Blanks—Rinse glassware and centrifuge tubes used in the method with 30
mL of methylene chloride, remove a 0.5-g aliquot of the solvent, spike
it with the 500 µL of the internal standard solution (Section   REF
_Ref239041418 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ) and analyze a 1-µL
aliquot of the blank sample using the procedure in Section   REF
_Ref239042689 \r \h  \* MERGEFORMAT  6.11 . Compute results per Section
 REF _Ref239042712 \r \h  \* MERGEFORMAT  6.12 .

Matrix spike sample—Prepare a matrix spike sample according to
procedure outlined in Section   REF _Ref239042200 \r \h  \* MERGEFORMAT
<IP_ADDRESS> . Analyze the sample and calculate the concentration (% oil) in
the drilling fluid and % recovery of oil from the spiked drilling fluid
using the methods described in Sections   REF _Ref239042771 \r \h  \*
MERGEFORMAT  6.11  and   REF _Ref239042782 \r \h  \* MERGEFORMAT  6.12 .

Duplicates—A duplicate field sample shall be prepared and analyzed
according to Section   REF _Ref239042801 \r \h  \* MERGEFORMAT  6.11 .
The relative percent difference (RPD) of the calculated concentrations
shall be less than 15%.

Analyze each of the duplicates per the procedure in Section   REF
_Ref239043240 \r \h  \* MERGEFORMAT  6.11  and compute the results per
Section   REF _Ref239043270 \r \h  \* MERGEFORMAT  6.12 .

ng equation:

 	[  STYLEREF 1 \s  6 -  SEQ Equation \* ARABIC \s 1  1 ]

Where:

D1	= 	Concentration of crude oil in the sample; and

D2	= 	Concentration of crude oil in the duplicate sample.

If the RPD criteria are not met, the analytical system shall be judged
to be out of control, and the problem must be immediately identified and
corrected, and the sample batch re-analyzed.

A clean NAF sample shall be prepared and analyzed according to Section
6.11. Ultimately the oil-equivalent concentration from the TIC or EIP
signal measured in the clean NAF sample shall be subtracted from the
corresponding authentic field samples in order to calculate the true
contaminant concentration (% oil) in the field samples (see Section
REF _Ref239043745 \r \h  \* MERGEFORMAT  6.12 ).

The specifications contained in this method can be met if the apparatus
used is calibrated properly, and maintained in a calibrated state. The
standards used for initial precision and recovery (Section   REF
_Ref239038963 \r \h  \* MERGEFORMAT  6.9.2  ) and ongoing precision and
recovery (Section   REF _Ref239041577 \r \h  \* MERGEFORMAT  6.11.6 )
shall be identical, so that the most precise results will be obtained.
The GC/MS instrument will provide the most reproducible results if
dedicated to the setting and conditions required for the analyses given
in this method.

Depending on specific program requirements, field replicates and field
spikes of crude oil into samples may be required when this method is
used to assess the precision and accuracy of the sampling and sample
transporting techniques.

Calibration

Establish gas chromatographic/mass spectrometer operating conditions
given in   REF _Ref238292704 \h  Table 6-1 . Perform the GC/MS system
hardware-tune as outlined by the manufacture. The gas chromatograph
shall be calibrated using the internal standard technique.

Note: Because each GC is slightly different, it may be necessary to
adjust the operating conditions (carrier gas flow rate and column
temperature and temperature program) slightly until the retention times
in   REF _Ref238292711 \h  Table 6-2  are met.

Table   STYLEREF 1 \s  6 -  SEQ Table \* ARABIC \s 1  1 . Gas
Chromatograph/Mass Spectrometer (GC/MS) Operation Conditions

Parameter	Setting

Injection port	280°C

Transfer line	280°C

Detector	280°C

Initial Temperature	50°C

Initial Time	5 minutes

Ramp	50 to 300°C @ 5°C per minute

Final Temperature	300°C

Final Hold	20 minutes or until all peaks have eluted

Carrier Gas	Helium

Flow rate	As required for standard operation

Split ratio	As required to meet performance criteria (~1:100)

Mass range	35 to 600 amu.

Table   STYLEREF 1 \s  6 -  SEQ Table \* ARABIC \s 1  2 . Approximate
Retention Time for Compounds

Compound	Approximate retention time (minutes)

Toluene	5.6

Octane, n−C8	7.2

Ethylbenzene	10.3

1,2,4-Trimethylbenzene	16.0

Decane, −C10	16.1

TCB (Internal Standard)	21.3

Dodecane, −C12	22.9

1-Methylnaphthalene	26.7

1-Tetradecene	28.4

Tetradecane, −C14	28.7

1,3-Dimethylnaphthalene	29.7

Internal standard calibration procedure—1,3,5-trichlorobenzene (TCB)
has been shown to be free of interferences from diesel and crude oils
and is a suitable internal standard.

The system performance test mix standards prepared in Section   REF
_Ref239045057 \r \h  \* MERGEFORMAT  <IP_ADDRESS>  shall be used to establish
retention times and establish qualitative detection limits.

Spike a 500-mL aliquot of the 1.25 mg/mL SPTM standard with 500 µL of
the TCB internal standard solution.

Inject 1.0 µL of this spiked SPTM standard onto the GC/MS in order to
demonstrate proper retention times. For the GC/MS used in the
development of this method the ten compounds in the mixture had typical
retention times shown in   REF _Ref238292711 \h  Table 6-2  above.
Extracted ion scans for m/z 91 and 105 showed a maximum abundance of
400,000.

Spike a 500-mL aliquot of the 0.125 mg/mL SPTM standard with 500 µL of
the TCB internal standard solution.

Inject 1.0 µL of this spiked SPTM standard onto the GC/MS to monitor
detectable levels. For the GC/MS used in the development of this test,
all ten compounds showed a minimum peak height of three times signal to
noise. Extracted ion scans for m/z 91 and 105 showed a maximum abundance
of 40,000.

GC/MS crude oil/drilling fluid calibration—There are two methods of
quantification: Total Area Integration (C8–C13) and EIP Area
Integration using m/z's 91 and 105. The Total Area Integration method
should be used as the primary technique for quantifying crude oil in
NAFs. The EIP Area Integration method should be used as a confirmatory
technique for NAFs. However, the EIP Area Integration method shall be
used as the primary method for quantifying oil in enhanced mineral oil
(EMO) based drilling fluid. Inject 1.0 µL of each of the four crude
oil/drilling fluid calibration standards prepared in Section   REF
_Ref239045212 \r \h  \* MERGEFORMAT  <IP_ADDRESS>  into the GC/MS. The
internal standard should elute approximately 21–22 minutes after
injection. For the GC/MS used in the development of this method, the
internal standard peak was (35 to 40)% of full scale at an abundance of
about 3.5e+07.

Total Area Integration Method—For each of the four calibration
standards obtain the following: Using a straight baseline integration
technique, obtain the total ion chromatogram (TIC) area from C8 to C13.
Obtain the TIC area of the internal standard (TCB). Subtract the TCB
area from the C8–C13area to obtain the true C8–C13 area. Using the
C8–C13 and TCB areas, and known internal standard concentration,
generate a linear regression calibration using the internal standard
method. The r2 value for the linear regression curve shall be greater
than or equal to 0.998. Some synthetic fluids might have peaks that
elute in the window and would interfere with the analysis. In this case
the integration window can be shifted to other areas of scan where there
are no interfering peaks from the synthetic base fluid.

EIP Area Integration—For each of the four calibration standards
generate Extracted Ion Profiles (EIPs) for m/z 91 and 105. Using
straight baseline integration techniques, obtain the following EIP
areas:

For m/z 91 integrate the area under the curve from approximately 9
minutes to 21–22 minutes, just prior to but not including the internal
standard.

For m/z 105 integrate the area under the curve from approximately 10.5
minutes to 26.5 minutes.

Obtain the internal standard area from the TCB in each of the four
calibration standards, using m/z 180.

Using the EIP areas for TCB, m/z 91 and m/z105, and the known
concentration of internal standard, generate linear regression
calibration curves for the target ions 91 and 105 using the internal
standard method. The r2 value for each of the EIP linear regression
curves shall be greater than or equal to 0.998.

Some base fluids might produce a background level that would show up on
the extracted ion profiles, but there should not be any real peaks
(signal to noise ratio of 1:3) from the clean base fluids.

Procedure

Sample Preparation

Mix the authentic field sample (drilling fluid) well. Transfer (weigh) a
30-g aliquot of the sample to a labeled centrifuge tube.

Centrifuge the aliquot for a minimum of 15 min at approximately 15,000
rpm, in order to obtain a solids free supernate.

Weigh 0.5 g of the supernate directly into a tared and appropriately
labeled GC straight vial.

Spike the 0.5-g supernate with 500 µL of the 0.01g/mL
1,3,5-trichlorobenzene internal standard solution (see Section   REF
_Ref239041418 \r \h  \* MERGEFORMAT  <IP_ADDRESS>  ), cap with a Teflon lined
crimp cap, and vortex for ca. 10 sec.

The sample is ready for GC/MS analysis.

Gas Chromatography

  REF _Ref238292704 \h  Table 6-1  summarizes the recommended operating
conditions for the GC/MS. Retention times for the n-alkanes obtained
under these conditions are given in   REF _Ref238292711 \h  Table 6-2 .
Other columns, chromatographic conditions, or detectors may be used if
initial precision and accuracy requirements (Section   REF _Ref239038963
\r \h  \* MERGEFORMAT  6.9.2  ) are met. The system shall be calibrated
according to the procedures outlined in Section   REF _Ref239162170 \r
\h  \* MERGEFORMAT  6.10 , and verified every 12 hours according to
Section   REF _Ref239041577 \r \h  \* MERGEFORMAT  6.11.6 .

Samples shall be prepared (extracted) in a batch of no more than 20
samples. The batch shall consist of 20 authentic samples, 1 blank
(Section    REF _Ref239042114 \r \h  \* MERGEFORMAT  6.9.3 ), 1 matrix
spike sample (Section   REF _Ref239042138 \r \h  6.9.4 ), and 1
duplicate field sample (  REF _Ref239042160 \r \h  6.9.5 ), and a
prepared sample of the corresponding clean NAF used in the drilling
process.

An analytical sequence shall be analyzed on the GC/MS where the 3 SPTM
standards (Section   REF _Ref239045057 \r \h  \* MERGEFORMAT  <IP_ADDRESS> )
containing internal standard are analyzed first, followed by analysis of
the four GC/MS crude oil/drilling fluid calibration standards (Section
REF _Ref239045212 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ), analysis of the
blank, matrix spike sample, the duplicate sample, the clean NAF sample,
followed by the authentic samples.

Samples requiring dilution due to excessive signal shall be diluted
using methylene chloride.

Inject 1.0 µL of the test sample or standard into the GC, using the
conditions in   REF _Ref238292704 \h  Table 6-1 .

Begin data collection and the temperature program at the time of
injection.

Obtain a TIC and EIP fingerprint scans of the sample (  REF
_Ref238292734 \h  Table 6-3 ).

If the area of the C8 to C13 peaks exceeds the calibration range of the
system, dilute a fresh aliquot of the test sample weighing 0.50-g and
re-analyze.

Determine the C8 to C13 TIC area, the TCB internal standard area, and
the areas for the m/z 91 and 105 EIPs. These shall be used in the
calculation of oil concentration in the samples (see Section   REF
_Ref239045581 \r \h  \* MERGEFORMAT  6.12 ).

Table   STYLEREF 1 \s  6 -  SEQ Table \* ARABIC \s 1  3 . Recommended
Ion Mass Numbers

Selected Ion Mass Numbers	Corresponding Aromatic Compounds	Typical
Retention Time (Minutes)

91	Methylbenzene	6.0

	Ethylbenzene	10.3

	1,4-Dimethylbenzene	10.9

	1,3-Dimethylbenzene	10.9

	1,2-Dimethylbenzene	11.9

105	1,3,5-Trimethylbenzene	15.1

	1,2,4-Trimethylbenzene	16.0

	1,2,3-Trimethylbenzene	17.4

156	2,6-Dimethylnaphthalene	28.9

	1,2-Dimethylnaphthalene	29.4

	1,3-Dimethylnaphthalene	29.7

Observe the presence of peaks in the EIPs that would confirm the
presence of any target aromatic compounds. Using the EIP areas and EIP
linear regression calibrations determine approximate crude oil
contamination in the sample for each of the target ions.

Qualitative Identification—See Section 6.17 of this method for
schematic flowchart.

Qualitative identification shall be accomplished by comparison of the
TIC and EIP area data from an authentic sample to the TIC and EIP area
data from the calibration standards (see Section 6.10.4). Crude oil
shall be identified by the presence of C10 to C13 n-alkanes and
corresponding target aromatics.

Using the calibration data, establish the identity of the C8 to C13
peaks in the chromatogram of the sample. Using the calibration data,
establish the identity of any target aromatics present on the extracted
ion scans.

Crude oil is not present in a detectable amount in the sample if there
are no target aromatics seen on the extracted ion scans. The experience
of the analyst shall weigh heavily in the determination of the presence
of peaks at a signal-to-noise ratio of 3 or greater.

If the chromatogram shows n-alkanes from C8 to C13 and target aromatics
to be present, contamination by crude oil or diesel shall be suspected
and quantitative analysis shall be determined. If there are no n-alkanes
present that are not seen on the blank, and no target aromatics are
seen, the sample can be considered to be free of contamination.

Quantitative Identification

Determine the area of the peaks from C8 to C13 as outlined in the
calibration section (Section   REF _Ref239045846 \r \h  <IP_ADDRESS> ). If
the area of the peaks for the sample is greater than that for the clean
NAF (base fluid) use the crude oil/drilling fluid calibration TIC linear
regression curve to determine approximate crude oil contamination.

Using the EIPs outlined in Section   REF _Ref239045888 \r \h  \*
MERGEFORMAT  <IP_ADDRESS> , determine the presence of any target aromatics.
Using the integration techniques outlined in Section   REF _Ref239045888
\r \h  \* MERGEFORMAT  <IP_ADDRESS> , obtain the EIP areas for m/z 91 and
105. Use the crude oil/drilling fluid calibration EIP linear regression
curves to determine approximate crude oil contamination.

Complex Samples

The most common interferences in the determination of crude oil can be
from mineral oil, diesel oil, and proprietary additives in drilling
fluids.

Mineral oil can typically be identified by its lower target aromatic
content, and narrow range of strong peaks.

Diesel oil can typically be identified by low amounts of n-alkanes from
C7 to C9, and the absence of n-alkanes greater than C25.

Crude oils can usually be distinguished by the presence of high
aromatics, increased intensities of C8 to C13 peaks, and/ or the
presence of higher hydrocarbons of C25 and greater (which may be
difficult to see in some synthetic fluids at low contamination levels).

Oil condensates from gas wells are low in molecular weight and will
normally produce strong chromatographic peaks in the C8–C13 range. If
a sample of the gas condensate crude oil from the formation is
available, the oil can be distinguished from other potential sources of
contamination by using it to prepare a calibration standard.

Asphaltene crude oils with API gravity < 20 may not produce
chromatographic peaks strong enough to show contamination at levels of
the calibration. Extracted ion peaks should be easier to see than
increased intensities for the C8 to C13 peaks. If a sample of asphaltene
crude from the formation is available, a calibration standard shall be
prepared.

System and Laboratory Performance

At the beginning of each 8-hour shift during which analyses are
performed, GC crude oil/drilling fluid calibration and system
performance test mixes shall be verified. For these tests, analysis of
the medium-level calibration standard (1-% Reference Oil in IO Lab
drilling fluid, and 1.25 mg/mL SPTM with internal standard) shall be
used to verify all performance criteria. Adjustments and/or
re-calibration (per Section   REF _Ref239046063 \r \h  \* MERGEFORMAT
6.10 ) shall be performed until all performance criteria are met. Only
after all performance criteria are met may samples and blanks be
analyzed.

Inject 1.0 µL of the medium-level GC/MS crude oil/drilling fluid
calibration standard into the GC instrument according to the procedures
in Section   REF _Ref239046095 \r \h  \* MERGEFORMAT  6.11.2 . Verify
that the linear regression curves for both TIC area and EIP areas are
still valid using this continuing calibration standard.

After this analysis is complete, inject 1.0 µL of the 1.25 mg/mL SPTM
(containing internal standard) into the GC instrument and verify the
proper retention times are met (see   REF _Ref238292711 \h  Table 6-2 ).

Retention times—Retention time of the internal standard. The absolute
retention time of the TCB internal standard shall be within the range
21.0 ±0.5 minutes. Relative retention times of the n-alkanes: The
retention times of the n-alkanes relative to the TCB internal standard
shall be similar to those given in   REF _Ref238292711 \h  Table 6-2 .

Calculations

The concentration of oil in NAFs drilling fluids shall be computed
relative to peak areas between C8 and C13 (using the Total Area
Integration method) or total peak areas from extracted ion profiles
(using the Extracted Ion Profile Method). In either case, there is a
measurable amount of peak area, even in clean drilling fluid samples,
due to spurious peaks and electrometer “noise” that contributes to
the total signal measured using either of the quantification methods. In
this procedure, a correction for this signal is applied, using the blank
or clean sample correction technique described in American Society for
Testing Materials (ASTM) Method D–3328–90, Comparison of Waterborne
Oil by Gas Chromatography. In this method, the “oil equivalents”
measured in a blank sample by total area gas chromatography are
subtracted from that determined for a field sample to arrive at the most
accurate measure of oil residue in the authentic sample.

Total Area Integration Method

Using C8 to C13 TIC area, the TCB area in the clean NAF sample and the
TIC linear regression curve, compute the oil equivalent concentration of
the C8 to C13 retention time range in the clean NAF.

Note: The actual TIC area of the C8 to C13 is equal to the C8 to C13
area minus the area of the TCB.

Using the corresponding information for the authentic sample, compute
the oil equivalent concentration of the C8 to C13 retention time range
in the authentic sample.

Calculate the concentration (% oil) of oil in the sample by subtracting
the oil equivalent concentration (% oil) found in the clean NAF from the
oil equivalent concentration (% oil) found in the authentic sample.

EIP Area Integration Method

Using either m/z 91 or 105 EIP areas, the TCB area in the clean NAF
sample, and the appropriate EIP linear regression curve, compute the oil
equivalent concentration of the in the clean NAF.

Using the corresponding information for the authentic sample, compute
its oil equivalent concentration.

Calculate the concentration (% oil) of oil in the sample by subtracting
the oil equivalent concentration (% oil) found in the clean NAF from the
oil equivalent concentration (% oil) found in the authentic sample.

Method Performance

Specification in this method are adopted from EPA Method 1663,
Differentiation of Diesel and Crude Oil by GC/FID (Section   REF
_Ref239163837 \r \h  6.16 , Reference 4).

Single laboratory method performance using an Internal Olefin (IO)
drilling fluid fortified at 0.5% oil using a 35 API gravity oil was:

Precision and accuracy 94 ±4%

Accuracy interval—86.3% to 102%

Relative percent difference in duplicate analysis—6.2%

Pollution Prevention

The solvent used in this method poses little threat to the environment
when recycled and managed properly.

Waste Management

It is the laboratory's responsibility to comply with all federal, state,
and local regulations governing waste management, particularly the
hazardous waste identification rules and land disposal restriction, and
to protect the air, water, and land by minimizing and controlling all
releases from fume hoods and bench operations. Compliance with all
sewage discharge permits and regulations is also required.

All authentic samples (drilling fluids) failing the RPE (fluorescence)
test (indicated by the presence of fluorescence) shall be retained and
classified as contaminated samples. Treatment and ultimate fate of these
samples is not outlined in this SOP.

For further information on waste management, consult “The Waste
Management Manual for Laboratory Personnel”, and “Less is Better:
Laboratory Chemical Management for Waste Reduction”, both available
from the American Chemical Society's Department of Government Relations
and Science Policy, 1155 16th Street NW, Washington, DC 20036.

References

Carcinogens—“Working With Carcinogens.” Department of Health,
Education, and Welfare, Public Health Service, Centers for Disease
Control (available through National Technical Information Systems, 5285
Port Royal Road, Springfield, VA 22161, document no. PB–277256):
August 1977.

“OSHA Safety and Health Standards, General Industry [29 CFR 1910],
Revised.” Occupational Safety and Health Administration, OSHA 2206.
Washington, DC: January 1976.

“Handbook of Analytical Quality Control in Water and Wastewater
Laboratories.” USEPA, EMSSL-CI, EPA–600/4–79–019. Cincinnati,
OH: March 1979.

“Method 1663, Differentiation of Diesel and Crude Oil by GC/FID,
Methods for the Determination of Diesel, Mineral, and Crude Oils in
Offshore Oil and Gas Industry Discharges, EPA 821–R–92–008, Office
of Water Engineering and Analysis Division, Washington, DC: December
1992.

U.S. EPA. 2001. Effluent Limitations Guidelines and New Source
Performance Standards for the Oil and Gas Extraction Point Source
Category. Federal Register, 66: 6849 (22 January 2001).

U.S. EPA. 2001. Effluent Limitations Guidelines and New Source
Performance Standards for the Oil and Gas Extraction Point Source
Category: Correction. Federal Register, 66: 30811 (8 June 2001).

Schematic Flowchart for Qualitative Identification

	Yes						No

  No

	                                	Yes

Figure   STYLEREF 1 \s  6 -  SEQ Figure \* ARABIC \s 1  1 .  Schematic
Flowchart for Qualitative Identification

Reverse Phase Extraction (RPE) Method for Detection of Oil
Contamination in Non-Aqueous Drilling Fluids (NAF) (EPA Method 1670)

Scope and Application

This method is used for determination of crude or formation oil, or
other petroleum oil contamination, in non-aqueous drilling fluids
(NAFs).

This method is intended as a positive/negative test to determine a
presence of crude oil in NAF prior to discharging drill cuttings from
offshore production platforms.

This method is for use in the Environmental Protection Agency's (EPA's)
survey and monitoring programs under the Clean Water Act, including
monitoring of compliance with the Gulf of Mexico NPDES General Permit
for monitoring of oil contamination in drilling fluids.

This method has been designed to show positive contamination for 5% of
representative crude oils at a concentration of 0.1% in drilling fluid
(vol/vol), 50% of representative crude oils at a concentration of 0.5%,
and 95% of representative crude oils at a concentration of 1%.

Any modification of this method, beyond those expressly permitted, shall
be considered a major modification subject to application and approval
of alternate test procedures under 40 CFR Parts 136.4 and 136.5.

Each laboratory that uses this method must demonstrate the ability to
generate acceptable results using the procedure in Section   REF
_Ref239046415 \r \h  \* MERGEFORMAT  7.9.2 .

Summary of Method

An aliquot of drilling fluid is extracted using isopropyl alcohol.

The mixture is allowed to settle and then filtered to separate out
residual solids.

An aliquot of the filtered extract is charged onto a reverse phase
extraction (RPE) cartridge.

The cartridge is eluted with isopropyl alcohol.

Crude oil contaminates are retained on the cartridge and their presence
(or absence) is detected based on observed fluorescence using a black
light.

Definitions

A NAF is one in which the continuous phase is a water immiscible fluid
such as an oleaginous material (e.g., mineral oil, enhance mineral oil,
paraffinic oil, or synthetic material such as olefins and vegetable
esters).

Interferences

Solvents, reagents, glassware, and other sample-processing hardware may
yield artifacts that affect results. Specific selection of reagents and
purification of solvents may be required.

All materials used in the analysis shall be demonstrated to be free from
interferences under the conditions of analysis by running laboratory
reagent blanks as described in Section   REF _Ref239046495 \r \h  \*
MERGEFORMAT  7.9.5 .

Safety

The toxicity or carcinogenicity of each reagent used in this method has
not been precisely determined; however, each chemical shall be treated
as a potential health hazard. Exposure to these chemicals should be
reduced to the lowest possible level. Material Safety Data Sheets
(MSDSs) shall be available for all reagents.

Isopropyl alcohol is flammable and should be used in a well-ventilated
area.

Unknown samples may contain high concentration of volatile toxic
compounds. Sample containers should be opened in a hood and handled with
gloves to prevent exposure. In addition, all sample preparation should
be conducted in a well-ventilated area to limit the potential exposure
to harmful contaminants. Drilling fluid samples should be handled with
the same precautions used in the drilling fluid handling areas of the
drilling rig.

This method does not address all safety issues associated with its use.
The laboratory is responsible for maintaining a safe work environment
and a current awareness file of OSHA regulations regarding the safe
handling of the chemicals specified in this method. A reference file of
material safety data sheets (MSDSs) shall be available to all personnel
involved in these analyses. Additional information on laboratory safety
can be found in Section   REF _Ref239164858 \r \h  7.16 , References 1
and 2.

Equipment and Supplies

Note: Brand names, suppliers, and part numbers are for illustrative
purposes only. No endorsement is implied. Equivalent performance may be
achieved using apparatus and materials other than those specified here,
but demonstration of equivalent performance that meets the requirements
of this method is the responsibility of the laboratory.

Sampling equipment.

Sample collection bottles/jars—New, pre-cleaned bottles/jars,
lot-certified to be free of artifacts. Glass preferable, plastic
acceptable, wide mouth approximately 1–L, with Teflon-lined screw cap.

Equipment for glassware cleaning.

Laboratory sink.

Oven—Capable of maintaining a temperature within ±5°C in the range
of 100–250°C.

Equipment for sample extraction.

Vials—Glass, 25 mL and 4 mL, with Teflon-lined screw caps, baked at
200–250°C for 1–h minimum prior to use.

Gas-tight syringes—Glass, various sizes, 0.5 mL to 2.5 mL (if spiking
of drilling fluids with oils is to occur).

Auto pipetters—various sizes, 0.1 mL, 0.5 mL, 1 to 5 mL delivery, and
10 mL delivery, with appropriate size disposable pipette tips,
calibrated to within ±0.5%.

Glass stirring rod.

Vortex mixer.

Disposable syringes—Plastic, 5 mL.

Teflon syringe filter, 25-mm, 0.45 µm pore size—Acrodisc®CR Teflon
(or equivalent).

Reverse Phase Extraction C18Cartridge—Waters Sep-Pak®Plus,
C18Cartridge, 360 mg of sorbent (or equivalent).

SPE vacuum manifold—Supelco Brand, 12 unit (or equivalent). Used as
support for cartridge/syringe assembly only. Vacuum apparatus not
required.

Equipment for fluorescence detection.

Black light—UV Lamp, Model UVG 11, Mineral Light Lamp, Shortwave 254
nm, or Longwave 365 nm, 15 volts, 60 Hz, 0.16 amps (or equivalent).

Black box—cartridge viewing area. A commercially available ultraviolet
viewing cabinet with viewing lamp, or alternatively, a cardboard box or
equivalent, approximately 14 inch × 7.5 inch × 7.5 inch; in size and
painted flat black inside. Lamp positioned in fitted and sealed slot in
center on top of box. Sample cartridges sit in a tray, ca. 6 inches from
lamp. Cardboard flaps cut on top panel and side of front panel for
sample viewing and sample cartridge introduction, respectively.

Viewing platform for cartridges. Simple support (hand made vial
tray—black in color) for cartridges so that they do not move during
the fluorescence testing.

Reagents and Standards

Isopropyl alcohol—99% purity.

NAF—Appropriate NAF as sent from the supplier (has not been circulated
downhole). Use the clean NAF corresponding to the NAF being used in the
current drilling operation.

Standard crude oil—NIST SRM 1582 petroleum crude oil.

Sample Collection, Preservation, and Storage

Collect approximately one liter of representative sample (NAF, which has
been circulated downhole) in a glass bottle or jar. Cover with a Teflon
lined cap. To allow for a potential need to re-analyze and/or re-process
the sample, it is recommended that a second sample aliquot be collected.

Label the sample appropriately.

All samples must be refrigerated at 0–4°C from the time of collection
until extraction (40 CFR Part 136, Table II).

All samples must be analyzed within 28 days of the date and time of
collection (40 CFR Part 136, Table II).

Quality Control

Each laboratory that uses this method is required to operate a formal
quality assurance program (Section   REF _Ref239165058 \r \h  7.16 ,
Reference 3). The minimum requirements of this program consist of an
initial demonstration of laboratory capability, and ongoing analyses of
blanks and spiked duplicates to assess accuracy and precision and to
demonstrate continued performance. Each field sample is analyzed in
duplicate to demonstrate representativeness.

The analyst shall make an initial demonstration of the ability to
generate acceptable accuracy and precision with this method. This
ability is established as described in Section   REF _Ref239046415 \r \h
 \* MERGEFORMAT  7.9.2 .

Preparation and analysis of a set of spiked duplicate samples to
document accuracy and precision. The procedure for the preparation and
analysis of these samples is described in Section   REF _Ref239047094 \r
\h  \* MERGEFORMAT  7.9.4 .

Analyses of laboratory reagent blanks are required to demonstrate
freedom from contamination. The procedure and criteria for preparation
and analysis of a reagent blank are described in Section   REF
_Ref239046495 \r \h  \* MERGEFORMAT  7.9.5 .

The laboratory shall maintain records to define the quality of the data
that is generated.

Accompanying QC for the determination of oil in NAF is required per
analytical batch. An analytical batch is a set of samples extracted at
the same time, to a maximum of 10 samples. Each analytical batch of 10
or fewer samples must be accompanied by a laboratory reagent blank
(Section   REF _Ref239046495 \r \h  \* MERGEFORMAT  7.9.5 ),
corresponding NAF reference blanks (Section   REF _Ref239047193 \r \h
\* MERGEFORMAT  7.9.6 ), a set of spiked duplicate samples blank
(Section   REF _Ref239047094 \r \h  \* MERGEFORMAT  7.9.4 ), and
duplicate analysis of each field sample. If greater than 10 samples are
to be extracted at one time, the samples must be separated into
analytical batches of 10 or fewer samples.

Initial demonstration of laboratory capability. To demonstrate the
capability to perform the test, the analyst shall analyze two
representative unused drilling fluids (e.g., internal olefin-based
drilling fluid, vegetable ester-based drilling fluid), each prepared
separately containing 0.1%, 1%, and 2% or a representative oil. Each
drilling fluid/concentration combination shall be analyzed 10 times, and
successful demonstration will yield the following average results for
the data set:

0.1% oil—Detected in <20% of samples

1% oil—Detected in >75% of samples

2% oil—Detected in >90% of samples

Sample duplicates.

The laboratory shall prepare and analyze (Section   REF _Ref239047297 \r
\h  \* MERGEFORMAT  7.11.2  and   REF _Ref239047318 \r \h  \*
MERGEFORMAT  7.11.4 ) each authentic sample in duplicate, from a given
sampling site or, if for compliance monitoring, from a given discharge.

The duplicate samples must be compared versus the prepared corresponding
NAF blank.

Prepare and analyze the duplicate samples according to procedures
outlined in Section   REF _Ref239047345 \r \h  \* MERGEFORMAT  7.11 .

The results of the duplicate analyses are acceptable if each of the
results give the same response (fluorescence or no fluorescence). If the
results are different, sample non-homogenicity issues may be a concern.
Prepare the samples again, ensuring a well-mixed sample prior to
extraction. Analyze the samples once again.

If different results are obtained for the duplicate a second time, the
analytical system is judged to be out of control and the problem shall
be identified and corrected, and the samples re-analyzed.

Spiked duplicates—Laboratory prepared spiked duplicates are analyzed
to demonstrate acceptable accuracy and precision.

Preparation and analysis of a set of spiked duplicate samples with each
set of no more than 10 field samples is required to demonstrate method
accuracy and precision and to monitor matrix interferences
(interferences caused by the sample matrix). A field NAF sample expected
to contain less than 0.5% crude oil (and documented to not fluoresce as
part of the sample batch analysis) shall be spiked with 1% (by volume)
of suitable reference crude oil and analyzed as field samples, as
described in Section   REF _Ref239047446 \r \h  \* MERGEFORMAT  7.11 .
If no low-level drilling fluid is available, then the unused NAF can be
used as the drilling fluid sample.

Laboratory reagent blanks—Laboratory reagent blanks are analyzed to
demonstrate freedom from contamination.

A reagent blank is prepared by passing 4 mL of the isopropyl alcohol
through a Teflon syringe filter and collecting the filtrate in a 4-mL
glass vial. A Sep Pak®C18cartridge is then preconditioned with 3 mL of
isopropyl alcohol. A 0.5-mL aliquot of the filtered isopropyl alcohol is
added to the syringe barrel along with 3.0 mL of isopropyl alcohol. The
solvent is passed through the preconditioned Sep Pak® cartridge. An
additional 2-mL of isopropyl alcohol is eluted through the cartridge.
The cartridge is now considered the “reagent blank” cartridge and is
ready for viewing (analysis). Check the reagent blank cartridge under
the black light for fluorescence. If the isopropyl alcohol and filter
are clean, no fluorescence will be observed.

If fluorescence is detected in the reagent blank cartridge, analysis of
the samples is halted until the source of contamination is eliminated
and a prepared reagent blank shows no fluorescence under a black light.
All samples shall be associated with an uncontaminated method blank
before the results may be reported for regulatory compliance purposes.

NAF reference blanks—NAF reference blanks are prepared from the NAFs
sent from the supplier (NAF that has not been circulated downhole) and
used as the reference when viewing the fluorescence of the test samples.

A NAF reference blank is prepared identically to the authentic samples.
Place a 0.1 mL aliquot of the “clean” NAF into a 25-mL glass vial.
Add 10 mL of isopropyl alcohol to the vial. Cap the vial. Vortex the
vial for approximately 10 sec. Allow the solids to settle for
approximately 15 minutes. Using a 5-mL syringe, draw up 4 mL of the
extract and filter it through a PTFE syringe filter, collecting the
filtrate in a 4-mL glass vial. Precondition a Sep Pak® C18 cartridge
with 3 mL of isopropyl alcohol. Add a 0.5-mL aliquot of the filtered
extract to the syringe barrel along with 3.0 mL of isopropyl alcohol.
Pass the extract and solvent through the preconditioned Sep Pak®
cartridge. Pass an additional 2-mL of isopropyl alcohol through the
cartridge. The cartridge is now considered the NAF blank cartridge and
is ready for viewing (analysis). This cartridge is used as the reference
cartridge for determining the absence or presence of fluorescence in all
authentic drilling fluid samples that originate from the same NAF. That
is, the specific NAF reference blank cartridge is put under the black
light along with a prepared cartridge of an authentic sample originating
from the same NAF material. The fluorescence or absence of fluorescence
in the authentic sample cartridge is determined relative to the NAF
reference cartridge.

Positive control solution, equivalent to 1% crude oil contaminated mud
extract, is prepared by dissolving 87 mg of standard crude oil into
10.00 mL of methylene chloride. Then mix 40 µL of this solution into
10.00 mL of IPA. Transfer 0.5 mL of this solution into a preconditioned
C18 cartridge, followed by 2 ml of IPA.

Calibration and Standardization

Calibration and standardization methods are not employed for this
procedure.

Procedure

This method is a screening-level test. Precise and accurate results can
be obtained only by strict adherence to all details.

Preparation of the analytical batch.

Bring the analytical batch of samples to room temperature.

Using a large glass stirring rod, mix the authentic sample thoroughly.

Using a large glass stirring rod, mix the clean NAF (sent from the
supplier) thoroughly.

Extraction.

Using an automatic positive displacement pipetter and a disposable
pipette tip transfer 0.1-mL of the authentic sample into a 25-mL vial.

Using an automatic pipetter and a disposable pipette tip dispense a
10-mL aliquot of solvent grade isopropyl alcohol (IPA) into the 25 mL
vial.

Cap the vial and vortex the vial for ca. 10–15 seconds.

Let the sample extract stand for approximately 5 minutes, allowing the
solids to separate.

Using a 5-mL disposable plastic syringe remove 4 mL of the extract from
the 25-mL vial.

Filter 4 mL of extract through a Teflon syringe filter (25-mm diameter,
0.45 µm pore size), collecting the filtrate in a labeled 4-mL vial.

Dispose of the PFTE syringe filter.

Using a black permanent marker, label a Sep Pak® C18 cartridge with the
sample identification.

Place the labeled Sep Pak® C18 cartridge onto the head of a SPE vacuum
manifold.

Using a 5-mL disposable plastic syringe, draw up exactly 3-mL (air free)
of isopropyl alcohol.

Attach the syringe tip to the top of the C18 cartridge.

Condition the C18 cartridge with the 3-mL of isopropyl alcohol by
depressing the plunger slowly.

Note: Depress the plunger just to the point when no liquid remains in
the syringe barrel. Do not force air through the cartridge. Collect the
eluate in a waste vial.

Remove the syringe temporarily from the top of the cartridge, then
remove the plunger, and finally reattach the syringe barrel to the top
of the C18 cartridge.

Using automatic pipetters and disposable pipette tips, transfer 0.5 mL
of the filtered extract into the syringe barrel, followed by a 3.0-mL
transfer of isopropyl alcohol to the syringe barrel.

Insert the plunger and slowly depress it to pass only the extract and
solvent through the preconditioned C18 cartridge.

Note: Depress the plunger just to the point when no liquid remains in
the syringe barrel. Do not force air through the cartridge. Collect the
eluate in a waste vial.

Remove the syringe temporarily from the top of the cartridge, then
remove the plunger, and finally reattach the syringe barrel to the top
of the C18 cartridge.

Using an automatic pipetter and disposable pipette tip, transfer 2.0 mL
of isopropyl alcohol to the syringe barrel.

Insert the plunger and slowly depress it to pass the solvent through the
C18 cartridge.

Note: Depress the plunger just to the point when no liquid remains in
the syringe barrel. Do not force air through the cartridge. Collect the
eluate in a waste vial.

Remove the syringe and labeled C18 cartridge from the top of the SPE
vacuum manifold.

Prepare a reagent blank according to the procedures outlined in Section
 REF _Ref239046495 \r \h  \* MERGEFORMAT  7.9.5 .

Prepare the necessary NAF reference blanks for each type of NAF
encountered in the field samples according to the procedures outlined in
Section   REF _Ref239047193 \r \h  \* MERGEFORMAT  7.9.6 .

Prepare the positive control (1% crude oil equivalent) according to
Section   REF _Ref239047796 \r \h  \* MERGEFORMAT  <IP_ADDRESS> .

Reagent blank fluorescence testing.

Place the reagent blank cartridge in a black box, under a black light.

Determine the presence or absence of fluorescence for the reagent blank
cartridge. If fluorescence is detected in the blank, analysis of the
samples is halted until the source of contamination is eliminated and a
prepared reagent blank shows no fluorescence under a black light. All
samples must be associated with an uncontaminated method blank before
the results may be reported for regulatory compliance purposes.

Sample fluorescence testing.

Place the respective NAF reference blank (Section   REF _Ref239047193 \r
\h  \* MERGEFORMAT  7.9.6 ) onto the tray inside the black box.

Place the authentic field sample cartridge (derived from the same NAF as
the NAF reference blank) onto the tray, adjacent and to the right of the
NAF reference blank.

Turn on the black light.

Compare the fluorescence of the sample cartridge with that of the
negative control cartridge (NAF blank, Section   REF _Ref239047881 \r \h
 \* MERGEFORMAT  <IP_ADDRESS> ) and positive control cartridge (1% crude oil
equivalent, Section   REF _Ref239047796 \r \h  \* MERGEFORMAT  <IP_ADDRESS>
).

If the fluorescence of the sample cartridge is equal to or brighter than
the positive control cartridge (1% crude oil equivalent, Section   REF
_Ref239047796 \r \h  \* MERGEFORMAT  <IP_ADDRESS>  ), the sample is
considered contaminated. Otherwise, the sample is clean.

Data Analysis and Calculations

Specific data analysis techniques and calculations are not performed in
this SOP.

Method Performance

This method was validated through a single laboratory study, conducted
with rigorous statistical experimental design and interpretation
(Section   REF _Ref239165431 \r \h  7.16 , Reference 4).

Pollution Prevention

The solvent used in this method poses little threat to the environment
when recycled and managed properly.

Waste Management

It is the laboratory's responsibility to comply with all Federal, State,
and local regulations governing waste management, particularly the
hazardous waste identification rules and land disposal restriction, and
to protect the air, water, and land by minimizing and controlling all
releases from bench operations. Compliance with all sewage discharge
permits and regulations is also required.

All authentic samples (drilling fluids) failing the fluorescence test
(indicated by the presence of fluorescence) shall be retained and
classified as contaminated samples. Treatment and ultimate fate of these
samples is not outlined in this SOP.

For further information on waste management, consult “The Waste
Management Manual for Laboratory Personnel,” and “Less is Better:
Laboratory Chemical Management for Waste Reduction,” both available
from the American Chemical Society's Department of Government Relations
and Science Policy, 1155 16th Street, NW, Washington, DC 20036.

References

“Carcinogen—Working with Carcinogens,” Department of Health,
Education, and Welfare, Public Health Service, Center for Disease
Control, National Institute for Occupational Safety and Health,
Publication No. 77–206, August 1977.

“OSHA Safety and Health Standards, General Industry,” (29 CFR 1910),
Occupational Safety and Health Administration, OSHA 2206 (Revised,
January 1976).

“Handbook of Analytical Quality Control in Water and Wastewater
Laboratories,” USEPA, EMSL-Ci, Cincinnati, OH 45268,
EPA–600/4–79–019, March 1979.

Report of the Laboratory Evaluation of Static Sheen Test
Replacements—Reverse Phase Extraction (RPE) Method for Detecting Oil
Contamination in Synthetic Based Mud (SBM). October 1998. Available from
API, 1220 L Street, NW, Washington, DC 20005–4070, 202–682–8000.

U.S. EPA. 2001. Effluent Limitations Guidelines and New Source
Performance Standards for the Oil and Gas Extraction Point Source
Category. Federal Register, 66: 6849 (22 January 2001).

U.S. EPA. 2001. Effluent Limitations Guidelines and New Source
Performance Standards for the Oil and Gas Extraction Point Source
Category: Correction. Federal Register, 66: 30811 (8 June 2001).

Determination of the Amount of Non-Aqueous Drilling Fluid (NAF) Base
Fluid from Drill Cuttings by a Retort Chamber (Derived from API
Recommended Practice 13B–2) (EPA Method 1674)

Description

This procedure is specifically intended to measure the amount of
non-aqueous drilling fluid (NAF) base fluid from cuttings generated
during a drilling operation. This procedure is a retort test which
measures all oily material (NAF base fluid) and water released from a
cuttings sample when heated in a calibrated and properly operating
“Retort” instrument.

In this retort test a known mass of cuttings is heated in the retort
chamber to vaporize the liquids associated with the sample. The NAF base
fluid and water vapors are then condensed, collected, and measured in a
precision graduated receiver.

Note: Obtaining a representative sample requires special attention to
the details of sample handling (e.g., location, method, frequency). See
Sections   REF _Ref239165594 \r \h  8.5  and   REF _Ref239165602 \r \h
8.6  for minimum requirements for collecting representative samples.
Additional sampling procedures in a given area may be specified by the
NPDES permit controlling authority.

Equipment

Retort instrument—The recommended retort instrument has a 50-cm3
volume with an external heating jacket.

Retort Specifications:

Retort assembly—retort body, cup and lid.

Material: 303 stainless steel or equivalent.

Volume: Retort cup with lid.

Cup Volume: 50- cm3.

Precision: ±0.25- cm3.

Condenser—capable of cooling the oil and water vapors below their
liquification temperature.

Heating jacket—nominal 350 watts.

Temperature control—capable of limiting temperature of retort to at
least 930°F (500°C) and enough to boil off all NAFs.

Liquid receiver (10- cm3, 20- cm3)—the 10- cm3 and 20- cm3 receivers
are specially designed cylindrical glassware with rounded bottom to
facilitate cleaning and funnel-shaped top to catch falling drops. For
compliance monitoring under the NPDES program, the analyst shall use the
10- cm3 liquid receiver with 0.1 ml graduations to achieve greater
accuracy.

Receiver specifications:

Total volume: 10- cm3, 20- cm3.

Precision (0 to 100%): ±0.05 cm3, ±0.05 cm3.

Outside diameter: 10-mm, 13-mm.

Wall thickness: 1.5 ±0.1mm, 1.2 ±0.1mm.

Frequency of graduation marks (0 to 100%): 0.10- cm3, 0.10- cm3.

Calibration: To contain “TC” @ 20°C.

Scale: cm3, cm3.

Material—Pyrex® or equivalent glass.

Toploading balance—capable of weighing 2,000 g and precision of at
least 0.1 g. Unless motion is a problem, the analyst shall use an
electronic balance. Where motion is a problem, the analyst may use a
triple beam balance.

Fine steel wool (No. 000)—for packing retort body.

Thread sealant lubricant: high temperature lubricant, e.g. Never-Seez®
or equivalent.

Pipe cleaners—to clean condenser and retort stem.

Brush—to clean receivers.

Retort spatula—to clean retort cup.

Corkscrew—to remove spent steel wool.

Procedure

Clean and dry the retort assembly and condenser.

Pack the retort body with steel wool.

Apply lubricant/sealant to threads of retort cup and retort stem.

Weigh and record the total mass of the retort cup, lid, and retort body
with steel wool. This is mass (A), grams.

Collect a representative cuttings sample (see Note in Section   REF
_Ref239048141 \r \h  \* MERGEFORMAT  8.1 ).

Partially fill the retort cup with cuttings and place the lid on the
cup.

Screw the retort cup (with lid) onto the retort body, weigh and record
the total mass. This is mass (B), grams.

Attach the condenser. Place the retort assembly into the heating jacket.

Weigh and record the mass of the clean and dry liquid receiver. This is
mass (C), grams. Place the receiver below condenser outlet.

Turn on the retort. Allow it to run a minimum of 1 hour.

Note: If solids boil over into receiver, the test shall be rerun. Pack
the retort body with a greater amount of steel wool and repeat the test.

Remove the liquid receiver. Allow it to cool. Record the volume of water
recovered. This is (V), cm3.

Note: If an emulsion interface is present between the oil and water
phases, heating the interface may break the emulsion. As a suggestion,
remove the retort assembly from the heating jacket by grasping the
condenser. Carefully heat the receiver along the emulsion band by gently
touching the receiver for short intervals with the hot retort assembly.
Avoid boiling the liquids. After the emulsion interface is broken, allow
the liquid receiver to cool. Read the water volume at the lowest point
of the meniscus.

Weigh and record the mass of the receiver and its liquid contents (oil
plus water). This is mass (D), grams.

Turn off the retort. Remove the retort assembly and condenser from the
heating jacket and allow them to cool. Remove the condenser.

Weigh and record the mass of the cooled retort assembly without the
condenser. This is mass (E), grams.

Clean the retort assembly and condenser.

Calculations

− A	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  1 ]

Mass of the dry retorted cuttings (MD) equals the mass of the cooled
retort assembly (E) minus the mass of the empty retort assembly (A).

	MD = E − A	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  2 ]

Mass of the NAF base fluid (MBF) equals the mass of the liquid receiver
with its contents (D) minus the sum of the mass of the dry receiver (C)
and the mass of the water (V).

	MBF = D − (C + V)	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1
3 ]

Note: Assuming the density of water is 1 g/cm3, the volume of water is
equivalent to the mass of the water.

Mass balance requirement:

The sum of MD, MBF, and V shall be within 5% of the mass of the wet
sample.

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  4 ]

The procedure shall be repeated if this requirement is not met.

Reporting oil from cuttings:

Assume that all oil recovered is NAF base fluid.

The mass percent NAF base fluid retained on the cuttings (%BFi) for the
sampled discharge “i” is equal to 100 times the mass of the NAF base
fluid (MBF) divided by the mass of the wet cuttings sample (Mw).

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  5 ]

Operators discharging small volume NAF-cuttings discharges which do not
occur during a NAF-cuttings discharge sampling interval (i.e., displaced
interfaces, accumulated solids in sand traps, pit clean-out solids, or
centrifuge discharges while cutting mud weight) shall either: (a)
Measure the mass percent NAF base fluid retained on the cuttings
(%BFSVD) for each small volume NAF-cuttings discharges; or (b) use a
default value of 25% NAF base fluid retained on the cuttings.

The mass percent NAF base fluid retained on the cuttings is determined
for all cuttings wastestreams and includes fines discharges and any
accumulated solids discharged. (See Section   REF _Ref239166859 \r \h
<IP_ADDRESS>  for procedures on measuring or estimating the mass percent NAF
base fluid retained on the cuttings (%BF) for dual gradient drilling
seafloor discharges performed to ensure proper operation of subsea
pumps.)

A mass NAF-cuttings discharge fraction (X, unitless) is calculated for
all NAF-cuttings, fines, or accumulated solids discharges every time a
set of retorts is performed (Section   REF _Ref239166859 \r \h  <IP_ADDRESS>
for procedures on measuring or estimating the mass NAF-cuttings
discharge fraction (X) for dual gradient drilling seafloor discharges
performed to ensure proper operation of subsea pumps). The mass
NAF-cuttings discharge fraction (X) combines the mass of NAF-cuttings,
fines, or accumulated solids discharged from a particular discharge over
a set period of time with the total mass of NAF-cuttings, fines, or
accumulated solids discharged into the ocean during the same period of
time (see Sections   REF _Ref239165630 \r \h  8.5  and   REF
_Ref239165639 \r \h  8.6 ). The mass NAF-cuttings discharge fraction (X)
for each discharge is calculated by direct measurement as:

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  6 ]

Where:

Xi	=	Mass NAF-cuttings discharge fraction for NAF-cuttings, fines, or
accumulated solids discharge “i”, (unitless)

Fi	=	Mass of NAF-cuttings discharged from NAF-cuttings, fines, or
accumulated solids discharge “i” over a specified period of time
(see Sections   REF _Ref239165630 \r \h  8.5  and   REF _Ref239165639 \r
\h  8.6 ), (kg)

G	=	Mass of all NAF-cuttings discharges into the ocean during the same
period of time as used to calculate Fi, (kg)

If an operator has more than one point of NAF-cuttings discharge, the
mass faction (Xi) must be determined by: (a) Direct measurement (see
Equation 8-6); (b) using the following default values of 0.85 and 0.15
for the cuttings dryer (e.g., horizontal centrifuge, vertical
centrifuge, squeeze press, High-G linear shakers) and fines removal unit
(e.g., decanting centrifuges, mud cleaners), respectively, when the
operator is only discharging from the cuttings dryer and the fines
removal unit; or (c) using direct measurement of “Fi” (see Equation
8-6) for fines and accumulated solids, using Equation 8-6A to calculate
“GEST” for use as “G” in Equation 8-6, and calculating the mass
(kg) of NAF-cuttings discharged from the cuttings dryer (Fi) as the
difference between the mass of “GEST” calculated in Equation 8-6A
(kg) and the sum of all fines and accumulated solids mass directly
measured (kg) (see Equation 8-6).

GEST = Estimated mass of all NAF-cuttings discharges into the ocean

during the same period of time as used to calculate Fi

	(see Equation 8-6), (kg)	[8-6A]

Where:

GEST	= 	Hole Volume (bbl) × (396.9 kg/bbl) × (1 + Z/100)

Z	= 	The base fluid retained on cuttings limitation or standard (%)
which apply to the NAF being discharge (see 40 CFR§§435.13. and
435.15).

Hole Volume (bbl)	=	[Cross-Section Area of NAF interval (in2)] ×
Average Rate of Penetration (feet/hr) × period of time (min) used to
calculate Fi (see Equation 8-6) × (1 hr/60 min) × (1 bbl/5.61 ft3) ×
(1 ft/12 in)2

Cross-Section Area of NAF interval (in2)	=	(3.14 × [Bit Diameter
(in)]2)/4

Bit Diameter (in)	=	Diameter of drilling bit for the NAF interval
producing drilling cuttings during the same period of time as used to
calculate Fi (see Equation 8-6)

Average Rate of Penetration (feet/hr)	=	Arithmetic average of rate of
penetration into the formation during the same period of time as used to
calculate Fi (see Equation 8-6)

Note: Operators with one NAF-cuttings discharge may set the mass
NAF-cuttings discharge fraction (Xi) equal to 1.0.

Each NAF-cuttings, fines, or accumulated solids discharge has an
associated mass percent NAF base fluid retained on cuttings value (%BF)
and mass NAF-cuttings discharge fraction (X) each time a set of retorts
is performed. A single total mass percent NAF base fluid retained on
cuttings value (%BFT) is calculated every time a set of retorts is
performed. The single total mass percent NAF base fluid retained on
cuttings value (%BFT) is calculated as:

= Σ(Xi) × (%BFi)	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  7
]

Where:

%BFT,j	= 	Total mass percent NAF base fluid retained on cuttings value
for retort set “j” (unitless as percentage, %)

Xi	= 	Mass NAF-cuttings discharge fraction for NAF-cuttings, fines, or
accumulated solids discharge “i”, (unitless)

%BFi	= 	Mass percent NAF base fluid retained on the cuttings for
NAF-cuttings, fines, or accumulated solids discharge “i” , (unitless
as percentage, %)

Note: ΣXi= 1.

Operators with one NAF-cuttings discharge may set %BFT,j equal to %BFi.

Operators performing dual gradient drilling operations may require
seafloor discharges of large cuttings (>1/4′) to ensure the proper
operation of subsea pumps (e.g., electrical submersible pumps).
Operators performing dual gradient drilling operations which lead to
seafloor discharges of large cuttings for the proper operation of subsea
pumps shall either: (a) Measure the mass percent NAF base fluid retained
on cuttings value (%BF) and mass NAF-cuttings discharge fraction (X) for
seafloor discharges each time a set of retorts is performed; (b) use the
following set of default values, (%BF = 14%; X = 0.15); or (c) use a
combination of (a) and (b) (e.g., use a default value for %BF and
measure X).

Additionally, operators performing dual gradient drilling operations
which lead to seafloor discharges of large cuttings for the proper
operation of subsea pumps shall also perform the following tasks:

Use side scan sonar or shallow seismic to determine the presence of high
density chemosynthetic communities. Chemosynthetic communities are
assemblages of tube worms, clams, mussels, and bacterial mats that occur
at natural hydrocarbon seeps or vents, generally in water depths of 500
meters or deeper. Seafloor discharges of large cuttings for the proper
operation of subsea pumps shall not be permitted within 1,000 feet of a
high density chemosynthetic community.

Seafloor discharges of large cuttings for the proper operation of subsea
pumps shall be visually monitored and documented by a Remotely Operated
Vehicle (ROV) within the tether limit (approximately 300 feet). The
visual monitoring shall be conducted prior to each time the discharge
point is relocated (cuttings discharge hose) and conducted along the
same direction as the discharge hose position. Near-seabed currents
shall be obtained at the time of the visual monitoring.

Seafloor discharges of large cuttings for the proper operation of subsea
pumps shall be directed within a 150 foot radius of the wellbore.

The weighted mass ratio averaged over all NAF well sections (%BFwell) is
the compliance value that is compared with the “maximum weighted mass
ratio averaged over all NAF well sections” BAT discharge limitations
(see the table in 40 CFR §435.13 and footnote 5 of the table in 40 CFR
§435.43) or the “maximum weighted mass ratio averaged over all NAF
well sections” NSPS discharge limitations (see the table in 40 CFR
§435.15 and footnote 5 of the table in 40 CFR §435.45). The weighted
mass ratio averaged over all NAF well sections (%BFwell) is calculated
as the arithmetic average of all total mass percent NAF base fluid
retained on cuttings values (%BFT) and is given by the following
expression:

   SHAPE  \* MERGEFORMAT   	[  STYLEREF 1 \s  8 -  SEQ Equation \*
ARABIC \s 1  8 ]

Where:

%BFwell	= 	Weighted mass ratio averaged over all NAF well sections
(unitless as percentage, %)

%BFT,j	=	Total mass percent NAF base fluid retained on cuttings value
for retort set “j” (unitless as percentage, %)

n 	= 	Total number of retort sets performed over all NAF well sections
(unitless)

Small volume NAF-cuttings discharges which do not occur during a
NAF-cuttings discharge sampling interval (i.e., displaced interfaces,
accumulated solids in sand traps, pit clean-out solids, or centrifuge
discharges while cutting mud weight) shall be mass averaged with the
arithmetic average of all total mass percent NAF base fluid retained on
cuttings values (see Equation 8-8). An additional sampling interval
shall be added to the calculation of the weighted mass ratio averaged
over all NAF well sections (%BFwell). The mass fraction of the small
volume NAF-cuttings discharges (XSVD) will be determined by dividing the
mass of the small volume NAF-cuttings discharges (FSVD) by the total
mass of NAF-cuttings discharges for the well drilling operation (Gwell+
FSVD).

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  9 ]

Where:

XSVD	= 	Mass fraction of the small volume NAF-cuttings discharges
(unitless)

FSVD	= 	Mass of the small volume NAF-cuttings discharges (kg)

Gwell	= 	Mass of total NAF-cuttings from the well (kg)

The mass of small volume NAF-cuttings discharges (FSVD) shall be
determined by multiplying the density of the small volume NAF-cuttings
discharges (ρsvd) times the volume of the small volume NAF-cuttings
discharges (VSVD).

	FSVD = ρsvd × VSVD	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1
 10 ]

Where:

FSVD	= 	Mass of small volume NAF-cuttings discharges (kg)

ρsvd	= 	Density of the small volume NAF-cuttings discharges (kg/bbl)

VSVD	= 	Volume of the small volume NAF-cuttings discharges (bbl)

The density of the small volume NAF-cuttings discharges shall be
measured. The volume of small volume discharges (VSVD) shall be either:
(a) Be measured or (b) use default values of 10 bbl of SBF for each
interface loss and 75 bbl of SBM for pit cleanout per well.

The total mass of NAF-cuttings discharges for the well (Gwell) shall be
either: (a) Measured; or (b) calculated by multiplying 1.0 plus the
arithmetic average of all total mass percent NAF base fluid retained on
cuttings values [see Equation 8-8] times the total hole volume (Vwell)
for all NAF well sections times a default value for the density the
formation of 2.5 g/cm3 (396.9 kg/bbl).

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  11 ]

Where:

Gwell	= 	Total mass of NAF-cuttings discharges for the well (kg)

	= 	see Equation 8-8 (unitless as a percentage)

Vwell	= 	Total hole volume (Vwell) for all NAF well sections (bbl)

The total hole volume of NAF well sections (Vwell) will be calculated
as:

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  12 ]

For wells where small volume discharges associated with cuttings are
made, %BFwell becomes:

 	[  STYLEREF 1 \s  8 -  SEQ Equation \* ARABIC \s 1  13 ]

Note: See Sections   REF _Ref239165630 \r \h  8.5  and   REF
_Ref239165639 \r \h  8.6  to determine the sampling frequency to
determine the total number of retort sets required for all NAF well
sections.

The total number of retort sets (n) is increased by 1 for each sampling
interval (see Section   REF _Ref239059501 \r \h  <IP_ADDRESS> ) when all NAF
cuttings, fines, or accumulated solids for that sampling interval are
retained for no discharge. A zero discharge interval shall be at least
500 feet up to a maximum of three per day. This action has the effect of
setting the total mass percent NAF base fluid retained on cuttings value
(%BFT) at zero for that NAF sampling interval when all NAF cuttings,
fines, or accumulated solids are retained for no discharge.

Operators that elect to use the Best Management Practices (BMPs) for
NAF-cuttings shall use the procedures outlined in Section   REF
_Ref239165834 \r \h  8.6 .

Requirements for Sampling Cuttings Discharge Streams for use with this
Method

Sampling Locations

Each NAF-cuttings waste stream that discharges into the ocean shall be
sampled and analyzed as detailed earlier in Section   REF _Ref239168941
\r \h  8 . NAF-cuttings discharges to the ocean may include discharges
from primary shakers, secondary shakers, cuttings dryer, fines removal
unit, accumulated solids, and any other cuttings separation device whose
NAF-cuttings waste is discharged to the ocean. NAF-cuttings wastestreams
not directly discharged to the ocean (e.g., NAF-cuttings generated from
shake shakers and sent to a cuttings dryer for additional processing) do
not require sampling and analysis.

The collected samples shall be representative of each NAF-cuttings
discharge. Operators shall conduct sampling to avoid the serious
consequences of error (i.e., bias or inaccuracy). Operators shall
collect NAF-cuttings samples near the point of origin and before the
solids and liquid fractions of the stream have a chance to separate from
one another. For example, operators shall collect shale shaker
NAF-cuttings samples at the point where NAF-cuttings are coming off the
shale shaker and not from a holding container downstream where
separation of larger particles from the liquid can take place.

Operators shall provide a simple schematic diagram of the solids control
system and sample locations to the NPDES permit controlling authority.

Type of Sample and Sampling Frequency

Each NAF-cuttings, fines, or accumulated solids discharge has an
associated mass percent NAF base fluid retained on cuttings value (%BF)
and mass NAF-cuttings discharge fraction (X) for each sampling interval
(see Section   REF _Ref239059501 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ).
Operators shall collect a single discrete NAF-cuttings sample for each
NAF-cuttings waste stream discharged to the ocean during every sampling
interval.

Operators shall use measured depth in feet from the Kelly bushing when
samples are collected.

The NAF-cuttings samples collected for the mass fraction analysis (see
Equation 8-6) shall also be used for the retort analysis (see Equations
8-1 through 8-5).

Operators shall collect and analyze at least one set of NAF-cuttings
samples per day while discharging. Operators engaged in fast drilling
(i.e., greater than 500 linear NAF feet advancement of drill bit per
day) shall collect and analyze one set of NAF-cuttings samples per 500
linear NAF feet of footage drilled. Operators are not required to
collect and analyze more than three sets of NAF-cuttings samples per day
(i.e., three sampling intervals). Operators performing zero discharge of
all NAF-cuttings (i.e., all NAF cuttings, fines, or accumulated solids
retained for no discharge) shall use the following periods to count
sampling intervals: (1) One sampling interval per day when drilling is
less than 500 linear NAF feet advancement of drill bit per day; and (2)
one sampling interval per 500 linear NAF feet of footage drilled with a
maximum of three sampling intervals per day.

The operator shall measure the individual masses (Fi, kg) and sum total
mass (G, kg) (see Equation 8-6) over a representative period of time
(e.g., <10 minutes) during steady-state conditions for each sampling
interval (see Section   REF _Ref239059501 \r \h  \* MERGEFORMAT  <IP_ADDRESS>
). The operator shall ensure that all NAF-cuttings are capture for mass
analysis during the same sampling time period (e.g., <10 minutes) at
approximately the same time (i.e., all individual mass samples collected
within one hour of each other).

Operators using Best Management Practices (BMPs) to control NAF-cuttings
discharges shall follow the procedures in Section   REF _Ref239166385 \r
\h  8.6 .

Sample Size and Handling

The volume of each sample depends on the volumetric flow rate (cm3/s) of
the NAF-cuttings stream and the sampling time period (e.g., <10
minutes). Consequently, different solids control equipment units
producing different NAF-cuttings waste streams at different volumetric
flow rates will produce different size samples for the same period of
time. Operators shall use appropriately sized sample containers for each
NAF-cuttings waste stream to ensure no NAF-cuttings are spilled during
sample collection. Operators shall use the same time period (e.g., <10
minutes) to collect NAF-cuttings samples from each NAF-cuttings waste
stream. Each NAF-cuttings sample size shall be at least one gallon.
Operators shall clearly mark each container to identify each
NAF-cuttings sample.

Operators shall not decant, heat, wash, or towel the NAF-cuttings to
remove NAF base fluid before mass and retort analysis.

Operators shall first calculate the mass of each NAF-cuttings sample and
perform the mass ratio analysis (see Equation 8-6). Operators with only
one NAF-cuttings discharge may skip this step (see Section   REF
_Ref239168752 \r \h  <IP_ADDRESS> ).

Operators shall homogenize (e.g., stirring, shaking) each NAF-cuttings
sample prior to placing a sub-sample into the retort cup. The bottom of
the NAF-cuttings sample container shall be examined to be sure that
solids are not sticking to it.

Operators shall then calculate the NAF base fluid retained on cuttings
using the retort procedure (See Equations 8-1 through 8-5). Operators
shall start the retort analyses no more than two hours after collecting
the first individual mass sample for the sampling interval .

Operators shall not discharge any sample before successfully completing
the mass and retort analyses [i.e., mass balance requirements (see
Section   REF _Ref239168784 \r \h  8.4.2 ) are satisfied]. Operators
shall immediately re-run the retort analyses if the mass balance
requirements (see Equation 8-4) are not within a tolerance of 5% (see
Section   REF _Ref239168784 \r \h  8.4.2 , Equation 8-4).

Calculations

Operators shall calculate a set of mass percent NAF base fluid retained
on cuttings values (%BF) and mass NAF-cuttings discharge fractions (X)
for each NAF-cuttings waste stream (see Section   REF _Ref239060447 \r
\h  \* MERGEFORMAT  <IP_ADDRESS> ) for each sampling interval (see Section
REF _Ref239059501 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ) using the procedures
outlined earlier in Section   REF _Ref239168918 \r \h  8 .

Operators shall tabulate the following data for each individual
NAF-cuttings sample: (1) Date and time of NAF-cuttings sample
collection; (2) time period of NAF-cuttings sample collection (see
Section   REF _Ref239060572 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ); (3) mass
and volume of each NAF-cuttings sample; (4) measured depth (feet) at
NAF-cuttings sample collection (see Section   REF _Ref239060636 \r \h
\* MERGEFORMAT  <IP_ADDRESS> ); (5) respective linear feet of hole drilled
represented by the NAF-cuttings sample (feet); and (6) the drill bit
diameter (inches) used to generate the NAF-cuttings sample cuttings.

Operators shall calculate a single total mass percent NAF base fluid
retained on cuttings value (%BFT) for each sampling interval (see
Section   REF _Ref239059501 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ) using the
procedures outlined in Section   REF _Ref239169625 \r \h  8.4 .

Operators shall tabulate the following data for each total mass percent
NAF base fluid retained on cuttings value (%BFT) for each NAF-cuttings
sampling interval: (1) Date and starting and stopping times of
NAF-cuttings sample collection and retort analyses; (2) measured depth
of well (feet) at start of NAF-cuttings sample collection (see Section
REF _Ref239060636 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ); (3) respective
linear feet of hole drilled represented by the NAF-cuttings sample
(feet); (4) the drill bit diameter (inches) used to generate the
NAF-cuttings sample cuttings; and (5) annotation when zero discharge of
NAF-cuttings is performed.

Operators shall calculate the weighted mass ratio averaged over all NAF
well sections (%BFwell) using the procedures outlined in Section   REF
_Ref239169625 \r \h  8.4 .

Operators shall tabulate the following data for each weighted mass ratio
averaged over all NAF well sections (%BFwell) for each NAF well: (1)
Starting and stopping dates of NAF well sections; (2) measured depth
(feet) of all NAF well sections; (3) total number of sampling intervals
(see Sections   REF _Ref239059501 \r \h  \* MERGEFORMAT  <IP_ADDRESS>  and
REF _Ref239060748 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ); (4) number of
sampling intervals tabulated during any zero discharge operations; (5)
total volume of zero discharged NAF-cuttings over entire NAF well
sections; and (6) identification of whether BMPs were employed (see
Section   REF _Ref239168973 \r \h  8.6 ).

Best Management Practices (BMPs) for use with this Method

Overview of BMPs

Best Management Practices (BMPs) are inherently pollution prevention
practices. BMPs may include the universe of pollution prevention
encompassing production modifications, operational changes, material
substitution, materials and water conservation, and other such measures.
BMPs include methods to prevent toxic and hazardous pollutants from
reaching receiving waters. Because BMPs are most effective when
organized into a comprehensive facility BMP Plan, operators shall
develop a BMP in accordance with the requirements in this addendum.

The BMP requirements contained in this section were compiled from
several Regional permits, an EPA guidance document (i.e., Guidance
Document for Developing Best Management Practices (BMP)” (EPA
833–B–93–004, U.S. EPA, 1993)), and draft industry BMPs. These
common elements represent the appropriate mix of broad directions needed
to complete a BMP Plan along with specific tasks common to all drilling
operations.

Operators are not required to use BMPs if all NAF-cuttings discharges
are monitored in accordance with Sections   REF _Ref239169012 \r \h  8.1
 through   REF _Ref239169025 \r \h  8.4 .

BMP Plan Purpose and Objectives

Operators shall design the BMP Plan to prevent or minimize the
generation and the potential for the discharge of NAF from the facility
to the waters of the United States through normal operations and
ancillary activities. The operator shall establish specific objectives
for the control of NAF by conducting the following evaluations.

The operator shall identify and document each NAF well that uses BMPs
before starting drilling operations and the anticipated total feet to be
drilled with NAF for that particular well.

Each facility component or system controlled through use of BMPs shall
be examined for its NAF-waste minimization opportunities and its
potential for causing a discharge of NAF to waters of the United States
due to equipment failure, improper operation, natural phenomena (e.g.,
rain, snowfall).

For each NAF wastestream controlled through BMPs where experience
indicates a reasonable potential for equipment failure (e.g., a tank
overflow or leakage), natural condition (e.g., precipitation), or other
circumstances to result in NAF reaching surface waters, the BMP Plan
shall include a prediction of the total quantity of NAF which could be
discharged from the facility as a result of each condition or
circumstance.

BMP Plan Requirements

The BMP Plan may reflect requirements within the pollution prevention
requirements required by the Minerals Management Service (see 30 CFR
250.300) or other Federal or State requirements and incorporate any part
of such plans into the BMP Plan by reference.

The operator shall certify that its BMP Plan is complete, on-site, and
available upon request to EPA or the NPDES Permit controlling authority.
This certification shall identify the NPDES permit number and be signed
by an authorized representative of the operator. This certification
shall be kept with the BMP Plan. For new or modified NPDES permits, the
certification shall be made no later than the effective date of the new
or modified permit. For existing NPDES permits, the certification shall
be made within one year of permit issuance.

The BMP Plan shall:

Be documented in narrative form, and shall include any necessary plot
plans, drawings or maps, and shall be developed in accordance with good
engineering practices. At a minimum, the BMP Plan shall contain the
planning, development and implementation, and evaluation/reevaluation
components. Examples of these components are contained in “Guidance
Document for Developing Best Management Practices (BMP)” (EPA
833–B–93–004, U.S. EPA, 1993).

Include the following provisions concerning BMP Plan review.

Be reviewed by permittee's drilling engineer and offshore installation
manager (OIM) to ensure compliance with the BMP Plan purpose and
objectives set forth in Section   REF _Ref239061899 \r \h  \*
MERGEFORMAT  8.6.2 .

Include a statement that the review has been completed and that the BMP
Plan fulfills the BMP Plan purpose and objectives set forth in Section
REF _Ref239061899 \r \h  \* MERGEFORMAT  8.6.2 . This statement shall
have dated signatures from the permittee's drilling engineer and
offshore installation manager and any other individuals responsible for
development and implementation of the BMP Plan.

Address each component or system capable of generating or causing a
release of significant amounts of NAF and identify specific preventative
or remedial measures to be implemented.

BMP Plan Documentation

The operator shall maintain a copy of the BMP Plan and related
documentation (e.g., training certifications, summary of the monitoring
results, records of NAF-equipment spills, repairs, and maintenance) at
the facility and shall make the BMP Plan and related documentation
available to EPA or the NPDES Permit controlling authority upon request.

BMP Plan Modification

For those NAF wastestreams controlled through BMPs, the operator shall
amend the BMP Plan whenever there is a change in the facility or in the
operation of the facility which materially increases the generation of
those NAF-wastes or their release or potential release to the receiving
waters.

At a minimum the BMP Plan shall be reviewed once every five years and
amended within three months if warranted. Any such changes to the BMP
Plan shall be consistent with the objectives and specific requirements
listed in this addendum. All changes in the BMP Plan shall be reviewed
by the permittee's drilling engineer and offshore installation manager.

At any time, if the BMP Plan proves to be ineffective in achieving the
general objective of preventing and minimizing the generation of
NAF-wastes and their release and potential release to the receiving
waters and/or the specific requirements in this addendum, the permit
and/or the BMP Plan shall be subject to modification to incorporate
revised BMP requirements.

Specific Pollution Prevention Requirements for NAF Discharges Associated
with Cuttings

The following specific pollution prevention activities are required in a
BMP Plan when operators elect to control NAF discharges associated with
cuttings by a set of BMPs.

Establishing programs for identifying, documenting, and repairing
malfunctioning NAF equipment, tracking NAF equipment repairs, and
training personnel to report and evaluate malfunctioning NAF equipment.

Establishing operating and maintenance procedures for each component in
the solids control system in a manner consistent with the manufacturer's
design criteria.

Using the most applicable spacers, flushes, pills, and displacement
techniques in order to minimize contamination of drilling fluids when
changing from water-based drilling fluids to NAF and vice versa.

A daily retort analysis shall be performed (in accordance with Sections
 REF _Ref239169371 \r \h  8.1  through   REF _Ref239169382 \r \h  8.4 )
during the first 0.33 X feet drilled with NAF where X is the anticipated
total feet to be drilled with NAF for that particular well. The retort
analyses shall be documented in the well retort log. The operators shall
use the calculation procedures detailed in Section   REF _Ref239169382
\r \h  8.4  (see Equations 8-1 through 8-8) to determine the arithmetic
average (%BFwell) of the retort analyses taken during the first 0.33 X
feet drilled with NAF.

When the arithmetic average (%BFwell) of the retort analyses taken
during the first 0.33 X feet drilled with NAF is less than or equal to
the base fluid retained on cuttings limitation or standard (see 40 CFR
§§435.13 and 435.15), retort monitoring of cuttings may cease for that
particular well. The same BMPs and drilling fluid used during the first
0.33 X feet shall be used for all remaining NAF sections for that
particular well.

When the arithmetic average (%BFwell) of the retort analyses taken
during the first 0.33 X feet drilled with NAF is greater the base fluid
retained on cuttings limitation or standard (see 40 CFR §§435.13 and
435.15), retort monitoring shall continue for the following (second)
0.33 X feet drilled with NAF where X is the anticipated total feet to be
drilled with NAF for that particular well. The retort analyses for the
first and second 0.33 X feet shall be documented in the well retort log.

When the arithmetic average (%BFwell) of the retort analyses taken
during the first 0.66 X feet (i.e., retort analyses taken from first and
second 0.33 X feet) drilled with NAF is less than or equal to the base
fluid retained on cuttings limitation or standard (see 40 CFR §§435.13
and 435.15), retort monitoring of cuttings may cease for that particular
well. The same BMPs and drilling fluid used during the first 0.66 X feet
shall be used for all remaining NAF sections for that particular well.

When the arithmetic average (%BFwell) of the retort analyses taken
during the first 0.66 X feet (i.e., retort analyses taken from first and
second 0.33 X feet) drilled with NAF is greater than the base fluid
retained on cuttings limitation or standard (see 40 CFR §§435.13 and
435.15), retort monitoring shall continue for all remaining NAF sections
for that particular well. The retort analyses for all NAF sections shall
be documented in the well retort log.

When the arithmetic average (%BFwell) of the retort analyses taken over
all NAF sections for the entire well is greater that the base fluid
retained on cuttings limitation or standard (see 40 CFR §§435.13 and
435.15), the operator is in violation of the base fluid retained on
cuttings limitation or standard and shall submit notification of these
monitoring values in accordance with NPDES permit requirements.
Additionally, the operator shall, as part of the BMP Plan, initiate a
reevaluation and modification to the BMP Plan in conjunction with
equipment vendors and/or industry specialists.

The operator shall include retort monitoring data and dates of
retort-monitored and non-retort-monitored NAF-cuttings discharges
managed by BMPs in their NPDES permit reports.

Establishing mud pit and equipment cleaning methods in such a way as to
minimize the potential for building-up drill cuttings (including
accumulated solids) in the active mud system and solids control
equipment system. These cleaning methods shall include but are not
limited to the following procedures.

Ensuring proper operation and efficiency of mud pit agitation equipment.

Using mud gun lines during mixing operations to provide agitation in
dead spaces.

Pumping drilling fluids off of drill cuttings (including accumulated
solids) for use, recycle, or disposal before using wash water to
dislodge solids.

PAH Content of Oil by HPLC/UV (EPA Method 1654, Revision A)

Scope and Application

This method is designed to determine the polynuclear aromatic
hydrocarbon (PAH) content of oil by high-performance liquid
chromatography (HPLC) with an ultra-violet absorption (UV) detector. The
PAH content is measured and reported as phenanthrene.

This method is for use in the Environmental Protection Agency’s
(EPA’s) survey and monitoring programs under the Federal Water
Pollution Control Act.

For oil in drilling muds, this method is designed to be used in
conjunction with the extraction procedure in EPA Method 1662.

The level of PAH in   REF _Ref238902725 \h  Table 9-1  typifies the
minimum level that can be detected in oil with this method.

Any modification of this method beyond those expressly permitted shall
be considered as a major modification subject to application and
approval of alternative test procedures under 40 CFR 136.4 and 136.5.

This method is restricted to use by or under the supervision of analysts
experienced in the use of HPLC systems and in the interpretation of
liquid chromatograms. Each analyst must demonstrate the ability to
generate acceptable results with this method using the procedure
described in Section   REF _Ref238899892 \r \h  9.8.2 .

Summary of Method

d a 20-μL aliquot is injected into the HPLC. The PAHs are partially
separated by HPLC and detected with the UV detector.

Identification of PAH (qualitative analysis) is performed by comparing
the response of the UV detector to the response during the
retention-time range characteristic of the PAH in diesel oil. PAH is
present when a response occurs during this retention-time range.

Quantitative analysis is performed by calibrating the HPLC with
phenanthrene using an external standard technique, and using the
calibration factor to determine the concentration of PAH in the sample.

Quality is assured through reproducible calibration and testing of the
extraction and HPLC systems.

Interferences

Solvents, reagents, glassware, and other sample processing hardware may
lead to discrete artifacts and/or elevated baselines causing
misinterpretation of chromatograms.

All materials used in the analysis shall be demonstrated to be free from
interferences by running method blanks initially and with each sample
batch (samples started through the extraction process at the same time,
to a maximum of ten). Specific selection of reagents and purification of
solvents by distillation in all-glass systems may be required.

Glassware and, where possible, reagents are cleaned by solvent rinse
and/or baking at 450°C for a minimum of 1 hour.

When used in conjunction with Method 1662, blanks extracted in that
method are treated as an integral part of this method.

Interferences co-extracted from samples may vary from source to source,
depending on the diversity of the site being sampled.

Safety

The toxicity or carcinogenicity of each compound or reagent used in this
method has not been precisely defined; however, each chemical should be
treated as a potential health hazard. Exposure to these chemicals must
be reduced to the lowest possible level.

The laboratory is responsible for maintaining a current awareness file
of OSHA regulations regarding the safe handling of the chemicals
specified in this method. A reference file of material safety data
sheets (MSDSs) should also be made available to all personnel involved
in the chemical analysis. Additional information on laboratory safety
can be found in References 1 through 3.

Methylene chloride has been classified as a known health hazard. All
steps in this method which involve exposure to this compound shall be
per-formed in an OSHA-approved fume hood.

Apparatus and Materials

NOTE: Brand names, suppliers, and part numbers are for illustrative
purposes only. No endorsement is implied. Equivalent performance may be
achieved using apparatus and materials other than those specified here,
but demonstration of equivalent performance meeting the requirements of
this method is the responsibility of the laboratory.

Equipment for glassware cleaning.

Laboratory sink with overhead fume hood.

Kiln: Capable of reaching 450°C within 2 hours and holding 450°C
within ±10°C, with temperature controller and safety switch (Cress
Manufacturing Co, Sante Fe Springs, CA, B31H or X31TS, or equivalent).

Equipment for sample preparation.

Laboratory fume hood.

Analytical balance: Capable of weighing 0.1 mg.

Glassware.

Disposable pipettes: Pasteur, 150 mm long by 5 mm i.d. (Fisher
Scientific 13-678-6A, or equivalent).

Glass pipettes: 1.0- and 10-mL, accurate to 1 % or better.

Volumetric flasks: Glass, 10- and 100-mL.

Sample vials: Amber glass, 2- to 5-mL with PTFE-lined screw-cap, to fit
HPLC autosampler.

High-performance liquid chromatograph (HPLC): An analytical system
complete with pumps, sample injector, column oven, and ultra-violet (UV)
detector.

Pumping system: Capable of isocratic operation and producing a linear
gradient from 50% water/50% acetonitrile to 100% acetonitrile in 10
minutes (Waters 600E, or equivalent).

Sample injector: Capable of automated injection of up to 30 samples
(Waters 700, or equivalent).

Column oven: Capable of operation at room ambient to 50°C (Waters TCM,
or equivalent).

Column: Two C18 columns, 150 mm long by 4.6 mm i.d., 300 angstroms
(Vydac 201 TP5415, or equivalent) connected in series, preceded by one
C18 guard column, 30 mm long by 4.6 mm i.d., 300 angstroms (Vydac 201
GCC54T, or equivalent), operated at the conditions shown in   REF
_Ref238902725 \h  Table 9-1 .

Detector: UV operated at 254 nm (Waters 490E, or equivalent).

Data system.

Data acquisition: The data system shall collect and record LC peak areas
and retention times on magnetic media.

Calibration: The data system shall be used to calculate and maintain
lists of calibration factors (response divided by concentration) and
multi-point calibration curves. Computations of relative standard
deviation (coefficient of variation) are used to test calibration
linearity.

Data processing: The data system shall be used to search, locate,
identify, and quantify the compounds of interest in each analysis.
Displays of chromatograms are required to verify results.

Statistics on initial (Section   REF _Ref238899892 \r \h  9.8.2 ) and
ongoing (Section   REF _Ref238900267 \r \h  9.12.6 ) performance shall
be computed and maintained.

Reagents

Solvents.

Sample preparation: Methylene chloride, distilled in glass (Burdick and
Jackson, or equivalent).

HPLC: Methanol, acetonitrile, and water, HPLC quality.

Standards: Purchased as solutions or mixtures with certification to
their purity, concentration, and authenticity, or prepared from
materials of known purity and composition. If compound purity is 96% or
greater, the weight may be used without correction to compute the
concentration of the standard. If PAH in oil from drilling mud is to be
tested, the diesel oil standard used in this method should be from the
oil used on the drilling rig from which the mud sample is taken. If this
oil is not available, No. 2 diesel oil from a local source may be
substituted.

Stock solutions: Prepare in methylene chloride or methanol and dilute In
acetonitrile for injection into the HPLC. Observe the safety precautions
in Section   REF _Ref238900320 \r \h  9.4 .

Diesel oil solutions

Stock solution in methylene chloride (62.5 mg/mL): If QC extracts from
Method 1662 are to be tested, use the oil that was spiked in that
method. Weigh 6.25 g of diesel oil into a 100-mL ground-glass-stoppered
volumetric flask and fill to the mark with methylene chloride.

Diesel oil calibration solution (1.25 mg/mL): After the oil in the stock
solution (see bullet above) is completely dissolved, remove 1.00 mL and
place in a 50-mL volumetric flask. Dilute to the mark with acetonitrile.
Mix thoroughly and transfer to a clean 150mL bottle with PTFE-lined cap.

Polynuclear aromatic hydrocarbons-naphthalene, phenanthrene, and
indeno[1,2,3-cd]pyrene: Dissolve an appropriate amount of reference
material in a suitable solvent. For example, weigh 10.0 mg of
naphthalene in a 10-mL volumetric flask and fill to the mark with
methanol. After the naphthalene is completely dissolved, transfer the
solution to a 15-mL vial with PTFE-lined cap.

Stock solutions should be checked for signs of degradation prior to the
preparation of calibration or performance test standards.

PAH calibration standards (CAL): Dilute and mix the stock solutions
(Section   REF _Ref238900613 \r \h  <IP_ADDRESS>b ) in acetonitrile to
produce the calibration standards shown in   REF _Ref238900719 \h  Table
9-2 . The three solutions permit the response of phenanthrene to be
measured as a function of concentration, and naphthalene and
indeno[1,2,3-cd]pyrene permit the retention time window for PAH to be
defined. The medium-level solution is used for calibration verification
(Section   REF _Ref238900803 \r \h  9.12.2 ).

Precision and recovery standard: The diesel oil calibration solution
(Section   REF _Ref238900918 \r \h  \* MERGEFORMAT  <IP_ADDRESS>a ), second
bullet) is used for initial precision and recovery (IPR; Section   REF
_Ref238899892 \r \h  \* MERGEFORMAT  9.8.2 ) and ongoing precision and
recovery (OPR, Section   REF _Ref238900267 \r \h  \* MERGEFORMAT  9.12.6
).

Stability of solutions.

When not being used, standards are stored in the dark at -20 to -10°C
in screw-capped vials with PTFE-lined lids. A mark is placed on the vial
at the level of the solution so that solvent loss by evaporation can be
detected. The vial is brought to room temperature prior to use. Any
precipitate is redissolved and solvent is added if solvent loss has
occurred.

Standard solutions used for quantitative purposes (Sections   REF
_Ref238901363 \r \h  \* MERGEFORMAT  <IP_ADDRESS>  through   REF
_Ref238901381 \r \h  \* MERGEFORMAT  <IP_ADDRESS> ) shall be analyzed within
48 hours of preparation and on a monthly basis thereafter for signs of
degradation. Standards will remain
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Inject 20 μL- of the medium level calibration standard (  REF
_Ref238900719 \h  Table 9-2 ).

Locate the three peaks in this standard.

Adjust the initial solvent mixture, the isocratic hold, the gradient,
and the final isocratic hold until the retention times are within + 1
minute of the retention times given in   REF _Ref238900719 \h  Table 9-2
.

Minimum level: Analyze 20 μL of the low-level calibration standard (
REF _Ref238900719 \h  Table 9-2 ) and verify that the HPLC instrument
meets the minimum level for phenanthrene in   REF _Ref238902725 \h
Table 9-1 .

External standard calibration.

Analyze 20 μL of each calibration standard (  REF _Ref238900719 \h
Table 9-2 ) beginning with the lowest concentration and proceeding to
the highest using to the procedure in Section   REF _Ref238901537 \r \h
9.11 .

Record the areas for the phenanthrene peak and the height of the
phenanthrene peak in the high-level standard.

Compute the ratio of response to amount injected (calibration factor) at
each concentration by dividing the area of the peak by the concentration
of the standard injected. Calculate the mean of the three values to
produce an average calibration factor.

Linearity: If the calibration factor is constant over the three point
calibration range (< 15% relative standard deviation), linearity through
the origin can be assumed; if not, the system shall be recalibrated.

The average calibration factor is verified on each working 8-hour shift
by the measurement of the medium-level calibration standard (Section
REF _Ref238901565 \r \h  \* MERGEFORMAT  9.12.5 ).

Single-point calibration for diesel oil: Inject the precision and
recovery standard (Section   REF _Ref238901381 \r \h  \* MERGEFORMAT
<IP_ADDRESS> ) to produce a single calibration point for diesel oil.

Integrate the area from the retention time of naphthalene (including the
leading edge of the naphthalene peak) through the end of the
indeno[1,2,3-cd]pyrene peak or until the detector signal returns to a
stable baseline, whichever comes later, as shown in   REF _Ref238901607
\h  Figure 9-1 .

Determine the calibration factor for diesel oil by dividing the
integrated area (  REF _Ref238901636 \r \h  <IP_ADDRESS> ) by the diesel oil
concentration (Section   REF _Ref238900918 \r \h  \* MERGEFORMAT
<IP_ADDRESS>a ), second bullet).

Quality Assurance/Quality Control

Each laboratory that uses this method is required to operate a formal
quality assurance program (Reference 4). The minimum requirements of
this program consist of an initial demonstration of laboratory
capability, an ongoing analysis of standards and blanks as a test of
continued performance, analyses of spiked samples to assess accuracy,
and analysis of duplicates to assess precision. Laboratory performance
is compared to established performance criteria to determine if the
results of analyses meet the performance characteristics of the method.
If the determination of PAH is to be made on extracts from Method 1662,
the quality control samples for initial precision and recovery (IPR),
spiked samples, duplicate samples, and ongoing precision and recovery
(OPR) samples from Method 1662 shall be substituted for those in the QC
tests below, and the specifications in   REF _Ref238902725 \h  Table 9-1
 for extracts from Method 1662 shall be met.

The analyst shall make an initial demonstration of the ability to
generate acceptable accuracy and precision with this method. This
ability is established as described in Section   REF _Ref238899892 \r \h
 9.8.2 .

The analyst is permitted to modify this method to improve separations or
lower the costs of measurements, provided all performance requirements
are met. Each time a modification is made to the method, the analyst is
required to achieve the minimum level (Section   REF _Ref238902775 \r \h
 9.7.3 ) and to repeat the procedure in Section   REF _Ref238899892 \r
\h  9.8.2  to demonstrate method performance.

Analyses of spiked samples are required to demonstrate method accuracy
when extracts from Method 1662 are analyzed. The procedure and QC
criteria for spiking are described in Section   REF _Ref238902806 \r \h
9.8.3 .

Analyses of duplicate samples are required to demonstrate method
precision when extracts from Method 1662 are analyzed. The procedure and
QC criteria for duplicates are described in   REF _Ref238902823 \r \h
9.8.4 .

Analyses of blanks are required to demonstrate freedom from
contamination. The procedures and criteria for analysis of a blank are
described in Section   REF _Ref238902861 \r \h  9.8.5 .

The laboratory shall, on an ongoing basis, demonstrate through
calibration verification and analysis of the precision and recovery
standard that the analysis system is in control. These procedures are
described in Sections   REF _Ref238901565 \r \h  \* MERGEFORMAT  9.12.5
and   REF _Ref238900267 \r \h  \* MERGEFORMAT  9.12.6 .

The laboratory shall maintain records to define the quality of data that
is generated. Development of accuracy statements is described in
Sections   REF _Ref238905855 \r \h  <IP_ADDRESS>  and   REF _Ref238905867 \r
\h  <IP_ADDRESS> .

Initial precision and recovery (IPR): The initial precision and recovery
test is performed using the precision and recovery standard. If extracts
from Method 1662 are to be analyzed, the extracts from the initial
precision and recovery tests in that method shall be used; otherwise,
the laboratory shall generate acceptable precision and recovery by
performing the following operations.

Using diesel oil, prepare four separate aliquots of the precision and
recovery standard (Section   REF _Ref238901381 \r \h  <IP_ADDRESS> ). If
extracts from Method 1662 are analyzed, the extracts from the initial
precision and recovery test in that method shall be used. Analyze these
aliquots using the procedure in Section   REF _Ref238905895 \r \h  9.11
.

Using results of the set of four analyses, compute the average recovery
(X) of PAH in mg/mL and the standard deviation of the recovery (s) in
mg/mL for each aliquot by the external standard method (Sections   REF
_Ref238905919 \r \h  \* MERGEFORMAT  9.7.4  and   REF _Ref238905932 \r
\h  \* MERGEFORMAT  9.14.4 ).

Compare s and X with the corresponding limits for initial precision and
recovery in   REF _Ref238902725 \h  Table 9-1 . If s and X meet the
acceptance criteria, system performance is acceptable and analysis of
oil samples may begin. If, however, s exceeds the precision limit or X
falls outside the range for accuracy, system performance is
unacceptable. In this event, review this method, correct the problem,
and repeat the test.

Method accuracy: If extracts from Method 1662 are to be analyzed, the
extract from the accuracy test in that method shall be used; otherwise,
an accuracy test is unnecessary. The procedure for determining method
accuracy is given in Section 8.3 of Method 1662, and the specification
for accuracy is given in   REF _Ref238902725 \h  Table 9-1  of this
method.

Compare the percent recovery of PAH with the corresponding QC acceptance
criteria in   REF _Ref238902725 \h  Table 9-1 . If the results of the
spike fail the acceptance criteria, and the recovery of the QC standard
in the ongoing precision and recovery test (Section   REF _Ref238906537
\r \h  <IP_ADDRESS> ) is within the acceptance criteria in   REF
_Ref238902725 \h  Table 9-1 , an interference may be present. In this
case, the result may not be reported for regulatory compliance purposes.
If, however, the results of both the spike and the ongoing precision and
recovery test fail the acceptance criteria, the analytical system is
judged to be out of control and the problem shall be identified and
corrected, and the sample batch reanalyzed.

As part of the QA program for the laboratory, method accuracy for
samples shall be assessed and records shall be maintained. After the
analysis of five spiked samples in which the recovery passes the test in
Section   REF _Ref238902806 \r \h  9.8.3 , compute the average percent
recovery (P) and the standard deviation of the percent recovery (P).
Express the accuracy assessment as a percent recovery interval from P
– 2Sp to P + 2 Sp. For example, if P = 90% and Sp = 10% for five
analyses of PAH in diesel oil, the accuracy interval is expressed as 70
to 110%. Update the accuracy assessment on a regular basis (e.g., after
each five to ten new accuracy measurements).

Duplicates: If extracts from Method 1662 are to be analyzed, the
extracts from the duplicates test in that method shall be used. The
procedure for preparing duplicates is given in Section 8.4 of Method
1662, and the specification for RPD is given in   REF _Ref238902725 \h
\* MERGEFORMAT  Table 9-1  of this method. If extracts from Method 1662
are not to be analyzed, duplicates of the precision and recovery
standard (Section   REF _Ref238901381 \r \h  <IP_ADDRESS> ) are analyzed, and
the specification for RPD is given for PAH in diesel oil in   REF
_Ref238902725 \h  Table 9-1  of this method.

Analyze each of the duplicates per the procedure in Section   REF
_Ref238906598 \r \h  9.11  and compute the results per Section   REF
_Ref238906610 \r \h  9.14 .

Calculate the relative percent difference (RPD) between the two results
per the following equation:

 	[  STYLEREF 1 \s  9 -  SEQ Equation \* ARABIC \s 1  1 ]

Where:

D1	=	Concentration of diesel oil in the sample

D2	=	Concentration of diesel oil in the second (duplicate) sample

The relative percent difference for duplicates shall meet the acceptance
criteria in   REF _Ref238902725 \h  Table 9-1 . If the criteria are not
met, the analytical system is be judged to be out of control, and the
problem must be immediately identified and corrected and the sample set
re-extracted and reanalyzed.

Blanks: If extracts from Method 1662 are to be analyzed, the extracts
from blanks in that method shall be analyzed in addition to the blanks
in this method.

Rinse the glassware used in preparation of the extracts in this method
with acetonitrile and analyze a 20-μL aliquot of the rinsate using the
procedure in Section   REF _Ref238906628 \r \h  9.11  and compute the
results per Section   REF _Ref238906639 \r \h  9.14 .

If PAH is detected in a blank at greater than the method detection limit
(MDL) in   REF _Ref238902725 \h  Table 9-1 , analysis of samples is
halted until the source of contamination is eliminated and a blank shows
no evidence of contamination.

The specifications contained in this method can be met if the apparatus
used is calibrated properly, then maintained in a calibrated state. The
standards used for initial precision and recovery (IPR, Section   REF
_Ref238899892 \r \h  9.8.2 ) and ongoing precision and recovery (OPR,
Section   REF _Ref238900267 \r \h  9.12.6 ) should be identical, so that
the most precise results will be obtained. The HPLC instrument will
provide the most reproducible results if dedicated to the settings and
conditions required for the analyses given in this method.

Depending on specific program requirements, field replicates and field
spikes of diesel oil into samples may be required when Method 1662 and
this method are used to assess the precision and accuracy of the
sampling and sample transportation techniques.

Sample Collection, Preservation, and Handling

Oil samples are collected in 20- to 40-mL vials with PTFE- or
aluminum-foil-lined caps and stored in the dark at -20 to -10°C.

If extracts from Method 1662 are to be analyzed, the laboratory should
be aware that sample and extract holding times for this method have not
yet been established. However, based on tests of wastewater for the
analytes determined in this method, samples shall be extracted within 7
days of collection and extracts shall be analyzed within 40 days of
extraction.

As a precaution against analyte and solvent loss or degradation, sample
extracts are stored in glass bottles with PTFE-lined caps, in the dark,
at -20 to -10°C.

Dilution of Oil and Extracts

000 μg/mL. Mineral oils and other oils containing a lesser PAH content
will require less dilution.

Extracts from Method 1662: If extracts of samples from Method 1662 are
to be analyzed, these extracts (from Section 10.4.2 of that method) are
analyzed undiluted unless diesel oil is known or suspected to be
present. Extracts of QC samples (IPR, OPR, matrix spikes, and
duplicates) from Method 1662 are diluted by a factor of 10 to bring them
within the range of the HPLC.

Dilution of neat oil expected to be diesel oil.

Weigh 100 mg into a 10-mL volumetric flask and dilute to the mark with
methylene chloride to produce a concentration of 10 mg/mL. Stopper and
mix thoroughly.

Using a calibrated 1.0-mL volumetric pipette, withdraw 1.0 mL of the
solution and place in a 10-mL volumetric flask. Then withdraw an
additional 0.25 mL of the solution and place in the 10-mL volumetric
flask (for a total of 1.25 mL). Fill to the mark with acetonitrile to
produce a concentration of 1.25 mg/mL (1250 μg/mL). This solution will
be near, but not above, the limit of the calibration range and will
match the concentration of the QC samples from Method 1662 (assuming
100% recovery).

High-Performance Liquid Chromatography

  REF _Ref238900719 \h  Table 9-2  summarizes the recommended operating
conditions for the HPLC. Included in this table and in   REF
_Ref238902725 \h  Table 9-1  are retention times and the minimum level
that can be achieved under these conditions. An example of the
separation achieved for diesel oil by the multiple HPLC column system is
shown in   REF _Ref238901607 \h  Figure 9-1 . Other HPLC columns,
chromatographic conditions, or detectors may be used if the requirements
for the minimum level (Section   REF _Ref238902775 \r \h  9.7.3 ) and
initial precision and
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Inject 20 μL of the sample extract, Method 1662 extract, or diluted QC
extract into the HPLC using a high-pressure syringe or a constant-volume
sample-injection loop. Record the volume injected to the nearest 0.1
μL.

Upon injection, begin the solvent program used in calibrating the column
(Section   REF _Ref238906903 \r \h  <IP_ADDRESS> ). Record the signal from
the time of injection until the detector returns to a stable baseline.
Return the solvent to the initial conditions.

Using the retention-time data determined during calibration, integrate
the area from the retention time of naphthalene (including the leading
edge of the naphthalene peak) through the end of the
indeno[1,2,3-cd]pyrene peak or until the detector signal returns to a
stable baseline, whichever comes later.

If the height of the response during the period recorded (Section   REF
_Ref238906924 \r \h  <IP_ADDRESS> ) exceeds the height of the response for
phenanthrene during calibration (Section   REF _Ref238906939 \r \h
<IP_ADDRESS> ), dilute the extract by successive factors of 10 with
acetonitrile and reanalyze until the response is within the calibration
range.

HPLC System and Laboratory Performance

At the beginning of each 8-hour shift during which analyses are
performed, HPLC calibration and system performance are verified. For
these tests, analysis of the medium level calibration standard (  REF
_Ref238900719 \h  Table 9-2 ) and of the diluted extract of the
precision and recovery standard (Section   REF _Ref238901381 \r \h
<IP_ADDRESS> ) shall be used to verify all performance criteria. Adjustment
and/or recalibration (per Section   REF _Ref238906969 \r \h  9.7 ) shall
be performed until all performance criteria are met. Only after all
performance criteria are met may samples and blanks be analyzed.

Inject 20 μL of the medium-level calibration standard (  REF
_Ref238900719 \h  Table 9-2 ) into the HPLC instrument according to the
procedure in Section   REF _Ref238907025 \r \h  9.11 .

Retention time: The absolute retention times of the naphthalene,
phenanthrene, and indeno[1,2,3-cd]pyrene peaks shall be within ±30
seconds of the respective retention times in the initial calibration
(Section   REF _Ref238906903 \r \h  <IP_ADDRESS> ).

HPLC resolution: Resolution is acceptable if the peak width at
half-height of the phenanthrene peak is less than 30 seconds.

Calibration verification: Compute the concentration of phenanthrene
based on the average calibration factor (Section   REF _Ref238907052 \r
\h  <IP_ADDRESS> ). The concentration shall be within the limits in   REF
_Ref238902725 \h  Table 9-1 . If calibration is verified, system
performance is acceptable and analysis of blanks and QC samples may
begin. If, however, the concentration falls outside of the calibration
verification range, system performance is unacceptable. In this case,
correct the problem and repeat the test, or recalibrate (Section   REF
_Ref238905919 \r \h  9.7.4 ).

Ongoing precision and recovery (OPR): If the extract is from Method
1662, the OPR standard from that method shall be used and the
specification for the OPR from Method 1662 in   REF _Ref238902725 \h
Table 9-1  shall be met; if not, a sample of diesel oil shall be diluted
per the procedure in Section   REF _Ref238907090 \r \h  9.10  and shall
be used for the OPR test.

Analyze the appropriate OPR standard.

Compute the concentration of PAH in this standard per Section   REF
_Ref238907100 \r \h  9.14 .

Compare the concentration with the limits for ongoing precision and
recovery in   REF _Ref238902725 \h  Table 9-1 . If the concentration is
in the range specified, the analytical processes are in control and
analysis of blanks and samples may proceed. If, however, the
concentration is not in the specified range, these processes are not in
control. In this event, correct the problem, re-extract the sample batch
if the OPR is from Method 1662, or redilute the oil sample (per Section
 REF _Ref238907127 \r \h  9.10.3 ). and repeat the ongoing precision and
recovery test.

Add results which pass the specification in Section   REF _Ref238906537
\r \h  <IP_ADDRESS>  to initial and previous ongoing data. Update QC charts
to form a graphic representation of continued laboratory performance.
Develop a statement of laboratory data quality for each analyte by
calculating the average percent recovery (R) and the standard deviation
of percent recovery (Sr). Express the accuracy as a recovery interval
from R – 2Sr, to R + 2 Sr. For example, if R = 95% and Sr = 5%, the
accuracy is 85 to 105%.

Qualitative Identification

Qualitative determination is accomplished by comparison of data from
analysis of a sample or blank with data from analysis of the calibration
verification standard (Section   REF _Ref238901565 \r \h  9.12.5 ).

PAH is identified in the sample by the presence of peaks and/or an
elevated baseline (hump) between the retention times of the naphthalene
and indeno[1,2,3-cd]pyrene peaks (Section   REF _Ref238907351 \r \h
<IP_ADDRESS> ), as shown in   REF _Ref238901607 \h  Figure 9-1 . The
experience of the analyst shall weigh heavily in interpretation of the
chromatogram.

Quantitative Determination

Using the data system, compute the concentration of the PAH detected in
the solution injected into the HPLC (in μg/mL) using the calibration
factor (Section   REF _Ref238905919 \r \h  9.7.4 ).

Concentration of PAH in oil: If neat oil was analyzed, the concentration
of PAH in the oil is determined using the following equation:

 	[  STYLEREF 1 \s  9 -  SEQ Equation \* ARABIC \s 1  2 ]

Where:

Co 	=	Concentration of PAH in the oil sample

Cp 	= 	Concentration of PAH measured (from Sections   REF _Ref238907387
\r \h  9.11.4  and   REF _Ref238907401 \r \h  9.14.1 )

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Concentration of diesel oil in QC extracts from Method 1662: Calculate
the concentration of diesel oil in QC extracts from Method 1662 by
integrating the area per Section   REF _Ref238901636 \r \h  <IP_ADDRESS>  and
using the calibration from Section   REF _Ref238907484 \r \h  <IP_ADDRESS>
of this method, taking into account the dilution of these extracts
(Section   REF _Ref238907498 \r \h  9.10.2 ).

Concentration of PAH in oil from Method 1662: The PAH content of oil is
complicated by the splitting and possible dilution of these extracts.

Concentration in undiluted extracts: This concentration is determined by
Equation 9-3:

   SHAPE  \* MERGEFORMAT   	[  STYLEREF 1 \s  9 -  SEQ Equation \*
ARABIC \s 1  3 ]

Where:

Co 	= 	Concentration of PAH in the oil sample

Ve 	= 	Amount of extract split for HPLC analysis, in mL (1.0 mL)

Cp 	= 	Concentration of PAH measured

WT 	= 	Weight of oil in the concentration tube in Method 1662 (Section
11.5.5 of Method 1662)

1/5 	= 	Fraction of this weight used for the PAH determination

Concentration in diluted extracts: If the extract was diluted by a
factor of 10 (Section   REF _Ref238907127 \r \h  9.10.3  or   REF
_Ref238907387 \r \h  9.11.4 ), the concentration determined in Section
REF _Ref238907541 \r \h  <IP_ADDRESS>  is multiplied by 10.

If the concentration is to be expressed as weight percent, Co is
multiplied by 0.1.

Report results to three significant figures without correction for
recovery.

Method Performance

This method was validated in a single laboratory (Reference 6) using
samples of hot-rolled drilling mud (Reference 7).

References

“Carcinogens-Working With Carcinogens.” Department of Health,
Education, and Welfare, Public Health Service, Centers for Disease
Control [available through National Technical Information System, 5285
Port Royal Road, Springfield, VA 22161, document no. PB2772561: August
1977.

“OSHA Safety and Health Standards, General Industry [29 CFR 1910],
Revised.” Occupational Safety and Health Administration, OSHA 2206.
Washington, DC: January 1976.

“Safety in Academic Chemistry Laboratories (3rd Edition).” American
Chemical Society Publication, Committee on Chemical Safety. Washington,
DC: 1979.

“Handbook of Analytical Quality Control in Water and Wastewater
Laboratories.” USEPA, EMSL-Ci, EPA-600/4-79-019. Cincinnati, OH: March
1979.

“Standard Practice for Sampling Water,” ASTM Annual Book of
Standards, Part 31, D337076, ASTM. Philadelphia, PA: 1980.

“Determination of Polynuclear Aromatic Hydrocarbons and Diesel by
Modified EPA Method 9310.” Prepared for the American Petroleum
Institute c/o Shell Development Co, Westhollow Research Center, 3333
Highway 6 South, Houston, TX 77082 by Analytical Technologies Inc., 225
Commerce Drive, Fort Collins, CO 80524: March 29 1991, April 12, 1991,
and August 18, 1992.

“Results of the API Study of Extraction and Analysis Procedures for
the Determination of Diesel Oil in Drilling Muds (Final Report).”
American Petroleum Institute, Offshore Effluent Guidelines Steering
Committee, Technology Work Group, Prepared by I.C. Raia, Shell
Development Co. Houston, TX: April 18, 1991.

Table   STYLEREF 1 \s  9 -  SEQ Table \* ARABIC \s 1  1 . Performance
Data and Method Acceptance Criteria for PAH

μg/mL	100	—	0.1

Method Detection Limit d	μg/mg	7.6	—	—

Initial prec and recov

Precision (std dev)

PAH in diesel oil e	mg/mL	120	—	—

Diesel in mud extract f	mg/mL	—	0.55	—

Recovery

PAH in diesel oil e	mg/mL	1,090 – 1,340	—	—

Diesel in mud extract f	mg/mL	—	0.84 – 1.95	—

Calibration verification g	μg/mL	—	—	0.39 – 0.61

Ongoing prec and recov

PAH in diesel oil e	mg/mL	1,010 – 1,450	—	—

Diesel in mud extract f	mg/mL	—	0.76 – 2.15	—

Matrix spike recovery f	pct	—	0.43 – 2.39	—

Duplicates	RPD	9.5	44	—

a CAS Registry number 68534-30-5; No. 2 diesel oil used for these tests.

b From Method 1662.

c This is a minimum level at which the analytical system shall give
recognizable signals and acceptable calibration points..

d 40 CFR Part 136, Appendix B; MDL is measured as PAH in oil.

μg/mL.

f Test concentration in diluted extract = 1.25 mg/mL.

g Test concentration = 0.50 μg/mL.

Table   STYLEREF 1 \s  9 -  SEQ Table \* ARABIC \s 1  2 . HPLC
Calibration Data

Analyte	Retention Time a

(minutes)	Calibration Solution Concentration (μg/mL)

Low	Medium	High

Naphthalene	7.6	—	5	—

Phenanthrene	10.3	0.1	0.5	2.0

Indeno[l23-cd]pyrene	18.9	—	0.5	—

Diesel oil b	7.4 – 20.0	100	400	2,000

a Column system: Two C18 columns (150 mm long by 4.6 mm i.d., 300
angstroms) connected in series,

preceded by one C18 guard column (30 mm long by 4.6 mm i.d., 300
angstroms). Column temperature 30°C;

solvent flow rate 1.5 mL/min; linear gradient from 50% water/50%
acetonitrile at injection to 100%

acetonitrile in 10 minutes, hold at 100% acetonitrile for 15 minutes.

b Diesel oil is calibrated separately using a single point calibration
(Section   REF _Ref239495932 \r \h  9.7.6 ).

Figure   STYLEREF 1 \s  9 -  SEQ Figure \* ARABIC \s 1  1 . Liquid
Chromatography of the Three-Component Standard and of No. 2 Diesel Oil

 PAGE

CONTENTS (Continued)

Page

 PAGE   iii

 PAGE   i

LIST OF TABLES (Continued)

Page

 PAGE   iii

 PAGE   iv

LIST OF FIGURES (Continued)

Page

 PAGE   iv

 PAGE   v

 PAGE   1-9

 PAGE   9-15

2,000 mg carbon	×	240 g	= 480 mg carbon

Per kg dry sediment

1,000

Conc. Desired (mg/kg)	×	Dry Weight Sediment (kg)	=	Base Fluid Required
(mg)

g wet sediment	= mL wet sediment

Density (g/mL) of wet sediment

Volume sea water per bottle (Eq. 5-9)	= Ratio of sea water:wet sediment

Volume sediment water per bottle (Eq. 5-8)

Mean Wet Sediment Weight (g)	= Wet Sediment Density (g/mL)

Mean Wet Sediment Volume (mL)

Mean Wet Sediment Weight (g)	= Wet to Dry Ratio

Mean Dry Sediment Weight (g)

Conc. Desired (mL/kg)	×	Dry Weight Sediment (kg)	×	Test Substance
Density (g/mL)	=	Test Substance Required (g)

Wet Sediment per Concentration (g)	×	1 kg	= Dry Weight Sediment (kg)

Mean Wet to Dry Ratio

1,000 g

Wet Sediment Density (g/mL)	×	Volume of Sediment Required per
Concentration (mL)	=	Weight Wet Sediment Required per Conc. (g)

Mean Wet Sediment Weight (g)	= Wet Sediment Density (g/mL)

Mean Wet Sediment Volume (mL)

Wet Sediment Weight (g)	= Wet to Dry Ratio

Dry Sediment Weight (g)

 Integrate peaks on the EIP for comparison to calibration to determine
approximate crude oil contamination

Section <IP_ADDRESS>

Peaks present for Target Aromatics on EIP

 Crude oil contamination is below detection limit.

Report not detected

Section <IP_ADDRESS>

 Determine the C8 to C13 TIC Area for comparison to calibration
standards

Section <IP_ADDRESS>

 Obtain the EIP for

m/z 91, m/z 105, and m/z 156

Section <IP_ADDRESS>

C8 to C13 peaks seen on TIC

GC/MS Analyses

Obtain the TIC for the Sample

Section 6.11.2

Vwell (barrels) = Σ	Bit diameter (in)2	 × change in measured depth
(ft)

	1,029

XSVD =	FSVD

	Gwell+ FSVD

Prepare Sample for Analyses

Section 6.11.1

Xi = 	Fi

	G

%BFi =	MBF	 × 100

	Mw

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Mw

RPD =	D1 – D2	× 100

	(D1 – D2) ÷ 2

Co =	Ve × Cp	=	5 × I Cp

	1/5 × WT

WT

Co (mg/g) =	Cp (μg/mL)

	Ci (mg/mL)

RPD =	D1 – D2	 × 100

	(D1 + D2) ÷ 2

12 mole CH4	×	22.4 L	×	1,000 ml	×	1 mole hexadecene	×	23 g
hexadecene	×	0.03 kg	= 84 (ml)

mole hexadecene

mole CH4

L

224.4 g hexadecene

kg dry soil

culture

VCH4 (ml) =	(S + V) ×	P – Pw	×	CH4	×	273

T + 273

100

760

Corrected % CH1 =	% CH4

	1 –	D × 22.4 L/mol

18 g/mol × 1,000

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% Theoretical gas production of NAF

60 mg carbon per bottle/1,000	= 0.005 moles carbon

12 g/mole

V2 =	P1 × V1 × T2

	T1 × P2

mL wet sediment (Eq. 5-11)	×	Sea water:sediment ratio (Eq. 5-10)	=	mL
sea water to add to wet sediment

480 mg carbon	= 621 mg ethyl oleate

(77.3 ÷ 100)