Guidelines Establishing Test Procedures for the Analysis of Oil and Grease and Total Petroleum Hydrocarbons

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: January 23, 1996 (Volume 61, Number 15)]
[Proposed Rules]
[Page 1730-1739]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]

ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 136

[FRL-5401-7]

Guidelines Establishing Test Procedures for the Analysis of Oil
and Grease and Total Petroleum Hydrocarbons

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

SUMMARY: This proposed regulation would amend the Guidelines
Establishing Test Procedures for the Analysis of Pollutants under
section 304(h) of the Clean Water Act to replace existing gravimetric
test procedures for the conventional pollutant ``oil and grease'' (40
CFR 401.16) with EPA Method 1664 as part of EPA's effort to reduce
dependency on the use of chlorofluorocarbons (CFCs). Method 1664 uses
normal hexane (n-hexane) as the extraction solvent in place of 1,1,2-
trichloro-1,2,2-trifluoroethane (CFC-113; Freon-113). CFC-113 is used
in currently approved 40 CFR Part 136 methods for the determination of
oil and grease. These methods are EPA Method 413.1 in Methods for
Chemical Analysis of Water and Wastes (EPA-600/4-79-020) and Method
5520B in Standard Methods for the Examination of Water and Wastewater,
18th edition. This proposal would withdraw approval of Methods 413.1
and 5520B to preclude the unacceptable inconsistency between results
produced by such methods and proposed Method 1664. In an effort to
provide for the use and depletion of existing laboratory stocks of
Freon-113, EPA plans to implement the required use of Method 1664 no
sooner than six months after the final rule is published in the Federal
Register. Method 1664 is also being proposed for the determination of
total petroleum hydrocarbons.

[[Page 1731]]

DATES: Comments on this proposal must be submitted on or before March
25, 1996.

ADDRESSES: Send written comments on the proposed rule to ``Method
1664'' Comment Clerk; Water Docket MC-4101; Environmental Protection
Agency; 401 M Street, SW.; Washington, DC 20460. Commenters are
requested to submit any references cited in their comments. Commenters
are also requested to submit an original and 3 copies of their written
comments and enclosures. Commenters who want receipt of their comments
acknowledged should include a self addressed, stamped envelope. All
comments must be postmarked or delivered by hand by March 25, 1996. No
facsimiles (faxes) will be accepted.
Data available: A copy of the comments and supporting documents
cited in this proposal are available for review at EPA's Water Docket;
401 M Street, S.W., Washington, DC 20460. For access to the Docket
materials, call (202) 260-3027 between 9 a.m. and 3:30 p.m. for an
appointment.
Electronic versions of Method 1664 will be available via the
Internet. EPA operates a ``public access server,'' also known as
``Earth 1,'' through which EPA will include all of the ways that copies
of the test method manual are available. The Office of Water will put
the directions about electronic retrieval of the test method manual on
EPA's Internet ``homepage.'' By doing so, persons interested in
electronic copies of the method may obtain copies by either (1)
retrieving the documents from EPA's file transfer protocol (FTP) site
on the Internet at ftp.epa.gov or gopher.epa.gov (2) retrieving the
documents by dial-in access at 919-558-0335.

FOR FURTHER INFORMATION CONTACT: Mr. Ben Honaker, Engineering and
Analysis Division (4303), USEPA Office of Science and Technology, 401 M
Street, S.W., Washington, DC, 20460, or call (202) 260-2272.

SUPPLEMENTARY INFORMATION:

I. Authority

A. Clean Water Act

Today's proposal is pursuant to the authority of sections 301,
304(h), and 501(a) of the Clean Water Act (CWA), 33 U.S.C. 1314(h),
1361(a) (the ``Act''). Section 301 of the Act prohibits the discharge
of any pollutant into navigable waters unless the discharge complies
with an NPDES permit, issued under section 402 of the Act. Section
304(h) of the Act requires the Administrator of the EPA to ``promulgate
guidelines establishing test procedures for the analysis of pollutants
that shall include the factors which must be provided in any
certification pursuant to section 401 of this Act or permit
applications pursuant to section 402 of this Act.'' Section 501(a) of
the Act authorizes the Administrator to ``prescribe such regulations as
are necessary to carry out his function under this Act.''
The Administrator also has made these test methods applicable to
monitoring and reporting of NPDES permits (40 CFR part 122,
Secs. 122.21, 122.41, 122.44, and 123.25), and implementation of the
pretreatment standards issued under section 307 of the Act (40 CFR part
403, Secs. 403.10 and 402.12).

B. Clean Air Act Amendments of 1990

Today's proposal is also consistent with sections 604, 606 and 608
of the 1990 Clean Air Act Amendments (CAAA) to phase out production of
Class I CFCs and reduce use and emissions of Class I CFCs to the lowest
achievable level, and with section 613 of the CAAA to reduce the
Federal procurement of products and services that employ Class I CFCs.

II. Background and History

A. Oil and Grease and Petroleum Hydrocarbons Testing

The background and history of the applicability of EPA's
Stratospheric Ozone Protection Program to analytical methods requiring
the use of CFCs in EPA regulatory programs was given in an earlier
proposal of an alternate test procedure for the determination of oil
and grease (56 FR 30519-30520, July 3, 1991).
As stated in the earlier proposal, preliminary efforts to find a
suitable replacement solvent for Freon-113 in the determination of oil
and grease were conducted by the Office of Research and Development's
Environmental Monitoring Systems Laboratory in Cincinnati, Ohio (EMSLCi).
Results of that study, presented in the document titled A Study to
Select a Suitable Replacement Solvent for Freon-113 in the Gravimetric
Determination of Oil and Grease by F.K. Kawahara, October 2, 1991,
suggested the use of an 80/20 mixture of n-hexane and methyl tertiary
butyl ether (MTBE) in place of Freon-113 for oil and grease
determination. This led to the proposal (56 FR 30519-30524, July 3,
1991) to replace Freon-113 with the n-hexane:MTBE mixture in CWA and
RCRA analytical methods for determination of oil and grease. Based on
comments received concerning this proposal, the EMSL-Ci study results,
and the need to further investigate alternative solvents, the Office of
Water and the Office of Solid Waste initiated a multi-phase Freon
Replacement Study.

Phase I of the Freon Replacement Study
Phase I of the Freon Replacement Study evaluated alternative
solvents and extraction systems for equivalency to the results produced
by Freon-113 across a range of real world effluent and solid waste
samples from a variety of industrial categories. More specifically,
Phase I focused on (1) the use of five alternative solvents for
gravimetric determination of oil and grease in aqueous samples by MCAWW
Method 413.1 (with modifications) and in solid samples by SW-846 Method
9071A (with modifications) and (2) the use of alternative techniques
for oil and grease analysis including sonication extraction, solid
phase extraction (SPE) using cartridges and disks, and a solvent/nondispersive
infrared technique. The five alternative solvents studied in
Phase I were n-hexane, methylene chloride (dichloromethane),
perchloroethylene (tetrachloroethene), DuPont 123 (2,2-dichloro-1,1,1-
trifluoroethane, a hydrofluorochlorocarbon), and the n-hexane:MTBE
80:20 mixture.
Results of the tests of gravimetric procedures in Phase I yielded
the following conclusions: n-hexane should be retained as a possible
extraction solvent for further study using gravimetric techniques;
perchloroethylene should be retained for consideration in the use of
infra-red techniques; and cyclohexane should be introduced for
consideration with gravimetric techniques based on its similarity to nhexane
and because of its lower neurotoxicity when compared to nhexane.

Results of tests of alternative techniques in Phase I indicated
that only sonication extraction of soil and other solids-containing
samples produced results equivalent to existing techniques that use
Freon-113. Specifics of the study design, results, and conclusions can
be found in the Preliminary Report of EPA Efforts to Replace Freon for
the Determination of Oil and Grease, September 1993, that is included
in the docket.
Prior to the commencement of Phase II of the study, two public
workshops were held, one on May 4, 1993, in Norfolk, VA and the other
on June 30, 1993, in Boston, MA. The objectives of these workshops were
to inform interested parties of the results from Phase I and related
studies, and to

[[Page 1732]]
provide a forum for the discussion of results, issues, and possible
solutions to the problem of finding a non-ozone-depleting substance
that would produce results identical to the results produced by CFC-
113. Detailed records of the information presented, which included data
from EPA, vendor, and laboratory representatives, as well as the
proceedings of the question and answer sessions, can be found in the
reports entitled Oil and Grease Workshop, Norfolk, Virginia, May 4,
1993 and Oil and Grease Workshop, Boston, Massachusetts, June 30, 1993
that are also included in the docket for today's proposed rule.
2. Phase II of the Freon Replacement Study
Based on the conclusions of Phase I of the Freon Replacement Study,
Phase II was designed to further assess the use of n-hexane as a
replacement solvent and to evaluate the use of cyclohexane as a
replacement solvent for oil and grease determination in aqueous samples
by MCAWW Method 413.1, with modifications to allow for solvent
densities less than the density of water. In addition, gravimetric
determination of ``petroleum hydrocarbons'' was evaluated by subjecting
the extracted oil and grease samples to the silica gel adsorption
procedure in Standard Methods for the Examination of Water and
Wastewater (Standard Methods) 5520F (with modifications). This
procedure removes non-aliphatic hydrocarbons such as detergents,
surfactants, fatty acids, aromatic hydrocarbons, heterocyclics, and
some chemical compounds containing nitrogen, phosphorus, and sulfur.
The final objectives of the Phase II study were to utilize these
results and comments to choose a replacement solvent and to document
the analytical protocol implemented to produce the first draft of
Method 1664 (the ``Method'') for gravimetric determination of oil and
grease and petroleum hydrocarbons. Following the formal documentation
of the Method, a further objective was to initiate an interlaboratory
study using the new method in order to characterize the method and
generate method specifications in the form of quality control (QC)
acceptance criteria.
A total of 34 samples from a combination of in-process and effluent
waste streams were collected from 25 facilities encompassing 16
different industrial categories. Samples containing between 40-300 mg/L
oil and grease, some from petroleum and some from non-petroleum
sources, were collected. The study focused on this concentration range
to avoid the problems associated with the comparison and evaluation of
``non-detect'' results. In order to increase the types of matrices that
could be analyzed using the Method and better assess the effect of
different matrices on solvent extraction performance, the Agency
collected samples from a variety of industrial facilities that were
different from those collected during Phase I of the study.
Analysis of each sample was performed in triplicate for each of the
three extraction solvents. Prior to the analysis of field samples, the
evaluating laboratory was required to demonstrate its ability to
generate acceptable accuracy and precision for each of the required
procedures by performing a series of initial precision and recovery
(IPR) analyses for determination of oil and grease and petroleum
hydrocarbons using Freon-113, n-hexane, and cyclohexane as extraction
solvents. IPR analyses involved extraction, concentration, and analysis
of a set of four 1-L aliquots of reagent water that had been spiked
with hexadecane and stearic acid. All IPR analyses included
modifications necessary to allow for differences in solvent densities
and other modifications necessary to apply Method 413.1 and Standard
Method 5520F to the alternative solvents, in order to evaluate any
effects that might result from the modified procedures.
An ongoing precision and recovery (OPR) analysis, the equivalent of
a single IPR sample, was required with each analytical batch for each
alternative solvent. An analytical batch consisted of a set of samples
extracted at the same time, to a maximum of ten samples.
In addition, a reagent water method blank was analyzed with each
IPR set and with each sample batch for each alternative solvent. These
reagent water blanks were run through the same extraction and analysis
procedure through which the samples were run. The analytical protocol
required that the concentration of oil and grease in method blanks not
exceed 5 mg/L and, if contamination above this level was detected in
any method blank, the laboratory was required to isolate the source of
contamination and reanalyze associated samples.
Multiple aliquots of each sample were collected in order to
accommodate the numerous analyses required. The multiple aliquots were
split from a homogenized sample and, to the extent practicable,
contained identical concentrations of oil and grease. Within each of
the three different solvent procedures and two modified methods (413.1
and 5520F), it was expected that the relative standard deviation (RSD)
of the triplicate measurements would be less than or equal to 10
percent for those results at or above 25 mg/L and less than or equal to
20 percent for those results less than 25 mg/L. The evaluating
laboratory was required to notify EPA if the triplicate results
exceeded these RSDs.
Addition of these QC requirements and data quality objectives to
the usual method protocol, and careful monitoring of the analytical
techniques ensured that reliable data were produced.
Alternative analytical techniques were also evaluated. These
techniques were performed voluntarily by manufacturers of various
devices on splits of samples collected as part of Phase II. EPA
supplied additional volumes of each sample collected during the Phase
II study to a number of vendors that tested alternative oil and grease
extraction and measurement techniques similar to those tested in the
Phase I study. These included solid phase extraction using cartridges
and disks, non-dispersive infrared spectroscopy, and immunoassay.
Evaluation of Phase II data led to the conclusion that the results
generated when using n-hexane and cyclohexane were statistically
equivalent to one another, but that these results were significantly
different from results generated when using Freon-113 as the extraction
solvent. These findings were consistent with the Phase I study
conclusion that, when all sample matrices are collectively considered,
none of the solvents that were evaluated was statistically equivalent
to Freon-113. Specifics of the study design, results, and conclusions
are included in the Report of EPA Efforts to Replace Freon for the
Determination of Oil and Grease and Total Petroleum Hydrocarbons: Phase
II, April 1995, that is included in the docket.
The decision of which alternative solvent was best suited for the
new method was therefore based on logistical analytical considerations,
of which the primary factor was the difference between the boiling
points of n-hexane (69 deg.C) and cyclohexane (81 deg.C). Based on
laboratory comments regarding the extensive amount of time required to
evaporate cyclohexane, n-hexane was determined to be a more suitable
replacement for Freon-113.
Evaluation of vendor data was limited to the SPE disk and column
extraction techniques with gravimetric determination, and demonstrated
that results from both of the SPE techniques were not statistically
equivalent to

[[Page 1733]]
results produced by either Freon-113 or n-hexane using separatory
funnel extraction and gravimetric determination.
Results from the non-dispersive infrared and immunoassay analyses
were not considered for this proposal because they represent completely
different determinative techniques. EPA is, however, planning to
further evaluate these techniques and consider other promising
procedures in subsequent studies.
Though written as a separatory funnel extraction procedure, Method
1664 allows the use of alternative extraction and concentration
techniques, such as SPE, under the performance-based option, provided
that these techniques produce results that meet the specifications in
Method 1664 when tested using reference standards and, when used for
compliance monitoring, produce results equivalent to results produced
by Method 1664 on the specific discharge to which they are to be
applied.
The Agency solicits additional comparative data and information on
SPE techniques and other alternative extraction and concentration
techniques, and on the proposal to allow these techniques under the
performance-based option in Method 1664. EPA is particularly interested
in comparative data produced from alternative techniques and separatory
funnel extraction with gravimetric determination when both techniques
are concurrently applied to a given wastewater discharge.
The final product of Phase II was Method 1664, which uses n-hexane
as the extraction solvent. Between April and September, 1994, the March
29, 1994 draft version of the Method was distributed extensively at
several conferences and workshops and in response to requests to EPA.
EPA encouraged reviewers to submit any questions, clarifications,
data, or issues for consideration in updating the Method for this
proposal. As part of the effort to collect information from interested
parties, a questionnaire pertaining to Phase II of the Freon
Replacement Study and the content of Method 1664 was distributed on May
4, 1994 at EPA's 17th Annual Conference on Analysis of Pollutants in
the Environment. EPA also collected information from studies performed
by industry representatives, including a report produced by the
American Petroleum Institute titled Method Development and Freon-113
Replacement in the Analysis of Oil and Grease in Petroleum Industry
Samples, and a presentation delivered by Dave Clampitt from the Uniform
& Textile Service Association at EPA's 17th Annual Conference on
Analysis of Pollutants in the Environment titled Impact of Detergents
on the Determination of Oil and Grease by Gravimetric and Infra-red
Analysis. Comments received as a result of these efforts were reviewed
and considered when revising Method 1664 to produce the April 1995
version being proposed today. These comments are included in the
docket.
The quality control acceptance criteria in Method 1664 were derived
from the Phase II results and the results from an interlaboratory study
conducted by 11 laboratories belonging to the Twin City Round Robin
Group. In addition, Method Detection Limit (MDL) studies were performed
to determine the MDL and minimum level (ML) specifications included in
the version of the Method being proposed today. Details of these
studies are included in the docket as part of the document titled
Report of the Method 1664 Validation Studies, April 1995.

B. N-Hexane as the Extraction Solvent

In the process of deciding upon the most suitable extraction
solvent for replacement of Freon-113, EPA considered the potential
effects of the new solvent on compliance monitoring, logistics, and
health and safety concerns. Of all the solvents evaluated in the Freon
Replacement Study, n-hexane was the most appropriate choice for the
following reasons: (1) It had been previously used as the extraction
solvent for permit compliance analysis of oil and grease and TPH prior
to the advent of Freon-113, (2) EPA Phase I and Phase II studies
indicated that n-hexane produces results that are as or more comparable
to Freon-113 results than other solvents (although no solvent produced
results exactly equivalent to Freon-113), and (3) the Phase II study
showed that there was no significant difference in results produced by
n-hexane and Freon-113 for the analysis of reagent water samples spiked
with reference standards. In addition, a comparison of the Phase I and
Phase II data suggests 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 currently
approved Freon methods that did not impose these thorough QC
requirements.
Once the solvent choices had been narrowed to cyclohexane and nhexane,
and the results of Phase II indicated that both solvents
produced equivalent results, the decision was based on more pragmatic
issues. Of concern was the neurotoxicity of n-hexane compared to
cyclohexane and the cost of the two solvents. EPA compared the
Occupational Safety and Health Administration (OSHA) permissible
exposure limits (PELs) for cyclohexane and n-hexane. This comparison
showed that n-hexane is only 1.7 times more toxic than cyclohexane and
that the time weighted average (TWA) for n-hexane is 300 ppm, compared
to 500 ppm for cyclohexane. TWA is defined as the average airborne
exposure that shall not be exceeded in any 8-hour work shift of a 40-
hour work week. Based on these figures, the toxicity of n-hexane is not
appreciably higher than that of cyclohexane and can be minimized by
implementing effective safety controls and procedures in the
occupational setting.
An examination of the relative costs of n-hexane and cyclohexane
revealed that cyclohexane costs approximately 17 percent more than nhexane
from the four suppliers surveyed.
Based on the solvent evaporation time issue presented in the
discussion on Phase II of the Freon Replacement Study and the cost
considerations detailed above, n-hexane was selected over cyclohexane
as the solvent to replace Freon-113.

III. Summary of Proposed Rule

A. Introduction

This proposed rule would allow the use of EPA Method 1664 for the
determination of ``oil and grease'' and ``total petroleum
hydrocarbons'', and would withdraw approval of EPA Method 413.1 and
Standard Method 5520B. Though on May 10, 1995, a global exemption for
laboratory and analytical essential uses of CFCs was granted for the
1996 and 1997 control periods (60 FR 24970), this proposed rule will
nonetheless provide for the elimination of the use of Freon-113 because
of the unacceptable inconsistencies that would be created by allowing
analytical methods employing two different solvents for determination
of oil and grease. The proposed replacement method, Method 1664: NHexane
Extractable Material (HEM) and Silica Gel Treated N-Hexane
Extractable Material (SGT-HEM) by Extraction and Gravimetry (Oil and
Grease and Total Petroleum Hydrocarbons), April 1995, is a gravimetric
procedure applicable to aqueous matrices for the determination of nhexane
extractable material and silica gel treated n-hexane extractable
material (oil and grease and total petroleum hydrocarbons,
respectively). The proposed method contains more

[[Page 1734]]
thorough QA/QC procedures than the Freon methods proposed for
withdrawal.
``Oil and Grease'' is a conventional pollutant defined in the Clean
Water Act and codified at 40 CFR 401.16. The term ``n-hexane
extractable material'' (HEM) reflects the fact that this method can be
applied to materials other than oils and greases. Similarly, the term
``silica gel treated n-hexane extractable material'' (SGT-HEM) reflects
that this method can be applied to materials other than aliphatic
petroleum hydrocarbons that are not adsorbed by silica gel.
Method 1664 is a performance-based method that allows alternative
extraction and concentration techniques, provided that equivalent
performance can be demonstrated using reference standards and by
complying with all performance specifications given in the Method.

B. Summary of Proposed Method 1664

For determination of n-hexane extractable material (HEM), samples
are acidified to pH <2 and serially extracted three times with 30-mL
portions of n-hexane in a separatory funnel. The extract is filtered
through sodium sulfate to remove residual water, and the solvent is
evaporated by heating with a steam or water bath. The HEM that remains
is weighed and the concentration calculated in mg/L.
For determination of silica gel treated n-hexane extractable
material (SGT-HEM), the HEM is redissolved in n-hexane, and silica gel
is added to remove adsorbable materials. The amount of silica gel added
is proportional to the amount of HEM. The solution is filtered to
remove the silica gel, the solvent is evaporated by heating, and the
SGT-HEM is weighed to produce the concentration in mg/L.

C. Method Quality Control

The quality control criteria incorporated into the Method exceeds
and improves upon that of the currently approved 40 CFR Part 136 oil
and grease methods, and is consistent with the 40 CFR 136 Appendix A
protocol for determination of organic analytes. Initial demonstrations
of laboratory capability are required and consist of (1) a method
detection limit (MDL) study to demonstrate that the laboratory is able
to achieve the MDL and ML specified in the Method, and (2) an initial
precision and recovery (IPR) test consisting of the analysis of four
spiked reagent water samples to demonstrate the laboratory's ability to
generate acceptable precision and accuracy.
An important component of these and other QC tests required in
Method 1664 is the use of hexadecane and stearic acid as the reference
standards for spiking. Hexadecane was chosen to simulate petroleum
hydrocarbons; stearic acid was chosen to simulate animal fats and
detergents, and serves to test the effects of the silica gel procedure.
The use of standards of known composition and purity, which are not a
requirement of the currently approved gravimetric methods for the
determination of oil and grease, allows for more accurate determination
of recovery and precision and minimizes variability that may be
introduced from spiking with substances such as Wesson oil, #2 fuel
oil, mineral oil, etc. that are comprised of unknown proportions of
substances.
Routine quality control consists of an initial two point
calibration of the analytical balance, and the following tests that
must accompany each analytical batch (the set of samples extracted at
the same time, to a maximum of 10 samples):
<bullet> Analysis of a matrix spike (MS) and matrix spike duplicate
(MSD) to demonstrate method accuracy and precision, and to monitor
matrix interferences. Hexadecane and stearic acid are the reference
standards used for spiking.
<bullet> Analysis of a laboratory blank to demonstrate freedom from
contamination.
<bullet> Verification of calibration of the analytical balance, to
demonstrate that measurements are in control.
<bullet> Analysis of an ongoing precision and recovery (OPR) sample
to demonstrate that the analysis system is in control and acceptable
precision and accuracy is being maintained with each analytical batch.
The OPR sample consists of reagent water spiked with hexadecane and
stearic acid. It is the equivalent of one of the IPR samples.
The laboratory is required to meet the acceptance criteria listed
in Method 1664 for these quality control tests and is encouraged to
monitor performance over time to identify and anticipate problems or
improvements to the procedure.
Aside from the use of a solvent other than Freon-113, the most
significant difference between Method 1664 and approved and existing
methods used for oil and grease and petroleum hydrocarbons
determinations is that Method 1664 contains an extensive QA/QC program
that allows the data user to evaluate the quality of the results. This
promotes a consistent, careful evaluation of the data generated that
increases the reliability of results produced by HEM and SGT-HEM
determinations, and provides a means for laboratories and data users to
monitor analytical performance, thereby providing a basis for sound,
defensible data.

D. Performance Based Approach

To allow for advances in technology and reductions in the cost of
analyses, Method 1664 is performance-based. Alternate extraction and
concentration procedures are permitted as long as the equivalency
procedures in the Method are followed and all QC acceptance criteria
are met. The equivalency procedures consist of performing the IPR test
using reference standards to demonstrate that the results produced with
the modified procedure meet the specifications in Method 1664. In
addition, if the detection limit will be affected by the modification,
performance of an MDL study is required to demonstrate that the
modified procedure can achieve an MDL less than or equal to the MDL in
the Method or, for those instances in which the regulatory compliance
level is greater than the Minimum Level in the Method, one-third the
regulatory compliance level, whichever is higher.
If the performance-based option is to be applied to analyses for
compliance monitoring, the discharger must demonstrate that the
modified method produces results equivalent to those produced by Method
1664 for each specific discharge. The reason that this additional
demonstration over and above the demonstration of equivalency with
reference standards is required is that the possibility exists that
Method 1664 and the modified method may produce equivalent results with
reference standards but not produce equivalent results when the
discharge is analyzed. Both Phase I and Phase II of the Freon
Replacement Study demonstrated that results produced by other solvents
are not equivalent to the results produced by Freon-113 when
comparative tests are performed on discharges. EPA is concerned that
the amount of material extracted from a discharge by a modified method
will not be equivalent to the amount of material extracted by Method
1664. If the amount of material extracted is less when the modified
method is used, the amount discharged could be greater before a
violation would occur. Similarly, if the amount of material extracted
is greater when the modified method is used, the amount discharged
would need to be less to prevent a violation. The requirement to verify
the equivalence of the modified method to Method 1664 assures that the
modified method and

[[Page 1735]]
Method 1664 exhibit equivalent performance on the specific discharge.
For those instances in which the results from the equivalence study
of field samples are below the Minimum Level, and the test of the
modified method is passed for spikes of reference standards into
reagent water, the modified method is deemed to be equivalent to this
method for determining HEM and/or SGT-HEM on that specific discharge.
This allowance is based on the reasoning that the level of material in
this discharge will be so low that it is unlikely a violation will ever
occur with this discharge and, consequently, small differences in the
amount measured with the modified method as compared to Method 1664
will be negligible.
The procedure required to demonstrate equivalency consists of the
following: (1) Two sets of four one-liter aliquots of a specific
discharge are collected for analysis--one set is analyzed according to
Method 1664--the other set is analyzed according to the modified
procedure, (2) the average percent recovery of HEM and/or SGT-HEM is
calculated for each set of four analyses, and (3) the average percent
recovery using the modified procedure must be 79-114 percent of the
average percent recovery produced by Method 1664 for HEM and 66-114
percent of the average percent recovery produced by Method 1664 for
SGT-HEM. Unless these criteria are met, the modified procedure cannot
be used for compliance monitoring purposes.
Whether or not the modified procedure is applied to compliance
monitoring, all modifications to the Method must be thoroughly
documented and the documentation must be maintained in the format
specified in Method 1664.

IV. Method Validation and Precision and Recovery of the Proposed Test
Method

The version of Method 1664 being proposed today is the product of
revisions to the March 29, 1994 draft, and the October 1994 and January
1995 versions, and reflects consideration of numerous peer review
comments, survey results, data from industry studies, results from an
interlaboratory method validation study, and results from several EPA
single-laboratory method detection limit (MDL) studies.

A. Precision and Recovery Studies

The interlaboratory method validation study conducted by EPA
consisted of tests of initial precision and recovery (IPR) and ongoing
precision and recovery (OPR) in twelve different analytical testing
laboratories. Data produced in this study were used to derive the QC
acceptance criteria for precision and recovery that are specified in
Table 1 of Method 1664. Details of the analyses and results are
described in a document titled Report of the Method 1664 Validation
Studies, April 1995.
One of the twelve laboratories participating in the validation
study performed the QC analyses, which included one set of IPR analyses
and 30 OPR analyses, as part of the n-hexane, cyclohexane, and Freon-
113 comparisons for Phase II of the Freon Replacement Study. Since many
of the techniques incorporated into Method 1664 evolved as this
evaluating laboratory performed analyses under Phase II of the Freon
Replacement Study, some of the work was developmental in nature. For
example, the decision to use hexadecane and stearic acid as spiking
standards required determination of an appropriate concentration as
well as an appropriate solvent for the stock solution.
Another issue was the applicability of the silica gel extraction
procedure to HEM concentrations in excess of 100 mg/L. The adsorptive
capacity of silica gel needed to be studied in order to determine the
amount of silica gel required to adsorb increasing concentrations of
HEM. In addition, it was necessary to determine an appropriate cutoff
for the maximum amount of silica gel that realistically could be used.
Through a series of tests, it was determined that if more than 30 g of
silica gel is used, the potential for contamination from substances in
the silica gel increases.
Analysis of IPRs prior to sample analysis and continuing evaluation
of the analytical system through OPR analyses were necessary to
evaluate the potential effects of all procedural changes implemented as
a result of this developmental work.
Results from the evaluating laboratory's analysis of real world
samples supports the Method 1664 criteria derived from the method
validation data. Because each field sample was analyzed in triplicate,
the standard deviation of the replicate values could be derived. The
mean relative standard deviation (RSD) across all analyses was 11.5
percent, thereby demonstrating the precision of Method 1664 on real
world sample matrices.
The other eleven laboratories involved in method validation,
working cooperatively as part of the Twin City Round Robin (TCRR)
Group, performed IPR and OPR analyses for the determination of HEM by
Method 1664. In addition to the QC analyses, this study consisted of
the analysis of two sets of samples, one from a petroleum source and
the other from a nonpetroleum source, in triplicate, for HEM. The mean
RSD of the results across all laboratories and all samples was 9.5
percent, further demonstrating that Method 1664 is capable of producing
precise results on real world samples. Results and evaluation of the
TCRR study, including field sample analyses, are presented in the
document titled Report of the Method 1664 Validation Studies, April
1995.
TCRR study participants submitted comments on the method, most of
which focused on difficulties related to extracts containing excessive
amounts of water and the longer time required for the evaporation of nhexane.
These issues have been addressed in the revision of Method 1664
being proposed today, the former by recommending more careful
separation of the aqueous and solvent phases to avoid carryover of the
water into the extract and that more sodium sulfate be used in the
filtering process, and the latter by allowing the use of either a water
bath or steam bath set at a temperature that results in evaporation of
the solvent within 30 minutes.
Most laboratories in the interlaboratory study did not encounter
difficulties with the analysis of IPR and OPR samples and were able to
achieve acceptable recoveries of hexadecane and stearic acid.
Statistical evaluation of the results from all twelve laboratories
produced few outliers, indicating that Method 1664 is a reproducible
procedure sufficiently reliable to be used by a variety of
laboratories.

B. Development of Quality Control Acceptance Criteria

As stated above, data from the TCRR interlaboratory study were
combined with data from EPA's data gathering in Phase II to produce
performance specifications in the form of quality control (QC)
acceptance criteria for Method 1664. The development of these criteria
are described in the Report of the Method 1664 Validation Studies,
April 1995, included in the docket. Criteria were developed for initial
precision and recovery (IPR), ongoing precision and recovery (OPR), and
recovery of hexadecane and stearic acid spiked into samples (matrix
spikes) for both HEM and SGT-HEM. For HEM, the IPR and OPR acceptance
criteria were constructed using analysis of variance (ANOVA)
statistics. The criteria for recovery of a matrix spike (MS) and for
the relative percent difference between an MS and a matrix spike
duplicate

[[Page 1736]]
(MSD) were transferred from the IPR and OPR criteria, since neither the
TCRR study or EPA's data gathering efforts required the spiking of
field samples. EPA believes that this transfer is acceptable because
the determinative technique in Method 1664 is gravimetry, which is not
susceptible to interferences, and because the treated effluent to which
Method 1664 is to be applied in monitoring is nearly identical to the
reagent water used in the IPR and OPR tests. EPA used a similar
transfer of data for development of specifications for acceptance
criteria in the organic methods promulgated at 40 CFR Part 136,
Appendix A.
For SGT-HEM, EPA received results from only two laboratories. EPA
used these data to construct preliminary acceptance criteria for SGTHEM
and widened these preliminary criteria to those of HEM in those
instances in which the calculated SGT-HEM criteria were more stringent
than those for HEM. The acceptance criteria were widened based on the
knowledge that the determination of SGT-HEM follows the determination
of HEM in Method 1664, and therefore the results for SGT-HEM is likely
to be at least as variable as results for HEM.
EPA solicits data on the variability of the determination of HEM
and SGT-HEM, particularly data from interlaboratory studies using
either the March 29, 1994 version of Method 1664 that was distributed
at various conferences, the October 1994 or January 1995 versions of
Method 1664, or the April 1995 version that is cited in today's
proposed rule and which is included in the docket.

C. Method Detection Limit Studies

To date, five single-laboratory method detection limit (MDL)
studies have been performed as part of the effort to determine MDLs and
MLs for HEM and SGT-HEM. Results of these studies are detailed in the
document titled Report of the Method 1664 Validation Studies, April
1995. The MDL is defined as the minimum concentration of a substance
that can be measured and reported with 99 percent confidence that the
analyte concentration is greater than zero. To determine the MDL, the
laboratories were required to follow the procedure in Appendix B to 40
CFR Part 136. This procedure consists of the analysis of seven aliquots
of reagent water that are spiked with the analyte(s) of interest. For
EPA's MDL studies, the hexadecane and stearic acid specified in the
quality control tests in Method 1664 were used. Spike levels were in
the range of one to five times the estimated detection limit. The MDL
is calculated by multiplying the standard deviation of the seven
replicate analyses by the Student's t value for (n-1) degrees of
freedom, where n equals the number of replicates. The Student's t value
for seven replicates is 3.143.
The Minimum Level is defined as the level at which the entire
analytical system produces a recognizable signal and an acceptable
calibration point, and is determined by multiplying the MDL by 3.18 and
rounding the resulting value to the number nearest to (1, 2, or 5) x
10n, where n is an integer. The value ``3.18'' represents the
ratio between the Student's t multiplier used to determine the MDL
(3.143) and the 10 times multiplier used in the American Chemical
Society (ACS) Limit of Quantitation (LOQ) (i.e., 10 <divide> 3.143 =
3.18). For example, if the calculated MDL is 1.7, the ML will be equal
to 1.7 times 3.18, which equals 5.1. Rounding to the number nearest to
(1, 2, or 5) x 10n establishes the ML at 5.0.
The first MDL study was performed in a commercial laboratory by an
analyst at the Ph.D. level who has more than 20 years of experience in
the determination of oil and grease and TPH. This study yielded an MDL
of 0.91 mg/L and a resultant ML of 2 mg/L for HEM and an MDL of 1.6 mg/
L and a resultant ML of 5 mg/L for SGT-HEM.
Based on the disparity between the results obtained by this
laboratory and the lower limit of the range in Method 413.1, it was
decided that a second MDL study should be conducted in another
commercial laboratory to verify the values obtained in the first study.
The second MDL study was also performed by a laboratory experienced
in the determination of oil and grease and TPH, though the analysts
performing the study were not at the Ph.D. level. In order to move
expeditiously, the laboratory was required to perform the second MDL
study within 24 hours. An MDL of 5.4 mg/L and an ML of 20 mg/L for HEM,
and an MDL of 2.6 mg/L and an ML of 10 mg/L for SGT-HEM was determined
in the second MDL study.
The second laboratory was contacted to determine if they
encountered difficulties in performing the study. They stated that the
results were the best that could be obtained under the imposed 24 hour
turn-around time constraint, and that they believed they could achieve
lower MDLs given more time. Based on these circumstances, the Agency
decided that the MDLs to be included in the October version of Method
1664 should be those representing the better performing laboratory.
Therefore, the MDL and associated ML values from the original Method
1664 MDL study were incorporated into the October 1994 revision of the
Method.
The high results produced in the second MDL study brought into
question the reasonableness and effect of requiring a 24-hour
turnaround. As a result, the second laboratory performed another MDL
study (MDL study #3), this time without the turnaround constraint, and
with the analytical objective to confirm the MDLs/MLs that had been
obtained in the first MDL study. An MDL of 2.4 mg/L and an associated
ML of 10 mg/L for HEM, and an MDL of 1.7 mg/L and an associated ML of 5
mg/L for SGT-HEM were obtained from this third MDL study. Although
closer to the MDL and ML for HEM obtained in the first MDL study, the
ML of 10 mg/L for HEM is still above the equivalent level in Method
413.1, and the result for SGT-HEM, the more complex procedure, is still
less than the result for HEM.
From these results, the Agency concluded that the MDLs/MLs for HEM
and SGT-HEM produced in the first MDL study are self-consistent,
whereas the results produced in the second and third MDL studies are
not. Therefore, the MDL and ML limits specified in the January 1995
version of the Method were those from the first MDL study.
The Agency still needed to address the issue that the HEM MDL
values in both the October 1994 and the January 1995 versions of Method
1664 had not been verified with follow-up MDL studies. In contrast, a
comparison of SGT-HEM results shows that the MDL/ML for SGT-HEM from
the third MDL study supports the first MDL study results for SGT-HEM.
(Both the first and third MDL studies produced an ML of 5 mg/L for SGTHEM.)

To verify the HEM MDL and ML values specified in the October 1994
and January 1995 versions of Method 1664, which were the results
obtained in MDL study #1, the laboratory that performed this MDL study
conducted another study (MDL study #4). As with MDL study #1, the same
Ph.D. level chemist with extensive analytical experience performed the
analyses. Because the spike level in MDL study #1 was greater than five
times the resulting MDL, the spike level was lowered to 5 mg/L. An MDL
of 0.88 mg/L, with a resulting ML of 2 mg/L was obtained, thereby
supporting the original MDL results.
In response to comments received from laboratories and other
interested parties regarding the difficulties encountered when
attempting to achieve the HEM MDL of 0.91 mg/L specified in the October
1994 and January 1995 versions of Method 1664,

[[Page 1737]]
and because most technicians performing HEM analysis for commercial
laboratories will not have the experience or qualifications of the
Ph.D. level chemist who performed MDL studies 1 and 4, an analyst with
a bachelor's degree and one month's laboratory experience performed
another HEM MDL study at this laboratory. The results of MDL study #5
were an HEM MDL of 1.4 mg/L and a resulting ML of 5 mg/L.
EPA has concluded that the MDL appropriate for Method 1664 should
be representative of a better performing laboratory. However, to
realistically address the qualifications of the laboratory personnel
most likely to perform this procedure, the MDL should reflect the
results obtained when using qualified, but not Ph.D. level, personnel.
Therefore, the HEM MDL specified in the April 1995 version of Method
1664 (the version being proposed) is 1.4 mg/L and the HEM ML is 5 mg/L.
Unchanged from the January 1995 version of Method 1664, the SGT-HEM MDL
is 1.6 mg/L and the SGT-HEM ML is 5 mg/L.
EPA solicits comment on the appropriateness of these MDLs and data
from other MDL studies conducted with the goal of achieving an MDL of 1
mg/L or less for HEM and SGT-HEM.

V. Withdrawal of Currently Approved Methods

The Clean Air Act Amendments of 1990 (CAAA) established schedules
for phasing out the production and importation of CFCs in the U.S.
Pursuant to section 606, production of most class I substances,
including Freon, is phased-out as of January 1, 1996, except for a few
exemptions for essential uses. Existing supplies may be used after that
date, but the substances will become increasingly scarce and costly
over time. On May 10, 1995, a global exemption for laboratory and
essential analytical uses of CFCs was granted for the 1996 and 1997
control periods (60 FR 24970). This exemption explicitly allows for the
production of CFCs for laboratory use through December 31, 1997.
Therefore, it would be possible to allow continued use of the currently
approved analytical methods that employ CFCs along with the use of
Method 1664.
EPA has considered allowing continued use of the currently approved
methods, but believes that unacceptable conflicts would be created by
allowing the simultaneous use of oil and grease methods that employ
different extraction solvents. As is detailed above, EPA's Freon
Replacement Studies indicated that no solvent produces results
sufficiently equivalent to the results produced by Freon-113. By
allowing two or more methods that employ different solvents, the
possibility exists that a regulatory authority and a discharger could
produce different results for the same analyte in the same sample.
Indeed, the same analyst testing the same sample could produce
unacceptably different results using the different methods. If one of
these results showed a permit violation and the other did not, an
unfair conflict would result.
As is also detailed above, Method 1664 contains extensive quality
control procedures to assure that precise and accurate results are
produced. If use of the currently approved methods is continued, the
possibility also exists that analytical results could indicate a permit
violation due to the greater variability of results produced by these
methods when compared to the proposed Method 1664. For example, if the
permit limit is 20 mg/L and the true concentration of oil and grease in
the discharge is slightly less than this limit, Method 1664 is more
likely to produce a result closer to the true value than the currently
approved methods because of the improved precision of the Method.
The conflict between results obtained using the existing approved
methods and results obtained using the proposed Method 1664 arises
because oil and grease is a ``method-defined'' parameter. Much like
biochemical oxygen demand measured over five days (``BOD<INF>5''), and
total suspended solids (``TSS''), which measures the amount of nonfilterable
material suspended in water, the quantification of oil and
grease depends on the procedures used to measure the parameter in the
first place. The analytical result is dependent on how the measurement
is conducted. In the case of BOD<INF>5, the sample pH, the seed
quality, the incubation time and temperature, and other factors define
how much BOD occurs. In the case of TSS, the sample homogeneity, the
filter type and pore size, the drying time and temperature, and other
factors determine the amount of solids that will be measured. In the
specific case of oil and grease, one portion of the test sample
preparation procedure, the addition of a specific solvent, defines how
much ``oil and grease'' will be extracted. The oil and grease parameter
is that material which is extracted by the solvent and not lost during
solvent drying or evaporation.
Given these concerns, and to avoid other potential conflicts, EPA
is proposing to withdraw approval of the use of methods for oil and
grease determination that are currently promulgated at 40 CFR Part 136.
In an effort to provide for the use and depletion of existing
laboratory stocks of Freon-113, EPA plans to implement the withdrawal
of the existing Freon methods no sooner than six months after the final
rule is published in the Federal Register. In this scenario, Freon-113
and the currently approved methods would continue to be used until the
implementation date. N-hexane and Method 1664 would be required on that
date and thereafter. EPA seeks comment on the desirability of this
scenario, alternate scenarios, and whether the 6-month period is
sufficient or, if insufficient, the length of the desired period. EPA
also seeks comment as to whether the 6-month period is too long, in
that persons and organizations affected by this rule may desire to
switch to n-hexane sooner to reduce the costs associated with the
purchase of Freon-113. When submitting comments on this issue, please
indicate the amount of Freon-113 being used by your organization for
oil and grease determinations using the currently approved 40 CFR Part
136 methods so that EPA can assess the number of parties affected and
the extent of the effect.

VI. Regulatory Requirements

A. Regulatory Impact Analysis

Executive Order 12866 requires that regulatory agencies prepare an
analysis of the regulatory impact of major rules. Major rules are
defined as those likely to result in: (1) An annual cost to the economy
of $100 million or more; or (2) a major increase in costs or prices for
consumers or individual industries; or (3) significant adverse effects
on competition, investment, innovation, or international trade. This
regulation is not a major regulation for the reasons discussed below.
The impact of this proposed regulation will be far less than $100
million annually. Laboratories are switching to CFC substitutes (or
substitute methods) as CFCs become more costly due to restriction in
supply and due to the excise tax that, as a result of the 1989 and 1990
Budget Reconciliation Acts, is imposed on all ozone-depleting chemicals
listed in the Montreal Protocol and the 1990 CAAA. Thus, the true cost
of this regulation is the difference in expense of switching to CFC
substitutes now as opposed to later. The Agency believes that these
increased transitional costs will be minimal for the following reasons:
First, laboratory testing is a very small part of Freon-113
consumption (less

[[Page 1738]]
than 1 percent) and the testing required by EPA is only a fraction of
this total. EPA estimates that the total market for Freon-113 for
laboratory use is less than $2 million annually.
Second, this rule is not likely to cause a major increase in costs
or prices for individuals or consumers. 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. However, the price for n-hexane is actually
cheaper per pound than the CFCs and this difference may increase as CFC
production is reduced and supply becomes more limited.
Third, this regulation is unlikely to cause significant adverse
effects on competition, investment, innovation, or international trade.
As noted above, laboratory use of these products is estimated to be
much less than 1 percent of the total market for these products.
Further, in some cases this proposed rule and notice would result in a
switch back to procedures commonly used in the 1970s, which did not
have a significant impact on competition, investment, or trade at that
time.
On March 9, 1995, this proposal was granted a waiver from review by
the Office of Management and Budget.

B. Unfunded Mandates

Under Section 202 of the Unfunded Mandates Reform Act of 1995,
signed into law on March 22, 1995, EPA must prepare a statement to
accompany any rule where the estimated costs to State, local, or tribal
governments, or to the private sector, will be $100 million or more in
any one year. Under Section 205, EPA must select the most costeffective
and least burdensome alternative that achieves the objective
of the rule and is consistent with statutory requirements. Section 203
requires EPA to establish a plan for informing and advising any small
governments that may be significantly impacted by the rule.
EPA estimates that the costs to State, local, or tribal
governments, or to the private sector, from this rule will be less than
$100 million. This rulemaking should have minimal impact on the current
regulatory burden imposed on permittees because the rulemaking will
simply replace an existing test procedure with a new procedure. EPA has
determined that an unfunded mandates statement is therefore
unnecessary. Similarly, the method in today's rule does not establish
any regulatory requirements that might significantly or uniquely affect
small governments.

C. Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility Act, 5 U.S.C. 601, whenever
an agency is required to publish a notice of rulemaking for any
proposed or final rule, it must prepare and make available for public
comment a Regulatory Flexibility Analysis that describes the effect of
the rule on small entities (i.e., small businesses, small
organizations, and small governmental jurisdictions). This analysis is
unnecessary if the Agency's Administrator certifies that the rule will
not have a significant economic effect on a substantial number of small
entities.
This proposed rule will not have a significant economic impact on a
substantial number of small facilities. This regulation simply approves
an analytical technique to be available for use by all laboratories.

D. Paperwork Reduction Act

This rule contains no requests for information and is, therefore,
exempt from the requirements of the Paperwork Reduction Act, 44 U.S.C.
3501 et seq.

VII. Materials Proposed for Incorporation by Reference Into 40 CFR
Part 136

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), April
1995, Document No. EPA-821-B-94-004b, available from the EPA Water
Resource Center, Mail Code RC-4100, 401 M Street, S.W., Washington,
D.C. 20460, phone: 202/260-7786 or 202/260-2814.

VIII. Request for Comments

EPA requests public analysis, comments, and information on the
replacement of Freon-113 with n-hexane, the utility of Method 1664 for
monitoring, the QC acceptance criteria in Method 1664, the MDL and ML
levels, the performance-based option criteria, and the 6-month
implementation scenario.

List of Subjects in 40 CFR Part 136

Environmental protection, Reporting and recordkeeping requirements,
Water pollution control, Incorporation by reference.

Dated: December 12, 1995.
Carol M. Browner,
Administrator.

In consideration of the preceding, USEPA proposes to amend 40 CFR
Part 136 as follows:

PART 136--[AMENDED]

The authority citation of 40 CFR Part 136 continues to read as
follows:

Authority: Secs. 301, 304(h), 307, and 501(a) Pub. L. 95-217,
Stat. 1566, et seq. (33 U.S.C. 1251, et seq.) (The Federal Water
Pollution Control Act Amendments of 1972 as amended by the Clean
Water Act of 1977 and the Water Quality Act of 1987), 33 U.S.C. 1314
and 1361; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 92-
217; Stat. 7, Pub. L. 100-4 (The ``Act'').

2. In Sec. 136.3(a), Table 1B.-List of Approved Inorganic Test
Procedures, is proposed to be amended by revising entry 41. Oil and
grease-Total recoverable; by adding an entry for petroleum
hydrocarbons, total recoverable; and by adding a note to Table 1B to
reference Method 1664 to read as follows:

Sec. 136.3 Identification of test procedures.

* * * *

Table 1B.--List of Approved Inorganic Test Procedures

Reference (Method No. or page)
--------------------------------------------
Std.
Parameter, units and methods EPA 1, methods
35 18th ASTM USGS2 Other
Ed.

*
41. Oil and grease--Total recoverable, mg/L; Gravimetric
(extraction)...................................................... XX1664
----. Petroleum hydrocarbons--Total recoverable; mg/L; Gravimetric
(extraction)...................................................... XX1664

[[Page 1739]]

XX Method 1664: N-Hexane Extractable Material (HEM) and Silica Gel Treated N-Hexane Extractable Material (SGTHEM)
by Extraction and Gravimetry (Oil and Grease and Total Petroleum Hydrocarbons), April 1995, Document No.
EPA-821-B-94-004b, can be obtained from the EPA Water Resource Center, Mail Code RC-4100, 401 M Street, S.W.,

Washington, D.C. 20460.

* * * *
In Sec. 136.3(e), Table II--Required Containers, Preservation
Techniques, and Holding Times, is proposed to be amended by adding an
entry for petroleum hydrocarbons to read as follows:

Sec. 136.3 Identification of test procedures.

* * * *

Table II.--Required Containers, Preservation Techniques, and Holding Times

Maximum
Parameter Container Preservation 2,3 holding
1 time 4

*
(Add the following entry.)

-- --. Petroleum hydrocarbons................... G Cool to 4 deg. C, H<INF>2SO<INF>4 or HCL to pH<2. 28 days.

[FR Doc. 96-877 Filed 1-22-96; 8:45 am]
BILLING CODE 6560-50-P

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