UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF

PREVENTION, PESTICIDES

  AND TOXIC SUBSTANCES

Date: July 12, 2007

MEMORANDUM

SUBJECT:	Naphthenate Salts: Preliminary Risk Assessment for Issuance of
the Reregistration Eligibility Decision (RED) Document.  PC Codes:
023102, 088301, 863508, 900436 and 025101.

FROM:	Timothy F. McMahon, Ph.D.

Senior Toxicologist/Risk Assessor

Antimicrobials Division (7510P)

And

Najm Shamim, Ph.D., Chemist

Regulatory Management Branch II

Siroos Mostaghimi, Ph.D., Biologist

Genevieve Angle, Biologist

Jonathan Chen, Ph.D., Toxicologist

Doreen Aviado, Biologist

Risk Assessment and Science Support Branch

Antimicrobials Division (7510P)

TO:	Kathryn Jakob, Chemical Review Manager

	Diane Isbell, Team Leader

	Mark Hartman, Branch Chief

	Regulatory Management Branch II

	Antimicrobials Division (7510P)

	Attached is the Naphthenate Salts preliminary risk assessment for the
purpose of issuance of the reregistration eligibility decision (RED).

Naphthenate Salts

Preliminary Risk Assessment

Office of Pesticides Program

Antimicrobials Division

U.S. Environmental Protection Agency

2777 South Crystal Drive

Arlington, VA 22202

Date: May 31, 2007

TABLE OF CONTENTS

1.0	EXECUTIVE
SUMMARY………………………………………………………
……………….....3

2.0	PHYSICAL AND CHEMICAL
PROPERTIES……………………………………………….....10

3.0	HAZARD
CHARACTERIZATION……………………………………….………
……………....11

   	 3.1	HAZARD
PROFILE………………………………………………………
……………......11

    	 3.2	FQPA
CONSIDERATIONS…………………………………………………
…………......13

   	 3.3	DOSE-RESPONSE
ASSESSMENT……………………………………….……..........
......14

     	 3.4	ENDOCRINE
DISRUPTION……………………………………………………
……........15

.

4.0	EXPOSURE ASSESSMENT AND
CHARACTERIZATION………………………………............16

     	 4.1	SUMMARY OF REGISTERED
USES....................................................................
.............16

    	 4.2	DIETARY EXPOSURE AND
RISK....................................................................
.................17

     	 4.3	DRINKING WATER EXPOSURES AND
RISKS...................................................... ........17

    	 4.4	RESIDENTIAL EXPOSURES/RISK
PATHWAYS.............................................................17

5.0	AGGREGATE RISK ASSESSMENT AND
CHARACTERIZATION……………………….....27

	5.1	ACUTE AND CHRONIC DIETARY AGGREGATE
RISK................................................27

	5.2	SHORT-TERM AGGREGATE
RISKS...................................................................
..............27

6.0	CUMULATIVE EXPOSURE AND
RISK……………………………………………………........
29

7.0	OCCUPATIONAL EXPOSURE
ASSESSMENT……………………………………………........29

     	 7.1	SUMMARY OF REGISTERED
USES....................................................................
..............29

     	 7.2	OCCUPATIONAL HANDLER
EXPOSURES...............................................................
.......32

     	 7.3	OCCUPATIONAL POST-APPLICATION
EXPOSURES....................................................36

	 7.4	WOOD
PRESERVATION............................................................
..........................................36

     	 7.5	DATA
LIMITATIONS/UNCERTAINTIES...............................................
............................47

8.0
ENVIRONMENTALRISKS.……………………………………………..
.........................................49

    	 8.1	ECOLOGICAL
HAZARD..................................................................
.....................................49

    	 8.2	ENVIRONMENTAL FATE
ASSESSMENT..............................................................
............57

    	 8.3	ENVIRONMENTAL EXPOSURE AND ECOLOGICAL RISK
ASSESSMENT.................58

    	 8.4	ENDANGERED SPECIES
CONSIDERATIONS..........................................................
.........58

	 8.5	DATA UNCERTAINTIES AND
LIMITATIONS.............................................................
.....59

9.0	INDCIDENT
REPORTS………………………………………………………
………………..........60

10.0
REFERENCES..............................................................
........................................................................
61

11.0	APPENDIX
A.……………………………………………………………
……………………............68

12.0	APPENDIX
B.......................................................................
..................................................................75

13.0	APPENDIX
C.......................................................................
..................................................................77

1.0	EXECUTIVE SUMMARY

	The naphthenate salts (copper and zinc naphthenate) are both salts of
naphthenic acid, which is essentially a mixture of cyclic carboxylic
acids, predominantly cyclopentane derivatives with an average molecular
weight of 200-300 (BIBRA, 1999).  The mixture may also contain some
cyclic hydrocarbons (BIBRA, 1999). Naphthenate salts are
microbiocide/microbiostat, miticide, fungicide, insecticide, algaecide
and herbicide/terrestrial chemicals. Use sites for copper naphthenate
include pressure treatment and non –pressure treatment of wood for
exterior uses (residential and non-residential), wood used in contact
with fresh or salt water, and exterior wood exposed to moisture or
weather. Copper naphthenate is also used in brush, dip, roller, and low
pressure spray applications for the same uses listed above, and in
addition is used for greenhouse and horticultural uses (non-food
applications including wooden seedling trays, plant and flower boxes for
ornamental plantings, trellises, arbors, greenhouse benches, and nursery
flats). Application by occupational applicators only includes  brush,
dip, roller, and low pressure spray to beverage cases, baskets, tents,
awnings, tarpaulins, canvas products, nets [except fishnets], ropes,
cordage, lumber for ammunition boxes, other boxes, crates, and
miscellaneous non –food contact containers, truck and boat covers,
non-rubber fabrics, and burlap. Copper naphthenate is also used as a
remedial treatment for standing wood utility poles, mine timbers, bridge
timbers, and cross-ties and stakes.

	Zinc naphthenate use sites are the same as for copper naphthenate but
do not include remedial treatments or to beverage cases, etc. as listed
for copper naphthenate. There is also one tolerance exemption for
residues of copper naphthenate when used in accordance with good
agricultural practice as an inert ingredient in pesticide formulations
applied to growing crops only (40 CFR 180.920). No more than 2.5% copper
naphthenate can be present, and products containing copper naphthenate
can only be applied before the edible portions of plants begin to form.

Hazard Characterization

The acute toxicity database for Copper naphthenate is incomplete.  There
are no acceptable acute toxicity studies for the technical grade
(80-89%) active ingredient in the toxicology database. The highest
concentration of active ingredient that was tested in acceptable acute
toxicity studies was 45.4% a.i. Based on testing of a single dose of 501
mg/kg (MRID 266172), a toxicity category III was assigned for acute oral
toxicity. Toxicity categories of III and IV were assigned for acute
dermal and acute inhalation toxicity but the studies were considered
unacceptable. Skin and eye irritation testing of copper naphthenate at
45.4% showed the compound to be a severe irritant in both cases, with a
toxicity category of I assigned for skin and eye irritation effects
(MRID 266172). Copper naphthenate is not a dermal sensitizer.

	In contrast to copper naphthenate, there are acceptable acute toxicity
data available for the technical grade active (60%) of zinc naphthenate.
For acute oral toxicity of zinc naphthenate (60%), a toxicity category
IV has been assigned based on a LC50 greater than 5000 mg/kg (MRID
244277). A toxicity category of III was assigned for acute dermal
toxicity based on the LD50 for males and females being greater than 2000
mg/kg (MRID 244277). Acute inhalation toxicity was assigned a catefory
of IV but the study was found to be unacceptable. Skin and eye
irritation testing of zinc naphthenate at 60% showed the compound to be
moderate to severe and slight irritants respectively, with a toxicity
category of (II, skin) and (III, eye)  assigned for skin and eye
irritation effects (MRID 244277).   In a dermal sensitization study with
zinc naphthenate (60%), the material appeared to be a primary skin
irritant and a possible sensitizing agent (MRID 244277).

	Subchronic (repeat dose) testing of copper naphthenate administered by
the dermal route for 90 days (MRID 41676101) showed no evidence of
systemic toxicity up to and including a limit dose of 1000 mg/kg, but
showed evidence of dermal irritation at a dose of 300 mg/kg/day.  Zinc
naphthenate administered by the dermal route for 90 days (MRID 41615001)
showed systemic toxicity at a dose of 300 mg/kg/day, while dermal
irritation was observed at all dose levels (100 mg/kg/day and above).

In developmental toxicity testing of copper naphthenate (MRIDs
41615101), maternal toxicity was shown in rats at doses of 100 and 300
mg/kg by decreases in body weight and food consumption. In developmental
toxicity testing of zinc naphthenate in rats (MRID 41615002), the only
observed clinical sign of maternal toxicity was a dose-related increase
in staining around the mouth and anogenital area at doses of 250 and 500
mg/kg/day.  There was no evidence of developmental toxicity observed at
any dose level for both copper and zinc naphthenate.

There were no chronic toxicity or carcinogenicity data submitted for
either copper or zinc naphthenate.

The Agency considers all of the submitted mutagenicity studies to be
unacceptable, but upgradable, if the test material purity is provided
for these studies. In the L5178Y TK+/- mouse lymphoma mutagenesis assay,
both copper and zinc naphthenate caused an increase in mutant frequency
in the presence of microsomal S9.  In the chromosomal aberration test
using Chinese hamster ovary cells, copper naphthenate caused no increase
in mitotic index at any of the concentrations tested and no significant
increase in CHO cells with aberrations at any of the concentrations
tested. Zinc naphthenate however, caused an increase in chromosomal
aberrations with increasing concentrations. In the unscheduled DNA
assay, both copper and zinc naphthenate did not induce an increase in
UDS in primary rat hepatocytes at any concentration tested.

There were no data submitted on neurotoxicity of either copper or zinc
naphthenate.

Dose-Response Assessment

For acute and chronic dietary risk assessments, no appropriate endpoints
were identified that represent a single dose effect.  Therefore, these
risk assessments are not required.

	For short-term (ST) (1-30 days) and intermediate-term (1-6 months)
incidental oral risk assessments, a maternal NOAEL of 30 mg/kg/day was
selected based on decreased body weight and food consumption at a dose
of 100 mg/kg/day in a developmental toxicity study of copper naphthenate
in the rat (MRID 41615101). An uncertainty factor of 100 was assigned
(10x inter-species extrapolation, 10x intra-species variation) in this
case.

	For short-term (1-30 days) dermal risk assessment, a LOAEL of 100
mg/kg/day was selected based on erythema, edema, and desquamation at a
dose of 100 mg/kg/day in a 90-day dermal toxicity study of zinc
naphthenate in the rabbit (MRID 41515001). An uncertainty factor of 300
(10x inter-species extrapolation, 10x intra-species variation, 3x for
use of LOAEL) was assigned in this case.

	For intermediate-term dermal risk assessment, a NOAEL of 100 mg/kg/day
was selected based on reductions in body weight gain observed at a dose
of 300 mg/kg/day in a 90-day dermal toxicity study of zinc naphthenate
(MRID 41515001). An uncertainty factor of 100 (10x inter-species
extrapolation, 10x intra-species variation) was assigned in this case.

	For inhalation risk assessments (all exposures), a NOAEL of 30
mg/kg/day was selected based on decreased maternal body weight and food
consumption at  a dose of 100 mg/kg/day in a developmental toxicity
study in the rat (MRID 41615101). An uncertainty factor of 1000 (10x
inter-species extrapolation, 10x intra-species variation, 10x
route-extrapolation) was applied in this case.

FQPA Considerations

	FQPA considerations are not applicable to copper and zinc naphthenate.
There are no food use tolerances for these chemicals, and indirect food
contact is not expected from the current uses of these chemicals.

Dietary Exposure and Risk

	There is neither direct nor indirect food uses associated with
Copper/Zinc Naphthenate active ingredients.  There is however, one
tolerance exemption for residues of Copper Naphthenate when used in
accordance with good agricultural practices as an inert ingredient in
pesticide formulations applied to growing crops only [(40 CFR 180.920) -
No more than 2.5% Copper Naphthenate can be present, and products
containing Copper Naphthenate can only be applied before the edible
portions of plants begin to form.].

Drinking Water Exposure and Risk

There are no potable water treatment uses for registered products
containing Copper/Zinc Naphthenates, nor are effluents of this chemical
anticipated to impact fresh water environments through proper product
use.

Residential Handler Exposure and Risk

	Residential handler dermal and inhalation exposure scenarios for most
homeowner applications of Naphthenate Salts products are believed to be
best represented by the short-term exposures (1 to 30 days). Residential
handlers using wood preservative coatings may have inhalation exposures
to aerosol particulates during applications using a low-pressure sprayer
or dermal exposure while using a brush/roller. The calculated ST MOEs
were above the target inhalation MOE of 1,000 for both scenarios. The
dermal MOEs were both below the ST MOE target of 300, denoting potential
dermal irritation concern.

Residential Post-application Exposure and Risk

	Representative post-application scenarios assessed include contacting
treated textiles (adult/child dermal and incidental oral exposure to
children) and contacting treated wood (adult/child dermal and incidental
oral exposures to children). Naphthenate Salts have a relatively low
vapor pressure therefore post-application inhalation exposures were not
assessed.

	For dermal exposure to adults and toddlers from treated textiles, the
MOEs were below the short-term target of 300 for both scenarios using
transfer factors. The MOEs were 10 at 100% and 200 at 5%, indicating
potential dermal irritation concerns.  For incidental oral exposure to
children, the ST MOE value was 10, which is below the ST target MOE of
100, indicating potential risk concern. For dermal contact with treated
wood the dermal ST MOEs were well above the target MOE (i.e., 300) for
all test subjects. However, considerable uncertainties in the assessment
(eight-hour work shift, surface spray applications, and monitored
shortly after application) require a confirmatory surface wipe study on
pressure treated wood to refine the skin concentration/exposure for
children playing on treated structures. The estimated short-term MOE for
the hand-to-mouth exposure (incidental oral excposure) is above the
target MOE of 100 (as 1,100) and therefore not of concern.

Aggregate Exposure and Risk

	In order for a pesticide registration to continue, it must be shown
“that there is reasonable certainty that no harm will result from
aggregate exposure to pesticide chemical residue, including all
anticipated dietary exposures and other exposures for which there are
reliable information.”  Aggregate exposure is the total exposure to a
single chemical (or its residues) that may occur from dietary (i.e.,
food and drinking water), residential, and other non-occupational
sources, and from all known or plausible exposure routes (oral, dermal,
and inhalation).

Short-Term Aggregate Exposures and Risks

	The following lists summarize all of the potential non-dietary sources
of Naphthenate Salts exposures for adults and children in residential
settings:

Adult Naphthenate Salts exposure sources:

Applying wood preservative/water repellent coatings in residential
settings;

Applying materials preservatives to cellulose-based fibers/textiles in
residential settings;

Post-application exposures to treated outdoor-use wood;

Post-application exposures to treated outdoor-use textiles.

Child Naphthenate Salts exposure sources:

Post-application exposure to treated outdoor-use wood;

Post-application exposures to treated outdoor-use textiles.

Scenarios considered for the aggregate assessment include: short-term
inhalation exposure by adult handlers and short-term dermal and
incidental oral post-application exposure by children from contact with
treated lumber.

Because the endpoints for the ST dermal and incidental oral routes of
exposure were based on route-specific studies resulting in different
effects, separate route-specific aggregate assessment are appropriate.
However, only one exposure scenario was identified for each route of
exposure.  Accordingly, evaluation of aggregate risk as   outlined in
the OPP guidance for aggregate risk assessment (September 1, 2000,
Standard Operating Procedure (SOP) for Incorporating Screening Level
Estimates of Drinking Water Exposure into Aggregate Risk Assessments) is
not required.

Occupational Exposure

Occupational Handler Exposures

	The occupational handler scenarios included in Table 7.1 were assessed
to determine dermal and inhalation exposures. Calculated MOEs were below
the target MOEs of 100 for IT dermal and 1,000 for ST/IT/LT inhalation
for the following scenarios listed.  It should be noted that for MOEs
below 1,000, the Agency may request a confirmatory inhalation toxicity
study to refine the potential risks since the current inhalation
endpoint is based on an oral NOAEL.

Dermal:

Preservation of textiles, low-pressure sprayer:  MOE = 3 at baseline
dermal;

Preservation of textiles, brush/roller:  MOE = 4 at baseline and 33 with
glove PPE;

Preservation of textiles, liquid pour:  MOE = < 1 at baseline and 50
with glove PPE;

Preservation of textiles, liquid pump: MOE = 14 at baseline;

General preservation of wood, brush/roller: MOE = 4 at baseline, 25 with
glove PPE;

General preservation of wood, airless sprayer: MOE = 2 at baseline, 5
for glove PPE;

General preservation of wood, low-pressure sprayer:  MOE = 3 at
baseline;

Application to in-service utility poles, brush: MOE = 5 at baseline, 33
for glove PPE.

Inhalation:

Preservation of textiles, brush/roller:  MOE = 750 without respirator
PPE;

Preservation of textiles, liquid pour:   MOE = 600 without respirator
PPE;

General preservation of wood, brush/roller:  MOE = 700 without
respirator PPE;

General preservation of wood, airless sprayer: MOE = 23 without
respirator PPE and 230 with respirator use;

Application to in-service utility poles, brush: MOE = 880 without
respirator PPE.

Occupational Post-application Exposures

            Except for the post-application scenarios assessed for wood
preservatives, occupational post-application exposures are assumed to be
negligible.

Wood Preservation

Copper and Zinc Naphthenates are used industrially as a wood
preservative in treating wood for exterior uses (above-ground,
ground-contact, below-ground, and fresh or salt water). The formulated
EP preservatives are usually supplied as solvent, water or oil-based
solutions having a guaranteed metal content. Registered uses for
Naphthenate Salts include wood preservative treatments as wood surface
coatings [e.g., wood protection treatment (including as water
repellents) applied via brush, roller, or spray] and impregnation into
wood via non-pressure (e.g., non-pressure dipping/immersion) and
pressure techniques (vacuum/full-cell).

For wood preservation, the exposures were assessed as non-pressure and
pressure treatment related scenarios. For the non-pressure treatment
exposure, assessments were carried out based on worker function:
Handler: Blender/spray operators, chemical operators, diptank operators
and Post-application: Graders, trim saw operators, millwrights, clean up
crews, construction workers.

	The MOEs for the blender/spray operators adding the preservative to the
wood slurry scenario were above the Agency targets of 100 for IT dermal
(as 450) and 1000 for ST/IT/LT inhalation (as 2,100), denoting no
exposure risks of concern.  However, for the generic non-pressure
treatment mixer/loader scenario, both dermal and inhalation MOEs pose
exposure risk concerns.  The dermal IT MOE was below the target of 100
(as 25) and the inhalation ST/IT/LT MOE was below the target of 1000 (as
120). Therefore, registrant input is needed to clarify use rate and
quantity treated. Also, a confirmatory inhalation toxicity study may be
warranted based on the results of this assessment. For diptank operators
the IT dermal MOEs were below the Agency target of 100 (ranging from
70-90 for 32% and 25% a.i. products respectively) and therefore denote
potential dermal risk concerns.  The inhalation ST/IT/LT MOEs were above
the Agency target of 1,000, and not of concern.  Therefore, a
confirmatory inhalation toxicity study is not warranted based on the
results of this exposure scenario.

Dermal and inhalation MOEs for chemical operators, graders, millwrights,
clean-up crews, and trim saw operators were not of concern. The
inhalation MOEs are above the target MOE of 1,000 and therefore a
confirmatory inhalation toxicity study is not warranted based on the
results of this assessment.  Also, the dermal MOEs are above the target
MOE of 100 for IT durations assessed. There was insufficient data to
estimate the amount of exposure associated with construction workers who
install treated wood.

	For the pressure treatment scenarios (Handler and Post-Application),
chemical-specific exposure data are not available on Naphthenate Salts
for assessment of pressure treatment exposure.  Therefore, the
assessment relies on surrogate Chromated Copper Arsenate (CCA) data
(ACC, 2002) and was based on the approach used in a previous Agency
exposure assessment (USEPA, 2003). Dermal and inhalation exposures for
pressure treatment uses are derived from information in the exposure
study sponsored by the American Chemistry Council (2002) entitled
“Assessment of Potential Inhalation and Dermal Exposure Associated
with Pressure Treatment of Wood with Arsenical Wood Products” (ACC,
2002). Assessments were conducted based on worker function: Handler:
Treatment operator (TO), Treatment assistant (TA); Post-application:
Tram setter, stacker operator, loader operator, supervisor, test borer,
tallyman. The calculated IT dermal MOEs for both the treatment operator
handler (MOE = 25) and post-application workers (MOE = 70) were below
the Agency target MOE of 100 and therefore represent potential risks of
concern.  The ST/IT/LT inhalation MOEs for all scenarios are above the
target MOE of 1,000 and not of concern.  In addition, because the MOE is
greater than 1,000, a confirmatory inhalation toxicity study is not
warranted based on the screening-level results.

Ecological/Environmental Risk

	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.

Copper and zinc naphthenate are very stable substance in water under
aerobic and abiotic conditions, with an estimated half-life of more than
three months.  Both naphthenates are highly to moderately immobile in
soils with an estimated Koc of over 3000.  They are not highly water
soluble and have a high 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 and zinc naphthenate
are likely to evaporate from water surfaces as well as contaminate
surface water through soil run-off.  They are also likely to persist in
water and soils.  The estimated log Kow for copper naphthenate and zinc
naphthenate is 4.1685, which indicates that these compounds can possibly
bioaccumulate in aquatic organisms like fish.  Their estimated half-life
in air is 8.858 hours (measured against the hydroxyl radical) and are
not likely to be persistent in air.  A laboratory study on southern
yellow pine stakes has shown that both copper and zinc naphthenate do
leach from pressure and surface treated wood. Because of a high Koc
zinc naphthenate is likely to contaminate surface soils around treated
wood.

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.

Endangered Species

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.

Incident Reports

	Some incidences associated with exposure to end-use products containing
copper and/or zinc naphthenates have been reported. Itchy rashes are the
primary reported complaints through dermal exposure. Inhalation of
vapors of pesticides containing copper naphthenate have been reported to
cause nausea, head ache, dizziness, sore throat, dry throat, chest
tightness and coughing. The most common symptoms reported for cases of
ocular exposure were eye irritation/burning.  Eye pain and swelling of
eyes also been reported in some cases. No exposure incidences associated
with oral exposure have been reported.

2.0	PHYSICAL AND CHEMICAL PROPERTIES

Table 2.1.  Physical/Chemical Properties of Copper/Zinc Naphthenates
(TGAIs)

Parameter	Copper Naphthenate	Zinc Naphthenate

Molecular Weight	Average ( 550

Variable between 400-750

Variable between 400-750

Color/Odor	Green-blue /Burnt and hydrocarbon-like odor	Light Brown/
Hydrocarbon-like odor

Physical State	TGAI is a solid amorphous glass at 25 o C;         MUP is
a viscous liquid at 25 o C          	TGAI appears solid;

 MUP appears to be a viscous liquid at 25 o C

Specific Gravity (Relative Density)	0.99-1.055 g/ml

	0.8-1.02 g/ml

Stability	Stable under normal conditions and elevated temperatures.
TGAI is non-flammable at 60 o C and non-explosive. 	Stable at ambient
temperatures (22± 2 o C) and elevated temperatures (53-55 o C) for 14
days (based on data from a 14-day study only).  TGAI  is non-flammable
at 60 o C and non-explosive.

Melting Point	Average ( 102 o C 	----

Boiling Point	TGAI is a non-volatile salt (decomposes at around 257 o
C); MUP boiling point 121 o C.	----

Water Solubility	4.6899 mg/L (ppm) at 25 o C

(practically insoluble in water)         	15-80 ppm (mg/L) at 25 o C

(low solubility in water)

Solvent Solubility	Highly soluble in organic solvents; more soluble in
non-polar organics than polar organics.	Highly soluble in organic
solvents; more soluble in non-polar organics than polar organics.

Kow	4.1

	1.0 - 1.2

Vapor Pressure (VP)	1.28 x 10-4 mm Hg at  25 o C

 (Assumed to be of low volatility.)

[Note: Less than 133 mPa  at 100ºC (based on solid form)] a	1.0 x 10-5
mm Hg at  25 o C

(Assumed to be non-volatile.)

TGAI = Technical grade active ingredient; MUP = Manufacturing-use
product

Source: Certain data presented in Tables 1.1 and 1.2 were taken from the
following Agency review memoranda from A. Najm Shamim, PhD., Chemist,
AD, prepared in support of the Naphthenate Salts RED: “Data Evaluation
Records (DER) for the Product Chemistry of Copper Naphthenate”, dated
November 8, 2006, and “Data Evaluation Records (DER) for the Product
Chemistry of Zinc Naphthenate”, dated February 9, 2007.  Also, input
provided from the Naphthenate Salts Research Task Force.

a  Data are from the Hazardous Substances Data Bank (HSDB 2007

3.0	HAZARD CHARACTERIZATION

	3.1	Hazard Profile

	The naphthenate salts (copper and zinc naphthenate) are both salts of
naphthenic acid, which is essentially a mixture of cyclic carboxylic
acids, predominantly cyclopentane derivatives with an average molecular
weight of 200-300 (BIBRA, 1999).  The mixture may also contain some
cyclic hydrocarbons (BIBRA, 1999).  The naphthenate salts are considered
together for hazard characterization.  The presence of a zinc or copper
ion does not have a significant influence on the mammalian toxicity of
naphthenic acid.

	The acute toxicity database for Copper naphthenate is incomplete. There
are no acceptable acute toxicity studies for the technical grade
(80-89%) active ingredient in the toxicology database. The highest
concentration of active ingredient that was tested in acceptable acute
toxicity studies was 45.4% a.i. In an acute oral toxicity study with
copper naphthenate (45.4%), a toxicity category III was assigned based
on testing of a single dose of 501 mg/kg (MRID 266172). A toxicity
category of III was also assigned for acute dermal toxicity testing of
copper naphthenate but the submitted study was not acceptable (HED
document number 008158). Acute inhalation toxicity testing of 48% and
58% a.i. copper naphthenate (HED document number 008158) indicated a
toxicity category of IV, but the studies were unacceptable. Skin and eye
irritation testing of copper naphthenate at 45.4% showed the compound to
be a severe irritant in both cases, with a toxicity category of I
assigned for skin and eye irritation effects (MRID 266172).  Dermal
sensitization studies on copper naphthenate from the BIBRA Toxicity
profile (1999) indicate that copper naphthenate is not a dermal
sensitizer; there is no acceptable dermal sensitization data available
to the Agency on the technical grade of the a.i., although the available
data also indicate no sensitization potential.

	In contrast to copper naphthenate, there are acceptable acute toxicity
data available for the technical grade active (60%) of zinc naphthenate.
A battery of tests (acute oral, dermal, inhalation, primary eye, primary
skin, and dermal sensitization) was conducted using 60% a.i. zinc
naphthenate (MRID 244277). With the exception of an acute inhalation
study, acute oral, acute dermal, skin irritation, eye irritation and
dermal sensitization studies were considered acceptable. In an acute
oral toxicity study with zinc naphthenate (60%), a toxicity category IV
was assigned based on a LC50 greater than 5000 mg/kg (MRID 244277). A
toxicity category of III was also assigned for acute dermal toxicity
testing of zinc naphthenate with a LD50 for males and females greater
than 2000 mg/kg (MRID 244277). Acute inhalation toxicity testing of 60%
a.i. zinc naphthenate (MRID 244277) indicated a toxicity category of IV
with a LC50 greater than 11.6 mg/L over a 4 hour exposure period, but
the study was unacceptable. Skin and eye irritation testing of zinc
naphthenate at 60% showed the compound to be moderate to severe and
slight irritants respectively, with a toxicity category of (II, skin)
and (III, eye)  assigned for skin and eye irritation effects (MRID
244277). In a dermal sensitization study with zinc naphthenate (60%),
the material appeared to be a primary skin irritant and a possible
sensitizing agent (MRID 244277).

	In subchronic (repeat dose) testing, copper naphthenate administered by
the dermal route for 90 days (MRID 41676101) showed no evidence of
systemic toxicity up to and including a limit dose of 1000 mg/kg, but
showed evidence of dermal irritation at a dose of 300 mg/kg/day. Zinc
naphthenate administered by the dermal route for 90 days (MRID 41615001)
showed systemic toxicity at a dose of 300 mg/kg/day, while dermal
irritation was observed at all dose levels (100 mg/kg/day and above).

In developmental toxicity testing of copper naphthenate (MRIDs
41615101), maternal toxicity was shown in rats at doses of 100 and 300
mg/kg by decreases in body weight and food consumption.  There was no
evidence of developmental toxicity in this study at any dose.   In a
second developmental toxicity study conducted with zinc naphthenate in
rats (MRID 41615002), the only observed clinical sign of maternal
toxicity was a dose-related increase in staining around the mouth and
anogenital area at doses of  250 and 500 mg/kg/day.  There was no
evidence of developmental toxicity at any dose level in this study.  In
another study conducted by the United States Army (Angerhofer, 1991)
zinc naphthenate was tested up to 938 mg/kg/day  in rats with increased
resorptions and decreased fetal body weight observed at this dose, which
is close to a limit dose (i.e. 1000 mg/kg/day) for such studies and is
not considered toxicologically significant based on the magnitude of the
dose at which these effects were observed.

	There were no reproductive or carcinogenicity submitted for either
copper or zinc naphthenate.  Data were located on a 2-generation
reproductive toxicity test performed by the U.S. Army (Michie, M.W. et
al., 1988) in which zinc naphthenate (97 % a.i.) at dietary
concentrations of 0, 500, 1000, and 5000 ppm was fed to groups of
parental Sprague-Dawley rats (30 rats/sex/dose).  Toxicity in parental
animals was observed at 5000 ppm and consisted of: clinical signs
(lethargy in P males); decreased body weight in P and F1 males and
females; and nephrosis and tubular regeneration of the kidneys in P and
F1 males.  Offspring toxicity was observed at 5000 ppm and consisted of
decreased litter and pup weight at weaning for both the F1 and F2
generations. There was no evidence of reproductive toxicity in this
study.

 Mutagenicity studies were submitted for copper naphthenate and included
a mouse lymphoma assay (MRID 41402502), chromosome aberration test (MRID
41402503) and an unscheduled DNA synthesis (UDS) study (MRID 41402504).
In the L5178Y TK+/- mouse lymphoma mutagenesis assay, copper naphthenate
caused an increase in mutant frequency in the presence of microsomal S9.
In the chromosomal aberration test using Chinese hamster ovary cells,
copper naphthenate caused no increase in mitotic index at any
Mutagenicity studies were submitted for zinc naphthenate and included a
mouse lymphoma assay (MRID 41400701), chromosome aberration test (MRID
41400702) and an unscheduled DNA synthesis (UDS) study (MRID 41400703).
In the L5178Y TK+/- frequency in the

presence of microsomal S9. There was also a greater increase in small
colonies versus large

colonies with exposure to zinc naphthenate as opposed to copper
naphthenate exposure. In the chrosomal aberration test using Chinese
hamster ovary cells, zinc naphthenate caused an increase in chromosomal
aberrations with increasing concentrations of zinc naphthenate.  In the
unscheduled DNA assay, zinc naphthenate did not induce an increase in
UDS in primary rat hepatocytes at any concentration tested.

Acute Toxicity

	Adequacy of database for Acute Toxicity:  The acute toxicity database
for copper naphthenate is incomplete. There are no studies available on
the technical grade active ingredient for copper naphthenate. In
contrast, the acute toxicity database for zinc naphthenate technical is
complete. Copper naphthenate tested at 45.4% (or other %) a.i.has a
moderate order of acute toxicity via the oral, dermal and inhalation
routes of exposure (Toxicity Category III).  For dermal irritation,
copper naphthenate also has a moderate order of acute toxicity (Toxicity
Category III). Copper naphthenate is neither a significant eye irritant
or dermal sensitizer. Zinc naphthenate has a low to moderate order of
acute toxicity via the oral, dermal and inhalation routes of exposure
(Toxicity Category IV, III and IV, respectively). For dermal irritation,
zinc naphthenate has a moderate to severe order of acute toxicity
(Toxicity Category II). Zinc naphthenate is a possible dermal
sensitizer.

The acute toxicity data for copper and zinc naphthenate is summarized
below in Table 3.1.

Table 3.1 Acute Toxicity Profile for Copper/Zinc Naphthenate

Guideline Number	Study Type/Test substance (% a.i.)	MRID Number/

Citation	Results	Toxicity Category

870.1100

(§81-1)	Acute Oral- Rat

purity 45.4% -copper naphthenate	00266172	LD50 > 501 mg/kg	III

870.110

(§81-1)	Acute Oral- Rat

purity 58% -copper naphthenate	433342402	Not determined	N/A

870.1100

(§81-1)	Acute Oral- Rat

purity 60%- zinc naphthenate	00244277	LD50 > 2000 mg/kg	IV

870.1200

(§81-2)	Acute Dermal- Rabbit

purity not determined – copper naphthenate	41140710	LD50 > 2000 mg/kg
III

870.1200

(§81-2)	Acute Dermal- Rabbit

Purity 60%-zinc naphthenate	00244277	LD50 > 2000 mg/kg	III

870.1300

(§81-3)	Acute Inhalation- Rabbit

Purity technical- copper naphthenate	41486301	LC50 > 2.966 mg/L	III

870.1300

(§81-3)	Acute Inhalation- Rabbit

Purity 60%- zinc naphthenate	00244277	LC50 > 11.6 mg/L	IV

870.2400

(§81-4)	Primary Eye Irritation- Rabbit purity 80% -copper naphthenate
00260891	Redness cleared on day 4	III

870.2400

(§81-4)	Primary Eye Irritation- Guinea pig purity 60% -zinc naphthenate
00244277	Redness cleared on day 2	III

870.2500

(§81-5)	Primary Dermal Irritation- Rabbit

purity technical –copper naphthenate	41140710	Moderate Irritant	III

870.2500

(§81-5)	Primary Dermal Irritation- Rabbit

60% -zinc naphthenate	00244277	Moderate to severe Irritant	II

870.2600

(§81-6)	Dermal Sensitization - Guinea pig

purity 58 % - copper naphthenate	41140710	Not a sensitizer.	No

870.2600

(§81-6)	Dermal Sensitization - Guinea pig

purity 60 % - zinc naphthenate	00244277	Primary skin irritant/possible
sensitizing agent	No

3.2	FQPA Considerations

	FQPA considerations are not applicable to copper and zinc naphthente.
There are no food use tolerances for these chemicals, and indirect food
contact is not expected from the current uses of these chemicals.

3.3	Dose-Response Assessment

		3.3.1	Summary of toxicology endpoint selection for Naphthenate Salts
in Human Risk Assessment. Table 3.2

Table 3.2.  Naphthenate Salts (Copper, Zinc) for Use in Human Risk
Assessment

Exposure

Scenario	Dose (mg/kg/day) used in risk assessment

UF	Special FQPA SF and Level of Concern for Risk Assessment	Study and
Toxicological Effects

Dietary Risk Assessments

Acute Dietary

(general population and females 13-49)		No appropriate endpoints were
identified that represent a single dose effect.  Therefore, this risk
assessment is not required.

Chronic Dietary

	No appropriate endpoints were identified that represent a single dose
effect.  Therefore, this risk assessment is not required.

Non-Dietary Risk Assessments

Incidental Oral

Short–Term

(1 - 30 Days)

 	NOAEL = 30 mg/kg/day

 	Target MOE= 100 (10x inter-species extrapolation, 10x intra-species
variation)

	Developmental Toxicity – Rat (Copper Naphthenate)

 MRID 41615101

Maternal NOAEL = 30 mg/kg/day, based on decreased body weight and food
consumption at 100 mg/kg/day

Incidental Oral

Intermediate-Term

(1-6 months)

 	NOAEL = 30 mg/kg/day

 	Target MOE= 100 (10x inter-species extrapolation, 10x intra-species
variation)

	Developmental Toxicity – Rat (Copper Naphthenate)

 MRID 41615101

Maternal NOAEL = 30 mg/kg/day, based on decreased body weight and food
consumption at 100 mg/kg/day

Short -Term Dermal

(1 - 30 Days)	LOAEL=100 mg/kg/day

(22,222 µg/cm2)a	Target MOE=300 (10x inter-species extrapolation, 10x
intra-species variation, 3x for use of LOAEL)

	90-day dermal toxicity-rabbit MRID 41515001 (Zinc naphthenate)

LOAEL(dermal) = 100 mg/kg/day, based on erythema, edema, and
desquamation at 100 mg/kg/day

Intermediate -Term Dermal

(30 Days- 6 months)	NOAEL = 100 mg/kg/day	Target MOE=100 (10x
inter-species extrapolation, 10x intra-species variation)

	90-day dermal toxicity-rabbit MRID 41515001 (Zinc naphthenate)

NOAEL (systemic) = 100 mg/kg/day, based on reductions in body weight
gain observed at 300 mg/kg/day.

Inhalationb

( all exposure durations)

	NOAEL= 30 mg/kg/day

MOE = 1000	Target MOE = 1000 (10x inter-species extrapolation, 10x
intra-species variation, 10x route-extrapolation)	Developmental Toxicity
– Rat (Copper Naphthenate) MRID 41615101

NOAEL = 30 mg/kg/day, based decreased maternal body weight and food
consumption at 100 mg/kg/day.

Cancer	Not classified;  no cancer data available.

aTGAI based dermal endpoint (100 mg/kg rabbit x 2 kg rabbit x
1000µg/mg) / 9 cm2 area of rabbit dosed = 22,222 µg/cm2

b an additional uncertainty factor of 10x is used for route
extrapolation from an oral endpoint.

NOTE: The inhalation absorption factor of 100% should be used since an
oral endpoint was selected for the inhalation exposure scenarios and
there are no inhalation toxicity data available for copper or zinc
naphthenate.

		3.3.2	Dermal Absorption

		Dermal Absorption Factor

A dermal absorption factor is not necessary as there are route-specific
studies from which to assess dermal toxicity.

3.3.3	Classification of Carcinogenic Potential

There are no data from which to derive a carcinogenicity classification
of copper or zinc naphthenate.  There are summary data only for calcium
naphthenate; however, calcium naphthenate has no registrations as an
active ingredient.

3.4	Endocrine Disruption

EPA is required under the Federal Food, Drug and Cosmetic Act (FFDCA),
as amended by the Food Quality Protection Act (FQPA), to develop a
screening program to determine whether certain substances (including all
pesticide active and other ingredients) “may have an effect in humans
that is similar to an effect produced by a naturally occurring estrogen,
or other endocrine effects as the Administrator may designate.”
Following recommendations of its Endocrine Disruptor Screening and
Testing Advisory Committee (EDSTAC), EPA determined that there was a
scientific basis for including, as part of the program, the androgen and
thyroid hormone systems, in addition to the estrogen hormone system.
EPA also adopted EDSTAC’s recommendation that EPA include evaluations
of potential effects in wildlife.  For pesticides, EPA will use FIFRA
and, to the extent that effects in wildlife may help determine whether a
substance may have an effect in humans, FFDCA authority to require the
wildlife evaluations.  As the science develops and resources allow,
screening of additional hormone systems may be added to the Endocrine
Disruptor Screening Program (EDSP).

When the appropriate screening and/or testing protocols being considered
under the Agency’s EDSP have been developed, naphthenate salts may be
subject to additional screening and/or testing to better characterize
effects related to endocrine disruption.

4.0	EXPOSURE ASSESSMENT AND CHARACTERIZATION

	4.1	Summary of Registered Uses

	Residential exposures may occur as a result of post-application contact
with industrially treated items or from the use of Naphthenate Salts
products registered for residential use. Table 4.1 presents a summary of
all exposure scenarios that may occur from uses in residential sites
based on examination of product labels.  Table 4.2 identifies the
representative exposure scenarios assessed in this document.

Table 4.1. Potential Use Scenarios Based on Product Labels for
Naphthenate Salts

Use Site Category

Example Use Sites

Scenarios

Use Site Category VII

Materials Preservatives	Used to preserve and protect cellulose-based
textiles/cordage intended for exterior-use only; including non-apparel
industrial-use textiles.

	Application to rope, burlap, canvas, and similar materials in the
production of nets (not including fishing nets), seines, tents, awnings,
tarpaulins, boat and truck covers, and other outdoor-use textiles
(industrial use) and post-production applications to fabricated  textile
articles cited above (commercial and residential use).

Use Site Category X

Wood preservatives	Used in preservation of lumber and wood products for
exterior-use only, via pressure and non-pressure impregnation, and
remedial treatments to outdoor in-service standing poles.

	Application to lumber and wood processed in treatment facilities
through pressure and non-pressure treatment methods
(industrial/commercial use);

Application to fabricated outdoor-use products, such as fence posts,
patio decking, docks, boats, ladders, millworks, and greenhouse benches
(but not products that come in contact with plants grown for food)
(commercial and residential use);

Application to in-service utility poles and similar members (commercial
use only).

Table 4.2.  Representative Uses Associated with Residential Exposure

Representative Use

Exposure Scenario

Application Method

EPA Registration No.

Application Rate

Using preservative coatings/water repellents for protection of
outdoor-use wood/textiles	ST Handler:  Adult dermal and inhalation	Paint
brush or roller

Low-pressure coarse sprayer	1022-409	25% a.i. ready-to-use (RTU)
exterior treatment on landscape timber, windows, window frames, stairs,
porches, steps, fence pickets, fence rails, rope, or burlap.

Contacting treated outdoor-use textiles (e.g., treated tents, tarps,
canvas) a	ST Post-application:

Adult dermal; child incidental ingestion and dermal 	NA	43437-4	11% a.i.
(by weight) deposition in treated canvas textile.

Contacting preserved wood surface residues	ST post-app:

Adult dermal; child incidental ingestion and dermal	NA	43437-4	13% a.i.
(up to 1.5% copper by weight) used to treat wood via pressure.

Note: Surrogate DDAC Study Data Used as 3.0 μg/cm2  (hand residues)

a Exposure to textiles used outdoors treated with Naphthenate Salts is
assumed to also represent post-application exposures to rope, canvas,
burlap, and similar materials.  Non-heavy-duty textiles (such as
clothing, apparel, bedding, and home goods) are not assumed to be
treated with Naphthenate Salts.

	4.2	Dietary Exposure

	There are neither direct nor indirect food uses associated with
Copper/Zinc Naphthenate active ingredients.  There is however, one
tolerance exemption for residues of Copper Naphthenate when used in
accordance with good agricultural practices as an inert ingredient in
pesticide formulations applied to growing crops only [(40 CFR 180.920) -
No more than 2.5% Copper Naphthenate can be present, and products
containing Copper Naphthenate can only be applied before the edible
portions of plants begin to form.].

4.3	Drinking Water Exposures and Risks

There are no potable water treatment uses for registered products
containing Copper/Zinc Naphthenates, nor are effluents of this chemical
anticipated to impact fresh water environments through proper product
use.

4.4	Residential Exposure/Risk Pathway

The exposure scenarios assessed in this document for the representative
uses selected by the Agency are shown in Table 4.1.  The table also
shows the maximum application rates associated with the representative
use and the EPA Registration number for the corresponding representative
product.  For handlers, the representative uses assessed include
application as a wood preservative coating/water repellent (e.g.,
applied via brush, roller, and low-pressure coarse spray to patio
decking).  Exposures evaluated for handlers include ST dermal (leading
to dermal irritation) and inhalation route contact.  Post-application
exposures were assessed for ST dermal irritation (adults/children) and
incidental oral ingestion (children) contact with treated surfaces
including preserved wood and outdoor-use textiles (e.g., treated canvas
tents or tarps).

		4.4.1	Residential Handler Exposures

	The residential handler scenarios described in Table 4.1 were assessed
to determine ST dermal and inhalation exposures.  The inhalation dose
calculations were estimated using Equations 1 through 3 in the criteria
for conducting exposure assessments section of the ORE chapter.
Residential handlers using wood preservative coatings may have
inhalation exposures to aerosol particulates during applications using a
low-pressure sprayer.  Volatile organic compounds are assumed to be
present from carrier solvents (e.g., aliphatic hydrocarbon reducing
solvents) and formulation inert ingredients (e.g., petroleum
distillates), but they are not attributed to the Naphthenate active
ingredient and are therefore not assessed.

	The assumptions and factors used for those scenarios in which surrogate
data were used include the following:

Unit Exposure Values: Unit exposure values were taken from the Pesticide
Handlers Exposure Database (PHED) data presented in HED’s Residential
SOPs (USEPA, 1998).  A summary of the PHED database is presented in
Appendix A.

For the low pressure sprayer (coarse spray) in coating applications
scenario, the PHED dermal and inhalation unit exposure values for a
residential handler pouring a pesticide and applying it via a low
pressure sprayer (handwand) were used (PHED Scenario 32).  These unit
exposure values [102 mg/lb a.i. for dermal (hand only) and 0.030 mg/lb
a.i. for inhalation] represent a handler treating low and mid-level
targets (generally below the waist) while wearing no gloves or
respirator PPE.

For the paint brush/roller scenario, PHED dermal and inhalation unit
exposure values for a residential handler applying a pesticide using a
paint brush were used (PHED Scenario 22).  These unit exposure values
[175 mg/lb a.i. for dermal (hand only) and 0.28 mg/lb a.i. for
inhalation] represent a handler with no gloves or respirator PPE.

	As presented in Table 3.2, dermal irritation is a relevant
toxicological endpoint for ST exposures.  To estimate the potential for
dermal irritation, a dermal exposure based on skin surface area was
calculated.  This was accomplished by dividing the unit exposure values

for the hand surface (i.e., in mg/lb a.i.) from PHED by an assumed total
hand surface area (820 cm2) to obtain a normalized exposure per square
centimeter of skin (i.e., mg/lb a.i./cm2).  Using this approach, the
following dermal unit exposure values were developed:

Low pressure sprayer:  102 mg/lb a.i / 820 cm2  = 0.124 mg/lb a.i./cm2

Paint brush/roller:  175 mg/lb a.i / 820 cm2  = 0.213 mg/lb a.i./cm2

Quantity Handled/Treated:  The quantities handled/treated were estimated
based on information from various sources and assumptions.  The density
of the ready-to-use product is assumed to be 8.5 lbs/gallon based on a
review of product labels.

For the low pressure sprayer coating applications it is assumed that
42.5 lbs (approximately 5 gallons) of ready-to-use product will be used.

For the brush/roller scenario, it is assumed that 17 lbs (approximately
2 gallons) of ready-to-use products will be used.  This is based on the
90th percentile value of 8 gallons of latex paint used per year divided
by the mean frequency of 4 painting events/year.

Duration of Exposure:  The duration of exposure for most homeowner
applications of Naphthenate Salts products is believed to be best
represented by the short-term duration (1 to 30 days).  For example, the
Agency assumes that application to outdoor-use wood materials (e.g.,
fencing, patio decking) are episodic, not daily.  Therefore, exposures
are evaluated for only short-term (ST) durations.

Results

	The resulting short-term exposures and MOEs for the representative
residential handler scenarios are presented in Tables 4.3 and 4.4.  As
shown in Table 4.3, the calculated MOEs were above the target inhalation
MOE of 1,000 for both scenarios.  Table 4.4 shows that calculated dermal
irritation exposure for both application scenarios. The dermal MOEs (4
and 6) are both below the ST MOE target of 300, denoting potential
dermal irritation concern.

Table 4.3. Naphthenate Salts Residential Handlers ST Inhalation
Exposures and MOEs

Method of Application

Unit Exposure

(mg/lb a.i.)a

Application Rate

Quantity Handled/ Treated per Day

Absorbed Daily Dose (mg/kg/day)b

MOE

(Target = 1,000)c

Low Pressure Sprayer	0.030	25% a.i. by weight	42.5 lbs/day

(5 gal/day)	0.0045	6,700

Brush/roller	0.284	25% a.i. by weight	17 lbs/day

(2 gal/day)	0.017	1,800

a	No respirator used by exposed individual.

b	Inhalation Daily Dose (mg/kg/day) = [inhalation unit exposure (mg/lb
a.i.) * application rate (0.25) * quantity handled (lbs/day) *
inhalation absorption factor 100% / body weight (70 kg).

c 	Inhalation MOE = NOAEL (30 mg/kg/day) / Daily Dose.  Target
inhalation MOE is 1,000.

Table 4.4. Naphthenate Salts Residential Handlers ST Dermal Exposures
and MOEs

Method of Application

Unit Exposure

(mg/lb a.i./cm2)a

Application Rate

Quantity Handled/ Treated per day

ST Absorbed Daily Dose (mg/cm2)b

MOEc

ST Dermal Irritation

(Target = 300)

Low Pressure Sprayer

0.124

	25% a.i. by weight	42.5 lbs/day

(5 gal/day)	5.3	4

Brush/roller	0.213	25% a.i. by weight	17 lbs/day

(2 gal/day)	3.6	6

a	All dermal unit exposures represent ungloved replicates.  The low
pressure sprayer and brush/roller unit exposures represent short sleeve
and short pant replicates.

b	Dermal Daily Dose (mg/cm2) = [(PHED hand unit exposure (mg/lb
a.i.)/surface area of adult hand (820 cm2)] * application rate (0.25) *
quantity handled (lbs).

c	Dermal MOE = ST Dermal Irritation concentration (22.222 mg/cm2) /
Daily Dose.  Short-term target dermal MOE is 300.

		4.4.2	Residential Post-application Exposures tc \l3 "4.4.2	Residential
Post-application Exposures

	For the purposes of this screening-level assessment, post-application
scenarios have been developed that encompass multiple products, but
still represent high-end exposure scenarios for all products
represented.  As shown in Table 4.1, representative post-application
scenarios assessed include contacting treated textiles (adult/child
dermal and incidental oral exposure to children) and contacting treated
wood (adult/child dermal and incidental oral exposures to children).  It
should be noted that because Naphthenate Salts have a relatively low
vapor pressure, post-application inhalation exposures were not assessed.

			<IP_ADDRESS> Treated Outdoor-Use Textiles tc \l4 "<IP_ADDRESS>	Treated
Outdoor-Use Textiles

	Certain types of textiles are treated with Naphthenate Salts during
industrial manufacturing processes or as a result of registered
residential use applications. These cellulose textiles and cordage
include: canvas tents/tarps, rope, and other products.  Post-application
dermal and incidental oral exposures to treated textiles may occur as
infrequent, episodic events.  Because the textiles impregnated with
Naphthenate Salts are assumed to be used in residential setting, there
is potential for acute exposures to occur.  Therefore, only short-term
exposure durations were assessed.  It was assumed that exposure to a
canvas fabric covering (tent) will represent exposure to all other types
of textiles and similar materials treated with Naphthenate Salts
(including rope).

Dermal Exposure to Adults and Toddlers from Contacting Treated Textiles
(Canvas Tents)

	The Agency assumes that there is the potential for dermal exposure to
adults and children from contact with treated outdoor-use fabrics.  To
evaluate this possibility, the Agency evaluated a scenario in which
adults and children are directly exposed to a treated canvas tent.  This
post-application assessment assumes the tent is new (i.e., not laundered
and not yet exposed to rainfall and outdoor elements) as a conservative
measure (i.e., the effect of dislodgeable residues being diminished over
time is not quantifiable).

Exposure Calculations

	There is the potential for short-term dermal exposures leading to
irritation when adults and children contact textiles that have been
treated with Naphthenate Salts.  To determine the dermal exposure to
Naphthenate Salts for this scenario, the following equation was used:

PE = P * WF1 * WF2 * PF

where:

PE 	= 	Potential exposure (mg/cm2)

P 	= 	Fabric density (mg/cm2)

WF1 	= 	Weight fraction of commercial product in textile (mg product
a.i./mg textile)

WF2 	= 	Weight fraction of Naphthenate Salts transferred from textile to
skin (unitless)

PF	= 	Protection factor from single layer of clothing or sheet
(unitless)

Assumptions

The canvas tent cloth textile is assumed to be medium weight Army Duck
Canvas (12 oz/yd2) with a density of  408 g/m2 (40.8 mg/cm2)  [This
density estimate is based on a weight specification chart from an
internet source of exported canvas textile (Bharat Textiles, 2007)].

The product is applied at a rate of 11 % percent a.i. by weight to the
textile (based on a recommended maximum application rate of 1.2% copper
metal by weight).

No data were available from which a transfer factor could be estimated.
Potential doses were calculated using a conservative percent transfer of
100%, which assumes that all residues are transferable from textile
surfaces to the skin.  Because the calculated MOE was less than the
target MOE for ST exposure, a less conservative estimate of dermal
exposure was also calculated assuming a transfer factor of 5%.

As a conservative approach it is assumed that adults and children are
sleeping inside a treated tent with no bedding between body and tent
floor surfaces, wearing short pants/tee-shirt or just undergarments.
The protection factor inhibiting exposure to Naphthenate Salts in the
tent fabric from clothing is 50% based on PHED protection factor for a
single layer of clothing (USEPA 1998).

Results

	Table 4.5 shows the calculation of the short-term dermal exposure and
MOE for children and adults contacting treated textiles. The MOEs are
below the short-term target of 300 for both scenarios using transfer
factors. The MOEs are 10 at 100% and 200 at 5%, indicating potential
dermal irritation concerns.

Table 4.5. Short-term Dermal Exposure and MOE for Children and Adults
Contacting Treated Textiles

Weight Fraction of Product

(% a.i.)	Fabric Density (mg/cm2)	Fraction Transferred to Skin	Protective
Factor	Exposure Dose

(mg/cm2) a	MOEb

	Short Term (Target = 300)

11%	40.8	100%	50%	2.2	10

11%	40.8	5%	50%	0.11	200

a  Potential exposure for ST and IT is expressed as mg a.i. per cm2 of
exposed skin.  Equation used to estimate exposure is presented above.

b  MOE = NOAEL/exposure estimate [Where: ST and IT NOAEL = 22.222
mg/cm2].

Incidental Oral Exposure to Toddlers Mouthing Treated Textiles (Canvas
Tents/Tarps)

	Based on the dermal scenario developed above, there is the potential
for ST incidental oral exposure to toddlers from mouthing textiles
(e.g., canvas tents/tarps) treated with Naphthenate Salts.

Exposure Calculations

Potential doses are calculated as follows:

PDD = C * SE * SA

	    BW

Where:

PDD	= 	potential daily dose (mg/kg/day);

C 	= 	concentration on textile (mg/cm2);

SE	=	saliva extraction efficiency (%);

SA 	= 	surface area mouthed (cm2/day); and

BW 	= 	body weight (kg).

And

C = WFai * W * CF1 * CF2

Where:

C		=	concentration on textile (mg/cm2);

WFai		= 	weight fraction of a.i. in textile (unitless);

W 		= 	weight of textile (g/m2);

CF1		=	unit conversion factor (1,000 mg/g); and

CF2		=	unit conversion factor (0.0001 m2/cm2).

Assumptions

The canvas tent cloth textile is assumed to be medium weight Army Duck
Canvas (12 oz/yd2) with a density of  408 g/m2 (40.8 mg/cm2)  [This
density estimate is based on a weight specification chart from an
internet source of exported canvas textile (Bharat Textiles, 2007)].

The product is applied at a rate of 11% a.i. by weight to the textile
(based on a recommended maximum application rate of 1.2% copper by
weight).

The saliva extraction efficiency was 50% (USEPA, 2000 and 2001).

The surface area of textile mouthed by toddlers is 20 cm2 (professional
judgment).

Toddlers (3 years old) are used to represent the 1 to 6 year old age
group.  For three-year olds, the median body weight is 15 kg (USEPA,
1997a).

Results

    	Table 4.6 shows the calculation of the oral dose and oral MOE for
toddlers mouthing treated textiles.  The ST MOE value is 10, which is
below the ST target MOE of 100, indicating potential risk concern.

Table 4.6. ST Incidental Oral Exposures and MOEs for Toddlers Mouthing
Treated Textiles (Canvas Tent/Tarp)

Weight of Textile (g/m2)	Concentration on Textilea

(mg/cm2)	Surface Area Mouthed (cm2/day)

Saliva Extraction Efficiency 	Potential Daily Doseb (mg a.i./kg/day)	ST
Incidental Oral MOE (Target MOE = 100)c

408	4.5	20	50%	3	10

        a.	Concentration on textile (mg/cm2) = (Weight fraction a.i. in
clothing) * (weight of textile, g/m2) *

              (1,000 mg/g) * (0.0001 m2/cm2)

b.	Potential Daily Dose (mg/kg/day) = (concentration on textile, mg/cm2)
* (surface area mouthed, cm2/day) * (saliva extraction efficiency) /
(body weight, 15 kg).

c 	Oral MOE = NOAEL (mg/kg/day) / Potential Daily Dose [Where short-term
incidental oral NOAEL = 30 mg/kg/day].  Target MOE = 100.

			<IP_ADDRESS>	Treated Lumber tc \l4 "<IP_ADDRESS>	Treated Lumber

		Certain Naphthenate Salts end-use products are labeled for wood
preservative uses in pressure and non-pressure treatments of wood
products intended for residential applications.  Therefore, the Agency
evaluated potential post-application exposures to individuals exposed to
Naphthenate Salts-treated wood in residential settings (home and farm):

Dermal contact by children with Naphthenate Salts-treated wood products
for above-ground uses [e.g., residential playground equipment
(playsets), posts, decks, shingles, fencing, outdoor lumber, etc.]; and

Incidental ingestion by children due to hand-to-mouth contact with
Naphthenate Salts-treated wood products.

	Because children are more likely than adults to contact wood surfaces
using playground equipment (playsets), and because children have a
higher surface area to body weight ratio, they represent the maximum
exposed individual.  Incidental ingestion exposure for adults is
expected to be negligible and dermal contact for adults is expected to
be lower than children for crawling on wood decks.

Surrogate Data

	No chemical-specific residential post-application studies conforming to
Series 875 guidelines were available; however, data from the proprietary
study, “Measurement and Assessment of Dermal and Inhalation Exposures
to Didecyl Dimethyl Ammonium Chloride (DDAC) Used in the Protection of
Cut Lumber (Phase III)” (Bestari et al., 1999, MRID 455243-04, SIG
Task Force #73154) can be used as surrogate data to estimate
screening-level exposures for the following pathways: outdoor
residential dermal contact with Naphthenate Salts-treated wood products
used in above-ground applications (e.g., residential playsets, posts,
decks, shingles, fencing, outdoor lumber, etc.); and outdoor residential
incidental ingestion due to hand-to-mouth contact with pressure-treated
wood products.  The DDAC study measured dermal and inhalation exposures
for various worker functions/positions for individuals handling
DDAC-containing wood preservatives for non-pressure treatment
application methods and for individuals that could then come into
contact with the preserved wood.

Outdoor Residential Dermal Contact with Naphthenate Salts-Treated Wood
Products

	Potential risks resulting from adult/child residential dermal contact
with wood treated with Naphthenate Salts are assessed using the range of
worker residue data for hands available in the DDAC study.  Hand
sampling was performed using cotton gloves as dosimeters.  The data in
Table 4.7 were used to approximate the residues transferred from treated
wood to skin.  No other data are available (e.g., no surface wood wipe
data).  The data from the job descriptions presented below from the DDAC
study were chosen because of the worker contact with dry treated lumber.
 Each job function is represented by one test subject performing an
eight-hour work shift.  The range of concentrations on the hands (0.6 to
3.0 μg/cm2) of workers handling dry lumber shortly after treatment with
an antisapstain (i.e., surface spray, not pressure treatment) was
assumed to be the dermal skin irritation exposure of children playing on
pressure treated structures.  The results from Table 4.7 indicate that
the dermal MOEs range from 37,000 down to 7, 400 and are well above the
target MOE (i.e., 300) for all test subjects.  Considerable
uncertainties in the assessment (eight-hour work shift, surface spray
applications, and monitored shortly after application) require a
confirmatory surface wipe study on pressure treated wood to refine the
skin concentration/exposure for children playing on treated structures.

End Stacker - Operates an automated stacking system at the end of the
conveyor.  Lumber stacked into loads.  Monitoring was performed over an
eight-hour work shift.  Gloves were worn as indicated on page 196 of the
DDAC study.

Stickman - Places sticks between stacks of wood manually.  At some
mills, this is done automatically by end stacker operator.  Monitoring
was performed over an eight-hour work shift.  Gloves were not worn as
indicated on page 192 of the DDAC study.

Tallyman - Staples information sheet onto wood.  May come in contact
with treated lumber.  (Note: there were two reps available for
tallyman.)  Monitoring was performed over an eight-hour work shift.
Gloves were not worn as indicated on pages 193 and 207 of the DDAC
study.

Table 4.7.  Hand Residue Data for DDAC for Handling of Dry Wood to
Represent Potential Naphthenate Salts Adult/Child Dermal Exposure and
Risk

Job Description

(1 replicate each)	Total Hand Residue Data (μg/cm2)

(data page 104 of the DDAC study report)

End Stacker	1.2

Stickman	0.6

Tallyman	0.8

Tallyman 	3.0

(Maximum Value)

Average Hand Residue	1.4

Dermal Skin Irritation Exposurea (μg/cm2)	 Range 0.6 to 3.0

MOEb (Target MOE =300)	Range 37,000 to 7,400

a	Dermal Skin Irritation Exposure (μg/cm2)= range from 0.6 to 3.0
μg/cm2  (hand residues)

b	MOE  = NOAEL (μg/cm2) / dermal skin irritation exposure (μg/cm2).
Dermal short-term NOAEL

is 22,222 μg/cm2.  Target MOE = 300.

  SEQ CHAPTER \h \r 1 Outdoor Residential Hand-to-Mouth Contact with
Naphthenate Salts-treated Wood Products

	The daily hand-to-mouth dose (mg/kg/day) is estimated using the
following equation:

Oral Dose t= Handt * Hand SA * SEF *  Frequency * CF1 *  ET 								BW

Where:

	Handt 		=	DDAC highest hand residue detected (i.e.,“Tallyman”
working

				with dry wood) (μg/cm2)

	Hand SA	=	hand surface area (cm2/event),

SEF		=     	saliva extraction efficiency,

Frequency 	= 	frequency of exposure event (events/hr),

	ET		=	exposure time (hr/day),

	CF1		=	conversion factor (0.001 mg/µg), and

	BW		=		body weight (kg).

Assumptions

The highest hand residue value from the DDAC study (3.0 µg/cm2) was
used for this assessment.

The palmar surface area of 3 fingers of a toddler, 20 cm2, was used to
estimate hand-mouthing as opposed to whole hand mouthing (USEPA, 2001).

The saliva extraction factor (SEF), 50%, and was based on the assumption
of 50% removal efficiency of residues from hands by human saliva (USEPA,
2001 and 2005).

The rate of hand-to-mouth activity for outdoor playing is 7 events per
hour based on Freeman et. al (2001) at the 95th percentile.

 The exposure time (ET) is 2 hours and is consistent with the Agency’s
CCA assessment for time playing outdoors.  Although the 2 hour duration
represents “outdoor” time, it is used as a conservative estimate for
playing on decks and playsets.

The mean body weight of a child, age 3, is 15 kg.

Results

	The results of the hand-to-mouth estimates are presented in Table 4.8.
The estimated short-term MOE for the hand-to-mouth exposure is above the
target MOE of 100 (as 1,100) and therefore not of concern.

Table 4.8. Residential Post-application Short-term Incidental Oral
Exposures

to Naphthenate Salts-treated Wood Products

Hand Residue Concentration

from DDAC Study (µg/cm2)	Finger

Surface Area (cm2)	Exposure Frequency for Outdoor Playing (events/hr)
Saliva Extraction Factor	Exposure Time (hrs/day)	Average Daily Oral Dose
a (mg/kg/day)	ST Oral MOE (Target MOE = 100)b

3.0	20	7	50%	2	0.028	1,100

a	Average Daily Oral Dose (mg/kg/day) = [hand t (3 μg/cm2 ) x Hand SA
(20 cm2) x SEF (50% as 0.50 ) x Frequency (7 events/hr) x Exposure Time
(2 hrs/day) x 0.001 mg/μg] / BW (15 kg)

b	MOE  = NOAEL (mg/kg/day) / daily dose (mg/kg/day).  For incidental
oral exposures, the ST NOAEL is 30 mg/kg/day.  Target MOE = 100.

		4.4.3	Data Limitations/Uncertainties tc \l3 "4.4.3	Data
Limitations/Uncertainties

	There are several data limitations and uncertainties associated with
the residential handler and post-application exposure assessments.
These include the following:

In the absence of chemical-specific exposure data, handler surrogate
dermal and inhalation unit exposure values were taken from the Pesticide
Handlers Exposure Database (PHED)(USEPA, 1998) (See Appendix A for a
summary of this data source).

The quantities handled/treated and certain exposure factors were
estimated based on information from various sources, including HED’s
Standard Operating Procedures (SOPs) for Residential Exposure
Assessments (USEPA, 2000 and 2001) and AD’s Draft SOPs (unpublished
internal guidance) (USEPA, 2005).  In certain cases, no standard values
were available for some scenarios.  Assumptions for these scenarios were
based on AD estimates and could be further refined from input from
registrants.

The low pressure spray unit exposure data from PHED were used to assess
outdoor applications of wood preservative coatings (exterior of homes).
As the PHED low pressure spray data are representative of treating low
to mid-level range targets (shrubs/greenhouse benches) and the scenario
assessed in this document represents treatments that may also occur
above the waist, the unit exposure value may underestimate exposure to
the head and the upper body.

The methods used to estimate child and adult exposures to treated
textiles are highly conservative and based on approaches from the
Residential SOPs (USEPA 2000, and 2001) for contact with porous treated
surfaces (clothing, mattresses and carpets). Without data on actual
treated textile residues, dissipation or dermal transfer coefficients,
these scenarios have a high degree of uncertainty associated with them.
The registrants’ input will assist in refining the MOEs and confirming
the Naphthenate Salts textile use patterns.

In this assessment, incidental ingestion and dermal exposures to treated
wood were estimated using surrogate DDAC data (3 (g/cm2).  The degree of
uncertainty (under- or overestimation) associated with using the DDAC
hand residue data for dermal and oral exposure from contacting treated
lumber are unknown.  The amount of residue measured on the test
subjects’ hands is variable and may be influenced by the duration of
exposure, how often wood is contacted, and the degree of contact (i.e.,
do the hand residues from the DDAC study mimic a child’s play activity
on decks and playsets?).  In addition, from the limited data available
to the Agency, it appears that leaching from Naphthenate Salts-treated
wood depends on pH, with the highest leach rates occurring under acidic
conditions (USEPA, 2007a).

Data are not available to assess the levels of Naphthenate Salts in soil
contaminated from Naphthenate Salts-treated wood (e.g., above
ground/ground contact fabricated components of decks or playsets).
Because of this data gap, EPA was not able to estimate residential
post-application dermal and incidental oral ingestion exposure to soil
contaminated with Naphthenate Salts residues.  It is assumed that any
soil residues attributed to weathering of in-service wood (playsets)
will remain near these structures for potential child exposure (USEPA,
2007a).

5.0	AGGREGATE RISK ASSESSMENT AND CHARACTERIZATION

	In examining aggregate exposure, FFDCA section 408 (b)(2)(d)(vi)
stipulates that “when establishing, modifying, leaving in effect, or
revoking a tolerance or exemption for a pesticide chemical residue, that
EPA considers available information concerning the aggregate exposure
levels of consumers (and major identifiable subgroups of consumers) to
the pesticide chemical residue”  in food and all other
non-occupational exposures, including drinking water from ground water
or surface water and exposure through pesticide use in gardens, lawns,
or buildings (residential and other indoor uses).

	5.1	Acute and Chronic Dietary Aggregate Risk tc \l2 "5.1	Acute and
Chronic Dietary Aggregate Risk

	Characterization of acute and chronic dietary risk is not necessary for
naphthenate salts as there are no direct or indirect food uses of these
chemicals, and drinking water is not expected to be impacted from the
current uses.

	5.2	Short-Term Aggregate Risks tc \l2 "5.2	Short- and Intermediate-Term
Aggregate Risk

	In order for a pesticide registration to continue, it must be shown
“that there is reasonable certainty that no harm will result from
aggregate exposure to pesticide chemical residue, including all
anticipated dietary exposures and other exposures for which there are
reliable information.”  Aggregate exposure is the total exposure to a
single chemical (or its residues) that may occur from dietary (i.e.,
food and drinking water), residential, and other non-occupational
sources, and from all known or plausible exposure routes (oral, dermal,
and inhalation).  However, this assessment only addresses non-dietary
residential aggregate exposures and risks.

	The Office of Pesticide Programs has published guidance outlining the
necessary steps to perform aggregate exposure and risk assessments
(General Principles for Performing Aggregate Exposure and Risk
Assessments, November 28, 2001; available at
http://www.epa.gov/pesticides/trac/science/aggregate.pdf).  Steps for
deciding whether to perform aggregate exposure and risk assessments are
listed, which include: identification of toxicological endpoints for
each exposure route and duration; identification of potential exposures
for each pathway (food, water, and/or residential);  reconciliation of
durations and pathways of exposure with durations and pathways of health
effects; determination of which possible residential exposure scenarios
are likely to occur together within a given time frame; determination of
magnitude and duration of exposure for all exposure combinations;
determination of the appropriate technique (deterministic or
probabilistic) for exposure assessment; and determination of the
appropriate risk metric to estimate aggregate risk.

  SEQ CHAPTER \h \r 1 Short-Term Aggregate Exposures and Risks

	   The following lists summarize all of the potential non-dietary
sources of Naphthenate Salts exposures for adults and children in
residential settings:

Adult Naphthenate Salts exposure sources:

Applying wood preservative/water repellent coatings in residential
settings;

Applying materials preservatives to cellulose-based fibers/textiles in
residential settings;

Post-application exposures to treated outdoor-use wood;

Post-application exposures to treated outdoor-use textiles.

Child Naphthenate Salts exposure sources:

Post-application exposure to treated outdoor-use wood;

Post-application exposures to treated outdoor-use textiles.

	The use patterns of the products and probability of co-occurrence must
be considered when selecting scenarios for incorporation in the
aggregate assessment.  For example, homeowner wood preservative
applications of Naphthenate Salts are considered infrequent, occurring
only once or twice a year (Agency estimate); the same for materials
preservative treatments to certain outdoor-use cellulose-based
fibers/textiles (e.g., rope, burlap, canvas).

Therefore, though possible, the probability of co-occurrence and the
potential for exposure from these use applications on the same day is
low. Also, there is limited potential for co-occurrence from
post-application contact with pesticide residues in/on treated
wood/textile materials. This is based on the premise that children and
adults are anticipated to contact treated wood used in fabricated
residential structures (e.g., decks, fences and playsets) in far greater
frequency than the episodic contact expected with treated textiles.

Because the endpoints for the ST dermal and incidental oral routes of
exposure were based on route-specific studies resulting in different
effects, separate route-specific aggregate assessment are appropriate.
However, only one exposure scenario of concern was identified for each
route of exposure. Accordingly, evaluation of aggregate risk    as
outlined in the OPP guidance for aggregate risk assessment (September 1,
2000, Standard Operating Procedure (SOP) for Incorporating Screening
Level Estimates of Drinking Water Exposure into Aggregate Risk
Assessments) is not required.

6.0	CUMULATIVE EXPOSURE AND RISK

	The Food Quality Protection Act [FQPA] requires that the Agency
consider “available information” concerning the cumulative effects
of a particular pesticide’s residues and “other substances that have
a common mechanism of toxicity”. The reason for consideration of other
substances is due to the possibility that low-level exposures to
multiple chemical substances that cause a common toxic effect by a
common toxic mechanism could lead to the same adverse health effect as
would a higher level of exposure to any of the substances individually.
Unlike other pesticides for which EPA has followed a cumulative risk
approach based on a common mechanism of toxicity, EPA has not made a
common mechanism of toxicity finding for Naphthenate salts. For
information regarding EPA’s efforts to determine which chemicals have
a common mechanism of toxicity and to evaluate the cumulative effects of
such chemicals, see the policy statements released by EPA’s Office of
Pesticide Programs concerning common mechanism determinations and
procedures for cumulating effects from substances found to have a common
mechanism on EPA’s website -http://www.epa.gov/pesticides/cumulative/

7.0	OCCUPATIONAL EXPOSURE ASSESSMENT

	7.1	Summary of Registered Uses

	Potential occupational handler exposure can occur in various use sites,
including both commercial/industrial premises and applications conducted
at residential sites.  The exposure scenarios assessed in this document
for the representative uses selected by AD are presented in Table 7.1.
The table also shows the maximum application rates associated with the
representative use and the appropriate EPA Registration number for the
product label.  For handlers, the representative uses assessed include
use of products containing Naphthenate Salts as a preservative for
outdoor-use textiles and wood products. Due to the complexity of the
analysis of exposures that occur in wood treatment facilities, the
results for handlers and post-application exposures are presented
separately in the wood preservation section.

It should be noted that for the dermal route, only intermediate-term
(IT) dermal exposure is assessed for occupational handler scenarios
since the IT toxicity endpoint selected is based on systemic effects.
Short-term (ST) dermal exposures were not evaluated because the ST
toxicity endpoint is based on dermal irritation. Dermal irritation
exposures and risks will be mitigated using label-specified personal
protective equipment (PPE) or default PPE requirements based on the
toxicity of the end-use product. To minimize dermal exposures, the
minimum PPE required for mixers, loaders, and others exposed to end-use
products that result in classification of category I, II, or III for
skin irritation potential will be a long-sleeve shirt, long pants,
shoes, socks, chemical-resistant gloves, and a chemical-resistant apron.
Once diluted, if the concentration in the diluted solution will result
in classification of toxicity category IV for skin irritation potential,
then the chemical-resistant gloves and chemical-resistant apron can be
eliminated for applicators and others exposed to the dilute product.
Note that chemical-resistant eyewear will be required if the end-use
product is classified as category I or II for eye irritation potential.

Table 7.1.  Representative Exposure Scenarios Associated with
Occupational Exposures to Naphthenate Salts

Representative Use	Method of Application	Exposure Scenario
Representative EPA Reg. No.	Maximum Application Rate

Material Preservatives

Direct application to outdoor-use textiles (e.g., canvas used for tarps
and tents;  ropes, nets)	(Dipping) a

Low-pressure spray

Brush/roller

	Handler:

IT dermal; ST/IT/LT inhalation	1022-409

(spray)

	25% a.i. by weight,

ready-to-use (RTU)

	60061-16; 60061-19

(brush)	22% a.i. by weight,

ready-to-use (RTU)

Incorporation into textiles during  industrial manufacturing	Liquid pour
(associated with automated dip/spray) b

Liquid pump (associated with automated dip/spray) b

43437-3;

43437-4

	11% (by weight) deposition in treated canvas textile.  Incorporation
during manufacturing.

Wood Preservatives

Non-pressure treatment of wood and wood products in wood treatment
facilities	Handler Worker Functions

Diptank Operators

Blender/spray operators

Chemical operators

Post-Application Worker Functions

Graders

Trim saw operators

Clean-up crews

Construction workers 	Handler:

IT dermal; ST/IT/LT inhalation

Post-application:

IT dermal; ST/IT/LT  inhalation

	1022-409;

1022-522;

9630-31.	Blender/spray operators:

25% a.i. in solution used

(RTU product 1022-409); and for wood composite use a 1.4% a.i. solution
(1022-522)

[i.e., 3% (0.03) w/w * 45.4% a.i. in product = 1.4 % a.i.].

Diptank operators:

25% a.i. RTU (1022-409) and

32% a.i. use-solution (9630-31) [i.e., 1:2 v/v use dilution * 63% a.i.
in product = 31.5 (32 % a.i.].

All other worker functions:

25% a.i. in product

(RTU product 1022-409)

Pressure treatment of wood and wood products in wood treatment
facilities	Handler Worker Functions

Treatment assistant

Treatment operator

Post-Application Worker Functions

Tram setter, stacker operator, loader operator, supervisor, test borer,
and tallyman	Handler:

IT dermal; ST/IT/LT inhalation

Post-application:

IT dermal; ST/IT/LT  inhalation

	43437-4	13% a.i. by weight in treatment solution (89% a.i. in product
diluted with 7 parts solution by volume) c

General preservation of wood/lumber in commercial sites (non-pressure
treatment applications) d,e	Brush/roller

Airless sprayer d

Low-pressure sprayer	Handler:

IT dermal; ST/IT/LT inhalation

	7424-1;

1022-409	25% a.i. in solution used

(RTU products)

Application to in-service utility poles, pilings, posts, and other
standing timbers	Brush, trowel, or caulking/grease gun f

Pre-manufactured  bandage f	Handler:

IT dermal; ST/IT/LT inhalation

	75341-5

(Highest Use Rate for exterior surface treatments)	20% a.i. by weight in
applied product (RTU).

a	Handler exposures during dipping/immersion operations for textiles are
assumed to be comparable to diptank operations for wood.  Therefore this
scenario is not directly assessed. Refer to the non-pressure treatment
(diptank operator) scenario as representative.

b	Exposures to handlers during preparation of dipping solution were
assessed assuming a liquid pour (open-loading) or operation of a liquid
pump (closed-delivery) associated with automated (large-scale) dipping
of textiles in an industrial setting.  However, based on the label use
instructions, it is possible that manual dipping may also be used for
preservation of textiles (e.g., via preparation of small-scale dipping
solution by pouring product into a small receptacle and manually dipping
textiles).  Exposures that may occur as part of manual dipping activity
are not assessed here.

c	Application rate calculations where concentrated product is diluted
assume that the densities of product and solution are approximately
equivalent; actual densities of product and solution may vary somewhat.

d	The label indicates that applications to existing homes can be made
through brush or spray.  The airless sprayer method was selected because
it is based on applying preservative to the outside of a house in the
same manner as one would use an airless paint sprayer, not an
aerosolized paint sprayer.  It was also assumed that a low-pressure
sprayer could be used for applications involving smaller amounts of
product or area treated.

e	Immersion of wood/lumber is another use application that may occur at
commercial sites outside of wood treatment facilities; however,
exposures for this scenario are assumed to be subsumed by the
non-pressure treatment (diptank operator) scenario.

f	No data were identified on exposures to handlers applying products to
exterior surfaces of in-service poles using a trowel, or to interior
surfaces using a caulking gun or mechanical pump injection, (nor data on
other 	remedial-treatment products such as pre-manufactured
bandages/wraps); exposures were assessed using unit exposure data for a
brush use scenario as representative of all remedial use patterns.  The
product 	selected for this assessment (EPA Reg. No. 75341-5) has the
highest use rate for exterior surface treatments where commercial
applications can be made by brush (20% ai).  A remedial product for use
only in filling 	interior cavities (pre-drilled holes) of poles has a
higher application rate of 28% ai  (EPA Reg. No. 75341-2) but unit
exposure data are unavailable to assess this application method
(caulking gun) so the 20% a.i. product is used.

7.2	Occupational Handler Exposures

	 Certain occupational handler scenarios included in Table 7.1 were
assessed to determine dermal and inhalation exposures.  The general
assumptions and equations that were used to calculate occupational
handler risks are provided in Section 1.2, Criteria for Conducting the
Risk Assessment.  The scenarios were assessed using either CMA or PHED
data and Equations 1 through 3.

Unit Exposure Values (UE):  Dermal and inhalation unit exposure values
were taken from the proprietary Chemical Manufacturers Association (CMA)
antimicrobial exposure study (USEPA, 1999: DP Barcode D247642) or from
the Pesticide Handlers Exposure Database (PHED; USEPA, 1998).

For the low pressure spray scenarios (application to outdoor-use
textiles and general preservation of wood), the occupational PHED
inhalation unit exposure values for a handler pouring a pesticide and
applying it via a low pressure sprayer (handwand) was used (PHED
Scenario 32).  The unit exposure values of 100 mg/lb a.i. for ungloved
dermal, 0.43 mg/lb a.i. for gloved replicates, and 0.030 mg/lb a.i. for
inhalation represent a handler treating low and mid-level targets,
generally below the waist (greenhouse benches and shrubs) while wearing
a single layer of clothing.

For roller/brush scenarios (application to outdoor-use textiles and
general preservation of wood and application to in-service wood), the
occupational PHED inhalation unit exposure value for paintbrush
applications (PHED Scenario 22) was used (single layer of clothing, no
respirator). The dermal unit exposures are 180 mg/lb a.i. for ungloved
replicates and 24 mg/lb a.i. for gloved replicates.  The inhalation
exposure value is 0.28 mg/lb a.i.:

No data were identified on exposures to handlers applying product to
in-service poles and similar members using a trowel, caulking gun, or
pre-manufactured bandage.  Exposures for these scenarios were also
assessed using unit exposure data for the brush/roller use scenario.

For the liquid pour scenario (associated with open-loading in
preparation of automated application via dip/spray mechanism for
preservation of textiles and similar materials), the CMA dermal unit
exposure value of 0.135 mg/lb a.i. and inhalation unit exposure value of
0.00346 mg/lb a.i. for liquid pour (gloved data) of preservative was
used.  The value is based on two replicates where the test subjects were
wearing a single layer of clothing and chemical resistant gloves.  Since
no baseline dermal (unlgoved) unit exposure data are available for
preservative uses in textiles, the baseline dermal exposures were
evaluated using the cooling tower CMA data (50.3 mg/lb ai).

For the liquid pump scenario (associated with closed-delivery in
preparation of automated application via dip/spray mechanism for
preservation of textiles and similar materials), the CMA dermal unit
exposure value of 0.00629 mg/lb a.i. and inhalation unit exposure value
of 0.000403 mg/lb a.i. for liquid pump (gloved data) of preservative was
used.  The value is based on two replicates where the test subjects were
wearing a single layer of clothing and chemical resistant gloves. Since
no baseline dermal (unlgoved) unit exposure data are available for
preservative uses in textiles, the baseline dermal exposures were
evaluated using the cooling tower CMA data (0.454 mg/lb ai).

For the airless spray scenario, the occupational PHED inhalation unit
exposure value for airless sprayer application (PHED scenario 23) was
used (single layer of clothing). The dermal unit exposures are 38 mg/lb
a.i. for ungloved replicates and 14 mg/lb a.i. for gloved replicates.
The inhalation exposure value is 0.83 mg/lb a.i.

Quantity handled/treated: The quantity handled/treated values were based
primarily on AD assumptions.  The following assumptions were made:

For the scenarios involving low pressure spray, the quantity handled
depends on the material that is being treated.  The following values
were used for the different materials based on AD assumptions:

Textiles:  85 lbs (10 gal of ready-to-use product with a density of
8.5 lb/gal)

Application of general wood preservative or coating:  425 lbs of fluid
(50 gallons of ready-to-use product with a density of 8.5 lb/gal)

For the roller/brush application scenarios, it was assumed that 42.5 lbs
of treatment fluid (approximately 5 gallons with a density of 8.5
lb/gal) are used based on AD assumptions.

For the liquid pour scenario, it was assumed that 10,000 lbs of textiles
are treated per day in open-loading systems based on AD assumptions
(USEPA, 2005).

For the liquid pump scenario, it was assumed that 10,000 lbs of textiles
are treated per day in closed-delivery systems based on AD assumptions
(USEPA, 2005).

For the airless spray scenario, it was assumed that 425 lbs of
ready-to-use treatment fluid (approximately 50 gallons of with a density
of 8.5 lb/gal) are used based on AD assumptions.

Duration of Exposure:  It is assumed that occupational handlers will
have exposures of ST, IT, and LT durations in industrial/commercial
settings.  Based on assigned toxicity endpoints, the MOEs were
calculated for ST, IT, and LT inhalation and IT dermal exposures. Refer
to endpoint selection in Table 3.2.

Exposure Calculations and Results

	The resulting dermal and inhalation exposures and MOEs for the
representative occupational handler scenarios are presented in Tables
7.2a and 7.2b.  Calculated MOEs were below the target MOEs of 100 for IT
dermal and 1,000 for ST/IT/LT inhalation for the following scenarios
listed.  It should be noted that for MOEs below 1,000, the Agency may
request a confirmatory inhalation toxicity study to refine the potential
risks since the current inhalation endpoint is based on an oral NOAEL.

Dermal:

Preservation of textiles, low-pressure sprayer:  MOE = 3 at baseline
dermal;

Preservation of textiles, brush/roller:  MOE = 4 at baseline and 33 with
glove PPE;

Preservation of textiles, liquid pour:  MOE = < 1 at baseline and 50
with glove PPE;

Preservation of textiles, liquid pump: MOE = 14 at baseline;

General preservation of wood, brush/roller: MOE = 4 at baseline, 25 with
glove PPE;

General preservation of wood, airless sprayer: MOE = 2 at baseline, 5
for glove PPE;

General preservation of wood, low-pressure sprayer:  MOE = 3 at
baseline;

Application to in-service utility poles, brush: MOE = 5 at baseline, 33
for glove PPE.

Inhalation:

Preservation of textiles, brush/roller:  MOE = 750 without respirator
PPE;

Preservation of textiles, liquid pour:   MOE = 600 without respirator
PPE;

General preservation of wood, brush/roller:  MOE = 700 without
respirator PPE;

General preservation of wood, airless sprayer: MOE = 23 without
respirator PPE and 230 with respirator use;

Application to in-service utility poles, brush: MOE = 880 without
respirator PPE.

Table 7.2a  Intermediate-Term Dermal Risks Associated with Occupational
Handlers

Exposure Scenario

Method of Application	Dermal Unit Exposure

 (mg/lb a.i.)

	Application Rate (% a.i. by weight)	Quantity Handled/ Treated per day
Dermal

Absorbed Daily Dose (mg/kg/day)c	IT Dermal

 MOEd

(Target MOE = 100)

Baseline Dermala	PPE-Gloves Dermalb

	Baseline Dermal	Glove PPE	Baseline Dermal	Glove PPE

Material Preservatives

Preservation of  outdoor-use textiles	Low-pressure sprayer	100	0.43	25%
85 lbs	30	0.13	3	770

	Brush/roller	180	24	22%	42.5 lbs	24	3	4	33

	Liquid pour	50.3	0.135	11%	10,000 lbs	790	2	0.13	50

	Liquid pump	0.454

0.00629	11%	10,000 lbs	7	0.11	14	910

Wood Preservatives

General preservation of wood	Brush/roller	180	24	25%	42.5 lbs	27	4	4	25

	Airless sprayer

38

14	25%	425 lbs	58	21	2	5

	Low-pressure sprayer	100	0.43	25%	85 lbs	30	0.13	3	770

Application to

 in-service utility poles	Brush	180	24	20%	42.5 lbs	22	3	5	33

* Note:  Other occupational scenarios for wood preservatives are
assessed separately in Section 6.4.  IT = intermediate-term.

	a	Baseline Dermal:  Long-sleeve shirt, long pants, no gloves. It should
be noted that the baseline dermal unit exposures for the preservation of
textiles were from the cooling tower CMA data set because baseline
(ungloved) dermal unit exposures are not available for the CMA data set
on preservatives.

	b	PPE Dermal with gloves: baseline dermal plus chemical-resistant
gloves.

c	Absorbed Daily dose (mg/kg/day) = [unit exposure (mg/lb a.i.) *
absorption factor (NA for dermal) * application rate * quantity treated
/ Body weight (70 kg).

d	MOE = NOAEL  (mg/kg/day) / Absorbed Daily Dose [Where IT dermal NOAEL
= 100 mg/kg/day].

Table 7.2b  Short-, Intermediate-, and Long-Term Inhalation Risks
Associated with Occupational Handlers

Exposure Scenario

Method of Application	Inhalation Unit Exposure (mg/lb a.i.)	Application
Rate (% a.i. by weight)	Quantity Handled/ Treated per day	Inhalation
Absorbed Daily Dose (mg/kg/day)a	Inhalation

ST/IT/LT MOEa

(Target MOE = 1,000) **

Material Preservatives

Preservation of  outdoor-use textiles	Low-pressure sprayer	0.03	25%	85
lbs	0.009	3,300

	Brush/roller	0.28	22%	42.5 lbs	0.04	750	7,500

(PPE)

	Liquid pour	0.00346	11%	10,000 lbs	0.05	600	6,000

(PPE)

	Liquid pump	0.000403	11%	10,000 lbs	0.0063	4,800

Wood Preservatives

General preservation of wood	Brush/roller	0.28	25%	42.5 lbs	0.043	700
7,000

(PPE)

	Airless sprayer	0.83	25%	425 lbs	1.3	23	230

(PPE)

	Low-pressure sprayer	0.03	25%	85 lbs	0.009	3,300

Application to in-service utility poles	Brush/roller	0.28	20%	42.5 lbs
0.034	880	8,800

(PPE)

* Note:  Other occupational scenarios for wood preservatives are
assessed separately in Section 6.4 of the ORE chapter.

	ST= Short-term;  IT = intermediate-term; and LT = long-term.

Unit Exposure (UE) Data are from CMA for Liquid pour/Liquid pump
scenarios, and PHED for Brush and Low pressure/Airless sprayer

	applications.

	** CMA and PHED Surrogate Inhalation Unit Exposure Data are baseline
values representing no respirator use as PPE.  For scenarios 	assessed
with PHED data, a protection factor of 90% can be applied to UE values
to represent use of organic vapor respirators for any 	inhalation
scenarios with MOEs below the target of 1000 (i.e.,Brush/Roller and
Airless Sprayer).  Protection factors are not applied to 	CMA Datasets.

a	Absorbed Daily dose (mg/kg/day) = [unit exposure (mg/lb a.i.) *
absorption factor (100% (1.0) for  inhalation) * application rate *
quantity treated / Body weight (70 kg).

b	MOE = NOAEL  (mg/kg/day) / Absorbed Daily Dose [Where ST/IT/LT
Inhalation NOAEL = 30 mg/kg/day].

7.3	Occupational Post-application Exposures

                Except for the post-application scenarios assessed for
wood preservatives in Section 6.4, occupational post-application
exposures are assumed to be negligible.

	7.4 	Wood Preservation

 tc \l2 "6.4	Wood Preservation

	Copper and Zinc Naphthenates are used industrially as a wood
preservative in treating wood for exterior uses (above-ground,
ground-contact, below-ground, and fresh or salt water).  Copper
Naphthenate imparts a dark-green color to wood which weathers over time
to a light brown.  In contrast, Zinc Naphthenate does not impart color
to treated wood, making it easier to apply paint finishes.  Both
chemicals may leave wood with a noticeable odor, which takes time to
dissipate for Copper Naphthenate, but may linger for Zinc
Naphthenate-treated wood.

	The formulated EP preservatives are usually supplied as solvent, water
or oil-based solutions having a guaranteed metal content. Copper
Naphthenate is also used as a remedial surface treatment for fabricated
end-cuts of pressure treated wood and as remedial treatment to
in-service standing wood utility poles, mine timbers, bridge timbers,
and cross-ties and stakes. Registered uses for Naphthenate Salts include
wood preservative treatments as wood surface coatings [e.g., wood
protection treatment (including as water repellents) applied via brush,
roller, or spray] and impregnation into wood via non-pressure (e.g.,
non-pressure dipping/immersion) and pressure techniques
(vacuum/full-cell).  The products can be used on different types of
wood, including 1) dry, well-seasoned debarked lumber, poles, posts, and
timbers; 2) manufactured wood products such as plywood and particle
board (wood composites); 3) to a minor degree for green, un-seasoned
lumber/timbers; and 4) finished wood products such as millwork,
shingles, shakes, siding, plywood and structural lumber.

	The exposure scenarios assessed in this document for the representative
wood preservation uses selected by AD are shown in Table 7.1. The
exposure analysis for scenarios involving general preservation of wood
and application to in-service utility poles and similar items is
presented in section 7.2. In Section 7.4.1, the exposure analysis for
the handler and post-application scenarios for non-pressure treatment
scenarios is presented. The exposure analysis for the handler and
post-application scenarios for pressure treatment scenarios is presented
in Section 7.4.2.

		7.4.1 	Non-Pressure Treatment Scenarios (Handler and Post-application)

	Handler and post-application scenarios for non-pressure treatment of
wood were identified and assessed using surrogate data. The proprietary
study, “Measurement and Assessment of Dermal and Inhalation Exposures
to Didecyl Dimethyl Ammonium Chloride (DDAC) Used in the Protection of
Cut Lumber (Phase III)” (Bestari et al., 1999, MRID 455243-04)
identified various worker functions/positions for individuals that
handle DDAC-containing wood preservatives for non-pressure treatment
application methods and for individuals that could then come into
contact with the preserved wood. Representative worker
functions/positions identified in the DDAC study are presented below. It
was assumed that the workers at facilities using Naphthenate Salts as a
preservative and handling the treated wood are performing similar tasks
as those monitored in the DDAC study. This study was sponsored by an
industry consortium [Sapstain Industry Group (SIG) Task Force # 73154];
therefore, data compensation issues apply for use of these data as a
surrogate source in assessing exposure.

Handler:

Blender/spray operators are workers that add the wood preservative into
a blender/sprayer system for composite wood via closed-liquid pumping.

Chemical operators for a spray box system consist of chemical operators,
chemical assistants, chemical supervisors, and chemical captains.  These
individuals maintain a chemical supply balance and are assigned the task
of flushing and cleaning spray nozzles.

Diptank Operators can be in reference to wood being lowered into the
treating solution through an automated process (i.e., elevator diptank,
forklift diptank).  This scenario can also occur in a small scale
treatment facility in which the worker can manually dip the wood into
the treatment solution.

Post-application:

Graders are expected to be positioned right after the spray box
sequence, where they grade the dry lumber by hand (i.e. detect faults).
In the DDAC study, graders graded wet lumber; therefore, the exposures
to graders using Naphthenate Salts are assumed to be the worst-case
scenarios.

Trim saw operators operate the hula trim saw and consist of operators
and strappers.  In the DDAC study, hula trim saw operators handled dry
lumber.

Millwrights repair all conveyer chains and are involved in a general
up-keep of the mill.

Clean-up crews perform general cleaning duties at the mill.

Construction workers install treated plywood, oriented strand board,
medium density fiberboard, and others.

	In lieu of chemical-specific data available regarding typical exposures
to Naphthenate Salts as a wood preservative, surrogate data were used to
estimate exposure risks. The blender/spray operator position was
assessed using CMA unit exposure data and the remaining handler and
post-application positions were assessed using data from the DDAC study
(Bestari et al., 1999).

Blender/Spray Operators

	Exposures and risks to the blender/spray operators were assessed using
Equations 1 through 3 in the criteria for conduction exposure
assessments section of the ORE chapter.  The surrogate unit exposures
were taken from the CMA study (USEPA, 1999).  Specifically, the liquid
pump preservative unit exposure for gloved workers was used in this
assessment. (Note that IT dermal exposure was assessed here since a
systemic endpoint is used. The potential for dermal irritation that
might result from ST dermal exposure is assumed to be mitigated through
the use of PPE, including chemical-resistant gloves).  The dermal unit
exposure value used was 0.00629 mg/lb a.i. and the inhalation unit
exposure was 0.000403 mg/lb a.i. These values are based on two
replicates where the test subjects were wearing a single layer of
clothing and chemical resistant gloves.  The quantity of the wood being
treated was derived from other wood preservative estimates (USEPA, 2004)
for the amount of wood slurry treated because no chemical specific data
were available for Naphthenate Salts.  It was assumed that batches of
wood   SEQ CHAPTER \h \r 1 slurry are treated in 10,000 gallon tanks,
and that eight batches of wood slurry are treated per day (one per hour
for an 8-hr work shift). Additionally, it was assumed that each batch
requires 3,000 gallons of preservatives and the remaining volume of the
tank consists of wood slurry (7,000 gallons of wood slurry per batch).
Because wood chips have a density of approximately 380 kg/m3 (SIMetric,
2007), the total amount of wood slurry treated per day is about 177,000
lbs (i.e., 8 batches/day * 7,000 gallons/batch * 0.003785 m3/gallon *
380 kg/m3 * 2.2 lb/kg).   SEQ CHAPTER \h \r 1 The assumptions used for
batch sizes and the quantity of preservative needed are consistent with
an assessment performed previously by the EPA. This assessment was
conducted using two product use-rates to denote: 1) an actual wood
composite labeled use pattern, and 2) a representative product for the
mixer/loader task involved with commercial non-pressure treatments as a
whole. A Copper Naphthenate product cites a use-application for wood
composite incorporation at a maximum level of 1.4% a.i. during
manufacture of particle board/wood fiber board (i.e., composite wood).
The product labeling for EPA Reg. No. 1022-522 (45.4% a.i.) cites
maximum incorporation of 3% w/w product based on dry weight of wood
mixed with furnish resin/binding agent (45.4% a.i. * 0.03 = 1.4 % a.i.).
 The other representative product used for non-pressure treatment is a
solvent-based ready-to-use (RTU) solution at 25% a.i. as EPA Reg. No.
1022-409.  Both product labels cite use of eye protection (goggles/face
shield) and rubber gloves as PPE.  Only the 25% a.i. RTU product
includes a respirator-use PPE statement as follows: “Wear a
NIOSH/MHSA-approved mist/vapor respirator when spraying for continued or
prolonged use of this product or for frequent use of the product.”

Table 7.3 provides the short-, intermediate-, and long-term doses and
MOEs for the blender/spray operators adding the preservative to the wood
slurry. The MOEs for the wood composite use scenario are above the
Agency targets of 100 for IT dermal (as 450) and 1000 for ST/IT/LT
inhalation (as 2,100), denoting no exposure risks of concern.  However,
for the generic non-pressure treatment mixer/loader scenario, both
dermal and inhalation MOEs pose exposure risk concerns. The dermal IT
MOE was below the target of 100 (as 25) and the inhalation ST/IT/LT MOE
was below the target of 1000 (as 120). Therefore, registrant input is
needed to clarify use rate and quantity treated. Also, a confirmatory
inhalation toxicity study may be warranted based on the results of this
assessment.

Table 7.3. Short-, Intermediate-, and Long-term Exposures and MOEs for
Wood Preservative Blender/Spray Operators

Exposure Scenario

	Dermal Unit Exposurea

(mg/lb ai)	Inhalation Unit Exposureb

(mg/lb ai)	Application Ratec

(% ai by weight)	Wood Slurry Treatedd

(lb/day)	Absorbed Daily Dosee

(mg/kg/day)	MOEsf

	Dermal	Inhalation	Dermal

IT

Target=100	Inhalation

ST/IT/LT

Target = 1000

Occupational Handler

CMA Liquid Pump	0.00629	0.000403	1.4

(wood composites)	177,000	0.22	0.0143	450	2,100

	25

(non-pressure

mix/load)

4	0.255	25	120

ST =	Short-term duration; IT =Intermediate-term duration; and LT =
long-term.

Dermal unit exposure: Single layer clothing with chemical resistant
gloves.

Inhalation unit exposure: Baseline, with no respirator.

c.	The maximum application rate is 1.4% a.i. solution for particle board
composite based on product labeling (1022-522); and maximum application
rate is 25% a.i. RTU for representative non-pressure treatment
mixing/loading (1022-409).

d.	Wood slurry treated = (8 batches/day * 7,000 gallons/batch * 0.003785
m3/gallon * 380 kg/m3 * 2.2 lb/kg)

e.	Absorbed Daily Dose = unit exposure (mg/lb ai) x App Rate (1.4% or
25% a.i. by weight as 0.014 or 0.25) x Quantity treated (lb/day) x
absorption factor (NA for dermal and 100% for inhalation) / BW (70 kg)

f.	MOE = NOAEL (mg/kg/day) / Daily dose [Where IT NOAEL = 100 mg/kg/day
for dermal and

	ST/ /IT/LT NOAEL = 30 mg/kg/day for inhalation].  Target MOE is 100 for
dermal exposure and 1000 for inhalation 	exposure.

Chemical Operators, Graders, Millwrights, Clean-up Crews, and Trim Saw
Operators

	Exposures to chemical operators, graders, millwrights, trim saw
operators, and clean-up crews were assessed using surrogate data from
the DDAC study (Bestari et al., 1999). This study examined
individuals’exposure to DDAC while working with anti-sapstains and
performing routine tasks at 11 sawmills/planar mills in Canada.  Dermal
and inhalation exposure monitoring data were gathered for each job
function of interest using dosimeters and personal sampling tubes.
These sample media were then analyzed for DDAC, and the results were
reported in terms of mg DDAC exposure per person per day.  The study
reported average daily exposures for workers in various categories.
Exposure data for individuals performing the same job functions were
averaged together to determine job specific averages.  Total exposures
from 2 trim saw workers, 13 grader workers, 11 chemical operators, 3
millwrights, and 6 clean-up staff were used.

	The individual dermal and inhalation exposures from the DDAC study are
presented in Table C-1 in Appendix C.  The representative maximum
use-application rate is 25% a.i. as a RTU product (EPA Reg. No.
1022-409) for non-pressure treatments via brush/roller/dip/spray. To
determine exposures to Naphthenate Salts, the average DDAC exposures
measured on individuals (in terms of total mg DDAC) were multiplied by a
modification factor of 0.3125 to account for the difference in percent
active ingredient between Naphthenate Salts and DDAC (25% Naphthenate
Salts in the wood preservative product versus 80% DDAC in the
comparative wood preservative product). The pounds of active ingredient
handled by each person or percent active ingredient in the treatment
solution were not provided for these worker functions.

The following equation was used to calculate daily dose for Naphthenate
Salts:

Daily Dose = DDAC UE * CR * AB

           	         BW

Where

DDAC UE	=	DDAC dermal or inhalation unit exposure (mg/day);

CR		=	Conversion ratio (25% Naphthenate Salts / 80% DDAC);

	AB		=	Absorption factor (NA for dermal, 100% for inhalation); and

BW		=	Body weight (70 kg).

In using this methodology, the following assumptions were made:

DDAC and Naphthenate Salts end products will be used in similar
quantities.

The procedures for applying both chemicals are similar.

The physical-chemical properties that affect the transport of the
chemical are similar. (This assumes similar product densities for the
DDAC and Naphthenate Salts water-borne solutions).

The limits of detections (LOD) for inhalation residues from   SEQ
CHAPTER \h \r 1 chemical operators, graders, mill wrights, and clean-up
staff replicates were not provided in the DDAC report. For lack of
better data, it was assumed that the inhalation LODs for these worker
positions are equal to the LOD of the diptank operator replicates (5.6
(g). For all measurements below the air concentration associated with
this detection limit, half the detection limit was used.  The dermal LOD
for all operators is also 5.6 (g.

In the DDAC study, dermal exposures to hands were measured separately
from the rest of the body.  For each replicate, the body dose
measurements and hand dose measurements were summed for a total dermal
dose.

Air concentrations were reported in the DDAC study. To convert air
concentrations ((g/m3) into terms of inhalation unit exposure (mg/day),
the air concentrations were multiplied by an inhalation rate of 1.0
m3/hr for light activity (EPA 1997), sample duration of 8 hrs/day, and a
conversion factor of 1 mg/1000 (g.  Table C-1 in Appendix C presents the
inhalation and dermal DDAC exposures.

Average DDAC dermal and inhalation exposures were multiplied by a
conversion ratio 0.3125 to account for the differences in Naphthenate
Salts and DDAC concentrations [i.e., (25% Naphthenate Salts / 80%
DDAC)].

Table 7.4 provides the short-, intermediate-, and long-term doses and
MOEs for chemical operators, graders, millwrights, clean-up crews, and
trim saw operators. For all worker functions the calculated dermal and
inhalation MOEs were not of concern. The inhalation MOEs are above the
target MOE of 1,000 and therefore a confirmatory inhalation toxicity
study is not warranted based on the results of this assessment. Also,
the dermal MOEs are above the target MOE of 100 for IT durations
assessed.

Table 7.4. Short-, Intermediate- and Long-Term Exposures and MOEs for
Wood Preservative Chemical Operators, Graders, Millwrights, Trim Saw
Operators, and Clean-Up Crews

Exposure Scenarioa

(number of volunteers)	Dermal UEb

(mg/day)	Inhalation UEb

(mg/day)	Conversion Ratioc 	Absorbed Daily Dosesd

(mg/kg/day)

	MOEse

Dermal	Inhalation	Dermal

IT

Target = 100	Inhalation

ST/IT/LT

Target = 1000

Occupational Handler

Chemical Operator (n=11)	9.81	0.0281	0.3125	0.044	0.00013	2,300	240,000

Occupational Post-application

Grader (n=13)	3.13	0.0295	0.3125	0.014	0.00013	7,100	230,000

Trim Saw (n=2)	1.38	0.061	0.3125	0.0062	0.00027	16,000	110,000

Millwright (n=3)	12.81	0.057	0.3125	0.057	0.00025	1,800	120,000

Clean-Up (n=6)	55.3	0.60	0.3125	0.25	0.0027	400	11,000

ST = 	Short-term duration; IT = Intermediate-term duration; and LT =
long-term

a.	The exposure scenario represents a worker wearing either long-sleeved
or short-sleeved shirts, cotton work trousers, and cotton glove
dosimeter gloves under chemical resistant gloves. Volunteers were
grouped according to tasks they conducted at the mill.

b.	Dermal and inhalation unit exposures are from Bestari et al (1999).
Refer to Table B-1 in Appendix B for the calculation of the dermal and
inhalation exposures. Inhalation exposure (mg/day) was calculated using
the following equation: air concentration ((g/m3) x inhalation rate (1.0
m3/hr) x sample duration (8 hr/day) x unit conversion (1 mg/1000 (g).
The inhalation rate is from USEPA, 1997.

c.	Conversion Ratio = 25% Naphthenate Salts / 80% DDAC (based on EPA
Reg. No. 1022-409 for 25% a.i. RTU product).

d.	Absorbed Daily dose (mg/kg/day) = exposure (mg/day) * conversion
ratio (0.3125) * absorption factor (NA for dermal and 100% for
inhalation)/body weight (70 kg).

e.			MOE = NOAEL (mg/kg/day) / Daily dose [Where IT NOAEL = 100
mg/kg/day for dermal and ST/IT/LT NOAEL = 30 mg/kg/day for inhalation ].
Target MOE is 100 for dermal and 1000 for inhalation exposure.

Diptank Operators

	Exposures to diptank operators were also assessed using surrogate data
from the DDAC study (Bestari et al., 1999). The diptank scenario
assessment was conducted differently than for the other job functions
because the concentration of DDAC in the diptank solution was provided.
Registered product use rates for dip treatments (dipping, diptank,
soaking or immersion) range from levels of 7.5 % a.i. up to 32 % a.i.,
based on the level of protection needed and treatment duration.  Dip
treatments are specified for 1-3 to 30 minutes per inch of wood
thickness, or from 12-48 hours for heavy wooden members. Typical
use-rate levels are closer to 17% - 25% a.i.  As conservative estimates,
the typical high-end and the maximum levels cited on labeling for this
use were assessed as 25% and 32% a.i.. EPA Reg. No.1022-409 is a 25%
a.i. RTU product and EPA Reg. No. 9630-31 is a 63% a.i. concentrate
requiring dilution to yield a 32% a.i. treatment solution prepared by
blending the concentrate with two parts solvent [i.e., 1:2 v/v use
dilution * 63% a.i. in product = 31.5 (32 % a.i.].  Both product labels
cite use of eye protection (goggles/face shield) and
rubber/chemical-resistant gloves as PPE.  Also they include a
respirator-use PPE statement as follows: “Wear a NIOSH/MHSA-approved
mist/vapor respirator when spraying for continued or prolonged use of
this product or for frequent use of the product.”

	The exposure data for diptank operators wearing gloves were converted
into “unit exposures” in terms of mg a.i. for each 1% of
concentration of the product. The calculation of the inhalation unit
exposure of 0.046 mg/1% solution is presented in Table C-2 in
Appendix C.  The air concentrations presented in the DDAC study were
converted to unit exposures using an inhalation rate of 1.0 m3/hr (light
activity) and a sample duration of 8 hrs/day.

The following equations are used to estimate dermal and inhalation
handler exposure:

Daily Dose = DDAC UE * AI * AB

		BW

Where

DDAC UE	=	DDAC dermal or inhalation unit exposure (mg/ 1% in solution);

AI		=	AI (25 % or 32% a.i. in solution/day);

	AB		=	Absorption factor (NA for dermal,100% for inhalation); and

BW		=	Body weight (70 kg).

	Table 7.5 provides the short-, intermediate- and long-term doses and
MOEs for diptank operators.  The IT dermal MOEs are below the Agency
target of 100 (ranging from 70-90 for 32% and 25% a.i. products
respectively) and therefore denote potential dermal risk concerns.  The
inhalation ST/IT/LT MOEs are above the Agency target of 1,000, and not
of concern.  Therefore, a confirmatory inhalation toxicity study is not
warranted based on the results of this exposure scenario.

 Table 7.5.  Short-, Intermediate-, and Long-Term Exposures and MOEs
for Diptank Operators

Exposure Scenarioa

(number of replicates)	Dermal Unit Exposureb

(mg DDAC/1% solution)	Inhalation Unit Exposureb

(mg DDAC/1% solution)	App Rate

(% a.i. in solution/ day)c 	Absorbed Daily Doses d

(mg/kg/day)	MOEs e

Dermal	Inhalation	Dermal

IT

Target MOE = 100	Inhalation

ST/IT/LT

Target MOE = 1000

Occupational Handler

Dipping, with gloves (n=7)

	2.99	0.046	32 and 25	1.07-1.37	0.016-0.021	70-90	1,400-1,900

ST = 	Short-term duration;  IT =Intermediate-term duration; and LT =
long-term.

a. 	The exposure scenario represents a worker wearing long-sleeved
shirts, cotton work trousers, and gloves. Gloves were worn only when
near the chemical, not when operating the diptank.

b.	Dermal and inhalation unit exposures are from DDAC study (MRID
455243-04). Refer to Table B-2 in Appendix B for the dermal and
inhalation unit exposure calculations. Inhalation exposure (mg) was
calculated using the following equation: Air concentration (mg/m3) x
Inhalation rate (1.0 m3/hr) x Sample Duration (8 hr).  The inhalation
rate is from USEPA, 1997.

c.	The typical high-end and maximum application rates for dip
application method are 25% (1022-409) and 32% a.i. (9630-31) solutions.

d.	Absorbed Daily dose (mg/kg/day) = unit exposure (mg/1% a.i. solution)
* percent active ingredient in solution (25 or 32) * absorption factor
(NA for dermal and 100% for inhalation) / body weight (70 kg).

e.			MOE = NOAEL (mg/kg/day) / Daily dose [Where IT NOAEL = 100
mg/kg/day for dermal and ST/IT/LT NOAEL = 30 mg/kg/day for inhalation].
Target MOE is 100 for dermal exposure and 1,000 for inhalation exposure.

Construction Workers

	There are insufficient data to estimate the amount of exposure
associated with construction workers who install treated wood.  In
particular, values for the transfer coefficient associated with a
construction worker handling the wood could not be determined. However,
it is believed that the construction worker using a trim saw will have
larger dermal and inhalation exposures than the installer, due to the
amount of sawdust generated and the greater amount of hand contact that
would be necessary to handle the wood when using a saw compared to
installing the wood.

		7.4.2	Pressure Treatment Scenarios (Handler and Post-Application)  tc
\l3 "6.4.2	Pressure Treatment Scenarios (Handler and Post-application)

	Wood preservatives with Naphthenate Salts may be used to treat wood and
wood products using pressurized application methods, specifically
double-vacuum and full-cell pressure impregnation techniques which may
include thermal applications to condition the wood.  Registered product
use-rates for pressure treatment are at levels of 2% to 13% Naphthenate
Salts.  Typical use-rates contain 4 % to 13% a.i. in solvent-, oil- or
water-borne use-dilutions; resulting in 0.5% to 1.5% Copper (as metal),
in the solutions used for treatment.  The highest use rates are with
Copper Naphthenate products. The ratio of Copper metal to Copper
Naphthenate on most labels where Copper content is specified for
pressure treatment is about 1:8 , although the calculated ratio can
vary. The maximum rate of application used in this assessment is a 13 %
a.i. solution based on product labeling for EPA Reg. No. 43437-4, which
is an 89% a.i. concentrate for dilution with a hydrocarbon or petroleum
solvent. The label for this product indicates that pressure treatment
use solutions should be prepared by blending the concentrate with seven
parts solvent [i.e., 1:7 v/v use dilution * 89% a.i. in product = 12.7
(13 % a.i. in solution during application].  In comparison, where water
dilutions are made, the highest use-rate concentration is 10% a.i. for
EPA Reg. No. 1022-568.

	The Naphthenate Salts are listed in the American Wood-Preservers’
Association (AWPA) Book of Standards for treating major softwood species
used for a variety of wood products (e.g., Douglas-fir and Southern
yellow pine). It is unclear if any hardwood species are pressure-treated
using Copper/Zinc Naphthenates. The minimum Copper Naphthenate
retentions (as elemental copper) range from 0.64 kg/m3 (0.04 lb/ft3) for
wood used above ground, to 0.96 kg/m3 (0.06 lb/ft3) for wood used in
soil (ground) and fresh water contact, 1.2 kg/m3 (0.075 lb/ft3) for wood
used in critical structural applications, 1.60 kg/m3 (0.10 lb/ft3) for
pilings (soil, fresh water and foundation), and up to 2.4 kg/m3 (0.15
lb/ft3) for utility poles.

	Chemical-specific exposure data are not available on Naphthenate Salts
for assessment of pressure treatment exposure.  Therefore, the
assessment relies on surrogate Chromated Copper Arsenate (CCA) data
(ACC, 2002) and was based on the approach used in a previous Agency
exposure assessment (USEPA, 2003).

Surrogate Unit Exposure Data

	Dermal and inhalation exposures for pressure treatment uses are derived
from information in the exposure study sponsored by the American
Chemistry Council (2002) entitled “Assessment of Potential Inhalation
and Dermal Exposure Associated with Pressure Treatment of Wood with
Arsenical Wood Products” (ACC, 2002). In this study, a treatment
solution of CCA was approximately 0.5 percent active ingredient. The CCA
exposure monitoring study has been reviewed by the Agency and is
considered a valid surrogate source of data for pressure treatment
applications and is therefore used in estimating exposure to Naphthenate
Salts.

small (5 ≤ n ≤ 15).

	The measured CCA dermal and inhalation exposure values were normalized
by the treatment solution concentration used at each of the 3 facilities
(i.e., unit exposure reported as µg arsenic/ppm treatment solution).
Table 7.6 presents the dermal and inhalation unit exposure values
normalized to the treatment solution concentration in ppm for (1) all
sites, (2) treatment operator (TA handler), (3) treatment assistant (TA
handler), and (4) all post-application job functions (TS, SO, LO, S, TB,
TM). The normalization by treatment solution concentration was performed
to extrapolate the measured exposures in the CCA study (monitored at
~0.5% a.i. solution) to the maximum Naphthenate Salts treatment solution
concentration from EPA Reg. No. 43437-4 (13 % a.i. solution) (Shown in
Table 7.7).

Table 7.6.  Dermal and Inhalation Exposure Values from a CCA Pressure
Treatment Study (Exposure Data used as Surrogate Unit Exposures for
Naphthenate Salts Assessment)

Site	Treatment Solution  	Statistic	Dermal Unit Exposure

((g As/ppm)	Air

Concentrationb

((g As/m3/ppm)	Inhalation Unit Exposurec

((g As/ppm)

	%	ppma

All sites - All Data

(n = 64)	0.438 to 0.595	4,380 to 5,950	Average ± std	0.97 ± Unknown
0.00013 ± 0.00023	0.00104

	Median	0.36	0.00013	0.00104

	90th percentile	2.07	0.00077	0.00617

	Maximum	7.74	0.0011	0.00882

All sites - Handler Treatment Operator

(n = 15)	0.438 to 0.595	4,380 to 5,950	Average ± std	2.04 ± 2.68
0.00032 ± 0.00038	0.00257

	Median	0.37	0.00013	0.00104

	90th percentile	5.39	0.00092	0.00737

	Maximum	7.74	0.0011	0.00882

All sites - Handler Treatment Assistant

(n = 10)	0.438 to 0.595	4,380 to 5,950	Average ± std	0.24 ± 0.14
0.0001 ± 0.00004	0.000802

	Median	0.23	0.00013	0.00104

	90th percentile	0.40	0.00013	0.00104

	Maximum	0.52	0.00014	0.00112

All sites – Post-application: All job functions (TS, SO, LO, S, TB,
TM)

(n = 39)	--	--	Average ± std	0.74 ± 0.73	0.00020 ± 0.00025	0.00160

	Median	0.42	0.00013	0.00104

	90th percentile	1.81	0.00050	0.00401

	Maximum	3.11	0.0011	0.00882

	a.	ppm = (% treatment solution) * (10,000).

	b.	Air concentration was calculated as (g collected per sample per ppm
/ (480 min per day x 2 L/min).

	c.	Inhalation unit exposure = air concentration ((g As/m3/ppm) *
breathing rate for light activities (0.0167 m3/min) * 	sample duration
(480 min).  Values shown in bold are used for the assessment.

Exposure Calculations

The following equation was used to estimate dermal and inhalation
exposure:

Absorbed Daily Dose = 	UE * AI * AB

	      	       BW

Where

UE	=	Unit exposure (mg As/ppm);

AI	=	Percent active ingredient (13 % a.i. in solution);

AB	=	Absorption factor (Not applicable [NA] for dermal, 100% for
inhalation); and

BW	=	Body weight (70 kg).

Results

	The estimated dermal and inhalation exposures and MOEs for Naphthenate
Salts pressure treatment uses are presented in Table 7.7. The calculated
IT dermal MOEs for both the treatment operator handler (MOE = 25) and
post-application workers (MOE = 70) were below the Agency target MOE of
100 and therefore represent potential risks of concern. The ST/IT/LT
inhalation MOEs for all scenarios are above the target MOE of 1,000 and
not of concern. In addition, because the MOE is greater than 1,000, a
confirmatory inhalation toxicity study is not warranted based on the
screening-level results.

Table 7.7.  Short-, Intermediate-, and Long-Term Exposures and MOEs for
Pressure Treatment Handler and Post-application Scenarios Related to
Naphthenate Salts Use

Exposure Scenarioa

Unit Exposurea

((g As/ppm)

Application Rate

(% ai solution) 	Absorbed Daily Dosesb

(mg/kg/day)	MOEsc

	Dermal	Inhalation

Dermal	Inhalation	Dermal

IT

Target = 100	Inhalation

ST/IT/LT

Target=1000

Occupational Handler

Treatment Operator (TO)	2.04	0.00257	13	4	0.0048	25	6,300

Treatment Assistant (TA)	0.24	0.000802	13	0.446	0.0015	220	20,000

Occupational Post-application

All Job Functions