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 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION **UNITED ST AT**  **ES ENVIRONMENT AL**  **PROTECTION A GENCY** 

**WA SHINGTON**  **, D.C. 20460**

**PC Code: 099050**  **DP Barcode :**  **D 423299**  **Dat e:**  **March 25**  **, 201 5**  **MEMORANDUM SUBJECT**  : Tier I Drinking Water Exposure Assessment for Acetamiprid in Regards to a Proposed

Reduction in the Preharvest Interval for Clover and Hay **TO:** Sidney Jackson, Risk Manager

Barbara Madden, Minor Use Team Leader Minor Use and Emergency Response Branch Registration Division (7505P) J acquelyn Marchese , Risk Manager Venus Eagle, Product Manager Meredith Laws, Branch Chief Invertebrate - Vertebrate Branch 3 Registration Division (7505P) Elizabeth Holman, Physical Scientist Christina Swartz, Branch Chief Risk Assessment Branch 2 Health Effects Division (7509P) **FROM:** Katrina White , Ph.D., Environmental Scientist

Environmental Risk Branch IV Environmental Fate and Effects Division (7507P ) **REVIEWED** Cheryl Sutton , Ph . D . , Environmental Scientist **BY:** Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P ) **APPROVED** Jean Holmes , D.V.M., M.P.H., Branch Chief **BY:** Environmental Risk Branch IV

Environmental Fate and Effects Division (7507P ) **1 EXECUTIVE SUMMARY**  A screening - level drinking water assessment (DWA) for acetamiprid ( PC Code 099050, (E ) - N1 - [(6 - chloro - 3 -pyridyl)methyl] - N 2 - cyano - N1 - methylacetamidine ; CAS No. 135410 - 20 - 7 ) was conducted in sup port of the proposed reduction of preharvest intervals (PHI) for the use of acetamiprid for control of a variety of insects on clover and hay. The new proposed PHI is 30 days. A drinking water assessment was requested in support of this action because new models (Pesticide Root Zone Model GroundWater,

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PRZM - GW) and new data (an aerobic aquatic metabolism study, MRID 49034201) have become available since the last drinking water assessment was completed. Additionally, cranberries is modeled with the Provisional Cranberry Model. The Food Quality Protection Act Index Reservoir Screening Tool (FIRST) and the Provisional Cranberry Model w ere used to generate surface water Estimated Drinking Water Concentrations ( EDWCs ) for use in the human health dietary risk assessment, while the Pesticide Root Zone Model for Groundwate r ( PRZM GW ) and Sc reening Concentration in GroundWater ( SCI - GROW ) models were used to generate groundwater EDWCs. Consistent with previous drinking water assessments, the residues of concern (ROC) for acetamiprid were the parent compound and unextracted residues (USEPA, 2001, 2011, D394234, D394479) . For surface water sources of drinking water, the peak and annual average EDWC s associated with acetamiprid are 81.5 and 32.2 μg/L , respectively . For groundwater sources of drinking water, the peak and annual average EDWCs associated with acetamiprid are 49.7 and 45 μg/L, respectively. Selected modeling results files are provided in **Appendix A**  . Maximum EDWCs for acetamiprid residues in surface water and groundwater are presented in **Table 1**  . T 

### he maximum EDWC values recommended for use in the human health dietary risk assessment are **81.5 μg/L**  for acute EDWC and **45 ug/L**  for chronic and cancer EDWCs . The acute value was generated for surface water sources of drinking water using FIRST and the chronic value was generated for ground water sources of drinking water using PRZM - GW . C omplete modeling results are presented in **Table 10**  and **1 1**  . **Table 1**  **. Tier I EDWCs for drinking water**  **exposure assessment based on acetamiprid and**  **unextracted residues use a s a bait scattered on surfaces**  **and on cranberrie s**  **1,2 Source of Drinking Water**  **(M odel)**  **Acetam iprid**  **and unextracted residue concentration in drinking water**  **( μg/L)**  **Bait Scattered on Surfaces**  0.082 lbs a.i./A, 24x, 3 day interval ,

ground **Cranberries 3**  0.13 lbs a.i./A, 2x, 7 - day interval ,

aerial Surface water (FIRST and Provisional Cranberry Model ) **A cute:**  **81.5** Annual average: 14.6 A cute: 88.3 Annual average: 32.2 Groundwater (PRZM - GW) Daily peak: 49.7 **Post breakthrough ave: 45**  -- 1 The highest EDWCs for the proposed and previously evaluated use scenarios are shown in **purple** . 2 Previously estimated acute and annual average surface water concentrations were 95.2 and 26.6 μg/L, respectively. Previously estimated groundwater concentrations were 0.04 μg/L and were estimated using SCIGROW . 3 EDWCs were calculated using the Provision al Cranberry Model. This assessment is based on available environmental fate data. There were a number of uncertainties associated with this drinking water exposure assessment. The major uncertainty is the maximum number of applications for the scatte r bait use. A maximum of 24 application s was assumed because there was not a specified number of maximum applic ations on the label. Another source of uncertainty in the assessment is the inclusion of unidentified, unextracted residues in the calculation of aerobic soil metabolism half

- lives. For the scenarios resulting in the highest EDWC s in surface water , inclusion of unextracted residues in half - life calculations resulted in EDWCs that are 1 4 to 43 times EDWCs based on

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par ent alone. Therefore, the identity of the unextracted residues results in a significant uncer tainty in the risk assessment. Finally, all models used were screening - level models. Acetamiprid has not been identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act 1

. Additionally, human health advisories and drinking water standards 2 have not been developed for acetamiprid. Human health benchmarks for Pesticides 3 (HHBP) have been established for acetamiprid, as follows:

 Acute or One - day HHBP = 1000 μg/L (Children)  Chronic or Lifetime HHBP (Noncancer) = 497 μg/L (General Population) **2 PROBLEM FORMULATION**  This is a screening - level drinking water assessment (DWA) that uses modeling t o estimate surface water and groundwater concentrations of pesticides in drinking water source water (pre - treatment) , resulting from pesticide use on sites that are expected to be vulnerable to runoff and/ or leaching . Screening - level DWAs are designed to eliminate the need for further scrutiny of chemicals with low potential for posing drinking water concern s . The current proposed action is to reduce the preharvest interval for clover and hay. This is not expected to alter the EDWC s for acetamiprid; however, new models were available since the last drinking water assessment was completed. Therefore, modeling was updated using the most up to - date models (PRZM - GW an d the Provisional Cranberry Model). Additionally, new aerobic aquatic metabolism data (MRID 49034201) were available and used in modeling. **3 ANALYSIS**  3.1 Use Characterization Acetamiprid use patterns were summarized based on the Registration Review Problem F ormulation (USEPA, 2012, DP Barcode 40 1171) and the most recently completed drinking water assessment (USEPA, 2011, D394234, D394479) . Acetamiprid is a neonicotinoid insecticide used to control a variety of insects on agriculture, residential, commercial, industrial, and nursery use sites. Formulations include water dispersible granules (WDG), emulsifiable concentrates (EC), soluble concentrates (SC), liquids, water soluble packets (WSP), impregnated stickers, impregnated bait stations, gels, and an attract - and - kil l device. Water dispersible granules, EC, SC, and WSP are applied as ground or aerial sprays and may result in spray drift. Gels are used as spot treatments, beads, and thin films to control ants and cockroaches. Water dispersible granules are all applie d as a liquid. There are also seed treatment uses on potatoes, canola, and mustard. Some liquid formulations are injected into trees. Termiticides may be applied as a liquid or foam. They may be applied on soil surfaces as a perimeter treatment, crack and crevice treatment, or brush and spray. The y may also be applied into soil using trenching, rodding, sub slab injection, and soil excavation techniques. Some termiticide products are applied to subsurfaces into piping, injections, and reticulation del ivery systems. The impregnated materials are generally stickers used to control flies. The attract - and - kill device is a pheromone mixed with acetamiprid that is hung in trees. **Table 2**  summarizes the use patterns modeled in this drinking water assessment. The use patterns modeled were chosen because they are expected to result in maximum EDWC s based on previous drinking water assessments and/or the availability of new models used in estimating exposure. 1 http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T#causes_303d 2 http://water.epa.gov/drink/standards/hascience.cfm 3 http://iaspub.epa.gov/apex/pesticides/f?p=HHBP:home:16658387747054:::::

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**Table 2**  **. Summary of use patterns modeled in this drinking water assessment**  **Use Max. Single** 

**App Rate lbs a.i./A**  **(kg a.i./ha) Max.**  **Annual**

**App. Rate lbs a.i./A**  **(kg a.i./ha) Max** 

**Number of Applications**  **Minim um** 

**Retreatm ent**  **Interval (days)**  **Application**

**Type** Scatter Bait 0.082

(0.092) 1.97

(2.20) 24 3 Ground boom Tree Nuts 0.18

(0.20) 0.72

(0.80) 4 14 Aerial Cranberries 0.13

(0.15) 0.26

(0.29) 2 7 Aerial Source: Previous Drinking Water Assessment (USEPA, 2011, D394234, D394479) **4 ENVIRONMENTAL FATE AND TRANSPORT CHARACTERIZATION**  Acetamiprid may be transported to surface water and ground water via runoff, leaching, and spray drift. Acetamiprid is classified as moderately mobile using the Food and Agriculture Organization ( FAO ) classification system (KOC s = 157 to 298 L/kg OC). Th e primary route of degradation is aerobic soil metabolism. Unextracted residues made up a significant amount of radioactivity and the identity of the residues is unknown in metabolism studies. Therefore, degradation rates were estimated both for the pare nt alone and assuming that unextracted residues were the parent. Aerobic soil metabolism rates for the parent ranged from <1 day to six days for the parent and two to 99 days for the parent plus unextracted residues in nine soils (USEPA, 2011, D390070) . Aerobic aquatic me tabolism rates were slower at 23 to 32 days for the parent alone and 38 to 74 days for parent plus unextracted residues in three sediment s (MRID s 44988513 and 49034201 ). Anaerobic aquatic metabolism was much slower , with a half - life of 325 days in a loamy sand sediment (MRID 44988512). Acetamiprid is stable to hydrolysis at 25 o C , but does undergo aqueous photolysis (half - life = 34 days). Based on the low log octanol -water partition coefficient ( log K ow = 0.08 at 25 o C), acetamiprid is not expected to bioconcentrate. **Table 3**  summarizes the identity information and physical - chemical properties of acetamiprid. **Table 4**  summarizes other environmental fate data for the parent and provides half - lives for the parent and unextracted residues. **Table 3**  **. Summary of physical -**  **chemical properties of acetamiprid Param**  **eter Value**  **Source Comments**  PC Code 099050 None None CAS Number 135410 - 20 - 7 (USNLM, 2009) None Structure None Chemical Name N 1

- [(6 - chloro - 3 - py ridyl)methyl] - N 2

- cyano N 1

- methylacetamidine MRID 44651803 None Molecular Weight 222.68 MRID 44651803 None

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**Param eter**  **Value Source**  **Comments** Water Solubility 4250 mg/L (25°C) MRID 44651811 None Vapor Pressure <1 x 10 - 8 Torr at 25 o C MRID: 46235701 Nonvolatile from dry non - adsorbing surfaces (USEPA, 2010a) 7.50 x 10 - 10 Torr at 25 o C 1 X 10 - 4 mP a at 25 o C (AERU, 2009) Henry’s Law constant 5.2 x 10 - 14 atm - m 3 /mol at 25 o C (estimated) (Estimated from vapor pressure and water solubility at pH 7 and 20 o C) Calculated with vapor

pressure reported by AE RU (2009). Dissociation Constant (pKa) 0.7 at 25 o C (USEPA, 2002) None Log KOW 0.8 at 25 o C MRID 44651883 Not likely to bioconcentrate (USEPA, 2010a) 1 All estimated values were estimated according to “ Guidance for Reporting on the Environmental Fate and Transport of the Stressors of Concern in Problem Formulations for Registration Review, Registration Review Risk Assessments, Listed Species Litigation Assess ments, New Chemical Risk Assessments, and Other Relevant Risk Assessments ” (USEPA, 2010a) . **Table 4**  **. Summary of environmental fate and transport properties of**  **acetamiprid 5**  **Param eter**  **Value(s)**

**Parent (Value for acetam iprid**  **plus unextracted residues) Source**  **Comments** Hydroly sis Half

life 3 (day s) Stable (pH 5, 7, 9 at 25 o C)

50.8 (pH 9 at 35 o C) 12.8 (pH 9 at 45 o C) MRID 44651876 None Atmospheric Degradation Half

life (days) 0.140 (estimated) (USEPA, 2009a) NA Estimated Hydroxyl Radical Reaction Half - life for a 12 - hour day; 1.5x10 6 OH molecules/cm 3 Using EPIWeb Version 4.0 Aqueous Photolysis Half - life (days) 34 2 (pH 7, 25 o C) MRID 44988509 None Soil Photolysis Half

life No half - lives available MRID 48563501 The study provides evidence on degradation

products that may be observed with irradiation.

Aerobic Soil Metabolism Half

life (days) 20 o C:

1.1 (76), sandy loam 1.2 (75), clay loam 1.0 (99), clay loam MRID 46255603 Only one replicate. Unextracted residues made

up <1 to 31 % of applied radioactivity. 20 o C: 2.8, sandy loam 0.90, silty clay loam 6 (10), clay loam MRID 44651881 Foreign soils. Unextracted residues made up

approximately 20 - 40% at the end of the study (182 days); however, unextracted residues were not observed until most of the parent had degraded in the silty clay loam and sandy loam suggesting that the unextracted residues were not the par ent compound. 4 20 o C: 1.4 (2.0), loamy sand MRID 44699101 Foreign soils. Unextracted residues ranged

from 2 to 17% of applied radioactivity.

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**Param eter**  **Value(s)**

**Parent (Value for acetam iprid**  **plus unextracted residues) Source**  **Comments** 25 o C: 3.5 (6.4), loamy sand MRID 44651879 Biphasic degradation was observed with an

initial 3.6 day half

- life followed by a 75 day half - life. Unextracted residues were up to

20%. Anaerobic Soil Metabolism Half

life (days) No half - lives available MRID 48554501 Dissolved oxygen concentrations ranged from

1.87 - 1.94 mg/L, indicating system was not fully anaerobic. Data on degradates can be used as the environment is expected to occur in

natural systems. Aerobic Aquatic Metabolism Half

life or DT 50 (days) 25 o C:

25 (74), loamy sand sediment MRID 44988513 Maximum of 38% unextracted residues. 20 o C: 23 (59, IORE), loam sediment 32 (38, IORE), clay loam sediment MRID 49034201 Maximum of 43% unextracted residues. Anaerobic Aquatic Metabolism Half

life (days) 25 o C:

325 (568), loamy sand sediment MRID 44988512 Data available for only one sediment. Solid - water distribution coefficient (Kd) in L/kg 20 o C:

0.39, loamy sand, pH 4.4 3.9, loamy sand II, pH 6.2 1.1, silt loam, pH 6.6 3.5, clay, pH 7.5 4.1, sandy loam sediment, pH 5.6 Mean = 2.60 MRID 44651883 Coefficient of variation is 66%.

Freundlich solid water distribution coefficient (KF ) in L/kg 20 o C:

0.33, loamy sand, pH 4.4 3.0, loamy sand II, pH 6.2 1.0, silt loam, pH 6.6 3.2, clay, pH 7.5 3.2, sandy loam sediment, pH 5.6 MRID 44651883 Sorption was dependent on concentration in some soils. Organic - carbon normalized distribution coefficient (Koc ) in L/kg org anic carbon 20 o C:

157, loamy sand, pH 4.4 266, loamy sand II, pH 6.2 251, silt loam, pH 6.6 298, clay, pH 7.5 164, sandy loam sediment, pH 5.6 Mean = 227 MRID 44651883 Coefficient of variation is 28%. The

coefficient of variation is less than that for Kd values indicating that Koc values will be better at predicting sorption across soils than Kd values. Moderately mobile according to FAO

classification.

Terrestrial Field Dissipation Half

- life (days) 2.8, CA, Gilman loamy fine, Vinca

rosea 14.1, FL, Astatula fine, tree ferns 4.2, NJ, Penn silt loam, garden mums MRID 44988514 Wettable powder 70% ai (EXP80667A 70WP).

Degradate IM 1 - 2 converted to IM 1 - 4 in storage stability study and IM 1 - 4 was not stable. Broadcast at 0.15 lbs ai/A with four applications. Parent was not detected below 15 cm . 3, WA, Timerman coarse sandy loam , apples 6, FL, Candler sand soil, oranges 13, NY, Oakville loamy fine sand, cabbage 6, CA, Romona loam soil, cotton MRID 44988515 Wettable powder 70% ai (EXP80667A 70WP).

Degradate IM 1 - 2 converted to IM 1 - 4 in storage stability study and IM 1 - 4 was not stable. Broadca st at 0.15 lbs ai/acre with four applications. Parent was not detected below 15 cm . Conditions not favorable to leaching. Subset of data used to estimate half - life for FL and WA site.

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**Param eter**  **Value(s)**

**Parent (Value for acetam iprid**  **plus unextracted residues) Source**  **Comments** 10.1, Prince Edward Island, Alberry sandy loam 5.2, Ontario, London loam 17.8, Manitoba, Ryerson clay loam MRID 44988625 Wettable powder 70% ai (EXP61486A).

Storage stability data were not submitted for the test site soils. Acetamiprid was applied four times at 168 g ai/ha with a 7 day interval to bare plots in Can ada. Parent not detected

below 15 cm depth. Environmental Chemistry Methods and Independent laboratory Validation LC/MS/MS for detection of

acetamiprid, IM 1 - 2, IC - 0 in soil MRID 44988516/ 44988517 Acetamiprid, IC - 0, IM 1 - 4 LOD = 3.33 μg/kg - soil Acetamiprid, IM 1 - 2, IC - 0, 1M - 1 - 4 LOQ = 10 μg/kg - soil HPLC - UV for parent, IC - 0, IM 1 - 4, IM 1 - 2 in water MRID 44988536 LOD = 0.033 μg/L LOQ=0.1 μg/L ai=active ingredient 1 Degradation kinetics were calculated using the single first order decay equation unless otherwise specified. Two aerobic aquatic metabolism studies used the Indeterminate Order Rate Equation (IORE) to calculate the time to 50% decline of residues (DT 50 ). 2 Value corrected to represent natural sunlight at 40 o N latitude. 3 MRID 446518 77 is supplemental. A material balance was not conducted in the study; however, the results suggest that degradates IM - 1 - 4 and IC - 0 are stable. 4 This indicates that the unextracted residues were not the parent compound. Unextracted residues in the clay loam appeared as the parent was lost the identity of unextracted residues is unknown. 5 This table shows half

- lives for the parent and parent plus unidentified unextracted residues which may or may not be the parent. These values are relevant in understan ding the uncertainty in data due to unextracted residues. **5 RESIDUES OF CONCERN**  The Metabolism Assessment Review Committee (MARC) reported that the residue of concern for acetamiprid is the parent only (USEPA, 2001) . The 2011 “ Tier I Drinking Water Exposure Assessment for the Section 3 New Use of Acetamiprid on Various Agricultural Crops and as a Scatter Bait to Control Insects ” was conducted for acetamiprid and unextracted residues as residues of concern (USEPA, 2011, D394234, D394479) . Therefore, this assessment will also be conducted on acetamiprid and unextracted residues . Unextracted residues were observed in aerobic soil and aerobic aquatic metabolism studies and in some studies it was uncertain whether the unextracted residues w ere parent compound (MRIDs 46255603, 44651881, 44699101, 44651879, 44988513, and 44988512). 4 Additionally, the extraction techniques were not exhaustive and it is likely that if different extraction techniques were used a higher percentage would be extrac ted. Therefore, when it was uncertain, half - lives were estimated assuming the unextracted residues were the parent compound. When the parent was shown to degrade at the beginning of the study and unextracted residues did not appear until the end of the s tudy, it was assumed that the unextracted residues were not the parent compound. This approach is consistent with Guidance for Addressing Unextracted Residues in Laboratory Studies (USEPA, 2014c) .

4 If unextracted residues formed along with loss of the parent compound it is possible that the unextracted residues are the parent compound; however, if the parent degraded significantly in the beginning of the study and unextracted residues did not form until the end of the study, the unextracted residues are unlikely to be the parent compound.

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**6 DRINKING WATER EXPOSURE MODELING**  6.1 Models EDWCs were generated using EFED’s standard suite of models. The FQPA Index Reservoir Screening Tool (FIRST version 1.1.1, March 25, 2008) is a surface water model that is used to estimate both acute and chronic pesticide concentrations in untreated drinking water. EDWCs from FIRST represent concentrations which might occur from a single 1 - in - 10 - year storm event following the last application of pesticide at a location more vulnerable than most locations in the United States to runoff, regardless of the cr op being produced. The model considers reductions in dissolved concentration 1) due to the percentage of the watershed which is cropped (percent cropped area - PCA), 2) due to sorption of pesticide to field soil and to reservoir bottom sediment, 3) due to incorporation of the pesticide at the time of application, 4) due to degradation in soil before runoff to the reservoir, and 5) due to degradation of the pesticide within the water body. Reservoir water concentrations may be increased due to deposition of spray drift into the feeding stream or directly into the reservoir itself. FIRST is designed to mimic a more complex simulation using the linked PRZM3 (Carsel et al. , 1997) and EXAMS 2.97.7 (Burns, 2000) models, but requires less time and effort to complete. A more detailed description of the index reservoir watershed can be found in USEPA, 2010 (USEPA, 2010c) . The FIRST model and users manuals may be downloaded from the U.S. Environmental Protection Agency (EPA) Water Models web -page ( http://www.epa.gov/oppefed1/models/water/#first). Percent Cropped Areas (PCA) that account for the maximum area within a watershed that may be planted with the modeled crop are applied to concentrations predicted by FIRST (USEPA, 2010b, 2 014a) . If a chemical has uses in a variety of land cover classes that include residential areas, a PCA is not applied because the land - class was not included in the development of PCAs (USE PA, 2010b) . Acetamiprid may be used on a variety of landcover classes and a PCA was not applied to the EDWC. The FIRST model assumes spray drift fractions ( as shown in **Table 5**  **)** that are more conservative than the spray drift fraction currently recommended for use in risk assessment (USEPA, 2013b) . The currently recommended spray drift fraction is calculated using the same methodology as that used when FIRST was designed , but uses the most current AgDRIFT model. The new AgDRIFT model results in a slightly di fferent spray drift fraction from that used in the FIRST model . **Table 5**  **. Comparison of FIRST and updated spray drift e stimates**  **Application Type Spray Drift Fraction**  **FIRST Updated Values**  Aerial Spray 0.16 0.125 Ground Spray 0.064 0.062 Airblast 0.063 0.042 Granular 0 0.0 Groundwater EDWCs for were derived using the PRZM - GW model (Pesticide Root Zone Model for GroundWater , version 1.0 7 , Nov., 201 4 ), with the GW - GUI (Graphical User Interface, version 1.0, August 31, 2012). PRZM - GW is a one - dimensional leaching model that estimates the concentrations of pesticides in groundwater. It accounts for pesticide fate in the crop root zone by simulating pesticide transport and degradation through the soil profile after a pesticide is applied to an agricultural field. PRZM - GW permits the assessment of multiple years of pesticide application (up to 100 years) on a single site. Six standard scenarios, each representing a different region known to be vulnerable to groundwater contamin ation, are available for use with PRZM - GW for risk assessment purposes. In PRZM - GW simulations, each of these standard scenarios was used and the highest EDWCs across scenarios is shown in the modeling results section . PRZM - GW output represents pesticide concentrations in vulnerable groundwater located directly beneath an agricultural field, following many years of pesticide application

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( USEPA 2012a, 2012b ). EDWC s in groundwater w ere also estimated using EFED’s groundwater model SCI - GROW (Screening Concentration in Ground Water, version 2.3; 8/8/2003). SCI - GROW is a regression model used as a screening tool to estimate potential pesticide concentrations in vulnerable ground water that might be used as drinking water. SCI - GROW was dev eloped by fitting a linear model to groundwater concentrations with the Relative Index of Leaching Potential (RILP) as the independent variable. Groundwater concentrations were taken from 90 - day average high concentrations from Prospective Ground Water mo nitoring studies; the RILP is a function of aerobic soil metabolism and the soil - water partition coefficient. The output of SCI - GROW represents concentrations that might be expected to occur in shallow unconfined aquifers under sandy soils, which is repre sentative of the groundwater most vulnerable to pesticide contamination likely to serve as a drinking water source ( USEPA 2002 ). The surface water EDWC for cranberries were determined using the Provisional Cranberry Model, this is the Tier 1 Rice Model (v1.0, May 8, 2007) with a modified depth for cranberries 5 and some modification s made to allow for degradation and multiple applications . Some cranberries are grown in bogs, where the field is temporarily flooded to control pests, prevent freezing, and to facilitate harvest. After flooding, water may be held in a holding system, recirculated to other cranberry growing areas, or released to adjacent waterbodies (rivers, streams, lakes, or bays). Introduction of acetamiprid to surface water via flooding o f the bog and release of water is evaluated usin g the Provisional Cranberry Model . T he Provisional Cranberry Model will estimate residues in water that is introduced to the field and not mixed with any additional water. The Provisional Cranberry Model wi ll overestimate exposure to pesticides in drinking water to the extent that drinking source water is not drawn from cranberry bogs. Dilution and microbially - mediated degradation are expected to reduce concentrations in water prior to their movement to the vicinities of drinking water treatment plant intakes. The extent of this reduction in concentrations depends on 1) the length of time the compound is in the water, 2) the distance the water will travel before the drinking water intake, 3) the amount of dilution and 4) whether the water it is mixed with also carries residues of acetamiprid . The Tier 1 Rice model estimates concentrations in a water body holding a 10 cm water depth. When a pesticide is applied to the water, the model employs the assumpti on that the pesticide instantaneously partitions between water and sediment, as determined by the chemical’s sorption coefficient, according to: 

#   d b sed sed w ai w 

### K

d d m C 

 3 2 0 

### 10

' 10

 

###    where, C w0 = initial water concentration [μg/L] mai ' = mass applied per unit area [kg/ha] Kd = water - sediment partitioning coefficient [L/kg] dw = water column depth = 0.10 m d sed = sediment depth = 0.01 m θ sed = porosity of sediment = 0.509 ρ b = bulk density of sediment = 1300 kg/m3

5 Other models may be used to calculate EDWC for use on cranberries ( e.g ., the Surface Water Concentration Calculator and the Pesticides in Flood Agriculture Model). The Provisio nal Cranberry Model was used because it is expected to result in the highest EDWC for this use pattern.

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This simplifies to: And, if appropriate: Kd = 0.01K oc where: C w=water concentration in μg/L mai ’=mass applied per unit area in kg/ha K oc =organic - carbon normalized soil -water distribution coefficient (L/kg - oc) This model was used for this assessment with a modification to the depth of the water body, to reflect concentrations in the water of a cranberry bog rather than that of a rice paddy (Cape Cod Cranberry Growers Association, 2001) . Specifically, in the first equation above, the value of d w (water column depth) was changed to 0.305 m (1 foot), from the usual 0.10 m depth that is assumed for rice paddies. This modification has been used in a previous assessment, to estimate aquatic exposure concentrations for the chemical fenpyroximate (USEPA, 2012, D391431, 2012, D405064) . The concentrat ion in water over time for the Provsional Cranberry Model was based on the following equation: C w, t = C w, 0 e ( - kt) Where Cw, t = the concentration in water at time, t Cw, 0 = the concentration in water at application or time of zero e = base of natural logarithm k = first - order rate constant of degradation or dissipation (1/days) t = time after application (days) When two applications were modeled, the initial concentration in the water after each application was estimated using the Provsional Cranberry Model . Daily concentrations (after the application day) were then determined from the initial concentration by using the aerobic aquatic metabolism rate and the above equation. This was completed for each application. Concentr ations in water from the first and second applications were added to determine the total concentration in water over time for each day. Acute concentrations were reported at the maximum concentration for the given scenario. Chronic concentrations were taken as the average daily concentration over 365 days. **6.2** Input Parameters Input parameters used in modeling are presented in **Tables 6, 7, and 8** . Input parameters were selected in accordance with EFED’s guidance documents (USEPA, 2009b, 2010d, 2012, 2013a, 2013b, 2014b, 2014c; USEPA and Health Canada, 2013) . The uses on agricultural crops allow for ground, aerial, and airbla st applications of a flowable material. The scatter bait is applied as a dry material on surfaces or placed in a bait station and no spray drift is expected with this use. The scatter bait use is evaluated as a granule formulation. For the agricultural crop uses, EDWC for broadcast aerial spray applications were estimated , as these almost always result in

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higher concentrations than a ground or airblast application. In the previous DWA , only o ne aerobic aquatic metabolism half

- life value was available (25 for parent only and 74 days for parent and unextracted residues in a loamy sand; MRID 44988513). These values were multiplied by three to obtain the model input values of 75 and 222 days for FIRST. With the additional submitted ae robic aquatic metabolism study available, the new input was based on the 90 th percentile upper confidence bound on the mean of three values, resulting in an input of 24 days for acetamiprid alone and 99 days for acetamiprid plus unextracted residues. **Ta ble**  **6 .**  **FIRST (v1.1.0) input parameter v alues for**  **a cetamiprid**  **Param eter**  **Value Source**  **Comment** Organic carbon partitioning coefficient (KOC ; mL/g OC) 227 MRID 44651884 Mean of five K OC values. Coefficients of variation (CV) were lower for KOC (CV=28%) as compared to Kd (CV=66%). Aerobic Soil Metabolism Half

- life (days) Parent Only: 2.4 Parent+Unextracted Residues: 39 MRIDs 44655603, 44651881, 44699101, 44651879 The 90 percent upper confidence bound

on the mean of 8 half

- life values. Values were adjusted to 25 o C. Wetted in? No (USEPA, 2011, D394234, D394479) -- Depth of Incorporation (inches) 0 -- Application Parameters See Results Table -- Percent Cropped Area (PCA) 1.0 PCA Guidance (USEPA, 2014b) There are currently registered

residential and rights - of

- way uses. Solubility in Water (mg/L) 4250 MRID 44651811 Measured at 25 o C Aerobic Aquatic Metabolism Half

- life (days) Parent: 24 Parent+ Unextracted Residues: 99 MRID 44988513, 49034201 The 90 th percentile upper confidence

bound on the mean of 3 values. T wo values were adjusted to 25 o C. Hydroly sis Half

- life at pH 7 (days) Stable (0) MRID 44651876 -- Aquatic Photolysis Half - life at pH 7 (days) 34 MRID 44988509 Corrected for continuous irradiation as well as for latitude/season to reflect photolysis in summer sunlight at 40 o N

latitude . **Table 7**  **. SCI**  **- GROW (v2.3) input parameter values for a**  **cetam iprid**  **Param eter**  **Value Source**  **Comments** Koc (mL/g) 251 MRID 44651884 Median of five values. Coefficients of variation (CV) were lower for KOC (CV=28%) as compared to Kd (CV=66%). Aerobic soil metabolism t 1⁄2 (days) Parent Only: 0.92 Parent+Unextracted Residues: 6.7 MRIDs 44655603, 44651881, 44699101, 44651879 The median of 8 half - life values. Values were adjusted to 25 o C.

###  12



**Table 8**  **. Provisional Cranberry**  **Model input p**  **arameters values for acetamiprid**  **Input Parameter Value**  **Source Comments**  Application Rate (lbs a.i./A) 0.13 (USEPA, 2011, D394234, D394479) Maximum application rate Aerobic Aquatic Metabolism Half - life ( day s) Parent: 24 Parent+ Unextracted Residues: 99 MRID s 44988513, 49034201 The 90 th percentile upper

confidence bound on the mean of 3 values. T wo values were adjusted to 25 o C. Organic carbon normalized distribution coefficient (KOC ; mL/g OC) 227 MRID 44651884 Mean of five K OC values . Coefficients of variation (CV) were lower for KOC (CV=28%) as compared to Kd (CV=66%). **Table 9**  **. Tier I PRZM -**  **GW input parameters Param**  **eter (units) Residues**  **Input Value Data Source**  **Comments** Hydroly sis Half

life (days) Parent Stable (0) MRID 44651876 Hydroly sis half - life at pH 7 and 25 o C. Soil Metabolism Half - life at 25 o C (days) Parent 2.4 at 25 o C MRIDs 46867004, 44746001, 46386605 The 90 percent upper confidence

bound on the mean of 8 half - life values. Values were adjusted to 25 o C. Parent + unextracted residues 39 at 25 o C Koc (L/kg - OC) Parent 227 MRID 44651884 Mean of five K OC values.

Coefficients of variation (CV) were lower for KOC (CV=28%) as compared to Kd (CV=66%). 6.3 Modeling Results S urface water modeling results for acetamiprid plus unextracted residues are presented in **Table 10**  , with maximum values given in bold . Groundwater modeling results are presented in **Table 11**  . Output files from the model run associated with the maximum EDWCs for each model are provided in **Appendix B** . Output concentrations for surface water were not adjuste d using a PCA adjustment factor because acetamiprid is registered for use on a variety of landcover classes including residential, commercial, and agricultural areas and is applied to more than one crop . The national default PCA adjustment factor is 1.0. Model o utput concentrations for groundwater are not adjusted using a PCA , since PCAs represent watershed - scale dilution effects that cannot be presumed to apply to groundwater . **Table 10**  **. Estimated**  **c oncentrations of**  **acetamiprid and**  **u nextracted**  **r esidues in**  **s urface**  **w ater**  **s ource**  **d rinking**  **w ater**  **Use Pattern (Model) Application Scenario**  **EDWC μg/L Peak**  **Annual Average** Bait (FIRST) 0.082 lbs a.i./A (0.092 kg a.i./ha) , 24x, 3 day interval, ground **81.5** 5.88 * 14.6 0. 339 * Tree Nuts (FIRST) 0.18 lbs a.i./A (0.20 kg a.i./ha) , 4x, 14 day interval, air 38.8 7.11 Cranberries ( Provisional Cranberry Model ) 0.13 lbs a.i./A (0.15 kg a.i./ha), 2x, 7 day interval,

air 88.3 79.2* **32.2** 7.88* *Residues of Acetamiprid alon e , calculated for the scenarios that resulted in a high est EDWC s for surface water.

###  13

 1 EDWC s are shown for residues of acetamiprid plus unextracted residues, as suming an aerobic soil metaboli s m input of 39 days and an aerobic aquatic metabolism half - life of 99 days , unless otherwise indicated with an asterisk . Values with an asterisk are results for residues of acetamiprid alone, assuming an aerobic soil metabolism half - life of 2.4 days and an aerobic aquatic metabolism half - life of 24 days. **Table 11**  **. Estimated**  **c oncentrations of**  **a cet**  **amiprid and u**  **nextracted r**  **esidues in**  **g roundwater**  **s ource**  **d rinking**  **w ater**  **1 Use Site**  **Application**

**Scenario EDWC in μg/L** 

**SCI**   ** GROW** **PRZ M**  **- GW**  **Peak Scenario**  **Daily Peak**  **Post Breakthrough**  **Average Average** 

**Breakthrough Time (Days)**  Bait 0.082 lbs a.i./A

(0.092 kg a.i./ha), 24x, 3 day interval, ground 0.019 WI **49.7** 0.03* **45**

0.01* 5411 Tree Nut 0.18 lbs a.i./A (0.20

kg a.i./ha), 4x, 14 day interval, air 0.013 WI 18.8 16.8 5411 Abbreviations: WI=Wisconsin Corn Bold values show

the highest EDWC from groundwater source drinking water. *Residues of Acetamiprid alon e 1 EDWC s are shown for residues of acetamiprid plus unextracted residues, assuming an aerobic soil metabolism input of 39 days, unless otherwise indicated with an asterisk . Values with an asterisk are results for residues of acetamiprid alone, assuming an aerobic soil metabolism half - life of 2.4 days. The Wisconsin sands scenario resulted in the highest EDWCs across PRZM - GW scenarios. 

### 7 **MONITORING DATA** The following databases and sources were searched for monitoring information on acetamiprid:

 Water Quality Portal (http://www.waterqualitydata.us/portal.jsp )  California Environmental Data Exchange Network ( http://ceden.waterboards.ca.gov/AdvancedQueryTool ) No monitoring information was found. 

### 8 **DRINKING WATER TREATMENT EFFECTS** There is no available information on the effects of drinking water treatment on acetamiprid. The EDWCs in this assessment are representative of concentrations in drinking water source water (pre - treatment). For surface water, the conceptual model assumes that a pesticide reaches surface water via spray drift or surface runoff and it is instantaneously mixed and concentrations are observed in the water body. Acetamiprid is stable to hydrolysis. Therefore, acetamiprid will not degrade by hydrolysis during the time th at elapses from drinking water intake through distribution to the first tap. Photolysis is a relatively unimportant degradation pathway. Therefore, if ultraviolet light were used as a means of disinfection, degradation of acetamiprid would not be expec ted to be significant. Acetamiprid does degrade via aerobic metabolism in soil and sediment and some may degrade in an aerobic digester where aerobic metabolism occurs . However, the half - life is much longer than the residence time of the water within a typical treatment plant. The most successful drinking water treatment process for removal of

###  14



pesticides from drinking water is thought to be treatment with granular activated carbon (GAC) which is only used in larger drinking water treatment facilities. T he ability of GAC to remove pesticides will vary with the properties of the chemical and whether the sorption sites on GAC have reached capacity (Badriyha et al. , 2003; Zhao et al. , 1999) . Data on the sorption of acetamiprid to GAC are not available; however, a high percentage of sorption and thus removal of acetamiprid to GAC is likely to occur, as acetochlor (reported KOC of 156 L/kg) was removed from river water treated with GAC (AERU, 2009; Badriyha et al. , 2003) . **9 UNCERTAINTIES AND**  **DATA GAPS** The estimated concentrations provided in this assessment were generated from Tier 1 models and are conservative estimates of acetamiprid concentrations in untreated drinking water. There were a number of uncertainties associated with this drinking water exposure assessment. The major uncertainty what the maximum number of applications would be for the scatter bait use. Another source of uncertainty in the assessment is the inclusion of unidentified, unextracted residues in the calculation of aerobic soil and aerobic aquatic metabolism half - lives. For the scenarios resulting in the highest surface water EDWC s , inclusion of unextracted residues in half - life calculations resulted in EDWCs that are 14 to 43 times EDWCs based on parent alone . Ther efore, the identity of the unextracted residues results in a significant uncertainty in the risk assessment. The drinking water assessment is a screening - level assessment based upon standard models and assumptions. The modeling assessment relies on a maximum use pattern ( maximum label application rate s ) to reflect surface water and groundwater concentrations, and a national PCA of 1.0 to reflect potential surface water concentrations. To the extent that actual use patterns involve application of less a.i. than the permissible on the label , and location - specific crop acreages represent lower land coverage percentages than the national maximum PCA used in this assessment, aquatic concentrations (particularly the acute) in some locations will be lower tha n EDWCs reported herein. There is also uncertainty associated with modeling with FIRST, SCI - GROW, PRZM - GW, and the Provisional Cranberry Model. They are all Tier I models or were run with Tier I assumptions and therefore could potentially overestimate chemical concentrations. If dietary risks require refinement, higher tiered models and modeling scenarios can be utilized upon request. Itis noted that as a groundwater screening tool, PRZM - GW in general works to simulate concentrations greater than tho se that are likely to be present in the vast majority of drinking water supplies . PRZM - GW does not consider erosion or runoff of a pesticide, which may make a compound less available for leaching to groundwater. The Provisional Cranberry Model, estimates concentrations in the cranberry bog, assuming the bog is flooded for the entire year. Cranberry bogs are not flooded the entire year, and it is understood that dilution of water would occur before it would move to where drinking water intakes were locate d. Therefore, the Provisional Cranberry Model will likely overestimate EDWC s . **10 REFERENCES**  10.1 Literature Cited AERU. 2009. The FOOTPRINT Pesticide Properties Database. Agriculture & Environment Research Unit (AERU). Available at http://sitem.herts.ac.uk/aeru/footprint/ (Accessed July 9, 2009). Badriyha, B. N., Ravindran, V., Den, W., & Pirbazari, M. 2003. Bioadsorber efficiency, design, and performance forecasting for alachlor removal. Water Research, 37 . Burns, L. A. 2000. Exposure Analysis Modeling System (EXAMS): User Manual and System Documentation. Revision G . EPA/600/R- 00/81 - 023. September 2000. Ecosystems Research

###  15



Division. National Exposure Research Laboratory. United States Environmental Protection Agency. Cape Cod Cranberry Growers Association. 2001. Conservation District Grant Program of the Commonwealth of Massachusetts Executive Office of Environmental Affairs. Cranberry Water Use. An Information Fact Shee t . June 2001. Available at http://www.cranberries.org/pdf/wateruse.pdf (Accessed October 25, 2012). Carsel, R. F., Imhoff, J. C., Hummel, P. R., Cheplick, J. M., & Donigian Jr., J. S. 1997. PRZM - 3, A Model for Predicting Pesticide and Nitrogen Fate in Crop Root and Unsaturated Soil Zones: Users Manual for Release 3.0 . Memorandum From to Environmental Research Laboratory. Office of Research and Development. United States Environmental Protection Agency. USEPA. 2001. Acetamiprid. Results of the HED Metabolism Assessment Review Committee . D278652. Memorandum From H. Bietlot, M. Doherty & P. Hurley to Y. Donovan. Office of Prevention, Pesticides, ans Toxic Substances. United States Environment al Protection Agency. CFR. Part 2002. Acetamiprid Pesticide Fact Sheet . Government Printing Office. Washington, D.C. USEPA. 2009a. Estimation Program Interface (EPI) Suite: United States Environmental Protection Agency. Available at http://www.epa.gov/oppt/exposure/pubs/episuite.htm (Accessed July 9, 2009). USEPA. 2009b. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version 2.1 . Environmental Fate and Effects Division. Office of Pesticide Programs. U.S. Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/mo dels/water/input_parameter_guidance.htm (Accessed June 22, 2014). USEPA. 2010a. Guidance for Reporting on the Environmental Fate and Transport of the Stressors of Concern in the Problem Formulation for Registration Review, Registration Review Risk Assessme nts, Listed Species Litigation Assessments, New Chemical Risk Assessments, and Other Relevant Risk Assessments , January 25, 2010 . USEPA. 2010b. Guidance on Development and Use of Percent Cropped Area Adjustment Factors in Drinking Water Exposure Assessme nts . September 9, 2010. Environmental Fate and Effects Division, Office of Pesticide Programs, U.S. Environmental Protection Agency. Available at http://www.epa.gov/pesticides/science/efed/models/water/archives/pca_adjustment_dwa_9sep201 0.html (Accessed March 13, 2015). USEPA. 2010c. Guidance on Development and Use of the Index Reservoir in Drinking Water Exposure Assessments . September 14, 20 10. Environmental Fate and Effects Division. Office of Pesticide Programs. U.S. Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/index_ reservoir_dwa.pdf (Accessed December 9, 2010). USEPA. 2010d. WQTT Advisory Note Number 9: Temperature Adjustments for Aquatic Metabolism Inputs to EXAMs and PE5 . Memorandum From D. F. Young to Water Quality Tech Team. September 21, 2010. Environmental Fa te and Effects Division. Office of Chemical Safety and Pollution Prevention. U.S. Environmental Protection Agency. Available at http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/water_quality_tech_te am/wqtt_temp_adjust_exams_pe5.htm (Accessed March 13, 2015). USEPA. 2011.D390070. Tier I Drinking Water Exposure Assessment for the Section 3 New Use of Acetamiprid on Soybeans to Control a Variety of Insect Pests . D390070. Memorandum From K. White to M. Doherty, C. Swartz & J. Urbanski. July 21, 2011. Environmental Fate and Effects Division. Office of Chemical Safety and Pollution Prevention. United States Environmental Protection Agency. USEPA. 2011.D394234, D394479. Tier I Drinking Water Exposure Assessment for the Section 3 New Use of Acetamiprid on Various Agricultural Crops and as a Scatter Bait to Control Insects. D394234 & D394479. October 11, 2011. Environmental Fate and Effects Division. Office of

###  16



Pesticide Programs. United States Environmental Protection Agency. USEPA. 2012.D391431. Fenpyroximate: Drinking Water Exposure Assessment for Proposed New Uses on Snap Beans and Tropi cal Fruits including Avocado and a Proposed Outdoor Use on Cucumbers . D391431. Memorandum From G. Orrick to G. Kramer & S. Jackson. Environmental Fate and Effects Division. Office of Pesticide Programs. United States Environmental Protection Agency. U SEPA. 2012.DP Barcode 401171. Registration Review- Preliminary Problem Formulation for Ecological Risk and Environmental Fate, Endangered Species, and Drinking Water Assessments for Acetamiprid. D401171. Environmental Fate and Effects Division. Office o f Pesticide Programs. United States Environmental Protection Agency. USEPA. 2012. Standard Operating Procedure for Using the NAFTA Guidance to Calculate Representative Half

- life Values and Characterizing Pesticide Degradation . November 30, 2012. Environmental Fate and Effects Division. Office of Pesticide Programs. U.S. Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/ec orisk_ders/degradation_kinetics/NAFTA_Degradation_Kinetics. htm (Accessed December 16, 2013). USEPA. 2012.D405064. Tier I Drinking Water Exposure Assessment for the Section 3 New Use of Boscalid on Various Agricultural Crops Including Cranberries . D405064. Memorandum From K. White to S. Funk, B. O'Keefe, A. Ertman & B. Madden. November 27, 2012. Environmental Fate and Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Prevention. U.S. Environmental Protection Agency. USEPA. 2013a. Guidance for Using PRZM - GW in Drinking Water Exposure Assessments . December 11, 2012. Environmental Fate and Effects Division. Office of Pesticide Programs. U.S. Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_guidance.htm (Accessed January 22, 2013). USEPA. 2013b. Guidance on Modeling Offsite Deposition of Pesticides Via Spray Drift for Ec ological and Drinking Water Assessment . Environmental Fate and Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Prevention. U.S. Environmental Protection Agency. Available at http://www.regulations.gov/#!docketDetail;D=EPA - HQ - OPP - 2013 - 0676 (Accessed April 11, 2014). USEPA. 2014a. Development of Community Water System Drinking Water Intake Percent Cropped Area Adjustment Factors for use in Drinking Water Exposure Assessments: 2014 Update . September 9, 2104. Environmental Fate and Effects Division. Office of Pesticide Programs. U.S. Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/ (Accessed March 9, 2015). USEPA. 2014b. Development of Community Water System Drinking Water Intake Percent Cropped Area Adjustment Factors for use in Drinking Water Exposure Assessments: 2014 Update . 9/9/14. Environmental Fate and Effects Division. Office of Chemical Safety and Pollution Prevention. U.S. Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/Development_and_Use_of_Community_Water_Syst em.pdf (Accessed February 9, 2014). USEPA. 2014c. Guidance for Addressing Unextracted Residues in Laboratory Studies . Memorandum From to E. F. a. E. Division. September 12, 2014. Environmental Fate and Effects Division. Office of Pesticide Programs. Office of Chemical Safety and Pollution Prevention. Available at http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/environmental_fate_te ch_team/Unextracted_Residues_in_Lab_Studies.htm (Accessed March 13, 2015). USEPA, & Health Canada. 2013. Guidance for Selecting Input Parameters for Modeling Pesticide Concentrations in Groundwater Using the Pesticide Root Zone Model . Version 1. October 15, 2012. Environmental Fate and Effects Division. Office of Pesticide Programs. U.S.

###  17



Environmental Protection Agency. Available at http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_input_guidance.htm (Accessed February 28, 2013). USNLM. 2009. TOXNET Toxicology Data Network. United States National Library of Medicine (USNLM). Available at http://toxnet.nlm.nih.gov/ (Accessed July 9, 2009). Zhao, X., Hickey, R. F., & Voice, T. C. 1999. Long - term evaluation of adsorption capacity in a biological activated carbon fluidized bed reactor system. Water Research, 33 (13). 10.2 Submitted Studies **Solubility** 44651810 Gomyo , T.; Kobayashi, S. (1997) NI - 25 -- Solubility in Organic Solvents: Amended Final

Report: Lab Project Number: NISSO 2 - 83: EC - 376 - 3: 2 - 83. Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 32 p. 44651811 Gomyo , T.; Kobayashi, S. (1997) NI - 25 -- Solubility in Water: Amended Final Report: Lab

Project Number: NISSO 2 - 81: EC - 377 - 3: 2 - 81. Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 37 p. **Vapor Pressure** 44651812 Gomyo , T.; Kobayashi, S. (1997) NI - 25 -- Vapor Pressure: Amended Final Report: Lab Project

Number: NISSO 2 - 79: EC - 372 - 2: 2 - 79. Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 43 p. **Dissociation Constant** 44651813 Gomyo, T.; Kobayashi, S. (1997) NI - 25 -- Dissociation Constant in Water (pKa): Amended

Final Report: Lab Project Number: NISSO 2 - 88: EC - 371 - 2: 2 - 88. Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 30 p. **Oct/Water partition Coef.** 44651814 Gomyo, T.; Kobaya shi, S. (1997) NI - 25 -- Octanol/Water Partition Coefficient: Amended Final

Report: Lab Project Number: NISSO 2 - 84: EC - 378 - 2: 2 - 84. Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 34 p. **Hydrolysis** 44651876 Gomyo, T.; Kobayashi, S. ( 1997) NI - 25 -- Hydrolysis: Amended Final Report: Lab Project

Number: NISSO 2 - 89: EC - 375 - 2: 2 - 89. Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 126 p. 44651877 Class, T. (1997) Hydrolysis of IM - 1 - 4 and IC - 0 (Two Degradates of Acetamiprid) as a

Function of pH: Lab Project Number: P 225 G: B 225 G: 97 - 32. Unpublished study prepared by PTRL Europe. 24 p. **Photodegradation -** **water** 44988509 Hausmann, S.; Class, T. (19 98) Aqueous Photodegradation of (carbon - 14) -Acetamiprid at pH

7 and Determination of Quantum Yield: Lab Project Number: P196G: B196G: 96 - 82. Unpublished study prepared by PTRL, West PTRL, Europe. 124 p.

###  18



44988510 Emeric, G. (1998) Acetamiprid -- Verificatio n of the Identity of the Photolyte Obtained at pH

7 -- Study: Lab Project Number: 98 - 47. Unpublished study prepared by Rhone - Poulenc Agro. 36 p. 44988511 Mamouni, A. (1997) Aqueous Photolysis of (carbon - 14) - IM - 1 - 4 Under Laboratory

Conditions: Lab Project Number: 671332: 97 - 166. Unpublished study prepared by RCC Um weltchemie. 64 p. **Photodegradation -**  **soil** 44988508 Mislankar, S. (1998) Acetamiprid (NI - 25) Soil Photolysis: Lab Project Number: EC - 97 - 359:

F97125 - 806: EC - 97 - 359 - HP. Unpublished study prepared by Rhone - Poulenc Ag Company. 149 p. **Aerobic soil metabolism** 44651879 Feung, C. (1998) Acetamiprid (NI - 25): Aerobic Soil Metabolism: Lab Project Number: EC 96 - 351. Unpublished study prepared by Rhone - Poulenc Ag Company. 122 p. 44651880 Feung , C. (1998) Acetamiprid (NI - 25): Metabolism in Collombey Soil: Lab Project Number:

EC - 97 - 406. Unpublished study prepared by Rhone - Poulenc Ag Company. 78 p. 44651881 Burr, C. (1997) (Carbon 14) -NI - 25: Rate of Aerobic Degradation in Three Soil Types at 20

(degrees Centigrade) and One Soil Type at 10 (degrees Centigrade): Lab Project Number: 11256: 201445. Unpublished study prepared by Rhone - Poulenc Agriculture Limited. 213 p. 44651882 Lowden, P.; Oddy, A.; Jones, M. (1997) NI - 25: Rate of Degradation of th e Acid Metabolite,

(carbon 14) - IC - O in Three Soils: Lab Project Number: 11257: 20147. Unpublished study prepared by Rhone - Poulenc Agriculture Limited. 153 p. 44699101 Morgenroth, U. (1997) (Carbon 14) -NI - 25: Metabolism in One Soil Incubated Under Aerobic

Conditions: Lab Project Number: 373994. Unpublished study prepared by RCC Um weltchemie AG. 125 p. **Anaerobic aquatic metab.** 44988512 Feung, C. (1999) Acetamiprid (NI - 25): Anaerobic Aquatic Metabolism: Lab Project Number:

EC - 97 - 404. Unpublished study prepared by Rhone - Poulenc Ag Co. 128 p. **Aerobic aquatic metab.** 44988513 Andrawes, N. (1999) Acetamiprid (NI - 25): Aerobic Aquatic Metabolism: Lab Project

Number: EC - 96 - 352. Unpublished study prepared by Rhone - Poulenc Ag Co. 143 p. 49034201 Degradation in Two Water/Sediment Systems. Unpublished study performed and sponsored

by Rhone - Poulenc Agriculture Limited, Essex, UK, and submitted by Nippon Soda Co., Ltd, Tokyo, Japan. Laboratory Project ID.: 11263. Experiment started June 28, 1996, and terminated March 14, 1997 (p. 49). Final report issued June 20, 1997. **Leach/adsorp/desorption** 44651883 Liu, A. (1997) Acetamiprid (NI - 25): Soil Adsorption/Desorption Study: Lab Project Number:

EC - 97 - 381: F97525 - 001: RP397ACL. Unpublished study prepared by Rhone - Poulenc Ag

###  19

 Company. 180 p. 44651884 Liu, A. (1997) 6 - Chloronicotinic Acid (Acetamiprid Metabolite): Soil Adsorption/Desorption

Study: Lab Project Number: EC - 97 - 370: F97525 - 001: RP397ACL. Unpublished study prepared by Rhone - Poulenc Ag Company. 195 p. 44651885 Liu, A. (1998) (Carbon 14) -N - methyl - (6 - chloro - 3 -pyridyl) - methylamine IM - 1 - 4

(Acetamiprid Metabolite): Soil Adsorption/Desorption Study: Lab Project Number: EC - 97 - 382: F97525 - 001: RP397ACL. Unpublished study prepared by Rhone - Poulenc Ag Company. 1 68 p. 44651886 Morgenroth, U. (1997) (Carbon 14) -NI - 25: Leaching Characteristics of Aged Residues in One

Soil: Lab Project Number: 374005. Unpublished study prepared by RCC Umweltchemie Ag. 95 p. 46255604 Simmonds, M. (2003) (Carbon 14) - Acetamiprid: Aged Residue Column Leaching Study in

Two Calcareous Soils. Project Number: CX/02/018, CX02018. Unpublished study prepared by Battelle Agrifood, Ltd. 159 p. **Terrestrial field dissipation** 44988514 Norris, F. (1999) Acetamiprid: Terrestrial Soil Dissipatio n of Acetamiprid Following

Applications of EXP 80667A 70WP to Ornamental Crops: Lab Project Number: 45752: 97512637. Unpublished study prepared by Rhone - Poulenc Ag Co. and Agvise, Inc. 798 p. 44988515 Norris, F. (1999) Acetamiprid: Terrestrial Soil Dissipation of Acetamiprid (EXP 80667A)

Under Agricultural Field Conditions Crops: Lab Project Number: 45753: 975126643: 12643 - 06. Unpublished study prepared by Rhone - Poulenc Ag Co. and ACDS Research, Inc. 788 p. 44988516 Yang, J. (1999) Method Validation Rep ort for Acetamiprid (NI - 25): Performance Summary of

Methods of Analysis for NI - 25 and its Metabolites IC - 0, IM - 1 - 4, and IM - 1 - 2 in US Soil Using LC/MS/MS: Lab Project Number: 45841: 45453: 9752643. Unpublished study prepared by Rhone - Poulenc Ag Co. 572 p. O PPTS 850.7100 44988517 Zheng, S. (1999) Independent Laboratory Validation of Analytical Methods NI - 25: Method of

Analysis and its Metabolite, IC - 0, Using LC/MS/MS; NI - 25: Methods of Analysis for IM - 1 - 2 a Metabolite of NI - 25 in Soil Using LC/MS/MS; and NI - 25: Method of Analysis f or IM - 1 - 4, a Metabolite of NI - 25, in Soil Using LC/MS/MS: Lab Project Number: 019 - 016: 98P - 019 - 016: EC - 98 - 447. Unpublished study prepared by Centre Analytical Labs., Inc. 152 p. OPPTS 850.7100 44988625 Cosgrove, D. (1999) A Terrestrial Field Dissipation Study with Acetamiprid, Canada, 1999:

Final Study Report: Lab Project Number: 99086DC: 99001: 99002. Unpublished study prepared by Enviro - Test Lab., Inc. 388 p. **Dissociation constants in water** 46255602 Takashima, K. (2002) Dissociation Constant of IM - 1 - 5. Project Number: NCAS/02/132.

Unpublished study prepared by Nisso Chemical Analysis Service Co., Ltd. 18 p. **Photodegradation of parent and degradates in soil** 48563501 Sugiyama, K. (2011) Photodegradation of [(Carbon 14)] Acetamiprid on Soil by Artific ial

###  20

 Sunlight. Project Number: 2126W. Unpublished study prepared by PTRL West, Inc. 235p. **Aerobic soil metabolism** 46255603 Simmonds, M. (2002) (Carbon 14) -Acetamiprid: Rate of Degradation in Three Calcareous

Soils at 20 (Degrees) C. Project Number: CX/01/013. Unpublished study prepared by Battelle Agrifood, Ltd. 198 p. **Anaerobic soil metabolism** 48554501 Hiler, T. (2011) (Ace tamiprid Technical): Anaerobic Soil Metabolism of Carbon 14

Acetamiprid on Two Soil Types. Project Number: 2105W, 2111W. Unpublished study prepared by PTRL West, Inc. 170p.

###  21

 **Appendix A**  **. Selected Modeling Output Files SELECTED SURFACE WATER MODELING OUTPUT FILES**  **FIRST Residues of Acetam** **iprid Plus**  **Unextracted Residues** RUN No. 1 FOR acetamiprid ON bait * INPUT VALUES *

-------------- ------------------------------------------------------ RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

------------------------------------------------------- ------------- 0.082( 1.140) 24 3 227.0 4250.0 GRANUL( 0.0) 100.0 0.0 FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES. - EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 39.00 2 0.00 34 .00 - 4216.00 99.00 96.73 UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008

-------------------------------------------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) CONCE NTRATION CONCENTRATION

--------------------------------------------------------------------

81.484 14.633 RUN No. 2 FOR acetamiprid ON treenuts * INPUT VALUES *

----------- --------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

---------------------------------------------------- ---------------- 0.180( 0.515) 4 14 227.0 4250.0 AERIAL(16.0) 100.0 0.0 FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES. - EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 39.00 2 N/A 34.00 - 4216.00 99.00 96.73 UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008

-------------------------------------------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

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38.782 7.107 **Residues of Acetam iprid Alone**  RUN No. 3 FOR acetamiprid ON bait * INPUT VALUES *

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

RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

-------------------------------------- ------------------------------ 0.082( 0.141) 24 3 227.0 4250.0 GRANUL( 0.0) 100.0 0.0 FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSI S PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES. - EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 2.40 2 N/A 34.00 - 4216.00 24.00 23.86 UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008

-------------------------------------------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

--------------------------------------------------------------------

5.881 0.339 .458

**GROUNDWATER MODELING OUTPUT FILES PRZ** **M -**  **GW Output**  **– Acetamiprid**  **Plus Unextracted Residu es**  **Groundwater Analysis for Acetam iprid**  **Plus Unextracted Residues and the Wisconsin Corn**  **- WI Central Sands Scenario**  

### Groundwater Analysis for acetamiprid plus unextracted residues for a scatter bait use using the **Wisconsin Corn -**  **WI Central Sands Scenario** Estimated groundwater concentrations and breakthrough times for acetamiprid scatter bait use are presented in Table 1 for the Wisconsin Corn - WICentral Sands groundwater scenario. A graphical presentation of the daily concentrations in the aquifer is presented in Figure 1. These values were generated with the PRZM - GW (Version 1.07). Critical input values for the model are summarized in Tables 2 and 3. **Table 1. Groundwater Results for Acetamiprid plus unextracted residues or descriptive information. and the Wisconsin Corn**  **- WI Central Sands Scenario.**  Peak Concentration (ppb) 49.7 Post - Breakthrough Mean Concentration (ppb) 45 Entire Simulation Mean Concentration (ppb) 25.8 Average Breakthrough Time (day s) 5411.183 Throughputs 2.025435 **Table 2. Chemical Properties for Groundwater Modeling of Acetamiprid plus unextracted residues or descriptive information..** 

###  23

 Koc (ml/g) 227 Surface Soil Half Life (day s) 39 Hydroly sis Half Life (day s) 0 Diffusion Coefficint Air (cm2/day) 0.0 Henry's Constant 0.0 Enthalpy (kcal/mol) 0.0 **Table 3. Pesticide application scheme used for Acetamiprid plus unextracted residues or descriptive information.. This application scheme was applied every year of the simulation.**  Application Days Relative to Emergence Date (05/01) Application Method Application Rate (kg/ha) 0 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 3 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 6 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 9 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 12 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 15 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 18 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 21 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 24 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 27 Ground application with mass distribution increasing proportionally with depth t o 4 cm 0.092 30 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 33 Ground application with mass distribution increasing proportionally with depth to 4 0.092

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 cm 36 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 39 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 42 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 45 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 48 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 51 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 54 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 57 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 60 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 63 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092 66 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.09 2 69 Ground application with mass distribution increasing proportionally with depth to 4 cm 0.092

###  25

 **Figure 1. Aquifer Breakthrough Curve for Acetamiprid plus unextracted residues or descriptive**  **information. and the Wisconsin Corn -**  **WI Central Sands Scenario**

**SciGrow version 2.3** Bait Use SciGrow version 2.3 chemical: acetamiprid time is 3/13/2015 13:56:26

------------------------------------------------------------ ------------ Application Number of Total Use Koc Soil Aerobic rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

------------------------------------------------------------------------ 0.082 24.0 1.968 2.51E+02 6.7

------------------------------------------------------------------------ groundwater screening cond (ppb) = 1.89E - 02 ****************************************************************** ******