Document ID: EPA-HQ-OPP-2007-0589-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-07-25T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES

 

MEMORANDUM								July 17, 2007

SUBJECT:		Ecological Hazard and Environmental Risk Assessment Chapter
for Naphthenate Salts Reregistration Eligibility Decision (RED) Document
(Case No.: 3099)		

FROM:		Genevieve Angle, Biologist

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

TO:			Mark Hartman, Branch Chief

Diane Isbell, Team Leader

Kathryn Avivah Jakob, Chemical Review Manager

Timothy McMahon, Risk Assessor

Regulatory Management Branch II

Antimicrobials Division (7510P)

THRU:		Nader Elkassabany, Team Leader, Team Two

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

Norman Cook, Branch Chief

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510P)

Chemical Names				PC Codes		

Copper Naphtheante/ Zinc Naphthenate	023102, 088301

Attached is the Ecological Hazard and Environmental Risk Assessment
chapter for the naphthenate salts RED Document.



ECOLOGICAL HAZARD AND ENVIRONMENTAL 

RISK ASSESSMENT CHAPTER

Naphthenate Salts

PC Codes 023102, 088301

CASE No.: 3099

05/14/07

Genevieve Angle, Biologist

Antimicrobials Division

Office of Pesticide Programs

U.S. Environmental Protection Agency

1200 Pennsylvania Avenue, NW

Washington, DC 20460

Table of Contents

												    Page

Executive Summary
………………………………………………………………
……………… 1

1.  Ecological Toxicity Data . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3  

A.  Toxicity to Terrestrial Animals . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . .3 

1.  Birds, Acute  . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . 3

2.  Birds, Subacute. . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . 4 

3.  Mammals, Acute and Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .5  

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

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

2.  Freshwater Invertebrates, Acute . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .6  

3.  Estuarine and Marine Organisms, Acute . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . .7 

4.  Aquatic Organisms, Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .7

C.  Toxicity to Plants . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . ..7

II.  Risk Assessment and Risk Characterization . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . ..8

A.  Environmental Fate Assessment Summary . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . .. . . . ..8

B.  Environmental Exposure And Ecological Risk Assessment. . . . . . . .
. . . . . . . . .. . ... . . . .9 

C.  Endangered Species Considerations . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . .  . . . . . . . . . ..13

III.  Confirmatory Data Required . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . ... 14   

IV.  Label Hazard Statements for Terrestrial and Aquatic Organisms . . .
. . . . . . ..  . . . . . . . . . .15

V.  References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . 16

LIST OF TABLES

																			  Page

Table 1 – Acute Oral Toxicity of Naphthenate Salts to Birds. . . . . .
. . . . . . . . . . . . . . . . . . . . .3 

				

Table 2 – Subacute Oral Toxicity of Naphthenate Salts to Birds. . . .
. . . . . . . . . . . . . . . . . . . . 4

Table 3 – Acute Toxicity of Naphthenate Salts to Freshwater Fish. . .
. . . . . . . . . . . . . . . . . . . 5

Table 4 – Acute Toxicity of Naphthenate Salts to Freshwater
Invertebrates. . . . . . . . . . . . . . . 5 



	Ecological Hazard and Environment Risk Assessment

For Naphthenate Salts

Executive Summary:

		Naphthenate salts (copper naphthenate and zinc naphthenate) are
currently registered as fungicides, insecticides and miticides for
materials preservation and wood preservation.  Materials preservative
uses include:  fabrics and textiles, rope, burlap, canvas, cellulosic
materials, boat coverings and sails, nets, seines, tents, awnings,
particle board and insulation board.  Wood preservative uses include:
lumber, timber, logs, plywood, posts, poles, fences, pilings, flooring,
shingles, siding, sills, steps, doors, flower boxes, decks/porches,
roofs, ladders, outdoor furniture, landscaping material, millwork,
docks, piers, boat hulls and boats. 

	The wood treatment uses of naphthenate salts have high potential for
environmental exposure and thus require an environmental risk
assessment.  Use of treated nets and seines also may provide for
environmental exposures, but copper naphthenate wood treatment uses are
expected to provide for greater environmental exposure and are assessed
here.  All other uses are considered indoor and have minimal to no
environmental exposure potential following use.  

EPA has performed an environmental risk assessment using estimated
environmental concentrations (EECs) for naphthenate salts developed by
modeling copper naphthenate’s release from a dock into water and
toxicity values from the tables in section I to develop risk quotients
(RQs) and compare them to levels of concern (LOCs).  LOCs were exceeded
for freshwater fish and freshwater invertebrates in bodies of water 6
acre feet in size; however, as discussed below an endangered species
effects determination will not be made at this time.  There were no
acute toxicity studies available for estuarine and marine organisms nor
were there any acceptable chronic toxicity studies available for aquatic
organisms.  There were also no studies available for aquatic plants. 
Therefore, risk to these species could not be assessed.  Modeling was
not conducted for zinc naphthenate, but environmental exposures are
assumed to be similar to those for copper naphthenate.

 

Data Gaps:  

	Confirmatory Data Required For Wood Treatment Risk Assessment:

Acute aquatic invertebrate study (850.1010) (zinc naphthenate),

Estuarine/marine fish acute study (850.1075) (both copper and zinc
naphthenate),

Estuarine/marine shrimp acute study (850.1035) (both copper and zinc
naphthenate),

Estuarine/marine mollusk acute study (850.1025) (both copper and zinc
naphthenate),   

Acute sediment toxicity to freshwater invertebrates (850.1735) (both
copper and zinc naphthenate),

Acute sediment toxicity to estuarine invertebrates (850.1740) (both
copper and zinc naphthenate),

Fish bioconcentration study – BCF (850.1730) (both copper and zinc
naphthenate),

Aquatic invertebrate (freshwater) life-cycle study (850.1300) (both
copper and zinc naphthenate),

Fish early life-stage (freshwater) study (850.1400) (both copper and
zinc naphthenate),1

Fish early life-stage (estuarine/marine) study (850.1400) (both copper
and zinc naphthenate),1

Chronic mysid shrimp study (850.1350) (both copper and zinc
naphthenate),1

Freshwater green alga (850.5400) (both copper and zinc naphthenate),

Freshwater diatom (850.5400) (both copper and zinc naphthenate),

Blue-green cyanobacteria (850.5400) (both copper and zinc naphthenate),

Marine diatom (850.5400) (both copper and zinc naphthenate),

Freshwater floating macrophyte duckweed (850.4400) (both copper and zinc
naphthenate),

Freshwater rooted macrophyte rice seedling emergence (850.4225) (both
copper and zinc naphthenate),

Freshwater rooted macrophyte rice vegetative vigor (850.4250) (both
copper and zinc naphthenate),

Wood leaching study (AWPA E11-06) (both copper and zinc naphthenate),

Environmental runoff monitoring study (None) (both copper and zinc
naphthenate).  This test can be waived provided labels are amended as
outlined below for wood preservative labels,

Residues in honey/beeswax and toxicity of treated wood residues to bees
– combination of Guideline 860.1500 and 850.3030 (“Honey Bee
Toxicity of Residues on Foliage.”).  The toxicity portion of this
study is in lieu of the honeybee contact LD50 test 850.3020.  The
residue and toxicity test can be waived provided the label is amended to
prohibit the use of treated wood for beehive construction, with a
statement such as, “Wood treated with copper/zinc naphthenate shall
not be used in the construction of beehives.” (both copper and zinc
naphthenate).

Label Hazard Statements/Use Recommendations:

Naphthenate salts labels must state:  

“This pesticide is toxic to aquatic invertebrates, shrimp, and
oysters/clams.”

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

Wood preservative labels must state:  "Treated lumber must be stored
under cover, indoors, or at least 100 feet from any pond, lake, stream,
wetland, or river to prevent possible runoff of the product into the
waterway.  Treated lumber stored within 100 feet of a pond, lake,
stream, wetland, or river must be either covered with plastic or
surrounded by a berm to prevent surface water runoff into the nearby
waterway.  If a berm or curb is used around the site, it should consist
of impermeable material (clay, asphalt, concrete) and be of sufficient
height to prevent runoff during heavy rainfall events.”

The honeybee residue and toxicity test can be waived provided the label
is amended to prohibit the use of treated wood for beehive construction,
with a statement such as, “Wood treated with copper/zinc naphthenate
shall not be used in the construction of beehives.

I.	Ecological Toxicity Data

	The toxicity endpoints presented below are based on the results of
ecotoxicity studies submitted to EPA to meet the Agency’s data
requirements for the uses of naphthenate salts.

	A.	Toxicity to Terrestrial Animals

(1)	Birds, Acute 

	In order to establish the toxicity of naphthenate salts to avian
species, the Agency requires an acute oral toxicity study using the
technical grade active ingredient (TGAI).  The preferred test species is
either mallard duck (a waterfowl) or bobwhite quail (an upland game
bird).  The results of two acute oral toxicity studies, submitted for
naphthenate salts, are provided in the following table (Table 1).

	

Table 1.  Acute Oral Toxicity of Naphthenate Salts to Birds

Species	

Chemical,

% Active Ingredient

(a.i.)

Tested	

Endpoint

(mg/kg)	

Toxicity Category	

Satisfies Guidelines/

Comments	

Reference

(MRID No.)

Bobwhite quail

(Colinus virginianus)	Copper Naphthenate 9.55%	LD50 = >2250

NOAEL = <292

	Relatively nontoxic	Yes (core)

- 14-day test duration

- 19 weeks of age	423486-01

Bobwhite quail

(Colinus virginianus)	Zinc Naphthenate

14.33%	LD50 = >2250

NOAEL = <175

	Relatively nontoxic	No (supplemental)

- 14-day test duration

- 19 weeks of age

- data not provided to support the NOEL	423486-04

	These acceptable acute oral toxicity studies on the bobwhite quail
indicate that naphthenate salts are relatively nontoxic on an acute oral
basis. The guideline requirement OPPTS 850.2100/(71-1) is satisfied.  

(2)	Birds, Subacute

	A subacute dietary study using the TGAI may be required on a
case-by-case basis depending on the results of lower-tier ecological
studies and pertinent environmental fate characteristics in order to
establish the toxicity of a chemical to avian species.  This testing was
required for naphthenate salts.  The preferred-test species is either
the mallard duck or bobwhite quail.  The results of four subacute
dietary toxicity studies, submitted for naphthenate salts, are provided
in the following table (Table 2).

Table 2.  Subacute Oral Toxicity of Naphthenate Salts to Birds

Species	

Chemical,

% Active Ingredient

(a.i.)

Tested	

Endpoint

(ppm)	

Toxicity Category	

Satisfies Guidelines/

Comments	

Reference

(MRID No.)

Bobwhite quail

(Colinus virginianus)	Zinc Naphthenate 

14.33%	LC50 (diet) = >5620

NOAEC = 5620	Relatively nontoxic	Yes (core for TEP)

-	8-day test duration

-	10 days of age	423486-05

Mallard duck

(Anas platyrhynchos)	Zinc Naphthenate

14.33%	LC50 (diet) = >5620

NOAEC = 5620	Relatively nontoxic	Yes (core for TEP)

-	8-day test duration

-  10 days of age	423486-06

Bobwhite quail

(Colinus virginianus)	Copper Naphthenate

9.55%	LC50 (diet) = >5620

NOAEC = 1780	Relatively nontoxic	Yes (core)

-  8-day test duration

-  10 days of age	423486-02

Mallard duck

(Anas platyrhynchos)	Copper Naphthenate 

9.55%	LC50 (diet) = >5620

NOAEC = 5620	Relatively nontoxic	Yes (core)

-  8-day test duration

-  10 days of age	423486-03

	The results from four acceptable studies indicate that naphthenate
salts are relatively nontoxic to avian species through subacute dietary
exposure. These studies fulfill guideline requirements OPPTS 850.2100/
(71-2a – Bobwhite quail and 71-2b – Mallard duck). 

 (3)	Mammals, Acute and Chronic Toxicity

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

B.	Toxicity to Aquatic Animals

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

(1)	Freshwater Fish, Acute

	In order to establish the acute toxicity of naphthenate salts to
freshwater fish, the Agency requires freshwater fish toxicity studies
using the TGAI.  The preferred test species are rainbow trout (a
coldwater fish) and bluegill sunfish (a warmwater fish).  The results of
two freshwater fish acute studies submitted for naphthenate salts, 1
coldwater and 1 warmwater, are presented in Table 3.

 Table 3.  Acute Toxicity of Naphthenate Salts to Freshwater Fish 

Species	

Chemical,

% Active Ingredient

(a.i.)

Tested	

Endpoint

(mg/L)	

Toxicity Category	

Satisfies Guidelines/

Comments	

Reference

(MRID No.)

Bluegill Sunfish (Lepomis macrochirus)	Copper naphthenate

98.9%	LC50 = 3.1

	Moderately toxic	Yes (core)

-	96-hr test duration

-	static renewal test system	424891-01

Rainbow Trout (Oncorhynchus mykiss)	Zinc naphthenate

98.9%	LC50 = 1.1

NOAEC = 0.39	Moderately toxic	Yes (core)

-	96-hr test duration

-	static test system	424891-02

	Freshwater acute toxicity tests indicate that naphthenate salts are
moderately toxic to fish on an acute basis.  Study 424891-02 fulfills
the guideline requirement for the coldwater species and study 424891-01
fulfills the guideline requirement for the warmwater fish species under
OPPTS 850.1075 (72-1a&b).  

	(2)	Freshwater Invertebrates, Acute

	The Agency requires a freshwater aquatic invertebrate study using the
TGAI to establish the acute toxicity to freshwater invertebrates.  The
preferred test species is Daphnia magna.  The results of one study
submitted for naphthenate salts are provided in the following table
(Table 4).

	Table 4.  Acute Toxicity of Naphthenate Salts to Freshwater
Invertebrates

 

Species	

Chemical,

% Active Ingredient

(a.i.)

Tested	

Endpoint

(mg/L)	

Toxicity Category	

Satisfies Guidelines/

Comments	

Reference

(MRID No.)

Waterflea (Daphnia magna)	Copper Naphthenate

95.6%	EC50 = 0.34 

NOAEC = 0.12 	Highly toxic	Yes (core)

-	48-hr test duration

-	static test system 	424891-03

	The results of 424891-03 indicate that naphthenate salts are highly
toxic to freshwater invertebrates.  This study fulfills guideline
requirement OPPTS 850.1010 (72.2a).  Because the acute aquatic
invertebrate toxicity value is < 1.0 mg/L, the environmental hazard
section of naphthenate salts labels must state:  “This pesticide is
toxic to aquatic invertebrates.”

(3)	Estuarine and Marine Organisms, Acute

	Acute toxicity testing with estuarine and marine organisms using the
TGAI is required when the end-use product is intended for direct
application to the marine/estuarine environment or effluent containing
the active ingredient is expected to reach this environment.  The
preferred fish test species is the sheepshead minnow.  The preferred
invertebrate test species are mysid shrimp and eastern oysters.  This
testing is required for naphthenate salts based on the chemical’s
potential to reach estuarine and marine environments.  No studies have
been submitted to fulfill these data requirements (OPPTS
850.1075/(72-3a), OPPTS 850.1035/(72-3c) and OPPTS 850.1025/(72-3b)).

 (4)	Aquatic Organisms, Chronic

	Chronic toxicity testing (fish early life stage and aquatic
invertebrate life cycle) is required for pesticides when certain
conditions of use and environmental fate apply.  Preferred freshwater
and estuarine/marine fish and invertebrate species include:  fathead
minnow, rainbow trout, Daphnia magna, and mysid shrimp.  This testing is
required for naphthenate salts.  No studies have been submitted to
fulfill these data requirements (OPPTS 850.1300, 850.1350, and
850.1400).	 

Toxicity to Plants

	Non-target plant phytotoxicity testing is required for pesticides when
certain conditions of use and environmental fate apply.  Naphthenate
salts uses as a wood treatment may result in chemical leachate from
treated wood into the aquatic environment.  Aquatic plant toxicity data
are necessary for a non-target plant risk assessment.  Testing is
conducted with one species of aquatic vascular plant (Lemna gibba) and
four species of algae:  (1) freshwater green alga, Selenastrum
capricornutum, (2) marine diatom, Skeletonema costatum, (3) freshwater
diatom, Navicula pelliculosa, and (4)  bluegreen cyanobacteria, Anabaena
flos-aquae.  The rooted aquatic macrophyte rice (Oryza sativa) is also
tested in seedling emergence and vegetative vigor tests. 

	Four algal toxicity tests under 850.5400 are outstanding:  freshwater
green alga (Selenastrum capricornutum), freshwater diatom (Navicula
pelliculosa), blue-green cyanobacteria (Anabeana flow-aquae), and marine
diatom (Skeletonema costatum).  Other outstanding non-target aquatic
plant toxicity tests are:  floating freshwater aquatic macrophyte
duckweed (Lemna gibba) – 850.4400 and rooted freshwater macrophyte
rice (Oryza sativa) – 850.4225 and 850.4250 (2 tests on seedling
emergence and vegetative vigor).  

II.	Risk Assessment and Characterization

	Naphthenate salts uses are classified as “indoor” with the
exception of the wood treatment uses.  An ecological risk assessment is
not typically conducted for “indoor” uses.  A risk assessment for
the wood preservative uses is conducted below using the toxicity values
from section I and estimated environmental concentrations (EECs)
calculated by modeling copper naphthenate leaching into a body of water
from a dock.  These values were used to develop risk quotients (RQs) and
compare them to levels of concern (LOCs) in section B below.  Modeling
was not conducted for zinc naphthenate, but environmental exposures are
assumed to be similar to those for copper naphthenate.

      A.        Environmental Fate Assessment Summary 

Copper naphthenate is very stable substance in water under aerobic and
abiotic conditions, with an estimated half-life of more than three
months.  It is highly to moderately immobile in soils with an estimated
Koc of over 3000.  It is not highly water soluble and has a low vapor
pressure (~ 10-4 mm Hg) and air/water partition coefficient (estimated
Henry Law Constant for copper naphthenate is ~ 9.804x 10-6).  Therefore
copper naphthenate is likely to evaporate from water surfaces as well as
contaminate surface water through soil run-off.  Copper naphthenate is
likely to persist in water and soils.  The estimated log Kow for copper
naphthenate is 4.1685, which indicates that copper naphthenate can
possibly bioaccumulate in aquatic organisms like fish.  The estimated
half-life in air is 8.858 hours (measured against the hydroxyl radical)
and it is not likely to be persistent in air.  A laboratory study on
southern yellow pine stakes has shown that copper naphthenate does leach
from pressure and surface treated wood.  

Zinc naphthenate, like copper naphthenate, is likely to be a stable
substance in water under aerobic and abiotic conditions, with an
estimated half-life of more than three months.  It is also likely to be
highly to moderately immobile in soils with an estimated Koc of over
3000. It is not highly water soluble and has a low vapor pressure (~
10-4 mm Hg) and air/water partition coefficient (estimated Henry Law
Constant for copper naphthenate is ~ 9.804x 10-6).  Therefore zinc
naphthenate, like copper naphthenate, is likely to evaporate from water
surfaces and contaminate surface water through soil run-off.  Zinc
naphthenate is also likely to persist in water and soils.  The estimated
log Kow for zinc naphthenate is possibly similar to that of copper
naphthenate (4.1685).  This indicates that zinc naphthenate can possibly
bioaccumulate in aquatic organisms like fish.  The estimated half-life
of copper naphthenate in air is 8.858 hours and zinc naphthenate is
likely to have a similar value and is not likely to be persistent in
air.  A laboratory study on southern yellow pine stakes has shown that
zinc naphthenate does leach from surface and pressure treated wood. 
Because of a high Koc  zinc naphthenate is likely to contaminate surface
soils around treated wood.

Considering the above, the following studies are required to better
determine the bioaccumulation potential of naphthenate salts and to
quantify leaching amounts from treated wood:  fish bioconcentration
study (850.1730); and aqueous leaching study (AWPA E11-06). 
Additionally, an environmental runoff monitoring study (guideline no.
none) is required unless wood preservative labels are modified to
include the restrictions outlined above.

B.	Environmental Exposure and Ecological Risk Assessment

Risk assessment integrates the results of the exposure and ecotoxicity
data to evaluate the likelihood of adverse ecological effects. One
method of integrating the results of exposure and ecotoxicity data is
called the quotient method.  For this method, risk quotients (RQs) are
calculated by dividing exposure estimates by ecotoxicity values, both
acute and chronic:  

       

           RQ = EXPOSURE/TOXICITY 

 

RQs are then compared to levels of concern (LOCs).  These LOCs are
criteria used by OPP to indicate potential risk to nontarget organisms
and the need to consider regulatory action.  The criteria indicate that
a pesticide used as directed has the potential to cause adverse effects
on nontarget organisms.  LOCs currently address the following risk
presumption categories: (1) acute - the potential for acute risk is
high, regulatory action may be warranted in addition to restricted use
classification; (2) acute restricted use - the potential for acute risk
is high, but this may be mitigated through restricted use
classification; (3) acute endangered species - the potential for acute
risk to endangered species is high, and regulatory action may be
warranted, and (4) chronic risk - the potential for chronic risk is
high, and regulatory action may be warranted, (5) non-endangered plant
risk – potential for effects in non-target plants, and (6) endangered
plant risk – potential for effects in endangered plants.   Currently,
EPA 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) LC50 (fish and birds), (2) LD50 (birds and
mammals), (3) EC50 (aquatic plants and aquatic invertebrates) and (4)
EC25 (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, along with the corresponding RQs and LOCs are
tabulated below.

Risk Presumptions for Terrestrial Animals

Risk Presumption	

RQ	

LOC

Birds and Wild Mammals

Acute Risk	

EEC1/LC50 or LD50/sqft2 or LD50/day3	

0.5

Acute Restricted Use	

EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 50 mg/kg)	

0.2

Acute Endangered Species	

EEC/LC50 or LD50/sqft or LD50/day 	

0.1

Chronic Risk	

EEC/NOAEC	

1

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

 2    mg/ft2             	3  mg of toxicant consumed/day

   LD50 * wt. of bird             	LD50 * wt. of bird  

Risk Presumptions for Aquatic Animals	 

Risk Presumption	

RQ 	

LOC

Acute Risk	

EEC1/LC50 or EC50	

0.5

Acute Restricted Use	

EEC/LC50 or EC50	

0.1

Acute Endangered Species	

EEC/LC50 or EC50	

0.05

Chronic Risk	

EEC/MATC2 or NOAEC	

1

 1  EEC = (ppm or ppb) in water

 2  MATC = maximum allowable toxicant concentration

Risk Presumptions for Plants	

	

Risk Presumption	

RQ	

LOC

Terrestrial and Semi-Aquatic Plants 

Acute Risk	

EEC/EC25	

1

Acute Endangered Species	

EEC/EC05 or NOAEC	

1

Aquatic Plants

Acute Risk	

EEC1/EC50	

1

Acute Endangered Species	

EEC/EC05 or NOAEC 	

1

EEC = (ppb/ppm) in water 

Maximum Expected Environmental Concentrations:	

	EPA calculated the leaching of copper naphthenate from a dock into
water.  It was assumed that 4% of the total applied copper naphthenate
would leach from the wood into the water.  An average retention rate of
0.03875 pounds per cubic foot was used.  The length and width of the
dock was assumed to be 30 meters and 10 meters, respectively and the
thickness of the wood was assumed to be 0.1 meters.  The number of poles
underneath the dock was assumed to be 18 and the dimensions of the poles
were assumed to be 2 meters (length) x 0.15 meters (width) x 0.15 meters
(height).  The poles were assumed to be 0.5 meters inserted into the
sediment.  Based on these specifications, copper naphthenate EECs were
calculated for water body sizes ranging from 1 acre foot to 24 acre
feet.  The highest EEC of 1.67 mg copper naphthenate per liter of water
was calculated for the smallest body of water (1 acre foot).  For a 6
foot deep water body, the EEC was calculated as 0.278 mg copper
naphthenate per liter of water.  For details on the calculations
conducted to arrive at this and other EECs as well as the uncertainties
and limitations of the calculations, consult Siroos Mostaghimi’s
4/27/2007 memo “Estimated Environmental Concentrations for Copper
Naphthenate from Treated Wood Used to Build Docks.”

Maximum Ecotoxicity Values:

In the toxicity tables in section I above, the toxicity of copper
naphthenate to bluegill sunfish (Lepomis macrochirus) is recorded.  The
LC50 value obtained in this study was 3.1 mg/L (MRID 424891-01).  The
EC50 value obtained in a study on the freshwater invertebrate (Daphnia
magna) was 0.34 mg/L (MRID 424891-03).  There were no acceptable acute
toxicity studies for estuarine and marine organisms nor were there any
acceptable chronic toxicity studies available for aquatic organisms. 
There were also no studies available for aquatic plants. Therefore, risk
to these species cannot be assessed.  

Acute Freshwater Fish LOC’s:

Comparing the maximum calculated Expected Environmental Concentration of
1.67 mg/L in one acre-inch of water to the toxicity found in the fish
acute study (3.1 mg/L), an RQ of 0.54 is obtained.  This is greater than
the LOCs for acute risks to aquatic animals (0.5) and acute endangered
species risks (0.05).  Therefore, there is the potential for copper
naphthenate to cause adverse effects to freshwater fish and these risks
may need to be mitigated.  The calculated EEC for a larger body of water
(6 acre feet) is 0.278 mg copper naphthenate per liter of water.  This
EEC brings the RQ for freshwater fish down to 0.09, which is lower than
all LOCs for aquatic organisms except for the endangered species LOC. 
However, as discussed below an endangered species effect determination
will not be made at this time.

Acute Freshwater Aquatic Invertebrate LOC’s:

Comparing the maximum calculated EEC to the toxicity value found in the
study on the freshwater invertebrate (0.34 mg/L), an RQ of 4.91 is
obtained.  This is greater than all LOCs for aquatic organisms. 
Therefore, there is the potential for copper naphthenate to cause
adverse effects to freshwater invertebrates and these risks may need to
be mitigated.  The calculated EEC for a larger body of water (6 acre
feet) is 0.278 mg copper naphthenate per liter of water.  This EEC
brings the RQ for the freshwater invertebrate down to 0.82 so the risks
to freshwater invertebrates remain.  However, as discussed below an
endangered species effect determination will not be made at this time.

Acute Aquatic Estuarine/Marine Species:

	Three acute estuarine/marine ecotoxicity studies are required (one
fish, one shrimp, one bi-valve), however, no data are available for
copper naphthenate.  This risk assessment is incomplete.

Chronic Aquatic Toxicity Studies:

	Chronic freshwater fish and invertebrate studies are triggered based on
acute toxicity.  No studies are available for copper naphthenate. 
Estuarine/marine chronic toxicity studies for fish and invertebrates are
reserved pending results of acute toxicity tests.  This risk assessment
is incomplete.

Plant Toxicity Studies:

	No aquatic or terrestrial plant toxicity studies are available for
copper naphthenate.  This risk assessment is incomplete.

Avian and Mammalian Species:

	Based on available avian toxicity data for copper naphthenate, the
various wood treatments are not expected to be acutely toxic.

Uncertainties and Limitations:

	Fate and Environmental Modeling:  There are a number of uncertainties
and limitations with this preliminary environmental risk assessment. 
Extrapolating risk conclusions from the pond scenario used in the
environmental modeling may either underestimate or overestimate
potential exposures and risks. Numerous uncertainties exist with the
modeling used since environmental properties are likely to be regionally
specific because of local hydrogeological conditions.  Further, any
alteration in water quality parameters may impact the environmental
behavior of the pesticide.  Additionally, there are pertinent data (wood
leaching, fish bioconcentration) lacking; such data would be useful in
refining this preliminary risk assessment.

	Toxicity Data:  This screening level risk assessment relies on selected
toxicity endpoints from, what is believed to be, the most sensitive
species tested, but it does not necessarily mean that the selected
toxicity endpoints reflect sensitivity of the most sensitive species
existing in a given environment.  Surrogates were used to predict
potential risks for various species, and data for several species are
lacking.  Submission of additional non-target organism data will refine
this screening level assessment.

	Stakeholder Modeling Efforts:  The American Chemistry Council (ACC)
Biocides Panel Copper Reregistration Task Force is presently developing
modeling pertinent to the wood preservative and roofing uses of various
copper products.  This modeling effort is intended to provide estimated
environmental exposures which can be used by the Agency to refine
environmental assessments.  Such data would be useful in refining this
screening level assessment.

      Endangered Species Considerations

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2),
requires all federal agencies to consult with the National Marine
Fisheries Service (NMFS) for marine and 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, and are considered to fall under a
“No Effect” determination.  The active ingredient uses of
naphthenate salts for material preservative uses fall into this
category.

	For the wood treatment uses, this preliminary analysis indicates that
there is a potential for naphthenate salts use to overlap with listed
species and that a more refined assessment is warranted, to include
direct, indirect and habitat effects.  The more refined assessment
should involve clear delineation of the action area associated with
proposed use of naphthenate salts 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.  The wood runoff label statement is expected to provide some level
of mitigation until such time as a full endangered species assessment is
possible.

Confirmatory Data Required To Support Wood Treatment Use:

	

Acute aquatic invertebrate study (850.1010) (zinc naphthenate),

Estuarine/marine fish acute study (850.1075) (both copper and zinc
naphthenate),

Estuarine/marine shrimp acute study (850.1035) (both copper and zinc
naphthenate),

Estuarine/marine mollusk acute study (850.1025) (both copper and zinc
naphthenate),   

Acute sediment toxicity to freshwater invertebrates (850.1735) (both
copper and zinc naphthenate),

Acute sediment toxicity to estuarine invertebrates (850.1740) (both
copper and zinc naphthenate),

Fish bioconcentration study – BCF (850.1730) (both copper and zinc
naphthenate),

Aquatic invertebrate (freshwater) life-cycle study (850.1300) (both
copper and zinc naphthenate),1

Fish early life-stage (freshwater) study (850.1400) (both copper and
zinc naphthenate),1

Fish early life-stage (estuarine/marine) study (850.1400) (both copper
and zinc naphthenate),1

Chronic mysid shrimp study (850.1350) (both copper and zinc
naphthenate),1

Freshwater green alga (850.5400) (both copper and zinc naphthenate),

Freshwater diatom (850.5400) (both copper and zinc naphthenate),

Blue-green cyanobacteria (850.5400) (both copper and zinc naphthenate),

Marine diatom (850.5400) (both copper and zinc naphthenate),

Freshwater floating macrophyte duckweed (850.4400) (both copper and zinc
naphthenate),

Freshwater rooted macrophyte rice seedling emergence (850.4225) (both
copper and zinc naphthenate),

Freshwater rooted macrophyte rice vegetative vigor (850.4250) (both
copper and zinc naphthenate),

Wood leaching study (AWPA E11-06) (both copper and zinc naphthenate),

Environmental runoff monitoring study (None) (both copper and zinc
naphthenate).  This test can be waived provided labels are amended as
outlined below for wood preservative labels,

Residues in honey/beeswax and toxicity of treated wood residues to bees
– combination of Guideline 860.1500 and 850.3030 (“Honey Bee
Toxicity of Residues on Foliage.”).  The toxicity portion of this
study is in lieu of the honeybee contact LD50 test 850.3020.  The
residue and toxicity test can be waived provided the label is amended to
prohibit the use of treated wood for beehive construction, with a
statement such as, “Wood treated with copper/zinc naphthenate shall
not be used in the construction of beehives.” (both copper and zinc
naphthenate).

 

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

Naphthenate salts labels must state:  

“This pesticide is toxic to aquatic invertebrates, shrimp, and
oysters/clams.”  (Note:  Estuarine organisms are added based on
freshwater toxicity.  Shrimp, oysters and clams should stay in the label
hazard statement until such time as data proves otherwise.)

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

Wood preservative labels must state:  

"Treated lumber must be stored under cover, indoors, or at least 100
feet from any pond, lake, stream, wetland, or river to prevent possible
runoff of the product into the waterway.  Treated lumber stored within
100 feet of a pond, lake, stream, wetland, or river must be either
covered with plastic or surrounded by a berm to prevent surface water
runoff into the nearby waterway.  If a berm or curb is used around the
site, it should consist of impermeable material (clay, asphalt,
concrete) and be of sufficient height to prevent runoff during heavy
rainfall events.”

“Wood treated with copper/zinc naphthenate shall not be used in the
construction of beehives.”  (Note:  If this statement is not added to
wood preservation labels, bee studies are required as noted above.) 

V.  REFERENCES

42348601  Campbell, S.; Lynn, S. (1992) Copper Naphthenate: An Acute
Oral Toxicity Study with the Northern Bobwhite: Lab Project Number:
324-101.  Unpublished study prepared by Wildlife International, Ltd.
32p.

42348602  Campbell, S.; Grimes, J.; Lynn, S. (1992) Copper Naphthenate:
Acute Avian Dietary Toxicity (LC50) in Bobwhite Quail: Lab Project
Number: 324-102.  Unpublished study prepared by Wildlife International,
Ltd. 45p.

42348603  Campbell, S.; Grimes, J.; Lynn, S. (1992) Copper Naphthenate:
Acute Avian Dietary Toxicity (LC50) in Mallard Ducks: Lab Project
Number: 324-103.  Unpublished study prepared by Wildlife International,
Ltd. 46p.

42348604  Campbell, S.; Lynn, S. (1992) Zinc Naphthenate: An Acute Oral
Toxicity Study with the Northern Bobwhite: Lab Project Number: 324-104. 
Unpublished study prepared by Wildlife International, Ltd. 32p.

42348605  Campbell, S.; Grimes, J.; Lynn, S. (1992) Zinc Naphthenate: A
Dietary LC50 Study with the Northern Bobwhite: Lab Project Number:
324-105.  Unpublished study prepared by Wildlife International, Ltd.
45p.

42348606  Campbell, S.; Grimes, J.; Lynn, S. (1992) Zinc Naphthenate: A
Dietary LC50 Study with the Mallard: Lab Project Number: 324-106. 
Unpublished study prepared by Wildlife International, Ltd. 46p.

42489101  Collins, M. (1992) Copper Naphthenate: Acute Toxicity to
Bluegill Sunfish (Lepomis macrochirus) under Static Renewal Conditions:
Final Report: Lab Project Number: 92-3-4147: 11582.0591.6107.100. 
Unpublished study prepared by Springborn Labs, Inc. 59p.

42489102  Collins, M. (1992) Zinc Naphthenate: Acute Toxicity to Rainbow
Trout (Oncorhynchus mykiss) under Static Conditions: Final Report: Lab
Project Number: 92-3-4154: 11582.0591.6104.103.  Unpublished study
prepared by Springborn Labs, Inc. 56p.

42489103  Collins, M. (1992) Copper Naphthenate: Acute Toxicity to
Daphnids (Daphnia magna) under Static Conditions: Final Report: Lab
Project Number: 92-2-4096: 11582.0591.6106.110.  Unpublished study
prepared by Springborn Labs, Inc. 58p

  Testing with the more sensitive species (freshwater or
estuarine/marine) based on acute toxicity test results is required.

  The following discussion concerns copper naphthenate.  However, the
Agency assumes that environmental exposures and risks of zinc
naphthenate are similar to those of copper naphthenate.

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