![](media/image3.wmf){width="2.426388888888889in"
height="0.7152777777777778in"}

**Environmental Fate and Ecological Risk Assessment for the
Reregistration of Chlormequat Chloride**

![](media/image4.wmf){width="2.832638888888889in"
height="1.4319444444444445in"}

**Cycocel^®^**

**CAS No. 00999-81-5 PC Code 018101**

+---------------------------------------+------------------------------+
| ***Prepared by:***                    | U.S. Environmental           |
|                                       | Protection Agency            |
| Brian D. Kiernan, Biologist           |                              |
|                                       | Office of Pesticide Programs |
| Marietta Echeverria, Environmental    |                              |
| Scientist                             | Environmental Fate and       |
|                                       | Effects Division             |
|                                       |                              |
|                                       | Environmental Risk Branch IV |
|                                       |                              |
|                                       | 1200 Pennsylvania Ave., NW   |
|                                       |                              |
|                                       | Mail Code 7507P              |
|                                       |                              |
|                                       | Washington, DC 20460         |
+---------------------------------------+------------------------------+
| ***Reviewed by:***                    |                              |
|                                       |                              |
| Thomas Steeger, Ph.D., Senior         |                              |
| Biologist                             |                              |
|                                       |                              |
| R. David Jones, Ph.D., Senior         |                              |
| Agronomist                            |                              |
|                                       |                              |
| Elizabeth Behl, Branch Chief          |                              |
+---------------------------------------+------------------------------+

#   {#section .unnumbered}

I. Executive Summary [4](#i.-executive-summary)

A. Nature of the Chemical Stressor [4](#nature-of-the-chemical-stressor)

B. Conclusions -- Exposure Characterization
[4](#conclusions-exposure-characterization)

C. Conclusions -- Effects Characterization
[4](#conclusions-effects-characterization)

D. Potential Risks to Non-target Organisms
[4](#potential-risks-to-non-target-organisms)

E. Data Gaps and Uncertainties [5](#data-gaps-and-uncertainties)

II\. Problem Formulation [6](#ii.-problem-formulation)

A. Stressor Source and Distribution
[6](#a.-stressor-source-and-distribution)

1\. Source and Intensity [6](#source-and-intensity)

2\. Physical/Chemical/Fate and Transport Properties
[6](#number-range-chapterphysicalchemicalfate-and-transport-properties)

3\. Pesticide Type, Class, and mode of Action
[7](#pesticide-type-class-and-mode-of-action)

4\. Usage Overview [7](#usage-overview)

B. Receptors [7](#b.-receptors)

C. Assessment Endpoints [8](#c.-assessment-endpoints)

D. Conceptual Model [9](#d.-conceptual-model)

5\. Diagram [9](#diagram)

6\. Risk Hypothesis [10](#risk-hypothesis)

E. Analysis Plan [10](#e.-analysis-plan)

II\. Analysis [11](#analysis)

A. Use Characterization [11](#use-characterization)

B. Exposure Characterization [12](#exposure-characterization)

1\. Environmental Fate and Transport Characterization
[12](#environmental-fate-and-transport-characterization)

2\. Aquatic Exposure [14](#aquatic-exposure)

3\. Terrestrial Exposure [17](#terrestrial-exposure)

C. Ecological Effects Characterization
[18](#ecological-effects-characterization)

1\. Aquatic Effects [19](#aquatic-effects)

2\. Terrestrial Effects [20](#terrestrial-effects)

3\. ECOTOX [21](#ecotox)

III\. Risk Characterization [21](#risk-characterization)

A. Risk Estimation [22](#risk-estimation)

1\. Aquatic Species [23](#aquatic-species)

2\. Terrestrial [24](#terrestrial)

B. Risk Description [27](#risk-description)

1\. Aquatic [28](#aquatic)

2\. Terrestrial [28](#terrestrial-1)

C. Uncertainties and Data Gaps [31](#uncertainties-and-data-gaps)

IV\. Conclusion [32](#conclusion)

V. Threatened and Endangered Species
[33](#threatened-and-endangered-species)

A. Action Area [34](#action-area)

B. Taxonomic Groups Potentially at Risk
[34](#taxonomic-groups-potentially-at-risk)

C. Indirect Effects Analysis [35](#indirect-effects-analysis)

D. Critical Habitat [36](#critical-habitat)

E. Co-occurrence Analysis [36](#co-occurrence-analysis)

VI.References [37](#references)

VII\. Appendix I. Environmental Fate and Transport Data
[38](#appendix-i.-environmental-fate-and-transport-data)

VIII\. Appendix II. PRZM/EXAMS Output Files
[41](#appendix-ii.-przmexams-output-files)

IX\. Appendix III. TREX Model Information
[45](#appendix-iii.-trex-model-information)

X. Appendix IV. TerrPlant Model [46](#appendix-iv.-terrplant-model)

XI\. Appendix V. Individual Effect Chance Model
[48](#appendix-v.-individual-effect-chance-model)

XII\. Appendix VI. Endangered Species Count from the LOCATES Database by
Listed Taxon for each Crop
[52](#appendix-vi.-endangered-species-count-from-the-locates-database-by-listed-taxon-for-each-crop)

#   {#section-1 .unnumbered}

# I. Executive Summary

The intent of this document is to review the environmental fate and
potential ecological effects associated with the outdoor uses of
chlormequat chloride on bedding plants and containerized nursery crops
(Cycocel^®^; EPA Reg. No. 241-74).

## Nature of the Chemical Stressor

Chlormequat chloride is also registered for use on indoor greenhouse
ornamental crops, but these uses are not evaluated in this assessment.
Chlormequat chloride, the sole active ingredient in Cycocel^®^, is a
plant growth regulator (PGR) applied as a drench or spray to greenhouse
plants and proposed outdoor spray on containerized ornamentals.
[]{.mark}

## Conclusions -- Exposure Characterization

Chlormequat chloride is expected to be moderately mobile to mobile (FAO
classification scheme) in the environment. Major routes of dissipation
in the environment include microbial degradation in soils and aquatic
systems; however, the extent to which the chemical is subject to abiotic
routes of degradation is unknown since no data are currently available.
There is uncertainty regarding chlormequat chlorides' persistence in the
environment. In aerobic soil metabolism studies, chlormequat chloride
degraded with half-lives ranging from 4-6 weeks. But there were
significant unidentified residues in these studies. Including the
unidentified residues in the half-life estimates increases them to \~
1-4 months. In aquatic environments, chlormequat chloride was
short-lived, degrading with half-lives of \~ 1 week. However,
significant non-extractable residues were detected in these studies and
it is uncertain whether or not they consist of parent chlormequat
chloride and/or residues of risk concern.

## Conclusions -- Effects Characterization

For aquatic organisms on an acute exposure basis, chlormequat chloride
is classified as practically non-toxic to freshwater and
estuarine/marine fish, slightly toxic to freshwater and estuarine/marine
invertebrates, and moderately toxic to aquatic plants. For terrestrial
organisms, chlormequat chloride is categorized as slightly toxic to
birds, moderately toxic to mammals and practically non-toxic to
honeybees on an acute exposure basis. Chronic toxicity endpoints for
birds and mammals include decreases in weight gain. Sublethal effects in
birds also included eggshell thinning and decreased testicular weight,
effects often associated with endocrine-mediated processes. Sensitive
terrestrial plants can be adversely affected by chlormequat chloride.

## Potential Risks to Non-target Organisms

Based on this screening-level assessment, the proposed new use of
chlormequat chloride could result in acute and chronic risk to
terrestrial animals, risk to terrestrial plants and Federally-listed
threatened and endangered (listed) aquatic vascular plant species.
Adverse effects to terrestrial or aquatic plants could affect primary
productivity in their respective ecosystems, leading to effects on
higher trophic levels. The acute risk level of concern (LOC) is exceeded
for birds foraging on short grass, tall grass and broadleaf plants/small
insects and for small-sized (20g) birds foraging on
fruits/pods/seeds/large insects (RQs 0.45-6.9). The listed species LOC
is also exceeded for small- and medium-sized (100g) birds foraging on
fruits/pods/large insects. While a NOAEC was not determined for birds,
using the lowest dietary concentration tested indicates potential
chronic risk to birds in all forage classes. There is potential acute
risk to mammals foraging on short grass, tall grass and broadleaf
plant/small insects (RQs 0.45-2.2), and the listed species LOC is
exceeded for small (15g) and medium size (35g) classes foraging on
fruits/pods/large insects. Potential chronic risk to mammals is
indicated for all size classes for the short grass, tall grass and
broadleaf plant/small insect forage classes. **Table 1** summarizes the
listed taxa potentially at risk from direct and/or indirect effects due
to the outdoor applications of chlormequat chloride.

## Data Gaps and Uncertainties

There are several data gaps that increase the uncertainty of this
assessment. There are currently no acceptable data for hydrolysis,
photolysis, anaerobic soil metabolism or terrestrial field dissipation.
In the absence of data, it was assumed that chlormequat chloride is
stable to hydrolysis, photolysis and anaerobic metabolism. In the
aerobic soil and aerobic aquatic metabolism studies all transformation
products greater than 10% of the applied may not have been identified. A
total residue approach was used for calculating the aerobic soil
metabolism half-life for exposure modeling.

There are currently no data regarding the toxicity of chlormequat
chloride to freshwater fish on a chronic exposure basis. Although use of
the acute to chronic ratio for daphnids suggests the likelihood of
chronic risk to freshwater fish is low, potential for risk is presumed.
Additionally, there are no data available to evaluate the potential
chronic risk to estuarine/marine organisms.

The avian reproduction study with chlormequat chloride did not determine
the necessary NOAEC due to significant treatment-related effects at all
treatment levels. The terrestrial plant seedling emergence study also
did not establish a NOEC, also due to effects at all treatment levels.
These deficiencies increase the uncertainty in the assessment.

Since there are no specific nursery scenarios for aquatic exposure
modeling, surrogate scenarios were used. The turf scenarios were chosen
as surrogates because they consist of high organic matter top soil
layers that are similar to soils used for bedding plants in nurseries.
However, the extent to which the meteorologic, edaphic and agronomic
characteristics of the surrogate scenarios are representative of actual
use sites in nurseries is uncertain. []{.mark}

[]{.mark}

**Table 1**. Listed species risks associated with potential direct or
indirect effects due to the proposed applications of chlormequat
chloride in containerized ornamental production.

+------------------+-----------------+---------------+----------------+
| **Listed Taxon** | **Direct        | **Direct      | **Indirect     |
|                  | Effects**       | Effects**     | Effects**      |
|                  |                 |               |                |
|                  | **Acute**       | **Chronic**   |                |
+------------------+-----------------+---------------+----------------+
| Terrestrial and  | Yes             | \-            | Yes^1^         |
| semi-aquatic     |                 |               |                |
| plants -         |                 |               |                |
| monocots         |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Terrestrial and  | Yes             | \-            | Yes^1^         |
| semi-aquatic     |                 |               |                |
| plants - dicots  |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Insects          | No              | \-            | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Birds            | Yes             | Yes           | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Terrestrial      | Yes             | Yes           | Yes^1^         |
| phase amphibians |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Reptiles         | Yes             | Yes           | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Mammals          | Yes             | Yes           | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Aquatic plants   | Yes             | \-            | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Freshwater fish  | No              | No data^2^    | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Aquatic phase    | No              | No data       | Yes^1^         |
| amphibians       |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Freshwater       | No              | No            | Yes^1^         |
| invertebrates    |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Mollusks         | No data         | No data       | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Marine/estuarine | No              | No data       | Yes^1^         |
| fish             |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Marine/estuarine | No              | No data       | Yes^1^         |
| crustaceans      |                 |               |                |
+------------------+-----------------+---------------+----------------+

^1^Unlisted LOC exceeded for terrestrial and aquatic vascular plants,
therefore there is potential for adverse effects to those species that
rely either on a specific plant species or multiple plant species. Plant
indirect effects may include general habitat modification, host plant
loss, and food supply disruption.

^2^When data are unavailable, risk is presumed.

# II. Problem Formulation {#ii.-problem-formulation .unnumbered}

## A. Stressor Source and Distribution {#a.-stressor-source-and-distribution .unnumbered}

### Source and Intensity

This screening-level environmental fate and ecological risk assessment
evaluates the potential risk to non-target organisms from the outdoor
use of chlormequat chloride as a backpack or ground spray on
containerized ornamentals and bedding plants in nurseries, shadehouses
and other non-enclosed structures. Chlormequat chloride, the sole active
ingredient in Cycocel^®^, is a plant growth regulator (PGR) registered
for application as a drench or spray to greenhouse plants. Number range
CHAPTERFor outdoor use of chlormequat chloride, the compound can be
applied at a maximum rate of 33.3 lbs ai/A/year. Greenhouse uses were
not considered since aquatic and terrestrial exposures are expected to
be minimal due to the closed-system nature of their operations and
discharges from greenhouses must be regulated in accordance with a NPDES
permit under the Clean Water Act.

According to the product labels, a primary use of chlormequat chloride
is as a tank mix with another PGR, B-nine^®^ (daminozide; EPA Reg. No.
400-69).

### Number range CHAPTERPhysical/Chemical/Fate and Transport Properties

Chlormequat chloride is the salt of a quaternary ammonium cation, a
diverse group of molecules commonly known as "quats". More specifically,
chlormequat chloride has been classified according to the Agency's PR
Notice 88-2 (February 26, 1988) as a Group I, alkyl or hydroxyalkyl
(straight chain) substituted quaternary ammonium compounds. Another
Group I quaternary ammonium salt, didecyldimethylammonium chloride
(DDAC) was recently reregistered by the Antimicrobials Division (USEPA
D325481, 2006). The quaternary ammonium cations are permanently charged,
independent of the pH of solution.

Chlormequat chloride is expected to be moderately mobile to mobile (FAO
classification scheme) in the environment. The major route of
dissipation in the environment appears to be microbial degradation in
both soil and aquatic systems. There is uncertainty regarding
chlormequat chloride's persistence in the environment.

### Pesticide Type, Class, and mode of Action

#### Chemical Profile

Chemical name: 2-chloro-N,N,N-trimethylethylethanammonium chloride salt

Common name: Chlormequat chloride

Chlorocholine chloride (CCC)

CAS No. 000999-81-5

Chemical structure:

![](media/image4.wmf){width="2.0104166666666665in"
height="1.0138888888888888in"}

#### Mode of Action 

Chlormequat chloride is used as a plant growth regulator (PGR), reducing
internodal elongation and delaying flowering. The physiological causes
of these effects on the plant are not well documented.

### Usage Overview

Chlormequat chloride is currently registered for application to
greenhouse ornamentals. The first outdoor use of this chemical was
registered in November, 2006; therefore there are no available data on
current usage for this risk assessment.

## B. Receptors {#b.-receptors .unnumbered}

Ecological effect endpoints are derived from registrant-submitted
guideline studies as required for registration under the Federal
Insecticide, Fungicide and Rodenticide Act (FIFRA; 40 CFR Part 158), as
well as a review of data available through acceptable open literature
(ECOTOX; www.epa.gov/ecotox), when available. The most sensitive
endpoints (described below) from testing of surrogate species are used
to estimate risk to the taxonomic group(s) represented by the surrogate
tested. Toxicity data reported in this document are intended to
represent all terrestrial and aquatic organisms. However, only a few
surrogate species for both freshwater fish and birds are used to
represent all freshwater fish (2000+) and bird (680+) species in the
United States. In addition, neither reptiles nor amphibians are tested.
Birds are used as surrogates for reptiles and terrestrial-phase
amphibians; fish are used as surrogates for aquatic-phase amphibians.
The Norway rat is typically the surrogate for all mammals.

## C. Assessment Endpoints {#c.-assessment-endpoints .unnumbered}

Assessment endpoints are defined, per Agency guidelines, as "explicit
expressions of the actual environmental value that is to be protected"
which are "operationally defined by an ecological entity and its
attributes" (USEPA, 2004). The ecological entity can be a species, a
functional group of species, a community, an ecosystem, or another
entity of importance or concern. An attribute is the characteristic of
the entity that is important to protect and is potentially at risk.

Defining an assessment endpoint involves two steps: 1) identifying the
valued attributes of the environment that are considered to be at risk,
and 2) operationally defining the assessment endpoint in terms of an
ecological entity (*e.g.*, a community of fish and aquatic
invertebrates) and its attributes (*i.e*., survival and reproduction).
Therefore, selection of the assessment endpoints is based on valued
entities (*i.e.*, ecological receptors), the ecosystems potentially at
risk and the routes by which ecological receptors are exposed to
pesticide-related contamination. The selection of clearly defined
assessment endpoints is important because they provide direction and
boundaries in the risk assessment for addressing risk management issues
of concern.

Typical assessment endpoints for screening-level pesticide ecological
risk assessments include reduced survival and/or reproductive impairment
for both aquatic and terrestrial animal species from direct acute or
direct chronic exposures. Aquatic animal groups that are typically
characterized in the risk assessment include: freshwater fish and
invertebrates and estuarine/marine fish and invertebrates. Terrestrial
animal groups include birds, mammals, and beneficial insects. All
assessment endpoints are characterized at the individual level in order
to protect threatened and endangered species. However, risks to higher
biological levels (*i.e.*, populations and communities) can be inferred
from this approach (*e.g.*, pesticide effects on individual survival and
fecundity may impact population stability, growth, and/or habitat
carrying capacity). A species-specific assessment containing
characterization of indirect effects to listed species and critical
habitat is the next step following completion of the screening-level
risk assessment.

For terrestrial and semi-aquatic plants, the screening assessment
endpoint is the perpetuation of populations of non-target species (crops
and non-crop plant species). Existing testing requirements only evaluate
the seedling emergence and vegetative vigor of annuals. Although it is
recognized that the endpoints of seedling emergence and vegetative vigor
may not address all terrestrial and semi-aquatic plant life cycle
components, it is assumed that impacts on plant emergence and/or on
active growth have the potential to impact individual competitive
ability and reproductive success, from which population effects can be
inferred.

For aquatic plants, the assessment endpoint is the maintenance and
growth of standing crop or biomass. Measurement endpoints for this
assessment focus on nonvascular, *e.g.*, algae, and vascular plants,
*e.g.*, duckweed (*Lemna gibba*), growth rates and biomass measurements.

The ecological relevance of the assessment endpoints assumes that
complete exposure pathways exist for these receptors, that the receptors
may be sensitive to pesticides in affected media and/or forage items and
that the receptors could potentially inhabit areas where pesticides are
applied, or areas where runoff and/or spray drift may impact the sites
because suitable habitat is available.

Ecological measurement endpoints for this screening-level risk
assessment are based on a suite of registrant-submitted toxicity studies
performed on a limited number of organisms, supplemented by the open
literature where applicable, in the following broad groupings:

1.  Birds, *e.g.,* Japanese quail (*Coturnix coturnix japonica*) and
    mallard duck (*Anas platyrhynchos*), also used as surrogate species
    for terrestrial-phase amphibians and reptiles,

2.  Mammals, *e.g.*, laboratory rat (*Rattus norvegicus*),

3.  Freshwater Fish *e.g.*, rainbow trout (*Oncorhynchus mykiss*), also
    used as a surrogate for aquatic-phase amphibians,

4.  Freshwater invertebrates, *e.g.*, waterflea (*Daphnia magna*),

5.  Estuarine/marine fish,

6.  Estuarine/marine invertebrates,

7.  Terrestrial plants,

8.  Vascular and nonvascular aquatic plants.

Within each of these broad taxonomic groups, an acute and chronic
endpoint is selected from the available test data. The selection is made
from the most sensitive species tested within a particular surrogate
group. If additional toxicity data are available from other sources, the
selection of an endpoint may not be limited to the surrogate species
listed above, but may be expanded to include those data for other groups
or species that have been deemed of sufficient quality by the Agency for
use in the risk assessment.

## D. Conceptual Model  {#d.-conceptual-model .unnumbered}

In order for a chemical to pose an ecological risk, it must reach
ecological receptors in biologically significant concentrations.
Exposure pathways are defined as the means by which a contaminant moves
in the environment from a source to an ecological receptor. For an
ecological exposure pathway to be complete, it must have a source, an
environmental transport medium, a point of exposure for ecological
receptors, and a feasible route of exposure.

### 1. Diagram {#diagram .unnumbered}

The conceptual model used to depict the potential ecological risk
associated with the proposed use of chlormequat chloride (the stressor)
assumes that as a pesticide, chlormequat chloride can adversely affect
terrestrial and aquatic organisms (the receptors) if environmental
concentrations exceed toxic thresholds as a result of application
according to the label directions (Figure 1). Ecological receptors that
may potentially be exposed to chlormequat chloride include terrestrial
and semi-aquatic wildlife (*e.g.*, mammals, birds, amphibians and
reptiles), terrestrial and semi-aquatic plants, terrestrial
invertebrates (*e.g.*, honey bees), and terrestrial soil and aquatic
sediment invertebrates. Additionally, aquatic organisms (*i.e.*,
freshwater and estuarine/marine fish and invertebrates, amphibians, and
aquatic plants) are potential receptors in adjacent water bodies through
off-site transport of chlormequat chloride from the application site
through runoff, erosion and/or spray drift.

Routes of exposure to terrestrial and aquatic organisms can occur from
direct application, spray drift and/or runoff. Exposure may be through
ingestion of contaminated food or water sources, dermal contact or
absorption, and/or inhalation.

This assessment does not take into account potential atmospheric
transport in estimating environmental concentrations, potential exposure
via ground water, nor does it account for ingestion of chlormequat
chloride residues by animals in contaminated grit, ingestion through
preening activities, or uptake through inhalation or dermal absorption
by terrestrial animals. Exposure to terrestrial animals is based
primarily on dietary consumption of foliar (and insect) residues.
Aquatic assessments assume that all potential routes of direct exposure
are accounted for.

**Figure 1.** Conceptual Model for a Screening Level Assessment of
Chlormequat Chloride on Ornamental Crops.

### 2. Risk Hypothesis {#risk-hypothesis .unnumbered}

*The labeled outdoor uses of chlormequat chloride may pose risk of
adverse effects to nontarget species in the environment.*

Number range CHAPTERAt maximum application rates for the outdoor uses of
chlormequat chloride, exposure of terrestrial, aquatic and semi-aquatic
wildlife and plants to chlormequat chloride may be of sufficient
duration and intensity to result in direct effects (*e.g.*, mortality
due to acute exposure or impaired reproduction, growth, or survival from
chronic exposure). Additionally, species may be indirectly affected by
chlormequat chloride due to a loss of food resources and/or changes to
ecologically critical habitat resulting from proposed uses.

## E. Analysis Plan {#e.-analysis-plan .unnumbered}

The maximum outdoor label application rates for use of chlormequat
chloride on bedding plants and containerized ornamentals were selected
for modeling environmental concentrations for this screening-level
deterministic (risk-quotient based) assessment, as the outdoor uses
represent the greatest likelihood of non-target exposure. The most
sensitive toxicity endpoints from surrogate test species are used to
estimate treatment-related effects on growth and survival assessment
endpoints. Estimated environmental concentrations (EECs) used in
terrestrial and aquatic ecological risk assessments are based solely on
chlormequat chloride parent compound.

A risk quotient-based approach is used in this assessment, comparing the
ratio of exposure concentrations to effects endpoints with predetermined
levels of concern (LOCs). The use, laboratory environmental fate, and
laboratory ecological effects data, all of which provide the basis for
these risk quotients, are characterized in the assessment. Although risk
is often defined as the likelihood and magnitude of adverse ecological
effects, the risk quotient-based approach does not provide a
quantitative estimate of likelihood and/or magnitude of an adverse
effect. At a screening level, RQs that fall below the Agency's LOC (for
a given taxon) indicate a low potential for risk, while RQs greater than
the LOC indicate there is a potential for ecological effects if a
sufficient exposure threshold is reached.

# Analysis

## Use Characterization

Chlormequat chloride is a plant growth regulator (PGR) for use on
bedding plants and containerized ornamentals in shadehouses and
nurseries as the formulated product Cycocel® (EPA Reg. No. 241-74). In
open production areas not under cover, Cycocel^®^ use is restricted to
bedding plants and containerized ornamentals. Application to field-grown
ornamentals is not allowed by the label. The label allows foliar spray
applications and drench applications. Drench applications are only
allowed for the indoor greenhouse uses. This assessment does not
evaluate the indoor greenhouse uses because environmental exposures are
expected to be limited to greenhouse discharge which is regulated under
the National Pollutant Discharge Elimination System (NPDES). The
registrant stated that a majority of the outdoor uses of chlormequat
chloride would be in tank mix with B-nine^®^ (daminozide; 035101), which
provides greater PGR effect than either product alone (Latimer *et al*.,
2001). Potential synergistic effects are not considered in this risk
assessment, as there is no available ecological effects data on the
possible tank mixes.

For the outdoor (shadehouse and nursery) uses, spray volume providing
thorough plant coverage will vary with plant size and foliage coverage
and application rates will vary according specific plant species.
However, the label states that a single application cannot exceed a rate
of 3.7 lbs. ai/A, and the total annual rate can not exceed 33.3 lbs
ai/A/year. The label also limits the number of applications to 3 per
crop cycle. For this assessment, 3 production cycles per year are
considered, resulting in a maximum of 9 applications per year. The
interval between repeat applications to the same crop can range from 5
to 21 days. The proposed label also states that applications by
mechanical (tractor) multi-nozzle sprayers may not exceed one acre of
plants per day, per mixer/loader/applicator. **Table 2** summarizes the
maximum application rates used in this assessment. This assessment also
assumes that chlormequat chloride will be applied by low-boom sprayer to
bedding plants and by backpack sprayer to most containerized
ornamentals.

[]{.mark}

**Table 2.** Proposed maximum use patterns of chlormequat chloride.

  --------------- ------------- ----------- ----------- ------------ ----------
  **Uses**        **App. Type** **Max       **Max \# of **Max annual **Min app.
                                single app. app./       app. Rate    Interval
                                rate (lbs   year**      (lbs         (days)**
                                ai/A)**                 ai/A/yr)**   

  Bedding plants, Foliar spray; 3.7         9           33.3         5
  containerized   mechanized                                         
  ornamentals     ground boom                                        
                  sprayer                                            
  --------------- ------------- ----------- ----------- ------------ ----------

[]{.mark}

The USDA National Agriculture Statistics Service (NASS, 2006), which
collects information on, among other things, the numbers of farms and
acreages associated with agricultural practices, has 2002 statistics for
\"nursery, greenhouse, floriculture, mushrooms, sod, and vegetable seeds
grown for sale\". This category is further divided into "under glass or
other protection" acres and "in the open". While it is not possible to
determine the actual area likely to be treated with chlormequat
chloride, the "in the open" category can provide a useful index of
potential use area. According to NASS, California (18,600 acres) and
Florida (12,800 acres) dominate the category, with only two other states
(Michigan and New Jersey) having more than 3,000 acres. However, all 50
states report at least some acreage in this category.

## Exposure Characterization

### Environmental Fate and Transport Characterization

There are a number of data gaps in the chlormequat chloride
environmental fate and transport dataset. In the absence of data,
assumptions made regarding chlormequat chloride were compared to and
supported by the environmental fate and transport data of DDAC (PC code
69149, CAS No. 007173-51-5). DDAC and chlormequat chloride are both
quaternary ammonium compounds that have been classified according to the
Agency's PR Notice 88-2 (February 26, 1988) as Group I, alkyl or
hydroxyalkyl (straight chain) substituted quaternary ammonium compounds.
Details of the environmental fate and transport studies can be found in
Appendix I.

Chlormequat chloride has variable mobility in the environment. Batch
equilibrium studies resulted in Freundlich sorption coefficients ranging
1.13 -- 9.12 ml/g with corresponding 1/N values ranging 0.511 -- 0.955
(MRIDs 46715228, 46715229). Even though chlormequat chloride is a
cation, the correlation between cation exchange capacity (CEC) and
sorption was not significant in the batch equilibrium studies.
Chlormequat chloride is classified as moderately mobile to mobile,
according to the FAO classification scheme. In an aged column leaching
study 0.3-0.5 % of the applied radioactivity was found in the leachate
after 48 hours of leaching with 4 pore volumes of 0.01 M CaCl~2~ in a
loamy sand soil (MRID 46715230). In another aged column leaching study
2.5% of the applied radioactivity was found in the leachate following 45
days of leaching with 0.5 inches of distilled water daily through a
15-inch column filled with a clay loam soil (MRID 124061). In an unaged
column leaching study \< 0.1 % of applied radioactivity was found in the
leachate after leaching with 20 inches of distilled water at a rate not
exceeding 1 inch/hour through a 15 inch column filled with a sand, sandy
loam, silt loam and clay loam soil (MRID 124062). In both of these
studies distilled water was used which could lead to dispersion of clays
that could affect soil structure. Depending on soil, site and
meteorological conditions chlormequat chloride may be transported
off-site via runoff, leaching and/or erosion.

Overall, the major route of dissipation for chlormequat chloride appears
to be microbial degradation. An aerobic soil metabolism study showed
that chlormequat chloride degraded with half-lives of 30-43 d in two
sandy loam and two silt loam soils (MRID 46715225). Soils were was
sequentially extracted four times with methanol:water, then four times
with acidified water (pH 2). Nonextractable residues increased from
0.9-6.0% at day 0 to 19.0-27.8% at 112 days. In the study, up to 43.7%
and 10.7% of the applied radioactivity in the soil extracts was
unaccounted for in two soils. No attempt was made to identify these
transformation products and it is not known whether or not the residues
consisted of one or more components. Consequently, all transformation
products detected at \>10% of the applied may not have been identified.
Using a total residue approach that assumes all unidentified extractable
residues are of equal toxicity to chlormequat chloride results in
half-lives of 32 -- 132 days.

An aerobic aquatic metabolism study showed that chlormequat chloride
degraded with total system half-lives of 5-9 days in a river water-sandy
loam sediment and pond water-silt loam sediment system (MRID 46715227).
Even though sediments were sequentially extracted 1-3 times with
methanol:acidified (pH 2) water, followed by 1-5 times with acidic (pH
2) water, nonextractable residues increased from 1.0-2.6% at time 0 to
49.0-59.2% at 30 days and were 27.7-31.3% at 105 study termination. The
nonextractable residues are uncharacterized and it is uncertain whether
or not they consist of parent chlormequat chloride and/or residues of
risk concern.

There were no available acceptable data for degradation of chlormequat
chloride by hydrolysis or photolysis. Comparison to DDAC data, however,
suggests that chlormequat chloride may be hydrolytically and
photolytically stable (MRID 411758-01, 411758-02). There are also no
data for chlormequat chloride under anaerobic conditions. DDAC has,
however, been shown to be persistent under anaerobic conditions (MRID
422538-02). **Table 3** summarizes the registrant-submitted
environmental fate and transport properties of chlormequat chloride.

Major degradates (excluding CO~2~) were not identified in the available
metabolism studies. In the aerobic aquatic metabolism study, an
unidentified polar compound reached a maximum of 4.8 and 13.4 % in the
total systems. Choline-chloride was also detected in the aerobic aquatic
metabolism study at a maximum of 2.0 and 5.5% in the total systems.

**Table 3.** Summary of environmental chemistry and fate properties of
chlormequat chloride.

+---------------------+----------+----+----+-----+-------------------+
| **Parameter**       | *        |    |    |     | **Ref             |
|                     | *Value** |    |    |     | erence/Comments** |
+=====================+==========+====+====+=====+===================+
| ***Selected         |          |    |    |     |                   |
| Physical/Chemical   |          |    |    |     |                   |
| Parameters***       |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| PC code             | 018101   |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| CAS No.             | 999-81-5 |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Physical state      | Liquid   |    |    |     | Product chemistry |
+---------------------+----------+----+----+-----+-------------------+
| Chemical name       | 2-       |    |    |     | Product chemistry |
|                     | chloro-N |    |    |     |                   |
|                     | ,N,N-tri |    |    |     |                   |
|                     | methylet |    |    |     |                   |
|                     | hylethan |    |    |     |                   |
|                     | ammonium |    |    |     |                   |
|                     | chloride |    |    |     |                   |
|                     | salt     |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Chemical formula    | C~5~H~1  |    |    |     | Product chemistry |
|                     | 3~Cl~2~N |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Molecular weight    | 158.1    |    |    |     | Product chemistry |
|                     | g/mol    |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Water solubility    | 10^6^    |    |    |     | Product chemistry |
|                     | mg/L     |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Density             | 1.14     |    |    |     | Product chemistry |
|                     | g/mL     |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Boiling point       | Not      |    |    |     | Product chemistry |
|                     | reported |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Vapor pressure (20  | 7.5 x    |    |    |     | Product chemistry |
| °C)                 | 10^-8^   |    |    |     |                   |
|                     | mm Hg    |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| log K~OW~           | 2.51     |    |    |     | Product chemistry |
+---------------------+----------+----+----+-----+-------------------+
| ***Persistence***   |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Hydrolysis t~1/2~   |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| pH 5                | No data  |    |    |     |                   |
|                     |          |    |    |     |                   |
| pH 7                |          |    |    |     |                   |
|                     |          |    |    |     |                   |
| pH 9                |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Photolysis t~1/2~in | No data  |    |    |     |                   |
| water               |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Photolysis t~1/2~   | No data  |    |    |     |                   |
| in soil             |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Soil metabolism     | 43.4,    |    |    |     | MRID 46715225     |
| aerobic t~1/2~      | 29.7,    |    |    |     |                   |
|                     | 31.5,    |    |    |     |                   |
| \[Total             | 43.0 d   |    |    |     |                   |
| residues\]^1^       |          |    |    |     |                   |
|                     | \[43.4,  |    |    |     |                   |
|                     | 32.9,    |    |    |     |                   |
|                     | 36.3,    |    |    |     |                   |
|                     | 132.3    |    |    |     |                   |
|                     | d\]      |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Soil metabolism     | No data  |    |    |     |                   |
| anaerobic t~1/2~    |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Aquatic metabolism  | 4.9, 8.7 |    |    |     | MRID 46715227     |
| aerobic t~1/2~      | d        |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Aquatic metabolism  | No data  |    |    |     |                   |
| anaerobic t~1/2~    |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| ***Mobility***      |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Batch equilibrium   | Soil     | K  | 1  | K~  | MRIDs 46715228,   |
|                     | Type     | ~f | /N | oc~ | 46715229          |
|                     |          | ~^ |    | ^3^ |                   |
|                     |          | 2^ |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Loamy    | 1. | 0  | 55  |                   |
|                     | sand     | 25 | .5 |     |                   |
|                     |          |    | 11 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Sandy    | 4. | 0  | 291 |                   |
|                     | loam     | 57 | .6 |     |                   |
|                     |          |    | 91 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Silt     | 1. | 0  | 81  |                   |
|                     | loam     | 13 | .7 |     |                   |
|                     |          |    | 02 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Sand     | 1. | 0  | 93  |                   |
|                     |          | 73 | .5 |     |                   |
|                     |          |    | 43 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Sandy    | 2. | 0  | 89  |                   |
|                     | loam     | 14 | .7 |     |                   |
|                     |          |    | 68 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Loam     | 9. | 0  | 912 |                   |
|                     |          | 12 | .8 |     |                   |
|                     |          |    | 49 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     | Silt     | 8. | 0  | 385 |                   |
|                     | loam     | 08 | .9 |     |                   |
|                     |          |    | 55 |     |                   |
+---------------------+----------+----+----+-----+-------------------+
|                     |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Column leaching --  | 0.3-0.5  |    |    |     | MRID 46715230,    |
| aged residues       | %        |    |    |     | AN124061          |
|                     | applied  |    |    |     |                   |
|                     | radio    |    |    |     |                   |
|                     | activity |    |    |     |                   |
|                     | in       |    |    |     |                   |
|                     | leachate |    |    |     |                   |
|                     | after 48 |    |    |     |                   |
|                     | hours of |    |    |     |                   |
|                     | leaching |    |    |     |                   |
|                     | with 4   |    |    |     |                   |
|                     | pore     |    |    |     |                   |
|                     | volumes  |    |    |     |                   |
|                     | of 0.01  |    |    |     |                   |
|                     | M        |    |    |     |                   |
|                     | CaCl~2~  |    |    |     |                   |
|                     | in a     |    |    |     |                   |
|                     | loamy    |    |    |     |                   |
|                     | sand     |    |    |     |                   |
|                     | soil;    |    |    |     |                   |
|                     |          |    |    |     |                   |
|                     | 2.5% of  |    |    |     |                   |
|                     | applied  |    |    |     |                   |
|                     | radio    |    |    |     |                   |
|                     | activity |    |    |     |                   |
|                     | in       |    |    |     |                   |
|                     | leachate |    |    |     |                   |
|                     | f        |    |    |     |                   |
|                     | ollowing |    |    |     |                   |
|                     | 45 days  |    |    |     |                   |
|                     | of       |    |    |     |                   |
|                     | leaching |    |    |     |                   |
|                     | with 0.5 |    |    |     |                   |
|                     | inches   |    |    |     |                   |
|                     | of       |    |    |     |                   |
|                     | d        |    |    |     |                   |
|                     | istilled |    |    |     |                   |
|                     | water    |    |    |     |                   |
|                     | daily in |    |    |     |                   |
|                     | 15 inch  |    |    |     |                   |
|                     | column   |    |    |     |                   |
|                     | with a   |    |    |     |                   |
|                     | clay     |    |    |     |                   |
|                     | loam     |    |    |     |                   |
|                     | soil;    |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Column leaching -   | \< 0.1 % |    |    |     | AN124062          |
| unaged              | of       |    |    |     |                   |
|                     | applied  |    |    |     |                   |
|                     | radio    |    |    |     |                   |
|                     | activity |    |    |     |                   |
|                     | in       |    |    |     |                   |
|                     | leachate |    |    |     |                   |
|                     | after    |    |    |     |                   |
|                     | leaching |    |    |     |                   |
|                     | with 20  |    |    |     |                   |
|                     | inches   |    |    |     |                   |
|                     | of       |    |    |     |                   |
|                     | d        |    |    |     |                   |
|                     | istilled |    |    |     |                   |
|                     | water in |    |    |     |                   |
|                     | 15 inch  |    |    |     |                   |
|                     | column   |    |    |     |                   |
|                     | with a   |    |    |     |                   |
|                     | sand,    |    |    |     |                   |
|                     | sandy    |    |    |     |                   |
|                     | loam,    |    |    |     |                   |
|                     | silt     |    |    |     |                   |
|                     | loam and |    |    |     |                   |
|                     | clay     |    |    |     |                   |
|                     | loam     |    |    |     |                   |
|                     | soil.    |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Laboratory          | NA       |    |    |     |                   |
| volatility          |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| ***Field            |          |    |    |     |                   |
| Dissipation***      |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Terrestrial field   | No data  |    |    |     |                   |
| dissipation         |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Aquatic field       | NA       |    |    |     |                   |
| dissipation         |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| **                  |          |    |    |     |                   |
| *Bioaccumulation*** |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+
| Accumulation in     | No data  |    |    |     |                   |
| fish, BCF           |          |    |    |     |                   |
+---------------------+----------+----+----+-----+-------------------+

1\. Total residue approach assumes uncharacterized extractable residues
are of similar toxicity as parent chlormequat chloride.

2\. Units of (mg/kg)/(mg/L)^1/N^, where 1/N is the Freundlich exponent.

3\. Approximation calculated from the Freundlich coefficient, per
standard EFED guidance.

### Aquatic Exposure

Number range CHAPTERTier II modeling for selected scenarios representing
proposed outdoor uses was used to generate estimated environmental
concentrations (EECs). No monitoring data were available for the
proposed new uses of chlormequat chloride. For Tier II, two models are
used in tandem: the Pesticide Root Zone Model, (PRZM, Carsel *et al*.,
1997) and the Exposure Analysis Modeling System (EXAMS, Burns, 1997).
PRZM (3.12 beta dated May 24, 2001) simulates fate and transport on the
agricultural field, and EXAMS (2.98.04, dated July 18, 2002) simulates
the fate and resulting daily concentrations in the water body.
Simulations are carried out with the linkage program shell, PE4V01.pl
(dated 8/13/2003), which incorporates the standard crop and orchard
scenarios developed by EFED. Simulations are run for multiple (usually
30) years, and the EECs represent peak values that are expected once
every ten years based on the thirty years of daily values generated
during the simulation. Additional information on these models can be
found at:
[[http://www.epa.gov/oppefed1/models/water/index.htm]{.underline}](http://www.epa.gov/oppefed1/models/water/index.htm).

For aquatic endpoints, the exposure is estimated for the maximum
application pattern to a 10-ha field bordering a 1-ha pond, 2-m deep
(20,000 m^3^) with no outlet. Exposure estimates generated using this
standard pond are intended to represent a wide variety of vulnerable
water bodies that occur at the top of watersheds including prairie pot
holes, playa lakes, wetlands, vernal pools, man-made and natural ponds,
and intermittent and first-order streams. As a group, there are factors
that make these water bodies more or less vulnerable than the standard
surrogate pond. Static water bodies that have larger ratios of
pesticide-treated drainage area to water body volume would be expected
to have higher peak EECs than the standard pond. These water bodies will
be either smaller in size or have large drainage areas. Smaller water
bodies have limited storage capacity and thus may overflow and carry
pesticide in the discharge, whereas the standard pond has no discharge.
As watershed size increases beyond 10-ha, it becomes increasingly
unlikely that the entire watershed is planted with a non-major single
crop that is all treated simultaneously with the pesticide. Headwater
streams can also have peak concentrations higher than the standard pond,
but they likely persist for only short periods of time and are then
carried and dissipated downstream.

OPP standard PRZM crop or orchard scenarios, which consist of
location-specific soils, weather, and cropping practices, are used in
the simulations to represent proposed labeled uses of Cycocel^®^. These
scenarios are developed to represent high-end exposure sites in terms of
vulnerability to runoff and erosion and subsequent off-site transport of
pesticide. Cycocel^®^ is being proposed for use on containerized
ornamentals and bedding plants in nurseries and shade houses. There are
currently no PRZM scenarios for these containerized uses. For use on
ornamental trees, the applications will be likely applied by hand-held
equipment (*e.g.*, backpack sprayer). Although residues may be washed
from foliage following backpack sprayer application, the controlled and
directed nature of this type of application would likely minimize both
excess mass applied and spray drift. Therefore off-site transport
resulting from these applications was not considered an exposure pathway
for this assessment. It is assumed that applications made by
tractor-pulled equipment will be limited to bedding plants. It is
assumed that the EECs resulting from the tractor-pulled spray
applications will be more conservative of applications made by hand-held
equipment.

Because no specific nursery scenario has been developed, FL turf and PA
turf were chosen as surrogate scenarios for the bedding plant use. The
turf scenarios were chosen as surrogates because they consist of high
organic matter top soil layers (designed to approximate a thatch layer
in turf) that may be similar to soils used for bedding plants in
nurseries. Additionally, the FL turf scenario results in the greatest
upper-bound EECs because it is in a high rainfall area (1216 mm 30-year
mean annual precipitation). However, the extent to which the
meteorological and agronomic characteristics of the surrogate scenarios
are representative of actual use sites in nurseries is uncertain. A
summary of the crop scenarios used to estimate chlormequat chloride
concentrations in the aquatic systems for ecological risk assessment are
listed in **Table 4**.

Table 4. Summary of crop scenarios used in aquatic exposure modeling.

+-----------------+---------------+--------------+---------------------+
| **Cycocel Use** | **Crop        | **MLRA/ Met  | **Scenario          |
|                 | Scenario**    | Station**    | Characterization**  |
+=================+===============+==============+=====================+
| Bedding plant   | **FL turf**:  | MLRA 156A;   | Surrogate for       |
|                 | Osceola       | W12834       | bedding plants in   |
|                 | County,       |              | southeast           |
|                 |               |              |                     |
|                 | Adamsville    |              |                     |
|                 | sand          |              |                     |
+-----------------+---------------+--------------+---------------------+
|                 | **PA turf**:  | MLRA 148;    | Surrogate for       |
|                 | York County,  | W14737       | bedding plants in   |
|                 |               |              | mid-Atlantic        |
|                 | Glenville     |              |                     |
|                 | silt loam     |              |                     |
+-----------------+---------------+--------------+---------------------+

Number range CHAPTERPRZM/EXAMS modeling was done using the proposed
maximum label rate, maximum number of applications per year and the
minimum application interval. Input parameters are listed in **Table
5**. Pesticide applications were simulated as foliar applications (PRZM
chemical application method, CAM = 2), with an application efficiency
and drift fractions equal to 0.99 and 0.01, respectively. The condition
for disposition of the pesticide remaining on foliage after harvest
(PRZM variable IPSCND) was set to 1 (pesticide remaining on foliage is
converted to surface application), as a protective assumption. The first
date of application was chosen to be in early spring (April 15^th^),
although applications are expected anytime throughout the year.

Based on registrant-submitted data for chlormequat chloride, an aerobic
soil metabolism and aerobic aquatic metabolism half-life of 100 and 12.6
d (the upper 90^th^ percentile confidence bound on the mean),
respectively, were used for surface water modeling with PRZM/EXAMS. It
was assumed that chlormequat chloride is stable to photolysis,
hydrolysis, and anaerobic metabolism since there are no acceptable data
for these parameters. A soil organic carbon partitioning coefficient
(K~oc~) of 272 ml/g~oc~, the mean of seven soils, was used.

**Table 5.** PRZM/EXAMS input parameters for chlormequat chloride
applied by ground spray

+---------------------+------+----------------+-----------------------+
| **Input Parameter** | *    | **Source**     | **Comment**           |
|                     | *Val |                |                       |
|                     | ue** |                |                       |
+=====================+======+================+=======================+
| Application Rate in | 3.7  | EPA Reg. No.   |                       |
|                     | (4   | 241-74         |                       |
| lbs a.i./A (kg      | .15) |                |                       |
| a.i./ha)            |      |                |                       |
+---------------------+------+----------------+-----------------------+
| Applications per    | 9    | EPA Reg. No.   | 3 applications per    |
| Year                |      | 241-74         | crop production; 3    |
|                     |      |                | crop productions per  |
|                     |      |                | year                  |
+---------------------+------+----------------+-----------------------+
| Application         | 5    | EPA Reg. No.   |                       |
| Intervals (d)       |      | 241-74         |                       |
+---------------------+------+----------------+-----------------------+
| Date of Initial     | A    |                |                       |
| Application         | pril |                |                       |
|                     | 15   |                |                       |
+---------------------+------+----------------+-----------------------+
| Chemical            | 2    | EPA Reg. No.   | Foliar application    |
| Application Method  |      | 241-74         |                       |
| (CAM)               |      |                |                       |
+---------------------+------+----------------+-----------------------+
| IPSCND Input        | 1    |                |                       |
+---------------------+------+----------------+-----------------------+
| Spray Drift         | 0.01 | Input          | Ground spray default  |
| Fraction            |      | parameter      |                       |
|                     |      | guidance.^1^   |                       |
+---------------------+------+----------------+-----------------------+
| Application         | 0.99 | Input          | Ground spray default  |
| Efficiency          |      | parameter      |                       |
|                     |      | guidance.^1^   |                       |
+---------------------+------+----------------+-----------------------+
| Molecular Mass      | 1    | Product        |                       |
| (g/mol)             | 58.1 | chemistry      |                       |
|                     |      | data.          |                       |
+---------------------+------+----------------+-----------------------+
| Vapor Pressure      | 7.5  | Product        |                       |
| (Torr)              | x    | chemistry      |                       |
|                     | 10   |                |                       |
|                     | ^-8^ |                |                       |
+---------------------+------+----------------+-----------------------+
| Henry\'s Law        | 1.6  | Calculated     |                       |
| Constant            | x10^ |                |                       |
| (atm-m^3^/mol)      | -15^ |                |                       |
+---------------------+------+----------------+-----------------------+
| Solubility in Water | 1    | Product        | Not multiplied by 10  |
| at 25^o^C (mg/L)    | 0^6^ | chemistry      |                       |
|                     |      | data.          |                       |
+---------------------+------+----------------+-----------------------+
| Organic             | 272  | MRIDs          | mean of seven         |
| Carbon-Water        |      | 46715228,      | values.^1^            |
| Partition           |      | 46715229       |                       |
| Coefficient (K~oc~, |      |                |                       |
| ml/g~oc~)           |      |                |                       |
+---------------------+------+----------------+-----------------------+
| Aerobic Soil        | 100  | MRID 46715225  | 90^th^ percentile     |
| Metabolism t~1/2~   |      |                | upper confidence      |
| (d)                 |      |                | bound on the mean     |
|                     |      |                | (43.4, 32.9, 36.3,    |
|                     |      |                | 132.3 d), based on    |
|                     |      |                | total residues^2^     |
+---------------------+------+----------------+-----------------------+
| Aerobic Aquatic     | 12.6 | MRID 46715227  | 90^th^ percentile     |
| Metabolism t~1/2~   |      |                | upper confidence      |
| (d)                 |      |                | bound on the mean     |
|                     |      |                | (4.9, 8.7 d)          |
+---------------------+------+----------------+-----------------------+
| Anaerobic Aquatic   | 0    | MRID 422538-02 | stable                |
| Metabolism t~1/2~   |      |                |                       |
| (d)                 |      |                |                       |
+---------------------+------+----------------+-----------------------+
| Hydrolysis t~1/2~   | 0    | MRID 411758-01 | stable                |
| (d)                 |      |                |                       |
+---------------------+------+----------------+-----------------------+
| Aqueous Photolysis  | 0    | MRID 411758-02 | stable                |
| t~1/2~ (d)          |      |                |                       |
+---------------------+------+----------------+-----------------------+
| 1\. EFED input      |      |                |                       |
| parameter guidance  |      |                |                       |
| is located at:      |      |                |                       |
| <http://www.        |      |                |                       |
| epa.gov/oppefed1/mo |      |                |                       |
| dels/water/input_gu |      |                |                       |
| idance2_28_02.htm>. |      |                |                       |
|                     |      |                |                       |
| 2\. Total residue   |      |                |                       |
| approach assumes    |      |                |                       |
| all unidentified    |      |                |                       |
| extractable         |      |                |                       |
| residues are of     |      |                |                       |
| similar toxicity to |      |                |                       |
| parent chlormequat  |      |                |                       |
| chloride.           |      |                |                       |
+---------------------+------+----------------+-----------------------+

The EECs listed in **Table 6** reflect maximum 1-in-10 year upper-bound
surface water concentrations based on the proposed maximum use rates for
containerized ornamentals and bedding plants where ground spray
applications are used.

[]{.mark}

**Table 6.** Tier II surface water 1-in-10-year estimated environmental
concentrations (EECs) of chlormequat chloride from containerized nursery
use (ppb).

  -----------------------------------------------------------------------------------
  **PRZM           **App. Rate (lbs  **Peak**   **4-day**   **21-day**   **60-day**
  ScenarioNumber   ai/A/yr)**                                            
  range CHAPTER**                                                        
  ---------------- ----------------- ---------- ----------- ------------ ------------
  FL turf          33.3              153        140         110          59

  PA turf          33.3              144        135         93           55
  -----------------------------------------------------------------------------------

### Terrestrial Exposure

#### Animals

Terrestrial wildlife exposure estimates are typically calculated for
birds and mammals emphasizing a dietary uptake of pesticide through
residues on vegetative and insect forage items. Avian terrestrial EECs
are considered representative of potential exposure for
terrestrial-phase amphibians and reptiles as well, unless more
appropriate data are available through ECOTOX. For exposure to
terrestrial organisms, pesticide residues on food items are estimated,
based on the assumption that organisms are exposed to a single pesticide
residue in a given exposure scenario. Exposure was evaluated using EECs
generated from a spreadsheet-based screening model (TREX v.1.2.3) that
calculates the dissipation of a chemical applied to foliar surfaces for
single or multiple applications. The terrestrial animal exposure
assessment is based on the methods of Hoerger and Kenaga (1972) as
modified by Fletcher *et al.* (1994). When data are absent, as in this
case, EFED assumes a 35-day foliar dissipation half life. The predicted
maximum residues of chlormequat chloride that may be expected to occur
on selected avian or mammalian food items immediately following
application at the maximum rate for a single growing cycle are presented
in **Table 7**. Since three growing cycles per year are permitted by the
label, these residues do not represent the maximum mass of chlormequat
chloride potentially available for wildlife exposure on an annual basis.
However, since new target plants would be present for each growing
cycle, only non-target, presumably marginal forage items, such as weeds,
would be potentially subject to multiple growing cycles. Further details
of the model are presented in **Appendix III**.

**Table 7.** Dietary-based estimated environmental concentrations (EECs)
on terrestrial animal forage items following applications of chlormequat
chloride to a single growing cycle of ornamentals based on TREX (version
1.2.3).

+---------------+---------------------+---------------+---------------+
| **Application | **Food Items**      | **Upper-bound | **Mean EEC**  |
| Rate**        |                     | EEC           |               |
|               |                     | (ppm)^a^**    | **(ppm)^a^**  |
+===============+=====================+===============+===============+
| 3.7 lbs ai/A  | Short grass         | 2421          | 857           |
|               |                     |               |               |
| 3             |                     |               |               |
| applications  |                     |               |               |
|               |                     |               |               |
| 5 day         |                     |               |               |
| interval      |                     |               |               |
+---------------+---------------------+---------------+---------------+
|               | Tall grass          | 1110          | 363           |
+---------------+---------------------+---------------+---------------+
|               | Broadleaf           | 1362          | 454           |
|               | plants/small        |               |               |
|               | insects             |               |               |
+---------------+---------------------+---------------+---------------+
|               | Fruits, pods,       | 151           | 71            |
|               | seeds, and large    |               |               |
|               | insects             |               |               |
+---------------+---------------------+---------------+---------------+

^a^ Predicted residues based on Hoerger and Kenaga (1972) as modified by
Fletcher et al. (1994).

#### Plants

Exposure to upland and wetland plants is estimated using the TerrPlant
(v1.2.1) screening model. TerrPlant estimates potential exposure from a
single application using default assumptions for runoff and spray drift
(**Table 8**). Multiple applications during a single growing cycle and
multiple growing cycles are not taken into account. See **Appendix IV**
for more information.

**Table 8. Expected environmental concentrations (EEC) on plants
following label-specified applications of chlormequat chloride
determined using the TerrPlant model (lbs ai/A).**

  ---------- --------------- -------------- ---------------- -----------------
  **Rate**   **Application   **Adjacent     **Adjacent       **Drift Only**
             Method**        Upland         Wetland          
                             Loading^a^**   Loading**        

  3.7 lbs    Ground Spray    0.22           1.89             0.04
  ai/A                                                       
  ---------- --------------- -------------- ---------------- -----------------

^a^Loading is runoff plus drift (lbs ai/A)

## Ecological Effects Characterization

In screening-level ecological risk assessments, the effects
characterization describes the types of effects a pesticide can
potentially produce in an animal or plant. This characterization is
generally based on registrant-submitted studies that describe acute and
chronic effects information for various aquatic and terrestrial animals
and plants; however, these data may also be supplemented by data
reported in ECOTOX that have met Agency criteria for acceptability.

Toxicity testing reported in this section does not include all species
of potentially affected by chlormequat chloride usage. Only a few
surrogate species for both freshwater fish and birds are used to
represent all freshwater fish (2000+) and bird (680+) species in the
United States. For mammals, toxicity studies are limited to the
laboratory rat. Also, neither reptiles nor amphibians are tested. The
risk assessment assumes that avian and reptilian and terrestrial-phase
amphibian toxicities are similar. Fish are considered reasonable
surrogates for aquatic-phase amphibians. Terrestrial plant data are
derived from the vegetative vigor and seedling emergence tests,
typically on 10 agricultural plant species, and do not account for
potential chronic or reproductive effects. Typically, five aquatic plant
species are used to represent potential toxicity to all aquatic plant
species.

### Aquatic Effects

#### Freshwater Fish

Two acceptable guideline studies with the bluegill sunfish (*Lepomis
macrochirus*; 001232-61) and rainbow trout (*Oncorhynchus mykiss*;
000374-33) indicate the 96-h median lethal concentration (LC~50~) is
\>1000 mg ai/L. One supplemental subacute 21-day toxicity study
following OECD 204 was reviewed (MRID 467152-17). The Agency has no
provision for subacute fish studies, but they provide supplemental
information useful in this risk assessment. In that study, rainbow trout
were exposed to chlormequat chloride concentrations of 43, 100, 250,
590, 1400 and 3400 mg/L. By the sixth day of the study (guideline acute
fish toxicity tests are 96h), 90% of the fish in the 3400 mg ai/L
concentration were dead. No other treatment-related mortalities were
observed. Therefore, the NOAEC for this study is 1400 mg ai/L and the
LC~50~ is \>1400 mg ai/L, which results in chlormequat chloride being
classified as practically non-toxic to freshwater fish on an acute
exposure basis. Additionally, ECOTOX reports LC~50~s of \>100 mg ai/L
for bluegill sunfish, fathead minnow (*Pimephales promelas*) and channel
catfish (*Ictalurus punctatus*), also resulting in chlormequat chloride
as being classified as practically nontoxic to freshwater fish. No
studies are available regarding chronic toxicity of chlormequat chloride
to freshwater fish.

#### Freshwater Invertebrates

A supplemental study assessing the acute toxicity of chlormequat
chloride to *Daphnia magna* (MRID 001387-19) indicates chlormequat
chloride is slightly toxic to freshwater invertebrates with an EC~50~ of
16.9 mg ai/L. In a 21-day chronic toxicity study on the water flea,
classified as supplemental, a NOAEC of 5.0 mg ai/L (MRID 467152-16) was
reported based on a statistically significant 20% reduction in live
offspring relative to the control.

#### Estuarine/Marine Fish

No acute or chronic studies regarding the toxicity of chlormequat
chloride to estuarine/marine fish were submitted by the registrant.
However, ECOTOX reports a study by Linden *et al.* (1979) which
established an LC~50~ for the bleak (*Alburnus alburnus*) at 1950 mg
ai/L, which results in chlormequat chloride being classified as
practically nontoxic to estuarine/marine fish on an acute exposure
basis. No chronic toxicity data for estuarine/marine fish are available
for this assessment.

#### Estuarine/Marine Invertebrates

No acute or chronic guideline studies regarding the toxicity of
chlormequat chloride to estuarine/marine invertebrates were available
for this assessment. However, ECOTOX reports a study by Linden *et al.*
(1979) which established an LC~50~ for the copepod *Nitocra spinipes* as
80 mg ai/L, which indicates chlormequat is slightly toxic to
estuarine/marine invertebrates on an acute exposure basis. No chronic
toxicity data for estuarine/marine invertebrates are available for this
assessment.

#### Aquatic Plants

Chlormequat is classified as moderately toxic to the aquatic vascular
plant *Lemna gibba* based on reductions in all measured parameters, the
most sensitive being frond number, with an EC~50~ of 2.8 mg ai/L and a
NOEC of 0.04 mg ai/L (MRID 467152-21). Chlormequat chloride is less
toxic to nonvascular plants such as green algae *Scenedesmus
subcapitatus* with a 96-hr EC~50~ \>899 mg ai/L and a NOAEC of 233 mg
ai/L (MRID 467152-22;) and blue-green algae (cyanobacteria; *Anabaena
flos-aquae*) with an EC~50~ \>207 mg ai/L and a NOAEC=207 mg ai/L (MRID
467152-23).

### Terrestrial Effects

#### Avian Acute Oral, Dietary and Chronic

The available data indicate that chlormequat chloride is slightly toxic
to avian species on an acute exposure basis. Two acute oral toxicity
studies, with the Japanese quail (*Coturnix coturnix japonica*)
indicated an LD~50~ of 556 mg ai/kg bw (MRID 467152-10) and 1018 mg ai/A
(MRID 467152-11;), respectively. In both studies, all mortalities
occurred in the first day of the 14-day studies. Chlormequat chloride is
slightly toxic (possibly) to practically nontoxic to Japanese quail
(LC~50~\>3175 mg ai/kg diet; MRID 467152-12) and the mallard duck
(LC~50~\>5438 mg ai/kg diet; MRID 467152-13) on a subacute dietary
exposure basis.

A supplemental avian reproduction study with the Japanese quail (MRID
467152-14) was submitted which had mean-measured concentrations of 158,
387 and 982 mg/kg diet. The study was conducted with a two week
pre-treatment period followed by a 6-week exposure period, rather than
the guideline 10-week pre-laying exposure followed by a 10-week
egg-laying exposure period. The most sensitive endpoints were the adult
parameters of food consumption and male body weight gain; both endpoints
showed significant adverse effects at all treatment levels. As a result,
the required NOAEC could not be statistically determined (\<158 mg ai/kg
diet) from this study. The most sensitive reproductive parameter was a
significant reduction in hatchlings per eggs set and number of cracked
eggs in the highest test concentration. Additionally, the study authors
reported that absolute testes weight was significantly reduced (by 16%)
in the 982 mg/kg group and that there was a significant increase in egg
shell thinning and decreased egg strength at the highest test
concentration. These reductions may reflect effects on
endocrine-mediated processes.

#### Mammalian Acute and Chronic

Mammalian toxicity studies are normally reviewed by the Health Effects
Division in support of the human health risk assessments conducted by
that division. However, they are also used to characterize the toxicity
to mammalian wildlife by EFED. The mammalian toxicity data (Norway rat
study; MRID 417216-04) indicate that chlormequat chloride is moderately
toxic to mammals on an acute oral exposure basis, with males (LD~50~=487
mg ai/kg bw) being slightly more sensitive than females (LD~50~=560 mg
ai/kg bw). In a two-generation study with Norway rats, there were
parental effects evident by decreased body weight at 255 mg ai/kg bw
(males again slightly more sensitive than females), with a NOAEL of 86.4
mg ai/kg bw (MRID 467152-06). Offspring effects (NOAEL=86.4 mg ai/kg bw)
were reduced mean litter size, body weight and delayed development

#### Non-target Insects

Chlormequat chloride is classified as practically nontoxic to honey bees
(*Apis mellifera*) on both an acute contact and acute oral basis
(LD~50~\>100 µg ai/bee; MRID 467152-24). No sublethal effects were
reported in the study.

#### Terrestrial Plants

A non-guideline seedling emergence test (MRID 467152-19) was submitted
for chlormequat chloride, with only six plants (4 dicot, 2 monocot)
tested, rather than the 10 species preferred in guideline studies.
Species tested were oat (*Avena sativa)*, onion (*Allium cepa*), carrot
(*Daucus carota*), oilseed rape (*Brassica napus*), soybean (*Glycine
max*) and sugar beet (*Beta vulgaris*). There were five treatment levels
and a control, with eight replicates per treatment, five seeds per
replicate. There was no effect at the highest treatment level (1.9 lbs
ai/A) for five of the six species. The percent emergence of the
dicotyledonous plant oilseed rape was significantly reduced by 38% at
the highest level tested, resulting in an EC~25~ of \>0.9 ai/A and a
NOEC of 0.9 lb ai/A.

A non-guideline vegetative vigor study (MRID 467152-20) was submitted
for chlormequat chloride, only six plants (4 dicot, 2 monocot) were
tested, rather than the 10 species preferred in guideline studies.
Species tested were oat, onion, carrot, pea (*Pisum sativum*), sunflower
(*Helianthus annuus*) and cabbage (*Brassica oleracea*). The study
design varied with species, but the treatment levels were 0.21, 0.42,
0.84, 1.7 and 3.4 lb ai/A for all species. The most sensitive species
was sunflower, with a calculated EC~25~ of 1.5 lb ai/A. A NOEC was not
determined due to significant reductions in fresh weight (biomass) at
all treatment levels (\>25% at the lowest treatment). Carrot biomass was
also effected, with an EC~25~ of 2.0 lbs ai/A and a NOEC of 0.21 lbs
ai/A. Although the EC~25~ for pea was \>3.4 lbs ai/A, there was a 20%
biomass reduction at 3.4 lbs ai/A, making the NOEC 1.7 lbs ai/A. The
other three species tested were unaffected at all treatment levels.

**Table 9.** Terrestrial plant toxicity endpoints used in RQ
calculations

  ---------------- --------------- ------------- ------------ ------------
  **Study Type**   **EC~25~**                    **NOAEC**    

                   **Mono**        **Dicot**     **Mono**     **Dicot**

  Seedling         \>1.9           \>0.9         1.9          0.9
  Emergence                                                   

  Vegetative Vigor \>3.4           1.5           3.4          \<0.21
  ---------------- --------------- ------------- ------------ ------------

### ECOTOX

The Agency's ECOTOX database
([www.epa.gov/ecotox](http://www.epa.gov/ecotox)) was reviewed for
toxicological endpoints. There were several reported terrestrial
studies; none were of greater sensitivity than those used in this
assessment. The estuarine/marine fish and invertebrate endpoints
reported above were selected from the ECOTOX report; no other reported
aquatic endpoints were more sensitive than those used in this
assessment.

# Risk Characterization

The risk quotient (RQ) approach is used in this assessment, comparing
the ratio of exposure concentrations to effects endpoints with
predetermined levels of concern (LOCs). Laboratory environmental fate,
laboratory ecological effects, and use data that provide the basis for
these risk quotients have been discussed previously in the assessment.
Although risk is often defined as the likelihood and magnitude of
adverse ecological effects, the risk quotient-based approach does not
provide a quantitative estimate of likelihood and/or magnitude of an
adverse effect. Estimated environmental concentrations (EECs) are
divided by acute and chronic toxicity values to calculate RQs. If the
RQs exceed the LOCs, the Agency presumes potential for risk to the taxa.
These LOCs (**Table 10**) are the Agency's interpretive policy and are
used to determine the need to consider regulatory action by indicating
whether a pesticide, used as directed on the label, has the potential to
cause adverse effects on non-target organisms.

**Table 10. Levels of concern (LOCs) for various taxa.**

  --------------------------------------------------------------------------------------
  **Risk                                **RQ**                                 **LOC**
  Presumption**                                                                
  --------------- --------------------- -------------------------------------- ---------
  Birds                                                                        

                  Acute Risk            EEC/LC~50~ or LD~50~/sqft or           0.5
                                        LD~50~/day                             

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

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

                  Chronic Risk          EEC/NOAEC                              1

  Wild Mammals                                                                 

                  Acute Risk            EEC/LC~50~ or LD~50~/sqft or           0.5
                                        LD~50~/day                             

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

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

                  Chronic Risk          EEC/NOAEC                              1

  Aquatic Animals                                                              

                  Acute Risk            EEC/LC~50~ or EC~50~                   0.5

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

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

                  Chronic Risk          EEC/NOAEC                              1

  Terrestrial and                                                              
  Semi-Aquatic                                                                 
  Plants                                                                       

                  Acute Risk            EEC/EC~25~                             1

                  Acute Endangered      EEC/NOAEC or EC~05~                    1
                  Species                                                      

  Aquatic Plants                                                               

                  Acute Risk            EEC/EC~50~                             1

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

## Risk Estimation

RQ values for the proposed use of chlormequat chloride on bedding and
containerized nursery plants indicate potential risk to aquatic and
terrestrial animals and plants. The acute and chronic toxicity endpoints
used in this risk assessment are summarized **Table 11**.

**Table 11.** The most sensitive endpoints used in the chlormequat
chloride risk assessment.

  ------------------------------------------------------------------------------------------------
  **Environment**   **Taxa**        **Type of **Type of    **Endpoint**   **Units**    **MRID**
                                    Risk**    Endpoint**                               
  ----------------- --------------- --------- ------------ -------------- ------------ -----------
  Aquatic           Fish            Acute     LC~50~       \>1400         mg ai/L      467152-17

  Freshwater                        Chronic   NOAEC        No data        \-           \-

                    Invertebrates   Acute     EC~50~       16.9           mg ai/L      001387-19

                                    Chronic   NOAEC        5              mg ai/L      467152-16

                    Plants          Acute     EC~50~       2.8            mg ai/L      467152-21

                                    Listed    NOAEC        0.04           mg ai/L      467152-21

  Terrestrial       Avian           Acute     LD~50~       556            mg ai/kg-bw  467152-10

                                    Chronic   NOAEC        \<158          mg           467152-14
                                                                          ai/kg-diet   

                    Mammalian       Acute     LD~50~       487            mg ai/kg-bw  417216-04

                                    Chronic   NOAEC        86.4           mg ai/kg-bw  467152-06

                    Plants          Acute     EC~25~       \>0.9          lb ai/A      467152-19

                                    Listed    NOAEC        0.9            lb ai/A      467152-20
  ------------------------------------------------------------------------------------------------

### Aquatic Species

#### Freshwater Fish

Because chlormequat chloride is classified as practically nontoxic to
freshwater fish, *i.e.* the LC~50~ is greater than 100 mg/L, the
potential for acute risk to freshwater is presumed to be low. If 100
mg/L was the toxicity endpoint, RQs would be \<0.01. There are no
guideline chronic toxicity data available with which to evaluate
potential chronic risk to freshwater fish. Chronic risk is presumed in
the absence of data.

#### Freshwater Invertebrates

No acute or chronic risk LOCs are exceeded freshwater invertebrates
(**Table 12**).

**Table 12.** Risk Quotients for freshwater invertebrates

+-------------+-------------+-------------+-------------+-------------+
| *           |             | **Peak      | **Toxicity  | **RQ**      |
| *Scenario** |             | EEC**       | Endpoint**  |             |
|             |             |             |             |             |
|             |             | **mg/L**    | **mg/L**    |             |
+-------------+-------------+-------------+-------------+-------------+
| FL Turf     | Acute       | 0.153       | 16.9        | \<0.01      |
+-------------+-------------+-------------+-------------+-------------+
| PA Turf     |             | 0.143       | 16.9        | \<0.01      |
+-------------+-------------+-------------+-------------+-------------+
|             |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| FL Turf     | Chronic     | 0.110       | 5           | 0.02        |
+-------------+-------------+-------------+-------------+-------------+
| PA Turf     |             | 0.093       | 5           | 0.02        |
+-------------+-------------+-------------+-------------+-------------+

#### Estuarine/Marine Fish

Chlormequat chloride is classified as practically nontoxic on an acute
exposure basis to estuarine/marine fish, *i.e.* the LC~50~ is greater
than 100 mg/L, and the potential for risk to estuarine fish is presumed
to be low. There are no chronic toxicity data available with which to
evaluate potential chronic risk to estuarine/marine fish.

#### Estuarine/Marine Invertebrates

No acute risk LOCs are exceeded for estuarine/marine invertebrates based
on the estuarine/marine invertebrate endpoint found in ECOTOX (**Table
13**). There are no chronic toxicity data available with which to
evaluate potential chronic risk to estuarine/marine invertebrates.

**Table 13.** Risk Quotients for estuarine/marine invertebrates.

+-------------+-------------+-------------+-------------+-------------+
| *           |             | **Peak      | **Toxicity  | **RQ**      |
| *Scenario** |             | EEC**       | Endpoint**  |             |
|             |             |             |             |             |
|             |             | **mg/L**    | **mg/L**    |             |
+-------------+-------------+-------------+-------------+-------------+
| FL Turf     | Acute       | 0.153       | 80          | \<0.01      |
+-------------+-------------+-------------+-------------+-------------+
| PA Turf     |             | 0.143       | 80          | \<0.01      |
+-------------+-------------+-------------+-------------+-------------+
|             |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| FL Turf     | Chronic     | 0.110       | \-          | \-          |
+-------------+-------------+-------------+-------------+-------------+
| PA Turf     |             | 0.093       | \-          | \-          |
+-------------+-------------+-------------+-------------+-------------+

#### Aquatic Plants

The acute risk LOC for non-listed vascular plant species is not exceeded
for aquatic plant species (**Table 14**). The acute risk LOC for listed
species is exceeded by more than a factor of three. RQs for aquatic
nonvascular plants are \<0.01.

**Table 14.** Risk Quotients for the most sensitive aquatic plants.

+-------------+-------------+-------------+-------------+-------------+
| *           |             | **Peak      | **Toxicity  | **RQ**      |
| *Scenario** |             | EEC**       | Endpoint**  |             |
|             |             |             |             |             |
|             |             | **mg/L**    | **mg/L**    |             |
+-------------+-------------+-------------+-------------+-------------+
| FL Turf     | Unlisted    | 0.153       | 2.8         | 0.05        |
+-------------+-------------+-------------+-------------+-------------+
| PA Turf     |             | 0.143       | 2.8         | 0.05        |
+-------------+-------------+-------------+-------------+-------------+
|             |             |             |             |             |
+-------------+-------------+-------------+-------------+-------------+
| FL Turf     | Listed      | 0.110       | 0.04        | 3.6^a^      |
+-------------+-------------+-------------+-------------+-------------+
| PA Turf     |             | 0.093       | 0.04        | 3.8^a^      |
+-------------+-------------+-------------+-------------+-------------+

exceeds acute risk LOC (RQ[\>]{.underline}1)

### Terrestrial

For terrestrial risk estimation, RQs are based on one growing cycle at
the maximum label rate applied three times at five day intervals. Three
growing cycles per year are allowed by the label; therefore exposure
could possibly be higher. While the target plants would be different for
each growing cycle, non-target species such as weeds could be subject to
multiple growing cycles.

#### Avian Acute

When both dose-based and dietary-based toxicity estimates are available
for birds, acute risk quotients are calculated using both a dose-based
and dietary-based approach. The dose-based RQs are calculated using a
body weight adjusted and consumption-weighted equivalent dose. The
adjustments account for the fact that smaller-sized animals have to
consume more food in terms of their body weight than larger animals and
that differential amounts of food have to be consumed depending on the
water content and nutritive value of the food. By expressing the Kenaga
nomogram estimated residues in terms of daily equivalent dose, estimated
environmental concentrations can then be compared to the dose-based
LD~50~. However, in the case of chlormequat chloride, RQs can only be
calculated from the LD~50~ since subacute dietary toxicity testing
failed to establish LC~50~ values. Although at the highest dose tested
in the Japanese quail dietary study chlormequat chloride would be
classified as slightly toxic on a subacute dietary exposure basis to
birds, *i.e.* the LC~50~ is \>3175 mg/L, it is not known how much
greater the LC~50~ would be, thus RQs based on dietary exposure are not
presented.

Chlormequat chloride is classified as slightly toxic on an acute oral
exposure basis. Dose-based RQs calculated using the acute oral LD~50~
are presented in **Table 15**. Dose-based RQs range from 6.9 for small
birds (20g) foraging on short grass to 0.06 large (1000g) birds foraging
on fruit/pods/large insects. The acute avian LOC (RQ≥0.5) is exceeded
for all size classes foraging on short grass, tall grass and broadleaf
plants/small insects. The acute risk to listed species LOC (RQ≥0.1) is
exceeded for small- and medium-size birds foraging on fruit/pods/large
insects.

**Table 15.** Upper-bound dose-based avian acute risk quotient (RQ)
values (LD~50~ = 556 mg/kg-bw).

  ---------------------------------------------- --------- ------------ --------- ---------- ---------- -----------
  **Forage items**                                         **Size                                       
                                                           class**                                      

                                                 **20g**                          **100g**              **1000g**

  Short grass                                              **6.9**^a^   **3.1**              **0.98**   

  Tall grass                                               **3.2**      **1.4**              **0.45**   

  Broadleaf/small insects                                  **3.9**      **1.7**              **0.55**   

  Fruits/pods/seeds/large insects                          *0.43*^b^    *0.19*               0.06       
  ---------------------------------------------- --------- ------------ --------- ---------- ---------- -----------

^a^Bold indicates exceeds acute risk to non-listed species LOC (RQ≥0.5)

^b^Italics indicates exceeds acute risk to endangered species LOC
(RQ≥0.1)

#### Avian Chronic

Because a NOAEC was below the lowest dose tested in the Japanese quail
avian reproduction study, definitive chronic RQs cannot be calculated
due to lack of data. However, calculating with the lowest dose tested
provides an indication of the minimum extent to which LOCs are exceeded.
RQ values calculated using the LOAEC from the Japanese quail study
(**Table 16**) exceed the chronic risk LOC (RQ≥1.0) for all forage
groups. The chronic LOC is exceeded by a factor of greater than 15X for
birds foraging on short grass. Since the actual NOAEC is likely to be
lower, avian chronic RQs will be higher than those presented here.

**Table 16. Chronic dietary-based RQs calculated from the Japanese quail
reproduction study. These RQs are lower than are indicated by the study
(LOAEC=158).**

  -------------------------------------------------------- --------------
  **Forage item**                                          **RQ**

  Short Grass                                              \>15\*

  Tall Grass                                               \>7\*

  Broadleaf plants/sm insects                              \>9\*

  Fruits/pods/seeds/lg insects                             \>1\*
  -------------------------------------------------------- --------------

\*Exceeds chronic risk LOC (RQ≥1.0)

#### Mammalian Acute

Mammalian acute RQs (**Table 17**) range from 0.01 for large (1000g)
granivorous mammals to 2.2 for small (15g) mammals foraging on short
grass, a 4-fold exceedance of the acute risk LOC (RQ≥0.5). There are
exceedances of the acute risk LOC for all size classes foraging on short
grass and broadleaf plant/small insects and for small- and medium-size
mammals foraging on tall grass. The listed species LOC is exceeded for
all-sized mammals foraging on all food categories except seeds and for
large mammals foraging of fruits/pods/lg insects

**Table 17.** Upper-bound dose-based mammalian acute risk quotient (RQ)
values for the use chlormequat chloride (LD~50~=487 mg/kg-bw).

  ---------------------------------------------- ------------ ---------- -----------
  **Forage items**                               **Size                  
                                                 class**                 

                                                 **15g**      **35g**    **1000g**

  Short grass                                    **2.2^a^**   **1.8**    **0.99**

  Tall grass                                     **0.99**     **0.84**   *0.45^b^*

  Broadleaf/small insects                        **1.2**      **1.0**    **0.56**

  Fruits/pods/large insects                      *0.13*       *0.12*     0.06

  Seeds                                          0.03         0.03       0.01
  ---------------------------------------------- ------------ ---------- -----------

^a^Bold indicates exceeds acute risk to non-listed species LOC (RQ≥0.5)

^b^Italics indicates exceeds acute risk to endangered species LOC
(RQ≥0.1)

#### Mammalian Chronic

When assessing potential chronic risk to mammals, in accordance with the
overview document, the dietary-based NOAEC is converted to a dose-based
NOAEL using the standard USFDA laboratory rat conversion, which can be
scaled to different mammalian size classes. The dose-based RQs are
calculated using a body weight adjusted and consumption-weighted
equivalent dose. The adjustments account for the fact that smaller-sized
animals have to consume more food in terms of their body weight than
larger animals and that differential amounts of food have to be consumed
depending on the water content and nutritive value of the food. By
expressing the Kenaga nomogram estimated residues in terms of daily
equivalent dose, estimated environmental concentrations can then be
compared to the dose-based NOAEC. Both sets of RQs are presented in
**Table 18**.

Dose-based RQs exceed the chronic risk LOC (1.0) for all size classes of
mammals foraging on short grass, tall grass and broadleaf plants/small
insects, by factors ranging from 3X to 12X . The only dietary-based RQ
value that exceeds the chronic risk LOC is for mammals foraging on short
grass; however, if dietary-based RQ values are adjusted to reflect that
different-sized animals consume differing amounts of food, the
dietary-based RQ values would likely be similar to the dose-based
values.

**Table 18.** Comparison of dose-based and dietary-based upper-bound
mammalian chronic risk quotient (RQ) values for the use chlormequat
chloride (NOAEC=86.4).

  ------------------------------------ --------- ---------------- --------- --------- ----------- --------- -------------------
  **Forage items**                               **Dose-based**                                             **Dietary-based**

                                       Size                                                                 
                                       class                                                                

                                       **15g**                              **35g**   **1000g**             

  Short grass                                    **12^a^**        **10**                          **5.6**   **1.4**

  Tall grass                                     **5.6**          **4.8**                         **2.6**   0.65

  Broadleaf/small insects                        **6.9**          **5.9**                         **3.1**   0.79

  Fruits/pods/large insects                      0.76             0.65                            0.35      0.09

  Seeds                                          0.17             0.14                            0.08      xx
  ------------------------------------ --------- ---------------- --------- --------- ----------- --------- -------------------

^a^Bold indicates exceeds chronic risk LOC (RQ≥1.0)

#### Non-target Plants

For a single application of chlormequat chloride (3.7 lbs ai/A) the
terrestrial plant LOC (1.0) is exceeded for dicotyledonous plants in
wetlands adjacent to chlormequat use sites. The RQ (**Table 19**) for
endangered monocotyledonous wetland plants for drift plus runoff
(loading) is 1.0 (at the highest dose tested); because there were no
effects on monocots at the highest dose tested, an EC~25~ was not
established, thus the RQ for non-listed plants is less than 1.0. For
dicots, the listed species LOC is exceeded with an RQ of 2.1 and the
non-listed LOC is exceeded with an RQ between 1.0 and 2.1. There are no
exceedances for adjacent upland species or as a result of drift alone.

**Table 19. Risk quotients for terrestrial plants. Monocots: seedling
emergence EC~25~\>1.9 lbs ai/A, NOEC=1.9 lbs ai/A; vegetative vigor
EC~25~\>3.4 lbs ai/A, NOEC=3.4 lbs ai/A. Dicots: seedling emergence
EC~25~\> 0.9 lbs ai/A, NOEC=0.9 lbs ai/A; vegetative vigor EC~25~=1.5
lbs ai/A, NOEC\<0.21 lbs ai/A.**

  -------------- --------------- ------------ -------- ------------ -------------- --------- -------
                 **Application   **Adjacent            **Adjacent                  **Drift   
                 Method**        Upland**              Wetland**                   Only**    

                                 Monocot      Dicot    Monocot      Dicot          Monocot   Dicot

  Nonlisted      Ground Spray    \<0.12       \<0.25   \<1.0        **\<2.1^a^**   \<0.02    0.04

  Listed         Ground Spray    0.12         0.25     **1.0^a^**   **2.1^a^**     0.02      0.04
  -------------- --------------- ------------ -------- ------------ -------------- --------- -------

^a^exceeds LOC for non-listed species

^b^EC~25~ was determined to be between 0.9 and 1.9 lbs ai/A.

^c^meets or exceeds the LOC for listed species

## Risk Description

Based on this screening-level deterministic risk assessment, EFED cannot
refute the risk hypothesis that the labeled outdoor uses of chlormequat
chloride may pose risk of adverse effects to non-target species.
Chlormequat chloride is expected to be moderately mobile to mobile (FAO
classification scheme) in the environment. Major routes of dissipation
in the environment include microbial degradation in soils and aquatic
systems. There is uncertainty regarding chlormequat chloride's
persistence in the environment. In aerobic soil metabolism studies,
chlormequat chloride degraded with half-lives ranging from 4-6 weeks.
But there were significant unidentified residues in these studies. In
aquatic environments, chlormequat chloride was short-lived, degrading
with half-lives of \~ 1 week. However, significant nonextractable
residues were detected in these studies and it is uncertain whether or
not they consist of parent chlormequat chloride and/or residues of risk
concern.

Although potential risk to aquatic animals appears to be low, available
data indicate that the outdoor use of chlormequat chloride has the
potential to adversely affect listed aquatic plants and non-target
terrestrial animal and plant species. Due to important data gaps
regarding Agency guideline studies, there is appreciable uncertainty
regarding some risk conclusions. While this assessment uses conservative
assumptions, greater refinement and additional data would be required to
preclude potential risk given the exceedances noted in the previous
section of the document. For terrestrial species, there is potential
acute risk to birds for most size class/forage item categories, as well
as the terrestrial-phase amphibians and reptiles for which birds are
considered surrogates. The chronic risk LOC for birds is exceeded across
all forage items; however, RQs for chronic effects will be higher
because a NOAEC has not been determined. Potential acute risk is also
indicated to mammals in most of the size class/forage categories, and
potential chronic risk to mammals is indicated for all-size classes in
three of the five forage categories. Consistent with chlormequat being a
PGR, potential risk to non-target aquatic vascular plants and to
terrestrial plants in wetlands adjacent to use sites is indicated.

### Aquatic

No aquatic animal RQ exceeded any LOC; however, chronic data are lacking
for freshwater fish and potential risk cannot be precluded in the
absence of data. However, based on the use of acute-to-chronic ratios
for freshwater invertebrates (acute and chronic) and freshwater fish
(acute), and using the lowest available LC~50~ (\>100 mg/L), the chronic
RQ would be \<0.5, less than half the chronic LOC. The acute to chronic
ratio for fish would have to be more than double that for the daphnids
tested before the LOC would be exceeded. Additionally, based on the
aerobic aquatic metabolism half-lives, chlormequat chloride is not
expected to persist in most waterbodies.

Based on submitted data, aquatic vascular plant species are potentially
affected by chlormequat chloride. Although the unlisted species LOC is
not exceeded, the listed species LOC is exceeded by a factor of more
than three for aquatic vascular plants. Non-vascular plants are
considerably (several orders of magnitude) less sensitive to chlormequat
chloride than vascular plants.

Consistent with a screening-level approach, the aquatic exposure
estimates used in this assessment are designed to be conservative. Major
assumptions that contribute to the protective nature of the aquatic
exposure estimates include the applicability of the standard models and
surrogate PRZM scenarios to the nursery/shade house use, the application
intervals modeled, and the area treated. The PRZM/EXAMS models and
scenarios used in this assessment were developed to simulate pesticide
applications in open agricultural fields and not specifically for
containerized ornamentals and bedding plants in nurseries/shade houses.
The impact of rainfall and corresponding pesticide transport is likely
dampened due to the use of containers and/or shade covers relative to
open agricultural fields, which leads to a protective assessment. The
application interval was assumed to be 5 days (which is the minimum
permitted by the label) for all 9 applications. Since there is a maximum
of 3 applications per crop cycle, it is likely that the interval between
applications of subsequent crop cycles will be greater than 5 days, and
thus the 5-day interval is likely a protective assumption. This will
likely result in an overestimation of chronic exposure since a longer
interval between applications would allow for greater degradation in the
water body prior to subsequent applications. Also, the standard
ecological aquatic modeling scenario consists of application to an
entire 10-ha field simultaneously. The Cycocel^®^ label, however, states
that applications by mechanical (tractor) multi-nozzle sprayers may not
exceed one acre of plants per day, per mixer/loader/applicator. The
assumption that the entire 10-ha field of bedding plants is treated
simultaneously with chlormequat chloride is likely a protective
assumption. []{.mark}

### Terrestrial

Dietary-based and dose-based avian RQ values are calculated using the
sub-acute dietary LC~50~ and the acute oral LD~50~. The dose-based
calculation takes into account that different-sized animals have to
consume different amounts of food and the differing nutritional value of
feed items. The LD~50~ may give a better indication of inherent toxicity
than the LC~50~ in cases where food avoidance may be an issue in the
test animals. The greater energy demands in wild birds could make
similar avoidance in natural settings unlikely. Because a subacute
dietary LC~50~ for chlormequat chloride was not defined, and the LC~50~
exceeded the highest dietary test concentration (3175 ppm), no
definitive dietary-based RQs were calculated. If the highest dose tested
were used to calculate RQs, the acute risk LOC would be exceeded for
short grass and the restricted use and listed species LOCs would be
exceeded for the tall grass and broadleaf plants/small insects forage
categories. Due to the mass of chemical applied, even at the high-end
regulatory limit for testing, 5000 ppm, above which chemicals are
classified as practically nontoxic, the listed species LOC would be
exceeded in three of the four forage categories. Because of the
magnitude of the EECs, *i.e.* greater than 1/10th the highest dose
tested, risk to endangered species on a dietary basis cannot be
precluded.

Dose-based RQs result in exceedances of the acute risk LOC for all size
classes of birds foraging on short grass, tall grass and broadleaf
plants/small insects and small (20g) birds foraging on
fruit/pods/seeds/large insects. The acute risk LOC for restricted use
and listed species is also exceeded for medium-sized birds foraging on
fruit/pods/seeds/large insects. RQs are calculated using upper-bound
Kenaga values. If mean Kenaga values (expected to be exceeded about 50%
of the time) were used to calculate the RQs, acute risk LOC would still
be exceeded for small- and medium-sized birds foraging on short grass,
tall grass and broadleaf plants/large insects and large birds foraging
on short grass. The listed species LOC would be exceeded for large birds
foraging on tall grass and broadleaf plants/large insects and for small-
and medium-sized birds foraging on fruits/pods/seeds/large insects.

Because a NOAEC was not determined in the avian reproduction study,
definitive chronic RQ values could not be calculated. However, the
lowest dose tested was used to give an indication of potential chronic
risk. The chronic risk LOC is exceeded for birds across all forage items
at the maximum application rate for one growing cycle. The chronic RQ
exceeded the LOC by \>15-fold for birds foraging on short grass. The
most sensitive endpoints were reduced feed consumption and decreased
male body weight gain. While there is generally a high-degree of
variability in feed consumption, the reduced feed consumption in the
non-guideline study may imply the birds were not acclimated properly.
Males in all three treatment groups lost weight relative to their
starting weight, up to an average of 4.5g in the highest treatment
level. The control males gained an average of 2.1g. But the ecological
significance of this endpoint is not clear. A loss of 4.5g represents a
6% reduction in weight, based on an average size Japanese quail. For
male birds that provide parental care of the young, given the increased
energy demands on the wild birds (relative to study conditions), this
reduced weight may lead to reduced survivorship or impaired development
of offspring. Additionally, if a wild species was more sensitive than
the Japanese quail, the effect could be amplified.

There were effects seen at the highest dose tested that have could be
indicative of effects on endocrine-mediated processes (*e.g.*, eggshell
thinning). Hypothetically ignoring effects at the lowest dose, using the
NOAEC for these other effects (387 mg ai/kg bw), the chronic RQs would
exceed the LOC in three of the four forage categories by 3- to 6-fold.

Chronic values (calculated with the lowest dose tested) are based on
upper-bound Kenaga values. The non-definitive RQs based on mean Kenaga
values also exceed the chronic risk LOC for birds across the same forage
categories. EECs exceed the lowest dose tested for more than 100 days
for all three forage categories, based on the upper-bound residues, and
for more than 50 days based on the mean residues, indicating that
residues above the chronic toxicity threshold could be available to
foraging wildlife for an extended period. The chronic risk LOC based on
mean residues is expected to be exceeded approximately half of the time.

Terrestrial animal RQs are calculated using a default foliar half life
of 35 days. If data were generated that demonstrated, hypothetically,
three-day half life was appropriate, the maximum RQ would be reduced by
roughly 50%. A reduction in the application rate would also reduce RQs.
However, because a NOAEC is not established, it is not known how far
these parameters would have to be changed to get all RQs below the LOC.
Even with a less conservative foliar dissipation rate of 3 days rather
than the default 35-day half-life, chronic RQs would still exceed the
LOC by a factor of 8x.

Because the Japanese quail reproduction study did not establish a NOAEC,
the utility of the study was greatly reduced for this risk assessment.
Additionally, the study deviates appreciably from EPA guidelines. The
Agency typically prefers birds have a 10-week pre-laying exposure period
followed by a 10-week exposure period during egg laying. The
supplemental reproduction study submitted to the Agency was designed as
an eight-week laying study, with a two-week pre-treatment period,
followed by a six week treatment period. It is not clear how the results
of this study would relate to an Agency guideline study.

Avian exposure modeling considered only one growing cycle. Since three
growing cycles are allowed per year, the mass of chlormequat chloride
available may be underestimated. However, since target plants are
different for each application cycle, only non-target forage items
(*e.g.* weeds) would potentially be subjected to applications over more
than one growing cycle.

The acute risk LOC is exceeded for all size classes of mammals foraging
on short grass and broadleaf plant/small insects, as well as small and
medium size classes foraging on short grass and broadleaf plants/small
insects. The acute risk to listed species LOC (RQ≥0.1) is exceeded for
small and intermediate size classes foraging on fruits/pods/large
insects and large mammals foraging on tall grass. RQs are calculated
using upper bound (95%) Kenaga values. RQs calculated with mean Kenaga
values still exceed the acute risk LOC for small and medium size classes
foraging on short grass and the listed species LOC for all size classes
foraging on short grass and small and medium size classes foraging on
tall grass and fruit/pods/large insects; however, mean exposure values
are expected to be higher about half of the time.

If the rate per application (for three applications, five days apart)
was below 0.25 lbs ai/A only small and medium-sized mammals would exceed
the listed species LOC at the upper-bound residues. Using a minimum
application interval of 21-day or using a hypothetical three day half
life results in lower RQs, but does not appreciably change the risk
picture. However, the calculated RQs are for only one growing cycle, and
therefore do not represent the total mass of chlormequat chloride
potentially available for exposure. Since target plants are different
for each application cycle, only non-target forage items (*e.g.* weeds)
would potentially be subjected to applications over more than one
growing cycle.

Two methods (dietary-based and dose-based) are used to estimate chronic
risk to mammals and can result in considerably different RQ estimates.
The dose-based (LD~50~) calculation takes into account that
different-sized animals have to consume different amounts of food and
that the food itself has differing nutritional value. The acute oral
LD~50~ is believed to provide a better indication of inherent toxicity
than the LC~50~ in cases where food avoidance may be an issue in the
test animals. If the dietary-based RQ values are adjusted to account for
these factors, it is possible that these RQs would be roughly similar to
the dose-based RQ values. Dose-based chronic RQs using the upper-bound
residues exceed the chronic risk LOC for all size classes foraging on
short grass, tall grass and broadleaf plant/small insect by factors of
up to 12-fold. Dietary-based chronic risk quotients exceed the LOC using
upper-bound residue estimates for mammals foraging on short grass and
broadleaf plants/small insects. Using the mean residues, dose-based RQs
(1.0-4.3) exceed the LOC for all size classes foraging on short grass,
tall grass and broadleaf plants/small insects, except large mammals on
tall grass (RQ=0.8). Dietary-based RQs do not exceed the LOC based on
mean residues; however, the mean residues are expected to be exceeded
about half of the time. []{.mark}

Given that chlormequat chloride is used as a PGR, effects on plants are
to be expected. A single application of chlormequat chloride results in
an exceedance of the acute risk to unlisted species LOC for dicots and
exceedance of the listed species LOC for both monocots and dicots in
wetlands adjacent to use sites. It is not clear to what degree wetlands
would be adjacent to the use sites, but it cannot be ruled out based on
this screening level assessment. It is also not known what effect
cumulative applications of chlormequat chloride might have on sensitive
plants. Because one of the effects seen in the study was a reduction in
number of seeds emerged, affected wetlands could be subject to reduced
numbers of sensitive individuals through seed mortality, or a delay the
emergence of sensitive plants. Delayed emergence may adversely affect a
plant's ability to reproduce or affect the availability of a plant as
food source for higher trophic levels at a sensitive time.

Additionally, the vegetative vigor study did not establish a NOAEC,
based on \>25% effects at the lowest dose tested. However, based on the
drift RQ, the NOAEC would need to be approximately 5X lower than the
lowest rate tested to result in an exceedance for drift alone. The
available data, and the product label, suggest there are differences
among species in sensitivity to chlormequat chloride, and only six
species were tested for each study, rather than the 10 per study
preferred. Because the non-listed plant LOC is exceeded for dicots,
potential indirect effects on listed animals cannot be precluded based
on this screening-level risk assessment.

Number range CHAPTER ***Endocrine Disruption Potential***

In a non-guideline avian reproduction study, chronic exposure to
chlormequat chloride resulted in increased numbers of cracked eggs in
birds and a significant decrease in testes weight, increased eggshell
thinning and reduced eggshell strength at the highest dose tested.
Additionally, delayed development is reported in mammalian chronic
studies. While these effects are often associated with effects on
endocrine-mediated pathways, it is unclear from the submitted study
whether chlormequat chloride has the capacity to act on
endocrine-mediated processes.

The EPA is required under the FFDCA, as amended by FQPA, to develop a
screening program to determine whether certain substances (including all
pesticide active and other ingredients) "*may have an effect in humans
that is similar to an effect produced by a naturally occurring estrogen,
or other such endocrine effects as the Administrator may designate*."
Following the recommendations of its Endocrine Disruptor Screening and
Testing Advisory Committee (EDSTAC), EPA determined that there was
scientific basis for including, as part of the program, the androgen and
thyroid hormone systems, in addition to the estrogen hormone system. EPA
also adopted EDSTAC's recommendation that the Program include
evaluations of potential effects in wildlife. For pesticide chemicals,
EPA will use FIFRA and, to the extent that effects in wildlife may help
determine whether a substance may have an effect in humans, FFDCA
authority to require the wildlife evaluations. As the science develops
and resources allow, screening of additional hormone systems may be
added to the Endocrine Disruptor Screening Program (EDSP). When the
appropriate screening and/or testing protocols being considered under
the Agency's EDSP have been developed, chlormequat chloride may be
subjected to additional screening and/or testing to better characterize
effects related to endocrine disruption.

## Uncertainties and Data Gaps

The environmental fate dataset for chlormequat chloride is incomplete.
There are no acceptable data for hydrolysis, photolysis, anaerobic soil
metabolism and terrestrial field dissipation. It was assumed that
chlormequat chloride is stable with respect to these degradation
pathways. In the aerobic soil and aerobic aquatic metabolism studies all
transformation products greater than 10% of the applied may not have
been identified. A total residue approach, which assumed that all
unidentified extractable residues are of similar toxicity to parent
chlormequat chloride, was used for modeling.

The extent to which the species tested, which are generally chosen for
traits that make them suitable for use in laboratory testing, represent
the sensitivity spectrum of non-target organisms is not clearly
understood. It is possible that the laboratory tests represent a
relatively insensitive portion of the non-target organisms that could be
potentially exposed. If that were the case, the potential risk to
animals would be underestimated.

The environmental effects database contains areas of uncertainty. In the
avian reproduction studies with the Japanese quail, deviations from
Agency guidelines range from fairly minor, such as the use of a test
species other than those preferred by the Agency, to an appreciable
difference in study design. Agency guideline avian reproduction studies,
conducted with the mallard duck and/or northern bobwhite quail, are
conducted for 20-22 weeks, with a 10-week pre-laying exposure followed
by a 10-week egg laying exposure period. The submitted study was
conducted with a two week pre-treatment period followed by a 6-week
exposure period, all with laying birds. It is uncertain how the results
of this study would relate to a guideline study. The submitted study did
not establish a NOAEC, an important assessment endpoint, as
statistically significant effects (feed consumption, adult male weight
gain) were seen at the lowest dose tested.

Additionally, there are no data regarding chronic effects to fish and a
NOEC was not defined in the vegetative vigor study. Given the propensity
of chlormequat to persist under some environmental conditions, there is
a potential for chronic exposure. The lack of chronic toxicity data is a
major impediment to estimating potential risk.

The T-REX model uses conservative screening-level assumptions, such as
the use of Hoerger-Kenaga upper-bound residues and that 100% of the
animals' diet consists of contaminated food. In this case, chlormequat
chloride will be used in nurseries and shadehouses and applied primarily
to relatively high-value plants. It seems logical that operators will
employ various methods to limit browse on the target plants. However,
weeds, seeds and insects could be contaminated via direct deposition and
spray drift and make up an appreciable portion of an animal's diet. It
is not possible in this screening-level assessment to determine the
likelihood of sufficient exposure to pose risk.

It is unlikely that the base assumption in TerrPlant for channelized
runoff to wetlands will be met in the case of chlormequat chloride. The
model assumes 10 acres draining to one acre, but the label limits
application to one acre per day. Although it is possible for 10
contiguous acres to be treated, or even for the same acre to be treated
10 times over 10 days, this temporal element is not accounted for by
TerrPlant. Further, application of chlormequat chloride is limited to
containerized ornamentals and bedding plants, providing for at least a
minimal disconnect from the greater watershed. This represents a source
of uncertainty in the assessment.

# Conclusion

This screening-level risk assessment for the proposed outdoor use of
chlormequat chloride indicates potential risk to aquatic and terrestrial
plants, birds, and mammals. It is not clear what potential effects may
occur in reptiles or terrestrial-phase amphibians, although there are
indications of risk to their surrogate taxon, birds. Based on potential
risk to sensitive plant species, there is a potential for indirect
effects to most terrestrial animals given chlormequat chloride's
potential effect on primary productivity and wetland habitat. Indirect
effects to species with obligate relationships to aquatic vascular
plants cannot be ruled out based on this assessment. []{.mark}

#  Threatened and Endangered Species 

Levels of concern for threatened and endangered species are exceeded for
several types of wildlife, including birds, mammals and both aquatic and
terrestrial plants. Because potential risk is indicated in their
surrogates, there is potential risk to listed amphibians and reptiles.
Exceedance of LOCs for plants indicate concern for indirect effects on
listed terrestrial animal species reliant on susceptible plant
communities, or those solely dependent on a sensitive plant for some
portion of their life cycle (obligate relationships). Due to lack of
data, chronic risk to freshwater fish is presumed.

The Overview of Ecological Risk Assessment Process in the Office of
Pesticide Programs, U.S. Environmental Protection Agency (USEPA 2004,
the 'Overview Document') discusses methods for providing the U.S. Fish
and Wildlife Service (USFWS) and the National Marine Fisheries Service
(NMFS), collectively 'the Services', with additional information
regarding the listed animal species acute levels of concern (LOCs). A
tool has been developed by EFED in consultation with the Services to
evaluate the chance of an individual organism being affected given the
toxicity of the chemical to the organism and the dose-response curve
(see **Appendix IV** for more detail). For the present time, the Excel
spreadsheet tool IECV1.1 will allow for such calculations by entering in
the mean slope estimate and the 95 percent confidence bounds of that
estimate as the slope parameter for the spreadsheet. It is important to
note that the model output can go as low as 10^-16^ in estimating the
event probability. This cut-off is a limit in the Excel spreadsheet
environment and should not be interpreted as an agreed upon lower bound
threshold for concern for individual effects in any given listed
species. The toxicity studies used in this risk assessment do not report
dose-response curves, and due to resource limitations, it was not
possible to determine if the data are available to calculate the curves.
In cases where dose-response curves are unavailable, event probabilities
are calculated for the listed species LOC based on a default slope
assumption of 4.5 as per original Agency assumptions of typical
dose-response slope cited in Urban and Cook (1986).

For birds and mammals, the listed species LOC is 0.1. The chance of one
individual being affected at an RQ equal to the LOC is 1 in 294,000. For
birds, the highest acute RQ in this assessment is 6.9, for small-sized
birds foraging on short grass. If listed birds are as sensitive to
chlormequat chloride as the endpoint used in the model indicates, and
exposed to the concentration modeled, the chance of an individual being
affected is approximately 1 in 1. Large-sized birds foraging on
fruits/pods/large insects (RQ = 0.55) results in the potential for 1 in
8 individuals to be affected. The highest acute mammalian RQ in this
assessment is 2.2, for small-sized mammals foraging on short grass. If
listed mammals are as sensitive to chlormequat as the endpoint used in
the model indicates, and exposed to the concentration modeled, the
chance of an individual being affected is approximately 1 in 1. For
medium-sized mammals foraging on fruits/pods/large insects (RQ = 0.12;
lowest mammal RQ exceeding the LOC), the chance of an individual effect
is about 1 in 58,000.

Because the screening-level risk assessment indicates that the outdoor
chlormequat chloride uses exceed the endangered species LOC for birds
(terrestrial-phase amphibians, reptiles), mammals, and plants, a 'may
affect' designation can not be precluded based on this assessment. Due
to lack of data, chronic risk to freshwater fish is presumed.
Additionally, the acute risk LOC for terrestrial plants is exceeded. The
Agency considers this to be indicative of a potential for adverse
effects to those listed species that rely either on a specific plant
species (plant species obligate) or multiple plant species (plant
dependant) for some important aspect of their life cycle (indirect
effects). Indirect effects may include general habitat modification,
host plant loss, and food supply disruption. Further analysis regarding
the overlap of individual species with each use site is required prior
to determining the likelihood of potential impact to listed species.
Such a refinement is outlined in the following sections.

## Action Area

For listed species assessment purposes, the action area is considered to
be the area affected directly or indirectly by the Federal action and
not merely the immediate area involved in the action. At the initial
screening-level, the risk assessment considers broadly described
taxonomic groups and so conservatively assumes that listed species
within those broad groups are co-located with the pesticide treatment
area. This means that terrestrial plants and wildlife are assumed to be
located on or adjacent to the treated site and aquatic organisms are
assumed to be located in a surface water body adjacent to the treated
site. The assessment also assumes that the listed species are located
within an assumed area, which has the relatively highest potential
exposure to the pesticide, and that exposures are likely to decrease
with distance from the treatment area.

If the assumptions associated with the screening-level action area
result in RQs that are below the listed species LOCs, a \"no effect\"
determination conclusion is made with respect to listed species in that
taxa, and no further refinement of the action area is necessary.
Furthermore, RQs below the listed species LOCs for a given taxonomic
group indicate no concern for indirect effects upon listed species that
depend upon the taxonomic group covered by the RQ as a resource.
However, in situations where the screening assumptions lead to RQs in
excess of the listed species LOCs for a given taxonomic group, a \"may
affect\" designation cannot be precluded and may be associated with
direct effects on listed species belonging to that taxonomic group or
may extend to indirect effects upon listed species that depend upon that
taxonomic group as a resource. In such cases, additional information on
the biology of listed species, the locations of these species, and the
locations of use sites need to be considered along with available
information on the fate and transport properties of the pesticide to
determine the extent to which screening assumptions regarding an action
area apply to a particular listed organism. These subsequent refinement
steps could delineate how this information would impact the action area
for a particular listed organism and may potentially include areas of
exposure that are downwind and downstream of the pesticide use site.

## Taxonomic Groups Potentially at Risk 

The RQs calculated based on the ratio of EECs to toxicity endpoints, in
this case the LD~50~ and NOAEC from animal toxicity studies and NOEC
from plant toxicity studies, indicate potential risk to listed birds
(terrestrial-phase amphibians, reptiles), mammals, and plants (aquatic
vascular and terrestrial; **Table 20**). Due to lack of data, chronic
risk to fish is presumed. **Appendix VI** provides a tabulation of
species for each taxon that may be affected by this action.

Should estimated exposure levels occur in proximity to listed resources,
the available screening-level information suggests a potential concern
for direct effects on some listed species associated with the proposed
new uses of chlormequat chloride. This Level I screening assessment is
based on the initial assumption that listed species within the taxonomic
groups of concern are actually present in areas for which the estimated
exposure levels used for RQ calculation can be expected to occur. A
specific determination of "may affect" for any RQ in excess of listed
species LOCs cannot be made until a determination of the co-occurrence
of the listed species with the action area has been determined. This was
not done for this assessment.

**Table 20**. Listed species risks associated with potential direct or
indirect effects due to the proposed applications of chlormequat
chloride in containerized ornamental production.

+------------------+-----------------+---------------+----------------+
| **Listed Taxon** | **Direct        | **Direct      | **Indirect     |
|                  | Effects**       | Effects**     | Effects**      |
|                  |                 |               |                |
|                  | **Acute**       | **Chronic**   |                |
+------------------+-----------------+---------------+----------------+
| Terrestrial and  | Yes             | \-            | Yes^1^         |
| semi-aquatic     |                 |               |                |
| plants -         |                 |               |                |
| monocots         |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Terrestrial and  | Yes             | \-            | Yes^1^         |
| semi-aquatic     |                 |               |                |
| plants - dicots  |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Insects          | No              | \-            | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Birds            | Yes             | Yes           | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Terrestrial      | Yes             | Yes           | Yes^1^         |
| phase amphibians |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Reptiles         | Yes             | Yes           | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Mammals          | Yes             | Yes           | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Aquatic plants   | Yes             | \-            | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Freshwater fish  | No              | No data^2^    | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Aquatic phase    | No              | No data       | Yes^1^         |
| amphibians       |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Freshwater       | No              | No            | Yes^1^         |
| invertebrates    |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Mollusks         | No data         | No data       | Yes^1^         |
+------------------+-----------------+---------------+----------------+
| Marine/estuarine | No              | No data       | Yes^1^         |
| fish             |                 |               |                |
+------------------+-----------------+---------------+----------------+
| Marine/estuarine | No              | No data       | Yes^1^         |
| crustaceans      |                 |               |                |
+------------------+-----------------+---------------+----------------+

^1^Nonlisted LOC exceeded for terrestrial and semi-aquatic plants
(monocots and dicots), therefore potential for adverse effects to those
species that rely either on a specific plant species or multiple plant
species. Plant indirect effects may include general habitat
modification, host plant loss, and food supply disruption.

^2^Lack of data does not preclude potential risk.

## Indirect Effects Analysis 

Because terrestrial plant RQs are above non-endangered species LOCs, the
Agency considers this to be indicative of a potential for adverse
effects to those listed species that are plant species obligates or
plant dependant for some important aspect of their life cycle. The
extent to which the new uses of chlormequat chloride will indirectly
affect listed animal species will require identification of listed
species that co-occur in areas of chlormequat chloride use and an
evaluation of critical habit as described below. Because of the
potential extent of the proposed uses of chlormequat chloride, EFED
cannot preclude the possibility of a 'may affect' designation for listed
species based on this assessment.

## Critical Habitat

The screening-level risk assessment has identified potential concerns
for direct and indirect effects on listed species associated with action
areas where chlormequat chloride is used. In light of the potential for
effects on listed species, the next step for EPA and the Services is to
identify which listed species and critical habitat are potentially
implicated. Analytically, the identification of such species and
critical habitat can occur in either of two ways. First, the agencies
could determine whether the action area overlaps critical habitat or the
occupied range of any listed species. If so, EPA would examine the
potential impact of the use of chlormequat chloride on listed species
and whether impacts on non-endangered species would affect the listed
species indirectly or directly affect a constituent element of the
critical habitat. Alternatively, the agencies could determine which
listed species depend on biological resources, or have constituent
elements that fall into, the taxa that may be directly or indirectly
impacted by the pesticide. Then EPA would determine whether use of the
pesticide overlaps the critical habitat or the occupied range of those
listed species. At present, the information reviewed by EPA does not
permit use of either analytical approach to make a definitive
identification of species that are potentially impacted indirectly or
critical habitats that are potentially impacted directly by the use of
the pesticide. EPA and the Services will work together to conduct the
necessary analysis.

This screening-level risk assessment provides a table of potential
biological entities that, if they are constituent elements of one or
more critical habitats, would be of potential concern (**Appendix VI**).
These correspond to the taxa identified above as being of potential
concern for indirect effects and include freshwater fish (aquatic-phase
amphibians) (presumption of chronic risk), birds (terrestrial-phase
amphibians, reptiles), and mammals, as well as terrestrial and aquatic
plants. These tables should serve as an initial step in problem
formulation for further assessment of critical habitat impacts outlined
above.

## Co-occurrence Analysis

The goal of the analysis for co-location is to determine whether sites
of pesticide use are geographically associated with known locations of
listed species. At the screening level, this analysis is accomplished
using the Agency's LOCATES (v. 2.10.3) database. The database uses
location information for listed species at the county level and compares
it to agricultural census data for crop production at the same county
level of resolution. The database contains Federally-listed species that
are located within states known to produce the crop upon which the
pesticide will be used. Because the Level-I screening assessment
considers **both** direct and indirect effects across generic taxonomic
groupings, it is not possible to exclude any taxonomic group from a
LOCATES database query for a screening-level risk assessment. The
utility of the database is limited in the case of chlormequat chloride
by the lack of resolution in the data regarding containerized nurseries
and bedding plant production sites.

Because the outdoor uses of chlormequat chloride are new, the extent of
its potential use has not yet been determined. As noted previously, at
the screening level, it is not possible to evaluate all the potential
direct and indirect effects that could impact endangered animals.
Therefore, a 'may effect' designation cannot be precluded for listed
animals based on this assessment.

# References

[]{.mark}

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature
review and evaluation of the EPA food-chain (Kenaga) nomogram, an
instrument for estimating pesticide residues on plants. *Environ.
Toxicol. Chem.* 13: 1383-1391.

Hoerger, F. and E.E. Kenaga. 1972. Pesticide residues on plants:
correlation of representative data as a basis for estimation of their
magnitude in the environment. *Environmental Quality and Safety.* 1:
9-28.

Latimer, J.G., H.L. Scoggins and T.J. Banko. 2001. Using Plant Growth
Regulators on Containerized Herbaceous Perennials. Virginia Cooperative
Extension Service. Publication 430-103. 16pp.

Linden, E., B.E. Bengtsson, O. Svanberg, and G. Sundstrom. 1979. The
Acute Toxicity of 78 Chemicals and Pesticide Formulations Against Two
Brackish Water Organisms, the Bleak (*Alburnus alburnus*) and the
Harpacticoid *Nitocra spinipes*. *Chemosphere* 8(11/12):843-851

NASS. 2006. 2002 Census of Agriculture. U.S. Department of Agriculture,
National Agricultural Statistics Service. Online at:
http://www.nass.usda.gov/Census_of_Agriculture/index.asp. Accessed on
August 27, 2006.

Urban D.J. and N.J. Cook. 1986. Hazard Evaluation Division Standard
Evaluation Procedure Ecological Risk Assessment. EPA 540/9-85-001. U.S.
Environmental Protection Agency, Office of Pesticide Programs,
Washington, DC.

USEPA. 2002. Guidance for Selecting Input Parameters in Modeling the
Environmental Fate and Transport of Pesticides. U.S. Environmental
Protection Agency, Office of Prevention, Pesticides and Toxic
Substances, Office of Pesticide Programs, Environmental Fate and Effects
Division. Feb. 28, 2002. Online at:
http://www.epa.gov/oppefed1/models/water/input_guidance2_28_02.htm/.

USEPA. 2004. Overview of Ecological Risk Assessment Process in the
Office of Pesticide Programs, U.S. Environmental Protection Agency.
Office of Prevention, Pesticides and Toxic Substances, Office of
Pesticide Programs, Washington, DC.

USEPA. 2006. Water Models. U.S. Environmental Protection Agency,
Pesticides: Science and Policy. Last updated May 2, 2006. Online at:
http://www.epa.gov/oppefed1/models/water/.

Willis, Guye H., and Leslie.L. McDowell. 1987. Pesticide Persistence on
Foliage. in *Reviews of Environmental Contamination and Toxicology*.
100:23-73.

Yeager T., C. Gilliam, T. Bilderback, D. Fare, A. Niemiera, K. Tilt.
2000. Best Management Practices: Guide for Producing Container-Grown
Plants. Southern Nursery Association. 69 pp.

# Appendix I. Environmental Fate and Transport Data

**Abiotic Degradation**

*Hydrolysis*

There are no acceptable data to fulfill this guideline requirement.

*Aqueous Photolysis*

There are no acceptable data to fulfill this guideline requirement.

*Soil Photolysis*

There are no acceptable data to fulfill this guideline requirement.

**Metabolism**

*Aerobic Soil Metabolism*

In an aerobic soil metabolism study classified as **supplemental** (MRID
46751225), chlormequat chloride decreased from 91-103% at day 0 to
47-60% at day 28, 22-37% at day 56, and was 11-17% at day 112 in two
loamy sand soils and two silt loam soils. Soils were was sequentially
extracted four times with methanol:water (1:1, v:v), then four times
with acidified water (pH 2). Nonextractable residues increased from
0.9-6.0% at day 0 to 19.0-27.8% at 112 days. Chlormequat chloride
degraded with log-linear half-lives of 34-43 d. There were no identified
major degradates; however up to 10.7% and 43.7% of the applied
radioactivity in the soil extracts of two soils was unaccounted for and
no attempt was made to identify the transformation product(s).
Consequently, all transformation products detected at \>10% of the
applied may not have been identified. Using a total residue approach
that assumes all uncharacterized extractable residues are of equal
toxicity to chlormequat chloride results in half-lives of 32 -- 132 d.

*Anaerobic Soil Metabolism*

There are no acceptable data to fulfill this guideline requirement.

*Aerobic Aquatic Metabolism*

In an aerobic aquatic metabolism study classified as **supplemental**
(MRID 46715227), chlormequat chloride decreased in the total systems
from 105-108% at day 0 to 37-92% at day 7, 1.4-20% at day 14, 1.7-6.3%
at day 30 and was 0.1-0.6% at study termination in a river water-sandy
loam and pond water-silt loam system. Sediment were sequentially
extracted 1-3 times with methanol:acidified (pH 2) water (1:1, v:v),
followed by 1-5 times with acidic (pH 2) water. There were no identified
major degradates; however there was an unidentified TLC fraction at a
maximum of 11.1 and 13.4% of the applied radioactivity in the sediment
and total system of the river water-sandy loam system. Nonextractable
residues increased from 1.0-2.6% at time 0 to 49.0-59.2% at 30 days and
were 27.7-31.3% at 105 study termination. Chlormequat chloride degraded
with total system half-lives of 4.9-8.7d.

*Anaerobic Aquatic Metabolism*

Not required

**Mobility**

*Batch Equilibrium*

In a batch equilibrium study classified as **acceptable** (MRID
46715228), following 16 hours of equilibration, 11.6-65.3%, 38.9-78.0%,
13.8-40.2%, and 16.2-72.7% of the applied \[^14^C\]chlormequat chloride
was adsorbed to a Speyer 2.2 loamy sand, Sisseln sandy loam, Les
Evouettes silt loam, and Wilson sand soils, respectively. Following the
second desorption step, the percent of \[^14^C\]chlormequat chloride
desorbed from the test soils, as percent of the radioactivity adsorbed,
was 11.7-47.2% for the Speyer 2.2 loamy sand, 14.7-58.2% for the Sisseln
I sandy loam, 22.0-63.6% for the Les Evouettes silt loam, and 13.4-43.6%
for the Wilson sand soils. Freundlich adsorption and desorption
coefficients are listed in the table below.

  ------------ ------------------- -------- ------------ -------- ------------ -------- ------------ ---------------
  Soil         Number range                                       Desorption                         
               CHAPTERAdsorption                                                                     

               K~F~                1/n      rNumber      K~Foc~   K~F~         1/n      rNumber      Number range
                                            range                                       range        CHAPTERK~Foc~
                                            CHAPTER^2^                                  CHAPTER^2^   

  Speyer 2.2   1.25                0.5109   0.9899       54.6     1.93         0.4695   0.9841       84.3
  Loamy sand                                                                                         

  Sisseln I    4.57                0.6905   0.9984       291      5.29         0.6187   0.9982       337
  Sandy loam                                                                                         

  Les          1.13                0.7015   0.9913       81.2     1.54         0.5909   0.9783       110
  Evouettes                                                                                          
  Silt loam                                                                                          

  Wilson Sand  1.73                0.5433   0.9939       92.7     2.99         0.5346   0.9944       160
  ------------ ------------------- -------- ------------ -------- ------------ -------- ------------ ---------------

In a batch equilibrium study classified as **acceptable** (MRID
46715229), 5 or 16 hours of equilibration, 22.4-49.0%, 59.9-76.9%, and
58.1-63.5% of the applied \[^14^C\]chlormequat chloride was adsorbed to
the Breda sandy loam, Westmaas loam, and Itingen silt loam soils..
Following the second desorption step, the percent of
\[^14^C\]chlormequat chloride desorbed from the test soils, as percent
of the radioactivity adsorbed, was 40.6-68.8% for the Breda sandy loam,
21.9-34.6% for the Westmaas loam, and 20.7-55.0% for the Itingen silt
loam soils. Freundlich adsorption and desorption coefficients are listed
in the table below.

  -------------- ------------------- -------- ------------ -------- ------------ -------- ------------ ---------------
  Soil           Number range                                       Desorption                         
                 CHAPTERAdsorption                                                                     

                 K~F~                1/N      rNumber      K~Foc~   K~F~         1/N      rNumber      Number range
                                              range                                       range        CHAPTERK~Foc~
                                              CHAPTER^2^                                  CHAPTER^2^   

  Breda Sandy    2.14                0.7680   0.9998       89.4     3.18         0.7629   0.9996       133
  loam                                                                                                 

  Westmaas Loam  9.12                0.8486   0.9999       912      12.5         0.8590   0.9996       1249

  Itingen Silt   8.08                0.9553   1.0000       385      10.8         0.8618   0.9997       514
  loam                                                                                                 
  -------------- ------------------- -------- ------------ -------- ------------ -------- ------------ ---------------

*Column Leaching*

In an aged column leaching study classified as **supplemental** (MRID
46715230), following 15 days of aging, the mass balance was 98 -105% of
the applied radioactivity. Extractable and unextractable residues
accounted for 46-49 % and 18-23% of the applied, respectively.
Cumulative \[^14^C\]CO~2~ comprised 33-34% of the applied, collected on
days 7 and 15 of aging. A mass balance following the 2-day leaching
period was not determined. The pooled leachates contained 0.29-0.49% of
the applied radioactivity. Data characterizing the radioactivity in the
soil columns were not provided.

In an aged column leaching study classified as **supplemental** (MRID
124061), following 30 days of aging, 69% of the initial radioactivity
was recovered, of which 43% was recovered from the soil inside the nylon
mesh bag and 26% was recovered from the untreated soil outside of the
nylon mesh bag. Following 45 days of leaching with distilled water, an
average of 79% of the applied was recovered in the 0-3 inch segment, 2%
in the 3-6 inch segment, 1% in the 6-9 inch segment, and \<0.1% in the
9-12 inch segment. Radioactivity in the leachate volumes totaled 2.5% of
the applied. In the leachates, an average of \<0.02% of the applied was
recovered on days 0-3, 2.0% on day 4, 0.4% on day 5, 0.1% on day 6,
\<0.02% on days 8-35 days, and 0.02% on days 36-45. A maximum of 2.5% of
the applied was recovered in the leachates on days 4-6. The soil was too
coarsely sieved (12.7 mm), so that gravel might still have been present.
In addition, the temperature of the soil column during leaching was not
reported, and it was not stated whether leaching was conducted in the
dark. Also, distilled water was used which could lead to dispersion of
clays that could affect soil structure.

In an unaged column leaching study classified as **supplemental** (MRID
124062), following leaching with 20 inches of distilled water, at a rate
not exceeding 1 inch/hour, through a 15 cm column, 75-103% of the
applied was recovered in the 0-3 inch segment, 1.6-14% in the 3-6 inch
segment, 0.5-2.6% in the 6-9 inch segment, and \<0.1-1.0% in the 9-12
inch segment for the sand soil. Radioactivity in the leachate samples
was \<0.1% of the applied. The test soils were too coarsely sieved (12.7
mm) prior to use in the study, so that gravel might still have been
present. In addition, the temperature of the soil column during leaching
was not reported, and it was not stated whether leaching was conducted
in the dark. Also, distilled water was used which could lead to
dispersion of clays that could affect soil structure.

**Terrestrial Field Dissipation**

There are no acceptable data to fulfill this guideline requirement.

**Bioaccumulation**

Not required.

[]{.mark}

# Appendix II. PRZM/EXAMS Output Files

**FL turf**

stored as FLturf TR_RED.out

Chemical: chlormequat chloride

PRZM environment: FLturfC.txt modified Monday, 16 June 2003 at 12:48:06

EXAMS environment: pond298.exv modified Thuday, 29 August 2002 at
15:33:30

Metfile: w12834.dvf modified Wedday, 3 July 2002 at 08:04:28

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 53.26 47.55 31.56 16.87 14.31 4.268

1962 96.08 86.64 56.71 31.53 22.88 6.633

1963 68.32 61.26 50.6 36.67 27.78 7.914

1964 98.01 88.49 70.06 37.34 35.78 10.2

1965 153 136 102 54.05 38.18 10.79

1966 98.58 87.91 65.06 51.35 39.55 10.96

1967 81.87 73.5 49.17 26.33 19.74 5.828

1968 184 165 111 59.08 41.8 11.4

1969 63.35 56.93 50.42 32.5 23.46 6.644

1970 15.45 14.1 9.588 6.682 5.579 1.64

1971 84.94 75.54 47.7 32.64 26.74 7.588

1972 93.18 82.98 53.04 34.56 26.31 7.469

1973 9.025 8.125 7.009 5.355 4.02 1.465

1974 41.41 36.77 23.51 16.67 13.13 3.782

1975 19.95 17.66 11.74 8.305 7.126 2.086

1976 78.69 71.13 62.76 44.1 31.91 8.564

1977 61.67 56.67 37.62 18.64 14.48 4.836

1978 136 119 77.82 38.25 31 8.648

1979 122 111 75.93 39.09 33.61 9.689

1980 27.55 25.61 20.69 14.31 11.61 3.407

1981 33.94 30.62 19.29 11.34 10.08 3.6

1982 72.13 63.89 40.99 32.14 23.75 6.709

1983 153 140 116 60.28 42.66 11.76

1984 309 281 189 94.81 66.46 17.82

1985 37.9 33.24 20.43 12.77 10.3 3.147

1986 44.13 40.14 26.05 13.82 10.73 3.472

1987 15.82 13.96 10.82 7.674 6.934 2.102

1988 33.74 29.83 18.81 11.19 8.961 2.623

1989 30.26 27.57 21.14 12.25 8.819 2.416

1990 7.688 6.856 6.366 4.846 3.999 1.312

Sorted results

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

0.032258064516129 309 281 189 94.81 66.46 17.82

0.0645161290322581 184 165 116 60.28 42.66 11.76

0.0967741935483871 153 140 111 59.08 41.8 11.4

0.129032258064516 153 136 102 54.05 39.55 10.96

0.161290322580645 136 119 77.82 51.35 38.18 10.79

0.193548387096774 122 111 75.93 44.1 35.78 10.2

0.225806451612903 98.58 88.49 70.06 39.09 33.61 9.689

0.258064516129032 98.01 87.91 65.06 38.25 31.91 8.648

0.290322580645161 96.08 86.64 62.76 37.34 31 8.564

0.32258064516129 93.18 82.98 56.71 36.67 27.78 7.914

0.354838709677419 84.94 75.54 53.04 34.56 26.74 7.588

0.387096774193548 81.87 73.5 50.6 32.64 26.31 7.469

0.419354838709677 78.69 71.13 50.42 32.5 23.75 6.709

0.451612903225806 72.13 63.89 49.17 32.14 23.46 6.644

0.483870967741936 68.32 61.26 47.7 31.53 22.88 6.633

0.516129032258065 63.35 56.93 40.99 26.33 19.74 5.828

0.548387096774194 61.67 56.67 37.62 18.64 14.48 4.836

0.580645161290323 53.26 47.55 31.56 16.87 14.31 4.268

0.612903225806452 44.13 40.14 26.05 16.67 13.13 3.782

0.645161290322581 41.41 36.77 23.51 14.31 11.61 3.6

0.67741935483871 37.9 33.24 21.14 13.82 10.73 3.472

0.709677419354839 33.94 30.62 20.69 12.77 10.3 3.407

0.741935483870968 33.74 29.83 20.43 12.25 10.08 3.147

0.774193548387097 30.26 27.57 19.29 11.34 8.961 2.623

0.806451612903226 27.55 25.61 18.81 11.19 8.819 2.416

0.838709677419355 19.95 17.66 11.74 8.305 7.126 2.102

0.870967741935484 15.82 14.1 10.82 7.674 6.934 2.086

0.903225806451613 15.45 13.96 9.588 6.682 5.579 1.64

0.935483870967742 9.025 8.125 7.009 5.355 4.02 1.465

0.967741935483871 7.688 6.856 6.366 4.846 3.999 1.312

0.1 153 139.6 110.1 58.577 41.575 11.356

Average of yearly averages: 6.2924

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

Data used for this run:

Output File: FLturf TR_RED

Metfile: w12834.dvf

PRZM scenario: FLturfC.txt

EXAMS environment file: pond298.exv

Chemical Name: chlormequat chloride

Description Variable Name Value Units Comments

Molecular weight mwt 158.1 g/mol

Henry\'s Law Const. henry 1.6e-15 atm-m\^3/mol

Vapor Pressure vapr 7.5e-8 torr

Solubility sol 10e6 mg/L

Kd Kd mg/L

Koc Koc 272 mg/L

Photolysis half-life kdp 0 days Half-life

Aerobic Aquatic Metabolism kbacw 12.6 days Halfife

Anaerobic Aquatic Metabolism kbacs 0 days Halfife

Aerobic Soil Metabolism asm 100 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI cm

Application Rate: TAPP 4.15 kg/ha

Application Efficiency: APPEFF .99 fraction

Spray Drift DRFT .01 fraction of application rate applied to pond

Application Date Date 15-4 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 5 days Set to 0 or delete line for single app.

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

Interval 3 interval 5 days Set to 0 or delete line for single app.

Interval 4 interval 5 days Set to 0 or delete line for single app.

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

Interval 6 interval 5 days Set to 0 or delete line for single app.

Interval 7 interval 5 days Set to 0 or delete line for single app.

Interval 8 interval 5 days Set to 0 or delete line for single app.

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR Pond

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

**PA turf**

stored as PAturfTR_RED.out

Chemical: chlormequat chloride

PRZM environment: PAturfC.txt modified Satday, 12 October 2002 at
15:27:02

EXAMS environment: pond298.exv modified Thuday, 29 August 2002 at
15:33:30

Metfile: w14737.dvf modified Wedday, 3 July 2002 at 08:06:12

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 62.26 56.13 41.81 22.7 16.27 5.878

1962 68.36 62.26 43.4 24.06 18.81 6.969

1963 11.47 10.81 9.817 7.707 6.072 3.266

1964 20.89 19.68 17.55 13.6 11.17 3.579

1965 10.33 9.601 8.811 6.919 5.428 1.983

1966 11.6 10.95 9.901 7.616 5.912 2.653

1967 130 118 84.63 47.68 40.89 13.03

1968 109 102 75.52 46.27 38.37 11.72

1969 22.57 20.51 14.71 8.259 7.348 3.782

1970 10.99 10.3 9.386 7.378 5.893 2.466

1971 32.25 29.87 26.02 18.17 13.92 4.581

1972 157 146 108 72.84 52.78 15.6

1973 73.16 69.02 49.05 37.63 28.79 9.521

1974 51.33 48.64 40.42 28.38 21.6 7.116

1975 26.1 23.9 17.72 11.97 10.08 3.431

1976 18.71 17.31 12.1 7.344 5.88 3.273

1977 15.75 14.45 10.37 8.809 7.427 2.659

1978 53.68 51.87 42.58 24.72 18.75 5.809

1979 82.3 78.14 59.75 33.93 25.89 8.128

1980 14.42 13.42 12.65 9.357 7.295 2.485

1981 51.56 48.12 41.39 25.2 18.76 5.456

1982 96.31 90.07 71.71 48.36 35.65 10.85

1983 17.17 15.69 13.04 11.5 10.64 3.653

1984 146 137 94.63 56.14 42.91 12.22

1985 47.76 45.32 36.63 26.46 20.45 6.596

1986 38.97 36.61 27.68 20.8 16.84 5.219

1987 23.25 21.11 14.37 9.757 9.001 3.539

1988 148 140 107 59 43.12 12.46

1989 64.75 60.7 53.95 38.65 28.79 8.719

1990 123 115 81.47 45.44 35.14 10.74

Sorted results

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

0.032258064516129 157 146 108 72.84 52.78 15.6

0.0645161290322581 148 140 107 59 43.12 13.03

0.0967741935483871 146 137 94.63 56.14 42.91 12.46

0.129032258064516 130 118 84.63 48.36 40.89 12.22

0.161290322580645 123 115 81.47 47.68 38.37 11.72

0.193548387096774 109 102 75.52 46.27 35.65 10.85

0.225806451612903 96.31 90.07 71.71 45.44 35.14 10.74

0.258064516129032 82.3 78.14 59.75 38.65 28.79 9.521

0.290322580645161 73.16 69.02 53.95 37.63 28.79 8.719

0.32258064516129 68.36 62.26 49.05 33.93 25.89 8.128

0.354838709677419 64.75 60.7 43.4 28.38 21.6 7.116

0.387096774193548 62.26 56.13 42.58 26.46 20.45 6.969

0.419354838709677 53.68 51.87 41.81 25.2 18.81 6.596

0.451612903225806 51.56 48.64 41.39 24.72 18.76 5.878

0.483870967741936 51.33 48.12 40.42 24.06 18.75 5.809

0.516129032258065 47.76 45.32 36.63 22.7 16.84 5.456

0.548387096774194 38.97 36.61 27.68 20.8 16.27 5.219

0.580645161290323 32.25 29.87 26.02 18.17 13.92 4.581

0.612903225806452 26.1 23.9 17.72 13.6 11.17 3.782

0.645161290322581 23.25 21.11 17.55 11.97 10.64 3.653

0.67741935483871 22.57 20.51 14.71 11.5 10.08 3.579

0.709677419354839 20.89 19.68 14.37 9.757 9.001 3.539

0.741935483870968 18.71 17.31 13.04 9.357 7.427 3.431

0.774193548387097 17.17 15.69 12.65 8.809 7.348 3.273

0.806451612903226 15.75 14.45 12.1 8.259 7.295 3.266

0.838709677419355 14.42 13.42 10.37 7.707 6.072 2.659

0.870967741935484 11.6 10.95 9.901 7.616 5.912 2.653

0.903225806451613 11.47 10.81 9.817 7.378 5.893 2.485

0.935483870967742 10.99 10.3 9.386 7.344 5.88 2.466

0.967741935483871 10.33 9.601 8.811 6.919 5.428 1.983

0.1 144.4 135.1 93.63 55.362 42.708 12.436

Average of yearly averages: 6.57936666666666

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

Data used for this run:

Output File: PAturfTR_RED

Metfile: w14737.dvf

PRZM scenario: PAturfC.txt

EXAMS environment file: pond298.exv

Chemical Name: chlormequat chloride

Description Variable Name Value Units Comments

Molecular weight mwt 158.1 g/mol

Henry\'s Law Const. henry 1.6e-15 atm-m\^3/mol

Vapor Pressure vapr 7.5e-8 torr

Solubility sol 10e6 mg/L

Kd Kd mg/L

Koc Koc 272 mg/L

Photolysis half-life kdp 0 days Half-life

Aerobic Aquatic Metabolism kbacw 12.6 days Halfife

Anaerobic Aquatic Metabolism kbacs 0 days Halfife

Aerobic Soil Metabolism asm 100 days Halfife

Hydrolysis: pH 7 0 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI cm

Application Rate: TAPP 4.15 kg/ha

Application Efficiency: APPEFF .99 fraction

Spray Drift DRFT .01 fraction of application rate applied to pond

Application Date Date 15-4 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 5 days Set to 0 or delete line for single app.

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

Interval 3 interval 5 days Set to 0 or delete line for single app.

Interval 4 interval 5 days Set to 0 or delete line for single app.

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

Interval 6 interval 5 days Set to 0 or delete line for single app.

Interval 7 interval 5 days Set to 0 or delete line for single app.

Interval 8 interval 5 days Set to 0 or delete line for single app.

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR Pond

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

# Appendix III. TREX Model Information

*Points to Consider in Development of Risk Description for Birds and
Mammals*

**Acute and Reproduction Dietary Discussions**

The risk assessment includes numerous calculations of dietary exposure
for multiple weight classes of animals. However, there are energetic
considerations that suggest that some weight class/food item
combinations are not likely to naturally occur. For example, there are
not likely to be many 15 g mammals or 20 g birds that exclusively feed
on vegetation. The risk assessor is urged to consult such texts as the
Wildlife Exposure Factors Handbook (USEPA 1993), which provides more
comprehensive approaches to consider energy requirements and energy
availability to estimate dietary exposure. In addition, age of
individuals may also play an important role in the types and relative
amounts of food items selected. This should also be taken into account
when describing dietary risks.

**Acute Toxicity RQ Approaches**

Dose‑based and dietary‑based acute RQs should be provided to risk
managers whenever effects data allow. There are limitations to each
approach. The dose‑based approach considers that the uptake and
absorption kinetics of a gavage toxicity study to approximate exposure
associated with uptake from a dietary matrix. Toxic response is a
function of duration and intensity of exposure. For many compounds a
gavage dose represents a very short‑term high intensity exposure, where
dietary exposure may be of a more prolonged nature. The dietary‑based
approach assumes that animals in the field are consuming food at a rate
similar to that of confined laboratory animals. Energy content in food
items differs between the field and the laboratory as does the energy
requirements of wild and captive animals. The Wildlife Exposure Factors
Handbook can provide insights into energy requirements of animals in the
wild as well as energy content of their diets

**Reproduction RQ Approach**

The typical 21‑week avian reproduction study does not address the
exposure duration needed to elicit the observed responses. The study
protocol was designed to establish a steady‑state tissue concentration
for bioaccumulative compounds. For other pesticides it is entirely
possible that steady‑state tissue concentrations are achieved earlier
than the 21‑week exposure period. Moreover, pesticides may exert effects
at critical periods of the reproduction cycle and so long term exposure
may not be necessary to elicit the effect observed in the 21‑week
protocol. The EFED risk assessment uses the single‑day maximum estimated
EEC as a conservative approach. The degree to which this exposure is
conservative cannot be determined by the existing reproduction study.
However, risk assessment discussions should be accompanied by the
graphics from T‑REX model regarding the number of days dietary exposure
is above the NOAEC. The greater number of days EECs exceed the NOAEC,
the greater the confidence in predictions of reproductive risk concerns.

# Appendix IV. TerrPlant Model

Exposure to Terrestrial Plants including Wetlands (August 8, 2001;
version 1.0)

Terrestrial plants inhabiting dry and semi‑aquatic (wetland) areas may
be exposed to pesticides from runoff and/or spray drift. Semi‑aquatic
areas are low‑lying wet areas that may dry up at times throughout the
year.

EFED\'s runoff scenario is (1) based on a pesticide\'s water solubility
and the amount ot pesticide present on the soil surface and its top one
inch, (2) characterized as \"sheet runoff\" (one treated acre to an
adjacent acre) for dry areas, (3) characterized as \"channel runoff\"
(10 acres to a distant low‑lying acre) for semi‑aquatic or wetland
areas, and (4) based on percent runoff values of 0.01, 0.02, and 0.05
for water solubilities of \<10, 10‑100, and \>100 ppm, respectively.

EFED\'s Spray Drift scenario is assumed as (1) 1% for ground
application, and (2) 5% for aerial, airblast, forced air, and spray
chemigation applications. The spray drift ratio used here is in
agreement with the policy procedures at the time the worksheet was
designed.

Currently, 1) this worksheet is designed to derive the plant exposure
concentrations from a single, maximum application rate only. 2) For
pesticide applications with incorporation of depth of less than 1 inch,
the total loading EECs derived for the incorporation method will be same
as the unincorporated method.

To calculate RQ values for Non‑Endangered Terrestrial Plants:

Terrestrial Plants Inhabiting Areas Adjacent to Treatment Site:

Emergence RQ = Total Loading to Adjacent Area or EEC/Seedling Emergence
EC25

Drift RQ = Drift EEC/Vegetative Vigor EC25

Terrestrial Plants Inhabiting Semi‑aquatic Areas Adjacent to Treatment
Site:

Emergence RQ = Total Loading to Semi‑aquatic Area or EEC/Seedling
Emergence EC25 Drift RQ = Drift EEC/Vegetative Vigor EC25

To calculate RQ values for Endangered Terrestrial Plants:

Endangered Terrestrial Plants Inhabiting Areas Adjacent to Treatment
Site:

Emergence RQ = Total Loading to Adjacent Area or EEC/Seedling Emergence
EC05

Drift RQ = Drift EEC/Vegetative Vigor EC05 or NOAEC

Endangered Terrestrial Plants Inhabiting Semiaquatic Areas Near
Treatment Site:

Emergence RQ = Total Loading to Semiaquatic Area or EEC/Seedling
Emergence EC05

Drift RQ = Drift EEC/Vegetative Vigor EC05 or NOAEC

Formulas used to calculate EEC values (8/08/01; version 1.0)

To calculate EECs for terrestrial plants inhabiting in areas adjacent to
treatment sites

Un‑incorporated Ground Application (Non‑granular):

Sheet Runoff = Application Rate (lb ai/A) x Runoff Value

Drift = Application Rate (lb ai/A) x 0.01

Total Loading = EEC = Sheet Runoff + Drift

Incorporated Ground Application with Drift (Non‑granular):

Sheet Runoff = \[Application Rate (lb ai/A)/Incorporation Depth (inch)\]
x Runoff Value

Drift = Application Rate (lb ai/A) x 0.01

Total Loading = EEC = Sheet Runoff + Drift

Un‑incorporated Ground Application (Granular):

Sheet Runoff = EEC = Application Rate (lb ai/A) x Runoff Value

Incorporated Ground Application without Drift (Granular):

Sheet Runoff = EEC = \[Application Rate (lb ai/A)/Incorportion Depth
(inch)\]

x Runoff Value

Aerial/Airblast/Spray Chemigation Applications:

Sheet Runoff = Application Rate (lb ai/A) x Runoff Value x Application
Efficiency of 0.6

Drift = Application Rate (lb ai/A) x 0.05

Total Loading = EEC = Sheet Runoff + Drift

Runoff Value = 0.01, 0.02, or 0.05 when the solubility of the chemical
is \<10 ppm, 10‑100 ppm, or\>100 ppm, respectively

Incorporation Depth: Use the minimum incorporation depth reported on the
label.

# Appendix V. Individual Effect Chance Model

**Use of the Probit Dose Response Relationship to Provide Information on
the Endangered Species Levels of Concern**

**Introduction**

The document entitled Overview of Ecological Risk Assessment Process in
the Office of Pesticide Programs, U.S. Environmental Protection Agency
(USEPA 2004, the Overview Document) discusses methods for providing the
U.S. Fish and Wildlife Service (USFWS) and the National Marine Fisheries
Service (NMFS) with additional information regarding the listed animal
species acute levels of concern (LOCs). This document provides (1) the
background information on how agreements were reached between the
services and USEPA for methods to provide additional LOC information,
and (2) a discussion of issues concerning those methods and their
resolution. Risk Assessors within the Environmental Fate and Effects
Division (EFED) should use the Overview Document as well as the
following information as guidance for using the probit dose response
relationship as a tool for providing additional information on the
listed species LOCs

Effective immediately, all screening-level risk assessments (REDS,
Section 3\'s, Section 18\'s, etc.) using risk quotient (RQ) methods will
incorporate this analysis, regardless of whether listed species LOCs are
exceeded or not.

**Background on Discussion of LOCs with USFWS and NMFS**

Over the course of negotiations with the USFWS and NMFS, one topic of
discussion centered on the risk quotient values established as screening
thresholds for consideration of direct toxic effects on listed species
(i.e., the acute listed species LOCs of 0.1 and 0.05 used for
terrestrial and aquatic animals, respectively). The Agency provided the
Services with the mathematical interpretations of these LOC values,
which was documented in the background information supplied to the
Services and is included in the Overview Document CD distributed to all
employees in EFED. In short, the interpretation of the LOCs was
discussed in terms of best estimates of the chance of an individual
event (mortality or immobilization) should exposure at the estimated
environmental concentration actually occur for a species with
sensitivity to the pesticide on par with the toxicity endpoint selected
for RQ calculation.

The mathematics were based on a long-held [assumption]{.underline} of a
probit dose-response relationship for acute toxicity endpoints. The
listed species LOCs or the fraction (0.05 or 0.1) of the dose estimated
to produce 50% mortality were used to interpolate from a probit dose
response curve to estimate the associated ECx, LDx, or LCx. These values
were then used to estimate the chance of an individual event.

Two issues were identified over the course of discussions with the
Services in regard to the Agency\'s presentations of the math and the
interpretation of the LOCs. First was the issue that the chance of
individual event was highly dependant upon the assumed shape and slope
of the dose-response relationship. Second was that the Services were
unwilling to present a [generic]{.underline} threshold of the chance of
an individual event, below which the Services would not have a concern
for listed species impacts The services indicated that the baseline
conditions of a species and it\'s biology would dictate species-specific
concerns for tolerated effects. Further discussion on the confidence of
extreme value extrapolations for probit dose response did not achieve an
agreement between all parties on what the lower limit of cutoff in
reporting extreme events should be for interpretation of listed species
acute LOCs. Even consideration of using the most intolerant listed
species within taxonomic groups as a screening basis for other more
tolerant listed species was not accepted as a viable strategy for
establishing generic effects thresholds for listed species.

Consequently, it was accepted by all parties that the Agency would
provide in its risk assessments an interpretation of the listed species
LOCs in terms of the chance of an individual effect should organisms be
exposed to a media concentration or dose corresponding to 1/10 or 1/20
of the LC~50~, LD~50~, or EC~50~ used as the acute toxicity measurement
endpoint for a particular animal taxonomic group. To accomplish this
interpretation, the Agency would use (1) the slope of the dose response
relationship available from the toxicity study used to establish the
acute toxicity measurement endpoints for each animal taxonomic group;
(2) an assumption of a probit dose response relationship; (3) a mean
estimate of slope consistent with current Agency statistical procedures;
and (4) a lower limit to the estimate of individual effect chance based
on what could be calculated by Excel spreadsheet \"Normdist\" function.

**Issues with the LOC Interpretation Method and Their Resolution**

Discussion within the Agency has identified three issues with regard to
the calculation of the chance of individual event corresponding to the
listed species acute LOCs. The largest issue is the extrapolation to
extremely low probability events, referring to the very large confidence
intervals surrounding such estimates. A secondary issue, but still very
important, is the extent to which probit dose response slopes can be
calculated for existing studies (i.e., the fitting of a probit dose
response relationship to available data). The third issue is how to
proceed when information is unavailable to estimate a slope. The
following guidance information will address these issues:

[Extrapolation to Extremely Low Probability Events]{.underline}

The nature of this issue centers on the fact that slope estimates are
accompanied by a corresponding variance in the slope term. This variance
in the slope term and to some extent the variance in the median lethal
dose estimate, can result in wide variations of effects probabilities at
the upper and lower tails of the dose range. While the Agency has agreed
to present the effects probability associated with the LOCs based on the
mean estimate of slope, it is evident that expression of this single
estimate of the corresponding effects probability would suggest that the
Agency has inordinately high confidence in this estimate, when in fact
there is likely considerable variability in the estimate. Consequently,
for the short term, it is recommended that both the estimate of effects
probability be calculated for the mean slope estimate and listed species
LOC [and]{.underline} available information on the 95% confidence
interval of the slope estimate be used to calculate an upper and lower
estimate of the effects probability. It is important to note that
interpretation of these results is not required under agreement with the
Services. The Services have requested that the results be made available
in the screening assessment reports. It is recommended that reporting
minimally include the following discussion:

> \" Based on an assumption of a probit dose response relationship with
> a mean estimated slope of **(enter slope here)**, the corresponding
> estimated chance of individual mortality associated with the listed
> species LOC of (0.1 or 0.05) the acute toxic endpoint for **(enter
> appropriate animal taxonomic group)** is **(enter value)**. It is
> recognized that extrapolation of very low probability events is
> associated with considerable uncertainty in the resulting estimates.
> To explore possible bounds to such estimates, the upper and lower
> values for the mean slope estimate **(enter the 95 percent confidence
> interval for the slope)** were used to calculate upper and lower
> estimates of the effects probability associated with the listed
> species LOC. These values are **(enter the upper and lower
> estimates)**.\"

For the present time, the Excel spreadsheet tool IECV1.1 will allow for
such calculations by entering in the mean slope estimate and the 95
percent confidence bounds of that estimate as the slope parameter for
the spreadsheet. It is important to note that the model output can go as
low as 10 E-16 in estimating the event probability. This cut-off is a
limit in the Excel spreadsheet environment and is not to be interpreted
as an agreed upon lower bound threshold for concern for individual
effects in any given listed species.

*EFED will continue to work on establishing subsequent approaches to
account for both the variance in the slope and the median lethal dose
estimate when establishing this upper and lower estimates of effects
estimates associated with the listed species LOCs.*

[Probit Slopes for Existing Studies]{.underline}

Slope information may or may not be estimated for a given study upon
which RQs were calculated. When the available data evaluation records
(DERs) or study reports provide the slope information (i.e., mean slope
estimate, p-value of estimate, and 95% confidence interval of the
estimate) , it should be used as reported once these reported values
have been carefully reviewed to ensure their accuracy. However, there
are likely to be situations where slope information is not provided in
the DERs. For such situations, the raw data from the study must be
entered into and analyzed by the EFED current statistical package for
acute effects studies. See the EFED Statistical Workgroup for assistance
with accessing these software. Probit slope information will be used
from these analyses. However, there are two distinctions that must be
made in the reporting of these results for listed species evaluation.
First, studies with good probit fit characteristics can be used as
reported accompanied with a statement that the probit dose response
relationship was statistically appropriate for the data set.
Alternatively, if the assumption of a probit dose response was shown to
be statistically unsupported, the slope estimates are still used in the
listed species LOC interpretation (remember we have in our policy
assumed probit dose response when LOCs were established), but the
statistical rejection criteria must be presented along with a statement
:

> \"Although the Agency has assumed a probit dose response relationship
> in establishing the listed species LOCs, the available data for the
> toxicity study generating RQs for this taxonomic group do not
> statistically support a probit dose response relationship **(enter the
> p-value from the statistical package)** and so the confidence in
> estimated event probabilities based on this dose response relationship
> and the listed species LOC is low.\"

*EFED will continue to work on the development of statistical tools to
explore alternative dose response relationships in situations where the
assumption of probit dose response relationship is not upheld by
available data.*

[How to Proceed When Information is Unavailable to Estimate a
Slope]{.underline}

State in the assessment that information is unavailable to estimate a
slope from the available toxicity study and the reason why re-analysis
of raw data is not possible. Then state that a event probability was
calculated for the listed species LOC based on a default slope
assumption of 4.5 as per original Agency assumptions of typical slope
cited in Urban and Cook (1986).

**References**

United States Environmental Protection Agency (USEPA). 2004. Overview of
Ecological Risk Assessment Process in the Office of Pesticide Programs,
U.S. Environmental Protection Agency. Office of Prevention, Pesticides
and Toxic Substances, Office of Pesticide Programs, Washington, DC.

Urban D.J. and N.J. Cook. 1986. Hazard Evaluation Division Standard
Evaluation Procedure Ecological Risk Assessment. EPA 540/9-85-001. U.S.
Environmental Protection Agency, Office of Pesticide Programs,
Washington, DC.

# Appendix VI. Endangered Species Count from the LOCATES Database by Listed Taxon for each Crop

[]{.mark}

*Species Counts by State for Indicated Crops*

No species were excluded.

Minimum of 1 Acre.

All Medium Types Reported

*floriculture crops - bedding/garden plants, cut flowers& florist
greens,*

*foliage and potted flowering plants- total, nursery and greenhouse
crops -*

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

***Alabama***

The taxa Amphibian has 2 species co-occurring with indicated crops.

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Bivalve has 28 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 9 species co-occurring with indicated crops.

The taxa Ferns has 2 species co-occurring with indicated crops.

The taxa Fish has 15 species co-occurring with indicated crops.

The taxa Gastropod has 10 species co-occurring with indicated crops.

The taxa Mammal has 4 species co-occurring with indicated crops.

The taxa Monocot has 3 species co-occurring with indicated crops.

The taxa Reptile has 5 species co-occurring with indicated crops.

***Arizona***

The taxa Amphibian has 2 species co-occurring with indicated crops.

The taxa Bird has 8 species co-occurring with indicated crops.

The taxa Dicot has 14 species co-occurring with indicated crops.

The taxa Fish has 17 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Mammal has 8 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

The taxa Reptile has 2 species co-occurring with indicated crops.

***Arkansas***

The taxa Bird has 3 species co-occurring with indicated crops.

9/21/2006 1:45:25 PM Ver. 2.10.3 Page 1 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Bivalve has 5 species co-occurring with indicated crops.

The taxa Crustacean has 2 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

***California***

The taxa Amphibian has 6 species co-occurring with indicated crops.

The taxa Bird has 16 species co-occurring with indicated crops.

The taxa Conf/cycds has 2 species co-occurring with indicated crops.

The taxa Crustacean has 9 species co-occurring with indicated crops.

The taxa Dicot has 161 species co-occurring with indicated crops.

The taxa Fish has 29 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Insect has 22 species co-occurring with indicated crops.

The taxa Mammal has 20 species co-occurring with indicated crops.

The taxa Marine mml has 2 species co-occurring with indicated crops.

The taxa Monocot has 18 species co-occurring with indicated crops.

The taxa Reptile has 8 species co-occurring with indicated crops.

***Colorado***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Dicot has 6 species co-occurring with indicated crops.

The taxa Fish has 6 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Connecticut***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 1 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 2 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Delaware***

The taxa Bird has 2 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Florida***

The taxa Amphibian has 1 species co-occurring with indicated crops.

The taxa Bird has 10 species co-occurring with indicated crops.

The taxa Bivalve has 7 species co-occurring with indicated crops.

The taxa Conf/cycds has 1 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 49 species co-occurring with indicated crops.

The taxa Fish has 4 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Lichen has 1 species co-occurring with indicated crops.

The taxa Mammal has 13 species co-occurring with indicated crops.

The taxa Marine mml has 1 species co-occurring with indicated crops.

The taxa Monocot has 3 species co-occurring with indicated crops.

The taxa Reptile has 10 species co-occurring with indicated crops.

***Georgia***

The taxa Amphibian has 1 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 3 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Bird has 5 species co-occurring with indicated crops.

The taxa Bivalve has 16 species co-occurring with indicated crops.

The taxa Conf/cycds has 1 species co-occurring with indicated crops.

The taxa Dicot has 9 species co-occurring with indicated crops.

The taxa Ferns has 2 species co-occurring with indicated crops.

The taxa Fish has 8 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

The taxa Marine mml has 1 species co-occurring with indicated crops.

The taxa Monocot has 6 species co-occurring with indicated crops.

The taxa Reptile has 2 species co-occurring with indicated crops.

***Hawaii***

The taxa Arachnid has 1 species co-occurring with indicated crops.

The taxa Bird has 32 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 233 species co-occurring with indicated crops.

The taxa Ferns has 12 species co-occurring with indicated crops.

The taxa Gastropod has 39 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Marine mml has 1 species co-occurring with indicated crops.

The taxa Monocot has 22 species co-occurring with indicated crops.

The taxa Reptile has 2 species co-occurring with indicated crops.

***Idaho***

The taxa Bird has 1 species co-occurring with indicated crops.

The taxa Dicot has 3 species co-occurring with indicated crops.

The taxa Fish has 8 species co-occurring with indicated crops.

The taxa Gastropod has 2 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

***Illinois***

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 4 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 7 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 7 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Indiana***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 11 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Iowa***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Dicot has 3 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Fish has 2 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

***Kansas***

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Fish has 4 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 5 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Kentucky***

The taxa Bird has 7 species co-occurring with indicated crops.

The taxa Bivalve has 22 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 9 species co-occurring with indicated crops.

The taxa Fish has 3 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

***Louisiana***

The taxa Bird has 5 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Fish has 2 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Marine mml has 1 species co-occurring with indicated crops.

The taxa Reptile has 7 species co-occurring with indicated crops.

***Maine***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Fish has 2 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

***Maryland***

The taxa Bird has 2 species co-occurring with indicated crops.

The taxa Bivalve has 1 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 6 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Fish has 2 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Massachusetts***

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 3 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

The taxa Reptile has 2 species co-occurring with indicated crops.

***Michigan***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Insect has 4 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

The taxa Monocot has 3 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Minnesota***

The taxa Bird has 2 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Dicot has 2 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 7 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Monocot has 2 species co-occurring with indicated crops.

***Mississippi***

The taxa Amphibian has 1 species co-occurring with indicated crops.

The taxa Bird has 6 species co-occurring with indicated crops.

The taxa Bivalve has 7 species co-occurring with indicated crops.

The taxa Dicot has 2 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Fish has 3 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Reptile has 7 species co-occurring with indicated crops.

***Missouri***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 6 species co-occurring with indicated crops.

The taxa Dicot has 6 species co-occurring with indicated crops.

The taxa Fish has 5 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Montana***

The taxa Bird has 2 species co-occurring with indicated crops.

The taxa Dicot has 2 species co-occurring with indicated crops.

The taxa Fish has 4 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

***Nebraska***

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Fish has 2 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 8 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Nevada***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Dicot has 7 species co-occurring with indicated crops.

The taxa Fish has 15 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***New Hampshire***

The taxa Bird has 1 species co-occurring with indicated crops.

The taxa Bivalve has 1 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***New Jersey***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Dicot has 2 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 3 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***New Mexico***

The taxa Amphibian has 1 species co-occurring with indicated crops.

The taxa Bird has 7 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 10 species co-occurring with indicated crops.

The taxa Fish has 9 species co-occurring with indicated crops.

The taxa Gastropod has 2 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 9 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Mammal has 5 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***New York***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 1 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***North Carolina***

The taxa Arachnid has 1 species co-occurring with indicated crops.

The taxa Bird has 5 species co-occurring with indicated crops.

The taxa Bivalve has 8 species co-occurring with indicated crops.

The taxa Dicot has 20 species co-occurring with indicated crops.

The taxa Fish has 4 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Lichen has 1 species co-occurring with indicated crops.

The taxa Mammal has 4 species co-occurring with indicated crops.

The taxa Marine mml has 1 species co-occurring with indicated crops.

The taxa Monocot has 5 species co-occurring with indicated crops.

The taxa Reptile has 5 species co-occurring with indicated crops.

***North Dakota***

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 10 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

***Ohio***

The taxa Bird has 2 species co-occurring with indicated crops.

The taxa Bivalve has 6 species co-occurring with indicated crops.

The taxa Dicot has 3 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 4 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

The taxa Reptile has 2 species co-occurring with indicated crops.

***Oklahoma***

The taxa Bird has 6 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Fish has 4 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

***Oregon***

The taxa Bird has 5 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 11 species co-occurring with indicated crops.

The taxa Fish has 22 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

***Pennsylvania***

The taxa Bird has 2 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 11 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Reptile has 1 species co-occurring with indicated crops.

***Rhode Island***

The taxa Bird has 1 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***South Carolina***

The taxa Amphibian has 1 species co-occurring with indicated crops.

The taxa Bird has 5 species co-occurring with indicated crops.

The taxa Bivalve has 1 species co-occurring with indicated crops.

The taxa Dicot has 12 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Lichen has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Marine mml has 6 species co-occurring with indicated crops.

The taxa Monocot has 6 species co-occurring with indicated crops.

The taxa Reptile has 5 species co-occurring with indicated crops.

***South Dakota***

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Fish has 2 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Tennessee***

The taxa Arachnid has 1 species co-occurring with indicated crops.

The taxa Bird has 4 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 12 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Bivalve has 38 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 16 species co-occurring with indicated crops.

The taxa Ferns has 1 species co-occurring with indicated crops.

The taxa Fish has 16 species co-occurring with indicated crops.

The taxa Gastropod has 2 species co-occurring with indicated crops.

The taxa Lichen has 1 species co-occurring with indicated crops.

The taxa Mammal has 3 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Texas***

The taxa Amphibian has 4 species co-occurring with indicated crops.

The taxa Arachnid has 10 species co-occurring with indicated crops.

The taxa Bird has 13 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 20 species co-occurring with indicated crops.

The taxa Fish has 4 species co-occurring with indicated crops.

The taxa Insect has 8 species co-occurring with indicated crops.

The taxa Mammal has 5 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

The taxa Reptile has 6 species co-occurring with indicated crops.

***Utah***

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Dicot has 19 species co-occurring with indicated crops.

The taxa Fish has 8 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Vermont***

The taxa Bird has 1 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 13 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Bivalve has 1 species co-occurring with indicated crops.

The taxa Dicot has 1 species co-occurring with indicated crops.

The taxa Mammal has 1 species co-occurring with indicated crops.

The taxa Monocot has 1 species co-occurring with indicated crops.

***Virginia***

The taxa Amphibian has 1 species co-occurring with indicated crops.

The taxa Bird has 3 species co-occurring with indicated crops.

The taxa Bivalve has 13 species co-occurring with indicated crops.

The taxa Crustacean has 1 species co-occurring with indicated crops.

The taxa Dicot has 12 species co-occurring with indicated crops.

The taxa Fish has 5 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Insect has 3 species co-occurring with indicated crops.

The taxa Mammal has 5 species co-occurring with indicated crops.

The taxa Monocot has 4 species co-occurring with indicated crops.

The taxa Reptile has 1 species co-occurring with indicated crops.

***Washington***

The taxa Bird has 5 species co-occurring with indicated crops.

The taxa Dicot has 7 species co-occurring with indicated crops.

The taxa Fish has 18 species co-occurring with indicated crops.

The taxa Insect has 1 species co-occurring with indicated crops.

The taxa Mammal has 4 species co-occurring with indicated crops.

***West Virginia***

The taxa Amphibian has 1 species co-occurring with indicated crops.

The taxa Bird has 1 species co-occurring with indicated crops.

The taxa Bivalve has 5 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

The taxa Gastropod has 1 species co-occurring with indicated crops.

The taxa Mammal has 4 species co-occurring with indicated crops.

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 14 of 15

AL, AK, AZ, AR, CA, CO, CT, DE, DC, FL, GA, HI, ID, IL, IN, IA, KS, KY,
LA, ME, MD, MA, MI, MN,

MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, OH, OK, OR, PA, PR, RI, SC,
SD, TN, TX, UT, VT,

VA, WA, WV, WI, WY

The taxa Monocot has 1 species co-occurring with indicated crops.

***Wisconsin***

The taxa Bird has 4 species co-occurring with indicated crops.

The taxa Bivalve has 2 species co-occurring with indicated crops.

The taxa Dicot has 4 species co-occurring with indicated crops.

The taxa Insect has 2 species co-occurring with indicated crops.

The taxa Mammal has 2 species co-occurring with indicated crops.

The taxa Monocot has 2 species co-occurring with indicated crops.

***Wyoming***

The taxa Bird has 1 species co-occurring with indicated crops.

The taxa Dicot has 2 species co-occurring with indicated crops.

The taxa Fish has 1 species co-occurring with indicated crops.

The taxa Mammal has 4 species co-occurring with indicated crops.

**No species were excluded.**

**Dispersed species included in report.**

9/21/2006 1:45:26 PM Ver. 2.10.3 Page 15 of 15

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