Document ID: EPA-HQ-OPP-2006-0831-0010
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-02-21T05:00Z

February 14, 2006

MEMORANDUM

SUBJECT:	Propylene/Dipropylene Glycol Revised Ecological Hazard and
Environmental Risk Characterization Chapter for the Reregistration
Eligibility Decision (RED) Document, Case 3126

TO:		Sanyvette Williams-Foy, Science Coordinator

Immediate Office

Antimicrobials Division (7510C)

And

Ben Chambliss, Team Leader

Connie Welch, Branch Chief

Regulatory Management Branch II

Antimicrobials Division (7510C)

FROM:	Kathryn Montague, M.S., Biologist

Risk Assessment and Science Support Branch

Antimicrobials Division (7510C)

THRU:	Siroos Mostaghimi, Team Leader

Norm Cook, Branch Chief

Risk Assessment and Science Support Branch

Antimicrobials Division (7510C)

Attached is the revised Propylene/Dipropylene Glycol ecological hazard
and environmental risk characterization for incorporation into the RED
document.

ECOLOGICAL HAZARD AND ENVIRONMENTAL RISK ASSESSMENT

Propylene and Dipropylene Glycol

Case No. 3126

(PC CODE 068603 and 068604)

February 14, 2006

Table of Contents

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  1

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

a.  Toxicity to Terrestrial Animals . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . .1

1.  Birds, Acute and Subacute . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . 1

2. Mammals, Acute and Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . .2

b.  Toxicity to Aquatic Animals . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.  Freshwater Fish, Acute . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . .3

2.  Freshwater Invertebrates, Acute . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .4

3.  Estuarine and Marine Organisms, Acute . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . 5

4.  Aquatic Organisms, Chronic . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . .6

c.  Toxicity to Plants . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.  Risk Assessment and Risk Characterization . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

a.  Environmental Fate Assessment Summary . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .8

b.  Environmental Exposure Assessment . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .9

c.  Environmental Risk Assessment . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .9

d.  Endangered Species Considerations . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .10

3.  References . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . . .. . .
.  12

	Ecological Effects Hazard and Environmental Risk Assessment

	Propylene and Dipropylene Glycol

Executive Summary:

Propylene glycol is used as an active pesticidal ingredient for the
following use patterns:  air sanitizer, insecticide, fungicide,
acaricide, antibacterial cleaner, and tuberculocide in residential areas
and hospitals.  Dipropylene glycol is used as a fungicide, medical
disinfectant, sanitizer and virucide in residential areas and hospitals.
 All registered pesticidal uses of these two chemicals are indoor. 
There are also non-pesticidal uses of both propylene and dipropylene
glycol, e.g., solvents and de-icing fluids, and propylene glycol is also
used as an inert ingredient in certain pesticide formulations (Quintec,
for fungicidal application on cherry, grapes and hops, preharvest).

Both propylene glycol and dipropylene glycol show very low acute
toxicity to terrestrial and aquatic animals.  No data were available to
address the chronic toxicity of either chemical to animals or acute or
chronic toxicity to plants.

Environmental exposure from the registered uses of propylene and
dipropylene glycol should be minimal. No environmental modeling was
performed, as these uses are all indoors. The lack of exposure coupled
with the very low toxicity of these compounds indicates that acute risk
to terrestrial and aquatic animals should not occur from the registered
uses of these chemicals.  No data were available to address the risk to
plants, but exposure to plants is not expected from the registered uses
of propylene and dipropylene glycol.  Environmental modeling was
conducted for the inert use of propylene glycol in pesticide
formulations (see memo from A. Najm Shamim), and the estimated exposure
was compared to the available acute toxicity information for birds,
mammals, fish, and aquatic invertebrates.  The resulting risk quotients
(RQs) were all below acute Agency levels of concern (LOCs) for birds,
mammals, fish and aquatic invertebrates. Chronic risk and risk to plants
could not be assessed due to a lack of chronic toxicity and
phytotoxicity information.

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(  (NE) determination.  The active ingredient uses of 
propylene and dipropylene glycol fall into this category.

Exposure to nontarget organisms from the inert use of propylene glycol
in pesticide formulations was assessed.  Resulting RQs were well below
acute LOCs for endangered birds, mammals, fish and aquatic
invertebrates.  Therefore, the inert uses of propylene glycol are also
considered to have no effect (NE) on listed species in those taxa.  Risk
to plants cannot be addressed at this time due to a lack of
phytotoxicity data.

A.	Ecological Toxicity Data

  The toxicity endpoints presented below are based on the results of
toxicity studies submitted by registrants to meet the Agency(s
ecological effects data requirements for the uses of propylene glycol
and dipropylene glycol. Additional information was located in
EPA/ORD’s ECOTOX database, which provides summary endpoints from the
open scientific literature as well as studies submitted to the Agency. 

1.	Toxicity to Terrestrial Animals

(a)  Birds, Acute and Subacute

In order to establish the toxicity of propylene glycol and dipropylene
glycol to birds, the Agency required an acute oral toxicity study using
the technical grade of the active ingredient (TGAI).  The preferred test
species is either mallard duck (a waterfowl) or bobwhite quail (an
upland game bird).  The results of submitted studies are provided in the
following tables (Table 1 and 2).

Table 1.  Acute Oral Toxicity of Propylene Glycol to Birds

Species

	

% Active Ingredient (ai)	

Endpoint

(mg/kg)	

Toxicity Category (TGAI)	

Satisfies Guidelines/

Comments	

Reference

Northern bobwhite

(Colinus virginianus)	

100		

LD50 > 2000

NOEL = 2000	

Practically non- toxic	

Yes	

Campbell and Beavers, 1995

MRID#43762301

Northern bobwhite

(Colinus virginianus)	

99.88	

LD50 > 2150

NOEL = 2150	

Practically non-toxic	

Yes	

Pedersen, 1995

MRID #43888002

The results indicate that propylene glycol is practically non-toxic to
birds on an acute oral basis. The studies are acceptable and fulfill
guideline requirements (71-1/OPPTS 850.2100).

Table 1.  Acute Oral Toxicity of Dipropylene Glycol to Birds

Species

	

% Active Ingredient (ai)	

Endpoint

(mg/kg)	

Toxicity Category (TGAI)	

Satisfies Guidelines/

Comments	

Reference

Northern bobwhite

(Colinus virginianus)	

100		

LD50 > 2000

NOEL = 2000	

Practically non- toxic	

Yes

(  core study

(  14-day test duration	

Campbell and Beavers, 1995

MRID#43760807

The results indicate that dipropylene glycol is practically non-toxic to
birds on an acute oral basis. The study is acceptable and fulfills
guideline requirements (71-1/OPPTS 850.2100).

A subacute dietary study using the TGAI may be required on a
case-by-case basis depending on the results of lower tier ecological
studies and pertinent environmental characteristics to establish the
toxicity of a chemical to avian species.  This testing was not required
for propylene or dipropylene glycol. 

(b) Mammals

Table 3. Toxicity of Propylene Glycol to Mammals (excerpted from
Toxicology chapter)

Species

	

Test Type	

Results

Rat	

Acute oral	

LD50  8000 - 46000 mg/kg (toxicity category IV)

Rat	

15-week feeding	

NOAEC = 2500 mg/kg/day

Mouse	

Developmental	

maternal, reproductive, developmental NOAEL = 10400 mg/kg/day (oral)

Table 4. Toxicity of Dipropylene Glycol to Mammals (excerpted from
Toxicology chapter)

Species

	

Test Type	

Results

Rat	

Acute oral	

LD50 >5010 mg/kg (Toxicity category IV)

Mouse	

90-day - drinking water	

NOAEC = 4790mg/kg/day  male, 7430 mg/kg/day female

Rat	

Developmental	

reproductive, developmental NOAEL = 5000 mg/kg/day 

Both propylene and dipropylene glycol show low acute toxicity to mammals
in laboratory studies, and do not produce developmental or reproductive
effects at fairly high doses.

2.	Toxicity to Aquatic Animals

(a)	Freshwater Fish, Acute

In order to establish the acute toxicity of an indoor use antimicrobial
pesticide to freshwater fish, the Agency requires a freshwater fish
toxicity study using the TGAI.  Data are generally required on only one
species for indoor use antimicrobial pesticides.  The preferred test
species are rainbow trout (a coldwater fish) or bluegill sunfish (a
warmwater fish). Fish acute testing was required for propylene glycol,
and was reserved for dipropylene glycol, depending upon the results of
the propylene glycol fish test.  No fish acute toxicity testing has been
submitted to the Agency. A survey of the EPA/ORD database ECOTOX
provided multiple freshwater fish acute toxicity endpoints for propylene
glycol, which are summarized in the table, below.

Table 5.  Acute Toxicity of Propylene Glycol to Freshwater Fish

Species

	

Endpoints	

Toxicity Category 	

Reference

Goldfish (Carassius auratus)		

Static 24 hr. LC50 >5000 ppm ai	

 Practically non-toxic	

Bridie et al., 1979 (ECOTOX reference #623)

Rainbow trout (Oncorhynchus mykiss)	

Static 24-hr LC50 = 50,000 ppm	

Practically non-toxic	

Majewski et al., 1978 (ECOTOX reference # 991)

Fathead minnow (Pimephales promelas)	

48 hr LC50 = 790 ppm	

Practically non-toxic	

Pillard, 1995

(ECOTOX reference #13727)

Fathead minnow (Pimephales promelas)	

96 hr LC50 = 710 ppm	

Practically non-toxic	

Pillard, 1995

(ECOTOX reference #13727)

Fathead minnow (Pimephales promelas)	

96 hr LC50 = 62,000 ppm ai	

Practically non-toxic	

Pillard, 1995

(ECOTOX reference #13727)

Table 6.  Acute Toxicity of Dipropylene Glycol to Freshwater Fish

Species

	

Endpoints

	

Toxicity Category 	

Reference

Goldfish (Carassius auratus)		

24 hr. LC50 >5000 ppm ai	

 Practically non-toxic	

Bridie et al., 1979 (ECOTOX reference #623)

The results indicate that propylene glycol and dipropylene glycol are
practically non-toxic to freshwater fish on an acute basis.  Since these
data are supplemental information, Guideline 72-1/850.1075 is not
fulfilled; however, since multiple published studies demonstrate very
low toxicity to freshwater fish, no further testing is required for
propylene glycol or dipropylene glycol.

(b)	Freshwater Invertebrates, Acute

The Agency requires a freshwater aquatic invertebrate toxicity study
using the TGAI to establish the acute toxicity of an antimicrobial
pesticide to freshwater invertebrates.  The preferred test species is
Daphnia magna.  Results of submitted studies for proylene glycol and
dipropylene glycol are provided in the following tables:

Table 7.  Acute Toxicity of Propylene glycol to Freshwater
Invertebrates

Species

	

% Active Ingredient (ai)	

Endpoints

(ppm)	

Toxicity Category (TGAI)	

Satisfies Guidelines/

Comments	

Reference

Waterflea

(Daphnia magna)	

100

	

48-hr. EC50> 110 ppm ai

NOEC = 110 ppm ai	

Practically non-toxic	

Yes	

Graves and Swigert, 1995.  MRID #437623-02

Waterflea

(Daphnia magna)	

99.76	

48-hr. EC50 >1000 ppm ai

NOEC = 1000 ppm ai	

Practically non-toxic	

Yes	

Collins, 1995

MRID #438880-03

The results of these studies indicate that propylene glycol is
practically non-toxic to freshwater invertebrates.  The Guideline
requirement has been fulfilled (850.1010/72-2). Additional data on the
acute toxicity of propylene glycol to freshwater invertebrates was
retrieved from the ECOTOX database.  This information is provided below:

Table 8.  Additional Data on the Acute Toxicity of Propylene Glycol to
Freshwater Invertebrates

Species

	

Endpoints

	

Toxicity Category 	

Reference

Waterflea (Ceriodaphnia dubia)	

48 hr. LC50 = 1020 ppm ; NOEC = 660 ppm	

 Practically non-toxic	

Pillard, 1995

(ECOTOX reference #13727)

Waterflea (Ceriodaphnia dubia)	

48 hr LC50= 18340 ppm ai; NOEC = 13020 ppm ai	

Practically non-toxic	

Pillard, 1995

(ECOTOX reference #13727)

Waterflea (Ceriodaphnia dubia)	

48 hr LC50 = 4919 ppm ai	

Practically non-toxic	

Cornell et al., 2000

(ECOTOX reference #48385)

Waterflea (Daphnia magna)	

48 hr EC50 > 10000 ppm	

Practically non-toxic	

Kuhn et al., 1989

(ECOTOX reference #846)

These results further indicate that propylene glycol demonstrates very
low toxicity to freshwater invertebrates.

Table 9.  Acute Toxicity of Dipropylene glycol to Freshwater
Invertebrates

Species

	

% Active Ingredient (ai)	

Endpoints

(ppm)	

Toxicity Category (TGAI)	

Satisfies Guidelines/

Comments	

Reference

Waterflea

(Daphnia magna)	

100

	

48-hr. EC50> 109 ppm ai

NOEC = 109 ppm ai	

Practically non-toxic	

Yes	

Graves and Swigert, 1995.  MRID #437608-08

The results of this study indicate that dipropylene glycol is
practically non-toxic to freshwater invertebrates.  The Guideline
requirement has been fulfilled (850.1010/72-2).

(c)	Estuarine and Marine Organisms, Acute

Acute toxicity testing with estuarine and marine organisms using the
TGAI is required when the end-use product is intended for direct
application to the marine/estuarine environment or effluent containing
the active ingredient is expected to reach this environment. Neither
propylene glycol nor dipropylene glycol have such uses on their labels,
so testing with marine/estuarine organisms is not required.  Some
information on the acute toxicity of propylene glycol to
marine/estuarine invertebrates was found in ECOTOX, and the results are
provided below:

Table 10. Acute Toxicity of Propylene Glycol to Marine/Estuarine
Organisms

Species

	

Endpoints

	

Toxicity Category 	

Reference

Brine Shrimp (Artemia salina)	

static 24 hr. LC50 > 10000 ppm	

 Practically non-toxic	

Price et al., 1974

(ECOTOX reference #2408)

The results of this study indicate that propylene glycol is practically
non-toxic to brine shrimp on an acute basis.

(d)  Aquatic Organisms, Chronic

Chronic toxicity testing (Fish early life stage, 850.1300/72-4a and
aquatic invertebrate life cycle, 850.1400/72-4b) is not required for the
currently registered uses of propylene glycol or dipropylene glycol. No
comparable endpoints were found in the ECOTOX database.

3.  Toxicity to Plants

Plant toxicity testing is not required for the currently registered uses
of propylene glycol or dipropylene glycol.  No phytotoxicity data were
found in the ECOTOX database.

B.  Risk Assessment and Characterization

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

       

           RQ = EXPOSURE/TOXICITY 

 

RQs are then compared to AD's levels of concern (LOCs).  These LOCs are
criteria used by OPP to indicate potential risk to nontarget organisms
and the need to consider regulatory action.  The criteria indicate that
a pesticide used as directed has the potential to cause adverse effects
on nontarget organisms.  LOCs currently address the following risk
presumption categories: (1) acute high - potential for acute risk is
high regulatory action may be warranted in addition to restricted use
classification; (2) acute restricted use - the potential for acute risk
is high, but this may be mitigated through restricted use
classification; (3) acute endangered species - the potential for acute
risk to endangered species is high, and regulatory action may be
warranted, and (4) chronic risk - the potential for chronic risk is
high, and regulatory action may be warranted.   Currently, AD does not
perform assessments for chronic risk to plants, acute or chronic risks
to nontarget insects, or chronic risk from granular/bait formulations to
mammalian or avian species.

The ecotoxicity test values (i.e., measurement endpoints) used in the
acute and chronic risk quotients are derived from the results of
required studies.  Examples of ecotoxicity values derived from the
results of short-term laboratory studies that assess acute effects are:
(1) LC50 (fish and birds) (2) LD50 (birds and mammals (3) EC50 (aquatic
plants and aquatic invertebrates) and (4) EC25 (terrestrial plants). 
Examples of toxicity test effect levels derived from the results of
long-term laboratory studies that assess chronic effects are: (1) LOEC
(birds, fish, and aquatic invertebrates) (2) NOEC (birds, fish and
aquatic invertebrates) and (3) MATC (fish and aquatic invertebrates). 
For birds and mammals, the NOEC value is used as the ecotoxicity test
value in assessing chronic effects.  Other values may be used when
justified.  Generally, the MATC (defined as the geometric mean of the
NOEC and LOEC) is used as the ecotoxicity test value in assessing
chronic effects to fish and aquatic invertebrates.  However, the NOEC is
used if the measurement endpoint is production of offspring or survival.

Risk presumptions, along with the corresponding RQs and LOCs are
tabulated below.

Risk Presumptions for Terrestrial Animals

Risk Presumption	

RQ	

LOC

Birds and Wild Mammals

Acute High Risk	

EEC1/LC50 or LD50/sqft2 or LD50/day3	

0.5



Acute Restricted Use	

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

0.2

Acute Endangered Species	

EEC/LC50 or LD50/sqft or LD50/day 	

0.1

Chronic Risk	

EEC/NOEC	

1

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

 2    mg/ft2             	3  mg of toxicant consumed/day

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

 

Risk Presumptions for Aquatic Animals	 

Risk Presumption	

RQ 	

LOC

Acute High Risk	

EEC1/LC50 or EC50	

0.5

Acute Restricted Use	

EEC/LC50 or EC50	

0.1

Acute Endangered Species	

EEC/LC50 or EC50	

0.05

Chronic Risk	

EEC/MATC or NOEC	

1

 1  EEC = (ppm or ppb) in water

Risk Presumptions for Plants	

	

Risk Presumption	

RQ	

LOC

Terrestrial and Semi-Aquatic Plants 

 tc \l2 "Terrestrial and Semi-Aquatic Plants  

Acute High Risk	

EEC1/EC25	

1

Acute Endangered Species	

EEC/EC05 or NOEC	

1

Aquatic Plants

 tc \l2 "Aquatic Plants 

Acute High Risk	

EEC2/EC50	

1

Acute Endangered Species	

EEC/EC05 or NOEC 	

1

1  EEC = lbs ai/A 

2  EEC = (ppb/ppm) in water 

1.  Environmental Fate Assessment Summary (excerpted from the
Environmental Fate Science Chapter of  this RED document)

Propylene Glycol is not bioaccumlative ( log KOW is -0.92).   It does
not hydrolyze and is very mobile in soils, but it  biodegrades in 4 days
in aerobic soils, and the registered pesticidal uses are not likely to
contaminate surface or ground water.  Its half life in air is about 32
hours (estimated) due to induced photochemical reaction with hydroxy
radical in the atmosphere and its presence in the atmosphere is not
likely a concern.

Dipropylene Glycol is not bioaccumlative ( log KOW is -1.07).  It does
not hydrolyze. It is highly miscible in water and has low binding
constant with soils and it is shown to be very mobile in soils..
Therefore, there is a potential for ground water and surface water
contamination if outdoor use occurs, but this is not likely from the
registered pesticidal uses.  Biodegradation of dipropylene glycol is
slow, according to aerobic biological screening tests.  Its half life in
air is about 13 hours (estimated) due to induced photochemical reaction
with hydroxy radical in the atmosphere and hence its presence in the
atmosphere is not likely to pose any problem.

2.  Environmental Exposure Assessment

Environmental exposure modeling was not conducted for the registered
pesticidal uses of propylene glycol or dipropylene glycol, as these uses
are all indoors and are not expected to result in any appreciable
environmental exposure. Environmental exposure will occur from the use
of propylene glycol as an inert ingredient in certain pesticide
formulations (inert in Quintec for fungicidal application on cherry,
grapes and hops, preharvest). Environmental exposure for the inert use
of propylene glycol was assessed (see attached memo from A. Najm
Shamim). Estimated peak surface water concentrations were 887.54 ppb,
and estimated annualized average concentrations were 11.07 ppb. Detailed
environmental modeling was not performed for the terrestrial exposure
from these uses; however, using a high exposure scenario of a 1 lb/A
application rate applied via broadcast spray to short grasses with no
environmental breakdown, an EEC of 240 ppm is obtained.  

3.  Environmental Risk Assessment

The pesticidal uses of propylene glycol and dipropylene glycol
considered in this RED make it unlikely that any appreciable exposure to
terrestrial or aquatic organisms would occur. The lack of exposure,
coupled with the very low toxicity of these compounds to birds, mammals,
and aquatic organisms, indicate very low ecological risk from their use.
Toxicity and risk to plants cannot be addressed at this time due to the
lack of phytotoxicity information; however, exposure to plants should
not occur from the registered, indoor uses of these chemicals.

The high terrestrial acute estimated exposure value of 240 ppm,
described above, is well below the levels causing acute toxic effects in
birds and mammals (avian acute oral LD50s > 2000 mg/kg; rat acute oral
>5010 mg/kg).  Acute RQs for birds and mammals of varying body size are
reported in the table, below:

Table 11: Acute RQs for Terrestrial Organisms Based on High Exposure
Estimate for the Inert Use of Propylene Glycol

Species	

Body weight (kg)	

Food Consumption (g/day)	

LD50

(mg/kg bw)	

EEC

(240 mg/kg x 1kg/1000g x Food Cons)	

RQ

[EEC/(LD50 x bw)]

Bobwhite quail	

0.170	

15.20	

2000	

3.648	

0.011

Field sparrow	

0.0139	

4.656	

2000	

1.116	

0.040

Mouse/shrew	

0.015	

14.25	

5010	

3.42	

0.046

Vole	

0.035	

5.25	

5010	

1.26	

0.007

Rat	

1.000	

30.0	

5010	

7.2	

0.001

No adverse acute effects to birds and mammals is anticipated from the
use of propylene glycol as an inert ingredient in Quintec applied
preharvest to hops, grapes, and cherries.

Estimated surface water concentrations from the inert use of propylene
glycol are well below levels of concern for nontarget aquatic organisms,
with RQs as follows:

Table 12: Acute RQs for Aquatic Organisms Based on Estimated Surface
Water Concentrations from the Inert Use of Propylene Glycol

Species	

Endpoint	

Estimated Surface Water Concentration	

Risk Quotient

Fathead minnow	

96-hour LC50 = 710 ppm	

Acute EEC = 887.54 ppb (0.9005 ppm)	

0.0013

Daphnid	

48-hr EC50 = 4919 ppm	

Acute EEC = 887.54 ppb (0.9005 ppm)	

0.00018

Brine Shrimp	

24-hour EC50 = 1000 ppm	

Acute EEC = 887.54 ppb (0.9005 ppm)	

0.0009

4.  Endangered Species Considerations

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

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

For certain use categories, the Agency assumes there will be minimal
environmental exposure, and only a minimal toxicity data set is required
(Overview of the Ecological Risk Assessment Process in the Office of
Pesticide Programs U.S. Environmental Protection Agency - Endangered and
Threatened Species Effects Determinations, 1/23/04, Appendix A, Section
IIB, pg.81).  Chemicals in these categories therefore do not undergo a
full screening-level risk assessment, and are considered to fall under a
(no effect(  (NE) determination.  The active ingredient uses of 
propylene and dipropylene glycol fall into this category.

Exposure to nontarget organisms from the inert use of propylene glycol
in pesticide formulations was assessed.  Resulting RQs were well below
acute LOCs for endangered birds, mammals, fish and aquatic
invertebrates.  Therefore, the inert uses of propylene glycol are also
considered to have no effect (NE) on listed species in those taxa.  Risk
to plants cannot be addressed at this time due to a lack of
phytotoxicity data.

REFERENCES

Submitted Data:

MRID#43760807.  Campbell and Beavers, 1995.  Acute oral toxicity of
dipropylene glycol to Northern bobwhite.  Unpublished data.

MRID #43760808.  Graves and Swigert, 1995.  Acute toxicity of
dipropylene glycol to the waterflea (Daphnia magna).								

MRID#43762301. Campbell and Beavers, 1995.  Acute oral toxicity of
propylene glycol to Northern bobwhite.  Unpublished data.

MRID #43762302.  Graves and Swigert, 1995.  Acute toxicity of propylene
glycol to the waterflea (Daphnia magna).  Unpublished data.

MRID #43888002.  Pedersen, 1995.  Acute oral toxicity of propylene
glycol to Northern bobwhite.  Unpublished data.

MRID #43888003. Collins, 1995. Acute toxicity of propylene glycol to the
waterflea (Daphnia magna).  Unpublished data.				

Published Data: 

Bridie, A.L., C.J.M. Wolff, and M. Winter.  1979.  The Acute Toxicity of
Some Petrochemicals to Goldfish.  Water Res. 13(7):623-626. (ECOTOX
reference #623).

Cornell, J.S., D.A. Pillard, and M.T. Hernandez. 2000.  Comparative
Measures of the Toxicity of Component Chemicals in Aircraft Deicing
Fluid.  Environ. Toxicol. Chem. 19(6):1465-1472. (ECOTOX reference
#48385).

Kuhn, R., M. Pattard, K. Pernak, and A. Winter. 1989.  Results of the
Harmful Effects of Selected Water Pollutants (Anilines, Phenols,
Aliphatic Compounds) to Daphnia magna.  Water Res. 23(4):495-499.
(ECOTOX reference #846).

Majewski, H.S., J.F. Klaverkamp, and D. P. Scott. 1978.  Acute Lethality
and Sub-Lethal Effects of Acetone, Ethanol, and Propylene Glycol on the
Cardiovascular and Respiratory Systems of Rainbow Trout. Water Res.
12(4):217-221. (ECOTOX reference # 991).

Pillard, D.A. 1995.  Comparative Toxicity of Formulated Glycol Deicers
and Pure Ethylene and Propylene Glycol to Ceriodaphnia dubia and
Pimephales promelas.  Environ. Toxicol. Chem. 14(2):311-315. (ECOTOX
reference #13727).

Price, K.S., G.T. Waggy, and R. A. Conway. 1974.  Brine Shrimp Bioassay
and Seawater BOD of Petrochemicals.  J. Water Pollut. Control Fed.
46(1):63-77.(ECOTOX reference #2408).

U.S. EPA.  2004.  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.

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