2, and 4.7 days 

(R2= 0.6271) for Site 3. However, the regression analysis did not appear visually to be a good fit 

for the data, and the actual DFRs on 0DAT6 were 7 to 12 times higher than the predicted DFRs 

on 0DAT6. Therefore, EPA did additional analysis and conducted a biphasic (“hockey stick”) 

regression analysis using Excel’s Solver, and the corrected average DFRs from immediately after 

the last application through the last sampling interval. This regression analysis appears (visually) 

to be a better fit of the data, and provides predicted Day 0 values of 2.3 μg/cm2, 3.0 μg/cm2, and 

2.7 μg/cm2, for Site 1 (Cheraw, SC), Site 2 (Chesterfield, SC), and Site 3 (McFarlan, NC), 

respectively. 

Worker Reentry Exposure (Dermal and Inhalation): At each of the three sites, five re-entry 

workers were monitored during post-application activities on the day of the last application 

(0DAT6) and the day after the last application (1DAT6). Three of the workers were scouters and 

two of workers were hoers. The work period was approximately 4 hours in duration. 

Dermal exposures were monitored using whole-body inner dosimeters, whole-body outer 

dosimeters, hand washes, and face/neck wipes. Inhalation exposures were monitored using air 

sorbent tubes and pre-loaded filter cassettes attached to air sampling pumps at an air flow rate of 

1 L/min. All workers wore 100% cotton, long underwear (inner dosimeter) over their choice of 

undergarments. Additionally, all workers were outer long sleeve and long pant garments (outer 

dosimeter) over the inner dosimeters. All workers also wore a baseball cap, and scouters only 

wore a pouch around the waist to collect cotton bolls. No additional personal protective 

equipment (PPE) was worn during monitoring activities (i.e., gloves, goggles, face masks, or 

respirators). The samples were stored frozen prior to extraction for analysis by GC-FPD. 

Concurrent recoveries were generally within the acceptable range of 70 to 120%. The reported 

LOQ was 1 μg/sample for inner and outer dosimeters, 0.00015 μg/mL for handwashes, 0.05 

μg/sample for face/neck wipes, and 0.1 μg/sample for air sorbent tubes and pre-loaded filter 

cassesstes; the LOD was not reported. 

Page 9 of 95 Page 9 of 95
Page 10 of 56 

Field fortification samples were prepared for each matrix at each sampling interval at one or two 

fortification levels. Average field fortification recoveries were generally acceptable (i.e., 70-

120%) with a few exceptions. Most notably, average recoveries were 37-65% for the inner 

whole body dosimeter at the low fortification level. 

Dermal exposures: Profenofos values for dermal matrix samples were presented in the study in 

units of μg/sample, with correction for concurrent laboratory recovery (if <100%) and for the 

overall average field fortification recovery for each matrix. Using the reported μg/sample values 

(already corrected for concurrent laboratory recovery), EPA calculated dermal exposures for 

each matrix in μg/sample and μg/hour, with correction for site specific average field fortification 

values from each recovery level. For all replicates, EPA used the nominal work duration of 4 

hours. For values <LOQ, EPA used a value of 1⁄2 LOQ in calculations. EPA also made 

adjustments, as necessary, to account for method extraction inefficiencies of handwash and 

face/neck wipes, and also extrapolated the face/neck wipe residue to the rest of the head which 

was not sampled. It should be noted that one scouter on 1DAT6 dropped out early because of 

heat exhaustion and was replaced with a new worker. EPA did not include the replicate which 

dropped out in summary calculations. 

EPA calculated both total dermal exposure and potential dermal exposure and presented the 

results in terms of transfer coefficients (μg/cm2

). Total dermal exposure is the sum of the inner 

dosimeter, total head, and hand exposures, and represents a worker wearing a single layer of 

clothing (long pants and long shirt) and no PPE (i.e. gloves, goggles, face masks, or respirators). 

Potential dermal exposure is the sum of the inner dosimeter, outer dosimeter, total head, and 

hand exposures and represents a worker wearing no clothing or PPE. Transfer coefficients are 

dermal exposure (μg/hr) divided by the average DFR (μg/cm2) on the reentry day. The average 

DFRs used for 0DAT6 and 1DAT6 intervals were 1.74 and 0.403 μg/cm2 at Site 1 (Cheraw, SC), 

1.82 and 0.251 μg/cm2 at Site 2 (McFarlan, NC), and 2.48 and 1.54 μg/cm2 at Site 3 

(Chesterfield, SC). 

For scouters, average transfer coefficients for total dermal exposure were 176, 123, and 237 

cm2

/hr on 0DAT6 for Sites 1, 2, and 3, respectively, and 330, 318, and 293 cm2/hr on 1DAT6 for 

Sites 1, 2, and 3, respectively. For hoers, average transfer coefficients for total dermal exposure 

were 86.9, 96.9, and 200 cm2

/hr on 0DAT6 for Sites 1, 2, and 3, respectively, and 192, 198, and 

122 cm2

/hr on 1DAT6 for Sites 1, 2, and 3, respectively. 

Based on average values of transfer coefficients for total dermal exposure, body parts with 

significant residues (i.e., >10%) were the arm, leg and hand. For scouters and hoers on 0DAT6, 

the average distribution was approximately 30% each to the legs, arms, and hands. A similar 

distribution was observed for hoers on 1DAT6 (legs, arms and hands each receiving an average 

of 24-33%). For scouter on 1DAT6, the majority of the distribution was on the legs (average of 

59%), with 23% on the arms, and only 8.1% on the hands. 

Average penetration from the outer to inner dosimeters was highest for the arms (29 to 40%). 

Average penetration for the other regions ranged from 3.8 to 9.3%. 

Inhalation exposures: Profenofos values for inhalation samples were presented in the study in 

Page 10 of 95 Page 10 of 95
Page 11 of 56 

units of μg/sample, with correction for concurrent laboratory recovery (if <100%) and for an 

overall average field fortification recovery of all sites combined. Air sorbent tube samples did 

not require correction because all residues were <LOQ. Using the reported μg/sample values 

(already corrected for concurrent laboratory recovery), EPA calculated air concentrations in 

μg/m3

 and inhalation exposures in μg/hr, with correction for site specific average field 

fortification values from each recovery level. For values <LOQ, EPA used a value of 1⁄2 LOQ in 

calculations. EPA summed the pre-loaded-filter cassette and air sorbent tube residues to provide 

total profenofos residues. The airborne concentration of profenofos was then calculated by 

dividing the corrected total residue value by the total volume of air drawn by the personal 

sampler over the sampling duration. The air concentrations were then adjusted for the NAFTA 

recommended inhalation rate of 1.0 m3/hr (light activity) for scouters and 1.6 m3/hr (moderate 

activity) for hoers to calculate the inhalation exposure values. 

For scouters, average inhalation exposure was 5.48, 4.26, and 5.82 μg/hr on 0DAT6 for Sites 1, 

2, and 3, respectively, and 2.05, 1.52, and 0.95 μg/hr on 1DAT6 for Sites 1, 2, and 3, 

respectively. For hoers, average inhalation exposure was 7.47, 6.24, and 7.83 μg/hr on 0DAT6 

for Sites 1, 2, and 3, respectively, and 2.86, 2.21, and 2.28 μg/hr on 1DAT6 for Sites 1, 2, and 3, 

respectively. 

Cotton Boll residues: Duplicate cotton boll samples were collected at two sampling intervals at 

each site. Cotton bolls with carpels were collected at 35DAT6 to 38DAT6 and cotton bolls 

without carpels were collected on 44DAT6 to 70DAT6. The samples were dislodged with using 

0.004% Aerosol OT solution. The samples were stored frozen prior to extraction for analysis by 

GC-FPD. Concurrent recoveries were within the acceptable range of 70 to 120%. The reported 

LOQ was 0.005 μg/mL (0.003 μg/cm2

); the LOD was not reported. Field fortification samples 

were prepared in duplicate at two fortification levels at three sampling intervals. Average field 

fortification recoveries were generally acceptable (i.e., within 70-120%). 

Profenofos values for cotton boll samples (with and without carpel) were presented in the study 

in units of μg/sample and in μg/cm2

 with correction for concurrent laboratory recovery (if 

<100%). No field fortification recovery correction was applied. Using the reported μg/sample 

values (already corrected for concurrent laboratory recovery), EPA calculated values in μg/cm2

with correction for site specific average field fortification values from each recovery level. 

Residues were <LOQ in all cotton boll only samples collected at 44-70DAT6. In the boll+carpel 

samples collected at 35-38DAT6, the average profenofos values were 0.0015 to 0.0025 μg/cm2

. 

The following concerns are noted with respect to the worker exposure study (Series 875.2400 

and 875.2500 Guidelines): 

 Fifteen workers were monitored at each interval; however, these were divided between 

all three sites and both worker types. On a per site basis, only three scouters and two 

hoers were monitored at each interval. 

 The exact monitoring time for each worker replicate was not provided. It was assumed 

for all calculations that each worker was monitored for the nominal 4 hour work duration. 

 The following issues with field fortification are noted: 

o Single field fortification levels were used for handwash, face/neck wipe, air filter, 

Page 11 of 95 Page 11 of 95
Page 12 of 56 

and air sorbent tube samples. 

o The average low level field fortification recoveries for the inner whole body 

dosimeters were 37.0-64.9%. No explanation for the extremely low recoveries 

was provided. 

o The fortification levels were not within range or did not bracket the field residues 

for the following matrices: 

 For face/neck wipes, the fortification level (200 μg) was at least an order 

of magnitude higher than the residue levels detected in the post-exposure 

treated samples (0.446 to 25.8 μg). 

 For inner dosimeters, the low fortification level (200 μg) was within the 

range of the treated samples (1.53 to 1,439 μg), but the high fortification 

level (20,000 μg) was an order of magnitude higher than the residue 

levels. 

 For air filters, the fortification level (25 μg) was higher than the residue 

levels detected in the treated samples (0.083 to 1.61 μg). 

 Profenofos residues were detected in handwash and face/neck wipe sample collected 

prior to the exposure event. No explanation was provided for the presence of these 

residues. The study subtracted these residues out from the post-exposure samples. 

 Profenofos residues were detected in dermal and inhalation field blank residues (up to 

34xLOQ). The study states that residues were probably detected due to the proximity of 

the sample preparation area to the field being sprayed. 

 For the face/neck wipe samples at Site 1 (Cheraw, SC) and 2 on 1DAT6, it appears that 

the study did not assign the correct worker activity to some of the samples. EPA used the 

worker activity assigned to the replicate for the other matrices. 

The following concerns were noted with respect to the DFR study (Series 875.2100 Guidelines): 

 Only duplicate DFR samples were collected at each interval. The guidelines recommend 

the collection of triplicate DFR samples. 

 Two field fortification levels were used (200 μg and 20,000 μg), as recommended in the 

EPA guidelines. The low fortification level was within range of the treated samples (0.80 

to 1,434 μg), but the high fortification level was significantly higher than the treated 

samples. 

 The EPA guidelines recommend a sample surface are of 400 cm2

. In this study the total 

leaf surface was only 250 cm2

, as reported in the main text of the study. It should also be 

noted that the study actually used a surface area of 227 cm2 to calculate DFRs, based on a 

punch diameter of 1.7 cm. The Rabbit Tool website (the manufacturer of Birkestrand 

punches) states that the 2.5 cm2 punch has a diameter of 1.784 cm2

, thus it appears that 

the surface area of 227 cm2 is incorrect. 

Page 12 of 95 Page 12 of 95
Page 13 of 56 

COMPLIANCE: 

Signed and dated GLP, Quality Assurance, and Data Confidentiality statements were provided. 

The study sponsor waived claims of confidentiality within the scope of FIFRA Section 10(d) (1) 

(A), (B), or (C). The Study Report indicated that the study was conducted under EPA Good 

Laboratory Practice Standards (40 CFR Part 160). 

ETHICS REVIEW: 

Each worker signed a consent form stating that they were informed of adverse effects and 

expected exposure levels of profenofos. No information on an ethics review was provided. 

GUIDELINE OR PROTOCOL FOLLOWED: Series 875, Occupational and Residential 

Exposure Test Guidelines, Part B, Postapplication Exposure Monitoring Test Guidelines: 

875.2100 (dislodgeable foliar residue dissipation), 875.2400 (dermal exposure), and 875.2500 

(inhalation exposure). 

I. MATERIALS AND METHODS

A. MATERIALS:

1. Test Material: 

Formulation: Curacron® 8E, an EC formulation 

Lot/Batch # formulation: FL-921451/MC 206046 (formulated product) 

Formulation guarantee: 73% ai (8 lb ai/gal) nominal, 73.4% purity analysis (assay date 

7/10/92) 

Purity: 98.1% in technical (Lot 50429-1) 

CAS #: 41198-08-7 

Other Relevant Information: None 

2. Relevance of Test Material to Proposed Formulation(s):

The test product used in this study, Curacron® 8E, appears to be the same product identified on 

the label for Curacron® 8E Insecticide-Miticide (EPA Reg. No. 100-669, dated 7/11/14) based 

on the product name, amount ai (73% ai), and crop use site (cotton). 

B. STUDY DESIGN:

The study protocol (CIBA GEIGY Corporation Protocol No. 127-92 and H.E.RA.C Protocol No. 

92-205HE) was signed on July 10, 1992 by the Study Director. There were 33 amendments and 

40 deviations to the protocol. The amendments and deviations are described in detail in 

Appendix 1 of the Study Report. 

1. Site Description:

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Page 14 of 56 

Test locations: The field phase of the study was conducted at three test sites located in NAFTA 

Region 2. Test sites 1, 2, and 3 were located in Cheraw, SC, McFarlan, NC, and Chesterfield, 

SC, respectively. The sites were approximately 2 to 8 miles from each other. The cotton fields 

were typical for application of the test substance. A control plot and a treatment plot was 

established at each site; however, the distance between the control and treatment plot was not 

provided. 

Areas sprayed, re-entered, and sampled: The treated plot at each site was approximately 25 acres 

and was divided into 10 subplots of approximately 2.5 acres each. 

Meteorological Data: On the days of application and re-entry testing, wind speed, wind 

direction, air temperature, and relative humidities were generally gathered. If weather data were 

not available at the site, then nearby reporting stations were used to gather the data. A 10 year 

NOAA weather summary was also provided for the area around Cheraw, SC (9-13 miles from all 

sites). 

 

During July-October (first application through last sampling), average monthly temperatures 

were 79-61.2°F and were -0.8 to -1.4 °F from normal. Monthly precipitation ranged from 2.41 to 

9.04 inches and was -3.8 to 3.18 inches from normal. 

 

2. Crop Characteristics: 

Crop, variety: Cotton, D & PL90 

Row width, plant spacing: Not reported. 

Stage of growth: Not reported. 

Other products used on crop: Not reported. 

3. Application Rates and Regimes: 

Application rate(s): The target application rate for each of the six applications was 1 lb 

ai/A/application, for a total seasonal rate of 6 lb ai/A/season. Actual application rates ranged 

from 0.95 to 1.23 lb ai/A/application, as shown in Table 1. The current label reports a maximum 

application rate of 0.5 lb ai/A/application, with a maximum seasonal rate of 5 lb ai/A/season. 

Table 1. Actual Application Rates (lb ai/A/application) at Each Test Site 

Application No. Site 1 (Cheraw, SC) Site 2 (McFarlan, NC) Site 3 (Chesterfield, SC) 

1 1.20 1.09 1.12 

2 1.23 1.20 1.12 

3 1.18 1.18 1.2 

4 0.99 0.99 1.18 

5 0.95 0.99 1.04 

6 0.95 0.95 0.95 

Total 6.5 6.4 6.6 

Application Regime: Six applications were made to cotton fields at a 5 to 8 day retreatment 

Page 14 of 95 Page 14 of 95
Page 15 of 56 

interval. Applications were made between 8/11/92 and 9/11/92 at Site 1 (Cheraw, SC), 8/6/92 

and 9/8/92 at Site 2 (McFarlan, NC), and 7/29/92 to 9/2/92 at Site 3 (Chesterfield, SC). The 

label reports a minimum retreatment interval of 5 days. 

Application Equipment: All applications were made using a John-Deere Hi-Boy ground boom 

sprayer fitted with 25 flat fan nozzles on a 40-ft wide boom. Each nozzle was fitted with a #50 

mesh screen. The pressure of the sprayer was approximately 60 psi. 

Spray Volume: The spray volume was 15 to 17 gallons of water per acre. The current label 

reports a minimum spray volume of 3 to 5 GPA for spray solutions diluted with water. 

Equipment Calibration Procedures: The sprayer was calibrated prior to each treatment using 

either a one-gallon plastic jug or directly using a Spraymate Calibrator. When using the plastic 

jug, the gallon per minute was calculated by running the sprayer for a preset period of time 

(usually 30 seconds). The speed of the sprayer was also calibrated prior to each treatment by 

determining the time to spray 10.1 acres. 

Spray Verification: Spray verification was performed by placing 15 cm diameter filter paper (in 

petri dishes) in random spots on the plot prior to applications 1, 3, and 6. The filter paper was 

collected immediately after the application and stored frozen until analysis. The overall average 

deposition (corrected for an average field fortification recovery of 80%) was 1,980 μg/sample 

(n=80) over the course of the study, which was 93.5% of the theoretical amount. 

4. Number and type of workers:

Consent forms were provided for 13 volunteers. The volunteers were male or female and at least 

21 years of age. The volunteers had been instructed on work activities. Several scouters were 

experienced scouters. 

5. Protective clothing: 

The workers wore the following clothing: 

 Outer coveralls (long denim pants and long sleeve chambray shirt) 

 Inner dosimeter (one-piece cotton union suit) 

 New white socks 

 New tennis shoes 

 Clean baseball-style cap 

 Cotton pouches, tied around the waist, for collecting cotton bolls during scouting 

(scouters only) 

The workers did not wear gloves, goggles, face masks, or respirators during monitoring 

activities. The outer and inner dosimeters were washed with detergent water once, rinsed, 

washed twice with water with no detergent, rinsed, dried, and placed into zip-lock bags prior to 

use. 

6. Time Interval(s) for Reentry:

Two reentry intervals were monitored for each worker type (scouting and hoeing). The reentry 

Page 15 of 95 Page 15 of 95
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intervals were 1-2 hours after the last application (0DAT6; after spray had dried) and 24 hours 

after the last application (1DAT6). 

7. Replicates: 

At each test site, five workers (three scouters and two hoers) were monitored at each of the two 

reentry intervals (0DAT6 and 1DAT6). At all sites combined, there were 9 scouter replicates 

and 6 hoer replicates on each reentry day. However, on 1DAT6 at Site 3 (Chesterfield, SC), one 

scouter (replicate 4) dropped out of the study due to heat exhaustion approximately halfway 

through the monitoring period, and an additional worker (replicate 4A) was monitored. 

During each re-entry period one volunteer entered one of the five assigned subplots, and was 

monitored for approximately 4 hours while performing their assigned activity. The beginning 

time of each worker was staggered so that all workers did not end simultaneously. In general the 

workers did not move out of their assigned subplots unless the worker had to be removed from 

the study, took a break from the field activities, emptied apron containing cotton bolls (scouters 

only), or ate lunch. An optional 0.5 hour lunch break was not included in the 4 hour test period. 

The protocol states the North Carolina agricultural extension agent indicated that cotton scouts 

typically spend 2 to 4 hours scouting cotton during a normal day. 

Scouting Activities: The scouters performed the routine below, three times, while zig-zagging 

through the field (going through cotton rows). In most cases the scouts performed all duties and 

recorded the data, but in a few instances the scouts failed to record all data as requested. The 

scouter routine was as follows: 

1. Walk along a row while spreading plants, counting bolls, and observing insect damage. 

2. Pick 50 terminals each hour and observe top and bottom leaves for bollworm eggs and 

live worms. 

3. Pull 100 squares from all locations on the plant. 

4. Record the number of eggs found under the fruiting form. 

5. Record the number of live bollworms under squares’. 

6. Pull 100 young bolls (1/2 to 3/4 mature) from all locations on the plants. 

7. Record the number of live bollworms. 

8. Slice bolls with a sharp knife. 

9. Record damage to the bolls. 

Hoer Activities: The hoers cultivated the weeds in the plot by going systematically through the 

plot with a hoe. 

 

8. Exposure monitoring methodology: 

Dermal: Dermal exposure was monitored using inner dosimeters, outer dosimeters, face/neck 

wipes, and hand washes. Designated personnel suited up the workers and removed samples as 

needed. The field technicians and workers were provided with latex gloves to wear while 

removing each item of clothing to minimize cross contamination. All samples were labelled, 

wrapped, taped, and stored on dry ice immediately after sampling. 

Page 16 of 95 Page 16 of 95
Page 17 of 56 

Outer Dosimeters - The outer dosimeters consisted of a long-sleeved chambray shirt and 

denim long-sleeve pants. These outer dosimeters were worn directly over the inner 

dosimeters. At the end of each monitoring period, the outer dosimeters were carefully 

removed and place in aluminium foil. The dosimeters were then cut into the following four 

sections: (1) left/right arms combined; (2) left/right legs combined; (3) front torso; and (4) 

back torso. Each section was wrapped in aluminium foil and placed into a labelled zip-lock 

bag. 

Inner Dosimeters - The inner dosimeters consisted of a one-piece long-underwear suit 

constructed of 100% cotton. They were worn directly under the outer clothing/dosimeters. 

At the end of each monitoring period, the outer dosimeters were carefully removed and place 

in aluminium foil. The dosimeters were then cut into the following four sections: (1) 

left/right arms combined; (2) left/right legs combined; (3) front torso; and (4) back torso. 

Each section was wrapped in aluminium foil and placed into a labelled zip-lock bag. 

Hand Washes – Hand exposure was assessed by rubbing the workers hands together for 30 

seconds in 250 mL of 0.004% DSS solution. This solution was poured into a prelabeled jar, 

and the procedure was repeated. The two handwashes were pooled as one sample, capped, 

labeled, and prepared for storage and shipment to the laboratory. Samples were collected 

from each worker prior to the beginning of work and at the end of the monitoring period. 

A few deviations were made with respect to handwash sample collection: (1) The handwash 

for volunteer 3 was conducted as a 150 mL wash with 0.004% DSS solution and a 100 mL 

with a 0.04% DSS solution (date not provided, deviation #10), and (2) on 9/3/92 for replicate 

4A, the two 250 mL washes were not pooled, but were collected and analyzed separately. 

Face and Neck Wipes - Face/neck exposure was assessed by wiping the exposed area with 

cotton handkerchiefs which were folded to make a 4.5 inch x 4.5 inch square and saturated 

with 0.004% DSS. Samples were collected by wiping the face area for about 15 seconds and 

the neck area for about 15 seconds. The face/neck wipe was then placed in a labeled jar, 

capped, and prepared for storage and shipment to the laboratory. Samples were collected 

from each worker prior to the beginning of work and at the end of the monitoring period. 

A few deviations were made with respect to face/neck wipe collection: (1) Face/neck wipe 

samples from volunteer 3 were done with 0.04% DSS instead of 0.004% DSS (date not 

provided, deviation #10); (2) on 9/13/12 and on 9/12/12, an additional face/neck wipe with 

distilled water was collected from volunteer 3 after the normal face/neck wipe with DSS; and 

(3) on 9/3/12 volunteer 4 dropped out and an additional face/neck wipe was conducted on 

this volunteer with distilled water prior to a normal facewipe with DSS. 

Inhalation: Airborne concentrations of profenofos in the worker’s breathing zone were 

monitored utilizing a preloaded filter cassette (mixed cellulose-ester filter material) to capture 

particulate matter and chromosorb sorbent tube to capture vapor. The sampling train was 

attached to a Flow-Lite air pump with tygon tubing, and calibrated to 1 L/min. The pumps were 

turned on just prior to entering the treated cotton field and generally left on throughout the test 

Page 17 of 95 Page 17 of 95
Page 18 of 56 

period. On one occasion (Site 3 (Chesterfield, SC), 0DAT6), the air pumps were turned off 

during a lunch break, and turned back on when the workers returned to the field. The air flow 

rates were measured and recorded prior to and after the monitoring period. At the end of the 

monitoring period the air sorbent tubes were capped and both the air sorbent tubes and preloaded 

filter cassettes were wrapped, labeled, and stored on dry ice. 

9. Dislodgeable Foliar Residue Sampling Procedures: 

Method and Equipment: DFR samples consisted of 50 leaf disks which were collected with a 

Birkestrand leaf puncher. The punch size was reported as 2.5 cm2 in the main body of the text. 

The punch samples were collected directly into pre-labelled glass jars. 

Sampling Procedure: At each sampling interval, two replicate samples were collected from the 

treated plot. The 50 leaf discs per sample were taken from random areas of the designated plots. 

Usually, two leaf discs per plant were taken from the most mature part of the cotton plant, 

resulting in using 25 plants per sample. The punches were taken using an alternating quadrant 

system. Plants on the end of the rows were avoided. 

Surface area sampled (two sides): The double sided surface area per leaf punch was 

approximately 5 cm2. 

Total Surface Area per Replicate: The main study text reports the total surface area per replicate 

as 250 cm2; however, in all calculations the study used a surface area of 227 cm2 based on a 

punch diameter of 1.7 cm. Based on the Rabbit Tool website (the manufacturer of Birkestrand 

punches), the 2.5 cm2

 punch has a diameter of 1.784 cm2, thus it appears that the surface area of 

227 cm2

 is incorrect. EPA used a total surface area of 250 cm2 in all calculations. 

Replicates per activity: 

– Replicates per sampling time: At each sampling interval, duplicate DFR samples were 

collected from the treated plots. 

– Number of sampling times: There were a total of 17 sampling events, including nine after the 

last application. 

Times of sampling: Samples were collected prior to and after the first application, after the 

second application, prior to and after the third application, after the fourth and fifth applications, 

prior to and after the sixth (last) application, and at the following intervals after the last 

application: 1, 2, 3, 7, 14, 21, 28 and 35 days. 

Part(s) of foliage sampled: Usually, two leaf discs per plant were taken from the most mature 

part of the cotton plant. 

DFR Dislodging solution: Profenofos residues were dislodged with 0.004% DSS solution. 

DFR Dislodging procedure: Each sample was dislodged twice using 100 mL of the 0.004% 

DSS solution. Dislodging was conducted by shaking the sample on a reciprocating shaker for 10 

Page 18 of 95 Page 18 of 95
Page 19 of 56 

minutes. The two washes were pooled, resulting in a 200 mL sample. On two occasions 

(7/28/92 and 7/29/29), 125 mL of 0.004% DSS solution was used to dislodge samples, resulting 

in a final volume of 250 mL. 

 

DFR Time interval (sample collection to dislodging): The time between sample collection and 

dislodging was not reported. According to the study protocol, leaf punch samples were to be 

transported on wet ice for 30 to 40 minutes to a site where dislodging occurred. 

10. Dislodgeable Cotton Boll Residue Sampling Procedures: 

Method and Equipment: Mature cotton bolls were picked by hand. 

Sampling Procedure: Two samples (five bolls per sample) were collected per area. Cotton bolls 

were collected with or without husks attached. 

Cotton boll weight: The study report noted that the mean weight of 20 cotton bolls (without 

husks) was measured and was reported to be 5.75 g. Based on a sample containing 5 cotton 

bolls, the mean weight per sample was calculated to be 1.44 g. 

Surface area sampled: The surface area of the cotton portion of the cotton bolls was calculated 

by assuming that the boll was sphere shaped. The diameter of 15 bolls collected from one site 

were measured on three separate occasions by inserting a measuring rod. For a 5 boll sample, 

the total surface area was 503 cm2. The surface area of the leaf portion of the cotton bolls was 

calculated by assuming that the carpel was an ellipse. One carpel per boll was removed and the 

width was measured along the widest portion of the leaf. The total surface area for each carpel 

was calculated to be 4.15 cm2. It was determined than the percentage of bolls with 3, 4, or 5 

leaves was <1, 68, and 30%, respectively. Based on a cotton boll containing 4 carpels, and a 

sample containing 5 bolls per sample, the total surface for the carpels per sample was 83 cm2. 

Times of sampling: Two sampling intervals were used at each site. At the first interval mature 

cotton bolls with husks attached were collected. At the second interval mature cotton bolls 

without husks attached were collected. Samples were collected at the following intervals: 

Site 1 (Cheraw, SC): 35DAT6 (with husks) and 61DAT6 (without husks) 

Site 2 (McFarlan, NC): 38DAT6 (with husks) and 44DAT6 (without husks) 

Site 3 (Chesterfield, SC): 36DAT6 (with husks) and 70DAT6 (without husks) 

Dislodging solution: Profenofos residues were dislodged with 0.004% DSS solution. 

Dislodging procedure: Five cotton bolls were pressed into a jar, 125 mL of 0.004% DSS solution 

was added, and the bolls were tamped down below the liquid level. The sample was then shaken 

for approximately 10 minutes, and the wash was poured into a separate jar. The procedure was 

repeated twice, and the first and second washes were combined, resulting in a 250 mL sample. 

 

Dislodging Time interval (sample collection to dislodging): The time between sample collection 

and dislodging was not reported. 

Page 19 of 95 Page 19 of 95
Page 20 of 56 

11. Sample Handling: 

All dermal, inhalation, DFR, and cotton boll samples were labelled, wrapped, taped and stored 

on dry ice immediately after sampling was complete. Samples were stored in coolers on dry ice 

for 1-2 days and were then shipped directly to the analytical laboratory (EN-CAS Analytical 

Laboratories, Winston-Salem, NC) or to a temporary freezer in Monroe, NC prior to final 

shipment to the analytical laboratory. At the laboratory, all samples remained in freezer storage 

(-23° to -27°C) until thawed for subsampling. The length of frozen storage between sample 

collection and analysis was 113-160 days for the treated field samples. Field fortification 

samples were stored for a similar, but longer, length of time. 

12. Analytical Methodology: 

The analytical method used for all matrices was EN-CAS Analytical Method No. ENC-5/91. 

Extraction method: 

Outer & Inner Dosimeters – Profenofos was extracted from the dosimeter sections with 

dichloromethane (DCM) by shaking on a mechanical shaker. An aliquot was collected and 

evaporated to dryness using rotary evaporation. The evaporated sample was reconstituted in 

toluene and analyzed by GC/FPD-P. For the outer dosimeters only, a “high” and “low” approach 

was then used. If the residue was >100 μg then analysis was complete (high method). If residue 

was <100 μg then a new aliquot of the sample was taken, evaporated to dryness, and was taken 

through the low method. The low method involved adding hexane (saturated with acetonitrile) 

to the sample, vacuum filtering, and evaporating to dryness using rotary evaporation. The 

sample was reconstituted in hexane and loaded onto a silica gel Mega Bond-Elut cartridge, and 

profenofos was eluted with DCM/hexane (75/25). The eluate was evaporated to dryness, 

reconstituted in toluene, and analyzed by GC/FPD-P. 

Face/Neck Wipes and Hand Washes - Profenofos was extracted from the face/neck wipe samples 

with hexane/DCM (80/20) using a reciprocating shaker. The sample was decanted into a 

separatory funnel, and the hexane/DCM phase was poured through a sodium sulphate pad and 

concentrated to dryness. The sample was reconstituted in toluene and analyzed by GC/FPD-P. 

Air sorbent tubes - The front portion of the air sorbent tube was extracted with toluene by 

shaking on a mechanical shaker. The extraction solvent was evaporated to dryness and the 

sample was reconstituted in toluene and analyzed by GC/FPD-P. 

Pre-loaded Filter Cassettes - Profenofos was extracted from the pre-loaded filter cassettes with 

DCM using a reciprocating shaker. The extraction solvent was evaporated to dryness and the 

sample was reconstituted in toluene and analyzed by GC/FPD-P. 

DFR and Cotton Boll - Profenofos was extracted from the DFR and cotton boll dislodging 

solutions by adding sodium chloride and partitioning the sample three times with hexanes/DCM 

(80/20). The organic phase was concentrated to dryness using rotary evaporation, then 

reconstituted in toluene and analyzed by GC/FPD-P. 

Page 20 of 95 Page 20 of 95
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Detection methods: All samples were analyzed by GC/ FPD-P. A summary of the GC 

conditions are shown in Table 2 for whole body dosimeters, handwashes and air sorbent tubes, 

and Table 3 for face/neck wipes, preloaded filter cassettes, and cotton leaf and cotton boll 

dislodging solutions. 

Table 2. Summary of Typical GC/FPD-P Conditions for Whole Body Dosimeters, Handwashes and Air 

sorbent tubes 

Instrument (GC): Hewlett-Packard 5890 

Column: Fused silica megabore capillary 30-m x 0.32-mm D-17 column, 0.25-

μm film thickness 

Temperature: Injector: 240 °C 

Detector: 250 °C 

Program: 

Oven Temp = 205°C 

Hold Time = 4 min 

Ramp = 10°C /min 

Final Oven Temp. = 250°C 

Final Hold Time = 12 min 

Injection: 2 -4 μL, splitless 

Gas: Carrier: Helium = 4.4 mL/min 

Detector: Hydrogen = 62 mL/min, Air = 104 mL/min 

Approximate Retention Time: 6.1 minutes 

Mode: Phosphorus 

Table 3. Summary of Typical GC/FPD-P Conditions for Face/Neck Wipes, Preloaded Filter Cassettes, 

Cotton Leaf and Cotton Boll Dislodging Solutions 

Instrument (GC): Hewlett-Packard 5890 

Column: Fused silica megabore capillary 15-m x 0.542-mm DB-5 column, 1.5-

μm film thickness 

Temperature: Injector: 240°C 

Detector: 250°C 

Program: 

Oven Temp = 200°C 

Hold Time = 10 min 

Injection: 5 μL, splitless 

Gas: Carrier: Helium = 16 mL/min 

Detector: Hydrogen = 90 mL/min, Air = 100 mL/min 

Total Run Time: 12 minutes (20 min for CA DFR samples) 

Approximate Retention Time: 4.7 minutes 

Mode: Phosphorus 

Page 21 of 95 Page 21 of 95
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Method validation: The analytical method used to quantify residues of profenofos in each matrix 

was validated on control samples prior to the determination of the residue in the treated samples 

for this study. 

Outer Dosimeters -- Control outer whole body dosimeter arm sections (chambray) were fortified 

at three levels: 1.0, 10 and 100 μg/sample. The overall mean recovery was 103 ± 7.5% (n=3) for 

fortifications with analytical standard and 91 ± 9.1% (n=9) for fortifications with the test 

formulation. Control outer whole body dosimeter leg sections (denim) were fortified at four 

levels: 1.0, 10, 100, and 1,000 μg/sample. The overall mean recovery was 114 ± 12% (n=3) for 

fortifications with analytical standard and 84 ± 12% (n=15) for fortifications with the test 

formulation. The validated LOQ was 1 μg/sample for the “low” method and 100 μg/sample for 

the “high” method; the LOD was not reported. 

Inner Dosimeters -- Control inner whole body dosimeter sections were fortified at one level: 1.0 

μg/sample. The overall mean recovery was 76 ± 18% (n=3) for fortifications with analytical 

standard and 87 ± 12% (n=9) for fortifications with the test formulation. The validated LOQ was 

1.0 μg/sample; the LOD was not reported. 

Handwashes -- 0.004% DSS solution was fortified at three levels: 0.00015, 0.0015, and 0.015 

μg/mL. The overall mean recovery was 97 ± 3.8% (n=3) for fortifications with analytical 

standard and 88 ± 11% (n=9) for fortifications with the test formulation. The validated LOQ was 

0.00015 μg/mL; the LOD was not reported. 

Face/neck Wipes -- Control face/neck wipe samples were fortified at four levels: 0.05, 0.5, 5 and 

250 μg/sample. The overall mean recovery was 117 ± 2.1% (n=3) for fortifications with 

analytical standard and 91 ± 16% (n=12) for fortifications with the test formulation. The 

validated LOQ was 0.05 μg/sample; the LOD was not reported. 

Air sorbent tubes -- Air sampling tubes were fortified at three levels: 0.1, 1.0, and 25 μg/section. 

The overall mean recovery was 80 ± 19% (n=3) for fortifications with analytical standard and 86 

± 16% (n=12) for fortifications with the test formulation. The validated LOQ was 0.1 μg/sample; 

the LOD was not reported. Profenofos breakthrough was investigated by fortifying the front 

sections of the air sorbent tubes with profenofos at 0.1 and 1.0 μg/sample, and drawing air 

through the sample for 6 hours at a rate of 1 L/min. Tests were done at a humidity of 30% and 

90%. Profenofos was not found in the back sections of any air sorbent tubes. At 30% humidity, 

recoveries ranged from 33-82% at the low level and 128 to 142% at the high level. At 90% 

humidity, recoveries ranged from 73-101% at the low level and 134 to 138% at the high level. It 

was noted that under the 30% humidity conditions it was difficult to remove the chromosorb 

material from the glass tube. An apparent electrostatic charge caused sticking to the inside glass 

walls, which may have caused the lower than normal recovery at the 0.1 μg/sample level. 

Preloaded Filter Cassettes -- Preloaded filter cassettes were fortified at three levels: 0.1, 1.0, and 

25 μg/section. The overall mean recovery was 98 ± 26% (n=3) for fortifications with analytical 

standard and 103 ± 14% (n=12) for fortifications with the test formulation. The validated LOQ 

was 0.1 μg/sample; the LOD was not reported. 

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Dislodgeable Foliar Residues -- Cotton leaf 0.004% DSS solution was fortified at three levels: 

0.1, 1.0, and 25 μg/section. The overall mean recovery was 120% (n=2) for fortifications with 

analytical standard and 105 ± 19% (n=12) for fortifications with the test formulation. The 

validated LOQ was 0.003 μg/cm2; the LOD was not reported. Since both cotton bolls and leaves 

were extracted with 0.004% DSS solution, the cotton leaf validation was considered acceptable 

for cotton bolls. The LOQ for cotton bolls was 0.003 μg/mL (0.0015 μg/cm2). 

Instrument performance: A series of calibration standards were injected with each set to quantify 

residues in the samples. The standards are injected after every 2 to 3 samples throughout the GC 

run. Typical calibration curves were provided for handwash and cotton leaf dislodgeable 

solution. The curves showed calibration standard concentrations ranging from 0.02 to 5 ng and 

r2 values of 0.998 to 0.999. 

Quantification: Residue levels were calculated from linear regression standard curves. 

13. Quality Control: 

Lab Recovery: A typical analysis set included at least two laboratory fortified samples and one 

control blank. A summary of the laboratory recoveries is presented in Table 4 below. Overall 

average recoveries ranged from 78 to 93% per matrix. All procedural recoveries were corrected 

for contribution from the control. Profenofos residues in the control were <LOQ for outer and 

inner WBD, air sorbent tubes, preloaded filter cassettes, and cotton leaf DFR. Profenofos 

residues in the control were <LOQ to 0.059 μg for face/neck wipes, <LOQ to 0.00051 μg for 

handwashes, and <LOQ to 0.006 μg/mL for cotton bolls. 

Table 4. Summary of Laboratory Fortification

Matrix Fortification Levels n Overall Recovery ± Standard 

Deviation (%)1

Outer WBD 1 – 20,000 μg 26 83 ± 17 

Inner WBD 0.1 – 20,000 μg 31 89 ± 19 

Face/Neck Wipes 0.05 – 5 μg 20 78 ± 10 

Handwashes 0.00015- 10 μg/mL 24 87 ± 13 

Air Sorbent tubes 0.1 – 30 μg 9 90 ± 13 

Preloaded Filter Cassettes 0.1 – 1 μg 12 89 ± 12 

Cotton Leaf DFR 0.003 – 300 μg/mL 34 90 ± 12 

Cotton Bolls 0.03 – 0.03 μg/mL 8 93 ± 27 

1. Recoveries were corrected for contribution from the control. 

Field blanks: For each site, duplicate field blank samples were prepared for each dermal and 

inhalation matrix at each reentry interval. For DFR samples, single field blank samples were 

prepared on each application day as well as the day before application 1 and 3. The samples were 

exposed to the environment in the same manner as the field fortification samples (see below). 

Residues of profenofos were not detected in any control air sorbent tube samples, but were 

detected in some samples for all other matrices (up to 34xLOQ), as shown in Table 5. The study 

states that residues were probably detected due to the proximity of the sample preparation area to 

the field being sprayed. Field residues were not corrected for residues detected in the field blank 

samples. 

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Table 5. Profenofos Residues1 in Field Blank Samples

Matrix Site 1 (Cheraw, SC) Site 2 (McFarlan, NC) Site 3 (Chesterfield, SC) 

Outer WBD 1.2 - 3.64 μg <LOQ 8.3 - 48.2 μg 

Inner WBD <LOQ - 1.88 μg <LOQ 1.71 – 23.9 μg 

Face/Neck Wipes <LOQ – 0.167 μg/mL <LOQ - 0.074 μg/mL <LOQ - 0.119 μg/mL 

Handwashes <LOQ-0.0002 μg/mL 0.00019-0.00127 μg/mL 0.00057-0.00533 μg/mL 

Air Sorbent tubes <LOQ <LOQ <LOQ 

Preloaded Filter 

Cassettes 

<LOQ <LOQ <LOQ – 0.518 

Cotton Leaf DFR <LOQ <LOQ <LOQ 

Cotton Bolls <LOQ <LOQ - 0.034 μg/mL <LOQ 

1. Residues shown are not corrected for field fortification recovery. 

Field recovery: Field fortification samples for all dermal, inhalation, and cotton boll matrices 

were prepared at one fortification level (handwash, face/neck wipes, air filters, and air sorbent 

tubes) or at two fortification levels (inner and outer dosimeters, DFRs and cotton bolls). Field 

fortification samples for DFRs were prepared in triplicate on -1DAT6, 7DAT6, and 35DAT6. 

For other matrices, field fortification samples were prepared on each sample collection day. 

Profenofos spiking solutions were prepared at the analytical laboratory and brought to the field 

sites. After spiking control samples, the samples were exposed to the environment for 

approximately the same duration as the field samples. However, for inner and outer dosimeter 

sections and air samples, the duration of exposure was 4-7 hours, which was longer than the field 

samples to accommodate supervision of undressing volunteers. Handwash and face/neck wipe 

samples were exposed for 5 to 8 minutes and 5 to 10 minutes, respectively. Air was drawn 

through the air samples at a rate of 1 L/min. 

A summary of the field fortification recoveries are provided in Tables 6 through 13 for each 

matrix. The recoveries were not corrected for any apparent residues detected in the field control 

samples. Recoveries were corrected for concurrent laboratory recovery, if <100%. Average 

recoveries were generally between 70 and 120%, with standard deviations <20%, with a few 

exceptions as follows: 

For outer whole body dosimeters, standard deviations were 25.1-55.9% for two sets at the low 

fortification level (0DAT6 at Site 1 (Cheraw, SC) and 1DAT6 at Site 2 (McFarlan, NC)). For 

inner whole body dosimeters, average recoveries were 37.0-64.9% for all low fortification sets 

and standard deviations were 23.0-29.0% for 3 of the 4 sets at Site 2 (McFarlan, NC). No 

explanation was provided for the extremely low recoveries. For face/neck wipes, the standard 

deviation was 29.8% for the high fortification level at Site 2 (McFarlan, NC) on 1DAT6. For 

DFRs, the standard deviations were 21.2 - 27.2% for three sets (high fortification level for Site 1 

(Cheraw, SC), both levels for Site 2 (McFarlan, NC)). For cotton bolls, average recoveries were 

65.8-68.9% for the high level sets at Site 3 (Chesterfield, SC) and standard deviations were 40.1-

42.4% for both low and high sets at the 36DAT6 interval for Site 3 (Chesterfield, SC). 

The fortification levels were not within range or did not bracket the field residues for the 

following matrices: 

 For face/neck wipes, the fortification level (200 μg) was at least an order of magnitude 

higher than the residue levels detected in the post-exposure treated samples (0.446 to 25.8 

μg). 

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 For inner dosimeters, the low fortification level (200 μg) was within the range of the 

treated samples (1.53 to 1,439 μg), but the high fortification level (20,000 μg) was an 

order of magnitude higher than the residue levels. 

 For DFRs, the low fortification level (200 μg) was within range of the treated samples 

(0.80 to 1,434 μg), but the high fortification level (20,000 μg) was an order of magnitude 

higher than the residue levels. 

 For air filters, the fortification level (25 μg) was higher than the residue levels detected in 

the treated samples (0.083 to 1.61 μg). 

The average recovery results were used as multipliers to adjust, or correct, all measured field 

samples. If multiple fortification levels were used, the average recovery from the fortification 

level closest to the measured field sample was used to adjust the field samples. The midpoint 

between each fortification level (i.e. 10,100 μg for whole body dosimeters and cotton boll 

samples and 40.4 μg/cm2

 for DFR samples) was used as the threshold for determining which 

average recovery to use. 

Table 6. Field Fortification Recoveries for Outer Whole Body Dosimeters1

Sample 

Interval 

Fortification 

Level 

(μg/sample) 

Count 

Recoveries2 (%) 

Range Average ± Standard Deviation 

Site 1 (Cheraw, SC) 

0DAT6 

200 5 42.0 - 160 92.5 ± 55.9

20,000 5 86.9 - 102 93.6 ± 6.4 

1DAT6 

200 7 58.5 - 88 74.7 ± 10.8 

20,000 9 100 - 137 120 ± 10.2 

Site 2 (McFarlan, NC) 

0DAT6 

200 5 94.0 - 136 108 ± 16.2 

20,000 5 95.5 - 107 103 ± 4.5 

1DAT6 

200 5 65.5 - 127 85.1 ± 25.1

20,000 5 107- 127 115 ± 7.6 

Site 3 (Chesterfield, SC) 

0DAT6 200 5 94.0 - 110 104 ± 6.6 

1DAT6 

200 5 87.0 - 130 98.2 ± 17.7 

20,000 5 98.7- 118 108 ± 7.0 

1. Leg, arm, front torso, and back torso sections were fortified. Recoveries from all sections were combined 

for summary statistics. 

2. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%. 

Table 7. Field Fortification Recoveries for Inner Whole Body Dosimeters1

Sample 

Interval 

Fortification 

Level 

(μg/sample) 

Count 

Recoveries2 (%)

Range Average ± Standard Deviation 

Site 1 (Cheraw, SC) 

0DAT6 

200 5 44.2 - 89.0 55.9 ± 18.8

20,000 2 97.6 - 98.6 98.1 ± 0.7 

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Table 7. Field Fortification Recoveries for Inner Whole Body Dosimeters1

Sample 

Interval 

Fortification 

Level 

(μg/sample) 

Count 

Recoveries2 (%)

Range Average ± Standard Deviation 

1DAT6 

200 5 44.6 - 65.0 58.8 ± 8.4

20,000 9 56.1 - 118 93.7 ± 17.3 

Site 2 (McFarlan, NC) 

0DAT6 

200 5 30.4 - 43.0 37.0 ± 4.9

20,000 5 65.0 - 124 86.9 ± 23.0

1DAT6 

200 5 48.0 - 117 64.9 ± 29.0

20,000 4 60.4 - 131 96.2 ± 28.8

Site 3 (Chesterfield, SC) 

0DAT6 

200 5 33.7 - 40.1 38.1 ± 2.7

20,000 5 54.8 - 88.1 73.5 ± 15.0 

1DAT6 

200 5 34.9 - 40.8 38.0 ± 2.8

20,000 5 56.5 - 99.1 79.2± 16.1 

1. Leg, arm, front torso, and back torso sections were fortified. Recoveries from all sections were combined 

for summary statistics. 

2. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%. 

Table 8. Field Fortification Recoveries for Handwashes 

Sample 

Interval 

Fortification 

Level 

(μg/mL) 

Count 

Recoveries1 (%)

Range Average ± Standard Deviation 

Site 1 (Cheraw, SC) 

0DAT6 0.4 5 75.4 - 99.4 89.7 ± 9.5 

1DAT6 0.4 5 89.3 - 116 99.5 ± 10.0 

Site 2 (McFarlan, NC) 

0DAT6 0.4 5 73.3 - 96.6 83.7 ± 10.7 

1DAT6 0.4 5 70.7 - 93.3 78.8 ± 8.6 

Site 3 (Chesterfield, SC) 

0DAT6 0.4 5 76.5 - 94.4 86.1 ± 6.9 

1DAT6 0.4 5 92.0- 107 98.5 ± 5.5 

1. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%.

Table 9. Field Fortification Recoveries for Face/Neck Wipes 

Sample 

Interval 

Fortification 

Level (μg) Count 

Recoveries1 (%)

Range Average ± Standard Deviation 

Site 1 (Cheraw, SC)

0DAT6 200 5 68.5 - 97.0 84.9 ± 10.9 

1DAT6 200 5 62.0 - 111 88.5 ± 19.3 

Site 2 (McFarlan, NC)

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0DAT6 200 5 67.5 - 86.5 75.5 ± 8.2 

1DAT6 200 5 42.5 - 112 95.7 ± 29.8

Site 3 (Chesterfield, SC)

0DAT6 200 5 52.0 - 96.0 77.1 ± 16.8 

1DAT6 200 5 62.5 - 98.0 83.0± 14.0 

1. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%.

Table 10. Field Fortification Recoveries for Air Sorbent Tubes 

Sample 

Interval 

Fortification 

Level (μg) Count 

Recoveries1 (%)

Range Average

Site 1 (Cheraw, SC) 

0DAT6 25 2 79.6 - 99.6 89.6 

1DAT6 25 2 91.2 - 105 98.2 

Site 2 (McFarlan, NC) 

0DAT6 25 2 86.4 - 86.8 86.6 

1DAT6 25 2 88.4 - 94.4 91.4 

Site 3 (Chesterfield, SC) 

0DAT6 25 2 75.6 - 81.6 78.6 

1DAT6 25 1 (37)2 - 75.2 75.2 

1. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%. 

2. One replicate was identified as an outlier and was not used in the summary calculations. 

Table 11. Field Fortification Recoveries for Preloaded Filter Cassettes 

Sample 

Interval 

Fortification 

Level (μg) Count 

Recoveries1 (%)

Range Average

Site 1 (Cheraw, SC) 

0DAT6 25 2 92.0 - 99.6 95.8 

1DAT6 25 2 65.2 - 75.6 70.4 

Site 2 (McFarlan, NC) 

0DAT6 25 2 95.6 - 98.8 97.2 

1DAT6 25 2 86.0 - 89.2 87.6 

Site 3 (Chesterfield, SC) 

0DAT6 25 2 74.0 - 88.0 81.0 

1DAT6 25 2 95.6 - 107 101 

1. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%.

Table 12. Field Fortification Recoveries for DFR 

Sample Interval Fortification 

Level (μg) Count 

Recoveries1 (%)

Range Average ± Standard Deviation 

Site 1 (Cheraw, SC) 

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Table 12. Field Fortification Recoveries for DFR 

Sample Interval Fortification 

Level (μg) Count 

Recoveries1 (%)

Range Average ± Standard Deviation 

-1DAT6, 7DAT6, 35DAT6 200 6 69.5 - 118 103 ± 17.1 

-1DAT6, 7DAT6, 35DAT6 20,000 6 82.4 - 151 107 ± 27.2

Site 2 (McFarlan, NC) 

-1DAT6, 7DAT6, 35DAT6 200 6 91.0 - 152 112 ± 23.2

-1DAT6, 7DAT6, 35DAT6 20,000 6 81.7 - 131 105 ± 21.2

Site 3 (Chesterfield, SC) 

-1DAT6, 7DAT6, 35DAT6 200 8 61.5 - 115 86.3 ± 19.1 

-1DAT6, 7DAT6, 35DAT6 20,000 8 77.5 - 137 95.2± 19.6 

1. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%.

Table 13. Field Fortification Recoveries for Cotton Bolls 

Sample Interval Fortification 

Level (μg) Count 

Recoveries1 (%)

Range Average ± Standard Deviation

Site 1 (Cheraw, SC) 

35DAT6 

(Boll + Carpel) 

200 2 105 - 119 112 ± 9.5 

20,000 2 86.1 - 112 99.1 ± 18.3 

61DAT6 

(Carpel) 

200 2 92.0 - 103 97.3 ± 7.4 

20,000 2 79.5 - 87.25 83.4 ± 5.5 

Site 2 (McFarlan, NC)

38DAT6 

(Boll + Carpel) 

200 2 113 - 123 118 ± 7.1 

20,000 2 103 - 106 104 ± 2.2 

44DAT6 

(Carpel) 

200 2 94.5 - 96.5 95.5 ± 1.4 

20,000 2 94.0 - 96 95.0 ± 1.4 

Site 3 (Chesterfield, SC)

36DAT6 

(Boll + Carpel) 

200 2 60.5 - 121 90.5 ± 42.4

20,000 2 40.5 - 97.3 68.9 ± 40.1

70DAT6 

(Carpel) 

200 2 99.0 - 101 99.8 ± 1.1 

20000 2 58.1 - 73.5 65.8± 10.9 

1. Recoveries were calculated by reviewer using the reported residues found. The reported residues were 

corrected for concurrent laboratory recovery, if <100%.

 

Formulation: Curacron® 8E is an emulsifiable concentrate formulation containing a nominal 

73% of ai (8 lb ai/gal). Duplicate samples of formulation used at each site were analyzed. The 

mean concentration of profenofos was 1.07 ± 0.092 g/mL, which is 89.6% of theoretical. 

 

Tank mix: Tank mix samples were collected for each application at each site in duplicate prior 

Page 28 of 95 Page 28 of 95
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to each application. The mean concentration of profenofos was 7,157 ± 656 μg/mL (n=18), 

which is 85 ± 30% of theoretical. 

Travel Recovery: Travel recovery samples were not prepared. 

Storage Stability: According to the analytical method protocol, storage stability tests were to be 

conducted for all matrices; however, the results were not reported. As reported in MRID 

42851304, a freezer storage stability study was conducted in which Aerosol OT dislodging 

solution was fortified with profenofos at 0.05 μg/mL and analyzed after 0, 1 and 3 months of 

frozen storage. After correction for concurrent recovery, storage stability recoveries were 106, 88 

and 88%, respectively. The field fortification samples demonstrated the stability of profenofos 

during storage. All field fortification samples were stored for a greater length of time than the 

treated samples prior to analysis. 

II. RESULTS AND CALCULATIONS

DFR: Profenofos values for DFR samples were presented in the study in units of μg/sample with 

correction for concurrent laboratory recovery (if <100%), and in μg/cm2 with an additional 

correction for the overall average field fortification recovery. The Registrant used a leaf surface 

area of 227 cm2

/sample for calculations. Using the reported μg/sample values (already corrected 

for concurrent laboratory recovery), EPA calculated DFRs in μg/cm2

 with correction for site 

specific average field fortification values from each recovery level (refer to Table 12). EPA used 

a leaf surface area of 250 cm2/sample for calculations. 

Tables 14-16 provide a summary of the profenofos DFR values for the cotton foliage at Sites 1, 

2, and 3, respectively. In general, DFRs declined rapidly within the first week after the last 

application, and then remained at low levels through the end of the sampling period. Residues 

did not decline to <LOQ (0.003 μg/cm2) by 35DAT6. 

The average DFR (and percent of application rate) at Site 1 (Cheraw, SC) was the highest at the 

0DAT5 interval (2.83 μg/cm2

; 26.5%). After the last application, the average DFR was a 

maximum of 1.74 μg/cm2

 (16.3%) at 0DAT6, declined to 0.40 μg/cm2 (3.8%) at 1DAT6, and 

continued to decline to 0.0047 μg/cm2

 (0.04%) at 35DAT6. 

The average DFR (and percent of application rate) at Site 2 (McFarlan, NC) was the highest at 

the 0DAT2 interval (3.99 μg/cm2

; 29.7%). After the last application, the average DFR was a 

maximum of 1.82 μg/cm2

 (17.1%) at 0DAT6, declined to 0.251 μg/cm2 (2.4%) at 1DAT6, and 

continued to decline to 0.0046 μg/cm2

 (0.04%) at 35DAT6. 

The average DFR (and percent of application rate) at Site 3 (Chesterfield, SC) was the highest at 

the 0DAT5 interval (5.19 μg/cm2

; 44.5%). After the last application, the average DFR was a 

maximum of 2.48 μg/cm2

 (23.3%) at 0DAT6, declined to 1.54 μg/cm2 (14.4%) at 1DAT6, and 

continued to decline to 0.0056 μg/cm2

 (0.05%) at 35DAT6. Actual DFRs on 0DAT6 were 7 to 

12 times higher than the predicted DFRs on 0DAT6. 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos, using the natural log of average DFR values. Using the 0DAT6 to 35DAT6 data, the 

Page 29 of 95 Page 29 of 95
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Registrant calculated half-lives of 5 days (r = -0.85) for Site 1 (Cheraw, SC), 4.9 days (r = -0.77) 

for Site 2 (McFarlan, NC), and 4.6 days (r = -0.79) for Site 3 (Chesterfield, SC). The Registrant 

also performed regressions using the 0DAT6 through 7DAT6 data only, which assumes a 

biphasic curve. The Registrant calculated half-lives of 1.2 days (r = -0.91) for Site 1 (Cheraw, 

SC), 1.1 days (r = -0.80) for Site 2 (McFarlan, NC), and 0.86 days (r = -0.95) for Site 3 

(Chesterfield, SC). 

EPA first assumed first-order dissipation kinetics and conducted linear regression analysis using 

the natural logarithm of the average DFR values from 0DAT6 to 35DAT6. EPA's estimated halflife values were 5.1 days (R2

= 0.7132) for Site 1, 5.7 days (R2= 0.6351) for Site 2, and 4.7 days 

(R2= 0.6271) for Site 3. However, the regression analysis did not appear visually to be a good fit 

for the data, and the actual DFRs on 0DAT6 were 7 to 12 times higher than the predicted DFRs 

on 0DAT6. Therefore, EPA did additional analysis and conducted a biphasic (“hockey stick”) 

regression analysis using Excel’s Solver, and the corrected average DFRs from immediately after 

the last application through the last sampling interval. This regression analysis appears (visually) 

to be a better fit of the data, and provides predicted Day 0 values of 2.3 μg/cm2

, 3.0 μg/cm2, and 

2.7 μg/cm2, for Site 1 (Cheraw, SC), Site 2 (Chesterfield, SC), and Site 3 (McFarlan, NC), 

respectively. 

Dermal: Profenofos values for dermal matrix samples were presented in the study in units of 

μg/sample, with correction for concurrent laboratory recovery (if <100%) and for the overall 

average field fortification recovery for each specific matrix. Using the reported μg/sample 

values (already corrected for concurrent laboratory recovery), EPA calculated dermal exposures 

for each matrix in μg/sample and μg/hour with correction for site specific average field 

fortification values from each recovery level (refer to Tables 6-11). For all replicates, EPA used 

the nominal work duration of 4 hours. For values <LOQ, EPA used a value of 1⁄2 LOQ in 

calculations. It should be noted that one scouter on 1DAT6 dropped out early because of heat 

exhaustion and was replaced with a new worker. EPA did not include the replicate which 

dropped out in summary calculations. 

For scouts and hoers at all sites combined, the Registrant provided mean exposure (μg/sample) 

for each matrix, and summed the average exposures for the inner dosimeter, handwash, and 

face/neck wipes to obtain average total dermal exposure values for scouts and hoers on each reentry day. The Registrant did not calculate total dermal exposures per replicate. 

On a per replicate basis, EPA calculated total dermal exposure as the sum of the inner dosimeter, 

total head, and hand exposures, and potential dermal exposure as the sum of the inner dosimeter, 

outer dosimeter, total head, and hand exposures. The results are presented in Tables 18-21 in 

terms of transfer coefficients (μg/cm2

), and are summarized for each worker activity at each site. 

Transfer coefficients are dermal exposure (μg/hr) divided by the average DFR (μg/cm2) on the 

reentry day. The average DFRs used for 0DAT6 and 1DAT6 intervals were 1.74 and 0.403 

μg/cm2

 at Site 1 (Cheraw, SC), 1.82 and 0.251 μg/cm2 at Site 2 (McFarlan, NC), and 2.48 and 

1.54 μg/cm2

 at Site 3 (Chesterfield, SC). 

In addition to the adjustments and assumptions already discussed above (i.e. field fortification 

Page 30 of 95 Page 30 of 95
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correction and use of 1⁄2 LOQ for values reported as <LOQ), the following procedures were used 

to calculate exposure values and transfer coefficients: 

Pre-exposure values: Handwash and face/neck wipe samples were collected prior to and after 

the exposure event. Prior to the exposure event, residues in the handwash samples were <LOQ 

in 10 of 30 replicates and ranged from to 0.12 to 6.31 μg/sample in 20 of 30 replicates (0.04 to 

39% of the post-exposure residues). For face/neck wipe samples, residues were <LOQ (<0.05 

μg/sample) in 12 of 30 replicates and ranged from to 0.025 to 1.35 μg/sample in 18 of 30 

replicates (0.34 to 58% of the post-exposure residues). The Registrant subtracted out the preexposure residues from the post-exposure residues to obtain net hand exposure values. EPA 

used only the post-exposure values in the calculation of hand exposure values. No explanation 

was provided for the detection of profenofos in the pre-exposure samples. 

Non-face/non-neck head exposure: No samples were collected from the non-face/non-neck 

regions of the head. Therefore, exposure for this area was estimated by extrapolating the 

face/neck wipe residue, value based on relative surface areas of the face/neck area that was 

wiped with the rest of the head that was not wiped. An adjustment factor of 0.61 was applied to 

the face/neck residue to determine the non-face/non-neck reside. The factor was calculated as a 

ratio of the percent of total body surface area of the non-face/non-neck area to the face/neck area 

(2.95%/4.84% for males and 3.05%/5.01% for females). Total head exposure was calculated as 

the sum of the face/neck residue and the non-face/non-neck residue. 

Method extraction adjustment: In order to account for potential residue collection method 

inefficiencies for handwash and face/neck wipe field study measurements, the average 

contribution of hand and total head exposures to total dermal exposure was calculated across all 

workers in each statistical summary set. The following four sets required an upward adjustment 

of the hand and total head exposure by a factor of 2 because the combined contribution of hand 

and total head exposure to total dermal exposure fell within the range of 20 to 60%: Site 1 

(Cheraw, SC) Scouters on 0DAT6, Site 2 (McFarlan, NC) Scouters on 0DAT6, Site 1 (Cheraw, 

SC) Hoers on 0DAT6, and Site 2 (McFarlan, NC) Hoers on 0DAT6. The average measured 

exposure contribution from hands and total head contributed less than 20% for the other 

statistical summary sets, therefore no action was required for these sets. 

Other issues to note include: 

 The study did not specifically state which volunteer was assigned to which replicate. 

EPA assumed that each volunteer was assigned a unique replicate which remained 

consistent for each matrix collected from the volunteer. 

 For the face/neck wipe samples at Site 1 (Cheraw, SC) and 2 on 1DAT6, it appears that 

the study did not assign the correct worker activity to some of the samples. EPA used the 

worker activity assigned to the replicate for the other matrices. 

 As noted in deviation no. 38, samples at Site 1 (Cheraw, SC) were labelled as Site 3 

(Chesterfield, SC) and samples at Site 3 (Chesterfield, SC) were labelled as Site 1 

(Cheraw, SC) for all dermal and inhalation samples. 

 Handwash samples for replicate 4A (scouter at Site 3 (Chesterfield, SC) on 1DAT6) were 

divided into two 250 mL jars and analyzed separately. It appears that the study 

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incorrectly used a volume of 500 mL to calculate the residues in μg/sample for these 

samples. EPA used a volume of 250 mL to calculate the residues in μg/sample for these 

samples. 

 One worker at Site 1 (Cheraw, SC) and Site 3 (Chesterfield, SC) on 1 DAT6 received a 

face/neck wipe with DSS and with water. Both samples were analyzed, and the results 

were combined. 

 

Transfer coefficients are summarized in Tables 18-21. For scouters, average transfer coefficients 

for total dermal exposure were 176, 123, and 237 cm2

/hr on 0DAT6 for Sites 1, 2, and 3, 

respectively, and 330, 318, and 293 cm2/hr on 1DAT6 for Sites 1, 2, and 3, respectively. For 

hoers, average transfer coefficients for total dermal exposure were 86.9, 96.9, and 200 cm2

/hr on 

0DAT6 for Sites 1, 2, and 3, respectively, and 192, 198, and 122 cm2/hr on 1DAT6 for Sites 1, 2, 

and 3, respectively. 

Table 22 summarizes the distribution of residue on body parts. Based on average values of 

transfer coefficients for total dermal exposure, body parts with significant residues (i.e., >10%) 

were the arm, leg and hand. For scouters and hoers on 0DAT6, the average distribution was 

approximately 30% to the legs, arms, and hands each. A similar distribution was observed for 

hoers on 1DAT6 (legs, arms and hands each receiving an average of 24-33%). For scouter on 

1DAT6, the majority of the distribution was on the legs (average of 59%), with 23% on the arms, 

and only 8.1% on the hands. 

Table 23 summarizes the percent penetration from the outer to inner dosimeters. Average 

penetration was highest for the arms (29 to 40%). Average penetration for the other regions 

ranged from 3.8 to 9.3%. 

Inhalation: Profenofos values for inhalation samples were presented in the study in units of 

μg/sample, with correction for concurrent laboratory recovery (if <100%) and for overall average 

field fortification recovery. Air sorbent tube samples did not require correction because all 

residues were <LOQ. Using the reported μg/sample values (already corrected for concurrent 

laboratory recovery), EPA calculated air concentrations in μg/m3

 and inhalation exposures in 

μg/hr, with correction for site specific average field fortification values from each recovery level 

(refer to Table 10 for air sorbent tubes and Table 11 for pre-loaded filter cassettes). For values 

<LOQ, EPA used a value of 1⁄2 LOQ in calculations. EPA summed the preloaded filter cassette 

and air sorbent tube residues to provide total profenofos residues. The airborne concentration of 

profenofos was then calculated by dividing the corrected total residue value by the total volume 

of air drawn by the personal sampler over the sampling duration. The air concentrations were 

then adjusted for the NAFTA recommended inhalation rate of 1.0 m3

/hr (light activity) for 

scouters and 1.6 m3

/hr (moderate activity) for hoers. 

The results are shown in Table 24-25. For scouters, average inhalation exposure was 5.48, 4.26, 

and 5.82 μg/hr on 0DAT6 for Sites 1, 2, and 3, respectively, and 2.05, 1.52, and 0.95 μg/hr on 

1DAT6 for Sites 1, 2, and 3, respectively. For hoers, average inhalation exposure was 7.47, 6.24, 

and 7.83 μg/hr on 0DAT6 for Sites 1, 2, and 3, respectively, and 2.86, 2.21, and 2.28 μg/hr on 

1DAT6 for Sites 1, 2, and 3, respectively. 

Page 32 of 95 Page 32 of 95
Page 33 of 56 

Cotton Boll: Profenofos values for cotton boll samples (with and without carpel) were presented 

in the study in units of μg/sample and in μg/cm2 with correction for concurrent laboratory 

recovery (if <100%). No field fortification recovery correction was applied. Using the reported 

μg/sample values (already corrected for concurrent laboratory recovery), EPA calculated values 

in ug/g (for cotton bolls only) and μg/cm2 with correction for site specific average field 

fortification values from each recovery level. 

Table 26 provides a summary of the profenofos values for all sites. Residues were <LOQ in all 

cotton boll only samples collected at 44-70DAT6. In the boll+carpel samples collected at 35-

38DAT6, the average profenofos values were 0.0015 to 0.0025 μg/cm2. 

III DISCUSSION:

A. LIMITATIONS OF THE STUDY:

The following concerns are noted with respect to the worker exposure study (Series 875.2400 

and 875.2500 Guidelines): 

 Fifteen workers were monitored at each interval; however, these were divided between 

all three sites and both worker types. On a per site basis, only three scouters and two 

hoers were monitored at each interval. 

 The exact monitoring time for each worker replicate was not provided. It was assumed 

for all calculations that each worker was monitored for the nominal 4 hour work duration. 

 The following issues with field fortification are noted: 

o Single field fortification levels were used for handwash, face/neck wipe, air filter, 

and air sorbent tube samples. 

o The average low level field fortification recoveries for the inner whole body 

dosimeters were 37.0-64.9%. No explanation for the extremely low recoveries 

was provided. 

o The fortification levels were not within range or did not bracket the field residues 

for the following matrices: 

 For face/neck wipes, the fortification level (200 μg) was at least an order 

of magnitude higher than the residue levels detected in the post-exposure 

treated samples (0.446 to 25.8 μg). 

 For inner dosimeters, the low fortification level (200 μg) was within the 

range of the treated samples (1.53 to 1,439 μg), but the high fortification 

level (20,000 μg) was an order of magnitude higher than the residue 

levels. 

 For air filters, the fortification level (25 μg) was higher than the residue 

levels detected in the treated samples (0.083 to 1.61 μg). 

 Profenofos residues were detected in handwash and face/neck wipe sample collected 

prior to the exposure event. No explanation was provided for the presence of these 

residues. The study subtracted these residues out from the post-exposure samples. 

 Profenofos residues were detected in dermal and inhalation field blank residues (up to 

34xLOQ). The study states that residues were probably detected due to the proximity of 

the sample preparation area to the field being sprayed. 

 For the face/neck wipe samples at Site 1 (Cheraw, SC) and 2 on 1DAT6, it appears that 

Page 33 of 95 Page 33 of 95
Page 34 of 56 

the study did not assign the correct worker activity to some of the samples. EPA used the 

worker activity assigned to the replicate for the other matrices. 

The following concerns were noted with respect to the DFR study (Series 875.2100 Guidelines): 

 Only duplicate DFR samples were collected at each interval. The guidelines recommend 

the collection of triplicate DFR samples. 

 Two field fortification levels were used (200 μg and 20,000 μg), as recommended in the 

EPA guidelines. The low fortification level was within range of the treated samples (0.80 

to 1,434 μg), but the high fortification level was significantly higher than the treated 

samples. 

 The EPA guidelines recommend a sample surface are of 400 cm2

. In this study the total 

leaf surface was only 250 cm2, as reported in the main text of the study. It should also be 

noted that the study actually used a surface area of 227 cm2 to calculate DFRs, based on a 

punch diameter of 1.7 cm. The Rabbit Tool website (the manufacturer of Birkestrand 

punches) states that the 2.5 cm2 punch has a diameter of 1.784 cm2

, thus it appears that 

the surface area of 227 cm2 is incorrect. 

 

Page 34 of 95 Page 34 of 95
Page 35 of 56 

Table 14. Profenofos DFR Residues from Cotton Foliage Treated with Curacron® 8E – Site 1 (Cheraw, SC) 1

Sampling 

Interval 

(days) 

Measured 

Residue 

(μg) 

DFR 

(μg/cm2) 

Corrected 

Residue 

Level 3

(μg/cm2) 

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application 

Rate 

Dislodgeable4

Pre App 1 1 0.004 0.00 0.00 0.002 62.6 -5.92 -- <LOQ2 <0.003 0.0015 

0DAT1 242 0.97 0.90 0.85 0.079 9.3 -0.16 6.3 212 0.85 0.79 

0DAT2 764 3.06 2.86 2.57 0.407 15.9 0.94 18.6 610 2.44 2.28 

Pre App 3 5.0 0.020 0.019 0.018 0.002 12.30 -4.02 0.13 4.2 0.017 0.016 

0DAT3 598 2.39 2.24 2.19 0.058 2.7 0.79 16.6 576 2.30 2.15 

0DAT4 446 1.78 1.67 1.56 0.159 10.2 0.44 14.0 386 1.544 1.44 

0DAT5 900 3.60 3.36 2.83 0.761 26.9 1.04 26.5 612 2.45 2.29 

Pre App 6 5.0 0.020 0.019 0.029 0.013 45.9 -3.55 0.27 9.8 0.039 0.038 

0DAT6 424 1.70 1.59 1.74 0.217 12.5 0.55 16.3 506 2.02 1.89 

1DAT6 82.4 0.330 0.308 0.403 0.134 33.2 -0.91 3.8 133 0.532 0.497 

2DAT6 47 0.188 0.176 0.212 0.051 24.2 -1.55 2.0 66.4 0.266 0.248 

3DAT6 14.2 0.0568 0.0551 0.0559 0.001 2.0 -2.88 0.53 14.6 0.0584 0.0567 

7DAT6 6.6 0.0264 0.026 0.026 0.001 2.1 -3.65 0.24 6.8 0.0272 0.026 

14DAT6 2.6 0.0104 0.0101 0.0097 0.001 5.7 -4.63 0.09 2.4 0.0096 0.0093 

21DAT6 2 0.0080 0.0078 0.0089 0.002 18.4 -4.72 0.08 2.6 0.0104 0.0101 

28DAT6 2.2 0.0088 0.0085 0.0078 0.001 14.1 -4.86 0.07 1.8 0.0072 0.0070 

35DAT6 1.4 0.0056 0.0054 0.0047 0.001 23.6 -5.37 0.04 1.0 0.0040 0.0039 

1. Six applications were made at a target rate of 1 lb ai/A/application (11.21 μg/cm2). The actual application rate at the sixth application 

was 0.95 lb ai/A (10.6 μg/cm2

). 

2. LOQ = 0.003 μg/cm2

. Residues <LOQ were assigned a value of 1⁄2 LOQ for calculation purposes. 

3. Residues were corrected for average field fortification recoveries. Residues <40.4 μg/cm2

 were corrected for 103% recovery. 

Residues >40.4 μg/cm2 were corrected for 107%. 

4. Percent of Original Application Rate Dislodgeable = DFR (μg/cm2

) / Actual Amount applied (μg/cm2) x 100%. 

 

Page 35 of 95 Page 35 of 95
Page 36 of 56 

Table 15. Profenofos DFR Residues from Cotton Foliage Treated with Curacron® 8E – Site 2 (McFarlan, NC) 1

Sampling 

Interval 

(days) 

Measured 

Residue (μg) DFR (μg/cm2) 

Corrected 

Residue 

Level 3

(μg/cm2) 

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application 

Rate 

Dislodgeable4

Pre App 1 <LOQ2 <0.003 0.0015 0.00150 0.000 0.000 -6.50 -- <LOQ <0.003 0.0015 

0DAT1 506 2.02 1.93 1.84 0.124 6.7 0.61 15.1 460 1.84 1.75 

0DAT2 660 2.64 2.51 3.99 2.08 52.3 1.38 29.7 1434 5.74 5.46 

Pre App 3 4.6 0.018 0.016 0.014 0.004 30 -4.30 0.10 3.0 0.012 0.011 

0DAT3 562 2.25 2.14 1.98 0.221 11.1 0.69 15.0 480 1.92 1.83 

0DAT4 1050 4.20 4.00 3.95 0.065 1.6 1.37 35.6 1026 4.10 3.91 

0DAT5 444 1.78 1.69 1.48 0.302 20.4 0.39 13.3 332 1.33 1.26 

Pre App 6 7.2 0.029 0.026 0.026 0.001 1.9 -3.65 0.23 7.4 0.030 0.026 

0DAT6 468 1.87 1.78 1.82 0.054 3.0 0.60 17.1 488 1.95 1.86 

1DAT6 72.2 0.289 0.275 0.251 0.034 13.8 -1.38 

 2.4 59.4 0.238 0.226 

2DAT6 16.6 0.0664 0.0593 0.0539 0.008 14.0 -2.92 0.51 13.6 0.0544 0.0486 

3DAT6 10.4 0.042 0.037 0.038 0.002 4.0 -3.26 0.36 11 0.044 0.039 

7DAT6 6.8 0.027 0.024 0.021 0.005 21.6 -3.86 0.20 5 0.020 0.018 

14DAT6 2.2 0.0088 0.0079 0.0089 0.002 17.0 -4.72 0.08 2.8 0.011 0.0100 

21DAT6 2.2 0.0088 0.0079 0.010 0.004 34.1 -4.57 0.10 3.6 0.014 0.0129 

28DAT6 1.4 0.0056 0.0050 0.0050 0.000 0.0 -5.30 0.05 1.4 0.0056 0.0050 

35DAT6 1.2 0.0048 0.0043 0.0046 0.001 10.9 -5.37 0.04 1.4 0.0056 0.0050 

1.Six applications were made at a target rate of 1 lb ai/A/application (11.21 μg/cm2). The actual application rate at the sixth application 

was 0.95 lb ai/A (10.6 μg/cm2

). 

2.LOQ = 0.003 μg/cm2. Residues <LOQ were assigned a value of 1⁄2 LOQ for calculation purposes. 

3.Residues were corrected for average field fortification recoveries. Residues <40.4 μg/cm2 were corrected for 112% recovery. 

Residues >40.4 μg/cm2 were corrected for 105%. 

4.Percent of Original Application Rate Dislodgeable = DFR (μg/cm2) / Actual Amount applied (μg/cm2) x 100%. 

 

Page 36 of 95 Page 36 of 95
Page 37 of 56 

Table 16. Profenofos DFR Residues from Cotton Foliage Treated with Curacron® 8E – Site 3 (Chesterfield, SC) 1

Sampling 

Interval 

(days) 

Measured 

Residue (μg) DFR (μg/cm2) 

Corrected 

Residue 

Level 3

(μg/cm2) 

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application 

Rate 

Dislodgeable4

Pre 1 <LOQ2 <0.003 0.0015 0.00150 0.000 0.000 -6.50 -- <LOQ <0.003 0.0015 

0DAT1 384 1.54 1.61 1.44 0.244 16.9 0.37 11.5 302 1.21 1.27 

0DAT2 756 3.02 3.18 2.78 0.559 20.1 1.02 22.2 568 2.27 2.39 

Pre 3 7.4 0.030 0.034 0.050 0.022 43.6 -3.00 0.40 14 0.056 0.065 

0DAT3 816 3.26 3.43 3.06 0.517 16.9 1.12 22.8 642 2.57 2.70 

0DAT4 1114 4.46 4.68 4.36 0.458 10.5 1.47 32.9 960 3.84 4.03 

0DAT5 1156 4.62 4.86 5.19 0.475 9.2 1.65 44.5 1316 5.26 5.53 

Pre App 6 13.2 0.053 0.061 0.068 0.009 13.6 -2.69 0.58 16 0.064 0.074 

0DAT6 444 1.78 1.87 2.48 0.868 35.0 0.91 23.3 736 2.94 3.09 

1DAT6 362 1.45 1.52 1.54 0.024 1.5 0.43 14.4 370 1.48 1.55 

2DAT6 42.6 0.17 0.179 0.179 0.001 0.3 -1.72 1.7 42.4 0.17 0.178 

3DAT6 15.2 0.0608 0.070 0.072 0.002 2.7 -2.63 0.67 15.8 0.0632 0.073 

7DAT6 2.0 0.0080 0.0093 0.010 0.001 12.9 -4.59 0.10 2.4 0.0096 0.011 

14DAT6 2.2 0.0088 0.0102 0.0125 0.003 26.2 -4.38 0.12 3.2 0.013 0.0148 

21DAT6 1.2 0.0048 0.0056 0.0056 0.000 0.0 -5.19 0.05 1.2 0.0048 0.0056 

28DAT6 1.2 0.0048 0.0056 0.0060 0.001 10.9 -5.11 0.06 1.4 0.0056 0.0065 

35DAT6 1.6 0.0064 0.0074 0.0056 0.003 47.1 -5.19 0.05 0.8 0.0032 0.0037 

1.Six applications were made at a target rate of 1 lb ai/A/application (11.21 μg/cm2). The actual application rate at the sixth application 

was 0.95 lb ai/A (10.6 μg/cm2

). 

2.LOQ = 0.003 μg/cm2. Residues <LOQ were assigned a value of 1⁄2 LOQ for calculation purposes. 

3.Residues were corrected for average field fortification recoveries. Residues <40.4 μg/cm2 were corrected for 86.3% recovery. 

Residues >40.4 μg/cm2 were corrected for 95.2%. 

4.Percent of Original Application Rate Dislodgeable = DFR (μg/cm2) / Actual Amount applied (μg/cm2) x 100%. 

 

Page 37 of 95 Page 37 of 95
Table 18. Summary of Transfer Coefficient’s for Scouters on the Day of Last Treatment (0DAT6)1, 2

Site Replicate 

Transfer Coefficients3 (cm2/hr) 

Outer Dosimeter Inner Dosimeter Total 

Head4, 5 Hand5 

Arm Back 

Torso Front Torso Leg Total Outer Dosimeter Arm Back Torso Front Torso Leg Total Inner Dosimeter 

1 

1 113 134 161 2,649 3,057 25.6 10.2 11.3 42.9 90.0 12.53 90.1 2 133 218 136 1,688 2,175 28.0 10.2 13.3 48.3 100 5.89 51.7 5 68 134 165 2,380 2,747 38.0 6.14 9.79 78.9 133 3.91 41.9 

Average 104 162 154 2,239 2,660 30.6 8.85 11.4 56.7 108 7.44 61.2 

SD 33.1 48.9 15.5 496 447 6.59 2.34 1.76 19.4 22.5 4.52 25.4 

GM 101 157 154 2,199 2,633 30.1 8.62 11.4 54.7 106 6.61 58.0 

2 

1 280 91 238 2,108 2,718 49.7 3.4 12.5 33.2 98.8 11.66 104.5 2 64 6.63 69.1 1,020 1,160 15.1 1.28 3.48 14.8 34.7 3.47 32.9 5 67 48.8 50.2 909 1,075 26.1 2.71 5.94 27.6 62.4 3.13 18.3 

Average 137 48.8 119 1,346 1,651 30.3 2.46 7.30 25.2 65.3 6.09 51.9 

SD 124 42.2 103 663 925 17.7 1.07 4.65 9.46 32.2 4.83 46.2 

GM 107 30.9 93.8 1,250 1,502 27.0 2.27 6.37 23.8 59.8 5.02 39.8 

3 

1 200 147 219 1,657 2,223 188 13.0 11.2 70.6 282 5.43 39.3 2 108 121 163 1,195 1,587 82.3 13.0 10.5 76.7 182 2.21 33.4 5 88 98.4 76.7 713 976 57.4 5.58 6.54 69.1 139 1.42 26.1 

Average 132 122 153 1,188 1,595 109 10.5 9.43 72.1 201 3.02 32.9 

SD 59.4 24.1 71.8 472 623 69.1 4.28 2.53 4.05 73.8 2.13 6.6 

GM 124 121 140 1,122 1,510 96.1 9.80 9.17 72.1 193 2.57 32.4 

1. Six applications were made at a target rate of 1 lb ai/A/application. 

2. LOQ = 1 μg/sample for outer and inner dosimeters, 0.05 μg/sample for face/neck wipes, 0.00015 μg/mL (or 0.08 μg/sample for a 500 mL sample) for handwash. 

3. Transfer Coefficient (cm2/hr) = (Corrected residue (μg) / Time worked (hr)) / Average DFR on day of reentry. Refer to associated spreadsheet created by reviewer 

exposure values for each matrix. Residues were corrected for the average field fortification values shown in Tables 6-9. If two fortification levels were used, the m

levels was used as the threshold for determining which recovery to use. The time worked for each replicate was 4 hours. The average DFR on the day of reentry (0

1 (Cheraw, SC), 1.82 μg/cm2 for Site 2 (McFarlan, NC), and 2.48 μg/cm2 for Site 3 (Chesterfield, SC). 

4. Total head includes exposure to the face/neck areas and the non-face/non-neck areas of the head. Since exposure to the non-face/non-neck portions of the head was 

face/neck wipes were extrapolated to the non-face/non-neck portions of the head by applying a factor of 0.61. This factor is the ratio of the % of total body surface 

portion to the face/neck portion of the head for males and females. 

5. For Site 1 (Cheraw, SC) and 2, the head and hand exposure values were adjusted upward by a factor of 2 for method efficiency because measured exposure contrib

the range of 20 to 60% of total. This adjustment was not needed for Site 3 (Chesterfield, SC) because measured exposures were <20%. 

6. Total Dermal is the sum of inner dosimeters, hands, and head. The scenario represents a worker wearing a single layer of clothing (long pants and long shirt) and n

respirators. 

7. Potential Dermal is the sum of outer dosimeters, inner dosimeters, hands, and head. The scenario represents a worker wearing no clothing or personal protective eq
Page 39 of 56 

Table 19. Summary of Transfer Coefficient’s for Scouters on 24 hours After Last Treatment (1DAT6) 

Site Replicate 

Transfer Coefficients3 (cm2/hr) 

Outer Dosimeter Inner Dosimeter 

Total 

Head4, 5 Hand5 

Arm Back 

Torso Front Torso Leg Total Outer Dosimeter Arm Back Torso Front Torso Leg Total Inner Dosimeter 

1 

1 113 134 161 2,649 3,057 25.6 10.2 11.3 42.9 90.0 17.04 93.0 3 133 218 136 1,688 2,175 28.0 10.2 13.3 48.3 100 5.15 10.4 4 120 166 217 1635 2,138 107 19.3 12.3 170 308 5.09 30.4 

Average 170 374 442 2,201 3,188 108 21.7 15.2 131 276 9.09 44.6 

SD 160 371 444 1,571 2,538 52.3 15.8 9.44 44.4 110 6.88 43.1 

GM 120 274 318 1,861 2,594 99.2 17.6 13.4 125 259 7.65 30.8 

2 

3 132 181 204 6162 6,680 19.6 8.98 5.72 108 143 2.68 24.1 4 166 335 542 12,169 13,212 57.6 12.5 11.3 526 608 6.95 57.0 5 60.6 69.6 85.0 2125 2,341 20.4 5.11 5.05 72.6 103 0.75 9.50 

Average 120 195 277 6,819 7,411 32.5 8.88 7.37 236 285 3.46 30.20 

SD 53.9 133 237 5,054 5,472 21.7 3.72 3.45 252 281 3.18 24.35 

GM 110 162 211 5,422 5,911 28.5 8.32 6.89 160 208 2.41 23.54 

3 

3 16.7 42 37 467 563 47.8 5.21 4.18 70.9 128 2.09 10.9 

4 (excluded)9 22.8 54.6 61.5 296 435 23.5 4.42 5.61 66.3 100 2.45 4.58 

4A 5.5 7.08 87.8 65.1 166 6.37 0.760 0.654 10.4 18.2 0.17 0.47 

5 86.5 165 380 2907 3,539 46.1 16.0 36.5 615 713 1.77 5.19 

Average 36.2 71.5 168 1,146 1,423 33.5 7.33 13.8 232 287 1.34 5.52 

SD 43.9 83.2 185 1,538 1,844 23.5 7.85 19.8 333 374 1.03 5.22 

GM 20.0 36.6 107 445 691 24.1 3.99 4.64 76.8 118 0.86 2.98 

1. Six applications were made at a target rate of 1 lb ai/A/application. 

2. LOQ = 1 μg/sample for outer and inner dosimeters, 0.05 μg/sample for face/neck wipes, 0.00015 μg/mL (or 0.08 μg/sample for a 500 mL sample) for handwash. 

3. Transfer Coefficient (cm2/hr) = (Corrected residue (μg) / Time worked (hr)) / Average DFR on day of reentry. Refer to associated spreadsheet created by reviewer 

exposure values for each matrix. Residues were corrected for the average field fortification values shown in Tables 6-9. If two fortification levels were used, the m

levels was used as the threshold for determining which recovery to use. The time worked for each replicate was 4 hours. The average DFR on the day of reentry (1

1 (Cheraw, SC), 0.251 μg/cm2 for Site 2 (McFarlan, NC), and 1.54 μg/cm2 for Site 3 (Chesterfield, SC). 

4. Total head includes exposure to the face/neck areas and the non-face/non-neck areas of the head. Since exposure to the non-face/non-neck portions of the head was 

face/neck wipes were extrapolated to the non-face/non-neck portions of the head by applying a factor of 0.61. This factor is the ratio of the % of total body surface 

portion to the face/neck portion of the head for males and females. 

5. Method efficiency adjustments were not needed because measured exposure contribution from hands and head were <20% of total for all sites. 

6. Total Dermal is the sum of inner dosimeters, hands, and head. The scenario represents a worker wearing a single layer of clothing (long pants and long shirt) and n

respirators. 

7. Potential Dermal is the sum of outer dosimeters, inner dosimeters, hands, and head. The scenario represents a worker wearing no clothing or personal protective eq

8. It appears that the study incorrectly assigned the worker activity for face/neck wipe replicates at Sites 1 and 2 on 1DAT6. The reviewer assumed that the sample num

consistent between matrices. Specifically, at Site 1 (Cheraw, SC) and Site 2 (McFarlan, NC), the study assigned replicates 3 and 4 as hoers, but the reviewer assum

replicates. 

9. Replicate 4 at Site 3 (Chesterfield, SC) dropped out due to heat exhaustion, and was replaces with replicate 4A. Replicate 4 was not used in statistical summaries of t
Page 40 of 56 

Table 20. Summary of Transfer Coefficient’s for Hoers on the Day of Last Treatment (0DAT6) 

Site Replicate 

Transfer Coefficients3 (cm2/hr) 

Outer Dosimeter Inner Dosimeter 

Total 

Head4, 5 Hand

Arm Back 

Torso Front Torso Leg Total Outer Dosimeter Arm Back Torso Front Torso Leg Total Inner Dosimeter 

1 

3 62.6 107 156 254 580 25.7 1.99 7.92 4.83 40.4 1.97 49.0 

4 46.6 108 160 956 1,271 13.5 6.53 6.45 29.8 56.3 3.86 22.2 

Average 54.6 107 158 605 926 19.6 4.26 7.18 17.3 48.4 2.915 35.6 

GM 54.0 107 158 493 858 18.7 3.61 7.15 12.0 47.7 2.757 33.0 

2 

3 86.2 48.2 245 843 1,223 46.0 2.21 5.72 12.7 66.7 0.750 27.2 

4 68.8 52.7 48.5 888 1,058 13.6 2.70 5.64 36.3 58.2 1.769 39.1 

Average 77.5 50.4 147 866 1,140 29.8 2.46 5.68 24.5 62.4 1.260 33.2 

GM 77.0 50.4 109 865 1,137 25.0 2.44 5.68 21.5 62.3 1.152 32.6 

3 

3 98.3 95.8 118 1231 1,543 79.9 14.4 10.8 71.4 177 2.05 48.1 

4 81.8 87.1 89.1 958 1,216 37.0 7.96 6.91 102 154 3.58 16.1 

Average 90.0 91.5 103 1,095 1,379 58.5 11.2 8.86 86.7 165 2.82 32.1 

GM 89.7 91.4 102 1,086 1,370 54.4 10.7 8.64 85.3 165 2.71 27.8 

1. Six applications were made at a target rate of 1 lb ai/A/application. 2. LOQ = 1 μg/sample for outer and inner dosimeters, 0.05 μg/sample for face/neck wipes, 0.00015 μg/mL (or 0.08 μg/sample for a 500 mL sample) for handwash. 

3. Transfer Coefficient (cm2/hr) = (Corrected residue (μg) / Time worked (hr)) / Average DFR on day of reentry. Refer to associated spreadsheet created by reviewer 

exposure values for each matrix. Residues were corrected for the average field fortification values shown in Tables 6-9. If two fortification levels were used, the m

levels was used as the threshold for determining which recovery to use. The time worked for each replicate was 4 hours. The average DFR on the day of reentry (0

1 (Cheraw, SC), 1.82 μg/cm2 for Site 2 (McFarlan, NC), and 2.48 μg/cm2 for Site 3 (Chesterfield, SC). 

4. Total head includes exposure to the face/neck areas and the non-face/non-neck areas of the head. Since exposure to the non-face/non-neck portions of the head was 

face/neck wipes were extrapolated to the non-face/non-neck portions of the head by applying a factor of 0.61. This factor is the ratio of the % of total body surface 

portion to the face/neck portion of the head for males and females. 

5. For Site 1 (Cheraw, SC) and 2, the head and hand exposure values were adjusted upward by a factor of 2 for method efficiency because measured exposure contrib

the range of 20 to 60% of total. This adjustment was not needed for Site 3 (Chesterfield, SC) because measured exposures were <20%. 

6. Total Dermal is the sum of inner dosimeters, hands, and head. The scenario represents a worker wearing a single layer of clothing (long pants and long shirt) and n

respirators. 

7. Potential Dermal is the sum of outer dosimeters, inner dosimeters, hands, and head. The scenario represents a worker wearing no clothing or personal protective eq
Page 41 of 56 

Table 21. Summary of Transfer Coefficient’s for Hoers on 24 hours After Last Treatment (1DAT6) 

Site Replicate 

Transfer Coefficients (cm2/hr) 

Outer Dosimeter Inner Dosimeter 

Total Head Han

Arm 

Back Torso Front Torso Leg Total Outer Dosimeter Arm Back Torso Front Torso Leg Total Inner Dosimeter 

1 

2 238 404 257 933 1,833 71.3 11.4 10.8 15.0 108 6.18 102.

5 81.6 140 263 772 1,257 45.4 15.7 17.1 39.0 117 3.81 45.2 

Average 160 272 260 853 1,545 58.3 13.6 13.9 27.0 113 5.00 73.9 

GM 139 238 260 849 1,518 56.9 13.4 13.6 24.2 113 4.86 68.1 

2 

1 98.8 112 178 1379 1,767 33.8 10.5 14.4 162.7 221 4.09 32.1 

2 89.9 152 130 1118 1,490 20.9 3.53 10.8 2.58 37.8 6.03 93.7 

Average 94 132 154 1,248 1,629 27.3 7.01 12.6 82.6 130 5.06 62.9 

GM 94 130 152 1,241 1,623 26.5 6.09 12.5 20.5 91.5 4.97 54.9 

3 

1 77.0 55.2 39.2 341 513 61.9 3.69 4.91 48.7 119 0.731 4.76 

2 55.4 44.1 43.1 142 284 73.1 5.21 10.6 12.0 101 1.96 16.2 

Average 66.2 49.7 41.2 241 398 67.5 4.45 7.73 30.3 110 1.35 10.5 

GM 65.3 49.4 41.1 220 382 67.3 4.38 7.20 24.1 110 1.20 8.78 

 1. Six applications were made at a target rate of 1 lb ai/A/application. 2. LOQ = 1 μg/sample for outer and inner dosimeters, 0.05 μg/sample for face/neck wipes, 0.00015 μg/mL (or 0.08 μg/sample for a 500 mL sample) for handwash. 

3. Transfer Coefficient (cm2/hr) = (Corrected residue (μg) / Time worked (hr)) / Average DFR on day of reentry. Refer to associated spreadsheet created by reviewer 

exposure values for each matrix. Residues were corrected for the average field fortification values shown in Tables 6-9. If two fortification levels were used, the m

levels was used as the threshold for determining which recovery to use. The time worked for each replicate was 4 hours. The average DFR on the day of reentry (1

1 (Cheraw, SC), 0.251 μg/cm2 for Site 2 (McFarlan, NC), and 1.54 μg/cm2 for Site 3 (Chesterfield, SC). 

4. Total head includes exposure to the face/neck areas and the non-face/non-neck areas of the head. Since exposure to the non-face/non-neck portions of the head was 

face/neck wipes were extrapolated to the non-face/non-neck portions of the head by applying a factor of 0.61. This factor is the ratio of the % of total body surface 

portion to the face/neck portion of the head for males and females. 

5. Method efficiency adjustments were not needed because measured exposure contribution from hands and head were <20% of total for all sites. 

6. Total Dermal is the sum of inner dosimeters, hands, and head. The scenario represents a worker wearing a single layer of clothing (long pants and long shirt) and n

respirators. 

7. Potential Dermal is the sum of outer dosimeters, inner dosimeters, hands, and head. The scenario represents a worker wearing no clothing or personal protective eq8. It appears that the study incorrectly assigned the worker activity for face/neck wipe replicates at Sites 1 and 2 on 1DAT6. The reviewer assumed that the sample nu

consistent between matrices. Specifically, replicates 2 and 5 at Site 1 (Cheraw, SC) and replicates 1 and 2 at Site 2 (McFarlan, NC) were assigned as scouters, but actually hoer replicates. 
Page 42 of 56 

Table 22. Distribution (Percent) of Total Exposure 

Site Statistic Arm Back 

Torso 

Front 

Torso Leg 

Total 

Inner 

Dosimeter 

Face/Neck Hand 

Scouters on 0DAT6 

1 Average 17.5 5.1 6.6 32.4 61.5 4.14 34.4 

2 Average 25.2 2.2 5.9 23.1 56.4 4.68 38.9 

3 Average 43.2 4.4 4.1 32.8 84 1.18 14.3 

All Sites Combined Average 28.6 3.9 5.5 29.4 67.5 3.33 29.2 

Standard Deviation 13.4 1.7 1.5 10.0 16.7 2.03 14.8 

Scouters on 1DAT6 

1 Average 32.8 6.0 4.5 42.5 86 2.70 11.5 

2 Average 12.7 3.9 3.2 68.8 88.5 1.09 10.4 

3 Average 24.0 3.5 4.2 63 95.0 1.24 3.8 

All Sites Combined Average 23.3 4.4 4.0 58.7 90.3 1.63 8.1 

Standard Deviation 11.4 1.8 1.2 15.9 6.2 1.05 5.5 

Hoers on 0DAT6 

1 Average 22.3 5.0 8.2 20.7 56.3 3.42 40.3 

2 Average 31.2 2.5 5.9 25.0 64.6 1.29 34.1 

3 Average 28.3 5.5 4.4 45.1 83.3 1.48 15.2 

All Sites Combined Average 27.3 4.4 6.2 30.3 68.1 2.06 29.9 

Standard Deviation 13.1 2.4 1.8 18.9 15.4 1.41 15.3 

Hoers on 1DAT6 

1 Average 30.1 7.4 7.6 15.2 60 2.57 37.2 

2 Average 14.1 3.3 6.7 32.5 56.7 2.99 40.3 

3 Average 55.5 3.7 6.4 25 90 1.12 8.7 

All Sites Combined Average 33.2 4.8 6.9 24 69 2.22 28.7 

Standard Deviation 19.1 2.5 2.5 23.4 25.8 1.30 24.5 

Table 23. Penetration (Percent) from Outer to Inner Dosimeter 

Site Statistic Arm Back 

Torso 

Front 

Torso Leg Average 

Scouters on 0DAT6

1 Average 23.9 5.3 7.0 2.5 9.7 

2 Average 23.9 5.3 7.0 2.5 9.5 

3 Average 42.6 7.6 6.6 6.9 15.9 

All Sites Combined Average 29.1 7.1 6.8 3.8 11.7 

Standard Deviation 12.0 3.9 1.9 2.5 3.7 

Scouters on 1DAT6

1 Average 45.5 6.5 4.2 6.8 15.8 

2 Average 45.5 6.5 4.2 6.8 8.2 

3 Average 54.1 9.9 6.5 14.8 21.3 

All Sites Combined Average 40.3 7.1 4.7 8.2 15.1 

Standard Deviation 19.2 2.9 3.1 5.6 6.8 

Hoers on 0DAT6

1 Average 25.8 3.8 4.3 2.4 9.1 

2 Average 25.8 3.8 4.3 2.4 9.8 

3 Average 38.0 10.7 7.8 7.5 16.0 

All Sites Combined Average 29.8 6.4 6.2 4.2 11.7 

Standard Deviation 9.8 3.9 3.1 3.0 3.7 

Hoers on 1DAT6

1 Average 29.4 6.4 5.1 3.2 11.0 

2 Average 29.4 6.4 5.1 3.2 10.1 

3 Average 50.7 8.4 15.4 10.1 21.2 

All Sites Combined Average 34.1 6.7 9.3 6.2 14.1 

Standard Deviation 14.6 3.6 5.6 4.9 6.3 

Page 42 of 95 Page 42 of 95
Page 43 of 56 

Table 24. Inhalation Exposure (μg /hr) for Scouters Based on Residue Levels Found on Pre-loaded Filter Cassettes and Air Sam

Site Replicate 

Filter Residues Air Sorbent Tube Residues Total Corrected Air 

Residues4

(μg) 

Actual 

Sample 

Volume5

(L) 

Air Conc.6

(μg/m3) 

Vent. 

Rate7

(m3/min) 

Inha

Measured 

(μg) 

Corrected3

(μg) 

Measured 

(μg) 

Corrected3

(μg) Per repl

0DAT6 

1 

1 1.61 1.68 <0.1 0.050 1.73 262.28 6.60 0.0167 6.60 

2 1.12 1.17 <0.1 0.050 1.22 256.90 4.75 0.0167 4.75 5 1.12 1.17 <0.1 0.050 1.22 239.40 5.09 0.0167 5.09 

2 

1 1.35 1.39 <0.1 0.050 1.44 248.30 5.79 0.0167 5.79 

2 0.777 0.799 <0.1 0.050 0.849 244.40 3.48 0.0167 3.48 5 0.483 0.497 <0.1 0.050 0.547 155.70 3.51 0.0167 3.51 

3 

1 1.32 1.63 <0.1 0.050 1.68 253.75 6.62 0.0167 6.62 

2 1.26 1.56 <0.1 0.050 1.61 227.24 7.07 0.0167 7.07 5 0.731 0.902 <0.1 0.050 0.952 251.74 3.78 0.0167 3.78 

1DAT6 

1 

1 0.408 0.580 <0.1 0.050 0.630 257.85 2.44 0.0167 2.44 

3 0.328 0.466 <0.1 0.050 0.516 259.35 1.99 0.0167 1.99 4 0.270 0.384 <0.1 0.050 0.434 251.90 1.72 0.0167 1.72 

2 

3 0.317 0.362 <0.1 0.050 0.412 274.40 1.50 0.0167 1.50 

4 0.426 0.486 <0.1 0.050 0.536 277.20 1.93 0.0167 1.93 5 0.195 0.223 <0.1 0.050 0.273 245.00 1.11 0.0167 1.11 

3 

3 0.359 0.355 <0.1 0.050 0.405 295.00 1.37 0.0167 1.37 

49 0.092 0.091 <0.1 0.050 0.141 100.50 1.40 0.0167 1.40 4A 0.083 0.082 <0.1 0.050 0.132 241.00 0.548 0.0167 0.55 

5 0.262 0.259 <0.1 0.050 0.309 338.80 0.913 0.0167 0.91 

1. Six applications were made at a target rate of 1 lb ai/A/application. 2. LOQ = 0.1 μg. Residues <LOQ were assigned a value of 1⁄2 LOQ for calculation purposes. 

3. 0DAT6: Site 1 (Cheraw, SC), 2, and 3 residues from the pre-loaded filter cassettes were corrected for average field fortification recoveries of 95.8%, 97.2%, 

1DAT6: Site 1 (Cheraw, SC), 2, and 3 residues from the pre-loaded filter cassettes were corrected for average field fortification recoveries of 70.4%, 87.6%, 

Corrected Air Residues (μg) = corrected pre-loaded filter cassettes (μg) + corrected air sampling tube residues (μg) 

4. The actual air sample volume was reported, but actual air flow rates and durations were not reported. The nominal air flow rate was 1 L/min. The nominal du

5. Concentration (μg/m3) = Residue (μg)/[Flow rate (L/min) x Duration (min)] x 1000 (L/m3) 

6. The NAFTA ventilation rate is for light activities. 7. Inhalation Exposure (μg/hr) = Concentration (μg/m3) x Ventilation Rate (0.0167 m3/min) x 60 minutes/hr 

8. Replicate 4 at Site 3 (Chesterfield, SC) dropped out due to heat exhaustion, and was replaces with replicate 4A. Replicate 4 was not used in statistical summ
Page 44 of 56 

Table 25. Inhalation Exposure (μg /hr) for Hoers Based on Residue Levels Found on Pre-loaded Filter Cassettes and Air Samp

Site Replicate 

Filter Residues Air Sorbent Tube Residues Total 

Corrected Air 

Residues4 (μg)

Actual 

Sample 

Volume5 (L) 

Air Conc.6

(μg/m3) 

Vent. Rate7

(m3/min) 

I

Measured 

(μg) 

Corrected3

(μg) 

Measured 

(μg) 

Corrected3

(μg) P

0DAT6 

1 3 1.14 1.19 <0.1 0.050 1.24 240.56 5.15 0.0267 

4 0.912 0.952 <0.1 0.050 1.00 239.32 4.19 0.0267 

2 3 0.901 0.927 <0.1 0.050 0.977 242.57 4.03 0.0267 

4 0.879 0.904 <0.1 0.050 0.954 252.73 3.78 0.0267 

3 3 1.03 1.27 <0.1 0.050 1.32 242.59 5.45 0.0267 

4 0.952 1.18 <0.1 0.050 1.23 282.15 4.34 0.0267 

1DAT6 

1 2 0.341 0.484 <0.1 0.050 0.534 260.72 2.05 0.0267 

5 0.232 0.330 <0.1 0.050 0.380 248.43 1.53 0.0267 

2 1 0.268 0.306 <0.1 0.050 0.356 279.39 1.27 0.0267 

2 0.309 0.353 <0.1 0.050 0.403 269.66 1.49 0.0267 

3 1 0.301 0.298 <0.1 0.050 0.348 267.00 1.30 0.0267 

2 0.401 0.397 <0.1 0.050 0.447 289.08 1.55 0.0267 

1. Six applications were made at a target rate of 1 lb ai/A/application. 2. LOQ = 0.1 μg. Residues <LOQ were assigned a value of 1⁄2 LOQ for calculation purposes. 3. 0DAT6: Site 1 (Cheraw, SC), 2, and 3 residues from the pre-loaded filter cassettes were corrected for average field fortification recoveries of 95.8%, 97.2%, and 8

1 (Cheraw, SC), 2, and 3 residues from the pre-loaded filter cassettes were corrected for average field fortification recoveries of 70.4%, 87.6%, and 101%, respectiv

4. Total Corrected Air Residues (μg) = corrected pre-loaded filter cassettes (μg) + corrected air sampling tube residues (μg) 5. The actual air sample volume was reported, but actual air flow rates and durations were not reported. The nominal air flow rate was 1 L/min. The nominal duratio

6. Concentration (μg/m3) = Residue (μg)/Sample volume (L) * 1000 L/m3

7. The NAFTA ventilation rate is for light activities. 8. Inhalation Exposure (μg/hr) = Concentration (μg/m3) x Ventilation Rate (0.0167 m3/min) x 60 minutes/hr 
Page 45 of 56 

Table 26. Profenofos Residues from Cotton Bolls Treated with Curacron® 8E1,2 

Site 

Sampling 

Interval 

(days) 

Matrix 

Measured 

Residue 

(μg) 

Dislodgeable 

Residue3 

Corrected 

Dislodgeable 

Residue4 

Arithmetic Mean 

Percent of 

Application 

Rate 

(ug/g) (μg/cm Dislodgeable 2) (ug/g) (μg/cm2) (ug/g) (μg/cm2) 

1 

35 Boll + 

carpel 

1.25 NA 0.0021 NA 0.0019 NA 0.0021 0.019 1.5 0.0026 0.0023 

61 Boll 

only 

<0.75 0.52 0.0015 0.26 0.00075 0.26 0.0007 0.007 <0.75 0.52 0.0015 0.26 0.00075 

2 

38 Boll + 

carpel 

1.75 NA 0.0030 NA 0.0025 NA 0.0025 0.023 1.75 0.0030 0.0025 

44 Boll 

only 

<0.75 0.52 0.0015 0.26 0.00075 0.26 0.0007 0.007 <0.75 0.52 0.0015 0.26 0.00075 

3 

36 Boll + 

carpel 

1.25 NA 0.0021 NA 0.0024 NA 0.0015 0.013 <0.75 0.0013 0.00064 

70 Boll 

only 

<0.75 0.52 0.0015 0.26 0.00075 0.26 0.0007 0.007 <0.75 0.52 0.0015 0.26 0.00075 

1. Six applications were made at a target rate of 1 lb ai/A/application (11.21 μg/cm2). 

2. LOQ = 0.75 μg. Residues <LOQ were assigned a value of 1⁄2 LOQ for calculation purposes. 

3. Dislodgeable Residue (ug/g) = Measured residue (ug) / Mean cotton boll weight (g). The mean cotton boll weight was determined to be 

1.44 g. Dislodgeable Residue (μg/cm2

) = Measured residue (μg) / Surface Area of Sample (cm2). The surface areas were determined to be 

586 cm2

 for boll + carpel and 503 cm2 for boll only. 

4. Residues were corrected for the low level average field fortification recovery for boll+carpel or boll only, specifically. The Site 1 (Cheraw, 

SC), 2, and 3 boll +carpel residues were corrected for recoveries of 112, 118, and 90.5% recovery, respectively. No other samples required 

correction because residues <LOQ were not corrected. 

5. Percent of Original Application Rate Dislodgeable = Dislodgeble residue (μg/cm2

) / Amount applied (μg/cm2) x 100%. 

 

Page 45 of 95 Page 45 of 95
Page 46 of 56 

Appendix A. First Order Kinetics Regression 

Study Summary for Site 1 

MRID 42851302 

Crop Cotton 

Region/State 

 2/ Cheraw, 

SC 

Application 

Rate (lb 

ai/acre) 0.95 

 

Dislodgeable Foliar Residue (DFR) Analysis EPA/OPP/HED 1st Order Kinetics Re-entry 

Day 

(Day After 

Treatment) 

Measured DFR (ug/cm2) 

Individual 

Samples Average Standard Deviation DAT ln(DFR) 

Modeled (ln 

DFR) 

Modeled 

DFR 

0 

1.585 

1.7383 0.2168 

 0 0.553 -1.452 0.234 

1.892 1 -0.910 -1.587 0.205 

 2 -1.551 -1.721 0.179 

1 

0.308 

0.4026 0.1338 

 3 -2.884 -1.856 0.156 

0.497 7 -3.649 -2.395 0.091 

 14 -4.635 -3.338 0.036 

2 

0.176 

0.2120 0.0513 

 21 -4.718 -4.281 0.014 

0.248 28 -4.858 -5.224 0.005 

 35 -5.369 -6.167 0.002 

3 

0.055 

0.0559 0.0011 

 

0.057 

 

Residue 

Dissipation 

Decay constant

(k) -0.135 

7 

0.026 

0.0260 0.0005 

Daily 

Dissipation (%) 13% 

0.026 Half-life (days) 5.1 

 

Initial Residue 

C0 (ug/cm2) 0.234 

14 

0.0101 

0.0097 0.0005 

% of 

application rate 2.20% 

0.0093 

 

21 

0.0078 

0.0089 0.0016 

 

0.0101 

 

28 

0.0085 

0.0078 0.0011 

 

0.0070 

 

35 

0.0054 

0.0047 0.0011 

 

0.0039 

 

Page 46 of 95 Page 46 of 95
Page 47 of 56 

 

y = -0.1347x - 1.4519

R2 = 0.7132

-7.000

-6.000

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

0 5 10 15 20 25 30 35 40

ln DFR (ug/cm2)

DAT

Cheraw, SC Data

ln DFR vs. DAT

Page 47 of 95 Page 47 of 95
Page 48 of 56 

Study Summary for Site 2 

MRID 42851302 

Crop Cotton 

Region/State 

 2/McFarlan, 

NC 

Application 

Rate (lb ai/acre) 0.95 

 

Dislodgeable Foliar Residue (DFR) Analysis EPA/OPP/HED 1st Order Kinetics 

Re-entry Day 

(Day After 

Treatment) 

Measured DFR (ug/cm2) 

Individual 

Samples Average Standard Deviation DAT ln(DFR) 

Modeled (ln 

DFR) 

Modeled 

DFR 

0 

1.783 

1.8210 0.0539 

 0 0.599 -1.923 0.146 

1.859 1 -1.384 -2.045 0.129 

 2 -2.920 -2.166 0.115 

1 

0.275 

0.2507 0.0345 

 3 -3.265 -2.287 0.102 

0.226 7 -3.860 -2.773 0.062 

 14 -4.718 -3.623 0.027 

2 

0.059 

0.0539 0.0076 

 21 -4.570 -4.473 0.011 

0.049 28 -5.298 -5.324 0.005 

 35 -5.372 -6.174 0.002 

3 

0.037 

0.0382 0.0015 

 

0.039 

 

Residue 

Dissipation 

Decay constant

(k) -0.121 

7 

0.024 

0.0211 0.0045 

Daily 

Dissipation 

(%) 11% 

0.018 Half-life (days) 5.7 

 

Initial Residue 

C0 (ug/cm2) 0.146 

14 

0.0079 

0.0089 0.0015 

% of 

application 

rate 1.37% 

0.0100 

 

21 

0.0079 

0.0104 0.0035 

 

0.0129 

 

28 

0.0050 

0.0050 0.0000 

 

0.0050 

 

35 

0.0043 

0.0046 0.0005 

 

0.0050 

 

Page 48 of 95 Page 48 of 95
Page 49 of 56 

 

y = -0.1214x - 1.9231

R2 = 0.6351

-7.000

-6.000

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

0 5 10 15 20 25 30 35 40

ln DFR (ug/cm2)

DAT

McFarlan, NC Data

ln DFR vs. DAT

Page 49 of 95 Page 49 of 95
Page 50 of 56 

Study Summary for Site 3 

MRID 42851302 

Crop Cotton 

Region/State 

2/Chesterfield, 

SC 

Application Rate 

(lb ai/acre) 0.95 

 

Dislodgeable Foliar Residue (DFR) Analysis EPA/OPP/HED 1st Order Kinetics Re-entry Day 

(Day After 

Treatment) 

Measured DFR (ug/cm2) 

Individual 

Samples Average Standard Deviation DAT Ln (DFR) Modeled (ln DFR) Modeled DFR 

0 

1.8655 

2.4790 0.8675 

 0 0.908 -1.219 0.296 

3.0924 1 0.430 -1.368 0.255 

 2 -1.723 -1.516 0.219 

1 

1.5210 

1.5378 0.0238 

 3 -2.633 -1.665 0.189 

1.5546 7 -4.586 -2.260 0.104 

 14 -4.381 -3.301 0.037 

2 

0.1790 

0.1786 0.0006 

 21 -5.192 -4.342 0.013 

0.1782 28 -5.112 -5.383 0.005 

 35 -5.192 -6.425 0.002 

3 

0.0705 

0.0718 0.0020 

 

0.0732 

 

Residue 

Dissipation 

Decay constant

(k) -0.149 

7 

0.0093 

0.0102 0.0013 

Daily Dissipation 

(%) 14% 

0.0111 Half-life (days) 4.7 

 

Initial Residue C0 (ug/cm2) 0.296 

14 

0.0102 

0.0125 0.0033 

% of application 

rate 2.77% 

0.0148 

 

21 

0.0056 

0.0056 0.0000 

 

0.0056 

 

28 

0.0056 

0.0060 0.0007 

 

0.0065 

 

35 

0.0074 

0.0056 0.0026 

 

0.0037 

 

Page 50 of 95 Page 50 of 95
Page 51 of 56 

 

y = -0.1487x - 1.2189

R2 = 0.6271

-7.000

-6.000

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

2.000

0 5 10 15 20 25 30 35 40

ln DFR (ug/cm2)

DAT

Chesterfield, SC Data

ln DFR vs. DAT

Page 51 of 95 Page 51 of 95
Page 52 of 56 

Appendix B. Biphasic (“Hockey Stick”) Regression 

Site 1. Cheraw, SC 

"Hockey Stick" 

(untransformed residuals) 

Modeled DFR Squared Residuals 

1.73 0.02

1.73 0.03

0.46 0.02

0.46 0.00

0.09 0.01

0.09 0.02

0.02 0.00

0.02 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

Sum of Squared Errors (SSE) 0.11

C0 (ug/cm2) 2.3

C0: % of application rate 21%

Decay constant 1 (k1) -1.587

Decay constant 2 (k2) -1.587

Inflection Point (day) 12

Page 52 of 95 Page 52 of 95
Page 53 of 56 

 

0.000

0.500

1.000

1.500

2.000

2.500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851302 - Cheraw, SC_profenofos

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 53 of 95 Page 53 of 95
Page 54 of 56 

Site 2. Chesterfield, SC 

"Hockey Stick" 

(untransformed residuals) 

Modeled DFR Squared Residuals 

2.57 0.50

2.57 0.27

1.20 0.10

1.20 0.12

0.48 0.09

0.48 0.09

0.19 0.02

0.19 0.01

0.01 0.00

0.01 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

Sum of Squared Errors (SSE) 1.21

C0 (ug/cm2) 3.0

C0: % of application rate 28%

Decay constant 1 (k1) -0.912

Decay constant 2 (k2) -1.588

Inflection Point (day) 12

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851302_profenofos_Chesterfield, SC

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 54 of 95 Page 54 of 95
Page 55 of 56 

 

Page 55 of 95 Page 55 of 95
Page 56 of 56 

Site 3. McFarlan, NC 

"Hockey Stick" 

(untransformed residuals) 

Modeled DFR Squared Residuals 

1.82 0.00

1.82 0.00

0.26 0.00

0.26 0.00

0.02 0.00

0.02 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

Sum of Squared Errors (SSE) 0.01

C0 (ug/cm2) 2.7

C0: % of application rate 25%

Decay constant 1 (k1) -2.345

Decay constant 2 (k2) -1.588

Inflection Point (day) 12

0.000

0.500

1.000

1.500

2.000

2.500

3.000

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851302_profenofos_McFarlan, NC

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 56 of 95 Page 56 of 95
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

DATE: 15-SEP-15 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Profenofos: Review of "Dissipation of Dislodgeable Foliar Residues of 

Profenofos (Curacron ® 8E) Applied to Cotton in California" 

PC Code: 111401 

Decision Number: 482022 

Petition Number: NA 

Risk Assessment Type: NA 

TXR Number: NA 

MRID Numbers: 42851303 

DP Barcode: 0429108 

Registration Number: NIA 

Regulatory Action: NIA 

Case Number: 2540 

CAS Number: 41198-08-7 

40CFR: §180.404 

FROM: 

Risk 

Health 

Kelly 

Assessment 

Lowe, 

Effects 

Environmental 

Division 

Branch 

(HED)

I (RAB 

Scientist 

, 7509P 

1) 

~ 

THROUGH: Thurston Morton, Acting Branch Chief 

RABI I HED, 7509P 

TO: Christina Scheltema 

Patricia Parrott 

Pesticide Re-Evaluation Division (PRD) (7508P) 

ACTION REQUESTED: 

The Registration Division (RD) requested that the Health Effects Division (HED) conduct a 

review of the submitted dislodgeable foliar residue study for profenofos. 

SUMMARY OF STUDY RESULTS: 

This study was designed to determine the dissipation of dislodgeable foliar residues (DFRs) of 

the active ingredient (ai) profenofos from treated cotton foliage. The test product was a 73% ai 

emulsifiable concentrate (EC) formulation. One test site was examined in Madera, CA (NAFT A 

Region 10) during the 1991 growing season. Geographical and climatic conditions were relevant 

to the use pattern proposed. The trial site consisted of one control plot and one treatment plot, 

with the treatment plot receiving six foliar broadcast spray applications of the test substance via 

Page I of 19 

Page 57 of 95
Page 2 of 19 

tractor-mounted groundboom sprayers at a nominal rate of 1.0 lb ai/A/application. Applications 

were made using a spray volume of approximately 30 gallons per acre, at retreatment intervals of 

5-6 days. 

 

Single control plot and triplicate treated plot DFR samples were collected using a Birkestrand 

leaf punch sampler prior to and after the first, third, and sixth (last) application, and at the 

following intervals after the last application: 1, 2, 3, 7, 14, 21, 28, and 35 days. EPA calculated 

DFRs in μg/cm2, correcting for field fortification recoveries and a leaf surface area of 400 cm2. 

The highest average DFR was 1.66 μg/cm2, which occurred immediately after the first 

application (14.8% of application rate). The average DFR immediately prior to the last (sixth) 

application was 0.120 μg/cm2. The maximum average DFR after the last application occurred at 

the first sampling interval (after spray dried) with a value of 1.38 μg/cm2 (12.3% of application 

rate). DFRs declined rapidly in the first three days to 0.162 μg/cm2 (1.4% of application rate) at 

3DAT6, and reached equilibrium at 21DAT6 with a value of 0.010 μg/cm2 (0.09% of 

application rate). DFRs on 28DAT6 and 35DAT6 were 0.011 and 0.0081 μg/cm2, respectively. 

 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos. The Registrant conducted linear regression analyses using the natural logarithm of 

average DFR values from the following sampling intervals: 1) 0DAT6 through 35DAT6 (all 

sampling intervals after the last application), 2) 0DAT6 though 21DAT6 (sampling intervals 

through the point of equilibrium), 3) 0DAT6 through 3DAT6 (first part of bi-phasic pattern), and 

4) 3DAT6 through 35DAT6 (second part of bi-phasic pattern). The Registrant’s calculated halflives for these intervals, respectively, were 5.4 days (R2

 = 0.816), 3.4 days (R2 = 0.881), 1.0 days 

(R2 = 0.942), and 7.9 days (R2 = 0.848). Additionally, the Registrant generated a decline curve fit 

using an equation representing the data specifically (y=a+bexp-x), as determined by Table Curve 

Fitting Software. The half-life calculated was 0.7 days (R2 = 0.993). 

EPA first assumed first-order dissipation kinetics and conducted a linear regression analysis 

using the corrected average DFRs from immediately after the last application (0DAT6) through 

the last sampling interval (35DAT6), and determined a half-life of 5.4 days (R2 = 0.8212). 

However, the regression analysis did not appear visually to be a good fit for the data, and a 

comparison of the 0DAT6 actual and predicted DFRs show that the actual DFR (1.38 μg/cm2) is 

~4x higher than the linear regression predicted DFR (0.3357 μg/cm2

). Therefore, EPA did 

additional analysis and conducted a biphasic (“hockey stick”) regression analysis using Excel’s 

Solver, and the corrected average DFRs from immediately after the last application through the 

last sampling interval. This regression analysis appears (visually) to be a better fit of the data, 

and provides a predicted Day 0 value of 1.74 μg/cm2

. 

CONCLUSIONS:

No major issues were identified during review of this study and the results are considered 

acceptable for risk assessment purposes. 

No major issues were identified during review of this study and the results are considered 

acceptable for risk assessment purposes. There were some issues noted regarding the field 

fortification recovery samples: (1) only one field fortification level was used in the study, and the 

Page 58 of 95 Page 58 of 95
Page 3 of 19 

EPA guideline recommends a minimum of two field fortification levels; (2) the level chosen was 

below most of the field samples (10 ug/sample for the field fortification samples vs a maximum 

of 648 ug/sample for the field samples); and (3) several recoveries were outside the guideline 

range of 70-120%. However, the study report did provide additional information with respect to 

laboratory recovery samples, which included concentrations up to 1000 ug/sample, with 

recoveries ranging from 88 – 121%; therefore, it is unlikely that the field fortification issues 

would impact the utility of the study for risk assessment. 

Summary of DFR Values and Regression Analysis Results for Treated Cotton with Profenofos (MRID# 

42851303). 

Cotton; Site: Madera, CA 

Study Target Rate (lb ai/A) 1.00 lb ai/A 

Spray Volume (GPA) 30 

Measured Average Day 0 Residue (μg/cm2) 0DAT6: 1.38 

Linear Regression Predicted Day 0 Residue (μg/cm2) 0DAT6: 0.336 

Slope -0.129 

Half-life (days) 5.4 

R2 0.8212 

Biphasic Regression Predicted Day 0 Residue (ug/cm2) 0DAT6: 1.74 

Slope -1.345, -0.251 

0

0.5

1

1.5

2

2.5

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851303_profenofos_CA

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 59 of 95 Page 59 of 95
Page 4 of 19 

DATA EVALUATION RECORD

STUDY TYPE: Determination of Dislodgeable Foliar Residues on Cotton Treated with 

Profenofos; OCSPP 875.2100 

PC CODE: 111401 

TEST MATERIAL Curacron® 8E, an emulsifiable concentrate (EC) formulation containing 

73% of active ingredient (ai) profenofos (8 lb ai/gal) 

SYNONYMS: Common name: Profenofos 

Formulation Trade name: Curacron® 8E 

Chemical name: 0-(4-bromo-2-chlorphenyl) 0-ethyl S-propyl 

phosphorothioate 

CAS No.: 41198-08-7 

CITATION: Author: Michael E. Miller 

 Title: Dissipation of Dislodgeable Foliar Residues 

of Profenofos (Curacron ® 8E) Applied to 

Cotton in California 

Report Date: February 4, 1993 

Field Research Laboratory: Pan-Agricultural Laboratories, Inc. 

 32380 Ave. 10 

 Madera, CA 93638 

 Analytical Laboratory: EN-CAS Analytical Laboratories, Inc. 

2359 Farrington Point Dr. 

 Winston-Salem, NC 27107 

 Identifying Codes: Pan-Agricultural Laboratories, Inc. FR-91-

311; EN-CAS Analytical Laboratories 91-

0041B CGAG; MRID 42851303; 

Unpublished 

SPONSOR: CIBA-GEIGY Corporation (currently Syngenta Crop Protection) 

 Greensboro, NC 27419 

EXECUTIVE SUMMARY: 

This study was designed to determine the dissipation of dislodgeable foliar residues (DFRs) of 

the active ingredient (ai) profenofos from treated cotton foliage. The test product was a 73% ai 

emulsifiable concentrate (EC) formulation. One test site was examined in Madera, CA (NAFTA 

Region 10) during the 1991 growing season. Geographical and climatic conditions were relevant 

to the use pattern proposed. The trial site consisted of one control plot and one treatment plot, 

with the treatment plot receiving six foliar broadcast spray applications of the test substance via 

tractor-mounted groundboom sprayers at a nominal rate of 1.0 lb ai/A/application. Applications 

were made using a spray volume of approximately 30 gallons per acre, at retreatment intervals of 

5-6 days. 

Page 60 of 95 Page 60 of 95
Page 5 of 19 

 

Single control plot and triplicate treated plot DFR samples were collected using a Birkestrand 

leaf punch sampler prior to and after the first, third, and sixth (last) application, and at the 

following intervals after the last application: 1, 2, 3, 7, 14, 21, 28, and 35 days. 

Residues were dislodged from the leaf punch samples immediately after collection using 0.004% 

Aerosol OT solution. The samples were stored frozen for up to 63 days prior to extraction for 

analysis by gas chromatography with flame photometric (GC/FPD). Concurrent recoveries were 

within the acceptable range of 70 to 120%. The reported limit of quantitation (LOQ) was 0.005 

μg/mL (0.003 μg/cm2

); the limit of detection (LOD) was not reported. 

Field fortification samples were prepared in duplicate at nominal level of 0.050 μg/mL (10 

μg/sample) for each DFR sampling interval. The samples were shipped and stored under the 

same conditions as the field samples, but were analyzed in separate analytical sets than the field 

samples. The overall average field fortification recovery was 80.0 ± 15.9%, with correction for 

laboratory recovery (uncorrected results were not provided). 

The Registrant provided DFRs in μg/sample with correction for laboratory recovery (uncorrected 

results were not provided) and in μg/cm2 (based on a 393 cm2 leaf surface area) with and without 

correction for the overall average field fortification recovery (80%). Versar calculated DFRs in 

μg/cm2 using the same field fortification correction factor, but used a leaf surface area of 400 

cm2. 

The highest average DFR was 1.66 μg/cm2, which occurred immediately after the first 

application (14.8% of application rate). The average DFR immediately prior to the last (sixth) 

application was 0.120 μg/cm2. The maximum average DFR after the last application occurred at 

the first sampling interval (after spray dried) with a value of 1.38 μg/cm2 (12.3% of application 

rate). DFRs declined rapidly in the first three days to 0.162 μg/cm2

 (1.4% of application rate) at 

3DAT6, and reached equilibrium at 21DAT6 with a value of 0.010 μg/cm2 (0.09% of application 

rate). DFRs on 28DAT6 and 35DAT6 were 0.011 and 0.0081 μg/cm2

, respectively. 

 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos. The Registrant conducted linear regression analyses using the natural logarithm of 

average DFR values from the following sampling intervals: 1) 0DAT6 through 35DAT6 (all 

sampling intervals after the last application), 2) 0DAT6 though 21DAT6 (sampling intervals 

through the point of equilibrium), 3) 0DAT6 through 3DAT6 (first part of bi-phasic pattern), and 

4) 3DAT6 through 35DAT6 (second part of bi-phasic pattern). The Registrant’s calculated halflives for these intervals, respectively, were 5.4 days (R2

 = 0.816), 3.4 days (R2 = 0.881), 1.0 days 

(R2

 = 0.942), and 7.9 days (R2 = 0.848). Additionally, the Registrant generated a decline curve fit 

using an equation representing the data specifically (y=a+bexp-x), as determined by Table Curve 

Fitting Software. The half-life calculated postapplication 6 was 0.7 days (R2 = 0.993). 

EPA first assumed first-order dissipation kinetics and conducted a linear regression analysis 

using the corrected average DFRs from immediately after the last application (0DAT6) through 

the last sampling interval (35DAT6), and determined a half-life of 5.4 days (R2 = 0.8212). 

However, the regression analysis did not appear visually to be a good fit for the data, and a 

Page 61 of 95 Page 61 of 95
Page 6 of 19 

comparison of the 0DAT6 actual and predicted DFRs show that the actual DFR (1.38 μg/cm2

) is 

~4x higher than the linear regression predicted DFR (0.3357 μg/cm2

). Therefore, EPA did 

additional analysis and conducted a biphasic (“hockey stick”) regression analysis using Excel’s 

Solver, and the corrected average DFRs from immediately after the last application through the 

last sampling interval. This regression analysis appears (visually) to be a better fit of the data, 

and provides a predicted Day 0 value of 1.74 μg/cm2

. 

There were some issues noted regarding the field fortification recovery samples: (1) only one 

field fortification level was used in the study, and the EPA guideline recommends a minimum of 

two field fortification levels; (2) the level chosen was below most of the field samples (10 

ug/sample for the field fortification samples vs a maximum of 648 ug/sample for the field 

samples); and (3) several recoveries were outside the guideline range of 70-120%. However, the 

study report did provide additional information with respect to laboratory recovery samples, 

which included concentrations up to 1000 ug/sample, with recoveries ranging from 88 – 121%; 

therefore, it is unlikely that the field fortification issues would impact the utility of the study for 

risk assessment. 

COMPLIANCE: Signed and dated GLP, Quality Assurance, and Data Confidentiality 

statements were provided. The study sponsor waived claims of confidentiality within the scope 

of FIFRA Section 10 (d) 1(A), (B), or (C). The Study Report indicated that the study was 

conducted under EPA Good Laboratory Practice Standards (40 CFR Part 160), with the 

following exceptions: Thirty-year averages for rainfall were based on data acquired from NOAA 

which were not collected in compliance with GLP; and ParsMadera on-site weather data were 

not collected under GLP. 

CONCURRENT EXPOSURE STUDY: No 

GUIDELINE OR PROTOCOL FOLLOWED: Series 875, Part B: Dislodgeable Foliar 

Residue Dissipation: Agricultural, Guideline 875.2100. A compliance checklist is provided in 

Appendix A. 

I. MATERIALS AND METHODS

A. MATERIALS:

1. Test Material: 

Formulation: Curacron® 8E, an EC formulation 

Lot/Batch # formulation: FL-910966 (formulated product) 

Formulation guarantee: 73% ai (8 lb ai/gal) nominal. Analysis of test substance on each 

application day yielded values 95 to 105% of nominal. 

Purity: 98.1% in technical 

CAS #: 41198-08-7 

Other Relevant Information: None 

2. Relevance of Test Material to Proposed Formulation(s): The test product used in this 

Page 62 of 95 Page 62 of 95
Page 7 of 19 

study, Curacron® 8E, appears to be the same product identified on the label for Curacron® 8E 

Insecticide-Miticide (EPA Reg. No. 100-669, dated 7/11/14) based on the product name, amount 

ai (73% ai), and crop use site (cotton). However, the EPA Reg No. provided in the study for the 

test product is 100-599, which was the registration number for the cancelled product Curacron 

6E containing 59.7% ai. 

B. STUDY DESIGN: The field phase study protocol (CIBA GEIGY Corporation Protocol 

No. 74-91), signed on June 27, 1991 by the Study Director, was provided with the Study Report. 

There were three amendments and one deviation to the protocol. The amendments involved 

adding the collection of fortified shipping stability samples, changing the Birkestrand leaf punch 

size to 2.5 cm in diameter instead of 1.75 cm in diameter, removing the collection of fortified 

leaf discs, and correcting the purity of the test substance. The deviation involved shipping the 

pre-treatment and post-treatment samples for application 1 at 15 days after collection, instead of 

within 14 days of collection. 

1. Site Description:

Test location: The field phase of the study was conducted at one location in Madera, CA 

(NAFTA Region 10). One control plot and one treated plot were established at the test site. Both 

the treated and control plots were divided into three replicate subplots. The treated plot was 

located 1,300 feet from the control plot. According to the study, the test site selected was typical 

for the intended use of profenofos insecticide and miticide, and was representative of the cottonproducing regions of the test state with respect to soil type and climate. 

Areas sprayed and sampled: The treated and untreated plots each measured 8 rows wide x 90 ft 

long. The exact width and area of each plot was not provided. 

Meteorological Data: On-site weather data were provided for the study duration (planting in 

May 1991 through last sampling interval in September 1991) for air temperature, soil 

temperature, wind speed, and precipitation. Additionally, weather conditions during the first five 

applications were provided, including air temperature, wind speed and direction, relative 

humidity, and percent cloud cover. Historical monthly average precipitation and air temperature 

data were also provided from a nearby NOAA station. 

Temperature and rainfall was similar to historical averages. As shown in Table 1 below, monthly 

mean minimum temperatures were 49 to 63°F, and monthly mean maximum temperatures were 

79 to 98°F. Precipitation was minimal, totalling 0 to 0.04 inches per month of the study. No 

rainfall occurred following the last application. In-furrow irrigation, using well water, was 

applied as needed to maintain normal crop growth and development. 

 

Table 1. Weather Conditions (Monthly) During Study Period 

Month Temperature (°F) 

(mean min/max) Total Rainfall (inches) Irrigation (inches) 

May 1991 49/79 0.04 4.5 

June 1991 54/89 0.00 4 

July 1991 63/98 0.01 6 

August 1991 59/92 0.00 5 

Page 63 of 95 Page 63 of 95
Page 8 of 19 

September 1991 58/94 0.01 5 

2. Crop Characteristics: 

Crop, variety: Cotton, variety not reported 

Row width, plant spacing: Not reported 

Stage of growth: Growth stages were reported only for the time of application, as noted 

below. 

1st application: Early bloom 

2nd application: Bloom 

3rd application: Late bloom/early square set 

4th application: Late bloom/ early square set 

5th application: Late bloom/early square set 

6th application: Boll set 

Other products used on crop: No maintenance pesticides were applied to the test plot during the 

trial, or during the previous two years. 

3. Application Rates and Regimes: 

Application rate(s): Six applications were made to cotton foliage at a target rate of 1.00 lb 

ai/A/application. The label reports a maximum application rate of 0.5 lb ai/A/application, with a 

maximum seasonal rate of 5 lb ai/A/season. 

Application Regime: Six foliar broadcast spray applications were made using a 5 to 6 day 

retreatment interval (7/24/91, 7/29/91, 8/3/91, 8/8/91, 8/13/91, 8/19/91). The label reports a 

minimum retreatment interval of 5 days. 

Application Equipment: Tractor-mounted Hahn Hi-boy commercial cotton sprayer fitted with 20 

D-6 nozzles, allowing for 5 nozzles per bed. One nozzle was positioned above the bed and two 

nozzles were positioned on either side of the plants. 

Spray Volume: 30 gallons per acre (GPA). The label reports a minimum spray volume of 3 to 5 

GPA for spray solutions diluted with water. 

Equipment Calibration Procedures: Sprayer calibrations were performed the day of each 

application (prior to application). The spray tank was partially filled with water, the pressure was 

adjusted to 50 psi, and the amount of time required to spray 5 gallons of water was checked and 

recorded three times. This information was used to calculate the flow rate in gallons per minute, 

and subsequently, the approximate tractor speed required to deliver the target application. The 

sprayer was timed over a distance of 90 feet. An example calculation was provided for the first 

application. 

Page 64 of 95 Page 64 of 95
Page 9 of 19 

Spray Verification: Spray verification was performed by placing 15 cm diameter filter paper (in 

petri dishes) in five random spots on the plot prior to each application. The samples were placed 

at varying heights to reflect the varying heights of the cotton canopy. The filter paper was 

collected immediately after each application and stored frozen until analysis. The average 

recoveries, based on the nominal application rate of 1 lb ai/A, were 24.6 ± 15.3% for application 

1, 33.6 ± 15.6% for application 2, 29.6± 5.8% for application 3, 34.5 ± 16.1% for application 4, 

35.8 ± 3.6% for application 5, and 13.8 ± 7.0% for application 6. The study report states that 

these recoveries reflect the fact that each petri dish would have only been exposed to 20-40% of 

the spray mix applied to each bed based on the positioning of the spray nozzles. 

4. Dislodgeable Foliar Residue Sampling Procedures: 

Method and Equipment: DFR samples consisted of 40 leaf disks which were collected with a 

~2.5 cm diameter leaf punch sampler. The punch samples were collected directly into prelabelled glass jars. 

Sampling Procedure: Leaf discs were collected from the entire row of each subplot, with the 

exception of the four plants on each end of the row. Discs were taken from alternating quadrants 

of the plant to decrease sample bias. The leaf surface was dry at each sampling event. After 

each sample was collected, the jar containing the leaf punches was removed from the punch 

apparatus, capped, placed in a cooler with ice or ice substitute, and taken to the dislodging area. 

Total Surface Area per Replicate: The total surface area of each sample was reported as 393 

cm2. For calculation purposes, HED assumed a leaf surface area of 400 cm2. 

Replicates per activity: 

 Replicates per sampling time: At each sampling interval, three treated replicate samples 

were collected from the treated plot. A single control sample was collected at each 

sampling interval from the untreated plot. 

 Number of sampling times: There were a total of 14 sampling events, including five 

sampling events before the last application. 

Times of sampling: Leaf samples were collected immediately before applications 1, 3, and 6, as 

soon as foliage dried after applications 1, 3, and 6, and at 1, 2, 3, 7, 14, 21, 28, and 35 days after 

application 6. 

Part(s) of foliage sampled: The leaf disks were collected from older but viable leaves along the 

middle towards the top of the leaf in an area representative of the estimated average leaf 

thickness. 

5. Sample Handling: After each sample was collected, the jar containing the leaf punches was 

removed from the punch apparatus, capped, stored in a cooler with ice substitute, and taken to 

the dislodging area (laboratory room of the Field Department of Pan-Ag Labs). After dislodging, 

all samples were placed in freezers set to maintain temperatures at or below freezing (-23.9oC to 

-3.3oC). All samples were shipped to EN-CAS Analytical Laboratories via Federal Express 

within 15 days of sampling. Samples were received at the analytical facility from August 8, 1991 

Page 65 of 95 Page 65 of 95
Page 10 of 19 

through September 25, 1991, and stored at a temperature between -23oC to -27oC until the 

samples were thawed for subsampling. The interval between sample collection and extraction 

for analysis was 24-63 days for field samples and 53-100 days for field fortification samples. 

6. Analytical Methodology: 

Dislodging Solution: Residues were dislodged with a 0.004% Aerosol® OT solution, prepared 

by diluting 0.2 ml of 75% Aerosol® OT with 100 mL water. 

Dislodging Procedure: In the field, the leaf disks were extracted twice with 100 mL of 0.004% 

Aerosol OT solution. Dislodging was conducted by shaking the sample for 10 minutes. The 

resulting solutions were combined (200 mL total) and the foliage was saved for possible 

analysis. 

Time Interval (sample collection to dislodging): According to the Study Report, samples 

were dislodged right after collection (exact times not provided). 

Detection methods: Sodium chloride was added to an aliquot of the dislodging solution 

sample, and then the sample was partitioned three times with hexanes:dichloromethane (80:20). 

The organic phases were filtered through a sodium sulphate pad and the phase was reduced to 

dryness, reconstituted, sonicated, and analyzed by gas chromatography with flame photometric 

detection (GC/FPD) in the phosphorous mode. A summary of the typical GS/FPD conditions are 

shown in Table 2. 

Table 2. Typical GC/FPD Instrument Parameters 

Instrument: Tracor Model 540 Gas chromatograph with a flame photometric detector 

(FPD) 

Column: Fused silica megabore capillary 15-M X 0.548 mm DB-5 column 

Gases 

Carrier: Helium = 1.0 mL/min 

Detector: Hydrogen = 100 mL/min 

 Air = 150 mL/min 

Injection Volume: 5.00 μL, direct 

Temperatures: Injector: 230°C 

Detector: 230°C 

Oven Temp.: 200°C 

Approximate Retention Times: 4.5 minutes 

Method validation: Residues of profenofos in dislodging solution were determined using 

method ENC-5/91. The method was verified prior to sample analysis using cotton leaf control 

dislodging solution samples fortified with profenofos at concentrations of 0.005, 0.05, and 0.5 

μg/mL. Individual method validation recoveries ranged from 96% to 113% with an overall mean 

recovery of 106% ± 5.94% (n= 9). The LOQ was 0.005 μg/mL (corresponding to 0.003 μg/cm2

leaf disk surface area based on a dislodging solution sample volume of 200 mL and a leaf surface 

area of 400 cm2

). The LOD was not reported.

Page 66 of 95 Page 66 of 95
Page 11 of 19 

Instrument performance: For all runs, standards of known concentration were injected at the 

beginning and end of the run, as well as interspersed throughout the run. These standards were 

used to construct linear regression standard curves. 

Quantification: Concentrations of profenofos were interpolated from the standard calibration 

curve, which was generated using linear regression. 

7. Quality Control: 

Lab Recovery: Two concurrent laboratory fortified samples were analyzed with each set of field 

samples. Control dislodging solution samples were fortified with profenofos at concentrations of 

0.005, 0.05, 0.5 and 5.0 μg/mL (assuming 200 mL samples = range of 1 μg/sample to 1000 

μg/sample). Individual concurrent laboratory recoveries ranged from 88% to 121%, with an 

overall mean recovery of 108% ± 10.7% (n=14). Residues of profenofos were not detected 

above the LOQ (0.003 μg/cm2) in any laboratory control samples. 

Field blanks: One control sample was collected at each sampling interval from the untreated 

plot. Residues of profenofos were not detected above the LOQ (0.003 μg/cm2) in the control 

samples. 

Field recovery: Field fortification samples were prepared at the end of each sampling interval. 

Samples were prepared in duplicate at one fortification level of 0.050 μg/mL (10 μg/sample) by 

adding 1 mL of a 10 μg/mL profenofos analytical standard to 200 mL of 0.004% Aerosol OT 

solution which had been shaken with control cotton leaf discs. A control blank of non-fortified 

Aerosol OT solution was also prepared at each interval. The samples were shipped and stored 

with the field samples, but were analyzed in separate analytical sets than the field samples. 

Table 3 provides a summary of the field fortification recoveries. The overall mean field 

fortification recovery was 80.0 ± 15.9%. The field fortification recoveries were corrected for 

concurrent laboratory recovery by the study author. Profenofos was not detected in any of the 

field fortification blank samples at any interval. 

Table 3. Summary of Field Fortification Recoveries

Sampling Interval Fortification Levela

 

(μg/sample) n Recoveries (%) b, c Average Recovery 

(%) 

Pre-App 1 

10 

(0.05 μg/mL) 

2 66, 104 85 

Post-App 1 2 64, 94 79 

Pre-App 3 2 74, 74 74 

Pre-App 3 2 80, 86 83 

Pre-App 6 2 76, 76 76 

Post-App 6 2 76, 52 64 

1DAT6 2 92, 84 88 

2DAT6 2 90, 82 86 

Page 67 of 95 Page 67 of 95
Page 12 of 19 

Table 3. Summary of Field Fortification Recoveries

Sampling Interval Fortification Levela

 

(μg/sample) n Recoveries (%) b, c Average Recovery 

(%) 

3DAT6 2 84, 90 87 

7DAT6 2 86, 74 80 

14DAT6 2 58, 80 69 

21DAT6 2 130, 92 111 

28DAT6 2 74, 74 74 

35DAT 2 48, 80 64 

Overall (n=28) 80.0±15.9 

a. Fortification level is equivalent to ~0.050 μg/mL, or 0.025 μg/cm2 based on a 400 cm2 sample 

b. Reported residues were corrected for concurrent laboratory recovery. 

c. Recoveries outside of 70-120% are in bold. 

Formulation: Curacron® 8E is an emulsifiable concentrate formulation containing a nominal 

73% of ai (8 lb ai/gal). Analysis of formulation samples taken at each application showed the 

amount of profenofos was 95 to 105% of nominal. 

Tank mix: Tank mix samples were collected in triplicate prior to each application. Average 

recoveries ranged from 19 to 102%, with an overall recovery of 42.3 ± 52.0% (n=18). The study 

stated that no reason could be found for the low recoveries. 

Travel Recovery: Travel recovery samples were not prepared. 

Storage Stability: A freezer storage stability study was conducted in which Aerosol OT 

dislodging solution was fortified with profenofos at 0.05 μg/mL and analyzed after 0, 1 and 3 

months of frozen storage. After correction for concurrent recovery, storage stability recoveries 

were 102, 95, and 105%, respectively. The storage stability data, in conjunction with the field 

fortification data, are adequate to demonstrate that residues of profenofos are stable in dislodging 

solution for the storage duration and conditions in the field study (24 to 63 days). 

II. RESULTS AND CALCULATIONS

The Registrant provided DFRs in μg/sample with correction for laboratory recovery (uncorrected 

results were not provided) and in μg/cm2 (based on a 393 cm2 leaf surface area) with and without 

correction for the overall average field fortification recovery (80.0%). EPA calculated DFRs in 

μg/cm2 using the same field fortification correction factor, but used a leaf surface area of 400 

cm2

. Table 4 provides a summary of the profenofos DFR values and statistical summaries 

calculated by EPA. 

The highest average DFR was 1.66 μg/cm2

, which occurred immediately after the first 

application (14.8% of application rate). The average DFR immediately prior to the last (sixth) 

application was 0.120 μg/cm2

. The maximum average DFR after the last application occurred at 

the first sampling interval (after spray dried) with a value of 1.38 μg/cm2 (12.3% of application 

Page 68 of 95 Page 68 of 95
Page 13 of 19 

rate). DFRs declined rapidly in the first three days to 0.162 μg/cm2

 (1.4% of application rate) at 

3DAT6, and reached equilibrium at 21DAT6 with a value of 0.010 μg/cm2

 (0.09% of application 

rate). DFRs on 28DAT6 and 35DAT6 were 0.011 and 0.0081 μg/cm2, respectively. 

 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos. The Registrant conducted linear regression analyses using the natural logarithm of 

average DFR values from the following sampling intervals: 1) 0DAT6 through 35DAT6 (all 

sampling intervals after the last application), 2) 0DAT6 though 21DAT6 (sampling intervals 

through the point of equilibrium), 3) 0DAT6 through 3DAT6 (first part of bi-phasic pattern), and 

4) 3DAT6 through 35DAT6 (second part of bi-phasic pattern). The Registrant’s calculated halflives for these intervals, respectively, were 5.4 days (R2

 = 0.816), 3.4 days (R2 = 0.881), 1.0 days 

(R2

 = 0.942), and 7.9 days (R2 = 0.848). Additionally, the Registrant generated a decline curve fit 

using an equation representing the data specifically (y=a+bexp-x), as determined by Table Curve 

Fitting Software. The half-life calculated post-application 6 was 0.7 days (R2

 = 0.993). 

EPA assumed first-order dissipation kinetics and conducted a linear regression analysis using the 

corrected average DFRs from immediately after the last application (0DAT6) through the last 

sampling interval (35DAT6), and determined a half-life of 5.4 days (R2

 = 0.8212). A 

comparison of the 0DAT6 actual and predicted DFRs show that the actual DFR (1.38 μg/cm2) is 

~4x higher than the predicted DFR (0.3357 μg/cm2). EPA’s dissipation curves and regression 

analysis results are presented in Appendix B and summarized in Table 5. 

III DISCUSSION:

There were some issues noted regarding the field fortification recovery samples: (1) only one 

field fortification level as used in the study, and the EPA guideline recommends a minimum of 

two field fortification levels; (2) the level chosen was below many of the field samples (10 

ug/sample for the field fortification samples vs a maximum of 648 ug/sample for the field 

samples); and (3) several recoveries were outside the guideline range of 70-120%. However, the 

study report did provide additional information with respect to laboratory recovery samples, 

which included concentrations up to 1000 ug/sample, with recoveries ranging from 88 – 121%. 

 

Page 69 of 95 Page 69 of 95
Page 14 of 19 

Table 4. DFRs for Cotton Leaves Treated with Profenofosa

Sampling 

Interval 

Measured 

Residue 

(μg)b 

DFR 

(μg/cm2)c 

Corrected 

DFR 

(μg/cm2)

d 

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application Rate 

Dislodgeablee

Pre-Treatment 1 

(-1DAT1) 

<LOQ <0.0025 0.0013 

0.0013 0.000 0.000 -6.68 

 

-- 

 <LOQ <0.0025 0.0013 

<LOQ <0.0025 0.0013 

Post-Treatment 1 

(0DAT1) 

642 1.61 2.01 

514 1.29 1.61 1.66 0.317 19.0 0.51 14.8 

442 1.11 1.38 

Pre-Treatment 3 

(5DAT2) 

50.8 0.127 0.159 

44.6 0.112 0.139 0.200 0.089 44.4 -1.61 1.8 

96.6 0.242 0.302 

Post-Treatment 3 

(0DAT3) 

592 1.48 1.85 

648 1.62 2.03 1.92 0.093 4.86 0.65 17.1

602 1.51 1.88 

Pre-Treatment 6 

(6DAT5) 

42.4 0.106 0.133 

40.2 0.101 0.126 0.120 0.016 13.4 -2.12 1.1 

32.6 0.082 0.102 

0DAT6 

628 1.57 1.96 

382 0.955 1.19 1.38 0.519 37.7 0.32 12.3

312 0.780 0.975 

1DAT6 

189 0.473 0.591 

139 0.348 0.434 0.449 0.135 30.1 -0.80 4.0

103 0.258 0.322 

2DAT6 

71.4 0.179 0.223 

63.0 0.158 0.197 0.227 0.032 14.3 -1.48 2.0

83.6 0.209 0.261 

3DAT6 

59.6 0.149 0.186 

31.4 0.079 0.098 0.162 0.056 34.4 -1.82 1.4 

64.4 0.161 0.201 

7DAT6 

28.2 0.071 0.088 

13.8 0.035 0.043 0.060 0.024 40.1 -2.81 0.54 

16.0 0.040 0.050 

14DAT6 

9.2 0.023 0.029 

6.2 0.016 0.019 0.026 0.006 21.7 -3.66 0.23 

9.4 0.024 0.029 

21DAT6 

3.4 0.0085 0.011 

3.6 0.0090 0.011 0.010 0.002 20.5 -4.63 0.09

2.4 0.0060 0.0075 

28DAT6 

3.6 0.0090 0.011 

3.8 0.0095 0.012 0.011 0.001 8.6 -4.51 0.10  

3.2 0.0080 0.010 

35DAT6 

2.0 0.0050 0.0063 

0.0081 0.002 27.7 -4.81 0.008 

2.4 0.0060 0.0075 

Page 70 of 95 Page 70 of 95
Page 15 of 19 

Table 4. DFRs for Cotton Leaves Treated with Profenofosa

Sampling 

Interval 

Measured 

Residue 

(μg)b 

DFR 

(μg/cm2)c 

Corrected 

DFR 

(μg/cm2)

d 

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application Rate 

Dislodgeablee

3.4 0.0085 0.0106 

a. Six applications were made at a rate of 1.0 lb ai/A/application (approx. 11.2 μg/cm2). 

b. LOQ = 0.003 μg/cm2

; LOD was not reported. 

c. DFR = Measured residue (μg) / leaf surface area (400 cm2

) 

d. DFR values were corrected for the average field fortification recovery (80.0%). For statistical calculations, residues <LOQ were 

assigned a value of 1⁄2 LOQ. 

e. Percent of Original Application Rate Dislodgeable = DFR (μg/cm2

) / Amount applied (μg/cm2) x 100%. 

 

Page 71 of 95 Page 71 of 95
Page 16 of 19 

Appendix A: First Order Kinetics Regression 

Study Summary 

MRID 42851303 

Crop Cotton 

Region/State Region 10/California 

Application Rate (lb ai/acre) 1 

Dislodgeable Foliar Residue (DFR) Analysis 

Re-entry Day 

(Day After Treatment) 

Measured DFR (ug/cm2

) 

Individual Samples Average Standard Deviation 

0.000 

1.9625 

1.1938 1.38 0.5186 

0.9750 

1.00 

0.5906 

0.4344 0.449 0.1350 

0.3219 

2 

0.2231 

0.1969 0.227 0.0324 

0.2613 

3 

0.1863 

0.0981 0.162 0.0557 

0.2013 

7 

0.0881 

0.0431 0.0604 0.0242 

0.0500 

14 

0.0288 

0.0258 0.0056 0.0194 

0.0294 

21 

0.0106 

0.0113 0.0098 0.0020 

0.0075 

28 

0.0113 

0.0119 0.0110 0.0010 

0.0100 

35 

0.0063 

0.0075 0.0081 0.0023 

0.0106 

Page 72 of 95 Page 72 of 95
Page 17 of 19 

EPA/OPP/HED 1st Order Kinetics 

DAT ln(DFR) Modeled (ln DFR) Modeled DFR 

0.00 0.320 -1.091 0.336 

1.00 -0.801 -1.221 0.295 

2 -1.482 -1.350 0.259 

3 -1.821 -1.480 0.228 

7 -2.806 -1.998 0.136 

14 -3.656 -2.904 0.055 

21 -4.626 -3.810 0.022 

28 -4.506 -4.716 0.009 

35 -4.813 -5.622 0.004 

Residue Dissipation 

Decay constant (k) -0.129 

Daily Dissipation (%) 12% 

Half-life (days) 5.4 

Initial Residue C0 (ug/cm2

) 0.3357 

% of application rate 2.99% 

 

Page 73 of 95 Page 73 of 95
Page 18 of 19 

 

y = -0.1294x - 1.0915

R2 = 0.8212

-6.000

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

ln DFR (ug/cm2)

DAT

ln DFR vs. DAT

Page 74 of 95 Page 74 of 95
Page 19 of 19 

Appendix B: Biphasic (“Hockey Stick”) Regression 

"Hockey Stick" 

(untransformed residuals) 

Modeled DFR Squared Residuals 

1.38 0.34

1.38 0.03

1.38 0.16

0.45 0.02

0.45 0.00

0.45 0.02

0.22 0.00

0.22 0.00

0.22 0.00

0.17 0.00

0.17 0.01

0.17 0.00

0.06 0.00

0.06 0.00

0.06 0.00

0.01 0.00

0.01 0.00

0.01 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

Sum of Squared Errors (SSE) 0.59

C0 (ug/cm2) 1.7

C0: % of application rate 15%

Decay constant 1 (k1) -1.345

Decay constant 2 (k2) -0.251

Inflection Point (day) 1

Page 75 of 95 Page 75 of 95
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: 15-SEP-2015 

OFFICE OF CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Profenofos: Review of "Dissipation of Dislodgeable Foliar Residues of 

Profenofos (Curacron® 8E) Applied to Cotton in Texas" 

PC Code: 111401 

Decision Number: 482022 

Petition Number: NA 

Risk Assessment Type: NA 

TXR Number: NA 

MRID Numbers: 42851304 

DP Barcode: D429108 

Registration Number: NIA 

Regulatory Action: NIA 

Case Number: 2540 

CAS Number: 41198-08-7 

40CFR: § 180.404 

FROM: Kelly Lowe, Environmental Scientist 

Risk Assessment Branch I (RAB I) 

Health Effects Division (HED), 7509P 

THROUGH: 

TO: 

Thurston Morton, Acting Branch Chief 

RABI I HED, 7509P 

Christina Scheltema 

Patricia Parrott 

Pesticide Re-Evaluation Division (PRD) (7508P) 

ACTION REQUESTED: 

The Registration Division (RD) requested that the Health Effects Division (HED) conduct a 

review of the submitted dislodgeable foliar residue study for profenofos. 

SUMMARY OF STUDY RESULTS: 

This study was designed to determine the dissipation of dislodgeable foliar residues (DFRs) of 

the active ingredient (ai) profenofos from treated cotton foliage. The test product was a 73% ai 

emulsifiable concentrate (EC) formulation. One test site was examined in Snook, Texas 

(NAFTA Region 6) during the 1991 growing season. Geographical and climatic conditions were 

relevant to the use pattern proposed. The trial site consisted of one control plot and one 

treatment plot, with the treatment plot receiving six foliar broadcast spray applications of the test 

substance via tractor-mounted groundboom sprayers at a nominal rate of 1. 0 lb ai/ Napplication. 

Page I of 20 

Page 76 of 95
Page 2 of 20 

Applications were made using a spray volume between 19.4-21.5 gallons per acre, at retreatment 

intervals of 5-7 days. 

 

Single control plot and triplicate treated plot DFR samples were collected using a Birkestrand 

leaf punch sampler prior to and after the first, third, and sixth (last) application, and at the 

following intervals after the last application: 1, 2, 3, 7, 14, 21, 28, and 35 days. EPA calculated 

DFRs in μg/cm2 using the same field fortification correction factor, and used a leaf surface area 

of 400 cm2. 

The highest average DFR was 2.11 μg/cm2, which occurred immediately after the first 

application (20.4% of application rate). The average DFR immediately prior to the last (sixth) 

application was 0.054 μg/cm2. The maximum average DFR after the last application occurred at 

the first sampling interval (after spray dried) with a value of 1.74 μg/cm2 (16.0% of application 

rate). DFRs declined rapidly in the first three days to 0.076 μg/cm2 (0.7% of application rate) at 

3DAT6, and reached equilibrium at 21DAT6 with a value of 0.0086 μg/cm2 (0.08% of 

application rate). DFRs on 28DAT6 and 35DAT6 were 0.0066 and 0.0086 μg/cm2, respectively. 

 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos. The Registrant conducted linear regression analyses using the natural logarithm of 

average DFR values from the following sampling intervals: 1) 0DAT6 through 35DAT6 (all 

sampling intervals after the last application), 2) 0DAT6 though 21DAT6 (sampling intervals 

through the point of equilibrium), 3) 0DAT6 through 3DAT6 (first part of bi-phasic pattern), and 

4) 3DAT6 through 35DAT6 (second part of bi-phasic pattern). The Registrant’s calculated halflives for these intervals, respectively, were 5.7 days (R2

 = 0.659), 3.4 days (R2 = 0.723), 16 hours 

(R2

 = 0.924), and 10.8 days (R2 = 0.731). 

EPA first assumed first-order dissipation kinetics and conducted a linear regression analysis 

using the corrected average DFRs from immediately after the last application (0DAT6) through 

the last sampling interval (35DAT6), and determined a half-life of 5.7 days (R2 = 0.6694). 

However, the regression analysis did not appear visually to be a good fit for the data, and a 

comparison of the 0DAT6 actual and predicted DFRs show that the actual DFR (1.74 μg/cm2

) is 

~4x higher than the linear regression predicted DFR (0.2005 μg/cm2

). Therefore, EPA did 

additional analysis and conducted a biphasic (“hockey stick”) regression analysis using Excel’s 

Solver, and the corrected average DFRs from immediately after the last application through the 

last sampling interval. This regression analysis appears (visually) to be a better fit of the data, 

and provides a predicted Day 0 value of 2.4 μg/cm2

. 

CONCLUSIONS:

No major issues were identified during review of this study and the results are considered 

acceptable for risk assessment purposes. 

There were some issues noted regarding the field fortification recovery samples: (1) only one 

field fortification level as used in the study, and the EPA guideline recommends a minimum of 

two field fortification levels; (2) the level chosen was below most of the field samples (10 

ug/sample for the field fortification samples vs a maximum of 648 ug/sample for the field 

samples); and (3) several recoveries were outside the guideline range of 70-120%. However, the 

Page 77 of 95 Page 77 of 95
Page 3 of 20 

study report did provide additional information with respect to laboratory recovery samples, 

which included concentrations up to 1000 ug/sample, with recoveries ranging from 88 – 121%.

Summary of DFR Values and Regression Analysis Results for Treated Cotton with Profenofos (MRID# 

42851303). 

Cotton; Site: Snook, TX 

Study Target Rate (lb ai/A) 1.00 lb ai/A 

Spray Volume (GPA) 19.4-21.5 

Measured Average Day 0 Residue (μg/cm2) 0DAT6: 1.74 

Linear Regression Predicted Day 0 Residue (μg/cm2) 0DAT6: 0.2005 

Slope -0.121 

Half-life (days) 5.7 

R2 0.6694 

Biphasic Regression Predicted Day 0 Residue (ug/cm2) 0DAT6: 2.4 

Slope -2.015, -0.272 

0

0.5

1

1.5

2

2.5

3

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

DFR (ug/cm2)

DAT

42851303_profenofos_TX

Residue (ug/cm2) vs. Time (days)

Raw DFR Data

Log-linear 1st Order

Non-linear 1st Order

Hockey Stick

Page 78 of 95 Page 78 of 95
Page 4 of 20 

DATA EVALUATION RECORD

STUDY TYPE: Determination of Dislodgeable Foliar Residues on Cotton Treated with 

Profenofos; OCSPP 875.2100 

PC CODE: 111401 

TEST MATERIAL Curacron® 8E, an emulsifiable concentrate (EC) formulation containing 

73% of active ingredient (ai) profenofos (8 lb ai/gal) 

SYNONYMS: Common name: Profenofos 

Formulation Trade name: Curacron® 8E 

Chemical name: 0-(4-bromo-2-chlorphenyl) 0-ethyl S-propyl 

phosphorothioate 

CAS No.: 41198-08-7 

CITATION: Author: R.C. Jordan 

Title: Dissipation of Dislogdgeable Foliar 

Residues of Profenofos (Curacron® 8E) 

Applied to Cotton in Texas 

Report Date: March 8, 1993 

Field Research Laboratory: American Agricultural Services, Inc. 

 P.O. Box 12193 

 Cary, NC 27512 

 Analytical Laboratory: EN-CAS Analytical Laboratories, Inc. 

2359 Farrington Point Dr. 

 Winston-Salem, NC 27107 

 Identifying Codes: CIBA-GEIGY Corporation 75-91; EN-CAS 

Analytical Laboratories 91-0041A CGAG; 

MRID 42851304; Unpublished 

SPONSOR: CIBA-GEIGY Corporation (currently Syngenta Crop Protection) 

 Greensboro, NC 27419 

EXECUTIVE SUMMARY: 

This study was designed to determine the dissipation of dislodgeable foliar residues (DFRs) of 

the active ingredient (ai) profenofos from treated cotton foliage. The test product was a 73% ai 

emulsifiable concentrate (EC) formulation. One test site was examined in Snook, Texas 

(NAFTA Region 6) during the 1991 growing season. Geographical and climatic conditions were 

relevant to the use pattern proposed. The trial site consisted of one control plot and one 

treatment plot, with the treatment plot receiving six foliar broadcast spray applications of the test 

substance via tractor-mounted groundboom sprayers at a nominal rate of 1.0 lb ai/A/application. 

Applications were made using a spray volume between 19.4-21.5 gallons per acre, at retreatment 

Page 79 of 95 Page 79 of 95
Page 5 of 20 

intervals of 5-7 days. 

 

Single control plot and triplicate treated plot DFR samples were collected using a Birkestrand 

leaf punch sampler prior to and after the first, third, and sixth (last) application, and at the 

following intervals after the last application: 1, 2, 3, 7, 14, 21, 28, and 35 days. 

Residues were dislodged from the leaf punch samples immediately after collection using 0.004% 

Aerosol OT solution. The samples were stored frozen for up to 73 days prior to extraction for 

analysis by gas chromatography with flame photometric (GC/FPD). Concurrent recoveries were 

generally within the acceptable range of 70 to 120%. The reported limit of quantitation (LOQ) 

was 0.005 μg/mL (0.003 μg/cm2

); the limit of detection (LOD) was not reported. 

Field fortification samples were prepared in duplicate at a nominal level of 0.050 μg/mL (11.3 

μg/sample) for each DFR sampling interval. The samples were shipped and stored under the 

same conditions as the field samples, but were analyzed in separate analytical sets than the field 

samples. The overall average field fortification recovery was 113±16.5%, with correction for 

laboratory recovery (uncorrected results were not provided). 

The Registrant provided DFRs in μg/sample with correction for laboratory recovery (uncorrected 

results were not provided) and in μg/cm2 (based on a 404 cm2 leaf surface area) with and without 

correction for the overall average field fortification recovery (113%). EPA calculated DFRs in 

μg/cm2 using the same field fortification correction factor, but used a leaf surface area of 400 

cm2

. 

The highest average DFR was 2.11 μg/cm2

, which occurred immediately after the first 

application (20.4% of application rate). The average DFR immediately prior to the last (sixth) 

application was 0.054 μg/cm2. The maximum average DFR after the last application occurred at 

the first sampling interval (after spray dried) with a value of 1.74 μg/cm2

 (16.0% of application 

rate). DFRs declined rapidly in the first three days to 0.076 μg/cm2 (0.7% of application rate) at 

3DAT6, and reached equilibrium at 21DAT6 with a value of 0.0086 μg/cm2

 (0.08% of 

application rate). DFRs on 28DAT6 and 35DAT6 were 0.0066 and 0.0086 μg/cm2

, respectively. 

 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos. The Registrant conducted linear regression analyses using the natural logarithm of 

average DFR values from the following sampling intervals: 1) 0DAT6 through 35DAT6 (all 

sampling intervals after the last application), 2) 0DAT6 though 21DAT6 (sampling intervals 

through the point of equilibrium), 3) 0DAT6 through 3DAT6 (first part of bi-phasic pattern), and 

4) 3DAT6 through 35DAT6 (second part of bi-phasic pattern). The Registrant’s calculated halflives for these intervals, respectively, were 5.7 days (R2

 = 0.659), 3.4 days (R2 = 0.723), 16 hours 

(R2 = 0.924), and 10.8 days (R2 = 0.731). 

EPA first assumed first-order dissipation kinetics and conducted a linear regression analysis 

using the corrected average DFRs from immediately after the last application (0DAT6) through 

the last sampling interval (35DAT6), and determined a half-life of 5.7 days (R2 = 0.6694). 

However, the regression analysis did not appear visually to be a good fit for the data, and a 

Page 80 of 95 Page 80 of 95
Page 6 of 20 

comparison of the 0DAT6 actual and predicted DFRs show that the actual DFR (1.74 μg/cm2

) is 

~4x higher than the linear regression predicted DFR (0.2005 μg/cm2

). Therefore, EPA did 

additional analysis and conducted a biphasic (“hockey stick”) regression analysis using Excel’s 

Solver, and the corrected average DFRs from immediately after the last application through the 

last sampling interval. This regression analysis appears (visually) to be a better fit of the data, 

and provides a predicted Day 0 value of 2.4 μg/cm2

. 

There were two issues noted in the review of the study. One was with regard to the field 

fortification recoveries. It was noted that (1) only one field fortification level was used; the EPA 

guideline recommends a minimum of two field fortification levels; (2) the level chosen was 

below many of the field samples (11.3 ug/sample for the field fortification samples vs a 

maximum of 1,300 ug/sample for the field samples); and (3) several recoveries were outside the 

guideline range of 70-120%. However, the study report did provide additional information with 

respect to laboratory recovery samples, which included a range of concentrations from 1.125 

ug/sample up to 1,125 ug/sample, with recoveries ranging from 92 – 134%; therefore, it is 

unlikely that the field fortification issues would impact the utility of the study for risk 

assessment. The other issue of note in the study is that profenofos residues were detected in the 

untreated control plot samples and in the blank field fortification samples at all sampling 

intervals except for the pre- and post- treatment 1 intervals. The profenofos levels were 1.58 to 

16.0 μg for the untreated control plot samples and 1.58 to 4.28 μg for the field fortification blank 

samples. 

COMPLIANCE: 

Signed and dated GLP, Quality Assurance, and Data Confidentiality statements were provided. 

The study sponsor waived claims of confidentiality within the scope of FIFRA Section 10 (d) 

1(A), (B), or (C). The Study Report indicated that the study was conducted under EPA Good 

Laboratory Practice Standards (40 CFR Part 160). 

CONCURRENT EXPOSURE STUDY: No 

GUIDELINE OR PROTOCOL FOLLOWED: Series 875, Part B: Dislodgeable Foliar 

Residue Dissipation: Agricultural, Guideline 875.2100. A compliance checklist is provided in 

Appendix A. 

I. MATERIALS AND METHODS

A. MATERIALS:

1. Test Material: 

Formulation: Curacron® 8E, an EC formulation 

Lot/Batch # formulation: FL-910966 (formulated product) 

Formulation guarantee: 73% ai (8 lb ai/gal) nominal, 73.2% purity analysis (assay date 

5/14/93) 

Purity: 98.1% in technical 

Page 81 of 95 Page 81 of 95
Page 7 of 20 

CAS #: 41198-08-7 

Other Relevant Information: None 

2. Relevance of Test Material to Proposed Formulation(s):

The test product used in this study, Curacron® 8E, appears to be the same product identified on 

the label for Curacron® 8E Insecticide-Miticide (EPA Reg. No. 100-669, dated 7/11/14) based 

on the product name, amount ai (73% ai), and crop use site (cotton). 

B. STUDY DESIGN:

The field phase study protocol (CIBA GEIGY Corporation Protocol No. 75-91), signed on July 

2, 1991 by the Study Director, was provided with the Study Report. There were three 

amendments and one deviation to the protocol. The amendments involved altering the field 

project coordinator, adding information on soil characterization, and clearly defining test plots 

and correcting grammatical errors. The deviation involved field extracted and fortification leaf 

disks that were intended for analysis in the event of very low 0-day residues or highly variable 

study residues. Neither event actually occurred. 

1. Site Description:

Test location: The field phase of the study was conducted at one location in Snook, Texas 

(NAFTA Region 6). One control plot and one treated plot were established at the test site. The 

treated plot was divided into three replicate subplots. The treated plot was located at 217 feet 

from the control plot. According to the study, the test site selected was typical for the intended 

use of profenofos insecticide and miticide, and was representative of the cotton-producing 

regions of the test state with respect to soil type and climate. 

Areas sprayed and sampled: 

 Treated Plot: 60 ft x 95 ft (5,700 ft2); each sub plot was 20 ft x 95 ft (1,900 ft2) 

 Control Plot: 60 ft x 80 ft (4,800 ft2) 

Meteorological Data: Weather data were provided for the study duration (planting in May 1991 

through last sampling interval in September 1991) for air temperature (daily minimum and 

maximum) and precipitation (daily). Precipitation was monitored on-site and temperature was 

monitored from a nearby airport (~4 miles away). Additionally, on-site weather data were 

collected on the time of each application for wind speed/direction, air and soil temperature, % 

cloud cover, and first rainfall after application. Historical monthly average precipitation and air 

temperature data were also provided (measured ~2-4 miles away). Temperature was considered 

normal during the trial period. As shown in Table 1 below, monthly mean minimum 

temperatures were 66 to 73°F and monthly mean maximum temperatures were 89 to 96°F. The 

first rainfall after application occurred 40 minutes (0.1 in.) for application 4, and 3 to 14 days for 

the remaining applications (0.1 to 0.25 in.). Precipitation totalled 0 to 5.54 inches per month of 

the study, and was considered below normal in July during the application phase and above 

normal in August after the last application. The first rainfall after the last application occurred on 

3DAT6 (0.25 in.). Rainfall after the last application also occurred on 12DAT6 (0.73 in.), 

13DAT6 (0.1 in.), 19 DAT6 (0.05 in.), 28DAT6 (2.1 in.), and 32-35DAT6 (4.83 in.). The 

Page 82 of 95 Page 82 of 95
Page 8 of 20 

rainfall on 28DAT6 occurred prior to sample collection, however, plants were allowed to dry 

prior to collection. In-furrow irrigation, using river water, was applied once to maintain normal 

crop growth and development. 

 

Table 1. Weather Conditions (Monthly) During Study Period 

Month Temperature (°F) (mean 

min/max) 

Total Rainfall 

(inches) 

Irrigation 

(inches) 

May 1991 67/92 0.00 - 

June 1991 66/94 5.54 - 

July 1991 73/95 0.22 2.00 

August 1991 73/96 3.22 0.00 

September 1991 73/89 4.83 0.00 

2. Crop Characteristics: 

Crop, variety: Cotton, D&PL90 

Row width, plant spacing: Not reported 

Stage of growth: The first application was made approximately 1 week before full bloom and 

each subsequent application was made at 5-7 day intervals. The growth stage at each sampling 

interval was not provided. 

Other products used on crop: Fertilizer and maintenance pesticides were applied as needed 

during the trial period. Maintenance chemicals applied included Cotoran 4L, Karmex 4L, 

MSMA 6E, Orthene 90S, Vydate, Vydate CLU, Capture PBO8, and Azodrin. No 

orgnophosaphate pesticides were applied within 2 weeks of the initial test substance application. 

3. Application Rates and Regimes: 

Application rate(s): Six applications were made to cotton foliage at a target rate of 1.00 lb 

ai/A/application for a total seasonal rate of 6 lb ai/application. The actual application rates were 

0.92 lb ai/A for the first application, 1.02 lb ai/A for the second and third applications, 0.99 lb 

ai/A for the fourth application, and 0.97 lb ai/A for the fifth and sixth applications. The label 

reports a maximum application rate of 0.5 lb ai/A/application, with a maximum seasonal rate of 

5 lb ai/A/season. 

Application Regime: Six foliar broadcast spray applications were made using a 5-7 day 

retreatment interval (7/8/1991, 7/13/1991, 7/18/1991, 7/23/1991, 7/28/1991, and 8/2/1991). The 

label reports a minimum retreatment interval of 5 days. 

Application Equipment: John Deere Hi-cycle sprayer with a 20-ft boom (12 nozzle spaced at 20 

inches). 

 

Spray Volume: 19.4-21.5 gallons per acre (GPA). The label reports a minimum spray volume 

Page 83 of 95 Page 83 of 95
Page 9 of 20 

of 3 to 5 GPA for spray solutions diluted with water. 

Equipment Calibration Procedures: Sprayer calibrations were performed the day of each 

application (prior to application) by measuring the output of the 12 nozzles for 30 seconds. The 

tractor speed was calculated from three test runs prior to each application. 

Spray Verification: Spray verification was performed by placing 15 cm diameter filter paper (in 

petri dishes) in each subplot prior to each application. The samples were placed at crop canopy 

level. The filter paper was collected immediately after each application and stored frozen until 

analysis. Based on the nominal application rate of 1 lb ai/A, the average percent profenofos 

expected per application ranged from 14.5±2.2% (application 6) to 66.3±4.0% (application 1), 

with a mean of 50.3±29.4% 

4. Dislodgeable Foliar Residue Sampling Procedures: 

Method and Equipment: DFR samples consisted of 40 leaf disks which were collected with a 

~2.5 cm diameter leaf punch sampler. The punch samples were collected directly into prelabelled glass jars. 

Sampling Procedure: Leaf discs were collected by avoiding the outer rows and a 10 ft. border at 

each plot. The leaf surface was dry at each sampling event. After each sample was collected, 

the jar containing the leaf punches was removed from the punch apparatus, capped, placed in a 

cooler with ice or ice substitute, and taken to the dislodging area. 

Total Surface Area per Replicate: The total surface area of each sample was reported as 404 cm2. 

For calculation purposes, HED assumed a leaf surface area of 400 cm2. 

Replicates per activity: 

 Replicates per sampling time: At each sampling interval, three treated replicate samples 

were collected from the treated plot. A single control sample was collected at each 

sampling interval from the untreated plot. 

 Number of sampling times: There were a total of 14 sampling events, including five 

sampling events before the last application. 

Times of sampling: Leaf samples were collected immediately before applications 1, 3, and 6, as 

soon as foliage dried after applications 1, 3, and 6, and at 1, 2, 3, 7, 14, 21, 28, and 35 days after 

application 6. 

Part(s) of foliage sampled: The leaf disks were cut from the center of a leaf excluding any 

primary veins. 

Page 84 of 95 Page 84 of 95
Page 10 of 20 

5. Sample Handling: After each sample was collected, the jar containing the leaf punches was 

removed from the punch apparatus, capped, stored in a cooler with ice substitute, and taken to 

the dislodging area (laboratory room of the Nemec Aqriservices, Inc.). The extraction was 

performed by Nemec Agriservies, Inc. personnel, but Nemec Agriservices did not participate in 

the collection of the leaf disks. After dislodging, all samples were placed in freezers set to 

maintain temperatures at or below freezing (-18oC to -29oC). All samples were shipped to ENCAS Analytical Laboratories via ACDS freezer truck within 19 days of sampling. Samples were 

received at the analytical facility from August 2, 1991 through September 24, 1991 and stored at 

a temperatures between -23oC to -27oC until the samples were thawed for subsampling. The 

interval between sample collection and extraction for analysis was 40-73 days for field samples 

and 63-105 days for field fortification samples. 

6. Analytical Methodology: 

Dislodging Solution: Residues were dislodged with a 0.004% Aerosol® OT solution, prepared 

by diluting 2 mL of 75% Aerosol® OT with 100 mL water. 

Dislodging Procedure: In the field, the leaf disks were extracted three times with 75 mL of 

0.004% Aerosol OT solution by shaking the sample for 2 minutes per extraction. The resulting 

solutions were combined (225 mL total) and the foliage was saved for possible analysis. 

Time Interval (sample collection to dislodging): According to the Study Report, samples were 

dislodged right after collection (exact times not provided). 

Detection methods: Sodium chloride was added to an aliquot of the dislodging solution sample, 

and then the sample was partitioned three times with hexanes:dichloromethane (80:20). The 

organic phases were filtered through a sodium sulfate pad and the phase was reduced to dryness, 

reconstituted, sonicated, and analyzed by gas chromatography with flame photometric detection 

(GC/FPD) in the phosphorous mode. A summary of the typical GC/FPD conditions are shown in 

Table 2. 

Table 2. Typical GC/FPD Instrument Parameters 

Instrument: Tracor Model 540 Gas chromatograph with a flame photometric detector 

(FPD) 

Column: Fused silica megabore capillary 15-M X 0.548 mm DB-5 column 

Gases 

Carrier: Helium = 1.0 mL/min 

Detector: Hydrogen = 100 mL/min 

 Air = 150 mL/min 

Injection Volume: 5.00 μL, direct 

Temperatures: Injector: 230°C 

Detector: 230°C 

Oven Temp.: 200°C 

Approximate Retention Times: 4.2 minutes 

Page 85 of 95 Page 85 of 95
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Method validation: Residues of profenofos in dislodging solution were determined using method 

ENC-5/91. The method was verified prior to sample analysis using cotton leaf control 

dislodging solution samples fortified with profenofos at concentrations of 0.005, 0.05, and 0.5 

μg/mL. Individual method validation recoveries (with correction for residues in control) ranged 

from 90% to 102% with an overall mean recovery of 97% ± 3.7% (n= 9). The LOQ was 0.005 

μg/mL (corresponding to 0.003 μg/cm2

 leaf disk surface area based on a dislodging solution 

sample volume of 225 mL and a leaf surface area of 400 cm2

). The LOD was not reported.

Instrument performance: For all runs, standards of known concentration were injected at the 

beginning and end of the run, as well as interspersed throughout the run. 

Quantification: Concentrations of profenofos were interpolated from the standard calibration 

curve, which was generated using linear regression. 

7. Quality Control: 

Lab Recovery: Two concurrent laboratory fortified samples were analyzed with each set of field 

samples. Control dislodging solution samples were fortified with profenofos at concentrations of 

0.005, 0.05, 0.5 and 5.0 μg/mL (assuming 225 mL samples = range of 1.125 μg/sample to 1,125 

μg/sample). Individual concurrent laboratory recoveries (corrected for any control contribution) 

ranged from 92% to 134%, with an overall mean recovery of 112% ± 11.2% (n=14). Residues of 

profenofos were not detected above the LOQ (0.003) in the lab controls, but were detected at 

0.0002 μg/mL in one laboratory control sample. 

Field blanks: One control sample was collected at each sampling interval from the untreated 

plot. Residues of profenofos were not detected above the LOQ at the pre- or post-treatment 1 

intervals, but were detected at all other sampling intervals at levels ranging from 0.004 to 0.040 

μg/cm2. 

Field recovery: Field fortification samples were prepared at the end of each sampling interval. 

Samples were prepared in duplicate at one fortification level of 0.050 μg/mL (11.3 μg 

profenofos/225 mL of 0.004% Aerosol OT solution which had been shaken with control cotton 

leaf discs). A control blank of non-fortified Aerosol OT solution was also prepared at each 

interval. The samples were shipped and stored with the field samples, but were analyzed in 

separate analytical sets than the field samples. 

Page 86 of 95 Page 86 of 95
Page 12 of 20 

The profenofos residues found in the field fortification samples were reported with correction for 

individual control contribution, which were <LOQ at the pre- and post-treatment 1 intervals and 

were detected at 0.007 to 0.019 μg/mL at all other sampling intervals. Additionally, the 

profenofos residues were corrected for concurrent laboratory recovery. Table 3 provides a 

summary of the field fortification recoveries. The overall mean field fortification recovery was 

113±16.5%. The profenofos levels found in the DFR samples bracketed the fortification level. 

Table. 3 Summary of Field Fortification Recoveries

Sampling Interval Fortification Levela

 

(μg/sample) n Recoveries (%)b,c Average Recovery 

(%) 

Pre-App 1 

11.3 

(0.05 μg/mL) 

2 84, 94 89 

Post-App 1 2 100, 92 96 

Pre-App 3 2 100, 97 99 

Pre-App 3 2 110, 102 106 

Pre-App 6 2 104, 92 98 

Post-App 6 2 104, 100 102 

1DAT6 2 134, 121 127 

2DAT6 2 113, 119 116 

3DAT6 2 112, 105 108 

7DAT6 2 121, 129 125 

14DAT6 2 142, 124 133 

21DAT6 2 142, 113 127 

28DAT6 2 116, 126 121 

35DAT6 2 129, 145 137 

Overall (n=28) 113±16.5 

a. Fortification level is equivalent to ~0.050 μg/mL, or 0.028 μg/cm2 based on a 400 cm2 sample. 

b. Reported residues were corrected for the control contribution and concurrent laboratory recovery. 

c. Recoveries outside of 70-120% are in bold. 

Formulation: Curacron® 8E is an emulsifiable concentrate formulation containing a nominal 

73% of ai (8 lb ai/gal). Analysis of formulation samples taken at each application showed the 

amount of profenofos was 93 to 107% of nominal. 

Tank mix: Tank mix samples were collected in duplicate prior to each application. Average 

recoveries ranged from 27.6 to 74.9%, with an overall recovery of 43.5 ± 17.2% (n=18). The 

study stated that no reason could be found for the low recoveries. 

Travel Recovery: Travel recovery samples were not prepared. 

Page 87 of 95 Page 87 of 95
Page 13 of 20 

Storage Stability: A storage stability study was not conducted. 

II. RESULTS AND CALCULATIONS

The Registrant provided DFRs in μg/sample with correction for laboratory recovery (uncorrected 

results were not provided) and in μg/cm2 (based on a 404 cm2 leaf surface area) with and without 

correction for the overall average field fortification recovery (113.0%). EPA calculated DFRs in 

μg/cm2

 using the same field fortification correction factor, but used a leaf surface area of 400 

cm2

. Table 4 provides a summary of the profenofos DFR values and statistical summaries 

calculated by EPA. 

The highest average DFR was 2.11 μg/cm2, which occurred immediately after the first 

application (20.4% of application rate). The average DFR immediately prior to the last (sixth) 

application was 0.054 μg/cm2. The maximum average DFR after the last application occurred at 

the first sampling interval (after spray dried) with a value of 1.74 μg/cm2

 (16.0% of application 

rate). DFRs declined rapidly in the first three days to 0.076 μg/cm2 (0.7% of application rate) at 

3DAT6, and reached equilibrium at 21DAT6 with a value of 0.0086 μg/cm2

 (0.08% of 

application rate). DFRs on 28DAT6 and 35DAT6 were 0.0066 and 0.0086 μg/cm2, respectively. 

 

The Registrant assumed first-order dissipation kinetics to generate dissipation curves for 

profenofos. The Registrant conducted linear regression analyses using the natural logarithm of 

average DFR values from the following sampling intervals: 1) 0DAT6 through 35DAT6 (all 

sampling intervals after the last application), 2) 0DAT6 though 21DAT6 (sampling intervals 

through the point of equilibrium), 3) 0DAT6 through 3DAT6 (first part of bi-phasic pattern), and 

4) 3DAT6 through 35DAT6 (second part of bi-phasic pattern). The Registrant’s calculated halflives for these intervals, respectively, were 5.7 days (R2

 = 0.659), 3.4 days (R2 = 0.723), 16 hours 

(R2

 = 0.924), and 10.8 days (R2 = 0.731). 

EPA first assumed first-order dissipation kinetics and conducted a linear regression analysis 

using the corrected average DFRs from immediately after the last application (0DAT6) through 

the last sampling interval (35DAT6), and determined a half-life of 5.7 days (R2 = 0.6694). 

However, the regression analysis did not appear visually to be a good fit for the data, and a 

comparison of the 0DAT6 actual and predicted DFRs show that the actual DFR (1.74 μg/cm2

) is 

~4x higher than the linear regression predicted DFR (0.2005 μg/cm2). Therefore, EPA did 

additional analysis and conducted a biphasic (“hockey stick”) regression analysis using Excel’s 

Solver, and the corrected average DFRs from immediately after the last application through the 

last sampling interval. This regression analysis appears (visually) to be a better fit of the data, 

and provides a predicted Day 0 value of 2.4 μg/cm2. 

III DISCUSSION:

There were two issues noted in the review of the study. One was with regard to the field 

fortification recoveries. It was noted that (1) only one field fortification level was used; the EPA 

guideline recommends a minimum of two field fortification levels; (2) the level chosen was 

Page 88 of 95 Page 88 of 95
Page 14 of 20 

below many of the field samples (11.3 ug/sample for the field fortification samples vs a 

maximum of 1,300 ug/sample for the field samples); and (3) several recoveries were outside the 

guideline range of 70-120%. However, the study report did provide additional information with 

respect to laboratory recovery samples, which included a range of concentrations from 1.125 

ug/sample up to 1,125 ug/sample, with recoveries ranging from 92 – 134%; therefore, it is 

unlikely that the field fortification issues would impact the utility of the study for risk 

assessment. The other issue of note in the study is that profenofos residues were detected in the 

untreated control plot samples and in the blank field fortification samples at all sampling 

intervals except for the pre- and post- treatment 1 intervals. The profenofos levels were 1.58 to 

16.0 μg for the untreated control plot samples and 1.58 to 4.28 μg for the field fortification blank 

samples. 

 

Page 89 of 95 Page 89 of 95
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Table 4. DFRs for Cotton Leaves Treated with Profenofosa

Sampling 

Interval 

(days) 

Measured 

Residue 

(μg)b

DFR 

(μg/cm2)

c

Corrected 

DFR 

(μg/cm2)d

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application 

Rate 

Dislodgeablee

Pre 1 

<LOQ <0.0025 0.0013 

0.00125 0.000 0.000 -6.68 -- <LOQ <0.0025 0.0013 

<LOQ <0.0025 0.0013 

Post 1 

(0DAT1) 

1,300 3.25 2.88 

722 1.81 1.60 2.11 0.678 32.2 0.75 20.4 

835 2.09 1.85 

Pre 3 

(5DAT2) 

6.08 0.015 0.013 

4.50 0.011 0.010 0.012 0.002 17.5 -4.39 0.11 

6.30 0.016 0.014 

Post 3 

(0DAT3) 

833 2.08 1.84 

567 1.42 1.25 1.73 0.426 24.67 0.55 15.1 

941 2.35 2.08 

Pre 6 

(5DAT5) 

26.8 0.067 0.059 

28.6 0.072 0.063 0.054 0.012 22.7 -2.91 0.50 

18.2 0.046 0.040 

0DAT6 

1000 2.50 2.21 

655 1.638 1.45 1.74 0.411 23.5 0.56 16.0 

709 1.773 1.569 

1DAT 6 

156 0.390 0.345 

108 0.270 0.239 0.325 0.078 24.1 -1.12 3.0 

177 0.443 0.392 

2DAT6 

67.1 0.168 0.148 

36.5 0.091 0.081 0.109 0.035 32.5 -2.22 1.0 

43.9 0.110 0.097 

3DAT6 

47.9 0.120 0.106 

26.8 0.067 0.059 0.076 0.026 33.6 -2.57 0.70 

29.0 0.073 0.064 

7DAT6 

13.1 0.033 0.029 

11.7 0.029 0.026 0.026 0.003 12.9 -3.66 0.24 

10.1 0.025 0.022 

14DAT6 

4.73 0.012 0.010 

4.50 0.011 0.010 0.012 0.004 31.2 -4.39 0.11 

7.65 0.019 0.017 

21DAT6 

4.73 0.0118 0.010 

4.50 0.0113 0.010 0.0086 0.003 31.7 -4.75 0.08 

2.48 0.0062 0.0055 

28DAT6 

3.38 0.0085 0.007 

2.93 0.0073 0.006 0.0066 0.001 11.5 -5.01 0.06 

2.70 0.0068 0.006 

35DAT6 3.83 0.0096 0.0085 0.0086 0.001 8.9 -4.75 0.08 

Page 90 of 95 Page 90 of 95
Page 16 of 20 

Table 4. DFRs for Cotton Leaves Treated with Profenofosa

Sampling 

Interval 

(days) 

Measured 

Residue 

(μg)b

DFR 

(μg/cm2)

c

Corrected 

DFR 

(μg/cm2)d

Arithmetic 

Mean 

(μg/cm2) 

Standard 

Deviation 

(μg/cm2) 

Coefficient 

of Variance 

(%) 

Natural 

Log of 

Mean 

(μg/cm2) 

Percent of 

Application 

Rate 

Dislodgeablee

4.28 0.0107 0.0095 

3.60 0.0090 0.0080 

a. Six applications were made at a rate of 0.92-1.02 lb ai/A/application (approx. 10.3 -11.4 μg/cm2). 

b. LOQ = 0.003 μg/cm2; LOD was not reported. 

c. DFR = Measured residue (μg) / leaf surface area (400 cm2) 

d. DFR values were corrected for the average field fortification recovery (113%). For statistical calculations, residues 

<LOQ were assigned a value of 1⁄2 LOQ. 

e. Percent of Original Application Rate Dislodgeable = DFR (μg/cm2) / Amount applied (μg/cm2) x 100%. 

 

Page 91 of 95 Page 91 of 95
Page 17 of 20 

Appendix A. First Order Kinetics Regression 

Study Summary 

MRID 42851304 

Crop Cotton 

Region/State Region 6/Texas 

Application Rate (lb ai/acre) 1 

Dislodgeable Foliar Residue (DFR) Analysis 

Re-entry Day 

(Day After Treatment) 

Measured DFR (ug/cm2

) 

Individual Samples Average Standard Deviation 

0.000 

2.2124 

1.4491 1.74 0.4106 

1.5686 

1.00 

0.3451 

0.2389 0.325 0.0783 

0.3916 

2 

0.1485 

0.0808 0.109 0.0353 

0.0971 

3 

0.1060 

0.0593 0.076 0.0257 

0.0642 

7 

0.0290 

0.0259 0.0257 0.0033 

0.0223 

14 

0.0105 

0.0100 0.0124 0.0039 

0.0169 

21 

0.0105 

0.0100 0.0086 0.0027 

0.0055 

28 

0.0075 

0.0065 0.0066 0.0008 

0.0060 

35 

0.0085 

0.0095 0.0086 0.0008 

0.0080 

EPA/OPP/HED 1st Order Kinetics 

DAT ln(DFR) Modeled (ln DFR) Modeled DFR 

0.00 0.556 -1.607 0.200 

1.00 -1.123 -1.728 0.178 

2 -2.218 -1.850 0.157 

3 -2.571 -1.971 0.139 

7 -3.660 -2.456 0.086 

Page 92 of 95 Page 92 of 95
Page 18 of 20 

14 -4.386 -3.304 0.037 

21 -4.752 -4.153 0.016 

28 -5.014 -5.001 0.007 

35 -4.752 -5.850 0.003 

Residue Dissipation 

Decay constant (k) -0.121 

Daily Dissipation (%) 11% 

Half-life (days) 5.7 

Initial Residue 

C0 (ug/cm2

) 0.2005 

% of application rate 1.79% 

 

Page 93 of 95 Page 93 of 95
Page 19 of 20 

 

y = -0.1212x - 1.6072

R2 = 0.6694

-7.000

-6.000

-5.000

-4.000

-3.000

-2.000

-1.000

0.000

1.000

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

ln DFR (ug/cm2)

DAT

ln DFR vs. DAT

Page 94 of 95 Page 94 of 95
Page 20 of 20 

Appendix B. Biphasic (“Hockey Stick”) Regression 

"Hockey Stick" 

(untransformed residuals) 

Modeled DFR Squared Residuals 

1.74 0.22

1.74 0.09

1.74 0.03

0.33 0.00

0.33 0.01

0.33 0.00

0.11 0.00

0.11 0.00

0.11 0.00

0.08 0.00

0.08 0.00

0.08 0.00

0.03 0.00

0.03 0.00

0.03 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

Sum of Squared Errors (SSE) 0.35

C0 (ug/cm2) 2.4

C0: % of application rate 23%

Decay constant 1 (k1) -2.015

Decay constant 2 (k2) -0.272

Inflection Point (day) 1

Page 95 of 95 Page 95 of 95