Unitwl States t Office of Water
Envronmental Protection 4303 July 1995
Agency
10058
Fact Sheet oğl ?
Proposed Test Procedure for the Analysis of Oil
and Grease and Total Petroleum Hydrocarbons
BACKGROUND
The discharge of chlorofluorocarbons (CFCs) has
been shown to be a primary contributor to the depletion
of the earth's stratospheric ozone layer. The United
States, as a party to the Montreal Protocol on
Substances that Deplete the Ozone Layer and as required
by law under the Clean Air Act Amendments of 1990
(CAAA), is committed to controlling and eventually
phasing out CFCs.
Freon-113 is a Class I CFC that is required for
use in several U.S. Environmental Protection Agency
(EPA) wastewater methods for the determination of oil
and grease and total petroleum hydrocarbons (TPH).
Both analytes are included in various regulatory
compliance monitoring programs and are therefore
measured on a regular basis.
As part of the effort to eliminate the use of
CFCs, EPA studied the use of solvents alternative to
Freon-113 for determination of oil and grease and TPH.
As a result of these studies, EPA has concluded that n-
hexane is the most suitable replacement for Freon-113
in the separatory funnel extraction and gravimetric
determination of oil and grease and TPH. Therefore EPA
Method 1664: N-Hexane Extractable Material (HEM) and
Silica Gel Treated N-Hexane Extractable Material (SGT-
HEM) by Extraction and Gravimetry (Oil and Grease and
Total Petroleum Hydrocarbons) is being proposed to
replace currently approved methods for the
determination of oil and grease and to provide a method
for TPH. Current 40 CFR 136 approved methods that
would be replaced by Method 1664 include EPA Method
413.1 and Standard Method 5520B, both of which use
Freon-113 as the extraction solvent.
On May 10, 1995, an exemption for laboratory and
analytical essential uses of CFCs was granted through
the 1997 control periods (60 FR 24970). This proposed
rule will provide for the eventual elimination of the
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elimination of the use of Freon-113 consistent with the
goals of the CAAA and the Montreal Protocol.
The proposal of Method 1664 is pursuant to the
authority of sections 301, 304(h), and 501(a) of the
Clean Water Act (CWA) . Test methods are promulgated at
40 CFR Part 136.
METHOD 1664
Method 1664, which uses n-hexane as the extraction
solvent in place of Freon-113, is a liquid/liquid
extraction, gravimetric procedure applicable to aqueous
matrices for the determination of n-hexane extractable
material and silica gel treated n-hexane extractable
material (oil and grease and TPH, respectively).
The most significant changes in Method 1664
compared to other oil and grease and TPH methods that
use separatory funnel extraction and gravimetric
determination are 1) the use of n-hexane as the
extraction solvent, 2) the use of standards of known
composition and purity, specifically hexadecane and
stearic acid, as the spiking materials for QC analyses,
and 3) the introduction of extensive quality control
(QC) . Though not specifically incorporated into Method
1664, the use of alternative extraction and
concentration techniques, such as solid phase
extraction (SPE), are allowed under the performance-
based option of this method, provided that all
performance specifications in the Method are met.
REQUIREMENTS OF THE REGULATION
This proposal amends the Guidelines Establishing
Test Procedures for the Analysis of Pollutants under
section 304(h) of the Clean Water Act to replace
currently approved gravimetric test procedures with EPA
Method 1664 for determination of the conventional
pollutant "oil and grease" and a non-conventional
pollutant, TPH. This rule is necessary to meet
compliance monitoring requirements of the Clean Water
Act and, though the May 10, 1995 final rule concerning
the protection of the stratospheric ozone (60 FR 24970)
provides a global exemption for laboratory use of CFCs
through 1997, serves to comply with the CFC phaseout
objectives of the Clean Air Act Amendments of 1990.
This proposal solicits comments on the replacement
of Freon-113 with n-hexane, the utility of Method 1664
for monitoring, the QC acceptance criteria, the MDL and
ML levels, and the performance-based option criteria
for the use of alternative extraction and concentration
techniques, such as SPE. The proposed rule applies to
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any permits and regulations requiring the determination
of oil and grease by 40 CFR 136 approved methods.
REGULATORY IMPACTS
Use of the proposed method will affect any
permittee regulated for oil and grease. Since oil and
grease is a method defined parameter, any change in
method protocol, such as the use of another solvent,
has the potential to affect results. Evaluation of
results generated from Phase II of EPA's Freon
Replacement Study, however, indicates that any change
in oil and grease concentration that may result from
using n-hexane instead of Freon-113 would be
overshadowed by the variability that was observed in
the pre-existing approved Freon methods that did not
impose the thorough QC requirements imposed by Method
1613. Therefore, EPA does not believe that the
proposed change in solvent will subject permittees to
a greater risk of noncompliance than already exists.
An assessment of the regulatory impact
demonstrates that this proposed regulation would not be
considered a major regulation. The Agency believes
that the transitional costs associated with this
proposal will be minimal because laboratory testing is
a very small part of Freon-113 consumption (less than
I percent) and the testing required by EPA is only a
fraction of this total. Furthermore, the rule is not
likely to cause a major increase in costs or prices for
individuals or consumers, although laboratories may
experience some increase in costs due to longer testing
procedures because of the increased number of sample
manipulations and the additional quality control in the
method. The regulation is also unlikely to cause
significant adverse effects on competition, investment,
innovation, or international trade.
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