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**UNITED STATES ENVIRONMENTAL PROTECTION AGENCY**

WASHINGTON, D.C. 20460

OFFICE OF

PREVENTION, PESTICIDES AND

TOXIC SUBSTANCES

September 29, 2005

**[MEMORANDUM]{.underline}**

**SUBJECT:** Revised Environmental Fate Assessment of 4-tert-Amylphenol
and its Potassium and Sodium salts for the Reregistration Eligibility
Decision (RED) Document

> **Case No.**: 3016 **DP Barcode:** 322006

**FROM:** Srinivas Gowda, Microbiologist/Chemist

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510C)

**TO:** Mark Hartman, Branch Chief

Benjamin Chambliss, Team Leader

Killian Swift, Chemical Review Manager

Regulatory Management Branch II

Antimicrobials Division (7510C)

Deborah Smegal, Risk Assessor

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510C)

**THRU:** Siroos Mostaghimi, Acting Team Leader, Team one

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510C)

Norman Cook, Branch Chief

Risk Assessment and Science Support Branch (RASSB)

Antimicrobials Division (7510C)

**[Chemical Name]{.underline}** **[PC Code]{.underline}** **[CAS
\#]{.underline}** **[Common Name]{.underline}**

4-tert-Amylphenol 064101 80-46-6 p-tert-amylphenol

Potassium 4-tert-amylphenate 064111 53404-18-5 Potassium
p-tert-amylphenate

Sodium 4-tert-amylphenate 064112 31366-95-7 Sodium p-tert-amylphenate

Environmental Fate Science Chapter and Fate Assessment on
4-tert-Amylphenol and its potassium and sodium salts is submitted for
Reregistration Eligibility Decision (RED).

**EXECUTIVE SUMMARY**

**Environmental Fate Assessment:**

The environmental fate assessment for 4-tert-Amylphenol and its
potassium and sodium salts is based on US EPA=s Estimation Programs
Interface (EPI) Suite. EPI Suite provides estimations of
physical/chemical properties and environmental fate properties.

4-tert-Amylphenol may be bioaccumlative (log K~OW~ 3.91) and is likely
to pose a concern for aquatic organisms. It is expected to have moderate
to slight mobility in soils based upon the estimated Koc value of 3799.
Estimated value for biodegradation probability indicates that it may
biodegrade linearly within days in aquatic medium. However, ultimate
biodegradation (mineralization) may take months. Ready Biodegradability
study results also indicate that the relationship between biodegradation
of 4-tert-Amylphenol and time appears to be linier in an aqueous medium
and ultimate biodegradation would occur over a period longer than a
month. It is volatile and may vaporize into atmosphere. The estimated
half life in the air for 4-tert-Amylphenol is about three hours which
indicates that it is not persistent in air. Because of the possibility
of biodegradation in water and soils, it is not likely to contaminate
surface and ground waters.

p-tert-Amylphenol, potassium salt, is not likely to be bioaccumlative (
log K~OW~ 1.23) and may not pose a concern for bioconcentration in
aquatic organisms. It may be expected to have moderate to slight
mobility in soils as its estimated Koc value is 3799. Estimated
probability of biodegradation of p-tert-Amylphenol, potassium salt, in
soils and water indicates that it is likely to biodegrade within days to
weeks. Therefore, it may be unlikely that soil and water contamination
would take place. It has low volatility and its estimated half life in
air is about 4.68 hours and is not likely to be persistent in air.

p-tert-Amylphenol, sodium salt, is not likely to be bioaccumlative ( log
K~OW~ is 1.23) and may not pose a concern for bioconcentration in
aquatic organisms. It may be expected to have moderate to slight
mobility in soils as its estimated Koc value is the same as the parent
molecule, 4-tert-Amylphenol. Probability for Sodium 4-tert-amylphenate
biodegradation is the same as the parent molecule, 4-tert-Amylphenol.
Hence it is not likely to persist in soils and water, and surface and
ground water contamination is not likely to occur. It has low volatility
and its estimated half life in air is about 4.68 hours and is not likely
to be persistent in air.

**APPENDIX**

**Environmental Fate Science** **Chapter** **for para-tert-amylphenol**:

4-tert-Amylphenol is registered as an active product and is used as
bactericide/fungicide/fungistat. For the Reregistration Eligibility
Decision (RED) process the Agency used an in-house database program,
Estimation Programs Interface (EPI) Suite, and open literature (Toxnet)
to obtain fate properties of para-tert-Amylphenol. The Agency lacks
database on environmental fate/transport properties of
p-tert-Amylphenol. Hence Agency made use of the Windows based suite of
physical/chemical properties and environmental estimation models
developed by the US EPA=s Office of Prevention, Pesticides and Toxic
substances (OPPTS) and Syracuse Research Institute (SRC). The following
fate properties were obtained from EPI Suite and TOXNET.

1.  Vapor Pressure: 0.00116 mm Hg at 25^o^C ^(1)^

2.  Henry=s law Constant (air/water partition coefficient):2.03 x 10^-6^
    atm-m^3^/mole at 25^o^C ^(1)^

3.  Log K~OC~ (organic carbon ratio in soil): 3.57 (Koc: 3799 ) ^(1)^

4.  Log K~OW~ (octanol/water partition coefficient): 3.91 ^(1)^

5.  Water solubility: 113 mg/L ^(1)^

6.  Log bioconcentration factor (BCF) is 2.313 (BCF = 205.7) ^(1)^

7.  Medium to slight soil mobility. ^(1)^

    8\. May undergo direct air photolysis, half life in air (estimated)
    is 3.07 hours due to induced photochemical reaction of atmospheric
    hydroxyl radical ^(2)^

    9\. Abiotic Degradation: Phenols are generally resistant to aqueous
    environmental hydrolysis. Therefore, 4-tert-Amylphenol is not
    expected to hydrolyze in environmental media (SRC) ^(2)^

The estimated value for biodegradation probability indicates that
4-t-amylphenol may biodegrade linearly within days in aquatic medium.
However, ultimate biodegradation (mineralization) may take months.
Aquatic hydrolysis, oxidation, volatilization, bioconcentration, and
adsorption to sediment are not expected to be significant fate processes
for para-tert-Amylphenol because of its lack of hydrolyzable hydrogen.
Because of a low Henry=s Law Constant, volatilization of
para-tert-Amylphenol to partition from surface water to air is likely to
be minimum. Based upon Koc value of 3799, para-tert-Amylphenol has a
moderate to slight soil mobility. Adsorption to sediment is not expected
to be important fate process. The K~OW~ indicates that bioaccumulation
in aquatic organisms like fish is not likely. With a vapor pressure of
0.00116 mm Hg at 25^o^C para-tert-Amylphenol likely to vaporize easily
from soils and degrades rapidly by reaction with photochemically
produced hydroxyl radicals (half-life of \~3.07 hours) in air.

**Ready Biodegradability (OPPTS Guideline No. 835.3110, MRID No.
466247-01**) ^(3)^

This study was reviewed by the Agency, and satisfies the OPPTS 835.3110
guideline requirements for a biodegradation study. Biodegradability was
investigated under aerobic static exposure conditions using the CO~2~
Evolution Test.

Based on the data of the individual inorganic carbon determinations, the
mean biodegradability in the CO~2~ Evolution Test of p-tert-Amylphenol
was calculated to be 73% after 28 days. The biodegradation of
p-tert-Amylphenol reached 52% at the end of the 10-day window.
Significant biodegradation of the test substance was observed after a
lag phase of about 7 days. The procedural control, sodium benzoate,
reached 86% biodegradation after 14 days. This confirms the validity of
the test, as the OPPTS guidelines require that the procedural control
reach at least 60% degradation by day 14. p-tert-Amylphenol did not
reach the pass level of 60% for ready biodegradability in the CO2
Evolution Test within the 10-day window.

The results from the ready biodegradability study are consistent with
the above stated biodegradation statements based on the estimated value.
The relationship between biodegradation of the test chemical and time
appears to be linear based on inspection of the graph presented in the
ready biodegradation study report. The p-tert-Amylphenol was found not
to be readily biodegradable. Over the 28-day test period, 73%
degradation had occurred, suggesting that ultimate biodegradation would
occur over a period longer than a month.

**Surface water and Ground Water Contamination**:

4-tert-Amylphenol has been found in an effluent sample from a municipal
waste water treatment plant. However, the estimated value for
biodegradation indicates it may biodegrade linearly within days in the
aquatic environment. Ultimate biodegradation (mineralization) may take
months. It is also volatile based on its vapor pressure of 0.00116 mmHg,
and has a moderate to slight mobility in soils based on its estimated
Koc value of 3799. Thus, it is not likely to contaminate surface and
ground waters.

**Environmental Fate Science Chapter For para-tert-Amylphenol, potassium
salt:**

p-tert-Amylphenol, potassium salt, is registered as an active product.
For the Reregistration Eligibility Decision (RED) process the Agency
used an in-house database program, Estimation Programs Interface (EPI)
Suite, and open literature (Toxnet) to obtain fate properties of
p-tert-Amylphenol, potassium salt. The Agency lacks database on
environmental fate/transport properties of p-tert-Amylphenol. Hence
Agency made use of the Windows based suite of physical/chemical
properties and environmental estimation models developed by the US EPA=s
Office of Prevention, Pesticides and Toxic substances (OPPTS) and
Syracuse Research Institute (SRC). The following fate properties were
obtained from EPI Suite.

1\. Vapor Pressure: 7.7 x 10^-10^ mm Hg at 25^o^C ^(1)^

2\. Henry law Constant (air/water partition coefficient): 5.379 x
10^-14^ atm-m^3^/mole at 25^o^C ^(1)^

3\. Log K~OC~ (organic carbon ratio in soil): 3.57 (K~OC~: 3799) ^(1)^

4\. Log K~OW~ (octanol/water partition coefficient): 1.23 ^(1)^

5\. Water solubility: 3811 mg/L ^(1)^

6\. Log bioconcentration factor (BCF) is 2.313 (BCF = 205.7) ^(1)^

7\. Medium to slight mobility in soil. ^(1)^

8\. May undergo direct air photolysis, half life in air (estimated) is
4.68 hours due to induced photochemical reaction of atmospheric hydroxyl
radical.^(1)^

Estimated probability of biodegradation of p-tert-Amylphenol, potassium
salt, in soils and water indicates that it is likely to biodegrade
within days to weeks. Aquatic hydrolysis, oxidation, volatilization,
bioconcentration, and adsorption to sediment are not expected to be
significant fate processes for p-tert-Amylphenol, potassium salt,
because of its lack of hydrolyzable hydrogen. Because of a low Henry=s
Law Constant, volatilization of p-tert-Amylphenol, potassium salt, to
partition from surface water to air is likely to be minimum. Koc value
of 3799 indicates that para-tert-Amylphenol, potassium salt, has a
moderate to slight soil mobility. The K~OW~ indicates that
bioaccumulation in aquatic organisms like fish is not likely. The
estimated BCF (205.7) value indicates that bioaccumulation is likely be
low. p-tert-Amylphenol, potassium salt degrades rapidly by reaction with
photochemically produced hydroxyl radicals (half-life of \~4.68 hours)
in air.

**Surface Water and Ground Water Contamination:**

Due to a Koc value of 3799, p-tert-Amylphenol, potassium salt, has a
moderate to slight mobility in soil. Biodegradation of
p-tert-Amylphenol, potassium salt, is likely, based on estimated high
probability of linear biodegradation. Estimated probability of
biodegradation of p-tert-Amylphenol, potassium salt, in soils and water
indicates that it is likely to biodegrade within days to weeks. Thus, it
is unlikely that there will be soil and water contamination.

**Environmental Fate Science Chapter For para-tert-Amylphenol, sodium
salt:**

p-tert-Amylphenol, sodium salt, is registered as an active product. For
the Reregistration Eligibility Decision (RED) process the Agency used an
in-house database program, Estimation Programs Interface (EPI) Suite,
and open literature (Toxnet) to obtain fate properties of
p-tert-Amylphenol, sodium salt. The Agency lacks database on
environmental fate/transport properties of p-tert-Amylphenol. Hence
Agency made use of the Windows based suite of physical/chemical
properties and environmental estimation models developed by the US EPA=s
Office of Prevention, Pesticides and Toxic substances (OPPTS) and
Syracuse Research Institute (SRC). The following fate properties were
obtained from EPI Suite.

1\. Vapor Pressure: 7.7 x 10^-10^ mm Hg at 25^o^C ^(1)^

2\. Henry law Constant (air/water partition coefficient): 4.10 x 10^-14^
atm-m^3^/mole at 25^o^C ^(1)^

3\. Log K~OC~ (organic carbon ratio in soil): 3.57 (K~OC~: 3799) ^(1)^

4\. Log K~OW~ (octanol/water partition coefficient): 1.23 ^(1)^

5\. Water solubility: 4595 mg/L ^(1)^

6\. Log bioconcentration factor (BCF) is 2.313 (BCF = 205.7) ^(1)^

7\. Medium to slight mobility in soil. ^(1)^

8\. May undergo direct air photolysis, half life in air (estimated) is
4.68 hours due to induced photochemical reaction of atmospheric hydroxyl
radical.^(1)^

Estimated probability of biodegradation of p-tert-Amylphenol, sodium
salt, in soils and water indicates that it is likely to biodegrade
within days to weeks. Aquatic hydrolysis, oxidation, volatilization,
bioconcentration, and adsorption to sediment are not expected to be
significant fate processes for p-tert-Amylphenol, sodium salt, because
of its lack of hydrolyzable hydrogen. Because of a low Henry=s Law
Constant, volatilization of p-tert-Amylphenol, sodium salt, to partition
from surface water to air is likely to be minimum. Koc value of 3799
indicates that para-tert-Amylphenol, sodium salt, has a medium to slight
soil mobility. The K~OW~ indicates that bioaccumulation in aquatic
organisms like fish is not likely. The estimated BCF (205.7) value
indicates that bioaccumulation is likely be low. p-tert-Amylphenol,
sodium salt, degrades rapidly by reaction with photochemically produced
hydroxyl radicals (half-life of \~4.68 hours) in air.

**Surface Water and Ground Water Contamination:**

Due to a Koc value of 3799, p-tert-Amylphenol, sodium salt, has a
moderate to slight mobility in soil. Biodegradation of
p-tert-Amylphenol, sodium salt, in soil is likely, based on the
estimated high probability of linear biodegradation. Estimated
probability of biodegradation of p-tert-Amylphenol, sodium, in soils and
water indicates that it is likely to biodegrade within days to weeks.
Thus, it is unlikely that there will be soil and water contamination.

**[Data Gap]{.underline}:**

Para-tert-amylphenol and its potassium and sodium salts are registered
as indoor use products and minimum environmental fate data required by
EPA for an indoor use product is hydrolysis (161-1). However, no
hydrolysis data as indicated in the U.S. Environmental Protection
Agency's Environmental Fate Data Requirements published in Pesticide
Assessment Guidelines, Subdivision N, §161-1 have been submitted to the
Agency for these chemicals.

**BIBLIOGRAPHY**

**MRID** **Citation**

\-\-\-\-\-\-\-\-\-\-\-\-\-- (1) The Estimation Programs Interface (EPI)
Suite. Windows based suite of physical/chemical properties and
environmental estimation models developed by the US EPA=s Office of
Prevention, Pesticides and Toxic substances (OPPTS) and Syracuse
Research Institute (SRC).
http://www.epa.gov/opptintr/exposure/docs/EPISuitedl.htm

\-\-\-\-\-\-\-\-\-\-\-\-- (2) Hazard Substances Databank (HSDB). A
Database of the National Library of Medicine=s TOXNET System.

46624701 (3) Haner, A. 1999. p-tert.-Amylphenol: Ready Biodegradability
-- Evaluation of the Aerobic Biodegradability in an Aqueous Medium: OECD
301 B: CO~2~ Evolution Test. Report No. 427/b-99. Unpublished study
prepared by BMG Engineering Ltd., Schlieren for Clariant Corporation,
Charlotte, NC