> **U.S. ENVIRONMENTAL PROTECTION AGENCY**
> ![](media/image1.png){width="1.3506944444444444in"
> height="1.3506944444444444in"}
>
> WASHINGTON D.C., 20460
>
> OFFICE OF
>
> PREVENTION, PESTICIDES AND
>
> TOXIC SUBSTANCES
>
> **PC Code:** 055801
>
> **DP Barcodes:** 3511118

**[MEMORANDUM]{.underline}** **DATE:** April 21 2008

**SUBJECT:** Revised Ecological Risk Assessment for Reregistration
Eligibility Decision (RED) for Naphthalene

**FROM:** Stephen Carey, Biologist

Mark Corbin, Senior Environmental Scientist

Environmental Risk Branch III

Environmental Fate and Effects Division (7507P)

**TO:** Molly Clayton

Reregistration Branch

Special Review and Reregistration Division (7508P)

**REVIEWED**

**BY:** Pamela Hurley, Toxicologist

James Hetrick, Senior Scientist

Environmental Risk Branch III

Environmental Fate and Effects Division 7507P

**APPROVED**

**BY:** Karen Whitby, Branch Chief

Environmental Risk Branch III

Environmental Fate and Effects Division 7507P

The Environmental Fate and Effects Division (EFED) has completed the
environmental fate and ecological risk assessment in support of the
re-registration of the repellent, Naphthalene (CAS Registry Number:
91-20-3); End Use Products - ENOZ® Skat! -- white solid flakes/crystals
(granular) containing 99.45% active ingredient (a.i.) \[EPA Reg. No.
1475-146\]; Snake-A-Way -- white solid flakes/crystals (granular)
containing 7.0% ai \[EPA Reg. No. 58630-1\]; Shotgun® Rabbit & Dog
Repellent -- white solid flakes/crystals (granular) containing 15.0% ai
\[EPA Reg. No. 4-465\]; and Bat-A-Way Bird, Squirrel, Rabbit & Bat
Repellent - white solid flakes/crystals (granular) containing 99.95%
active ingredient \[EPA Reg. No. 58630-2\], for use to repel unwanted
animal visitors from flowering beds, buildings, and gardens in
non-cropped and domestic outdoor areas. Conclusions regarding the
environmental fate, ecological effects, and ecological risks associated
with the proposed use in residential areas can be found in the Executive
Summary of the attached document.

**Data Gaps**

[]{.mark}

**Table A.1.** identifies the status of environmental fate and transport
study requirements and **Table A.2.** identifies the status of
ecological effects study requirements.

+----------+------------+---------+-------------+--------------------+
| **Table  |            |         |             |                    |
| A.1      |            |         |             |                    |
| Envir    |            |         |             |                    |
| onmental |            |         |             |                    |
| Fate     |            |         |             |                    |
| Data     |            |         |             |                    |
| Requ     |            |         |             |                    |
| irements |            |         |             |                    |
| for      |            |         |             |                    |
| Napht    |            |         |             |                    |
| halene** |            |         |             |                    |
+==========+============+=========+=============+====================+
| **G      | **Data     | **MRID  | **Study     | **Are more data    |
| uideline | Req        | \#**    | Class       | needed?**          |
| \#**     | uirement** |         | ification** |                    |
+----------+------------+---------+-------------+--------------------+
| 161-1    | Hydrolysis | Not     | Not         | No. Published      |
|          |            | av      | available   | literature         |
|          |            | ailable |             | suggests this is   |
|          |            |         |             | an insignificant   |
|          |            |         |             | route of           |
|          |            |         |             | dissipation.       |
+----------+------------+---------+-------------+--------------------+
| 161-2    | Photod     | Not     | Not         | No. Published      |
|          | egradation | av      | available   | literature         |
|          | in Water   | ailable |             | suggests this is   |
|          |            |         |             | an insignificant   |
|          |            |         |             | route of           |
|          |            |         |             | dissipation.       |
+----------+------------+---------+-------------+--------------------+
| 161-3    | Photod     | Not     | Not         | No. Published      |
|          | egradation | av      | available   | literature         |
|          | on Soil    | ailable |             | suggests this is   |
|          |            |         |             | an insignificant   |
|          |            |         |             | route of           |
|          |            |         |             | dissipation and    |
|          |            |         |             | this is not a      |
|          |            |         |             | model input.       |
+----------+------------+---------+-------------+--------------------+
| 161-4    | Photod     | Not     | Not         | No                 |
|          | egradation | av      | available   |                    |
|          | in Air     | ailable |             |                    |
+----------+------------+---------+-------------+--------------------+
| 162-1    | Aerobic    | Not     | Not         | Yes. Model         |
|          | Soil       | av      | available   | assumptions based  |
|          | Metabolism | ailable |             | on the             |
|          |            |         |             | supplemental data  |
|          |            |         |             | from the open      |
|          |            |         |             | literature.        |
|          |            |         |             | Submission of      |
|          |            |         |             | acceptable data    |
|          |            |         |             | can provide for    |
|          |            |         |             | confirmation of    |
|          |            |         |             | assumptions or     |
|          |            |         |             | inputs for refined |
|          |            |         |             | modeling.          |
+----------+------------+---------+-------------+--------------------+
| 162-2    | Anaerobic  | Not     | Not         | No                 |
|          | Soil       | av      | available   |                    |
|          |            | ailable |             |                    |
|          | Metabolism |         |             |                    |
+----------+------------+---------+-------------+--------------------+
| 162-3    | Anaerobic  | Not     | Not         | No                 |
|          | Aquatic    | av      | available   |                    |
|          | Metabolism | ailable |             |                    |
+----------+------------+---------+-------------+--------------------+
| 162-4    | Aerobic    | Not     | Not         | Yes. Lack of data  |
|          | Aquatic    | av      | available   | led to the         |
|          | Metabolism | ailable |             | assumption of half |
|          |            |         |             | life at two times  |
|          |            |         |             | the aerobic soil   |
|          |            |         |             | metabolism value.  |
|          |            |         |             | Submission of data |
|          |            |         |             | can remove         |
|          |            |         |             | uncertainty in     |
|          |            |         |             | this assumption.   |
+----------+------------+---------+-------------+--------------------+
| 163-1    | Soil       | Not     | Not         | Yes. Supplemental  |
|          | Column     | av      | available   | data from open     |
|          | Leaching   | ailable |             | literature. Model  |
|          |            |         |             | assumptions were   |
|          | (Aged)     |         |             | based on these     |
|          |            |         |             | supplemental data. |
|          | A          |         |             | Submission of      |
|          | dsorption/ |         |             | acceptable data    |
|          | Desorption |         |             | can provide for    |
|          |            |         |             | confirmation of    |
|          | (parent)   |         |             | assumptions or     |
|          |            |         |             | inputs for refined |
|          |            |         |             | modeling.          |
+----------+------------+---------+-------------+--------------------+
| 163-2    | Laboratory | Not     | Not         | No                 |
|          | Volatility | av      | available   |                    |
|          |            | ailable |             |                    |
+----------+------------+---------+-------------+--------------------+
| 163-3    | Field      | Not     | Not         | No                 |
|          | Volatility | av      | available   |                    |
|          |            | ailable |             |                    |
+----------+------------+---------+-------------+--------------------+
| 164-1    | T          | Not     | Not         | No.                |
|          | errestrial | av      | available   |                    |
|          | Field      | ailable |             |                    |
|          | D          |         |             |                    |
|          | issipation |         |             |                    |
+----------+------------+---------+-------------+--------------------+
| 164-2    | Aquatic    | Not     | Not         | No                 |
|          | Field      | av      | available   |                    |
|          | D          | ailable |             |                    |
|          | issipation |         |             |                    |
+----------+------------+---------+-------------+--------------------+
| 164-3    | Forestry   | Not     | Not         | No                 |
|          | D          | av      | available   |                    |
|          | issipation | ailable |             |                    |
+----------+------------+---------+-------------+--------------------+
| 165-4    | Ac         | Not     | Not         | No                 |
|          | cumulation | av      | available   |                    |
|          | in Fish    | ailable |             |                    |
+----------+------------+---------+-------------+--------------------+
| 165-5    | Ac         | Not     | Not         | No                 |
|          | cumulation | av      | available   |                    |
|          | in aquatic | ailable |             |                    |
|          | non-target |         |             |                    |
|          | organism   |         |             |                    |
|          | (crayfish) |         |             |                    |
+----------+------------+---------+-------------+--------------------+
| 166-1    | Ground     | Not     | Not         | No                 |
|          | Water-     | av      | available   |                    |
|          | small      | ailable |             |                    |
|          |            |         |             |                    |
|          | scale      |         |             |                    |
|          | p          |         |             |                    |
|          | rospective |         |             |                    |
+----------+------------+---------+-------------+--------------------+

+-------+-----------+--------+-------+---------+---------------------+
| **    |           |        |       |         |                     |
| Table |           |        |       |         |                     |
| A.2   |           |        |       |         |                     |
| Ecolo |           |        |       |         |                     |
| gical |           |        |       |         |                     |
| Ef    |           |        |       |         |                     |
| fects |           |        |       |         |                     |
| Data  |           |        |       |         |                     |
| Re    |           |        |       |         |                     |
| quire |           |        |       |         |                     |
| ments |           |        |       |         |                     |
| for   |           |        |       |         |                     |
| Nap   |           |        |       |         |                     |
| hthal |           |        |       |         |                     |
| ene** |           |        |       |         |                     |
+=======+===========+========+=======+=========+=====================+
| **G   | **Data    | **Test | **M   | **Study | **Are More Data     |
| uidel | Requ      | Mate   | RID** | Cl      | Needed?**           |
| ine** | irement** | rial** |       | assific |                     |
|       |           |        |       | ation** |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 71-1  | Avian     | Napht  | 1     | Suppl   | Yes. The purity of  |
|       | Oral      | halene | 48176 | emental | the active          |
|       | LD~50~    |        |       |         | ingredient needs to |
|       |           |        |       |         | be reported to      |
|       |           |        |       |         | upgrade the study   |
|       |           |        |       |         | to acceptable from  |
|       |           |        |       |         | supplemental.       |
+-------+-----------+--------+-------+---------+---------------------+
| 71-2  | Avian     | Napht  | 1     | Suppl   | Yes. The purity of  |
|       | Dietary   | halene | 48175 | emental | the active          |
|       | LC~50~    |        |       |         | ingredient in the   |
|       |           |        | Not   | Not     | bobwhite quail test |
|       |           |        | avai  | av      | needs to be         |
|       |           |        | lable | ailable | reported to upgrade |
|       |           |        |       |         | the study to        |
|       |           |        |       |         | acceptable from     |
|       |           |        |       |         | supplemental. A     |
|       |           |        |       |         | subacute dietary    |
|       |           |        |       |         | study with the      |
|       |           |        |       |         | mallard duck is     |
|       |           |        |       |         | required to         |
|       |           |        |       |         | determine the       |
|       |           |        |       |         | toxicity of         |
|       |           |        |       |         | naphthalene to      |
|       |           |        |       |         | waterfowl. Together |
|       |           |        |       |         | the studies would   |
|       |           |        |       |         | fulfill the 72-1    |
|       |           |        |       |         | guideline (subacute |
|       |           |        |       |         | avian dietary       |
|       |           |        |       |         | toxicity tests with |
|       |           |        |       |         | an upland game bird |
|       |           |        |       |         | and waterfowl) for  |
|       |           |        |       |         | an outdoor noncrop  |
|       |           |        |       |         | use.                |
+-------+-----------+--------+-------+---------+---------------------+
| 71-4  | Avian     | Napht  | Not   | Not     | No                  |
|       | Rep       | halene | avai  | av      |                     |
|       | roduction |        | lable | ailable |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 72-1  | F         | Napht  | 450   | Suppl   | No. Even though the |
|       | reshwater | halene | 30801 | emental | study is not        |
|       | Fish      |        |       |         | repairable, the     |
|       | LC~50~    |        | 443   | Acc     | 72-1 guideline has  |
|       |           |        | 02701 | eptable | been fulfilled for  |
|       |           |        |       |         | a toxicity test     |
|       |           |        |       |         | with a warm water   |
|       |           |        |       |         | and cold water      |
|       |           |        |       |         | fish.               |
|       |           |        |       |         |                     |
|       |           |        |       |         | No                  |
+-------+-----------+--------+-------+---------+---------------------+
| 72-2  | F         | Napht  | 443   | Acc     | No                  |
|       | reshwater | halene | 02702 | eptable |                     |
|       | Inv       |        |       |         |                     |
|       | ertebrate |        |       |         |                     |
|       | Acute     |        |       |         |                     |
|       | LC~50~    |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 72    | Estuari   | Napht  | Not   | Not     | No                  |
| -3(a) | ne/Marine | halene | avai  | av      |                     |
|       | Fish      |        | lable | ailable |                     |
|       | LC~50~    |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 72    | Estuari   | Napht  | Not   | Not     | No                  |
| -3(b) | ne/Marine | halene | avai  | av      |                     |
|       | Mollusk   |        | lable | ailable |                     |
|       | EC~50~    |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 72    | Estuari   | Napht  | Not   | Not     | No                  |
| -3(c) | ne/Marine | halene | avai  | av      |                     |
|       | Shrimp    |        | lable | ailable |                     |
|       | EC~50~    |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 72    | F         | Napht  | 462   | Suppl   | No. However, the    |
| -4(a) | reshwater | halene | 20970 | emental | non-guideline study |
|       | Fish      |        |       |         | was conducted with  |
|       | Early     |        |       |         | salmon fry instead  |
|       | L         |        |       |         | of eggs.            |
|       | ife-Stage |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 72    | Aquatic   | Napht  | Not   | Not     | No                  |
| -4(b) | Inv       | halene | avai  | av      |                     |
|       | ertebrate |        | lable | ailable |                     |
|       | L         |        |       |         |                     |
|       | ife-Cycle |        |       |         |                     |
|       | (fr       |        |       |         |                     |
|       | eshwater) |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
| 123   | Seedling  | Napht  | Not   | Not     | Yes. Product        |
| -1(a) | Emergence | halene | avai  | av      | labels, summary     |
|       |           |        | lable | ailable | reviews of          |
|       | (Tier I)  |        |       |         | available open      |
|       |           |        |       |         | literature data,    |
|       |           |        |       |         | and toxicity tests  |
|       |           |        |       |         | with green algae    |
|       |           |        |       |         | suggest naphthalene |
|       |           |        |       |         | is phytotoxic to    |
|       |           |        |       |         | plants. A Tier I    |
|       |           |        |       |         | seedling emergence  |
|       |           |        |       |         | toxicity test is    |
|       |           |        |       |         | recommended to      |
|       |           |        |       |         | determine the       |
|       |           |        |       |         | toxicity of         |
|       |           |        |       |         | naphthalene to      |
|       |           |        |       |         | terrestrial plants. |
|       |           |        |       |         | If plants are       |
|       |           |        |       |         | sensitive to        |
|       |           |        |       |         | naphthalene, there  |
|       |           |        |       |         | might be direct     |
|       |           |        |       |         | effects to plants   |
|       |           |        |       |         | and possible        |
|       |           |        |       |         | indirect effects to |
|       |           |        |       |         | animal taxa due to  |
|       |           |        |       |         | loss of cover or    |
|       |           |        |       |         | food sources.       |
|       |           |        |       |         | However, the        |
|       |           |        |       |         | likelihood for      |
|       |           |        |       |         | plants to be at     |
|       |           |        |       |         | risk from           |
|       |           |        |       |         | naphthalene is low  |
|       |           |        |       |         | but cannot be       |
|       |           |        |       |         | precluded at this   |
|       |           |        |       |         | time.               |
+-------+-----------+--------+-------+---------+---------------------+
| 123   | V         | Napht  | Not   | Not     | Yes. Product        |
| -1(b) | egetative | halene | avai  | av      | labels, summary     |
|       | Vigor     |        | lable | ailable | reviews of          |
|       | (Tier I)  |        |       |         | available open      |
|       |           |        |       |         | literature data,    |
|       |           |        |       |         | and toxicity tests  |
|       |           |        |       |         | with green algae    |
|       |           |        |       |         | suggest naphthalene |
|       |           |        |       |         | is phytotoxic to    |
|       |           |        |       |         | plants. A Tier I    |
|       |           |        |       |         | vegetative vigor    |
|       |           |        |       |         | toxicity test is    |
|       |           |        |       |         | recommended to      |
|       |           |        |       |         | determine the       |
|       |           |        |       |         | toxicity of         |
|       |           |        |       |         | naphthalene to      |
|       |           |        |       |         | terrestrial plants. |
|       |           |        |       |         | If plants are       |
|       |           |        |       |         | sensitive to        |
|       |           |        |       |         | naphthalene, there  |
|       |           |        |       |         | might be direct     |
|       |           |        |       |         | effects to plants   |
|       |           |        |       |         | and possible        |
|       |           |        |       |         | indirect effects to |
|       |           |        |       |         | animal taxa due to  |
|       |           |        |       |         | loss of cover or    |
|       |           |        |       |         | food sources.       |
|       |           |        |       |         | However, the        |
|       |           |        |       |         | likelihood for      |
|       |           |        |       |         | plants to be at     |
|       |           |        |       |         | risk from           |
|       |           |        |       |         | naphthalene is low  |
|       |           |        |       |         | but cannot be       |
|       |           |        |       |         | precluded at this   |
|       |           |        |       |         | time.               |
+-------+-----------+--------+-------+---------+---------------------+
| 123-2 | Green     | Napht  | Not   | Not     | No                  |
|       | Algae     | halene | avai  | av      |                     |
| Aq    |           |        | lable | ailable |                     |
| uatic |           |        |       |         |                     |
| Plant |           |        |       |         |                     |
| G     |           |        |       |         |                     |
| rowth |           |        |       |         |                     |
|       |           |        |       |         |                     |
| (Tier |           |        |       |         |                     |
| I and |           |        |       |         |                     |
| II)   |           |        |       |         |                     |
+-------+-----------+--------+-------+---------+---------------------+
|       | Duckweed, | Napht  | Not   | Not     | Product labels,     |
|       | Lemna     | halene | avai  | av      | summary reviews of  |
|       | gibba     |        | lable | ailable | available open      |
|       |           |        |       |         | literature data,    |
|       |           |        |       |         | and toxicity tests  |
|       |           |        |       |         | with green algae    |
|       |           |        |       |         | suggest naphthalene |
|       |           |        |       |         | is phytotoxic to    |
|       |           |        |       |         | plants. A Tier I    |
|       |           |        |       |         | aquatic vascular    |
|       |           |        |       |         | plant toxicity test |
|       |           |        |       |         | is recommended to   |
|       |           |        |       |         | determine the       |
|       |           |        |       |         | toxicity of         |
|       |           |        |       |         | naphthalene to      |
|       |           |        |       |         | vascular plants. If |
|       |           |        |       |         | plants are          |
|       |           |        |       |         | sensitive to        |
|       |           |        |       |         | naphthalene, there  |
|       |           |        |       |         | might be direct     |
|       |           |        |       |         | effects to plants   |
|       |           |        |       |         | and possible        |
|       |           |        |       |         | indirect effect to  |
|       |           |        |       |         | animal taxa due to  |
|       |           |        |       |         | loss of cover or    |
|       |           |        |       |         | food sources.       |
|       |           |        |       |         | However, the        |
|       |           |        |       |         | likelihood for      |
|       |           |        |       |         | plants to be at     |
|       |           |        |       |         | risk from           |
|       |           |        |       |         | naphthalene is low  |
|       |           |        |       |         | but cannot be       |
|       |           |        |       |         | precluded at this   |
|       |           |        |       |         | time.               |
+-------+-----------+--------+-------+---------+---------------------+
|       | F         | Napht  | Not   | Not     | Reserved. A Tier II |
|       | reshwater | halene | avai  | av      | toxicity test with  |
|       | Diatom,   |        | lable | ailable | a freshwater diatom |
|       | Navicula  |        |       |         | is recommended if   |
|       |           |        |       |         | testing with        |
|       |           |        |       |         | terrestrial plants  |
|       |           |        |       |         | raises any concerns |
|       |           |        |       |         | and/or if open      |
|       |           |        |       |         | literature data     |
|       |           |        |       |         | with freshwater     |
|       |           |        |       |         | diatoms are         |
|       |           |        |       |         | unavailable. If     |
|       |           |        |       |         | plants are          |
|       |           |        |       |         | sensitive to        |
|       |           |        |       |         | naphthalene, there  |
|       |           |        |       |         | might be direct     |
|       |           |        |       |         | effects to plants   |
|       |           |        |       |         | and possible        |
|       |           |        |       |         | indirect effect to  |
|       |           |        |       |         | animal taxa due to  |
|       |           |        |       |         | loss of cover or    |
|       |           |        |       |         | food sources.       |
|       |           |        |       |         | However, the        |
|       |           |        |       |         | likelihood for      |
|       |           |        |       |         | plants to be at     |
|       |           |        |       |         | risk from           |
|       |           |        |       |         | naphthalene is low  |
|       |           |        |       |         | but cannot be       |
|       |           |        |       |         | precluded at this   |
|       |           |        |       |         | time.               |
+-------+-----------+--------+-------+---------+---------------------+
|       | Marine    | Napht  | Not   | Not     | Reserved. A Tier II |
|       | Diatom    | halene | avai  | av      | toxicity test with  |
|       |           |        | lable | ailable | a marine diatom is  |
|       |           |        |       |         | recommended if      |
|       |           |        |       |         | testing with        |
|       |           |        |       |         | terrestrial plants  |
|       |           |        |       |         | raises any concerns |
|       |           |        |       |         | and/or if open      |
|       |           |        |       |         | literature data     |
|       |           |        |       |         | with marine diatoms |
|       |           |        |       |         | are unavailable. If |
|       |           |        |       |         | plants are          |
|       |           |        |       |         | sensitive to        |
|       |           |        |       |         | naphthalene, there  |
|       |           |        |       |         | might be direct     |
|       |           |        |       |         | effects to plants   |
|       |           |        |       |         | and possible        |
|       |           |        |       |         | indirect effect to  |
|       |           |        |       |         | animal taxa due to  |
|       |           |        |       |         | loss of cover or    |
|       |           |        |       |         | food sources.       |
|       |           |        |       |         | However, the        |
|       |           |        |       |         | likelihood for      |
|       |           |        |       |         | plants to be at     |
|       |           |        |       |         | risk from           |
|       |           |        |       |         | naphthalene is low  |
|       |           |        |       |         | but cannot be       |
|       |           |        |       |         | precluded at this   |
|       |           |        |       |         | time.               |
+-------+-----------+--------+-------+---------+---------------------+
|       | B         | Napht  | Not   | Not     | Reserved. A Tier II |
|       | lue-green | halene | avai  | av      | toxicity test with  |
|       | algae     |        | lable | ailable | a blue-green alga   |
|       |           |        |       |         | is recommended if   |
|       |           |        |       |         | testing with        |
|       |           |        |       |         | terrestrial plants  |
|       |           |        |       |         | raises any concerns |
|       |           |        |       |         | and/or if open      |
|       |           |        |       |         | literature data     |
|       |           |        |       |         | with blue-green     |
|       |           |        |       |         | algae are           |
|       |           |        |       |         | unavailable. If     |
|       |           |        |       |         | plants are          |
|       |           |        |       |         | sensitive to        |
|       |           |        |       |         | naphthalene, there  |
|       |           |        |       |         | might be direct     |
|       |           |        |       |         | effects to plants   |
|       |           |        |       |         | and possible        |
|       |           |        |       |         | indirect effect to  |
|       |           |        |       |         | animal taxa due to  |
|       |           |        |       |         | loss of cover or    |
|       |           |        |       |         | food sources.       |
|       |           |        |       |         | However, the        |
|       |           |        |       |         | likelihood for      |
|       |           |        |       |         | plants to be at     |
|       |           |        |       |         | risk from           |
|       |           |        |       |         | naphthalene is low  |
|       |           |        |       |         | but cannot be       |
|       |           |        |       |         | precluded at this   |
|       |           |        |       |         | time.               |
+-------+-----------+--------+-------+---------+---------------------+
| 141-1 | Honey Bee | Napht  | N/A   | N/A     | Naphthalene is      |
|       | Acute     | halene |       |         | volatile. It is     |
|       |           |        |       |         | uncertain if there  |
|       | Contact   |        |       |         | is a direct effect  |
|       | LD~50~    |        |       |         | to pollinators      |
|       |           |        |       |         | visiting flowers    |
|       |           |        |       |         | and gardens treated |
|       |           |        |       |         | with naphthalene or |
|       |           |        |       |         | if there are        |
|       |           |        |       |         | indirect effects to |
|       |           |        |       |         | flowers when bees   |
|       |           |        |       |         | are prevented from  |
|       |           |        |       |         | v                   |
|       |           |        |       |         | isiting/pollinating |
|       |           |        |       |         | the area. An acute  |
|       |           |        |       |         | contact test with   |
|       |           |        |       |         | honeybees is        |
|       |           |        |       |         | recommended.        |
+-------+-----------+--------+-------+---------+---------------------+

**ECOLOGICAL RISK ASSESSMENT**

**Re-Registration**

**Naphthalene**

CAS Registry Number: 91-20-3

U.S. EPA Pesticide Code Number: 055801

> ![](media/image2.png){width="3.1256944444444446in" height="1.34375in"}

Repellent Proposed for Outdoor Uses on Non-Cropped and Domestic Outdoor
Areas

[CAS Name]{.underline}: Naphthalene

[IUPAC Name]{.underline}: Naphthalene

[Proposed End-use Products]{.underline}: "ENOZ® Skat!", "Snake-A-Way",
"Shotgun® Rabbit & Dog Repellent", and "Bat-A-Way Bird, Squirrel, Rabbit
& Bat Repellent" (7.0-99.95% naphthalene as the single active ingredient
in white solid flakes/crystals).

[Assessors]{.underline}:

Stephen Carey, Biologist

Mark Corbin, Senior Environmental Scientist

[Secondary Reviewers]{.underline}:

Pamela Hurley, Toxicologist

James Hetrick, Senior Scientist

[Branch Chief]{.underline}:

Karen Whitby

Ecological Risk Branch III

**Executive** **Summary**

**A. Nature of Chemical Stressor**

The Environmental Fate and Effects Division (EFED) have assessed the
potential ecological risks associated with the use of naphthalene.
Naphthalene is a repellent used to control both indoor and outdoor moth
and mammal infestations. The labeled indoor uses for naphthalene are not
expected to result in exposure to non-target terrestrial and aquatic
organisms. Thus, indoor uses (i.e. mothballs) are not considered in this
assessment. Of the registered uses, four labels currently specify
outdoor use and products are formulated as granular formulations,
technically naphthalene crystals or flakes. The outdoor labels state
that the products are to be used as repellents for snakes, mammals, and
birds from ornamental plants, gardens, and the perimeters of structural
buildings. With the exception of statements that the product should be
applied in bands of at least one inch wide (ENOZ Skat!; EPA Reg \#
1475-146) and up to 12 inches wide (Snake-A-Way; EPA Reg #58630-1), the
outdoor use labels generally contain a non-specific application
description. In addition, the existing labels indicate that multiple
applications may be required for effective repellency, but do not limit
the number of applications.

B.  **Conclusions -- Exposure Characterization**

In order to provide an assessment of potential exposure to non-target
organisms from the terrestrial non-crop use of naphthalene, several
assumptions were made regarding the amount applied per acre and the
total number of applications expected to be used. According to
information provided by the registrants, naphthalene is typically
applied outdoors with application rates of 10.8 lbs/acre for use as a
rabbit and dog repellent and 0.56 lbs/acre as a snake repellent.
Typically, naphthalene is applied in bands of 4 to 12 inches in width,
which will limit the total pounds per acre applied. For the purpose of
this assessment, it is assumed that a single application will represent
a band of 12 inches surrounding a planted bed or the perimeter of a
house/garden. The registrant also indicates that applications should be
repeated as needed with a typical application interval of 2 to 3 months.
Given this, it is assumed, for the purpose of this assessment,
naphthalene will be applied up to six times per year. Since naphthalene
will not be applied to the entire target site but is applied in a band,
an adjustment factor of 4.1% has been applied to GENEEC2 model output to
account for this aspect of the products' applications.

Aquatic exposures were estimated using the Tier 1 model, GENEEC2, and
terrestrial exposures were estimated using the Tier 1 model, T-REX v.
1.3.1. For GENEEC2 and T-REX modelings, granules are used as a surrogate
for flakes or crystals.

**C. Conclusions -- Effects Characterization**

Based on the data requirements for a terrestrial non-crop/domestic
outdoor use as a repellent, all data except terrestrial and aquatic
vascular plants were submitted and reviewed for the naphthalene risk
assessment using the granular banded application and incidental
ingestion exposure methods. Available acute toxicity data with aquatic
species indicate that naphthalene is moderately toxic to freshwater fish
and invertebrates with LC~50~ values of 2.0 and 1.6 mg ai/L,
respectively. Toxicity data with aquatic nonvascular plants indicate
that naphthalene is slightly toxic to green algae with EC~50~ values of
33 and 34 mg/L. Following chronic exposure, a reduction in survival,
feeding behavior, and growth were observed in Coho salmon; the LOAEC and
NOAEC were 0.67 and 0.37 mg ai/L, respectively. The results of an
embryo-larval toxicity test with the Fathead minnow demonstrated adverse
effects at a concentration of 0.85 mg/L, the NOAEC was 0.62 mg/L.[^1]
Toxicity data were not available for aquatic vascular plants;
consequently, the toxicity of naphthalene to aquatic vascular plants is
unknown.

Available acute toxicity data with terrestrial species indicate that
naphthalene is practically non-toxic to upland game birds (acute oral
LD~50~ = 2690 mg ai/kg bw; acute dietary LC~50~ \>5620 mg ai/kg diet).
Acute dietary toxicity data with the mallard duck was not available; the
toxicity to waterfowl exposed to granular naphthalene is unknown.
Available acute toxicity data also indicate that naphthalene is
practically non-toxic to mammals (acute oral LD~50~ = 2649 mg ai/kg bw).

Two-generation reproductive toxicity studies evaluating reproductive
performance of mammals exposed to naphthalene are not available,
although the occurrence of hemolytic anemia in the neonates of anemic,
naphthalene-exposed mothers demonstrates that naphthalene and/or its
metabolites can cross the placental barrier. Following chronic exposure,
rat studies involving naphthalene exposure during gestation reported
that doses of 150 mg/kg/day and greater were maternally toxic to rats
with a decrease in number of live mouse pups per litter with a dose of
300 mg/kg/day given during gestation. *In vitro* studies of naphthalene
embryotoxicity in the presence of liver microsomes support the concept
that naphthalene metabolites may be harmful to the developing
embryo.[^2] Toxicity data were not available for honeybees and
terrestrial plants; consequently, the toxicity of naphthalene to
beneficial insects and terrestrial plants is unknown.

No chronic studies with freshwater and marine/estuarine invertebrates
and birds were available. Summary reviews of available open literature
data concerning the toxicity of naphthalene degradation products were
identified; however, those data were unavailable for this assessment.

**D. Potential Risks to Non-target Animals and Plants**

Based on the available ecotoxicity information and the estimated
environmental exposures, naphthalene may pose an acute risk to birds,
mammals, terrestrial-phase amphibians and reptiles. Acute risk is not
expected for freshwater animals, aquatic-phase amphibians and aquatic
nonvascular plants. Due to lack of toxicity data, risks to honey bees,
and terrestrial and aquatic vascular plants are unknown. Lack of
toxicity data does not preclude potential risk to these taxa. Tables 1
and 2 provide summaries for the environmental risk conclusions for
aquatic and terrestrial animals and plants.

+--------------+-----------------+------------------------------------+
| **TABLE 1.   |                 |                                    |
| Summary of   |                 |                                    |
| E            |                 |                                    |
| nvironmental |                 |                                    |
| Risk         |                 |                                    |
| Conclusions  |                 |                                    |
| for Aquatic  |                 |                                    |
| Organisms**  |                 |                                    |
+==============+=================+====================================+
| **Assessment | **Use Patterns  | **Summarized Risk                  |
| Endpoint**   | with LOC        | Characterization**                 |
|              | Exceedances**   |                                    |
+--------------+-----------------+------------------------------------+
| Acute Risk   | None            | At the peak EECs, there are no     |
| to           |                 | exceedances of the Acute Risk,     |
| Freshwater   |                 | Acute Restricted Use, or Acute     |
| Fish and     |                 | Endangered Species LOCs for        |
| A            |                 | freshwater fish.                   |
| quatic-phase |                 |                                    |
| Amphibians   |                 | EFED currently uses surrogate data |
| from         |                 | (freshwater fish) for              |
| Granular     |                 | aquatic-phase amphibians. Since    |
| Application  |                 | the fish risk assessment indicates |
|              |                 | no acute LOC exceedances,          |
|              |                 | consequently, there are no risk    |
|              |                 | concerns for aquatic-phase         |
|              |                 | amphibians.                        |
+--------------+-----------------+------------------------------------+
| Acute Risk   | None            | At the peak surface water EECs,    |
| to           |                 | there are no exceedances of the    |
| Freshwater   |                 | Acute Risk, Acute Restricted Use,  |
| I            |                 | or Acute Endangered Species LOCs   |
| nvertebrates |                 | for freshwater invertebrates.      |
| from         |                 |                                    |
| Granular     |                 |                                    |
| Application  |                 |                                    |
+--------------+-----------------+------------------------------------+
| Acute Risk   | None            | At the peak surface water EECs,    |
| to           |                 | there are no exceedances of the    |
| Estu         |                 | Acute Risk, Acute Restricted Use,  |
| arine/marine |                 | or Acute Endangered Species LOCs   |
| Fish and     |                 | for estuarine/marine fish and      |
| I            |                 | invertebrates.                     |
| nvertebrates |                 |                                    |
| from         |                 |                                    |
| Granular     |                 |                                    |
| Application  |                 |                                    |
+--------------+-----------------+------------------------------------+
| Risk to      | No information  | No aquatic vascular plant (e.g.,   |
| Aquatic      | available       | duckweed) toxicity studies were    |
| Vascular     |                 | submitted; therefore, risk to      |
| Plants from  |                 | aquatic vascular plants receiving  |
| Granular     |                 | runoff from granular naphthalene   |
| Application  |                 | is unknown. Label and summary      |
|              |                 | reviews of open literature data    |
|              |                 | suggest possible phytotoxicity to  |
|              |                 | plants.                            |
+--------------+-----------------+------------------------------------+
| Risk to      | None            | At the peak surface water EECs,    |
| Aquatic      |                 | there are no exceedances of the    |
| Nonvascular  |                 | Acute Risk or Acute Endangered     |
| Plants from  |                 | Species LOCs for green algae.      |
| Granular     |                 |                                    |
| Application  |                 |                                    |
+--------------+-----------------+------------------------------------+

+--------------+-----------------+------------------------------------+
| **TABLE 2.   |                 |                                    |
| Summary of   |                 |                                    |
| E            |                 |                                    |
| nvironmental |                 |                                    |
| Risk         |                 |                                    |
| Conclusions  |                 |                                    |
| for          |                 |                                    |
| Terrestrial  |                 |                                    |
| Organisms**  |                 |                                    |
+==============+=================+====================================+
| **Risk       | **Use Patterns  | **Summarized Risk                  |
| Conclusion** | with LOC        | Characterization**                 |
|              | Exceedances**   |                                    |
+--------------+-----------------+------------------------------------+
| Acute Risk   | Terrestrial     | Using the LD~50~/ft^2^ exposure    |
| to Birds     | non-crop use    | method for assessing risk from     |
| (including   |                 | granular banded applications,      |
| terre        | (10.8 lbs ai/A  | Acute, Acute Restricted use, and   |
| strial-phase | x 6 appls with  | Endangered Species LOCs are        |
| amphibians   | 60 day          | exceeded for 20, 100, and 1000 g   |
| and          | reapplication   | birds using the dose-based LD~50~  |
| reptiles)    | interval)       | value. Although there is           |
| from         |                 | exceedance of LOCs from the        |
| Granular     | Terrestrial     | LD~50~/ft^2^ analysis, the         |
| Application  | non-crop use    | potential for risk to birds is     |
|              |                 | based on the assumption that birds |
|              | (0.56 lb ai/A x | are feeding exclusively within the |
|              | 6 appls with 60 | 12-inch-wide banded application    |
|              | day             | around the house or garden         |
|              | reapplication   | perimeters. The likelihood for     |
|              | interval)       | risk to birds is low because: 1)   |
|              |                 | It is anticipated that birds may   |
|              |                 | likely be repelled away from the   |
|              |                 | treated band; 2) It is unlikely    |
|              |                 | birds will obtain all dietary      |
|              |                 | items from within the treated      |
|              |                 | band; and, 3) The EECs calculated  |
|              |                 | in the T-REX analysis may be       |
|              |                 | overestimated (e.g., a minimum row |
|              |                 | \[banded\] length of 209 feet long |
|              |                 | around gardens and houses is       |
|              |                 | unlikely).                         |
|              |                 |                                    |
|              |                 | Using the LD~50~/ft^2^ exposure    |
|              |                 | method for assessing risk from     |
|              |                 | granular banded applications, the  |
|              |                 | Acute, Acute Restricted Use and    |
|              |                 | Acute Endangered Species LOCs are  |
|              |                 | exceeded for 20 and 100 g birds    |
|              |                 | using the dose-based LD~50~ value. |
|              |                 | Acute Restricted Use and Acute     |
|              |                 | Endangered Species LOCs are        |
|              |                 | exceeded for 1000 g birds using    |
|              |                 | the dose-based LD~50~ value.       |
|              |                 | Although there is exceedance of    |
|              |                 | LOCs from the LD~50~/ft^2^         |
|              |                 | analysis, the potential for risk   |
|              |                 | to birds is based on the           |
|              |                 | assumption that birds are feeding  |
|              |                 | exclusively within the             |
|              |                 | 12-inch-wide banded application    |
|              |                 | around the perimeter of a house or |
|              |                 | garden. The likelihood for risk to |
|              |                 | birds is low because: 1) It is     |
|              |                 | anticipated that birds may likely  |
|              |                 | be repelled away from the treated  |
|              |                 | band; 2) It is unlikely birds will |
|              |                 | obtain all dietary items from      |
|              |                 | within the treated band; and, 3)   |
|              |                 | The EECs calculated in the T-REX   |
|              |                 | analysis may be overestimated      |
|              |                 | (e.g., a minimum row \[banded\]    |
|              |                 | length of 209 feet long around     |
|              |                 | gardens and houses is unlikely).   |
+--------------+-----------------+------------------------------------+
| Acute Risk   | Terrestrial     | Using the LD~50~/ft^2^ exposure    |
| to Mammals   | non-crop use    | method for assessing risk from     |
| from         |                 | granular applications, the Acute,  |
| Granular     | (both 10.8 and  | Acute Restricted Use and Acute     |
| Application  | 0.56 lb ai/A)   | Endangered Species LOCs are        |
|              |                 | exceeded for 15, 35, and 1000 g    |
|              |                 | mammals ingesting naphthalene      |
|              |                 | granules at both application       |
|              |                 | rates. Although there is           |
|              |                 | exceedance of LOCs from the        |
|              |                 | LD~50~/ft^2^ analysis, the         |
|              |                 | potential for risk to mammals is   |
|              |                 | based on the assumption that       |
|              |                 | mammals are feeding exclusively    |
|              |                 | within the 12-inch-wide banded     |
|              |                 | application around the house or    |
|              |                 | garden perimeters. The likelihood  |
|              |                 | for risk to mammals is low         |
|              |                 | because: 1) It is anticipated that |
|              |                 | mammals will likely be repelled    |
|              |                 | away from the treated band; 2) It  |
|              |                 | is unlikely mammals will obtain    |
|              |                 | all dietary items from within the  |
|              |                 | treated band; and, 3) The EECs     |
|              |                 | calculated in the T-REX analysis   |
|              |                 | is overestimated, since a row      |
|              |                 | (banded) length of 209 feet long   |
|              |                 | around garden and houses is        |
|              |                 | unlikely.                          |
+--------------+-----------------+------------------------------------+
| Risk to      | No information  | No honeybee data were provided;    |
| Non-target   | available       | risk to honeybees visiting treated |
| Beneficial   |                 | areas is unknown. In addition, it  |
| Insects from |                 | is unknown if plants will be       |
| Granular     |                 | indirectly affected from the       |
| Application  |                 | absence of pollinators visiting    |
|              |                 | the area.                          |
+--------------+-----------------+------------------------------------+
| Risk to      | No information  | No terrestrial plant toxicity      |
| Terrestrial  | available       | studies were submitted; risk to    |
| Plants from  |                 | terrestrial plants receiving       |
| Granular     |                 | runoff from granular naphthalene   |
| Application  |                 | is low but cannot be precluded at  |
|              |                 | this time. Labels and a summary    |
|              |                 | review of open literature data     |
|              |                 | suggest possible phytotoxicity to  |
|              |                 | plants.                            |
+--------------+-----------------+------------------------------------+
| Risk to      | Terrestrial     | To exceed the endangered species   |
| Terrestrial  | non-crop use    | LOC, only 1/10^th^ and nine        |
| Animals from |                 | naphthalene granules ingested are  |
| Incidental   | (both 10.8 and  | needed for a 20-g and 1000-g       |
| Ingestion of | 0.56 lbs ai/A x | species, respectively, to pose a   |
| Granules     | 6 appls with 60 | risk from incidental ingestion. To |
|              | day             | exceed the acute restricted use    |
|              | reapplication   | LOC, ½ and 46 naphthalene granules |
|              | interval)       | ingested are needed for a 20-g and |
|              |                 | 1000-g species, respectively, to   |
|              |                 | pose a risk from incidental        |
|              |                 | ingestion. To exceed the acute     |
|              |                 | risk LOC, 1 and 92 naphthalene     |
|              |                 | granules ingested are needed for a |
|              |                 | 20-g and 1000-g species,           |
|              |                 | respectively, to be potentially at |
|              |                 | risk from incidental ingestion.    |
+--------------+-----------------+------------------------------------+

**E. Conclusions -- Endangered Species**

Direct effects LOCs were exceeded for birds, terrestrial-phase
amphibians, reptiles and mammals. Therefore, there is potential for
indirect effects to all terrestrial animal and plant taxa that depend on
those animals as pollinators or seed dispersers, mammal or reptile
burrows for habitat, feeding, or cover requirements, and for survival,
growth, or reproduction. In addition, no terrestrial plant toxicity data
are available; if plants are found to be sensitive to naphthalene, there
might be direct effects to plants and possible indirect effect to animal
taxa due to loss of cover or food sources. The animal and plant species
that reside in those areas, and the basis for the designation, are in
Appendices H and I and are summarized in Table 3, below.

+---------+-----+---------------------+-----+------------------------+
| **Table |     |                     |     |                        |
| 3.      |     |                     |     |                        |
| Listed  |     |                     |     |                        |
| ta      |     |                     |     |                        |
| xonomic |     |                     |     |                        |
| groups  |     |                     |     |                        |
| pote    |     |                     |     |                        |
| ntially |     |                     |     |                        |
| at risk |     |                     |     |                        |
| ass     |     |                     |     |                        |
| ociated |     |                     |     |                        |
| with    |     |                     |     |                        |
| direct  |     |                     |     |                        |
| or      |     |                     |     |                        |
| i       |     |                     |     |                        |
| ndirect |     |                     |     |                        |
| effects |     |                     |     |                        |
| due to  |     |                     |     |                        |
| appli   |     |                     |     |                        |
| cations |     |                     |     |                        |
| of      |     |                     |     |                        |
| naph    |     |                     |     |                        |
| thalene |     |                     |     |                        |
| on      |     |                     |     |                        |
| areas   |     |                     |     |                        |
| where   |     |                     |     |                        |
| orn     |     |                     |     |                        |
| amental |     |                     |     |                        |
| plants, |     |                     |     |                        |
| fl      |     |                     |     |                        |
| owering |     |                     |     |                        |
| beds    |     |                     |     |                        |
| and     |     |                     |     |                        |
| gardens |     |                     |     |                        |
| are     |     |                     |     |                        |
| grown   |     |                     |     |                        |
| natio   |     |                     |     |                        |
| nwide** |     |                     |     |                        |
+---------+-----+---------------------+-----+------------------------+
| *       | **  | **Basis for Direct  | *   | **Basis for Indirect   |
| *Listed | Dir | Effects Concern**   | *In | Effects Concern**      |
| Taxon** | ect |                     | dir |                        |
|         | Eff |                     | ect |                        |
|         | ect |                     | Eff |                        |
|         | s** |                     | ect |                        |
|         |     |                     | s** |                        |
+---------+-----+---------------------+-----+------------------------+
| Terr    | Yes | Since the product   | Yes | Potential concerns for |
| estrial |     | labels state, "Do   |     | monocots and dicots    |
| and     |     | not apply the       |     | that depend on birds,  |
| Semi-   |     | product directly to |     | reptiles,              |
| Aquatic |     | foliage or stems,"  |     | terrestrial-phase      |
| Plants  |     | this statement      |     | amphibians and mammals |
| --      |     | indicates that      |     | as pollinators or seed |
| m       |     | there is a          |     | dispersers. If         |
| onocots |     | possibility of      |     | pollinators such as    |
| and     |     | phytotoxicity. In   |     | honeybees, beneficial  |
| dicots  |     | addition, a summary |     | insects, and           |
|         |     | review of open      |     | birds/mammals are      |
|         |     | literature data     |     | repelled from          |
|         |     | suggests            |     | naphthalene, there     |
|         |     | naphthalene is      |     | might be indirect      |
|         |     | selectively         |     | effects to plants due  |
|         |     | phytotoxic to       |     | to loss of pollinators |
|         |     | plants. However,    |     | for flower             |
|         |     | toxicity data are   |     | fertilization.         |
|         |     | not available for   |     |                        |
|         |     | terrestrial plants  |     |                        |
|         |     | exposed to          |     |                        |
|         |     | naphthalene. If     |     |                        |
|         |     | plants are          |     |                        |
|         |     | sensitive to        |     |                        |
|         |     | naphthalene, there  |     |                        |
|         |     | might be direct     |     |                        |
|         |     | effects to plants.  |     |                        |
|         |     | The likelihood for  |     |                        |
|         |     | plants to be at     |     |                        |
|         |     | risk from           |     |                        |
|         |     | naphthalene is low  |     |                        |
|         |     | but cannot be       |     |                        |
|         |     | precluded at this   |     |                        |
|         |     | time.               |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Ho      | Yes | No data on          | Yes | Potential concerns for |
| neybees |     | honeybees are       |     | honeybees that depend  |
|         |     | available. Since    |     | on mammal or reptile   |
|         |     | naphthalene is      |     | burrows for habitat,   |
|         |     | volatile, it is     |     | feeding, or cover      |
|         |     | uncertain if        |     | requirements.          |
|         |     | honeybees will be   |     |                        |
|         |     | impacted from       |     |                        |
|         |     | pollinating the     |     |                        |
|         |     | treated areas or if |     |                        |
|         |     | flowers will be     |     |                        |
|         |     | indirectly affected |     |                        |
|         |     | from the absence of |     |                        |
|         |     | pollinators. The    |     |                        |
|         |     | likelihood of       |     |                        |
|         |     | direct effects to   |     |                        |
|         |     | honeybees is low    |     |                        |
|         |     | but cannot be       |     |                        |
|         |     | precluded at this   |     |                        |
|         |     | time.               |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Birds   | Yes | The endangered      | Yes | Potential concerns for |
| and     |     | species LOC is      |     | birds and reptiles     |
| Rept    |     | exceeded for both   |     | that eat mammals as a  |
| iles^1^ |     | high and low        |     | food resource.         |
|         |     | application rates.  |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Ter     | Yes | The endangered      | Yes | Potential concerns for |
| restria |     | species LOC is      |     | terrestrial-phase      |
| l-phase |     | exceeded for both   |     | amphibians that eat    |
| Amphib  |     | high and low        |     | birds, reptiles and    |
| ians^1^ |     | application rates.  |     | mammals as a food      |
|         |     |                     |     | source or depend on    |
|         |     |                     |     | mammal or reptile      |
|         |     |                     |     | burrows for habitat    |
|         |     |                     |     | and shelter.           |
+---------+-----+---------------------+-----+------------------------+
| Mammals | Yes | The endangered      | Yes | Potential concerns for |
|         |     | species LOC is      |     | mammals that eat       |
|         |     | exceeded for both   |     | birds, reptiles and    |
|         |     | high and low        |     | terrestrial-phase      |
|         |     | application rates.  |     | amphibians and depend  |
|         |     |                     |     | on reptile burrows for |
|         |     |                     |     | habitat and shelter.   |
+---------+-----+---------------------+-----+------------------------+
| Aquatic | Yes | Since the product   | Yes | Potential concerns for |
| V       |     | labels state, "Do   |     | aquatic vascular       |
| ascular |     | not apply the       |     | plants that depend on  |
| Plants  |     | product directly to |     | birds, reptiles,       |
|         |     | foliage or stems,"  |     | terrestrial-phase      |
|         |     | this statement      |     | amphibians and mammals |
|         |     | indicates that      |     | as pollinators or seed |
|         |     | there is a          |     | dispersers. If         |
|         |     | possibility of      |     | pollinators such as    |
|         |     | phytotoxicity. In   |     | honeybees, beneficial  |
|         |     | addition, a summary |     | insects, and           |
|         |     | review of open      |     | birds/mammals are      |
|         |     | literature data     |     | repelled by            |
|         |     | suggests            |     | naphthalene, there     |
|         |     | naphthalene is      |     | might be indirect      |
|         |     | selectively         |     | effects to plants due  |
|         |     | phytotoxic to       |     | to loss of pollinators |
|         |     | plants. However,    |     | for flower             |
|         |     | toxicity data are   |     | fertilization.         |
|         |     | not available for   |     |                        |
|         |     | aquatic plants      |     |                        |
|         |     | exposed to          |     |                        |
|         |     | naphthalene. If     |     |                        |
|         |     | plants are          |     |                        |
|         |     | sensitive to        |     |                        |
|         |     | naphthalene, there  |     |                        |
|         |     | might be direct     |     |                        |
|         |     | effects to plants.  |     |                        |
|         |     | The likelihood for  |     |                        |
|         |     | plants to be at     |     |                        |
|         |     | risk from           |     |                        |
|         |     | naphthalene is low  |     |                        |
|         |     | but cannot be       |     |                        |
|         |     | precluded at this   |     |                        |
|         |     | time.               |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Fre     | No  | No LOC exceedances  | Yes | If plants are directly |
| shwater |     |                     |     | or indirectly affected |
| Inverte |     |                     |     | from exposure to       |
| brates, |     |                     |     | naphthalene,           |
| Fish    |     |                     |     | freshwater fish and    |
| and     |     |                     |     | amphibians may be      |
| Aquati  |     |                     |     | indirectly affected    |
| c-phase |     |                     |     | due to loss of cover   |
| Amphib  |     |                     |     | or food sources.       |
| ians^2^ |     |                     |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Es      | No  | No LOC exceedances  | Yes | If plants are directly |
| tuarine |     |                     |     | or indirectly affected |
| /marine |     |                     |     | from exposure to       |
| Fish    |     |                     |     | naphthalene,           |
| and     |     |                     |     | estuarine/marine fish  |
| Invert  |     |                     |     | and invertebrates may  |
| ebrates |     |                     |     | be indirectly affected |
|         |     |                     |     | due to loss of cover   |
|         |     |                     |     | or food.               |
+---------+-----+---------------------+-----+------------------------+
| Aquatic | No  | No LOC exceedances  | Yes | Potential concerns for |
| Nonv    |     |                     |     | aquatic nonvascular    |
| ascular |     |                     |     | plants that depend on  |
| Plants  |     |                     |     | birds, reptiles,       |
| --      |     |                     |     | terrestrial-phase      |
| algae   |     |                     |     | amphibians and mammals |
| and     |     |                     |     | as pollinators and     |
| diatoms |     |                     |     | seed dispersers. If    |
|         |     |                     |     | pollinators such as    |
|         |     |                     |     | honeybees, beneficial  |
|         |     |                     |     | insects, and           |
|         |     |                     |     | birds/mammals are      |
|         |     |                     |     | repelled by            |
|         |     |                     |     | naphthalene, there     |
|         |     |                     |     | might be indirect      |
|         |     |                     |     | effects to plants due  |
|         |     |                     |     | to loss of pollinators |
|         |     |                     |     | for flower             |
|         |     |                     |     | fertilization.         |
+---------+-----+---------------------+-----+------------------------+
| 1.      |     |                     |     |                        |
|   Birds |     |                     |     |                        |
|     are |     |                     |     |                        |
|         |     |                     |     |                        |
|    used |     |                     |     |                        |
|     as  |     |                     |     |                        |
|     su  |     |                     |     |                        |
| rrogate |     |                     |     |                        |
|         |     |                     |     |                        |
| species |     |                     |     |                        |
|     for |     |                     |     |                        |
|     ter |     |                     |     |                        |
| restria |     |                     |     |                        |
| l-phase |     |                     |     |                        |
|     amp |     |                     |     |                        |
| hibians |     |                     |     |                        |
|     and |     |                     |     |                        |
|     re  |     |                     |     |                        |
| ptiles; |     |                     |     |                        |
|     the |     |                     |     |                        |
| refore, |     |                     |     |                        |
|     po  |     |                     |     |                        |
| tential |     |                     |     |                        |
|         |     |                     |     |                        |
|  direct |     |                     |     |                        |
|     and |     |                     |     |                        |
|     i   |     |                     |     |                        |
| ndirect |     |                     |     |                        |
|         |     |                     |     |                        |
| effects |     |                     |     |                        |
|     to  |     |                     |     |                        |
|     end |     |                     |     |                        |
| angered |     |                     |     |                        |
|         |     |                     |     |                        |
|  avian, |     |                     |     |                        |
|     ter |     |                     |     |                        |
| restria |     |                     |     |                        |
| l-phase |     |                     |     |                        |
|     amp |     |                     |     |                        |
| hibians |     |                     |     |                        |
|     and |     |                     |     |                        |
|     re  |     |                     |     |                        |
| ptilian |     |                     |     |                        |
|         |     |                     |     |                        |
| species |     |                     |     |                        |
|     are |     |                     |     |                        |
|     con |     |                     |     |                        |
| sidered |     |                     |     |                        |
|         |     |                     |     |                        |
|    equi |     |                     |     |                        |
| valent. |     |                     |     |                        |
|         |     |                     |     |                        |
| 2       |     |                     |     |                        |
| .  Fish |     |                     |     |                        |
|     are |     |                     |     |                        |
|         |     |                     |     |                        |
|    used |     |                     |     |                        |
|     as  |     |                     |     |                        |
|     a   |     |                     |     |                        |
|     su  |     |                     |     |                        |
| rrogate |     |                     |     |                        |
|     for |     |                     |     |                        |
|         |     |                     |     |                        |
| aquatic |     |                     |     |                        |
|         |     |                     |     |                        |
|   phase |     |                     |     |                        |
|         |     |                     |     |                        |
|    amph |     |                     |     |                        |
| ibians; |     |                     |     |                        |
|     the |     |                     |     |                        |
| refore, |     |                     |     |                        |
|     po  |     |                     |     |                        |
| tential |     |                     |     |                        |
|         |     |                     |     |                        |
|  direct |     |                     |     |                        |
|     and |     |                     |     |                        |
|     i   |     |                     |     |                        |
| ndirect |     |                     |     |                        |
|         |     |                     |     |                        |
| effects |     |                     |     |                        |
|     to  |     |                     |     |                        |
|     end |     |                     |     |                        |
| angered |     |                     |     |                        |
|         |     |                     |     |                        |
|    fish |     |                     |     |                        |
|     and |     |                     |     |                        |
|         |     |                     |     |                        |
|  aquati |     |                     |     |                        |
| c-phase |     |                     |     |                        |
|     am  |     |                     |     |                        |
| phibian |     |                     |     |                        |
|         |     |                     |     |                        |
| species |     |                     |     |                        |
|     are |     |                     |     |                        |
|     con |     |                     |     |                        |
| sidered |     |                     |     |                        |
|         |     |                     |     |                        |
|    equi |     |                     |     |                        |
| valent. |     |                     |     |                        |
+---------+-----+---------------------+-----+------------------------+

**F. Identification of Uncertainties and Their Impact on the Risk
Assessment**

There are a number of areas of uncertainty in the terrestrial and
aquatic species risk assessments that could potentially cause an
underestimate or overestimate of risk. First, this assessment accounts
only for exposure to non-target animals and plants to naphthalene, but
not to its degradation products. The risks could be underestimated if
degradates also exhibit toxicity under the conditions of use as stated
on the labels. Summary reviews of available open literature data
concerning the toxicity of naphthalene degradation products were
searched; however, those data were unavailable for this assessment.
Second, the risk assessments only consider the most sensitive species
tested and only considers a subset of possible use scenarios. Third, for
screening terrestrial risk assessments, a generic bird or mammal is
assumed to occupy the treated site, and to consume 100% of its diet as
the pesticide. The actual habitat requirements of any particular
terrestrial species are not considered, and it is assumed that species
occupy, exclusively and permanently, the treated area being modeled.
This assumption leads to a maximum level of exposure in the risk
assessment. Since naphthalene is a repellent used to control unwanted
species from habiting the treated area, the risk estimations for birds,
terrestrial-phase amphibians, reptiles, and mammals exposed to
naphthalene granules may be overestimated. Fourth, the aquatic exposure
assessment relies on GENEEC2 to provide screening level estimates of
exposure using a limited data set of environmental fate data. In
general, GENEEC2 provides high end exposure estimates that likely
over-estimate exposure in aquatic systems. The potential impacts of
uncertainties are detailed in section III.D of this document.

Additional uncertainty results from lack of information and/or data in
several components of this ecological risk assessment, as follows:

\- The T-REX model is designed to calculate risk indices from pesticide
applications on an entire one-acre agricultural field by broadcast
spray/granular application or by rows/bands. Since naphthalene is
proposed for an application of a 12-inch-wide band around the perimeter
of a flowering bed, house, or garden to repel unwanted species, T-REX
assumptions may over-estimate the risk indices for birds,
terrestrial-phase amphibians, reptiles, and mammals exposed to
naphthalene flakes. Even though there is an exceedance of the levels of
concern for acute risk to those species, the exceedance is based on the
assumption that the species occupy, exclusively and permanently, the
12-inch-wide band around the perimeter of a house or garden. To the
extent that a repelled species does not reside exclusively and
permanently within the 12-inch banded area(s), exposure will be less and
risk will presumably be less.

\- No data are available for honeybees to assess the risk to pollinators
visiting flowering beds or gardens. Naphthalene is volatile, and it is
unknown if honeybees will be discouraged from pollinating the treated
area or if plants will be indirectly affected from the absence of
pollinators visiting the area.

\- There are a number of uncertainties associated with the environmental
fate data. No acceptable environmental fate studies have been submitted
to support this risk assessment. A single summary review of available
open literature data was provided for aerobic soil metabolism and
adsorption/desorption. However, these data have not been fully reviewed
and are used as supplemental information for risk assessment purposes.
No additional data for other important environmental fate processes
(hydrolysis, photolysis, aerobic aquatic metabolism) have been
submitted, although some open literature data is available from other
sources (US NPS, 1997) although much of this data is limited and has not
been thoroughly reviewed. Where data are missing, an assumption of
stability has been incorporated into the exposure modeling which likely
over-estimates predicted exposures, particularly aqueous photolysis
which has been shown to be rapid in some studies. In addition,
volatility is unaccounted for in Tier I modeling conducted for this
assessment. It is uncertain whether the aerobic soil metabolism data
includes losses due to volatility (which would be expected in an open
system) and thus it is uncertain whether the lack of accounting for
volatility in the modeling results in an over-estimation of exposure.
There is some suggestion from the open literature that naphthalene
degrades rapidly in aerobic aquatic conditions but these data are
suspect as they may represent lumped dissipation processes and not true
degradation (US NPS, 1997).

\- No terrestrial or aquatic vascular plant studies are available. While
the product labels state specifically for terrestrial non-crop/domestic
outdoor uses, "Do not apply the product directly to foliage or stems,"
this statement indicates that there is a possibility of phytotoxicity;
in addition, a summary review of open literature data suggest that
naphthalene is selectively phytotoxic to plants. If plants are sensitive
to naphthalene, there might be direct affects to plants and possible
indirect affects to animal taxa due to loss of cover or food sources.
The likelihood of risk to plants may be low but cannot be precluded at
this time.

\- No preliminary analysis was performed for non-food uses of
naphthalene because the LOCATES tool does not include county-level
location information for the proposed non-food use of naphthalene.
Consequently, based on the information available at this step in the
assessment process, it is presumed that all listed animal species are
potentially directly affected from the broad range of naphthalene
proposed uses which include areas around houses, cabins, trailers,
garages, utility houses, barns, woodpiles, sand piles, trash cans,
flower beds, plants (ornamentals, roses, spring bulbs), around the
periphery of gardens, and garbage bags placed near residences and other
buildings, streets or alleys for garbage collection. Additional analysis
of listed animal locations, refinement of the action area associated
with naphthalene regulatory decisions, and the biology of the
potentially affected species would be needed before an effects
determination can be made for any of the co-located species identified
by this assessment.

\- Currently, the T-REX model does not have the capability to estimate
chronic exposure to terrestrial animals from banded granular
applications.

**TABLE OF CONTENTS**

I.  **PROBLEM
    FORMULATION.....................\...................................................1**

**A. STRESSOR SOURCE AND
DISTRIBUTION..............................\...............\....1**

**1. Mode of
Action........................................................................................1**

**2. Chemical Identification of
Naphthalene.........................................................1**

**3. Overview of Pesticide
Usage........................................................................2**

**B.
RECEPTORS......................................................................................\...2**

**1. Aquatic
Effects........................................................................................3**

**2. Terrestrial
Effects...........................................................................\.........4**

**3. Ecosystems at
Risk...................................................................................4**

**C. ASSESSMENT
ENDPOINTS............................................................\.........4**

**D. CONCEPTUAL
MODEL\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\......\...5**

**1. Risk
Hypotheses....................................................................................\...6**

**2. Conceptual Model
Diagram\...\...\...\...\...\...\...........................................................6**

**E. ANALYSIS
PLAN................................................\.........................\.........\...8**

**F. DATA
GAPS\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....9**

**II.
ANALYSIS\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....11**

**A. USE
CHARACTERIZATION\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....11**

**B. EXPOSURE
CHARACTERIZATION\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....11**

**1. Environmental Fate and
Transportation\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...11**

**2. Aquatic Exposure
Modeling\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...12**

**3. Terrestrial Exposure
Modeling\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....13**

**C. ECOLOGICAL EFFECTS
CHARACTERIZATION\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....15**

**1. Aquatic
Effects\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...16**

**2. Terrestrial
Effects\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....17**

**III. RISK
CHARACTERIZATION\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....18**

**A. RISKS TO NON-TARGET AQUATIC ORGANISMS AND
PLANTS\...\...\...\...\...\...\...18**

**B. RISKS TO NON-TARGET TERRESTRIAL ANIMALS AND
PLANTS\...\...\...\...\.....19**

**C. RISK
DESCRIPTION\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....21**

**1. Risks to Non-target Aquatic Organisms and
Plants\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...21**

**a. Fish and Aquatic
Invertebrates\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...21**

**b. Aquatic-phase
Amphibians\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....22**

**c. Aquatic
Plants\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....22**

**2. Risks to Non-target Terrestrial Animals and
Plants\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....22**

**a.
Birds\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...23**

**b. Terrestrial-phase Amphibians and
Reptiles\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....25**

**c.
Mammals\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\....26**

**d. Beneficial
Insects\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...26**

**e. Terrestrial
Plants\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...26**

**3. Review of Incident
Data\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...26**

**4. Endocrine
Effect\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...27**

**5. Federally Threatened and Endangered (Listed) Species
Concerns\...\...\...\...\...\...\...\...\.....27**

**a. Action
Area\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...27**

**b. Taxonomic Groups Potentially at
Risk\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...28**

**c. Indirect Effect
Analysis\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....29**

**d. Critical
Habitat\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....30**

**e. Direct Effect Co-occurrence
Analysis\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...30**

**f. Indirect Effect Co-occurrence
Analysis\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...31**

> **D. ASSUMPTIONS, UNCERTAINTIES, STRENGTHS AND LIMITATIONS OF THE
> NAPHTHALENE
> ASSESSMENT\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...33**

**IV. LITERATURE
CITED\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\...\.....37**

**[Appendices]{.underline}**

**Appendix A. Environmental Fate Studies**

**Appendix B. Names and Chemical Structures of Naphthalene and Major
Transformation Products**

**Appendix C. Aquatic Exposure Model and Results (GENEEC2 ver. 2.0)**

**Appendix D. Terrestrial Birds and Mammals Exposure Model and Results
(TREX ver. 1.3.1)**

**Appendix E. Ecological Effects Studies**

**Appendix F. Environmental Fate and Ecotoxicity Bibliography**

**Appendix G. Direct Effects Endangered Species Analysis for Non-Crop
Uses**

**Appendix H. Indirect Effects Endangered Species Analysis for Non-Crop
Uses**

**[Tables]{.underline}**

**Table I-1. Chemical Identification for the Active Ingredient
Naphthalene**

**Table I-2. Overview of Naphthalene Outdoor Uses**

**Table I-3. Taxonomic Groups and Test Species Evaluated for Ecological
Effects in the Screening Level Risk Assessment for Naphthalene.**

**Table I-4. Summary of Assessment and Measurement Endpoints for
Naphthalene as a Non-Food Use**

**Table II-1. Naphthalene Application Information**

**Table II-2. Summary of GENEEC2 Environmental Fate Data Used for
Aquatic Exposure Inputs for Naphthalene**

**Table II-3. Results of GENEEC2 Modeling for Naphthalene Use on
Ornamentals**

**Table II-4. Input Parameters for T-REX Analysis**

**Table II-5. Terrestrial EECs (mg ai/ft^2^) on Avian and Mammalian
Exposed to Granules Following Label-specified Application of Naphthalene
at 10.8 lb ai/A; Determined using the TREX model.**

**Table II-6. Terrestrial EECs (mg ai/ft^2^) on Avian and Mammalian
Exposed to Granules Following Label-specified Application of Naphthalene
at 10.8 lb ai/A; Determined using the TREX model.**

**Table II-7. Toxicity of Naphthalene to Aquatic Organisms and Plants**

**Table II-8. Toxicity of Naphthalene to Terrestrial Animals and
Plants**

**Table III-1.** **Risks to Aquatic Animals and Plants for Naphthalene
Use on Ornamentals; 6 applications, 60 days apart at a rate of 10.8 lbs
a.i./A**

**Table III-2. Granular RQs (LD~50~/ft^2^) from Direct Ingestion of
Flakes at 10.8 lb ai/A - EEC/Toxicity (adjusted mg/ft^2^ / adjusted
LD~50~)**

**Table III-3. Granular RQs (LD~50~/ft^2^) from Direct Ingestion of
Flakes at 10.8 lb ai/A - EEC/Toxicity (adjusted mg/ft^2^ / adjusted
LD~50~)**

**Table III-4. Table III-6. Comparison of Avian Acute Toxicity Values
with Predicted EECs on Granule Consumption**

**Table III-5. Estimates of the Number of Granules, and Minimum Foraged
Area Needed for a 20g, 100g, and 1000g Bird to Achieve the EEC that
would Trigger an Exceedance of the Adjusted LD50, Acute Risk LOC (0.5),
and Endangered Species Risk (0.5) Levels of Concern (LOCs) Based on an
Application Rate of 10.8 lb/A**

**Table III-6. Estimates of the Number of Granules, and Minimum Foraged
Area Needed for a 20g, 100g, and 1000g Bird to Achieve the EEC that
would Trigger an Exceedance of the Adjusted LD50, Acute Risk LOC (0.5),
and Endangered Species Risk (0.5) Levels of Concern (LOCs) Based on an
Application Rate of 0.56 lb/A**

**Table III-7. Probit Dose Response Relationship Analysis**

**Table III-8. Number of Listed Species Located in Non-Food Areas in the
United States of America**

**Table III-9. Listed Taxonomic Groups Potentially at Risk Associated
with Direct or Indirect Effects due to Applications of Naphthalene on
Areas where Ornamental Plants, Flowering Beds and Gardens are Grown
Nationwide.**

**I. PROBLEM FORMULATION**

The purpose of this ecological risk assessment (ERA) is to assist the
Agency in evaluating the actions needed, if any, to address the
ecological risks in terrestrial and aquatic environmental settings
associated with the reregistration of the repellent, the active
ingredient, naphthalene, that is used to repel animals from ornamental
plants, gardens and the perimeters of buildings.

##  **A. Stressor Source and Distribution**

The primary chemical stressor is naphthalene, formulated to repel
snakes, mammals, and birds from ornamental plants, gardens, and the
perimeters of structural buildings. Naphthalene (not to be confused with
[naphtha](http://en.wikipedia.org/wiki/Naphtha)) (also known as
naphthalin, naphthaline, tar camphor, white tar, albocarbon, or
naphthene), is a crystalline,
[aromatic](http://en.wikipedia.org/wiki/Aromaticity), white, solid
[hydrocarbon](http://en.wikipedia.org/wiki/Hydrocarbon), best known as
the primary ingredient of
[mothballs](http://en.wikipedia.org/wiki/Mothball). Naphthalene is
volatile, forming a flammable
[vapor](http://en.wikipedia.org/wiki/Vapor). Its
[molecules](http://en.wikipedia.org/wiki/Molecule) consist of two fused
[benzene](http://en.wikipedia.org/wiki/Benzene) rings. It is
manufactured from [coal tar](http://en.wikipedia.org/wiki/Coal_tar), and
converted to [phthalic
anhydride](http://en.wikipedia.org/wiki/Phthalic_anhydride) for the
manufacture of [plastics](http://en.wikipedia.org/wiki/Plastic),
[dyes](http://en.wikipedia.org/wiki/Dye) and
[solvents](http://en.wikipedia.org/wiki/Solvent). It is also used as an
[antiseptic](http://en.wikipedia.org/wiki/Antiseptic) and
[insecticide](http://en.wikipedia.org/wiki/Insecticide), especially in
mothballs (for indoor uses) and flakes (for outdoor uses). Naphthalene
(C~10~H~8~) is known among polycyclic aromatic hydrocarbon class of
chemicals as a "benzenoid" [polycyclic aromatic
hydrocarbon](http://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbon)
(PAH), an alternant PAH.[^3]^,^[^4]

1.  **Mode of Action**

The toxicological mode of action of naphthalene is poorly understood;
however, published literature indicates that exposure to naphthalene may
induce cataracts, histological changes associated with pneumotoxicity,
glutathione depletion, lipid peroxidation, DNA fragmentation and the
production of the active oxygen species as superoxide anion and hydroxyl
radical. Toxic manifestations of naphthalene are associated with its
oxidative metabolism to various products including quinones,
specifically the naphthoquinone metabolite. The ability to protect
against the toxic effects of naphthalene by using various antioxidants
and free radical scavengers has been demonstrated.[^5]

The repellent mode of action of naphthalene is to keep unwanted animals
away from visiting the areas of interest. It is unclear if it is the
odor of the volatilizing naphthalene that repels the organisms.

2.  **Chemical Identification of Naphthalene**

Table I-1 presents the names and codes used to identify naphthalene in
this assessment.

  ---------------------------------------------- ----------------------------------------------------
  **Table I-1. Chemical Identification for the   
  Active Ingredient Naphthalene.**[^6]           

  **Common Name and Company Code**               Naphthalene

  **USEPA Pesticide Code Number (PC #)**         055801

  **CAS Registry Number**                        91-20-3

  **CAS Name**                                   Naphthalene

  **IUPAC Name**                                 Naphthalene

  **Empirical Formula and Smiles String**        C~10~H~8~

  **Molecular Weight**                           128.18 g/mole

  **Molecular Structure**                        ![](media/image2.png){width="1.2506944444444446in"
                                                 height="0.7916666666666666in"}
  ---------------------------------------------- ----------------------------------------------------

3.  **Overview of Pesticide Usage**

The proposed end-use products for terrestrial non-crop and domestic
outdoor uses are "ENOZ® Skat!", "Snake-A-Way", "Shotgun® Rabbit & Dog
Repellent" and "Bat-A-Way Bird, Squirrel, Rabbit & Bat Repellent" with
naphthalene as the active ingredient in white solid crystals/flakes. The
proposed uses are summarized in Table I-2. The products are labeled as a
repellent for rabbits, rattlesnakes (*Genus crotalus*), checkered garter
(*Thamnophis marcianus*), house mice (*Mus musclus*), Norway rats
(*Rattus norvegicua*), roof rats (*R. rattus*), tree squirrels, bats,
starlings, pigeons, and/or house sparrows from ornamentals, gardens,
planting beds and areas around buildings.

  ----------------- -----------------------------------------------------
  **Table I-2.      
  Overview of       
  Naphthalene       
  Outdoor Uses**    

  **Use grouping**  **Representative Use**

  Terrestrial       Areas around houses, cabins, trailers, garages,
  Non-food +        utility houses, barns, woodpiles, sand piles, trash
  Domestic Outdoor  cans, flower beds, plants (ornamentals, roses, spring
  (residential)     bulbs), around the periphery of gardens, garbage bags
                    placed near residences and other buildings, streets
                    or alleys for garbage collection.
  ----------------- -----------------------------------------------------

The labels state that the products may be applied as bands around the
plants or periphery of gardens and buildings to reduce the frequency of
visits by animals. However, the bandwidth of the bands is dependant on
the product formulation and label statements. The four products
identified above are for terrestrial non-crop or domestic outdoor uses
only, even though there are other naphthalene products for indoor uses.
The proposed application rates range from a maximum of 10.8 lbs/acre to
a minimum of 0.56 lbs/acre for naphthalene uses on terrestrial non-food
or domestic outdoor sites, with up to six applications per year with
60-day reapplication intervals.

B.  **Receptors**

For the screening level risk assessment on naphthalene and its
transformation products, toxicological data generated on representative
test species belonging to broad taxonomic groups are summarized, then
utilized in an assessment of risk for each group. These data are
obtained from registrant-submitted studies and published literature.
Table I-3 lists the taxonomic groups and representative test species
used for evaluation of potential ecological effects on terrestrial
non-food and domestic outdoor uses. Within each of these very broad
taxonomic groups, an acute endpoint is selected from the available
toxicity data for use in risk estimation.

+-------------------------------+--------------------------------------+
| Table I-3. Taxonomic Groups   |                                      |
| and Test Species Evaluated    |                                      |
| for Ecological Effects in the |                                      |
| Screening Level Risk          |                                      |
| Assessment for Naphthalene.   |                                      |
+===============================+======================================+
| **Taxonomic group**           | **Example(s) of representative       |
|                               | species**                            |
+-------------------------------+--------------------------------------+
| Birds, Terrestrial-phase      | Mallard duck (*Anas platyrhynchos*)  |
| Amphibians and Reptiles^a^    |                                      |
|                               | Bobwhite quail (*Colinus             |
|                               | virginianus*)                        |
+-------------------------------+--------------------------------------+
| Mammals                       | Laboratory rat (*Rattus norvegicus*) |
+-------------------------------+--------------------------------------+
| Freshwater fish and           | Bluegill sunfish (*Lepomis           |
| Aquatic-phase Amphibians^b^   | macrochirus*)                        |
|                               |                                      |
|                               | Rainbow trout (*Oncorhynchus         |
|                               | mykiss*)                             |
|                               |                                      |
|                               | Coho salmon (*Oncorhynchus kisutch*) |
+-------------------------------+--------------------------------------+
| Freshwater invertebrates      | Water flea (*Daphnia magna*)         |
+-------------------------------+--------------------------------------+
| Estuarine/marine fish         | Fathead minnow (*Pimephales          |
|                               | promelas*)                           |
+-------------------------------+--------------------------------------+
| Estuarine/marine              | Pacific oyster (*Crassostrea gigas*) |
| invertebrates                 |                                      |
|                               | Grass shrimp (*Palaemonetes pugio*)  |
+-------------------------------+--------------------------------------+
| Terrestrial plants^c^         | Monocots -- No data                  |
|                               |                                      |
|                               | Dicots -- No data                    |
+-------------------------------+--------------------------------------+
| Aquatic vascular plants       | Duckweed -- No data                  |
|                               |                                      |
| Aquatic non-vascular plants   | Green algae (*Chlorella vulgaris*)   |
+-------------------------------+--------------------------------------+
| ^a^Birds are used as          |                                      |
| surrogates for amphibians     |                                      |
| (terrestrial phase) and       |                                      |
| reptiles.                     |                                      |
|                               |                                      |
| ^b^Freshwater fish are used   |                                      |
| as surrogates for amphibians  |                                      |
| (aquatic phase).              |                                      |
|                               |                                      |
| ^c^Four species of two        |                                      |
| families of monocots, of      |                                      |
| which one is corn; six        |                                      |
| species of at least four      |                                      |
| dicot families, of which one  |                                      |
| is soybeans.                  |                                      |
+-------------------------------+--------------------------------------+

No ecological effects data on terrestrial and aquatic vascular plants,
or honeybees are available. The potential risks to terrestrial and
aquatic vascular plants, and honeybees from exposure to naphthalene are
unknown.

A complete discussion of all toxicity data available for this risk
assessment and the resulting measurement endpoints selected for each
taxonomic group are included in the Ecological Effects Characterization
section and Appendix E.

1.  **Aquatic Effects:**

For naphthalene, effects on aquatic organisms are estimated from acute
laboratory studies either submitted to the Agency or found in the open
literature (i.e., ECOTOX). Acute data are available for freshwater fish,
rainbow trout (*Oncorhynchus mykiss*) and bluegill sunfish (*Lepomis
macrochirus*); freshwater invertebrates, water flea (*Daphnia magna*);
estuarine/marine fish, Fathead minnow (*Pimephales promelas*); and
estuarine/marine invertebrates, Pacific oyster (*Crassostrea gigas*) and
Grass shrimp (*Palemonetes pugio*). These freshwater fish species also
act as surrogates for aquatic-phase amphibians. Data is available for
aquatic non vascular plants with one green algae species (*Chlorella
vulgaris*). None is available for aquatic vascular plants.

Data were available to evaluate chronic effects of naphthalene on
aquatic animals are an Early Life-Stage study with Coho salmon
(*Oncorhynchus kisutch*) and Fathead minnow embryo-larval test to
observe the chronic effect to freshwater and marine/estuarine fish.

2.  **Terrestrial Effects:**

The effect of naphthalene on birds is estimated from acute and subacute
studies on the upland game bird, northern bobwhite quail (*Colinus
virginianus*). No studies are available for waterfowl. The bird studies
also act as surrogates for reptiles and terrestrial-phase amphibians.
Effects on mammals are estimated from acute data in rats reviewed by the
Health Effects Division (HED) and effects on mammals from chronic data
in rats from available open literature data.

3.  **Ecosystem at Risk**

The terrestrial ecosystems potentially at risk include the treated area
where the granules are applied in bands. For Tier I assessment purposes,
risk will be assessed to terrestrial animals assumed to exclusively
occur in the treated area directly exposed to naphthalene granules.

The use of naphthalene, as stated in the proposed label, could result in
exposure to aquatic and terrestrial animals inhabiting flowing,
non-flowing or transient freshwater water bodies. For Tier I assessment
purposes, risk will be assessed to aquatic animals assumed to occur in
small, static ponds receiving runoff from adjacent treated areas.

C.  **Assessment Endpoints**

A summary of the assessment and measurement endpoints selected to
characterize potential ecological risks associated with exposure to
naphthalene is provided in Table I-4.

This ecological risk assessment considers the labeled maximum and
minimum application rates, maximum number of applications and minimum
reapplication intervals between applications for representative uses to
estimate exposure concentrations. This assessment is not intended to
represent a site or a time-specified analysis. Instead, this assessment
is intended to represent high-end exposures at a national level.
Likewise, the most sensitive toxicity endpoints are used from surrogate
test species to estimate treatment-related direct effects on acute
mortality/immobilization assessment endpoints. Toxicity tests are
intended to determine effects of outdoor use exposure on birds,
terrestrial-phase amphibians, reptiles, mammals, fish, aquatic-phase
amphibians, aquatic invertebrates, and plants. These tests include
short-term acute and subacute studies and are typically arranged in a
hierarchical or tiered system that progresses from basic laboratory
tests to applied field studies. The toxicity studies are used to
evaluate the potential of a pesticide to cause adverse effects, to
determine whether further testing is required, and to determine the need
for precautionary label statements to minimize the potential adverse
effects to non-target animals and plants (40 CFR 158.202, 2002).

+------------------------------+---------------------------------------+
| **Table I-4. Summary of      |                                       |
| Assessment and Measurement   |                                       |
| Endpoints for Naphthalene as |                                       |
| a Non-Food Use**             |                                       |
+==============================+=======================================+
| **Assessment Endpoint**      | **Measures of Effect**                |
+------------------------------+---------------------------------------+
| 1\. Abundance (i.e.,         | 1a. Bobwhite quail acute oral LD~50~. |
| survival) of birds. Birds    |                                       |
| are surrogate for reptiles   | 1b. Bobwhite quail subacute dietary   |
| and terrestrial phase        | LC~50~.                               |
| amphibians.                  |                                       |
|                              | 1c. Mallard duck subacute dietary     |
|                              | LC~50~.\*                             |
|                              |                                       |
|                              | 1d. Avian reproduction NOAEC\*        |
|                              |                                       |
|                              | \* Currently, no subacute dietary     |
|                              | toxicity study with mallard ducks or  |
|                              | a reproduction study have been        |
|                              | submitted for naphthalene or found in |
|                              | open literature.                      |
+------------------------------+---------------------------------------+
| 2\. Abundance (i.e.,         | 2a. Laboratory rat acute oral LD~50~. |
| survival) of mammals.        |                                       |
+------------------------------+---------------------------------------+
| 3\. Survival and             | 3a. Rainbow trout, bluegill sunfish   |
| reproduction of individuals  | acute LC~50~.                         |
| and communities of           |                                       |
| freshwater fish and          | 3b. Coho salmon chronic (early-life)  |
| invertebrates. Fish are      | NOAEC.                                |
| surrogate for aquatic phase  |                                       |
| amphibians.                  | 3c. Water flea acute EC~50~.          |
+------------------------------+---------------------------------------+
| 4\. Survival and             | 4a. Fathead minnow acute LC~50~.      |
| reproduction of individuals  |                                       |
| and communities of           | 4b. Pacific oyster and Grass shrimp   |
| estuarine/marine fish and    | acute EC~50~.                         |
| invertebrates.               |                                       |
|                              | 4c. Fathead minnow chronic NOAEC.     |
+------------------------------+---------------------------------------+
| 5\. Perpetuation of          | 5a. Monocot and dicot seedling        |
| individuals and populations  | emergence and vegetative vigor        |
| of non-target terrestrial    | endpoints are not available.\*        |
| and semi-aquatic species     |                                       |
| (crops and non-crop plant    | \*Currently, no Tier I terrestrial    |
| species).                    | plants toxicity studies have been     |
|                              | submitted or found in open literature |
|                              | for naphthalene.                      |
+------------------------------+---------------------------------------+
| 6\. Survival of beneficial   | 6a. Honeybee acute contact LD~50~ is  |
| insect populations.          | not available.\*                      |
|                              |                                       |
|                              | \*Currently, no honeybee toxicity     |
|                              | study has been submitted or found in  |
|                              | open literature.                      |
+------------------------------+---------------------------------------+
| 7\. Maintenance and growth   | 7a. Alga EC~50~ and NOAEC values      |
| of individuals and           |                                       |
| populations of aquatic       | 7b. Vascular plant (i.e., duckweed)   |
| plants from standing crop or | EC~50~ and NOAEC values for growth    |
| biomass.                     | rate and biomass measurements are not |
|                              | available.\*                          |
|                              |                                       |
|                              | \*Currently, no Tier I aquatic        |
|                              | vascular plant toxicity studies have  |
|                              | been submitted or found in open       |
|                              | literature.                           |
+------------------------------+---------------------------------------+
| LD~50~ = Lethal dose to 50%  |                                       |
| of the test population.      |                                       |
|                              |                                       |
| NOAEC =                      |                                       |
| No-observed-adverse-effect   |                                       |
| concentration.               |                                       |
|                              |                                       |
| LOAEC =                      |                                       |
| Lo                           |                                       |
| west-observed-adverse-effect |                                       |
| concentration.               |                                       |
|                              |                                       |
| LC~50~ = Lethal              |                                       |
| concentration to 50% of the  |                                       |
| test population.             |                                       |
|                              |                                       |
| EC~50~/EC~25~ = Effect       |                                       |
| concentration to 50/25% of   |                                       |
| the test population.         |                                       |
+------------------------------+---------------------------------------+

D.  **Conceptual Model**

Naphthalene is insoluble and has high potential to volatilize from soil,
so exposure from inhalation is possible. Potentially, soil particulates
containing naphthalene could be transported away from the treatment site
by wind erosion. Naphthalene is not likely to leach to groundwater due
to this use pattern but is expected to be transported via runoff to
surface water bodies. The low Koc would suggest that naphthalene could
leach to groundwater. However, for this assessment groundwater is not
considered as a major route of exposure for aquatic organisms. This
assumption is supported by the fact that in the USGS NAWQA groundwater
data, a total of 6,977 groundwater samples were analyzed for naphthalene
with only 37 positive detections, suggesting that leaching is not likely
significant. Modeling with the SciGrow groundwater model suggests
estimated concentrations are below those estimated for surface water and
below those seen in the USGS NAWQA data. Naphthalene does not
bioaccumulate in aquatic animals. With limited data available for
naphthalene, only potential risks from exposure to parent naphthalene
were quantified. It is uncertain if the transformation products are of
toxicological concern.

The initial emphasis of the risk assessment primarily addresses possible
risks to aquatic vascular and non-vascular plants, fish, aquatic-phase
amphibians and invertebrates and to terrestrial non-target plants,
birds, reptiles, terrestrial-phase amphibians and mammals. Risk was
evaluated for exposure of these organisms to naphthalene through
ingestion of granules and water bodies receiving runoff following
application.

1.  **Risk Hypothesis**

*The use of naphthalene as a repellent in terrestrial non-crop and
domestic outdoor sites will result in either direct or indirect adverse
effects to terrestrial and aquatic animals and plants. Based on the
information, persistence, mode of action, direct toxicity and potential
indirect effects, EFED assumes that naphthalene has the potential to
cause reduced survival, and growth and reproduction impairment to both
terrestrial and aquatic animals and plants as a result of the labeled
uses of the pesticides.*

2.  **Conceptual Model Diagram**

Based on the potential behavior of naphthalene in the environment and
the proposed method of application (e.g., ground granular application),
a conceptual model (Figure ID-1) was developed that represents the
possible relationships between the stressor, ecological endpoints, and
the measurement endpoints. ![](media/image1.wmf)

**E. Analysis Plan**

Naphthalene is registered for use as an insect, invertebrate and mammal
repellent for both indoor and outdoor uses. Naphthalene has a number of
non-pesticidal uses (principally as a constituent of various petroleum
products), which are not considered in this assessment. Indoor
pesticidal uses are principally as mothballs and are not considered
likely to result in exposure to non-target organisms (other than humans)
and are therefore not considered in the ecological risk assessment.
Currently, four registered products included outdoor uses for treatment
of ornamentals, planting beds, and gardens to repel animals. Outdoor
pesticidal uses are principally as flakes or crystals. Information on
application and on the extent of expected outdoor use was provided at
the registrant SMART meeting on March 28, 2007. Based on this
information the exposure assessment will consider two exposure
scenarios. The first is a high use rate at 10.8 lbs/acre with six
applications per year for repelling rabbits and dogs. The second is a
low use rate scenario with an application rate of 0.56 lbs/acre with six
applications per year for repelling snakes. Aquatic exposure estimates
were generated for each scenario using the Tier I exposure model,
GENEEC2, which assumes an area is 100% treated.

Given the limited use of this compound and the fact that it is applied
in a band around ornamentals, planting beds and gardens as a repellent,
an adjustment to the modeled EEC was made. The percent of lot treated
was derived from the United States 2000 Census data
\[http://www.census.gov/main/www/cen2000.html\], which indicated that a
typical lot size is ¼ acre (10,890 square feet) with a typical house
having a footprint of 1000 square feet. If it is assumed that the house
is symmetrical, then the perimeter would be 126.4 ft (31.6 ft on each
side). If it is further assumed that the ornamental beds will be present
in a 10 foot band around the house, then the perimeter would be 206.4
ft. If a typical application band is 1 foot (12 inches), then the
treated area would be 206.4 square feet. If it is additionally assumed
that a garden will typically be present, then an additional calculation
was made to account for the potential treatment to the perimeter of the
garden. In this case, it is assumed that a garden would be 20 feet by
100 feet for a perimeter of 240 feet. An assumption of a one-foot band
of naphthalene around this garden yields a total treated area of 240
square feet. Adding these together and dividing by the total ¼ acre lot
area yields a percent lot treated of 4.1%. The resultant GENEEC2 has
been adjusted by this factor.

Ecological risk will be assessed to determine the potential for acute
effects (*i.e.,* lethality) to mammals, birds, fish or invertebrates
using screening-level risk assessment models. Risk will be assessed on
the treated site for birds and mammals and in an adjacent pond for
freshwater fish and invertebrates. Ecotoxicity data on sublethal
(*e.g.,* reproductive, growth) effects were not available, so chronic
risk is not addressed in this assessment.

Risk to aquatic animals will be assessed using GENEEC2, a Tier 1 model
that estimates concentrations in a 1-hectare, 2-meter-deep water body
adjacent to the 10-hectare treated site that drains into the water body.
Since granular applications are assumed, this water body is also assumed
to receive no drift from the treated site.

Terrestrial exposures from granular applications (mg ai/square foot)[^7]
for birds, terrestrial-phase amphibians, reptiles and mammals will be
estimated using the Tier 1 model, T-REX Version 1.3.1 (T-REX, 2007). In
addition, a banded granular application assumes that 100% of the
granules are unincorporated on the ground. Risk to terrestrial animals
from exposure to granules will be based on LD~50~/ft^2^ values. The
LD~50~/ft^2^ values are calculated using a toxicity value (adjusted
LD~50~ of the assessed animal and its weight classes) and the EEC (mg
ai/ft^2^) and are directly compared with Agency's levels of concern
(LOCs). Since naphthalene is used only for granular applications,
exposures to animals from foraging on food items with naphthalene
residues (short and tall grass, broadleaves, seeds) are not estimated in
this assessment. Details of the TREX model and EEC/RQ calculations are
presented in Appendix D.

**F. Data Gaps**

For environmental fate there are no acceptable fate studies. However, a
single supplemental study has been provided which summarizes open
literature data on adsorption/desorption and aerobic soil metabolism
data. Other fate parameters needed to conduct this assessment have
either been extrapolated from the open literature data (aerobic aquatic
metabolism half life) or conservatively assumed to be stable (photolysis
and hydrolysis). The lack of these data provides uncertainty to this
assessment (Table I-5). Elimination of this uncertainty would require
submission of additional data for these fate processes.

  ---------------------------------------------------------------------------
  **Table I-5.                     
  Environmental                    
  Fate Data                        
  Requirements                     
  for                              
  Naphthalene**                    
  --------------- ---------------- ------------------------------------------
  **Guideline     **Data Gap**     **Value of Additional Testing**
  \#**                             

  162-1           Aerobic Soil     **Low**. Supplemental data from open
                  Metabolism       literature. Model assumptions were based
                                   on these supplemental data. Submission of
                                   acceptable data can provide for
                                   confirmation of assumptions or inputs for
                                   refined modeling.

  163-1           Adsorption       **Low**. Supplemental data from open
                  Desorption       literature. Model assumptions were based
                                   on these supplemental data. Submission of
                                   acceptable data can provide for
                                   confirmation of assumptions or inputs for
                                   refined modeling.

  162-4           Aerobic Aquatic  **Medium**. Lack of date led to assumption
                  Metabolism       of half life at two times the aerobic soil
                                   metabolism value. Submission of data can
                                   remove uncertainty in this assumption.
  ---------------------------------------------------------------------------

Several ecotoxicity data gaps for naphthalene were also identified
during problem formulation (Table I-6).

+-------+-------------------+-----------------------------------------+
| **    |                   |                                         |
| Table |                   |                                         |
| I-6.  |                   |                                         |
| Ecolo |                   |                                         |
| gical |                   |                                         |
| Tox   |                   |                                         |
| icity |                   |                                         |
| Data  |                   |                                         |
| Re    |                   |                                         |
| quire |                   |                                         |
| ments |                   |                                         |
| for   |                   |                                         |
| Nap   |                   |                                         |
| hthal |                   |                                         |
| ene** |                   |                                         |
+=======+===================+=========================================+
| *     | **Data Gap**      | **Value of Additional Testing**         |
| *Guid |                   |                                         |
| eline |                   |                                         |
| \#**  |                   |                                         |
+-------+-------------------+-----------------------------------------+
| 71-2  | Avian subacute    | **High** -- No study with mallard duck  |
|       | dietary LC~50~    | is available. Study is required to      |
|       |                   | evaluate the toxicity to waterfowl. In  |
|       | (mallard duck)    | the dietary study with upland game bird |
|       |                   | (bobwhite quail), body weight decreased |
|       |                   | while feed consumption increased when   |
|       |                   | compared to controls.                   |
+-------+-------------------+-----------------------------------------+
| 122-1 | Tier I Nontarget  | **Low to Medium** -- No studies are     |
|       | Terrestrial Plant | available. Since the product labels     |
|       | Phytotoxicity:    | state specifically for terrestrial      |
|       | Seedling          | non-crop/domestic outdoor uses, "Do not |
|       | emergence and     | apply the product directly to foliage   |
|       | Vegetative vigor  | or stems," this statement indicates     |
|       |                   | that there is a possibility of          |
|       |                   | phytotoxicity; in addition, summary     |
|       |                   | reviews of open literature data         |
|       |                   | indicate naphthalene is phytotoxic to   |
|       |                   | plants. If plants are sensitive to      |
|       |                   | naphthalene, there might be direct      |
|       |                   | effects to plants and possible indirect |
|       |                   | effects to animal taxa due to loss of   |
|       |                   | cover or food sources. The likelihood   |
|       |                   | for risks to plants is low but cannot   |
|       |                   | be precluded at this time.              |
+-------+-------------------+-----------------------------------------+
| 122-2 | Tier I Nontarget  | **Low to Medium** - No studies are      |
|       | Aquatic Plant     | available. Since the product labels     |
|       | Growth            | state specifically for terrestrial      |
|       |                   | non-crop/domestic outdoor uses, "Do not |
|       |                   | apply the product directly to foliage   |
|       |                   | or stems," this statement indicates     |
|       |                   | that there is a possibility of          |
|       |                   | phytotoxicity; in addition, summary     |
|       |                   | reviews of open literature data         |
|       |                   | indicate naphthalene is phytotoxic to   |
|       |                   | plants. If plants are sensitive to      |
|       |                   | naphthalene, there might be direct      |
|       |                   | effects to plants and possible indirect |
|       |                   | effects to animal taxa due to loss of   |
|       |                   | cover or food sources. The likelihood   |
|       |                   | for risks to plants is low but cannot   |
|       |                   | be precluded at this time.              |
+-------+-------------------+-----------------------------------------+
| 141-1 | Acute honey bee   | **Low** -- No study is available. It is |
|       | contact LD~50~    | uncertain how pollinators will react to |
|       |                   | naphthalene when actively visiting      |
|       |                   | gardens and flowers where naphthalene   |
|       |                   | is applied frequently. Also, since      |
|       |                   | naphthalene is volatile, it is          |
|       |                   | uncertain how naphthalene fumes will    |
|       |                   | impact honeybees. If honeybees are      |
|       |                   | sensitive to naphthalene, there might   |
|       |                   | be indirect effects to plants due to    |
|       |                   | loss of pollinators. The likelihood for |
|       |                   | risks to honeybees is low but cannot be |
|       |                   | precluded at this time.                 |
+-------+-------------------+-----------------------------------------+

### **II. ANALYSIS** 

### 

### **Use Characterization**

Information provided by the registrant indicates that a significant
proportion of naphthalene use is on ornamentals, planting beds, and
gardens. Generally, naphthalene is applied for outdoor use as flakes in
bands surrounding the site to be protected. Typically, these bands do
not exceed 12 inches in width and are replenished as needed (typically,
every two to three months). The use patterns assessed in the exposure
assessment are summarized in Table II-1.

+----------------+-----------+---------+----------+--------+---------+
| **Table II-1   |           |         |          |        |         |
| Naphthalene    |           |         |          |        |         |
| Application    |           |         |          |        |         |
| Information    |           |         |          |        |         |
| ^A^**          |           |         |          |        |         |
+================+===========+=========+==========+========+=========+
| **Crop**       | **Form    | *       | *        | **M    | **      |
|                | ulation** | *Method | *Maximum | aximum | Minimum |
|                |           | of      | App      | Se     | Appl    |
|                |           | Applic  | lication | asonal | ication |
|                |           | ation** | Rate**   | Rate** | Int     |
|                |           |         |          |        | erval** |
|                |           |         | **(lbs   |        |         |
|                |           |         | /acre)** |        |         |
+----------------+-----------+---------+----------+--------+---------+
| Ornamentals    | Granules  | Ground  | 10.8     | 64.8   | 2       |
| for rabbit &   |           |         |          |        | months  |
| dog repellent  |           |         |          |        |         |
+----------------+-----------+---------+----------+--------+---------+
| Ornamentals    | Granules  | Ground  | 0.56     | 3.36   | 2       |
| for snake      |           |         |          |        | months  |
| repellent      |           |         |          |        |         |
+----------------+-----------+---------+----------+--------+---------+

^A^ Based on information provided at SMART Meeting on March 28, 2007

### **B. Exposure Characterization**

### 

### **1. Environmental Fate and Transport** 

Several environmental fate studies (aerobic soil and aqueous photolysis)
were submitted but deemed to be unacceptable for risk assessment
purposes due to poor material balances, inadequate sample intervals, and
issues with volatile trapping and therefore have not been used in this
assessment. A single overview of open literature data (MRID 45346801)
provided supplemental data on the adsorption/desorption and aerobic soil
metabolism properties of naphthalene. Possible degradation processes
affecting naphthalene (and PAH's in general) include photo-oxidation and
microbial degradation.

For sorption a total of 13 open literature studies were submitted and
summarized and indicated that the solubility of naphthalene ranged from
30 to 31.7 mg/L and that the Koc ranged from 200 to 1470 for a variety
of soils from North America, Europe and China. The study author
concluded from this review that naphthalene was bound relatively rapidly
to soils with a sustained desorption over days to weeks. For
biodegradation a total of 15 open literature studies were submitted and
reviewed and found that naphthalene degraded with aerobic soil
metabolism half-lives between 3.5 and 40 days with no appreciable
degradation under anaerobic conditions. Possible dissipation processes
affecting naphthalene (and PAH's in general) include volatilization,
bioaccumulation, adsorption, and leaching.

Additional open literature data (US NPS, 1997, US HHS, 2005) describes
both aerobic soil degradation and adsorption values that are consistent
with values described above, although under certain conditions
degradation from soil may be somewhat longer. In addition, these data
suggest that naphthalene degrades rapidly by aqueous photolysis. The
data (US HHS, 2005) also suggest that under certain conditions
naphthalene dissipates rapidly from open water systems although it is
unclear whether the dissipation observed was due to degradation or
lumped dissipation processes including transport out of the systems by
flowing water. The additional data suggest that up to 30% of loss from
soil can occur due to volatilization and also suggest that once in air,
naphthalene should degrade rapidly (US NPS, 1997). Once in air,
naphthalene tends to dissipate rapidly (US HHS, 2005). Finally, these
data suggest that naphthalene is relatively stable under anaerobic
conditions (US NPS, 1997).

A number of transformation products were identified in the various open
literature studies. The study author proposed a degradation pathway for
naphthalene, which ultimately resulted in catechol. Transitional
transformation products included
cis-1,2-dihydroxy-1,2-dihydronapthalene, 1,2-dihydroxy-napthalene,
2-hydroxchromene-2-carboxylate (HCCA),
trans-o-hydroxy-benzylidenpyruvate (tHBPA), salicyladehyde, and
salicylate. There are no registrant submitted environmental fate data on
these degradation products that would allow for an approximation of
environmental fate inputs, the available open literature data is sparse,
and there is no available toxicity data for these compounds. Therefore,
these degradates have not been quantitatively assessed in the exposure
assessment.

A copy of the submitted summary along with the metabolic pathway,
transformation product structures, results from individual studies, and
bibliography of open literature data is presented in Appendix G.

**2. Aquatic Exposure Modeling**

EFED normally relies on an integrated approach for conducting exposure
assessments that relies on an analysis of both monitoring data and
modeling. In the case of naphthalene, no monitoring data are available.
Therefore, this assessment relies solely on modeling.

EFED uses a tiered system of pesticide exposure modeling to assess risk
of a pesticide to the environment. Each of the tiers is designed to
screen out pesticides by requiring higher, more complex levels of
investigation only for those that have not passed the next lower tier.
In this case, EFED has conducted a Tier I aquatic exposure assessment
relying on GENEEC2. GENEEC (*GEN*eric *E*stimated *E*nvironmental
*C*oncentration, version 2) is a program to calculate acute as well as
longer-term estimated environmental concentration (EEC) values. It
considers reduction in dissolved pesticide concentration due to
adsorption of pesticide to soil or sediment, incorporation, degradation
in soil before washoff to a water body, direct deposition of spray drift
into the water body, and degradation of the pesticide within the water
body[^8].

Number range CHAPTERNumber range CHAPTERThe appropriate GENEEC2 input
parameters were selected from the environmental fate data submitted by
the registrant and in accordance with US EPA-OPP EFED water model
parameter selection guidelines, Guidance for Selecting Input Parameters
in Modeling the Environmental Fate and Transport of Pesticides, Version
2.3, February 28, 2002. These parameters are summarized in **Table
II-2**. Results of GENEEC2 modeling are presented in **Table II-3** and
Appendix C**.**

  ------------------------------------------------------------------------
  **Table II-2 Summary of                            
  GENEEC2 environmental                              
  fate data used for                                 
  aquatic exposure inputs                            
  for naphthalene**                                  
  ------------------------- ------------------------ ---------------------
  **Fate Property**         **Value**                **MRID (or source)**

  Solubility in Water       32 mg/L                  Product Chemistry

  Photolysis in Water       stable                   Assumed

  Aerobic Soil Metabolism   32.6 days (90^th^ % of 9 MRID 45346801
  Half-lives                values)                  

  Hydrolysis                stable                   Assumed

  Aerobic Aquatic           65.2 days                Twice the aerobic
  Metabolism (water column)                          soil metabolism rate
                                                     constant

  Koc                       131 (lowest non-sand     MRID 45346801
                            Koc)                     

  Application Efficiency    99 % for ground\*        default value

  Spray Drift Fraction      1 % for ground           default value
  ------------------------------------------------------------------------

\* -- Although not specified on labels it is assumed that only ground
applications would be used.

Two scenarios were modeled to represent a high naphthalene use scenario
and at low use scenarios. The high use scenario was modeled at 10.8
lbs/acre with six applications per year, while the low use scenario was
modeled at 0.56 lbs/acre with six applications per year. The application
method was modeled as ground application with a granular formulation.
The results of the Tier I modeling is summarized in Table II-3.

+---------+-----------+------------+------+------+------+------+------+
| **Table |           |            |      |      |      |      |      |
| II-3    |           |            |      |      |      |      |      |
| Results |           |            |      |      |      |      |      |
| of      |           |            |      |      |      |      |      |
| GENEEC2 |           |            |      |      |      |      |      |
| M       |           |            |      |      |      |      |      |
| odeling |           |            |      |      |      |      |      |
| for     |           |            |      |      |      |      |      |
| Naph    |           |            |      |      |      |      |      |
| thalene |           |            |      |      |      |      |      |
| Use on  |           |            |      |      |      |      |      |
| O       |           |            |      |      |      |      |      |
| rnament |           |            |      |      |      |      |      |
| als\*** |           |            |      |      |      |      |      |
+=========+===========+============+======+======+======+======+======+
| **Use   | **Ap      | **Number   | **   | **4  | **21 | **60 | **90 |
| Site**  | plication | of         | Peak | day  | day  | -day | -day |
|         | Rate      | Appl       | EEC  | EEC  | EEC  | EEC  | EEC  |
|         | (lb       | ications** | (pp  | (pp  | (pp  | (pp  | (pp  |
|         | s/acre)** |            | b)** | b)** | b)** | b)** | b)** |
|         |           | **(i       |      |      |      |      |      |
|         |           | nterval)** |      |      |      |      |      |
+---------+-----------+------------+------+------+------+------+------+
| Orna    | 10.8      | 6          | 26.9 | 26.6 | 25.2 | 22.4 | 20.5 |
| mentals |           |            |      |      |      |      |      |
| for     |           | (2 months) |      |      |      |      |      |
| rabbit  |           |            |      |      |      |      |      |
| & dog   |           |            |      |      |      |      |      |
| re      |           |            |      |      |      |      |      |
| pellent |           |            |      |      |      |      |      |
+---------+-----------+------------+------+------+------+------+------+
| Orna    | 0.56      | 6          | 1.4  | 1.4  | 1.3  | 1.2  | 1.1  |
| mentals |           |            |      |      |      |      |      |
| for     |           | (2 months) |      |      |      |      |      |
| snake   |           |            |      |      |      |      |      |
| re      |           |            |      |      |      |      |      |
| pellent |           |            |      |      |      |      |      |
+---------+-----------+------------+------+------+------+------+------+

\* Note these EECs are adjusted by 4.1% to account for the fact that the
product is only applied in a band around ornamental, planting beds, and
gardens

Unaccounted for in this exposure assessment is the fact that naphthalene
is volatile. No product chemistry data were available but an estimate of
the vapor pressure was made using EpiSuite. EpiSuite reported an
experimentally derived value for vapor pressure of 8.5 x10^-2^ mm Hg
(which is consistent with the registrant reported value of 10.5 Pa, or
7.8 x 10^-2^ mm Hg) suggesting that naphthalene is volatile. Given the
volatility of this compound and the fact that the Tier I model used to
estimate exposure does not account for volatility as a route of
dissipation it is likely that the exposure estimates derived above are
over-predictions of potential exposure. However, it is unknown from the
open literature data used in this assessment whether the systems were
closed or flow-through. If the aerobic metabolism data (and hence the
half-life used in this assessment) were flow-through, then the
degradation reported would include volatilization as a process. The
impact of volatility on this assessment is uncertain.

Given the mobile nature of this compound, it is possible that
naphthalene may leach to groundwater. A cursory review of USGS NAWQA
groundwater data indicates that of 6,977 samples only 37 detections of
naphthalene were found. While the maximum concentration detected was 70
ppb, there are a number of possible sources of naphthalene contamination
of groundwater, including many with significantly higher use (e.g.,
industrial, jet fuel). Thus it appears that leaching is not likely a
significant route of exposure for the pesticidal use of naphthalene. A
quick check of groundwater leaching potential using SciGrow yields an
estimated concentration in groundwater of 16.3 ppb at the highest
application rate (10.8 lbs/acre x 6 applications) and 0.84 ppb at the
lowest rate (0.56 lbs/acre x 6 applications). These values are below the
surface water concentrations predicted by GENEEC2, are lower than the
NAWQA values described above, and assume a much broader area of
application than anticipated for this use pattern (bands surrounding
gardens and planting beds). Given the lines of evidence described, it is
expected that as an exposure route for ecological risk assessment
,naphthalene in groundwater resulting from pesticidal use is minimal.

**3. Terrestrial Exposure Modeling**

Naphthalene when applied outdoors is formulated as a granular
formulation, technically as flakes or crystals. For T-REX modeling,
granules are used as a surrogate for flakes or crystals.

Terrestrial exposures for naphthalene are estimated using the conceptual
approach given in the Tier-1 model, T-REX Version 1.3.1[^9]. A default
foliar half-life of 35 days was assumed. The LD~50~/ft^2^ is used to
estimate risk for granular formulations through row and banded
applications. Number range CHAPTERNumber range CHAPTERThe appropriate
T-REX input parameters were selected from the product labels. For the
method of application using granules (flakes), one row length of 209 ft
with row spacing of 2,500 inches, 1-foot bandwidth and 0% incorporation
was assumed. For minimum foraging area estimates need to exceed the
levels of concerns, a maximum mass of 38 mg naphthalene per flake is
used.[^10] These parameters are summarized in **Table II-4**.

+---------+----------+----------+-------------------+----------------+
| **Table |          |          |                   |                |
| II-4.   |          |          |                   |                |
| Input   |          |          |                   |                |
| Par     |          |          |                   |                |
| ameters |          |          |                   |                |
| for     |          |          |                   |                |
| T-REX   |          |          |                   |                |
| Ana     |          |          |                   |                |
| lysis** |          |          |                   |                |
+=========+==========+==========+===================+================+
| **Appl  | **Formu  | *        | **Guidance**      | **Comments**   |
| ication | lation** | *Input** |                   |                |
| Type**  |          |          |                   |                |
+---------+----------+----------+-------------------+----------------+
| Ro      | Granular | No. of   | Row spacing is    | Only one row   |
| ws/Band |          | Row,     | the amount of     | was assumed. A |
|         |          | Length,  | space (inches)    | minimum row    |
|         |          | and      | between crop rows | length of 209  |
|         |          | Spacing  | and is obtained   | foot with row  |
|         |          |          | from the product  | spacing of     |
|         |          |          | label.            | 2,500 inches   |
|         |          |          |                   | was used       |
|         |          |          |                   | assuming       |
|         |          |          |                   | application    |
|         |          |          |                   | occurs on one  |
|         |          |          |                   | side of an     |
|         |          |          |                   | one-acre       |
|         |          |          |                   | field.         |
+---------+----------+----------+-------------------+----------------+
|         |          | Band     | Bandwidth is the  | A foot         |
|         |          | width    | width of the      | bandwidth was  |
|         |          |          | applied pesticide | obtained from  |
|         |          |          | row (inches) and  | labels.        |
|         |          |          | is obtained from  |                |
|         |          |          | the product       |                |
|         |          |          | label.            |                |
+---------+----------+----------+-------------------+----------------+
|         |          | \%       | Value depends on  | 0%             |
|         |          | inco     | the method of     | incorporated   |
|         |          | rporated | application:      | was obtained   |
|         |          |          |                   | from labels.   |
|         |          |          | T-Banded --       |                |
|         |          |          | covered with      |                |
|         |          |          | specified amount  |                |
|         |          |          | of soil: 99%      |                |
|         |          |          | In-furrow, drill, |                |
|         |          |          | or shanked-in:    |                |
|         |          |          | 99%               |                |
|         |          |          |                   |                |
|         |          |          | Side-dress,       |                |
|         |          |          | banded, mix, or   |                |
|         |          |          | lightly           |                |
|         |          |          | incorporate with  |                |
|         |          |          | soil: 85%         |                |
|         |          |          |                   |                |
|         |          |          | Broadcast, mix,   |                |
|         |          |          | or lightly        |                |
|         |          |          | incorporated: 85% |                |
|         |          |          |                   |                |
|         |          |          | Side-dress,       |                |
|         |          |          | banded,           |                |
|         |          |          | unincorporated:   |                |
|         |          |          | 0%                |                |
|         |          |          |                   |                |
|         |          |          | Broadcast, aerial |                |
|         |          |          | broadcast,        |                |
|         |          |          | unincorporated:   |                |
|         |          |          | 0%                |                |
+---------+----------+----------+-------------------+----------------+
|         |          | Weight   | Data is obtained  | 38 mg (from    |
|         |          | of       | from registrant.  | SMART meeting) |
|         |          | granule  |                   |                |
+---------+----------+----------+-------------------+----------------+

The T-REX model does not allow for multiple applications at different
rates so the terrestrial exposures for this risk assessment were
estimated assuming six ground applications at 10.8 lbs/acre with a
reapplication interval of 60 days. A second lower use rate scenario was
modeled assuming six ground applications at 0.56 lbs/acre. Results of
T-REX modeling are presented in Tables II-5 and II-6.

  ----------------------------------------------- -----------------------
  **Table II-5 Terrestrial EECs (mg ai/ft^2^) on  
  avian and mammalian ingesting granules          
  following label-specified application of        
  naphthalene at 10.8 lb ai/A; determined using   
  the TREX model**                                

  **Intermediate Calculations**                   

  \# rows acre-1:                                 1.00

  row length (ft):                                208.71

  lb ai/1000 ft row:                              51.65

  bandwidth (ft):                                 1.00

  mg ai/ft^2^ (EEC):                              23429.24

  exposed EEC (mg ai/ft^2^):                      23429.24
  ----------------------------------------------- -----------------------

  -----------------------------------------------------------------------
  **Table II-6 Terrestrial EECs (mg ai/ft^2^) on  
  avian and mammalian ingesting granules          
  following label-specified application of        
  naphthalene at 0.56 lb ai/A; determined using   
  the TREX model**                                
  ----------------------------------------------- -----------------------
  **Intermediate Calculations**                   

  \# rows acre-1:                                 1.00

  row length (ft):                                208.71

  lb ai/1000 ft row:                              51.65

  bandwidth (ft):                                 1.00

  mg ai/ft^2^ (EEC):                              1214.85

  exposed EEC (mg ai/ft^2^):                      1214.85
  -----------------------------------------------------------------------

**C. Ecological Effects Characterization**

Summaries of the available ecotoxicity studies can be found in
**Appendix E.**

Following implementation of the Overview document (USEPA, 2004a), EFED
has begun incorporating data from open literature into ecological risk
assessments (USEPA, 2004b). Toxicity data from open literature are
identified via the ECOTOX search engine and maintained by EPA/ORD. Open
literature data presented in this risk assessment were obtained from the
data provided to EFED by ORD on 11/6/2006. In order to be included in
the ECOTOX database, papers must meet the following minimum criteria:

1\. the toxic effects are related to a single chemical exposure;

2\. the toxic effects are on an aquatic or terrestrial plant or animal
species;

3\. there is a biological effect on live, whole organisms;

4\. a concurrent environmental chemical concentration/dose or
application rate is reported; and

5\. there is an explicit duration of exposure

Data that passes the ECOTOX screen is evaluated along with the
registrant-submitted data, and may be incorporated qualitatively or
quantitatively into the risk assessment. In general, effects data in the
open literature that are less than or more conservative than the
registrant-submitted data are considered. The degree to which open
literature data is quantitatively or qualitatively characterized is
dependent on whether the information is relevant to the assessment
endpoints (i.e., maintenance of survival, reproduction, and growth)
identified in the problem formulation. For example, endpoints such as
behavior modifications are likely to be qualitatively evaluated, because
it is unclear whether such modifications cause a reduction in species
survival, reproduction, and/or growth. Specific open literature data
that are considered include the following:

1\. the endpoint is more sensitive than those identified in the
registrant data;

2\. the data is for under represented taxa (i.e., amphibians); and

3\. the data includes endpoints not normally evaluated in registrant
studies, but ecologically relevant

An examination of the studies found in the open literature (ECOTOX) did
not provide any lower endpoints than the studies submitted by the
Registrant; however, several open literature studies with other taxa
groups were available for this assessment. Acute studies with the
Fathead minnow, Pacific oyster, and Grass shrimp were available to
observe the effect of naphthalene to estuarine/marine fish and
invertebrates. A Freshwater Fish Early Life-Stage study with Coho salmon
and embryo-larval test with fathead minnow were available to observe the
effect to fish from long-term exposure. For toxicity effects to aquatic
plants, several green algae studies were available. Studies with soil
invertebrates were available to observe the effect to terrestrial
invertebrates. A summarized table of toxicity endpoints selected for
aquatic and terrestrial risk assessment can be found in Tables II-7 and
II-8, respectively.

> **1. Aquatic Effects**

With the exception of the Pacific oyster, available freshwater and
estuarine/marine fish and invertebrate acute toxicity data suggest that
naphthalene is moderately toxic to aquatic animals (Table II-7). Chronic
freshwater fish reproduction data indicates that survival and growth
were affected; the NOAEC was determined to be 0.37 mg/L. For
estuarine/marine fish, a chronic embryo-larval test indicates adverse
effects at 0.85 mg/L; the NOAEC was determined to be 0.62 mg/L. Aquatic
plant growth studies with green algae were less sensitive than animals
with concentrations of 33 and 34 mg/L, which categorizes naphthalene as
slight toxic to green alga. No toxicity study with aquatic vascular
plants is available for this ecological risk assessment.

+--------+-------------------+-------------+------+-------+---------+
| *      |                   |             |      |       |         |
| *Table |                   |             |      |       |         |
| II-7.  |                   |             |      |       |         |
| To     |                   |             |      |       |         |
| xicity |                   |             |      |       |         |
| of     |                   |             |      |       |         |
| Napht  |                   |             |      |       |         |
| halene |                   |             |      |       |         |
| to     |                   |             |      |       |         |
| A      |                   |             |      |       |         |
| quatic |                   |             |      |       |         |
| Org    |                   |             |      |       |         |
| anisms |                   |             |      |       |         |
| and    |                   |             |      |       |         |
| Pl     |                   |             |      |       |         |
| ants** |                   |             |      |       |         |
+========+===================+=============+======+=======+=========+
| **T    | **Test Organism** | *           | **V  | **E   | *       |
| axon** |                   | *Endpoint** | alue | cotox | *MRID** |
|        |                   |             | \*** | icity |         |
|        |                   |             |      | Categ | **Cl    |
|        |                   |             | *    | ory** | assific |
|        |                   |             | *(mg |       | ation** |
|        |                   |             | a    |       |         |
|        |                   |             | .i./ |       |         |
|        |                   |             | L)** |       |         |
+--------+-------------------+-------------+------+-------+---------+
| Fres   | Rainbow trout     | 96-hr       | **2  | moder | 4       |
| hwater |                   | LC~50~      | .0** | ately | 5030801 |
| Fish   | *Onchorhynchus    |             |      | toxic |         |
|        | mykiss*           | NOAEC       | 0.86 |       | suppl   |
|        |                   | (mortality) |      |       | emental |
|        |                   |             | 0.86 |       |         |
|        |                   | NOAEC       |      |       |         |
|        |                   | (sublethal) |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
|        | Bluegill sunfish  | 96-hr       | 3.2  | moder | 4       |
|        |                   | LC~50~      |      | ately | 4302701 |
|        | *Lepomis          |             | 1.4  | toxic |         |
|        | macrochirus*      | NOAEC       |      |       | acc     |
|        |                   | (mortality) | 1.4  |       | eptable |
|        |                   |             |      |       |         |
|        |                   | NOAEC       |      |       |         |
|        |                   | (sublethal) |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
|        | Coho salmon       | 40D NOAEC   | **0. | None  | 127330  |
|        |                   |             | 37** |       |         |
|        | *Oncorhynchus     | 40D LOAEC   |      |       | suppl   |
|        | kisutch*          |             | 0.67 |       | emental |
+--------+-------------------+-------------+------+-------+---------+
| Fres   | Water flea        | 48-hr       | **1  | moder | 4       |
| hwater |                   | EC~50~      | .6** | ately | 4302702 |
| Invert | *Daphnia magna*   |             |      | toxic |         |
| ebrate |                   | NOAEC       | 0.48 |       | acc     |
|        |                   | (mortality) |      |       | eptable |
|        |                   |             | \    |       |         |
|        |                   | NOAEC       | >8.8 |       |         |
|        |                   | (sublethal) |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
| Estu   | Fathead minnow    | 96-hr       | **6  | moder | De      |
| arine/ |                   | LC~50~      | .6** | ately | Graeve, |
|        | *Pimephales       |             |      | toxic | et al.  |
| marine | promelas*         | NOAEC       | NR   |       | 1980    |
|        |                   | (mortality) |      |       |         |
| Fish   |                   |             | NR   |       |         |
|        |                   | NOAEC       |      |       |         |
|        |                   | (sublethal) |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
|        |                   | Chronic     | **0. | None  | De      |
|        |                   | NOAEC       | 62** |       | Graeve, |
|        |                   |             |      |       | et al.  |
|        |                   | Chronic     | NR   |       | 1980    |
|        |                   | LOAEC       |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
| Est    | Pacific oyster    | 96-hr       | **1  | p     | LeGore, |
| uarine |                   | EC~50~      | 99** | racti | 1974    |
| /      | *Crassostrea      |             |      | cally |         |
|        | gigas*            | NOAEC       | NR   | non   |         |
| marine |                   | (mortality) |      | toxic |         |
|        |                   |             | NR   |       |         |
| I      |                   | NOAEC       |      |       |         |
| nverte |                   | (sublethal) |      |       |         |
| brates |                   |             |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
|        | Grass shrimp      | 96-hr       | **2. | moder | Tatem,  |
|        |                   | LC~50~      | 35** | ately | 1976    |
|        | *Palaemonetes     |             |      | toxic |         |
|        | pugio*            | NOAEC       | NR   |       |         |
|        |                   | (mortality) |      |       |         |
|        |                   |             | NR   |       |         |
|        |                   | NOAEC       |      |       |         |
|        |                   | (sublethal) |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
| Va     | Duckweed          | 7-day EC50  | No   | No    | No data |
| scular |                   |             | data | data  |         |
| Plant  | *Lemna gibba*     | NOAEC       |      |       |         |
+--------+-------------------+-------------+------+-------+---------+
| Non-va | Green algae       | 48-hr       | **   | sli   | Kauss & |
| scular |                   | EC~50~      | 33** | ghtly | Hutc    |
| Plant  | *Chlorella        |             |      | toxic | hinson, |
|        | vulgaris*         | NOAEC LOAEC | NR   |       | 1975    |
|        |                   |             |      |       |         |
|        |                   |             | NR   |       |         |
+--------+-------------------+-------------+------+-------+---------+

\***Bolded** values indicate toxicity thresholds used to calculate risk
quotients.

NR -- not reported

Available avian acute toxicity data suggest that naphthalene is
practically non-toxic to upland game bird species both on acute oral and
dietary basis (**Table II-8**). No subacute dietary study with the
mallard duck was available; consequently, it is unknown how toxic
naphthalene is to waterfowl species. Naphthalene is practically
non-toxic to mammals on an acute oral basis.

**2. Terrestrial Effects**

+--------+------------+---------+------+---------+--------+----------+
| *      |            |         |      |         |        |          |
| *Table |            |         |      |         |        |          |
| II-8** |            |         |      |         |        |          |
| **To   |            |         |      |         |        |          |
| xicity |            |         |      |         |        |          |
| of     |            |         |      |         |        |          |
| Napht  |            |         |      |         |        |          |
| halene |            |         |      |         |        |          |
| to     |            |         |      |         |        |          |
| Terre  |            |         |      |         |        |          |
| strial |            |         |      |         |        |          |
| A      |            |         |      |         |        |          |
| nimals |            |         |      |         |        |          |
| and    |            |         |      |         |        |          |
| Pl     |            |         |      |         |        |          |
| ants** |            |         |      |         |        |          |
+========+============+=========+======+=========+========+==========+
| **T    | **Test     | **Test  | **En | **Val   | *      | **MRID   |
| axon** | Organism** | Type**  | dpoi | ue^a^** | *Ecoto | Classifi |
|        |            |         | nt** |         | xicity | cation** |
|        |            |         |      |         | Cate   |          |
|        |            |         |      |         | gory** |          |
+--------+------------+---------+------+---------+--------+----------+
| Bird   | Bobwhite   | Acute   | LD   | **2690  | pract  | 148176   |
|        | quail      | Oral    | ~50~ | mg/kg   | ically |          |
|        |            |         |      | bw**    | no     | ac       |
|        | *Colinus   |         |      |         | ntoxic | ceptable |
|        | vi         |         |      |         |        |          |
|        | rginianus* |         |      |         |        |          |
+--------+------------+---------+------+---------+--------+----------+
|        |            | S       | LC   | *       | pract  | 148175   |
|        |            | ubacute | ~50~ | *\>5620 | ically |          |
|        |            | Dietary |      | mg/kg   | no     | ac       |
|        |            |         |      | diet**  | ntoxic | ceptable |
+--------+------------+---------+------+---------+--------+----------+
|        | Mallard    | S       | LC   | No data | Not    | Not      |
|        | duck       | ubacute | ~50~ |         | ava    | a        |
|        |            | Dietary |      |         | ilable | vailable |
|        | *Anas      |         |      |         |        |          |
|        | plat       |         |      |         |        |          |
|        | yrhynchos* |         |      |         |        |          |
+--------+------------+---------+------+---------+--------+----------+
| Mammal | Rat        | Acute   | LD   | **2649  | pract  | 148174   |
|        |            | Oral    | ~50~ | mg/kg   | ically |          |
|        | *Rattus    |         |      | bw**    | no     |          |
|        | n          |         |      |         | ntoxic |          |
|        | orvegicus* |         |      |         |        |          |
+--------+------------+---------+------+---------+--------+----------+
| Bene   | Honey bee  | Acute   | LD   | No data | Not    | Not      |
| ficial |            | Contact | ~50~ |         | ava    | a        |
| i      | *Apis      |         |      |         | ilable | vailable |
| nsects | mellifera* |         |      |         |        |          |
+--------+------------+---------+------+---------+--------+----------+
| Soil   | *Folsomia  | Chronic | N    | **88    | None   | S.T.J.   |
| I      | candida*   | Effects | OAEC | µmol/kg |        | Droge et |
| nverte |            | on Soil |      | soil**  |        | al       |
| brates |            | Invert  | L    |         |        |          |
|        |            | ebrates | OAEC | 409     |        |          |
|        |            | (repro  |      | µmol/kg |        |          |
|        |            | duction |      | soil    |        |          |
|        |            | and     |      |         |        |          |
|        |            | su      |      |         |        |          |
|        |            | rvival) |      |         |        |          |
+--------+------------+---------+------+---------+--------+----------+
|        | *          |         | N    | 220     | None   | S.T.J.   |
|        | Enchytaeus |         | OAEC | µmol/kg |        | Droge et |
|        | crypticus* |         |      | soil    |        | al       |
|        |            |         | L    |         |        |          |
|        |            |         | OAEC | 2045    |        |          |
|        |            |         |      | µmol/kg |        |          |
|        |            |         |      | soil    |        |          |
+--------+------------+---------+------+---------+--------+----------+
| Terre  | Monocots   | S       | EC   | No data | Not    | Not      |
| strial | and dicots | eedling | ~25~ |         | ava    | a        |
| plants |            | em      |      |         | ilable | vailable |
|        |            | ergence | N    |         |        |          |
|        |            | and     | OAEC |         |        |          |
|        |            | Veg     |      |         |        |          |
|        |            | etative | L    |         |        |          |
|        |            | vigor   | OAEC |         |        |          |
+--------+------------+---------+------+---------+--------+----------+

**^a^ Bolded** values indicate toxicity thresholds used to calculate
risk quotients.

No terrestrial plant seedling emergence or vegetative vigor studies are
available for this ecological risk assessment. However, the labels state
specifically, "Do not apply the product directly to foliage or stems."
This statement indicates that there is a possibility of phytotoxicity
and open literature data suggest naphthalene is selectively phytotoxic
to plants (Spencer, E. Y. Guide to the Chemicals Used in Crop
Protection, 7^th^ edition, publication 1093). Until terrestrial plant
studies are available, it is uncertain which plant species is
selectively affected when exposed to naphthalene. In addition, no
beneficial insect studies are available; it is uncertain how pollinators
will react to naphthalene when visiting ornamental flowers and gardens.

**III. RISK CHARACTERIZATION**

Risk characterization integrates EECs and toxicity estimates and
evaluates the likelihood of adverse ecological effects to non-target
species. In a deterministic approach, an exposure estimate is divided by
a single point estimate of toxicity to calculate a risk index (RQ or
LD~50~/ft^2^). The RQ (for aquatic animals) or LD~50~/ft^2^ (for
terrestrial animals) is then compared to Agency's levels of concern
(LOCs) that serve as criteria for categorizing potential risk to
non-target species.

**A. Risks to Non-target Aquatic Organisms and Plants**

Based on the available ecotoxicity information and the modeled aquatic
exposures (from the GENEEC2 model), it appears that naphthalene poses
minimal acute risk to aquatic animals and aquatic nonvascular plants
(*i.e.*, fish, aquatic-phase amphibians, invertebrates, and alga) when
used at six applications, 60 days apart, at a rate of 10.8 lbs/acre
(**Table III-1**). Therefore, minimal acute risk also is expected from
minimum use rate of 0.56 lbs/acre for freshwater animals, because EECs
resulting from the lower use rate scenario to those aquatic species are
lower than the maximum use rate scenario. Risks to aquatic vascular
plants are also unknown due to lack of ecotoxicity data.

+-----------+-----------+--------------------+--------+-----+---------+
| **Table   |           |                    |        |     |         |
| III-1.**  |           |                    |        |     |         |
| **Risks   |           |                    |        |     |         |
| to        |           |                    |        |     |         |
| Aquatic   |           |                    |        |     |         |
| Animals   |           |                    |        |     |         |
| and       |           |                    |        |     |         |
| Plants    |           |                    |        |     |         |
| for       |           |                    |        |     |         |
| Na        |           |                    |        |     |         |
| phthalene |           |                    |        |     |         |
| Use on    |           |                    |        |     |         |
| Ornam     |           |                    |        |     |         |
| entals;** |           |                    |        |     |         |
|           |           |                    |        |     |         |
| **6       |           |                    |        |     |         |
| appl      |           |                    |        |     |         |
| ications, |           |                    |        |     |         |
| 60 days   |           |                    |        |     |         |
| apart at  |           |                    |        |     |         |
| a rate of |           |                    |        |     |         |
| 10.8 lbs  |           |                    |        |     |         |
| a.i./A**  |           |                    |        |     |         |
+===========+===========+====================+========+=====+=========+
| **Taxon** | **        | **Toxicity         | **EEC  | **R | **LOCs  |
|           | Species** | Endpoint**         | (****µ | Q^1 | Exceed  |
|           |           |                    | g/L)** | ^** | ed^2^** |
+-----------+-----------+--------------------+--------+-----+---------+
| F         | Rainbow   | 96-hr LC~50~ = 2.0 | 26.9   | 0.  | None    |
| reshwater | trout     | mg/L               | (peak) | 013 |         |
| Fish      |           |                    |        |     |         |
|           | *Onch     | (or 2000 µg/L)     |        |     |         |
|           | orhynchus |                    |        |     |         |
|           | mykiss*   |                    |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
|           | Coho      | 40-day NOAEC =     | 22.4   | 0   | None    |
|           | salmon    | 0.37 mg/L          | (60D)  | .06 |         |
|           |           |                    |        |     |         |
|           | *Onc      | (or 370 µg/L)      |        |     |         |
|           | orhynchus |                    |        |     |         |
|           | kisutch*  |                    |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
| F         | Water     | 48-hr LC~50~ = 1.6 | 26.9   | 0.  | None    |
| reshwater | flea      | mg/L               | (peak) | 017 |         |
| Inv       | *Daphnia  |                    |        |     |         |
| ertebrate | magna*    | (or 1600 µg/L)     |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
| Marine/   | Fathead   | LC~50~ = 6.6 mg/L  | 26.9   | \<0 | None    |
| estuarine | minnow    |                    | (peak) | .01 |         |
| Fish      |           | (or 6600 µg/L)     |        |     |         |
|           | *P        |                    |        |     |         |
|           | imephales |                    |        |     |         |
|           | promelas* |                    |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
|           |           | NOAEC = 0.62 mg/L  | 22.4   | 0   | None    |
|           |           |                    | (60D)  | .04 |         |
|           |           | (or 620 µg/L)      |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
| Marine/   | Grass     | LC~50~ = 2.35 mg/L | 26.9   | 0   | None    |
| estuarine | shrimp    |                    | (peak) | .01 |         |
| Inv       |           | (or 2350 µg/L)     |        |     |         |
| ertebrate | *Pal      |                    |        |     |         |
|           | aemonetes |                    |        |     |         |
|           | pugio*    |                    |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
| Vascular  | Duckweed  | No data            | 26.9   | Not |         |
| Plant     |           |                    | (peak) | ava |         |
|           | *Lemna    |                    |        | ila |         |
|           | gibba*    |                    |        | ble |         |
+-----------+-----------+--------------------+--------+-----+---------+
| F         | Green     | EC~50~ = 33 mg/L   | 26.9   | \<0 | None    |
| reshwater | Algae     |                    | (peak) | .01 |         |
| Non       | *         | (or 33000 µg/L)    |        |     |         |
| -Vascular | Chlorella |                    |        |     |         |
| Plant     | vulgaris* |                    |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+
| ^1^ Acute |           |                    |        |     |         |
| Risk      |           |                    |        |     |         |
| Quotients |           |                    |        |     |         |
| are       |           |                    |        |     |         |
| c         |           |                    |        |     |         |
| alculated |           |                    |        |     |         |
| using the |           |                    |        |     |         |
| following |           |                    |        |     |         |
| formula:  |           |                    |        |     |         |
| EE        |           |                    |        |     |         |
| C/LC~50~; |           |                    |        |     |         |
| Chronic   |           |                    |        |     |         |
| Risk      |           |                    |        |     |         |
| Quotients |           |                    |        |     |         |
| are       |           |                    |        |     |         |
| c         |           |                    |        |     |         |
| alculated |           |                    |        |     |         |
| using     |           |                    |        |     |         |
| E         |           |                    |        |     |         |
| EC/NOAEC. |           |                    |        |     |         |
|           |           |                    |        |     |         |
| ^2^ Acute |           |                    |        |     |         |
| LOC for   |           |                    |        |     |         |
| aquatic   |           |                    |        |     |         |
| animals   |           |                    |        |     |         |
| \>0.05    |           |                    |        |     |         |
| for       |           |                    |        |     |         |
| e         |           |                    |        |     |         |
| ndangered |           |                    |        |     |         |
| species,  |           |                    |        |     |         |
| \>0.1 for |           |                    |        |     |         |
| r         |           |                    |        |     |         |
| estricted |           |                    |        |     |         |
| use and   |           |                    |        |     |         |
| \>0.5 for |           |                    |        |     |         |
| n         |           |                    |        |     |         |
| on-listed |           |                    |        |     |         |
| species;  |           |                    |        |     |         |
| LOC for   |           |                    |        |     |         |
| aquatic   |           |                    |        |     |         |
| plants    |           |                    |        |     |         |
| \>1;      |           |                    |        |     |         |
| Chronic   |           |                    |        |     |         |
| LOC for   |           |                    |        |     |         |
| aquatic   |           |                    |        |     |         |
| animals   |           |                    |        |     |         |
| \>1.      |           |                    |        |     |         |
+-----------+-----------+--------------------+--------+-----+---------+

**B. Risks to Non-target Terrestrial Animals and Plants**

*Birds, reptiles and terrestrial-phase amphibians*

Based on the available terrestrial ecotoxicity information and the
predicted direct ingestion exposures (from the T-REX model); naphthalene
appears to pose acute risk to birds, terrestrial-phase amphibians and
reptiles. For granular uses at the maximum application rate of 10.8
lbs/acre (Table III-2), the T-REX model indicates that the acute risk,
restricted use and endangered species LOCs are exceeded for all bird
weight classes. At 0.56 lbs/acre, only the restricted use and endangered
species LOCs are exceeded for the 1000-g bird weight class exposed to
naphthalene granules; all LOCs are exceeded for the 20- and 100-gram
weight classes. A definitive acute dietary LC~50~ was not established
for the bobwhite quail (*i.e.*, LC~50~ \> 5620 mg/kg-diet), and the TREX
model only allow dose-based RQs for granular applications; thus, acute
dietary risk quotients were not calculated and excluded from assessment
at this time.

*Mammals*

The acute LD~50~/ft^2^s to terrestrial mammals, as a result of the
assessed uses of naphthalene at 10.8 (Table III-2) and 0.56 lbs/acre
(Table III-3), exceed the LOCs for acute risk, restricted use and
endangered species.

+---------------------------+------------------+-----------+-----------+
| **Table III-2 Granular    |                  |           |           |
| LD~50~/ft^2^ (RQs) from   |                  |           |           |
| Direct Ingestion of       |                  |           |           |
| Flakes at 10.8 lb ai/A    |                  |           |           |
| -**                       |                  |           |           |
|                           |                  |           |           |
| **EEC/Toxicity (adjusted  |                  |           |           |
| mg/ft^2^ / adjusted       |                  |           |           |
| LD~50~)^A^**              |                  |           |           |
+===========================+==================+===========+===========+
| **Taxa**                  | **Weight Class** |           | **LOCs    |
|                           |                  |           | E         |
|                           |                  | **LD~50   | xceeded** |
|                           |                  | ~/ft^2^** | ^B^       |
+---------------------------+------------------+-----------+-----------+
| Avian                     | 20 g             | **6       | Acute     |
|                           |                  | 04.48\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 100 g            | **        | Acute     |
|                           |                  | 94.97\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 1000 g           | *         | Acute     |
|                           |                  | *6.72\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
| Mammal                    | 15 g             | **2       | Acute     |
|                           |                  | 68.18\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 35 g             | **1       | Acute     |
|                           |                  | 42.05\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 1000 g           | **        | Acute     |
|                           |                  | 11.49\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
| ^A^ Bird LD~50~ = 2690    |                  |           |           |
| mg/kg, Mammal LD~50~ =    |                  |           |           |
| 2649 mg/kg; mg/ft^2^ =    |                  |           |           |
| 23429.24                  |                  |           |           |
|                           |                  |           |           |
| \* Exceed acute risk,     |                  |           |           |
| restricted use, and       |                  |           |           |
| endangered species LOCs   |                  |           |           |
| of 0.5, 0.2 and 0.1,      |                  |           |           |
| respectively.             |                  |           |           |
|                           |                  |           |           |
| ^B^ Acute LOC for         |                  |           |           |
| terrestrial animals:      |                  |           |           |
| \>0.1 for endangered      |                  |           |           |
| species, \>0.2 for        |                  |           |           |
| restricted use and \>0.5  |                  |           |           |
| for acute risk            |                  |           |           |
+---------------------------+------------------+-----------+-----------+

+---------------------------+------------------+-----------+-----------+
| **Table III-3 Granular    |                  |           |           |
| RQs (LD~50~/ft^2^) from   |                  |           |           |
| Direct Ingestion of       |                  |           |           |
| Flakes at 0.56 lb ai/A    |                  |           |           |
| -**                       |                  |           |           |
|                           |                  |           |           |
| **EEC/Toxicity (adjusted  |                  |           |           |
| mg/ft^2^ / adjusted       |                  |           |           |
| LD~50~)^A^**              |                  |           |           |
+===========================+==================+===========+===========+
| **Taxa**                  | **Weight Class** |           | **LOCs    |
|                           |                  |           | E         |
|                           |                  | **LD~50   | xceeded** |
|                           |                  | ~/ft^2^** | ^B^       |
+---------------------------+------------------+-----------+-----------+
| Avian                     | 20 g             | **        | Acute     |
|                           |                  | 31.34\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 100 g            | *         | Acute     |
|                           |                  | *4.92\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 1000 g           | *         | R         |
|                           |                  | *0.35\^** | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
| Mammal                    | 15 g             | **        | Acute     |
|                           |                  | 13.91\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 35 g             | *         | Acute     |
|                           |                  | *7.37\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
|                           | 1000 g           | *         | Acute     |
|                           |                  | *0.60\*** | Risk,     |
|                           |                  |           | R         |
|                           |                  |           | estricted |
|                           |                  |           | Use,      |
|                           |                  |           | E         |
|                           |                  |           | ndangered |
|                           |                  |           | Species   |
+---------------------------+------------------+-----------+-----------+
| ^A^ LD~50~ = 2690 mg/kg,  |                  |           |           |
| Mammal LD~50~ = 2649      |                  |           |           |
| mg/kg; mg/ft^2^ = 1214.85 |                  |           |           |
|                           |                  |           |           |
| \* Exceed acute risk,     |                  |           |           |
| restricted use, and       |                  |           |           |
| endangered species LOCs   |                  |           |           |
| of 0.5, 0.2 and 0.1,      |                  |           |           |
| respectively.             |                  |           |           |
|                           |                  |           |           |
| \^ Exceed acute           |                  |           |           |
| restricted use and        |                  |           |           |
| endangered species LOCs   |                  |           |           |
| of 0.2 and 0.1,           |                  |           |           |
| respectively.             |                  |           |           |
|                           |                  |           |           |
| ^B^ Acute LOC for         |                  |           |           |
| terrestrial animals:      |                  |           |           |
| \>0.1 for endangered      |                  |           |           |
| species, \>0.2 for        |                  |           |           |
| restricted use and \>0.5  |                  |           |           |
| for acute risk            |                  |           |           |
+---------------------------+------------------+-----------+-----------+

*Beneficial insects*

No honeybee toxicity studies are available; consequently, it is
uncertain if honeybees will be impacted when pollinating in the treated
area.

*Terrestrial plants*

No seedling emergence or vegetative vigor studies are available;
consequently, it is uncertain if terrestrial plants will be affected in
the treated area.

C.  **Risk Description**

    1.  **Risks to Non-target Aquatic Organisms and Plants**

        In the conceptual model, surface runoff/erosion to adjacent
        bodies of water was predicted as the most likely sources of
        exposure of naphthalene to non-target aquatic animals and
        plants. Risks to aquatic organisms (i.e. fish, invertebrates,
        and plants) were assessed based on modeled estimated
        environmental concentrations (EECs) and available toxicity data.
        Aquatic EECs for the ecological exposure to naphthalene were
        estimated using GENEEC2 employing the standard ecological water
        body (Table II-2) and a percent area treated of 4.1% (Section
        1.E).

        The risk hypothesis stated that the use of naphthalene has the
        potential to cause adverse effects to aquatic animals and
        plants. For direct acute risk to freshwater and estuarine/marine
        animals and algae and direct risk following chronic exposure to
        freshwater and estuarine/marine fish, this assessment refutes
        this hypothesis. Risk of direct effects to aquatic animals and
        algae are below the Agency's LOC, but risk is unknown for
        aquatic vascular plants. Therefore, potential risk of indirect
        effects cannot be precluded for aquatic animals and plants until
        data on aquatic vascular plants are provided.

**a. Fish and Aquatic Invertebrates**

Available acute toxicity data for aquatic species indicate that
naphthalene is moderately toxic to freshwater and estuarine/marine fish
and invertebrates. A comparison of the GENEEC peak EEC of naphthalene in
surface water of 26.9 µg/L to toxicity values for fish and invertebrates
indicates that the toxicity values (between 1600 - 6600 µg ai/L) were 59
to 245-fold higher than the highest estimated EEC. Therefore, it is
concluded that the acute risk to freshwater and estuarine/marine animals
is expected to be minimal.

The chronic risk quotients calculated (freshwater and estuarine/marine
fish) is less than the chronic LOC of 1.0 for the proposed uses. For
outdoor uses, the GENEEC2 60-day EEC was 22.4 µg/L. The NOAECs from
chronic toxicity studies with the freshwater and marine/estuarine fish
were 0.37 mg/L (370 µg/L) and 0.62 mg/L (620 µg/L). A comparison of the
EEC with the NOAECs resulted in risk quotients that are several orders
of magnitude below the LOC of 1.0. Therefore, potential risk to fish
following chronic exposure is lower than the chronic level of concern
for aquatic animals.

Consequently, the risks for acute and chronic adverse effects related to
reproduction, growth, and survival are lower than the Agency's concern
level for freshwater and estuarine/marine fish and invertebrates
inhabiting surface waters adjacent to naphthalene treated site.
Nevertheless, freshwater animals are as sensitive as estuarine/marine
animals to naphthalene.

**b. Aquatic-phase Amphibians**

EFED currently uses surrogate data (fish) to estimate potential risks to
non-target aquatic phase amphibians. Risks to fish species were
discussed above. No aquatic-phase amphibian toxicity data was submitted
or was located in the open literature. Therefore, based on conclusions
for fish, risk to aquatic phase amphibians is also expected to be lower
than the Agency's concern level.

**c. Aquatic Plants**

EFED currently uses aquatic plant data to estimate potential risks to
non-target aquatic plants from surface water runoff. Available open
literature toxicity data with green algae indicate naphthalene is
slightly toxic to aquatic nonvascular plants with EC~50~ values of 33
and 34 mg/L. No aquatic vascular plant toxicity data with duckweed was
submitted or located in the open literature. Therefore, it is uncertain
if aquatic vascular plants inhabiting surface waters adjacent to a
treated area would be at risk for adverse effects to growth and
development as a result of naphthalene outdoor uses. In addition to the
uncertainty, the proposed labels state that the products should not be
applied directly to foliage or stems. This statement and summary reviews
of open literature data indicate that there is a possibility of
phytotoxicity to plants.

**2. Risks to Non-target Terrestrial Animals and Plants**

In the conceptual model, animals exposed to naphthalene granules as
surrogate for flakes or crystals and wind erosion of soil particles are
the most likely sources of naphthalene exposure to non-target
terrestrial animals and plants. While terrestrial organisms may also be
exposed by other routes, such as incidental ingestion of contaminated
soil, dermal contact with treated granular surfaces and soil during
activities in the treated areas, and preening activities, the primary
route of exposure to naphthalene granules in this assessment will be via
the oral route.

Acute risks to terrestrial animals (i.e. birds, terrestrial-phase
amphibians, reptiles and mammals) and plants (i.e. dicots and monocots)
were assessed based on modeled EECs and available toxicity data. As part
of the terrestrial assessment, exposure concentrations of naphthalene
granules to non-target terrestrial animals were modeled according to
labeled maximum and minimum application rates. For terrestrial birds,
terrestrial-phase amphibians, reptiles and mammals, estimates of upper
bound levels of naphthalene granules, which may expose wildlife, were
determined using the Fletcher nomogram followed by a first order decline
model TREX 1.3.1 (Details in appendix D). No terrestrial plant data were
available; therefore, no risk assessment was conducted for terrestrial
plants.

The risk hypothesis stated that the use of naphthalene has the potential
to cause adverse effects to terrestrial animals and plants. The risk
hypothesis is confirmed for birds, terrestrial-phase amphibians,
reptiles and mammals, and for adverse effects to non-target terrestrial
animals and plants via indirect effects resulting from potential effects
to birds, terrestrial-phase amphibians, reptiles and mammals. However,
for terrestrial plants, due to lack of data, it is uncertain if
terrestrial plants inhabiting areas adjacent to a treated area would be
at risk for adverse effects to growth and development from naphthalene
uses. Furthermore, as stated previously, the proposed labels state that
the products should not be applied directly to foliage or stems. This
statement indicates that there is a possibility of phytotoxicity.

> **a. Birds**

Naphthalene is categorized as practically nontoxic to upland game birds
(Northern bobwhite quail) on an acute oral (2690 mg/kg bw) and subacute
dietary (\>5620 mg/kg diet) basis. No acute studies with the mallard
duck are available; therefore, it is uncertain if naphthalene is toxic
to waterfowl even though naphthalene is not toxic to upland game birds.
In the oral study, sublethal effects of ruffled appearance, depression,
reduced reaction to external stimuli, loss of coordination, lower limb
weakness prostrate posture, lethargy and loss of righting reflex were
more pronounced at the beginning of the test; at test termination, all
surviving birds appeared normal. Based on LD~50~/ft^2^ exposure method
and an avian oral LD~50~ of 2690 mg/kg bw, the Acute Risk, Acute
Restricted Use, and Endangered Species LOCs were exceeded for all weight
classes birds exposed to naphthalene granules at the maximum application
rate of 10.8 lb/A (see Table III-2). At the minimum application rate of
0.56 lb/A (Table III-3), the Acute Risk, Acute Restricted Use and
Endangered Species LOCs were exceeded for all weight classes birds,
except for 1000 g birds which only the Acute Restricted Use and
Endangered Species LOCs are exceeded.

LD~50~ (mg/kg-bw) values from acceptable or supplemental toxicity
studies that are then adjusted for the size of the animal tested
compared with the size of the animal being assessed (e.g., 20-gram
bird). For the use of naphthalene on ornamentals, flowering beds and
perimeter of buildings, the highest EEC is 23429.24 mg ai/sq. ft. The
adjusted LD~50~ for a 20 g bird would be 1937.96 mg ai/kg-bw. The
LD~50~/sq ft for a 20 g bird would be 604.48.[^11] The result Table
III-4 summarizes this comparison. See Appendix D for T-REX modeling
calculations and results following the application of 10.8 and 0.56
lbs/A for birds.

+------------------------+----------+-----------------+----------------+
| **Table III-4.         |          |                 |                |
| Comparison of Avian    |          |                 |                |
| Acute Toxicity Values  |          |                 |                |
| with Predicted EECs on |          |                 |                |
| Granule Consumption**  |          |                 |                |
+------------------------+----------+-----------------+----------------+
| **Application Rate**   | **Weight | **Naphthalene   |                |
|                        | class    | Estimates**     |                |
|                        | (g)**    |                 |                |
+------------------------+----------+-----------------+----------------+
|                        |          | **Predicted     | **Adjusted     |
|                        |          | EEC**           | LD~50~ ^a^**   |
|                        |          |                 |                |
|                        |          | **(mg ai/sq     | **(mg          |
|                        |          | ft)**           | ai/kg-bw)**    |
+------------------------+----------+-----------------+----------------+
| 10.8 lbs/A             | 20       | 23429.24        | 1937.96        |
+------------------------+----------+-----------------+----------------+
|                        | 100      | 23429.24        | 2467.11        |
+------------------------+----------+-----------------+----------------+
|                        | 1000     | 23429.24        | 3484.89        |
+------------------------+----------+-----------------+----------------+
| 0.56 lbs/A             | 20       | 1214.85         | 1937.96        |
+------------------------+----------+-----------------+----------------+
|                        |          |                 |                |
+------------------------+----------+-----------------+----------------+
|                        | 100      | 1214.85         | 2467.11        |
|                        |          |                 |                |
|                        | 1000     | 1214.85         | 3484.89        |
+------------------------+----------+-----------------+----------------+
| ^a^ LD~50~ = 2690      |          |                 |                |
| mg/kg-bw               |          |                 |                |
+------------------------+----------+-----------------+----------------+

To better characterize the risks to birds, this screening risk
assessment also estimates the minimum foraging area (square feet) needed
to allow for direct ingestion of sufficient mass of naphthalene to
achieve a dose that exceeds the adjusted LD~50~ by assuming that a bird
consumes 100%, 50% or 10% of the available granules depending on bird's
weight class. In order to derive a first approximation of acute exposure
and risk to granular naphthalene for birds that may directly consume
granules, the TREX model takes into account that naphthalene granules do
not repel but attract birds and that 100% of avian diet is comprised of
naphthalene granules. By comparing this estimated concentration at 10.8
lb/A to the corresponding acute oral toxicity reference value for birds
(LD~50~ = 2690 mg/kg-bw for birds (MRID 148176)); acute LD~50~/ft^2^s
were calculated and compared to the Agency's LOCs. Subsequently, the
LD~50~/ft^2^ for birds, in general, resulting from exposure to 10.8 lb/A
granular naphthalene was 8.7; the Agency's LOCs for acute risk (0.5),
acute restricted use (LOC 0.2), and acute endangered species (LOC 0.1)
were all exceeded. The LD~50~/ft^2^ for birds, in general, resulting
from exposure to 0.56 lb/A granular naphthalene was 0.45; the Agency's
LOCs for acute restricted use and endangered species were exceeded.

Although it seems unreasonable to assume that naphthalene granules may
be consumed by birds since it is not formulated as an attractant but as
a repellent to terrestrial animals and is comprised of granules with a
strong odor of coal tar, it is uncertain if the repellent nature of the
compound will be sufficient to keep birds away. The reason of the
uncertainty is based on the acute dietary study (MRID 148175) of
naphthalene to 13-day old bobwhite quails, the 5-day LC~50~ was \>5620
mg/kg-diet but the NOAEC was 1000 mg/kg-diet due to reductions in
percentage of body weight while food consumption of treated birds were
higher (9-15 g/bird/day) than the control birds (8.6 g/bird/day).
Nevertheless, the TREX model assumes birds are exclusively attracted to
naphthalene and their diets are 100% granules, which represents a
conservative scenario due to species-specific feeding habits and dietary
requirements. Therefore, EFED has taken further steps to characterize
the potential for acute risk to avian species by evaluating how much
area would need to be foraged to achieve the amount of naphthalene
granules necessary to trigger the Agency's Levels of Concern (LOCs).
Table III-5 calculates the number of granules and minimum foraging area
needed to exceed Agency's LOCs at 10.8 lb/A granular naphthalene.

  --------------------------- --------------------- ----------- --------- ----------
  **Table III-5. Estimates of                                             
  the number of granules, and                                             
  minimum area foraged needed                                             
  for a 20g, 100g, and 1000g                                              
  bird to achieve the EEC                                                 
  that would trigger an                                                   
  exceedance of the adjusted                                              
  LD50, acute risk LOC (0.5),                                             
  and endangered species risk                                             
  (0.5) levels of concern                                                 
  (LOCs) based on an                                                      
  application rate of 10.8                                                
  lb/A**                                                                  

                                                    **Bird Size           
                                                    (grams)**             

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

  No. of Consumed Granules    Adjusted LD~50~       1           7         92
  Required to Reach the                                                   
  Specified LOC                                                           

                              Acute Risk LOC (0.5)  0.51        4         46

                              Endangered Species    0.1         0.65      10
                              LOC (0.1)                                   

  Area of Field to be Foraged Assuming a 100%       0.03        0.22      3.1
  (square feet) to Achieve    Feeding Efficiency                          
  the Endangered Species LOC                                              
  Based on Application Rate                                               
  of 10.8 lb/A.\*                                                         

                              Assuming a 50%        0.07        0.44      6.2
                              Feeding Efficiency                          

                              Assuming a 10%        0.34        2.19      31
                              Feeding Efficiency                          

  \* Immediate EEC = 112.46                                               
  mg/square feet (excluding                                               
  row spacing, bandwidth, and                                             
  \# of rows input                                                        
  parameters)                                                             
  --------------------------- --------------------- ----------- --------- ----------

For instance, it was estimated that a 20-g bird would need to consume
0.1 granules to exceed the endangered species LOC. Based on the maximum
application rate of 10.8 lb/A, this number of granules could be gleaned
from 0.03, 0.07, or 0.34 square feet (within the treated band) when
assuming a 100%, 50%, or 10% feeding efficiency, respectively. To
achieve an EEC equivalent dose that would result in an exceedance of the
endangered species LOC, a 1000g bird would have to consume 10 granules.
It was estimated that this number of granules could be consumed in an
area of 3.1, 6.2, or 31 square feet when assuming a 100%, 50%, or 10%
feeding efficiency, respectively.

Table III-6 calculates the number of granules and minimum foraging area
needed to exceed Agency's LOCs at the minimum application rate of 0.56
lb/A granular naphthalene.

  --------------------------- --------------------- ----------- --------- ----------
  **Table III-6. Estimates of                                             
  the number of granules, and                                             
  minimum area foraged needed                                             
  for a 20g, 100g, and 1000g                                              
  bird to achieve the EEC                                                 
  that would trigger an                                                   
  exceedance of the adjusted                                              
  LD50, acute risk LOC (0.5),                                             
  and endangered species risk                                             
  (0.5) levels of concern                                                 
  (LOCs) based on an                                                      
  application rate of 0.56                                                
  lb/A**                                                                  

                                                    **Bird Size           
                                                    (grams)**             

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

  No. of Consumed Granules    Adjusted LD~50~       1           7         92
  Required to Reach the                                                   
  Specified LOC                                                           

                              Acute Risk LOC (0.5)  0.51        4         46

                              Endangered Species    0.1         0.65      10
                              LOC (0.1)                                   

  Area of Field to be Foraged Assuming a 100%       0.66        4.2       60
  (square feet) to Achieve    Feeding Efficiency                          
  the Endangered Species LOC                                              
  Based on Application Rate                                               
  of 0.56 lb/A.\*                                                         

                              Assuming a 50%        1.3         8.5       120
                              Feeding Efficiency                          

                              Assuming a 10%        6.7         42.3      598
                              Feeding Efficiency                          

  \* Immediate EEC = 5.83                                                 
  mg/square feet (excluding                                               
  row spacing, bandwidth, and                                             
  \# of rows input                                                        
  parameters)                                                             
  --------------------------- --------------------- ----------- --------- ----------

For this screening risk assessment purposes, it is assumed that birds
occupy, exclusively and permanently, the treated area being modeled.
This assumption leads to a maximum level of exposure in the risk
characterization. To the extent that a bird does not reside exclusively
and permanently in the treated areas ingesting naphthalene granules as
their only food source, exposure will be much less and presumably
substantially less. Naphthalene is manufactured as a repellent, so it is
likely that birds will avoid consumption of the naphthalene
flakes/crystals; however, incidental ingestion of naphthalene granules
may be the most likely route of exposure.

a.  **Terrestrial-phase Amphibians and Reptiles**

EFED currently uses data on surrogate species (birds) to assess
non-target terrestrial-phase amphibians and reptiles. Based on the
evaluation of potential risks to birds, potential risks to reptiles and
terrestrial-phase amphibians are also higher than the Agency's levels of
concern. Again, to the extent that a terrestrial-phase amphibian or
reptile does not reside exclusively and permanently in the treated areas
ingesting naphthalene crystals or flakes, exposure will be much less.
Naphthalene is a repellent and it is manufactured to ensure that
reptiles will avoid the naphthalene flakes (e.g., Snake-A-Way).

b.  **Mammals**

Based on LD~50~/ft^2^ exposure method and mammal oral LD~50~ of 2649
mg/kg-bw, the Acute Risk, Acute Restricted Use and Endangered Species
Risk LOC were exceeded for all weight classes (15-, 35- and 1000 g)
mammals exposed to naphthalene granules at both maximum and minimum
application rates (Tables III-2 and III-3). Mammalian species would be
at risk to adverse effects from granular application of naphthalene.
Currently, T-REX does not have the capacity to estimate the minimum
foraging area needed to allow for direct ingestion of sufficient mass of
naphthalene to achieve a dose that exceeds the LOC for mammals.

c.  **Beneficial Insects**

No honeybee contact study has been submitted; therefore, the potential
risks to beneficial insects are unknown.

d.  **Terrestrial Plants**

EFED currently uses terrestrial plant data to estimate potential risks
to non-target terrestrial plants from surface water runoff. No
terrestrial plant studies have been submitted or located in published
literature; therefore, the potential risks to terrestrial plants are
unknown. Therefore, it is uncertain if terrestrial plants inhabiting
areas adjacent to a treated area would be at risk for adverse effects to
growth and development as a result of naphthalene uses. Furthermore, as
stated previously, the proposed labels state that the products should
not be applied directly to foliage or stems. This statement indicates
that there is a possibility of phytotoxicity; in addition, open
literature suggests that naphthalene is selectively phytotoxic to
plants.

**3. Review of Incident Data**

The National Pesticide Information Center (NPIC) prepares summaries of
information provided by individuals who have contacted the NPIC for
information or to report a pesticide incident. None of this information
has been verified or substantiated by independent investigations of NPIC
staff, laboratory analysis, or any other means. Thus, if a person
alleges/reports a pesticide incident, it will likely be recorded by
NPIC. NPIC qualifies the information by assigning a Certainty Index
(CI), which is an indication of the degree of certainty that the
purported incident was related to a pesticide exposure. CIs, range from
1 = "definite" to 5 = "unrelated". NPIC makes no claims or guarantees as
to the accuracy of the CI or other information presented in its reports,
other than that NPIC has done its best to accurately document/record the
information provided to NPIC.

FIFRA 6(a)(2) incident data add lines of evidence to provide evidence
that the risk predictions from the screening level assessment are
substantiated with actual effects in the field. One incident resulting
from naphthalene use has been recorded in the Ecological Incident
Information System (EIIS) as of May 31, 2007. The incident reported
includes possible impact to fish.

+-------+-------+--------+------+---------+--------+-------+--------+
| **For | **C   | **Date | *    | *       | **R    | *     | **Cita |
| mulat | rop** | and    | *Spe | *Number | esidue | *Misc | tion** |
| ion** |       | Loca   | cies | Found** | and    | ellan |        |
|       |       | tion** | Af   |         | ChE**  | eous, |        |
|       |       |        | fect |         |        | App.  |        |
|       |       |        | ed** |         | **Anal | Rate, |        |
|       |       |        |      |         | ysis** | Me    |        |
|       |       |        |      |         |        | thod, |        |
|       |       |        |      |         |        | e     |        |
|       |       |        |      |         |        | tc.** |        |
+=======+=======+========+======+=========+========+=======+========+
| Un    | N/A   | May    | Unk  | 2,000   | No     | Tr    | IO141  |
| known |       | 2003,  | nown |         |        | eated | 23-006 |
|       |       | Craven | fish |         |        | dir   |        |
|       |       | Co.,   |      |         |        | ectly |        |
|       |       | NC     |      |         |        |       |        |
+-------+-------+--------+------+---------+--------+-------+--------+

> **4. Endocrine Effects**

One summarized study (Milton Fingerman, 1996) confirmed naphthalene is
an endocrine disrupter. When elevated in water to 10 mg/L, naphthalene
caused crawfish ovaries to shrink, resulting in fewer eggs and smaller
offspring. However, the open literature data was unavailable for review
for this assessment.

> **5. Federal Threatened and Endangered (Listed) Species Concerns**

Acute endangered species and chronic risk LOCs are considered in this
screening-level risk assessment of pesticide risks to listed species.
Endangered species acute LOCs are a fraction of the non-endangered
species LOCs or, in the case of endangered plants, RQs are derived using
lower toxicity endpoints than non-endangered plants. Therefore, concerns
regarding listed species within a taxonomic group are triggered in
exposure situations where restricted use or acute risk LOCs are
triggered for the same taxonomic group. The risk assessment also
includes an evaluation of the potential probability of individual
effects for exposures that may occur at the established endangered
species LOC in both the risk characterization and the endangered species
sections. This probability is calculated using the established
dose/response relationship and assumes a probit (probability unit)
dose/response relationship. This analysis is presented below.

**a. Action Area**

For listed species assessment purposes, the action area is considered to
be the area potentially 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 the treated site and aquatic animals are assumed to be
located in a surface water body adjacent to the treated site. The
assessment also assumes that the listed species are directly ingesting
the granules or exposed to the wind-borne granules located on an assumed
area that has the relatively highest potential exposure to the
pesticide. Section I.A.3 of this risk assessment presents the pesticide
use sites that are used to establish initial collocation of species with
treatment areas.

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
potential for a "may affect" conclusion exists 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 and could 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 species. These
subsequent refinement steps could consider how this information would
impact the action area for a particular listed species and may
potentially include areas of exposure that are downwind and downstream
of the pesticide use site.

> **b. Taxonomic Groups Potentially at Risk**

The preliminary risk assessment for endangered species indicates that
naphthalene exceeds the Endangered Species LOCs for the specified use
scenario for the following taxonomic groups:

-   Birds (all weight classes), reptiles and terrestrial-phase
    amphibians ingesting granules in the treated area at both high and
    low application rates.

-   Mammals (all weight classes) ingesting granules in the treated area
    at both high and low application rates.

With limited data available, no LOCs were exceeded for freshwater fish,
aquatic-phase amphibians and invertebrates. Data for estuarine/marine
species, beneficial insects and terrestrial/aquatic plants are not
available; it is uncertain if these species would be potentially at risk
when exposed to naphthalene.

**(1) Discussion of Risk Indices**

For a screening-level risk assessment, EFED determines what endangered
species may be affected by performing a screening level assessment. If
the RQs and LD~50~/ft^2^s from this assessment do not exceed the listed
species LOCs, endangered species may not be affected. However, the
Agency's LOC for endangered and threatened birds, reptiles,
terrestrial-phase amphibians and mammals is exceeded for the use of
naphthalene as outlined in previous sections. Should estimated exposure
levels occur in proximity to listed resources, the available screening
level information suggests a potential concern for direct effects on
listed species within these taxonomic groups listed above associated
with the use of naphthalene as described in Section I.A.3

**(2) Probit Dose Response Relationship**

A probit dose response analysis was performed for toxicity studies for
which slopes with 95% confidence intervals were available; these include
freshwater invertebrate (daphnid), freshwater fish (rainbow trout), and
birds (bobwhite quail). Number range CHAPTERThe probit slope response
relationship is evaluated to calculate the chance of an individual event
corresponding to the listed species acute LOCs. 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.
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 slope
cited in Urban and Cook (1986).

Probability of an individual effect was estimated at the acute
endangered species LOC for aquatic and terrestrial animals (Table
III-7). Plants are not included in the probability analysis. This
analysis is presented in the following table.

+-------------+-------------+--------+-----------------+-------------+
| **Table     |             |        |                 |             |
| III-7       |             |        |                 |             |
| Probit Dose |             |        |                 |             |
| Response    |             |        |                 |             |
| R           |             |        |                 |             |
| elationship |             |        |                 |             |
| Analysis**  |             |        |                 |             |
+-------------+-------------+--------+-----------------+-------------+
| **Taxa**    | **Probit    | **Enda | **Estimated     | **Comment** |
|             | Slope (95%  | ngered | Probability of  |             |
|             | confidence  | S      | an Individual   |             |
|             | i           | pecies | Effect at the   |             |
|             | ntervals)** | LOC**  | Endangered      |             |
|             |             |        | Species LOC**   |             |
+-------------+-------------+--------+-----------------+-------------+
| Birds,      | 2.13        | 0.1    | 1 in 6E1        | None        |
| Reptiles    | (           |        |                 |             |
| and         | 0.486-3.78) |        | (1 in 3.19 to 1 |             |
| Terres      |             |        | in 1.28E4)      |             |
| trial-phase | MRID 148176 |        |                 |             |
| Amphibians  |             |        |                 |             |
+-------------+-------------+--------+-----------------+-------------+
| Mammals     | 4.5 (2-9)   | 0.1    | 1 in 2.9E5      | Data        |
|             |             |        |                 | i           |
|             |             |        | (1 in 44 to 1   | nsufficient |
|             |             |        | in 9E18)        | to allow    |
|             |             |        |                 | for probit  |
|             |             |        |                 | slope       |
|             |             |        |                 | derivation; |
|             |             |        |                 | therefore,  |
|             |             |        |                 | the default |
|             |             |        |                 | slope of    |
|             |             |        |                 | 4.5 with    |
|             |             |        |                 | lower and   |
|             |             |        |                 | upper       |
|             |             |        |                 | bounds of 2 |
|             |             |        |                 | -- 9 was    |
|             |             |        |                 | used.       |
+-------------+-------------+--------+-----------------+-------------+
| Fish and    | 12.9 (7.8   | 0.05   | 1 in 6E62       | None        |
| Aq          | -- 18)      |        |                 |             |
| uatic-phase |             |        | (1 in 5.9E23 to |             |
| Amphibians  | MRID        |        | 1 in 7E120)     |             |
|             | 46030801    |        |                 |             |
+-------------+-------------+--------+-----------------+-------------+
| Aquatic     | 5.9         | 0.05   | 1 in 1.2E14     | None        |
| In          | (1.4-10.3)  |        |                 |             |
| vertebrates |             |        | (1 in 29 -- 1   |             |
|             | MRID        |        | in 3.3E40)      |             |
|             | 44302702    |        |                 |             |
+-------------+-------------+--------+-----------------+-------------+

**(3) Data Related to Under-represented Taxa**

Data are not available to evaluate effects to under-represented taxa.

**(4) Implications of Sublethal Effects**

The only sublethal effect observed in the acute terrestrial animal
studies is a decrease in body weight in the bobwhite quail acute oral
study with a NOAEC of 1000 mg/kg-bw. No sublethal effects were reported
in any of the acute studies conducted with aquatic species.

c.  **Indirect Effect Analysis**

The endangered species LOC for non-target animals was exceeded for
birds, reptiles, terrestrial-phase amphibians and mammals located in the
treated areas ingesting granules for the scenarios analyzed. The
guideline survival studies indicate direct adverse effects to 20-, 100-,
and 1000-gram birds, reptiles, terrestrial-phase amphibians and 15-,
35-, and 1000-gram mammals.

Adverse effects to birds, reptiles, terrestrial-phase amphibians and
mammals may be sufficient to prevent the animals from competing
successfully with other animals for resources and water. Endangered
species may be especially impacted by exposure to naphthalene because of
the impact of the loss of a few individuals to the population. There is
a potential concern for listed species with either broad or narrow
dependencies on impacted bird, reptile, terrestrial-phase amphibian and
mammal species/populations/communities for habitat, feeding, burrowing
or cover requirements.

d.  **Critical Habitat**

In the evaluation of pesticide effects on designated critical habitat,
consideration is given to the physical and biological features
(constituent elements) of a critical habitat identified by the U.S. Fish
and Wildlife and National Marine Fisheries Services as essential to the
conservation of a listed species and which may require special
management considerations or protection. The evaluation of impacts for a
screening level pesticide risk assessment focuses on the biological
features that are constituent elements and is accomplished using the
screening-level taxonomic analysis (risk indices, RQs or LD~50~/ft^2^s)
and listed species levels of concern (LOCs) that are used to evaluate
direct and indirect effects to listed species.

The screening-level risk assessment has identified potential concerns
for indirect effects on listed species for those animals and plants
dependant upon birds, reptiles, terrestrial-phase amphibians and
mammals. In light of the potential for indirect effects, 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 whether the pesticide's potential 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 is
potentially impacted directly by the use of the pesticide. EPA and the
Service(s) are working together to conduct the necessary analysis.

This screening-level risk assessment for critical habitat provides a
listing of potential biological features that, if they are constituent
elements of one or more critical habitats, would be of potential
concern. These correspond to the taxa identified above as being of
potential concern for indirect effects and include the following: birds,
reptiles, terrestrial-phase amphibians and mammals. This list should
serve as an initial step in problem formulation for further assessment
of critical habitat impacts outlined above, should additional work be
necessary.

e.  **Direct Effect Co-occurrence Analysis**

Because the Endangered Species LOC for birds, reptiles,
terrestrial-phase amphibians and mammals is exceeded for the proposed
use of naphthalene, LOCATES was run for all listed birds, reptiles,
terrestrial-phase amphibians and mammals to determine the potential for
co-occurrence of listed animal species location with areas of expected
pesticide use. However, no preliminary analysis was performed for
non-food uses of naphthalene because the LOCATES tool does not include
county-level location information for the proposed non-food use of
naphthalene. The animal taxa that reside in those areas, and the basis
for the designation, are in Appendix G. Consequently, based on the
information available at this step in the assessment process, it is
presumed that all listed animal species are potentially directly
affected from the broad range of naphthalene proposed uses which include
areas around houses, cabins, trailers, garages, utility houses, barns,
woodpiles, sand piles, trash cans, flower beds, plants (ornamentals,
roses, spring bulbs), around the periphery of gardens, and garbage bags
placed near residences and other buildings, streets or alleys for
garbage collection. Additional analysis of listed animal locations,
refinement of the action area associated with naphthalene regulatory
decisions, and the biology of the potentially affected species would be
needed before an effects determination can be made for any of the
co-located species identified by this assessment.

LOCATES listed 500 endangered/threatened birds, reptiles,
terrestrial-phase amphibians, and mammals found nationwide.
Consequently, based on the information available, it is presumed listed
species reside in areas of expected pesticide use (Table III-8).

  ----------------- ----------------- ----------------- -----------------
  **Table III-8.                                        
  Number of Listed                                      
  Species Located                                       
  in Non-Food Areas                                     
  in the United                                         
  States of                                             
  America**                                             

  **Non-food Use**  **Affected        **Affected        **No. of
                    Counties**        States**          Species**

  Ornamentals,      All               50                500
  gardens, and the                                      
  perimeters of                                         
  structural                                            
  buildings                                             
  ----------------- ----------------- ----------------- -----------------

f.  **Indirect Effect Co-occurrence Analysis**

The screening-level risk indices for birds, reptiles, terrestrial-phase
amphibians and mammals exceed the LOC for endangered species. In
accordance with established procedures such findings suggest a potential
concern for indirect effects to listed animal and plant species with
both narrow (i.e., species that are obligates or have very specific
habitat or feeding requirements) and general dependencies (i.e., cover
type requirements) on plants or animals as a resource or important
habitat component. LOCATES was used to preliminarily identify listed
animal and plant species that are located within the counties in USA
where naphthalene could be used. This analysis considered all animal and
plant taxonomic groups (i.e., conifers/cycads, monocots, dicots, ferns,
lichens, insects and arachnids) that eat birds or mammals, plants that
requires birds or mammals as pollinators or seed dispersers, or species
that require reptile or mammal burrows for shelter or breeding habitats.
However, no preliminary analysis was available for non-food use of
naphthalene because the LOCATES tool does not include county-level
location information for the proposed non-food use of naphthalene.
Consequently, based on the information available at this step in the
assessment process, it is presumed that these animal and plant species
are potentially indirectly affected from the broad range of naphthalene
uses which include areas around houses, cabins, trailers, garages,
utility houses, barns, woodpiles, sand piles, trash cans, flower beds,
plants (ornamentals, roses, spring bulbs), around the periphery of
gardens, and garbage bags placed near residences and other buildings,
streets or alleys for garbage collection. The animal and plant species
that reside in those areas, and the basis for the designation, are in
Appendix H and are summarized in Table III-9, below. Such potential
concerns are limited by the true potential for exposures of critical
animal and plant species resources to modeled naphthalene levels and the
relationship between 'directly effected' listed species and 'indirectly
effected' listed species. Consequently, additional analysis of listed
species locations, refinement of the action area associated with
naphthalene regulatory decisions, and the biology of the potentially
affected species would be needed before an effects determination can be
made for any of the co-located species identified by this assessment for
potential indirect effects.

+---------+-----+---------------------+-----+------------------------+
| **Table |     |                     |     |                        |
| III-9.  |     |                     |     |                        |
| Listed  |     |                     |     |                        |
| ta      |     |                     |     |                        |
| xonomic |     |                     |     |                        |
| groups  |     |                     |     |                        |
| pote    |     |                     |     |                        |
| ntially |     |                     |     |                        |
| at risk |     |                     |     |                        |
| ass     |     |                     |     |                        |
| ociated |     |                     |     |                        |
| with    |     |                     |     |                        |
| direct  |     |                     |     |                        |
| or      |     |                     |     |                        |
| i       |     |                     |     |                        |
| ndirect |     |                     |     |                        |
| effects |     |                     |     |                        |
| due to  |     |                     |     |                        |
| appli   |     |                     |     |                        |
| cations |     |                     |     |                        |
| of      |     |                     |     |                        |
| naph    |     |                     |     |                        |
| thalene |     |                     |     |                        |
| on      |     |                     |     |                        |
| areas   |     |                     |     |                        |
| where   |     |                     |     |                        |
| orn     |     |                     |     |                        |
| amental |     |                     |     |                        |
| plants, |     |                     |     |                        |
| fl      |     |                     |     |                        |
| owering |     |                     |     |                        |
| beds    |     |                     |     |                        |
| and     |     |                     |     |                        |
| gardens |     |                     |     |                        |
| are     |     |                     |     |                        |
| grown   |     |                     |     |                        |
| natio   |     |                     |     |                        |
| nwide** |     |                     |     |                        |
+=========+=====+=====================+=====+========================+
| *       | **  | **Basis for Direct  | *   | **Basis for Indirect   |
| *Listed | Dir | Effects Concern**   | *In | Effects Concern**      |
| Taxon** | ect |                     | dir |                        |
|         | Eff |                     | ect |                        |
|         | ect |                     | Eff |                        |
|         | s** |                     | ect |                        |
|         |     |                     | s** |                        |
+---------+-----+---------------------+-----+------------------------+
| Terr    | Yes | Since the product   | Yes | Potential concerns for |
| estrial |     | labels state, "Do   |     | monocots and dicots    |
| and     |     | not apply the       |     | that depend on birds,  |
| Semi-   |     | product directly to |     | reptiles,              |
| Aquatic |     | foliage or stems,"  |     | terrestrial-phase      |
| Plants  |     | this statement      |     | amphibians and mammals |
| --      |     | indicates that      |     | as pollinators or seed |
| m       |     | there is a          |     | dispersers. If         |
| onocots |     | possibility of      |     | pollinators such as    |
| and     |     | phytotoxicity. In   |     | honeybees, beneficial  |
| dicots  |     | addition, open      |     | insects, and           |
|         |     | literature suggests |     | birds/mammals are      |
|         |     | naphthalene is      |     | repelled from          |
|         |     | selectively         |     | naphthalene, there     |
|         |     | phytotoxic to       |     | might be indirect      |
|         |     | plants. However,    |     | effects to plants due  |
|         |     | toxicity data are   |     | to loss of pollinators |
|         |     | not available for   |     | for flower             |
|         |     | terrestrial plants  |     | fertilization.         |
|         |     | exposed to          |     |                        |
|         |     | naphthalene. If     |     |                        |
|         |     | plants are          |     |                        |
|         |     | sensitive to        |     |                        |
|         |     | naphthalene, there  |     |                        |
|         |     | might be direct     |     |                        |
|         |     | effects to plants.  |     |                        |
|         |     | However, the        |     |                        |
|         |     | likelihood for      |     |                        |
|         |     | plants to be at     |     |                        |
|         |     | risk from           |     |                        |
|         |     | naphthalene is low  |     |                        |
|         |     | but cannot be       |     |                        |
|         |     | precluded at this   |     |                        |
|         |     | time.               |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Ho      | No  | No data on          | Yes | Potential concerns for |
| neybees |     | honeybees are       |     | honeybees that depend  |
|         |     | available.          |     | on mammal or reptile   |
|         |     | Naphthalene is      |     | burrows for habitat,   |
|         |     | volatile, so it is  |     | feeding, or cover      |
|         |     | uncertain if        |     | requirements.          |
|         |     | honeybees will be   |     |                        |
|         |     | impacted from       |     |                        |
|         |     | pollinating the     |     |                        |
|         |     | treated areas or if |     |                        |
|         |     | flowers will be     |     |                        |
|         |     | indirectly affected |     |                        |
|         |     | from the absent of  |     |                        |
|         |     | pollinators. The    |     |                        |
|         |     | likelihood of       |     |                        |
|         |     | direct effect to    |     |                        |
|         |     | honeybees is low    |     |                        |
|         |     | but cannot be       |     |                        |
|         |     | precluded at this   |     |                        |
|         |     | time.               |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Birds   | Yes | The endangered      | Yes | Potential concerns for |
| and     |     | species LOC is      |     | birds and reptiles     |
| Rept    |     | exceeded for both   |     | that eat mammals as a  |
| iles^1^ |     | high and low        |     | food resource.         |
|         |     | application rates.  |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Ter     | Yes | The endangered      | Yes | Potential concerns for |
| restria |     | species LOC is      |     | terrestrial-phase      |
| l-phase |     | exceeded for both   |     | amphibians that eat    |
| Amphib  |     | high and low        |     | birds, reptiles and    |
| ians^1^ |     | application rates.  |     | mammals as a food      |
|         |     |                     |     | source or use mammals  |
|         |     |                     |     | and depend on reptile  |
|         |     |                     |     | burrows for habitat    |
|         |     |                     |     | and shelter.           |
+---------+-----+---------------------+-----+------------------------+
| Mammals | Yes | The endangered      | Yes | Potential concerns for |
|         |     | species LOC is      |     | mammals that eat       |
|         |     | exceeded for both   |     | birds, reptiles and    |
|         |     | high and low        |     | terrestrial-phase      |
|         |     | application rates.  |     | amphibians and depend  |
|         |     |                     |     | on reptile burrows for |
|         |     |                     |     | habitat and shelter.   |
+---------+-----+---------------------+-----+------------------------+
| Aquatic | Yes | Since the product   | Yes | Potential concerns for |
| V       |     | labels state, "Do   |     | aquatic vascular       |
| ascular |     | not apply the       |     | plants that depend on  |
| Plants  |     | product directly to |     | birds, reptiles,       |
|         |     | foliage or stems,"  |     | terrestrial-phase      |
|         |     | this statement      |     | amphibians and mammals |
|         |     | indicates that      |     | as pollinators or seed |
|         |     | there is a          |     | dispersers. If         |
|         |     | possibility of      |     | pollinators such as    |
|         |     | phytotoxicity. In   |     | honeybees, beneficial  |
|         |     | addition, open      |     | insects, and           |
|         |     | literature suggests |     | birds/mammals are      |
|         |     | naphthalene is      |     | repelled from          |
|         |     | selectively         |     | naphthalene, there     |
|         |     | phytotoxic to       |     | might be indirect      |
|         |     | plants. However,    |     | effects to plants due  |
|         |     | toxicity data are   |     | to loss of pollinators |
|         |     | not available for   |     | for flower             |
|         |     | aquatic plants      |     | fertilization.         |
|         |     | exposed to          |     |                        |
|         |     | naphthalene. If     |     |                        |
|         |     | plants are          |     |                        |
|         |     | sensitive to        |     |                        |
|         |     | naphthalene, there  |     |                        |
|         |     | might be direct     |     |                        |
|         |     | effects to plants.  |     |                        |
|         |     | However, the        |     |                        |
|         |     | likelihood for      |     |                        |
|         |     | plants to be at     |     |                        |
|         |     | risk from           |     |                        |
|         |     | naphthalene is low  |     |                        |
|         |     | but cannot be       |     |                        |
|         |     | precluded at this   |     |                        |
|         |     | time.               |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Fre     | No  | No LOC exceedances  | Yes | If plants are directly |
| shwater |     |                     |     | or indirectly affected |
| Inverte |     |                     |     | from exposure to       |
| brates, |     |                     |     | naphthalene,           |
| Fish    |     |                     |     | freshwater fish and    |
| and     |     |                     |     | amphibians may be      |
| Aquati  |     |                     |     | indirectly affected    |
| c-phase |     |                     |     | due to loss of cover   |
| A       |     |                     |     | or food sources.       |
| mphibia |     |                     |     |                        |
| ns^2,3^ |     |                     |     |                        |
+---------+-----+---------------------+-----+------------------------+
| Es      | No  | No LOC exceedances  | Yes | If plants are directly |
| tuarine |     |                     |     | or indirectly affected |
| /marine |     |                     |     | from exposure to       |
| Fish    |     |                     |     | naphthalene,           |
| and     |     |                     |     | estuarine/marine fish  |
| Invert  |     |                     |     | and invertebrates may  |
| ebrates |     |                     |     | be indirectly affected |
|         |     |                     |     | due to loss of cover   |
|         |     |                     |     | or food.               |
+---------+-----+---------------------+-----+------------------------+
| Aquatic | No  | No LOC exceedances  | Yes | Potential concerns for |
| Nonv    |     |                     |     | aquatic nonvascular    |
| ascular |     |                     |     | plants that depend on  |
| Plants  |     |                     |     | birds, reptiles,       |
| --      |     |                     |     | terrestrial-phase      |
| algae   |     |                     |     | amphibians and mammals |
| and     |     |                     |     | as pollinators and     |
| diatoms |     |                     |     | seed dispersers. If    |
|         |     |                     |     | pollinators such as    |
|         |     |                     |     | honeybees, beneficial  |
|         |     |                     |     | insects, and           |
|         |     |                     |     | birds/mammals are      |
|         |     |                     |     | repelled from          |
|         |     |                     |     | naphthalene, there     |
|         |     |                     |     | might be indirect      |
|         |     |                     |     | effects to plants due  |
|         |     |                     |     | to loss of pollinators |
|         |     |                     |     | for flower             |
|         |     |                     |     | fertilization.         |
+---------+-----+---------------------+-----+------------------------+
| 1 Birds |     |                     |     |                        |
| are     |     |                     |     |                        |
| used as |     |                     |     |                        |
| su      |     |                     |     |                        |
| rrogate |     |                     |     |                        |
| species |     |                     |     |                        |
| for     |     |                     |     |                        |
| ter     |     |                     |     |                        |
| restria |     |                     |     |                        |
| l-phase |     |                     |     |                        |
| amp     |     |                     |     |                        |
| hibians |     |                     |     |                        |
| and     |     |                     |     |                        |
| re      |     |                     |     |                        |
| ptiles; |     |                     |     |                        |
| the     |     |                     |     |                        |
| refore, |     |                     |     |                        |
| po      |     |                     |     |                        |
| tential |     |                     |     |                        |
| direct  |     |                     |     |                        |
| and     |     |                     |     |                        |
| i       |     |                     |     |                        |
| ndirect |     |                     |     |                        |
| effects |     |                     |     |                        |
| to      |     |                     |     |                        |
| end     |     |                     |     |                        |
| angered |     |                     |     |                        |
| avian,  |     |                     |     |                        |
| ter     |     |                     |     |                        |
| restria |     |                     |     |                        |
| l-phase |     |                     |     |                        |
| amp     |     |                     |     |                        |
| hibians |     |                     |     |                        |
| and     |     |                     |     |                        |
| re      |     |                     |     |                        |
| ptilian |     |                     |     |                        |
| species |     |                     |     |                        |
| are     |     |                     |     |                        |
| con     |     |                     |     |                        |
| sidered |     |                     |     |                        |
| equi    |     |                     |     |                        |
| valent. |     |                     |     |                        |
|         |     |                     |     |                        |
| 2 Fish  |     |                     |     |                        |
| are     |     |                     |     |                        |
| used as |     |                     |     |                        |
| a       |     |                     |     |                        |
| su      |     |                     |     |                        |
| rrogate |     |                     |     |                        |
| for     |     |                     |     |                        |
| aquatic |     |                     |     |                        |
| phase   |     |                     |     |                        |
| amph    |     |                     |     |                        |
| ibians; |     |                     |     |                        |
| the     |     |                     |     |                        |
| refore, |     |                     |     |                        |
| po      |     |                     |     |                        |
| tential |     |                     |     |                        |
| direct  |     |                     |     |                        |
| and     |     |                     |     |                        |
| i       |     |                     |     |                        |
| ndirect |     |                     |     |                        |
| effects |     |                     |     |                        |
| to      |     |                     |     |                        |
| end     |     |                     |     |                        |
| angered |     |                     |     |                        |
| fish    |     |                     |     |                        |
| and     |     |                     |     |                        |
| aquati  |     |                     |     |                        |
| c-phase |     |                     |     |                        |
| am      |     |                     |     |                        |
| phibian |     |                     |     |                        |
| species |     |                     |     |                        |
| are     |     |                     |     |                        |
| con     |     |                     |     |                        |
| sidered |     |                     |     |                        |
| equi    |     |                     |     |                        |
| valent. |     |                     |     |                        |
+---------+-----+---------------------+-----+------------------------+

**D. Assumptions, Uncertainties, Strengths and Limitations of the
Naphthalene Assessment.**

*Maximum use scenario*

This screening-level risk assessment relies on labeled statements of the
maximum rate of naphthalene applications, the maximum number of
applications, and the shortest interval between applications. Together,
these assumptions constitute a maximum use scenario and can overestimate
risk. However, the maximum use scenario must be considered because it is
a reflection of the allowable use of naphthalene. The frequency at which
actual uses approach these maximums is dependent on the number and
timing of applications, and market forces. In addition, rates of
application less than the maximum rate are also considered.

*Lack of data on degradates*

There are several areas of uncertainty in the terrestrial and the
aquatic species risk assessments that could potentially cause an
underestimation of risk. First, this assessment accounts only for
exposure of non-target species to naphthalene, but not to its
degradates. The risks presented in this assessment could be
underestimated if degradates also exhibit toxicity under the conditions
of use proposed on the label. Review of available open literature data
concerning the fate and toxicity of the transformation products of
naphthalene was limited to which degradates were observed but did not
provide information on the conditions under which degradates were
formed, the timing of formation, and what amounts were observed, and how
quickly (if at all) the degradates degraded.

*Uncertainties with GENEEC 2 model*

Extrapolating the risk conclusions from the standard pond scenario
modeled by GENEEC2 may either underestimate or overestimate the
potential risks. Major uncertainties with the standard runoff scenario
are associated with the physical construct of the watershed and
representation of vulnerable aquatic environments for different
geographic regions. The physicochemical properties (pH, redox
conditions, etc.) of the standard farm pond are based on a Georgia farm
pond. These properties are likely to be regionally specific because of
local hydrogeological conditions. Any alteration in water quality
parameters may impact the environmental behavior of the pesticide,
depending upon the specific properties of a given chemical (for example,
pH and dependant hydrolysis). The farm pond represents a well-mixed,
static water body. Because the farm pond is a static water body (no flow
through), it does not account for pesticide removal through flow through
or accidental water releases. However, the lack of water flow in the
farm pond provides an environmental condition for accumulation of
persistent pesticides. The assumption of uniform mixing does not account
for stratification due to thermoclines (e.g., seasonal stratification in
deep water bodies). Additionally, the physical construct of the standard
runoff scenario assumes a watershed:pond area ratio of 10 to 1. This
ratio is recommended to maintain a sustainable pond in the Southeastern
United States. The use of higher watershed:pond ratios (As recommended
for sustainable ponds in drier regions of the United States) may lead to
higher pesticide concentrations when compared to the standard
watershed:pond ratio.

*Location of wildlife species*

For screening terrestrial risk assessments for listed species, a generic
bird or mammal is assumed to occupy either the treated field or adjacent
areas receiving or ingesting pesticide at a rate commensurate with the
treatment rate on the field. Model predictions suggest that this
assumption leads to an overestimation of exposure to species that do not
occupy the treated field or do not ingest naphthalene granules
(crystals/flakes). The actual habitat requirements of any particular
terrestrial species are not considered, and it is assumed that species
occupy, exclusively and permanently, the treatment area being modeled.
This assumption leads to a maximum level of exposure in the risk
characterization. To the extent that a species does not reside
exclusively and permanently in treated areas, exposure will be less, and
presumably less. As for the case with naphthalene used as a repellent to
keep species away from treated areas, it is likely that terrestrial
species will not occupy the treatment area permanently or attempt to
ingest naphthalene granules. However, incidental ingestion of the
naphthalene granules is likely.

*Routes of exposure*

Screening-level risk assessments for granular applications of pesticides
consider dietary exposure alone. Other routes of exposure, not
considered in this assessment, are discussed below:

-   Incidental soil ingestion exposure

This risk assessment does not consider incidental soil ingestion;
however, since naphthalene repels unwanted species to the treated sites,
incidental soil ingestion may not need to be considered.

-   Inhalation exposure

The screening risk assessment does not consider inhalation exposure.
Such exposure may occur through two potential sources: (1) vapor phase
pesticide volatilizing from treated surfaces and (2) airborne
particulate (soil, vegetative material, and pesticide
dusts/crystals/flakes).

Theoretically, inhalation of pesticide active ingredient in the vapor
phase may be another source of exposure for some pesticides under some
exposure situations. However, considering its moderate vapor pressure
value (8.5 x10^-2^ mm Hg), it is uncertain that naphthalene will exist
in the gaseous phase at any considerable amount to cause any adverse
effects via inhalation.

The impact from exposure to dusts/flakes/crystals contaminated with the
pesticide cannot be assessed generically as partitioning issues related
to application site soils and chemical properties render the exposure
potential from this route highly situation specific.

-   Dermal exposure

The screening assessment does not consider dermal exposure, except as it
is indirectly included in calculations of risk indices based on lethal
doses per unit of pesticide treated area. Dermal exposure may occur
through three potential sources: (1) direct application of
flakes/crystals to terrestrial wildlife in the treated area, (2)
incidental contact with contaminated vegetation, or (3) contact with
contaminated water or soil.

The available measured data related to wildlife dermal contact with
pesticides are extremely limited. The Agency is actively pursuing
modeling techniques to account for dermal exposure via direct
application of granules and by incidental contact with vegetation.

*Dietary Intake -- The Differences between Laboratory and Field
Conditions*

The acute and chronic characterization of risk rely on comparisons of
wildlife dietary residues with LC~50~ or NOAEC values expressed in
concentrations of pesticides in laboratory feed. These comparisons
assume that ingestion of granules in the field occurs at rates
commensurate with those in the laboratory. Although the screening
assessment process adjusts dry-weight estimates of food intake to
reflect the increased mass in fresh weight wildlife food intake
estimates, it does not allow for gross energy and assimilative
efficiency differences between wildlife food items and laboratory feed.

On gross energy content alone, direct comparison of a laboratory dietary
concentration- based effects threshold to a fresh-weight pesticide
residue estimate would result in an underestimation of field exposure by
food consumption by a factor of 1.25 -- 2.5 for most food items. Only
for seeds would the direct comparison of dietary threshold to residue
estimate lead to an overestimate of exposure.

Differences in assimilative efficiency between laboratory and wild diets
suggest that current screening assessment methods do not account for a
potentially important aspect of food requirements. Depending upon
species and dietary matrix, bird assimilation of wild diet energy ranges
from 23 -- 80%, and mammal's assimilation ranges from 41 - 85% (U.S.
Environmental Protection Agency, 1993). If it is assumed that laboratory
chow is formulated to maximize assimilative efficiency (e.g., a value of
85%), a potential for underestimation of exposure may exist by assuming
that consumption of food in the wild is comparable with consumption
during laboratory testing. In the screening process, exposure may be
underestimated because metabolic rates are not related to food
consumption.

Finally, the screening procedure does not account for situations where
the feeding rate may be above or below requirements to meet free-living
metabolic requirements. Gorging behavior is a possibility under some
specific wildlife scenarios (e.g., bird migration) where the food intake
rate may be greatly increased. Kirkwood (1983) has suggested that an
upper-bound limit to this behavior might be the typical intake rate
multiplied by a factor of 5.

In contrast is the potential for avoidance, operationally defined as
animals responding to the presence of noxious chemicals in their food by
reducing consumption of treated dietary elements. This response is seen
in nature where herbivores avoid plant secondary compounds or in this
case, avoid chemicals that specifically repel unwanted species visiting
the treated site.

*Use of the most sensitive species tested*

A small number of surrogate species were used in this screening level
risk assessment. It is not possible to determine whether the species
tested are more or less sensitive than species that may be exposed to
naphthalene. Also, it was assumed that fish are approximately as
sensitive as aquatic-phase amphibians and that bird are approximately as
sensitive as terrestrial-phase amphibians and reptiles. However, no data
are available to support these conclusions.

*Lack of field studies*

Although not required, field studies would assist in determining the
actual extent of potential indirect effects to plants that depends on
mammals and birds as pollinators and to animals that depends on reptile
or mammal burrows for shelter and habitat.

*Age class and sensitivity of effect thresholds*

It is generally recognized that test organism age may have a significant
impact on the observed sensitivity to a toxicant.

The screening risk assessment acute toxicity data for fish are collected
on juvenile fish between 0.1 and 5 grams. Aquatic invertebrate acute
testing is performed on recommended immature age classes (e.g., first
instar for daphnids, second instar for amphipods, stoneflies and
mayflies, and third instar for midges).

Acute dietary testing with birds is performed on juveniles, with mallard
being 5-10 days old and bobwhite quail 10-14 days old.

Testing of juveniles may overestimate toxicity at older age classes for
pesticidal active ingredients because younger age classes may not have
the enzymatic systems associated with detoxifying xenobiotics. The
screening risk assessment has no current provisions for a generally
applied method that accounts for this uncertainty. In so far as the
available toxicity data may provide ranges of sensitivity information
with respect to age class, the risk assessment uses the most sensitive
life-stage information as the conservative screening endpoint.

*Acute and Chronic LOCs*

The risk characterization section of this assessment includes an
evaluation of the potential for individual effects at an exposure level
equivalent to the LOC. This evaluation is based on the median lethal
dose estimate and dose/response relationship established for the effects
study corresponding to each taxonomic group for which the LOCs are
exceeded. The dose-response curve representing a given taxa is generated
from one study using one species. It is likely that the resulting
dose-response relationship does not represent the response of all
species within a taxa.

The risk estimates are based on acute and chronic effects in the
laboratory; therefore, these risk estimates do not directly take into
account uncertainties such as laboratory-to-field sensitivity
differences. These include uncertainty regarding the error introduced
when extrapolating from laboratory to field effects at a given
concentration. For example, mortality in the field could be greater in
populations previously stressed by other pesticide exposures,
temperature stress, habitat loss, predation, or competition for limited
resources. Field mortality and reduction in growth and reproduction
could be lower if the laboratory population were to represent an
unusually sensitive species.

**IV. LITERATURES CITED**

U.S. EPA. 2004a. Overview of the Ecological Risk Assessment Process in
the Office of Pesticide Programs, U.S. Environmental Protection Agency.
Endangered and Threatened Species Effects Determinations. Office of
Prevention, Pesticides and Toxic Substances. Office of Pesticide
Programs. Washington, D.C. January 23, 2004.

U.S. EPA. 2004b. Interim Guidance of the Evaluation Criteria for
Ecological Toxicity Data in the Open Literature. Phases I and II.
Procedures for Identifying, Selecting and Acquiring Toxicity Data
Published in the Open Literature for Use in Ecological Risk Assessments.
Office of Pesticide Programs. July 16, 2004.

U.S. EPA. 2000. Wildlife Exposure Factors Handbook. Office of Research
and Development, Washington, D.C. EPA/600/R-93/187. December 1993.

U.S. Department of Health and Human Services, 2005. Toxicological
Profile for Naphthalene, 1-Methylnaphthalene, and 2-Methylnaphthalene.
Public Health Service, Agency for Toxic Substances and Disease Registry.
August 2005.

U.S. National Park Service, 1997. Environmental Contaminants
Encyclopedia -- Naphthalene Entry. Water Resources Divisions, Water
Operations Branch, Ft Collins, Colorado. July 1, 1997.

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. In F. Coulston and F. Korte, *eds.*,
Environmental Quality and Safety: Chemistry, Toxicology, and Technology,
Georg Thieme Publ, Stuttgart, West Germany, pp. 9-28. Support Document
\# 14.

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

[^1]: www.epa.gov/waterscience/pc/ambientwqc/naphthalene80.pdf

[^2]: http://www.atsdr.cdc.gov/toxprofiles/tp67.pdf

[^3]: <http://en.wikipedia.org/wiki/Naphthalene>

[^4]: <http://en.wikipedia.org/wiki/Polycyclic_aromatic_hydrocarbons>

[^5]: <http://cat.inist.fr/?aModele=afficheN&cpsidt=13944427> and
    <http://cat.inist.fr/?aModele=afficheN&cpsidt=1407090>

[^6]: Information obtained from Naphthalene SMART meeting, March 28,
    2007.

[^7]: mg ai/ft^2^ = [application rate x % active ingredient x 453,590
    mg/lb]{.underline} ~x~ % incorporation

    no. of rows/acre x row length x bandwidth

[^8]: See <http://www.epa.gov/oppefed1/models/water/index.htm> for more
    details.

[^9]: T-REX, 2005. See <http://www.epa.gov/oppefed1/models/terrestrial/>
    for more information

[^10]: The exact mass of naphthalene per flakes was not provided;
    however, information obtained from Naphthalene SMART meeting, March
    28, 2007 was used to estimate the weight.

[^11]: **LD~50~ ft^-2^ =** EEC (mg a.i./ft^2^) / (Adj. LD~50~ x bw (kg)
    of assessed animal) = (23429 mg ai/sq ft) / (1937 mg/kg bw x .02 kg)
    = 604