[Federal Register: February 11, 2009 (Volume 74, Number 27)]
[Notices]
[Page 6866]
[DOCID:fr11fe09-33]

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DEPARTMENT OF ENERGY

Federal Energy Regulatory Commission

Combined Notice of Filings

February 5, 2009.
    Take notice that the Commission has received the following Natural
Gas Pipeline Rate and Refund Report filings:

    Docket Numbers: RP97-313-001.
    Applicants: Ozark Gas Transmission, LLC.
    Description: Ozark Gas Transmission, LLC submits three negotiated
rate agreements between Ozark and Southwestern Energy Services Company.
    Filed Date: 02/02/2009.
    Accession Number: 20090203-0216.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP03-36-041.
    Applicants: Dauphin Island Gathering Partners.
    Description: Dauphin Island Gathering Partners submits Forty Third
Revised Sheet 9 to FERC Gas Tariff, First Revised Volume 1.
    Filed Date: 02/02/2009.
    Accession Number: 20090203-0214.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP08-426-006.
    Applicants: El Paso Natural Gas Company.
    Description: El Paso Natural Gas Company submits Substitute
Original Sheet 28H et al. to FERC Gas Tariff, Second Revised Volume 1A
in compliance with the Commission's 1/1/09 order.
    Filed Date: 01/21/2009.
    Accession Number: 20090123-0378.
    Comment Date: 5 p.m. Eastern Time on Monday, February 9, 2009.

    Docket Numbers: RP00-426-041.
    Applicants: Texas Gas Transmission, LLC.
    Description: Texas Gas Transmission, LLC submits First Revised
Sheet 52 et al. to Third Revised Volume 1 & a Negotiated Rate
Agreement.
    Filed Date: 02/03/2009.
    Accession Number: 20090204-0046.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP08-436-003.
    Applicants: Stingray Pipeline Company, L.L.C.
    Description: Stingray Pipeline Company, LLC submits Sub. Twentieth
Revised Sheet 5 of its FERC Gas Tariff, First Revised Volume 1, to be
effective 1/1/09.
    Filed Date: 02/03/2009.
    Accession Number: 20090204-0047.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP09-332-000.
    Applicants: Enbridge Pipelines (Midla), L.L.C.
    Description: Enbridge Pipelines, LLC submits Third Revised Sheet
111 et al. to FERC Gas Tariff, Fifth Revised Volume 1, to be effective
3/1/09.
    Filed Date: 01/30/2009.
    Accession Number: 20090203-0104.
    Comment Date: 5 p.m. Eastern Time on Wednesday, February 11, 2009.

    Docket Numbers: RP09-337-000.
    Applicants: Eastern Shore Natural Gas Company.
    Description: Eastern Shore Natural Gas Company submits Second
Revised Sheet 92 et al. to FERC Gas Tariff, Second Revised Volume 1.
    Filed Date: 02/02/2009.
    Accession Number: 20090203-0215.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP09-338-000.
    Applicants: Portland Natural Gas Transmission System.
    Description: Portland Natural Gas Transmission System submits First
Revised Sheet 343 et al., to FERC Gas Tariff, Second Revised Volume 1.
    Filed Date: 01/30/2009.
    Accession Number: 20090203-0213.
    Comment Date: 5 p.m. Eastern Time on Wednesday, February 11, 2009.

    Docket Numbers: RP09-339-000.
    Applicants: Tennessee Gas Pipeline Company.
    Description: Tennessee Gas Pipeline Company submits Tenth Revised
Sheet 324 et al. to its FERC Gas Tariff, Fifth Revised Volume 1
effective 3/5/09.
    Filed Date: 02/03/2009.
    Accession Number: 20090204-0048.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP09-340-000.
    Applicants: Columbia Gas Transmission, LLC.
    Description: Columbia Gas Transmission, LLC submits Original Sheet
1 et al. to FERC Gas Tariff, Third Revised Volume 1, to be effective 3/
3/09
    Filed Date: 02/03/2009.
    Accession Number: 20090204-0052.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Docket Numbers: RP09-341-000.
    Applicants: Constellation Energy Commodities Group, Macquarie Cook
Energy.
    Description: Notice of Change of Ownership, Request for Temporary
Waiver, Request for Expedited Action, and Request for Shortened Notice
Period of Macquarie Cook Energy, LLC and Constellation Energy
Commodities Group, Inc.
    Filed Date: 02/04/2009.
    Accession Number: 20090204-5073.
    Comment Date: 5 p.m. Eastern Time on Tuesday, February 17, 2009.

    Any person desiring to intervene or to protest in any of the above
proceedings must file in accordance with Rules 211 and 214 of the
Commission's Rules of Practice and Procedure (18 CFR 385.211 and
385.214) on or before 5 p.m. Eastern time on the specified comment
date. It is not necessary to separately intervene again in a subdocket
related to a compliance filing if you have previously intervened in the
same docket. Protests will be considered by the Commission in
determining the appropriate action to be taken, but will not serve to
make protestants parties to the proceeding. Anyone filing a motion to
intervene or protest must serve a copy of that document on the
Applicant. In reference to filings initiating a new proceeding,
interventions or protests submitted on or before the comment deadline
need not be served on persons other than the Applicant.
    The Commission encourages electronic submission of protests and
interventions in lieu of paper, using the FERC Online links at http://
www.ferc.gov. To facilitate electronic service, persons with Internet
access who will eFile a document and/or be listed as a contact for an
intervenor must create and validate an eRegistration account using the
eRegistration link. Select the eFiling link to log on and submit the
intervention or protests.
    Persons unable to file electronically should submit an original and
14 copies of the intervention or protest to the Federal Energy
Regulatory Commission, 888 First St., NE., Washington, DC 20426.
    The filings in the above proceedings are accessible in the
Commission's eLibrary system by clicking on the appropriate link in the
above list. They are also available for review in the Commission's
Public Reference Room in Washington, DC. There is an eSubscription link
on the Web site that enables subscribers to receive e-mail notification
when a document is added to a subscribed docket(s). For assistance with
any FERC Online service, please e-mail<EMAIL_ADDRESS>or
call<PHONE_NUMBER> (toll free). For TTY, call<PHONE_NUMBER>.

Nathaniel J. Davis, Sr.,
Deputy Secretary.
 [FR Doc. E9-2859 Filed 2-10-09; 8:45 am]

BILLING CODE 6717-01-P


Section II. D. 7  Page 1 of 35 II. D. Appendices: Drinking Water Exposure 7. Ground Water Exposure Assessment Based on the February 2005 SAP, the Agency revised the groundwater modeling effort to incorporate recommendations regarding model scenario set up and evaluations against monitoring data. The major modeling change relates to the way groundwater concentrations are calculated. Previously, OPP proposed to use only unsaturated zone pore water concentrations, as this was a readily available output from the models. In this revision, OPP has made modifications to the model scenario set up in order to capture spatially averaged saturated zone concentrations. In this way, the models should deliver more reasonable estimates of concentrations that may be found in drinking water in rural private wells. This altered conceptualization, as well as other details of the scenarios, is described in the sections that follow.

Preliminary results of the model output are given, and where possible this output is compared to monitoring data.

A. Groundwater Scenario Model Overview Figure II. D. 7.1 depicts the conceptualization of the groundwater scenario which evolved from the advice of the February 2005 SAP. In this conceptualization, the pesticide is applied to the soil surface ( or plant canopy) and precipitation or irrigation drive pesticide through the soil profile and into a saturated zone. Transport processes are simulated with three models   PRZM, RZWQM, and LEACHP   with each model performing the simulation calculations differently ( FIFRA SAP, 2005). Particulars of the model setups used to perform these calculations are described below.

All models simulated a shallow unconfined aquifer with a water table at 3.5 m below the surface. Well screen length was assumed to be 1 m, starting at the water table and extending to 4.5 m. The well concentration was calculated as the average pore water concentration across the length of the screen. The models were set up to deliver the average pore water concentration in the ` saturated' soil profile from 3.5 to 4.5 m. This was accomplished by means depending upon the models' capabilities, as described later.

The well depth was chosen to ensure reasonable conservativeness in the assessment and acceptable runtimes in the models. Furthermore, as some preliminary simulations have shown, well depth does not have a critical influence in these proposed scenarios. This is because the predominant means of degradation occurs in the top 1 meter of the profile ( see below), and dispersion effects that would be influenced by depth are considerably damped by using the 1 m spatially averaged concentration for output.

The models consider that degradation rates change through the soil profile. In general it should be expected that faster degradation occurs in the top of the profile and Section II. D. 7  Page 2 of 35 decreases at lower depths. OPP used the pesticide aerobic soil metabolism rate for the top 25 cm, and a linearly declining rate with depth to 1 m, below which only abiotic processes were in effect. The pesticide may degrade in the upper reaches of the soil profile by both abiotic and biotic processes and in the lower reaches and aquifer by abiotic processes only ( Figure II. D. 7.2). This is consistent with the default arrangement in the RZWQM model and is roughly equivalent to configurations used by Health Canada and the European FOCUS group ( see section on FOCUS below). Also, temperature and soil water content ( as they affect degradation) can be accounted for in LEACHP and RZWQM, but this function does not currently appear to be operating correctly in PRZM.

For some pesticides, well setbacks ( Figure II. D. 7.1) are specified by state or federal regulations. For such cases, the additional travel time for a pesticide to reach a drinking water well and the degradation that occurs during that time is taken into consideration by a plug flow model, as described later.

II. D. 7. 1  Depiction of general groundwater scenario concept for estimating pesticide concentrations in drinking water.

Water Table Lateral Groundwater Movement 100 cm Set back distance 350 cm Biodegradation Zone 100 cm Abiotic Degradation Pesticide Application Area Potable Well Section II. D. 7  Page 3 of 35 II. D. 7. 2  Conceptual model illustrating pesticide degradation through the soil and vadose zone.

B. Implementation of the Models With the exception of LEACHP, the application of a fixed saturated zone is beyond the usual application of these models. Thus some background investigations were required for these models to be parameterized for the conceptual model. This section describes the unique manners in which each of these models was parameterized in order to fit this conceptualization.

1. PRZM Although PRZM was not originally developed to simulate saturated conditions, a review of the model's structure and coding showed that saturated conditions could be effectively simulated by redefining the field capacity parameter. Soil compartments in PRZM are maintained at " field capacity" unless losses occur by evapotranspiration. Below the zone of evapotranspiration ( which occurs at the bottom of the defined root zone), PRZM maintains water at field capacity. Thus, a saturated zone can be created in PRZM by setting the field capacity parameter ( called THEFC in PRZM) to equal the porosity. By doing this, a constant water table can be created ( Figure II. D. 7.3). Output concentrations are taken as the spatial average over the depth from the top of the saturated zone ( at 3.5 m below soil surface) to 1 meter below the water table. Depending on rainfall and evapotranspiration characteristics of the particular scenario, this spatial averaging effectively represents temporal averaging of from 6 months to greater than one year ( i. e., 1 meter of water infiltrating into the water table takes from 6 months for Florida citrus scenario to greater than a year for Washington potato scenario).

Irrigation, when required by a scenario, is handled according to recent OPP guidance on PRZM irrigation ( memo from D. Young and M. Corbin to the OPP Water Section II. D. 7  Page 4 of 35 Quality Tech Team, July 2005). This guidance suggests that PRZM has only two appropriate ways to handle irrigation   either above the canopy or beneath the canopy. Other forms of irrigation listed in the PRZM manual were deemed inappropriate due to hydrologic improbabilities. In addition, because the quantity of irrigation water is coupled to root zone depth in PRZM, rooting depths were set to irrigation depths rather than actual rooting depths. This is especially important for deep rooting orchard crops for which irrigation water is only applied to satisfy water demand in the upper most soil layers ( otherwise, if rooting depth were set to 2 meters as in citrus irrigation, water would be unrealistically applied to satisfy the entire 2 meter depth).

II. D. 7. 3  PRZM scenario to simulate a fixed water table. Note the two unique adjustments to PRZM groundwater scenarios: 1) " Field capacity" set to porosity to simulate a saturated zone, and 2) root depth set to irrigation depth to ensure proper irrigation.

Simulated well screen: Pore Water Concentration Averaged over 1 meter Depth to Water Table ( 3.5 m)

" Field Capacity" set to Porosity Unsaturated Saturated Well Outlet Represents Spatial Average of Saturated Zone Water Table Root Depth set to Irrigation Depth 2. RZWQM The current version of RZWQM, like PRZM, was not designed to handle a constant depth saturated zone ( although USDA is currently revising RZWQM to handle this condition). Therefore, OPP set up tile drains and head gates to mimic a near constant water table depth. This is shown in Figure II. D. 7.4. In developing the scenarios, the tile drain spacing, lateral conductivity, and drain diameter were adjusted so that a water table formed just above the head gate, thereby giving some flow out of the drain at all times. Concentrations out of the drain are calculated in RZWQM by taking the average concentration of the overlying saturated zone ( from tile drain to top of water table). This method of calculation is fortuitous in that this is the concentration that one would expect from a well screened from the water table to 1 meter below the water table. This is especially fortuitous because RZWQM does not offer any other simple means to calculate spatially averaged concentrations. We note that USDA ARS has not completely agreed with manipulation of RZWQM in this way, but they have not discounted it. The set up is Section II. D. 7  Page 5 of 35 currently being evaluated by USDA ARS, and it is likely that ARS will be able to modify RZWQM to handle a fixed water table condition.

Irrigation in RZWQM is handled much the same as in PRZM, in that root zone depth is the depth at which soil moisture depletion is considered. Root zone depth was set equal to the desired depth of irrigation, as it was in PRZM.

II. D. 7. 4  Formation of relatively constant water table in RZWQM using tile drains and head gate. Note that tile drains and head gates do not actually represent their physical usage, but rather are implemented as a means to control the lower boundary condition.

Depth to Water Table set by head gate ( 3.5 m) Unsaturated Saturated Water Table Tile Drain set 1m below head gate RZWQM uses the average concentration of water between tile drain and water table as the drain outlet concentration 3. LEACHP Unlike the other models, LEACHP allows for a constant water table depth as a part of its normal functioning. Thus no special manipulations were required in this regard.

LEACHP uses the Richard's equation to simulate water movement. Five options are available to estimate soil water retention ( water content vs. matric potential) and hydraulic conductivity ( water content vs. hydraulic conductivity). The method used is option 5 ( Rawls and Brakensiek, 1985) which is based upon US soils, and considers as independent variables particle size distribution ( percent sand, silt and clay), soil organic matter, and, soil bulk density.

The automatic irrigation option was used. A * name. sch file which requires the depth where the soil water sensor is located ( 100 mm), the threshold matric potential ( 100 kaP) which triggers irrigation, and the replenishment depth ( 100 cm) was created.

4. Well Setbacks Section II. D. 7  Page 6 of 35 In some cases, well setbacks are required by federal or state regulations. These setback requirements specify the nearest distance to a well that a pesticide can be applied. For such cases, the additional travel time to the well allows for additional degradation. Reductions in concentration are calculated in these assessments by a plug flow approximation as follows:

       = k v L C C exp 0 where C = concentration at well [ mass/ volume] C0= concentration at point of application [ mass/ volume] L = well setback distance [ length] v = lateral groundwater velocity [ length/ time] k = degradation rate in aquifer [ time 1]

The travel time of the groundwater used in these scenarios is much shorter than travel time would be if only the pumping induced gradient ( cone of depression) of a private drinking well was considered. OPP made conservative estimates regarding natural, topographically/ stratigraphically driven groundwater lateral velocities ( e. g., velocities determined by elevation head and hydraulic conductivity of the substrate). As an example, consider the travel time through a setback for unretarded chemicals without regard to additional head induced by well pumping, which can be estimated by v r t n =

where r = setback radius v = natural lateral groundwater velocity tn = travel time of unretarded solute due to natural gradient The travel time of an unretarded chemical when only pumping induced hydraulic gradient is considered is determined from ( see for example USEPA 1993):

Q L r t s w    2 =

where  = aquifer porosity Ls= screened length of well Q = flow rate tw = travel time of unretarded solute For setback estimations, OPP assumed a high lateral velocity of 0.15 m/ day, which is the typical high end velocity that Russell et al. ( 1987) reported in the Central Ridge of Florida. For a 50 ft setback, travel time is about 100 days due to the natural topographic gradient ( elevation head). To determine the well induced travel time ( caused by gradient changes due to well drawdown), OPP assumed that a typical family uses 101 gallons per day ( 0.28 m3/ day) ( American Water Works Association estimate), a 1 m screened well, and a porosity of 30%. For a 50 foot setback, the well induced travel time Section II. D. 7  Page 7 of 35 is 570 days; the natural gradient travel is 17% of the well induced travel time, which is well within any reasonable expectation of the error within such calculations. For 1000 foot setbacks, the natural gradient travel time is less than 1% of the well induced travel time. Thus OPP neglected the velocity effects caused by private rural wells because of their insignificance.

C. Standard Generic Scenarios OPP developed four groundwater scenarios for the Carbamate Cumulative assessment ( Florida citrus, Georgia peanuts, North Carolina cotton, and Washington potato), and applied a consistent set of rules to establish a protocol. This selection process primarily involved selection of the soil characteristics, selection of the weather, and selection of appropriate crop management practices.

The most appropriate soils for each crop were selected by consulting the USDA Soil Data Mart ( http:// soildatamart. nrcs. usda. gov/). In cases where crops were likely to be grown on multiple soils in a region, the most vulnerable of the likely soils were chosen, as characterized by the soils hydrologic group ( A, B, C, or D), hydraulic conductivity, and organic matter content. Soil properties were taken from the Soils Data Mart and transformed into appropriate input parameters for each of the models.

Weather inputs were selected to represent the weather in closest proximity to the scenario location. In the case of RZWQM, weather was generated from CLIGEN, which is an integral part of RZWQM. For PRZM and LEACHM, 30 years of historical data was used as obtained from the EPA Office of Research and Development ( http:// www. epa. gov/ ceampubl/ tools/ metdata/ index. htm).

Specific management practices that might affect pesticide transport were included in the models in those cases where the practices were likely to significantly affect pesticide transport. Significant practices that were included were the pesticide application method and the application of irrigation water. Variations in tillage practices were ignored in the development of these scenarios, as characterization and parameterization of such practices are difficult and would be speculative. Irrigation and pesticide application practices were developed for the models after consultation with agricultural extension agents, review of open literature, and pesticide label information.

For this carbamate cumulative assessment, the four scenarios developed by OPP ( described in section 1D of the main document   see above) were intended to represent high carbamate use in areas of high groundwater vulnerability, and are discussed below.

1. Florida Citrus Most citrus production occurs on Florida's Central Ridge. Polk County is typical of the Ridge and has the highest acreage ( 101,000 acres in year 2000) in citrus production in Florida ( Obreza and Collins 2002). Groundwater in this region is particularly Section II. D. 7  Page 8 of 35 vulnerable to pesticide contamination due to the high water table and sandy soils with low organic matter content. For these reasons, OPP chose the Polk County area as representative of a typical highly vulnerable Florida citrus area. Figure II. D. 7.5 shows the approximate vicinity of the Florida citrus scenario. Additionally, the choice of this location is benefited by the availability of several ground water studies ( e. g., Jones et al. 1987; Hornsby et al., 1990, FL DEP 2005, USGS 2005), which will allow some evaluation of the scenario modeling performance.

II. D. 7. 5 Location of FL citrus scenario. The circle indicates the approximate vicinity.

a. Soil Citrus grows in the Entisols on the Florida Ridge which are characteristically low in organic matter content and drain water quickly. Typical soil series used for citrus production in Polk County are Candler, Tavares, and Astatula ( Obreza and Collins, 2002). These soils are predominantly sand (> 97%) and have a low organic matter content ( 0.5 to 2 percent; US Soils data mart). In mature citrus groves, organic content is even lower ( 0.5 to 1 percent; Obreza and Collins, 2002). Some salient features of these soils are given in Table II. D. 7.1. These soils are all in the Hydrologic Group A, meaning there is negligible runoff.

Table II. D. 7.1. Soil Properties Candler Series Soil Series Horizon2 ( cm) Texture Sand1 Silt1 Clay1 Saturated Hydraulic Conductivity 1 in/ hr Organic matter1 (%) Field Capacity1 Moist Bulk Density2 Avail. Water Capacity ( in/ in) pH Section II. D. 7  Page 9 of 35 Table II. D. 7.1. Soil Properties Candler Series Soil Series Horizon2 ( cm) Texture Sand1 Silt1 Clay1 Saturated Hydraulic Conductivity 1 in/ hr Organic matter1 (%) Field Capacity1 Moist Bulk Density2 Avail. Water Capacity ( in/ in) pH Candler 0  80 Sand 97.5 1.25 1.25 6 50 0.5  1.0 0.025 0.058 1.35 1.55 0.04 0.08 4.5 6 Tavares 0 8 Sand 97 1.5 1.5 7 39 0.5 1.0 0.025 0.05 1.25 1.6 0.05 0.10 3.6 6 8 80 Sand 97 1.5 1.5 7 39 0 0.5  1.40 1.70 0.02 0.05 3.6 6 Astatula 0 7 Sand 98.5 0.75 0.75 9 85 0.5 1.0 0.025 0.05 1.25 1.55 0.04 0.10 4.5 6.5 7 80 Sand 98.5 0.75 0.75 9 85 0 0.5  1.45 1.60 0.02 0.05 4.5 6.5 1Obreza and Collins, 2002 2USDA Soils Data Mart b. Irrigation Central Ridge has relatively high rainfall (~ 50 inches/ year), but irrigation is necessary because of high drainage of the characteristic sandy soils on the Central Ridge. Because of the high sand fraction and the associated low water holding capacity, irrigation water management is difficult. As a result, microirrigation is commonly used, supplying only enough water to satisfy the tree demand ( Smajstra and Harman, 2002; Parsons and Morgan, 2004). Microirrigation typically supplies 10 20 gallons/ hour spread out over a 10 to 18 ft area, with durations of about 4 hours. Typically, microirrigation is set to satisfy water in the range of 1 to 2 feet below the surface, with irrigation events occurring about twice per week in the spring and up to 3 times per week in the summer ( communication L. Parsons, South Florida Agricultural Extension Office). During the spring, soil moisture depletion should be no less than 1/ 3 of the available water capacity ( AWC), while during the remainder of the year, up to 2/ 3 of the available water capacity can be depleted without severe effects ( Boman et al., 2002). Irrigation at 50% of AWC was assumed for modeling.

c. Citrus Production and Crop profile About one half of citrus in Florida is grown on deep ( Central Ridge), sandy soil using the unbedded tree row production technique. The remainder is grown on heavier and wetter soils in Florida Flatwoods. Citrus on the Central Ridge is planted along the natural contour. No leveling is required for the Entisols because of their natural drainage ( Obreza and Collins, 2002). Although Ridge citrus roots can penetrate as deep as 15 feet, most of the roots are in the top 3 feet. Because rooting depth is coupled to the depth of irrigation in all of the transport models, rooting depth in the models should be set to the appropriate depth of irrigation (~ 2 feet in the case of Ridge citrus).

d. Water Table and Aquifer Characteristics The water table in the region has an upper limit 3.5 to 6 feet below the surface ( USDA Soils Data Mart). The upper limits are generally reached in the winter months ( January to December). Typical depths may be considerably deeper. For example in the Section II. D. 7  Page 10 of 35 groundwater study conducted by Hornsby et al. ( 1990) in this area, water table depths were reported to be greater than 20 m. In the study of Jones et al ( 1987), depths of 4 m were reported.

Jones et al ( 1987) reported that a representative typical high lateral groundwater velocity in the Ridge area was 0.15 m/ day. They also observed that the pH of the groundwater was typically 4.5, with a range of 3.5 to 6, and temperature of 20 to 25 C. The USGS Lake Wales Ground Water Monitoring Study ( http:// fisc. er. usgs. gov/ Lake_ Wales_ Ridge/) reports surficial aquifer pHs in the range of 4 to 7 ( median 4.9).

2. GA Peanuts The southern part of Georgia is an area of prime farmland, suitable for field and row crops. Crops grown in this region include cotton, peanuts, beans, fruit, tobacco, potatoes, sweet potatoes, grain corn, and melons among others. Peanuts were chosen as the representative crop because Georgia has the highest peanut acreage in the U. S., and acreage within Georgia is primarily concentrated in the southwestern part of the state. This area, lying in the Southern Coastal Plain, has shallow groundwater that is susceptible to contamination ( Donohue, 2001) and is used for drinking water in some cases ( Crandall and Berndt, 1996). For these reasons, OPP chose the area in Figure II. D. 7.6 for scenario development. In addition, a prospective groundwater study was conducted in this area ( MRID 43099601) which allows some evaluations regarding the suitability of the scenario parameterization. Section II. D. 7  Page 11 of 35 II. D. 7. 6 Location of the southern Georgia scenario. The circle indicates the approximate vicinity.

a. Soil Based on soil data from Cook and Colquitt counties ( Soil Data Mart, USDA, 2005; Ma et al., 2000), at the center of the relevant region ( Figure II. D. 7.6), Tifton loamy sand is the dominant soil ( 23.9% of coverage in the region) and is also a prime farmland soil. Tifton is a very deep, well drained soil on uplands. The subsoil is loamy and extends to a depth greater than 5 feet. Plinthite occurs below a depth of 30 to 50 inches. Ironstone nodules are present throughout the soil. Permeability is moderate throughout the subsoil. Available water capacity is moderate. Some properties of this soil that are relevant for pesticide transport modeling are listed in Table II. D. 72. This soil falls into the Hydrologic Group B.

Table II. D. 7.2. Soil Properties of the Southern Georgia Scenario Horizon ( cm) Texture Saturated Hydraulic Conductivity ( µ m/ s) Organic matter (%) Moist Bulk Density Available Water Capacity ( in/ in) pH 0  25 Loamy sand 42  141 0.5  1.0 1.3  1.55 0.03   0.08 4.5  6.0 25 46 Fine sandy loam 42  141 0.5  1.0 1.45  1.65 0.08 0.12 4.5  6. 46 83 Gravely sandy clay loam 4  14 0.0  0.5 1.5  1.7 0.12 0.16 4.5  6.0 83 162 sandy clay 1.4  4 0.0  0.5 1.55  1.80 0.1. 13 4.5  5.5 162 216 sandy clay 1.4  4 0.0  0.5 1.65  1.85 0.1 0.12 4.5  5.5 b. Irrigation Section II. D. 7  Page 12 of 35 Georgia peanuts are grown on dryland and on irrigated land. About 50% of Georgia peanut acreage is irrigated. Typical irrigation amounts may be around 1 to 2 inch per week using center pivots. Total seasonal use could be 10 inches.

c. Crop Production and Profile Peanuts are typically rotated with cotton or a grass type crop. Conventional tillage is used for almost all Georgia peanut crops. Planting dates are from April 23 and May 25, and harvest runs from early September to early November. Plantings are typically single rows 36 inches apart.

d. Water Table and Aquifer Characteristics The water table is typically at a high of 4 to 6 feet below the ground surface, and some domestic wells draw from this shallow aquifer. The pH of the surficial aquifer in the Southern Coastal Plain ranges from 4.1 to 7.4 ( median 5.2) according to a survey by Crandall and Berndt ( 1996).

3. NC Cotton North Carolina is ranked sixth in the nation in cotton acreage and seventh in production, generating 5 percent of the United States cotton crop. Most of the cotton produced in North Carolina is grown in the eastern half of the state, or the coastal plain region. Three of the four highest cotton producing counties, Northampton ( 63045 acres), Halifax ( 61933 acres), and Edgecombe ( 46001 acres), in North Carolina are located in northeastern North Carolina ( USDA, Ag Census, 2002, http:// www. nass. usda. gov/ census/ census02/ volume1 / us/ us2appxa. pdf). Figure II. D. 7.7 shows the region for which this scenario was developed. Crops grown in this region include corn, peanuts, tobacco, soybeans, small grains, cotton, and pasture.

The coastal plain is North Carolina's largest physiographic province, covering 45 percent of the state. The province can be subdivided into two regions   outer and inner coastal plain. The outer coastal plain ( sometimes called the ' tidewater' region) consists of the immediate coast, barrier islands, sounds, marshes, lower river systems and associated mainland, and is generally less than 20 ft in elevation. The inner coastal plain includes the region from the outer coastal plain to the Fall Line.

The climate of North Carolina's coastal plain province is temperate. Average high temperature during summer months is in the mid upper 80s, while average lows are near 70 degrees. During winter, average highs are in the mid 50s, while average lows are in the mid 30s. Temperatures tend to be more moderate n the outer coastal plain. Average rainfall is about 51 inches. Snowfall is infrequent and generally averages less than 5 inches per year in the inner coastal plain and less than 2 inches per year in the outer coastal plain. Section II. D. 7  Page 13 of 35 II. D. 7. 7 Location of the North Carolina scenario. The circle indicates the approximate vicinity.

a. Soils Cotton is predominately grown on sandy loam soils of the coastal plain. These soils require subsoiling ( treatment to fracture and/ or shatter soil with narrow tools below the depth of normal tillage with a minimum mixing of the soil) to breakup naturally occurring hardpans. Dominant cotton soils in the three counties of interest ( Edgecombe, Halifax, Northampton) are the Norfolk loamy sand ( Fine loamy, kaolinitic, thermic Typic Kandiudults) and Wagram loamy sand ( Loamy, kaolinitic, thermic Arenic Kandiudults). The Norfolk loamy sand was selected as it is present in both Edgecombe and Northampton counties, is designated as prime farmland, and is an NRCS benchmark soil ( National Soil Handbook, part 630). This soil is Hydrologic Group B.

Table II. D. 7.3. Soil Properties Norfolk Series Horizon ( cm) USDA Texture Saturated Hydraulic Conductivity1 in/ hr Organic matter1 (%) Field Capacity2 ( 33 kPa) Wilting Point ( 1500 kPa) 2 Moist Bulk Density1 Available Water Capacity ( in/ in) pH 0  9 Loamy sand 42 141 0.5 2.0 5.1 2.0 1.55 1.7 0.06 0.11 3.5 6.0 9 14 Loamy Sand 42 141 0.3 0.8 5.1 2.0 1.55 1.7 0.06 0.11 3.5 6.0 14 70 Clay Loam 4 14 0 0.5 12 8 1.3 1.65 0.1 0.18 3.5 5.5 70 100 Clay loam 4 14 0 0.5 13 10 1.2 1.65 0.12 0.18 3.5 5.5 1USDA Soils Data Mart 2Approximated from USDA Norfolk pedons NSSL query c. Irrigation Limited cotton acreage in North Carolina is irrigated. The USDA Ag Census 2002 estimates that about 3.4% of acreage is irrigated. Irrigation is not included in the NC cotton model scenario. Section II. D. 7  Page 14 of 35 d. Cotton Production and Profile The majority of cotton is located on the sandy loam soils of the coastal plain; these require subsoiling to break naturally occurring hardpans. However, about 20 percent of the cotton produced in the coastal plain is grown on heavier soils that do not require subsoiling. No till systems are gaining in popularity in these locales, as the soils have higher levels of organic matter and are often the most productive. Traditionally, these soils have been heavily tilled, utilizing two disking operations followed by subsoiling/ bedding. Strip till is increasing dramatically in this area as a method of controlling sand blasting. The heavier clay soils of the piedmont do not require subsoiling, and most of this cotton is produced in no till systems.

Planting begins in mid April and usually is finished by the end of May ( most active is May 1 to May 29). Harvesting begins at the end of September and ends mid December ( most active is October 15 to November 15).

4. WA Potato A major crop for Washington is Irish Potatoes, grown primarily in the central portion of the state ( Figure II. D. 7.8). Washington is the second leading potato growing state in the U. S. ( WA Dept. of Ag, Statistics). The highest potatoproducing areas within the state are located in Grant and Yakima counties. These are also the counties with the highest usage of carbamates in the northwest. Grant County was the top potato producing county in the nation in 1998 ( WA Dept. of Ag, Statistics), with almost 50,000 acres in potato production in 2002 ( USDA, NASS 2002 Census of Agriculture). Groundwater is generally shallow in Grant County, with little or no overlying confining layer in most places. As is typical for areas where potato production is favorable, the soils tend to be coarse grained and well drained ( Sieczka and Thornton, 1993). Sandy, well drained soils are also likely to be fairly low in organic carbon; carbon ( and nutrient) loss is exacerbated by common potato production practices, such as heavy tillage ( Lang et al., 1999). These factors make Grant County especially susceptible to groundwater pesticide contamination. Figure II. D. 7.8, location of the hypothetical central Washington potato scenario. Section II. D. 7  Page 15 of 35 II. D. 7. 8  Washington State County Map. Grant County ( circled) and Yakima County are the major potato producing counties in the state.

a. Soil Potatoes are primarily grown in Entisols ( Torriorthents, Torripsamments) and Aridisols ( Haplocambids, Haplodurids) in central Washington, which are generally characterized by low clay content, good drainage, and low organic content ( USDA Keys to Soil Taxonomy, 2003). The most productive and widespread soil series cropped with potato in Grant County ( and other areas within the central Washington region) are Kennewick, Sagehill, and Wiehl ( USDA NRCS, Soil Data Mart). These soils tend to be coarse grained ( sand fractions typically range from 60 80%) with low organic matter content (< 1%). Most of these soils are in hydrologic group B. Several relevant soil properties are listed in Table II. D. 7.4. Section II. D. 7  Page 16 of 35 b. Irrigation Almost all potato crops grown in the Pacific Northwest ( and throughout the U. S.) are irrigated ( Thomson et al., 1999), largely because potatoes are grown in sandy, welldrained soils and because of crop water demand. Information included herein regarding crop yields, production techniques, etc. assume at least some irrigation is conducted. Therefore irrigation water must be included in total water inputs to the system ( e. g., precipitation plus irrigation water). Irrigation at 50% of AWC is used for this scenario.

c. Potato Production and Crop Profile Potatoes are among the most expensive major crops to grow. They require greater amounts of fertilizers ( especially N) and pesticides than grain and feed crops, and need more intensive management ( tillage, equipment, monitoring). Potato confers very little organic material to the soil. Although potatoes will grow on a wide variety of soils, optimal soils are usually deep, coarse grained, and well drained. Sandy soils are particularly good for potato production. Generally, soils with little or no slope are preferable, so that runoff is minimized ( and less water and organic matter is lost). Table II. D. 7.4. Washington Soil Properties for potato. Soil Series Depth ( in) Texture Sand (%) Silt (%) Clay (%) Saturated Hydraulic Conductivity ( µ m/ s) Organic Matter (%) Moist Bulk Density ( g/ cc) Available Water Capacity pH Kennewick 0 9 Loamy fine sand 61.5 79.9 16.6 35.0 3.5 4.0 14.0 0.5 1.0 1.15 1.45 0.11 0.17 7.4 8.4 9 60 Fine sandy loam   3.0 18.0 1.4 4.0 0 0.5 1.3 1.5 0.18 0.21 7.9 9.0 Sagehill 0 8 Very fine sandy loam 59.7 35.3 5.0 14.0 42.0 0 0.5 1.2 1.4 0.18 0.2 6.6 8.4 8 19 Silt loam   2.0 8.0 14.0 42.0 0 0.5 1.3 1.55 0.18 0.2 6.6 8.4 19 60 Fine sandy loam   2.0 8.0 4.0 14.0 0 0.5 1.3 1.6 0.18 0.2 7.9 9.0 Wiehl 0 8 Fine sandy loam 66.0 27.5 6.5 14.0 42.0 0.5 1.0 1.2 1.4 0.13 0.17 7.4 7.8 8 18 Silt loam   5.0 8.0 4.0 14.0 0 0.5 1.3 1.5 0.15 0.19 6.6 7.8 18 25 Gravelly silt loam   5.0 8.0 4.0 14.0 0 0.5 1.3 1.5 0.13 0.17 7.4 8.4 25 35 Weathered bedrock      1.6 1.9   Section II. D. 7  Page 17 of 35 Potato requires consistent amounts of water throughout its growing cycle. Seasonal requirements range from ~ 20 40 inches. It is advantageous to keep the soil near field capacity; soil should not be allowed to get below 65% of field capacity. However, soil should not be allowed to exceed field capacity, or quality and yield will become dramatically lowered. The effective rooting depth of potato is 2 feet ( Sieczka and Thornton, 1993).

d. Water Table and Aquifer Characteristics The water table associated with this type of soil in this region has an upper limit of 1 to 5 feet and a lower limit greater than 6 feet ( USDA Soil Data Mart). Groundwater pH for this region ranges from 6.7 7.8; typical pH for shallow ground water is generally around 7.2 ( personal communication, Washington State Dept. of Ecology).

D. Chemical Property Inputs Only two of the N methyl carbamates   aldicarb and oxamyl   were included in the groundwater assessment because the use data ( appendix IID. 2) and the relative toxicity suggest that these would be the major contributors to ground water exposure in the cumulative assessment. The chemical properties that drive these assessments are given in Table II. D. 7.5. These properties came from an evaluation of registrant submitted studies and represent reasonably conservative estimates of these properties. Other chemical properties are required as inputs in order for the models to operate, but they have negligible effect on model output; these properties can be found in the model input files. Properties for aldicarb represent total residue ( parent aldicarb, plus the degradates aldicarb sulfoxide and aldicarb sulfone) properties ( i. e. half lives represent the most stable toxic relevant constituent).

Table II. D. 7.5. Relevant Chemical Inputs for Carbamates. Koc Soil Metabolism halflife Hydrolysis ( acid) halflife Hydrolysis ( neutral) halflife Aldicarb ( total residue) 10 ml/ g 55 days 500 63 days oxamyl 6 ml/ g 20 days stable 8 days Section II. D. 7  Page 18 of 35 E. Results and Discussion 1. Florida Citrus a. Florida Citrus / Aldicarb Modeling results for the Florida citrus scenario are shown in Figure II. D. 7.9. The concentrations estimated by RZWQM are spikier than those of PRZM and LEACHP, but on average the concentrations are quite similar. Although peak concentrations are estimated to be higher in RZWQM than for PRZM, the overall average RZWQM concentration is 30% lower than PRZM. For the 1 lb/ acre application rate, the average concentration from PRZM is 27 ppb versus 19 ppb estimated by RZWQM. At the labeled rate of 5 lb/ acre and without any setback considerations, these values would be 135 and 95 ppb, respectively. Setbacks considerably reduce the concentrations. The 1000 ft set back reduces concentrations to about 4% of the application site concentrations, whereas the 300 ft setback reduces concentrations to about half of the site concentration. With a 1000 ft buffer concentrations are well below 10 ppb.

II. D. 7. 9  Florida Citrus Results for RZWQM, PRZM, and LEACHP. Application of aldicarb at 1 lb/ acre. For other application rates, the output concentrations are proportional. Distances in legend refer to setback distances as specified by state and federal regulations.

0 50 100 150 200 4/ 1/ 91 8/ 18/ 95 1/ 4/ 00 5/ 22/ 04 10/ 8/ 08 2/ 24/ 13 7/ 13/ 17 11/ 29/ 21 Date Aldicarb Residues ( ppb) No Buffer: RZWQM No Buffer: LEACHP No Buffer: PRZM 300 ft Buffer: RZWQM 300 ft Buffer: LEACHP 300 ft Buffer: PRZM 1000 ft buffer: RZWQM 1000 ft Buffer: LEACHP 1000 ft Buffer: PRZM Section II. D. 7  Page 19 of 35 b. Monitoring in Florida / Aldicarb These results are conservative with respect to a recent and on going groundwater monitoring study on the Florida Central Ridge ( http:// fisc. er. usgs. gov/ Lake_ Wales_ Ridge/). The USGS and the Florida Department of Agriculture is monitoring 31 wells within and around citrus groves on the Ridge ( the area of the OPP scenario). Well depths range from 4 feet to 110 feet deep ( two thirds in the 20 to 60 foot range), and pH ranged from 3.9 to 6.9 ( median about 5). Concentrations as high as 23 ppb have been recorded in one 26 ft well, while a 4 ft well had reported concentrations as high as 21 ppb. Summarized results are shown in FigureII. D. 7.10. This study is not targeted for any specific pesticide, but rather is designed as a survey mechanism   that is, it is not known how much aldicarb was used nor is it known how far aldicarb was used from the wells.

II. D. 7. 10  Monitoring results from the Lake Wales Central Ridge. Draft data subject to revision. Connected lines represent individual wells Aldicarb + Metabolites ( LWRMN)

0 5 10 15 20 25 April 1999 Oct/ Nov 1999 Apr/ May 2000 Oct 2000 Apr 2001 Oct 2001 Apr 2002 Oct 2002 Apr 2003 Oct 2003 Apr 2004 Oct 2004 Sample Date Aldicarb+ Ald. Sulfoxide+ Ald. Sulfone Concentration ( ug/ L)

In another monitoring study, Jones et al. ( 1987) applied 10 lb/ acre ( twice the current allowed label rate) to a grove plot on the Central Ridge and observed aldicarb residues in the saturated zone below the plot as high as 100 to 500 ppb. Concentrations of over 100 ppb were observed at distances of up to 300 feet from the point of application ( Fig 6 of Jones et al, 1987). With consideration that the Jones et al. ( 1987) application rate was twice as high as current labeled rates, our modeling scenarios would appear to be reasonably conservative for the types of soil / ground water profiles modeled. Section II. D. 7  Page 20 of 35 The Florida Department of Environmental Protection ( FDEP) monitors private drinking water wells in rural areas. The monitoring is not comprehensive, but instead is instituted when there has been an indication of a problem ( personal communication, FDEP). Total aldicarb residues ( parent, sulfoxide and sulfone degradates) as high as 47 ppb were reported in private drinking water wells in the early 1990s in the FDEP study. The concentrations dropped off in subsequent years. The reduction in concentrations of aldicarb may have resulted from label changes which reduced application rates and applied well setback requirements. Specific reductions at home sites also were also likely the result of a Florida State program to install carbon filters or to pipe water in from treatment facilities when contamination was found. Other reasons for the decline include the possibility of discontinued use in the vicinity of the contaminated areas ( personal communication FDEP).

Jones and Estes ( 1995) reviewed monitoring studies for aldicarb, including studies conducted on Florida Central Ridge citrus. They reported that 119 potable wells out of 4009 sampled wells in Florida had aldicarb residue detections and that 33 of those had concentrations higher than 10 ppb. A breakdown of the percent detections on the vulnerable Central Ridge was not made available, thus these values represent the entire state ( not specifically Ridge data).

c. Florida Citrus / Oxamyl Model results from oxamyl use on the Florida citrus scenario are given in Figure II. D. 7.11. Again, RZWQM predicts greater daily variations in concentrations and higher peak concentrations than does PRZM. Average concentrations are close, with PRZM giving 32 ppb and RZWQM giving 41 ppb, which is well within any reasonable expectation of certainty from these models. Oxamyl concentrations for this scenario are higher than for aldicarb, even though oxamyl has a shorter half life. This is because there are no setback requirements for oxamyl as there are for aldicarb.

Monitoring results are much more limited for oxamyl than for aldicarb. The USGS has just started to monitor for oxamyl on the Florida Ridge ( Choquette 2005, personal communication), and when these results become available, they will be evaluated with respect to model performance. Oxamyl was monitored for but not detected in the Florida Department of Health investigations ( study described above for aldicarb). Section II. D. 7  Page 21 of 35 II. D. 7. 11  Model Results for Oxamyl concentrations with Florida citrus scenario 0 20 40 60 80 100 120 140 160 180 0 2000 4000 6000 8000 10000 12000 days Oxamyl Concentration ( ppb) RZWQM PRZM 2. North Carolina Results for North Carolina are shown in Figure II. D. 7.12. Aldicarb is the only carbamate of interest in this area. The RZWQM simulation could not be performed with this scenario due to difficulties in establishing a water table. This problem is being worked out with assistance from USDA ARS. PRZM and LEACHP results were fairly close. OPP is searching for monitoring data for comparison with model results. Section II. D. 7  Page 22 of 35 II. D. 7. 12  PRZM and LEACHP output for Aldicarb Total Residue for NC cotton. Application rate is 1 lb/ acre.

0 5 10 15 20 25 30 35 40 45 50 5/ 1/ 1961 11/ 26/ 1967 6/ 22/ 1974 1/ 16/ 1981 8/ 13/ 1987 3/ 9/ 1994 date Aldicarb Residues ( ppb) PRZM LEACHP 3. Georgia Peanut Results for Georgia Peanuts are presented in Figure II. D. 7.13. Note that, as with all simulations here, concentrations are normalized to 1 lb/ acre; actual rates may be higher or lower, but output will be proportional to application rate. Because labels do not require buffers for Georgia Peanuts, no adjustments for buffers were included. Model simulations of groundwater concentrations in Georgia are typically lower than those in Florida ( without buffers). This is likely due to the lower rainfall and less irrigation used on peanuts, which causes pesticide to dwell longer in the upper 1 meter degradation zone. LEACHP concentrations are somewhat higher than PRZM or RZWQM calculations in this scenario. We are currently examining possible causes for this. OPP is searching for monitoring data for comparison with model results. Section II. D. 7  Page 23 of 35 II. D. 7. 13   PRZM, RZWQM, and LEACHP results for aldicarb for the Georgia peanut scenario. All concentrations are normalized to 1 lb/ acre.

0 10 20 30 40 50 60 70 80 0 2000 4000 6000 8000 10000 12000 days Total Aldicarb( ppb) PRZM RZWQM LEACHP 4. Washington Potato Both PRZM and RZWQM simulated negligible concentrations in the aquifer, consistent with an absence of detections from wells in this area ( Kirk Cook, Washington State Dept. of Agriculture, Pesticide Management Division, personal communication). This was primarily due to the alkaline pH of the system which enhanced hydrolysis. Further analysis was discontinued for his scenario.

F. European Approach to Ground Water: FOCUS Because EPA's proposed approach to addressing groundwater issues is new, a review of the approach that the European community uses is useful for placing the EPA's assessment into world perspective. The European community addresses standardization of evaluation of pesticide fate and transport through FOCUS ( FOrum for Co ordination of pesticide fate models and their Use; information available at http:// viso. ei. jrc. it/ focus/ index. html). A review of FOCUS and a comparison of EPA's results with those that would be derived from FOCUS methods are presented here. Section II. D. 7  Page 24 of 35 1. Background on European Regulatory Modeling The FOCUS groundwater scenarios are a set of nine standard combinations of weather, soil and cropping data which collectively represent agriculture in the European Union member countries for the purposes of a Tier 1 European Union Level assessment of leaching potential. The scenarios and their derivation are described in detail in a published report ( FOCUS, 1995). The scenarios have been implemented as sets of input files for four simulation models  MACRO, PEARL, PELMO & PRZM ( the reader should note that PRZM maintenance and improvement through FOCUS is done separately from PRZM as used by U. S. EPA regulators; at the present time there is not an exact match between versions of FOCUS PRZM and PRZM used by U. S. EPA).

The endpoints of concern evaluated in FOCUS modeling are driven by different legislative directives than in the United States. The use of pesticides that potentially contaminate the groundwater is banned by registration procedures at both the European level ( Council Directive 91/ 414/ EEC), and the level of individual member states ( countries). The Directive places great importance on the use of models to calculate Predicted Environmental Concentrations ( PECs) as a basis for assessing the environmental risks. Under the directive pesticide active ingredients and relevant metabolites thereof must not exceed a concentration of 0.1 ug/ l in groundwater.

In the first tier of the current procedure, point scale leaching models are combined with a limited number of worst case scenarios to assess PEC groundwater in Europe.

FOCUS model shells were used for running the models. The FOCUS shells guide the user to select input parameter values according to standardized procedures. The use of the standardized procedures means that some key input values may be different than was selected for the Carbamate Cumulative groundwater modeling of US scenarios. For example, the variance of pesticide half life with depth ( for this carbamate assessment) used the following standardized protocol for FOCUS modeling:

A " depth dependent correction factor" was applied to the pesticide degradation rates as follows: 0   30 cm depth 1 30   60 cm depth 0.5 60   100 cm depth 0.3 > 100 cm depth 0 Therefore, in the simulations run for total aldicarb residues, aldicarb degradation rate was reduced by half as aldicarb residues were passing through the 30 to 60 cm depth, by 70 % traveling between 60 and 100 cm deep, and no degradation took place for any residues that leached below 100 cm.

FOCUS models may use non linear adsorption of the pesticide. FOCUS PRZM differs from the PRZM version currently in use by EFED in this respect. Carbamate modeling used the FOCUS default assumptions and calculations as follows:

normalized Freundlich equation used; Section II. D. 7  Page 25 of 35

layer specific Kd calculated from the PRZM shell and inputted into PRZM;

Freundlich exponent 1/ n is entered in using the default value of 0.9 for n as specified in the FOCUS guidance document.

2. Interpretation of FOCUS Model Output based on Legislative Directives in the European Union The model shells rank the twenty mean annual concentrations ( in soil pore water moving past a depth of 1 meter) from lowest to highest. The seventeenth value ( fourth highest) is used to represent the 80th percentile value associated with weather for the specific simulation conditions. Under the FOCUS modeling system this value is taken as the overall 90th percentile concentration for a combination of soil and weather conditions since the standard scenario site soil characteristics have also been chosen to represent an overall 80th percentile vulnerability. In the European Union, evaluation of model output is made independent of the specific toxicological properties of the pesticide. 1 3. Comparison of FOCUS and Carbamate Cumulative Modeling Scenarios Four of the nine FOCUS scenarios were applicable to citrus production agriculture: Piancenza, Porto, Sevilla, and Thiva. With the possible exception of the Porto site, these sites represent drier climates ( Table II. D. 7.6) and less permeable soils ( Tables II. D. 7.7, 8, 9, and 10) than the scenarios used in the Carbamate Cumulative assessment other than the low natural rainfall but heavily irrigated Washington state potato scenario.

Table II. D. 7.6. European Union climate zones and predominance of agriculture represented by the FOCUS standard scenarios applicable to citrus uses.

Precipitation ( mm) Mean Annual Temperature ( ° C) Arable land * (%) Total Area * (%) Representative Locations 601 to 800 > 12.5 13 11 Sevilla/ Thiva**

1 Regulators in Europe compare the resultant chosen values for pesticide concentration in leachate against the 0.1 ug/ l standard for groundwater; with the three possible categories of outcomes being exceedences at none of the sites, at some of the sites, or at all of the sites. If residues do not exceed 01 ug/ l at any of the sites then the pesticide passes Tier 1 and may be registered because of its low probability of leaching to groundwater at concentrations in excess of 0.1 ug/ l. The FOCUS guidance document does offer the following caveat, however: " This does not exclude the possibility of leaching in highly vulnerable local situations within specific Member States, but such situations should not be widespread and can be assessed at the Member State level." When exceedences occur at some of the sites, then registration may only be approved in the regions represented by the scenarios where the pesticide concentrations were below 0.1 ug/ l. Registration may not be approved if the Tier 1 concentrations are above 0.1 ug/ l. The FOCUS guidance does provide, however, for the possibility that Tier 1 failures can be overruled by substantial contrary evidence ( that residues in groundwater will not in fact exceed 0.1 ug/ l under normal use patterns) obtained through " lysimeter or field leaching studies, monitoring and more refined modeling." Section II. D. 7  Page 26 of 35 801 to 1000 > 12.5 9 8 Piacenza < 600 > 12.5 4 4 Sevilla/ Thiva 1001 to 1400 > 12.5 3 3 Porto * Relative to the area of the European Union plus Norway and Switzerland. ** Although these locations have less than 600 mm of precipitation, irrigation typically used at these two locations brings the total amount of water to greater than 600 mm.

Table II. D. 7.7. Soil parameters for FOCUS Porto scenario.

depth classification pHH2O Texture µ m om oc bulk density depth factor@ cm < 2 2 50 > 50 % % g cm 3  0  35 loam 4.9 10 48 42 6.6 3.8 0.89 1.0 35  60 sandy loam 4.8 8 31 61 3.7 2.1 1.25 0.5 60  100 sandy loam 4.8 8 31 61 3.7 2.1 1.25 0.3 100  120 sandy loam 4.8 8 31 61 3.7 2.1 1.25 0.0 @ Factor applied to topsoil degradation rate.

Table II. D. 7.8. Soil parameters for FOCUS Piacenza scenario.

depth classification pH texture µ m om oc bulk density depth factor@ cm < 2 2 50 > 50 % % g cm 3 0 30 loam 7 15 45 40 1.72 1.00 1.3 1.0 30 40 loam 7 15 45 40 1.72 1.00 1.3 0.5 40 60 silt loam 6.3 7 53 40 0.64 0.37 1.35 0.5 60 80 silt loam 6.3 7 53 40 0.64 0.37 1.35 0.3 80 100 sand 6.4 0 0 100 0 0 1.45 0.3 100 170 sand 6.4 0 0 100 0 0 1.45 0.0 @ Factor applied to topsoil degradation rate.

Table II. D. 7.9. Soil parameters for FOCUS Sevilla scenario.

depth classification pH texture µ m om oc bulk density depth factor@ cm < 2 2 50 > 50 % % g cm 3  0 10 silt loam 7.3 14 51 35 1.6 0.93 1.21 1.0 10 30 silt loam 7.3 13 52 35 1.6 0.93 1.23 1.0 30 60 silt loam 7.8 15 51 34 1.2 0.70 1.25 0.5 60 100 clay loam 8.1 16 54 30 1.0 0.58 1.27 0.3 100 120 clay loam 8.1 16 54 30 1.0 0.58 1.27 0.0 120 180 clay loam 8.2 22 57 21 0.85 0.49 1.27 0.0 @ Factor applied to topsoil degradation rate.

Table II. D. 7.10. Soil parameters for FOCUS Thiva scenario.

depth classification pHKCl texture % om % oc bulk density depth factor < 2 2 50 > 50 % % g cm 3  Section II. D. 7  Page 27 of 35 0 30 loam 7.0 25.3 42.8 31.9 1.28 0.74 1.42 1.0 30 45 loam 7.0 25.3 42.8 31.9 1.28 0.74 1.42 0.5 45 60 clay loam 7.1 29.6 38.7 31.7 0.98 0.57 1.43 0.5 60 85 clay loam 7.1 31.9 35.7 32.3 0.53 0.31 1.48 0.3 85 100 clay loam 7.1 32.9 35.6 31.5 0.31 0.18 1.56 0.3 100??? clay loam 7.1 32.9 35.6 31.5 0.31 0.18 1.56 0.0 @ Factor applied to topsoil degradation rate.

4. Results of FOCUS Modeling for Aldicarb Total Residues The distribution of average annual concentrations of total aldicarb residues in leachate is provided in Figure II. D. 7.14. Tier 1 screening concentrations were 50 to 80 ug/ l for the four citrus production scenarios ( Table II. D. 7.11).

II. D. 7. 14  Distribution of annual average concentrations of total aldicarb concentrations at 1 meter depth after application of 1 lb ai/ A to citrus ( FOCUS European regulatory scenarios  PRZM simulations).

0 20 40 60 80 100 120 0% 20% 40% 60% 80% 100%

Exceedance Probability Annual Average at 1 m, ug/ L Piancenza Porto Sevilla Thiva There are major factors which tend to make the FOCUS screening concentrations either more or less " worst case" than the Carbamate Cumulative output:

FOCUS concentrations represent shallower water ( 1 m versus 3.5 m in the Carbamate Cumulative) and concentrations in leachate below the specified depth rather than concentrations in groundwater.

FOCUS concentrations represent annual mean rather than daily water concentrations Section II. D. 7  Page 28 of 35

The FOCUS scenarios were very likely less vulnerable than the Carbamate Cumulative scenarios in terms of soils and climate ( soils much less sandy; precipitation generally lighter).

In spite of the significant differences in the setup and evaluation of modeling, the FOCUS modeling yielded results within the range of Carbamate Cumulative modeling for aldicarb residues. This is important to know since the FOCUS models have already been through extensive use by regulators in Europe for several years now. Future work may be done with other FOCUS models such as PEARL and PELMO to confirm if similar results are obtained with the other FOCUS models.

Table II. D. 7.11. Selected Tier 1 concentrations for total aldicarb based on a 1 lb ai/ A application rate; EU citrus scenarios. Tier 1 values are calculated per the FOCUS guidance document.

European ( FOCUS) Site Name Tier 1 ground water concentration, ug/ l Piancenza 79.87 Porto 49.52 Sevilla 40.28 Thiva 50.06 G. Prospective Groundwater Monitoring ( PGW) Studies As part of the pesticide registration process, registrants are sometimes required to perform prospective ground water studies ( PGW) in order to better evaluate the fate and transport of a pesticide as it moves from a field site into the underlying ground water. A small number of studies have been performed on pesticides that are included in the list of n methyl carbamate cumulative chemicals. These include Oxamyl in North Carolina, Oxamyl in Maryland, and Methomyl in Georgia. The EPA is evaluating model performance with regard to these studies. The work is ongoing and preliminary results are presented in this section. As of this writing, only the analysis of the North Carolina oxamyl study has been completed to enough of an extent to present results.

1. North Carolina A small scale prospective groundwater monitoring study was conducted for oxamyl and its oxime metabolite in Tarboro, North Carolina. The study is located in the same coastal plain region modeled in the North Carolina cotton scenario. The study site was chosen for its highly vulnerable soil and hydrogeologic characteristics. The soil at the site is relatively homogeneous sand to loamy sand with a layer of sandy loam to sandy clay loam at approximately two to four feet. It correlates with the NRCS Tarboro loamy sand series, characterized by excessive drainage and negligible runoff. The top one foot of soil has an average organic matter content of 0.85% and a pH of 5.8. Below this, the organic matter content ranges from 0.10 to 0.23% while the pH ranges from 4.3 to 7.9, generally lower at the top and increasing with depth. Based on undisturbed soil samples, the average field capacity is 9.6% in the top two feet and 15.1% from two to four feet and the bulk density at those depths averages 1.42 g/ cm3. Section II. D. 7  Page 29 of 35 The study site has a history of cotton, soybeans, peanuts, tobacco, and corn production. For this investigation, cotton was planted on May 22, 1997 and multiple applications of oxamyl as well as a single application of a conservative bromide tracer were subsequently applied. The cotton was harvested in November and peanuts planted the following summer. Precipitation was supplemented with overhead center pivot irrigation to bring the combined precipitation and irrigation to 56.41 in., 120% of the historical mean precipitation ( Figure II. D. 7.15).

II. D. 7. 15  Precipitation and irrigation throughout the study period. The oxamyl application period is highlighted in light green..

0.0 0.5 1.0 1.5 2.0 2.5 3.0 6/ 1/ 97 10/ 1/ 97 1/ 31/ 98 6/ 2/ 98 10/ 2/ 98 Date Precipitation + Irrigation ( in)

Eight well clusters, including one shallow ( 12 17 feet screened interval) and one deep well ( 17 21 feet screened interval) each, were used to monitor groundwater and eight clusters of lysimeters at four depths were used to monitor soil pore water. During the study, the depth of the water table ranged from 10.27 to 17.15 feet, with a mean depth of 14.09 feet below the ground surface. Potassium bromide was applied as a conservative tracer on July 1, 1997, and indicated rapid vertical leaching and recharge to groundwater. It was detected in soil at all locations at the 18 to 24 inch depth by the first measurement at 27 days after treatment, and it reached groundwater in all shallow wells by 160 days after treatment.

In July, a series of 5 ground broadcast applications of oxamyl were made on a 2 acre plot at 6 to 8 day intervals. The first two applications were at a rate of 0.5 lb/ A and the rest at 1.0 lb/ A. This represents the maximum labeled seasonal rate using the minimum application intervals. Oxamyl reached all shallow wells, initially detected between days 124 and 194 after treatment. In one well, oxamyl persisted throughout the entire study period while in the others there were no detections beyond 376 days. The maximum detection was 3.91 ppb ( Figure Section II. D. 7  Page 30 of 35 II. D. 7.16). Oxamyl was only detected in 5 of the deeper wells, appearing by day 194 after treatment and undetected by day 378. The range of concentrations detected at this depth was 0.12 to 1.17 ppb ( Figure II. D. 7.16).

II. D. 7. 16   Oxamyl concentrations in shallow wells ( top) and deep wells ( bottom). Wells are grouped into subplots A, B, and C, where A is the most northern. Within each subplot, wells are listed upgradient to downgradient. Odd numbered shallow wells share a cluster.

Modeling work on this data has begun with an analysis of the bromide tracer in the shallow wells. The result PRZM and LEACHP are given in Figure II. D. 7.17 along with the bromide data ( RZWQM simulations have not been completed at the time of this writing). Both PRZM and LEACHP give similar responses, although LEACHP simulates a later arrival time than PRZM. Both predict higher concentrations than the data show. However note that lateral Section II. D. 7  Page 31 of 35 groundwater velocities at this location are quite high ( 51 feet per year) and that the groundwater flow transverses across the narrow side of the field. Thus advection and dispersion could have caused lower concentrations than those modeled In Figure II. D. 7.17, the highlighted data represent the wells that were farthest downgradient at the site, and as can be seen, these are the wells with the highest concentrations.

Preliminary work with the parent oxamyl has shown that the models predict substantially higher oxamyl concentrations than those shown in Figure II. D. 7.16. OPP is examining possible causes and will report results when available. Possibilities include an underestimation of the rate of degradation in the models. For example, under anaerobic conditions oxamyl half lives are on the order of 5 days, but this process was not included in the simulations. Investigations will continue and refinements may be necessary, but at the time of this writing modeling results have not compared well with the monitoring data.

II. D. 7. 17  Bromide concentration and model results of PRZM and RZWQM for the North Carolina study.

0 5 10 15 20 25 0 100 200 300 400 500 600 Days after application Conc. ( ppm) Bromide at 15 ft groundwater PRZM Simultaion LEACHP 2. Georgia A small scale prospective groundwater ( PGW) monitoring study was conducted in Cook County, Georgia from 1992 1993 to detect the presence of methomyl in ground water, soil pore water and soil. The study was located in the coastal plain region   the same region chosen for the Georgia peanut scenario ( see above). The site was selected for its hydrologic vulnerability: high annual rainfall; sandy, low organic matter, permeable soil profile; low slope; shallow groundwater; and extensive groundwater recharge. The soil profile was relatively homogenous with no restrictive layers and was characterized as Kershaw fine Section II. D. 7  Page 32 of 35 sandy loam, with texture characterized as sand. The mean concentrations of sand, silt and clay were 95%, 4%, and 2%, respectively. The mean organic matter content in the upper 0.5 feet of the profile was 0.9% and the mean soil pH at the plow layer was 6.4.

The study site had been under agronomic production for five years prior to the study and was planted with both sweet potatoes and peanuts. For this investigation, corn was planted on August 3, 1992 followed by multiple applications of methomyl and a single application of a conservative bromide tracer. Precipitation was supplemented via a traveling gun system to bring the combined precipitation and irrigation to 124% of the historical mean precipitation, based on the average of 30 years of meteorological data from two nearby weather stations.

Four two well clusters, one shallow and one deep, were installed to monitor groundwater and fourteen lysimeters were installed to monitor soil pore water at depths of 3 feet, 6 feet, 9 feet and 12 feet. During the study, the depth of the water table ranged from 7.71 to 22.42 feet, with a mean depth of approximately 15 feet below the ground surface. Potassium bromide was used as a tracer. Transport of bromide to a depth of 42 48 inches took between 22 and 34 days and was detected at elevated levels 62 DAT in one of the shallow wells ( MW07). Soil, soil pore water and groundwater samples were taken from three days prior to application of methomyl through 399 days after treatment.

Methomyl was first applied to postemergent corn on August 13, 1992. There were five whorl treatments spaced approximately 10 days apart and 20 daily ear treatments, conducted at 0.45 lbs ai/ acre each for a total of 11.25 lbs ai/ acre. The only detections of methomyl occurred at 62 and 117 days after treatment ( DAT). The maximum detection was 0.42 ppb in a shallow well at 62 DAT. Methomyl was detected in two of the deep wells at 62 DAT and in three of the shallow wells ( two at 62 DAT and two at 117 DAT). Only one shallow monitoring well, MW07 had detections above the detection limit at both 62 and 117 DAT.

The conductors of the study concluded that no detectable concentrations of methomyl were present in the groundwater and attributed the higher concentrations found at 62 and 117 DAT to be the result of either crosscontamination ( field or lab) or the presence of methomyl in the soil and/ or groundwater prior to the conduction of this study. These detections could also represent preferential flow delivery to the ground water. The presence of methomyl prior to the study was sampled for, and at the detection levels of 0.1 ppb for water and 2.0 ppb for soil, no methomyl was detected. In addition, there was no reported prior methomyl use at the study site.

Preliminary LEACHP modeling results, shown in Figure II. D. 7.18, indicate a plausible Br simulation. We are further investigating how well Section II. D. 7  Page 33 of 35 methomyl is simulated; no methomyl was detected in the PGW study, but model simulations revealed small but detectable concentrations. OPP will also evaluate similar simulations with PRZM and RZWQM using the same data set.

II. D. 7. 18  Bromide concentration and model results of LEACHP for the Georgia study.

0 80 160 240 320 400 480 560 640 720 800 0 8 16 24 32 40 Concentration ( mg/ L)

Days LeachP methomyl & leachP_ Br; PGW wells  BR_ MW1,3,5,7 METHOMYL LEACHP_ BR BR_ MW1 BR_ MW5 BR_ MW3 BR_ MW7 H. Outlook There is no clear " best" model to use to assess pesticide concentrations in groundwater. All three models give similar concentrations that are well within the uncertainty of any environmental prediction. Further evaluations will be required before OPP makes an ultimate decision on the groundwater model( s) to be used for general assessments. In this regard, OPP will continue its effort to evaluate the models on the performance and usability will continue as additional groundwater data is analyzed. OPP intends to analyze additional prospective groundwater studies, and is beginning to systematically enter relevant data into a database. Such an effort should allow model evaluation on a broader scale than just the available carbamate studies that were examined here.

OPP is continuing to work with USDA ARS, EPA ORD, and Health Canada in an effort to improve scenarios and models for pesticide groundwater assessments. Some of the issues currently being worked on include USDA ARS investigation into ways to implement a fixed water table in RZWQM, EPA effort to fix PRZM's temperature routines in PRZM, and Health Canada's efforts to develop consistent groundwater Section II. D. 7  Page 34 of 35 scenarios. These collaborative efforts should result in a consistent and reasonable process for estimating pesticide concentrations in groundwater.

I. References Boman, B., Morris, N. Wade, M. 2002. Water and Environmental Considerations for the Design and Development of Citrus Groves in Florida, Circular 1419, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL Choquette, A. F., and Sepulveda, A. A., 2000, Design of a shallow ground water network to monitor agricultural chemicals, Lake Wales Ridge, Central Florida: U. S. Geological Survey Water Resources Investigations Report 00 4134, 35 p.

Crandall C. A. and Berndt, M. P. 1996. Water Quality of Surficial Aquifers in the Georgia   Florida Coastal Plain, Water Resources Investigations Report 95 4269, U. S. Geological Survey, Tallahassee, FL.

Donohue, J. C. 2001. Ground Water Quality in Georgia for 2000 Georgia Department of Natural Resources , Environmental Prot4ection Division, Georgia Geologic Survey, Circular 12P, Atlanta, GA.

FOCUS. 2000. Leaching Models and EU Registration. European Commission Document 4952/ VI/ 95. Also available at: ftp:// ftp. ei. jrc. it/ pub/ FOCUS/ documentation/ FOCUS_ GW_ Report_ Main. pdf Hornsby, A. G., Rao, P. S. C., and Jones, R. L. 1990. Fate of Aldicarb in the Unsaturated Zone Beneath a Citrus Grove. Water Resources Research, 26( 10), 2287 2302.

Jones, R. L. and Estes T. L. 1995. Summary of Aldicarb Monitoring and Research Programs in the U. S. A. Journal of Contaminant Hydrology, 18, 107 140.

Jones, R. L. Hornsby, A. G., Rao, P. S. C. 1987. Movement and Degradation of Aldicarb Residues in the Saturated Zone Under Citrus Groves on the Florida Ridge. Journal of Contaminant Hydrology, 1( 3), 265 285.

Ma, Q., Hook, J. E., Wauchope, R. D., Dowler, C. C., Johnson, A. W., Davis, J. G., Gascho, G. J., Truman, C. C., Sumner, H. R., and Chandler, L. D. 2000. GLEAMS, OPUS, PRZM2  , and PRZM3 Simulations Compared with Measured Atrazine Runoff . Soil Sci. Soc. Am. J. 64: 2070 2079.

Noling, 2003. University of Florida IFAS Extension, ENY617, Institute of Food and Agricultural Sciences, University of Florida. ( also available at http:// edis. ifas. ufl. edu/ CH008) Section II. D. 7  Page 35 of 35 Obreza, T. A. and Collins, M. E. 2002. Common Soils Used for Citrus Production in Florida, BuSL 193. Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL ( also available at http:// edis. ifas. ufl. edu/ SS403)

Parson, L. R. and Morgan, K. T. 2004. Management of Microsprinkler Systems for Florida Citrus. HS 958, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL Rawls, W. J. and D. L. Brakensiek. 1985. Agricultural management effects on soil water retention. IN: DeCoursey, D. G. ( ed.). Proceedings of the 1983 Natural Resources Modeling Symposium. USDA. Department of Agriculture, Agricultural Research Service, ARS 30, p 532 p.

Smajstra, A. G. and Harman, D. Z. 2002. Irrigated Acreage in Florida: A Summary through 1998. CIR 1220 , Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL Smajstrla, A. G. B. J. Boman, D. Z. Haman, F. T. Izuno, D. J. Pitts and F. S. Zazueta 1997. BUL249. Basic Irrigation Scheduling in Florida. University of Florida IFAS Extension.

USDA, 2005. Soil Data Mart, Natural Resources Conservation Service, United States Department of Agriculture. http:// soildatamart. nrcs. usda. gov/.

USEPA, 1993. Wellhead Protection: A Guide for Communities, EPA/ 625/ R 93/ 002, U. S. Environmental Protection Agency, Washington, DC.

USDA, 2005. Soil Data Mart, Natural Resources Conservation Service, United States Department of Agriculture. http:// soildatamart. nrcs. usda. gov/.


[Federal Register Volume 88, Number 46 (Thursday, March 9, 2023)]
[Rules and Regulations]
[Pages 14495-14498]
[FR Doc No: 2023-04807]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2022-0101; FRL-10739-01-OCSPP]

Mandestrobin; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a tolerance for residues of
mandestrobin in or on Vegetable, tuberous and corm, except potato,
subgroup 1D. The Interregional Project Number 4 (IR-4) requested this
tolerance under the Federal Food, Drug, and Cosmetic Act (FFDCA).

DATES: This regulation is effective March 9, 2023. Objections and
requests for hearings must be received on or before May 8, 2023, and
must be filed in accordance with the instructions provided in 40 CFR
part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).

ADDRESSES: The docket for this action, identified by docket
identification (ID) number EPA-HQ-OPP-2022-0101, is available at
https://www.regulations.gov or at the Office of Pesticide Programs
Regulatory Public Docket (OPP Docket) in the Environmental Protection
Agency Docket Center (EPA/DC), West William Jefferson Clinton Bldg.,
Rm. 3334, 1301 Constitution Ave. NW, Washington, DC 20460-0001. The
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room and OPP Docket is<PHONE_NUMBER>. For the latest status
information on EPA/DC services, docket access, visit https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Daniel Rosenblatt, Acting Director,
Registration Division (7505T), Office of Pesticide Programs,
Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington,
DC 20460-0001; main telephone number:<PHONE_NUMBER>; email address:
[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this action apply to me?

    You may be potentially affected by this action if you are an
agricultural producer, food manufacturer, or pesticide manufacturer.
The following list of North American Industrial Classification System
(NAICS) codes is not intended to be exhaustive, but rather provides a
guide to help readers determine whether this document applies to them.
Potentially affected entities may include:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).

B. How can I get electronic access to other related information?

    You may access a frequently updated electronic version of EPA's
tolerance regulations at 40 CFR part 180 through the Office of the
Federal Register's e-CFR site at https://www.ecfr.gov/current/title-40.

C. How can I file an objection or hearing request?

    Under FFDCA section 408(g), 21 U.S.C. 346a, any person may file an
objection to any aspect of this regulation and may also request a
hearing on those objections. You must file your objection or request a
hearing on this regulation in accordance with the instructions provided
in 40 CFR part 178. To ensure proper receipt by EPA, you must identify
docket ID number EPA-HQ-OPP-2022-0101 in the subject line on the first
page of your submission. All objections and requests for a hearing must
be in writing and must be received by the Hearing Clerk on or before
May 8, 2023. Addresses for mail and hand delivery of objections and
hearing requests are provided in 40 CFR 178.25(b).
    In addition to filing an objection or hearing request with the
Hearing Clerk as described in 40 CFR part 178, please submit a copy of
the filing (excluding any Confidential Business Information (CBI)) for
inclusion in the public docket. Information not marked confidential
pursuant to 40 CFR part 2 may be disclosed publicly by EPA without
prior notice. Submit the non-CBI copy of your objection or hearing
request, identified by docket ID number EPA-HQ-OPP-2022-0101, by one of
the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov.
Follow the online instructions for submitting comments. Do not submit
electronically any information you consider to be CBI or other
information whose disclosure is restricted by statute.
     Mail: OPP Docket, Environmental Protection Agency Docket
Center (EPA/DC), (28221T), 1200 Pennsylvania Ave. NW, Washington, DC
20460-0001.
     Hand Delivery: To make special arrangements for hand
delivery or delivery of boxed information, please follow the
instructions at https://www.epa.gov/dockets/where-send-comments-epa-dockets.
    Additional instructions on commenting or visiting the docket, along
with more information about dockets generally, is available at https://www.epa.gov/dockets.

II. Summary of Petitioned-For Tolerance

    In the Federal Register of February 25, 2022 (87 FR 10760) (FRL-
9410-01-OCSPP), EPA issued a document pursuant to FFDCA section
408(d)(3), 21 U.S.C. 346a(d)(3), announcing the filing of a pesticide
petition (PP 1E8961) by IR-4, North Carolina State University, 1730
Varsity Drive, Venture IV, Suite 210, Raleigh, NC 27606. The petition
requested that 40 CFR 180.690 be amended by establishing tolerances for
residues of mandestrobin, 2-[(2,5-dimethylphenoxy)methyl]-[alpha]-
methoxy-N-methylbenzeneacetamide, in or on the raw agricultural
commodity: Vegetable, tuberous and corm, except potato, subgroup 1D at
0.01 parts per million (ppm). That document referenced a summary of the
petition prepared by IR-4, the petitioner, which is available in the
docket, EPA-HQ-OPP-2022-0101, https://www.regulations.gov. One comment
was received on the notice of filing. EPA's response to the comment is
discussed in Unit IV.C.

III. Aggregate Risk Assessment and Determination of Safety

    Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a
tolerance (the legal limit for a pesticide chemical residue in or on a
food) only if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) of FFDCA defines ``safe'' to mean that ``there is a
reasonable certainty that no harm will result from aggregate exposure
to the pesticide chemical residue, including all anticipated dietary
exposures and all other exposures for which there is reliable
information.'' This includes exposure through drinking water and in
residential settings but does not include occupational exposure.
Section 408(b)(2)(C) of FFDCA requires EPA to give special
consideration to exposure of infants and children to the pesticide
chemical residue in establishing a tolerance and to ``ensure that there
is a reasonable certainty that no harm will result to infants and
children from aggregate exposure to the pesticide chemical residue. . .
.''
    Consistent with FFDCA section 408(b)(2)(D), and the factors
specified in FFDCA section 408(b)(2)(D), EPA has reviewed the available
scientific data and other relevant information in support of this
action. EPA has sufficient data to assess the hazards of and to make a
determination on aggregate exposure for mandestrobin including exposure
resulting from the tolerances established by this action. EPA's
assessment of exposures and risks associated with mandestrobin follows.
    In an effort to streamline its publications in the Federal
Register, EPA is not reprinting sections that repeat what has been
previously published for tolerance rulemaking of the same pesticide
chemical. Where scientific information concerning a particular chemical
remains unchanged, the content of those sections would not vary between
tolerance rulemaking and republishing the same sections is unnecessary.
EPA considers referral back to those sections as sufficient to provide
an explanation of the information EPA considered in making its safety
determination for the new rulemaking.
    EPA has previously published a tolerance rulemaking for
mandestrobin in which EPA concluded, based on the available
information, that there is a reasonable certainty that no harm would
result from aggregate exposure to mandestrobin and established
tolerances for residues of that chemical. EPA is incorporating
previously published sections from this rulemaking as described further
in this rulemaking, as they remain unchanged.
    Toxicological profile. For a discussion of the Toxicological
Profile of mandestrobin, see Unit III.A. of the October 11, 2016, final
rulemaking (81 FR 70038) (FRL-9945-37).
    Toxicological points of departure/Levels of concern. For a summary
of the Toxicological Points of Departure/Levels of Concern for
mandestrobin used for human risk assessment, please reference Unit
III.B. of the October 11, 2016, final rulemaking.
    Exposure assessment. Much of the exposure assessment remains the
same although updates have occurred to accommodate the exposures from
the petitioned-for tolerance. These updates are discussed in this
section; for a description of the rest of the EPA approach to and
assumptions for the

exposure assessment, please reference Unit III.C. of the October 11,
2016, final rulemaking.
    EPA's dietary exposure assessments have been updated to include the
additional exposures from the new use of mandestrobin on the
commodities in vegetable, tuberous and corm, except potato, subgroup
1D. An unrefined chronic dietary (food and drinking water) exposure and
risk assessment was conducted using the Dietary Exposure Evaluation
Model software with the Food and Commodity Intake Database (DEEM-FCID)
Version 4.02. The chronic assessment used tolerance level residues for
all crops and assumed that 100% of the crops were treated with
mandestrobin. Empirical processing factors and the Agency's default
processing factors were used. An acute dietary exposure assessment was
not conducted since there was no adverse effect observed for a single
dose of mandestrobin.
    Dietary water exposure. The new use does not result in an increase
in the estimated residue levels in drinking water, so EPA used the same
estimated drinking water concentrations in the chronic dietary
assessments as identified in the October 11, 2016, rulemaking.
    Non-occupational exposure. There are no residential (non-
occupational) exposures expected from the proposed new use of
mandestrobin on vegetable, tuberous and corm, except potato, subgroup
1D. However, there are registered uses of mandestrobin on turf grasses
that cause non-occupational exposures. EPA's residential exposure
assessment has changed since the October 11, 2016, rulemaking. Because
all current mandestrobin labels require handlers to wear specific
clothing and personal protective equipment, EPA now assumes that
mandestrobin is applied by professional applicators, not residential
(homeowner) applicators. Therefore, the current assessment does not
consider exposure to residential handlers. For residential post-
application exposure, only hand-to-mouth exposures for children 1 to
less than 2 years old were assessed, as a dermal endpoint was not
selected.
    Cumulative exposure. Unlike other pesticides for which EPA has
followed a cumulative risk approach based on a common mechanism of
toxicity, EPA has not made a common mechanism of toxicity finding as to
mandestrobin and any other substances. For the purposes of this action,
therefore, EPA has not assumed that mandestrobin has a common mechanism
of toxicity with other substances.
    Safety factor for infants and children. EPA continues to conclude
that there are reliable data to support the reduction of the Food
Quality Protection Act (FQPA) safety factor (SF) from 10X to 1X for all
risk scenarios. See Unit III.D. of the October 11, 2016, final
rulemaking for a discussion of the Agency's rationale for that
determination.
    Aggregate risks and determination of safety. EPA determines whether
acute and chronic dietary pesticide exposures are safe by comparing
dietary exposure estimates to the acute population adjusted dose (aPAD)
and the chronic population adjusted dose (cPAD). Short-, intermediate-,
and chronic term aggregate risks are evaluated by comparing the
estimated total food, water, and residential exposure to the
appropriate points of departure to ensure that an adequate margin of
exposure (MOE) exists.
    An acute dietary exposure assessment was not conducted since there
was no adverse effect observed for a single dose of mandestrobin.
Chronic dietary risks are below the Agency's level of concern of 100%
of the cPAD; they are 2.7% of the cPAD for children 1 to 2 years old,
the most highly exposed population subgroup.
    The short-term aggregate exposure assessment for children 1 to less
than 2 years old includes dietary (food and drinking water) and
incidental oral exposure from hand-to-mouth activities from post-
application exposure to turf applications. The short-term aggregate
risk estimate for children 1 to less than 2 years old is an MOE of
2,900, which is greater than the level of concern of 100 and is not of
concern. An adult aggregate assessment was not conducted because there
are no existing/proposed residential handler scenarios. Since the
short- and intermediate-term points of departure (PODs) are the same
and short-term exposure estimates are greater than their intermediate-
term counterparts, the short-term aggregate risk assessment is
protective of the intermediate-term aggregate exposure. An acute
aggregate exposure assessment was not required due to no adverse effect
observed for a single dose for mandestrobin; and chronic aggregate
risks to adults and children are equivalent to the dietary (food and
drinking water) risks for those respective assessments and are not of
concern.
    Mandestrobin is classified as ``not likely to be a human
carcinogen'' based on the lack of treatment-related tumors in the
combined chronic/oncogenicity rat study or in the carcinogenicity mouse
study, and the lack of genotoxicity in an acceptable battery of
mutagenicity studies. As a result, EPA concludes that mandestrobin is
not likely to pose a cancer risk as a result of aggregate exposure to
the pesticide chemical residue.
    Therefore, based on the risk assessments and information described
above, EPA concludes there is a reasonable certainty that no harm will
result to the general population, or to infants and children, from
aggregate exposure to mandestrobin residues. More detailed information
on this action can be found in the document ``Mandestrobin. Human
Health Risk Assessment in support of Proposed Use on Vegetable,
Tuberous and Corm, except Potato, Subgroup 1D'' in docket ID EPA-HQ-
OPP-2022-0101.

IV. Other Considerations

A. Analytical Enforcement Methodology

    For a discussion of the available analytical enforcement method for
various crops, see Unit IV.A of the October 11, 2016, rulemaking.

B. International Residue Limits

    In making its tolerance decisions, EPA seeks to harmonize U.S.
tolerances with international standards whenever possible, consistent
with U.S. food safety standards and agricultural practices. EPA
considers the international maximum residue limits (MRLs) established
by the Codex Alimentarius Commission (Codex), as required by FFDCA
section 408(b)(4).
    The Codex has not established an MRL for mandestrobin in or on
Vegetable, tuberous and corm, except potato, subgroup 1D.

C. Response to Comments

    One comment was received in response to the Notice of Filing. The
comment stated in part that the Agency should deny this petition
because ``nobody is testing these toxic chemicals to see how they
affect big eaters over 100 years of life so that we know how they can
kil (sic) you.'' Although the Agency recognizes that some individuals
believe that pesticides should be banned on agricultural crops, the
existing legal framework provided by section 408 of the FFDCA
authorizes EPA to establish tolerances when it determines that the
tolerance is safe. Upon consideration of the validity, completeness,
and reliability of the available data as well as other factors the
FFDCA requires EPA to consider, EPA has determined that mandestrobin
tolerances are safe. The commenter has provided no information
indicating that a safety determination cannot be supported.

V. Conclusion

    Therefore, tolerances are established for residues of mandestrobin,
in or on Vegetable, tuberous and corm, except potato, subgroup 1D at
0.01 ppm.

VI. Statutory and Executive Order Reviews

    This action establishes tolerances under FFDCA section 408(d) in
response to a petition submitted to the Agency. The Office of
Management and Budget (OMB) has exempted these types of actions from
review under Executive Order 12866, entitled ``Regulatory Planning and
Review'' (58 FR 51735, October 4, 1993). Because this action has been
exempted from review under Executive Order 12866, this action is not
subject to Executive Order 13211, entitled ``Actions Concerning
Regulations That Significantly Affect Energy Supply, Distribution, or
Use'' (66 FR 28355, May 22, 2001) or Executive Order 13045, entitled
``Protection of Children from Environmental Health Risks and Safety
Risks'' (62 FR 19885, April 23, 1997). This action does not contain any
information collections subject to OMB approval under the Paperwork
Reduction Act (PRA) (44 U.S.C. 3501 et seq.), nor does it require any
special considerations under Executive Order 12898, entitled ``Federal
Actions to Address Environmental Justice in Minority Populations and
Low-Income Populations'' (59 FR 7629, February 16, 1994).
    Since tolerances and exemptions that are established on the basis
of a petition under FFDCA section 408(d), such as the tolerance in this
final rule, do not require the issuance of a proposed rule, the
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et
seq.), do not apply.
    This action directly regulates growers, food processors, food
handlers, and food retailers, not States or Tribes, nor does this
action alter the relationships or distribution of power and
responsibilities established by Congress in the preemption provisions
of FFDCA section 408(n)(4). As such, the Agency has determined that
this action will not have a substantial direct effect on States or
Tribal Governments, on the relationship between the National Government
and the States or Tribal Governments, or on the distribution of power
and responsibilities among the various levels of government or between
the Federal Government and Indian Tribes. Thus, the Agency has
determined that Executive Order 13132, entitled ``Federalism'' (64 FR
43255, August 10, 1999) and Executive Order 13175, entitled
``Consultation and Coordination with Indian Tribal Governments'' (65 FR
67249, November 9, 2000) do not apply to this action. In addition, this
action does not impose any enforceable duty or contain any unfunded
mandate as described under Title II of the Unfunded Mandates Reform Act
(UMRA) (2 U.S.C. 1501 et seq.).
    This action does not involve any technical standards that would
require Agency consideration of voluntary consensus standards pursuant
to section 12(d) of the National Technology Transfer and Advancement
Act (NTTAA) (15 U.S.C. 272 note).

VII. Congressional Review Act

    Pursuant to the Congressional Review Act (5 U.S.C. 801 et seq.),
EPA will submit a report containing this rule and other required
information to the U.S. Senate, the U.S. House of Representatives, and
the Comptroller General of the United States prior to publication of
the rule in the Federal Register. This action is not a ``major rule''
as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.

    Dated: March 3, 2023.
Daniel Rosenblatt,
Acting Director, Registration Division, Office of Pesticide Programs.

    Therefore, for the reasons stated in the preamble, EPA is amending
40 CFR chapter I as follows:

PART 180--TOLERANCES AND EXEMPTIONS FOR PESTICIDE CHEMICAL RESIDUES
IN FOOD

0
1. The authority citation for part 180 continues to read as follows:

    Authority: 21 U.S.C. 321(q), 346a and 371.

0
2. In Sec.  180.690, amend table 1 to paragraph (a) by adding in
alphabetical order an entry for ``Vegetable, tuberous and corm, except
potato, subgroup 1D'' to read as follows:

Sec.  180.690  Mandestrobin; tolerances for residues.

    (a) * * *

                        Table 1 to Paragraph (a)
------------------------------------------------------------------------
                     Commodity                        Parts per million
------------------------------------------------------------------------

                              * * * * * * *
Vegetable, tuberous and corm, except potato,                       0.01
 subgroup 1D.......................................
------------------------------------------------------------------------

* * * * *
[FR Doc. 2023-04807 Filed 3-8-23; 8:45 am]
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