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

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.

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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.

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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 (EMSL-

Ci). 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.

1. 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/non-

dispersive 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 n-

hexane and because of its lower neurotoxicity when compared to n-

hexane.

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

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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 n-

hexane, 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 n-

hexane 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: 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, is a 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 total petroleum hydrocarbons,

respectively). The proposed method contains more

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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 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.

Analysis of a laboratory blank to demonstrate freedom from

contamination.

Verification of calibration of the analytical balance, to

demonstrate that measurements are in control.

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 n-

hexane. 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 SGT-

HEM 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 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 SGT-

HEM.)

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 (``BOD5''), and

total suspended solids (``TSS''), which measures the amount of non-

filterable 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 BOD5, 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 cost-

effective 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

1. 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]

1. 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 (SGT-

HEM) 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.

* * * * *

3. 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, H2SO4 or HCL to pH<2. 28 days.

* * * * * *

*

----------------------------------------------------------------------------------------------------------------

[FR Doc. 96-877 Filed 1-22-96; 8:45 am]

BILLING CODE 6560-50-P