Number range CHAPTER![](media/image1.wmf){width="1.5in"
height="0.7055555555555556in"}

Date: 03/10/08

**SUBJECT:** Ecological Hazard and Environmental Risk Assessment RED
Chapter for Inorganic Arsenical Wood Preservatives (CCA)

Case No.: 0132

PC Codes: 006802 -- arsenic acid

021101 -- chromic acid

042401 -- cupric oxide

**FROM:** Richard C. Petrie, Agronomist, Team 3 Leader

OPP/AD/RASSB

Antimicrobial Division (7510P)

THRU : Norm Cook.

Chief, RASSB

Antimicrobial Division (7510P)

TO: Tim McMahon, PhD., Senior Toxicologist and Risk Assessor

Immediate Office Staff

Antimicrobials Division (7510P)

And

Lance Wormell, CRM for CCA-C RED

Regulatory Management Branch II

Antimicrobials Division (7510P)

Please find attached the Ecological Hazard and Environmental Risk
Assessment for inorganic arsenical wood preservatives (CCA).

**INORGANIC ARSENICAL WOOD PRESERVATIVES (CCA)**

**ECOLOGICAL HAZARD AND RISK ASSESSMENT FOR THE REREGISTRATION
ELIGIBILITY DECISION (RED) DOCUMENT**

> **PC Codes:**
>
> **Arsenic Acid -- 006802**
>
> **Chromic Acid -- 021101**
>
> **Cupric Oxide - 042401**
>
> **Case No.: 0132**
>
> **Date: 03/10/08**
>
> **Author: Richard C. Petrie**
>
> **Antimicrobials Division**
>
> **Office of Pesticide Programs**
>
> **U.S. Environmental Protection Agency**
>
> **1200 Pennsylvania Avenue, NW**
>
> **Washington, DC 20460**

**TABLE OF CONTENTS**

**[Page No.]{.underline}**

LIST OF TABLES ii

LIST OF APPENDICES ii

EXECUTIVE SUMMARY 3

I.  Ecological Effects Hazard
    Summary.........................................................\......6

    A.  Toxicity to Terrestrial
        Animals............................................................6

        i.  Birds
            acute...........................................................................6

        ii. Birds
            chronic........................................................................8

        iii. Mammals acute and
             subacute.....................................................9

        iv. Mammals
            chronic.................................................................10

        v.  Insects..............................................................................12

    B.  Toxicity to Freshwater Aquatic
        Animals..............................................12

        i.  Freshwater fish
            acute............................................................12

        ii. Freshwater fish
            chronic..........................................................14

        iii. Freshwater invertebrates
             acute..................................................15

        iv. Whole sediment invertebrates
            acute...........................................16

        v.  Freshwater invertebrates
            chronic...............................................16

        vi. Freshwater field
            study............................................................17

        vii. Freshwater organisms
             literature.................................................18

    C.  Toxicity to Estuarine/Marine
        Animals.................................................18

        i.  Estuarine and marine fish
            acute................................................18

        ii. Estuarine and marine fish
            chronic..............................................19

        iii. Estuarine and marine invertebrates
             acute......................................19

        iv. Whole sediment marine invertebrates
            acute...................................20

        v.  Estuarine and marine invertebrates
            chronic................................. .21

        vi. Estuarine and marine field
            study.............................................\...21

    D.  Toxicity to
        plants.........................................................................21

        i.  Terrestrial and
            semi-aquatic....................................................21

        ii. Aquatic............................................................................22

II\. ENVIRONMENTAL FATE AND TRANSPORT OF
CCA..................................24

III\. ECOLOGICAL RISK
ASSESSMENT........................................................25

> A. Exposure to non-target
> animals............................................................27

i\.
Birds.................................................................................28

ii\.
Mammals...........................................................................29

iii\.
Insects...............................................................................29
B. Exposure and Risk to Non-target Freshwater and Marine/esturarine
organisms....30

> C. Uncertainties in the Risk
> Assessment...................................................\...32

IV. ENDANGERED
    SPECIES.......................................................................33

    V. CONFIRMATORY DATA
    NEEDS............................................................34

    VI\. LABEL
    STATEMENTS..........................................................................35

    VII\.
    REFERENCES.................................................................................
    36

**LIST OF TABLES**

**[Page No.]{.underline}**

Table 1. Avian acute oral Arsenic acid 6

Table 2. Avian Subacute Dietary Toxicity Arsenic acid 7

Table 3. Avian acute oral Chromic acid 8

Table 4. Avian Subacute Dietary Toxicity Chronic acid 8

Table 5. Mammalian Acute Toxicity Arsenic acid 9

Table 6. Mammalian Acute Toxicity Chronic acid 10

Table 7. Mammalian Chronic Toxicity Arsenic acid 11

Table 8. Mammalian Chronic Toxicity Chronic
acid......................................11

Table 9. Non-target Insect Arsenic
acid.....................................................12

Table 10. Freshwater Fish Acute Arsenic
acid...............................................13

Table 11. Freshwater Fish Acute Chronic
acid...............................................13

Table 12. Freshwater Fish Early Life Stage Arsenic
acid...................................14

Table 13. Freshwater Fish Early Life Stage Chronic
acid..................................15

Table 14. Freshwater Invertebrates Acute Toxicity Arsenic
acid..........................15

Table 15. Freshwater Invertebrates Acute Toxicity Chronic
acid.........................16

Table 16. Freshwater Invertebrates Life Cycle Toxicity Arsenic
acid....................17

Table 17. Freshwater Invertebrates Life Cycle Toxicity Chronic
acid....................17

Table 18. Estuarine/Marine Fish Acute Toxicity Arsenic
acid.............................18

Table 19. Estuarine/Marine Fish Acute Toxicity Chronic
acid............................18

Table 20. Estuarine/Marine Invertebrate Acute Arsenic
acid..............................19

Table 21. Estuarine/marine Invertebrate Acute Chronic
acid..............................20

Table 22. Aquatic Plants Acute Arsenic
acid................................................23

Table 23. Aquatic Plants Acute Chronic
acid................................................23

Table 24. Risk Presumption
Categories.......................................................26

Table 25. Metal Concentrations Under CCA
Decks.........................................28

Table 26. RQ Summary Table -- Bobwhite
quail.............................................28

Table 27. RQ Summary Table -- Meadow
vole...............................................29

Table 28. Soil Leaching
Values.................................................................31

Table 29. Soil Runoff
Values....................................................................31

LIST OF APPENDICES

Appendix
A...................................................................................................43

Table
A1................................................................................47

Table
A2................................................................................48

**INORGANIC ARSENICAL WOOD PRESERVATIVES ENVIRONMENTAL RISK RED
CHAPTER**

**Executive Summary**

Inorganic Arsenical wood preservatives are most commonly formulated as
Chromated Copper Arsenate (CCA). This environmental risk assessment
addresses hazard to birds, mammals, plants, insects, fish, and aquatic
invertebrates from two components of inorganic arsenical wood
preservatives; arsenic acid and chromic acid. The third component,
cupric oxide is not included in this risk assessment but will be
addressed in the copper RED (Case Number 4025). Zinc Oxide, the zinc
component of ACZA, has already been assessed by the Agency for the wood
preservative use patterns under the Zinc Salts RED, Case Number 4099,
dated August, 1992. As of January 2004 CCA treated wood can no longer be
used to build residential decks, picnic tables, fences, or other
residential uses. CCA treated dimensional lumber cannot be used to
construct public playgrounds, walkways, boardwalks, decks, docks, hand
rails, or other public surfaces that may come in human contact. CCA can
still be used to treat freshwater or marine piling, bulkheads, and
bracing timbers underneath non-residential docks, decks, and walkways.

The results of the terrestrial risk assessment indicate that the
potential for adverse acute effects to birds and mammals from exposure
to average concentrations of arsenic acid or chromic acid in soil is
low. Average residue levels are not expected to result in chronic
impacts to birds, however, there is slight concern for chronic effects
to mammals based on soil residue levels under existing CCA treated
decks. Average soil concentrations are considered more likely to
represent the exposure level for mobile receptor species such as birds
and mammals than maximum soil concentrations. A quantitative assessment
of the risks to birds and mammals to arsenic acid or chromic acid from
direct contact (feet, feathers, oral) with CCA-treated lumber was not
conducted but is considered to be minimal. Residential decks built after
January 2004 are not expected to leach arsenic or chromium.
Non-residential structures build from CCA treated lumber (bracing,
bulkheads, pilings, support poles) are not expected to pose an adverse
risk to non-target birds or mammalian species due to very limited
surface area exposure and greatly reduced surface area wood volume
(absent dimensional lumber).

Arsenic, chromium, and copper can leach directly from CCA treated
structures installed in water such as pilings, bulkheads, and bracing
lumber for docks and piers. CCA can no longer be used for the treatment
of residential lumber or dimensional lumber for public docks,
playgrounds, or boardwalks. The open literature provides
laboratory-derived leaching study values and some limited field testing.
Leaching rates of arsenic or chromium in available studies are variable
dependent on the test conditions as well as the type of wood, age of the
wood, CCA formulation, and retention levels. Also, arsenic and chromium
are typically found in most soils and sediments in the U.S. at
background levels that approximate those leaching from CCA wood.
Water-column concentrations of these metals in aquatic habitats would
likely be much lower than the values obtained in leaching studies
conducted in small laboratory vessels due to dispersion in the water
body by tidal flow and wave action, and the degree of partitioning into
biota and sediment. Risk quotients (RQ ) were not calculated because of
the high degree of variability in available data and the inability to
predict metals speciation and bioavailability in aquatic environments.
The bioavailabilty of arsenic and chromium is considered to be
relatively constant regardless of CCA wood contribution due to steady
background environmental levels. Aquatic organisms eliminate arsenic and
chromium with little bioaccumulation (see the Environmental Fate
chapter). Published studies on the effects of CCA-treated wood on
aquatic organisms indicate that the metals released from the treated
wood are localized within sediments, typically within 10 meters of the
treated wood. Of the three metals, copper is considered the most toxic
to aquatic organisms. CCA metals are released at higher concentrations
from new wood than from old wood, and benthic levels are higher in
poorly flushed tidal areas close to the treated wood. Leachates from
pilings in well flushed tidal areas do not appear to have adverse
effects on the benthic community. Bethic community impacts may occur
from copper leachate in aquatic areas having high CCA wood usage that
are poorly flushed (Weis et al., 1991; 1995, 1996, 2002, 2004; Brown et
al. 2001).

Some research indicates that making sure that wood is properly
conditioned (complete the fixation reaction) prior to installation in
water; and collection of sawdust during construction/maintenance would
help reduce the impact of CCA metals in the environment (Lebow et al.,
2000, Lebow, 2004).

It is not known if the 3 metals in CCA wood are antagonistic or
synergistic upon exposure to terrestrial or aquatic organisms. The
uptake of arsenic, chromium, and copper by plants; and subsequent
impacts on the food chain are not well understood either.

**Confirmatory Data Needs**

**850.2300 -- Avian reproduction study using chromic acid**

**850.1735 -- Freshwater invertebrate sediment toxicity using arsenic
acid**

**850.1735 - Freshwater invertebrate sediment toxicity using chromic
acid**

**850.1740 - Marine invertebrate sediment toxicity using arsenic acid**

**850.1740 - Marine invertebrate sediment toxicity using chromic acid**

**850.4400 -- *Lemna gibba* aquatic plant toxicity using chromic acid**

**850.5400 - *Skeletonema costatum* aquatic plant toxicity using arsenic
acid**

**850.5400 - *Selenastrum capricornutum* aquatic plant toxicity using
chromic acid**

**850.5400 -- *Anabaena flos-aquae* aquatic plant toxicity using chromic
acid**

**850.5400 -- *Skeletonema costatum* aquatic plant toxicity using
chromic acid**

**850.5400 -- *Navicula pelliculosa* aquatic plant toxicity using
chromic acid**

**850.4225 -- Seedling Emergence terrestrial plant toxicity using
arsenic acid**

**850.4225 - Seedling Emergence terrestrial plant toxicity using chromic
acid**

**850.4250 -- Vegetative Vigor terrestrial plant toxicity using arsenic
acid**

**850.4250 -- Vegetative Vigor terrestrial plant toxicity using chromic
acid**

**Label Statement:**

**Product labels must state: "This product is toxic to birds, mammals,
fish, and aquatic invertebrates."**

**I. Ecological Effects Hazard Assessment**

Primary sources of toxicity endpoints include the Pesticide Ecotoxicity
(oneliner) Database maintained by the U.S. EPA, Office of Prevention,
Pesticides and Toxic Substances/Office of Pesticide Programs (U.S. EPA,
2002a), and the Health Effects Division's Hazard Identification
Assessment Review Committee's (HIARC) report on arsenic and chromium,
which included several toxicity endpoints for mammalian species.

A secondary source for toxicity information is the ECOTOX database
maintained by the U.S. EPA, Office of Research and Development (ORD),
and the National Health and Environmental Effects Research Laboratory's
(NHEERL's) Mid-Continent Ecology Division (U.S. EPA, 2002b). This
database includes both aquatic and terrestrial toxicity studies from
scientifically sound peer-reviewed literature considered supplemental
data.

A review of the open literature was also performed. Ecotoxicity
literature on arsenic and chromium is fairly extensive. Useful studies
referenced in this document are considered scientifically sound and
provide supplemental data which is appropriate for use in a risk
assessment.

**A. Toxicity to Terrestrial Animals**

**i. Birds, Acute and Subacute**

**a. Arsenic acid**

An acute oral toxicity study using the technical grade of the active
ingredient (TGAI) is required to establish the toxicity of arsenic acid
to birds. The preferred test species is either mallard duck (a
waterfowl) or bobwhite quail (an upland game bird). The results of two
studies identified in the pesticide database are presented in the
following table.

# Table 1. Acute Oral Toxicity of Arsenic Acid to Birds

+------------+---------------+------------+-----------------+---------+
| Substance/ | Organism      | Endpoin    | Comments        | Re      |
| % Active   |               | ts/Results |                 | ference |
| Ingredient |               | (mg/kg)    |                 |         |
| (AI)       |               |            |                 |         |
+------------+---------------+------------+-----------------+---------+
| arsenic    | Northern      | LD50 =     | \- core study   | Fl      |
| acid/ 75%  | bobwhite      | 28.9       |                 | etcher, |
|            | (*Colinus     |            | \- organism     | 1987    |
|            | virginianus*) |            | age: 27 wks     | (40     |
|            |               |            |                 | 409013) |
|            |               |            | \- 21 day test  |         |
|            |               |            | duration        |         |
+------------+---------------+------------+-----------------+---------+
| arsenic    | Northern      | LD50 = 46  | \- core study   | C       |
| acid/      | bobwhite      |            |                 | ampbell |
| 76.1%      | (*Colinus     | NOEL =     | \- organism     | et al., |
|            | virginianus*) | 12.5       | age: 18 wks     | 1990    |
|            |               |            |                 |         |
|            |               |            | \- 14 day test  | \(417   |
|            |               |            | duration        | 19201\) |
|            |               |            |                 |         |
|            |               |            | \- NOEL effect: |         |
|            |               |            | weight loss     |         |
+------------+---------------+------------+-----------------+---------+
|            |               |            |                 |         |
+------------+---------------+------------+-----------------+---------+

These results indicate that arsenic acid is highly toxic to avian
species on an acute oral basis. The guideline requirement (71-1/OPPTS
850.2100) is fulfilled (MRID# 40409013, 41719201).

Two subacute dietary studies using the TGAI are required to establish
the toxicity of arsenic acid to birds. The preferred test species are
mallard duck (a waterfowl) and bobwhite quail (an upland gamebird). The
results of three avian subacute dietary tests that were included in the
pesticide database are tabulated below.

**Table 2. Subacute Dietary Toxicity of Arsenic Acid to Birds**

  ------------- --------------- ------------------- ------------------ -----------
  Substance/ %  Organism        Endpoints/Results   Comments           Reference
  Active                        (mg/kg)                                
  Ingredient                                                           
  (AI)                                                                 

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

+------------+---------------+-----------+-----------------+---------+
| arsenic    | Northern      | LC50 =    | \- core study - | EPA     |
| acid/ 75%  | bobwhite      | 168.5     | 8 day test      | 2       |
|            | (*Colinus     |           | duration        | 002a(00 |
|            | virginianus*) |           |                 | 121618) |
+------------+---------------+-----------+-----------------+---------+
| arsenic    | Northern      | LC50 =    | \- core study   | Long et |
| acid/ 76%  | bobwhite      | 432       |                 | al,     |
|            | (*Colinus     |           | \- organism     | 1990    |
|            | virginianus*) | NOEL =    | age: 10d        |         |
|            |               | 15.6      |                 | \(417   |
|            |               |           | \- 8 day test   | 19202\) |
|            |               |           | duration        |         |
|            |               |           |                 |         |
|            |               |           | \- NOEL effect: |         |
|            |               |           | pharmacotoxic   |         |
|            |               |           | signs           |         |
+------------+---------------+-----------+-----------------+---------+
| arsenic    | Fulvous       | LC50 =    | \- core study   | Fl      |
| acid/ 75%  | whistling     | 1145      |                 | etcher, |
|            | duck          |           | \- organism     | 1987    |
|            | (*Dendrocygna | NOEC \<   | age: 9 days     |         |
|            | bicolor*)     | 156       |                 | \(404   |
|            |               |           | \- 8 day test   | 09012\) |
|            |               |           | duration        |         |
|            |               |           |                 |         |
|            |               |           | \- NOEL effect: |         |
|            |               |           | reduced weight  |         |
|            |               |           | gain            |         |
+------------+---------------+-----------+-----------------+---------+

These results indicate that arsenic acid is slightly to highly toxic to
avian species on a subacute dietary basis. The guideline requirement
(71-2/OPPTS 850.2200) is fulfilled (MRID \# 00121618, 41719201,
40409012).

**b. Chromic acid**

An acute oral toxicity study using the TGAI is required to establish the
toxicity of a chromic acid to birds. The preferred test species is
either mallard duck (a waterfowl) or bobwhite quail (an upland
gamebird). The results of two studies are presented in the following
table.

**Table 3 . Acute Oral Toxicity** **of Chromic Acid** **to Birds**

+-----------+--------------+-----------+-----------------+-----------+
| S         | Organism     | Endpoint  | Comments        | Reference |
| ubstance/ |              | s/Results |                 |           |
| % Active  |              | (mg/kg)   |                 |           |
| I         |              |           |                 |           |
| ngredient |              |           |                 |           |
| (AI)      |              |           |                 |           |
+-----------+--------------+-----------+-----------------+-----------+
| chromic   | Northern     | LD50 =    | \- core study   | Hoxter.,  |
| acid/ 57% | bobwhite     | 93.5      |                 | 1990      |
|           | (*Colinus    |           |                 |           |
|           | v            |           |                 | \(4       |
|           | irginianus*) |           |                 | 1621104\) |
+-----------+--------------+-----------+-----------------+-----------+
| chromic   | Northern     | LC50 =    | \- core study   | #         |
| acid/ 57% | bobwhite     | 164       |                 | Hobden, 2 |
|           | (*Colinus    |           | \- organism     | 000 (T15) |
|           | v            | NOEL \>   | age: 38wks      |           |
|           | irginianus*) | 62        |                 |           |
|           |              |           | \- 14 day test  |           |
|           |              |           | duration        |           |
|           |              |           |                 |           |
|           |              |           | \- NOEL effect: |           |
|           |              |           | weight loss     |           |
+-----------+--------------+-----------+-----------------+-----------+

These results indicate that chromic acid is moderately toxic to avian
species on an acute oral basis. The guideline requirement (71-1/OPPTS
850.2100) is fulfilled (MRID# 41621104).

Two subacute dietary studies using the TGAI are required to establish
the toxicity of chromic acid to birds. The preferred test species are
mallard duck (a waterfowl) and bobwhite quail (an upland gamebird). The
results of avian subacute dietary tests are tabulated below.

**Table 4. Subacute Dietary Toxicity of Chromic Acid to Birds**

  ------------ --------------- ------------------- ------------------ ------------
  Substance/ % Organism        Endpoints/Results   Comments           Reference
  Active                       (mg/kg)                                
  Ingredient                                                          
  (AI)                                                                

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

+-----------+--------------+-----------+-----------------+-----------+
| chromic   | Mallard      | LC50 \>   | \- core study - | Hoxter,   |
| acid/ 57% | duck*(Anas   | 5100      | organism age:   | 1990(     |
|           | pla          |           | 10d             | 41621102) |
|           | tyrhynchus)* |           |                 |           |
|           |              |           | \- 8 day test   |           |
|           |              |           | duration        |           |
+-----------+--------------+-----------+-----------------+-----------+
| chromic   | Northern     | LC50 \>   | \- core study   | Ho        |
| acid/ 57% | bobwhite     | 5100      |                 | xter,1990 |
|           | (*Colinus    |           | \- organism     |           |
|           | v            |           | age: 10d        | \(4       |
|           | irginianus*) |           |                 | 1621101\) |
|           |              |           | \- 8 day test   |           |
|           |              |           | duration        |           |
+-----------+--------------+-----------+-----------------+-----------+

These results indicate that chromic acid is practically non-toxic to
avian species on a subacute dietary basis. The guideline requirement
(71-2/OPPTS 850.2200) is fulfilled (MRID \# 41621102, 41621101).

**ii. Birds, Chronic**

Avian reproduction studies using the TGAI may be required for a
pesticide when any of the following conditions are met: (1) birds may be
subject to repeated or continuous exposure to the pesticide, especially
preceding or during the breeding season, (2) the pesticide is stable in
the environment to the extent that potentially toxic amounts may persist
in animal feed, (3) the pesticide is stored or accumulated in plant or
animal tissues, and/or, (4) information derived from mammalian
reproduction studies indicates reproduction in terrestrial vertebrates
may be adversely affected by the anticipated use of the product.

Avian chronic toxicity tests are required for the components of CCA
because birds may be exposed to the compound on treated outdoor
structures (e.g., docks, utility poles, etc.) or to residues from these
structures during daily activities such as feeding, nesting and
grooming. There were no avian chronic toxicity studies for arsenic acid
or chromic acid in the pesticide database. The preliminary risk
assessment indicates that chromic acid may present a chronic toxicity
risk to avian species. The data requirement 850.2300 avian reproduction
study is required as confirmatory data using chromic acid.

A study found in the open literature (Sample et al.,1996) identified a
chronic avian NOAEL of 5.1 mg/kg-day for sodium arsenite (As 3+). This
value was based on the results of a chronic dietary study that evaluated
the effects of sodium arsenite (As 3+) to mallard ducks over a 128-day
study period. Sample et al. (1996) also identified a chromium avian
NOAEL of 1 mg/kg-day. This value was based on the results of a chronic
dietary study that evaluated the effects of chromium (as Cr III) to
black ducks during a ten month study duration.

**iii. Mammals, Acute and Subacute**

Wild mammal testing is required on a case-by-case basis, depending on
the results of lower tier laboratory mammalian studies, intended use
pattern and pertinent environmental fate characteristics. In most cases,
toxicity values for laboratory animals (e.g., rat, mouse) obtained from
the Agency\'s Health Effects Division (HED) substitute for wild mammal
testing.

> **Arsenic acid**

No studies on the acute effects of arsenic acid to wild mammals were
found in the primary or secondary data sources considered for this
assessment; therefore, laboratory mammal acute toxicity endpoints are
used. Acute toxicity values identified for arsenic acid in Chen et al.
(2001) are summarized in the table below.

**Table 5. Mammalian Acute Toxicity of Arsenic Acid**

+-----------+--------------+-----------+-----------------+-----------+
| S         | Organism     | Endpoint  | Comments        | Reference |
| ubstance/ |              | s/Results |                 |           |
| % Active  |              | (mg/kg)   |                 |           |
| I         |              |           |                 |           |
| ngredient |              |           |                 |           |
| (AI)      |              |           |                 |           |
+-----------+--------------+-----------+-----------------+-----------+
| Arsenic   | Laboratory   | LD50 =    | LD50 is the     | #40409001 |
| acid/ 75% | mouse (*Mus  | 150       | mean value for  | as cited  |
|           | musculus*)   |           | male (141mg/kg) | in Chen   |
|           |              |           | and female mice | et al,.   |
|           |              |           | (160mg/kg)      | 2001      |
+-----------+--------------+-----------+-----------------+-----------+
| Arsenic   | Laboratory   | LD50 = 52 | LD50 is the     | \# 26356  |
| acid/ 75% | rat          |           | mean value for  | as cited  |
|           |              |           | male (76mg/kg)  | in Chen   |
|           | *(Rattus     |           | and female rats | et al,.   |
|           | norvegicus)* |           | (37mg/kg)       | 2001      |
+-----------+--------------+-----------+-----------------+-----------+

These results indicate that arsenic acid is moderately to highly toxic
to mammalian species on an acute oral basis. The guideline requirement
(81-1/OPPTS 870.1100) is fulfilled (MRID# 40409001, 26356).

> **Chromic acid**

No studies on the acute effects of chromic acid to wild mammals were
found in the primary or secondary data sources considered for this
assessment; therefore, laboratory mammal acute toxicity endpoints are
used. The results of one acute toxicity study identified in McMahon and
Chen (2001) for chromic acid are provided in the table below.

**Table 6. Mammalian Acute Toxicity of Chromic Acid**

  ------------ --------------- ------------------- ------------------ ------------
  Substance/ % Organism        Endpoints/Results   Comments           Reference
  Active                       (mg/kg)                                
  Ingredient                                                          
  (AI)                                                                

  Chromic      Laboratory rat  LD50 = 52           LD50 is the mean   MRID#
  acid/ 100%   *(Rattus                            value for male (56 434294-01 as
               norvegicus)*                        mg/kg) and female  cited in
                                                   mice (48mg/kg)     McMahon and
                                                                      Chen, 2001
  ------------ --------------- ------------------- ------------------ ------------

This study indicates that chromic acid is highly toxic to mammalian
species on an acute oral basis. The guideline requirement (81-1/OPPTS
870.1100) is fulfilled (MRID# 434294-01).

iv\. Mammals, Chronic

Mammalian reproduction studies using the TGAI may be required for a
pesticide; this requirement is considered in the human toxicology
assessment portion of this RED document. Chronic hazard to wild mammals
from CCA is of concern due to the potential for repeated or continuous
mammalian exposure to CCA components from either direct contact with
treated structures or exposure to residues in soil and/or water from
treated structures.

**a. Arsenic acid**

The Health Effects Division's Hazard Identification Assessment Review
Committee's (HIARC) report on arsenic (McMahon and Chen, 2001) included
several toxicity endpoints for mammalian species. These endpoints have
been provided in the following table.

**Table 7 . Mammalian Chronic Toxicity of Arsenic Acid**

+-----------+------------+-----------+-------------------+-----------+
| S         | Organism   | Endpoint  | Comments          | Reference |
| ubstance/ |            | s/Results |                   |           |
| % Active  |            | (m        |                   |           |
| I         |            | g/kg/day) |                   |           |
| ngredient |            |           |                   |           |
| (AI)      |            |           |                   |           |
+-----------+------------+-----------+-------------------+-----------+
| arsenic   | Laboratory | LOAEL =   | \- gavage         | Nemac     |
| acid/ 75% | mouse      | 64        | administration to | 1968b,    |
|           |            |           | pregnant females  | cited in  |
|           | (*Mus      | NOAEL =   | during day 6-15   | McMahon   |
|           | musculus*) | 32        | of gestation      | and Chen, |
|           |            |           |                   | 2001      |
|           |            |           | \- effects were   |           |
|           |            |           | reduced body      |           |
|           |            |           | weight, increased |           |
|           |            |           | mortality and     |           |
|           |            |           | increased total   |           |
|           |            |           | litter resorption |           |
+-----------+------------+-----------+-------------------+-----------+
| arsenic   | New        | LOAEL = 4 | \- gavage         | Nemac     |
| acid/ 75% | Zealand    |           | administration to | 1988a,    |
|           | White      | NOAEL = 1 | pregnant females  | cited in  |
|           | Rabbit     |           | during day 6-18   | McMahon   |
|           |            |           | of gestation      | and Chen, |
|           |            |           |                   | 2001      |
|           |            |           | \- effects were   |           |
|           |            |           | reduced body      |           |
|           |            |           | weight, increased |           |
|           |            |           | mortality and     |           |
|           |            |           | histological      |           |
|           |            |           | effect to the     |           |
|           |            |           | liver/kidneys     |           |
+-----------+------------+-----------+-------------------+-----------+
| arsenic   | Dog --     | LOAEL =   | \- study duration | Byron et  |
| V/ AI not | Beagle     | 2.4       | -- 2 yrs          | al.,      |
| available |            |           |                   | 1967,     |
|           |            | NOAEL = 1 | \- endpoint was   | cited in  |
|           |            |           | histology effects | ATSDR,    |
|           |            |           | to the liver and  | 1997      |
|           |            |           | anemia            |           |
+-----------+------------+-----------+-------------------+-----------+

These studies indicate that arsenic acid is moderately toxic to
mammalian species on a chronic basis.

b\. Chromic acid

The Health Effects Division's Hazard Identification Assessment Review
Committee's (HIARC) review of chromium (McMahon and Chen, 2001) included
several toxicity endpoints for mammalian species. These endpoints have
been provided in the following table.

**Table 8. Mammalian Chronic Toxicity of Chromic Acid**

+------------+---------------+-----------+-----------------+---------+
| Substance/ | Organism      | Endpoint  | Comments        | Re      |
| % Active   |               | s/Results |                 | ference |
| Ingredient |               | (m        |                 |         |
| (AI)       |               | g/kg/day) |                 |         |
+------------+---------------+-----------+-----------------+---------+
| Chromic    | Laboratory    | LOAEL =   | \- effects      | Tyl,    |
| acid/ 55%  | rabbit        | 0.48      | included        | 1991,   |
|            |               |           | reduced body    | cited   |
|            |               | NOAEL =   | weight,         | in      |
|            |               | 0.12      | increased       | McMahon |
|            |               |           | mortality       | and     |
|            |               |           |                 | Chen,   |
|            |               |           |                 | 2001    |
+------------+---------------+-----------+-----------------+---------+
| Potassium  | Swiss albino  | LOAEL =   | \- effects were | Junaid  |
| d          | mice          | 42.1      | reduced         | et al., |
| ichromate/ |               |           | maternal body   | 1996,   |
| AI not     |               | NOAEL =   | weight,         | cited   |
| available  |               | 22.3      | retarded fetal  | in      |
|            |               |           | development and | McMahon |
|            |               |           | increased fetal | and     |
|            |               |           | resorption \*   | Chen,   |
|            |               |           |                 | 2001    |
+------------+---------------+-----------+-----------------+---------+

> \* The endpoints were based on maternal effects, the fetal effects
> were seen at every dose tested so a developmental NOAEL could not be
> determined.

These studies indicate that chromic acid is moderately to highly toxic
to mammalian species on a chronic basis.

**v. Insects**

A honey bee acute contact study using the TGAI is required for the
active components of CCA because its use as a wood preservative may
result in honey bee exposure. Results of this test for arsenic acid are
tabulated below.

**Table 9. Nontarget Insect Acute Contact Toxicity of Arsenic Acid**

+------------+---------------+-----------+-----------------+---------+
| Substance/ | Organism      | Endpoint  | Comments        | Re      |
| % Active   |               | s/Results |                 | ference |
| Ingredient |               | (ug/bee)  |                 |         |
| (AI)       |               |           |                 |         |
+------------+---------------+-----------+-----------------+---------+
| arsenic    | Honey bee     | LD50 =    | \- core study   | Hoxter, |
| acid/      |               | 7.7       |                 | 1987    |
| 75.1%      | *(Apis        |           |                 |         |
|            | mellifera*)   |           |                 | \(403   |
|            |               |           |                 | 51301\) |
+------------+---------------+-----------+-----------------+---------+

The results indicate that arsenic acid is highly toxic to bees on an
acute contact basis. The guideline requirement (141-1/OPPTS 850.3020) is
fulfilled (MRID #40351301).

There were no honey bee studies identified for chromic acid in the
pesticide database; the guideline requirement (141-1/OPPTS 850.3020) is
not fulfilled for chromic acid. CCA product labels currently restrict
treated wood from use for construction or maintenance of bee hives.
Therefore no further bee toxicity tests are required.

> **vi. Terrestrial Field Testing**

Terrestrial field testing is reserved for the wood preservative use of
CCA pending the outcome of an avian reproduction study and refined risk
assessment.

**B. Toxicity to Freshwater Aquatic Animals**

> **Freshwater Fish, Acute**
>
> **a. Arsenic acid**

Two freshwater fish toxicity studies using the TGAI are required to
establish the toxicity of arsenic acid to fish. The preferred test
species are rainbow trout (a coldwater fish) and bluegill sunfish (a
warmwater fish). Several acute toxicity studies were identified for each
compound of interest in the pesticide database. The results of these
tests are summarized below.

**Table 10. Freshwater Fish Acute Toxicity of Arsenic Acid**

+------------+--------------+------------+------------------+---------+
| Substance/ | Organism     | Endpoin    | Comments         | Re      |
| % Active   |              | ts/Results |                  | ference |
| Ingredient |              | (mg/L)     |                  |         |
| (AI)       |              |            |                  |         |
+------------+--------------+------------+------------------+---------+
| arsenic    | Rainbow      | LC50 = 72  | \- core study    | Le      |
| acid/      | trout        |            |                  | Lievre, |
| 76.1%      |              | NOEL = 3.4 | \- static system | 1990    |
|            | *(           |            |                  |         |
|            | Oncorhynchus |            | \- 96-hr test    | \(416   |
|            | mykiss)*     |            | duration         | 20003\) |
+------------+--------------+------------+------------------+---------+
| arsenic    | Rainbow      | LC50 = 53  | \- supplemental  | EPA     |
| acid/ 75%  | trout        |            | study            | 2002 a  |
|            |              |            |                  | (MRID   |
|            | *(           |            | \- static system | \# not  |
|            | Oncorhynchus |            |                  | re      |
|            | mykiss)*     |            | \- 96-hr test    | ported) |
|            |              |            | duration         |         |
|            |              |            |                  |         |
|            |              |            | \- test organism |         |
|            |              |            | weight 0.57g     |         |
+------------+--------------+------------+------------------+---------+
| arsenic    | Bluegill     | LC50 = 50  | \- core study    | M       |
| acid/      | sunfish      |            |                  | achado, |
| 75.8%      |              | NOEL = 10  | \- flow-through  | 1991    |
|            | *(Lepomis    |            | system           |         |
|            | m            |            |                  | \(419   |
|            | acrochirus)* |            | \- 96-hr test    | 50601\) |
|            |              |            | duration         |         |
|            |              |            |                  |         |
|            |              |            | \- test organism |         |
|            |              |            | weight 1.1g      |         |
+------------+--------------+------------+------------------+---------+
| arsenic    | Bluegill     | LC50 = 54  | \- supplemental  | Sup     |
| acid/ 75%  | sunfish      |            | study            | renant, |
|            |              | NOEL \< 12 |                  | 1987    |
|            | *(Lepomis    |            | \- static system |         |
|            | m            |            |                  | \(404   |
|            | acrochirus)* |            | \- 96-hr test    | 09014\) |
|            |              |            | duration         |         |
|            |              |            |                  |         |
|            |              |            | \- test organism |         |
|            |              |            | weight 1.8g      |         |
+------------+--------------+------------+------------------+---------+

These results indicate that arsenic acid is slightly toxic to freshwater
fish on an acute basis. The guideline requirement (72-/OPPTS 850.1075)
is fulfilled (MRID #41620003, 41950601).

**b. Chromic acid**

Two freshwater fish toxicity studies using the TGAI are required to
establish the toxicity of chromic acid to fish. The preferred test
species are rainbow trout (a coldwater fish) and bluegill sunfish (a
warmwater fish). Two acute toxicity studies were identified for this
compound in the pesticide database. The results of these tests are
summarized below.

**Table 11. Freshwater Fish Acute Toxicity of Chromic Acid**

+-----------+--------------+-----------+-----------------+-----------+
| S         | Organism     | Endpoint  | Comments        | Reference |
| ubstance/ |              | s/Results |                 |           |
| % Active  |              | (mg/L)    |                 |           |
| I         |              |           |                 |           |
| ngredient |              |           |                 |           |
| (AI)      |              |           |                 |           |
+-----------+--------------+-----------+-----------------+-----------+
| Chromic   | Rainbow      | LC50 = 28 | \- core study   | LeLievre, |
| acid/ 57% | trout        |           |                 | 1990      |
|           |              | NOEL =    | \- static       |           |
|           | *(           | 8.6       | system          | \(4       |
|           | Oncorhynchus |           |                 | 1621105\) |
|           | mykiss)*     |           | \- 96-hr test   |           |
|           |              |           | duration        |           |
|           |              |           |                 |           |
|           |              |           | \- test         |           |
|           |              |           | organism weight |           |
|           |              |           | -- 0.5g         |           |
+-----------+--------------+-----------+-----------------+-----------+
| Chromic   | Bluegill     | LC50 = 44 | \- core study   | LeLievre, |
| acid/ 57% | sunfish      |           |                 | 1990      |
|           |              | NOEL = 13 | \- static       |           |
|           | *(Lepomis    |           | system          | \(4       |
|           | m            |           |                 | 1658401\) |
|           | acrochirus)* |           | \- 96-hr test   |           |
|           |              |           | duration        |           |
|           |              |           |                 |           |
|           |              |           | \- test         |           |
|           |              |           | organism weight |           |
|           |              |           | -- 0.5g         |           |
+-----------+--------------+-----------+-----------------+-----------+

These results indicate that chromic acid is slightly to moderately toxic
to freshwater fish on an acute basis. The guideline requirement
(72-/OPPTS 850.1075) is fulfilled (MRID #41621105, 41658401).

> **Freshwater Fish, Chronic**

Fish early life stage tests are required if the product is applied
directly to water or expected to be transported to water from the
intended use site, and when any one or more of the following conditions
apply: (1) if the pesticide is intended for use such that its presence
in water is likely to be continuous or recurrent regardless of toxicity;
(2) if any LC~50~ or EC~50~ value determined in acute toxicity testing
is less than 1 mg/L; or (3) if the estimated concentration in water is
equal to or greater that 0.01 of any EC~50~ or LC~50~ determined in
acute toxicity testing; (4) if the actual or estimated environmental
concentration in water resulting from use is less than 0.01 of any
EC~50~ or LC~50~ determined in acute toxicity testing and any of the
following conditions exist: (a) studies of other organisms indicate the
reproductive physiology of fish and /or invertebrates may be affected;
(b) physicochemical properties indicate cumulative effects; (c) the
pesticide is persistent in water (e.g. half-life in water greater than 4
days). The preferred test species is fathead minnow (*Pimephales
promelas*), but other species may be used. Fish early life-stage testing
is required due to the likelihood of continuous exposure from
CCA-treated structures in aquatic habitats. Freshwater and
marine/estuarine fish are comparably sensitive to arsenic acid and
chromic acid on an acute basis, so early life-stage testing on either
type of fish is sufficient to satisfy guideline requirements. Early
life-stage testing was submitted to the agency for arsenic acid and
chromic acid using freshwater species; that data is summarized below.

**a. Arsenic acid**

**Table 12. Freshwater Fish Early Life Stage Toxicity of Arsenic Acid**

+-----------+--------------+-----------+-----------------+-----------+
| S         | Organism     | Endpoint  | Comments        | Reference |
| ubstance/ |              | s/Results |                 |           |
| % Active  |              | (mg/L)    |                 |           |
| I         |              |           |                 |           |
| ngredient |              |           |                 |           |
| (AI)      |              |           |                 |           |
+-----------+--------------+-----------+-----------------+-----------+
| Arsenic   | Fathead      | LOAEC =   | \- core study   | Machado,  |
| acid/     | minnow       | 1.9       |                 | 1991      |
| 76.1%     |              |           | \- flow-through |           |
|           | *(Pimphales  | NOAEC =   | system          | \(4       |
|           | promelas)*   | 0.97      |                 | 1802201\) |
|           |              |           | \- 35 day test  |           |
|           |              |           | duration        |           |
|           |              |           |                 |           |
|           |              |           | \- endpoint is  |           |
|           |              |           | larval survival |           |
+-----------+--------------+-----------+-----------------+-----------+

The results of this study indicate that arsenic acid affects fish larval
survival at levels greater than 0.97 ppm. The guideline requirement
(72-4/OPPTS 850.1400) is fulfilled (#41802201).

**b. Chromic acid**

**Table 13. Freshwater Fish Early Life Stage Toxicity of Chromic Acid**

+-----------+--------------+-----------+-----------------+-----------+
| S         | Organism     | Endpoint  | Comments        | Reference |
| ubstance/ |              | s/Results |                 |           |
| % Active  |              | (mg/L)    |                 |           |
| I         |              |           |                 |           |
| ngredient |              |           |                 |           |
| (AI)      |              |           |                 |           |
+-----------+--------------+-----------+-----------------+-----------+
| chromic   | Fathead      | LOAEC =   | \- core study   | Machado,  |
| acid/ 57% | minnow       | 8.2       |                 | 1991      |
|           |              |           | \- flow-through |           |
|           | *(Pimphales  | NOAEC =   | system          | \(4       |
|           | promelas)*   | 4.0       |                 | 1974901\) |
|           |              |           | \- 35 day test  |           |
|           |              |           | duration        |           |
|           |              |           |                 |           |
|           |              |           | \- endpoint is  |           |
|           |              |           | larval growth   |           |
+-----------+--------------+-----------+-----------------+-----------+

This result indicates that chromic acid causes larval growth effects at
levels above 4.0 ppm. The guideline requirement (72-4/OPPTS 850.1400)
is fulfilled (#41974901).

**iii. Freshwater Invertebrates, Acute**

A freshwater aquatic invertebrate toxicity test using the TGAI is
required to establish the toxicity of the components of CCA to aquatic
invertebrates. The preferred test species is *Daphnia magna*. Results of
this test for arsenic acid and chromic acid are provided in the tables
below.

**Table 14. Acute Toxicity of Arsenic Acid to Freshwater Invertebrates**

+------------+---------------+-----------+-----------------+---------+
| Substance/ | Organism      | Endpoint  | Comments        | Re      |
| % Active   |               | s/Results |                 | ference |
| Ingredient |               |           |                 |         |
| (AI)       |               | (mg/L)    |                 |         |
+------------+---------------+-----------+-----------------+---------+
| arsenic    | Water flea    | EC50 = 15 | \- core study   | Le      |
| acid/      | *(Daphnia     |           |                 | Lievre, |
| 76.1%      | magna)*       | NOEL =    | \- static       | 1990    |
|            |               | 2.6       | system          |         |
|            |               |           |                 | \(416   |
|            |               |           | \- 48-hour test | 20001\) |
|            |               |           | duration        |         |
|            |               |           |                 |         |
|            |               |           | \- endpoint is  |         |
|            |               |           | immobilization  |         |
+------------+---------------+-----------+-----------------+---------+

This study indicates that arsenic acid is slightly toxic to aquatic
invertebrates on an acute basis. The guideline requirement (72-2) is
fulfilled (41620001).

**Table 15. Acute Toxicity of Chromic Acid to Freshwater Invertebrates**

+--------------+----------+------------+--------------------+---------+
| Substance/ % | Organism | Endpoin    | Comments           | Re      |
| Active       |          | ts/Results |                    | ference |
| Ingredient   |          |            |                    |         |
| (AI)         |          | (mg/L )    |                    |         |
+--------------+----------+------------+--------------------+---------+
| chromic      | Water    | EC50 =     | \- core study      | Le      |
| acid/ 57%    | flea     | 0.76       |                    | Lievre, |
|              |          |            | \- static system   | 1990    |
|              | *        | NOEL \<    |                    |         |
|              | (Daphnia | 0.35       | \- 48-hour test    | \(416   |
|              | magna)*  |            | duration           | 21103\) |
|              |          |            |                    |         |
|              |          |            | \- endpoint is     |         |
|              |          |            | immobilization     |         |
+--------------+----------+------------+--------------------+---------+

This study indicates that chromic acid is highly toxic to aquatic
invertebrates on an acute basis. The guideline requirement (72-2) is
fulfilled (MRID# 416211043).

**iv. Whole Sediment Acute Invertebrate, Freshwater**

Whole sediment acute invertebrate, freshwater studies (1) may be
required when treated wood will be used in the aquatic environment or
use in aquatic sites is not prohibited: (2) may be required on a
case-by-case basis depending on the results of lower tier ecological
studies (e.g., active ingredient or end-use products are highly toxic to
aquatic organisms) and/or pertinent environmental characteristics (e.g.,
Kow is greater than or equal to ([\>]{.underline}) 1,000 or hydrolysis
half-life is greater than (\>) 5 days); and (3) required for
organic-based compounds with a Koc (organic carbon coefficient) greater
than (\>) 1,000 and solubility is less than, or equal to,
([\<]{.underline}) 0.1 mg/ml. The components of CCA meet the above
environmental fate criteria for whole sediment toxicity testing since
CCA-treated wood is used in aquatic environments and available data
regarding the acute toxicity of the components of CCA indicates high
toxicity to freshwater invertebrates from chromic acid. Because no data
on this topic could be located, the risk to invertebrates from exposure
to CCA- contaminated sediment cannot be addressed at this time. Two
whole sediment acute tests are required as confirmatory data (850.1735),
one using arsenic acid and one using chromic acid.

**v. Freshwater Invertebrate, Chronic**

A freshwater invertebrate life-cycle test using the TGAI is required for
a pesticide when it is used in the aquatic environment or use in aquatic
sites is not prohibited and when any of the following conditions apply:
(1) if any LC~50~ or EC~50~ value determined in acute toxicity testing
is less than 1 mg/L; (2) if the estimated environmental concentration is
water is greater than or equal to ([\>]{.underline}) 0.01 of any EC~50~
or LC~50~ determined in acute toxicity testing; (3) if the actual or
estimated environmental concentration in water is less than 0.01 of any
EC~50~ or LC~50~ determined in acute toxicity testing and any of the
following conditions exist: (a) studies of other organisms indicate the
reproductive physiology of fish/invertebrates may be affected; (b)
physicochemical properties indicate cumulative effects may occur and/or;
(c) the pesticide is persistent in water. The preferred test species is
*Daphnia magna*.

Aquatic invertebrate life-cycle testing is required for the components
of CCA since CCA-treated lumber will be used to construct structures in
aquatic environments (e.g., pier, piling, or dock uses). The results of
these tests for arsenic acid and chromic acid are provided below.

**Table 16. Freshwater Aquatic Invertebrate Life-Cycle Toxicity of**
**Arsenic Acid**

+------------+---------------+-----------+-----------------+---------+
| Substance/ | Organism      | Endpoint  | Comments        | Re      |
| % Active   |               | s/Results |                 | ference |
| Ingredient |               |           |                 |         |
| (AI)       |               | (ug/L )   |                 |         |
+------------+---------------+-----------+-----------------+---------+
| arsenic    | Water flea    | LOEC = 38 | \- supplemental | Mc      |
| acid/      | *(Daphnia     |           | study           | Namara, |
| 76.1%      | magna)*       | NOAEC =   |                 | 1991    |
|            |               | 20        | \- flow-through |         |
|            |               |           | system          | \(420   |
|            |               |           |                 | 01601\) |
|            |               |           | \- 21day test   |         |
|            |               |           | duration        |         |
|            |               |           |                 |         |
|            |               |           | \- NOAEC        |         |
|            |               |           | effect - growth |         |
+------------+---------------+-----------+-----------------+---------+

These results indicate that arsenic acid impacts the growth of aquatic
invertebrates at levels greater than 20 ppb. The guideline requirement
(72-4b) is fulfilled (MRID #42001601).

**Table 17. Freshwater Aquatic Invertebrate Life-Cycle Toxicity of**
**Chromic Acid**

+------------+---------------+-----------+-----------------+---------+
| Substance/ | Organism      | Endpoint  | Comments        | Re      |
| % Active   |               | s/Results |                 | ference |
| Ingredient |               |           |                 |         |
| (AI)       |               | (ug/L )   |                 |         |
+------------+---------------+-----------+-----------------+---------+
| Chromic    | Water flea    | LOEC \<   | \- core study   | Mc      |
| acid/ 57%  | *(Daphnia     | 8.6       |                 | Namara, |
|            | magna)*       |           | \- flow-through | 1991    |
|            |               | NOAEC \<  | system          |         |
|            |               | 2.6       |                 | \(418   |
|            |               |           | \- 21day test   | 81501\) |
|            |               |           | duration        |         |
|            |               |           |                 |         |
|            |               |           | \- NOAEC effect |         |
|            |               |           | -reproduction   |         |
+------------+---------------+-----------+-----------------+---------+

These results indicate that chromic acid impacts the reproduction of
aquatic invertebrates at levels greater than 2.6 ppb. The guideline
requirement (72-4b) is fulfilled (MRID#41881501).

**vi. Freshwater Field Studies**

Simulated or actual field testing may be required on a case-by-case
basis depending on the results of lower tier ecological studies (e.g.,
active ingredient or end-use products are highly toxic to aquatic
organisms) and/or pertinent environmental characteristics (e.g., Kow is
greater than or equal to ([\>]{.underline}) 1,000 or hydrolysis
half-life is greater than (\>) 5 days). Certain components of CCA meet
these environmental fate criteria, however, an aquatic field study
(850.1950) is deferred pending the agency review of copper.

> **vii. Freshwater Organism Toxicity Data from Published Scientific
> Literature**

Several studies in the open literature have evaluated the effects of CCA
components to aquatic organisms. Scientific literature indicates that
aquatic organisms may be adversely affected by the components of CCA if
they are exposed to very high concentrations of the metals. For example,
benthic organisms that occur near CCA-treated structures such as docks
and bulkheads are likely to be exposed to very high metal concentrations
(Weis et al., 1991). Actual concentrations of arsenic and chromium in
surface water and sediment as the result of leaching from CCA-structures
are dependent on many factors such as size of the waterbody, flow
patterns (e.g., current, tides), physiochemical properties of the
surface water and sediment, and characteristics of the treated structure
(e.g., size, wood type, structural age).

**C. Toxicity to Estuarine and Marine Animals**

**i. Estuarine and Marine Fish, Acute**

Acute toxicity testing with estuarine/marine fish using the TGAI is
required for a pesticide when the end-use product is intended for direct
application to the marine/estuarine environment or the active ingredient
is expected to reach this environment because of its use in coastal
counties. The preferred test species is sheepshead minnow.
Marine/estuarine acute testing was required for the components of CCA
due to its use as a wood preservative for lumber used to construct
docks, piers and pilings. Results of these tests are tabulated below for
arsenic acid and chromic acid.

**Table 18. Acute Toxicity of Arsenic Acid to Estuarine/Marine Fish**

+------------+---------------+------------+-----------------+---------+
| Substance/ | Organism      | Endpoin    | Comments        | Re      |
| % Active   |               | ts/Results |                 | ference |
| Ingredient |               |            |                 |         |
| (AI)       |               | (mg/L )    |                 |         |
+------------+---------------+------------+-----------------+---------+
| arsenic    | Sheepshead    | LC50 = 28  | \- core study   | 4       |
| acid/      | minnow        |            |                 | 1620004 |
| 76.1%      |               | NOEL = 13  | \- static       |         |
|            | *(Cyprinodon  |            | system          | Le      |
|            | variegatus)*  |            |                 | Lievre, |
|            |               |            | \- 96 hour test | 1990    |
|            |               |            | duration        |         |
+------------+---------------+------------+-----------------+---------+

This study indicates that arsenic acid is moderately toxic to
estuarine/marine fish on an acute basis. The guideline requirement
(72-3a) is fulfilled (MRID #41620004).

**Table 19. Acute Toxicity of Chromic Acid to Estuarine/Marine Fish**

+------------+---------------+------------+----------------+----------+
| Substance/ | Organism      | Endpoin    | Comments       | R        |
| % Active   |               | ts/Results |                | eference |
| Ingredient |               |            |                |          |
| (AI)       |               | (mg/L)     |                |          |
+------------+---------------+------------+----------------+----------+
| chromic    | Sheepshead    | LC50 = 39  | \- core study  | 41703601 |
| acid/ 57%  | minnow        |            |                |          |
|            |               | NOEL = 20  | \- static      | LeLie    |
|            | *(Cyprinodon  |            | system         | vre/1990 |
|            | variegatus)*  |            |                |          |
|            |               |            | \- 96 hour     |          |
|            |               |            | test duration  |          |
+------------+---------------+------------+----------------+----------+

The results indicate that chromic acid is moderately toxic to
estuarine/marine fish on an acute basis. The guideline requirement
(72-3a) is fulfilled (MRID #41703601).

**ii. Estuarine and Marine Fish, Chronic**

Fish early life-stage testing using the TGAI is required for wood
preservatives if the product will be used to treat wood used in an
aquatic habitat, such as piers, pilings, and docks. Early life-stage
toxicity data are required on the more sensitive type of fish,
freshwater or estuarine/marine. Based on review of the acute toxicity
data, freshwater and marine/estuarine fish appear to be comparably
sensitive to arsenic acid and chromic acid. Since acceptable fish early
life-stage data were available for the freshwater species fathead
minnow, fish early life-stage testing with a marine/estuarine fish is
not required for either arsenic acid or chromic acid.

**iii. Estuarine and Marine Invertebrates, Acute**

Acute toxicity testing with estuarine/marine invertebrates using the
TGAI is required for a pesticide when the end-use product is intended
for direct application to the marine/estuarine environment or the active
ingredient is expected to reach this environment because of its use in
coastal counties. The preferred test species are mysid shrimp and
eastern oyster. Estuarine/marine invertebrate testing was required for
the components of CCA due to its use as a wood preservative for lumber
used to construct docks, piers and pilings in coastal waters. See
results of this test in Table 20 below.

**Table 20. Acute Toxicity of Arsenic Acid to Estuarine/Marine
Invertebrates\***

+------------+---------------+------------+---------------+-----------+
| Substance/ | Organism      | Endpoin    | Comments      | Reference |
| % Active   |               | ts/Results |               |           |
| Ingredient |               |            |               |           |
| (AI)       |               | (mg/L )    |               |           |
+------------+---------------+------------+---------------+-----------+

+------------+---------------+------------+---------------+-----------+
| arsenic    | Mysid         | LC50 = 2   | \- core       | 41620002  |
| acid/      |               |            | study- static |           |
| 76.1%      | (*Mysidopsis  | NOEL \<    | system        | LeLi      |
|            | bahia*)       | 0.32       |               | evre/1990 |
|            |               |            | \- 96 hour    |           |
|            |               |            | test duration |           |
+------------+---------------+------------+---------------+-----------+

> \* Note: Oyster testing was waived for arsenic acid

The results indicate that arsenic acid is moderately toxic to the Mysid
shrimp on an acute basis. The guideline requirement 72-3b is waived, and
the guideline requirement 72-3c is fulfilled (MRID #4160002).

**Table 21. Acute Toxicity of Chromic Acid to Estuarine/Marine
Invertebrates\***

+------------+------------+--------------+-----------------+---------+
| Substance/ | Organism   | Endpo        | Comments        | Re      |
| % Active   |            | ints/Results |                 | ference |
| Ingredient |            |              |                 |         |
| (AI)       |            | (mg/L )      |                 |         |
+------------+------------+--------------+-----------------+---------+
| chromic    | Mysid      | LC50 = 5.9   | \- core study   | 4       |
| acid/ 57%  |            |              |                 | 1703602 |
|            | (*         | NOEL = 2.3   | \- static       |         |
|            | Mysidopsis |              | system          | Le      |
|            | bahia*)    |              |                 | Lievre, |
|            |            |              | \- 96 hour test | 1990    |
|            |            |              | duration        |         |
+------------+------------+--------------+-----------------+---------+

> \* Note: Oyster testing was waived for chromic acid

The results indicate that chromic acid is moderately toxic to the Mysid
shrimp on an acute basis. The guideline requirement 72-3b is waived, and
the guideline requirement 72-3c is fulfilled (MRID #41703602).

**iv. Whole Sediment Acute Invertebrate, Marine**

Whole sediment acute invertebrate, marine studies are required for uses
in estuarine/marine environments and may be required when (1) treated
wood will be used in the aquatic environment or use in aquatic sites is
not prohibited; (2) may be required on a case-by-case basis depending on
the results of lower tier ecological studies (e.g., active ingredient or
end-use products are highly toxic to aquatic organisms) and/or pertinent
environmental characteristics (e.g., Kow is greater than or equal to
([\>]{.underline}) 1,000 or hydrolysis half-life is greater than (\>) 5
days); and (3) required for organic-based compounds with a Koc (organic
carbon coefficient) greater that (\>) 1,000 and solubility is less than
or equal to ([\<]{.underline}) 0.1 mg/l.

Several published studies have evaluated the effects of CCA to marine
and estuarine sediment-dwelling organisms. Weis et al. (1998) studied
five CCA-treated wood bulkheads of different ages in estuaries from New
York to South Carolina. These authors concluded that metals leached from
the treated wood and accumulated in the fine-grain fractions of nearby
sediments. Benthic community species richness, diversity and biomass
were reduced at sample stations one meter from the bulkheads, generally
returning to background characteristics at a distance of 10 meters from
the bulkheads. Confirmatory marine soil invertebrate study 850.1740 is
required.

**v. Estuarine and Marine Invertebrate, Chronic**

Aquatic invertebrate life-cycle testing using the TGAI is required for
wood preservatives if the product will be used to treat wood used in an
aquatic habitat, such as piers, pilings, and docks. Data are required on
the more sensitive type of invertebrate, freshwater or estuarine/marine.
Acute data show that freshwater and marine/estuarine invertebrates are
comparably sensitive to arsenic acid, and that freshwater invertebrates
are more sensitive than marine/estuarine invertebrates to chromic acid.
Since acceptable aquatic invertebrate life-cycle data was submitted for
the freshwater species *Daphnia magna*, testing with a marine/estuarine
invertebrate is not required for arsenic acid or chromic acid.

**vi. Estuarine and Marine Field Studies**

Simulated or actual field testing may be required on a case-by-case
basis depending on the results of lower tier ecological studies (e.g.,
active ingredient or end-use products are highly toxic to aquatic
organisms) and/or pertinent environmental characteristics (e.g., Kow is
greater than or equal to ([\>]{.underline}) 1,000 or hydrolysis
half-life is greater than (\>) 5 days). Certain components of CCA meet
these environmental fate criteria, however, an aquatic field study in
the estuarine/marine environment (850.1950) is deferred pending the
agency review of copper.

**D. Toxicity to Plants**

**i. Terrestrial / Semi-aquatic**

Terrestrial plant tests, including seedling emergence (123-1/OPPTS
850.4225) and vegetative vigor testing (123-1/OPPTS 850.4250), are
required for wood preservatives in cases where the treated wood will be
used in the aquatic environment (e.g., bulkheads, piers, pilings). Only
one plant species, rice (*Oryza sativa*), must be tested. CCA meets the
criteria for testing, since CCA-treated wood can be used in the aquatic
environment.

Several studies in the open literature have evaluated the effects of CCA
components to various terrestrial plant species. The results of these
studies are summarized below.

**a. Arsenic**

Arsenic is taken up actively by plant roots, with arsenate being more
easily absorbed than arsenite. Because arsenic is chemically similar to
phosphorus, it is translocated in the plant in a similar manner and is
able to replace phosphorus in many cell reactions. Mechanisms of arsenic
(V) toxicity to terrestrial plants include interrupted phosphorylation
and adverse effects to enzyme systems (Efroymson et al. 1997).

In review of the literature, one study evaluated the toxicity of arsenic
(V) to corn grown from seed for 4 weeks in a loamy sand with a pH of
7.1. Results of the study indicated that corn fresh weight reductions
rose from less than 10% with the addition of 10 ppm arsenic to more than
65% with the addition of 100 ppm arsenic (Efroymson et al. 1997).
Another study assessed the toxicity of arsenic (III) and arsenic (V)
added to soil on the yield of ryegrass and barley grown from seed for 1
year in a greenhouse. According to the study, there was a significant
reduction in the yield of ryegrass (63%) following the addition of 250
ppm arsenic (V) to the soil (Efroymson et al., 1997). It should be noted
that rice and legumes appear to be more sensitive to arsenic than other
plants. Symptoms include wilting of new-cycle leaves, followed by
retardation of root and top growth, and leaf necrosis.

**b. Chromium**

Chromium VI is more soluble and available to plants than chromium III
and is therefore considered to be the more toxic form. Chromium that is
taken up by plants generally remains in the roots because of the many
binding sites in the cell wall capable of binding chromium ions.
Symptoms of chromium toxicity in plants include stunted growth, poorly
developed roots and leaf curling. Chromium may interfere with carbon
(C), nitrogen (N), phosphorus (P) and iron (Fe) metabolism and enzyme
reactions (Efroymson et al., 1997).

One study investigated the effect of chromium (VI) on soybean seedlings
grown three days in a loam soil. The study found that fresh shoot weight
was reduced 30% following the addition of 30ppm chromium, while 10 ppm
chromium had no observed effect. Another study calculated EC50
concentrations for effects of chromium (VI) on lettuce, tomato and oats
grown in a growth chamber from seed for 14 days. Test plants grown in a
loam soil had EC50 values ranging from 1.8 ppm (in lettuce) to 7.4 ppm
(in oats). Test plants grown in a humic sand soil appeared to be
relatively less sensitive to chromium (VI) exposure with EC50 values
ranging from \> 11 ppm (in lettuce) to 31 ppm (in oats), respectively
(Efroymson et al.,1997).

Rice dose-response toxicity tests 850.4225 (seedling emergence) and
850.4250 (vegetative vigor) are required as confirmatory data for both
chromic acid and arsenic acid.

A non-target plant terrestrial field test 850.4300 is reserved pending
the Agency review of copper.

**ii. Aquatic Plants**

Aquatic plant testing is required for wood preservatives if they are
used to treat wood intended for use in aquatic environments (e.g., pier,
piling, or dock uses). Testing is conducted with five aquatic plant
species; one species of aquatic floating macrophyte (*Lemna gibba*), one
green algae species (*Skeletonema costatum*), one blue-green
cyanobacteria (*Anabaena flos-aquae*), one marine diatom (*Selenastrum
capricornutum*), and one freshwater diatom *(Navicula pelliculosa*). CCA
meets the criteria for testing, since CCA-treated wood can be used in
the aquatic environment. The results of the submitted data for this
requirement are listed in Table 22 below.

**Table 22. Acute Toxicity of Arsenic Acid to Aquatic Plants**

+--------------+--------------+--------------+--------------+---------+
| Substance/ % | Organism     | Endpo        | Comments     | Re      |
| Active       |              | ints/Results |              | ference |
| Ingredient   |              |              |              |         |
| (AI)         |              | (mg/L )      |              |         |
+--------------+--------------+--------------+--------------+---------+
| arsenic acid | Duckweed     | EC50 \> 9.8  | \- core      | EPA     |
| / 75.8%      | (Lemna       | ppm          | study        | 2002a   |
|              | gibba)       |              |              | (42     |
|              |              | NOEL \< 9.8  | \- static    | 290901) |
|              |              | ppm          | system       |         |
|              |              |              |              |         |
|              |              |              | \- 14 day    |         |
|              |              |              | test         |         |
|              |              |              | duration     |         |
+--------------+--------------+--------------+--------------+---------+
| arsenic acid | Green alga   | EC50 = 0.038 | \- core      | E       |
| / 75.8%      | (Selenastrum | ppm          | study        | PA2002a |
|              | ca           |              |              |         |
|              | pricornutum) | NOEL =0.005  | \- static    | \(422   |
|              |              | ppm          | system       | 90902\) |
|              |              |              |              |         |
|              |              |              | \- 5 day     |         |
|              |              |              | test         |         |
|              |              |              | duration     |         |
+--------------+--------------+--------------+--------------+---------+
| arsenic acid | Freshwater   | EC50 = 1.4   | \-           | E       |
| / 75.8%      | diatom       | ppm          | supplemental | PA2002a |
|              | (*Navicula   |              | study        |         |
|              | p            | NOEL \< 0.66 |              | \(422   |
|              | elliculosa*) | ppm          | \- static    | 90903\) |
|              |              |              | system       |         |
|              |              |              |              |         |
|              |              |              | \- 5 day     |         |
|              |              |              | test         |         |
|              |              |              | duration     |         |
+--------------+--------------+--------------+--------------+---------+
| arsenic acid | Marine       | EC50 =       | \-           | EPA     |
| / 75.8%      | diatom       | 0.0092 ppm   | supplemental | 2002a   |
|              | (            |              | study        | (42     |
|              | *Skeletonema | NOEL \<      |              | 278801) |
|              | costatum*)   | 0.007 ppm    | \- static    |         |
|              |              |              | system       |         |
|              |              |              |              |         |
|              |              |              | \- 5 day     |         |
|              |              |              | test         |         |
|              |              |              | duration     |         |
+--------------+--------------+--------------+--------------+---------+
| arsenic acid | Bluegreen    | EC50 \> 2.4  | \-           | E       |
| / 75.8%      | alga         | ppm          | supplemental | PA2002a |
|              | (*Anabaena   |              | study        |         |
|              | flos-aquae*) | NOEL = 0.28  |              | \(422   |
|              |              | ppm          | \- static    | 78802\) |
|              |              |              | system       |         |
|              |              |              |              |         |
|              |              |              | \- 5 day     |         |
|              |              |              | test         |         |
|              |              |              | duration     |         |
+--------------+--------------+--------------+--------------+---------+

The results indicate that arsenic acid is moderately toxic to very
highly toxic to aquatic plants. The guideline 850.5400 is partially
fulfilled. The marine diatom, *Skeletonema costatum* appears to be
substantially more sensitive to arsenic acid than the other species
tested. Therefore, this test must be repeated to confirm study results.
The blue-green Anabaena flos-aquae study is waived.

Aquatic plant toxicity data have not been submitted for chromic acid.
Two studies were identified in the ECOTOX database that evaluated the
effects of chromic acid to aquatic plants. Results of these studies are
summarized in the Table 23 below:

**Table 23. Acute Toxicity of Chromic Acid to Aquatic Plants**

+--------------+--------------+---------------+-------------+---------+
| Substance/ % | Organism     | Endp          | Comments    | Re      |
| Active       |              | oints/Results |             | ference |
| Ingredient   |              |               |             |         |
| (AI)         |              | (mg/L )       |             |         |
+--------------+--------------+---------------+-------------+---------+
| chromic acid | Green alga   | EC50 = 0.2    | \-          | EPA,    |
| / AI not     | (Selenastrum | ppm           | s           | 2002b,  |
| available    | ca           |               | upplemental | (ref    |
|              | pricornutum) |               |             | #3690)  |
|              |              |               | \- static   |         |
|              |              |               | system      |         |
|              |              |               |             |         |
|              |              |               | \- 120 hour |         |
|              |              |               | test        |         |
|              |              |               | duration    |         |
|              |              |               |             |         |
|              |              |               | \- endpoint |         |
|              |              |               | is          |         |
|              |              |               | population  |         |
|              |              |               | growth      |         |
+--------------+--------------+---------------+-------------+---------+

+--------------+--------------+---------------+-------------+---------+
| chromic      | Marine       | EC50 = 14.7   | \-          | EPA,    |
| acid,        | diatom       | ppm           | s           | 2002b   |
| dipotassium  | (            |               | upplemental | (ref    |
| salt / AI    | *Skeletonema |               |             | #2233)  |
| not          | costatum*)   |               | \- static   |         |
| available    |              |               | system      |         |
|              |              |               |             |         |
|              |              |               | \- 5 day    |         |
|              |              |               | test        |         |
|              |              |               | duration-   |         |
|              |              |               | endpoint is |         |
|              |              |               | population  |         |
|              |              |               | growth      |         |
+--------------+--------------+---------------+-------------+---------+

The results indicate that chromic acid is moderately to highly toxic to
aquatic plants. The guideline studies 850.4400 (*Lemna gibba*) and
850.5400 (*Selenastrum capricornutum, Anabaena flos-aquae, Skeletonema
costatum,* and *Navicula pelliculosa*) are not fulfilled. The full set
of aquatic plant toxicity studies for chromic acid are required as
confirmatory data.

A non-target aquatic plant field study is reserved pending the Agency
review of copper.

**II. [Environmental Fate and Transport Assessment of Chromated Copper
Arsenate (CCA)]{.underline} (from the Environmental Fate Chapter)**

Copper, chromium and arsenic as oxides are the active ingredients of the
water-borne wood preservative of chromated copper arsenate (CCA). There
are a number of commercially available wood preservatives which contain
these three metals. These products are identified as CCA-A, CCA-B,
CCA-C. This assessment is about CCA-C. The major difference between
these CCA products is the ratio of the metal oxides in the formulations.
CCA is primarily used as a pressure treatment wood preservative for
utility poles. Most exposure from the use of this wood preservative
occurs in three environmental compartments: soil /sediments, surface and
ground water and bioaccumulation in the aquatic and benthic organisms.

The leaching of these metals (Copper, Chromium, and arsenic) into water
from CCA is widely investigated and both the laboratory and field
studies, though contradictory in results and interpretations, generally
indicate that leaching of the metals is a function of pH, salinity
(fresh water, sea water, estuaries, natural and synthetic, sterile
buffered water), temperature, moisture content of the treated wood, wood
type, and wood texture. Results form a number of studies indicate that
most of the leaching takes place in the first few days after the
application. Most of these studies have shown that the extent and rate
of leaching is: Cu\>As\> Cr. Available studies were conducted under
different conditions and the exact concentrations of CCA solution
absorbed by wood (e.g. utility poles) are not known. Sorption constants
of these metals are high for various soils. Leaching of the metals into
soils also depends on the pH of the soil, type and texture of the soils,
organic content of the soils; however, studies on sorption into soils
from utility poles have shown that the release of metals into
soils/sediments from the base of treated wood, decks or utility poles or
from the pressure treatment facilities, do not show a high degree of
downward or ground level migration. In most cases, after migration of
the metals a few meters down into soil, these metals attain the
background level concentration of soil.

Bioaccumulation studies indicate that copper, as Cu(II), released from
CCA has a greater tendency to bioaccumulate in various aquatic and
benthic organisms than the other two metals. Chromium is released into
water and soil as Cr(III), but the concentration of Cr(III) is least of
the three metals, partly due to the fixation process in the wood
structure. Arsenic is leached into soil and water as As(V). However, few
open literature studies report short depuration rates.

In general, the metals in water exist as hydrated species (coordinated
with water), or hydroxy species or the metal is bound to inorganic
anions like FeF~6~^-3^, or bonded to organic ligands to form metal
complexes or as organometallics (contains C-Metal bonds). Fate and
transport processes, and interaction with aquatic and benthic organisms
by these chemical species will vary from one of type of organism to
another. The metals from CCA when released into water systems usually
attain background concentrations. In view of the fact that the metals
attain background level concentrations in soil and water, and the
tendency of the metals to speciate, it is hard to ascertain the source
of contamination in water and soil. Considering absence of comprehensive
ground water monitoring relative to the leaching of metals from CCA into
soils and water, it appears no significant possibility exists for ground
water contamination in areas where utility poles have been placed and
where decks have been built.

**III. Ecological Risk Assessment**

Risk characterization integrates the results of the exposure and
ecotoxicity data to evaluate the likelihood of adverse ecological
effects. The means of this integration is called the quotient method.
Risk quotients (RQs) are calculated by dividing exposure estimates by
acute and chronic ecotoxicity values.

RQ = EXPOSURE/TOXICITY

RQs are then compared to OPP\'s levels of concern (LOCs). These LOCs are
used by OPP to analyze potential risk to nontarget organisms and the
need to consider regulatory action. The criteria indicate that a
pesticide used as directed has the potential to cause adverse effects on
nontarget organisms. LOCs currently address the following risk
presumption categories: (1) **acute** \-- potential for acute risk to
non-target organisms which may warrant regulatory action in addition to
restricted use classification, (2) **acute restricted use** \-- the
potential for acute risk to non-target organisms, but may be mitigated
through restricted use classification, (3) **acute endangered
species** - endangered species may be adversely affected by use, (4)
**chronic risk** - the potential for chronic risk may warrant regulatory
action, endangered species may potentially be affected through chronic
exposure, (5) **non-endangered plant risk** -- potential for effects in
non-target plants, and (6) **endangered plant risk** -- potential for
effects in endangered plants. Currently, OPP does not perform
assessments for chronic risk to plants, acute or chronic risks to
nontarget insects, or chronic risk from granular/bait formulations to
birds or mammals.

The ecotoxicity test values (measurement endpoints) used in the acute
and chronic risk quotients are derived from required studies. Examples
of ecotoxicity values derived from short-term laboratory studies that
assess acute effects are: (1) LC~50~ (fish and birds), (2) LD~50~ (birds
and mammals), (3) EC~50~ (aquatic plants and aquatic invertebrates) and
(4) EC~25~ (terrestrial plants). Examples of toxicity test effect levels
derived from the results of long-term laboratory studies that assess
chronic effects are: (1) LOAEC (birds, fish, and aquatic invertebrates),
and (2) NOAEC (birds, fish and aquatic invertebrates). For birds and
mammals, the NOAEC generally is used as the ecotoxicity test value in
assessing chronic effects, although other values may be used when
justified. However, the NOAEC is used if the measurement endpoint is
production of offspring or survival.

Risk presumptions and the corresponding RQs and LOCs are tabulated
below.

**Table 24. Risk Presumption Categories**

  ---------------------------------------------------------- ------------
  **Risk Presumption for Terrestrial Animals**               **LOC**

  Acute: Potential for acute risk for all non-target         \>0.5
  organisms                                                  

  Acute Restricted Use: Potential for acute risk for all     \>0.2
  non-target organisms, but may be mitigated through         
  restricted use classification                              

  Acute Endangered Species: endangered species may be        \>0.1
  adversely affected by use                                  

  Chronic Risk: potential for chronic risk may warrant       \>1
  regulatory action                                          

  **Risk Presumption for Aquatic Organisms**                 **LOC**

  Acute: Potential for acute risk for all non-target         \>0.5
  organisms                                                  

  Acute Restricted Use: Potential for acute risk for all     \>0.1
  non-target organisms, but may be mitigated through         
  restricted use classification                              

  Acute Endangered Species: endangered species may be        \>0.05
  adversely affected by use                                  

  Chronic Risk: potential for chronic risk may warrant       \>1
  regulatory action                                          

  **Risk Presumption for Terrestrial and Aquatic Plants**    **LOC**

  Potential for risk for all non-endangered and endangered   \>1
  plants                                                     
  ---------------------------------------------------------- ------------

> **Exposure and Risk to Nontarget Terrestrial Animals**

Exposure to avian and mammalian species from the application of
pesticides is usually estimated using the ELL-Fate Model (version 1.2)
(EPA, 1999) or other similar terrestrial model. The ELL-Fate model was
developed for agricultural pesticide uses, and calculates the decay of a
chemical applied to foliar surfaces for single and multiple
applications. The model takes into account the weight (lbs.) of active
ingredient applied per acre, the number of applications per year and the
half-life of the chemical in soil in order to estimate the chemical
concentration in the treated foliage.

Based on review of the model parameters, the ELL-Fate model was
determined to be inappropriate for the evaluation of risks to
terrestrial species from exposure to CCA, since this compound is applied
to processed lumber rather than agricultural crops. Birds, insects,
mammals, and plants may be exposed to CCA through direct contact with
treated lumber and contact with metals that have leached from treated
lumber into the surrounding soil. Uptake of these metals into plants and
insects, which are subsequently consumed by birds or mammals, can also
result in exposure. Exposure and toxicity data for direct contact with
treated lumber were not readily available; therefore, the terrestrial
assessment was based on exposure of ecological receptors to CCA
components in soil.

Risks to birds and mammals were evaluated using a simple terrestrial
food web model. To estimate exposure for receptor species, it was
assumed that metal leaching occurs from in-service CCA-treated wood into
the surrounding soil. The leached metals in soil were then assumed to be
taken up by terrestrial vegetation. Based on these conditions, the model
assumed that avian and mammalian receptor species would be exposed to
components of CCA through ingestion of vegetation and incidental
ingestion of soil.

The EECs used in this model were based on metal concentrations observed
in soils below seven CCA-treated decks ranging in age from 4 months to
15 years (Stilwell and Gorney, 1997). These data, summarized in the
table below, are assumed to be representative of metal concentrations in
soil that ecological receptors may be exposed to as the result of metal
leaching from existing CCA-treated structures. However, residential
decks constructed after January 2004 should have NO arsenic or chromium
residues. Public walkways, boardwalks, hand rails, docks, decks, or
other structures also cannot be built with CCA treated dimensional
lumber (2X4s, deck boards, etc.) which would serve to greatly reduce the
surface area from which leaching of arsenic or chromium into terrestrial
environments could occur.

**Table 25. Summary of Metal Concentrations (mg/kg) in Soil Under
CCA-Treated Decks\***

  -------------------------- --------------------- ----------------------
                             Maximum Concentration Mean Concentration

  Arsenic                    350                   76

  Chromium                   154                   43
  -------------------------- --------------------- ----------------------

> \*data from Stilwell and Gorny (1997).

The methods used to estimate the potential dose of CCA components to
avian and mammalian species through the ingestion of vegetation and soil
are provided in Appendix A. The results of the exposure assessment for
avian and mammalian species have been provided in Tables A1 and A2.
These tables also contain the estimated risk quotients (RQs) for avian
and mammalian species.

When more than one toxicity reference value was available for a
compound, toxicity data were selected for the risk assessment using the
following hierarchy of sources: 1) core studies from the pesticide
database, 2) supplemental studies from the pesticide database, 3) Health
Effects Division's Hazard Identification Assessment Review Committee
(HIRAC) reviews, 4) ECOTOX studies, and 5) studies from the open
literature. In cases where there was more than one toxicity value for
the same source, the lowest toxicity value was selected in order to be
conservative.

> **i. Birds**

As shown in Table A1, the risks to avian species from exposure to
arsenic and chromium in soil as a result of leaching from CCA-treated
structures do not appear to be significant.

**Table 26 Summary of RQs for Bobwhite quail from Table A2** (see
Appendix)

  ----------------------- ----------------------- -----------------------
                          ACUTE RQs               CHRONIC RQs

                          Average - Maximum       Average - Maximum

  Arsenic acid            0.03 **0.16**           0.19 0.89

                                                  

  Chromic acid            0.00 0.02               0.43 **1.54**
  ----------------------- ----------------------- -----------------------

The acute and chronic RQs that were based on mean soil concentrations
did not exceed any of the respective levels of concern. The only
exceedence for acute exposure was the RQ for a maximum residue level of
arsenic (0.16) which was greater than the acute endangered species level
of concern of 0.1. The chronic RQs based on maximum soil concentrations
slightly exceeded the chronic risk concern level (\>1.0) for chromium
with a RQ of 1.54.

**ii. Mammals**

**Table 27 Summary of RQs for Meadow Vole from Table A4** (see Appendix)

  ----------------------- ----------------------- -----------------------
                          ACUTE RQs               CHRONIC RQs

                          Average - Maximum       Average - Maximum

  Arsenic acid            0.04 **0.20**           **1.24 5.72**

                                                  

  Chromic acid            0.02 0.07               **4.37 15.66**
  ----------------------- ----------------------- -----------------------

As shown in Table A4, the RQs based on mean soil concentrations **did
not exceed any acute levels of concern** (LOCs) for arsenic acid or
chromic acid. Acute maximum soil residues slightly exceed the endangered
species LOC (\>1.0) for arsenic acid.

Chronic RQs based on mean soil concentrations slightly exceeded the
chronic risk LOC of \>1.0 for arsenic (RQ of 1.24) and chromic acid (RQ
of 4.37). The chronic RQs based on maximum soil concentrations also
exceed the chronic risk LOC for both arsenic and chromium. The actual
risk levels for mammalian species may be lower than the estimated RQs
due to the conservative assumptions used in the model.

> **Conclusions of the Risk Assessment for Birds and Mammals:**

Based on conservative model assumptions, the results indicate that the
potential for adverse effects to birds and mammals from exposure to
average concentrations of CCA components in soil is low. Average soil
concentrations are considered more likely to represent the exposure
level for mobile receptor species such as birds and mammals than maximum
soil concentrations under existing CCA treated decks. Decks built after
the CCA ban on dimensional lumber will not leach arsenic or chromium. A
quantitative assessment of the risks to birds and mammals from direct
contact with CCA-treated lumber was not conducted, however, they are
expected to be minimal.

**iii. Insects**

Exposure to CCA components from treated lumber and the surrounding soil
may result in adverse effects to insects such as honey bees. The
potential risks to insects could not be quantitatively evaluated,
however, since exposure data for insects were not readily available. Bee
hives constructed from treated wood have been shown to cause toxicity to
bees and result in residues of wood preservatives in honey (Kalnins and
Detroy, 1984). The CCA product labels contain a label statement that
restricts use of CCA treated wood for construction or maintenance of bee
hives.

> **Exposure and Risk to Nontarget Freshwater and Marine/Estuarine
> Aquatic Organisms**

Freshwater and marine/estuarine aquatic organisms could potentially be
exposed to the components of CCA via residues leached from treated wood
into the aquatic environment, either as runoff from land-based
structures, such as utility poles, or from CCA-treated structures which
stand directly in aquatic habitats, such as docks, piers, pilings, and
bulkheads.

A risk assessment for copper as a component of inorganic arsenical wood
preservatives is not included in this RED, as explained in the Executive
Summary, above. However, copper is known to be highly toxic to aquatic
organisms. While CCA-treated wood does leach copper into aquatic
environments (Hobson, 2000), other copper-containing wood preservatives
have been shown to leach greater amounts of copper (Townsend et al.,
2001), and the copper-containing wood preservatives that do not contain
arsenic are likely to be more toxic to marine organisms than CCA (Weis
and Weis, 1996). Additionally, copper is found in aquatic habitats from
a variety of other pesticidal uses, such as marine antifoulants and
agricultural applications. The forthcoming copper RED will address all
of the pesticidal uses of copper, and will provide a complete assessment
of the risks they pose to aquatic organisms.

There are two major ways in which the components of CCA can reach
aquatic habitats:

1\. The metals can leach directly from CCA-treated structures installed
in or above the water, such as bracing timbers, pilings and bulkheads.
There are numerous published studies which provide data on the leaching
of CCA components from these types of structures \[Brooks, 1997; Hobden,
2000; Townsend et al, 2001\]; however the data are extremely variable
because leaching rates of the metals depend on many factors, such as the
salinity and pH of the water or leaching solution, age of the wood, type
of wood, and retention time. Additionally, much of the data are reported
as losses of metals from the wood as opposed to metal concentrations of
the leachate. There is also a lack of validated methods for estimating
the dispersion of the metals into the larger aquatic environment
surrounding the treated structures, so developing a realistic estimation
of risk from these structures is difficult.

Lee et al (1993) examined freshwater leaching of CCA components in a
laboratory test, involving exposing 2.5 cm2 yellow pine cubes to a water
bath for 14 days and measuring the leachate concentrations of the
metals. The range of values for chromium and arsenic from these studies
are summarized in the table below. Townsend et al (2001) performed
leaching tests with CCA-treated wood using a variety of methods:
deionized water, salt water, Synthetic Precipitation Leaching Procedure
(SPLP),and Toxicity Characteristic Leaching Procedure (TCLP). The range
of values from these tests is also reported in the table below.

**Table 28. Maximum and Minimum Leaching Values from Lee et al, 1993 (as
cited in Hobden, 2000 and Brooks, 1997) and Townsend et al, 2001.**

  ------- --------------- ------------ ----------------- ------------------
          Lee et al., min Lee et al.,  Townsend et al,   Townsend et al,
          (mg/L)          max (mg/L)   min (mg/L)        max (mg/L)

  As      19              28           3.6               8.9

  Cr      3               28           1.8               3.4
  ------- --------------- ------------ ----------------- ------------------

2\. The metals can leach from CCA-treated structures into soil, and
reach aquatic habitats via surface runoff.. Since the model typically
used by OPP to determine EECs from surface runoff \[e.g., the Generic
Expected Environmental Concentrations (GENEEC) model (USEPA, 2001)\] was
developed for organic compounds, it is not appropriate to use it to
model the runoff of metals leached from CCA-treated structures. Cooper
(1990, as cited in Brooks, 1997) examined the concentration of metals in
run-off water from CCA-treated poles and lumber exposed to natural rain;
these values are provided in the table below.

**Table 29. Maximum and Minimum Runoff Values from Cooper, 1990 (as
cited in Brooks, 1997).**

  ------------- ------------------------- --------------------------------
                poles (mg/L)              lumber (mg/L)

  As            0.300                     1.1 - 7.3

  Cr            0.400                     0.080 - 1.0
  ------------- ------------------------- --------------------------------

Attempting to estimate realistic EECs for arsenic and chromium leaching
from CCA-treated wood is extremely difficult. Water-column
concentrations of these metals in aquatic habitats would likely be much
lower than the values obtained in the leaching studies discussed above,
due to dispersion in the water body and partitioning into biota and
sediment; however, there are no methods currently available to OPP to
reliably quantify these effects and estimate realistic water-column
EECs. Calculating risk quotients (RQ ) using the published values as
"worst-case" EECs is not useful, given the variability of the values and
the high degree of uncertainty in

extrapolation of results to "real-world" conditions. Therefore, a
numerical risk assessment for aquatic organisms will not be performed at
this time.

Background levels of arsenic and chromium in a wetland study in the
Pacific NW U.S. found the following levels (Lebow, et al, 2000):

Chromium in soil: 6 to 8 ppm

Chromium in sediment: 7 to 14 ppm

Chromium in wetland water: 2 ppb

Arsenic in soil: 1 to 3 ppm

Arsenic in sediment: 1 to 4 ppm

Arsenic in wetland water: 1 ppm

Background levels of \>10 ppb arsenic in surface waters in the U.S.
occur more often in some Midwestern areas, however, most areas of the
U.S. experience levels lower than 10 ppb. EPA estimates of background
levels of chromium in U.S. freshwaters range from 0.1 to 35 ppb, and 0.3
ppb in seawater (EPA web sources).

Generally, the impact of CCA treated wood in an aquatic environment
depends on surface area exposed to leaching; the leaching rate itself;
metal speciation that varies under different environmental conditions;
rate of uptake, depuration, and bioaccumulation by epibiota; tidal
activity and flushing of water around CCA structures; adsorption of
metals by sediment; and trophic transfer from sediments to aquatic
organisms.

Published literature on effects to aquatic organisms from the use of
CCA-treated wood in direct contact with water has shown that the metals
leached from it (primarily copper) are taken up by biota and can have
adverse effects (Weis and Weis, 1995). The most affected aquatic
community appears to be the epibiotic, or "fouling," community, which
grows in direct contact with treated structures (Weis and Weis, 1996),
but effects on benthic community diversity were also observed, and were
correlated with elevated levels of metals, primarily copper, in
sediments adjacent to treated wood (Weis and Weis, 1996). Copper leaches
the most of the three metals (Weis and Weis, 2002), and it is known to
be the most toxic of the three metals to aquatic organisms. The leaching
of metals and the corresponding toxic effects are greatest when the wood
is new in poorly flushed areas having low water circulation (Weis et al,
1991, 2002).

**C. Uncertainties in the Risk Assessment**

This report relied heavily on available laboratory conducted literature.
Additional study of CCA metals speciation and bioavailability under
different in-field environmental conditions may be warranted. For
example, the toxicity of metals to terrestrial receptors will depend on
many site-specific factors such as the soil type (e.g., sand, loam,
clay, etc.), soil pH, organic content of the soil, and soil moisture
which will affect the availability of the metals to the receptors.

Toxicity data were not available for terrestrial plants, as a result the
risks to terrestrial plants could not be evaluated. Aquatic plant
toxicity data for chromic acid are limited. The impact on aquatic
animals of consuming elevated levels of arsenic or chromium in plants
was not assessed.

Chromium III toxicity data were used to evaluate risks to avian
receptors since chromium VI toxicity data were not available. Because
chromium VI and chromium III often have different levels of toxicity,
the risk levels estimated based on chromium III toxicity data are
uncertain relative to exposure to chromium VI. Movement from Chromium
III to VI and back again under various aquatic environmental conditions
is not well understood.

Synergistic and antagonistic effects of the combined components of CCA
(arsenic, chromium, and copper) to terrestrial and aquatic organisms are
not known. These studies would be difficult to conduct, however, field
studies are an option.

The behavior of metals in the terrestrial or aquatic environments is
difficult to predict, resulting in large uncertainty when estimating
environmental concentrations. Terrestial EECs only estimate soil
exposure. Models that estimate bioavailability of metals in water are
unavailable, requiring reliance on open literature.

**IV - Endangered Species**

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

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

For certain use categories, the Agency assumes there will be minimal
environmental exposure, and only a minimal toxicity data set is required
(Overview of the Ecological Risk Assessment Process in the Office of
Pesticide Programs U.S. Environmental Protection Agency - Endangered and
Threatened Species Effects Determinations, 1/23/04, Appendix A, Section
IIB, pg.81). Chemicals in these categories therefore do not undergo a
full screening-level risk assessment. However, wood treatment uses of
CCA have high potential for environmental exposure.

The results of the terrestrial risk assessment indicate that threatened
and endangered birds may be adversely affected by arsenic residues
leached from existing CCA-treated deck structures. Birds may also be
adversely affected on a chronic basis by chromium leached from those
structures. These estimates are based on maximum exposure estimates,
however. Average estimated levels of arsenic and chromium are not likely
to impact sensitive avian species. Maximum exposure estimates indicate
that arsenic may cause adverse acute effects to endangered and
threatened mammal species, and both arsenic and chromium may adversely
affect mammals from chronic exposure. Average predicted exposure levels
for both metals are still high enough to cause concern for chronic
adverse effects to mammals. Decks, boardwalks, and other structures
built after January 2004 are not expected to pose a significant risk of
arsenic or chromium exposure to non-target or listed birds or mammals.

Since it is not possible to quantify the risk to aquatic organisms from
arsenic and chromium leached from treated wood, it is not known whether
Endangered Species Levels of Concern are exceeded. Literature indicate
that metals leaching out of CCA wood, primarily copper, may adverse
affect aquatic epibiotic and benthic organism richness and diversity in
areas close to or on treated wood surfaces. Other effects noted in
literature include limited pathological and genotoxic effects, plus
inhibition of beneficial bacterial that degrade pentachlorophenol (Weis
and Weis, 2002). Based on these observed effects, and considering the
known toxicity of the component metals, particularly copper, to aquatic
organisms, it is possible that the component metals of CCA could
adversely impact endangered or threatened aquatic organisms,
particularly those in epibiotic or benthic communities which cannot move
away from treated wood leachate.

If it is determined that there is potential for CCA wood treatment uses
to overlap with listed species and that a more refined assessment is
warranted, to include direct, indirect and habitat effects, the refined
assessment should involve clear delineation of the action area
associated with CCA wood treatment uses and best available information
on the temporal and spatial co-location of listed species with respect
to the action area. This analysis has not been conducted for this
assessment. An endangered species effect determination will not be made
at this time.

**V -- Confirmatory Data Needs**

**850.2300 -- Avian reproduction study using chromic acid**

**850.1735 -- Freshwater invertebrate sediment toxicity using arsenic
acid**

**850.1735 - Freshwater invertebrate sediment toxicity using chromic
acid**

**850.1740 - Marine invertebrate sediment toxicity using arsenic acid**

**850.1740 - Marine invertebrate sediment toxicity using chromic acid**

**850.4400 -- *Lemna gibba* aquatic plant toxicity using chromic acid**

**850.5400 - *Skeletonema costatum* aquatic plant toxicity using arsenic
acid**

**850.5400 - *Selenastrum capricornutum* aquatic plant toxicity using
chromic acid**

**850.5400 -- *Anabaena flos-aquae* aquatic plant toxicity using chromic
acid**

**850.5400 -- *Skeletonema costatum* aquatic plant toxicity using
chromic acid**

**850.5400 -- *Navicula pelliculosa* aquatic plant toxicity using
chromic acid**

**850.4225 -- Seedling Emergence terrestrial plant toxicity using
arsenic acid**

**850.4225 - Seedling Emergence terrestrial plant toxicity using chromic
acid**

**850.4250 -- Vegetative Vigor terrestrial plant toxicity using arsenic
acid**

**850.4250 -- Vegetative Vigor terrestrial plant toxicity using chromic
acid**

**VI - Label Statements**

**Product labels must state: "This product is toxic to birds, mammals,
fish, and aquatic invertebrates."**

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*APPENDIX A*

***CCA: Arsenic, Chromium and Copper Exposure Assessment for Avian and
Mammalian Species***

*The meadow vole (Microtus pennsylvanicus) was selected as the mammalian
receptor species for evaluating potential effects of the components of
CCA to mammals. The meadow vole is primarily herbivorous and is widely
distributed in the United States (EPA, 1993). The northern bobwhite
(Colinus virginianus) was selected as the avian receptor species for
evaluating potential effects of the components of CCA to avian species.
The northern bobwhite feeds mainly on seeds and low-lying vegetation.
The bobwhite range includes the eastern and central U.S. as well as
portions of the Rocky Mountains and the southwest. The mouse and
bobwhite were selected because a relatively large proportion of the diet
of both species is comprised of vegetation and there is an extensive
amount of toxicity data available for these species, particularly for
the bobwhite.*

*The following discussion presents the methods used to calculate the
potential ingestion of chemicals by the mouse and bobwhite via the
ingestion of food (i.e., terrestrial plants) and surface soil. The
equations presented below were derived based on equations presented by
EPA (1989). The following equation was used to calculate the dose of
chemicals that a mouse or bobwhite would be expected to obtain from the
ingestion of terrestrial plants:*

*(1)*

*where:*

> *Dose~plant~ = amount of chemical ingested per day via ingestion of
> plants (mg/kg bw-d);*

*FI = food ingestion rate (kg/kg bw-d); and*

*C~diet~ = estimated chemical concentration in diet (mg/kg).*

*Food ingestion rates (FI) of 0.35 kg/kg bw-d for adult voles (EPA,
1993) and 0.093 kg/kg bw-d for adult bobwhites (EPA, 1993) were used in
the assessment.*

*The estimated dietary concentration (C~diet~) was calculated using the
following equation:*

*(2)*

*where:*

*P~p~ = proportion of diet consisting of vegetation (unitless); and*

*C~p~ = estimated concentration of COPC in vegetation (mg/kg).*

*The proportion of the diet (P~p~) consisting of vegetation for both the
vole and bobwhite was assumed to be 100%. This value is fairly
consistent with the data compiled in EPA (1993) for these species. For
both voles and bobwhites it was also assumed that 100% of the plants
ingested are from the areas with elevated concentrations of CCA. This
assumption is conservative and may lead to an overestimate of potential
risks because the species are likely to also forage in areas that may
not have elevated soil concentrations.*

*The concentration of a chemical in a terrestrial plant (C~p~) as fresh
weight was determined using the following equation:*

$C_{p} = C_{\text{soil}}\text{*BCF}$ *(3)*

*where:*

*C~soil~ = concentration of COPC detected in surface soil (mg/kg); and*

*BCF = bioconcentration factor for the chemical in terrestrial plants
(unitless).*

*The maximum concentration of the chemical was used as the C~soil~ in
the model for voles and bobwhites in order to be conservative. However,
the model for voles and bobwhites was also run using average
concentrations as the C~soil~ to estimate plant concentrations since
average soil concentrations may be more representative of the potential
for exposure of mobile avian and mammalian species.*

*Bioconcentration Factors (BCFs) compiled by Baes et al. (1984) were
used to calculate the chemical concentrations in plants for the
assessment. The BCFs for arsenic, chromium and copper were 0.04, 0.0075
and 0.4, respectively. Employing equations 1, 2, and 3, the estimated
dose that bobwhites and voles would receive from ingestion of plants in
the vicinity of a CCA-treated structure (e.g., deck) is provided in
Tables A1 and A2, respectively.*

***In addition to the ingestion of chemicals accumulated in vegetation,
bobwhites and voles also may be exposed to chemicals through the
inadvertent ingestion of surface soil while foraging or grooming. The
following equation was used to calculate the dose of chemical that voles
and bobwhites would be expected to obtain from the ingestion of surface
soil:***

$\text{Dose}_{\text{soil}}\text{ = SI * }C_{\text{soil}}$*(4)*

*where:*

*Dose~soil~ = amount of chemical ingested per day from soil (mg/kg
bw-d);*

> *SI = soil ingestion rate (kg/kg bw-d); and*
>
> *C~soil~ = chemical concentration in surface soil (mg/kg).*

*Based on percent dietary soil ingestion values presented by Beyer et
al. (1994), it was assumed that 10% of the total mass of both the vole
and the bobwhites' diet consists of soil. The percent soil ingestion was
multiplied by the food ingestion rates (FI) presented earlier for these
species to estimate soil ingestion rates (0.035 kg/kg bw-d for voles and
0.0093 kg/kg bw-d for bobwhites). In order to be conservative, the
maximum chemical concentration was used for C~soil~ to estimate the dose
received from soil ingestion. However, average soil concentrations were
also used to estimate the dose received from soil ingestion for voles
and bobwhites which may be more representative of the potential for
exposure for these mobile species. Employing equation 4, the estimated
dose voles and bobwhites would receive from the ingestion of soil for
arsenic, chromium and copper are discussed in the report.*

*The total dietary exposure levels for voles and bobwhites was
determined using the following equation:*

$\text{Dose}_{\text{total}} = \text{Dose}_{\text{plant}} + \text{Dose}_{\text{soil}}$
*(5)*

***Using equation 5, the estimated total dose voles and bobwhites would
be expected to receive from the ingestion of plants and soil in the
vicinity of a CCA-treated structure is shown in Tables A1 and A2,
respectively.***

***In the Risk Characterization section, the total dietary intakes are
compared to toxicity reference values (e.g., LD50, NOAEL) to determine
if adverse effects are likely to occur in voles and bobwhites from the
ingestion of CCA components in terrestrial plants and surface soil. Many
of the toxicity reference values for avian species were based on
laboratory toxicity data on the bobwhite so no scaling factor was needed
to adjust for body weight. In certain cases, however, the toxicity
reference values were based on toxicity data from other avian species
such as the mallard duck or black duck. These toxicity reference values
were not adjusted for the bobwhite's body weight based on
recommendations in Sample et al. (1996). Toxicity reference values for
mammals were adjusted to the vole's body weight using the following
equation provided in Sample et al. (1996):***

$\text{NOAEL}_{w} = \text{NOAEL}_{t}\text{* }(\text{bw}_{t}\text{/bww})^{\text{1/4}}$
*(6)*

*Where:*

*NOAEL~w~ = NOAEL for mammalian wildlife species (e.g., meadow vole)*

*NOAEL~t~ = NOAEL for laboratory mammalian species (e.g., rat, rabbit,
etc.)*

*bw~w~ = body weight for mammalian wildlife species (e.g., meadow vole)*

*bw~t~ = body weight for laboratory mammalian species (e.g., rat,
rabbit, etc.)*

*The body weight for the meadow vole was assumed to be 0.044kg and body
weights for the rat, rabbit, mouse and mink were assumed to be 0.35kg,
3.8kg, 0.035kg, and 1.0kg, respectively, based on reference values
provided in Sample et al. (1996) and EPA's Wildlife Exposure Factors
Handbook (EPA, 1993).*

*Following adjustment of the mammalian toxicity reference values, the
total dose for the bobwhite and vole of arsenic, chromium and copper
were compared with the toxicity reference values for these contaminants
to determine the risk quotients (RQs). The RQs for the bobwhite and vole
based on exposure to CCA components in the vicinity of a CCA-treated
structure are shown in Table A1 and Table A2.*

*Blank for Table A1*

*Blank for table A2*