**DRAFT ECOLOGICAL HAZARD AND ENVIRONMENTAL**

**RISK ASSESSMENT CHAPTER**

**Alkyl Dimethyl Benzyl Ammonium Chloride (ADBAC)**

**PC Code 069105**

**CASE No.:**

**04/10/2006**

**Richard C. Petrie**

**Kathryn Montague**

**Antimicrobials Division**

**Office of Pesticide Programs**

**U.S. Environmental Protection Agency**

**1200 Pennsylvania Avenue, NW**

**Washington, DC 20460**

Table of Contents

1\. Ecological Toxicity Data . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

A. Toxicity to Terrestrial Animals . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . 4

1\. Birds, Acute and Subacute . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 4

2\. Mammals, Acute and Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . 5

B. Toxicity to Aquatic Animals . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . 5

1\. Freshwater Fish, Acute . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 6

2\. Freshwater Invertebrates, Acute . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . 8

3\. Estuarine and Marine Organisms, Acute . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . 9

4\. Aquatic Organisms, Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . 10

C. Toxicity to Plants . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

II\. Risk Assessment and Risk Characterization . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .15

A. Environmental Fate Assessment Summary . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . .. . . . . 18

B. Environmental Exposure Assessment . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . .. . . . . . . 18

C. Endangered Species Considerations . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . .26

III\. Confirmatory Data Required. . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .. . . . . . . . . 28

IV\. Label Hazard Statements for Terrestrial and Aquatic Organisms. . .
. . . . . . . . . . . . . . . . . .28

V. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

**Ecological Hazard and Environment Risk Assessment**

**Alkyl Dimethyl Benzyl Ammonium Chloride (ADBAC)**

Alkyl dimethyl benzyl ammonium chloride (ADBAC) (PC Code 069105) is a
surface-active (surfactant) chemical, which is effective against a broad
spectrum of microorganisms. It is currently registered as a
bactericidal, fungicidal, and algaecidal agent. It is used at a variety
of indoor and aquatic sites including agricultural premises and
equipment, food handling, commercial, industrial and institutional
settings, residential areas or areas of public access, pets and kennels,
medical facilities, swimming pools, aquatic areas, and industrial water
systems. ADBAC is also used as a wood preservative (non-aquatic sites
only) and agriculturally on ornamental plants, shrubs, and vines. The
Manufacturing Use Products (MUPs) of ADBAC are available in two grades,
a 50% and 80% solution.

**I. Ecological Toxicity Data**

In addition to estimating risks to human health, the Agency also
assesses risks to terrestrial animals, aquatic organisms, and plants.
The toxicity endpoints presented below are based on the results of
ecotoxicity studies submitted to EPA to meet the Agency=s data
requirements for the uses of ADBAC, as well as review of the open
literature.

The toxicity of ADBAC is dependent upon its bioavailability. Due to its
propensity for binding to organic material, the toxicity of ADBAC may be
mitigated in natural environments.

> **A. Toxicity to Terrestrial Animals**
>
> **(1) Birds, Acute and Subacute**

In order to establish the toxicity of ADBAC to avian species for indoor,
aquatic industrial, and wood preservative uses, the Agency requires an
acute oral toxicity study using the technical grade active ingredient
(TGAI). The preferred-test species is either mallard duck (a waterfowl)
or bobwhite quail (an upland game bird). The results of one acute oral
toxicity study, submitted for ADBAC, are provided in the following table
(Table 1).

**Table 1. Acute Oral Toxicity of ADBAC to Birds**

+-----------+----------+----------+---------+---------------+--------+
| **        | **Che    | **En     | **T     | **Satisfies   | *      |
| Species** | mical,** | dpoint** | oxicity | Guidelines/** | *Refer |
|           |          |          | Cat     |               | ence** |
|           | **%      | **(      | egory** | **Comments**  |        |
|           | Active   | mg/kg)** |         |               | *      |
|           | Ingr     |          |         |               | *(MRID |
|           | edient** |          |         |               | No.)** |
|           |          |          |         |               |        |
|           | **       |          |         |               |        |
|           | (a.i.)** |          |         |               |        |
|           |          |          |         |               |        |
|           | **       |          |         |               |        |
|           | Tested** |          |         |               |        |
+-----------+----------+----------+---------+---------------+--------+
| Bobwhite  | ADBAC    | LD~50~ = | Mod     | Yes           | 428    |
| quail     | 80%      | 136      | erately |               | 859-01 |
|           |          |          | toxic   | \$ core study |        |
| (*Colinus |          | NOAEC =  |         |               |        |
| vir       |          | 62.5     |         | \$ 14-day     |        |
| ginianus* |          |          |         | test duration |        |
|           |          | (a.i.)   |         |               |        |
|           |          |          |         | \$ 17 weeks   |        |
|           |          |          |         | of age        |        |
+-----------+----------+----------+---------+---------------+--------+

The results from the one core study indicate that ADBAC is moderately
toxic to avian species on an acute oral basis. Study 428859-01 fulfills
guideline requirement 71-1/OPPTS 850.2100.

A subacute dietary study using the TGAI may be required on a
case-by-case basis depending on the results of lower-tier ecological
studies and pertinent environmental fate characteristics in order to
establish the toxicity of a chemical to avian species. This testing was
not required for ADBAC.

> **(2) Mammals, Acute and Chronic Toxicity**

Wild mammal testing is not required by the Agency. In most cases, rat
toxicity values obtained from studies conducted to support data
requirements for human health risk assessments substitute for wild
mammal testing.

To summarize the human toxicology chapter of this RED, In an acute oral
toxicity study (MRID 45109204), the acute oral LD~50~ of ADBAC (82.26%
a.i.) was determined to be 304.5 mg/kg (both sexes combined) and was
assigned Toxicity Category II. In an acute dermal toxicity study (MRID
45109202), the acute dermal LD~50~ of ADBAC (82.26% a.i.) was determined
to be 930 mg/kg (both sexes combined) and was assigned Toxicity Category
II. In an acute inhalation toxicity study (MRID 44885201), the acute
LC~50~ of ADBAC (82.26% a.i.) was determined to be 0.054 \< LC~50~ \<
0.51 mg/L and was assigned a Toxicity Category II. The primary eye
irritation study was waived and assigned a Toxicity Category I for
technical grade ADBAC (80% a.i). For primary dermal irritation (MRID
45109201), ADBAC (82.26% a.i.) was corrosive to rabbits (Toxicity
Category I). In a dermal sensitization study (MRID 45109203), ADBAC
(82.26% a.i.) was not a sensitizer to guinea pigs. In a photoallergy
(light) sensitization study (MRID 40958501 and MRID 44825002), ADBAC
(80% a.i.) was not a photosensitizer.

In a subchronic oral toxicity study in rats (MRID 40746601), ADBAC was
found to have a low order of toxicity, in that manifestations of
toxicity were non-specific (decreased body weight gain, food
consumption), and **occurred** at relatively high doses (LOAEL of 62
mg/kg/day in males, 308 mg/kg/day in females). This result was also
observed in chronic toxicity studies in rats and mice (MRIDs 41947501
and 41765201), where effects were also non -specific in nature
(decreased body weight gain and food consumption), and occurred at
relatively high doses. In a 21-day dermal toxicity study in guinea pigs
(MRID 41105801), no significant systemic effects were observed using a
chemical mixture of 4% ADBAC/6% DDAC, but denuding of the epidermal
layer was observed at the highest tested, 1000 mg/kg/day. In a 90-day
dermal toxicity study in rats (MRID 41499601) using technical grade
ADBAC , dermal applications of ADBAC (81.09% a.i.) to rats did not
elicit systemic or dermal toxicity up to the highest dose tested, 20
mg/kg/day, before dermal irritation became significant.

ADBAC has been examined for effects on development of the mammalian
fetus and effects on reproductive function. In developmental studies
with rats (range-finding MRID 42645101 and main study MRID 42351501) and
rabbits (range-finding MRID 42734401 and main study MRID 42392801),
developing fetuses showed no increased sensitivity to the toxicity of
ADBAC in relation to adult animals. In a 2-generation reproductive
toxicity study (MRID 41385001), effects on rat pups were observed in the
absence of maternal toxicity, raising some concern for the effects of
ADBAC on reproductive function. However, the effects observed were
non-specific (decreased pup body weight and weight gain during
lactation), and there were no effects of ADBAC on reproductive indices.

In a chronic toxicity study in dogs (MRID 43221101), groups of 4 male
and female beagle dogs per group received either 0, 120, 400, or 1200
ppm (0, 3.79, 13.1, or 33.8 mg/kg/day in males and 0, 3.67, 14.6, or
38.6 mg/kg/day in females) alkyl dimethyl benzyl ammonium chloride
\[ADBAC, 80% a.i.\] as a direct dietary admix for one year. Systemic
toxicity was observed at 13.1 mg/kg/day in males and 14.6 mg/kg/day in
females reduced body weight gain (approximately 10% reduction) after 52
weeks of exposure. Food consumption was decreased in the 1200 ppm males
and females for the entire study period (approximately 15% reduction in
males and 5% reduction in females). Based on the data in this study, the
Systemic Toxicity NOAEL was 120 ppm (3.79 mg/kg/day in males, 3.67
mg/kg/day in females) and the LOAEL was 400 ppm (13.1 mg/kg/day in
males, 14.6 mg/kg/day in females) based on reduced body weight gain.

ADBAC has been tested for carcinogenicity in long term studies with both
rats (MRID 41947501) and mice (MRID 41765201). In both studies, tested
to adequate dose levels, ADBAC was negative for induction of tumors in
both species. This result is supported by results of testing in a
battery of mutagenicity studies, including an HGPRT/CHO for ward
mutation assay (MRID 41012701), an in vivo bone marrow chromosome
aberration assay (MRID 40311101, supplement MRID 43037701), and an
unscheduled DNA synthesis (UDS) assay (MRIDs 42290801 and 42290802),
which show ADBAC to be negative for mutagenic effects.

The metabolism of ADBAC was investigated in MRID 41087701. The majority
of administered radioactive ADBAC is eliminated in feces from oral
administration. Intravenous administration also shows elimination of a
significant proportion of ADBAC in feces, indicating elimination through
the bile. Tissue retention of orally administered radioactivity is
negligible.

Refer to the human toxicology chapter of this RED for additional
mammalian toxicity data.

> **B. Toxicity to Aquatic Animals**

The Agency requested that aquatic toxicity studies be conducted with
ADBAC since, under typical use conditions, it is introduced into the
aquatic environment.

> **(1) Freshwater Fish, Acute**

In order to establish the acute toxicity of ADBAC to freshwater fish,
the Agency requires freshwater fish toxicity studies using the TGAI. The
preferred test species are rainbow trout (a coldwater fish) and bluegill
sunfish (a warmwater fish). Results of freshwater fish acute studies,
submitted for ADBAC and obtained from the open literature, are presented
in Table 2.

**Table 2. Acute Toxicity of ADBAC to Freshwater Fish**

+-----------+--------+-----------+----------+---------------+--------+
| **        | *      | **E       | **       | **Satisfies   | *      |
| Species** | *Chemi | ndpoint** | Toxicity | Guidelines/** | *Refer |
|           | cal,** |           | Ca       |               | ence** |
|           |        | *         | tegory** | **Comments**  |        |
|           | **%    | *(mg/L)** |          |               | *      |
|           | Active |           |          |               | *(MRID |
|           | Ingred |           |          |               | No.)** |
|           | ient** |           |          |               |        |
|           |        |           |          |               |        |
|           | **(a   |           |          |               |        |
|           | .i.)** |           |          |               |        |
|           |        |           |          |               |        |
|           | **Te   |           |          |               |        |
|           | sted** |           |          |               |        |
+===========+========+===========+==========+===============+========+
| Bluegill  | ADBAC  | LC~50~ =  | Highly   | Yes           | 419    |
| sunfish   | 30%\*  | 0.515     | toxic    |               | 472-01 |
| (*Lepomis |        |           |          | \$ core study |        |
| macr      |        | NOAEC =   |          |               |        |
| ochirus)* |        | 0.456     |          | \$ 96-hr test |        |
|           |        |           |          | duration      |        |
|           |        | (a.i.)    |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | s             |        |
|           |        |           |          | tatic-renewal |        |
|           |        |           |          | test system   |        |
+-----------+--------+-----------+----------+---------------+--------+
| Fathead   | ADBAC  | LC~50~ =  | Highly   | Yes           | 437    |
| minnow    |        | 0.28      | toxic    |               | 401-03 |
| (*P       | 80%    |           |          | \$ core study |        |
| imephales |        | NOAEC =   |          |               |        |
| p         |        | ND        |          | \$ 96-hr test |        |
| romelas)* |        |           |          | duration      |        |
|           |        | (a.i.)    |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | s             |        |
|           |        |           |          | tatic-renewal |        |
|           |        |           |          | test system   |        |
+-----------+--------+-----------+----------+---------------+--------+
| Fathead   | ADBAC  | LC~50~ =  | Mo       | No            | 437    |
| minnow    |        | 1.4       | derately |               | 401-01 |
| *(P       | 80%    |           | toxic    | \$            |        |
| imephales |        | NOAEC =   |          | supplemental  |        |
| p         |        | 0.99      |          | study         |        |
| romelas)* |        |           |          |               |        |
|           |        | (a.i.)    |          | \$ 96-hr test |        |
|           |        |           |          | duration      |        |
|           |        |           |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | s             |        |
|           |        |           |          | tatic-renewal |        |
|           |        |           |          | test system   |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ deviations |        |
|           |        |           |          | from          |        |
|           |        |           |          | guideline     |        |
|           |        |           |          | include       |        |
|           |        |           |          | addition of   |        |
|           |        |           |          | 20 mg/L humic |        |
|           |        |           |          | acid to       |        |
|           |        |           |          | dilution      |        |
|           |        |           |          | water         |        |
+-----------+--------+-----------+----------+---------------+--------+
| Fathead   | ADBAC  | LC~50~ =  | Highly   | No            | 437    |
| minnow    |        | 0.77      | toxic    |               | 401-02 |
| *(P       | 80%    |           |          | \$            |        |
| imephales |        | NOAEC =   |          | supplemental  |        |
| p         |        | 0.53      |          | study         |        |
| romelas)* |        |           |          |               |        |
|           |        | (a.i.)    |          | \$ 96-hr test |        |
|           |        |           |          | duration      |        |
|           |        |           |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | s             |        |
|           |        |           |          | tatic-renewal |        |
|           |        |           |          | test system   |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ deviations |        |
|           |        |           |          | from          |        |
|           |        |           |          | guideline     |        |
|           |        |           |          | include       |        |
|           |        |           |          | addition of   |        |
|           |        |           |          | 10 mg/L humic |        |
|           |        |           |          | acid to       |        |
|           |        |           |          | dilution      |        |
|           |        |           |          | water and not |        |
|           |        |           |          | preferred     |        |
|           |        |           |          | test species  |        |
+-----------+--------+-----------+----------+---------------+--------+
| Fathead   | ADBAC  | LC~50~ =  | High ly  | No            | Dobbs, |
| minnow    |        | 0.36      | toxic    |               | M.G.   |
| (*P       | 50%    |           |          | \$            | et al. |
| imephales |        | (a.i.)    |          | supplemental  |        |
| p         |        |           |          | study         |        |
| romelas*) |        |           |          |               |        |
|           |        |           |          | \$ open       |        |
|           |        |           |          | literature    |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ 96-hr test |        |
|           |        |           |          | duration      |        |
|           |        |           |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | flow-through  |        |
|           |        |           |          | test system   |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ deviations |        |
|           |        |           |          | from          |        |
|           |        |           |          | guideline     |        |
|           |        |           |          | include lack  |        |
|           |        |           |          | of detailed   |        |
|           |        |           |          | information   |        |
+-----------+--------+-----------+----------+---------------+--------+
| Rainbow   | ADBAC  | LC~50~ =  | Highly   | Yes           | 419    |
| Trout     | 3      | 0.923     | toxic    |               | 472-02 |
| (*Onc     | 0%[^1] |           |          | \$ core study |        |
| orhynchus |        | NOAEC =   |          |               |        |
| mykiss)*  |        | 0.619     |          | \$ 96-hr test |        |
|           |        |           |          | duration      |        |
|           |        | (a.i.)    |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | s             |        |
|           |        |           |          | tatic-renewal |        |
|           |        |           |          | test system   |        |
+-----------+--------+-----------+----------+---------------+--------+
| Rainbow   | ADBAC  | LC~50~ =  | Highly/  | No            | Dobbs, |
| Trout     |        | 1.01      | mo       |               | M.G.   |
| (O*nc     | 50%    |           | derately | \$            | et al. |
| orhynchus |        | (a.i.)    | toxic    | supplemental  |        |
| mykiss*)  |        |           |          | study         |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ open       |        |
|           |        |           |          | literature    |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ 96-hr test |        |
|           |        |           |          | duration      |        |
|           |        |           |          |               |        |
|           |        |           |          | \$            |        |
|           |        |           |          | flow-through  |        |
|           |        |           |          | test system   |        |
|           |        |           |          |               |        |
|           |        |           |          | \$ deviations |        |
|           |        |           |          | from          |        |
|           |        |           |          | guideline     |        |
|           |        |           |          | include lack  |        |
|           |        |           |          | of detailed   |        |
|           |        |           |          | information   |        |
+-----------+--------+-----------+----------+---------------+--------+

The results indicate that ADBAC is highly to moderately toxic to
warmwater fish and coldwater fish on an acute basis. Studies 419472-01
and 419470-02 fulfill guideline requirements 72‑1a,c/OPPTS 850.1075.

**(2)** **Freshwater Invertebrates, Acute**

The Agency requires a freshwater aquatic invertebrate study using the
TGAI to establish the acute toxicity to freshwater invertebrates. The
preferred test species is *Daphnia magna*. Results of two studies,
submitted for ADBAC and obtained from the open literature, are provided
in the following table (Table 3).

**Table 3. Acute Toxicity of ADBAC to Freshwater Invertebrates**

+------------+----------+----------+--------+--------------+--------+
| *          | **Che    | **En     | **To   | **Satisfies  | *      |
| *Species** | mical,** | dpoint** | xicity | G            | *Refer |
|            |          |          | Cate   | uidelines/** | ence** |
|            | **%      | **       | gory** |              |        |
|            | Active   | (mg/L)** |        | **Comments** | *      |
|            | Ingr     |          |        |              | *(MRID |
|            | edient** |          |        |              | No.)** |
|            |          |          |        |              |        |
|            | **       |          |        |              |        |
|            | (a.i.)** |          |        |              |        |
|            |          |          |        |              |        |
|            | **       |          |        |              |        |
|            | Tested** |          |        |              |        |
+============+==========+==========+========+==============+========+
| Waterflea  | ADBAC    | EC~50~ = | Very   | Yes          | 419    |
| (*Daphnia  |          | 0.0059   | highly |              | 472-03 |
| magna)*    | 30%[^2]  |          | toxic  | \$ core      |        |
|            |          | NOAEC =  |        | study        |        |
|            |          | ND       |        |              |        |
|            |          | (a.i.)   |        | \$ 48-hr     |        |
|            |          |          |        | test         |        |
|            |          |          |        | duration     |        |
|            |          |          |        |              |        |
|            |          |          |        | \$           |        |
|            |          |          |        | st           |        |
|            |          |          |        | atic-renewal |        |
|            |          |          |        | test system  |        |
+------------+----------+----------+--------+--------------+--------+
| Waterflea  | ADBAC    | LC~50~ = | Very   | No           | Dobbs, |
| (*Daphnia  |          | 0.02     | highly |              | M.G.,  |
| magna)*    | 50%      | (a.i.)   | toxic  | \$           | et al. |
|            |          |          |        | supplemental |        |
|            |          |          |        | study        |        |
|            |          |          |        |              |        |
|            |          |          |        | \$ open      |        |
|            |          |          |        | literature   |        |
|            |          |          |        |              |        |
|            |          |          |        | \$ 48-hr     |        |
|            |          |          |        | test         |        |
|            |          |          |        | duration     |        |
|            |          |          |        |              |        |
|            |          |          |        | \$           |        |
|            |          |          |        | flow-through |        |
|            |          |          |        | test system  |        |
|            |          |          |        |              |        |
|            |          |          |        | \$           |        |
|            |          |          |        | deviations   |        |
|            |          |          |        | from         |        |
|            |          |          |        | guideline    |        |
|            |          |          |        | include lack |        |
|            |          |          |        | of detailed  |        |
|            |          |          |        | information  |        |
+------------+----------+----------+--------+--------------+--------+

Results of the studies indicate that ADBAC is very highly toxic to
freshwater invertebrates. Study 419472-03 fulfills guideline requirement
72-2a, OPPTS 850.1010.

> **(3) Estuarine and Marine Organisms, Acute**

Acute toxicity testing with estuarine and marine organisms using the
TGAI is required when the end-use product is intended for direct
application to the marine/estuarine environment or effluent containing
the active ingredient is expected to reach this environment. The
preferred fish test species is sheepshead minnow. The preferred
invertebrate test species are mysid shrimp and eastern oysters. This
testing is required for ADBAC based on the chemical=s use in aquatic
sites such as pulp and paper mills, once-through cooling towers, oil
field recovery systems and as a wood preservative. Results of toxicity
studies, submitted for ADBAC and obtained from the open literature, are
presented in Table 4.

**Table 4. Acute Toxicity of ADBAC to Estuarine and Marine Organisms**

+-----------+--------+------------+--------+----------------+---------+
| **        | *      | **         | **To   | **Satisfies    | **Refe  |
| Species** | *Chemi | Endpoint** | xicity | Guidelines/**  | rence** |
|           | cal,** |            | Cate   |                |         |
|           |        | **(mg/L)** | gory** | **Comments**   | **(MRID |
|           | **%    |            |        |                | No.)**  |
|           | Active |            |        |                |         |
|           | Ingred |            |        |                |         |
|           | ient** |            |        |                |         |
|           |        |            |        |                |         |
|           | **(a   |            |        |                |         |
|           | .i.)** |            |        |                |         |
|           |        |            |        |                |         |
|           | **Te   |            |        |                |         |
|           | sted** |            |        |                |         |
+===========+========+============+========+================+=========+
| S         | ADBAC  | LC~50~ =   | Highly | Yes            | 42      |
| heepshead | 80%    | 0.86       | toxic  |                | 4795-02 |
| minnow    |        |            |        | \$ core study  |         |
| (*C       |        | NOAEC =    |        |                |         |
| yprinodon |        | 0.68       |        | \$ 96-hr test  |         |
| var       |        |            |        | duration       |         |
| iegatus*) |        | (a.i.)     |        |                |         |
|           |        |            |        | \$             |         |
|           |        |            |        | static-renewal |         |
|           |        |            |        | test system    |         |
+-----------+--------+------------+--------+----------------+---------+
| Inland    | ADBAC  | LC~50~ =   | Highly | No             | Dobbs,  |
| s         | 50%    | 0.31       | toxic  |                | M.G. et |
| ilverside |        |            |        | \$             | al.     |
| (*Menidia |        | (a.i.)     |        | supplemental   |         |
| be        |        |            |        | study          |         |
| ryllina)* |        |            |        |                |         |
|           |        |            |        | \$ open        |         |
|           |        |            |        | literature     |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ 96-hr test  |         |
|           |        |            |        | duration       |         |
|           |        |            |        |                |         |
|           |        |            |        | \$             |         |
|           |        |            |        | flow-through   |         |
|           |        |            |        | test system    |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ deviations  |         |
|           |        |            |        | from guideline |         |
|           |        |            |        | include lack   |         |
|           |        |            |        | of detailed    |         |
|           |        |            |        | information    |         |
|           |        |            |        | and species    |         |
|           |        |            |        | tested         |         |
+-----------+--------+------------+--------+----------------+---------+
| Mysid     | ADBAC  | LC~50~ =   | Very   | Yes            | 42      |
| shrimp    | 80%    | 0.092      | highly |                | 4795-01 |
| (*M       |        |            | toxic  | \$ core study  |         |
| ysidopsis |        | NOAEC =    |        |                |         |
| bahia)*   |        | 0.047      |        | \$ 96-hr test  |         |
|           |        |            |        | duration       |         |
|           |        | (a.i.)     |        |                |         |
|           |        |            |        | \$             |         |
|           |        |            |        | static-renewal |         |
|           |        |            |        | test system    |         |
+-----------+--------+------------+--------+----------------+---------+
| Mysid     | ADBAC  | LC~50~ =   | Very   | No             | Dobbs,  |
| shrimp    | 50%    | 0.08       | highly |                | M.G. et |
| (*M       |        |            | toxic  | \$             | al.     |
| ysidopsis |        | (a.i.)     |        | supplemental   |         |
| bahia*)   |        |            |        | study          |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ open        |         |
|           |        |            |        | literature     |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ 96-hr test  |         |
|           |        |            |        | duration       |         |
|           |        |            |        |                |         |
|           |        |            |        | \$             |         |
|           |        |            |        | flow-through   |         |
|           |        |            |        | test system    |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ deviations  |         |
|           |        |            |        | from guideline |         |
|           |        |            |        | include lack   |         |
|           |        |            |        | of detailed    |         |
|           |        |            |        | information    |         |
|           |        |            |        | and test       |         |
|           |        |            |        | conducted at   |         |
|           |        |            |        | higher         |         |
|           |        |            |        | temperature    |         |
|           |        |            |        | and different  |         |
|           |        |            |        | photo-period   |         |
+-----------+--------+------------+--------+----------------+---------+
| Eastern   | ADBAC  | LC~50~ =   | Very   | No             | 42      |
| oyster    |        | 0.055      | highly |                | 4795-03 |
| (*Cr      | 80%    |            | toxic  | \$             |         |
| assostrea |        | (a.i.)     |        | supplemental   |         |
| vi        |        |            |        | study          |         |
| rginica*) |        |            |        |                |         |
|           |        |            |        | \$ 48-hr test  |         |
|           |        |            |        | duration       |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ embryo      |         |
|           |        |            |        | larvae         |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ static test |         |
|           |        |            |        | system         |         |
|           |        |            |        |                |         |
|           |        |            |        | \$ deviations  |         |
|           |        |            |        | from guideline |         |
|           |        |            |        | include high   |         |
|           |        |            |        | control        |         |
|           |        |            |        | mortality      |         |
+-----------+--------+------------+--------+----------------+---------+

The results of the studies indicate that ADBAC is highly toxic to
estuarine/marine fish and very highly toxic to estuarine/marine
invertebrates on an acute basis. Two core studies MRID 424795-01 and
MRID 424795-02 fulfill guideline requirements for acute toxicity tests
for estuarine/marine fish and shrimp (72-3a,c/OPPTS 850.1035 and
850.1075). However, study 424795-03 was classified as supplemental and
does not fulfill guideline requirements (72-3b/OPPTS 850.1055). The
acute Eastern oyster embryo larvae study must be repeated.

> **(4) Aquatic Organisms, Chronic**

Chronic toxicity testing (fish early life stage, 72-4a/OPPTS 850.1400
and aquatic invertebrate life cycle, 72-4b/OPPTS 850.1300) is required
for pesticides when certain conditions of use and environmental fate
apply. The preferred freshwater fish test species is fathead minnow, but
other species may be used. The preferred freshwater invertebrate is
*Daphnia magna*. This testing is required for ADBAC. Results of these
toxicity studies, submitted for ADBAC, are presented in Table 5.

**Table 5. Chronic Toxicity of ADBAC to Freshwater Organisms**

+----------------+-----------+------------+---------------+-----------+
| **Species**    | **Ch      | **         | **Satisfies   | **Re      |
|                | emical,** | Endpoint** | Guidelines/** | ference** |
|                |           |            |               |           |
|                | **%       | **(mg/L)** | **Comments**  | **(MRID   |
|                | Active    |            |               | No.)**    |
|                | Ing       |            |               |           |
|                | redient** |            |               |           |
|                |           |            |               |           |
|                | *         |            |               |           |
|                | *(a.i.)** |            |               |           |
|                |           |            |               |           |
|                | *         |            |               |           |
|                | *Tested** |            |               |           |
+================+===========+============+===============+===========+
| Fathead Minnow | ADBAC     | LOAEC =    | Yes           | 423021-02 |
| (*Pimephales   |           | 0.0759     |               |           |
| promelas*)     | 30%       |            | \$ core study |           |
|                |           | NOAEC =    |               |           |
|                |           | 0.0322     | \$ 34-day     |           |
|                |           |            | test duration |           |
|                |           | MATC =     |               |           |
|                |           | 0.0494     | \$ early-life |           |
|                |           | (a.i.)     | stage         |           |
|                |           |            |               |           |
|                |           |            | \$            |           |
|                |           |            | s             |           |
|                |           |            | tatic-renewal |           |
|                |           |            | test system   |           |
+----------------+-----------+------------+---------------+-----------+
| Waterflea      | ADBAC     | LOAEC = ND | No            | 423021-01 |
| (*Daphnia      |           | NOAEC =    |               |           |
| magna*)        | 30%       | 0.00415    | \$            |           |
|                |           | MATC = ND  | supplemental  |           |
|                |           | (a.i.)     | study         |           |
|                |           |            |               |           |
|                |           |            | \$ 21-day     |           |
|                |           |            | test duration |           |
|                |           |            |               |           |
|                |           |            | \$ life-cycle |           |
|                |           |            | test          |           |
|                |           |            |               |           |
|                |           |            | \$            |           |
|                |           |            | s             |           |
|                |           |            | tatic-renewal |           |
|                |           |            | test system   |           |
|                |           |            |               |           |
|                |           |            | \$ deviations |           |
|                |           |            | from          |           |
|                |           |            | guideline     |           |
|                |           |            | include MATC  |           |
|                |           |            | not           |           |
|                |           |            | established   |           |
+----------------+-----------+------------+---------------+-----------+

Chronic exposure to ADBAC results in measurable effects on warmwater
fish at a concentration of 75.9 µg a.i./L. The NOAEC was **32.2** ug
a.i./L. This study fulfills guideline requirements for a fish early life
stage chronic test 72-4(a)/OPPTS 850.1400. No measurable adverse effects
on freshwater invertebrates were noted at a concentration of 4.15 µg/L.
However, an MATC could not be determined in this study. Therefore, the
study was classified as supplemental and does not fulfill guideline
requirements for an aquatic invertebrate life cycle test (72-4b/OPPTS
850.1300). The *Daphnia magna* chronic toxicity test must be repeated.

The chronic toxicity of ADBAC, complexed with bentonite clay at varying
concentrations, was also investigated and reported in the open
literature. Results of two tests using a freshwater fish and a
freshwater invertebrate are presented in Table 6.

**Table 6. Chronic Toxicity of Complexed ADBAC to Freshwater Organisms**

+-----------+----------------+--------------+--------------+----------+
| **        | **Chemical,**  | **Endpoint** | **Satisfies  | **Ref    |
| Species** |                |              | G            | erence** |
|           | **% Active     | **(mg/L)**   | uidelines/** |          |
|           | Ingredient**   |              |              | **(MRID  |
|           |                |              | **Comments** | No.)**   |
|           | **(a.i.)**     |              |              |          |
|           |                |              |              |          |
|           | **Tested**     |              |              |          |
+===========+================+==============+==============+==========+
| Fathead   | ADBAC          | LOAEC =      | No           | Dobbs,   |
| Minnow    |                | 2.5:0 for    |              | M.G. et  |
| (*P       | 50% (2.5 mg/L) | survival     | \$           | al.      |
| imephales | plus Bentonite | NOAEC =      | supplemental |          |
| p         | Clay at        | 2.5:25 for   | study        |          |
| romelas)* | concentrations | survival and |              |          |
|           | of 0:0, 2.5:0, | growth       | \$ open      |          |
|           | 2.5:25,        |              | literature   |          |
|           | 2.5:37.5,      | (a.i.)       | study        |          |
|           | 2.5:50 and     |              |              |          |
|           | 2.5:75 mg/L    |              | \$ larval    |          |
|           |                |              | survival and |          |
|           |                |              | growth       |          |
|           |                |              |              |          |
|           |                |              | \$ 7-day     |          |
|           |                |              | test         |          |
|           |                |              | duration     |          |
|           |                |              |              |          |
|           |                |              | \$           |          |
|           |                |              | st           |          |
|           |                |              | atic-renewal |          |
|           |                |              | test system  |          |
|           |                |              |              |          |
|           |                |              | \$ assess    |          |
|           |                |              | de           |          |
|           |                |              | toxification |          |
|           |                |              | of a.i.      |          |
|           |                |              |              |          |
|           |                |              | \$           |          |
|           |                |              | deviations   |          |
|           |                |              | from         |          |
|           |                |              | guideline    |          |
|           |                |              | include lack |          |
|           |                |              | of detailed  |          |
|           |                |              | information  |          |
+-----------+----------------+--------------+--------------+----------+
| Waterflea | ADBAC          | LOAEC =      | No           | Dobbs,   |
| (*Daphnia |                | 2.5:25 for   |              | M.G. et  |
| magna)*   | 50% (2.5 mg/L) | survival     | \$           | al.      |
|           | plus Bentonite | NOAEC =      | supplemental |          |
|           | clay at        | 2.5:37.5 for | study        |          |
|           | concentrations | survival     |              |          |
|           | of 0:0, 2.5:0, | (a.i.)       | \$ open      |          |
|           | 2.5:25,        |              | literature   |          |
|           | 2.5:37.5,      |              |              |          |
|           | 2.5:50 and     |              | \$           |          |
|           | 2.5:75 mg/L    |              | life-cycle   |          |
|           |                |              | test         |          |
|           |                |              |              |          |
|           |                |              | \$ 21-day    |          |
|           |                |              | test         |          |
|           |                |              | duration     |          |
|           |                |              |              |          |
|           |                |              | \$           |          |
|           |                |              | st           |          |
|           |                |              | atic-renewal |          |
|           |                |              | test system  |          |
|           |                |              |              |          |
|           |                |              | \$ assess    |          |
|           |                |              | de           |          |
|           |                |              | toxification |          |
|           |                |              | of a.i.      |          |
|           |                |              |              |          |
|           |                |              | \$           |          |
|           |                |              | deviations   |          |
|           |                |              | from         |          |
|           |                |              | guideline    |          |
|           |                |              | include lack |          |
|           |                |              | of detailed  |          |
|           |                |              | information  |          |
+-----------+----------------+--------------+--------------+----------+

The results of these studies indicate that the chronic toxicity of ADBAC
to freshwater fish and invertebrates is reduced after treatment with
bentonite clay. The bentonite clay was an effective detoxification agent
at all treatment levels except for 2.5:25. The studies do not fulfill
guideline requirements for a fish early life stage chronic test or an
aquatic invertebrate life cycle test.

(5) **Freshwater Invertebrates, Chronic Sediment**

A sediment toxicity study 850.1790 was submitted for ADBAC even though
the data are not required. Results of this study are presented in Table
7.

**Table 7. Chronic Toxicity of Sediment-Incorporated ADBAC to Freshwater
Invertebrates**

+------------+---------------+-------------+--------------+---------+
| *          | **Chemical,** | *           | **Satisfies  | **Refe  |
| *Species** |               | *Endpoint** | G            | rence** |
|            | **% Active    |             | uidelines/** |         |
|            | Ingredient**  | **(mg/kg)** |              | **(MRID |
|            |               |             | **Comments** | No.)**  |
|            | **(a.i.)**    |             |              |         |
|            |               |             |              |         |
|            | **Tested**    |             |              |         |
+============+===============+=============+==============+=========+
| Midge      | ADBAC         | [14-day]{.  | No           | 43      |
|            |               | underline}: |              | 7311-01 |
| (*         | 80%           |             | \$           |         |
| Chironomus |               | LC~50~ =    | supplemental |         |
| tentans*)  |               | 548 LOAEC = | study        |         |
|            |               | 520         |              |         |
|            |               |             | \$ 28-day    |         |
|            |               | NOAEC = 260 | duration     |         |
|            |               |             |              |         |
|            |               | MATC = 368  | \$ sediment  |         |
|            |               |             |              |         |
|            |               | (a.i.)      | \$ static    |         |
|            |               |             | test system  |         |
|            |               | [28-day]{.  |              |         |
|            |               | underline}: | \$           |         |
|            |               |             | deviations   |         |
|            |               | LC~50~ =    | from         |         |
|            |               | 479 LOAEC = | guideline    |         |
|            |               | 1200        | include lack |         |
|            |               |             | of detailed  |         |
|            |               | NOAEC = 520 | information  |         |
|            |               |             | and wide pH  |         |
|            |               | MATC = 790  | range        |         |
|            |               |             |              |         |
|            |               | (a.i.)      |              |         |
+------------+---------------+-------------+--------------+---------+

The results of these studies indicate that exposure to ADBAC in the
sediment results in measurable effects on midges at a concentration of
520 mg/kg after 14-days and at a concentration of 1200 mg/kg after
28-days. This study partially fulfills the guideline requirement for an
acute freshwater sediment acute toxicity test (850.1790).

**(6) Freshwater Fish, Bioconcentration**

Aquatic organisms bioavailability/biomagnification toxicity tests may be
required on a case-by-case basis depending on the results of lower tier
ecological studies and pertinent environmental characteristics. This
testing is not required for ADBAC. However, a bioconcentration study
with a freshwater fish (bluegill) was submitted for review (MRID
410268-01). The results indicate that bioaccumulation of ADBAC in
freshwater fish is not likely to occur. Maximum bioconcentration factors
(BCFs) were 33X for edible tissues (muscle, skin), 160X for nonedible
tissues (viscera, head, carcass), and 79X for whole fish tissues.
However, this study was classified as supplemental and does not fulfill
guideline requirements for a fish bioconcentration test 72-6/OPPTS
850.1730. Further information on this study may be found in the
Environmental Fate Chapter of this RED document.

**C. Toxicity to Aquatic Plants**

Phytotoxicity testing is required for pesticides when certain conditions
of use and environmental fate apply. Testing is conducted with one
species of aquatic vacular plant (*Lemna* *gibba or L. minor*) and four
species of algae: (1) freshwater green alga, *Selenastrum
capricornutum,* (2) marine diatom, *Skeletonema costatum,* (3)
freshwater diatom, *Navicula pelliculosa,* and (4) bluegreen alga,
*Anabaena flos-aquae.* Non-target plant phytotoxicity tests are required
for ADBAC uses having potential for environmental exposure (once through
cooling towers, antisapstain).

A freshwater algal growth study, that evaluated the chronic toxicity of
ADBAC complexed with bentonite clay at various concentrations, was
reviewed. The study was obtained from the open literature. Results of
this study are presented in Table 8.

**Table 8. Toxicity of Complexed ADBAC to Aquatic Plants**

+-----------+------------+-------------+------------------+----------+
| **        | **C        | **Endpoint  | **Satisfies      | **Ref    |
| Species** | hemical,** | (AD         | Guidelines/**    | erence** |
|           |            | BAC:Clay)** |                  |          |
|           | **% Active |             | **Comments**     | **(MRID  |
|           | In         | **(mg/L)**  |                  | No.)**   |
|           | gredient** |             |                  |          |
|           |            |             |                  |          |
|           | **(a.i.)** |             |                  |          |
|           |            |             |                  |          |
|           | **Tested** |             |                  |          |
+===========+============+=============+==================+==========+
| Green     | ADBAC 50%  | LOAEC =     | No               | Dobbs,   |
| alga      | (2.5 mg/L) | 2.5:25 for  |                  | M.G. et  |
| (*Se      | plus       | growth      | \$ supplemental  | al.      |
| lenastrum | Bentonite  |             | study            |          |
| capric    | Clay at    | NOAEC =     |                  |          |
| ornutum)* | conc       | 2.5:37.5    | \$ open          |          |
|           | entrations | for growth  | literature       |          |
|           | of 0:0,    |             |                  |          |
|           | 2.5:25,    |             | \$ growth        |          |
|           | 2.5:37.5,  |             | inhibition       |          |
|           | 2.5:50,    |             |                  |          |
|           | and 2.5:75 |             | \$ 96-hr test    |          |
|           | mg/L       |             | duration         |          |
|           |            |             |                  |          |
|           |            |             | \$               |          |
|           |            |             | static-renewal   |          |
|           |            |             | test system      |          |
|           |            |             |                  |          |
|           |            |             | \$ assess        |          |
|           |            |             | detoxification   |          |
|           |            |             | of a.i.          |          |
|           |            |             |                  |          |
|           |            |             | \$ deviations    |          |
|           |            |             | from guideline   |          |
|           |            |             | include          |          |
|           |            |             | photo-period and |          |
|           |            |             | lack of detailed |          |
|           |            |             | information      |          |
+-----------+------------+-------------+------------------+----------+

The results of this study indicate that bentonite clay is an effective
detoxification agent for all treatment levels except for the 2.5:25
treatment. This study was classified as supplemental and does not
fulfill guideline requirements for an algal toxicity test.

**II. Risk Assessment and Characterization**

Risk assessment integrates the results of the exposure and ecotoxicity
data to evaluate the likelihood of adverse ecological effects. Also
playing a role is the environmental fate of a chemical. The following
sections present a summary of the environmental fate of ADBAC and an
environmental exposure and ecological risk assessment. One method of
integrating the results of exposure and ecotoxicity data is called the
quotient method. For this method, risk quotients (RQs) are calculated by
dividing exposure estimates by ecotoxicity values, both acute and
chronic:

RQ = EXPOSURE/TOXICITY

RQs are then compared to OPP\'s levels of concern (LOCs). These LOCs are
criteria used by OPP to indicate potential risk to nontarget organisms
and the need to consider regulatory action. The criteria indicate that a
pesticide used as directed has the potential to cause adverse effects on
nontarget organisms. LOCs currently address the following risk
presumption categories: (1) acute high - potential for acute risk is
high, and regulatory action may be warranted in addition to restricted
use classification; (2) **acute restricted use** - the potential for
acute risk is high, but this may be mitigated through restricted use
classification; (3) **acute endangered species** - the potential for
acute risk to endangered species is high, and regulatory action may be
warranted; and (4) **chronic risk** - the potential for chronic risk is
high, and regulatory action may be warranted. Currently, AD does not
perform assessments for chronic risk to plants, acute or chronic risks
to nontarget insects, or chronic risk from granular/bait formulations to
mammalian or avian species.

The ecotoxicity test values (i.e., measurement endpoints) used in the
acute and chronic risk quotients are derived from the results of
required studies. Examples of ecotoxicity values derived from the
results of short-term laboratory studies that assess acute effects are:
(1) LC~50~ (fish and birds) (2) LD~50~ (birds and mammals) (3) EC~50~
(aquatic plants and aquatic invertebrates) and (4) EC~25~ (terrestrial
plants). Examples of toxicity test effect levels derived from the
results of long-term laboratory studies that assess chronic effects are:
(1) LOEC (birds, fish, and aquatic invertebrates) (2) NOEC (birds, fish
and aquatic invertebrates) and (3) MATC (Maximum Allowable Toxic
Concentration) (fish and aquatic invertebrates). For birds and mammals,
the NOEC value is used as the ecotoxicity test value in assessing
chronic effects. Other values may be used when justified. Generally, the
MATC (defined as the geometric mean of the NOEC and LOEC) is used as the
ecotoxicity test value in assessing chronic effects to fish and aquatic
invertebrates. However, the NOEC is used if the measurement endpoint is
production of offspring or survival.

Risk presumptions, along with the corresponding RQs and LOCs are
tabulated below.

  -----------------------------------------------------------------------
  **Risk Presumptions for Terrestrial Animals**
  -----------------------------------------------------------------------

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

  ------------------------------------------------------------------------
  Risk Presumption         RQ                                    LOC
  ------------------------ ------------------------------------- ---------

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

  -----------------------------------------------------------------------
  **Birds and Wild Mammals**

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

  ------------------------ ------------------------------------- ---------
  Acute High Risk          EEC^1^/LC~50~ or LD~50~/sqft^2^ or    0.5
                           LD~50~/day^3^                         

  Acute Restricted Use     EEC/LC~50~ or LD~50~/sqft or          0.2
                           LD~50~/day (or LD~50~ \< 50 mg/kg)    

  Acute Endangered Species EEC/LC~50~ or LD~50~/sqft or          0.1
                           LD~50~/day                            

  Chronic Risk             EEC/NOEC                              1
  ------------------------ ------------------------------------- ---------

^1^ abbreviation for Estimated Environmental Concentration (ppm) on
avian/mammalian food items

^2^ [mg/ft^2^]{.underline} ^3^ [mg of toxicant consumed/day]{.underline}

LD~50~ \* wt. of bird LD~50~ \* wt. of bird

  -----------------------------------------------------------------------
  **Risk Presumptions for Aquatic Animals**

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

  ------------------------------- ------------------------------ --------
  Risk Presumption                RQ                             LOC

  Acute High Risk                 EEC^1^/LC~50~ or EC~50~        0.5

  Acute Restricted Use            EEC/LC~50~ or EC~50~           0.1

  Acute Endangered Species        EEC/LC~50~ or EC~50~           0.05

  Chronic Risk                    EEC/MATC or NOEC               1
  ------------------------------- ------------------------------ --------

^1^ EEC = (ppm or ppb) in water

  ------------------------------- ------------------------------ --------
  **Risk Presumptions for                                        
  Plants**                                                       

  Risk Presumption                RQ                             LOC
  ------------------------------- ------------------------------ --------

+-----------------------------------------------------------------------+
| ## Terrestrial and Semi-Aquatic Plants                                |
+-----------------------------------------------------------------------+

  ------------------------------- ------------------------------ --------
  Acute High Risk                 EEC^1^/EC~25~                  1

  Acute Endangered Species        EEC/EC~05~ or NOEC             1
  ------------------------------- ------------------------------ --------

+-----------------------------------------------------------------------+
| ## Aquatic Plants                                                     |
+-----------------------------------------------------------------------+

  ------------------------------- ------------------------------ --------
  Acute High Risk                 EEC^2^/EC~50~                  1

  Acute Endangered Species        EEC/EC~05~ or NOEC             1
  ------------------------------- ------------------------------ --------

^1^ EEC = lbs ai/A

^2^ EEC = (ppb/ppm) in water

> **A. Environmental Fate Assessment Summary (excerpted from the
> Environmental Fate Science Chapter of this RED document)**

The Agency has reviewed various environmental fate studies and reports
submitted for ADBAC. The data indicate that ADBAC is hydrolytically and
photolytically stable under abiotic and buffered conditions. Aquatic
metabolism studies indicate that ADBAC is also stable to microbial
degradation. However, a report on the biodegradability of ADBAC
concluded that the degree of ADBAC biodegradability is variable and is
influenced by the chemical concentration, alkyl chain length, the
presence of anionic moieties and the quantity and characteristics of the
microbial population. Accordingly, ADBAC is considered biodegradable
under aerobic and anaerobic conditions and, therefore, environmentally
acceptable. In addition, ADBAC is immobile in soil because of its strong
tendency to bind to sediment/soil. Bioaccumulation of ADBAC in
terrestrial or aquatic organisms is not likely to occur. Further
information on the environmental fate of ADBAC may be found in the
Environmental Fate Chapter of this RED document.

> **B. Environmental Exposure and Ecological Risk Assessment**

Freshwater and estuarine/marine aquatic organisms and plants could
potentially be exposed to ADBAC discharged into the aquatic environment.
The Agency conducted modeling in 2005 to estimate the exposure and
environment risk resulting from such discharges of ADBAC from the
once-through cooling tower and antisapstain wood treatment uses.

(1) **Tier I 2005 Probabilistic Dilution Modeling for once-through
    cooling tower use**

> The EPA Office of Water PDM4 Model was used to estimate exposure from
> once-through cooling tower use as a preliminary screen in the absence
> of field residue data. Once-through cooling water systems applying a
> continuous dose of pesticide located on low-flow streams (100 million
> gallons per day) were used as the scenarios providing the maximum
> concentrations of ADBAC in the receiving water, e.g., the "worst case"
> scenarios. It was assumed that the chemical was being applied at the
> highest listed maintenance rate shown on any of the ADBAC product
> labels. Actual probabilities of exceedance of concentrations in
> receiving waters are likely lower than what are shown in Table 10 due
> to higher flow rates and possible degradation/ dissipation of
> available ADBAC by mechanisms other than hydrolysis. A summary of
> concentrations over time is provided in Table 10. The concentrations
> selected for analysis were the measured endpoints derived from the
> results of the required studies (see Section I.B.)
>
> **Table 9 - Table of LOC Values**

**Modeling Results for ADBAC -- Once-through Cooling Use**

The following tables list the probability that levels of concern (LOCs)
will be exceeded for aquatic organisms. Various dosages, dosing methods
(continuous vs intermittent), and water flow rates (low, medium, high
stream flow rates) were modeled.

Results are given as percent of days per year and number of days per
year of LOC exceedance for the different aquatic animal and plant
groups. **BOLD** indicates exceedance of LOC (e.g., if the number of
days exceeded is equivalent to or greater than number of days used to
determine the toxicology endpoint, risk is assumed). A maximum dosage of
10.0 ppm was selected from labeling. The lowest estuarine/marine species
endpoint (marine mollusk) was used below.

  ------------------ ----------- ----------- --------------- --------------
  Taxa               LC50/EC50   High Acute  Restricted Use  Endangered
                                 Risk LOC (X LOC (X 0.1)     Species LOC (X
                                 0.5)                        0.05)

  Freshwater fish-   280 ppb     140 ppb     28 ppb          14 ppb
  warm                                                       

  Freshwater fish -- 923 ppb     462 ppb     92 ppb          46 ppb
  cold                                                       

  Freshwater         5.9 ppb     2.95 ppb    0.59 ppb        0.30 ppb
  invertebrate                                               

  Marine fish        860 ppb     **430** ppb 86 ppb          43 ppb

  Marine mollusk     55 ppb      28 ppb      5.5 ppb         2.8 ppb

  Marine             80 ppb      40 ppb      8 ppb           4 ppb
  invertebrate                                               

  Green alga         2500 ppb    n/a         n/a             n/a

  Aquatic vascular   No data                                 
  plant                                                      

  Freshwater fish    32.2 ppb                                
  chronic                                                    
  ------------------ ----------- ----------- --------------- --------------

**[Average Exceedances]{.underline}**

**Table 10 - 5.0 ppm intermittent dose, Low Flow facility ("best
case")**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | 1400 ppb    | **140 ppb** | 322 ppb,    |
|             |             |             |             |             |
|             |             | 0.13%, 0.10 | **10.9%, 40 | 1.35%, 1.0  |
|             |             | days        | days**      | days        |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **\>21.2%,  | **\>21.2%,  |             |
|             |             | \>80days**  | \>80 days** |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **1.99%,    | **\>2.12%,  |             |
|             |             | 7.3 days**  | \>8 days**  |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 4e-10%\..   |             |             |             |
|             | .negligible |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 11 - 5.0** ppm intermittent dose, High flow

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | 1400 ppb    | **140 ppb** | 322 ppb     |
|             |             |             |             |             |
|             |             | 0.038%,     | **18.7%, 68 | 0.81%, 3.0  |
|             |             | negligible  | days**      | days        |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** |             |
|             |             |             |             |             |
|             |             | **\>40.1%,  | **\>40.1%,  |             |
|             |             | \> 150      | \>150       |             |
|             |             | days**      | days**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **1.5%, 6.0 | **\>40.1%,  |             |
|             |             | days**      | \>150       |             |
|             |             |             | days**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 1.33e-8     |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 12 - 10.0** ppm intermittent, Low Flow

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | 1400 ppb    | **Already   | 322 ppb     |
|             |             |             | exceeded by |             |
|             |             | 0.7%, 2.6   | 5.0 ppm     | 4.6%, 17    |
|             |             | days        | dose**      | days        |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 5.0 ppm     | 5.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **Already   |             |
|             |             |             | exceeded by |             |
|             |             | **9.3%,     | 5.0 ppm     |             |
|             |             | 34.2 days** | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 5.99e-7%,   |             |             |             |
|             | negligible  |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 13 - 2.0** ppm continuous, High Flow

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **1400      | **Already   | **322 ppb** |
|             |             | ppb**       | exceeded by |             |
|             |             |             | i           | **422%,     |
|             |             | **147%, 540 | ntermittent | 1540 days** |
|             |             | days**      | doses**     |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | i           | i           |             |
|             |             | ntermittent | ntermittent |             |
|             |             | doses**     | doses**     |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **Already   |             |
|             |             |             | exceeded by |             |
|             |             | **460%,     | i           |             |
|             |             | 1680 days** | ntermittent |             |
|             |             |             | doses**     |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 0.0920%,    |             |             |             |
|             | 0.3 days    |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 14 - 2.0** ppm continuous, Low Flow

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **1400      | **Already   | **322 ppb** |
|             |             | ppb**       | exceeded by |             |
|             |             |             | i           | **198%, 64  |
|             |             | **65%, 239  | ntermittent | days**      |
|             |             | days**      | doses**     |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | i           | i           |             |
|             |             | ntermittent | ntermittent |             |
|             |             | doses**     | doses**     |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **Already   |             |
|             |             |             | exceeded by |             |
|             |             | **224%, 819 | i           |             |
|             |             | days**      | ntermittent |             |
|             |             |             | doses**     |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 0.284%, 1.0 |             |             |             |
|             | days        |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 15 - 5.0 ppm continuous, Low Flow (highest)**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **Already   | **Already   | **322 ppb** |
|             |             | exceeded by | exceeded by |             |
|             |             | 2.0 ppm     | 2.0 ppm     | **350%,     |
|             |             | dose**      | dose**      | 1270 days** |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 2.0 ppm     | 2.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 2.0 ppm     | 2.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | **2500      |             |             |             |
|             | ppb**       |             |             |             |
|             |             |             |             |             |
|             | **2.0%, 7.3 |             |             |             |
|             | days**      |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**[Worst-Case Exceedances]{.underline}**:

**Table 16 - 5.0 ppm intermittent, Medium-flow (lowest worst-case)**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | 1400 ppb    | **140 ppb** | 322.0 ppb   |
|             |             |             |             |             |
|             |             | 0.10%, 0.4  | **22.6%,    | 1.7%,.6.0   |
|             |             | days        | 82.5 days** | days        |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **\>61.7%,  | **\>617%,   |             |
|             |             | \>225       | \>225       |             |
|             |             | days**      | days**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **2.9%,     | **\>61.7%,  |             |
|             |             | 10.5 days** | \>225       |             |
|             |             |             | days**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 3.55e-7%,   |             |             |             |
|             | negligible  |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 17 - 5.0 ppm intermittent, Low-flow**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **1400      | **140 ppb** | **322 ppb** |
|             |             | ppb**       |             |             |
|             |             |             | **Already   | **15.7%,    |
|             |             | **1.6%, 6.0 | exceeded by | 57.3 days** |
|             |             | days**      | medium      |             |
|             |             |             | flow**      |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | medium      | medium      |             |
|             |             | flow**      | flow**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **22.6%,    | **Already   |             |
|             |             | 82.5 days** | exceeded by |             |
|             |             |             | medium      |             |
|             |             |             | flow**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 4.79e-08%,  |             |             |             |
|             | negligible  |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 18 - 10 ppm intermittent, Medium-flow**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | 1400 ppb    | **140 ppb** | 322 ppb     |
|             |             |             |             |             |
|             |             | 0.77%, 3.0  | **Already   | 8.16%, 30   |
|             |             | days        | exceeded by | days        |
|             |             |             | 5.0 ppm     |             |
|             |             |             | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 0.5 ppm     | 5.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 5.0 ppm     | 5.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 7.31 e-06%, |             |             |             |
|             | negligible  |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 19 - 10 ppm intermittent, Low-flow**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **1400      | **140 ppb** | **322 ppb** |
|             |             | ppb**       |             |             |
|             |             |             | **Already   | **49.5%,    |
|             |             | **7.9%, 29  | exceeded by | 180 days**  |
|             |             | days**      | 5.0 ppm     |             |
|             |             |             | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 5.0 ppm     | 5.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | 5.0 ppm     | 5.0 ppm     |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | 2500 ppb    |             |             |             |
|             |             |             |             |             |
|             | 7.17e-7%,   |             |             |             |
|             | neglibile   |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 20 - 2.0 ppm continuous, Medium-flow**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **1400      | **140 ppb** | **322 ppb** |
|             |             | ppb**       |             |             |
|             |             |             | **Already   | **740%,     |
|             |             | **274.3%,   | exceeded by | 2700 days** |
|             |             | 1000 days** | i           |             |
|             |             |             | ntermittent |             |
|             |             |             | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | i           | i           |             |
|             |             | ntermittent | ntermittent |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | i           | 5.0 ppm     |             |
|             |             | ntermittent | dose dose** |             |
|             |             | dose**      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | **2500      |             |             |             |
|             | ppb**       |             |             |             |
|             |             |             |             |             |
|             | **0.242%,   |             |             |             |
|             | 10 days**   |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

**Table 21 - 5.0 ppm continuous, Low-flow (highest worst-case)**

+-------------+-------------+-------------+-------------+-------------+
|             |             | Levels of   |             |             |
|             |             | Concern     |             |             |
|             |             | (LOCs)      |             |             |
+-------------+-------------+-------------+-------------+-------------+
| Taxa        | Endpoint    | Acute       | Endangered  | Chronic     |
|             | value (from | Nontarget   | Species     | (NOEC)      |
|             | study)      | (LC50 or    | (LC50 or    |             |
|             |             | EC50 \*     | EC50 \*     |             |
|             |             | 0.5)        | 0.05)       |             |
+-------------+-------------+-------------+-------------+-------------+
| FW fish     | 280 ppb     | **1400      | **140 ppb** | **322 ppb** |
|             |             | ppb**       |             |             |
|             |             |             | **Already   | **Already   |
|             |             | **Already   | exceeded by | exceeded by |
|             |             | exceeded by | i           | 2.0 pm      |
|             |             | 2.0 ppm     | ntermittent | dose**      |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| FW invert   | 5.9 ppb     | **30 ppb**  | **3.0 ppb** | n/a         |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | i           | i           |             |
|             |             | ntermittent | ntermittent |             |
|             |             | dose**      | dose**      |             |
+-------------+-------------+-------------+-------------+-------------+
| ME mollusk  | 55 ppb      | **280 ppb** | **2.8 ppb** |             |
|             |             |             |             |             |
|             |             | **Already   | **Already   |             |
|             |             | exceeded by | exceeded by |             |
|             |             | i           | i           |             |
|             |             | ntermittent | ntermittent |             |
|             |             | dose**      | ppm dose**  |             |
+-------------+-------------+-------------+-------------+-------------+
| Green alga  | **2500      |             |             |             |
|             | ppb**       |             |             |             |
|             |             |             |             |             |
|             | **23.1%, 84 |             |             |             |
|             | days**      |             |             |             |
+-------------+-------------+-------------+-------------+-------------+

Tier I once-through cooling tower modeling indicates that ADBAC use will
result in acute and chronic risk to non-endangered and
endangered/threatened freshwater fish and acute risk to other aquatic
animals at all 3 dosages modeled: 2.0 ppm, 5.0 ppm, and 10.0ppm. High
water flow, intermittent dosing at 10.0 ppm had less acute and chronic
impact on non-endangered freshwater fish than medium to low stream flow.
However, all LOC\'s were triggered at the 2.0 ppm dosage using
continuous dosing regardless of high, medium, or low stream flow. The
nontarget plant LOC is triggered at all 3 continuous dosages modeled.

**(2) Antisapstain Wood Leaching Model**

The ADBAC antisapstain wood treatment use was modeled using Krahn and
Strub - 1990, to estimate expected environmental concentrations
(EEC\'s). The EEC is an estimate of the amount of ADBAC that will runoff
from antisapstain treated wood exposed to the elements when stored
outdoors. The chemical formulation, retention of antisapstain by the
wood, rough vs smooth wood surfaces, amount and timing of precipitation,
and storage site conditions are some of the variables that affect the
amount and timing of runoff. A total of 16 rain cycles of equal
intensity and duration were used in this model.

> **Table 22 - Table of LOCs**

+-----------------+----------+-----------+--------------+-------------+
| Taxa            | L        | High      | Restricted   | Endangered  |
|                 | C50/EC50 | Acute     | Use LOC (X   | Species LOC |
|                 |          | Risk LOC  | 0.1)         | (X 0.05)    |
|                 |          | (X 0.5)   |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Freshwater      | 280 ppb  | 140 ppb   | 28 ppb       | 14 ppb      |
| fish- warm      |          |           |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Freshwater fish | 923 ppb  | 462 ppb   | 92 ppb       | 46 ppb      |
| -- cold         |          |           |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Freshwater in   | 5.9 ppb  | 2.95 ppb  | 0.59 ppb     | 0.30 ppb    |
|                 |          |           |              |             |
| Vertebrate      |          |           |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Marine fish     | 860 ppb  | **430**   | 86 ppb       | 43 ppb      |
|                 |          | ppb       |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Marine mollusk  | 55 ppb   | 28 ppb    | 5.5 ppb      | 2.8 ppb     |
+-----------------+----------+-----------+--------------+-------------+
| Marine          | 80 ppb   | 40 ppb    | 8 ppb        | 4 ppb       |
| invertebrate    |          |           |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Green alga      | 2500 ppb | n/a       | n/a          | n/a         |
+-----------------+----------+-----------+--------------+-------------+
| Aquatic         | No data  |           |              |             |
| vascular plant  |          |           |              |             |
+-----------------+----------+-----------+--------------+-------------+
| Freshwater fish | 32.2 ppb |           |              |             |
| chronic         |          |           |              |             |
+-----------------+----------+-----------+--------------+-------------+

The maximum amount of leachate from the antisapstain treated wood that
was predicted by this model totaled 3.92 ppb. The lowest predicted
amount of leachate was 1.02 ppb and the typical amount was 1.57 ppb.
LC50 values for fish range from 280 to 860 ppb, and for estuarine
invertebrates range from 55 to 92 ppb. Freshwater invertebrates are the
most sensitive aquatic animals to ADBAC with an acute EC50 of 5.9 ppb,
and a chronic NOAEC of 4.1 ppb.

Non-endangered/threatened aquatic species (fish, invertebrates, green
algae) are not expected to be adversely affected - acute or chronic
toxicity - based on LOCs above. Endangered/threatened fish (freshwater
and marine/estuarine) and green algae are not expected to be adversely
affected by the antisapstain use. However, freshwater and marine aquatic
invertebrate endangered/threatened species are at risk from the
antisapstain use.

**[Conclusions]{.underline}**:

[Once-through Cooling Tower Use]{.underline}

Tier I once-through cooling tower modeling indicates that ADBAC use will
result in acute and chronic risk to non-endangered and
endangered/threatened freshwater fish and acute risk to other aquatic
animals at all 3 dosages modeled: 2.0 ppm, 5.0 ppm, and 10.0ppm. High
water flow, intermittent dosing at 10.0 ppm had less acute and chronic
impact on non-endangered freshwater fish than medium to low stream flow.
However, all LOC\'s were triggered at the 2.0 ppm dosage using
continuous dosing regardless of high, medium, or low stream flow. The
nontarget plant LOC is triggered at all 3 continuous dosages modeled.
The aquatic plant risk assessment is incomplete due to a number of
outstanding studies (see section II. 1. Confirmatory Data Required).

The high vs medium vs low water flow rate is based on size of the
facility. Generally, higher flow (e.g., \> 1000 MGD) would use more
chemical than smaller facilities, but the pattern does not hold true
across the board, probably because model input values are based on
different receiving water ("reach") data for individual facilities. This
model uses 7Q10 rainfall conditions, which is essentially the worst-case
drought of a 10 year period. Variables such as stream flow rate and
ADBAC dissipation, degradation, and 1/2 life were not considered in this
Tier I model but should be considered in higher tier modeling. Field
monitoring is suggested in the absence of higher Tier modeling. Risk
mitigation recommendations should be based on dosing method (e.g.
intermittent vs continuous) and application rate instead of facility
size, however, risk mitigation is not recommended at this time.

[Antisapstain Wood Treatment Use]{.underline}

The maximum amount of leachate from antisapstain treated wood per the
Krahn and Strub, 1990 model totaled 3.92 ppb. The lowest predicted
amount of leachate was 1.02 ppb and the typical amount was 1.57 ppb.
LC50 values for fish range from 280 to 860 ppb, and for estuarine
invertebrates range from 55 to 92 ppb. Freshwater invertebrates are the
most sensitive aquatic animals to ADBAC with an acute EC50 of 5.9 ppb,
and a chronic NOAEC of 4.1 ppb. Non-endangered/threatened aquatic
species (fish, invertebrates, green algae) are not expected to be
adversely affected - acute or chronic toxicity - based on LOCs.
Endangered/threatened fish and green algae species are not expected to
be adversely affected by the antisapstain use. Due to the extreme
sensitivity of freshwater and marine aquatic invertebrates to ADBAC,
methods such as indoor or covered wood storage and/or containment of
runoff water via berms or plastic barriers in outdoor storage areas are
suggested. ADBAC is tightly adsorbed to clay and organic matter which
greatly reduces potential for ADBAC to leach downward through soil to
groundwater, and will serve to reduce surface runoff as well. The Tier I
screening model is only intended as a screening-level model, and, as
such, has inherent uncertainties and limitations which may result in
inaccurate exposure estimations, further refinement of the model is
recommended before any regulatory action is taken regarding the
antisapstain uses of ADBAC. An environmental monitoring study of runoff
from antisapstain treatment facilities is needed to address the
potential risks and to provide EECs for use in a refined risk
assessment. Additionally, impacts from the antisapstain use could
potentially be mitigated with precautions to prevent leaching and runoff
when wood is stored outdoors.

C.  **Endangered Species Considerations**

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2),
requires all federal agencies to consult with the National Marine
Fisheries Service (NMFS) for marine and andronomus listed species, or
the United States Fish and Wildlife Services (FWS) for listed wildlife
and freshwater organisms, if they are proposing an \"action\" that may
affect listed species or their designated habitat. Each federal agency
is required under the Act to insure that any action they authorize,
fund, or carry out is not likely to jeopardize the continued existence
of a listed species or result in the destruction or adverse modification
of designated critical habitat. To jeopardize the continued existence of
a listed species means \"to engage in an action that reasonably would be
expected, directly or indirectly, to reduce appreciably the likelihood
of both the survival and recovery of a listed species in the wild by
reducing the reproduction, numbers, or distribution of the species.\" 50
C.F.R. \' 402.02.

To facilitate compliance with the requirements of the Endangered Species
Act subsection (a)(2) the Environmental Protection Agency, Office of
Pesticide Programs has established procedures to evaluate whether a
proposed registration action may directly or indirectly reduce
appreciably the likelihood of both the survival and recovery of a listed
species in the wild by reducing the reproduction, numbers, or
distribution of any listed species (U.S. EPA 2004). After the Agency=s
screening-level risk assessment is performed, if any of the Agency=s
Listed Species LOC Criteria are exceeded for either direct or indirect
effects, a determination is made to identify if any listed or candidate
species may co-occur in the area of the proposed pesticide use. If
determined that listed or candidate species may be present in the
proposed use areas, further biological assessment is undertaken. The
extent to which listed species may be at risk then determines the need
for the development of a more comprehensive consultation package as
required by the Endangered Species Act.

For certain use categories, the Agency assumes there will be minimal
environmental exposure, and only a minimal toxicity data set is required
(Overview of the Ecological Risk Assessment Process in the Office of
Pesticide Programs U.S. Environmental Protection Agency - Endangered and
Threatened Species Effects Determinations, 1/23/04, Appendix A, Section
IIB, pg.81). Chemicals in these categories therefore do not undergo a
full screening-level risk assessment, and are considered to fall under a
Ano effect@ determination (NE). The majority of ADBAC uses are spray
applications to indoor surfaces, truck interiors, kennels, institutional
areas, household areas, recirculating cooling towers, evaporative
condensers, pulp/paper mills, swimming pools and spas, and oil field mud
treatments to name a few and fall into this category for the following
reasons:

1.  The amount that will actually reach the environment is very small
    based on usage data and use patterns (no homeowner/residential use
    for bathrooms) and containment methods (retaining ponds,
    recirculation, low residual upon release).

2.  Breakdown in the environment and via sewage treatment is rapid and
    well documented in the literature (See Environmental Fate Chapter
    for more detail). The agency requires the following label statement:
    \"Do not discharge effluent containing this product into lakes,
    streams, ponds, estuaries, oceans, or other waters unless in
    accordance with the requirements of a National Pollutant Discharge
    Elimination System (NPDES) permit and the permitting authorities are
    notified in writing prior to discharge. Do not discharge effluent
    containing this product to sewer systems without previously
    notifying the local sewage treatment plant authority. For guidance
    contact your State Water Board or Regional Office of the EPA.\"

ADBAC uses that have potential for direct release into the environment
or runoff to surface waters include once-through cooling tower and
antisapstain wood treatment uses respectively. These uses are considered
to be representative of having worst-case potential for impacting the
environment. Therefore, these sites were modeled.

The "best case" once-through cooling tower scenario using 1/2 the
maximum recommended label dosage intermittently applied in a low water
flow resulted in several LOC exceedances including freshwater fish,
freshwater invertebrates, and marine invertebrates. Green algae were not
adversely affected except from use of continuous dosing in combination
with low stream flow conditions. The agency is not aware of any
endangered or threatened green algae. Because ADBAC is rapidly adsorbed
to organic materials and clay, impacts to aquatic organisms may be less
than modeled. The once-through cooling tower model does not account for
degradation and therefore, further assessment is required prior to
making an agency endangered species determination.

Endangered/threatened fish and green algae species are not expected to
be adversely affected by the antisapstain use. However, based on LOC\'s
above both freshwater and marine aquatic invertebrate
endangered/threatened species are at risk from the antisapstain use.
Impacts from the antisapstain use are not expected to occur as long as
precautions are taken to prevent leaching when wood is stored outdoors.
Using Tier I screening modeling to assess potential exposure from
antisapstain wood preservation uses of ADBAC, risks to Listed Species
are indicated. Since the model is only intended as a screening-level
model, and, as such, has inherent uncertainties and limitations which
may result in inaccurate exposure estimations, further refinement of the
model is recommended before any regulatory action is taken regarding the
antisapstain uses of ADBAC. An environmental monitoring study of runoff
from antisapstain treatment facilities is needed to address the
potential risks and to provide EECs for use in a refined risk
assessment. Additionally, impacts from the antisapstain use could
potentially be mitigated with precautions to prevent leaching and runoff
when wood is stored outdoors. Due to these circumstances, the Agency
defers making a determination for the antisapstain uses of ADBAC until
additional data and modeling refinements are available. At that time,
the environmental exposure assessment of the antisapstain use of ADBAC
will be revised, and the risks to Listed Species will be reconsidered.

**III. Confirmatory Data Required**

**1. Non-target Plant Phytotoxicity Studies are Required:** 850.4225
(seedling emergence using rice), 850.4250 (vegetative vigor using rice),
850.4400 (*Lemna gibba*), 850.5400 (Algal toxicity, 4 species: green
alga Selenastrum capricornutum *or Pseudokirshneriella subcapitata*,
blue-green cyanobacteria *Anabeana flos-aquae*, freshwater diatom
*Navicula pelliculosa*, marine diatom *Skeletonema costatum*).

**2. Acute Eastern Oyster embryo larvae study is required:** 850.1055.

**3. Chronic *Daphnia magna* study is required:** 850.1300

**4. Monitoring and/or Tier II modeling of once-through cooling tower
and antisapstain uses to establish EEC\'s for risk assessment.**

**IV. Label Hazard Statements for Terrestrial and Aquatic Organisms and
Use Recommendations**

ADBAC labels must state:

\"This pesticide is toxic to fish, aquatic invertebrates, oysters, and
shrimp\".

\"Do not discharge effluent containing this product into lakes, streams,
ponds, estuaries, oceans, or other waters unless in accordance with the
requirements of a National Pollutant Discharge Elimination System
(NPDES) permit and the permitting authorities are notified in writing
prior to discharge. Do not discharge effluent containing this product to
sewer systems without previously notifying the local sewage treatment
plant authority. For guidance contact your State Water Board or Regional
Office of the EPA.\"

Antisapstain labels must state: \"Treated lumber must not be store
outdoors without precautions to prevent leaching by rainfall to the
environment. Suitable precautions include: covering wood with plastic or
other impervious covering, installation of berms and placement of
plastic under the wood to prevent surface water runoff away from the
storage area.\"

**V. REFERENCES**

Dobbs, M.G., D.S. Cherry, J.C. Scott, and J.C. Petrille. 1995.
Environmental Assessment of an Alkyl Dimethyl Benzyl Ammonium Chloride
(ADBAC) Based Molluscicide Using Laboratory Tests. Published data.
Proceedings of the Fifth International Zebra Mussel and Other Aquatic
Nuisance Organisms Conference, Toronto, Canada.

Krahn, P.K. and R. Strub. 1990. Standard leaching test for antisapstain
chemicals. Regional Program Report 90-10. Environment Canada,
Conservation and Protection, Environmental Protection, Pacific and Yukon
Region, North Vancouver, B.C.

MRID 410268-01. Fackler, P. 1989. Bioconcentration and Elimination of
^14^C-Residues by Bluegill *(Lepomis macrochirus*) Exposed to Alkyl
Dimethyl Benzyl Ammonium Chloride (ADBAC). Project
No.11572-0287-6103-140B. Unpublished data. Conducted by Springborn Life
Sciences, Inc. for ADBAC Quat Joint Venture/Chemical Specialties
Manufacturers Association.

MRID 419472-01. Pate, H.O. and D.O. McIntyre. 1991. Daily Static-Renewal
Acute 96-Hour Toxicity Test of Alkyl Dimethyl Benzyl Ammonium Chloride
(ADBAC) to Bluegill Sunfish. Study No. SC890050. Unpublished data.
Conducted by Battelle Columbus Division for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 419472-02. Pate, H.O. and D.O. McIntyre. 1991. Daily Static-Renewal
Acute 96-Hour Toxicity Test of Alkyl Dimethyl Benzyl Ammonium Chloride
(ADBAC) to Rainbow Trout. Study No. SC890051. Unpublished data.
Conducted by Battelle Columbus Division for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 419472-03. Pate, H.O. and D.O. McIntyre. 1991. Daily Static-Renewal
Acute 48-Hour Toxicity Test of Alkyl Dimethyl Benzyl Ammonium Chloride
(ADBAC) to *Daphnia magna*. Study No. SC 890052. Unpublished data.
Conducted by Battelle Columbus Division for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 423021-01. McIntyre, D.O. and H.O. Pate. 1992. Daily Static-Renewal
Chronic 21-Day Toxicity Test of Alkyl Dimethyl Benzyl Ammonium Chloride
(ADBAC) to *Daphnia magna*. Study No. SC890056. Unpublished data.
Conducted by Battelle Columbus Division for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 423021-02. McIntyre, D.O. and H.O. Pate. 1992. Daily Static-Renewal
Early Life Stage Toxicity Test of Alkyl Dimethyl Benzyl Ammonium
Chloride (ADBAC) to Fathead Minnows. Project No. SC890057. Unpublished
data. Conducted by Battelle Columbus Operations for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 424795-01. Sved, D.W., J.P. Swigert, and G.J. Smith. 1992. A
96-Hour Static-Renewal Acute Toxicity Test with Alkyl Dimethyl Benzyl
Ammonium Chloride (ADBAC) in the Saltwater Mysid (*Mysidopsis bahia)*.
Project No. 350A-101A. Unpublished data. Conducted by Wildlife
International Ltd. for ADBAC Quat Joint Venture/Chemical Specialties
Manufacturers Association.

MRID 424795-02. Sved, D.W., J.P. Swigert, and G.J. Smith. 1992. A
96-Hour Static-Renewal Acute Toxicity Test with Alkyl Dimethyl Benzyl
Ammonium Chloride (ADBAC) in the Sheepshead Minnow (*Cyprinodon
variegatus)*. Project No. 350A-102. Unpublished data. Conducted by
Wildlife International Ltd. for ADBAC Quat Joint Venture/Chemical
Specialties Manufacturers Association.

MRID 424795-03. Sved, D.W., J.P. Swigert, and G.J. Smith. 1992. A
48-Hour Static Acute Toxicity Test with Alkyl Dimethyl Benzyl Ammonium
Chloride (ADBAC) in Embryo Larvae of the Eastern Oyster (*Crassostrea
virginica)*. Unpublished data. Conducted by Wildlife International Ltd.
for ADBAC Quat Joint Venture/Chemical Specialties Manufacturers
Association.

MRID 428859-01. Campbell, S.M. and M. Jaber. 1993. An Acute Oral
Toxicity Study with Alkyl Dimethyl Benzyl Ammonium Chloride (ADBAC) in
the Northern Bobwhite Quail. Project No. 289-109. Unpublished data.
Conducted by Wildlife International Ltd. for Lonza, Inc.

MRID 437311-01. England, D.C. and T. Leak. 1995. Chronic Toxicity of
Sediment-Incorporated ADBAC to *Chironomus tentans*. Project No. 41004.
Unpublished data. Conducted by ABC Laboratories, Inc. for ADBAC Quat
Joint Venture/Chemical Specialties Manufacturers Association.

MRID 437401-01. Sword, M.C. and L. Stuerman. 1993. Static-Renewal Acute
Toxicity of ADBAC to Fathead Minnow (*Pimephales promelas)* in Dilution
Water Amended with 20 mg/L Humic Acid. Study No. 41235. Unpublished
data. Conducted by ABC Laboratories, Inc. for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 437401-02. Sword, M.C. and L. Stuerman. 1993. Static-Renewal Acute
Toxicity of ADBAC to Fathead Minnow (*Pimephales promelas)* in Dilution
Water Amended with 10 mg/L Humic Acid. Study No. 41236. Unpublished
data. Conducted by ABC Laboratories, Inc. for ADBAC Quat Joint
Venture/Chemical Specialties Manufacturers Association.

MRID 437401-03. Sword, M.C. and L. Stuerman. 1993. Static-Renewal Acute
Toxicity of ADBAC to Fathead Minnow (*Pimephales promelas)*. Study No.
41237. Unpublished data. Conducted by ABC Laboratories, Inc. for ADBAC
Quat Joint Venture/Chemical Specialties Manufacturers Association.

[^1]:
    > Comparable to typical ADBAC Manufacturing Use Product (MUP) 80%
    > with regard to actual composition of ADBAC and its impurities.

[^2]:
    > \* Comparable to typical ADBAC Manufacturing Use Product (MUP) 80%
    > with regard to actual

    composition of ADBAC and its impurities