Label
                                     4,120
                                     Label
                                     2.58

                                     0.01
                                   lb ai/gal

                                   0.0000619
                                    48,000
                                     Label
                                   0.000013

                                      330

                                  Foundations
                                  /perimeter
                                     Label
                                     4,120
                                     Label
                                     2.58
                                0.04 lb ai/gal

                                    0.00025
                                    12,000
                                     Label
                                   0.000052

                                      81

                      Aquatic areas (lakes, ponds, etc.)

        Structural (e.g., bridges, shipyards, home decks, foundations)
                                     Label
                                     1600
                                     Label
                                      30
                                     0.01
                                   lb ai/gal

                                   0.000024
                                    130,000
                                     Label
                                    0.00015

                                      28

                Industrial/commercial (tires, rail/junk yards)

                                  Mitigation
                                      PF5
                                    0.00003
                                      140

                         Manually-pressurized Handwand

   Greenhouse (ornamentals, roses, cut flowers, container stock, vegetables)
                                     Label
                                      365
                                     Label
                                      30
                                0.01 lb ai/gal
                                    40 gal
                                   0.0000055
                                    550,000
                                     Label
                                    0.00015
                                      28

           Landscaping, turf, (lawns, athletic fields, parks, etc.)

                              Indst./commercial
                               Foundations/Prmtr

                                  Mitigation
                                      PF5
                                    0.00003
                                      140

               Structural (bridges, shipyards, home decks, etc)

                       Mechanically-pressurized Handgun

                       Mechanically-pressurized Handgun

                               Orchard/Vineyard
                         Drench/Soil-Ground-directed,
                    Indst./commercial,  Field crop, typical
                                     Label
                                     1,360

                                     Label
                                     8.68

                                0.01 lb ai/gal

                                0.01 lb ai/gal

                                   1000 gal

                                   1000 gal

                                    0.00051

                                     5,900

                                     Label
                                    0.00109

                                      3.9

                                  Mitigation
                                     PF 5
                                     1.74

                                  Mitigation
                                     PF 5
                                   0.000218
                                      19

                                  Mitigation
                                     PF 10
                                     0.87

                                  Mitigation
                                     PF 10
                                    0.00011
                                      39

   Greenhouse (ornamentals, roses, cut flowers, container stock, vegetables)
                         Drench/Soil-/Ground-directed
                                     Label
                                     1,600
                                     Label
                                      120

                                    0.00060
                                     5,000
                                     Label
                                     0.015
                                     0.28

                                  Mitigation
                                     PF 5
                                      24

                                  Mitigation
                                     PF 5
                                     0.003
                                      1.4

                                  Mitigation
                                     PF 10
                                      12

                                  Mitigation
                                     PF 10
                                    0.0015
                                      2.8

                     Golf course, (tees fairways, greens)
                                     Label
                                      450
                                     Label
                                      1.9
                                0.5 lb ai/Acre
                                    5 acres
                                   0.000042
    71,000
                                     Label
                                   0.0000594
                                      71

            Landscaping, turf (lawns, athletic fields, parks, etc.)

1	Based on the "Occupational Pesticide Handler Unit Exposure Surrogate Reference Table" (September. 2015); Mitigation: Level of PPE above what is currently required on the labels needed to achieve a MOE = 30 for inhalation exposure.  The diquat dibromide product labels direct mixers, loaders, applicators and other handlers to wear long-sleeved shirt and long pants, coveralls, shoes  plus socks, chemical-resistant gloves and protective eyewear such as goggles or face shield, chemical-resistant headgear for overhead exposure, chemical resistant apron when cleaning equipment and  no respirator. However, sewer line treatments call for a dust/mist respirator as well.
2	Based on Table 4.1
3	Exposure Science Advisory Council Policy #9.0., Draft Occupational Aquatic Assumptions: July 2015 and the Aquatic SOP: November 2015.  Aquatic scenario inputs based on personal communication with Kurt Getsinger, U.S. Army Engineer R&D Center (July 25, 2016).
4	Dermal Dose = Dermal Unit Exposure (μg/lb ai) x Conversion Factor (0.001 mg/μg) x Application Rate (lb ai/acre or gal) x Area Treated or Amount  Handled Daily (A or gal/day) x DAF (0.3 %) / BW (80 kg).
5	Dermal MOE = Dermal NOAEL (3 mg/kg/day) / Dermal Dose (mg/kg/day).
6	Inhalation Dose = Inhalation Unit Exposure (μg/lb ai) x Conversion Factor (0.001 mg/μg) x Application Rate (lb ai/acre or gal) x Area Treated or Amount  Handled Daily (A or gal/day) / BW (80 kg).
7	Inhalation MOE = Inhalation human equivalent dose (0.0042 mg/kg/day) / Inhalation Dose (mg/kg/day).
8. Field Crop/Typical: Carrots, Coriander, Radishes, Spinach, Sugar beets, Table Beets, Turnips, Calendula, Tomato Vines, Cantaloupe Vines, Cucumbers, Squash, Watermelon Vines, Acorn Squash, Peppers, Eggplant, Green Pepper, Tomato, Green Peppers, Tomatoes
9.  The maximum single application rate of 4 lb ai/Acre/1 ft. for aerial applications is the most conservative aquatic (floating and marginal weeds) use rate. Based on the conversation with PRD and BEAD (7.28.2016), updates were made to the occupational scenarios for the aquatic uses:   Aquatic areas (Submersed Weeds) area treated = 210 acre-feet, and for Aquatic areas (Surface Weeds) area treated = 56 acre-feet (8 acres and 7 foot depth) based on the info from the US Army Corps of Engineers.
10. Label (EPA Reg. No. 64898-8;Razorooter II(TM)) notes that applications for spraying into sewer pipes consists of inserting a hose "downstream," then retracting the hose while turned on or spraying. Therefore, an applicator exposure scenario was not assessed.  For the amount of gallons approximated, see Memorandum, DP # 357118 titled, Metam Sodium: Third Revision of the HED Human Risk Assessment, Dated April 30, 2009.

6.2	Occupational Post-application Exposure/Risk Estimates

HED uses the term post-application to describe exposures that occur when individuals are present in an environment that has been previously treated with a pesticide (also referred to as re-entry exposure).  Such exposures may occur when workers enter previously treated areas to perform job functions, including activities related to crop production, such as scouting for pests or harvesting.  In the case of post-harvest treatment, post application activities include sorting and packing the treated crop. Post-application exposure levels vary over time and depend on such things as the type of activity, the nature of the crop or target that was treated, the type of pesticide application, and the chemical's degradation properties.

6.2.1	Occupational Post-application Inhalation Exposure / Risk Estimates

Occupational Post-application Inhalation Exposure Data and Assumptions
There are multiple potential sources of post-application inhalation exposure to individuals performing post-application activities in previously treated fields. These potential sources include volatilization of pesticides and re-suspension of dusts and/or particulates that contain pesticides.  The agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html).  The agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a subsequent Volatilization Screening Analysis (http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219).  During Registration Review, the agency will utilize this analysis to determine if data (i.e., flux studies, route-specific inhalation toxicological studies) or further analysis is required for diquat dibromide.

In addition, the Agency is continuing to evaluate the available post-application inhalation exposure data generated by the Agricultural Reentry Task Force.  Given these two efforts, the Agency will continue to identify the need for and, subsequently, the way to incorporate occupational post-application inhalation exposure into the agency's risk assessments.

6.2.2	Occupational Post-application Dermal Exposure/Risk Estimates

Occupational Post-application Dermal Exposure Data and Assumptions
HED believes that due to the nature of the chemical (herbicide) and the exposure scenarios; pre-, and post-harvest desiccant/de-foliar; ground directed spray for the control of weeds and aquatic uses, a quantitative occupational post-application dermal exposure assessment was not warranted for these uses. However, a dermal post-application assessment was completed for the registered golf course turf uses to cover exposure from workers performing maintenance to golf courses post turf applications.

A series of assumptions and exposure factors served as the basis for completing the occupational post-application risk assessments.  Each assumption and factor is detailed below on an individual basis.

Exposure Duration:
HED classifies exposures from 1 to 30 days as short-term and exposures 30 days to six months as intermediate-term. For diquat dibromide, based on the proposed use, dermal exposure due to applications to golf course turf are expected for the following reasons:  (1) Post turf applications, workers will be conducting maintenance to fairways and greens. Due to the maximum number of applications per year (3), HED believes that the exposure will be short-term in nature. However, due to the short-, and intermediate-term PODs being the same, an intermediate assessment was included.

Transfer Coefficients:
It is the policy of HED to use the best available data to assess post-application exposure.  Sources of generic post-application data, used as surrogate data in the absence of chemical-specific data, are derived from ARTF exposure monitoring studies, and, as proprietary data, are subject to the data protection provisions of FIFRA.  The standard values recommended for use in predicting post-application exposure that are used in this assessment, known as "transfer coefficients",  are presented in the ExpoSAC Policy 3" which, along with additional information about the ARTF data, can be found at the Agency website.  Table <IP_ADDRESS> provides a summary of the anticipated post-application activities and associated transfer coefficients for the proposed crops/use sites

Table <IP_ADDRESS>.  Anticipated Post-Application Activities and Dermal Transfer Coefficients.
                                Proposed Crops
                          Policy Crop Group Category
                                  Crop Height
                                Foliage Density
                       Transfer Coefficients (cm[2]/hr)
                                  Activities
                                  Golf course
                                  Turf/sod[1]
                                      low
                                     full
                                     3700
                                  Maintenance

                                     2500
                            Maintenance/greens only
1. No crop category is assigned for turf/sod

Application Rate:
See the use profile table 4.1 for details.

Exposure Time:
The average occupational workday is assumed to be 8 hours.

Dislodgeable Foliar Residues:
Chemical-specific dislodgeable foliar residue "turf" data has been submitted for diquat dibromide. However, the Modified California Roller method was not used for data gathering, therefore, this assessment uses HED's default assumption that 1% of the application is available for transfer on day 0 following the application and the residues dissipate at a rate of 10% each following day.

Occupational Post-application Non-Cancer Dermal Exposure and Risk Estimate Equations
The algorithms used to estimate non-cancer exposure and dose for occupational post-application workers can be found in Appendix A.

Occupational Post-application Non-Cancer Dermal Risk Estimates

Table <IP_ADDRESS>.  Occupational Post-application Non-Cancer Exposure and Risk Estimates for Diquat Dibromide.
                                   Crop/Site
                                  Activities
                        Transfer Coefficient (cm[2]/hr)
                                  DFR/TTR[1]
                                 Dermal Dose
                                (mg/kg/day)[2]
                                    MOE[3]
                         Short-term/ Intermediate-term
                                     Turf:

                                  Golf Course
                                  Maintenance
                                     3700
                                     0.056

                                     0.056
                                   0.000062
                                    48,000

                            Maintenance/greens only
                                     2500

                                   0.000042
                                    71,000
1	TTR = Application Rate x F x (1-D)t x 4.54E8 ug/lb x 2.47E-8 acre/cm[2]; where F = 0.1 and D = 0.10 per
2	Daily Dermal Dose = [DFR (ug/cm[2]) x Transfer Coefficient x 0.001 mg/ug x 8 hrs/day x dermal absorption (0.3 %)]  BW (80 kg).
3	MOE = POD (mg/kg/day) / Daily Dermal Dose.  Daily Dermal Dose = [DFR/TTR (ug/cm[2]) x TC x 0.001 mg/ug x 8 hrs/day x dermal absorption factor (0.3 %)]  BW (80 kg).

Restricted Entry Interval
Diquat dibromide is classified as Acute Toxicity Categories II or III via the oral, dermal, and inhalation routes.  . Diquat dibromide is not an acute skin irritant (Toxicity Category IV) nor a dermal sensitizer, but it is considered a moderate-to-severe eye irritant (Toxicity Category II).  Short- and intermediate-term post-application risk estimates were not a concern on day 0 (12 hours following application) for all post-application activities. The current product labels recommend a 24-hour REI.

Appendix A.  Summary of Residential and Occupational and Non-cancer Algorithms

 Residential Handlers Dermal and Inhalation Handler Exposure Algorithm
1.1	Turf, Gardens and Trees, Indoor Environments
Daily dermal and inhalation exposure (mg/day) for residential pesticide handlers, for a given formulation-application method combination, is estimated by multiplying the formulation-application method-specific unit exposure by an estimate of the amount of active ingredient handled in a day, using the equation below:

                                E = UE * AR * A
Where:

E 	= exposure (mg/day);
UE 	= unit exposure (mg/lb ai);
AR 	= application rate (e.g., lb ai/ft[2], lb ai/gal); and
A 	= area treated or amount handled (e.g., ft[2]/day, gal/day).

1.2	Residential Handler Dose Calculations

Dermal and/or inhalation absorbed doses normalized to body weight are calculated as:

                                D = E *AF / BW
Where:

D 	= dose (mg/kg-day);
E 	= exposure (mg/day);
AF 	= absorption factor (dermal and/or inhalation); and
BW	 = body weight (kg).

2.0	Residential Non-cancer Post-application Algorithms
2.1	Turf/Physical Activities on Turf

Post-application Dermal Exposure Algorithm  -  Physical Activities on Turf
Exposure resulting from contacting previously treated turf while performing physical activities is calculated as shown below.  Residential post-application exposure assessment must include calculation of exposure on the day of application.  Therefore, though an assessment can present exposures for any day "t" following the application, it must include "day 0" exposure.

                           E = TTRt * CF1 * TC * ET
Where:

E 	= exposure (mg/day);
TTRt 	= turf transferable residue on day t (μg/cm[2]);
CF1 	= weight unit conversion factor (0.001 mg/μg);
TC	 = transfer coefficient (cm[2]/hr); and
ET	 = exposure time (hr/day).

If chemical-specific TTR data are available, then surface residues from the day of application should be used (assume that individuals could be exposed to residues immediately after application). However, if data are not available, then TTRt can be calculated using the following formula:

                      TTRt= AR * F * (1-FD)t * CF2 * CF3
Where:

TTRt 	= turf transferable residue on day t (μg/cm[2]);
AR 	= application rate (lbs ai/ft[2] or lb ai/acre);
F 	= fraction of ai as transferable residue following application (unitless);
FD 	= fraction of residue that dissipates daily (unitless);
t 	= post-application day on which exposure is being assessed;
CF2	= weight unit conversion factor (4.54 x 10[8] μg/lb); and
CF3 	= area unit conversion factor (1.08 x 10[-3] ft[2]/ cm[2] or 2.47 x 10[-8] acre/cm[2]).

Dermal absorbed doses are calculated as:

Where:

D	= dose (mg/kg-day);
E	= exposure (mg/day);
AF	= absorption factor (dermal); and
BW	= body weight (kg).

Turf (Physical Activities) -- Inputs for Residential Post-application Dermal Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      AR
                               Application rate
                    (mass active ingredient per unit area)
                                    [input]
                                       F
Fraction of AR as TTR following application (if chemical-specific data is unavailable)
                                   L/WP/WDG
                                     0.01

                                   Granules
                                     0.002
                                      FD
     Daily residue dissipation (if chemical-specific data is unavailable)
                                  (fraction)
                                   L/WP/WDG
                                      0.1

                                   Granules
                                      0.1
                                      TC
                        Transfer Coefficient (cm[2]/hr)
                                   L/WP/WDG
                                    Adults
                                    180,000

                          Children 1 < 2 years old
                                    49,000

                                   Granules
                                    Adults
                                    200,000

                          Children 1 < 2 years old
                                    54,000
                                      ET
                                 Exposure Time
                                (hours per day)
                                    Adults
                                      1.5

                          Children 1 < 2 years old
                                      1.5
                                      BW
                                  Body Weight
                                     (kg)
                                    Adults
                                      80

                          Children 1 < 2 years old
                                      11
L/WP/WDG = Liquids/Wettable Powders/Water-dispersible Granules

Post-application Hand-to-Mouth Exposure Algorithm -  Physical Activities on Turf
Exposure from hand-to-mouth activity is calculated as follows (based on the algorithm utilized in the SHEDS-Multimedia model):

  E = [HR * (FM * SAH) * (ET * N_Replen) * (1- (1- SE)[(Freq_HtM/N-Replen)])]
Where:

E 	= exposure (mg/day);
HR	 = hand residue loading (mg/cm[2]);
FM 	= fraction hand surface area mouthed / event (fraction/event);
SAH 	= typical surface area of one hand (cm[2]);
ET 	= exposure time (hr/day);
N_Replen = number of replenishment intervals per hour (intervals/hour);
SE 	= saliva extraction factor (i.e., mouthing removal efficiency); and
Freq_HtM = number of hand-to-mouth contacts events per hour (events/hour).

Where:

HR 	= hand residue loading (mg/cm[2]);
Faihands	= fraction ai on hands compared to total surface residue from dermal transfer coefficient                study (unitless);
DE 	= dermal exposure (mg); and
SAH	= typical surface area of one hand (cm[2]).

Dose, normalized to body weight, is calculated as:

Where:
D	= dose (mg/kg-day);
E	= exposure (mg/day); and
BW	= body weight (kg).

Turf (Physical Activities)  -  Inputs for Residential Post-application Hand-to-Mouth Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                   Faihands
        Fraction of ai on hands from dermal transfer coefficient study
                                  (unitless)
                              Liquid formulations
                                     0.06

                             Granular formulations
                                     0.027
                                      DE
                             Dermal exposure (mg)
                                  Calculated
                                      SAH
     Typical surface area of one hand (cm[2]), children 1 < 2 years old
                                      150
                                      AR
                               Application rate
                    (mass active ingredient per unit area)
                                    [input]
                                      HR
                   Residue available on the hands (mg/cm[2])
                      Calculated via (DE * Faihands)/SAH
                                      FM
                      Fraction hand surface area mouthed
                               (fraction/event)
                                     0.127
                                   N_Replen
                       Replenishment intervals per hour
                                (intervals/hr)
                                       4
                                      ET
                                Exposure time
                                   (hrs/day)
                                      1.5
                                      SE
                           Saliva extraction factor
                                  (unitless)
                                     0.48
                                   Freq_HtM
                         Hand-to-mouth events per hour
                                  (events/hr)
                                     13.9
                                      BW
                                  Body Weight
                                     (kg)
                          Children 1 < 2 years old
                                      11

Post-application Object-to-Mouth Exposure Algorithm -  Physical Activities on Turf
Exposure from object-to-mouth activity is calculated as follows (based on the algorithm utilized in SHEDS-Multimedia):

	E = [OR* CF1 * SAMO * (ET * N_Replen) * (1- (1- SEO)(Freq_OtM/N_Replen))]

Where:

E	= exposure (mg/day);
OR	= chemical residue loading on the object on day "t" (ug/cm[2]);
CF1 	= weight unit conversion factor (0.001 mg/ug);
SAMO 	= area of the object surface that is mouthed (cm[2]/event);
ET 	= exposure time (hr/day);
N_Replen = number of replenishment intervals per hour (intervals/hour);
SEO  	= saliva extraction factor (i.e., mouthing removal efficiency); and
Freq_OtM  = number of object-to-mouth contact events per hour (events/hour).

	OR = AR * FO * CF2 * CF3
Where:

OR 	= chemical residue loading on the object (μg/cm[2]);
AR 	= application rate (lbs ai/ft[2] or lb ai/acre);
FO 	= fraction of residue available on the object (unitless);
CF2 	= weight unit conversion factor (4.54 x 10[8] ug/lb); and
CF3 	= area unit conversion factor (1.08 x 10[-3] ft[2]/cm[2] or 2.47 x 10[-8] acre/cm[2]).

Dose, normalized to body weight, is calculated as:

Where:
D	=	dose (mg/kg-day);
E	= exposure (mg/day); and
BW	= body weight (kg).

Turf (Physical Activities)  -  Inputs for Residential Post-application Object-to-Mouth Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      AR
                          Application rate (to turf)
                    (mass active ingredient per unit area)
                                    [input]
                                      FO
                Fraction of AR as OR following application [1]
                                     0.01
                                     SAMO
                        Surface area of object mouthed
                                 (cm[2]/event)
                                      10
                                   N_Replen
               Replenishment intervals per hour (intervals/hour)
                                       4
                                      SEO
                           Saliva extraction factor
                                  (fraction)
                                     0.48
                                      ET
                                Exposure time
                                (hours per day)
                                      1.5
                                   Freq_OtM
                  Object-to-mouth events per hour (events/hr)
                                      8.8
                                      BW
                               Body Weight (kg)
                          Children 1 < 2 years old
                                      11
1 This SOP assumes that all of the residue on the turf could be transferred to the object (e.g., object residue is equal to turf transferable residue).

Post-application Incidental Soil Ingestion Exposure Algorithm -  Physical Activities on Turf
Exposure from incidental soil ingestion is calculated as follows:

	E = SRt * SIgR * CF1
Where:

E 	= exposure (mg/day);
SRt	= soil residue on day "t" (ug/g);
SIgR	= ingestion rate of soil (mg/day); and
CF1 	= weight unit conversion factor (1 x 10[-6] g/ug).

	SRt = AR * FS * (1-FD)t * CF2 * CF3 * CF4
Where:

SRt 	= soil residue on day "t" (ug/g);
AR 	= application rate (lbs ai/ft[2] or lb ai/acre);
FS 	= fraction of ai available in uppermost cm of soil (fraction/cm);
FD	 = fraction of residue that dissipates daily (unitless);
T 	= post-application day on which exposure is being assessed;
CF2	= weight unit conversion factor (4.54 x 10[8] ug/lb);
CF3 	= area unit conversion factor (1.08 x 10[-3] ft[2]/cm2 or 2.47 x 10[-8] acre/cm[2]); and
CF4	 = soil volume to weight unit conversion factor (0.67 cm[3]/g soil).

Dose, normalized to body weight, are calculated as:

Where:
D	= dose (mg/kg-day);
E	= exposure (mg/day); and
BW	= body weight (kg).

Turf (Physical Activities)  -  Inputs for Residential Post-application Incidental Soil Ingestion Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      AR
                               Application rate
                    (mass active ingredient per unit area)
                                    [input]
                                      FS
              Fraction of AR available in uppermost 1 cm of soil
                                  (unitless)
                                       1
                                      FD
                           Daily residue dissipation
                                  (fraction)
                                      0.1
                                     SIgR
                         Soil ingestion rate (mg/day)
                                      50
                                      BW
                               Body weight (kg)
                          Children 1 < 2 years old
                                      11

Post-application Episodic Granular Ingestion Exposure Algorithm -  Physical Activities on Turf
Exposure from incidental ingestion of pesticide pellets or granules is calculated as follows:

               	                     		E = GIgR* FD * CF1
Where:

E 	= exposure (mg/day);
GIgR 	= ingestion rate of dry pesticide formulation (g/day);
FD 	= fraction of ai in dry formulation (unitless); and
CF1 	= weight unit conversion factor (1,000 mg/g).

Dose, normalized to body weight, are calculated as:

Where:
D	= dose (mg/kg-day);
E	= exposure (mg/day); and
BW	= body weight (kg).
2.2	Turf/Mowing

Post-application Dermal Exposure Algorithm  -  Mowing
Exposure resulting from contacting previously treated turf while mowing is calculated as follows:

	E = TTRt * CF1 * TC * ET
Where:

E 	= exposure (mg/day);
TTRt  	= turf transferable residue on day "t" (ug/cm[2]);
CF1	 = weight unit conversion factor (0.001 mg/ug);
TC  	= transfer coefficient (cm[2]/hr); and
ET  	= exposure time (hr/day).

	TTRt = AR * FAR * (1-FD)t * CF2 * CF3
Where:

TTRt  	= turf transferable residue on day "t" (ug/cm[2]);
AR 	= application rate (lbs ai/ft[2] or lb ai/acre);
FAR	= fraction of ai retained on turf (unitless);
FD 	= fraction of residue that dissipates daily (unitless);
T	= post-application day on which exposure is being assessed;
CF2	= weight unit conversion factor (4.54 x 10[8] ug/lb); and
CF3 	= area unit conversion factor (1.08 x 10[-3] ft[2]/cm[2] or 2.47 x 10[-8] acre/cm[2]).

Absorbed dose, normalized to body weight, are calculated as:

Where:
D	= dose (mg/kg-day);
E	= exposure (mg/day);
AF	= absorption factor (dermal); and
BW	= body weight (kg).

Turf (Mowing)  -  Inputs for Residential Post-application Dermal Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      AR
                               Application rate
                     mass active ingredient per unit area
                                    [input]
                                      FAR
                  Fraction of AR as TTR following application
                                   L/WP/WDG
                                     0.01

                                   Granules
                                     0.002
                                      FD
                           Daily residue dissipation
                                   L/WP/WDG
                                      0.1

                                   Granules
                                      0.1
                                      TC
                             Transfer Coefficient
                                  (cm[2]/hr)
                                     Adult
                                     5,500

                         Children 11 < 16 years old
                                     4,500
                                      ET
                                Exposure time
                                (hours per day)
                                       1
                                      BW
                                 Body Weight
                                     (kg)
                                    Adults
                                      80

                         Children 11 < 16 years old
                                      57
L/WP/WDG = liquid/wettable powder/water dispersible granule

2.3	Turf/Golfing

Post-application Dermal Exposure Algorithm  -  Golfing
Exposure resulting from contacting previously treated turf while golfing is calculated as follows:

	E = TTRt * CF1 * TC * ET
Where:

E	= exposure (mg/day);
TTRt 	= turf transferable residue on day "t" (ug/cm[2]);
CF1	= weight unit conversion factor (0.001 mg/ug);
TC	= transfer coefficient (cm[2]/hr); and
ET 	= exposure time (hr/day).

	TTRt = AR * F * (1-FD)t * CF2 * CF3
Where:

TTRt	= turf transferable residue on day "t" (ug/cm[2]);
AR 	= application rate (lbs ai/ft[2] or lb ai/acre);
F 	= fraction of ai retained on turf (unitless);'
FD 	= fraction of residue that dissipates daily (unitless);
T	= post-application day on which exposure is being assessed;
CF2	= weight unit conversion factor (4.54 x 10[8] ug/lb); and
CF3 	= area unit conversion factor (1.08 x 10[-3] ft[2]/cm[2] or 2.47 x 10[-8] acre/cm[2]).

Absorbed dose, normalized to body weight, is calculated as:

Where:
D	= dose (mg/kg-day);
E	= exposure (mg/day);
AF	= absorption factor (dermal); and
BW	= body weight (kg).

Turf (Golfing)  -  Inputs for Residential Post-application Dermal Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)

                                      AR
                               Application rate
                    (mass active ingredient per unit area)
                                    [input]
                                       F
                  Fraction of AR as TTR following application
                                   L/WP/WDG
                                     0.01

                                   Granules
                                     0.002
                                      FD
                           Daily residue dissipation
                                   L/WP/WDG
                                      0.1

                                   Granules
                                      0.1
                                      TC
                             Transfer Coefficient
                                  (cm[2]/hr)
                                     Adult
                                     5,300

                         Children 11 < 16 years old
                                     4,400

                         Children 6 < 11 years old
                                     2,900
                                      ET
                                 Exposure time
                                (hours per day)
                Pesticides used on greens, tees, and fairways
                                       4

                    Pesticides used only on greens and tees
                                       1
                                      BW
                                  Body Weight
                                     (kg)
                                    Adults
                                      80

                         Children 11 < 16 years old
                                      57

                         Children 6 < 11 years old
                                      32
NA = not applicable
L/WP/WDG = liquid/wettable powder/water dispersible granule

2.4	Gardens and Trees

Post-application Dermal Exposure Algorithm
Exposure resulting from contacting previously treated gardens and trees while performing physical activities is calculated as shown below.  Residential post-application exposure assessment must include calculation of exposure on the day of application.  Therefore, though an assessment can present exposures for any day "t" following the application, it must include "day 0" exposure.
	E = DFRt * CF1 * TC * ET

Where:

E 	= exposure (mg/day);
DFRt 	= dislodgeable foliar residue on day "t" (ug/cm[2]);
CF1	= weight unit conversion factor (0.001 mg/ug);
TC	= transfer coefficient (cm[2]/hr); and
ET 	= exposure time (hrs/day).

In the absence of chemical-specific data, DFRt can be calculated as follows:

	DFRt = AR * FAR * (1-FD)t * CF2 * CF3
Where:

DFRt 	= dislodgeable foliar residue on day "t" (ug/cm[2]);
AR	= application rate (lbs ai/ft[2] or lb ai/acre);
FAR	= fraction of ai as dislodgeable residue following application (unitless);
FD 	= fraction of residue that dissipates daily (unitless);
T	= post-application day on which exposure is being assessed;
CF2 	= weight unit conversion factor (4.54 x 10[8] ug/lb); and
CF3	= area unit conversion factor (1.08 x 10[-3] ft[2]/cm[2] or 2.47 x 10[-8] acre/cm[2]).

Absorbed dermal dose, normalized to body weight, is calculated as:

Where:

D	= dose (mg/kg-day);
E	= exposure (mg/day);
AF	= absorption factor (dermal and/or inhalation); and
BW	= body weight (kg).

Gardens, Trees, and "Pick-your-own" Farms  - Inputs for Residential Post-application Dermal Exposure
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)

                                      AR
                   Application rate (mass ai per unit area)
                                    [input]
                                      FAR
   DFR following application, if chemical-specific is unavailable (fraction)
                                     0.25
                                      FD
   Daily residue dissipation, if chemical-specific is unavailable (fraction)
                                     0.10
                                      TC
                             Transfer Coefficient
                                  (cm[2]/hr)
                                  Gardens[a]
                                    Adults
                                     8400

                         Children 6 < 11 years old
                                     4600

                    Trees, Retail Plants (if applicable)[a]
                                    Adults
                                     1700

                         Children 6 < 11 years old
                                      930

                                 Indoor Plants
                                    Adults
                                      220

                         Children 6 < 11 years old
                                      120
                                      ET
                                 Exposure Time
                                (hours per day)
                              Home activities[b]
                                    Gardens
                                    Adults
                                      2.2

                         Children 6 < 11 years old
                                      1.1

                     Trees, Retail Plants (if applicable)
                                    Adults
                                      1.0

                         Children 6 < 11 years old
                                     0.50

                                 Indoor Plants
                                    Adults
                                      1.0

                         Children 6 < 11 years old
                                     0.50

                   "Pick-your-own" Farms (if applicable)
                                    Adults
                                      5.0

                         Children 6 < 11 years old
                                      1.9
                                      BW
                                  Body weight
                                     (kg)
                                    Adults
                                      80

                         Children 6 < 11 years old
                                      32
[a] Transfer coefficient point estimates from a composite distribution assuming equal proportion of time spent conducting various activities.  See "Transfer Coefficient" section below.  Children 6 < 11 years old TC derived using surface area adjustment (see Section 2.3).
[b] Activity time point estimates from a composite distribution assuming equal proportion of each respective activity.  Time for children 6 < 11 years old derived using hrs/day ratio adjustment.  See "Exposure Time" section below.
3.0	Occupational Handlers

Occupational Non-cancer Handler Algorithms

Potential daily exposures for occupational handlers are calculated using the following formulas:

E=UE * AR * A * 0.001 mg/ug
Where:

E	= exposure (mg ai/day),
UE	= unit exposure (ug ai/lb ai),
AR	= maximum application rate according to proposed label (lb ai A or lb ai/gal), and
A	= area treated or amount handled (e.g., A/day, gal/day).

The daily doses are calculated using the following formula:

ADD=  E * AFBW
Where:

ADD	= average daily dose absorbed in a given scenario (mg ai/kg/day),
E	= exposure (mg ai/day),
AF	= absorption factor (dermal and/or inhalation), and
BW 	= body weight (kg).

Margin of Exposure:  Non-cancer risk estimates for each application handler scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern.  The daily dermal and inhalation dose received by occupational handlers are compared to the appropriate POD (i.e., NOAEL) to assess the risk to occupational handlers for each exposure route.  All MOE values are calculated using the following formula:

MOE= PODADD

Where:

MOE	= margin of exposure: value used by HED to represent risk estimates (unitless),
POD	= point of departure (mg/kg/day), and
ADD	= average daily dose absorbed in a given scenario (mg ai/kg/day).

4.0	Occupational Post-Application

Occupational Non-cancer Post-application Algorithms

Potential daily exposures for occupational post-application workers are calculated using the following formulas:
DFRt=AR *  F* (1-D)t*4.54E8uglb*2.47E-8Acm2
Where:

DFRt	= dislodgeable foliage residue on day "t" (ug/cm[2]),
AR	= application rate (lb ai/acre),
F	= fraction of ai retained on foliage or 25% (unitless),
D	= fraction of residue that dissipates daily or 10% (unitless), and
t	= number of days after application day (days).

E=TC * DFR t * ET * 0.001mgug
Where:

E	= exposure (mg ai/day),
TC 	= transfer coefficient (cm[2]/hr),
DFRt	= dislodgeable foliar residue on day "t" (ug/cm[2]), and
ET	= exposure time (hours/day).

The daily doses are calculated using the following formula:

ADD=  E * AFBW
Where:

ADD	= average daily dose absorbed in a given scenario (mg ai/kg/day),
E	= exposure (mg ai/day),
AF	= absorption factor (dermal and/or inhalation), and
BW 	= body weight (kg).
Margin of Exposure:  Non-cancer risk estimates for each scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern.  The daily dermal dose received by occupational post-application workers is compared to the appropriate POD (i.e., NOAEL) to assess the risk to occupational post-application workers.  All MOE values are calculated using the following formula:
MOE= PODADD
Where:

MOE	= margin of exposure: value used by HED to represent risk estimates (unitless),
POD	= point of departure (mg/kg/day), and
ADD	= average daily dose absorbed in a given scenario (mg ai/kg/day).

5.0	Aquatic Use

The procedures outlined in this section should be used to assess residential dermal and inhalation exposure during (i.e., handler) and following (i.e., post-application) pesticide applications to aquatic areas, such as lakes and ponds by professional pesticide applicators or homeowners themselves.  Pesticides can also be used in pools and spas which can lead to both residential handler and post-application exposure.  The Antimicrobials Division (AD) of OPP has guidance and SOPs for assessing exposure from treated pools and spas, including the Swimmer Exposure Assessment Model (http://www.epa.gov/oppad001/swimodel.htm).

For pesticides that can be used in aquatic areas such as lakes and ponds, the exposure assessor should assume the product is permitted for use by homeowners unless:
 The product has a "Restricted Use Pesticide" classification, which indicates that the product cannot be bought or applied by homeowners (i.e., no residential handler exposure/risk assessment required).
 The label indicates that the product may only be applied to water by Federal or State agencies, U.S. Army Corps of Engineers, and licensed applicators authorized by Federal or State agencies.
 The labels indicate state and/or local authorities are to be consulted prior to applying this product in or around public waters.
 The labels state that prior to retreatment, samples should be collected and analyzed for parent concentration to establish the amount of product to apply.

In each of these cases, a residential handler assessment would not be necessary, but the product may be applied by commercial applicators to residential sites; therefore, a post-application risk assessment may be required.   The post-application section of this SOP typically will apply to situations where an application is made by commercial applicators to larger aquatic areas (e.g., lakes, ponds) where swimming would be expected to occur.  It is not anticipated that swimming would occur in aquatic areas typically assumed to be treated by homeowners, such as backyard ponds or fountains.  Once scenarios are identified, the assessment should then characterize and estimate the potential for exposure by route (e.g., dermal, inhalation, oral) using the methodologies outlined in this section.

In certain circumstances, it may be appropriate to assess dermal and incidental oral exposure to sediment (e.g., application of a pesticide to intertidal waters or oyster beds), however, this should not routinely be conducted for typical aquatic applications.  If such assessments are deemed necessary, the assessor should refer to recent example assessments such as those for imidacloprid (D400191) or carbaryl (D287251).

5.1	Handler Exposure Assessment

Handler exposure can result from treating aquatic sites in residential settings (e.g., backyard ponds or fountains) with pesticides.  Some key assumptions for these assessments include:

 Adults are considered the index lifestage for this scenario as it is assumed that pesticides are applied by adults only (i.e., individuals 16 years and older).
 All application equipment and methods are assumed feasible unless prohibited by the product label.

Dermal and Inhalation Handler Exposure Algorithm
As described, daily dermal and inhalation exposure (mg/day) for residential pesticide handlers, for a given formulation-application method combination, is estimated by multiplying the formulation-application method-specific unit exposure by an estimate of the amount of active ingredient handled in a day, using the equation below:

E=UE*AR*A*D
Where:

E	= exposure (mg/day);
UE	= unit exposure (mg/lb ai);
AR	= application rate (e.g., lb ai/ft2, lb ai/ft3, lb ai/A-ft);
A	= area treated (e.g., ft[2]/day, A/day); and
D	= depth of water body treated (ft).

NOTE:  The input for the depth of the water body treated is only applicable if the application rate is given per volume (i.e., lb ai/ft[3] or lb ai/A-ft).

Dermal and/or inhalation absorbed doses normalized to body weight are calculated as:

D= E*AFBW
Where:

D	= dose (mg/kg-day);
E	= exposure (mg/day);
AF	= absorption factor (dermal and/or inhalation); and
BW	= body weight (kg).

Handler exposure for applications to aquatic sites is generally considered short-term in duration.  Refinement of this dose estimate to reflect a more accurate short-term multi-day exposure profile can be accomplished by accounting for the various factors outlined in Section 5.0.,such as the product-specific application regimen.

Dermal and Inhalation Handler Exposure Algorithm Inputs and Assumptions
Recommended values for handler exposure (inhalation and dermal) assessments are provided in Table 6.1.  Following these tables, each scenario-specific input parameter is described in more detail.  This description includes a summary of i) key assumptions, ii) data sources used to derive recommended input values, and iii) discussion of limitations that should be addressed when characterizing exposure.

Aquatic Sites  -  Recommended Unit Exposure (mg/lb ai) Point Estimates.
                                  Formulation
                         Equipment/Application Method
                                    Dermal
                                  Inhalation
                            Appendix Page Reference

                                Point Estimate
                                Point Estimate

Granules
Spoon
                                      6.2
                                     0.087

Cup
                                     0.11
                                     0.013

Hand dispersal
                                      160
                                     0.38

Shaker can
No exposure data available for this application scenario.  Exposure data for granule applications using a cup recommended as surrogate data.
Liquid concentrates
Manually-pressurized handwand
                                      63
                                     0.018

Hose-end sprayer
                                      58
                                    0.0014

Backpack
                                      130
                                     0.14

Sprinkler can
No exposure data available for this application scenario.  Exposure data for hose-end sprayer applications of liquid concentrates recommended as surrogate data.
Wettable Powder
Manually-pressurized handwand
                                      69
                                      1.1

Hose-end sprayer
No exposure data available for this application scenario.  Exposure data for hose-end sprayer applications of liquid concentrates recommended as surrogate data.

Backpack
No exposure data available for this application scenario.  Exposure data for manually-pressurized handwand applications of wettable powders recommended as surrogate data.

Sprinkler can
No exposure data available for this application scenario.  Exposure data for hose-end sprayer applications of liquid concentrates recommended as surrogate data.
Wettable Powder in Water-soluble Packaging
Manually-pressurized handwand
No exposure data available for this scenario.  Exposure data for manually-pressurized handwand applications of liquid concentrates recommended as surrogate data.

Hose-end sprayer
No exposure data available for this scenario.  Exposure data for RTU hose-end sprayers recommended as surrogate data.

Backpack
No exposure data available for this scenario.  Exposure data for manually-pressurized handwand applications of liquid concentrates recommended as surrogate data.

Sprinkler can
No exposure data available for this scenario.  Exposure data for RTU hose-end sprayers recommended as surrogate data.
Dry Flowable / Water-dispersible Granule
Manually-pressurized handwand
No exposure data available for this scenario.  Application method-specific exposure data for wettable powders recommended as surrogate data.

Hose-end sprayer

Backpack

Sprinkler can

Dusts/Powders
Plunger duster
                                      250
                                      1.7
                                     C-32

Bulb duster
No exposure data available for this application scenario.
Exposure data for plunger duster applications recommended
as surrogate data.

Electric/power duster
No exposure data available for this application scenario.
Exposure data for shaker can applications of dusts/powders
recommended as surrogate data.

Hand crank duster
No exposure data available for this application scenario.
Exposure data for shaker can applications of dusts/powders
recommended as surrogate data.

Shaker can
                                     4300
                                      18
                                     C-36
Ready-to-Use (RTU)
Hose-end sprayer
                                     6.26
                                     0.034
                                     C-107
Micro-encapsulates
Manually-pressurized handwand
No exposure data available for this scenario.  Application method-specific exposure data for liquid concentrates recommended as surrogate data.

Hose-end sprayer

Backpack

Sprinkler can

Aquatic Sites  -  Recommended Residential Handler Exposure Factor Point Estimates.
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
Application Rate (mass ai per unit area or volume)
                             Maximum labeled rate
Area treated
Ornamental backyard pond
                                500 square feet

Recreational/fish pond
                                   10 acres
Depth of water body (ft)
Ornamental backyard pond
                                       2

Recreational/fish pond
                                       7
Body Weight (kg)
                                      80

Unit Exposures
The unit exposure is the ratio, for a given formulation/application method combination, between exposure and the amount of active ingredient handled, with units mass exposure per mass active ingredient handled (e.g., mg ai exposure/lb ai handled).

Amount of active ingredient Handled
The algorithm for estimating handler exposure requires some estimate of the amount of active ingredient handled per day. This factor varies based on the type of equipment or application method used and is estimated based on the application rate specified on the product label. First, the assessor should assemble application rate information in terms of active ingredient per area or volume treated (e.g., lb ai/acre, lb ai/1000 ft[2], lb ai/A-ft, lb ai/ft[3]).   Data on the amount of active ingredient handled are limited and difficult to collect. The amounts of active ingredient handled presented in this SOP are reasonable high-end assumptions for typical residential aquatic applications.

For residential homeowner applications to backyard or recreational ponds, information on the amount of product used or the area treated is largely unavailable.  Therefore, a general internet search was conducted and several assumptions have been made for this input factor.  Depending on the use sites noted on the label, the following are recommendations for area treated for residential aquatic use sites:
 500 square feet surface area and a 2 foot depth for ornamental backyard ponds, and
 10 acres surface area and 7 feet depth for recreational and fish ponds.

It should be noted that the depth of the water body is only necessary in the exposure equation if the application rate is given per volume (i.e., lb ai/ft[3] or lb ai/A-ft).

Future Research/Data Needs
Unavailable information that would refine handler exposure assessments for pesticide applications to aquatic areas include:

 Application intervals (i.e., how often chemicals are applied to aquatic sites)  -  either chemical-specific or generic information.
 Survey information (preferably longitudinal) detailing:
 Daily/weekly/monthly probability of treating aquatic sites with pesticides;
 Amount of product or formulation used or area treated per application;
 Product-specific application rates to obtain the likelihood that the maximum rate is used.
 Handler exposure data, specifically for aquatic site applications, and/or describing the extent to which an individual's exposure for a given formulation and application method varies from application-to-application.

Exposure Characterization and Data Quality

Unit Exposures
 The exposure data underlying unit exposures are considered reasonable for the purposes of estimating exposure.  The data are from actual applications using standardized exposure sampling methodologies and laboratory analyses.
 The underlying assumption of the use of exposure data as unit exposures  -  proportionality between the amount of active ingredient handled and exposure  -  is uncertain, though potentially conservative.  However, as a prediction mechanism, it is considered practical and useful for the purposes of handler exposure assessment in a regulatory context.  It provides a straightforward handler exposure calculation method and enables risk mitigation in the form of formulation comparison and decreased application rates.
 The extent to which an individual's exposure (expressed via unit exposures) varies day-to-day or application-to-application is unknown; therefore, the assumption that there is no variation when assessing longer-term exposure durations is considered conservative.

Amount of active ingredient handled
 Information on the amounts of active ingredient handled for residential aquatic site application equipment is largely unavailable.  The estimates used, however, are believed to result in health protective exposure estimates.
 The extent to which the amount an individual will handle per application varies from day-to-day or application-to-application is unknown; therefore, the assumption that there is no variation when assessing longer-term exposure durations is considered conservative.

6.0	Post-application Exposure Assessment

Post-application exposure can result from conducting activities in previously treated areas, such as swimming in lakes and ponds following pesticide applications by professional pesticide applicators or by homeowners themselves.  It is assumed that post-application exposure will occur as a result of swimming in larger aquatic areas that may be treated by commercial applicators and/or homeowners in areas such as lakes and recreational ponds.  It is not anticipated that post-application exposure would occur after homeowner applications to smaller aquatic areas such as ornamental backyard ponds or fountains.  Adults and children 3 < 6 years old are considered the index lifestages for this exposure scenario as it is assumed that younger children (i.e., < 3 years old) won't spend as much time swimming in lakes/ponds.  Older children (6 to <11 years old and 11 to <16 years old) may spend slightly more time swimming on average, but the differences in other inputs (e.g., body weight, body surface area, inhalation rates) offset the higher exposure time input.  The exposures estimated for children 3 to <6 years old are anticipated to be protective of older children engaging in similar activities.

The equations and inputs for estimating exposures from recreational swimming in treated aquatic areas are generally derived from the SWIMODEL, developed by EPA as a screening tool to conduct exposure assessments of pesticides found in swimming pools and spas, and EPA's Risk Assessment Guidance for Superfund  -  Part E, Supplemental Guidance for Dermal Risk Assessment ("RAGS-E").  However, some of the inputs and parameters have been updated to reflect use in bodies of water (e.g., lakes, ponds) as opposed to swimming pools.

This section addresses standard methods for estimating exposure and dose for three scenarios resulting from swimming in treated aquatic areas such as lakes and ponds:

 Section 5.2.1 - Inhalation exposure during recreational swimming (both adults and children 3 < 6 years old),
 Section 5.2.1 - Dermal exposure during recreational swimming (both adults and children 3 < 6 years old); and
 Section 5.2.1 - Ingestion of water during recreational swimming (both adults and children 3 < 6 years old).

It should be noted that there may be additional routes of exposure from swimming in treated waters, such as buccal/sublingual (absorbed through the mouth), orbital/nasal (absorbed through the eyes or nose), and aural (absorbed through the ear).  It is generally assumed that exposure through these routes will be less than exposure via the dermal, inhalation and oral routes.  Therefore, these additional routes are not recommended to be routinely assessed for recreational swimmers.

6.1	Post-application Inhalation Exposure Assessment

Post-application inhalation exposure during recreational swimming is dependent on three factors:  the volatility of the chemical, inhalation rate, and exposure time.  Considering the strengths and limitations of available data and behavioral characteristics of potentially exposed lifestages, post-application inhalation exposure is assessed for adults and children 3 < 6 years old.

Post-application Inhalation Exposure Algorithm
The algorithm to calculate daily exposure and dose is shown below.  Residential post-application exposure assessment must include calculation of exposure on the day of application.  Therefore, though an assessment can present exposures for any day "t" following the application, it must include "day 0" exposure.
E=  Vp* IR * ET
Where:

E	= exposure (mg/day);
Vp	= chemical-specific vapor concentration (mg/m3),
IR	= inhalation rate (m3/hr), and
ET	= exposure time (hrs/day).
 Vp= Cw* H,*1,000 Lm3

Where:

Vp	= chemical-specific vapor concentration (mg/m3),
Cw	= chemical concentration in water (mg/L), and
H'	= dimensionless Henry's Law constant (unitless).

H'= HLCR*T
Where:

H'	= dimensionless Henry's Law constant (unitless),
HLC	= Henry's law constant (atm-m[3]/mole),
R 	= gas constant (8.19E-5 atm-m[3]/mole-K), and
T	= ambient temperature in terms of Kelvin units (293K = 20[o]C).

Absorbed inhalation dose, normalized to body weight, is calculated as:

      D= E*AFBW

Where:

D	= dose (mg/kg-day);
E	= exposure (mg/day);
AF	= absorption factor (inhalation); and
BW	= body weight (kg).

Post-application inhalation exposure following recreational swimming in treated aquatic areas is generally considered short-term in duration.  Refinement of this dose estimate to reflect a more accurate short-term multi-day exposure profile can be accomplished by accounting for the various factors outlined in Section 5.0 (all) such as residue dissipation, product-specific re-treatment intervals, and activity patterns.  If longer-term assessments (i.e., intermediate-, long-term, or lifetime exposures) are deemed necessary, similar refinements to more accurately reflect the exposure profile are recommended.

Post-application Inhalation Exposure Algorithm Inputs and Assumptions
Recommended values for post-application inhalation exposure assessments are provided in 6.1.1 below.  Following this table, each scenario-specific input parameter is described in more detail.  This description includes a summary of i) key assumptions; ii) data sources used to derive recommended input values; and iii) discussion of limitations that should be addressed when characterizing exposure.

Aquatic Applications  -  Recommended Point Estimates for Post-Application Inhalation Exposure Factors.
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      Vp
Chemical-specific vapor concentration (mg/m[3])
Calculated based on chemical concentration in water and dimensionless Henry's law constant
                                      Cw
Chemical concentration in water (mg/L)
         Based on either (1) monitoring data or (2) label information
                                     H'
Dimensionless Henry's Law constant (unitless)
                                  Calculated
                                      HLC
Henry's Law constant (atm-m[3]/mole)
                               Chemical-specific
                                       R
Gas constant (atm-m[3]/mole-K)
                                   8.19E-5
                                       T
Ambient temperature in terms of Kelvin units (K)
                                      293
                                      IR
Inhalation rate (m[3]/hr)
Adult
                                     0.64

Children 3 to <6 years old
                                     0.42
                                      ET
Exposure Time (hrs per day)
Adult
                                     0.025

Children 3 to <6 years old
                                     0.076
                                      BW
Body weight (kg)
Adults
                                      80

Children 3 < 6 years old
                                      19

Chemical concentration in water (Cw)
The chemical concentration in water can be estimated based on (1) chemical-specific monitoring data or (2) the application rate provided on the product label.  If the application rate provided on the label is only given in lb active ingredient (ai) per area (rather than lb ai/volume), then an assumption of 4 feet depth (and uniform distribution) can be used to estimate the concentration in water.  The assumption of 4 feet depth is based on best professional judgement, and is not meant to correspond to the assumption of water depth used for the residential handler assessment (if used), since the post-application assessment is meant to represent exposure to large water bodies treated by professional applicators that would typically be used for swimming (e.g., lakes, ponds, etc) and not smaller water bodies assumed to be treated by homeowners (e.g., backyard ponds or fountains).  It is acknowledged that lakes and ponds may have depths greater than 4 feet, but by using the assumption of 4 feet and uniform distribution, the calculation of water concentration results in a more conservative estimate.

Inhalation Rate (IR)
See Section 2.2 for discussion of inhalation rates.  The recommended point estimates for use
in post-application inhalation exposure assessments are 0.64 m[3]/hr for adults and 0.42 m[3]/hr for children 3 < 6 years old.

Henry's Law Constant (HLC)
A chemical-specific value in units of atm-m[3]/mole.

Gas constant (R)
A constant value of 8.19 x 10[-5] atm-m[3]/mole-K.

Ambient temperature in units of Kelvin (T)
A constant value of 293 K.

Exposure Time (ET)
The exposure time for swimming in aquatic areas is based on information provided in the 2011 Exposure Factors Handbook (USEPA, 2011).  Data are provided on the number of minutes per month spent swimming in a freshwater swimming pool (Tables 16-40 and 16-42).  Using these data, monthly time-weighted averages were calculated and the recommended point estimates for use in post-application inhalation exposure assessments are 0.025 hour/day for adults and 0.076 hour/day for children 3 < 6 years old.

Future Research/Data Needs
Unavailable information that would refine post-application inhalation exposure assessments for pesticide applications to aquatic areas include:

 Application intervals (i.e., how often chemicals are applied to aquatic areas)  -  either chemical-specific or generic information.
 Survey information (preferably longitudinal) detailing:
 Daily/weekly/monthly probability of treating aquatic areas with pesticides;
 Product-specific application rates to obtain the likelihood that the maximum rate is used; and,
 Daily activity patterns specific to aquatic areas.
 Post-application exposure data, specifically for aquatic areas, and/or describing the extent to which an individual's exposure for a given activity varies.

Exposure Characterization and Data Quality
 The vapor concentration of the pesticide applied to aquatic areas is expected to be a highly conservative estimate since the applications are made outdoors and it is expected that the concentration of the chemical will be diluted in outdoor air.
 The equations used to estimate inhalation exposure are more appropriate for chemicals that are considered volatile and may overestimate concentration for certain pesticides.
 The exposure time for swimming in aquatic areas is based on the average time spent in a freshwater swimming pool and is used as a surrogate for swimming in lakes/ponds.

6.2	Post-application Dermal Exposure Assessment

Post-application dermal exposure resulting from recreational swimming in previously treated aquatic areas are based on the chemical properties of the active ingredient and exposure factors such as surface area and exposure time.  Considering the strengths and limitations of available data and behavioral characteristics of potentially exposed lifestages, post-application dermal exposure is assessed for adults and children 3 < 6 years old.

Post-application Dermal Exposure Algorithm
The algorithm to calculate daily exposure and dose is shown below. Residential post-application exposure assessment must include calculation of exposure on the day of application.  Therefore, though an assessment can present exposures for any day "t" following the application, it must include "day 0" exposure.

E= Cw* Kp*SA*ET*CF
Where:

E	= exposure (mg/day),
Cw	= chemical concentration in water (mg/L),
Kp	= permeability constant (see equation below),
SA	= surface area (cm2),
ET	= exposure time (hrs/day),
CF	= conversion factor (0.001 L/cm3)

Kp= 10-2.72+ 0.71*logKow- 0.0061*MW
Where:

Kp	= permeability constant (cm/hr),
Kow	= octanol water coefficient,
MW	= molecular weight (g/mol).

Absorbed dermal dose, normalized to body weight, is calculated as:
D= EBW
Where:

D	= dose (mg/kg-day);
E	= exposure (mg/day); and
BW	= body weight (kg).

Post-application dermal exposure following applications to aquatic areas is generally considered short-term in duration.  Refinement of this dose estimate to reflect a more accurate short-term multi-day exposure profile can be accomplished by accounting for the various factors outlined in Sections 5.0 (all) such as residue dissipation, product-specific re-treatment intervals, and activity patterns.  If longer-term assessments (i.e., intermediate-, long-term, or lifetime exposures) are deemed necessary, similar refinements to more accurately reflect the exposure profile are recommended.

Post-application Dermal Exposure Algorithm Inputs and Assumptions
Recommended values for post-application dermal exposure assessments are provided in Table below.  Following this table, each scenario-specific input parameter is described in more detail.  This description includes a summary of i) key assumptions; ii) data sources used to derive recommended input values; and iii) discussion of limitations that should be addressed when characterizing exposure.

Aquatic Applications  -  Recommended Point Estimates for Post-Application Dermal Exposure Factors.
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      Cw
Chemical concentration in water (mg/L)
         Based on either (1) monitoring data or (2) label information
                                      Kp
Permeability constant
                        Chemical-specific or calculated
                                      SA
Surface area (cm[2])
Adults
                                    19,500

Children 3 < 6 years old
                                     7,600
                                      ET
Exposure Time (hrs per day)
Adults
                                     0.025

Children 3 < 6 years old
                                     0.076
                                      BW
Body weight (kg)
Adults
                                      80

Children 3 < 6 years old
                                      19

Chemical concentration in water (Cw)
The chemical concentration is water can be estimated based on (1) chemical-specific monitoring data or (2) the application rate provided on the product label.  If the application rate provided on the label is only given in lb active ingredient (ai) per area (rather than lb ai/volume), then an assumption of 4 feet depth (and uniform distribution) can be used to estimate the concentration in water.  The assumption of 4 feet depth is based on best professional judgement, and is not meant to correspond to the assumption of water depth used for the residential handler assessment (if used), since the post-application assessment is meant to represent exposure to large water bodies treated by professional applicators that would typically be used for swimming (e.g., lakes, ponds, etc) and not smaller water bodies assumed to be treated by homeowners (e.g., backyard ponds or fountains).  It is acknowledged that lakes and ponds may have depths greater than 4 feet, but by using the assumption of 4 feet and uniform distribution, the calculation of water concentration results in a more conservative estimate.

Permeability constant (Kp)
The permeability constant (cm/hr) is chemical-specific and can be estimated based on an equation for organic chemicals provided by EPA's Dermal Exposure Assessment: Principles and Applications (U.S. EPA, 1992).  NOTE:  Since the permeability constant provides estimates of an internal dose from the dermal route of exposure, the oral toxicity endpoint rather than the dermal toxicity endpoint is used to assess the risks from the dermal swimming route.

Surface area (SA)
The body surface area exposed during recreational swimming is based on the 2011 Exposure Factors Handbook (USEPA, 2011) Tables 7-9 to 7-11.  These estimates of body surface area represent total body surface area, and are considered conservative considering adults and children are assumed to be wearing bathing suits while swimming.  The recommended point estimates for use in post-application dermal exposure assessments are 19,500 cm[2] for adults and 7,600 cm[2]for children 3 < 6 years old.

Exposure Time
The exposure time for swimming in aquatic areas is based on information provided in the 2011 Exposure Factors Handbook (USEPA, 2011).  Data are provided on the number of minutes per month spent swimming in a freshwater swimming pool (Tables 16-40 and 16-42).  Using these data, monthly time-weighted averages were calculated and the recommended point estimates for use in post-application inhalation exposure assessments are 0.025 hour/day for adults and 0.076 hour/day for children 3 < 6 years old.

Future Research/Data Needs
Unavailable information that would refine post-application dermal exposure assessments for pesticide applications to aquatic areas include:
 Application intervals (i.e., how often chemicals are applied to aquatic areas)  -  either chemical-specific or generic information.
 Survey information (preferably longitudinal) detailing:
 Daily/weekly/monthly probability of treating aquatic areas with pesticides;
 Product-specific application rates to obtain the likelihood that the maximum rate is used; and,
 Daily activity patterns specific to aquatic areas.
 Post-application exposure data, specifically for residential aquatic area activities, and/or describing the extent to which an individual's exposure for a given activity varies.

Exposure Characterization and Data Quality
 Dermal permeability values are estimated based on an equation recommended in the EPA Dermal Exposure Assessment: Principles and Applications (EPA, 1992), which provides non-steady state values based on the molecular weight and the log Kow partitioning coefficient (i.e., lipophilicity).
 The exposure time for swimming in aquatic areas is based on the average time spent in a freshwater swimming pool and is used as a surrogate for lakes/ponds.

6.3	Post-application Non-Dietary Ingestion Exposure Assessment

This SOP provides a standard method for estimating the dose for adults and children 3 < 6 years old from incidental ingestion of water from treated aquatic areas (e.g., lakes).   This scenario assumes that swimmers ingest water that enters their mouth during swimming or playing in the treated water.

Post-application Incidental Ingestion Exposure Algorithm
Exposure from incidental ingestion of treated water is calculated as follows:

E= Cw*IgR*ET
Where:

E	= exposure (mg/day),
Cw	= chemical concentration in water (mg/L),
IgR	= ingestion rate of water (L/hr),
ET 	= exposure time (hrs/day).

Dose, normalized to body weight, is calculated as:

D= EBW
Where:

D	= dose (mg/kg-day);
E	= exposure (mg/day);
BW	= body weight (kg).

Post-application incidental ingestion following aquatic applications is generally considered short-term in duration. Refinement of this dose estimate to reflect a more accurate short-term multi-day exposure profile can be accomplished by accounting for the various factors outlined in Sections 1.3.2 and 1.3.4, such as residue dissipation, product-specific re-treatment intervals, and activity patterns. If longer-term assessments (i.e., intermediate-, long-term, or lifetime exposures) are deemed necessary, similar refinements to more accurately reflect the exposure profile are recommended.

Post-application Incidental Ingestion Exposure Algorithm Inputs and Assumptions
Recommended values for post-application incidental ingestion exposure assessments are provided in Error! Reference source not found. below.  Following this table, each scenario-specific input parameter is described in more detail.  This description includes a summary of i) key assumptions; ii) data sources used to derive recommended input values; and iii) discussion of limitations that should be addressed when characterizing exposure.

Aquatic Applications  -  Recommended Point Estimates for Post-Application Incidental Ingestion Exposure Factors.
                              Algorithm Notation
                                Exposure Factor
                                    (units)
                               Point Estimate(s)
                                      Cw
Chemical concentration in water (mg/L)
         Based on either (1) monitoring data or (2) label information
                                      IgR
Ingestion rate (L/hr)
                                     0.05
                                      ET
Exposure Time
(hours per day)
Adults
                                     0.025

Children 3 < 6 years old
                                     0.076
                                      BW
Body weight
(kg)
Adults
                                      80

Children 3 < 6 years old
                                      19

Chemical concentration in water (Cw)
The chemical concentration is water can be estimated based on (1) chemical-specific monitoring data or (2) the application rate provided on the product label.  If the application rate provided on the label is only given in lb active ingredient (ai) per area (rather than lb ai/volume), then an assumption of 4 feet depth (and uniform distribution) can be used to estimate the concentration in water.

Ingestion rate of water (IgR)
Water ingestion rates are based on the Risk Assessment Guidance for Superfund (RAGS) Part A (http://www.epa.gov/oswer/riskassessment/ragsa/) which references a value from the Superfund Exposure Assessment Manual (USEPA, 1988).  The recommended point estimate for use in post-application incidental ingestion exposure assessments is 0.05 L/hr of swimming for adults and children 3 < 6 years old.

Exposure Time
The exposure time for swimming in aquatic areas is based on information provided in the 2011 Exposure Factors Handbook (USEPA, 2011).  Data are provided on the number of minutes per month spent swimming in a freshwater swimming pool (Tables 16-40 and 16-42).  Using these data, monthly time-weighted averages were calculated and the recommended point estimates for use in post-application inhalation exposure assessments are 0.025 hour/day for adults and 0.076 hour/day for children 3 < 6 years old.

Future Research/Data Needs
Unavailable information that would refine post-application ingestion exposure assessments for pesticide applications to aquatic areas include:

 Application intervals (i.e., how often chemicals are applied to aquatic areas)  -  either chemical-specific or generic information.
 Survey information (preferably longitudinal) detailing:
 Daily/weekly/monthly probability of treating aquatic areas with pesticides;
 Product-specific application rates to obtain the likelihood that the maximum rate is used; and,
 Daily activity patterns specific to aquatic areas.
 Post-application exposure data, specifically for residential aquatic area activities, and/or describing the extent to which an individual's exposure for a given activity varies.

Exposure Characterization and Data Quality
 The study on which the water ingestion rates are based is a pilot study which attempted to measure water ingested while swimming.  While it is one of the first attempts at collecting this type of information, the study has some limitations.  One limitation is that the number of participants is low.  The study population included 12 adults (4 males and 8 females) and 41 children under 18 years of age (20 males and 21 females).  Another limitation is that the swimmers were studied while swimming in pool water, and the study author noted that the swimming behavior of pool swimmers may be similar to freshwater swimmers, but may differ from salt water swimmers.
 The exposure time for swimming is based on the average time spent in a freshwater swimming pool, and is used as a surrogate for lakes/ponds.

Appendix B.  Summary of Label Directions concerning Aquatic Uses

Aquatic use directions for Diquat Dibromide
Total application volume per area  not to exceed equivalent of 40 lb/SA per year for all treatments
Volume required to not exceed 4 lbs ai per surface acre (SA) based upon spray solution concentration
Wait 14 days between treatments
Do not use for drinking for a period of 3 days if applied at 4 lb ai1/SA, 2 days if applied at 2  to 1.5 lb ai1/SA, 1 day if applied at 1 lb ai1/SA,  or  1 day for spot spray (< 1 lb ai1/SA) applications.
0 day water use restriction for fishing and swimming
 Do not allow livestock or domestic animals to consume treated water for 1 day following application
Do not use treated water for spray tank applications and irrigation to turf and landscape ornamentals for 3 days if applied at 4 lb ai1/SA, 2 days if applied at 2 lb ai1 or 1.5 lb ai1/SA, 1 day if applied at 1 lb ai1 /SA or 1 day for spot spray (< 1 lb ai1/SA) applications.
 Do not use treated water for spray tank applications and irrigation to food crops and production  ornamentals until 5 days after application
 Water use restrictions restriction codes 5 -9) do not apply if treated water is demonstrated to not contain more than the designated maximum contaminant level goal (MCLG) of 0.02 mg/l (ppm) of diquat dibromide (calculated as cation)
No applications are to be made in areas where commercial processing of fish, resulting in the production of fish protein concentrate or fish meal is practiced. To control submersed weeds, apply at rate of 1 - 4 lb ai1/SA (per 4 foot depth).
For application only to still waters (i.e. ponds, lakes, and drainage ditches) where there is minimal or no outflow to public water
Public Waters (ponds, lakes, reservoirs, marshes, bayous, drainage ditches, canals, streams, rivers, and other slow-moving or quiescent bodies of water). If applied to public waters, must be used by Corps or Engineers, or Federal/State Public Agencies, or Applicators (and/or Licensees) certified for aquatic pest control that are authorized by state or local government.
Do not apply within 1600 feet upstream or within 400 feet down steam of operating potable water intake sites. Do not apply within 1400, 700, or 350 feet of potable water intake for rates of 4, 2, or 1 lb ai1/SA respectively.
Do not use the treated water for animal consumption, spraying, irrigation, or domestic purposes for 14 days after treatment
For 24C registrations; Do not treat water where depth is 3 feet or less. Do not apply by air.
Do not combine with copper.
Do not use for Algae control. Do not use for water lettuce.
Do not apply under conditions involving possible drift to food, forage or other plantings that might be damaged or the crops thereof rendered unfit for sale, use or consumption.
For water depths of 2 feet or less including shorelines, do not exceed 1 gallon per surface acre.
Apply only by spray to surface of lake with boom sprayer
Not for sale or use in New York State without supplemental special local needs labeling
To make application within these restricted areas, the intake must turned off for the time period specified on the Federal label or until the treated area contains less than the designated maximum contaminant level (MCL) of 0.02 mg/L (ppm) of diquat dibromide calculated as the cation by an approved assay [example: PAM II Spectrometric Method]
Prior to using this product in a particular county, contact the local Extension Service Office or the U.S. Fish and Wildlife Service for procedures and precautions to protect the threatened or endangered species.

References

Pond Kits, Koi-Garden Pond Kits-Waterfall Kits. 2013.
(http://www.pondandgardenwholesalers.com/servlet/the-Pond-Kits--dsh-by-size/Categories).

Ornamental and Retention Ponds:  Bridging the Gap Between Functional and Beautiful.  2004.
(http://www.landandwater.com/features/vol49no2/vol49no2_1.html).

A Pond in Your Garden.  Garden World.  2011.
(http://www.gardenworld.co.uk/a-pond-in-your-garden/).

GreenShare Factsheets.  University of Rhode Island Landscape Horticulture Program.  Water Gardens.  2001.
(http://www.uri.edu/ce/factsheets/sheets/watergarden.html).

Backyard Conservation  -  Backyard Ponds.  United States Department of Agriculture, Natural Resources Conservation Service.
(http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/newsroom/features/?cid=nrcs143_023601).

Build Your Own Pond.  Popular Mechanics.  2006.
(http://www.popularmechanics.com/home/improvement/outdoor-projects/2770526).

Management of Recreational and Farm Ponds in Louisiana.  Louisiana State University Agricultural Center.  2003.
(http://www.wlf.louisiana.gov/sites/default/files/pdf/publication/32846-management-recreational-and-farm-ponds-louisiana/mgmt-of-farm-ponds.pdf).

Texas Farm Ponds:  Stocking, Assessment, and Management Recommendations.  Texas Agricultural Extension Service.  1996.
(http://theurbanrancher.tamu.edu/retiredsite/aquatic/farmpond.pdf).

Guidelines for Designing and Managing Florida Ponds for Recreation.  Florida Fish and Wildlife Conservation Commission.
(http://www.myfwc.com/conservation/you-conserve/recreation/pond-management/).

Pond Management: Construction.  Virginia Department of Game and Inland Fisheries.  2013.
(http://www.dgif.virginia.gov/fishing/pondmanagement/construction.asp).

U.S. Army Corp. of Engineers  -  Kurt Getsinger (Aquatic use)

U.S. EPA. (1988). Superfund Exposure Assessment Manual. U.S. Environmental Protection Agency, Washington, DC.  EPA/540/1-881001.


                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY                              Washington, DC  20460

									OFFICE OF 									AIR AND RADIATION

June 28, 2011

MEMORANDUM

SUBJECT:	Meeting between EPA and CD-Adapco

FROM:	Arvon Mitcham, Mechanical Engineer, and Sam Waltzer, Environmental Engineer.

TO:	Docket EPA-HQ-OAR-2010-0162

This memorandum documents the meeting held on June 27, 2011, between representatives from the USEPA and CD-Adapco.  This meeting was a discussion of computational fluid dynamics (CFD) test data and general simulation practices.

Attendees included:

Arvon Mitcham, USEPA Sam Waltzer, USEPA Gregg Gustafson, CD-Adapco Fred Ross, CD-Adapco Kevin Horrigan, CD-Adapco