**UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY**![](media/image1.png){width="1.3506944444444444in"
height="1.3506944444444444in"}

**WASHINGTON, D.C. 20460**

**MEMORANDUM** **DP Barcodes: DP334029, P334030, DP332756, DP333122,
DP333123, DP333124, DP333125, DP333126, DP330568, DP330569**

> **PC Code: 129099**

**April 13, 2007**

**SUBJECT:** New Use Drinking Water Assessment for Imidacloprid on
Peanuts, Soybeans and IR-4 Registration for Crop Group 13A: Caneberries

TO: Jennifer R. Tyler

RAB1 (7509P)

Health Effects Division

Barbara Madden, Risk manager Reviewer

RIMUERB (7505P)

Registration Division

FROM: Ronald D. Parker, Ph.D. Senior Environmental Engineer

ERB5 (7507P)

Environmental Fate and Effects Division

THRU: Mah Shamim, Branch Chief

ERB5 (7507)

Environmental Fate and Effects Division

**EXECUTIVE SUMMARY**. This memo summarizes estimated drinking water
concentrations (EDWCs) for new uses of Imidacloprid insecticide on
peanuts and soybeans and on IR-4 Crop Group 13A (Caneberries). Exposure
concentration values for all crops were calculated with the FQPA Index
Reservoir Screening Tool (FIRST) which is 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.

Calculated EDWCs for these new Imidacloprid uses do not exceed
concentrations for crops evaluated previously and therefore overall
result of this exposure assessment is unchanged. Assessment results are
as follows in Table 1.

Table 1. Drinking Water EDWCs for Peanuts, Soybeans and Caneberries (CG
13)

+----------+---------------+----------+----------------+-------------+
| Models   | Maximum       | 1/10     | 1/10 Annual    | Avg Annual  |
| Used     | Percent       | Peak     | (Chronic       |             |
|          | Cropped Area  | (Acute)  | non-cancer)    | (Chronic    |
|          | (PCA)         | (ppb)    | (ppb)          | cancer)     |
|          |               |          |                | (ppb)       |
+----------+---------------+----------+----------------+-------------+
| FIRST    | Peanuts       | 9.2      | 4.0            | 4.0         |
|          | (0.87)        |          |                |             |
+----------+---------------+----------+----------------+-------------+
|          |               |          |                |             |
+----------+---------------+----------+----------------+-------------+
| FIRST    | Soybeans      | 4.6      | 2.0            | 2.0         |
|          | (0.41)        |          |                |             |
+----------+---------------+----------+----------------+-------------+
|          |               |          |                |             |
+----------+---------------+----------+----------------+-------------+
| FIRST    | Caneberries   | 35.0     | 15.3           | 15.3        |
|          | (0.87)        |          |                |             |
+----------+---------------+----------+----------------+-------------+

The previous highest acute value was 36.0 (range: 35.4 to 36.0) for
Imidacloprid usage on citrus. The previous highest chronic value was
17.2 (range: 16.5 to 17.2) also for usage on citrus.

A summary of the input parameter values used in the modeling for this
assessment is presented in Table 2 below. The output file for FIRST is
attached in Appendix 1.

**[PROBLEM FORMULATION]{.underline}**

This assessment uses environmental fate and transport computer
simulation modeling to estimate possible human exposure to pesticide in
drinking water which might occur as a result of Imidacloprid application
to the assessed crops. There are a number of possible routes of exposure
by which applied pesticide might reach a drinking water source. A
schematic diagram of possible routes of exposure is presented in Figure
1 below. The main routes are through pesticide runoff to surface waters
or leaching to ground waters which might serve as a source of supply for
a public or private drinking water facility.

For human health exposure assessments undertaken for FQPA, EFED has
developed an "index agricultural watershed-drinking water reservoir" or
"index reservoir" scenario. The concept behind use of a model of an
"index" reservoir to screen pesticides, is that the chosen reservoir --
and its associated characteristics -- would become the standard set of
conditions by which EPA would judge the potential of a pesticide to
contaminate drinking water derived from surface water. The "index"
reservoir was selected from a group of reservoirs that provide drinking
water to communities throughout the country. EPA selected the particular
reservoir because it had characteristics associated with a higher
potential for pesticide contamination of surface water. Because the
"index" reservoir has characteristics that are associated with a higher
potential for pesticide contamination of surface water, the model is
likely to be protective of other drinking water sources which are less
vulnerable to contamination. The reservoir simulated is a small drinking
water reservoir located in Shipman, Illinios. Shipman City Lake is 13
acres in area, 9 feet deep, and has a watershed area of 427 acres. The
"index agricultural watershed-drinking water reservoir" configuration is
moved to simulation sites which are consistent with the growth of the
crop being assessed. The fields associated with the reservoir are
designed as "high-exposure" soil-weather combinations with the goal of
representing a site worse that 90% of the area on which the crop is
grown. True relative vulnerability of the site vis-à-vis the sites which
were not developed for modeling is not known.

**Figure 1. Possible routes of human exposure to pesticide through
drinking water.**

![](media/image2.wmf){width="6.497222222222222in"
height="5.534027777777778in"}

*Background Information on FIRST Fate and Transport Model:*

FIRST is a screening-level computer 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. Lower tiers of assessment such as this one
are designed to screen 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.

It is recognized that most watersheds large enough to support a
community drinking water system (CWS) are not entirely planted in only
one crop. The modeling system, therefore, has developed a method to
consider a maximum percent cropped area (PCA) factor to account for this
fact. Maximum national PCA values are used for each of the crops in this
assessment. PCA values are developed for four major crops based upon
national crop maps. A PCA of 0.87 represents the maximum area of all
other crops in there respective watershed.

**Exposure Assessment Methodology**

A single simulation site is designed to represent the risk of
Imidacloprid usage throughout the national growing area of the crop.
Figure 2 represents the assessment area for soybeans and Figure 3
represents this assessment area for peanuts.

**Peanuts and Soybeans**

The exposure assessment for peanuts and soybeans is based in the
screening-level FIRST model. Calculated EDWCs for these new Imidacloprid
uses do not exceed concentrations for crops evaluated previously and
therefore overall result of this exposure assessment is unchanged. For
this reason a higher tier assessment was not required. A tier 1
assessment such as this, may over-estimate concentrations routinely
found in the environment, but are unlikely to under-estimate
environmental values.

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.

**Figure 2. Peanut Assessment Area (Census of Agriculture, 2002)**

![](media/image3.wmf){width="6.492361111111111in"
height="4.999305555555556in"}

**Figure 3. Peanut Assessment Area (Census of Agriculture, 2002)**

![](media/image4.wmf){width="6.493055555555555in"
height="4.990277777777778in"}

**Crop Group 13A (Caneberrries)**

This exposure assessment also includes application on IR-4 Crop Group
(Caneberries). This group includes the following crops:

> 1). Amur River grape, *Vitis amurensis* Rupr (*Vitaceae*)
>
> 2). Aronia berry, *Aronia spp*. (*Rosaceae*)
>
> 3). Bayberry, *Myrica spp*. (*Myricacea*e)
>
> 4). Bearberry, *Arctostaphylos uva-ursi* (L.) Spreng (*Ericaceae*)
>
> 5). Bilberry, *Vaccinium myrtillus* L. (*Ericaceae)*
>
> 6). Blackberries, *Rubus spp*. (*Rosaceae*)
>
> 7). Blueberry, *Vaccinium spp*. (*Ericaceae*)
>
> 8). Blueberry, Lowbush, *Vaccinium angustifolium* Aiton (*Ericaceae*)
>
> 9). Buffalo Currant, *Ribes aureum* Pursh. (*Grossulariaceae*)
>
> 10). Buffaloberry, *Shepherdia argentea* (Pursh) Nutt.(*Eleagnaceae*)
>
> 11). Che, *Cudrania tricuspidata* Bur. ex Lavallee (*Moraceae*)
>
> 12). Chilean guava, *Myrtus ugni* Mol. (*Myrtaceae*)
>
> 13). Chinese Egg Gooseberry, *Actinidia rubricallus* Dunn
> (*Actinidiaceae*)
>
> 14). Chokecherry, *Prunus virginiana* L. (*Rosaceae*)
>
> 15). Cloudberry, *Rubus chamaemorus* L. (*Rosaceae*)
>
> 16). Cranberry, *Vaccinium macrocarpon* Aiton (*Ericaceae*)
>
> 17). Currant, Black, *Ribes nigrum* L. \[*Grossulariaceae*
> (*Saxifragaceae*)\], and Currant, Red, *Ribes rubrum* L. (syn: *R.
> sativum* (Rchb.) Syme) \[*Grossulariaceae* (*Saxifragaceae*)\]
>
> 18). Elderberry, *Sambucus spp*. (*Caprifoliaceae*)
>
> 19). European Barberry, *Berberis vulgaris* L. (*Berberidaceae*)
>
> 20). Gooseberry, *Ribes spp*. \[*Grossulariaceae* (*Saxifragaceae*)\]
>
> 21). Grape, *Vitis spp*. (*Vitaceae*)
>
> 22). Highbush cranberry, *Viburnum opulus L. var. Americanum* Aiton
> (*Caprifoliaceae*)
>
> 23). Honeysuckle, *Lonicera caerula L. var. emphyllocalyx* Nakai
> (*Caprifoliaceae*)
>
> 24). Huckleberry, *Gaylussacia spp*. (*Ericaceae*)
>
> 25). Jostaberry, *Ribes x nidigrolaria* Rud. Bauer & A. Bauer.
> \[*Grossulariaceae* (*Saxifragaceae*)\]
>
> 26). Juneberry (including Saskatoon Berry), *Amelanchier spp*.
> (*Rosaceae*)
>
> 27). Kiwifruit, fuzzy, *Actinidia deliciosa* (A. Chev.) C.F. Liang &
> A.R. Ferguson (*Actinidaceae*)
>
> 28). Kiwifruit, hardy, *Actinidia arguta* (Siebold & Zucc.) Planch. Ex
> Miq (*Actinidaceae*)
>
> 29). Lingonberry, *Vaccinium vitis‑idaea* L. (*Ericaceae*)
>
> 30). Maypop, *Passiflora incarnata* L. (*Passifloraceae*)
>
> 31). Mountain Pepper Berries, *Tasmannia lanceolata* (Poir.) A.C.
> Sm.(*Winteraceae*)
>
> 32). Mulberry, *Morus spp*. (*Moraceae*)
>
> 33). Muntries, *Kunzea pomifera* F. Muell. (*Myrtaceae*)
>
> 34). Native Currant, *Acrotriche depressa* R. Br. (*Epacridaceae*)
>
> 35). Partridgeberry, *Mitchella repens* L. (*Rubiaceae*)
>
> 36). Phalsa, *Grewia subinaequalis* DC. (*Tiliaceae*)
>
> 37). Pincherry, *Prunus pensylvanica* L. f. (*Rosaceae*)
>
> 38). Raspberries*, Rubus spp*. (*Rosaceae*)
>
> 39). Riberry, *Syzygium luehmannii* (*Myrtaceae*)
>
> 40). Salal, *Gaultheria shallon* Pursh (Ericaceae)
>
> 41\) Schisandra berry (*Schisandra chinensis* (Turcz.) Baill.
> (*Schisandraceae*)
>
> 42). Sea Buckthorn, *Hippophae rhamnoides* L. (*Eleagnaceae*)
>
> 43). Serviceberry, *Sorbus spp*. (*Rosaceae*)
>
> 44). Strawberry, *Fragaria x ananassa* Duchesne, (*Rosaceae*)
>
> 45). Wild raspberry, *Rubus muelleri* Lefevre ex P.J. Mull
> (*Rosaceae*)

Approximately two-thirds of US blackberry/raspberry production occurs in
the states of Washington and Oregon, but 33 other states also report
some production. Harvest data from 2002 is presented in Figure 1 and 2.

Figure 4. Map of Blackberry Harvested Acres.

![](media/image5.png){width="6.488888888888889in"
height="5.020138888888889in"}

Figure 5. Map of the Raspberry Harvested Acres.

![](media/image6.png){width="6.495138888888889in"
height="5.020138888888889in"}**2005 - BLACKBERRIES (
[[http://www.oregon-berries.com/cx6/Worldwide_Production_of_Blackberries_Strik_3-2006_acres.pdf]{.underline}](http://www.oregon-berries.com/cx6/Worldwide_Production_of_Blackberries_Strik_3-2006_acres.pdf_)
)**

USA = 11,905 acres

Oregon = 7,755 acres

California = 700 acres

Texas = 680 acres

Arkansas = 600 acres

Georgia = 315 acres

North Carolina = 125 to 250 acres

Ohio = 125 to 250 acres

Virginia = 125 to 250 acres

Washington = 125 to 250 acres

Another 26 states reported from 5 to 125 acres of blackberries.

**Strik, B.C. et al., 2006**

**Crop and State Acreage Harvested (
www.epa.gov/oppsrrd1/op/azinphos/bead\_ Caneberry 1.pdf )**

Raspberries, Washington = 9,500 acres

Raspberries, Oregon = 4,100

Raspberries, California = 1,800

Blackberries, Oregon = 5,850

**Source: Oregon Ag. Stat. Service, 2000.**

**[ANALYSIS]{.underline}**

# 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 4a. IR-4 Application to Caneberries (Crop Group 13A)

+----------------+------------+-----------------+-----------+---------+
| Formulation    | Number     | Application     | Max Per   | Pre-    |
|                | Appls      | Rate            | Season    | Harvest |
| (% active      |            |                 | fluid oz  | I       |
| ingredient)    | (Min       | fluid oz (lbs)  | (lbs) /   | nterval |
|                | Interval)  | / acre          | acre      | (days)  |
+----------------+------------+-----------------+-----------+---------+
| Admire® 2      | 1-2 (not   | 16.0-32.0       | 32.0      | 7       |
| Flowable       | given)     | (0.25-0.50)     | (0.50)    |         |
|                |            |                 |           |         |
| (21.4%)        |            |                 |           |         |
+----------------+------------+-----------------+-----------+---------+
| PROVADO® 1.6   | 3 (7)      | 8.0 (0.10)      | 24.0      | 3       |
| Flowable       |            |                 | (0.30)    |         |
| (17.4%)        |            |                 |           |         |
+----------------+------------+-----------------+-----------+---------+
| PROVADO® 70 WG | 3 (7)      | 2.3 (0.10)      | 6.9       | 3       |
|                |            |                 | (0.30)    |         |
| (70%)          |            |                 |           |         |
+----------------+------------+-----------------+-----------+---------+
| PROVADO® PRO   | 3 (7)      | 8.0 (0.10)      | 24.0      | 3       |
|                |            |                 | (0.30)    |         |
| (16.5%)        |            |                 |           |         |
+----------------+------------+-----------------+-----------+---------+
| GAUCHO® 550 SC | 1-2 (not   | 7.0-14.0        | 14.0      | 7       |
|                | given)     | (0.25-0.50)     | (0.50)    |         |
| (42.8%)        |            |                 |           |         |
+----------------+------------+-----------------+-----------+---------+

Table 4b. Application to Soybeans

+----------------+-------------+---------------+-----------+---------+
| Formulation    | Number      | Application   | Max Per   | Pre-    |
|                | Appls       | Rate -        | Season -  | Harvest |
| (% active      |             |               | fluid oz  | I       |
| ingredient)    | (Min        | fluid oz      | (lbs) /   | nterval |
|                | Interval)   | (lbs) / acre  | acre      | (days)  |
+----------------+-------------+---------------+-----------+---------+
| ENCORE         | 3 (7)       | 1.50 (0.047)  | 4.50      | 7       |
|                |             |               | (0.14)    |         |
| (40.7%)        |             |               |           |         |
+----------------+-------------+---------------+-----------+---------+
| TRIMAX^TM^ PRO | 3 (7)       | 1.35 (0.047)  | 4.05      | 7       |
|                |             |               | (0.14)    |         |
| (40.7%)        |             |               |           |         |
+----------------+-------------+---------------+-----------+---------+

Table 4c. Application to Peanuts (only)

+----------------+-------------+---------------+-----------+---------+
| Formulation    | Number      | Application   | Max Per   | Pre-    |
|                | Appls       | Rate -        | Season -  | Harvest |
| (% active      |             |               | fluid oz  | I       |
| ingredient)    | (Min        | fluid oz      | (lbs) /   | nterval |
|                | Interval)   | (lbs) / acre  | acre      | (days)  |
+----------------+-------------+---------------+-----------+---------+
| PROVADO® PRO   | 3 (5)       | 3.5 (0.044)   | 10.5      | 14      |
|                |             |               | (0.13)    |         |
| (16.5%)        |             |               |           |         |
+----------------+-------------+---------------+-----------+---------+
| GAUCHO® 75 ST  | 1 (N/A)     | 0.67-1.33 fl  |           | N/A     |
|                |             | oz /cwt       |           |         |
| (seed          |             |               |           |         |
| treatment      |             |               |           |         |
| only)          |             |               |           |         |
+----------------+-------------+---------------+-----------+---------+

Table 4d. IR-4 Application to Peanuts, Proso millet, pearl millet, kava,
oats, artichoke

+-----------------+-------------+---------------+-----------+---------+
| Formulation     | Number      | Application   | Max Per   | Pre-    |
|                 | Appls       | Rate -        | Season -  | Harvest |
| (% active       |             |               | fluid oz  | I       |
| ingredient)     | (Min        | fluid oz      | (lbs) /   | nterval |
|                 | Interval)   | (lbs) / acre  | acre      | (days)  |
+-----------------+-------------+---------------+-----------+---------+
| Admire® 2       | 1 (peanuts) | 16.0-24       | 24.0      | 14      |
| Flowable        |             | .0(0.25-0.38) | (0.38)    |         |
|                 | 1-2         |               | 32.0      | 7       |
| (21.4%)         | (artichoke) | 16.0-32       | (0.50)    |         |
|                 |             | .0(0.25-0.50) |           | 21      |
|                 | 1 (kava)    |               | 24.0      |         |
|                 |             | 10.0-24       | (0.38)    |         |
|                 |             | .0(0.16-0.38) |           |         |
+-----------------+-------------+---------------+-----------+---------+
| PROVADO® 1.6    | 3 (5)       | 3.5 (0.044)   | 10.5      | 14      |
| Flowable        | (peanuts)   |               | (0.13)    |         |
| (17.4%)         |             | 4.0-10.0      |           | 7       |
|                 | 4(14)       | (0.05-0.10)   | 40.0      |         |
|                 | (artichoke) |               | (0.50)    | 7       |
|                 | 3(5) (kava) | 3.5 (0.044)   |           |         |
|                 |             |               | 10.5      |         |
|                 |             |               | (0.13)    |         |
+-----------------+-------------+---------------+-----------+---------+
| PROVADO® 70 WG  | 3 (5)       | 1.0 (0.044)   | 3.0       | 14      |
|                 | (peanuts)   |               | (0.13)    |         |
| (70%)           |             | 1.1-2.9       |           | 7       |
|                 | 4(14)       | (0.05-0.10)   | 11.5      |         |
|                 | (artichoke) |               | (0.50)    | 7       |
|                 | 3(5) (kava) | 1.0 (0.044)   |           |         |
|                 |             |               | 3.0       |         |
|                 |             |               | (0.13)    |         |
+-----------------+-------------+---------------+-----------+---------+
| GAUCHO® 480     | (millet)    | 8.0 fl oz/cwt |           |         |
| Flowable        |             |               |           |         |
| (40.7%)         | (barley)    | 1.0-3.0 fl    |           |         |
|                 |             | oz/cwt        |           |         |
| (seed treatment | (oats)      |               |           |         |
| only)           |             | 1.0-3.0 fl    |           |         |
|                 |             | oz/cwt        |           |         |
+-----------------+-------------+---------------+-----------+---------+
| GAUCHO® 550 SC  | 1 (peanuts) | 7.0-10        | 10.5      | 14      |
|                 |             | .5(0.25-0.38) | (0.38)    |         |
| (42.8%)         | 1-2         |               | 14.0      | 7       |
|                 | (artichoke) | 7.0-14        | (0.50)    |         |
|                 |             | .0(0.25-0.50) |           | 21      |
|                 | 1 (kava)    |               | 10.5      |         |
|                 |             | 4.4-10        | (0.38)    |         |
|                 |             | .5(0.16-0.38) |           |         |
+-----------------+-------------+---------------+-----------+---------+
| GAUCHO® 600     | (oats,      | 8.0 fl oz/cwt |           |         |
| Flowable        | barley,     |               |           |         |
| (48.7%)         | millet)     |               |           |         |
|                 |             |               |           |         |
| (seed treatment |             |               |           |         |
| only)           |             |               |           |         |
+-----------------+-------------+---------------+-----------+---------+
| GAUCHO® 600 SC  | 1 (peanut)  | 6.4-9.6       | 9.6       | 14      |
|                 | 1-2         | (0.26-0.38)   | (0.38)    |         |
| (48.7%)         | (artichoke) |               |           | 7       |
|                 |             | 6.4-12.8      | 12.8      |         |
|                 | 1 (kava)    | (0.25-0.50)   | (0.50)    | 21      |
|                 |             |               |           |         |
|                 |             | 6.4-9.6       | 9.6       |         |
|                 |             | (0.26-0.38)   | (0.38)    |         |
+-----------------+-------------+---------------+-----------+---------+

**Table 2. FIRST Input Parameters for Imidacloprid New Uses**.

+---------------------------+----------+-------------------------------+
| Parameter                 | Input    | Source                        |
+---------------------------+----------+-------------------------------+
| Solubility (ppm)          | 580      | Product chemistry submissions |
+---------------------------+----------+-------------------------------+
| Hydrolysis t~1/2~ @ pH 7  | Stable   | MRID 42055337                 |
| (days)                    |          |                               |
+---------------------------+----------+-------------------------------+
| Aerobic soil t~1/2~       | 520      | MRIDs 452393‑01, 02,          |
| (days)                    |          | 42073501; 90% upper bound     |
|                           |          | confidence limit of mean      |
+---------------------------+----------+-------------------------------+
| Aerobic aquatic t~1/2~    | 1040     | 2x the aerobic soil input     |
| (days)                    |          | value, per EFED guidance      |
|                           |          | document                      |
+---------------------------+----------+-------------------------------+
| Photolysis t~1/2~ in      | 39       | Input guidance & MRIDs        |
| water (days)              |          | 42256376; 42256377            |
+---------------------------+----------+-------------------------------+
| Organic carbon partition  | 178      | MRIDs 425208-01 and 420553-38 |
| coefficient - K~oc~       |          |                               |
| (mL/g)                    |          |                               |
+---------------------------+----------+-------------------------------+
| Application rates (lb     | 0.5      | Label maximum rate for Tree   |
| a.i./Acre)                |          | 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)               |
+---------------------------+----------+-------------------------------+

Table 1. Drinking Water EDWCs for Peanuts and Soybeans

+-----------+---------------+---------+------------------+-------------+
| Conc      | Crop (PCA)    | 1/10    | 1/10 Annual      | Avg Annual  |
| entration |               | Peak    | (Chronic         |             |
| Duration  |               | (Acute) | non-cancer)      | (Cancer)    |
+-----------+---------------+---------+------------------+-------------+
| Conc.     | Peanuts       | 9.2     | 4.0              | 4.0         |
| (ppb)     | (0.87)        |         |                  |             |
+-----------+---------------+---------+------------------+-------------+
|           |               |         |                  |             |
+-----------+---------------+---------+------------------+-------------+
| Conc      | Crop (PCA)    | 1/10    | 1/10 Annual      | Avg Annual  |
| entration |               | Peak    | (Chronic         |             |
| Duration  |               | (Acute) | non-cancer)      | (Cancer)    |
+-----------+---------------+---------+------------------+-------------+
| Conc.     | Soybeans      | 4.6     | 2.0              | 2.0         |
| (ppb)     | (0.41)        |         |                  |             |
+-----------+---------------+---------+------------------+-------------+
|           |               |         |                  |             |
+-----------+---------------+---------+------------------+-------------+

**Appendix 1a. FIRST Results for Caneberries, Peanuts and Soybeans**

RUN No. 1 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 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 1040.0 855.93

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)

CONCENTRATION CONCENTRATION

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

36. 15.287

RUN No. 1 FOR Imidacloprid ON Peanuts \* INPUT VALUES \*

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP

ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

.044( .131) 3 5 178.0 580.0 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 1040.0 855.93

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)

CONCENTRATION CONCENTRATION

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

9.189 4.010

RUN No. 2 FOR Imidacloprid ON Soybeans \* INPUT VALUES \*

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP

ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

.047( .140) 3 7 178.0 580.0 GROUND( 6.4) 41.0 .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 1040.0 855.93

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)

CONCENTRATION CONCENTRATION

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

4.614 2.013

**Appendix B. February 2003 Imidacloprid Drinking Water Assessment**

![](media/image7.png){width="1.0333333333333334in" height="0.9625in"}

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]{.underline}** 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 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.]{.underline}** 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); K~oc~ 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. guanidine[^1] [^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 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.

  ------------------- ----------------------- --------------- -----------------------
  **Chemical**        **[Surface Water                        **[Groundwater
                      (ug/L)]{.underline}**                   (ug/L)]{.underline}**

                      **Acute**               **Chronic**     **Acute and Chronic**

  Imidacloprid parent 35.28 to 35.89          2.18 to 16.52   1.43

  Imidacloprid total  35.42 to 36.04          2.20 to 17.24   2.09
  residues                                                    
  ------------------- ----------------------- --------------- -----------------------

**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   0           MRID 42055337
  7) (days)                              

  Aerobic soil t~1/2~ (days) 1016        MRIDs 452393‑01, 02, 42073501;
                                         90% upper bound confidence limit
                                         of mean

  Aerobic aquatic t~1/2~     2031        2x the aerobic soil input value,
  (days)                                 per EFED guidance document

  Photolysis t~1/2~ in water **0.2 to    Input guidance & MRIDs 42256376;
  (days)                     39^1^**     42256377

  Organic carbon partition   162         MRIDs 425208-01 and 420553-38
  coefficient - K~oc~ (mL/g)             

  Application rate (lb       0.25        Label ‑max. rate for citrus
  a.i./Acre)                             (foliar application)

  \# applications/year       2           Label maximum for citrus
  -------------------------- ----------- ---------------------------------

**Table 3.** SCI‑GROW input parameters for Imidacloprid.

  --------------------------- ----------- ----------------------------------
  **Parameter**               **Input**   **Source**

  Aerobic soil metabolism     483         MRIDs 452393‑01, 02, & 03;
  t~1/2~ (days)                           42073501; mean value

  K~oc~ (mL/g)                172         MRIDs 425208-01 and 420553-38

  Application rate (lb        0.5         Label ‑max. rate for citrus
  a.i./Acre)                              
  --------------------------- ----------- ----------------------------------

**[Review of Degradate Monitoring Data]{.underline}:**

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]{.underline} 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
  -------------------- ------------- ------------ ------------ ------------

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.

**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**

![](media/image8.png){width="2.327777777777778in"
height="1.7180555555555554in"}![](media/image9.png){width="2.11875in"
height="1.738888888888889in"}

![](media/image10.png){width="2.129166666666667in"
height="1.5006944444444446in"}

![](media/image11.png){width="2.1180555555555554in"
height="1.5402777777777779in"}

## 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.

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
post-application incubation period. Under the anaerobic conditions of
this study, imidacloprid underwent a nitro-reduction reaction to the
degradate imidacloprid guanidine, a compound which 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***

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.

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. 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.\"

stored as NCPnutIRAM1.out

Chemical: Imidacloprid

PRZM environment: NCpeanutC.txt modified Satday, 12 October 2002 at
15:12:46

EXAMS environment: ir298.exv modified Thuday, 29 August 2002 at 14:34:12

Metfile: w13737.dvf modified Wedday, 3 July 2002 at 08:06:30

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 8.1 7.953 7.367 6.508 5.93 2.519

1962 3.863 3.827 3.696 3.464 3.194 1.713

1963 11.14 10.92 10.15 8.586 7.616 3.199

1964 2.483 2.439 2.265 2.063 1.878 1.353

1965 2.228 2.188 2.028 1.732 1.583 0.8783

1966 4.888 4.831 4.669 4.236 3.88 1.76

1967 2.51 2.482 2.437 2.155 1.951 1.026

1968 3.475 3.412 3.159 2.73 2.437 1.171

1969 3.227 3.168 2.956 2.748 2.535 1.238

1970 3.921 3.871 3.614 3.088 3.035 1.609

1971 2.678 2.654 2.582 2.304 2.088 1.095

1972 2.966 2.913 2.725 2.57 2.421 1.185

1973 4.622 4.54 4.348 4.201 3.882 1.779

1974 2.979 2.925 2.721 2.392 2.177 1.179

1975 5.882 5.778 5.36 5.112 4.922 2.463

1976 4.409 4.328 4.052 3.441 3.062 1.553

1977 4.356 4.302 4.01 3.616 3.311 1.596

1978 5.522 5.438 5.292 4.991 4.598 2.16

1979 8.897 8.763 8.513 7.559 6.885 3.324

1980 8.085 7.962 7.38 6.253 5.559 2.761

1981 1.969 1.934 1.833 1.682 1.58 1.022

1982 2.115 2.076 1.936 1.667 1.501 0.7642

1983 4.422 4.376 4.118 3.795 3.55 1.646

1984 10.77 10.58 9.798 8.374 7.946 3.867

1985 3.776 3.708 3.549 3.099 2.827 1.675

1986 3.755 3.704 3.471 3.128 2.893 1.429

1987 4.329 4.257 4.051 3.843 3.598 1.703

1988 2.561 2.538 2.448 2.258 2.073 1.082

1989 2.865 2.812 2.607 2.271 2.166 1.144

1990 2.346 2.304 2.155 2.009 1.895 0.9624

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 11.14 10.92 10.15 8.586 7.946 3.867

0.0645161290322581 10.77 10.58 9.798 8.374 7.616 3.324

0.0967741935483871 8.897 8.763 8.513 7.559 6.885 3.199

0.129032258064516 8.1 7.962 7.38 6.508 5.93 2.761

0.161290322580645 8.085 7.953 7.367 6.253 5.559 2.519

0.193548387096774 5.882 5.778 5.36 5.112 4.922 2.463

0.225806451612903 5.522 5.438 5.292 4.991 4.598 2.16

0.258064516129032 4.888 4.831 4.669 4.236 3.882 1.779

0.290322580645161 4.622 4.54 4.348 4.201 3.88 1.76

0.32258064516129 4.422 4.376 4.118 3.843 3.598 1.713

0.354838709677419 4.409 4.328 4.052 3.795 3.55 1.703

0.387096774193548 4.356 4.302 4.051 3.616 3.311 1.675

0.419354838709677 4.329 4.257 4.01 3.464 3.194 1.646

0.451612903225806 3.921 3.871 3.696 3.441 3.062 1.609

0.483870967741936 3.863 3.827 3.614 3.128 3.035 1.596

0.516129032258065 3.776 3.708 3.549 3.099 2.893 1.553

0.548387096774194 3.755 3.704 3.471 3.088 2.827 1.429

0.580645161290323 3.475 3.412 3.159 2.748 2.535 1.353

0.612903225806452 3.227 3.168 2.956 2.73 2.437 1.238

0.645161290322581 2.979 2.925 2.725 2.57 2.421 1.185

0.67741935483871 2.966 2.913 2.721 2.392 2.177 1.179

0.709677419354839 2.865 2.812 2.607 2.304 2.166 1.171

0.741935483870968 2.678 2.654 2.582 2.271 2.088 1.144

0.774193548387097 2.561 2.538 2.448 2.258 2.073 1.095

0.806451612903226 2.51 2.482 2.437 2.155 1.951 1.082

0.838709677419355 2.483 2.439 2.265 2.063 1.895 1.026

0.870967741935484 2.346 2.304 2.155 2.009 1.878 1.022

0.903225806451613 2.228 2.188 2.028 1.732 1.583 0.9624

0.935483870967742 2.115 2.076 1.936 1.682 1.58 0.8783

0.967741935483871 1.969 1.934 1.833 1.667 1.501 0.7642

0.1 8.8173 8.6829 8.3997 7.4539 6.7895 3.1552

Average of yearly averages: 1.6952

Inputs generated by pe4.pl - 8-August-2003

Data used for this run:

Output File: NCPnutIRAM1

Metfile: w13737.dvf

PRZM scenario: NCpeanutC.txt

EXAMS environment file: ir298.exv

Chemical Name: Imidacloprid

Description Variable Name Value Units Comments

Molecular weight mwt 255.6633 g/mol

Henry\'s Law Const. henry 4.0e-12 atm-m\^3/mol

Vapor Pressure vapr 1.5e-9 torr

Solubility sol 580 mg/L

Kd Kd mg/L

Koc Koc 178 mg/L

Photolysis half-life kdp 39 days Half-life

Aerobic Aquatic Metabolism kbacw 1040 days Halfife

Anaerobic Aquatic Metabolism kbacs 81 days Halfife

Aerobic Soil Metabolism asm 520 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0.0 cm

Application Rate: TAPP .0143 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.064 fraction of application rate applied to pond

Application Date Date 05-04 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 2 days Set to 0 or delete line for single app.

Interval 2 interval 2 days Set to 0 or delete line for single app.

Interval 3 interval 2 days Set to 0 or delete line for single app.

Interval 4 interval 2 days Set to 0 or delete line for single app.

Interval 5 interval 2 days Set to 0 or delete line for single app.

Interval 6 interval 2 days Set to 0 or delete line for single app.

Interval 7 interval 2 days Set to 0 or delete line for single app.

Interval 8 interval 2 days Set to 0 or delete line for single app.

Interval 9 interval 2 days Set to 0 or delete line for single app.

Interval 10 interval 2 days Set to 0 or delete line for single app.

Interval 11 interval 2 days Set to 0 or delete line for single app.

Interval 12 interval 2 days Set to 0 or delete line for single app.

Interval 13 interval 2 days Set to 0 or delete line for single app.

Interval 14 interval 2 days Set to 0 or delete line for single app.

Interval 15 interval 2 days Set to 0 or delete line for single app.

Interval 16 interval 2 days Set to 0 or delete line for single app.

Interval 17 interval 2 days Set to 0 or delete line for single app.

Interval 18 interval 2 days Set to 0 or delete line for single app.

Interval 19 interval 2 days Set to 0 or delete line for single app.

Interval 20 interval 2 days Set to 0 or delete line for single app.

Interval 21 interval 2 days Set to 0 or delete line for single app.

Interval 22 interval 2 days Set to 0 or delete line for single app.

Interval 23 interval 2 days Set to 0 or delete line for single app.

Interval 24 interval 2 days Set to 0 or delete line for single app.

Interval 25 interval 2 days Set to 0 or delete line for single app.

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR IR

Flag for runoff calc. RUNOFF total none, monthly or total(average of
entire run)

stored as NCPnutIRAM2.out

Chemical: Imidacloprid

PRZM environment: NCpeanutC.txt modified Satday, 12 October 2002 at
15:12:46

EXAMS environment: ir298.exv modified Thuday, 29 August 2002 at 14:34:12

Metfile: w13737.dvf modified Wedday, 3 July 2002 at 08:06:30

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 7.66 7.521 6.965 6.07 5.551 2.37

1962 3.818 3.766 3.64 3.43 3.16 1.676

1963 11.79 11.57 10.74 9.091 8.063 3.364

1964 2.56 2.515 2.335 2.134 1.931 1.397

1965 2.255 2.214 2.052 1.752 1.594 0.8817

1966 4.894 4.821 4.67 4.259 3.901 1.774

1967 2.402 2.38 2.344 2.085 1.892 1.006

1968 3.381 3.319 3.072 2.657 2.371 1.115

1969 3.357 3.295 3.074 2.832 2.62 1.273

1970 4.079 4.026 3.759 3.213 3.151 1.671

1971 2.761 2.728 2.662 2.374 2.154 1.13

1972 2.947 2.894 2.71 2.496 2.369 1.173

1973 4.384 4.306 4.108 3.94 3.662 1.695

1974 2.793 2.742 2.552 2.254 2.027 1.072

1975 5.6 5.5 5.099 4.794 4.615 2.333

1976 4.561 4.477 4.192 3.56 3.168 1.584

1977 4.32 4.259 3.978 3.559 3.268 1.581

1978 5.65 5.581 5.416 5.147 4.75 2.228

1979 8.434 8.3 8.088 7.191 6.521 3.162

1980 8.464 8.326 7.723 6.545 5.818 2.845

1981 2.04 2.003 1.901 1.734 1.626 1.058

1982 2.116 2.089 1.957 1.687 1.517 0.7739

1983 4.559 4.494 4.239 3.915 3.663 1.688

1984 10.34 10.15 9.399 7.971 7.344 3.622

1985 3.979 3.907 3.754 3.253 2.974 1.714

1986 3.576 3.544 3.334 2.992 2.775 1.392

1987 4.285 4.215 3.986 3.737 3.519 1.672

1988 2.49 2.463 2.382 2.205 2.031 1.068

1989 2.772 2.721 2.521 2.149 2.016 1.064

1990 2.363 2.32 2.161 2.004 1.883 0.9564

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 11.79 11.57 10.74 9.091 8.063 3.622

0.0645161290322581 10.34 10.15 9.399 7.971 7.344 3.364

0.0967741935483871 8.464 8.326 8.088 7.191 6.521 3.162

0.129032258064516 8.434 8.3 7.723 6.545 5.818 2.845

0.161290322580645 7.66 7.521 6.965 6.07 5.551 2.37

0.193548387096774 5.65 5.581 5.416 5.147 4.75 2.333

0.225806451612903 5.6 5.5 5.099 4.794 4.615 2.228

0.258064516129032 4.894 4.821 4.67 4.259 3.901 1.774

0.290322580645161 4.561 4.494 4.239 3.94 3.663 1.714

0.32258064516129 4.559 4.477 4.192 3.915 3.662 1.695

0.354838709677419 4.384 4.306 4.108 3.737 3.519 1.688

0.387096774193548 4.32 4.259 3.986 3.56 3.268 1.676

0.419354838709677 4.285 4.215 3.978 3.559 3.168 1.672

0.451612903225806 4.079 4.026 3.759 3.43 3.16 1.671

0.483870967741936 3.979 3.907 3.754 3.253 3.151 1.584

0.516129032258065 3.818 3.766 3.64 3.213 2.974 1.581

0.548387096774194 3.576 3.544 3.334 2.992 2.775 1.397

0.580645161290323 3.381 3.319 3.074 2.832 2.62 1.392

0.612903225806452 3.357 3.295 3.072 2.657 2.371 1.273

0.645161290322581 2.947 2.894 2.71 2.496 2.369 1.173

0.67741935483871 2.793 2.742 2.662 2.374 2.154 1.13

0.709677419354839 2.772 2.728 2.552 2.254 2.031 1.115

0.741935483870968 2.761 2.721 2.521 2.205 2.027 1.072

0.774193548387097 2.56 2.515 2.382 2.149 2.016 1.068

0.806451612903226 2.49 2.463 2.344 2.134 1.931 1.064

0.838709677419355 2.402 2.38 2.335 2.085 1.892 1.058

0.870967741935484 2.363 2.32 2.161 2.004 1.883 1.006

0.903225806451613 2.255 2.214 2.052 1.752 1.626 0.9564

0.935483870967742 2.116 2.089 1.957 1.734 1.594 0.8817

0.967741935483871 2.04 2.003 1.901 1.687 1.517 0.7739

0.1 8.461 8.3234 8.0515 7.1264 6.4507 3.1303

Average of yearly averages: 1.6780

Inputs generated by pe4.pl - 8-August-2003

Data used for this run:

Output File: NCPnutIRAM2

Metfile: w13737.dvf

PRZM scenario: NCpeanutC.txt

EXAMS environment file: ir298.exv

Chemical Name: Imidacloprid

Description Variable Name Value Units Comments

Molecular weight mwt 255.6633 g/mol

Henry\'s Law Const. henry 4.0e-12 atm-m\^3/mol

Vapor Pressure vapr 1.5e-9 torr

Solubility sol 580 mg/L

Kd Kd mg/L

Koc Koc 178 mg/L

Photolysis half-life kdp 39 days Half-life

Aerobic Aquatic Metabolism kbacw 1040 days Halfife

Anaerobic Aquatic Metabolism kbacs 81 days Halfife

Aerobic Soil Metabolism asm 520 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0.0 cm

Application Rate: TAPP .0143 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.064 fraction of application rate applied to pond

Application Date Date 06-04 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 2 days Set to 0 or delete line for single app.

Interval 2 interval 2 days Set to 0 or delete line for single app.

Interval 3 interval 2 days Set to 0 or delete line for single app.

Interval 4 interval 2 days Set to 0 or delete line for single app.

Interval 5 interval 2 days Set to 0 or delete line for single app.

Interval 6 interval 2 days Set to 0 or delete line for single app.

Interval 7 interval 2 days Set to 0 or delete line for single app.

Interval 8 interval 2 days Set to 0 or delete line for single app.

Interval 9 interval 2 days Set to 0 or delete line for single app.

Interval 10 interval 2 days Set to 0 or delete line for single app.

Interval 11 interval 2 days Set to 0 or delete line for single app.

Interval 12 interval 2 days Set to 0 or delete line for single app.

Interval 13 interval 2 days Set to 0 or delete line for single app.

Interval 14 interval 2 days Set to 0 or delete line for single app.

Interval 15 interval 2 days Set to 0 or delete line for single app.

Interval 16 interval 2 days Set to 0 or delete line for single app.

Interval 17 interval 2 days Set to 0 or delete line for single app.

Interval 18 interval 2 days Set to 0 or delete line for single app.

Interval 19 interval 2 days Set to 0 or delete line for single app.

Interval 20 interval 2 days Set to 0 or delete line for single app.

Interval 21 interval 2 days Set to 0 or delete line for single app.

Interval 22 interval 2 days Set to 0 or delete line for single app.

Interval 23 interval 2 days Set to 0 or delete line for single app.

Interval 24 interval 2 days Set to 0 or delete line for single app.

Interval 25 interval 2 days Set to 0 or delete line for single app.

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR IR

Flag for runoff calc. RUNOFF total none, monthly or total(average of
entire run)

stored as MSSoyIRJA1.out

Chemical: Imidacloprid

PRZM environment: MSsoybeanSTD.txt modified Wedday, 23 August 2006 at
10:35:02

EXAMS environment: ir298.exv modified Thuday, 29 August 2002 at 14:34:12

Metfile: w03940.dvf modified Wedday, 3 July 2002 at 08:05:46

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.7086 0.6894 0.6482 0.5944 0.5394 0.2073

1962 0.6536 0.6358 0.5677 0.458 0.4439 0.2073

1963 0.4843 0.4715 0.4283 0.3291 0.2914 0.1668

1964 0.9896 0.9679 0.8777 0.7881 0.7416 0.3319

1965 1.742 1.694 1.512 1.2 1.021 0.3793

1966 1.469 1.446 1.324 1.083 0.9331 0.3959

1967 0.991 0.9637 0.888 0.7251 0.6337 0.2743

1968 0.6374 0.6227 0.5635 0.4736 0.413 0.1921

1969 1.647 1.604 1.438 1.13 0.9739 0.3572

1970 0.8212 0.7988 0.744 0.6615 0.6149 0.2977

1971 1.442 1.403 1.251 0.9863 0.8511 0.3701

1972 0.447 0.4348 0.388 0.3623 0.3416 0.2101

1973 0.4228 0.4112 0.3768 0.3021 0.2658 0.1196

1974 0.8088 0.7866 0.7146 0.6053 0.5305 0.193

1975 2.528 2.479 2.325 2.084 1.839 0.652

1976 1.156 1.131 1.059 0.8501 0.7304 0.3659

1977 0.9473 0.9214 0.8269 0.6913 0.6339 0.293

1978 0.9582 0.9324 0.8721 0.7037 0.6113 0.2588

1979 1.645 1.601 1.438 1.378 1.297 0.5601

1980 0.4391 0.4293 0.391 0.3205 0.2787 0.2001

1981 0.6493 0.6316 0.5728 0.4647 0.4044 0.1697

1982 1.549 1.518 1.381 1.106 1.112 0.4815

1983 0.984 0.9624 0.8962 0.7762 0.6899 0.3516

1984 1.007 0.9853 0.8994 0.7376 0.6846 0.3016

1985 1.861 1.812 1.634 1.322 1.136 0.4277

1986 0.7098 0.6905 0.6166 0.5777 0.5274 0.2891

1987 0.5322 0.5204 0.4858 0.3991 0.3434 0.1995

1988 0.877 0.8583 0.7756 0.6856 0.6275 0.273

1989 0.6712 0.6532 0.5846 0.5091 0.4635 0.2199

1990 0.7854 0.7637 0.701 0.576 0.4966 0.2047

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 2.528 2.479 2.325 2.084 1.839 0.652

0.0645161290322581 1.861 1.812 1.634 1.378 1.297 0.5601

0.0967741935483871 1.742 1.694 1.512 1.322 1.136 0.4815

0.129032258064516 1.647 1.604 1.438 1.2 1.112 0.4277

0.161290322580645 1.645 1.601 1.438 1.13 1.021 0.3959

0.193548387096774 1.549 1.518 1.381 1.106 0.9739 0.3793

0.225806451612903 1.469 1.446 1.324 1.083 0.9331 0.3701

0.258064516129032 1.442 1.403 1.251 0.9863 0.8511 0.3659

0.290322580645161 1.156 1.131 1.059 0.8501 0.7416 0.3572

0.32258064516129 1.007 0.9853 0.8994 0.7881 0.7304 0.3516

0.354838709677419 0.991 0.9679 0.8962 0.7762 0.6899 0.3319

0.387096774193548 0.9896 0.9637 0.888 0.7376 0.6846 0.3016

0.419354838709677 0.984 0.9624 0.8777 0.7251 0.6339 0.2977

0.451612903225806 0.9582 0.9324 0.8721 0.7037 0.6337 0.293

0.483870967741936 0.9473 0.9214 0.8269 0.6913 0.6275 0.2891

0.516129032258065 0.877 0.8583 0.7756 0.6856 0.6149 0.2743

0.548387096774194 0.8212 0.7988 0.744 0.6615 0.6113 0.273

0.580645161290323 0.8088 0.7866 0.7146 0.6053 0.5394 0.2588

0.612903225806452 0.7854 0.7637 0.701 0.5944 0.5305 0.2199

0.645161290322581 0.7098 0.6905 0.6482 0.5777 0.5274 0.2101

0.67741935483871 0.7086 0.6894 0.6166 0.576 0.4966 0.2073

0.709677419354839 0.6712 0.6532 0.5846 0.5091 0.4635 0.2073

0.741935483870968 0.6536 0.6358 0.5728 0.4736 0.4439 0.2047

0.774193548387097 0.6493 0.6316 0.5677 0.4647 0.413 0.2001

0.806451612903226 0.6374 0.6227 0.5635 0.458 0.4044 0.1995

0.838709677419355 0.5322 0.5204 0.4858 0.3991 0.3434 0.193

0.870967741935484 0.4843 0.4715 0.4283 0.3623 0.3416 0.1921

0.903225806451613 0.447 0.4348 0.391 0.3291 0.2914 0.1697

0.935483870967742 0.4391 0.4293 0.388 0.3205 0.2787 0.1668

0.967741935483871 0.4228 0.4112 0.3768 0.3021 0.2658 0.1196

0.1 1.7325 1.685 1.5046 1.3098 1.1336 0.47612

Average of yearly averages: 0.29836

Inputs generated by pe4.pl - 8-August-2003

Data used for this run:

Output File: MSSoyIRJA1

Metfile: w03940.dvf

PRZM scenario: MSsoybeanSTD.txt

EXAMS environment file: ir298.exv

Chemical Name: Imidacloprid

Description Variable Name Value Units Comments

Molecular weight mwt 255.6633 g/mol

Henry\'s Law Const. henry 4.0e-12 atm-m\^3/mol

Vapor Pressure vapr 1.5e-9 torr

Solubility sol 580 mg/L

Kd Kd mg/L

Koc Koc 178 mg/L

Photolysis half-life kdp 39 days Half-life

Aerobic Aquatic Metabolism kbacw 1040 days Halfife

Anaerobic Aquatic Metabolism kbacs 81 days Halfife

Aerobic Soil Metabolism asm 520 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0.0 cm

Application Rate: TAPP .0025 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.064 fraction of application rate applied to pond

Application Date Date 05-07 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 2 days Set to 0 or delete line for single app.

Interval 2 interval 2 days Set to 0 or delete line for single app.

Interval 3 interval 2 days Set to 0 or delete line for single app.

Interval 4 interval 2 days Set to 0 or delete line for single app.

Interval 5 interval 2 days Set to 0 or delete line for single app.

Interval 6 interval 2 days Set to 0 or delete line for single app.

Interval 7 interval 2 days Set to 0 or delete line for single app.

Interval 8 interval 2 days Set to 0 or delete line for single app.

Interval 9 interval 2 days Set to 0 or delete line for single app.

Interval 10 interval 2 days Set to 0 or delete line for single app.

Interval 11 interval 2 days Set to 0 or delete line for single app.

Interval 12 interval 2 days Set to 0 or delete line for single app.

Interval 13 interval 2 days Set to 0 or delete line for single app.

Interval 14 interval 2 days Set to 0 or delete line for single app.

Interval 15 interval 2 days Set to 0 or delete line for single app.

Interval 16 interval 2 days Set to 0 or delete line for single app.

Interval 17 interval 2 days Set to 0 or delete line for single app.

Interval 18 interval 2 days Set to 0 or delete line for single app.

Interval 19 interval 2 days Set to 0 or delete line for single app.

Interval 20 interval 2 days Set to 0 or delete line for single app.

Interval 21 interval 2 days Set to 0 or delete line for single app.

Interval 22 interval 2 days Set to 0 or delete line for single app.

Interval 23 interval 2 days Set to 0 or delete line for single app.

Interval 24 interval 2 days Set to 0 or delete line for single app.

Interval 25 interval 2 days Set to 0 or delete line for single app.

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR IR

Flag for runoff calc. RUNOFF total none, monthly or total(average of
entire run)

stored as MSSoyIRJA2.out

Chemical: Imidacloprid

PRZM environment: MSsoybeanSTD.txt modified Wedday, 23 August 2006 at
10:35:02

EXAMS environment: ir298.exv modified Thuday, 29 August 2002 at 14:34:12

Metfile: w03940.dvf modified Wedday, 3 July 2002 at 08:05:46

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.7187 0.6992 0.653 0.5977 0.5422 0.2106

1962 0.6631 0.6451 0.5759 0.4647 0.4501 0.2121

1963 0.5004 0.4871 0.4425 0.3283 0.2913 0.1687

1964 1.004 0.9787 0.889 0.8038 0.756 0.3371

1965 1.816 1.766 1.576 1.251 1.064 0.3931

1966 1.332 1.308 1.202 0.9915 0.8581 0.3773

1967 1.021 0.9926 0.9154 0.7483 0.6546 0.2745

1968 0.6319 0.6201 0.5641 0.4758 0.4161 0.1954

1969 1.563 1.525 1.37 1.077 0.9307 0.3469

1970 0.8707 0.8468 0.7934 0.7109 0.6517 0.3099

1971 1.475 1.435 1.28 1.008 0.8705 0.3741

1972 0.4483 0.436 0.3891 0.3645 0.3411 0.2125

1973 0.4314 0.4195 0.3846 0.3085 0.2702 0.1213

1974 0.8293 0.8065 0.7327 0.6201 0.5436 0.1973

1975 2.348 2.293 2.16 1.938 1.719 0.619

1976 1.146 1.121 1.05 0.8427 0.7239 0.3542

1977 0.9648 0.9384 0.8422 0.7066 0.6331 0.2934

1978 0.9762 0.95 0.8882 0.7167 0.6226 0.2601

1979 1.613 1.57 1.411 1.346 1.27 0.5517

1980 0.4507 0.4406 0.4012 0.3287 0.2857 0.205

1981 0.668 0.6497 0.5894 0.4786 0.4168 0.174

1982 1.651 1.617 1.472 1.178 1.179 0.5063

1983 1.008 0.9827 0.915 0.7929 0.7046 0.3639

1984 1.016 0.9912 0.905 0.7432 0.6924 0.3034

1985 1.761 1.718 1.552 1.264 1.09 0.4133

1986 0.7212 0.7016 0.6263 0.5929 0.5333 0.287

1987 0.5396 0.5304 0.4958 0.4081 0.3512 0.2052

1988 0.8991 0.8769 0.7947 0.707 0.6496 0.2806

1989 0.684 0.6657 0.5957 0.5181 0.472 0.2242

1990 0.8074 0.7851 0.7205 0.5922 0.5106 0.2094

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 2.348 2.293 2.16 1.938 1.719 0.619

0.0645161290322581 1.816 1.766 1.576 1.346 1.27 0.5517

0.0967741935483871 1.761 1.718 1.552 1.264 1.179 0.5063

0.129032258064516 1.651 1.617 1.472 1.251 1.09 0.4133

0.161290322580645 1.613 1.57 1.411 1.178 1.064 0.3931

0.193548387096774 1.563 1.525 1.37 1.077 0.9307 0.3773

0.225806451612903 1.475 1.435 1.28 1.008 0.8705 0.3741

0.258064516129032 1.332 1.308 1.202 0.9915 0.8581 0.3639

0.290322580645161 1.146 1.121 1.05 0.8427 0.756 0.3542

0.32258064516129 1.021 0.9926 0.9154 0.8038 0.7239 0.3469

0.354838709677419 1.016 0.9912 0.915 0.7929 0.7046 0.3371

0.387096774193548 1.008 0.9827 0.905 0.7483 0.6924 0.3099

0.419354838709677 1.004 0.9787 0.889 0.7432 0.6546 0.3034

0.451612903225806 0.9762 0.95 0.8882 0.7167 0.6517 0.2934

0.483870967741936 0.9648 0.9384 0.8422 0.7109 0.6496 0.287

0.516129032258065 0.8991 0.8769 0.7947 0.707 0.6331 0.2806

0.548387096774194 0.8707 0.8468 0.7934 0.7066 0.6226 0.2745

0.580645161290323 0.8293 0.8065 0.7327 0.6201 0.5436 0.2601

0.612903225806452 0.8074 0.7851 0.7205 0.5977 0.5422 0.2242

0.645161290322581 0.7212 0.7016 0.653 0.5929 0.5333 0.2125

0.67741935483871 0.7187 0.6992 0.6263 0.5922 0.5106 0.2121

0.709677419354839 0.684 0.6657 0.5957 0.5181 0.472 0.2106

0.741935483870968 0.668 0.6497 0.5894 0.4786 0.4501 0.2094

0.774193548387097 0.6631 0.6451 0.5759 0.4758 0.4168 0.2052

0.806451612903226 0.6319 0.6201 0.5641 0.4647 0.4161 0.205

0.838709677419355 0.5396 0.5304 0.4958 0.4081 0.3512 0.1973

0.870967741935484 0.5004 0.4871 0.4425 0.3645 0.3411 0.1954

0.903225806451613 0.4507 0.4406 0.4012 0.3287 0.2913 0.174

0.935483870967742 0.4483 0.436 0.3891 0.3283 0.2857 0.1687

0.967741935483871 0.4314 0.4195 0.3846 0.3085 0.2702 0.1213

0.1 1.75 1.7079 1.544 1.2627 1.1701 0.497

Average of yearly averages: 0.29938

Inputs generated by pe4.pl - 8-August-2003

Data used for this run:

Output File: MSSoyIRJA2

Metfile: w03940.dvf

PRZM scenario: MSsoybeanSTD.txt

EXAMS environment file: ir298.exv

Chemical Name: Imidacloprid

Description Variable Name Value Units Comments

Molecular weight mwt 255.6633 g/mol

Henry\'s Law Const. henry 4.0e-12 atm-m\^3/mol

Vapor Pressure vapr 1.5e-9 torr

Solubility sol 580 mg/L

Kd Kd mg/L

Koc Koc 178 mg/L

Photolysis half-life kdp 39 days Half-life

Aerobic Aquatic Metabolism kbacw 1040 days Halfife

Anaerobic Aquatic Metabolism kbacs 81 days Halfife

Aerobic Soil Metabolism asm 520 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0.0 cm

Application Rate: TAPP .0025 kg/ha

Application Efficiency: APPEFF 0.99 fraction

Spray Drift DRFT 0.064 fraction of application rate applied to pond

Application Date Date 06-07 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 2 days Set to 0 or delete line for single app.

Interval 2 interval 2 days Set to 0 or delete line for single app.

Interval 3 interval 2 days Set to 0 or delete line for single app.

Interval 4 interval 2 days Set to 0 or delete line for single app.

Interval 5 interval 2 days Set to 0 or delete line for single app.

Interval 6 interval 2 days Set to 0 or delete line for single app.

Interval 7 interval 2 days Set to 0 or delete line for single app.

Interval 8 interval 2 days Set to 0 or delete line for single app.

Interval 9 interval 2 days Set to 0 or delete line for single app.

Interval 10 interval 2 days Set to 0 or delete line for single app.

Interval 11 interval 2 days Set to 0 or delete line for single app.

Interval 12 interval 2 days Set to 0 or delete line for single app.

Interval 13 interval 2 days Set to 0 or delete line for single app.

Interval 14 interval 2 days Set to 0 or delete line for single app.

Interval 15 interval 2 days Set to 0 or delete line for single app.

Interval 16 interval 2 days Set to 0 or delete line for single app.

Interval 17 interval 2 days Set to 0 or delete line for single app.

Interval 18 interval 2 days Set to 0 or delete line for single app.

Interval 19 interval 2 days Set to 0 or delete line for single app.

Interval 20 interval 2 days Set to 0 or delete line for single app.

Interval 21 interval 2 days Set to 0 or delete line for single app.

Interval 22 interval 2 days Set to 0 or delete line for single app.

Interval 23 interval 2 days Set to 0 or delete line for single app.

Interval 24 interval 2 days Set to 0 or delete line for single app.

Interval 25 interval 2 days Set to 0 or delete line for single app.

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR IR

Flag for runoff calc. RUNOFF total none, monthly or total(average of
entire run)

[^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.