UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 DP Barcodes: D311925, D311927, D311929, D311952, D318281, D318285, D318286, D318287, D321441, D321442, D321443, D321444, D321445, D321446, D321937, D321938, D321942, D321943, D323440, D325813. PC Code: 129099 MEMORANDUM May 17, 2006 SUBJECT: Drinking Water Assessment for Imidacloprid: IR 4 Registration of New Uses and Modified Application Rates TO: Jennifer R. Tyler RAB1/ HED ( 7509C)

FROM: Ronald D. Parker, Ph. D. Senior Environmental Engineer ERB5/ EFED ( 7507C)

THRU: Mah Shamim, Branch Chief ERB5/ EFED ( 7507C)

EXECUTIVE SUMMARY. This memo summarizes the Tier I estimated drinking water concentrations ( EDWCs) for new uses and for modified rates of application for Imidacloprid insecticide on several crops. These crops include cotton, tropical fruit ( including sugar apple, citrus, avocado), oilseeds crop group ( canola and rape), coffee, cranberry, blackberry, raspberry, juneberry, lingonberry, pome granate, tree nuts crop group 14 ( including pecan and pistachio), banana and plantain, herbs subgroup 19A, rye, oat, brassicas and leafy vegetables.

These surface water concentration values were calculated using the FQPA Index Reservoir Screening Tool ( FIRST) described below. New ground water concentration values were not estimated because they have been shown previously to be substantially lower in magnitude than the surface water concentrations. See Imidacloprid: Tier I Drinking Water EECs for Use in the Human Health Risk Assessment", February 25, 2003, from Michael Barrett ( EFED) to Jennifer Tyler ( HED) attached to this memo as Appendix B.

EDWCs for these new Imidacloprid uses do not exceed those for crops evaluated previously and therefore overall result of the exposure assessment is unchanged. For this reason, a tier II assessment with the PRZM and EXAMS models was not performed. The highest acute EDWC for the new crops is 35.9 ppb from usage on tree nuts. The previous highest acute value was 35.4 to 36.0 for usage on citrus. The highest chronic EDWC for the new crops is 15.3 ppb from usage on tree nuts and coffee. The previous highest chronic value was from 16.5 to 17.2 for usage on citrus. A summary of the model input parameter values used in FIRST is presented in Table 2. FIRST output files are attached in Table 3.

PROBLEM FORMULATION This is a Tier I drinking water assessment that uses modeling to estimate the groundwater and surface water concentrations in drinking water source ( pre treatment), resulting from pesticide use on sites that are highly vulnerable. This initial tier screens out chemicals with low potential risk and allows OPP to focus resources on more refined risk assessments for chemicals that potentially present more significant risks. This drinking water assessment will report potential exposure concentrations for the human health dietary risk assessment and provide a clear and transparent description of how those concentrations were determined.

ANALYSIS Environmental Fate Summary Imidacloprid is stable to hydrolysis, and typically persists for many months in soil. However, imidacloprid appears to be more rapidly transformed under anaerobic conditions and appears to be particularly photolabile in pure, clear shallow water. Given that imidacloprid is mobile, and likely to be highly persistent in the subsurface, it may leach to ground water ( results of the prospective ground water monitoring studies confirm this). Imidacloprid may also pose a contamination hazard to surface waters via runoff, and may be especially persistent in surface water with high turbidity.

The environmental fate for imidacloprid is as follows ( See Appendix D for further details):

Water solubility ( 200C) = 580 ppm Hydrolysis ( pH 5 and 7) = stable Hydrolysis ( pH 9) = 355 days Photolysis half life, distilled water = 0.2 days Photolysis half life, soil = 39 ( estimates from the single study range from 39 to 171 days) Aerobic soil metabolism half life = 359 ( 188 to 660 days, 4 soils including 1 in U. S.) Anaerobic Aquatic = 27 days Freundlich adsorption coefficient between 0.96 to 4.76 Soil leaching ( Koc) = 178 ( 132 to 256) ml/ g Field dissipation half life ( 0 to 3 inch depth) = 107 to >> 365 days ( 5 sites)

EFED concludes that the available data on imidacloprid show that the compound is mobile and persistent, has potential to leach to ground water, and also presents concerns for transport to surface water by runoff. No direct environmental fate studies have been conducted for the degradates { several of which retain the ( pyridinyl) methyl imidazoli amine backbone of the imidacloprid molecule}, including the following: 1) imidacloprid guanidine, 1[( 6 chloro 3 pyridinyl) methyl] 2 imidazolidinimine { Alias NTN 38014, NTN 33823}; 2) imidacloprid olefin, 1[( 6 chloro 3 pyridin1yl) methyl] 1,3 dihydro 2H imidazol 2 imine; and 3) imidacloprid urea, 1 [( 6 chloro 3 pyridinyl) methyl] 2 imidazolidinone.{ NTN 33519}. Please refer to the Table 2 for modeling input parameters. See Appendix C for chemical structures of these degradates.

Use Characterization Table 1 is a summary of all new agricultural use patterns for Imidacloprid. The use information was obtained from the current labels for products containing Imidacloprid.

Table 1. Imidacloprid Uses and FIRST Drinking Water Exposure Summary Name / Formulation Crops Treated Appl. Methods Max Appl Rates (# a. i. / ac) App/ year Min. Appl Inter 1/ 10 Peak ( ppb) 1/ 10 Ann. ( ppb) ENCORE Imidacloprid 40.7% Cotton Aerial/ Ground Spray 0.31 / year 0.062/ appl 5 7 4.95 2.81 PROVADO Solupak 75% Cotton Aerial/ Ground foliar spray 0.31 / year 0.062/ appl 0.50 / year 5 7 4.95 2.81 PROVADO 1.6 Flowable Insecticide 17.4% Cotton Aerial/ Ground Foliar spray 0.31 / year 0.062/ appl 0.50 / year: Pear, citrus Bushberry Poplar, Cottonwd 5 7 4.95 2.81 PROVADO 70 WG Insecticide 17.4% Cotton Aerial/ Ground Foliar spray 0.31 / year 0.062/ appl 0.5 / year: Artichoke, Pear, citrus Bushberry Poplar, Cottonwd 5 7 4.95 2.81 PROVADO Solupak 75% Tropical Fruit ( Sugar apple Citrus Avocado) Aerial/ Ground Foliar spray 0.5 / year 0.1 / app 5 10 34.20 14.26 PROVADO 1.6 Flowable Sugar apple Ground 0.5 / year 0.1 / appl 5 7 34.47 15.04 GAUCHO Oilseeds slurry mix 32 fl oz. 1 N/ A 5.50 2.38 Name / Formulation Crops Treated Appl. Methods Max Appl Rates (# a. i. / ac) App/ year Min. Appl Inter 1/ 10 Peak ( ppb) 1/ 10 Ann. ( ppb) 480 Flowable ( 40.7%) Crop group ( Canola / Rape) ( 0.25 gal) per CWT of seed: .08# a. i./ ac GAUCHO 480 Flowable ( 40.7%) and GAUCHO 600 Flowable ( 48.7%) Oilseeds Crop group: ( Canola / Rape) slurry mix 25.6 fl oz. ( 0.20 gal) per CWT of seed:

.08 lbs a. i./ ac 1 N/ A 5.50 2.38 PROVADO 1.6 Flowable Coffee ( Not CA) Aerial/ Ground 0.5 / year 0.1 / appl 5 7 34.74 15.31 ADMIRE 2 Flowable Coffee Chemig. into root zone drip 0.5 / year 0.25 0.5/ applic 1 N/ A 17.18 7.45 PROVADO 1.6 Flowable Coffee ( IR 4) Aerial/ Ground 0.5 / year 0.1 / appl 5 7 34.74 15.31 GAUCHO 550 SC Cranberry Blackberry Raspberry Chemig, Drip, Trickle 0.5 / year 1 N/ A 17.81 7.45 GAUCHO 600 SC Cranberry Blackbrry Raspberry Chemig, Drip, Trickle 0.5 / year 1 N/ A 17.81 7.45 ADMIRE 2 Flowable Caneberry blackberry Raspberry, Juneberry, Lingonbry Soil Inject. or Drip 0.5 / year 1 N/ A 17.81 7.45 ADMIRE 2 Flowable, PROVADO 1.6 Flowable, PROVADO 70 WG GAUCHO 550 SC GAUCHO 600 SC Pomegranate 0.50 / year 0.50 / appl ADMIRE 0.30 / year 0.10 / appl PROVAD O 1.6 1 3 N/ A 7 17.18 21.03 7.45 9.27 Name / Formulation Crops Treated Appl. Methods Max Appl Rates (# a. i. / ac) App/ year Min. Appl Inter 1/ 10 Peak ( ppb) 1/ 10 Ann. ( ppb) ADMIRE 2 Flowable, PROVADO 1.6 Flowable Tree Nuts including pecan, and pistachio 0.50 / year ( ADMIRE 0.36 / year 0.09 / app PROV 1.6 1 4 N/ A 6 35.09 24.97 15.31 10.89 ADMIRE 2 Flowable, Banana and Plantains Chemig. 0.5 / year N/ A 17.18 7.45 PROVADO 1.6 Flowable Banana and Plantains Broadc/ directed spray 0.1 / year 5 14 33.85 14.77 PROVADO 70 WG Banana and Plantains Broadc/ dire cted spray 0.1 / year 5 14 33.85 14.77 GAUCHO 550 17.18 17.18 7.45 GAUCHO 600 Banana and Plantains Chemig. similar to ADMIRE 0.5 / year 0.5 / year 1 1 N/ A N/ A 7.45 ADMIRE 2 Flowable Infurrow Spray directed on or below seed or chemig. 0.38 / year 1 N/ A 13.76 6.04 PROVADO 1.6 Flowable Herbs Subgroup 19A Aerial and/ or Ground 0.13 / year 3 5 14.03 6.16 PROVADO 70 WG Herbs Subgroup 19A Aerial and/ or Ground appl 0.13 / year 3 5 14.03 6.16 Rye and Oat Seed Treat. 0.125 / treatment 1 N/ A 8.59 3.72 Brassica & Leafy Veg. Aerial/ Ground 0.08 / appl 3 5 16.87 7.43 Table 2. FIRST Input Parameters for Imidacloprid New Uses. Parameter Input Source Solubility ( ppm) 580 Product chemistry submissions Hydrolysis t1/ 2 @ pH 7 ( days) Stable MRID 42055337 Aerobic soil t1/ 2 ( days) 520 MRIDs 452393 01, 02, 42073501; 90% upper bound confidence limit of mean Aerobic aquatic t1/ 2 ( days) 1040 2x the aerobic soil input value, per EFED guidance document Photolysis t1/ 2 in water ( days) 39 Input guidance & MRIDs 42256376; 42256377 Organic carbon partition coefficient  Koc ( mL/ g) 178 MRIDs 425208 01 and 420553 38 Application rates ( lb a. i./ Acre) 0.5 Label maximum rate for Tree Nuts ( Crop Group 14)

Applications / year 1 Label maximum rate for Tree Nuts ( Crop Group 14)

Application spacing N/ A Label maximum rate for Tree Nuts ( Crop Group 14)

Background Information on FIRST:

FIRST is a new screening model designed to estimate the pesticide concentrations found in water for use in drinking water assessments. It provides high end values on the concentrations that might be found in a small drinking water reservoir due to the use of pesticide. Like GENEEC, the model previously used for Tier I screening level, FIRST is a single event model ( one run off event), but can account for spray drift from multiple applications. FIRST uses a Drinking Water Reservoir instead of a pond as the standard scenario. The FIRST scenario includes a 427 acres field immediately adjacent to a 13 acres reservoir, 9 feet deep, with continuous flow ( two turnovers per year). The pond receives a spray drift event from each application plus one runoff event. The runoff event moves a maximum of 8% of the applied pesticide into the pond. This amount can be reduced due to degradation on field and the effect of binding to soil. Spray drift is equal to 6.4% of the applied concentration from the ground spray application and 16% for aerial applications.

FIRST also makes adjustments for the percent crop area. While FIRST assumes that the entire watershed would not be treated, the use of a PCA is still a screen because it represents the highest percentage of crop cover of any large watershed in the US, and it assumes that the entire crop is being treated. Various other conservative assumptions of FIRST include the use of a small drinking water reservoir surrounded by a runoff prone watershed, the use of the maximum use rate, no buffer zone, and a single large rainfall.

Table 3. Imidacloprid FIRST Output Files RUN No. 1 FOR Imidacloprid ON Herbs * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .380( .380) 1 1 178.0 580.0 GROUND( 6.4) 87.0 2.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  13.756 6.039 RUN No. 2 FOR Imidacloprid ON Coffee * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .100( .491) 5 7 178.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  34.740 15.308 RUN No. 3 FOR Imidacloprid ON Oil Seed * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .080( .080) 1 1 178.0 580.0 GRANUL( .0) 87.0 1.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  5.498 2.383 RUN No. 4 FOR Imidacloprid ON AugarApple * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .100( .487) 5 10 178.0 580.0 GROUND( 6.4) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  34.203 14.925 RUN No. 5 FOR Imidacloprid ON Cotton * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .062( .304) 5 7 178.0 580.0 AERIAL( 16.0) 20.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  4.951 2.182 RUN No. 6 FOR Imidacloprid ON Caneberry * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .500( .500) 1 1 178.0 580.0 GRANUL( .0) 87.0 2.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  17.181 7.447 RUN No. 7 FOR Imidacloprid ON Herb2 * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .130( .387) 3 5 178.0 580.0 GROUND( 6.4) 87.0 2.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  14.027 6.158 RUN No. 8 FOR Imidacloprid ON SugarApple * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .100( .491) 5 7 178.0 580.0 GROUND( 6.4) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  34.472 15.042 RUN No. 9 FOR Imidacloprid ON TreeNuts * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .500( .500) 1 1 178.0 580.0 ABLAST( 6.3) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  35.093 15.311 RUN No. 10 FOR Imidacloprid ON Pomegranate * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .500( .500) 1 1 178.0 580.0 GRANUL( .0) 87.0 2.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  17.181 7.447 RUN No. 11 FOR Imidacloprid ON Pomegranate * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .100( .297) 3 7 178.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  21.032 9.267 RUN No. 12 FOR Imidacloprid ON LeafyVeg * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .800( 2.384) 3 5 178.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  168.692 74.328 RUN No. 13 FOR Imidacloprid ON Banana * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .500( .500) 1 1 178.0 580.0 GRANUL( .0) 87.0 2.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)

 520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  17.181 7.447 RUN No. 14 FOR Imidacloprid ON Banana * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .100( .482) 5 14 178.0 580.0 GROUND( 6.4) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  33.851 14.771 RUN No. 15 FOR Imidacloprid ON Rye Seed * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .125( .125) 1 1 178.0 580.0 GRANUL( .0) 87.0 1.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  8.591 3.724 RUN No. 16 FOR Imidacloprid ON TreeNuts * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .090( .356) 4 6 178.0 580.0 ABLAST( 6.3) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  24.970 10.894 RUN No. 17 FOR Imidacloprid ON Coffee * INPUT VALUES *  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .500( .500) 1 1 178.0 580.0 GRANUL( .0) 87.0 2.0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  520.00 2 N/ A 39.00 4836.00 ****** 855.93 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.1.0 DEC 12, 2005  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  17.181 7.447 Appendix B. February 2003 Imidacloprid Drinking Water Assessment UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C. 20460 OFFICE OF PREVENTION, PESTICIDES, AND TOXIC SUBSTANCES PC Code: 129099 DP BARCODES: D271770, D271825, D278761, D285742, D286723, D285499 MEMORANDUM February 25, 2003 SUBJECT: Imidacloprid: Tier I Drinking Water EECs for Use in the Human Health Risk Assessment.

TO: Jennifer R. Tyler RAB1/ HED ( 7509C)

FROM: Michael R. Barrett, Ph. D. Chemist ERB5/ EFED ( 7507C)

THRU: Mah Shamim, Branch Chief ERB5/ EFED ( 7507C)

This memo summarizes the Tier I estimated environmental concentrations ( EECs) for imidacloprid total residues in surface water and in ground water for use in the human health risk assessments. The EECs are summarized in Table 1 ( Tier 1 EECs for parent imidacloprid alone are also provided for comparison). EFED used the simulation model FIRST to calculate the surface water EECs and used the regression model SCI GROW to calculate the ground water EEC. Insufficient ground and surface water monitoring data are available to fully assess exposure from monitoring data. Modeling output and chemical structures of imidacloprid and its degradates are provided in Attachments 1 and 2, respectively.

For the surface water and ground water assessments the citrus use was modeled, which has the highest overall seasonal application rate ( modeled as two applications of 0.25 lb ai/ A at a 14 day interval, this gives the highest EECs for any use with the tier I models). A summary of the model input parameter values used in FIRST is presented in Table 2. A summary of the model input parameter values used in SCI GROW is presented in Table 3.

Updated modeling was performed using the FIRST model ( previous modeling was performed with GENEEC, which has been replaced with FIRST for drinking water exposure 15 assessments by EFED). In the absence of definitive data on the persistence and mobility of the important degradates ( imidacloprid urea, imidacloprid guanidine, and imidacloprid olefin) the total residues were modeled using tentatively identified total residue data from aerobic soil metabolism studies and then assuming that the partitioning of all residues was at the same degree as imidacloprid parent. Each of these assumptions is conservative in terms of tending to result in overestimate of exposure except for with respect to the partioning of imidacloprid urea, which, from published studies, appears to be more mobile than the parent compound. A tendency to underestimate imidacloprid urea with this procedure should not significantly affect the total residue Estimated Environmental Concentration ( EEC) calculations in this review because the extent of formation of imidacloprid urea in soil metabolism studies was small and the levels of the urea degradate found to leach in field studies were also small.

Background on Imidacloprid Total Residue Modeling Inputs. For inputs related to persistence of imidacloprid total residues, the sum of all compounds of interest was subject to first order regression modeling in the same fashion as is typically done for parent compounds alone in EFED. In some cases the registrant did not unambiguously identify the residues chromatographed from soil extracts, in these cases, the peaks containing the degradates were summed with the realization that some of the peaks could, in addition to the compounds of interest, contain some amount of degradates other than imidacloprid urea, imidacloprid olefin, or imidacloprid guanidine.

Information on imidacloprid degradate soil mobility is found in both guideline studies submitted and the published literature. One study on soil adsorption / desorption for the imidacloprid guanidine degradate has been received from the registrant ( MRID 42520802); Koc values ranged from 327 to 942 g/ ml in five soils indicating significantly less mobility than for imidacloprid parent. In published studies ( not officially submitted to EPA) investigators found that the relative mobility of imidacloprid and certain degradates was imid. urea > imidacloprid > imid. olefin >= imid. guanidine1 2 Separate studies with the degradates on persistence and mobility ( especially from aerobic soil metabolism and batch equilibrium adsorption / desorption studies) submitted to OPP under Subdivision N ( Environmental Fate study) guidelines would be needed to more accurately model the total residues, especially should higher tier assessments be needed in 1 Oliviera, R. S., W. C. Koskinen, N. R. Werdin, and P. Y. Yen. 2000. Sorption of imidacloprid and its metabolites on tropical soils. J. Environ. Sci. Health. B35: 39 49.

2 Cox, L., W. C. Koskinen, and P. Y. Yen. 1997. Sorption desorption of imidacloprid and its metabolites in soils. J. Agric. Food Chem. 45: 1468 1472. 16 the future. The current assessment is sufficiently conservative for a Tier 1 assessment since the assumptions for the parent alone already estimate near maximum surface water exposure ( as demonstrated by the small differences in the exposure levels between the parent only and total residue EECs in Table 1). The very high persistence of imidacloprid in the environment is the primary reason that only a small increase in EECs results from adding degradates in this Tier 1 assessment.

Table 1. Estimated Tier 1 concentrations of imidacloprid in drinking water.

Surface Water ( ug/ L) Groundwater ( ug/ L) Chemical Acute Chronic Acute and Chronic Imidacloprid parent 35.28 to 35.89 2.18 to 16.52 1.43 Imidacloprid total residues 35.42 to 36.04 2.20 to 17.24 2.09 Table 2. FIRST input parameters ( pesticide specific) for imidacloprid total residues: citrus modeling scenario.

Parameter Input Source Solubility ( ppm) 580 Product chemistry submissions.

Hydrolysis Half Life ( pH 7) ( days) 0 MRID 42055337 Aerobic soil t1/ 2 ( days) 1016 MRIDs 452393 01, 02, 42073501; 90% upper bound confidence limit of mean Aerobic aquatic t1/ 2 ( days) 2031 2x the aerobic soil input value, per EFED guidance document Photolysis t1/ 2 in water ( days) 0.2 to 391 Input guidance & MRIDs 42256376; 42256377 Organic carbon partition coefficient  Koc ( mL/ g) 162 MRIDs 425208 01 and 420553 38 Application rate ( lb a. i./ Acre) 0.25 Label  max. rate for citrus ( foliar application)

# applications/ year 2 Label maximum for citrus Table 3. SCI GROW input parameters for Imidacloprid.

Parameter Input Source Aerobic soil metabolism t1/ 2 ( days) 483 MRIDs 452393 01, 02, & 03; 42073501; mean value 17 Koc ( mL/ g) 172 MRIDs 425208 01 and 420553 38 Application rate ( lb a. i./ Acre) 0.5 Label  max. rate for citrus Review of Degradate Monitoring Data: Degradate exposure was assessed both through monitoring data ( for ground water sources only) and modeling ( both ground and surface water). In ground water sampled from two small scale Prospective Ground Water ( PGW) Monitoring study sites, the degradates imidacloprid urea, imidacloprid guanidine, and imidacloprid guanidine olefin were all a very minor component of the detected residues. However, it is important to understand that total residues detected were almost always less than 0.5 ppb ( ug/ L) and usually less than 0.1 ppb whereas the minimum detection limit for imidacloprid and each of its degradates was 0.03 ppb. The implication of this is that theoretically, degradation products, if they were present at slightly less than 0.03 ppb would be the dominant residues present in many samples.

At the Michigan study site, imidacloprid urea was the most commonly detected degradate in soil pore water, but generally much less frequently than parent imidacloprid ( Table 2). In ground water imidacloprid parent was consistently detected in one of six monitoring well clusters in the treated field beginning about 500 days after application and continuing through the close of the study some 5 years after application. No degradation products were detected in ground water during this period ( there were a very few detections before application that may have been due to previous uses nearby or sample contamination). The maximum concentration of imidacloprid parent detected in ground water in any one sample at the Michigan study site was 0.24 ppb.

Table 4. Percentage of quantified residues present as degradation products at representative days after imidacloprid treatment in soil pore water at a 9 foot depth: Prospective ground water monitoring study in Montcalm County, Michigan ( 1996 to 2001).

Days after Treatment Lys. ID 446 747 1126 1605 L1 nd 0.0% 21.4% 0.0% L2 nd 0.0% 0.0% 0.0% L3 0.0% 0.0% 0.0% 0.0% L4 nd nd nd nd L5 nd nd 0.0% 0.0% L6 nd 0.0% nd nd 18 A second PGW study was conducted in Monterrey County, California. This study is inadequate to fully address the leaching potential of imidacloprid because very little ground water recharge occurring during the course of the study as evidenced by the almost complete lack of detection of the bromide tracer ( applied concurrently with imidacloprid) in ground water. The limited number of detections in soil pore water and ground water indicated that imidacloprid urea may contribute to the total residue that leached at the California site. No imidacloprid guanidine or imidacloprid olefin was found in any groundwater sample. Imidacloprid urea was detected in seven groundwater samples at a maximum concentration of 0.05 ppb ( just over the method detection limit of 0.04 ppb). The maximum combined imidacloprid, imidacloprid guanidine, imidacloprid olefin, and imidacloprid urea residue found in the suction lysimeters was 0.62 ppb at 633 days post application. The maximum combined imidacloprid residue in the ground water at the California site was 0.14 ppb found 149 days post application.

Important input parameter used in running the FIRST and SCI GROW models are provided in Tables 3 and 4. Modeling output and chemical structures of imidacloprid and its degradates are provided in Attachments 1 and 2, respectively.

ATTACHMENT 1: FIRST Files RUN No. 1 FOR Imidacloprid Total Residues ON Citrus * INPUT VALUES * Long photolysis half life ( 39 days)  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .250( .498) 2 14 161.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  1016.00 2 N/ A 39.00 4836.00 ****** 1430.31 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.0 AUG 1, 2001  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  36.040 17.243 RUN No. 2 FOR Imidacloprid Parent ON Citrus * INPUT VALUES * Long photolysis half life ( 39 days)  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .250( .496) 2 14 161.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS) 19  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  602.00 2 N/ A 39.00 4836.00 ****** 963.36 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.0 AUG 1, 2001  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  35.894 16.518 RUN No. 3 FOR Imidacloprid Total Residues ON Citrus INPUT VALUES * Short photolysis half life ( 0.2 days)  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .250( .498) 2 14 161.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  1016.00 2 N/ A .20 24.80 ****** 24.50 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.0 AUG 1, 2001  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  35.419 2.201 RUN No. 4 FOR Imidacloprid parent ON Citrus * INPUT VALUES * Short photolysis half life ( 0.2 days)  RATE (#/ AC) No. APPS & SOIL SOLUBIL APPL TYPE % CROPPED INCORP ONE( MULT) INTERVAL Koc ( PPM ) (% DRIFT) AREA ( IN)  .250( .496) 2 14 161.0 580.0 AERIAL( 16.0) 87.0 .0 FIELD AND RESERVOIR HALFLIFE VALUES ( DAYS)  METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED ( FIELD) RAIN/ RUNOFF ( RESERVOIR) ( RES. EFF) ( RESER.) ( RESER.)  602.00 2 N/ A .20 24.80 ****** 24.30 UNTREATED WATER CONC ( MICROGRAMS/ LITER ( PPB)) Ver 1.0 AUG 1, 2001  PEAK DAY ( ACUTE) ANNUAL AVERAGE ( CHRONIC) CONCENTRATION CONCENTRATION  35.275 2.175 20 SCI GROW Modeling Results:

SCIGROW VERSION 2.2: NOVEMBER 1, 2001 RUN No. 2 FOR Imidacloprid Parent ** INPUT VALUES **  APP RATE APPS/ TOTAL/ SOIL AEROBIC SOIL METAB ( LBS/ AC) YEAR SEASON KOC HALFLIFE ( DAYS)  .250 2 .500 172.0 340.00 GROUND WATER SCREENING CONCENTRATION ( IN UG/ L  PPB)  1.429716

RUN No. 3 FOR Imidacloprid Total Residues ** INPUT VALUES **  APP RATE APPS/ TOTAL/ SOIL AEROBIC SOIL METAB ( LBS/ AC) YEAR SEASON KOC HALFLIFE ( DAYS)  .250 2 .500 172.0 483.00 GROUND WATER SCREENING CONCENTRATION ( IN UG/ L  PPB)  2.090082

APPENDIX C: Imidacloprid and Degradates Mentioned in this Memorandum 21 22 Appendix D: Environmental Fate and Transport a. Degradation Hydrolysis of Imidacloprid ( 161 1)  Imidacloprid was stable to hydrolysis in pH 5 and 7 buffer solutions, and slowly degraded at pH 9 with an extrapolated half life of 355 days ( MRID 42055337; EFGWB review nos. 92 0210, 92 0196). No degradation products accumulated significantly during the course of the study.

Photolysis in water ( 161 2)  The only environmental fate study in which extensive degradation occurred within a period of hours or a few days was the aqueous photolyis study ( MRID 42256376; EFGWB reviews no. 92 0847, 92 1039, and 92 1042). The possibility of rapid photolysis has some obvious implications for surface water exposure, but should not be assumed to universally occur in surface waters because there is not supporting evidence from surface water monitoring studies, the photolytic rate can be substantially different from distilled water in natural waters, and the amount of pesticide actually exposed to sunlight can be quite low in many surface waters.

Imidacloprid degraded with an " environmental" half life of 4.2 hours ( 0.2 days) in pH 7 buffer solutions maintained at 24 C. The 50% and 75% disappearance times were approximately 1 and 2 hours, respectively.

Residue analysis. Thin layer chromatography ( TLC) in multiple solvent systems and radiometric detection ( exposure of TLC plates to X ray film) was used to confirm the identity of imidacloprid and two degradation products. In addition, residues were also determined with reverse phase high performance liquid chromatography ( HPLC). A linear analyzer was used to quantify residues eluted on TLC plates. Imidacloprid guanidine was the most prominent degradate, accumulating to 17% of the applied imidacloprid at the last sampling interval 2 hours after treatment. The only other degradation product that was identified was imidacloprid urea, which constituted 10% of the applied material 2 hours posttreatment. No effort was made to carry the experiment on to follow the degradation of imidacloprid more completely, and other degradation products were not identified. Two other separated, but unidentified photodegradation products reach maximum levels of 13% and 8% of the applied imidacloprid when the experiment was terminated after 2 hours of irradiation.

The initial concentration of imidacloprid was 5.4 mg/ l ( 5400 ppb) in sterile, buffered solution. The study was conducted with a Xenon lamp rather than natural sunlight ( the study summary mentions that " under natural sunlight 60% of the compound were [ sic] degraded after 4 hours", but a detailed description of the natural sunlight experiment was not provided). The light intensity of the lamp was 8.9 to 9.5 uW/ cm2 compared to 4.1 to 5.3 uW/ cm2 for " sunlight intensity on bright days" at the Yuki Institute in Japan, where the experiment was apparently conducted. Imidacloprid was shown to be more stable in sterile solution kept in the dark, but the last sample was taken only after two hours. 23 This study failed to identify most of the residues by two hours after application, and also failed to demonstrate the long term stability of imidacloprid in the dark control. Although the stability of imidacloprid at pH 7 in solution has been demonstrated in a separate hydrolysis study, this should have been confirmed in the exact same solution that was used for the photolysis study. A further limitation was that the long term stability of imidacloprid degradation products to photolysis was not evaluated.

Photolysis on soil ( 161 3)   Imidacloprid degraded with a registrant calculated second order half life of 39 days ( calculated environmental half life of 171 days). Two experiments were run, one for 5 and the other for 15 days. At the end of the 15 days, imidacloprid parent accounted for 81.6% of the applied radioactivity; consequently an accurate estimate of the degradation rate under the conditions of this test is not possible.

Aerobic soil metabolism ( 162 1)   Imidacloprid degraded in a Kansas sandy loam soil ( series name or classification unknown; MRID 421073501) with a half life well over 1 year ( the duration of the study), extrapolation of the data with assumption of continued decay at a first order rate results in a calculated half life of 660 days ( Table E 1). In contrast, in three European soils ( MRID 452393), the first order half lives were calculated to be 248, 341, and 188 days. The mean first order half life was 359 days ( 90% upper bound confidence value of 520 days); however there appeared to be greater persistence during the latter part of these studies than predicted by a simple first order model. These studies were conducted at 20 C ( except 22 C for the Kansas soil), persistence might have been lower at 25 C, the temperature of most laboratory soil metabolism studies.

Under aerobic conditions no specific compound has been identified as accumulating to 10% or more of the applied in soil or water. The lack of identification of major degradates was a factor of both the limited transformation of parent compound over the duration of these studies and the failure to identify the nature of much of the residues.

Anaerobic soil metabolism ( 162 2)  No anaerobic soil metabolism study has been conducted; however, an anaerobic aquatic soil metabolism study was conducted in lieu of this study.

Anaerobic aquatic soil metabolism ( 162 2)  Imidacloprid degradation was evaluated in a water / sediment mixture ( obtained from a pond in Stilwell, Kansas) ( MRID 42256378). Characteristics of the sediment were: silt loam textural class ( 14% sand, 58% silt, 28% clay), 3.2% organic matter, pH 6.9. The pond water was not characterized. The study was conducted with 500 ml pond water and 100 g of sediment in flasks under unspecified conditions; imidacloprid was added to the overall system at a concentration of 0.56 ppm ( presumably part per million by weight). The incubation flasks were purged with nitrogen and the maintenance of anaerobic conditions was documented with periodic measurement of redox potential, pH, and oxygen concentration. Imidacloprod degraded with a first order anaerobic half life of 27 days over the 358 day postapplication incubation period. Under the anaerobic conditions of this study, imidacloprid underwent a nitro reduction reaction to the degradate imidacloprid guanidine, a compound which 24 accumulated to 66% of applied 249 days after application of parent imidacloprid. Imidacloprid guanidine appears to be extremely persistent under anaerobic conditions; residues of this degradate still represented 64% ( 50% in the sediment and 14% in the water) of the applied imidacloprid at the last sampling date of 358 days posttreatment. Virtually no mineralization of imidacloprid occurred, evolved carbon dioxide represented less than 0.2% of the applied imidacloprid.

b. Mobility Mobility/ Adsorption/ Desorption ( 163 1)  Based on two sets of batch equilibrium studies ( MRID 420553 38  American soils; and M in a total of eight soils ( four American and four German), parent imidacloprid is moderately mobile with Freundlich adsorption coefficients ranging between 0.96 and 4.76. Soil organic carbon partition coefficients ( Koc) values did not vary greatly, the range for eight soils was 132 to 256 ml/ g ( 161 to 239 for the four American soils) with an average Koc of 178. Results for the American and German soil studies are given in Tables E 2 and E 3, respectively. Several articles reflecting further research on imidacloprid sorption in soil have since been published in the open literature, which provide insight into topics such as the increased sorption observed with time and also with lower initial concentrations of imidacloprid in soil water. Sorption coefficients measured in published studies are generally in the same range as the registrant submitted studies, at least over the short term ( Oi, 1999, Cox et al. 1998).

In addition to the above mentioned studies, an aged soil column leaching study with imidacloprid parent ( MRID 420553 39) and an adsorption / desorption study with imidacloprid guanidine ( MRID 425208 02) have been completed. In the imidacloprid guanidine study the same four American soils were studied as with the parent compound ( compare Table E 4 with Table E 2). The degradate was more strongly adsorbed than parent imidacloprid in all four of the test soils.

Prospective ground water studies.

Prospective ground water studies have been conducted at two locations and in both cases the predominant compound detected in soil, soil pore water throughout the vadose zone, and in ground water ( when detectable) was parent imidacloprid. Of the three degradates analyzed for ( imidacloprid guanidine, olefin, and urea derivatives) only imidacloprid urea leached at concentrations that were frequently detectable ( minimum detection limit of 0.02 ug/ L).

There is a possibility that exposure to these degradates could be significant. Therefore, it is important that either specific analytical methods for the degradates or some sort of total residue method for residues in water and soil samples should be developed and made publicly available ( specific methods would be required for any degradate identified as being of toxicological concern).

c. Accumulation 25 Accumulation in Laboratory Fish ( 165 4) This data requirement has been waived. Octanol/ water partitioning ( Kow) data provided by the registrant implies a low potential to bioaccumulate ( Kow for imidacloprid = 3.7 @ 21 C).

d. Field Dissipation Terrestrial field dissipation ( 164 1). Terrestrial field dissipation studies have been submitted from Georgia ( loamy sand, bareground), Minnesota ( sandy loam, planted to corn), California ( sandy loam, planted to tomatoes), Minnesota ( loam, turf plot), and a Georgia loamy sand ( turf plot) ( Table E 5). The dissipation half lives ( based on analyses of 0 6 inch soil cores only) ranged from 107 days to much greater than 1 year ( no significant dissipation over the one year of the study at three of the sites). In each of these studies a single or broadcast application at 0.5 lb ai/ A was made.

e. Special Field Studies Small Scale Prospective Ground Water Monitoring Studies ( 164 1).

The registrant is currently conducting two small scale Prospective Ground Water Monitoring studies: one each in Montcalm County, Michigan and Monterey County, California. In both studies, the registrant is monitoring for imidacloprid parent, imdacloprid guanidine, imdiacloprid olefin, and imidacloprid urea in the vadose zone and in shallow ground water.

In the California study ( located near Salinas, Monterey County) imidacloprid was applied at 0.45 lb ai/ A within the planting furrow ( broccoli crop) in July 1996. At this site, more leaching of imidacloprid residues has been found to occur in the " control" plot than in the treated area. The registrant believes the imidacloprid found in control plot samples is from four foliar applications of imidacloprid in 1995 and 1996. Although it appears that sufficient irrigation water has been applied at this site to facilitate some ground water recharge, interpretation of this study is complicated by the relative insensitivity of the analytical method for the conservative tracer ( bromide) to be used to confirm this. In fact, there have been only a handful of detections of bromide in the first 3+ years of sampling of ground water, providing no definitive evidence that sufficient water has been applied at the site for any pesticide residues to reach ground water. Our conclusion therefore is, that even though there have only been three detections of imidacloprid in ground water ( at 0.09, 0.10 and 0.14 ppb; the method has a claimed ability to quantitate imidacloprid at 0.01 ppb in water samples although apparently only detections above 0.05 ppb have been reported), there still could be substantial potential for imidacloprid to leach to ground water following application to irrigated vegetable or fruit crops in California ( if sufficient water is added and time allowed for the aquifer to be recharged with water from the surface postttreatment). Additionally, we note that all three of the imidacloprid degradates were detected leaching through the vadose zone and there were also a few detections of imidacloprid urea in ground water at the California study site. 26 In the Michigan study ( located near Vestaburg, Montcalm County) imidacloprid was applied at 0.34 lb ai/ A by an unspecified method ( potato crop) May 31, 1996. Imidacloprid has been found to be leaching at a variable rate and concentration in all six of the lysimeter clusters with residues so far having occasionally exceeded 1 ppb at 12 feet, the lowest depth sampled ( Figure 2). Residues in ground water so far are somewhat lower, reaching up to 0.24 ppb ( Figure 3). This study is ongoing, and it appears there may be a potential for higher residue levels to be detected. Note that the Tier 1 screening model concentration of 1.4 ppb is higher than residues observed in ground water but lower than the concentration observed in the deepest soil pore water ( 12 foot depth) at the Michigan study site. Complete breakthrough into ground water had not yet clearly been observed; consequently it is possible that higher concentrations of imidacloprid in ground water could still be observed. Consistent with this is that residues in the deepest soil pore water and in groundwater were increasing in most lysimeter and well clusters at some point during the last year of sampling ( there has been a marked seasonal fluctuation in concentrations in imidacloprid in soil pore water).

f. Other ( non registrant) Ground Water Monitoring Recently, EPA has received several reports summarizing monitoring of ground water that is vulnerable to contamination in New York state ( primarily Long Island). For imidacloprid, there have been about 27 detections of imidacloprid above a detection limit of 0.2 ppb in about 5000 ground water samples taken by the Suffolk County Department of Health Services, to date, with much of the monitoring targeted to areas with known histories of imidacloprid use and previously documented ground water contamination issues. Overall, imidacloprid detections are rare in drinking water wells. Three wells had detections above the model predicted maximum of 1.4 ppb. After closer investigation, however, EPA has concluded that those three wells are not reliable indicators of imidacloprid values that can be expected in groundwater from agricultural use of imidacloprid. The first of these wells is a private well in Mattituck, Long Island in which imidacloprid was found at a level of 6.69 ppb. An investigation by the New York authorities, however, concluded that these high levels were due to misuse of the pesticide in a greenhouse adjacent to the well where imidacloprid contaminated water was drained onto the ground in the immediate vicinity of the well. The second well was one of five shallow monitoring wells installed directly down gradient from imidacloprid use sites for the purpose of monitoring pesticide levels. One of those wells, " Jamesport B 2", showed levels of imidacloprid as high as 2.06 ppb. It was discovered, however, that this well was in all likelihood contaminated as a result of a manmade sump nearby that was constructed to alleviate ponding in the field and directly connected surface water to ground water. Imidacloprid was detected in only one of the other five wells, and the level of imidacloprid detected in the other well did not exceed 0.24 ppb. Finally, imidacloprid has been detected in shallow ground water wells directly downgradient from a site investigating use of tree injection treatments of imidacloprid. The highest level of imidacloprid found in these wells was 3.9 ppb. These wells, however, are not representative of wells used to supply ground water for drinking water. The wells were screened at extremely shallow depths ( screens beginning only 4 to 10 feet from surface) due to the fact that the depth to ground water averaged about five feet. 27 It was concluded by the researchers ( EFED makes no comment on this at this time without further investigation ourselves) that these wells are " no more representative of what would likely occur in drinking water supplies than pesticide concentrations in samples taken from a weir draining an agricultural field are representative of what would occur in a community water supply drawing from a river or reservoir downstream."


[Federal Register Volume 87, Number 214 (Monday, November 7, 2022)]
[Rules and Regulations]
[Pages 66947-66948]
[FR Doc No: 2022-23995]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 71

[Docket No. FAA-2022-0924; Airspace Docket No. 22-ASW-17]
RIN 2120-AA66

Amendment of Class E Airspace; Eagle Lake, TX

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: This action amends the Class E airspace at Eagle Lake, TX.
This action is due to an airspace review conducted as part of the
decommissioning of the Eagle Lake very high frequency (VHF)
omnidirectional range (VOR) as part of the VOR Minimal Operational
Network (MON) Program. The geographic coordinates of the airport are
also being updated to coincide with the FAA's aeronautical database.

DATES: Effective 0901 UTC, February 23, 2023. The Director of the
Federal Register approves this incorporation by reference action under
1 CFR part 51, subject to the annual revision of FAA Order JO 7400.11
and publication of conforming amendments.

ADDRESSES: FAA Order JO 7400.11G, Airspace Designations and Reporting
Points, and subsequent amendments can be viewed online at www.faa.gov/air_traffic/publications/. For further information, you can contact the
Airspace Policy Group, Federal Aviation Administration, 800
Independence Avenue SW, Washington, DC 20591; telephone: (202) 267-
8783.

FOR FURTHER INFORMATION CONTACT: Jeffrey Claypool, Federal Aviation
Administration, Operations Support Group, Central Service Center, 10101
Hillwood Parkway, Fort Worth, TX 76177; telephone<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Authority for This Rulemaking

    The FAA's authority to issue rules regarding aviation safety is
found in Title 49 of the United States Code. Subtitle I, Section 106
describes the authority of the FAA Administrator. Subtitle VII,
Aviation Programs, describes in more detail the scope of the agency's
authority. This rulemaking is promulgated under the authority described
in Subtitle VII, Part A, Subpart I, Section 40103. Under that section,
the FAA is charged with prescribing regulations to assign the use of
airspace necessary to ensure the safety of aircraft and the efficient
use of airspace. This regulation is within the scope of that authority
as it amends the Class E airspace extending upward form 700 feet above
the surface at Eagle Lake Airport, Eagle Lake, TX, to support
instrument flight rule operations at this airport.

History

    The FAA published a notice of proposed rulemaking in the Federal
Register (87 FR 50592; August 17, 2022) for Docket No. FAA-2022-0924 to
amend the Class E airspace at Eagle Lake, TX. Interested parties were
invited to participate in this rulemaking effort by submitting written
comments on the proposal to the FAA. No comments were received.
    Class E airspace designations are published in paragraph 6005 of
FAA Order JO 7400.11G, dated August 19, 2022, and effective September
15, 2022, which is incorporated by reference in 14 CFR 71.1. The Class
E airspace designations listed in this document will be published
subsequently in FAA Order JO 7400.11.

Availability and Summary of Documents for Incorporation by Reference

    This document amends FAA Order JO 7400.11G, Airspace Designations
and Reporting Points, dated August 19, 2022, and effective September
15, 2022. FAA Order JO 7400.11G is publicly available as listed in the
ADDRESSES section of this document. FAA Order JO 7400.11G lists Class
A, B, C, D, and E airspace areas, air traffic service routes, and
reporting points.

The Rule

    This amendment to 14 CFR 71 amends the Class E airspace extending
upward from 700 feet above the surface at Eagle Lake Airport, Eagle
Lake, TX, by removing the Eagle Lake VOR/DME and associated extension
from the airspace legal description; and updates the geographic
coordinates of the airport to coincide with the FAA's aeronautical
database.
    This action is due to an airspace review conducted as part of the
decommissioning of the Eagle Lake VOR, which provided navigation
information for the instrument procedures at these airports, as part of
the VOR MON Program.
    FAA Order JO 7400.11, Airspace Designations and Reporting Points,
is published yearly and effective on September 15.

Regulatory Notices and Analyses

    The FAA has determined that this regulation only involves an
established body of technical regulations for which frequent and
routine amendments are necessary to keep them operationally current, is
non-controversial and unlikely to result in adverse or negative
comments. It, therefore: (1) is not a ``significant regulatory action''
under Executive Order 12866; (2) is not a ``significant rule'' under
DOT Regulatory Policies and Procedures (44 FR 11034; February 26,
1979); and (3) does not warrant preparation of a regulatory evaluation
as the anticipated impact is so minimal. Since this is a routine matter
that only affects air traffic procedures and air navigation, it is
certified that this rule, when promulgated, does not have a significant
economic impact on a substantial number of small entities under the
criteria of the Regulatory Flexibility Act.

Environmental Review

    The FAA has determined that this action qualifies for categorical
exclusion under the National Environmental Policy Act in accordance
with FAA Order 1050.1F, ``Environmental Impacts: Policies and
Procedures,'' paragraph 5-6.5.a. This airspace action is not expected
to cause any potentially significant environmental impacts, and no
extraordinary circumstances exist that warrant preparation of an
environmental assessment.

Lists of Subjects in 14 CFR Part 71

    Airspace, Incorporation by reference, Navigation (air).

Adoption of the Amendment

    In consideration of the foregoing, the Federal Aviation
Administration amends 14 CFR part 71 as follows:

PART 71--DESIGNATION OF CLASS A, B, C, D, AND E AIRSPACE AREAS; AIR
TRAFFIC SERVICE ROUTES; AND REPORTING POINTS

0
1. The authority citation for part 71 continues to read as follows:

    Authority:  49 U.S.C. 106(f), 106(g); 40103, 40113, 40120; E.O.
10854, 24 FR 9565, 3 CFR, 1959-1963 Comp., p. 389.

71.1   [Amended]

0
2. The incorporation by reference in 14 CFR 71.1 of FAA Order JO
7400.11G, Airspace Designations and Reporting Points, dated August 19,
2022, and effective September 15, 2022, is amended as follows:

Paragraph 6005 Class E Airspace Areas Extending Upward From 700
Feet or More Above the Surface of the Earth.

* * * * *

ASW TX E5 Eagle Lake, TX [Amended]

Eagle Lake Airport, TX
    (Lat. 29[deg]36'00'' N, long. 96[deg]19'19'' W)

    That airspace extending upward from 700 feet above the surface
within a 6.4-mile radius of Eagle Lake Airport.

    Issued in Fort Worth, Texas, on October 31, 2022.
Martin A. Skinner,
Acting Manager, Operations Support Group, ATO Central Service Center.
[FR Doc. 2022-23995 Filed 11-4-22; 8:45 am]
BILLING CODE 4910-13-P


[Federal Register Volume 76, Number 173 (Wednesday, September 7, 2011)]
[Proposed Rules]
[Pages 55298-55299]
[FR Doc No: 2011-22881]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 71

[Docket No. FAA-2011-0578; Airspace Docket No. 11-ASO-24]

Proposed Establishment of Class D and E Airspace and Amendment of
Class E; Brooksville, FL

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: This action proposes to establish Class D and E airspace and
amend existing Class E airspace at Brooksville, FL. to accommodate a
new air traffic control tower at Hernando County Airport. Controlled
airspace is necessary for the support of air traffic operations at
Hernando County Airport and would enhance the safety and airspace
management at the airport. This action also would make a minor
adjustment to the geographic coordinates of the airport.

DATES: 0901 UTC. Comments must be received on or before October 24,
2011. The Director of the Federal Register approves this incorporation
by reference action under title 1, Code of Federal Regulations, part
51, subject to the annual revision of FAA, Order 7400.9 and publication
of conforming amendments.

ADDRESSES: Send comments on this rule to: U. S. Department of
Transportation, Docket Operations, West Building Ground Floor, Room
W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590-0001;
Telephone: 1-800-647-5527; Fax:<PHONE_NUMBER>. You must identify the
Docket Number FAA-2011-0578; Airspace Docket No. 11-ASO-24, at the
beginning of your comments. You may also submit and review received
comments through the Internet at http://www.regulations.gov.
    You may review the public docket containing the rule, any comments
received, and any final disposition in person in the Dockets Office
(see ADDRESSES section for address and phone number) between 9 a.m. and
5 p.m., Monday through Friday, except Federal Holidays.
    An informal docket may also be examined during normal business
hours at the office of the Eastern Service Center, Federal Aviation
Administration, Room 350, 1701 Columbia Avenue, College Park, Georgia
30337.

FOR FURTHER INFORMATION CONTACT: John Fornito, Airspace Specialist,
Operations Support Group, Eastern Service Center, Air Traffic
Organization, Federal Aviation Administration, P.O. Box 20636, Atlanta,
Georgia 30320; telephone<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to comment on this rule by
submitting such written data, views, or arguments, as they may desire.
Comments that provide the factual basis supporting the views and
suggestions presented are particularly helpful in developing reasoned
regulatory decisions on the proposal. Comments are specifically

invited on the overall regulatory, aeronautical, economic,
environmental, and energy-related aspects of the proposal.
Communications should identify both docket numbers (FAA-2011-0578;
Airspace Docket No. 11-ASO-24) and be submitted in triplicate to the
Docket Management System (see ADDRESSES section for address and phone
number). You may also submit comments through the Internet at http://www.regulations.gov. Those wishing the FAA to acknowledge receipt of
their comments on this notice must submit with those comments a self-
addressed, stamped postcard on which the following statement is made:
``Comments to Docket No. The postcard will be date/time stamped and
returned to the commenter. All communications received before the
specified closing date for comments will be considered before taking
action on the proposed rule. The proposal contained in this notice may
be changed in light of the comments received. A report summarizing each
substantive public contact with FAA personnel concerned with this
rulemaking will be filed in the docket.

Availability of NPRMs

    An electronic copy of this document may be downloaded from and
comments submitted through http://www.regulations.gov. Recently
published rulemaking documents can also be accessed through the FAA's
Web page at http://www.faa.gov/airports_airtraffic/air_traffic/publications/airspace_amendments/. Additionally, any person may obtain
a copy of this notice by submitting a request to the Federal Aviation
Administration (FAA), Office of Air Traffic Airspace Management, ATA-
400, 800 Independence Avenue, SW., Washington, DC 20591, or by calling
(202) 267-8783. Communications must identify both docket numbers for
this notice. Persons interested in being placed on a mailing list for
future NPRMs should contact the FAA's Office of Rulemaking, (202) 267-
9677, to request a copy of Advisory Circular No. 11-2A, Notice of
Proposed Rulemaking Distribution System, which describes the
application procedure.

The Proposal

    The FAA is considering an amendment to Title 14, Code of Federal
Regulations (14 CFR) part 71 to establish Class D airspace, Class E
surface area airspace and amend Class E airspace extending upward from
700 feet above the surface at Hernando County Airport, Brooksville, FL.
Controlled airspace is necessary to support the operation of the new
air traffic control tower, and new standard instrument approach
procedures, and would enhance the safety and management of aircraft
operations at the airport. Also, to be in concert with the FAAs
aeronautical database, this action would adjust the geographic
coordinates of the airport.
    Class D and E airspace designations are published in Paragraphs
5000, 6002, and 6005 respectively, of FAA Order 7400.9U, dated August
18, 2010, and effective September 15, 2010, which is incorporated by
reference in 14 CFR 71.1. The Class D and E airspace designations
listed in this document will be published subsequently in the Order.
    The FAA has determined that this proposed regulation only involves
an established body of technical regulations for which frequent and
routine amendments are necessary to keep them operationally current.
It, therefore, (1) Is not a ``significant regulatory action'' under
Executive Order 12866; (2) is not a ``significant rule'' under DOT
Regulatory Policies and Procedures (44 FR 11034; February 26, 1979);
and (3) does not warrant preparation of a Regulatory Evaluation as the
anticipated impact is so minimal. Since this is a routine matter that
will only affect air traffic procedures and air navigation, it is
certified that this proposed rule, when promulgated, would not have a
significant economic impact on a substantial number of small entities
under the criteria of the Regulatory Flexibility Act.
    The FAA's authority to issue rules regarding aviation safety is
found in Title 49 of the United States Code. Subtitle I, section 106
describes the authority of the FAA Administrator. Subtitle VII,
Aviation Programs, describes in more detail the scope of the agency's
authority.
    This proposed rulemaking is promulgated under the authority
described in subtitle VII, part, A, subpart I, section 40103. Under
that section, the FAA is charged with prescribing regulations to assign
the use of airspace necessary to ensure the safety of aircraft and the
efficient use of airspace. This proposed regulation is within the scope
of that authority as it proposes to establish and amend controlled
airspace at Hernando County Airport, Brooksville, FL.

Lists of Subjects in 14 CFR Part 71

    Airspace, Incorporation by reference, Navigation (air).

The Proposed Amendment

    In consideration of the foregoing, the Federal Aviation
Administration proposes to amend 14 CFR part 71 as follows:

PART 71--DESIGNATION OF CLASS A, B, C, D, AND E AIRSPACE AREAS; AIR
TRAFFIC SERVICE ROUTES; AND REPORTING POINTS

    1. The authority citation for part 71 will continue to read as
follows:

    Authority: 49 U.S.C. 106(g); 40103, 40113, 40120; E.O. 10854, 24
FR 9565, 3 CFR, 1959-1963 Comp., p. 389.

Sec.  71.1  [Amended]

    2. The incorporation by reference in 14 CFR 71.1 of Federal
Aviation Administration Order 7400.9U, Airspace Designations and
Reporting Points, dated August 18, 2010, and effective September 15,
2010, is amended as follows:

Paragraph 5000 Class D airspace.

* * * * *

ASO FL D Brooksville, FL [New]

Hernando County Airport, FL
    (Lat. 28[deg]28'25'' N., long. 82[deg]27'20'' W.)

    That airspace extending upward from the surface up to and
including 1,500 feet MSL within a 5.1-mile radius of the Hernando
County Airport. This Class D airspace area is effective during
specific dates and times established in advance by a Notice to
Airmen. The effective date and time will thereafter be continuously
published in the Airport/Facility Directory.

Paragraph 6002 Class E airspace designated as surface areas.

* * * * *

ASO FL E2 Brooksville, FL [New]

Hernando County Airport, FL
    (Lat. 28[deg]28'25'' N., long. 82[deg]27'20'' W.)

    That airspace extending from the surface within a 5.1-mile
radius of Hernando County Airport. This Class E airspace area is
effective during specific dates and times established in advance by
a Notice to Airmen. The effective date and time will thereafter be
continuously published in the Airport/Facility Directory.

Paragraph 6005 Class E airspace areas extending upward from 700
feet or more above the surface of the earth.

* * * * *

ASO FL E5 Brooksville, FL [Amended]

Hernando County Airport, FL
    (Lat. 28[deg]28'25'' N., long. 82[deg]27'20'' W.)

    That airspace extending upward from 700 feet above the surface
within a 7.6-mile radius of Hernando County Airport.

    Issued in College Park, Georgia, on August 31, 2011.
Barry A. Knight,
Acting Manager, Operations Support Group, Eastern Service Center, Air
Traffic Organization.
[FR Doc. 2011-22881 Filed 9-6-11; 8:45 am]
BILLING CODE 4910-13-P