**UNITED STATES ENVIRONMENTAL PROTECTION
AGENCY**![](media/image1.png){width="1.073611111111111in"
height="1.0944444444444446in"}

**WASHINGTON, D.C. 20460-0001**

**OFFICE OF**

**PREVENTION, PESTICIDES**

**AND TOXIC SUBSTANCES**

> DP Barcode: D336709
>
> PC Code: 018101
>
> Date: 04/11/2007

**SUBJECT:** Environmental Fate and Ecological Risk Assessment in
Support of the Reregistration Eligibility Decision for Chlormequat
Chloride

**TO:** Robert McNally, Risk Manager

Tracy Perry, Risk Review Manager

Special Review and Reregistration Division (7508P)

**FROM:** Brian D. Kiernan, Biologist

Marietta Echeverria, Environmental Scientist

Environmental Risk Branch IV

> Environmental Fate and Effects Division (7507P)

**APPROVED**

**BY:** Elizabeth Behl, Branch Chief

Environmental Risk Branch IV

> Environmental Fate and Effects Division (7507P)

The Environmental Fate and Effects Division (EFED) has completed an
environmental fate and ecological risk assessment chapter in support of
the reregistration eligibility decision for chlormequat chloride
(Cycocel^®^; EPA Reg. No. 241-74). An environmental risk assessment in
support of a Section 3 registration for use on containerized nursery
crops and bedding plants was completed last year (DP Barcode D333104),
and the only difference is a lower application rate. Based on current
label uses at maximum rates there are potential risks to birds,
reptiles, terrestrial-phase amphibians, mammals, and both terrestrial
and aquatic plants. No chronic toxicity data are available for aquatic
vertebrates; therefore, the potential chronic risks to fish and
aquatic-phase amphibians cannot be evaluated and is presumed.

Table 1 lists the status of the ecological effect dataset. A major
deficiency is the lack of a no-observed adverse effect concentration
(NOAEC) for avian reproduction. Table 2 lists the status of the fate
dataset. Major deficiencies include the lack of hydrolysis, photolysis
and anaerobic soil metabolism data, as well as unidentified
transformation products in the aerobic soil and aerobic aquatic
metabolism studies.

This assessment also assumes that chlormequat chloride will be applied
by low-boom sprayer to bedding plants and by back-pack sprayer to most
containerized ornamentals. If this assumption is not supported by the
registrant, spray drift and runoff estimates may be affected.

**Recommended label language:**

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

"Do not apply directly to water, or to areas where surface water is
present or to intertidal areas below the mean high water mark. Do not
contaminate water when disposing of equipment washwater or rinsate.\"

"Drift and runoff may be hazardous to aquatic organisms in water
adjacent to treated areas."

**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.

Table 1. Status of ecological data requirements for chlormequat
chloride.

+--------+-------+-----------------------+----------+-----------------+
| DATA   |       |                       | Adequate | CITATION:       |
| REQUI  |       |                       | for      |                 |
| REMENT |       |                       | Ec       | MRID or ECOTOX  |
|        |       |                       | ological |                 |
|        |       |                       | Risk     |                 |
|        |       |                       | As       |                 |
|        |       |                       | sessment |                 |
+========+=======+=======================+==========+=================+
| 85     | 71-1A | Avian Acute Oral      | \-       | \-              |
| 0.2100 |       | Toxicity              |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| N      |       | Avian Acute Oral      | Yes      | 467152-11;      |
| on-gui |       | Toxicity              |          | supplemental    |
| deline |       |                       |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 71-2A | Avian Dietary         | Yes      | 467152-122;     |
| 0.2200 |       | Toxicity - Quail      |          | supplemental    |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 71-2B | Avian Dietary         | Yes      | 467152-13;      |
| 0.2200 |       | Toxicity - Duck       |          | acceptable      |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 71‑4A | Avian Reproduction -  | \-       | \-              |
| 0.2300 |       | Quail                 |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 71‑4B | Avian Reproduction -  | \-       | \-              |
| 0.2300 |       | Duck                  |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| N      |       | Avian Reproduction -  | No       | 467152-14;      |
| on-gui |       | Quail                 |          | supplemental    |
| deline |       |                       |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-1A | Fish Acute Toxicity   | Yes      | 001232-61;      |
| 0.1075 |       | Bluegill              |          | acceptable      |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-1B | Fish Acute Toxicity   | Yes      | 000374-33;      |
| 0.1075 |       | Fathead Minnow        |          | acceptable      |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-1C | Fish Acute Toxicity   | \-       | \-              |
| 0.1075 |       | Rainbow Trout         |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| N      |       | Fish Acute Toxicity   | Yes      | 467152-17;      |
| on-gui |       | Rainbow Trout         |          | supplemental    |
| deline |       |                       |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-2A | Invertebrate Acute    | Yes      | 001387-19;      |
| 0.1010 |       | Daphnid Toxicity      |          | supplemental    |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-3A | Estuarine/Marine      | Yes      | ECOTOX          |
| 0.1075 |       | Toxicity - Fish       |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-3B | Estuarine/Marine      | \-       | \-              |
| 0.1025 |       | Toxicity - Mollusk    |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-3C | Estuarine/Marine      | Yes      | ECOTOX          |
| 0.1035 |       | Acute Toxicity        |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-4A | Daphnid Chronic       | Yes      | 467152-16;      |
| 0.1300 |       | Toxicity (life cycle) |          | supplemental    |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-4B | Estuarine/Marine      | \-       | \-              |
| 0.1350 |       | Invertebrate chronic  |          |                 |
|        |       | (Mysid Shrimp, Life   |          |                 |
|        |       | Cycle)                |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-4C | Freshwater Fish-      | No       | Data gap        |
| 0.1400 |       | Early Life Stage      |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 72-4D | Estuarine Fish- Early | \-       | \-              |
| 0.1400 |       | Life Stage            |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 1     | Terrestrial Plant     | \-       | \-              |
| 0.4100 | 23-1A | Toxicity, Seedling    |          |                 |
|        |       | Emergence             |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| N      |       | Terrestrial Plant     | Yes      | 467152-19;      |
| on-gui |       | Toxicity, Seedling    |          | supplemental    |
| deline |       | Emergence             |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 1     | Terrestrial Plant     | \-       | \-              |
| 0.4150 | 23-1B | Toxicity, Vegetative  |          |                 |
|        |       | Vigor                 |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| N      |       | Terrestrial Plant     | No       | 467152-20;      |
| on-gui |       | Toxicity, Vegetative  |          | supplemental    |
| deline |       | Vigor                 |          |                 |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 123-2 | Aquatic Plant Growth- | Yes      | 467152-21;      |
| 0.4400 |       | *Lemna*               |          | acceptable      |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 123-2 | Aquatic Plant Growth- | Yes      | 467152-22;      |
| 0.4500 |       | Algae                 |          | acceptable      |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 123-2 | Aquatic Plant Growth- | Yes      | 467152-23;      |
| 0.4550 |       | Cyanobacteria         |          | supplemental    |
+--------+-------+-----------------------+----------+-----------------+
| 85     | 141-1 | Honey Bee Acute       | Yes      | 467152-24;      |
| 0.3020 |       | Contact               |          | acceptable      |
+--------+-------+-----------------------+----------+-----------------+

Table 2. Status of environmental fate and transport data requirements
for chlormequat chloride.

+--------------------------------------+-------------------------------+
| **Data Requirement and Guideline     | # Adequate f                  |
| Reference Number**                   | or Ecological Risk Assessment |
+--------------------------------------+-------------------------------+
| #                                    | No^1^                         |
|                                      |                               |
| # Degradation - Lab                  | No^2^                         |
|                                      |                               |
| 161-1 Hydrolysis                     | NA                            |
|                                      |                               |
| 161-2 Photolysis in Water            | NA                            |
|                                      |                               |
| 161-3 Photolysis in Soil             |                               |
|                                      |                               |
| 161-4 Photodegradation in Air        |                               |
+--------------------------------------+-------------------------------+
| # Metabolism Studies -- Lab          | No^3^                         |
|                                      |                               |
| 162-1 Aerobic Soil Metabolism        | No                            |
|                                      |                               |
| 162-2 Anaerobic Soil Metabolism      | NA                            |
|                                      |                               |
| 162-3 Anaerobic Aquatic Metabolism   | No^4^                         |
|                                      |                               |
| 162-4 Aerobic Aquatic Metabolism     |                               |
+--------------------------------------+-------------------------------+
| # Mobility Studies -- Lab            | Yes (MRIDs 46715228,          |
|                                      | 46715229)                     |
| 163-1 Leaching and                   |                               |
| Adsoprtion/Desorption                | NA\                           |
|                                      | NA                            |
| 163-2 Volatility from Soil (Lab)     |                               |
|                                      |                               |
| 163-3 Volatility from Soil (Field)   |                               |
+--------------------------------------+-------------------------------+
| # Field Dissipation Studies          | No                            |
|                                      |                               |
| 164-1 Terrestrial                    | NA                            |
|                                      |                               |
| 164-2 Aquatic                        | NA                            |
|                                      |                               |
| 164-3 Forestry                       | NA                            |
|                                      |                               |
| 164-4 Combination and tank mixes     | NA                            |
|                                      |                               |
| 164-5 Terrestrial (Long-Term)        |                               |
+--------------------------------------+-------------------------------+
| # Accumulation Studies               | NA                            |
|                                      |                               |
| 165-1 In Confined Rotational Crops   | NA                            |
|                                      |                               |
| 165-2 In Field Rotational Crops      | NA                            |
|                                      |                               |
| 165-3 In Irrigated Crops             | No                            |
|                                      |                               |
| 165-4 In Fish                        | NA                            |
|                                      |                               |
| 165-5 Aquatic Non-Target Organisms   |                               |
+--------------------------------------+-------------------------------+

1.  MRID 124063 is classified as unacceptable

2.  MRID 124063 is classified as unacceptable

3.  MRID 46715225 is classified as supplemental because all
    transformation \> 10% may not have been identified.

4.  MRID 46715227 is classified as supplemental because all
    transformation \> 10% may not have been identified.