Document ID: EPA-HQ-OPP-2012-0107-0010
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2013-05-15T04:00Z

OFFICE OF CHEMICAL SAFETY
AND POLLUTION PREVENTION
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460

MEMORANDUM

DATE:	July 19, 2012

SUBJECT:	Tier I Estimated Drinking Waters Concentrations (EDWCs) of Spirotetramat and its Transformation Products for the Use in the Human Health Risk Assessment for the Section 3 New Uses on Several New Crops
            (PC Code 392201; DP Barcode D398507)

FROM:	José L. Meléndez, Chemist
      Environmental Risk Branch V
      Environmental Fate and Effects Division

THROUGH:	Mah T. Shamim, Ph.D., Branch Chief
		Environmental Risk Branch V
		Environmental Fate and Effects Division (7507P)
		
TO:				Laura Nollen, Biologist
				Barbara Madden, Minor Use Officer
				Luis Suguiyama, Branch Chief
				Risk Integration, Minor Use and Emergency Response Branch
	Registration Division (7505P)

AND:			Julie VanAlstine, Environmental Health Scientist
				David Hrdy, Acting Branch Chief
				Registration Action Branch I				
		Health Effects Division (7509P)

      This memorandum presents the Environmental Fate and Effects Division's (EFED's) Tier I Estimated Drinking Water Concentrations (EDWCs) for spirotetramat (CAS No. 203313-25-1), and for two of its major transformation products spirotetramat-enol and spirotetramat-ketohydroxy, for use in the human health risk assessment by the Health Effects Division (HED).  The registrant has applied for several new uses for spirotetramat under Section 3 registration, including the following crops, crop groups or crop subgroups: bananas and plantains, bushberry and low growing berry subgroups (Crop Subgroups 13-07B and 13-07H, includes cranberries), various additional citrus fruits (to conform the Crop Group 10-10), coffee, pineapple, various additional pome fruits (to conform the Crop Group 11-10), pomegranate, bulb vegetables (Crop Subgroups 3-07A and 3-07B), various additional fruiting vegetables (to conform the Crop Group 8-10), globe artichoke, taro leaves (under the leafy vegetables group), and watercress (refer to the Appendix III).

      Using the Tier 1 aquatic models SCI-GROW v.2.3 (groundwater, for the use on bananas and plantains) and the Tier 1 Rice Model v.1.0 (surface water, surrogate model for the use on watercress), it was found that watercress at an application rate of 0.4 lb a.i./A/season (surface water) and bananas and plantains at 1.25 lb a.i./A/season (groundwater), were the uses involving the highest potential exposure.  The highest seasonal application rate is now different than from previous drinking waters assessments (DWAs); therefore, both the surface water and the groundwater EDWCs are different from the previous DWAs.  For the total toxic residues (spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy), the acute and chronic EDWC in surface water is 395 ppb and the EDWC in groundwater is 0.00124 ppb (Table 1-1).  These are dealt with in Appendix I for surface water and Appendix II for groundwater.  This DWA focuses on changes in EDWCs relative to previously reported values (refer to DP Barcode D345275, dated 01/22/2008; this is the DWA issued for the "new chemical," covering multiple crops).  Thus, this DWA relies heavily on the previous assessment in that the summary of the environmental fate properties and characterization, chemical structures, approaches, and several other details about spirotetramat were previously provided.

      Spirotetramat is a systemic broad spectrum tetramic acid insecticide (ketoenol class) that is applied as a preventative treatment during an early threshold of developing chewing insect population when sufficient leaf tissue is present for uptake and translocation to occur within agricultural crops.  The mode of action for spirotetramat is lipid biosynthesis inhibition (LBI); it belongs in the Group 23 Insecticides.  Residue exposure to surface water is typically possible through surface water runoff, soil erosion and/or off-target spray drift.  The mobility of spirotetramat is moderately high (Kd range 3.58-5.52 L/Kg, KOC range 184-437 L/KgOC, moderately mobile, FAO 2000).  Spirotetramat is labile, especially under aerobic soil metabolism conditions.  Nonetheless, its total residues are relatively persistent.  The Tier 1 EDWCs for spirotetramat and for its major transformation products spirotetramat-enol and spirotetramat-ketohydroxy (per HED's request; DP Barcodes D333437 & D345276, dated 05/14/2008), were calculated using the Tier 1 Rice Model v.1.0 (surface water, as a surrogate for applications to watercress) and SCI-GROW v.2.3 (groundwater, applications to bananas and plantains) for use in the human health risk assessment.  Table 1-1 provides a summary of the Tier I modeled drinking water concentrations.  This DWA presents screening level EDWCs for the use of spirotetramat.  A more definitive assessment and refinements are possible if needed by HED (see also notes below for further characterization of results).  Should any questions arise, contact EFED (melendez.jose@epa.gov).
      

Table 1-1.  Maximum Tier I Estimated Drinking Water Concentrations (EDWCs) for drinking water risk assessment based on ground or aerial application of spirotetramat on plantains and bananas (for groundwater) at 1.25 lb a.i./A/season, and ground, aerial or chemigation applications on watercress (for surface water) at 0.4 lb a.i./A/season.
Drinking Water Source (MODEL)

                Estimated Drinking Water Concentration  (EDWC)

Chemical:
                                    Parent
                                 Spirotetramat
                              Spirotetramat-enol
                           Spirotetramat-ketohydroxy
                         Total Toxic Residues (TTR)[1]

Risk \ Units
                                     (ppb)
                                     (ppb)
                                     (ppb)
                                     (ppb)
Ground-water (SCI-GROW)
Acute & Chronic [2]
                                 7.06 x 10[-5]
                                 5.15 x 10[-5]
                                 1.12 x 10[-3]
                                 1.24 x 10[-3]
Surface Water (Tier 1 Rice Model v.1.0)
Acute & Chronic [2]
                                      N/A
                                      N/A
                                      N/A
                                      395
 TTR = Total Toxic Residues (sum of spirotetramat + spirotetramat-enol + spirotetramat-ketohydroxy)
[2] Surface-water concentrations calculated by the Tier I Rice Model v1.0 and ground water concentrations calculated by SCI-GROW do not distinguish between peak and chronic concentrations.

Use Characterization

      Table III.A of Appendix III is a summary of all agricultural use patterns for spirotetramat in the labels for BYI 8330 150 OD Insecticide (oil dispersion), MOVENTO[(R)] SC (suspension concentrate), and the ULTOR[(R)] (suspension concentrate).  The uses shaded yellow are proposed new crops while the uses bold and underlined are the modeled ones.

	In comparing the crops in Table III.A against crops that were assessed in the 2010 DWA (DP Barcode D370675, dated 11/08/2010), it was noted that some previously assessed crops are not included in the labels available in Pesticide Product Label System (PPLS; at http://iaspub.epa.gov/apex/pesticides/f?p=PPLS:1).  These crops are cucurbit vegetables, cotton and various additional tropical fruits.  The Section 3 crops are at a range of application rates up to a seasonal rate of 1.25 lb a.i./A; foliar applications by ground, aerial, airblast, or chemigation methods (Table III.A).

Identification of specific data gaps

      The environmental fate database for spirotetramat is substantially complete.  At this time, no additional data has been required.

References

Food and Agriculture Organization of the United Nations.  FAO PESTICIDE DISPOSAL SERIES 8.  Assessing Soil Contamination: A Reference Manual.  Appendix 2. Parameters of pesticides that influence processes in the soil.  Editorial Group, FAO Information Division: Rome, 2000.    http://www.fao.org/DOCREP/003/X2570E/X2570E00.htm (accessed 07/17/2012).

U.S. Environmental Protection Agency 2007.  Guidance for Tier I Estimation of Aqueous Pesticide Concentrations in Rice Paddies (dated 05/08/2007). Available at http://www.epa.gov/oppefed1/models/water/rice_tier_i.htm (accessed 07/17/2012).
                                  Appendix I
       Surface Water EDWCs of Spirotetramat Total Residues on Watercress
      
   Watercress is typically grown in clean, flowing water, 2 to 3 inches deep.  The Agency does not currently have a methodology for exposure assessment for crops cultivated in flowing water, such as watercress. The Tier 1 Rice model v.1.0 was, therefore, used as the basis of the assessment of surface waters (refer also to Section 18 for the use on watercress in Florida, DP Barcode D399575, dated 04/05/2012), and the results were characterized to reflect differences between the capabilities of this model and the watercress cultivation practices.  Watercress is a very minor use (<700 acres were harvested in 2002 and 2007 across the U.S. and there were <65 farms, according to the U.S. Census of Agriculture, National Agricultural Statistics Service, U.S. Department of Agriculture).  Based on the previous review, and according to information provided by the registrant and IR-4, it appears that according to agricultural practices, watercress is grown in a bed of water which drains to a ditch which is constantly recirculated.  (In Florida, as per the Florida Department of Agriculture and Consumer Services Section 18 request, field plots are 4-acres sized each and laser leveled.)  The circulation of water is stopped 24 hours before and is turned on 24 hours after chemical applications.
   
   EFED is concerned primarily about the total toxic residues (TTR), as opposed to individual metabolites (spirotetramat, spirotetramat-enol and spirotetramat-ketohydroxy), from discharge towards adjacent bodies of water likely to occur at the end of the season.  EFED does not have a standard model for applications on watercress.  In order to represent the proposed use on watercress, the Tier 1 Rice model v.1.0 was provisionally used (USEPA 2007).  Individual metabolites were not modeled because this would double count mass of pesticide and transformation products in this particular model.  The simplified equation for the Tier 1 Rice Model v.1.0 is as follows:
   
   Cw= mai    '0.00105+0.00013Kd  

      Where:
      Cw = EDWC = water concentration [ug/L or ppb]
      mai' = mass applied per unit area [kg/ha] (i.e., the seasonal application rate)
      Kd = water-sediment partitioning coefficient [L/kg]

       For the applications of spirotetramat on watercress, the EDWC expression is based on spirotetramat-ketohydroxy, which is the last and persistent metabolite of the degradation pathway:

         Spirotetramat  Spirotetramat-enol  Spirotetramat-ketohydroxy

For spirotetramat, the calculation is therefore:

EDWC= 0.448320.00105+0.00013(0.6532) μg/L=395 μg/L

       Where the input parameters selected for the model and their justification and sources are specified in Table I.A.

Table I.A. Tier I Rice Model v1.0 input parameters for spirotetramat use on watercress
                                Input Parameter
                                     Value
                                 Justification
                                     Source
 Application Rate (mai')
                                    0.44832
 0.20 lb a.i./A/application x 2 applications = 0.4 lb a.i./A (x 1.1208 Kg·A/ha·lb) = 0.44832 kg a.i./ha
 Proposed spirotetramat labels (see Table 9)
 Soil-to-Water Partition Coefficient (Kd)
                                     0.6532
 Kd = Mean KOC[1] (65.32 L/Kgoc) x 1% organic carbon content = 0.6532 L/kg for the total spirotetramat residues
OECD Monograph Annex B. Spirotetramat. B.8 Fate and Behaviour
1. The representative partition coefficient used is the one for spirotetramat-ketohydroxy, which is the last metabolite in the degradation sequence and for which the KOC model is more suitable than the Kd model (i.e., the coefficient of variation is smaller).

A. Assumptions of the Tier 1 Rice Model v.1.0 (Provisional for Watercress Use)

   Most of the assumptions used in the Tier 1 Rice Model v.1.0 model help ensure that the outputs are protective of most environments associated with rice agriculture (noted though, that it is provisionally being used to represent the uses on watercress).  Rice cultivation differs from watercress in that for the latter the water is constantly flowing while for rice, the field is flooded.  The model assumptions include the following (see USEPA 2007 for parameterization information and further details):
   
   1. Movement of pesticide on suspended sediment is not considered (while for this use, water is constantly circulated except when pesticides are applied; the water circulation may promote pesticide movement).
   2. Degradation does not occur (notwithstanding, the TTR are relatively persistent to aerobic aquatic metabolism and moderately persistent to aerobic soil metabolism).
   3. Volatilization and other dissipation processes are not considered (for spirotetramat, the vapor pressure and Henry's Law Constant are low, indicating a low potential for volatilization, but other dissipation processes like degradation and metabolism are not considered).
   4. The partitioning to sediment is instantaneous.
   5. Water is available for human exposure instantaneously (because the chemical is likely circulated, it appears that the water would be discharged into adjacent bodies of water and would be of concern primarily at the end of the season).
   6. Water column depth is 10 cm.  (Based upon unofficial data, it appears that actual depth is in the range of 1 to 3 inches or around 2.5 to ~8 cm).  As per the registrant, chemical applications occur 24 hours after water circulation is stopped and water circulation is restarted 24 hours after application.)
   7. Sediment depth is 1 cm.
   8. All pore space is saturated with water.
   9. Organic carbon fraction is 0.01 (i.e., 1% OC).
   10. Bulk density is 1300 kg/m[3].
   11. Grain density is 2650 kg/m[3].

   The aerobic soil half-life for the TTR is on the order of 203.7 days and their partitioning is not too strong with a KOC of 65.32 L/KgOC (mobile according to FAO 2000, using the ketohydroxy as the representative chemical).  The aerobic soil metabolism half-life for spirotetramat-ketohydroxy, the last degradate in the degradation pathway is 12.38 days, and the rate determining step.  It is noted that neither the degradation of the pesticide nor the mass transfer from the aqueous phase to the sediment are considered in this conceptualization, which greatly simplifies the model.  The absence of degradation adds conservatism to the model (i.e., estimated concentrations should be higher than those usually found in rice paddies, considered representative of use on watercress).  The absence of mass transfer processes can either add or reduce conservatism depending on numerous conditions such as whether the pesticide is soil or water applied and whether actual degradation occurs preferentially in the sediment or the water compartment (refer to uncertainties below); however, consideration of this parameter is a refinement beyond a Tier 1 conceptualization.  Spirotetramat is actually foliarly applied and the chemicals (spirotetramat, spirotetramat-enol and spirotetramat-ketohydroxy) do not readily bind to bottom sediment.

B. Uncertainties of the Tier 1 Rice Model v.1.0 (Provisionally used for Watercress)
   
   The Tier 1 Rice Model v.1.0 provides screening-level estimates and as such, are expected to exceed peak values found in the environment in most cases.  They represent paddy discharge water that has not degraded, and has not diluted with uncontaminated water outside the paddy.  The aerobic aquatic metabolism is ~204 days for the TTR and the overall anaerobic aquatic metabolism, hydrolysis and aqueous photolysis processes are considered relatively persistent.  It is noted that the aqueous photolysis of the parent spirotetramat is 14.4 Phoenix, AZ days.  In sterile water, the only species observed is spirotetramat (i.e., the enol and ketohydroxy are not observed), while in natural water, spirotetramat-enol is observed peaking at 3 days and declining to <20% AR after 10 days and the ketohydroxy is not observed.
   
   The model does not account for crop interception which appears to be a very important component for this particular chemical.  Furthermore, it does not account for dilution occurring in the receiving body of water.  Direct discharge water is generally not expected to be used as a drinking water source.

      It was noted that the EDWCs obtained by the Tier 1 Rice Model v.1.0 were substantially higher than the acute EDWC for the TTR obtained in the previous assessment; therefore, various parameters were explored in order to assess the impact of certain variables and characterize the reported results.
      
      For DWA, evaluation of the Tier I Rice Model v.1.0 indicated that modeled within-paddy estimates are conservative, exceeding peak measured concentrations of pesticides in water bodies well downstream of rice paddies in five evaluated studies by less than one order of magnitude to multiple orders of magnitude.  The five studies assessed were conducted in Louisiana and California using four different pesticides (USEPA 2007).  It appears that the range of modeled estimate exceedances over measured concentrations is most likely in response to chemical, environmental, and study-specific factors.  Estimates from the Tier I model generally do not represent typical concentrations found in human drinking water, as they represent direct paddy discharge water.

      1. Crop Interception

      According to the labels (e.g., MOVENTO[(R)] SC) spirotetramat must be applied (tank mixed) with a spray adjuvant or additive having spreading and penetrating properties to maximize leaf uptake and systemicity of the active ingredient within treated plants.  The Section 3 label further says that "Sufficient leaf tissue must be present for uptake and translocation of this product..."  Later it says that, "Following application to plant foliage, MOVENTO is fully systemic, moving through phloem and xylem to new shoot, leaf and root tissues..."  This chemical is primarily active against immature insect life stages (i.e., aphids) that ingest plant tissue, and fertility of adult female insects may be reduced.  Spirotetramat has limited contact activity; it is a systemic lipid biosynthesis inhibitor, is ambimobile (i.e., it moves up and down through the plant tissue), and must be taken up by foliage in order to be effective against sucking insects.
      
      Therefore, under actual conditions of watercress cultivation, most of the applied pesticide should be taken up by the treated foliage (i.e., leaf tissue) of the watercress to be effective against aphids.  The fraction remaining on the leaves (expressed as a percentage), is referred to here as the crop interception (or efficiency of application).  A crop interception of 100% is the goal (i.e., that is, as much as possible of the chemical is intercepted by the foliage and not lost in the soil).  There is a fraction on the leaves that will also degrade (referred to as foliar decay), and a portion of it may be washed off of the leaves by rainfall or irrigation into the stream water below the foliage.  The impact of crop interception on the initial concentration in the rice paddy water is potentially significant.  If the crop interception is, for example 80%, the acute concentration could be reduced potentially by 80%.

      2. Pesticide Degradation
      
      Under field conditions, the aerobic soil metabolism is likely to be the main dissipation process when the pesticide is applied.  The reason is that spirotetramat is applied on dried field via foliar ground, aerial or chemigation methods.  The aerobic soil metabolism half-lives for spirotetramat and for spirotetramat-enol are <1 day.  The aerobic soil metabolism half-life of spirotetramat-ketohydroxy is 12.38 days.  Once the field is flooded, for the total toxic residues (i.e., spirotetramat, spirotetramat-enol and spirotetramat-ketohydroxy), the concentration will be reduced only slowly through degradation by aerobic aquatic metabolism (aerobic aquatic metabolism is ~1 day for the parent, ~81 days for spirotetramat-enol, and could not be evaluated for spirotetramat-ketohydroxy and is thus, considered persistent), and by aquatic photolysis in clear, shallow water (aqueous photolysis is 14.4 day for the parent, but no data on degradation for the TTR, spirotetramat-ketohydroxy could be persistent to that route).

      Assuming that the field remains dry for one day and that aerobic soil metabolism takes place during that time, the peak (acute) EDWCs for spirotetramat would be reduced potentially from 395 ppb to around 373 ppb, and will decrease thereafter slowly through aerobic aquatic metabolism.  The annual average would be ~214 ppb.  If the field remains dry for two days pre-flood and aerobic soil metabolism takes place during that time, the peak (acute) EDWCs for spirotetramat would be reduced potentially from 395 ppb to around 353 ppb, and will decrease thereafter slowly through aerobic aquatic metabolism.  The annual average would be ~202 ppb.
      
      In the aqueous photolysis study, using sterile water, spirotetramat-ketohydroxy was not an observed degradate.  If one assumes that the half-life for the enol and the ketohydroxy are similar to the one for the parent (with a half-life of the order of 14.4 Phoenix, AZ days), the 1 year mean value would be of the order of 22 ppb.  See the Figure 1.
      
                                          
                                       
Figure 1. Spirotetramat Concentration vs. Time for Watercress Use Taking Into Account Aqueous Photolysis of the Parent Compound

      3. Dilution and Flow of Receiving Waters from Cultivated Areas

      The amount of pesticide which reaches a moving body of water will be removed in the field under actual conditions of watercress cultivation.  This would be expected to occur likely at the end of the season, downstream from the site at which it is applied by advection in the flowing water.  The rate of removal depends on the rate of flow through the site.  River/stream velocity varies from day to day based on the volume of flow and changing cross-sectional area.  Typical ranges of velocity vary from zero (at the time of tidal flow direction change) to 7 miles per hour.  The pesticide in the flowing water will also spread from the center of mass during the flow.  Table I.B presents the distance downstream of the center of mass of the applied spirotetramat after a period of one day for flow rates up to 3 mph.  Figure 2 shows a conceptualization of a receiving flowing water body of water getting effluents from a watercress field.  It is also noted that some receiving bodies of water might not be flowing, such as in the case of ponds and reservoirs.  In such instances, dilution would be the primary process occurring.
      
Table I.B. Downstream Movement from Site of Application of Spirotetramat in Flowing Water in One Day
                              Flow Rate (ft/sec)
                               Flow Rate (mph) 
                           Downstream Distance (mi)
                                      0.1
                                      0.1
                                      3.5
                                      0.2
                                      0.3
                                      7.0
                                      0.6
                                      0.9
                                     21.1
                                      1.0
                                      1.5
                                     35.2
                                      1.4
                                      2.1
                                     49.3
                                      1.8
                                      2.6
                                     63.4
                                      2.2
                                      3.2
                                     77.4
      
                                       
          Figure 2. Conceptual Model of a Flowing Water Body of Water
              Receiving Effluent from a Treated Watercress Field

      4. Modeling Spirotetramat-ketohydroxy Only

      Besides degradation, one could assume that the only species occurring in the field would be spirotetramat-ketohydroxy.  The reason is the relatively short aerobic half-lives of the parent compound and of spirotetramat-enol.  If that is the case, the EDWCs will be smaller because spirotetramat-ketohydroxy molecular weight is smaller than for the parent compound.  As a result, the predicted EDWCs would be proportionally reduced.  If the transformation of spirotetramat to spirotetramat-ketohydroxy is quantitative, the seasonal equivalent "application rate" would be as follows:
      
      Rate = (0.40 lb parent/A) (317.39 g spirotetramat-ketohydroxy/mol) / (373.45 g parent/mol)
      Rate = 0.34 lb spirotetramat-ketohydroxy/A/season

      This value is ~15% smaller than the one modeled using the application rate for the parent.

C. Conclusions for Surface Waters

      In conclusion, the Tier 1 Rice Model v.1.0 is conservative.  It is apparent that the combination of crop interception, pesticide degradation, stream flow, and runoff dilution from the areas in the watershed which are not treated (see Tables I.A and I.B), has the potential to reduce the conservative EDWCs provided in Table 1-1.

                                  Appendix II
                               Groundwater EDWCs

      Bananas are also considered a minor use.  "US banana production is very limited; in 2009, US total banana production reached almost 7,000 mmt, or 0.01% of the total world production, on an estimated 16,000 acres.  Hawaii is by far the largest banana producer in the United States, followed by Florida."  The NASS shows, however, that the banana acreage in HI in 2008 was only 1,300 A.
      
      The modeling approach for groundwater calculations was described in the previous DWA (DP Barcode D345275, dated 01/22/2008).  Thus, focus is placed only in the changes related to the application rate.  The application rates are calculated in the same way (see sample calculation of the application rate in the previous DWA).  The tables of input parameters follow.

A. Input Values for Groundwater

Tables II.A, II.B and II.C provide the input parameter values in SCI-GROW, in modeling groundwater.

Table II.A. SCI-GROW (v2.3) input parameter values for spirotetramat use on bananas and plantains[1] 
                               PARAMETER (units)
                                   VALUE(S)
                                    SOURCE
                                    COMMENT
Maximum Application Rate
(lb a.i./A)
                                     0.25
                                Proposed label.
Maximum single application rate in five applications on bananas and plantains.
Number of Applications per Year
                                       5
                                Proposed label.
                                       - 
Organic Carbon Partition Coefficient (Koc; mL/g)
                                      237
         OECD Monograph Annex B. Spirotetramat. B.8 Fate and Behaviour
Represents the median of five values as follows: 184, 437, 201, 385, 237 mL/gOC for the parent compound (KOC does not show more than a three-fold variation among values).
Aerobic Soil Metabolism Half-life (days)
                                     0.25
                                       
Represents the median value, since there are four or more values (FL SL, t1/2 = 0.30 days; SL, t1/2 = 0.24 days; SiL, t1/2 = 0.26 days; Si, t1/2 = 0.09 days).
1 Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides; Version 2.1, 10/22/2009 (http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm 07/17/12).

Table II.B. SCI-GROW (v2.3) input parameter values for transformation product spirotetramat-enol use on bananas and plantains[1] 
                               PARAMETER (units)
                                   VALUE(S)
                                    SOURCE
                                    COMMENT
Maximum Application Rate
(lb a.i./A)
                                     0.202
                                Proposed label.
It is assumed that the transformation is quantitative in the aerobic soil metabolism study.  Maximum concentration observed in the aerobic soil metabolism study or 100% by application rate by mole ratio =                                                                                                                        (1.00)(0.25)(301.39/373.45) = 0.202 lb a.i./A for bananas and plantains
Number of Applications per Year
                                       5
                                Proposed label.
                                       - 
Organic Carbon Partition Coefficient (Koc; mL/g)
                                      27
         OECD Monograph Annex B. Spirotetramat. B.8 Fate and Behaviour
Represents the lowest of four values as follows: 27, 65, 29 and 99 mL/gOC for the parent compound (there is greater than a three-fold variation among values).
Aerobic Soil Metabolism Half-life (days)
                                     0.035
                                       
Represents the median value, since there are four or more values (FL SL, t1/2 = 0.30 days; SL, t1/2 = 0.02 days; SiL, t1/2 = 0.16 days; Si, t1/2 = 0.02 days).  It is noted that there is more than 5-fold difference from the lowest to the highest values.
1 Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides; Version 2.1, 10/22/2009 (http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm 07/17/12).

Table II.C. SCI-GROW (v2.3) input parameter values for transformation product spirotetramat-ketohydroxy use on bananas and plantains[1] 
                               PARAMETER (units)
                                   VALUE(S)
                                    SOURCE
                                    COMMENT
Maximum Application Rate
(lb a.i./A)
                                    0.0510
                                Proposed label.
Maximum concentration observed in the aerobic soil metabolism study by application rate by mole ratio =                                                                                                                        (0.240)(0.25)(317.39/373.45) = 0.0510 lb a.i./A for bananas and plantains 
Number of Applications per Year
                                       5
                                Proposed label.
                                       - 
Organic Carbon Partition Coefficient (Koc; mL/g)
                                     48.1
         OECD Monograph Annex B. Spirotetramat. B.8 Fate and Behaviour
Represents the median of five values as follows: 43.1, 48.1, 42.0, 99.7 and 93.7 mL/gOC for the parent compound (there is less than a three-fold variation among values).
Aerobic Soil Metabolism Half-life (days)
                                     4.65
                                       
Represents the median value, since there are four or more values (FL sandy loam, t1/2 = 16.7 days; Sandy loam, t1/2 = 4.2 days; Silt loam, t1/2 = 5.1 days; Silt, t1/2 = 1.5 days).  There is more than 5-fold difference from the lowest to the highest values.
1 Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides; Version 2.1, 10/22/2009 (http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm 07/17/12).

B. Resulting Values for Groundwater

Table II.D summarizes the groundwater estimates from SCI-GROW.  For the total residues (spirotetramat, spirotetramat-enol and spirotetramat-ketohydroxy) the EDWC, suitable for acute and chronic exposure, is 1.24 x 10[-][3] ppb.

Table II.D.  Maximum Tier I Estimated Drinking Water Concentrations (EDWCs) for drinking water risk assessment based on aerial application on bananas and plantains at 1.25 lb a.i./A/season
                         Drinking Water Source (Model)
                               Type of Exposure
            ESTIMATED DRINKING WATER CONCENTRATION  (EDWC)  ( ppb)
                                       
                                       
                                 Spirotetramat
                              Spirotetramat-enol
                           Spirotetramat-ketohydroxy
                                Total Residues
                            Ground-water (SCI-GROW)
                               Acute and Chronic
                                 7.06 x 10[-5]
                                 5.15 x 10[-5]
                                 1.12 x 10[-3]
                                 1.24 x 10[-3]

C. Output Files from SCI-GROW

 

                          SCIGROW
                          VERSION 2.3
            ENVIRONMENTAL FATE AND EFFECTS DIVISION
                 OFFICE OF PESTICIDE PROGRAMS
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                        SCREENING MODEL
                FOR AQUATIC PESTICIDE EXPOSURE
 
 SciGrow version 2.3
 chemical:Spirotetramat
 time is  5/29/2012  11: 7: 9
 ------------------------------------------------------------------------
  Application      Number of       Total Use    Koc      Soil Aerobic
  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)
 ------------------------------------------------------------------------
      0.250           5.0           1.250      2.37E+02        0.2
 ------------------------------------------------------------------------
 groundwater screening cond (ppb) =   7.06E-05 
 ************************************************************************

                           SCIGROW
                          VERSION 2.3
            ENVIRONMENTAL FATE AND EFFECTS DIVISION
                 OFFICE OF PESTICIDE PROGRAMS
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                        SCREENING MODEL
                FOR AQUATIC PESTICIDE EXPOSURE
 
 SciGrow version 2.3
 chemical:Spirotetramat(enol)
 time is  5/29/2012  11: 9:58
 ------------------------------------------------------------------------
  Application      Number of       Total Use    Koc      Soil Aerobic
  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)
 ------------------------------------------------------------------------
      0.202           5.0           1.010      2.70E+01        0.0
 ------------------------------------------------------------------------
 groundwater screening cond (ppb) =   5.15E-05 
 ************************************************************************
 

                          SCIGROW
                          VERSION 2.3
            ENVIRONMENTAL FATE AND EFFECTS DIVISION
                 OFFICE OF PESTICIDE PROGRAMS
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                        SCREENING MODEL
                FOR AQUATIC PESTICIDE EXPOSURE
 
 SciGrow version 2.3
 chemical:Spirotetramat-keto(hydroxy)
 time is  5/29/2012  11:11:52
 ------------------------------------------------------------------------
  Application      Number of       Total Use    Koc      Soil Aerobic
  rate (lb/acre)  applications   (lb/acre/yr)  (ml/g)   metabolism (days)
 ------------------------------------------------------------------------
      0.051           5.0           0.255      4.81E+01        4.7
 ------------------------------------------------------------------------
 groundwater screening cond (ppb) =   1.12E-03 
 ************************************************************************

                                 Appendix III
                             Use Characterization

      Table IIIA is a summary of all agricultural use patterns for spirotetramat in the labels for BYI 8330 150 OD Insecticide (oil dispersion, Reg. No. 264-1051), MOVENTO[(R)] SC (suspension concentrate, Reg. No. 264-1050), and the ULTOR(R) (suspension concentrate, Reg. No. 264-1075).  The uses shaded yellow are the proposed new ones while the uses bold and underlined are the modeled ones.

Table IIIA.  Summary use information for spirotetramat based on labels for BYI 8330 150 OD Insecticide), MOVENTO[(R)] and ULTOR[(R)].  The new uses are shaded yellow.
                                      USE
                  SINGLE  APP. RATE             (lb. a.i./A)
                                NUMBER OF APPS.
                        SEASONAL APP. RATE (lb. a.i./A)
                         INTERVAL BETWEEN APPS. (days)
                                  APP. METHOD
                                  PHI (days)
Soybean
                                     0.08
                                       2
                                     0.16
                                       7
                                     G*, A
                                      21
Tropical Fruits (acerola, avocado, black sapote, canistel, feijoa, guava, longan, lychee, mamey sapote, mango, papaya, passionfruit, persimmon, pulasan, rambutan, sapodilla, Spanish lime, star apple, starfruit, wax jambo, white sapote, jaboticaba)
                                     0.16
                                       3
                                     0.40
                                      14
                                G*, A, Airblast
                                       1
Legume Vegetables (Crop Group 6, except dry soybean) (Edible Podded and Succulent Shelled Pea and Bean and Dried Shelled Pea and Bean
Bean (Lupinus spp., including grain lupin, sweet lupin, white lupin, and white sweet lupin)
Bean (Phaseolus spp., including field bean, kidney bean, lima bean, navy bean, pinto bean, runner bean, snap bean, tepary bean, wax bean)
Bean (Vigna spp., including adzuki bean, asparagus bean, blackeyed pea, catjang, Chinese longbean, cowpea, Crowder pea, moth bean, mung bean, rice bean, Southern pea, urd bean, yardlong bean)
Pea (Pisum spp. including dwarf pea, edible-pod pea, English pea, field pea, garden pea, green pea, snow pea, sugar snap pea)
Other Beans and Peas (Broad bean (fava), Chickpea (garbanzo bean), Guar, Jackbean, Lablab bean (hyacinth bean), Lentil, Pigeon pea, soybean (immature seed), Sword bean) 
                                     0.08
                                       2
                                     0.16
                                       7
                                   G*, A, C
    1 edible podded, succulent beans and peas; 7 dry shelled beans and peas
Globe artichoke
                                     0.12
                                      ~5
                                      0.5
                                       7
                                    G, A, C
                                       3
Citrus Fruit (Crop Group 10-10, including, calamondin, citrus citron, citrus hybrids like chironja, tangelo and tangor, grapefruit, kumquat, lemon, lime, mandarin or tangelo, sweet and sour orange, pummelo, Satsuma mandarin, Australian lime (desert, finger, and round), Brown River finger lime, Japanese summer grapefruit, Mediterranean mandarin, Mount White lime, New Guinea wild lime, Russell River lime, sweet lime, Tachibana orange, Tahiti lime, Trifoliate orange, uniq fruit, including cultivars, varieties and/or hybrids of these commodities)
                                     0.16
                                       2
                                     0.32
                                      21
                                G*, A, Airblast
                                       1
Grape and Small Fruit Vine Climbing Crop Subgroup 13-07F (except Fuzzy kiwifruit/ includes grape, gooseberry, maypop, Schisandra berry, hardy kiwifruit)
                                     0.13
                                       2
                                      0.2
                                      30
                                G*, A, Airblast
                                       7
Pome Fruit (Crop Group 11-10, including apple, crabapple, loquat, mayhaw, pear, Asian pear, quince, azarole, Chinese quince,  Japanese quince, medlar, tejocote, hybrids, cultivars and/or varieties of these)
                                     0.14
                                       3
                                      0.4
                                      14
                                G*, A, Airblast
                                       7
Stone Fruit (Crop Group 12, including apricot, sweet and tart cherry, nectarine, peach, plum-various kinds, plumcot, and fresh and dried prune)
                                     0.14
                                       2
                                     0.24
                                      14
                                G*, A, Airblast
                                       7
Tree Nuts (Crop Group 14 plus pistachio, including almond, beechnut, Brazil nut, butternut, cashew, chestnut, chinquapin, filbert or hazelnut, hickory nut, macadamia nut or bush nut, pecan, pistachio, black walnut, and English or Persian walnut)
                                     0.14
                                       3
                                     0.34
                                      14
                                G*, A, Airblast
                                       7
Hops
                                     0.10
                                       2
                                      0.2
                                      14
                                G*, A, Airblast
                                       7
Christmas Tree Plantations
                                     0.16
                                       2
                                     0.32
                                      14
                                G*, A, Airblast
                                      N/A
Fruiting Vegetables (Crop Group 8-10 including eggplant, groundcherry, okra, pepinos, bell and non-bell pepper (cayenne, chili pepper, habanero, jalapeno, pablano, pimento and serranero), tomatillo, tomato, African eggplant, Bush tomato, cocona, currant tomato, garden huckleberry, goji berry, martynia, naranjilla, pea eggplant, roselle, scarlet eggplant, sunberry, tree tomato, including varieties and/ or hybrids of these commodities)
                                     0.08
                                       2
                                     0.16
                                       7
                                    G, A, C
                                       1
Leafy Vegetables (Crop Group 4 including amaranth-various kinds, arugula-roquette, cardoon, celery, celtuce, chervil, Chinese celery, chrysanthemum, corn salad, garden cress, cress-various kinds, dandelion, sorrel dock, endive, Florence fennel, lettuce-head and leaf, orach, parsley, garden and winter purslane, radicchio or red chicory, rhubarb, spinach-various kinds, Swiss chard, taro leaves)
                                     0.08
                                       2
                                     0.16
                                       7
                                    G, A, C
                                       3
Brassica (Cole) Leafy Vegetables (Crop Group 5 including broccoli, broccoli raab, Brussels sprouts, cabbage, cauliflower, cavalo broccolo,  Chinese broccoli, Chinese cabbage (bok choy), Chinese cabbage (napa), Chinese mustard cabbage (gai choy), collards, kale, kohlrabi, mizuna, mustard greens, mustard spinach, rape greens)
                                     0.08
                                       2
                                     0.16
                                       7
                                    G, A, C
                                       1
Potato and Other Tuberous and Corm Vegetables (Crop Subgroup 1C including arracacha, arrowroot, Chinese and Jerusalem artichoke, edible canna, bitter and sweet cassava, chayote-root, chufa, dasheen or taro, ginger, leren, potato, sweet potato, tanier, turmeric, yam bean, true yam)
                                     0.08
                                       2
                                     0.16
                                       7
                                    G, A, C
                                       7
Bushberry and Low Growing Berry Subgroups (Crop Subgroups 13-07B and 13-07H including aronia berry, bearberry, bilberry, blueberry (highbush and lowbush), Chilean guava, cloudberry, cranberry, currant (black, buffalo, native, and red), elderberry, European barberry, gooseberry, edible honeysuckle, jostaberry, Juneberry, muntries, lingonberry, Partridgeberry, salal, sea buckthorn, and cultivars, varieties, and/or hybrids of these)
                                     0.16
                                       3
                                     0.47
                                       7
                                G*, A, Airblast
                                       7
Watercress
                                      0.2
                                       2
                                      0.4
                                       7
                                    G, A, C
                                       3
Banana and Plantains
                                     0.25
                                       5
                                     1.25
                                      14
                                G*, A, Airblast
                                       1
Coffee
                                     0.16
                                       3
                                     0.47
                                      21
                                G*, A, Airblast
                                      14
Pineapple
                                     0.16
                                       2
                                     0.32
                                      14
                                G*, A, Airblast
                                       1
Pomegranate
                                     0.16
                                       2
                                     0.32
                                      14
                                G*, A, Airblast
                                       1
Bulb Vegetables
Crops of Crop Subgroup 3-07A (including: daylily (bulb), fritillaria (bulb), garlic (bulbs of common, great-headed, serpent), lily (bulb), onion (bulbs of common, Chinese, pearl, potato onion), shallot (bulb), plus cultivars, varieties, and/or hybrids of these);
Crops of Crop Subgroup 3-07B, (including: Chinese chive (fresh leaves), chive (fresh leaves), elegans hosta, fritillaria (leaves), kurrat, leek (Allium porrum, Lady's, wild), onion (Beltsville bunching, fresh, green, macrostem, tree [tops], welsh [tops]), shallot (fresh leaves), plus cultivars, varieties, and/or hybrids of these)
                                     0.08
                                       2
                                     0.16
                                       7
                                    G, A, C
                                3 for CS 3-07A;
                                7 for CS 3-07B
*High air velocity, low volume or air curtain sprayers; G = ground; A = aerial; C = chemigation