# Analy**tic Methods for the Oil and Gas**

**Extraction Point Source Category**

**U.S. Env ironmental Protection A**  **gency**

Engineering and Analysis Division

Office of W ater 1200 Pennsylvania Avenue, N W Wa shington, D.C. 20460

December 2011 EPA - 821 - R - 11 - 004**CONTENTS (Continued)**  **CONTENTS Page**  1. S UMMARY OF M ETHODS ................................ ................................ ................................ ... 1 - 1 1.1 Static Sheen Test (EPA Method 1617) ................................ ................................ 1 - 5 1.2 Drilling Fluids Toxicity Test (EPA Method 1619) ................................ .............. 1 - 5 1.3 Procedure for Mixing Base Fluids with Sediments (EPA Method 1646) ............ 1 - 5 1.4 Protocol for the Determination of Degradation of Non - Aqueous Base Fluids in a Marine Closed Bottle Biodegradation Test Sy stem: Modified ISO 11734:1995 (EPA Method 1647) ................................ ................................ . 1 - 6 1.5 Determination of Crude Oil Contamination in Non - Aqueous Drilling Fluids by Gas Chromatography

/Mass Spectrometry

(GC/MS) (EPA Method 1655) ................................ ................................ ................................ ....... 1 - 7 1.6 Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non - Aqueous Drilling Fluids (NAF) (EPA Method 1670) ................................ ................................ ................................ .................... 1 - 7 1.7 Determination of the Amount Of Non - Aqueous Drilling Fluid (NAF) Base Fluid from Dri ll Cuttings by a Retort Chamber (Derived From API Recommended Practice 13B

–2) (EPA Method 1674) ................................ ......... 1 - 8 1.8 PAH Content of Oil by HPL C/UV (EPA Method 1654, Revision A) ................. 1 - 8 1.9 Sediment Toxicity Test for NAF and SBM (EPA Method 1644) ....................... 1 - 8 1.10 Previous Publication of Oil and Gas Extraction Point Source Category Analy tic Meth ods ................................ ................................ ................................ . 1 - 9 2. S TA TIC S HEEN T EST (EPA M ETHOD 1617) ................................ ................................ ..... 2 - 11 2.1 Scope and Application ................................ ................................ ....................... 2 - 11 2.2 Summary

of Method ................................ ................................ .......................... 2 - 11 2.3 Interferences ................................ ................................ ................................ ....... 2 - 11 2.4 Apparatus, Materials, and Reagents ................................ ................................ ... 2 - 11 2.5 Calibration ................................ ................................ ................................ .......... 2 - 12 2.6 Quality

Control Procedures ................................ ................................ ................ 2 - 12 2.7 Sample Collection and Handling ................................ ................................ ....... 2 - 12 2.8 Procedure ................................ ................................ ................................ ........... 2 - 13 3. D RILLING F LUIDS T OXI CITY T EST (EPA M ETHOD 1619) ................................ .................. 3 - 1 3.1 Scope and Application ................................ ................................ ......................... 3 - 1 3.2 Summary

of Method ................................ ................................ ............................ 3 - 1 3.3 Sample Collection ................................ ................................ ................................ 3 - 1 3.4 Suspended Particulate Phase Sample Preparation ................................ ............... 3 - 2 3.5 Guidance for Performing Suspended Particulate Phase Toxicity Tests Using M ys idopsis bah ia ................................ ................................ ....................... 3 - 4 3.6 Methods for Positive Control Tests (Reference Toxicant) ................................ .. 3 - 7 3.7 Randomization Procedure ................................ ................................ .................... 3 - 7 3.8 References ................................ ................................ ................................ .......... 3 - 12 4. P ROCEDURE F OR M IX ING B ASE F LU IDS W ITH S EDIMENTS (EPA M ETHOD 1646) ............ 4 - 1 4.1 Determining the Wet to Dry Ratio for the Control Sediment .............................. 4 - 1 4.2 Determining the Density of the Wet Control or Dilution Sediment .................... 4 - 1 4.3 Determining the Amount of Base Fluid Needed ................................ .................. 4 - 1 4.4 Primary

Mixing ................................ ................................ ................................ .... 4 - 24.5 Testing for Homogeneity of Base Fluid ................................ ............................... 4 - 2

4.6 Commencing the Sediment Toxicity Test ................................ ............................ 4 - 2 4.7 References ................................ ................................ ................................ ............ 4 - 3 5. P ROTOCOL FOR THE D ETERMINATION OF D EGRADATION OF N ON - A QUEOUS B ASE F LU IDS IN A M ARINE C LOSED B OTTLE B IODEGRADATION T EST S YSTEM : M ODIFIED ISO 11734:1995 (EPA M ETHOD 1647) ................................ ................................ ............ 5 - 1 5.1 Summ ary

of Method ................................ ................................ ............................ 5 - 1 5.2 Sy stem Requirements ................................ ................................ ........................... 5 - 1 5.3 Test Set Up ................................ ................................ ................................ ........... 5 - 2 5.4 Concentration Verification Chemical Anal ys es ................................ ................... 5 - 6 5.5 Gas Monitoring Procedures ................................ ................................ ................. 5 - 7 5.6 Test Acceptability and Interpretati on ................................ ................................ ... 5 - 9 5.7 Methane Measurement ................................ ................................ ......................... 5 - 9 5.8 Concentration Verification Analy sis ................................ ................................ .. 5 - 11 5.9 Program Quality

Assurance and Quality

Control ................................ .............. 5 - 12 6. D ETERMINATION OF C RUDE O IL C ONTAMINATION IN N ON - A QUEOUS D RILLING F LU IDS BY GAS C HROMATOGRAPHY/M ASS S PECTROMETRY (GC/MS ) (EPA M ETHOD 1655) ................................ ................................ ................................ ................. 6 - 1 6.1 Scope and Application ................................ ................................ ......................... 6 - 1 6.2 Summary

of Method ................................ ................................ ............................ 6 - 1 6.3 Definitions ................................ ................................ ................................ ............ 6 - 2 6.4 Interferences and Limitations ................................ ................................ .............. 6 - 2 6.5 Safety ................................ ................................ ................................ ................... 6 - 2 6.6 Apparatus and Materials ................................ ................................ ...................... 6 - 3 6.7 Reagents and Standards ................................ ................................ ....................... 6 - 4 6.8 Sample Collection Preservation and S torage ................................ ....................... 6 - 6 6.9 Quality

Control ................................ ................................ ................................ .... 6 - 6 6.10 Calibration ................................ ................................ ................................ ............ 6 - 9 6.11 Pro cedure ................................ ................................ ................................ ........... 6 - 11 6.12 Calculations ................................ ................................ ................................ ........ 6 - 15 6.13 Method Performance ................................ ................................ .......................... 6 - 16 6.14 Pollution Prevention ................................ ................................ ........................... 6 - 16 6.15 Waste Management ................................ ................................ ............................ 6 - 16 6.16 References ................................ ................................ ................................ .......... 6 - 17 6.17 Schematic Flowchart for Qualitative Identification ................................ ........... 6 - 18 7. REVERSE P HASE E XTRACTION (RPE) M ETHOD FOR D ETECTION OF O IL C ONTAMINATION IN N ON - A QUEOUS D RILLING F LU IDS (NAF) (EP A M ETHOD 1670) ...... 7 - 1 7.1 Scope and Application ................................ ................................ ......................... 7 - 1 7.2 Summary

of Method ................................ ................................ ............................ 7 - 1 7.3 Definitions ................................ ................................ ................................ ............ 7 - 1 7.4 Interferences ................................ ................................ ................................ ......... 7 - 2 7.5 Safety ................................ ................................ ................................ ................... 7 - 2 7.6 Equipment and Supplies ................................ ................................ ...................... 7 - 2 7.7 Reagents and Standards ................................ ................................ ....................... 7 - 4 7.8 Sample Collection, Preservation, and Storage ................................ ..................... 7 - 4 7.9 Quality

Control ................................ ................................ ................................ .... 7 - 47.10 Calibration and Standardization ................................ ................................ ........... 7 - 7

7.11 Pro cedure ................................ ................................ ................................ ............. 7 - 7 7.12 Data Anal ys is and Calculations ................................ ................................ ........... 7 - 9 7.13 Method Performance ................................ ................................ ............................ 7 - 9 7.14 Pollution Prevention ................................ ................................ ............................. 7 - 9 7.15 Waste Management ................................ ................................ ............................ 7 - 10 7.16 References ................................ ................................ ................................ .......... 7 - 10 8. D ETERMINATION OF THE AMOUNT O F N ON - A QUEOUS D RILLING F LUID (NAF) B ASE F LU ID F ROM D RILL C UTTINGS BY A RETORT C HAMBER (D ERIVED F ROM API RECOMMENDED P RACTICE 13B

–2) (EPA M ETHOD 1674) ................................ ................ 8 - 1 8.1 Description ................................ ................................ ................................ ........... 8 - 1 8.2 Equipment ................................ ................................ ................................ ............ 8 - 1 8.3 Procedure ................................ ................................ ................................ ............. 8 - 2 8.4 Calculations ................................ ................................ ................................ .......... 8 - 3 8.5 Requirements for Sampling Cuttings Discharge Streams for use with this Method ................................ ................................ ................................ ................. 8 - 9 8.6 Be st Management Practices (BMPs) for use with this Method ......................... 8 - 12 9. PAH C ONTENT OF O IL BY HPL C/UV (EPA M ETHOD 1654, REVISION A) ....................... 9 - 1 9.1 Scope and Application ................................ ................................ ......................... 9 - 1 9.2 Summary

of Method ................................ ................................ ............................ 9 - 1 9.3 Interferences ................................ ................................ ................................ ......... 9 - 1 9.4 Safety ................................ ................................ ................................ ................... 9 - 2 9.5 Apparatus and Materials ................................ ................................ ...................... 9 - 2 9.6 Reagents ................................ ................................ ................................ ............... 9 - 4 9.7 Calibration ................................ ................................ ................................ ............ 9 - 5 9.8 Quality

Assurance/Quality

Control ................................ ................................ ...... 9 - 6 9.9 Sample Collection, Preservation, and Handling ................................ .................. 9 - 9 9.10 Dilution of Oil and Extracts ................................ ................................ ................. 9 - 9 9.11 High - Performance Liquid Chromatography ................................ ...................... 9 - 10 9.12 HPL C Sy stem and Laboratory Performance ................................ ...................... 9 - 11 9.13 Qualitative Identification ................................ ................................ ................... 9 - 12 9.14 Quantitative Determination ................................ ................................ ................ 9 - 12 9.15 Method Performance ................................ ................................ .......................... 9 - 13 9.16 References ................................ ................................ ................................ .......... 9 - 13 10. M ETHOD FOR C ONDUCTING A S EDIMENT T OXICITY T EST WITH LEPTOCHEIRUS PLUMULOSUS AND N ON - A QUEOUS D RILLING F LUIDS OR S YNTHETIC - BASED D RILLING M UDS (EPA M ETHOD 1644) ................................ ................................ .......... 10 - 1 10.1 Summary

of Me thod ................................ ................................ .......................... 10 - 1 10.2 Test Requirements and Materials ................................ ................................ ....... 10 - 1 10.3 Procedures ................................ ................................ ................................ .......... 10 - 6 10.4 Recommended Test Conditions ................................ ................................ ......... 10 - 8 10.5 Biological Data ................................ ................................ ................................ 10 - 10 10.6 Quality

Control ................................ ................................ ................................ 10 - 10 10.7 Reference Tests ................................ ................................ ................................ 10 - 11 10.8 Interpretation of Result ................................ ................................ .................... 10 - 12 10.9 References ................................ ................................ ................................ ........ 10 - 13v **LIST OF TABLES Page**  Table 1 - 1. Methods by

Waste and Pollutant, Subpart A − Offshore Subcategory ...................... 1 - 2 Table 1 - 2. Methods by

Waste and Pollutant, Subpart D − Coastal Subcategory ........................ 1 - 4 Table 1 - 3. EPA Method Numbers for Oil and Gas Extraction Point Source Category

Analy tical Methods and Prior CFR References in 40 CFR 435 ............................. 1 - 10 Table 3 - 1. Example of a Randomization Schedule ................................ ................................ ...... 3 - 9 Table 3 - 2. Listing of Acute Toxicity Tes t Data (August 1983 to September 1983) With Eight Generic Drilling Fluids and My sid Shrimp ................................ ................... 3 - 11 Table 3 - 3. Partial Toxicity Test Passing Criteria ................................ ................................ ....... 3 - 12 Table 5 - 1. Test Acceptability Criteria ................................ ................................ ......................... 5 - 9 Table 6 - 1. Gas Chromatograph/Mass Spectrometer (GC/MS) Operation Conditions ................ 6 - 9 Table 6 - 2. Approximate Retention Time for Compounds ................................ ......................... 6 - 10 Table 6 - 3. Recommended I on Mass Numbers ................................ ................................ ........... 6 - 13 Table 9 - 1. Performance Data and Method Acceptance Criteria for PAH ................................ . 9 - 14 Table 9 - 2. HPLC Calibration Data ................................ ................................ ............................ 9 - 14 Table 10 - 1. Culture conditions for L . plumulosus. Conditions listed are consistent with

culture conditions specified in ASTM E 1367 - 92 and subsequent updates (E 1367 - 99) ................................ ................................ ................................ .................. 10 - 3 Table 10 - 2. Dry

food portion of the diet that has been used to successfull y culture L. plumulosus ................................ ................................ ................................ .............. 10 - 4 Table 10 - 3. Conditions for conducting 96 - hour NAF and 10 - day SBM sediment toxicity tests with L. plumulosus . Conditions listed are consistent with test conditions specified in ASTM E 1367 - 92 and subsequent updates ( E 1367 - 99) unless otherwise noted ................................ ................................ ................................ ....... 10 - 9 Table 10 - 4. Test acceptability requirements for 10 - day

NAF and 96 - hr SBM tests with L. plumulosus . Requirements listed are consistent with those specified in ASTM E 1367 - 92 and subsequent updates (E 1367 - 99) ................................ ................... 10 - 11vi **LIST OF FIGURES Page**  Figure 3 - 1. M ys id Randomization Procedure ................................ ................................ .............. 3 - 8 Figure 6 - 1. Schematic Flowchart for Qualitative Identification ................................ ............... 6 - 18 Figure 9 - 1. L iquid Chromatography of the Three - Component Standard and of No. 2 Diesel Oil ................................ ................................ ................................ ................ 9 - 151 - 1

**1. S**  **UMMARY OF M**  **ETHODS** This document is a compilation of all but one of the anal ytical methods nece ssary for demonstrating compliance with the requirements of 40 CFR Part 435, effluent limitations guidelines and standards for the Oil and Gas Extraction Point Source Category . These methods are tests for regulated pollutant parameters. The waste sources a nd pollutant parameters regulated in 40 CFR Part 435 are listed in the following tables along with the required anal ytical or test method, and the subpart that cites the method. Table 1 - 1 presents the waste sources and pollutant p arameters regulated by Subpart A

– Offshore Subcategory . Table 1 - 2 presents the same information for Subpart D

– Coastal Subcategory . These methods were developed during two rulemakings: Offshore Subcategory ( March 4, 1993 ; 58 FR 12454 ) and the S ynthetic - based Drilling Fluids (SBF) Effluent Guidelines (January 22, 2001; 66 FR 6849). These anal yt ic methods were developed in consultation and collaboration with industry . For example, the anal yt ic methods for the Offshore Subcategory w ere developed with industry

in the 1980’s and included the Static Sheen Test and Drilling Fluids Toxicity Test ( see August 26, 1985; 50 FR 34596). EPA again worked very closel y with industry

and adopted their recommendations in promulgating additional anal ytical methods for the Sy nthetic - based Drilling Fluids Effluent Guidelines ( see January 22, 2001; 66 FR 6893 ). These additional anal yt ical methods included tests for PAH content (as phenanthrene), sediment toxicity, biodegradation rate, and percentage of b ase fluid on drill cuttings (API retort method). EPA listed the analy

tic methods and in some cases re - printed the anal ytic methods in the Code of Federal Regulations (CFR). As previously

noted there is one method that is not included in this document, whi ch relates to Cook Inlet , Alaska, operators that are regulated by the Coastal subcategory

(Subpart D). The Coastal subcategory

prohibits the discharge non - aqueous drill cuttings unless there are technical limitations . Appendix 1 of 40 CFR Part 435 Subpart D provides the method for permit writers to determine when operators qualify for an exemption from the discharge prohibition. For those operators that quality for the exemption from the discharge prohibition EPA requires that these operators meet the same stock limitations and discharge limitations for drill cuttings associated with non - aqueous drilling fluids for operators in Offshore waters ( see 40 CFR §435.13 and §435.15 ) in order to discharge drill cuttings associated with non - aqueous drilling fluids . This method remains in 40 CFR 435 and is not included in this document. The remainder of this section provides a summary of the anal ytical methods used for Part 435.1 - 2

**Table 1**  **- 1**  **. Methods by Waste and Polluta nt, Subpart A**  **− Offshore Subcategory Waste source**  **Regulated Pollutant Param**  **eter Analytical/Test Method**  **Cited in 40 CFR Part**  Produced Water Oil & grease 40 CFR Part 136 §435.12, §435.13, §435.14, §435.15 Water - based drilling fluids and associated drill cuttings SPP Toxicity Drilling Fluids Toxicity Test EPA Method 1619 §435.13, §435.15 Free oil Static Sheen Test

EPA Method 1617 §435.12, §435.13, §435.14, §435.15 Diesel oil † ASTM specification D975 - 91 §435.13, §435.15 Mercury 40 CFR Part 136 §435 .13, §435.15 Cadmium 40 CFR Part 136 §435.13, §435.15 Drill cuttings associated with non aqueous drilling fluids: Discharge limitations Diesel oil † ASTM specification D975 - 91 §435.13, §435.15

Free oil Static Sheen Test

EPA Method 1617 §435.12, §435.1 4 SPP Toxicity Drilling Fluids Toxicity Test

EPA Method 1619 §435.13, §435.15 Drilling fluid sediment toxicity (4 - Day

Test) Method for Conducting a Sediment Toxicity Test with Leptocheirus Plumulosus and Non Aqueous Drilling Fluids or Synthetic -Based Drilling Muds (EPA Method 1644) after using Procedure for Mixing Base Fluids with Sediments EPA Method 1646 §435.13, §435.15

Formation oil Reverse Phase Extraction (RPE) Method for

Detection of Oil Contamination in Non Aqueous Drilling Fluids (NAF) EPA M ethod 1670 Which can be confirmed by : Determination of Crude Oil Contamination in Non - Aqueous Drilling Fluids by Gas Chromatography/Mass Spectrometry (GC/MS) EPA Method 1655 §435.13, §435.15

Base fluid retained on cuttings 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 §435.13, §435.151 - 3

**Table 1**  **- 1**  **. Methods by Waste and Polluta nt, Subpart A**  **− Offshore Subcategory Waste source**  **Regulated Pollutant Param**  **eter Analytical/Test Method**  **Cited in 40 CFR Part**  Drill cuttings associated with non aqueous drilling fluids: Stock limitations (C 16 – C 18 internal olefin) Mercury 40 CFR Part 136 §435.13, §435.15

Cadmium 40 CFR Part 136 §435.13, §435.15 Polynuclear Aromatic Hydrocarbons (PAH) PAH Content of Oil by HPLC/UV

EPA Method 1654, Revision A §435.13, §435.15 Base fluid sediment toxicity (10 - Day Test) Method for Conducting a Sediment Toxicity

Test with Leptocheirus Plumulosus and Non Aqueous Drilling Fluids or Synthetic -Based Drilling Muds (EPA Method 1644) after using Procedure for Mixing Base Fluids with Sediments EPA Method 1646 §435.13, §435 .15

Biodegradation rate Protocol for the Determination of Degradation

of Non - Aqueous Base Fluids in a Marine Closed Bottle Biodegradation Test System: Modified ISO 11734:1995 EPA Method 1647 §435.13, §435.15

Well treatment, completion, and workover flui ds Oil and grease 40 CFR Part 136 §435.13, §435.15

Free oil Static Sheen Test

EPA Method 1617 §435.12, §435.14 Deck drainage Free oil Visual sheen §435.12, §435.13, §435.14, §435.15 Domestic waste Foam Observation §435.13, §435.15

Floating solids Obs ervation §435.14, §435.15 All other domestic wa ste See 33 CFR part 151 ‡ §435.14, §435.15 Sanitary M10 Total residual chlorine 40 CFR Part 136 §435.12, §435.14, §435.15 Sanitary M9IM Floating solids Observation §435.12, §435.14, §435.15 §435.12

– Off shore BPT §435.13

– Offshore BAT §435.14

– Offshore BCT §435.15

– Offshore NSPS † There is no discharge of diesel oil ( see §435.13 and §435.15) . Diesel oil refers to the grade of distillate fuel oil, as specified in ASTM D975 - 91. ‡ This standard refe rences a U.S. Coast Guard regulation: Vessels Carrying Oil, Noxious Liquid Substances, Garbage, Municipal or Commercial Waste, And Ballast Water (33 CFR part 151). **Note:** The Offshore Subcategory bans the discharge of the following waste sources and thus there are no related analytical or test methods: non - aqueous drilling fluids (NAF s) and produced sand ( see §435.12, §435.13, §435.14, §435.1 5).1 - 4

**Table 1**  **- 2**  **. Methods by Waste and Po llutant, Subpart D**  **− Coastal Subcategory Waste source**  **Regulated Pollutant Param**  **eter Analytical/Test Method**  **Cited in 40 CFR Part**  Produced Water Oil & grease 40 CFR Part 136 §435.42, §435.43, §435.44, §435.45 Water - based drilling fluids, drill cuttings, and dewatering effluent SPP Toxicity Drilling Fluids Toxicity Test EPA Method 1619 §435.43, §435.45 Free oil Static Sheen Test

EPA Method 1617 §435.42, §435.43, §435.44, §435.45 Diesel oil † ASTM specification D975 - 91 §435.43, §435.45 Mercury 40 CFR Part 136 §435.43, §435.45 Cadmium 40 CFR Part 136 §435.43, §435.45 Well treatment, workover, and completion fluids Oil and grease 40 CFR Part 136 §435.43, §435.45

Free oil Static Sheen Test

EPA Method 1617 §435.42, §435.44 Deck drainage Free oil Vis ual sheen §435.42,§435.43, §435.44, §435.45 Domestic waste Foam Observation §435.43, §435.45

Floating solids and garbage Observation §435.42, §435.44, §435.45 Sanitary M10 Total residual chlorine 40 CFR Part 136 §435.42, §435.44, §435.45 Sanitary M9I M Floating solids Observation §435.42, §435.44, §435.45 §435.42

– Coastal BPT §435.43

– Coastal BAT §435.44

– Coastal BCT §435.45

– Coastal NSPS † T here is no discharge of diesel oil ( see §435.4 3 and §435.4 5) . Diesel oil refers to the grade of distill ate fuel oil, as specified in ASTM D975 - 91. **Notes:** (1) The Coastal Subcategory bans the discharge of the following waste sources and thus there are no related analytical or test methods: non - aqueous drilling fluids (NAFs) and produced sand ( see §435.42, § 435.43 , §435.44 , §435.45 ). (2) The Coastal Subcategory bans the discharge of drill cuttings associated with non - aqueous drilling fluids unless there are technical limitations ( see §435.4 3 and §435.4 5). Appendix 1 of 40 CFR Part 435 Subpart D provides the method for permit writers to determine when operators qualify for an exemption from this discharge prohibition. For those operators that quality for the exemption from the discharge prohibition EPA requires that these operators meet the same stock limitati ons and discharge limitations for drill cuttings associated with non - aqueous drilling fluids for operators in Offshore waters ( see 40 CFR §435.13 and §435.15) and no discharge of free oil (determined by the Static Sheen Test, required by §435.42, §435.44 ) in order to discharge drill cuttings associated with non - aqueous drilling fluids.1 - 5

**1.1 Static Sheen Test**  **(EPA M ethod**  **1617**

**)** Scope and Application This method is to be used as a compliance test for the “no discharge of free oil” requirement for discharges of drilling fluids, drill cuttings, and well treatment, completion and workover fluids. “Free oil” refers to any oil contained in a waste stream that when discharged will cause a film or sheen upon or a discoloration of the surface of the receiving water. Summa ry of Method S amples ( 15 - mL ) of drilling fluids or well treatment, completion, and workover fluids, and 15 - g samples (wet weight basis) of drill cuttings or produced sand are introduced into ambient seawater in a container having an air- to - liquid interface area of 1 , 000 cm 2 (155.5 in2 ) . Samples are dispersed within the container and observations made no more than one hour later to ascertain if these materials cause sheen, iridescence, gloss, or increased reflectance on the surface of the test seawater. The occurrence of any of these visual observations will constitute a demonstration that the tested material contains “free oil,” and therefore results in a prohibition of its discharge into receiving waters. **1.2 Drilling Fluids Toxicity Test**  **(EPA M ethod**  **1619**

**)** Scop e and Application This method is to be used as a compliance test for the suspended particulate phase (SPP) toxicity requirement for discharges of w ater - based drilling fluids, associated drill cuttings, and dewatering effluent and for drill cuttings associated with non

–aqueous drilling fluids. The test may be conducted as a full bioassay to estimate the concentration that is lethal to 50% of the test organisms (L C 50 ) or as a partial test to determine compliance with 40 CFR Part 435 requirements. Summary ofMethod Samples of drilling fluids or drilling mud from active field s ys tems are diluted with natural or artificial seawater, mixed, and settled for 1 hour. The suspended particulate phase (SPP) is decanted. The decanted solution, defined to be 100% SPP, is further diluted with seawater to obtain test concentrations. Mysidopsis bahia (my sid shrimp) are exposed to the test concentrations for 96 hours, at which time the living organisms are counted. For the full bioassay , a range of concentrations is tested an d the L C 50 is calculated. For the partial test, a negative control, 3% concentration, and positive control are tested. If the number of organisms killed in the 3% test concentration meets a number specified in the method, the test material passes the parti al toxicity test. **1.3 Procedure for Mixing Base Fluids**  **w ith Sediments**  **(EPA M ethod**  **1646**

**)** This method is used to amend uncontaminated and nontoxic (control) sediments with the base fluids that are used to formulate sy nthetic - based drilling fluids and other non - aqueous drilling fluids. Initially , control sediments are press - sieved through a 2 , 000 micron mesh sieve to remove large debris. Then the control sediments are press - sieve d through a 500 micron sieve to remove indigenous organisms that may prey on the test species or otherwise confound test results. The control sediment is h omogenize d to limit the effects of settling that may have occurred during storage. The control s ediments are homogenized before density determinations and before the addition of base fluid. Because base fluids are strongl y h ydrophobic and do not readily mix with1 - 6

sediment, care must be taken to ensure base fluids are thoroughl y homogenized within the sediment. All concentrations are weight - to - weight (mg of base fluid to kg of dry control s ediment). **1.4 Protocol for the Dete** **rmination of Degradation of Non -**  **Aqueous Base Fluids in a Marine Closed Bottle Biodegradation Test System: Modified ISO**  **11734:1995 (EPA**  **M ethod**  **1647**

**)** Scope and Application EPA promulgated the use of the marine anaerobic biodegradation analy tic method because it most closely

modeled the ability

of a drilling fluid to biodegrade anaerobically in marine environments (January

22, 2001; 66 FR 6864). This method determines the anaerobic degradation potential of mineral oils, paraff in oils and non - aque ous fluids (NAF) in sediments. These substrates are base fluids for f ormulating offshore drilling fluids. The test evaluates base fluid biodegradation rates by monitoring headspace gas production due to microbial degradation of the test fluid in natural marine sediment. Subsequent to this promulgation, EPA incorporated additional quality assurance procedures for the marine anaerobic biodegradation anal ytic method in the NPDES permit for the Western Gulf of Mexico (“Final NPDES General P ermit for New and Existing Sources and New Dischargers in the Offshore Subcategory of the Oil and Gas Extraction Category for the Western Portion of the Outer Continental Shelf of the Gulf of Mexico,” GMG290000, Appendix B). The additional quality assuran ce instructions in the GMG290000 more clearl y describe the sample preparation and compliance determination steps. Specificall y, these additional quality assurance procedures clarify that users must only

use headspace gas to determine compliance with the P art 435 effluent guidelines. EPA noticed its intention to include these additional quality assurance procedures into Part 435 in the “Guidelines Establishing Test Procedures for the Anal ys is of Pollutants Under the Clean Water Act” proposed rulemaking (Sep tember 23, 2010; 75 FR 58023 ). After responding to public comments EPA included these additional quality assurance procedures into Part 435 with the final rule. Summary of Method A mixture of marine/estuarine sediment, test substrate (h ydrocarbon or controls) , and seawater is placed into clean 120 ml (150 ml actual volume) Wheaton serum bottles. The test is run using four replicate serum bottles containing 2 , 000 mg carbon/kg dry weight concentration of test substrate in sediment. T he anaerobic (redox) cond ition of the bottles is evaluated using resazurin dye solution (dye is blue when oxygen is present, reddish in low ox ygen conditions and colorless if ox ygenfree). H eadspace air is removed with a nitrogen sparge before incubation begins. Gas production and composition are measured approximately every two weeks. G as production is measured using a pressure gauge. Barometric pressure is measured at the time of testing to make necessary volume adjustments. The test period is 275 day s. The results of EPA Method 1647 for the test fluid are compared against the reference fluid to determine whether the test fluid is eligible for discharge with drill cuttings.1 - 7

**1.5 Determination of Crude Oil Contamination in Non**  **- Aqueous Drilling Fluids by Gas**  **Chromatography/Mass Spectrom etry (GC/MS)**  **(EPA M ethod**  **1655**

**)** Scope and Application This method determines crude (formation) oil contamination, or other petroleum oil c ontamination, in non - aqueous drilling fluids (NAFs) b y comparing the gas chromatograph y/mass spectrometry (GC/MS) finge rprint scan and extracted ion scans of the test sample to that of an uncontaminated sample. It can be used for monitoring oil contamination of NAFs or monitoring oil contamination of the base fluid used in the NAF formulations. Summary of Method Analy sis o f NAF for crude oil contamination is a step - wise process. The analy st first performs a qualitative assessment of the presence or absence of crude oil in the sample. If crude oil is detected during this qualitative assessment, the analy st must perform a quantitative analy sis of the crude oil concentration . A sample of NAF is centrifuged to obtain a solids free supernate. The test sample is prepared by removing an aliquot of the solids free supernate, spiking it with internal standard, and analyzing it using GC/MS techniques. The components are separated b y the gas chromatograph and detected b y the mass spectrometer. Qualitative identification of crude oil contamination is performed b y comparing the Total Ion Chromatograph (TIC) scans and Extracted Ion Profile (EIP) scans of test sample to that of uncontaminated base fluids, and examining the profiles for chromatographic signatures diagnostic of oil contamination. The presence or absence of crude oil contamination observed in the full scan profiles and selected extracted ion profiles determines further sample quantitation and reporting requirements. If crude oil is detected in the qualitative anal ys is, quantitative anal ys is must be performed by calibrating the GC/MS using a designated NAF spiked with known concentrations of a designated oil . **1.6 Reverse Phase Extraction (RPE) Method for Detection of Oil Contamination in Non**  **** **Aqueous Drilling Fluids (NAF) (EPA M**  **ethod 1670** 

**)** Scope and Application This method is used for determination of crude or formation oil, or other p etroleum oil contamination, in non - aqueous drilling fluids (NAFs) . It 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. It 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. The 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 % . Summary o

f 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.1 - 8

**1.7 Determination**  **of the Amount Of Non**  **- Aqueous Drilling Fluid (N**  **AF ) Base Fluid**  **f**

**rom Drill Cuttings**  **b**

**y a**  **Retort Chamber (Derived From API**  **Recommended Practice 13 B** **– 2)**  **(EPA M**

**ethod 1674** 

**)** Scope and Application 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 properl y operating “Retort” instrument. Summary of Me thod 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. **1.8 PAH Content of Oil by HPLC/**  **UV (EPA Method 1654, Revision A)** Scope a nd Application This method is designed to determine the pol ynuclear aromatic hydrocarbon (PAH) content of oil by high - performance liquid chromatography (HPL C) with an ultra - violet absorption (UV) detector. The PAH co ntent is measured and reported as phenanthrene. For oil in drilling muds, this method is designed to be used in conjunction with the extraction procedure in EPA Method 1662. Summary o

f Method An oil sample is diluted in acetonitrile and a 20 - μLaliquot is injected into the HPL C. The PAHs are partially

separated by

HPL C and detected with the UV detector. Id entification of PAH (qualitative anal ys is) is performed b y 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 anal ys is is performed b y calibrating the HPL C with phenanthrene using an external standard technique, and using the calibration factor to determine the concentration of PAH in the sample. **1.9 Sediment Toxicity Test for NAF and SBM**  **(EPA Method 1644**  **)** Scope a nd Application This test method describes the procedures for obtaining data regarding the effects of non aqueous drilling fluids (NAFs) or s ynthetic based drilling muds (SBMs) on the marine amphipod, Leptocheirus plumulosus . EPA regulates the sediment toxicity in NAFs and SBMs that are discharged from oil and gas extraction facil ities in coastal and offshore waters as an indicator for toxic pollutants ( see 40 CFR 435.13, 435.15, 435.43, and 435.45). EPA established the use of this test and related limits to encourage the use of less toxic drilling fluids and additives. The sediment toxicity of the NAF - cuttings at the point of discharge is measured by this modified sediment toxicity test using a natural sediment and Leptocheirus plumulosus as the test organism. EPA promulgated the use of this method with revisions to the Oil and Ga s Extraction effluent guidelines (January

22, 2001; 66 FR 6849). This initial method was consistent with ASTM Standard Guide E 1367 - 92 (ASTM 1997). Subsequent to this rulemaking EPA updated this1 - 9

method in the NPDES permit for the Western Gulf of Mexico (GM G290000, Appendix A) to be consistent with ASTM E 1367 - 99. Section 10 of this document re - prints the sediment toxicity test from the NPDES permit for the Western Gulf of Mexico (GMG290000, Appendix A). Summary o

f Method Samples of NAFs and SBMs are exposed to cultured Leptocheirus plumulosus test organisms. This method relies on standardized bioassay benthic toxicity

procedures from ASTM E 1367 and EPA/600/R - 94/0258 along with modified sediment mixing procedures that address the unique properties of SBM (EP A Method 1646). Of the several species ty picall y used for these tests, Leptocheirus plumulosus was selected because it demonstrated the range of sensitivity to the base fluids that were under evaluation and provided both repeatability and discriminatory po wer. L. plumulosus live in fine - grained sediments and warm waters similar to the conditions found in the anticipated receiving environment of the Gulf of Mexico. L. plumulosus is also easy to culture in the lab and therefore available year - round for testin g . The onl y SBM drill cuttings that can be discharge are cuttings coated with NAF s and SBM that are as toxic or less toxic, but not more toxic, than the reference NAF and SBM (C 16 - C 18 internal olefin or C 12 - C 14 or C 8 ester) as measured b y LC 50 . This method tests the whole SBM (96 - hour exposure test, discharge limitation) and the NAF (10 - day exposure test, stock limitations). This method is referenced in 40 CFR 435.13, 435.15, 435.43, and 435.45 . **1.10 Previous Publication of Oil and Gas Extraction Point Source C**  **ategory Analytic Methods**  EPA previously

published the anal yt ical methods for the Oil and Gas Extraction Point Source Category in the Code of Federal Regulations (CFR). These methods were published as attachments to Subpart A (Offshore Subcategory). Table 1 - 3 provides a listing of these methods as they appear in the CFR and their current EPA method number. Subsequent to these rulemakings EPA proposed several changes to Part 435, Oil and Gas Extraction Point Source Category on 23 September 2010 (75 FR 58023) . EPA solicited comment on moving , and in two cases revis ing , the methods from 40 CFR Part 435, Subpart A (Offshore Subcategory) to this E PA document , which was included in the rulemaking record for the proposed rule. 1 EPA proposed to organize the analyti cal methods for the Offshore Subcategory into this document in order to allow for easier access to the methods for this category . EPA also proposed to incorporate additional quality assurance procedures in the marine anaerobic biodegradation analy

tic metho d (Appendix 4 to Subpart A of Part 435) and to correct some erroneous references and omissions in the method for identification of crude oil contamination (Appendix 5 to Subpart A of Part 435 ) . EPA noticed its intent to include these revisions to these two methods in the previous version of this document . EPA received three sets of comments on the above - proposed actions. EPA reviewed and responded to these comments ( see EPA - HQ - OW - 2010 - 0192 - 0101, EPA - HQ - OW - 2010 - 0192 - 0155, EPA - HQ - OW - 2010 - 0192 - 0127, and the Response to Comments Document, Docket No. EPA - HQ - OW - 2010 - 0192 ). In the final r ule making (2011) EPA retained the full publication of the Oil and Gas Extraction anal yt ical methods (Appendix 1 through 7 to Subpart A) from 40

1 See “ Guidelines Establishing Test Procedures for the Analysis of Pollutants Under the Clean Water Act; Analysis and Sampling Procedures ,” RIN 2040 - AF09, Docket No. EPA - HQ - OW - 2010 - 0192 - 0034 . Available at: http://www.epa.gov/regulations.1 - 10

CFR 435, Subpart A, and incorporat ed these methods by reference to this document. 2 Li ke any other changes to an EPA approved method, any changes to the methods in th is document will require a rulemaking. **Table 1**  **- 3**  **. EPA Method Numbers for Oil**  **and Gas Extraction Point Source Category**

**Analytical Methods and Prior CFR References in 40 CFR 435 Analytical/Test Method**  **EPA Method Number**  **Date First**

**Prom ulgated**  **CFR References** Static Sheen Test 1617 1993 Subpart A, Appendix 1 Drilling Fluids Toxicity Test 1619 1993 Subpart A, Appendix 2 Procedure for Mixing Base Fluids With Sediments 1646 2001 Subpart A, Appendix 3 Protocol for the Determination of Degradation of Non - Aqueous Base Fluids in a Marine Closed Bottle Biodegradation Test System: Modifie d ISO 11734:1995 1647 2001 Subpart A, Appendix 4 Determination of Crude Oil Contamination in Non Aqueous Drilling Fluids by Gas Chromatography/Mass Spectrometry (GC/MS) 1655 2001 Subpart A, Appendix 5 Reverse Phase Extraction (RPE) Method for Detection o f Oil Contamination in Non - Aqueous Drilling Fluids (NAF) 1670 2001 Subpart A, Appendix 6 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) 1674 2001 Subpart A, Appendix 7 Method for Conducting a Sediment Toxicity Test with Leptocheirus Plumulosus and Non - Aqueous Drilling Fluids or Synthetic - Based Drilling Muds 1644 2001 N/A † **† Note:**  EPA Method 1644 (sediment toxicity test) was first promulgated for use in 2001 but was incorporated by reference. Subsequent to this rulemaking EPA updated this method in the NPDES permit for the Western Gulf of Mexico (GMG290000, Appendix A) to be consistent with ASTM E 1367 - 99 (ASTM 2000). Section 10 of this docume nt re - prints the sediment toxicity test from the NPDES permit for the Western Gulf of Mexico (GMG290000, Appendix A) .

2 Federal regulations at 1 CFR 51.7 (c)(1) prohibit the incorporation by reference of material published previously in the Federal Register. These regulations prevent EPA from deleting these methods from 40 CFR 435.2 - 11

**2. S**  **TATIC S**  **HEEN T**  **EST (EPA**  **M ETHOD**  **1617 )**  **2.1 Scope and Application**  This method is to be used as a compliance test for the “no discharge of free oil” requirement for discharges of drilling fluids, drill cuttings, produced sand, and well treatment, completion and workover fluids. “Free oil” refers to any oil contained in a waste stream that when discharged will cause a film or sheen upon or a discol oration of the surface of the receiving water. **2.2 Summary of Method**  15 - mLsamples of drilling fluids or well treatment, completion, and workover fluids, and 15 - g samples (wet weight basis) of drill cuttings or produced sand are introduced into ambient seawate r in a container having an air- to - liquid interface area of 1 , 000 cm 2 (155.5 in2 ) . Samples are dispersed within the container and observations made no more than one hour later to ascertain if these materials cause a sheen, iridescence, gloss, or increased r eflectance on the surface of the test seawater. The occurrence of any of these visual observations will constitute a demonstration that the tested material contains “free oil,” and therefore results in a prohibition of its discharge into receiving waters. **2.3 Interferences**  Residual “free oil” adhering to sampling containers, the magnetic stirring bar used to mix the sample, and the stainless steel spatula used to mix the sample will be the principal sources of contamination problems. These problems should only occur if improperly washed and cleaned equipment are used for the test. The use of disposable equipment minimizes the potential for similar contamination from pipettes and the test container. **2.4 Apparatus, Materials, and Reagents**  2.4.1 Apparatus

2.4.1.1 Sampling Containers : 1 - liter polyeth yl ene beakers and 1 - liter glass

beakers. 2.4.1.2 Graduated cylinder: 100 - mLgraduated cylinder required only for operations where predilution of mud discharges is required. 2.4.1.3 Plastic disposable weighing boats. 2.4.1.4 Triple - beam scale. 2.4.1.5 Disposable pipettes: 25 - mLdisposable pipettes. 2.4.1.6 Magnetic stirrer and stirring bar. 2.4.1.7 Stainless steel spatula.2 - 12 2.4.1.8 Test container: Open plastic container whose internal cross - section

parallel to its opening has an area of 1 , 000 cm 2 ±50 cm2 (155.5 ±7.75 in2 ), and a depth of at least 13 cm (5 inches) and no more than 30 cm (11.8 inches). 2.4.2 Materials and Reagents.

2.4.2.1 Plastic liners for the test container: Oil - free, heavy- duty plastic trash can

liners that do not inhibit the spreading of an oil film. Liners must be of sufficient size to comp letely cover the interior surface of the test container. Permittees must determine an appropriate local source of liners that do not inhibit the spreading of 0.05 mLof diesel fuel added to the lined test container under the test conditions and protocol de scribed below. 2.4.2.2 Ambient receiving water. **2.5 Calibration**  None currentl y specified. **2.6 Quality Control Procedures**  None currentl y specified. **2.7 Sample Collection and Handling**  2.7.1 Sampling containers must be thoroughl y washed with detergent, rinsed a minimum of

three times with fresh water, and allowed to air dry before samples are collected. 2.7.2 Samples of drilling fluid to be tested shall be taken at the shale shaker after cuttings

have been removed. The sample volume should range between 200 mL and 500 mL . 2.7.3 Samples of drill cuttings will be taken from the shale shaker screens with a clean

spatula or similar instrument and placed in a glass beaker. Cuttings samples shall be collected prior to the addition of any washdown wat er and should range between 200 g and 500 g. 2.7.4 Samples of produced sand must be obtained from the solids control equipment from

which the discharge occurs on any given day

and shall be collected prior to the addition of any

washdown water; samples should range between 200 g and 500 g. 2.7.5 Samples of well treatment, completion, and workover fluids must be obtained from

the holding facility

prior to discharge; the sample volume should range between 200 mLand 500 mL. 2.7.6 Samples must be tested no later than 1 hour after collection. 2.7.7 Drilling fluid samples must be mixed in their sampling containers for 5 minutes prior

to the test using a magnetic bar stirrer. If predilution is imposed as a permit condition,2 - 13 the sample must be mixed at the same ratio with the same prediluting water as the discharged muds and stirred for 5 minutes. 2.7.8 Drill cuttings must be stirred and well mixed by hand in their sampling containers prior to testing, using a stainless steel spatula. **2.8 Procedure**  2.8.1 Ambient receiving water must be used as the “receiving water” in the test. The

temperature of the test water shall be as close as practicable to the ambient conditions in the receiving water, not the room temperature of the observation facility . The test container must have an air - to - liquid interface area of 1 , 000 ±50 cm 2. The surface of the water should be no more than 1.27 cm ( 0 .5 inch) below the top of the test container. 2.8.2 Plastic liners shall be used, one per test container, and discarded afterwards. Some

liners may

inhibit spreading of added oil; operators shall determine an appropriate local source of liners that do not inhibit the spreading of the oil film. 2.8.3 A 15 - mLsample of drilling fluid or well treatment, completion, and workover fluids

must be introduced b y pipette into the test container 1 cm below the water surface. Pipettes must be filled and discharged with test material prior to the transfer of test material and its introduction into test containers. The test water/test material mixture must be stirred using the pipette to distribute the test material homogeneously throughout the test water. The pipette must be used only once for a test and then discarded. 2.8.4 Drill cuttings or produced sand should be weighed on plastic weighing boats; 15 - g

samples must be transferred b y scraping test material into the test water with a stainless steel spatula. Drill cuttings shall not be prediluted prior to testing. Also, drilling fluids and cuttings will be tested separately. The weighing boat must be immersed in the test water and scraped with the spatula to transfer any residual material to the test container. The drill cuttings or produced sand must be stirred with the spatula to an even distribution of solids on the bottom of the test container. 2.8.5 Observations must be made no later than 1 hour after the test material is transferred to

the test container. Viewing point s above the test container should be made from at least three sides of the test container, at viewing angles of approximately 60° and 30° from the horizontal. I llumination of the test container must be representative of adequate lighting for a working environment to conduct routine laboratory procedures. It is recommended that the water surface of the test container be observed under a fluorescent light source such as a dissecting microscope light. The light source shall be positioned above and directed ove r the entire surface of the pan. 2.8.6 Detection of a “silvery” or “metallic” sheen or gloss, increased reflectivity, visual

color, iridescence, or an oil slick on the water surface of the test container surface shall constitute a demonstration of “free oil.” Th ese visual observations include patches, streaks, or sheets of such altered surface characteristics. If the free oil content of the sample approaches or exceeds 10%, the water surface of the test container may2 - 14 lack color, a sheen, or iridescence, due to th e increased thickness of the film; thus, the observation for an oil slick is required. The surface of the test container shall not be disturbed in any

manner that reduces the size of any sheen or slick that may

be present. If an oil sheen or slick occurs o n less than one - half of the surface area after the sample is introduced to the test container, observations will continue for up to 1 hour. If the sheen or slick increases in size and covers greater than one - half of the surface area of the test container d uring the observation period, the discharge of the material shall cease. If the sheen or slick does not increase in size to cover greater than one half of the test container surface area after one hour of observation, discharge may continue and additional sampling is not required. If a sheen or slick occurs on greater than one - half of the surface area of the test container after the test material is introduced, discharge of the tested material shall cease. The permittee may retest the material causing the s heen or slick. If subsequent tests do not result in a sheen or slick covering greater than one - half of the surface area of the test container, discharge may continue.3 - 1

**3. D**  **RILLING F**  **LUIDS T**  **OXICITY T**  **EST (EPA**  **M ETHOD**  **1619 )**  **3.1 Scope and Application**  This method is to be used as a compliance test for the suspended particulate phase (SPP) toxicity requirement for discharges of water - based drilling fluids, associated drill cuttings, and dewatering effluent and for drill cuttings associated with non

–aqueous drilling flui ds. The test may be conducted as a full bioassay to estimate the concentration that is lethal to 50% of the test organisms (L C 50 ) or as a partial test to determine compliance with 40 CFR Part 435 requirements. **3.2 Summary of Method**  Samples of drilling fluids or drilling mud from active field s ys tems are diluted with natural or artificial seawater, mixed, and settled for 1 hour. The suspended particulate phase (SPP) is decanted. The decanted solution, defined to be 100% SPP, is further diluted with seawater to obtain test concentrations. Mysidopsis bahia (my sid shrimp) are exposed to the test concentrations for 96 hours, at which time the living organisms are counted. For the full bioassay , a range of concentrations is tested and the L C 50 is calculated. For the partial test, a negative control, 3% concentration, and positive control are tested. If the number of organisms killed in the 3% test concentration meets a number specified in the method, the test material passes the partial toxicity test. **3.3 Sample Collecti** **on** The collection and preservation methods for drilling fluids (muds) and water samples presented here are designed to minimize sample contamination and alteration of the phy sical or chemical properties of the samples due to freezing, air oxidation, or drying. 3.3.1 Apparatus

3.3.1.1 The following items are required for water and drilling mud sampling and

storage: a. Acid - rinsed linear - pol yethylene bottles or other appropriate noncontaminating drilling mud sampler. b. Acid - rinsed linear - pol yethylene bottles or other appropriat e noncontaminating water sampler. c. Acid - rinsed linear - pol yethylene bottles or other appropriate noncontaminated vessels for water and mud samples. d. Ice chests for preservation and shipping of mud and water samples. 3.3.2 Water Sampling

3.3.2.1 Collection of water samples shall be made with appropriate acid - rinsed

linear - pol yeth yl ene bottles or other appropriate non - contaminating water sampling devices. Special care shall be taken to avoid the introduction of3 - 2 contaminants from the sampling devices and containers. Prior to u se, the sampling devices and containers should be thoroughl y cleaned with a detergent solution, rinsed with tap water, soaked in 10 % hydrochloric acid (HCl) for 4 hours, and then thoroughly rinsed with glass - distilled water. 3.3.3 Drilling Mud Sampling

3.3.3.1 Drilling mud formulations to be tested shall be collected from active field

sy stems. Obtain a well - mixed sample from beneath the shale shaker after the mud has passed through the screens. Samples shall be stored in polyeth yl ene containers or in other appropriate un contaminated vessels. Prior to sealing the sample containers on the platform, flush as much air out of the container b y filling it with drilling fluid sample, leaving a one inch space at the top. 3.3.3.2 Mud samples shall be immediately shipped to the testing faci lity on blue or wet ice (do not use dry ice) and continuously maintained at 0

–4 °C until the time of testing. 3.3.3.3 Bulk mud samples shall be thoroughly mixed in the laboratory

using a 1 , 000 rpm high shear mixer and then subdivided into individual, small wide - mouthed (e.g., one or two liter) non - contaminating containers for storage. 3.3.3.4 The drilling muds stored in the laboratory shall have any

excess air removed b y flushing the storage containers with nitrogen under pressure any time the containers are opened. Moreover , the sample in any container opened for testing must be thoroughly stirred using a 1 , 000 rpm high shear mixer prior to use. 3.3.3.5 Most drilling mud samples may be stored for periods of time longer than 2 weeks prior to toxicity

testing provided that proper cont ainers are used and proper condition are maintained. **3.4 Suspended Particulate Phase Sample Preparation**  Mud samples that have been stored under specified conditions in this protocol shall be prepared for tests within three months after collection. The SPP shal l be prepared as detailed below. 3.4.1 Apparatus

3.4.1.1 The following items are required:

a. Magnetic stir plates and bars. b. Several graduated cylinders, ranging in volume from 10 mLto 1 L c. Large (15 cm) powder funnels. d. Several 2 - liter graduated cylinders.3 - 3 e. Several 2 - liter large mouth graduated Erlenmeyer flasks. 3.4.1.2 Prior to use, all glassware shall be thoroughl y cleaned. Wash all glassware

with detergent, rinse five times with tap water, rinse once with acetone, rinse several times with distilled or deionized water, place in a clean 10 % (or stronger) HCl acid bath for a minimum of 4 hours, rinse five times with tap water, and then rinse five times with distilled or deionized water. For test samples containing mineral oil or diesel oil, glassware should be washed with petroleum ether to assure removal of all residual oil. Note: If the glassware with ny tex cups soaks in the acid solution longer than 24 hours, then an equally long deionized water soak should be performed. 3.4.2 Test Seawater Sample Preparation

3.4.2.1 Diluent seawater and exposure seawater samples are prepared b y filtration

through a 1.0 micrometer filter prior to anal ys is. 3.4.2.2 Artificial seawater may be used as long as the seawater has been prepared by standard methods or ASTM methods, has been properl y “seasoned,” filtered, and has been diluted with distilled water to the same speci fied 20 ±2 ppt salinity

and 20 ±2 °C temperature as the “natural” seawater. 3.4.3 Sample Preparation

3.4.3.1 The pH of the mud shall be tested prior to its use. If the pH is less than 9,

if black spots have appeared on the walls of the sample container, or if the mud sample has a foul odor, that sample shall be discarded. Subsample a manageable aliquot of mud from the well - mixed original sample. Mix the mud and filtered test seawater in a volumetric mud - to - water ratio of 1 to 9. This is best done by

the method of volumetric displacement in a 2

–L, large mouth, graduated Erlenmeyer flask. Place 1 , 000 mL of seawater into the graduated Erlenmeyer flask. The mud subsample is then carefully added via a powder funnel to obtain a total volume of 1200 mL . (A 200 mL volume of the mud will now be in the flask). The 2

–L, large mouth, graduated Erlenmeyer flask is then filled to the 2 , 000 mLmark with 800 mLof seawater, which produces a slurry with a final ratio of one volume drilling mud to nine volumes water. If the volume of SPP required for testing or anal ys is exceeds 1 , 500 to 1 , 600 mL , the initial volumes should be proportionatel y increased. Alternativel y, several 2

–L drill mud/water slurries may be prepared as outlined above and combined to provide sufficient SPP. 3.4.3.2 Mix this mud/water slurry with magnetic stirrers for 5 minutes. Measure

the pH and, if necessary , adjust (decrease) the pH of the slurry to within 0.2 units of the seawater by adding 6N HCl while stirring the slurry . Then, allow the slurry

to settle for 1 hour. Record the amount of HCl added.3 - 4 3.4.3.3 At the end of the settling period, carefull y decant (do not siphon) the

Suspended Particulate Phase (SPP) into an appropriate container. Decanting the SPP is one continuous action. In some cases no clear interface will be present; that is, there will be no solid phase that has settled to the bottom. For those samples the entire SPP solution should be used when preparing test concentrations. However, in those cases when no clear interf

ace is present, the sample must be remixed for five minutes. This insures the homogeneity of the mixture prior to the preparation of the test concentrations. In other cases, there will be samples with two or more phases, including a solid phase. For those samples, carefully and continuously

decant the supernatant until the solid phase on the bottom of the flask is reached. The decanted solution is defined to be 100 % SPP. Any other concentration of SPP refers to a percentage of SPP that is obtained by

volume trically

mixing 100 % SPP with seawater. 3.4.3.4 SPP samples to be used in toxicity tests shall be mixed for 5 minutes and must not be preserved or stored. 3.4.3.5 Measure the filterable and unfilterable residue of each SPP prepared for

testing. Measure the dissolved oxygen (DO) and pH of the SPP. I f the DO is less than 4.9 ppm, aerate the SPP to at least 4.9 ppm which is 65% of saturation. Maximum allowable aeration time is 5 minutes using a generic commercial air pump and air stone. Neutralize the pH of the SPP to a pH 7. 8 ± 0 .1 using a dilute HCl solution. I f too much acid is added to lower the pH saturated NaOH may

be used to raise the pH to 7.8 ± 0 .1 units. Record the amount of acid or NaOH needed to lower/raise to the appropriate pH. Three repeated DO and pH measurements are needed to insure homogeneity

and stability

of the SPP. Preparation of test concentrations may begin after this step is complete. 3.4.3.6 Add the appropriate volume of 100 % SPP to the appropriate volume of

seawater to obtain the desired SPP concentration. The control is seawater only . Mix all concentrations and the control for 5 minutes by using magnetic stirrers. Then, the animals shall be randomly selected and placed in the dishes in order to begin the 96 - hour toxicity test. **3.5 Guidance for Performing Suspended**  **Particulate Phase Toxicity Tests Using Mysidopsis bahia**  3.5.1 Apparatus

3.5.1.1 Each definitive test consists of 18 test containers: 3 replicates of a control

and 5 SPP dilutions. Test containers should be P yr ex or equivalent glass. For definitive tests, 5 SPP dilutions with 3 replicates of at least 500 ml each are required. Twenty my sids per replicate, 360 per definitive test are required. 3.5.1.2 A range - finding test consists of at least 6 test containers: 1 replicate of a

control and 5 SPP dilutions. The duration of range - fin ding tests may be3 - 5 less than 96 hours. Ten or more m ys ids per replicate, at least 60 per range finding test, are suggested. Daily water quality

measurements and observations are optional with range - finding tests. 3.5.2 Sample Collection Preservation

3.5.2.1 Drilling muds and water samples are collected and stored as described in

Section 3.3.3 . 3.5.3 Species Selection

3.5.3.1 The Suspended Particulate Phase (SPP) tests on drilling muds shall utilize

the test species Mysidopsis bahia . Test ani mals shall be 3 to 6 days old on the first day

of exposure. Whatever the source of the animals, collection and handling should be as gentle as possible. Transportation to the laboratory

should be in well - aerated water from the animal culture site at the te mperature and salinity from which they

were cultured. Methods for handling, acclimating, and sizing bioassay organisms given by

Borthwick [1] and Nimmo [2] shall be followed in matters for which no guidance is given here. 3.5.4 Experimental Conditions

3.5.4.1 Suspended particulate phase (SPP) tests should be conducted at a salinity

of 20 ±2 ppt. Experimental t emperature should be 20 ±2 °C. Dissolved oxygen in the SPP shall be raised to or maintained above 65 % of saturation prior to preparation of the test concentrations. Under these conditions of temperature and salinity , 65 % saturation is a DO of 5.3 ppm. Beginning at Day

0 - before the animals are placed in the test containers DO, temperature, salinity, and pH shall be measured every 24 hours. DO should be reported in mill igrams per liter. 3.5.4.2 Aeration of test media is required during the entire test with a rate

estimated to be 50

– 140 cubic centimeters/minute. This air flow to each test dish may

be achieved through pol yeth yl ene tubing (0.045 - inch inner diameter and 0.062 - inch o uter diameter) b y a small generic aquarium pump. The delivery

method, surface area of the aeration stone, and flow characteristics shall be documented. All treatments, including control, shall be the same. 3.5.4.3 Li ght intensity shall be 1 , 200 microwatts/cm2 using cool white fluorescent bulbs with a 14 - hr light and 10 - hr dark cycle. This light/dark cycle shall also be maintained during the acclimation period and the test. 3.5.5 Experimental Procedure

3.5.5.1 Wash all glassware with detergent, rinse five times with tap water, rinse

once with acetone, rinse several times with distilled or deionized water,3 - 6 place in a clean 10 % HCl acid bath for a minimum of 4 hours, rinse five times with tap water, and then rinse five times with distilled water. 3.5.5.2 Establish the definitive test concentration based on results of a range

finding test or based on prior experience and knowledge of the mud sy stem . A minimum of five test concentrations plus a negative and positive (reference toxicant) control is required for the definitive test. To estimate the L C 50 , two concentrations shall be chosen that give (other than zero and 100 % ) mortality above and below 50 % . 3.5.5.3 Twenty

organisms are exposed in each test dish. Ny tex® cups shall be inserted into every

test dish prior to adding the animals. These “nylon me sh screen” nyt ex holding cups are fabricated by gluing a collar of 363 - micrometer mesh nyl on screen to a 15 - centimeter wide Petri dish with silicone sealant. The nyl on screen collar is approximately 5 centimeters high. The animals are then placed into the test concentration within the confines of the Ny

tex cups. 3.5.5.4 Individual organisms shall be randomly assigned to treatment. A randomization procedure is presented in Section 3.7 . Make every attempt to expose animals of approximately equal size. The technique described by Borthwick [1], or other suitable substitutes, should be used for transferring specimens. Throughout the test period, my sids shall be fed daily with approximately 50 Artemia (brine shrimp) nauplii per mysid. This will reduce stress and decrease cannibalism. 3.5.5.5 Cover the dishes, aerate, and incubate the test containers in an appropriate

test chamber. Positioning of the test containers holding various concentrations of test solution should be randomized if incubator arrangement indicates potential position difference. The test medium is not replaced during the 96 - hour test. 3.5.5.6 Observations may be attempted at 4, 6 and 8 hours; they must be attempted at 0, 24, 48, and 72 hours and must be made at 96 hours. Attempts at observations refers to placing a test dish on a light table and visually counting the animals. Do not lift the “nylon mesh screen” cup out of the test dish to make the observation. No unnecessary handling of the animals should occur during the 96 ho ur test period. DO and pH measurements must also be made at 0, 24, 48, 72, and 96 hours. Take and replace the test medium necessary for the DO and pH measurements outside of the ny

tex cups to minimize stresses on the animals. 3.5.5.7 At the end of 96 hours, all li ve animals must be counted. Death is the end

point, so the number of living organisms is recorded. Death is determined by lack of spontaneous movement. All crustaceans molt at regular intervals, shedding a complete exoskeleton. Care should be taken not to count an exoskeleton. Dead animals might decompose or be eaten between observations. Therefore, alway s count living, not dead animals. If daily observations are made, remove dead organisms and molted exoskeletons3 - 7 with a pipette or forceps. Care must be taken not to disturb living organisms and to minimize the amount of liquid withdrawn. **3.6 Methods for Positive Control Tests (Reference Toxicant)** 

3.6.1.1 Sodium lauryl sulfate (dodecyl sodium sulfate) is used as a reference

toxicant for the positive control. The chemical used should be approximately

95 % pure. The source, lot number, and percent purity shall be reported. 3.6.1.2 Test methods are those used for the drilling fluid tests, except that the test

material was prepared b y weighing one gram sodium lauryl sulfate on an anal yt ical balance, adding the chemical to a 100 - milliliter volumetric flask, and bringing the flask to volume with deionized water. After mixing this stock solution, the test mixtures are prepared by adding 0.1 milliliter of the stock solution for each part p er million desired to one liter of seawater. 3.6.1.3 The mixtures are stirred briefl y, water quality is measured, animals are

added to holding cups, and the test begins. Incubation and monitoring procedures are the same as those for the drilling fluids. **3.7 Randomizat** 

**ion Procedure** 3.7.1 Purpose and Procedure

3.7.1.1 The purpose of this procedure is to assure that mys ids are impartiall y

selected and randoml y assigned to six test treatments (five drilling fluid or reference toxicant concentrations and a control) and impartially counte d at the end of the 96 - hour test. Thus, each test setup, as specified in the randomization procedure, consists of 3 replicates of 20 animals for each of the six treatments, i.e. , 360 animals per test. Figure 3 - 1 is a flow diagram that depicts the procedure schematically and should be reviewed to understand the over - all operation. The following tasks shall be performed in the order listed. 3.7.1.2 My sids are cultured in the laboratory in appropriate units. I f my sids are purchased, go to Tas k 3 (Section 3.7.1.3 ) . 3.7.1.3 Remove my sids from culture tanks (6, 5, 4, and 3 day s b efore the test will

begin, i.e. , Tuesday , Wednesday , Thursday , and Friday if the test will begin on Monday) and place them in suitabl y large maintenance containers so that they

can swim about freel y and be fed. Note: Not every

detail (the definition of suitably large containers, for example) is provided here. Training and experience in aquatic animal culture and testing will be required to successfully complete these tests.3 - 8

1 Culture Units

2 Maintenance Containers

3 Test Population Containers 4 Separation / Enumeration Containers 5 Counting Dish ( repeat tasks 5 - 7 for A 1 and A2 containers )

6 Distribution Containers

7 Test Containers A 1 A2 B 1 B 2

1 A 1 B 1 C 1 D 1 2 3 4 5 6 36

6 D If Mysids are purchased Mysids are collected 3 to 6 days prior to testing Task



# . . .

. . . **Figure 3**  **- 1**  **. Mysid Randomization Procedure** 3.7.1.4 Remove my sids from maintenance containers and place all animals in a

single container. The intent is to have homogeneous test population of my sids of a known age (3

– 6 day s old). 3.7.1.5 For each toxicity test, assign two suitable containers (500 - milliliter (mL) beakers are recommended) for m ys id separation/enumeration. Label each container (A1, A2, B1, B2, and C1, C2, for example, if two drilling fluid tests and a reference toxicant test are to be set up on one day). The purpose of this task is to allow the investigator to obtain a close estimate of the number of animals available for testing and to prevent unnecessary crowding of the m ys ids while the y are being counted and assigned to test containers. Transfer the my sids from the large test population container to the labeled separation and enumeration containers but do not place more than 200 my sids in a 500 - mLbeaker. Be impartial in transferring th e3 - 9 my sids; place approximately equal numbers of animals (10

– 15 my sids is convenient) in each container in a cyclic manner rather than placing the maximum number each container at one time. Note: It is important that the animals not be unduly stressed during this selection and assignment procedure. Therefore, it will probably be necessary to place all animals (except the batch immediately being assigned to test containers) in mesh cups with flowing seawater or in large volume containers with aeration. The ide a is to provide the animals with near optimal conditions to avoid additional stress. 3.7.1.6 Place the m ys ids from the two labeled enumeration containers assigned to

a specific test into one or more suitable containers to be used as counting dishes (2 - liter Caroli na dishes are suggested). Because of the time required to separate, count, and assign m ys ids, two or more people may be involved in completing this task. I f this is done, two or more counting dishes may

be used, but the investigator must make sure that app roximately

equal numbers of m ys ids from each labeled container are placed in each counting dish. 3.7.1.7 By

using a large - bore, smooth - tip glass pipette, select m ys ids from the counting dish(es) and place them in the 36 individually numbered distribution container s (10 - ml beakers are suggested). The m ys ids are assigned two at a time to the 36 containers b y using a randomization schedule similar to the one presented below. At the end of selection/assignment round 1, each container will contain two my sids; at the end of round 2, they

will contain four my sids; and so on until each contains ten my sids. **Table 3**  **- 1**  **. Example of a Randomization Schedule**  **Selection/assignment round (2 m** **ysids each) Place m** **ysid in the numbered dist ribution containers in the**  **random order shown**  1 8, 21, 6, 28, 33, 32, 1, 3, 10, 9, 4, 14, 23, 2, 34, 22, 36, 27, 5, 30,

35, 24, 12, 25, 11, 17, 19, 26, 31, 7, 20, 15, 18, 13, 16, 29. 2 35, 18, 5, 12, 32, 34, 22, 3, 9, 16, 26, 13, 20, 28, 6, 21, 24, 30, 8 ,

31, 7, 23, 2, 15, 25, 17, 1, 11, 27, 4, 19, 36, 10, 33, 14, 29. 3 7, 19, 14, 11, 34, 21, 25, 27, 17, 18, 6, 16, 29, 2, 32, 10, 4, 20, 3, 9,

1, 5, 28, 24, 31, 15, 22, 13, 33, 26, 36, 12, 8, 30, 35, 23. 4 30, 2, 18, 5, 8, 27, 10, 25, 4, 20, 26, 15, 31, 3 6, 35, 23, 11, 29, 16,

17, 28, 1, 33, 14, 9, 34, 7, 3, 12, 22, 21, 6, 19, 24, 32, 13. 5 34, 28, 16, 17, 10, 12, 1, 36, 20, 18, 15, 22, 2, 4, 19, 23, 27, 29, 25,

21, 30, 3, 9, 33, 32, 6, 14, 11, 35, 24, 26, 7, 31, 5, 13, 8. 3.7.1.8 Transfer my sids from the 36 di stribution containers to 18 labeled test

containers in random order. A label is assigned to each of the three replicates (A, B, C) of the six test concentrations. Count and record the 96 hour response in an impartial order.3 - 10 3.7.1.9 Repeat Tasks 5

–7 (Sections 3.7.1.5 through 3.7.1.7 ) for each toxicity test. A new random schedule should be followed in Tasks 6 and 7 for e ach test. Note: If a partial toxicity

test is conducted, th e procedures described above are appropriate and should be used to prepare the single test concentration and control, along with the reference toxicant test. 3.7.2 Data Anal ys is and Interpretation

3.7.2.1 Complete survival data in all test containers at each observation time shall

be presented in tabular form. If greater than 10 % mortality occurs in the controls, all data shall be discarded and the experiment repeated. Unacceptabl y high control mortality indicates the presence of important stresses on the organisms other than the material being tested, such as injury or disease, stressful phy sical or chemical conditions in the containers, or improper handling, acclimation, or feeding. If 10 % mortality or less occurs in the controls, the data may be evaluated and reported. 3.7.2.2 A definitive, full bioassay conducted according to the EPA protocol is used to estimate the concentration that is lethal to 50 % of the test organisms that do not die naturally . This toxicity measure is known as the median lethal concentration, or L C 50 . Th e LC 50 is adjusted for natural mortality or natural responsiveness. The maximum likelihood estimation procedure with the adjustments for natural responsiveness as given by D.J. Finney , in Probit Anal ys is 3rd edition, 1971, Cambridge University Press, chapt er 7, can be used to obtain the probit model estimate of the LC 50 and the 95 % fiducial (confidence) limits for the LC 50 . These estimates are obtained using the logarithmic transform of the concentration. The heterogeneity

factor (Finney

1971, pages 70

–72) is not used. For a test material to pass the toxicity test, according to the requirements stated in the offshore oil and gas extraction industry BAT effluent limitations and NSPS, the LC 50 , adjusted for natural responsiveness, must be greater than 3 % suspe nded particulate phase (SPP) concentration by volume unadjusted for the 1 to 9 dilution. Other toxicity test models may

be used to obtain toxicity

estimates provided the modeled mathematical expression for the lethality rate must increase continuously with concentration. The lethality rate is modeled to increase with concentration to reflect an assumed increase in toxicity with concentration even though the observed lethality may not increase uniformly

because of the unpredictable animal response fluctuatio ns. 3.7.2.3 The range finding test is used to establish a reasonable set of test

concentrations in order to run the definitive test. However, if the lethality rate changes rapidly

over a narrow range of concentrations, the range finding assay

may be too coarse to establish an adequate set of test concentrations for a definitive test.3 - 11 3.7.2.4 The EPA Environmental Research Laboratory in Gulf Breeze, Florida prepared a Research and Development Report entitled Acute Toxicity of Eight Drilling Fluids to My sid Shrimp ( Mysidopsis bahia ) , May

1984 EPA

– 600/3

– 84

–067. The Gulf Breeze data for drilling fluid number 1 are displayed in Table 3 - 2 for purposes of an example of the probit anal ys is described above. The SAS Probit Procedure (SAS Institute, Statistic al Analy sis S ys tem, Cary , North Carolina, 1982) was used to anal yz e these data. The 96 - hour L C 50 adjusted for the estimated spontaneous mortality rate is 3.3 % SPP with 95 % limits of 3.0 and 3.5 % SPP with the 1 to 9 dilution. The estimated spontaneous mortality rate based on all of the data is 9.6 % . **Table 3**  **- 2**  **. Listing of Acute Toxicity Test Data (August 1983 to September 1983)**  **W ith Eight**  **Generic Drilling Fluids and Mysid Shrimp**

[fluid N2=1] **Percent C oncentration**  **Number E**  **xposed Number**  **D ead (96 hours)**  **Number A**  **live (96 hours)**

0 60 3 57 1 60 11 49 2 60 11 49 3 60 25 35 4 60 48 12 5 60 60 0 3.7.3 The Partial Toxicity Test for Evaluation of Test Material 3.7.3.1 A partial test conducted according to EPA protocol can be used

economicall y to demonstrate that a test material passes the toxicity test. The partial test cannot be used to estimate the LC 50 adjusted for natural response. 3.7.3.2 To conduct a partial test follow the test protocol for preparation of the test

material and organ isms. Prepare the control (zero concentration), one test concentration (3 % suspended particulate phase) and the reference toxicant according to the methods of the full test. A range finding test is not used for the partial test. 3.7.3.3 Sixty

test organisms are us ed for each test concentration. Find the number of test organisms killed in the control (zero percent SPP) concentration in the column labeled X 0 of Table 3 - 3 . If the number of organisms in the control (zero percent SPP) exceeds the table values, then the test is unacceptable and must be repeated. If the number of organisms killed in the 3 % test concentration is less than or equal to corresponding number in the column labeled X 1 then the test material passes the partial toxicity te st. Otherwise the test material fails the toxicity test. 3.7.3.4 Data shall be reported as percent suspended particulate phase.3 - 12 **Table 3**  **- 3**  **. Partial Toxicity Test Passing Criteria Number Killed in Control (** **X 0**  **) Number**  **Killed in Test ( X**  **1 )** 

0 22 1 22 2 23 3 23 4 24 5 24 6 25 **3.8 References**  1. Borthwick, Patrick W. 1978. Methods for acute static tox icity tests with my sid shrimp ( Mysidopsis bahia ). Bioassay Procedures for the Ocean Disposal Permit Program, [EPA

– 600/9

–78

–0 10:] March. 2. Nimmo, D.R., T.L . Hamaker, and C.A. Some rs. 1978. Culturing the my sid ( Mysidopsis bahia ) in flowing seawater or a static s ys tem. Bioassay Procedures for the Ocean Disposal Permit Program, [EPA

– 600/9

–78

–010]: March. 3. American Public Health Associ ation et al. 1980. Standard Methods for the Examination of Water and Wastewater. Washington, DC, 15th Edition: 90

– 99. 4. U.S. Environmental Protection Agency , September 1991. Methods for Measuring the Acute Toxicity

of Effluents and Receiving Waters to Freshw ater and Marine Organisms. EPA/600/4

– 90/027. Washington, DC, 4th Edition. 5. Finney , D.J. Probit Analy sis. Cambridge University Press; 1971. 6. U.S. Environmental Protection Agency , May 1984. Acute Toxicity

of Eight Drilling Fluids to My sid Shrimp ( Mysidopsis ba hia ) . EPA

– 600/3

– 84

–067.4 - 1

**4. P**  **ROCEDURE FOR M**  **IX ING**  **B ASE**  **F LUIDS**  **W ITH**  **S EDIMENTS**  **(EPA M**  **ETHOD 1646**  **)** This procedure describes a method for amending uncontaminated and nontoxic (control) sediments with the base fluids that are used to formulate sy nthetic - based drill ing fluids and other non - aqueous drilling fluids. Initiall y, control sediments shall be press - sieved through a 2 , 000 micron mesh sieve to remove large debris. Then press - sieve the sediment through a 500 micron sieve to remove indigenous organisms that may prey on the test species or otherwise confound test results. Homogenize control sediment to limit the effects of settling that may have occurred during storage. Sediments should be homogenized before density determinations and addition of base fluid to control sediment. Because base fluids are strongl y h ydrophobic and do not readil y mix with sediment, care must be taken to ensure base fluids are thoroughly homogenized within the sediment. All concentrations are weight - to - weight (mg of base fluid to kg of dry control sediment). Sediment and base fluid mixing shall be accomplished by using the following method. **4.1 Determin**  **ing the**  **W et to**  **D ry**  **R atio for the**  **C**

**ontrol S**  **ediment** Determine the wet to dry ratio for the control sediment by weighing approximately 10 g subsamples of the screened and homogenized wet sediment into tared aluminum weigh pans. Dry sediment at 105 °C for 18

–24 h. Remove sediment and cool in a desiccator until a constant weight is achieved. Re - weigh the samples to determine the dry weight. Determine the wet/dry ratio by dividing the net wet weight by the net dry weight: [ 4 - 1 ] **4.2 Determining the Density of the Wet Control or Dilution Sediment**  Determine the density

(g/mL) of the wet control or dilution sediment. This shall be used to determine total volume of wet sediment needed for the various test treatments. [ 4 - 2 ] **4.3 Determining the Amount of Base Flu**  **id Needed** To determine the amount of base fluid needed to obtain a test concentration of 500 mg base fluid per kg dry

sediment use the following formulas: Determine the amount of wet sediment required: [ 4 - 3 ] Determine the amount of dry sediment in kilograms (kg) required for each concentration: Wet Sediment Density (g/mL) × Volume of Sediment Required

per Concentration (mL) = Weight Wet Sediment Required per Con c. (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)4 - 2 [ 4 - 4 ]

Finally , determine the amount of base fluid required to spike the control sediment at each concentration: [ 4 - 5 ] For spiking test substances other than pure base fluids (e.g., whole mud formulations), determine the spike amount as follows: [ 4 - 6 ] **4.4 P**  **rimary M**  **ixing** For primary

mixing, place appropriate amounts of weighed base fluid into stainless mixing bowls, tare the vessel weight, then add sediment and mix with a high - shear dispersing impeller for 9 minutes. The concentration of base fluid in sediment from this mix, rather than the nominal concentration, shall be used in calculating LC 5 0 values. **4.5 Testing for Homogeneity of Base Fluid**  Tests for homogeneity of base fluid in sediment are to be performed during the procedure development phase. Because of difficulty of homogeneousl y mixing base fluid with sediment, it is important to demonstrate that the base fluid is evenly mixed with sediment. The sediment s hall be anal yz ed for total petroleum hydrocarbons (TPH) using EPA Methods 3550A and 8015M, with samples taken both prior to and after distribution to replicate test containers. Base - fluid content is measured as TPH. After mixing the sediment, a minimum of three replicate sediment samples shall be taken prior to distribution into test containers. After the test sediment is distributed to test containers, an additional three sediment samples shall be taken from three test containers to ensure proper distribution of base fluid within test containers. Base - fluid content results shall be reported within 48 hours of mixing. The coefficient of variation (CV) for the replicate samples must be less than 20%. If base - fluid content results are not within the 20% CV lim it, the test sediment shall be remixed. Tests shall not begin until the CV is determined to be below the maximum limit of 20%. During the test, a minimum of three replicate containers shall be sampled to determine base - fluid content during each sampling pe riod. **4.6 Commencing the Sediment Toxicity Test**  Mix enough sediment in this way to allow for its use in the preparation of all test concentrations and as a negative control. When commencing the sediment toxicity test, range - finding tests may be required to det ermine the concentrations that produce a toxic effect if these data are otherwise unavailable. The definitive test shall bracket the LC 5 0 , which is the desired endpoint. The results for the base fluids shall be reported in mg of base fluid per kg of dry se diment. Conc. Desired (m g/kg) × Dry

Weight Sediment (kg) = Base Fluid Required (mg)

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 g4 - 3

**4.7 References**  1. American Society for Testing and Materials (ASTM). 1996. Standard Guide for Collection, Storage, Characterization, and Manipulation of Sediments for Toxicological Testing. ASTM E 1391

– 94. Annual Book of ASTM Standards, Volume 11.05, pp. 805

– 825. 2. Ditsworth, G.R., D.W. Schults and J.K.P. Jones. 1990. Preparation of benthic substrates for sediment toxicity

testing, Environ. Toxicol. Chem. 9:1523

– 1529. 3. Suedel, B.C., J.H. Rodgers, Jr. and P.A. Clifford. 1993. Bioavailability of fluoranthene in freshwater sediment toxicity tests. Environ. Toxicol. Chem. 12:155

– 165. 4. U.S. EPA. 1994. Methods for Assessing the Toxicity of Sediment - associated Contaminants with Estuarine and Marine Amphipods. EPA/600/R

– 94/025. Office of Research and Development, Washi ngton, DC. 5. U.S. EPA. 2001. Effluent L imitations Guidelines and New Source Performance Standards for the Oil and Gas E xtraction Point Source Category . Federal Register, 66: 6849 (22 January

2001). 6. U.S. EPA. 2001. Effluent L imitations Guidelines and New Source Performance Standards for the Oil and Gas Extraction Point Source Category : Correction . Federal Register, 66: 30811 ( 8 June 2001).5 - 1

**5. P**  **ROTOCOL FOR THE D**  **ETERMINATION OF D**  **EGRADATION OF N**  **ON -** **A QUEOUS**  **B ASE**  **F LUIDS IN A**  **M ARINE**  **C LOSED**  **B OTTLE**  **B IODEGRADATION**  **T EST**  **S YSTEM**  **: M**  **ODIFIED ISO**  **11734:1995 (EPA**  **M ETHOD**  **1647) 5.1**  **Summary of Method** This method determines the anaerobic degradation potential of mineral oils, paraffin oils and non - aqueous fluids (NAF) in sediments . These substrates are base fluids for formulating offsh ore drilling fluids . The test evaluates base fluid biodegradation rates by monitoring gas production due to microbial degradation of the test fluid in natural marine sediment. The test procedure places a mixture of marine/estuarine sediment, test substrat e (h ydrocarbon or controls) and seawater into clean 120 ml (150 ml actual volume) Wheaton serum bottles . The test is run using four replicate serum bottles containing 2 , 000 mg carbon/kg dry weight concentration of test substrate in sediment. The use of res azurin dye solution (1 ppm) evaluates the anaerobic (redox) condition of the bottles (dye is blue when oxygen is present, reddish in low oxygen conditions and colorless if ox ygen free) . After capping the bottles, a nitrogen sparge removes air in the headsp ace before incubation begins . During the incubation period, the sample should be kept at a constant temperature of 29 ± 1 ° C . Gas production and composition is measured approximately

every two weeks. The samples need to be brought to ambient temperature befo re making the measurements. Measure gas production using a pressure gauge. Barometric pressure is measured at the time of testing to make necessary volume adjustments . ISO 11734:1995 specifies that total gas is the standard measure of biodegradation . Whil e modifying this test for evaluating biodegradation of NAF s, methane was also monitored and found to be an acceptable method of evaluating biodegradation . Section 5.7 contains the procedures used to follow biodegradation by methane production . Measurement of either total gas or methane production is permitted . If methane is followed, determine the composition of the gas b y using gas chromatograph y (GC) anal ys is at each sampling . At the end of the test when gas production stops, or at around 275 day s, an analy sis of sediment for substrate content is possible . Common methods which have been successfully used for analyzing NAF s from sediments are listed in Section 5.8 . **5.2 System Requirements**  This environmental test sy stem has three phases, spiked sediment, overl yi ng seawater, and a gas headspace . The sediment/test compound mixture is combined with sy nthetic sea water and transferred into 120 mL serum bottles . The total volume of sediment/sea water mixture in the bottles is 75 mL . The volume of the sediment layer will be approximately 50 mL , but the exact volume of the sediment will depend on sediment characteristics (wet:dry ratio and density) . The amount of sy

nthetic sea water will be calculated to bring the total volume in the bottles to 75 mL . The test sy stems are maintained at a temperature of 29 ± 1 o C during incubation . The test sy stems are brought to ambient temperatures prior to measuring pressure or gas volume. 5.2.1 Sample Requirements

The concentration of base fluids are at least 2 , 000 mg carbon test material/kg dry sediment . Carbon concentration is determined by theoretical composition based on the chemical formula or by chemical analy sis by

ASTM D5291 - 96 . Sediments with5 - 2 positive, intermediate and negative control substances as well as a C 16 –C 18 internal olefin ty pe base fluid will be run in conjunction with test materials under the same conditions . The positive control is ethyl oleate (CAS 111 - 62 - 6), the intermediate control is 1 - hexadecene (CAS 629 - 73 - 2) , and the negative control is squalane (CAS 111 - 01 - 3) . Controls must be of anal ytical grade or the highest grade available . Each test control concentration should be prepared according to the mixing procedure described in Section 5.3.1 . Product names will be used for examples or clarification in the following text . Any use of trade or product names in this publication is for descriptive use only, and dos not constitute endorsement by EPA or the authors 5.2.2 Seawater R equirements

Sy nthetic seawater at a salinity of 25 ± 1 ppt should be used for the test . The sy nthetic seawater should be prepared b y mixing a commercially available artificial seawater mix, into high purity

distilled or de - ionized water . The seawater should be aerated and allowed to age for approximately one month prior to use. 5.2.3 Sediment Requirements

The dilution sediment must be from a natural estuarine or marine environment and be free of the compounds of interest . The collection location, date and time wil l be documented and reported . The sediment is prepared by press - sieving through a 2 , 000 - micron mesh sieve to remove large debris, then press - sieving through a 500 - micron sieve to remove indigenous organisms that may confound test results . The water content of the sediment should be less than 60% (w/w) or a wet to dry ratio of 2.5 . The sediment should have a minimum organic matter content of 3% (w/w) as determined b y ASTM D2974 - 87 (95) (Method A and D and calculate organic matter as in Section 12 of method A STM D2974 - 87). To reduce the osmotic shock to the microorganisms in the sediment the salinity of the sediment’s pore water should be between 20 - 30 ppt . Sediment should be used for testing as soon as possible after field collection . If required, sediment c an be stored in the dark at 4° C with 3 - 6 inches of overl yi ng water in a sealed container for a maximum period of 2 months prior to use. **5.3 Test Set**  **U**

**p** The test is set up by

first mixing the test or control substrates into the sediment inoculum, then mixing in seawater to make a pourable slurry . The slurry is then poured into serum bottles, which are then flushed with nitrogen and sealed. 5.3.1 Mixing Procedure

Because base fluids are strongl y h ydrophobic and do not readily mix with sediments, care must be taken to ensure base fluids are thoroughl y homogenized within the sediment . All concentrations are weight - to - weight comparisons (mg of base fluid to5 - 3 kg of dry control sediment) . Sediment and base fluid mixing will be accomplished by using the following method. 5.3.1.1 Det ermine the wet to dry weight ratio for the control sediment by

weighing approximately

10 sub - samples of approximately 1 g each of the screened and homogenized wet sediment into tared aluminum weigh pans . Dry sediment at 105 ° C for18 - 24 h . Remove the dried s ediments and cool in a desiccator . Repeat the drying, cooling, and weighing cycle until a constant weight is achieved (within 4% of previous weight) . Re - weigh the samples to determine the dry weight . Calculate the mean wet and dry weights of the 10 sub samples and determine the wet/dry ratio b y dividing the mean wet weight by

the mean dry

weight using Equation 5 - 1. This is required to determine the weight of wet sediment needed to prepare the test samples. [ 5 - 1 ] 5.3.1.2 Determine the density (g/ml) of the wet sediment . This will be used to determine total volume of wet sediment needed for the various test treatments . One method is to tare a 5 ml graduated cylinder and add about 5 ml of h omogenized sediment . Carefully record the volume then weigh this volume of sediment . Repeat this a total of three times . To determine the wet sediment density, divide the weight by volume per the following formula: [ 5 - 2 ] 5.3.1.3 Determine the amount of base fluid to be spiked into wet sediment in

order to obtain the desired initial base fluid concentration of 2 , 000 mg carbon/kg dry

weight . An amount of wet sediment that is the equivalent of 30 g of dry

sediment will be added to each bottle. A ty pical procedure is to prepare enough sediment for 8 serum bottles (3 bottles to be sacrificed at the start of the test, 4 bottles incubated for headspace anal ys is, and enough extra sediment for 2 extra bottles) . Extra sediment is needed because some of the sediment will remain coated onto the mixing bowl and utensils . Experience with this test may indicate that preparing larger volumes of spiked sediment is a useful practice, then the following calculations should be adjusted accordingl y. a. Determine the total weight of dry sediment needed to add 30 g dry sediment to 8 bottles . If more bottles are used then the calculations should be modified accordingl y . For example: 30 g dry sediment per bottle × 8 = 240 g dry sediment [ 5 - 3 ] Me an 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)5 - 4 b. Determine the weight of base fluid, in terms of carbon, needed to obtain a final base fluid concentration of 2 , 000 mg carbon/kg dry weight. For example: [ 5 - 4 ] c. Convert from mg of carbon to mg of base fluid. This calculation will depend on the % fraction of carbon present in the molecular structure of each base fluid . For the control fluids, eth ylole ate is composed of 77.3% carbon, hexadecene is composed of 85.7% carbon, and squalane is composed of 85.3% carbon . The carbon fraction of each base fluid should be supplied by the manufacturer or determined before use . ASTM D5291 - 96 or equivalent will used to determine composition of fluid. To calculate the amount of base fluid to add to the sediment, divide the amount of carbon (480 mg) b y the percent fraction of carbon in the fluid. For example, the amount of ethyl oleate added to 240 g dry weight sediment can be calculated from the following equation: [ 5 - 5 ] Therefore, add 621 mg of ethyl oleate to 240 g dry weight sediment for a final concentration of 2 , 000 mg carbon/kg sedim ent dry weight. 5.3.1.4 Mix the calculated amount of base fluid with the appropriate weight of wet

sediment. a. Use the wet:dry

ratio to convert from g sediment dry weight to g sediment wet weight, as follows: 240 g dry sediment × wet:dry ratio = g wet sediment neede d [ 5 - 6 ] b. Weigh the appropriate amount of base fluid (calculated in Section 5.3.1.3c ) into stainless mixing bowls, tare the vessel weight, then add the wet sediment calculated in E quation 5 - 5, and mix with a high shear dispersing impeller for 9 minutes. The sediment is now mixed with sy nthetic sea water to form a slurry that will be transferred into the bottles . 5.3.2 Creating Seawater/Sediment Slurry

Given that the total volume of sediment/sea water slurry in each bottle is to be 75 mL , determine the volume of sea water to add to the wet sediment.

480 mg carbon = 621 mg ethyl oleate (77 .3 ÷ 100) 2,000 mg carbon × 240 g = 480 mg carbon Per kg dry

sediment 1,0005 - 5 5.3.2.1 If each bottle is to contain 30 g dry sediment, calculate the weight, and then the volume, of wet sediment to be added to eac h bottle 30 g dry sediment × wet:dry

ratio = g wet sediment added to each bottle [ 5 - 7 ] [ 5 - 8 ] 5.3.2.2 Calculate volume of sea water to be added to each bottle 75 mLtotal volume

– mL wet sediment (from Eq. 8) = mL of sea water [ 5 - 9 ] 5.3.2.3 Determine the ratio of sea water to wet sediment (volume:volume) in each

bottle [ 5 - 10 ] 5.3.2.4 Convert the wet sediment weight from E quation 5 - 6 into a volume using

the sediment density . g wet sediment ( Eq. 5 - 6) density = volume (mL) of sediment [ 5 - 11 ] 5.3.2.5 Determine the amount of sea water to mix with the wet sediment. [ 5 - 12 ]

Mix sea water thoroughly with wet sediment to form a sediment/sea water slurry . 5.3.3 Bottling th e Sediment Seawater Slurry

The total volume of sediment/sea water slurry in each bottle is to be 75 mL . Convert the volume (mL) of sediment/sea water slurry into a weight (g) using the density of the sediment and the seawater. 5.3.3.1 Determine the weight of sedim ent to be added to each bottle mLsediment (Eq. 5 - 8) × density of wet sediment (g/mL) = g wet sediment [ 5 - 13 ] 5.3.3.2 Determine the weight of sea water to be added to each bottle mLsea water (Eq. 5 - 9) × density of sea water (1.01 g/mL) = g sea water [ 5 - 14 ] 5.3.3.3 Determine weight of sediment/sea water slurry to be added to each bottle g wet sediment (Eq. 5 - 13) + g sea water (Eq. 5 - 14) = g sediment/sea water slurry [ 5 - 15 ] This should provide each bottle with 30 g dry sediment in a total volume of 75 mL . mL wet sediment (Eq. 5 - 11) × Sea water:sediment ratio

(Eq. 5 - 10) = mL

sea water to add to wet sediment g wet sediment = mLwet 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)5 - 6 5.3.3.4 Putting the sediment:seawater slurry in the serum bottles. Note: The slurry

will need to be constantly stirred to keep th e sediment suspended. Place a tared serum bottle on a balance and add the appropriate amount of slurry to the bottle using a funnel. On ce the required slurry is in the bottle remove the funnel, add 2 - 3 drops (25 μL) of a 1 gram/Lresazurin dye stock solution. Cap the bottle with a butyl rubber stopper (Bellco Glass, Part #2048 - 11800) and crimp with an aluminum seal (Bellco Glass Part #20 48 - 11020). Using a plastic tube with a (23 gauge, 1 inch long) needle attached to one side and a nitrogen source to the other, puncture the serum cap with the needle. Puncture the serum cap again with a second needle to sparge the bottle’s headspace of res idual air for two minutes. The nitrogen should be flowing at no more than 100 mL/min to encourage gentle displacement of oxygenated air with nitrogen. Faster nitrogen flow rates would cause mixing and complete ox ygen removal would take much longer. Remove the nitrogen needle first to avoid any initial pressure problems. The second (vent) needle should be removed within 30 seconds of removing the nitrogen needle. Triplicate blank test s ys tems are prepared, with similar quantities of sediment and seawater without any base fluid. Incubate in the dark at a constant temperature of 29  1°C. Record the test temperature. The test duration is dependent on base fluid performance, but at a maximum should be no more than 275 day s. Stop the test after all base fluids have achieved a plateau of gas production. At termination, base fluid concentrations can be verified in the terminated samples by

extraction and GC anal ys is according to Section 5.8 . **5.4 Concentration Verification Chemical Analyses**  Because of the difficulty of homogeneousl y mixing base fluid with sediment, it is important to demonstrate that the base fluid is evenly mixed within the sediment sea water slurry that was added to each bottle. Of the seven serum bottles set up for each test or control condition, three are randomly

selected for concentration verif ication anal ys es. These should be immediately placed at 4  C and a sample of sediment from each bottle should be analyzed for base fluid content as soon as possible. The coefficient of variation (CV) for the replicate samples must be less than 20%. The resu lts should show recovery of at least 70% of the spiked base fluid. Use an appropriate anal yt ical procedure described in Section 5.8 to perform the extractions and analy ses. If any set of sediments fail the criteria for concentr ation verification, then the corrective action for that set of sediments is also outlined in Section 5.8 . The nominal concentrations and the measured concentrations from the three bottles selected for concentration verification should be reported for the initial test concentrations. The coefficient of variation (CV) for the replicate samples must be less than 20%. If base fluid content results are5 - 7

not within the 20% CV limit, the test must be stopped and restarted with adequatel y mixed sediment. **5.5 Gas Monitoring Procedures**  Biodegradation is measured by total gas as specified in ISO 11734:1995. Methane production can also be tracked and is described in Section 5.7 . 5.5.1 Total Gas Monitoring Procedures

Bottles should be brought to room temperature before readings are taken . The bottles are observed to confirm that the resazurin has not oxidized to pink or blue. Total gas production in the culture bottles should be measured using a pressure transducer (one sourc e is Biotech International). The pressure readings from test and control cultures are evaluated against a calibration curve created by analy zing the pressure created by known additions of gas to bottles established identically to the culture bottles. Bottl es used for the standard curve contain 75 mL of water, and are sealed with the same rubber septa and crimp cap seals used for the bottles containing sediment. After the bottles used in the standard curve have been sealed, a sy ringe needle inserted through the septa is used to equilibrate the pressure inside the bottles to the outside atmosphere. The s yringe needle is removed and known volumes of air are injected into the headspace of the bottles. Pressure readings provide a standard curve relating the volum e of gas injected into the bottles and headspace pressure. No less than three points may

be used to generate the standard curve. A ty pical standard curve may use 0, 1, 5, 10, 20 and 40 ml of gas added to the standard curve bottles. The room temperature and barometric pressure (to two digits) should be recorded at the time of sampling. One option for the barometer is Fisher Part #02 - 400 or 02 - 401. Gas production b y the sediment is expressed in terms of the volume (mL) of gas at standard temperature (0°C = 27 3°K) and pressure (1 atm = 30 inches of Hg) using Eq. 5 - 16. [ 5 - 16 ] Where : V 2 = Volume of gas production at standard temperature and pressure P 1 = Barometric pressure on day of sampling (inches of Hg) V 1 = Volume of gas measured on day of sampling (mL) T 2 = Standard temperature = 273 ° K T 1 = Temperature on day of sampling ( ° C + 273 = ° K) P 2 = Standard pressure = 30 inches Hg An estimate can be made of the total volume of ana erobic gas that will be produced in the bottles. The gas production measured for each base fluid can be expressed as a percent of predicted total anaerobic gas production. V 2 = P 1 × V 1 × T 2

T 1 × P 25 - 8 5.5.1.1 Calculate the total amount of carbon in the form of the base fluid present

in each b ottle Each bottle is to contain 30 g dry weight sediment. The base fluid concentration is 2,000 mg carbon/kg dry weight sediment. Therefore: 2,000 mg carbon/kg sediment × (30 g ÷ 1,000) = 60 mg carbon per bottle [ 5 - 17 ] 5.5.1.2 Theory

states that anaerobic microorganisms will convert 1 mole of carbon substrate into 1 mole of total anaerobic gas production Calculate the number of moles of carbon in each bottle. The molecular weight of carbon is 12 (i.e., 1 mole of ca rbon = 12 g). Therefore, the number of moles of carbon in each bottle can be calculated. [ 5 - 18 ] 5.5.1.3 Calculate the predicted volume of anaerobic gas

One mole of gas equals 22.4 L(at standard temperature and pressure), therefore, 0.005 moles × 22.4 L= 0.112L(or 112 mL total gas production) [ 5 - 19 ] 5.5.2 Gas Venting

If the pressure in the serum bottle is too great for the pressure transdu cer or sy ringe, some of the excess gas must be wasted. The best method to do this is to vent the excess gas right after measurement. To do this, remove the barrel from a 10 - mL syringe and fill it 1/3 full with water. This is then inserted into the bottle through the stopper using a small diameter (high gauge) needle. The excess pressure is allowed to vent through the water until the bubbles stop. This allows equalization of the pressure inside the bottle to atmospheric without introducing oxygen. The amount of gas vented (which is equal to the volume determined that day) must be kept track of each time the bottles are vented. A simple way to do this in a spreadsheet format is to have a separate column in which cumulative vented gas is tabulated. Each time th e volume of gas in the cultures is analyzed, the total gas produced is equal to the gas in the culture at that time plus the total of the vented gas. To keep track of the methane lost in the venting procedure, multiply the amount of gas vented each time b y the corrected % methane determined on that day . The answer gives the volume of methane wasted. This must be added into the cumulative totals similarly to the total gas additions. 60 mg carbon per bottle/1,000 = 0.005 moles carbon

12 g/mole5 - 9

**5.6 Test Acceptability and Interpretation**  5.6.1 Test Acceptability

At day 275 or when gas production has plateaued, whichever is first, the controls are evaluated to confirm that the test has been performed appropriately. In order for this modification of the closed bottle biodegradation test to be considered acceptable, all the controls mu st meet the biodegradation levels indicated in Table 5 - 1 . The intermediate control hexadecene must produce at least 30% of the theoretical gas production. This level may be reexamined after two years and more data has been generat ed. **Table 5**  **- 1**  **. Test Acceptability Criteria Concentration**  **Percent Biodegradability as a Function of Gas Measurement**

Positive control Squalane negative control Hexadecene intermediate control 2,000 mg carbon

/kg ≥60% theoretical ≤5% theoretical ≥30% theoretical 5.6.2 Interpretation

In order for a fluid to pass the closed bottle test, the biodegradation of the base fluid as indicated b y the total amount of total gas (or methane) generated once gas production has platea

ued (or at the end of 275 days, which ever is first) must be greater than or equal to the volume of gas (or methane) produced b y the reference standard (internal elefin or ester). The method for evaluating the data to determine whether a fluid has passed the biodegradation test must use the equations: [ 5 - 20 ] Where : NAF = S tock base fluid being tested for compliance Reference fluid = C 16 –C 18 internal olefin or C 1 2 –C 1 4 or C 8 es ter reference fluid **5.7 Methane Measurement**  5.7.1 Methane Monitoring Procedures

The use of total gas production alone may result in an underestimation of the actual metabolism occurring since CO 2 is slightly soluble in water. An acceptable alternative method is to monitor methane production and total gas production. This is easily done using GC anal ys is. A direct injection of headspace gases can be made into a GC using almost any

packed or capillary

column with an FID detector. Unless volatile fuels or solvents are present in the test material or the inocula, the only component of the headspace gas that can be detected using an FID detector is methane. The percent % Theoretical gas production of reference fluid ≤ 1.0 % Theoretical gas productio n of NAF5 - 10 methane in the headspace gas is determined b y comparing the response of the sample injections to the response from injections of known percent methane standards. The percent methane is corrected for water vapor saturation using Eq. 5 - 21 and then converted to a volume of dry methane using Eq. 5 - 22. [ 5 - 21 ] Where: D = The density of water vapor at saturation (g/m 3 , can be found in CRC Handbook of Chemistry and Physics) for the temperature of sampling. [ 5 - 22 ] Where: V CH4 = The volume of methane in the bottle S = Volume of excess gas production (measured with a pressure

transducer) V = Volume of the headspace in the culture bottle (total volume - liquid

phase) P = Barometric pressure (mm Hg, meas ured with barometer) T = Temperature (  C) P w = Vapor pressure of water at T (mm Hg, can be found in CRC

Handbook of Chemistry

and Phy sics) CH 4 = % methane in headspace gas (after correction for water vapor) The total volume of serum bottles sold as 125 mL bottles (Wheaton) is 154.8 mL . The volumes of methane produced are then compared to the volumes of methane in the controls to determine if a significant inhibition of methane production or a significant increase of methane production has been observ ed. Effective statistical anal ys es are important, as variability in the results is common due to the heterogeneity

of the inoculum’s source. It is also common to observe that the timing of the initiation of culture activity is not equal in all of the cultures. Expect a great variability

over the period when the cultures are active, some replicates will start sooner than others, but all of the replicates should eventuall y reach similar levels of base fluid degradation and methane production. 5.7.2 Expected Methane Production Calculations

The amount of methane expected can be calculated using the equation of Symons and Buswell (Eq. 5 - 23). In the case of complete mineralization, all of the carbon will appear as wither CO 2 or CH 4 , thus the total moles of gas produced will be equal to the total moles of carbon in the parent molecule. The use of the Buswell equation allows yo u to calculate the effects the redox potential will have on the distribution of the V CH4 (ml) = (S + V) × P

– P w × CH 4 × 273 T + 273 100 760 Corrected % CH 4 = % CH 4

1

– D × 22.4 L/mol 18 g/mol × 1,0005 - 11 products in methanogenic cultures. More reduced electron donors will allow the production of more methane, while more oxidized electron donors will cause a production of more carbon dioxide. C nH a O bN c S d + (n - a/4 - b/2 + 7c/4 + d/2) H 2 O → (n/2 - a/8+b/4 - 5c/8 + d/4) CO 2 +

(n/2 +a/8 - b/4 - 3c/8 - d/4) CH 4 + cNH 4 HCO 3 + dH 2 S [ 5 - 23 ] An example calculation of the expected methane volume in a culture fed 2 , 000 mg/kg hexadecene is as follows. The application of S ym ons and Buswell’ s equation reveals that hexadecene (C 16 H 32 ) will yield 4 moles of CO 2 and 12 moles of CH 4 . Assuming 30 g of dry

sediment are added to the bottles with 2,334 mg hexadecene/kg dry sediment ( i.e., equivalent to 2 , 000 mg carbon/kg dry sediment) the calculation is as follows. [ 5 - 24 ] By subtracting the average amount of methane in control bottles from the test bottles and then dividing b y the expected v olume an evaluation of the completion of the process may

be conducted. **5.8 Concentration Verification Analysis**  The Concentration Verification anal ys i s is required at the beginning of the test to ensure homogeneity

and confirm that the required amount of fluid was delivered to the sediments at the start of the test. 5.8.1 Three samples per fluid need to be anal yz ed and achieve ≤ 20% Coefficient of

Variability and an average of ≥ 70% to ≤ 120% of fluid delivered to sediment. 5.8.2 If a third party performs the anal ys is, then the laboratory should be capable of delivering the homogeneity data within seven day s, in order to identify any samples that do not meet the homogeneity requirement as quickly

as possible. 5.8.3 If one sediment/fluid set, out a multiple set batch of samples, fails these criteria, then

that one set of samples must be discarded and a fresh set of spiked sediment prepared, started, and anal yz ed to ensure homogeneity. The same stock sediment is used to prepare the replacement set(s). The remaining sets do not need to be re - mixed or restarted. 5.8.4 The re - mixed set(s) will need to be run the additional days as appropriate to ensure

that the total number of day s is the same for all sets of bottles, even though the specific day s are not aligned. 5.8.5 Re - mixing of bottle sets can be performed multiple times as a result of a failure of the

anal yt ical criteria, until the holding time for the stoc k sediment has expired (60 day s). If the problem set(s) has not fallen within the acceptable anal ytical criteria by then, it 12 mole CH 4 × 22.4 L × 1,000 ml × 1 mole hexadecene × 23 g

hexadecene × 0.03 kg = 84 (ml) mole hexadecene mole CH 4 L 224. 4 g hexadecene kg dry

soil culture5 - 12 must not be part of the batch of bottles run. If the problem batch is one of the controls, and those controls were not successfull y prepared when the sediment holding time expired, then the entire test must be restarted. **5.9 Program Quality Assurance**  **a nd Quality Control**  5.9.1 Calibration

5.9.1.1 All equipment / instrumentation will be calibrated in accordance with the

test method or the manufacture's i nstructions and may be scheduled or triggered . 5.9.1.2 Where possible, standards used in calibration will be traceable to a

nationally recognized standard (e.g., certified standard by NIST) . 5.9.1.3 All calibration activities will be documented and the records retained . 5.9.1.4 T he source, lot, batch number, and expiration date of all reagents used

with be documented and retained . 5.9.2 Maintenance

5.9.2.1 All equipment / instrumentation will be maintained in accordance with the

test method or the manufacture's instructions and may be scheduled or triggered . 5.9.2.2 All maintenance activities will be documented and the records retained . 5.9.3 Data Management and Handling

5.9.3.1 All primary

(raw) data will be correct, complete, without selective reporting, and will be maintained . 5.9.3.2 Hand - written data will be recorded in lab notebooks or electronically at the time of observation . 5.9.3.3 All hand - written records will be legible and amenable to reproduction by

electrostatic copiers . 5.9.3.4 All changes to data or other records will be made by :

a. U sing a single line to mark - through the erro neous entry (maintaining original data legibility) b. Write the revision c. Initial, date, and provide revision code ( see attached or laboratory ’s equivalent)5 - 13 5.9.3.5 All data entry , transcriptions, and calculations will be verified b y a

qualified person . a. V erification w ill be documented by initials of verifier and date 5.9.3.6 Procedures will be in place to address data management procedures used

(at minimum): a. Significant figures b. Rounding practices c. Id entification of outliers in data series d. Required statistics 5.9.4 Document Control

5.9.4.1 Al l technical procedures, methods, work instructions, standard operating

procedures must be documented and approved b y laboratory management prior to the implementation . 5.9.4.2 All primary

data will be maintained by the contractor for a minimum of five (5) ye ars . 5.9.5 P ersonnel and Training

5.9.5.1 Only

qualified personnel shall perform laboratory activities . 5.9.5.2 Records of staff training and experience will be available. This will

include initial and refresher training (as appropriate) . 5.9.6 Test Performance

5.9.6.1 All testing will done in acc ordance with the specified test methods . 5.9.6.2 Receipt, arrival condition, storage conditions, dispersal, and accountability

of the test article will be documented and maintained . 5.9.6.3 Receipt or production, arrival or initial condition, storage conditions,

dispersal , and accountability of the test matrix (e.g., sediment or artificial seawater) will be documented and maintained . 5.9.6.4 Source, receipt, arrival condition, storage conditions, dispersal, and

accountability

of the test organisms (including inoculum) will be documented and maintained . 5.9.6.5 Actual concentrations administered at each treatment level will be verified

by appropriate methodologies .5 - 14 5.9.6.6 Any

data originating at a different laboratory will be identified and the laboratory

full y referenced in the final rep ort. 5.9.7 The following references identify anal ytical methods that have historicall y been successful for achieving the anal ytical quality criteria. 5.9.7.1 Continental Shelf Associates report 1998. Joint EPA/Industry screening survey to assess the deposition of drill cuttings and associated s ynthetic based mud on the seabed of the Louisiana continental shelf, Gulf of Mexico. Analy sis by

Charlie Henry

report Number IES/RCAT97 - 36 GC FID and GC/MS. 5.9.7.2 EPA Method 3550 for extraction with EPA Method 8015 for GC - FID. 5.9.7.3 Webster, L ; Mackie, P.R.; Hird, S.J.; Munro, P.D.; Brown, N.A. and

Moffatt, C.F. (1997) Development of Anal ytical Methods for the Determination of S ynthetic Mud Base Fluids in Marine Sediments Analyst 122:1485 - 1490. 5.9.7.4 Munro, P.D., B Croce, C.F. Moffet, N.A Brown, A.D. McIntosh , S.J.

Hird, R.M. Stagg. 1998. Solid - phase test for comparison for degradation rates of s ynthetic mud base fluids used in the off shore drilling industry. Environ. Toxicol. Chem. 17:1951 - 1959.6 - 1

**6. D**  **ETERMINATION OF C**  **RUDE O**  **IL C**  **ONTAMINATION IN N**  **ON -** **A QUEOUS**  **D RIL**  **LING F**  **LUIDS BY**  **G AS**  **C HROMATOGRAPHY** **/M ASS**  **S PECTROMETRY**  **(GC/MS) (EPA**  **M ETHOD**  **1655) 6.1**  **Scope and Application** 6.1.1 This method determines crude (formation) oil contamination, or other petroleum oil

contamination, in non - aqueous drilling fluids (NAFs) b y comparing the gas chromatograph y/mass spectrometry (GC/MS) fingerprint scan and extracted ion scans of the test sample to that of an uncontaminated sample. 6.1.2 This method can be used for monitoring oil contamination of NAFs or monitoring oil

contamination of the base fluid us ed in the NAF formulations. 6.1.3 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. 6.1.4 The gas chromatography /mass spectrometry

portions of this method are restricted to use by , or under the supervision of anal ys ts experienced in the use of GC/MS and in the interpretation of gas chromatograms and extracted ion scans. Each laboratory that uses this method must gen erate acceptable results using the procedures described in Sections 6.7 , 6.9.2 , and 6.12 . **6.2 Summary of Method**  6.2.1 Analy sis of NAF for crude oil contamination is a step - wise process. The analy st first

performs a qualitative assessment of the presence or absence of crude oil in the sample. If crude oil is detected during this qualitative assessment, the anal ys t must perform a quantitative analy sis of the crude oil concentration. 6.2.2 A sample of NAF is centrifuged to obtain a solids free supernate. 6.2.3 The test sample is prepared by removing an aliquot of the solids free supernate, spiking it with internal standard, and anal yz ing it using GC/MS techniques. The components are separated by the gas chromatograph and detected by the mass spectrometer. 6.2.4 Qualitative identification of crude oil contamination is performed b y comparing the

Total I on Chromatograph (TI C) scans and Extracted I on Profile (EIP) scans of test sample to that of uncontaminat ed base fluids, and examining the profiles for chromatographic signatures diagnostic of oil contamination. 6.2.5 The presence or absence of crude oil contamination observed in the full scan profiles

and selected extracted ion profiles determines further sample q uantitation and reporting requirements. 6.2.6 If crude oil is detected in the qualitative anal ys is, quantitative anal ys is must be

performed b y calibrating the GC/MS using a designated NAF spiked with known concentrations of a designated oil.6 - 2

6.2.7 Quality

is assured through reproducible calibration and testing of GC/MS sy stem and through anal ys is of quality control samples. **6.3 Definitions**  6.3.1 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 sy nthetic material such as olefins and vegetable esters). 6.3.2 TI C

—Total Ion Chromatograph. 6.3.3 EIP

—Extracted Ion Profile. 6.3.4 TCB

— 1,3,5 - trichlorobenzene is used as the internal standard in this method. 6.3.5 SPTM

— System Performance Test Mix standards are used to establish retention times

and monitor detection levels. **6.4 Interferences and**  **Limitations** 6.4.1 Solvents, reagents, glassware, and other sample processing hardware may yield artifacts and/or elevated baselines causing misinterpretation of chromatograms. 6.4.2 All Materials used in the anal ys is shall be demonstrated to be free from interferences

by running method blanks. Specific selection of reagents and purification of solvents by distillation in all - glass sy stems may be required. 6.4.3 Glassware shall be cleane d by rinsing with solvent and baking at 400 °C for a minimum of 1 hour. 6.4.4 Interferences may vary from source to source, depending on the diversity of the samples being tested. 6.4.5 Variations in and additions of base fluids and/or drilling fluid additives (emulsif iers, dispersants, fluid loss control agents, etc.) might also cause interferences and misinterpretation of chromatograms. 6.4.6 Difference in light crude oils, medium crude oils, and heav y crude oils will result in

different responses and thus different interpretation of scans and calculated percentages. **6.5 Safety**  6.5.1 The toxicity

or carcinogenicity

of each reagent used in this method has not been precisel y determined; however each chemical shall be treated as a potential health hazard. Exposure to these chemicals should be reduced to the lowest possible level. 6.5.2 Unknown samples may contain high concentration of volatile toxic compounds. Sample containers should be opened in a hood and handled with gloves to prevent6 - 3 exposure. In addition, all sample preparation should be conducted in a fume hood to limit the potential exposure to harmful contaminates. 6.5.3 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 anal ys es. Additional references to laboratory safety can b e found in Section 6.16 , References 1 through 3. 6.5.4 NAF base fluids may cause skin irritation, protective gloves are recommended while handling these samples. **6.6 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 . 6.6.1 Equipment for glassware cleaning.

6.6.1.1 Laboratory

sink with overhead fume hood. 6.6.1.2 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 ., Santa Fe Springs, CA B31H or X31TS or equivalent). 6.6.2 Equipment for sample preparation.

6.6.2.1 Laboratory

fume hood. 6.6.2.2 Analy

tical balance

—Capable of weighing 0.1 mg. 6.6.2.3 Glassware.

a. Disposable pipettes

—Pasteur, 150 mm long b y 5 mm ID (Fisher Scientific 13

– 678

– 6A, or equ ivalent) baked at 400 °C for a minimum of 1 hour. b. Glass volumetric pipettes or gas tight s yringes

— 1.0 - mL±1% and 0.5 - mL±1%. c. Volumetric flasks

—Glass, class A, 10 - mL , 50 - mLand 100 - mL . d. Sample vials

—Glass, 1 - to 3 - mL(baked at 400 °C for a minimum of 1 hour) w ith PTFE - lined screw or crimp cap. e. Centrifuge and centrifuge tubes

—Centrifuge capable of 10,000 rpm, or better, (International Equipment Co., IEC Centra MP4 or equivalent)6 - 4 and 50 - mLcentrifuge tubes (Nalgene, Ultratube, Thin Wall 25×89 mm, #3410

–2539). 6.6.3 Gas Chromatograph/Mass Spectrometer (GC/MS):

6.6.3.1 Gas Chromatograph

— An anal ytical sy stem complete with a temperature programmable gas chromatograph suitable for split/splitless injection and all required accessories, including s yringes, anal yt ical columns, and gas es. a. Column

— 30 m (or 60 m) × 0.32 mm ID (or 0.25 mm ID) 1 μm film thickness (or 0.25 μm film thickness) silicone - coated fused - silica capillary column (J&W Scientific DB

– 5 or equivalent). 6.6.3.2 Mass Spectrometer

—Capable of scanning from 35 to 6 00 amu every 1 sec o r less, using 70 volts (nominal) electron energy in the electron impact ionization mode (Hewlett Packard 5970MS or comparable). 6.6.3.3 GC/MS interface

—the interface is a capillary- direct interface from the GC

to the MS. 6.6.3.4 Data s ys tem

— A computer s ys tem must be interfaced to the mass spectrometer. The s ys tem must allow the continuous acquisition and storage on machine - readable media of all mass spectra obtained throughout the duration of the chromatographic program. The computer must have software that can search any GC/MS data file for ions of a specific mass and that can plot such ion abundance versus retention time or scan number. This ty

pe of plot is defined as an Extracted I on Current Profile (EIP). Software must also be available that allows integrating the abund ance in any total ion chromatogram (TIC) or EIP between specified retention time or scan - number limits. It is advisable that the most recent version of the EPA/NIST Mass Spectral Library be available. **6.7 Reagents**  **and Standards** 6.7.1 Methylene chloride

—Pesticide gra de or equivalent. Use when necessary for sample dilution. 6.7.2 Standards

—Prepare from pure individual standard materials or purchase as certified

solutions. I f compound purity is 96% or greater, the weight may be used without correction to compute the concentration of the standard. 6.7.2.1 Crude Oil Reference

— Obtain a sample of a crude oil with a known API

gravity . This oil shall be used in the calibration procedures. 6.7.2.2 Sy

nthetic Base Fluid

—Obtain a sample of clean internal olefin (IO) Lab drilling fluid (as sent from the supplier

— has not been circulated downhole). This drilling fluid shall be used in the calibration procedures. 6.7.2.3 Internal standard

—Prepare a 0.01 g/mL solution of 1,3,5 - trichlorobenzene (TCB). Dissolve 1.0 g of TCB in methylene chloride and dilute to volume6 - 5 i n a 100 - mLvolumetric flask. Stopper, vortex, and transfer the solution to a 150 - mLbottle with PTFE - lined cap. Label appropriately , and store at

- 5 °C to 20 °C. Mark the level of the meniscus on the bottle to detect solvent loss. 6.7.2.4 GC/MS system performance te st mix (SPTM) standards

—The SPTM

standards shall contain octane, decane, dodecane, tetradecane, tetradecene, toluene, eth ylbenzene, 1,2,4 - trimethylbenzene, 1 - methylnaphthalene and 1,3 - dimethylnaphthalene. These compounds can be purchased individually or ob tained as a mixture (i.e. , Supelco, Catalog No. 4

–7300). Prepare a high concentration of the SPTM standard at 62.5 mg/mLin methylene chloride. Prepare a medium concentration SPTM standard at 1.25 mg/mL by transferring 1.0 mLof the 62.5 mg/mL solution int o a 50 mL volumetric flask and diluting to the mark with methylene chloride. Finall y, prepare a low concentration SPTM standard at 0.125 mg/mLby transferring 1.0 mLof the 1.25 mg/mL solution into a 10 - mLvolumetric flask and diluting to the mark with methylene chloride. 6.7.2.5 Crude oil/drilling fluid calibration standards

—Prepare a 4 - point crude

oil/drilling fluid calibration at concentrations of 0% (no spike

—clean drilling fluid), 0.5%, 1.0%, and 2.0% b y weight according to the procedures outlined in this section using the Reference Crude Oil: a. Label 4 jars with the following identification: Jar 1

—0%Ref - IO Lab, Jar 2

—0.5%Ref

- IO Lab, Jar 3

— 1%Ref

- IO Lab, and Jar 4

—2%RefIO Lab. b. Weigh 4, 50 - g aliquots of well mixed I O Lab drilling fluid into each of the 4 jars. c. Add Ref

erence Oil at 0.5%, 1.0%, and 2.0% b y weight to jars 2, 3, and 4 respectivel y. Jar 1 shall not be spiked with Reference Oil in order to retain a “0%” oil concentration. d. Thoroughl y mix the contents of each of the 4 jars, using clean glass stirring rods. e. Transfer (weigh) a 30 - g aliquot from Jar 1 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 directl y into a tared and appropriate ly 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 Sectio n 7.2.3 ), cap with a Teflon lined crimp cap, and vortex for ca. 10 sec. f. Repeat step 6.7.2.5(e) except use an aliquot from Jar 2. g. Repeat step 6.7.2.5(e) except use an aliquot from Jar 3.6 - 6 h. Repeat step 6.7.2.5(e) except use an aliquot from Jar 4. i. These 4 crude/oil drilling fluid calibration standards are now used for qualitative and quantitative GC/MS analy sis. 6.7.2.6 Precision and recovery standard (mid level crude oil/drilling fluid calibration standard)

—Prepare a mid point crude oil/ drilling fluid calibration using IO Lab drilling fluid and Reference Oil at a concentration of 1.0% b y weight. Prepare this standard according to the procedures outlined in Section 6.7.2.5a through 6.7.2.5e , with the exception that only

“Jar 3” needs to be prepared. Remove and spike with internal standard, as m any 0.5 - g aliquots as needed to complete the GC/MS analy sis ( see Section 6.11.6

— bracketing authentic samples every 12 hours with precision and recovery standard) and the initial demonstration exercise described in Section 6.9.2 . 6.7.2.7 Stability

of standards a. When not used, standards shall be s tored in the dark, at - 5 to - 20 °C in screw - capped vials with PTFE - lined lids. Place a mark on the vial at the level of the solution so that solvent loss by evaporation can be detected. Bring the vial to room temperature prior to use. b. Solutions used for quantitative purposes shall be analyzed within 48 hours of preparation and on a monthly basis thereafter for signs of degradation. A standard shall remain acceptable if the peak area remains within ±15% of the area obtained in the initial analy sis of the standard. **6.8 Sample**  **Collection Preservation and Storage**  6.8.1 Collect NAF and base fluid samples in 100 - to 200 - mLglass bottles with PTFE - or

aluminum foil lined caps. 6.8.2 Samples col lected in the field shall be stored refrigerated until time of preparation. 6.8.3 Sample and extract holding times for this method have not yet been established.

However, based on initial experience with the method, samples should be analyzed within seven to ten day s of collection and extracts should be anal yz ed within seven day s of preparation. 6.8.4 After completion of GC/MS analy sis, extracts shall be refrigerated at 4 °C until further

notification of sample disposal. **6.9 Quality Control**  6.9.1 Each laboratory that uses this me thod is required to operate a formal quality assurance program ( Section 6.16 , Reference 4 ). The minimum requirements of this program shall consist of an initial demonstration of laboratory capability, and ongoing anal ys is of st andards, and blanks as a test of continued performance, anal yses of6 - 7 spiked samples to assess accuracy and anal ys is of duplicates to assess precision. Laboratory

performance shall be compared to established performance criteria to determine if the results o f anal ys es meet the performance characteristics of the method. 6.9.1.1 The anal ys t shall make an initial demonstration of the ability to generate acceptable accuracy

and precision with this method. This ability shall be established as described in Section 6.9.2 . 6.9.1.2 The anal ys t is permitted to modify this method to improve separations or lower the cost of measurements, provided all performance requirements are met. Each time a modification is made to the method, the anal ys t is required to repeat the calibration ( Section 6.10.4 ) and to repeat the initial demonstration procedure described in Section 6.9.2 . 6.9.1.3 Analy ses of blanks are required t o demonstrate freedom from

contamination. The procedures and criteria for analy sis of a blank are described in Section 6.9.3 . 6.9.1.4 Analy sis of a matrix spike sample is required to demonstrate method

accuracy . The pro cedure and QC criteria for spiking are described in Section 6.9.4 . 6.9.1.5 Analy sis of a duplicate field sample is required to demonstrate method

precision. The procedure and QC criteria for duplicates are described in Section 6.9.5 . 6.9.1.6 Analy sis of a sample of the clean NAF(s) (as sent from the supplier

— has not been circulated downhole) used in the drilling operations is required. 6.9.1.7 The laboratory shall, on an ongoing basis, demons trate through calibration verification and the anal ysis of the precision and recovery standard ( Section 6.7.2.6 ) that the anal ys is sy stem is in control. These procedures are described in Section 6.11.6 . 6.9.1.8 The laboratory shall maintain records to define the quality of data that is generated. 6.9.2 Initial precision and accuracy

—The initial precision and recovery test shall be performed using the precision and recovery standard (1% b y weight Reference Oil in IO L ab drilling fluid). The laboratory shall generate acceptable precision and recovery by performing the following operations. 6.9.2.1 Prepare four separate aliquots of the precision and recovery standard using the procedure outlin ed in Section 6.7.2.6 . Analyze these aliquots using the procedures outlined in Section 6.11 .6 - 8 6.9.2.2 Using the results of the set of four anal ys es, compute the average recov ery

(X) in weight percent and the standard deviation of the recovery(s) for each sample. 6.9.2.3 If s and X meet the acceptance criteria of 80% to 110%, sy stem

performance is acceptable and analy sis of samples may begin. If, however, s exceeds the precision limit or X falls outside the range for accuracy , sy stem performance is unacceptable. In this event, review this method, correct the problem, and repeat the test. 6.9.2.4 Accuracy

and precision

—The average percent recovery (P) and the standard deviation of the percent re covery (Sp) Express the accuracy assessment as a percent recovery interval from P

–2Spto P+2Sp. For example, if P=90% and Sp=10% for four anal ys es of crude oil in NAF, the accuracy interval is expressed as 70% to 110%. Update the accuracy assessment on a re gular basis. 6.9.3 Blanks

—Rinse glassware and centrifuge tubes used in the method with 30 mLof

methylene chloride, remove a 0.5 - g aliquot of the solvent, spike it with the 500 μL of the internal standard solution ( Section 6.7.2.3 ) and anal yz e a 1 - μLaliquot of the blank sample using the procedure in Section 6.11 . Compute results per Section 6.12 . 6.9.4 Matrix spike sample

—Prepare a matrix spike sample according to procedure outlined

in Section 6.7.2.6 . Analyze the sample and calculate the concentration (% oil) in the drilling fluid and % recovery of oil from the spiked drilling fluid using th e methods described in Sections 6.11 and 6.12 . 6.9.5 Duplicates

—

A duplicate field sample shall be prepared and anal yz ed according to Section 6.11 . The relative percent difference (RPD) of the calculated concentrations shall be less than 15%. 6.9.5.1 Analyze each of the duplicates per the procedure in Section 6.11 and

compute the results per Sec tion 6.12 . 6.9.5.2 Calculate the relative percent difference (RPD) between the two results

per the followi ng equation: [ 6 - 1 ] Where: D 1 = C oncentration of crude oil in the sample ; and D 2 = Concentration of crude oil in the duplicate sample. 6.9.5.3 If the RPD criteria are not met, the anal ytical system shall be judged to be

out of control, and the problem must be immediately identified and correcte d, and the sample batch re - anal yz ed.

RPD = │D 1 – D 2 │ × 100 [(D 1 + D 2 ) /2 ]6 - 9

6.9.6 A clean NAF sample shall be prepared and anal yz ed according to Section 6.11 .

Ultimately

the oil - equivalent concentration from the TI C or EIP signal measured in the clean NAF sample shall be subtracted from the correspon ding authentic field samples in order to calculate the true contaminant concentration (% oil) in the field samples ( see Section 6.12 ). 6.9.7 The specifications contained in this method can be met if the apparatus used is

calibrated properl y, and maintained in a calibrated state. The standards used for initial precision and recovery

( Section 6.9.2 ) and ongoing precision and recovery ( Section 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 anal ys es given in this method. 6.9.8 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. **6.10 Calibration**  6.10.1 Establish gas chromatographic/mass spectrometer operating conditions given in Table

6 - 1 . Perform the GC/MS sy stem hardware - tune as outlined by the manufacture. The gas chromatograph shall be calibrated using the internal standard technique. Note: Bec ause 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 Table 6 - 2 are met. **Table 6**  **- 1**  **. Gas Chromatograph/Mass Spectrometer (GC/MS) Operation Conditions**  **Param eter**  **Setting** Injection po rt 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 .6 - 10 **Table 6**  **- 2**  **. Approximate Retention Time for Compounds**  **Compound Approxim**  **ate retention time (m inutes)**  Toluene 5.6 Octane, n−C 8 7.2 Ethylbenzene 10.3 1,2,4 - Trimethylbenzene 16.0 Decane, −C 10 16.1 TCB (Intern al Standard) 21.3 Dodecane, −C 12 22.9 1 - Methylnaphthalene 26.7 1 - Tetradecene 28.4 Tetradecane, −C 14 28.7 1,3 - Dimethylnaphthalene 29.7 6.10.2 Internal standard calibration procedure

— 1,3,5 - trichlorobenzene (TCB) has been

shown to be free of interferences fro m diesel and crude oils and is a suitable internal standard. 6.10.3 The sy stem performance test mix standards prepared in Section 6.7.2.4 shall be used

to establish retention times and establish qualitative detection l imits. 6.10.3.1 Spike a 500 - mLaliquot of the 1.25 mg/mL SPTM standard with 500 μL

of the TCB internal standard solution. 6.10.3.2 Inject 1.0 μLof 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 ty pical retention times shown in Table 6 - 2 above . Extracted ion scans for m/z 91 and 105 showed a maximum abundance of 400,000. 6.10.3.3 Spike a 500 - mLaliquot of the 0.125 mg/mL SPTM st andard with 500 μL

of the TCB internal standard solution. 6.10.3.4 Inject 1.0 μLof 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. 6.10.4 GC/MS crude oil/drilling fluid calibration

—There are two methods of quantification: Total Area Integration (C 8 –C 13 ) and EIP Area Integration using m/z's 91 an d 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 calibration6 - 11 standards prepared in Section 6.7.2.5 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. 6.10.4.1 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 C 8 to C 13 . Obtain the TI C area of the internal standard (TCB). Subtract the TCB area from the C 8 –C 13 area to obtain the true C 8 –C 13 area. Using the C 8 –C 13 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 b e greater than or equal to 0.998. Some sy nthetic fluids might have peaks that elute in the window and would interfere with the anal ys is. In this case the integration window can be shifted to other areas of scan where there are no interfering peaks from the sy nthetic base fluid. 6.10.4.2 EIP Area Integration

—For each of the four calibration standards generate Extracted I on Profiles (EIPs) for m/z 91 and 105. Using straight baseline integration techniques, obtain the following EIP areas: a. 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. b. For m/z 105 integrate the area under the curve from approximately 10.5 minutes to 26.5 minutes. c. Obtain the internal standard area from the TCB in each of the four calibration standards, using m/z 180. d. Using the E IP 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. e. 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. **6.11 Procedure**  6.11.1 Sample Preparation

6.11.1.1 Mix the authentic field sample (drilling fluid) well. Transfer (weigh) a 30 -

g aliquot of the sample to a labeled centrifuge tube.6 - 12 6.11.1.2 Centrifuge the aliquot for a minimum o f 15 min at approximately 15,000 rpm, in order to obtain a solids free supernate. 6.11.1.3 Weigh 0.5 g of the supernate directl y into a tared and appropriatel y

labeled GC straight vial. 6.11.1.4 Spike the 0.5 - g supernate with 500 μLof the 0.01g/mL 1,3,5 -

trichlorobenzene internal standard solution ( see Section 6.7.2.3 ), cap with a Teflon lined crimp cap, and vortex for ca. 10 sec. 6.11.1.5 The sample is ready for GC/MS analysis. 6.11.2 Gas Chromatograph y

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 Table 6 - 2 . Other columns, chromatographic conditions, or detectors may be used if initial pre cision and accuracy

requirements ( Section 6.9.2 ) are met. The s ys tem shall be calibrated according to the procedures outlined in Section 6.10 , and verified every 12 hours according to Section 6.11.6 . 6.11.2.1 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 6.9.3 ), 1 matrix spike sample ( Section 6.9.4 ), and 1 duplicate field sample ( 6.9.5 ), and a prepared sample of the corresponding clean NAF used in the drilling process. 6.11.2.2 An anal yt ical sequence shall be anal yz ed on the GC/MS where the 3

SPTM standards ( Section 6.7.2.4 ) containing internal standard are anal yz ed first, followed by analysis of the four GC/MS crude oil/drilling fluid calibration stan dards ( Section 6.7.2.5 ), anal ysis of the blank, matrix spike sample, the duplicate sample, the clean NAF sample, followed by the authentic samples. 6.11.2.3 Samples requiring dilution due to excessive signal shall be diluted using

methylene chloride. 6.11.2.4 Inject 1.0 μLof the test sample or standard into the GC, using the

conditions in Table 6 - 1 . 6.11.2.5 Begin data collection and the temperature program at the time of injection. 6.11.2.6 Obtain a TIC and EIP fingerpri nt scans of the sample ( Table 6 - 3 ). 6.11.2.7 If the area of the C 8 to C 13 peaks exceeds the calibration range of the

sy stem, dilute a fresh aliquot of the test sample weighing 0.50 - g and re anal yz e.6 - 13 6.11.2.8 Determine the C 8 to C 13 TI C area, the TC B 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 6.12 ). **Table 6**  **- 3**  **. Recommended Ion Mass Numbers**  **Selected I on**  **M ass**  **N umbers**  **Corresponding A**  **romatic C**  **om pounds**  **Typical R**  **etention T**  **im e (**  **M inutes)**  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 6.11.2.9 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. 6.11.3 Qualitative Identification

— See Section 6.17 of this method for sc hematic flowchart.

6.11.3.1 Qualitative identification shall be accomplished by comparison of the TIC and EIP area data from an authentic sample to the TI C and EIP area data from the calibration standards ( see Section 6.10.4 ). Crude oil shall be identified by

the p resence of C 10 to C 13 n - alkanes and corresponding target aromatics. 6.11.3.2 Using the calibration data, establish the identity of the C 8 to C 13 peaks in the chromatogram of the sample. Using the calibration data, establish the identity of any target aromatics pres ent on the extracted ion scans. 6.11.3.3 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 anal ys t shall weigh heavily in the determination of the presence of peaks at a signal - to - noise ratio of 3 or greater. 6.11.3.4 If the chromatogram shows n - alkanes from C 8 to C 13 and target aromatics

to be present, contamination by crude oil or diesel shall be suspected and quantitative anal ys is 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.6 - 14

6.11.4 Quantitative Identification

6.11.4.1 Determine the area of the peaks from C 8 to C 13 as outlined in the

calibration section ( Secti on 6.10.4.1 ). 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 TI C linear regression curve to determine approximate crude oil contamination . 6.11.4.2 Using the E IP s outlined in Section 6.10.4.2 , determine the presence of any

target aromatics. Using the integration techniques outlined in Section 6.10.4.2 , 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. 6.11.5 Complex Samples

6.11.5.1 The most common interferences in the determination of crude oil can be

from mineral oil, diesel oil, and proprietary additives in drilling fluids. 6.11.5.2 Mineral oil can typicall y be identified b y its lower target aromatic content,

and narrow range of strong peaks. 6.11.5.3 Diesel oil can typicall y be identified b y low amounts of n - alkanes from C 7

to C 9 , and the absence of n - alkanes greater than C 25 . 6.11.5.4 Crude oils can usuall y be distinguished by the presence of high aromatics,

increased intensities of C 8 to C 13 peaks, and/ or the presence of higher hydrocarbons of C 25 and greater (which may be difficult to see in some sy nthetic fluids at low contamination levels). a. Oil condensates from gas wells are low in molecular weight and will normally produce strong chromatographic peaks in the C 8 –C 13 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. b. Asphaltene crude oils with APIgravity < 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 C 8 to C 13 peaks. I f a sample of asphaltene crude from the formation is available, a calibration standard shall be prepared. 6.11.6 Sy stem and Laboratory Pe rformance 6.11.6.1 At the beginning of each 8 - hour shift during which anal ys es are

performed, GC crude oil/drilling fluid calibration and sy stem performance test mixes shall be verified. For these tests, anal ys is of the medium - level calibration standard (1 - % Reference Oil in IO Lab drilling fluid, and 1.256 - 15 mg/mLSPTM with internal standard) shall be used to verify all performance criteria. Adjustments and/or re - calibration (per Section 6.10 ) shall be performed until all p erformance criteria are met. Onl y after all performance criteria are met may samples and blanks be anal yz ed. 6.11.6.2 Inject 1.0 μLof the medium - level GC/MS crude oil/drilling fluid

calibration standard into the GC instrument according to the procedures in Section 6.11.2 . Verify

that the linear regression curves for both TIC area and EIP areas are still valid using this continuing calibration standard. 6.11.6.3 After this anal ys is is complete, inject 1.0 μLof the 1.25 mg/mLSPTM

(containing internal standard) into the GC instrument and verify the proper retention times are met ( see Table 6 - 2 ). 6.11.6.4 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 Table 6 - 2 . **6.12 Calculations**  The co ncentration of oil in NAFs drilling fluids shall be computed relative to peak areas between C 8 and C 13 (using the Total Area Integration method) or total peak areas from extracted ion profiles (using the Extracted I on 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 si gnal 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. 6.12.1 Total Area Integration Method

6.12.1.1 Using C 8 to C 13 TI C area, the TCB area in the clean NAF sample and the

TI C linear regression curve, compute the oil equivalent concentration of the C 8 to C 13 retention time range in the clean NAF. Note: The actual TI C area of the C 8 to C 13 is equal to the C 8 to C 13 area minus the area of the TCB. 6.12.1.2 Using the corresponding information for the authentic sample, compute

the oil equivalent concentration of the C 8 to C 13 retention time range in the authentic sample.6 - 16 6.12.1.3 Calculate the concentration (% oil) of oil in the sample by subtracting the oil equivalent concentr ation (% oil) found in the clean NAF from the oil equivalent concentration (% oil) found in the authentic sample. 6.12.2 EIP Area Integration Method

6.12.2.1 Using either m/z 91 or 105 EIP areas, the TCB area in the clean NAF

sample, and the appropriate EIP linear regress ion curve, compute the oil equivalent concentration of the in the clean NAF. 6.12.2.2 Using the corresponding information for the authentic sample, compute its

oil equivalent concentration. 6.12.2.3 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. **6.13 Method Performance**  6.13.1 Specification in this method are adopted from EPA Method 1663, Differentiation of

Diesel and Crude Oil by

GC/FID ( Section 6.16 , Reference 4 ). 6.13.2 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 anal ys is

— 6.2% **6.14 Pollution**  **Prevention** 6.14.1 The solvent used in this method poses little threat to the environment when recycled

and managed properl y. **6.15 Waste Management**  6.15.1 It is the laboratory's responsibility to c ompl y 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. 6.15.2 All authentic samples (drilling fluids) failing the RPE (fluorescence) test (indicated

by the presence of fluorescence) shall be retained and clas sified as contaminated samples. Treatment and ultimate fate of these samples is not outlined in this SOP. 6.15.3 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 Chemical6 - 17 Society's Department of Government Relations and Science Policy , 1155 16th Street NW, Washington, DC 20036. **6.16 References**  1. 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. 2. “OSHA Safety and Health Standards, Gene ral Industry [29 CFR 1910], Revised.” Occupational Safety and Health Administration, OSHA 2206. Washington, DC: January 1976. 3. “Handbook of Anal yt ical Quality Control in Water and Wastewater Laboratories.” USEPA, EMSSL - CI , EPA

– 600/4

–79

–019. Cincinnati, OH: March 1979. 4. “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 Anal ysis Division, Washington, DC: December 1992. 5. U.S. EPA. 2001. Effluent L imitations Guidelines and New Source Performance S tandards for the Oil and Gas Extraction Point Source Category . Federal Register, 66: 6849 (22 January

2001). 6. U.S. EPA. 2001. Effluent L imitations Gui delines and New Source Performance Standards for the Oil and Gas Extraction Point Source Category : Correction . Federal Register, 66: 30811 ( 8 June 2001).6 - 18

**6.17 S** **chematic Flowchart for**  **Qualitative Identification**

Yes No

No Yes

**Figure 6**  **- 1**  **. Schematic Flowc**  **hart for Qualitative Identification**

Prepare Sample for Analyses Section 6.11.1 GC/MS Analy ses Obtain the TI C for the Sample Section 6.11.2

Determine the C 8 to C 13 TI C Area for comparison to calibration standards Section 6.11.2.8 Obtain the EIP for m/z 91, m/z 105, and m/z 156 Section 6.11.2.6 C 8 to C 13 peaks seen on TI C

Peaks present for

Target Aromatics on EIP Crude oil contamination is below detection limit. Report not detected Section 6.11.3.3 Integrate peaks on the EIP for comparison to calibration to determine approximate crude oil contamination Section 6.11.4.27 - 1

**7. R** **EVERSE P**  **HASE E**  **XTRACTION (RPE)**  **M ETHOD FOR**  **D ETECTION OF**  **O IL**  **C ONTAMINATION IN**  **N ON**  **- A**  **QUEOUS D**  **RILLING F**  **LUIDS (NAF)**  **(EPA M**  **ETHOD 1670)**  **7.1 Scope and Application**  7.1.1 This method is used for determination of crude or formation oil, or other petroleum

oil contamination, in non - aqueous drilling fluids (NAFs). 7.1.2 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. 7.1.3 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. 7.1.4 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 conc entration of 1%. 7.1.5 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. 7.1.6 Each laboratory that uses this method must demonstrate the ability to generate acceptable results using the procedure in Section 7.9.2 . **7.2 Summary of Method**  7.2.1 An aliquot of drilling fluid is extracted using isopropyl alcohol. 7.2.2 The mixture is allow ed to settle and then filtered to separate out residual solids. 7.2.3 An aliquot of the filtered extract is charged onto a reverse phase extraction (RPE)

cartridge. 7.2.4 The cartridge is eluted with isopropyl alcohol. 7.2.5 Crude oil contaminates are retained on the cartri dge and their presence (or absence) is

detected based on observed fluorescence using a black light. **7.3 Definitions**  7.3.1 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, p araffinic oil, or sy nthetic material such as olefins and vegetable esters).7 - 2

**7.4 Interferences**  7.4.1 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. 7.4.2 All materials used in the anal ys is shall be demonstrated to be free from interferences

under the conditions of analy sis by running laboratory

reagent blanks as described in Section 7.9.5 . **7.5 Saf** 

**ety** 7.5.1 The toxicity

or carcinogenicity

of each reagent used in this method has not been precisel y determined; however, each chemical shall be treated as a potential health hazard. Exposure to these chemicals should be reduced to the lowest possible level. Mat erial Safety Data Sheets (MSDSs) shall be available for all reagents. 7.5.2 Isoprop ylalcohol is flammable and should be used in a well - ventilated area. 7.5.3 Unknown samples may contain high concentration of volatile toxic compounds. Sample containers should be opene d 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 preca utions used in the drilling fluid handling areas of the drilling rig. 7.5.4 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 regulat ions 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 anal ys es. Additional information on laboratory safety can be found in Section 7.16 , References 1 and 2 . **7.6 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 m aterials other than those specified here, but demonstration of equivalent performance that meets the requirements of this method is the responsibility of the laboratory . 7.6.1 Sampling equipment.

7.6.1.1 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. 7.6.2 Equipment for glassware cleaning.

7.6.2.1 Laboratory

sink.7 - 3 7.6.2.2 Oven

—Capable of maintaining a temperature within ±5°C in the range of 100

–250 °C. 7.6.3 Equipment for sample extraction.

7.6.3.1 Vials

—Glass, 25 mLand 4 mL , with Teflon - lin ed screw caps, baked at

200

–250 °C for 1

–

h minimum prior to use. 7.6.3.2 Gas - tight s yringes

—Glass, various sizes, 0.5 mLto 2.5 mL(if spiking of

drilling fluids with oils is to oc cur). 7.6.3.3 Auto pipetters

— various sizes, 0.1 mL , 0.5 mL, 1 to 5 mLdelivery , and 10 mLdelivery , with appropriate size disposable pipette tips, calibrated to within ±0.5%. 7.6.3.4 Glass stirring rod. 7.6.3.5 Vortex mixer. 7.6.3.6 Disposable sy ringes

—Plastic, 5 mL . 7.6.3.7 Teflon sy

ringe filter, 25 - mm, 0.45 μm pore size

— Acrodisc®CR Teflon (or equivalent). 7.6.3.8 Reverse Phase Extraction C 18 Cartridge

—Waters Sep - Pak®Plus, C 18

Cartridge, 360 mg of sorbent (or equivalent). 7.6.3.9 SPE vacuum manifold

— Supelco Brand, 12 unit (or equivalent). Used as support for cartridge/s yri nge assembl y only. Vacuum apparatus not required. 7.6.4 Equipment for fluorescence detection.

7.6.4.1 Black light

— UV Lamp, Model UVG 11, Mineral Light Lamp, Shortwave 254 nm, or L ongwave 365 nm, 15 volts, 60 Hz, 0.16 amps (or equivalent). 7.6.4.2 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 inch es from lamp. Cardboard flaps cut on top panel and side of front panel for sample viewing and sample cartridge introduction, respectively . 7.6.4.3 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.7 - 4

**7.7 Reagents and Standards**  7.7.1 Isoprop ylalcohol

— 99% purity . 7.7.2 NAF

—

Appropriate NAF as sent from the supplier (has not been circulated downhole). Use th e clean NAF corresponding to the NAF being used in the current drilling operation. 7.7.3 Standard crude oil

— NI ST SRM 1582 petroleum crude oil. **7.8 Sample Collection, Preservation, and Storage**  7.8.1 Collect approximately one liter of representative sample (NAF, which has b een circulated downhole) in a glass bottle or jar. Cover with a Teflon lined cap. To allow for a potential need to re - anal yz e and/or re - process the sample, it is recommended that a second sample aliquot be collected. 7.8.2 Label the sample appropriately . 7.8.3 All samples must be refrige rated at 0

–4 °C from the time of collection until extraction

(40 CFR Part 136, Table II). 7.8.4 All samples must be analyzed within 28 day s of the date and time of collection (40

CFR Part 136, Table II). **7.9 Quality Control**  7.9.1 Each laboratory that us es this method is required to operate a formal quality assurance program ( Section 7.16 , Reference 3). The minimum requirements of this program consist of an initial demonstration of laboratory capability , and ongoing anal ys es o f blanks and spiked duplicates to assess accuracy and precision and to demonstrate continued performance. Each field sample is analyzed in duplicate to demonstrate representativeness. 7.9.1.1 The anal ys t 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 7.9.2 . 7.9.1.2 Preparation and anal ys is of a set of spiked duplicate samples to document

accuracy and precision. The procedure for the preparation and anal ys is of these samples is described in Section 7.9.4 . 7.9.1.3 Analy ses of laboratory reagent blanks are required to demonstrate freedom from contamination. The procedure and cri teria for preparation and anal ys is of a reagent blank are described in Section 7.9.5 . 7.9.1.4 The laboratory shall maintain records to define the quality of the data that is generated.7 - 5 7.9.1.5 Accompanyi ng QC for the determination of oil in NAF is required per

anal yt ical batch. An analy tical batch is a set of samples extracted at the same time, to a maximum of 10 samples. Each analy tical batch of 10 or fewer samples must be accompanied b y a laboratory reagent blank ( Section 7.9.5 ), corresponding NAF reference blanks ( Section 7.9.6 ), a set of spiked duplicate samples blank (Section 7.9.4 ), and dupl icate anal ys is of each field sample. If greater than 10 samples are to be extracted at one time, the samples must be separated into anal ytical batches of 10 or fewer samples. 7.9.2 Initial demonstration of laboratory capability. To demonstrate the capability to perform the test, the analy st shall anal yz e two representative unused drilling fluids (e.g., internal olefin - based drilling fluid, vegetable ester- based drilling fluid), each prepared separatel y containing 0.1%, 1%, and 2% or a representative oil. Each dri lling fluid/concentration combination shall be anal yz ed 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 7.9.3 Sample duplicates.

7.9.3.1 The laboratory shall prepare and anal yz e ( Section 7.11.2 and 7.11.4 ) each authentic sample in duplicate, from a given sampling site or, if for compliance monitoring, from a given discharge. 7.9.3.2 The duplicate samples must be compared versus the prepared

corresponding NAF blank. 7.9.3.3 Prepare and analyze the duplicate samples according to procedures

outlined in Section 7.11 . 7.9.3.4 The results of the duplicate anal ys es 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, ens uring a well - mixed sample prior to extraction. Analyze the samples once again. 7.9.3.5 If different results are obtained for the duplicate a second time, the

anal yt ical sy stem is judged to be out of control and the problem shall be identified and corrected, and th e samples re - analyzed. 7.9.4 Spiked duplicates

—Laboratory prepared spiked duplicates are anal yz ed to demonstrate acceptable accuracy and precision. 7.9.4.1 Preparation and anal ys is of a set of spiked duplicate samples with each set

of no more than 10 field samples is re quired to demonstrate method accuracy and precision and to monitor matrix interferences (interferences7 - 6 caused b y 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 batc h analy sis) shall be spiked with 1% (by volume) of suitable reference crude oil and analyzed as field samples, as described in Section 7.11 . If no low - level drilling fluid is available, then the unused NAF can b e used as the drilling fluid sample. 7.9.5 Laboratory

reagent blanks

—Laboratory reagent blanks are anal yz ed to demonstrate freedom from contamination. 7.9.5.1 A reagent blank is prepared by passing 4 mL of the isopropyl alcohol through a Teflon s yringe filter and collec ting the filtrate in a 4 - mLglass vial. A Sep Pak® C 18 cartridge is then preconditioned with 3 mL of isopropyl alcohol. A 0.5 - mLaliquot of the filtered isopropyl alcohol is added to the s yringe barrel along with 3.0 mL of isopropyl alcohol. The solvent is passed through the preconditioned Sep Pak® cartridge. An additional 2 - mLof isopropyl alcohol is eluted through the cartridge. The cartridge is now considered the “reagent blank” cartridge and is ready for viewing (anal ys is). Check the reagent blank cartridge under the black light for fluorescence. If the isopropyl alcohol and filter are clean, no fluorescence will be observed. 7.9.5.2 If fluorescence is detected in the reagent blank cartridge, anal ys is 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. 7.9.6 NAF reference blanks

— NAF referenc e 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. 7.9.6.1 A NAF reference blank is prepared identicall y to the authentic samples.

Plac e a 0.1 mL aliquot of the “clean” NAF into a 25 - mLglass vial. Add 10 mLof isoprop ylalcohol 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 - mLsy ringe, draw up 4 mL o f the extract and filter it through a PTFE s yringe filter, collecting the filtrate in a 4 - mLglass vial. Precondition a Sep Pak® C 18 cartridge with 3 mLof isopropyl alcohol. Add a 0.5 - mLaliquot of the filtered extract to the sy ringe barrel along with 3.0 mLof isoprop yl alcohol. Pass the extract and solvent through the preconditioned Sep Pak ® cartridge. Pass an additional 2 - mLof isopropyl alcohol through the cartridge. The cartridge is now considered the NAF blank cartridge and is ready for viewing (anal ys is). 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 or7 - 7 absence of fluorescence in the authentic sample cartridge is determined relative to the NAF reference cartridge. 7.9.6.2 Positive control solution, equivalent to 1% crude oil contaminated mud

extract, is prepared b y dissolving 87 mg of standard crude oil into 10.00 mLof meth yl ene chloride. Then mix 40 μLof this solution into 10.00 mL of IPA. Transfer 0.5 mL of this solution into a preconditioned C 18 cartridge, followed b y 2 ml of IPA. **7.10 Calibration and Standardization**  7.10.1 Calibration and standardization methods are not employed for this procedure. **7.11 Procedure**  This method is a screening - level test. Precise and accurate results can be obtained only by strict adherence to all details. 7.11.1 Preparation of the anal yt ical batch.

7.11.1.1 Bring the anal ytical batch of samples to room temperature. 7.11.1.2 Using a large glass stirring rod, mix the authentic sample thoroughl y. 7.11.1.3 Using a large glass stirring rod, mix the clean NAF ( sent from the

supplier) thoroughly . 7.11.2 Extraction.

7.11.2.1 Using an automatic positive displacement pipetter and a disposable pipette

tip transfer 0.1 - mLof the authentic sample into a 25 - mLvial. 7.11.2.2 Using an automatic pipetter and a disposable pipette tip dispense a 10 - mL

aliquot of solvent grade isopropyl alcohol (IPA) into the 25 mLvial. 7.11.2.3 Cap the vial and vortex the vial for ca. 10

– 15 seconds. 7.11.2.4 Let the sample extract stand for approximately 5 minutes, allowing the solids to separate. 7.11.2.5 Using a 5 - mLdisposable plastic sy ringe remove 4 mLof the extract from the 25 - mLvial. 7.11.2.6 Filter 4 mL of extract through a Teflon s yringe filter (25 - mm diameter,

0.45 μm pore size), collecting the filtrate in a labeled 4 - mLvial. 7.11.2.7 Dispose of the PFTE s yri nge filter. 7.11.2.8 Using a black permanent mar ker, label a Sep Pak ® C 18 cartridge with the sample identification.7 - 8 7.11.2.9 Place the labeled Sep Pak® C 18 cartridge onto the head of a SPE vacuum

manifold. 7.11.2.10 Using a 5 - mLdisposable plastic sy ringe, draw up exactly

3 - mL(air free) of isopropyl alcohol. 7.11.2.11 Attach the s yringe tip to the top of the C 18 cartridge. 7.11.2.12 Condition the C 18 cartridge with the 3 - mLof isopropyl alcohol by

depressing the plunger slowly . Note: Depress the plunger just to the point when no liquid remains in the sy ringe barrel. Do not force air through the cartridge. Collect the eluate in a waste vial. 7.11.2.13 Remove the sy ringe temporaril y from the top of the cartridge, then remove the plunger, and finally

reattach the s yringe barrel to the top of the C 18 cartridge. 7.11.2.14 Using automatic pipetters and disposable pipe tte tips, transfer 0.5 mL of

the filtered extract into the sy ringe barrel, followed by

a 3.0 - mLtransfer of isopropyl alcohol to the sy ringe barrel. 7.11.2.15 Insert the plunger and slowly depress it to pass only

the extract and solvent through the preconditioned C 1 8 cartridge. Note: Depress the plunger just to the point when no liquid remains in the sy ringe barrel. Do not force air through the cartridge. Collect the eluate in a waste vial. 7.11.2.16 Remove the sy ringe temporaril y from the top of the cartridge, then remove the plunger, and finally

reattach the s yringe barrel to the top of the C 18 cartridge. 7.11.2.17 Using an automatic pipetter and disposable pipette tip, transfer 2.0 mL of

isopropyl alcohol to the sy ringe barrel. 7.11.2.18 Insert the plunger and slowly depress it to pass the solv ent through the C 18 cartridge. Note: Depress the plunger just to the point when no liquid remains in the sy ringe barrel. Do not force air through the cartridge. Collect the eluate in a waste vial. 7.11.2.19 Remove the sy ringe and labeled C 18 cartridge from the top o f the SPE vacuum manifold. 7.11.2.20 Prepare a reagent blank according to the procedures outlined in Section

7.9.5 .7 - 9 7.11.2.21 Prepare the necessary NAF reference blanks for each type of NAF encountered in the field samples accordin g to the procedures outlined in Section 7.9.6 . 7.11.2.22 Prepare the positive control (1% crude oil equivalent) according to Section

7.9.6.2 . 7.11.3 Reagent blank fluorescence testing .

7.11.3.1 Place the reagent blank cartridge in a black box, under a black light. 7.11.3.2 Determine the presence or absence of fluorescence for the reagent blank

cartridge. If fluorescence is detected in the blank, anal ys is of the samples is halted until the source of cont amination 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. 7.11.4 Sample fluorescence te sting.

7.11.4.1 Place the respective NAF reference blank ( Section 7.9.6 ) onto the tray

inside the black box. 7.11.4.2 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. 7.11.4.3 Turn on the black light. 7.11.4.4 Compare the fluorescence of the sample cartridge with that of the negative

control cartridge (NAF blank, Section 7.9.6.1 ) and posi tive control cartridge (1% crude oil equivalent, Section 7.9.6.2 ). 7.11.4.5 If the fluorescence of the sample cartridge is equal to or brighter than the

positive control cartridge (1% crude oil equivalent, Section 7.9.6.2 ), the sample is considered contaminated. Otherwise, the sample is clean. **7.12 Data Analysis and Calculations**  Specific data anal ys is techniques and calculations are not performed in this SOP. **7.13 Method Performance**  Thi s method was validated through a single laboratory study, conducted with rigorous statistical experimental design and interpretation ( Section 7.16 , Reference 4). **7.14 Pollution Prevention**  7.14.1 The solvent used in this method poses little threat to the environment when recycled

and managed properl y.7 - 10

**7.15 Waste Management**  7.15.1 It is the laboratory's responsibility to compl y 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. 7.15.2 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. 7.15.3 For further information on waste management, cons ult “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 Stree t, NW, Washington, DC 20036. **7.16 References**  1. “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. 2. “OSHA Safety and Health Standards, General Industry ,” (29 CFR 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976). 3. “Handbook of Anal yt ical Quality Control in Water and Wastewater Laboratories,” USEPA, EMSL - Ci , Cincinnati, OH 45268, EPA

– 600/4

–79

–019, March 1979. 4. Report of the Laboratory Evaluation of Static Sheen Test Replacements

—Reverse Phase Extraction (RPE) Method for Detecting Oil Contamination in Sy nthetic Based Mud (SBM). October 1998. Available from API , 1220 L Street, NW, Washington, DC 20005

– 4070, 202

– 682

– 8000. 5. U.S. EPA. 2001. Effluent L imitations Guidelines and New Source Performance Standards for the Oil and Gas Extraction Point Source Category . Federal Register, 66: 6849 (22 January

2001). 6. U.S. EPA . 2001. Effluent L imitations Guidelines and New Source Performance Standards for the Oil and Gas Extraction Point Source Category : Correction . Federal Register, 66: 30811 ( 8 June 2001).8 - 1

**8. D**  **ETERMINATION OF THE A**  **MOUNT OF N**  **ON -** **A QUEOUS**  **D RILLING**  **F LUID**  **(NAF) B**  **ASE F**  **LUID FROM D**  **RILL C**  **UTTINGS BY A R** **ETORT C**  **HAMBER (D**  **ERIVED FROM API**  **R ECOMMENDED**  **P RACTICE**  **13B –** **2) (EPA**  **M ETHOD**  **1674) 8.1**  **Description** 8.1.1 This procedure is specifically intended to measure the amount of non - aqueous drilling fluid (NAF) base fluid from cuttings generated d uring 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 properl y operating “Retort” instrument. 8.1.2 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 requ ires special attention to the details of sample handling (e.g., location, method, frequency). See Sections 8.5 and 8.6 for minimum requirements for collecting representative samples. Additional samp ling procedures in a given area may be specified b y the NPDES permit controlling authority . **8.2 Equipment**  8.2.1 Retort instrument

—The recommended retort instrument has a 50 - cm 3 volume with an external heating jacket. 8.2.1.1 Retort Specifications:

a. Retort assembly

— retort body, cup and lid. Material: 303 stainless steel or equivalent. Volume: Retort cup with lid. Cup Volume: 50 - cm 3

. Precision: ±0.25 - cm 3

. b. Condenser

—capable of cooling the oil and water vapors below their liquification temperature. c. Heating jacket

— nominal 350 watts. d. Temperature control

— capable of limiting temperature of retort to at least 930°F (500 °C) and enough to boil off all NAFs. 8.2.2 Liquid receiver (10 - cm 3 , 20 - cm 3 )

—the 10 - cm 3 and 20 - cm 3 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 anal ys t shall use the 10 - cm 3 liquid receiver with 0.1 ml graduations to achieve greater accuracy .8 - 2 8.2.2.1 Receiver specifications:

Total volume: 10 - cm 3 , 20 - cm 3

. Precision (0 to 100%): ±0.05 cm 3 , ±0.05 cm 3

. 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 - cm 3 , 0.10 - cm 3

. Calibration: To contain “TC” @ 20 °C. Scale: cm 3 , cm 3

. 8.2.2.2 Material

—Py

rex ® or equivalent glass. 8.2.3 Toploading balance

— capable of weighing 2 , 000 g and precision of at least 0.1 g.

Unless motion is a problem, the anal ys t shall use an electronic balance. Where motion is a problem, the anal ys t may use a triple be am balance. 8.2.4 Fine steel wool (No. 000)

—for packing retort body . 8.2.5 Thread sealant lubricant: high temperature lubricant, e.g. Never - Seez ® or equivalent. 8.2.6 Pipe cleaners

—to clean condenser and retort stem. 8.2.7 Brush

—to clean receivers. 8.2.8 Retort spatula

—to clean retort cup. 8.2.9 Corkscrew

—to remove spent steel wool. **8.3 Procedure**  8.3.1 Clean and dry the retort assembly

and condenser. 8.3.2 Pack the retort body with steel wool. 8.3.3 Apply

lubricant/sealant to threads of retort cup and retort stem. 8.3.4 Weigh and record the total mass of the retort cup, lid, and retort body with steel wool.

This is mass (A), grams. 8.3.5 Collect a representative cuttings sample ( see Note in Section 8.1 ). 8.3.6 Partially

fill the retort cup with cuttings and place the lid on the cup. 8.3.7 Screw the retort cup (with lid) onto the retort body , weigh and record the total mass.

This is mass (B), grams. 8.3.8 Attach the condenser. Place the retort assembl y into the heating jacket. 8.3.9 Weigh and record the mass of the clean and dry liquid receiver. This is mass (C), grams. Place the receiver below condenser outlet.8 - 3

8.3.10 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. 8.3.11 Remove the liquid receiver. Allow it to cool. Record the volume of water recovered.

This is (V), cm 3

. 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 ret ort assembly from the heating jacket b y grasping the condenser. Carefully heat the receiver along the emulsion band by

gentl y 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. 8.3.12 Weigh and record the mass of the receiver and its liquid contents (oil plus water).

This is mass (D), grams. 8.3.13 Turn off the retort. Remove the retort assembly and condenser from the heating jacket and allow them to cool. Remove the condenser. 8.3.14 Weigh and record the mass of the cooled retort assembly without the condenser. This is mass (E), grams. 8.3.15 Clean the retort assembly and condenser. **8.4 Calculations**  8.4.1 Calculate the mass of oil (NAF base fluid) from the cuttings as follows:

8.4.1.1 Mass of the wet cuttings sample (Mw) equals the mass of the retort

assembly with the wet cuttings sample (B) minus the mass of the empty retort assembl y (A). M w = B

− A [ 8 - 1 ] 8.4.1.2 Mass of the dry retorted cuttings (M D ) equals the mass of the cooled retort assembly (E) minus the mass of the empty retort assembly

(A). M D = E

− A [ 8 - 2 ] 8.4.1.3 Mass of the NAF base fluid (M BF ) 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).

M BF = D

− (C + V) [ 8 - 3 ] Note: Assuming the density of water is 1 g/cm 3 , the volume of water is equivalent to the mass of the water.8 - 4

8.4.2 Mass balance requirement:

The sum of M D , M BF , and V shall be within 5% of the mass of the wet sample. [ 8 - 4 ] The procedure shall be repeated if this requirement is not met. 8.4.3 Reporting oil from cuttings:

8.4.3.1 Assume that all oil recovered is NAF base fluid. 8.4.3.2 The mass percent NAF base fluid retained on the cuttings (%BF i ) for th e

sampled discharge “i” is equal to 100 times the mass of the NAF base fluid (M BF ) divided b y the mass of the wet cuttings sample (Mw). [ 8 - 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 (%BF SVD ) for each small volume NAF - cuttings discharges; or (b) use a default value of 25% NAF base fluid retained on the cuttings. 8.4.3.3 The mass percent NAF base fluid retained on the cuttings is determin ed

for all cuttings wastestreams and includes fines discharges and any accumulated solids discharged. (S ee Section 8.4.3.6 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 .) 8.4.3.4 A mass NAF - cuttings discharge fraction (X, unitless) is calculated for all

NAF - cuttings, fines, or accumulated solids discharges every time a set of reto rts is performed (Section 8 .4.3.6 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 8.5 and 8.6 ). The mass NAF - cuttings discharge fraction (X) for each discharge is calculated b y direct measurement as:

%BF i = M BF × 100

M w M D + M BF + V = 0.95 to 1.05 M w8 - 5 [ 8 - 6 ] Where: X i = Mass NAF - cuttings discharge fraction for NAF - cuttings, fines, or

accumulated solids discharge “i”, (unitless) F i = Mass of NAF - cuttings discharged from NAF - cuttings, fines, or

accumulated solids discharge “i” ov er a specified period of time ( see Sections 8.5 and 8.6 ), (kg) G = Mass of all NAF - cuttings discharges into the ocean during the

same period of time as used to calculate F i , (kg) If an operator has more than one point of NAF - cuttings discharge, the mass faction (X i ) must be determin ed b y: (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 onl y discharging from the cuttings dryer and the fines removal unit; or (c) using direct measurement of “F i ” ( see Equation 8 - 6) for fines and accumulated solids, using Equation 8 - 6A to calculate “G EST ” for use as “G” in Equation 8 - 6, and calculating the mass (kg) of NAF - cuttings discharged from the cuttings dryer (F i ) as the difference between the mass of “G EST ” calculated in Equation 8 - 6A (kg) and the sum of all fines and accumulated solid s mass directly

measured (kg) ( see Equation 8 - 6). G EST = Estimated mass of all NAF - cuttings discharges into the ocean during the same period o f time as used to calculate F i

( see Equation 8 - 6), (kg) [ 8 - 6A] Where : G EST = Hole Volume (bbl) × (396.9 kg/bbl) × (1 + Z/100) Z = The base fluid retained on cuttings limitation or standard (%)

which appl y to the NAF being discharge ( see 40 CFR§§435.13. and 4 35.15). Hole Volume (bbl) = [Cross - Section Area of NAF interval (in2 )] × Average

Rate of Penetration (feet/hr) × period of time (min) used to calculate F i ( see Equation 8 - 6) × (1 hr/60 min) × (1 bbl/5.61 ft 3 ) × (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 F i ( 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 F i ( see Equation 8 - 6)

X i = F i G8 - 6 Note: Operators with one NAF - cuttings discharge may set the mass NAF cuttings discharge fraction (X i ) equal to 1.0. 8.4.3.5 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 (%BF T) is calculated every time a set of retorts is performed. The single total mass percent NAF base fluid retained on cuttings value (%BF T) is calculated as:

%BF T,j = Σ(X i ) × (%BF i ) [ 8 - 7 ] Where: %BF T,j = Total mass percent NAF base fluid retained on cuttings value for

retort set “j” (unitless as percentage, %) X i = Mass NAF - cuttings discharge fraction for NAF - cutting s, fines, or

accumulated solids discharge “i”, (unitless) %BF i = Mass percent NAF base fluid retained on the cuttings for NAF cuttings, fines, or accumulated solids discharge “i” , (unitless as percentage, %) Note: ΣX i = 1. Operators with one NAF - cuttings discharge may set %BF T,j equal to %BF i . 8.4.3.6 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 perform ing 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 , operato rs 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: a. Use side scan sonar or shallow seismic to determine the presence of high density chemos ynthetic communities. Chemosy nthetic communities are assemblages of tube worms, clams, mussels, and bacterial mats that occur at natural hydrocarbon seeps or vents, generall y in water depths of 500 meters or deeper. Seafloor discharges8 - 7 of large cuttings for the proper operation of subsea pumps shall not be permitted within 1 , 000 feet of a high density chemosynthetic community . b. Seafloor discharges of large cuttings for the proper operation of subsea pumps shall be visually

monitored and documente d by a Remotel y 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 di scharge hose position. Near - seabed currents shall be obtained at the time of the visual monitoring. c. Seafloor discharges of large cuttings for the proper operation of subsea pumps shall be directed within a 150 foot radius of the wellbore. 8.4.3.7 The weighted mass ratio averaged over all NAF well sections (%BF well) 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 (%BF well) is calculated as the arithmetic average of all total mass percent NAF base fluid retained on cuttings values (%BF T) and is given by the following expression: 

##   n BF % BF % n 1

j j

T, well 

## 

  [ 8 - 8 ] Where: %BF well = Weighted mass ratio averaged over all NAF well sections (unitless

as percentage, %) %BF T,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 dis charge sampling interval (i.e. , displaced interfaces, accumulated solids in sand traps, pit clean - out sol ids, 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 calcul ation of the weighted mass ratio averaged over all NAF well sections (%BF well). The mass fraction of the small volume NAF - cuttings discharges (X SVD ) will be determined by dividing the mass8 - 8 of the small volume NAF - cuttings discharges (F SVD ) by the total mas s of NAF - cuttings discharges for the well drilling operation (G well + F SVD ). [ 8 - 9 ] Where: X SVD = M ass fraction of the small volume NAF - cuttings discharges

(unitless) F SVD = M a ss of the small volume NAF - cuttings discharges (kg) Gwell = M ass of total NAF - cuttings from the well (kg)

The mass of small volume NAF - cuttings discharges (F SVD ) shall be determined b y multiplying the density of the small volume NAF - cuttings discharges ( ρ svd) times the volume of the small volume NAF - cuttings discharges (V SVD ).

F SVD = ρ svd × V SVD [ 8 - 10 ] Where: F SVD = M ass of small volume NAF - cuttings discharges (kg) ρ svd = D ensity of the small volume NAF - cuttings discharges (kg/bbl) V SVD = V olume 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 (V SVD ) 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 (G well ) shall be either: (a) Measured; or (b) calculated b y 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 (V well ) for all NAF well sections times a default value for the density the formation of 2.5 g/cm 3 (396.9 kg/bbl).



##     bbl kg 9 . 396 bbl V n %BF 1 G well

n 1 j j

T, well                 

               

# 

 [ 8 - 11 ]

Where: Gwell = T otal mass of NAF - cuttings discharges for the well (kg) 

##   n %BF n 1 j j

T, 

## 

 = see Equation 8 - 8 (unitless as a percentage) Vwell = T otal hole volume (V well) for all NAF well sections (bbl) X SVD = F SVD

Gwell+ F SVD8 - 9 Th e total hole volume of NAF well sections (Vwell) will be calculated as: [ 8 - 12 ] For wells where small volume discharges associated with cuttings are made, %BF well becomes: 

###   

##   SVD SVD n 1 j j

T, SVD well BF % X n %BF X 1 %BF                                  

# 

 [ 8 - 13 ] Note: See Sections 8.5 and 8.6 to determine the sampling frequency to determine the total number of retort sets required for all NAF well sections. 8.4.3.8 The total number of retort sets (n) is increased b y 1 for each sampling

interval ( see Section 8.5.2.4 ) when all NAF cuttings, fines, or accumulated solids for that sampling interval are retained for n o 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 al l NAF cuttings, fines, or accumulated solids are retained for no discharge. 8.4.3.9 Operators that elect to use the Best Management Practices (BMPs) for

NAF - cuttings shall use the procedures outlined in Section 8.6 . **8.5 Requirements for**  **Sa mpling Cuttings Discharge Streams for**  **use with this Method** 8.5.1 Sampling L ocations

8.5.1.1 Each NAF - cuttings waste stream that discharges into the ocean shall be

sampled and anal yz ed as detailed earlier in Section **Error! Reference source not found.**  **Error! Reference source not found.**  . 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 oc ean. 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 anal ys is. 8.5.1.2 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 Vwell (barrels) = 

# Σ Bit diameter (in) 2 × change in measured depth (ft) 1,0298 - 10 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. 8.5.1.3 Operators shall provide a simple schematic diagram of the solids control

sy stem and sample locations to the NPDES permit controlling authority. 8.5.2 Ty

pe of Sample and Sampling Frequency 8.5.2.1 Each NAF - cuttings, fines, or a ccumulated 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 8.5.2.4 ). Operators shall collect a single discrete NAF cuttings sample for each NAF - cuttings waste stream discharged to the ocean during every

sampling interval. 8.5.2.2 Operators shall use measured depth in feet from the Kell y bushing when

samples are collected. 8.5.2.3 The NAF - cuttings s amples collected for the mass fraction anal ys is ( see

Equation 8 - 6 ) shall also be used for the retort analy sis ( see Equations 8 - 1 through 8 - 5 ). 8.5.2.4 Operators shall collect and anal yz e 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 anal yz e 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 c ount 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 . 8.5.2.5 The operator shall measure the individual masses (F i , 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 8.5.2.4 ). The operator shall ensure that all NAF - cuttings are capture for mass analy sis during the same sampling time period (e.g., <10 minutes) at approximately the same time ( i.e., all individual mass samples collected withi n one hour of each other).8 - 11 8.5.2.6 Operators using Best Management Practices (BMPs) to control NAF cuttings discharges shall follow the procedures in Section 8.6 . 8.5.3 Sample Size and Handling

8.5.3.1 The volume of each sample depends on the volume tric flow rate (cm 3 /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 differ ent 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 m inutes) to collect NAF - cuttings samples from each NAF - cuttings waste stream. Each NAF cuttings sample size shall be at least one gallon. Operators shall clearl y mark each container to identify each NAF - cuttings sample. 8.5.3.2 Operators shall not decant, heat, was h, or towel the NAF - cuttings to

remove NAF base fluid before mass and retort analy sis. 8.5.3.3 Operators shall first calculate the mass of each NAF - cuttings sample and

perform the mass ratio analy sis ( see Equation 8 - 6 ). Operators with only one NAF - cuttings discharge may skip this step ( see Section 8.4.3.4 ). 8.5.3.4 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. 8.5.3.5 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 . 8.5.3.6 Operators shall not discharge any s ample before successfull y completing

the mass and retort anal yses [i.e. , mass balance requirements ( see Section 8.4.2 ) are satisfied]. Operators shall immediately re - run the retort analy ses if the mass balance requirements ( see Equation 8 - 4 ) are not within a tolerance of 5% ( see Section 8.4.2 , Equation 8 - 4 ). 8.5.4 Calculations

8.5.4.1 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 8.5.1.1 ) for each sampling interval ( s ee Section 8.5.2.4 ) using the procedures outlined earlier in Section **Error! Reference source not found. Error! Reference source**  **not found.** .8 - 12 8.5.4.2 Operators shall tabulate the following data for each individual NAF cuttings s ample: (1) Date and time of NAF - cuttings sample collection; (2) time period of NAF - cuttings sample collection ( see Section 8.5.3.1 ); (3) mass and volume of each NAF - cuttings sample; (4) measured depth (feet) at NAF - cuttings sample collection ( see Section 8.5.2.2 ); (5) respective linear feet of hole drilled represented b y the NAF - cuttings sample (feet); and (6) the drill bit diameter (inches) used to generate the NAF - cuttings sample cuttings. 8.5.4.3 Operators shall calculate a single total mass percent NAF base fluid

retained on cuttings value (%BFT) for each sampling interval ( see Section 8.5.2.4 ) using the procedures outlined in Se ction 8.4 . 8.5.4.4 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 cuttin gs sample collection and retort anal ys es; (2) measured depth of well (feet) at start of NAF - cuttings sample collection ( see Section 8.5.2.2 ); (3) respective linear feet of hole drilled represented b y 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. 8.5.4.5 Operators shall calculate the weighted mass ratio averaged over all NAF

well se ctions (%BF well) using the procedures outlined in Section 8.4 . 8.5.4.6 Operators shall tabulate the following data for each weighted mass ratio

averaged over all NAF well sections (%BF well) 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 Section s 8.5.2.4 and 8.5.2.6 ); (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 8.6 ). **8.6 Best**  **Management Practices (BMPs) for use with this Method**  8.6.1 Overview of BMPs

8.6.1.1 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 fa cility BMP Plan, operators shall develop a BMP in accordance with the requirements in this addendum.8 - 13 8.6.1.2 The BMP requirements contained in this section were compiled from

several Regional permits, an EPA guidance document (i.e. , Guidance Document for Developin g 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 operatio ns. 8.6.1.3 Operators are not required to use BMPs if all NAF - cuttings discharges are

monitored in accordance with Sections 8.1 through 8.4 . 8.6.2 BMP Plan Purpose and Objectives

8.6.2.1 Operators shall design the BMP Pl an 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 b y conducting the following evaluations. 8.6.2.2 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. 8.6.2.3 Each facility

component or sy stem 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). 8.6.2.4 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 re aching 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. 8.6.3 BMP Plan Requirements

8.6.3.1 The BMP Plan may reflect requirements within the po llution prevention requirements required b y 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. 8.6.3.2 The operator shall certify that its BMP Plan is c omplete, 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 th e BMP Plan. For new or modified NPDES permits, the certification shall be made no later than the effective date of the new or8 - 14 modified permit. For existing NPDES permits, the certification shall be made within one year of permit issuance. 8.6.3.3 The BMP Plan shal l:

a. 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, a nd 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). b. In clude the following provisions concerning BMP Plan review.

• Be revi ewed by

permittee's drilling engineer and offshore installation manager (OIM) to ensure compliance with the BMP Plan purpose and objectives set forth in Section 8.6.2 .

• In clude a statement that the review has been completed and that the BMP Plan fulfills the BMP Plan purpose and objectives set forth in Section 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. 8.6.3.4 Address each component or sy stem capable of generating or causing a

release of significant amounts of NAF and identify specific preventative or remedial m easures to be implemented. 8.6.4 BMP Plan Documentation

8.6.4.1 The operator shall maintain a cop y 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. 8.6.5 BMP Plan Modification

8.6.5.1 For those NAF wastestreams controlled through BMPs, the operator shall

amend the BMP Plan when ever there is a change in the facility or in the operation of the facility

which materiall y increases the generation of those NAF - wastes or their release or potential release to the receiving waters. 8.6.5.2 At a minimum the BMP Plan shall be reviewed once every f ive ye ars and amended within three months if warranted. Any such changes to the BMP Plan shall be consistent with the objectives and specific requirements8 - 15 listed in this addendum. All changes in the BMP Plan shall be reviewed by the permittee's drilling en gineer and offshore installation manager. 8.6.5.3 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. 8.6.6 Specific Pollution Prevention Requirements for NAF Discharges Associated with

Cuttings 8.6.6.1 The following sp ecific pollution prevention activities are required in a

BMP Plan when operators elect to control NAF discharges associated with cuttings b y a set of BMPs. 8.6.6.2 Establishing programs for identifying, documenting, and repairing

malfunctioning NAF equipment, trac king NAF equipment repairs, and training personnel to report and evaluate malfunctioning NAF equipment. 8.6.6.3 Establishing operating and maintenance procedures for each component in

the solids control sy stem in a manner consistent with the manufacturer's design criteria. 8.6.6.4 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. 8.6.6.5 A daily

retort analy sis shall be performed (in accordance with Sections 8.1 through 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 anal ys es shall be documented in the well retort log. The operators shall use the calculation procedures detailed in Section 8 .4 ( see Equations 8 - 1 through 8 - 8 ) to determine the arithmetic average (%BF well) of the retort anal ys es taken during the first 0.33 X feet drilled with NAF. a. When the arithmetic average (%BFwell) of the retort anal ys es 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. b. When the arithmetic average (% BF well) of the retort analy ses 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)8 - 16 0.33 X fe et drilled with NAF where X is the anticipated total feet to be drilled with NAF for that particular well. The retort anal ys es for the first and second 0.33 X feet shall be documented in the well retort log.

• When the arithmetic average (%BF well) of the ret ort analy ses taken during the first 0.66 X feet (i.e. , retort anal ys es 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 mo nitoring 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 (%BF well) of the retort analy ses taken during the first 0.66 X feet (i.e. , retort anal ys es 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 continu e for all remaining NAF sections for that particular well. The retort analy ses for all NAF sections shall be documented in the well retort log. c. When the arithmetic average (%BFwell) of the retort anal ys es 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. d. The operator shall include re tort monitoring data and dates of retort monitored and non - retort - monitored NAF - cuttings discharges managed b y BMPs in their NPDES permit reports. 8.6.6.6 Establishing mud pit and equipment cleaning methods in such a way as to minimize the potential for building - u p drill cuttings (including accumulated solids) in the active mud s ys tem and solids control equipment sy stem. These cleaning methods shall include but are not limited to the following procedures. a. Ensuring proper operation and efficiency of mud pit agitatio n equipment. b. Using mud gun lines during mixing operations to provide agitation in dead spaces.8 - 17 c. Pumping drilling fluids off of drill cuttings (including accumulated solids) for use, recycle, or disposal before using wash water to dislodge solids.9 - 1

**9. PAH**  **C ON**  **TENT OF O**  **IL BY HPLC/UV**  **(EPA M**  **ETHOD 1654,**  **R EVISION**  **A) 9.1**  **Scope and Application** 9.1.1 This method is designed to determine the pol ynuclear 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. 9.1.2 This method is for use in the Environmental Protection Agency ’s (EPA’s) survey and monitoring programs under the Federal Water Pollution Control Act. 9.1.3 For oil in drilling muds, this method is designed to be used in conjunction with the

extraction procedure in EPA Method 1662. 9.1.4 The level of PAH in Table 9 - 1 ty pifies the minimum level that can be detected in oil with this method. 9.1.5 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. 9.1.6 This method is restricted to use by or under the supervision of anal ys ts experienced in the use of HPL C sy stems and in the interpretation of liquid chromatograms. Each anal ys t must demonstrate the ability to generate acceptable results with this method using the procedure described in Section 9.8.2 . **9.2 Summary of Meth**  **od** 9.2.1 An oil sample is diluted in acetonitrile and a 20 - μLaliquot is injected into the HPL C.

The PAHs are partiall y s eparated b y HP LC and detected with the UV detector. 9.2.2 Id entification of PAH (qualitative anal ys is) is performed b y comparing the response

of th e 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. 9.2.3 Quantitative anal ys is is performed b y calibrating the HPL C with phenanthrene usin g

an external standard technique, and using the calibration factor to determine the concentration of PAH in the sample. 9.2.4 Quality

is assured through reproducible calibration and testing of the extraction and HPL C systems. **9.3 Interferences**  9.3.1 Solvents, reagents, gl assware, and other sample processing hardware may lead to discrete artifacts and/or elevated baselines causing misinterpretation of chromatograms.9 - 2 9.3.1.1 All materials used in the anal ys is shall be demonstrated to be free from

interferences b y 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 s ys tems may be required. 9.3.1.2 Glassware and, where possible, reagents are cleaned by solvent rinse and/or baking at 450 ° C for a minimum of 1 hour. 9.3.2 When used in conjunction with Method 1662, blanks extracted in that method are

treated as an integral part of this method. 9.3.3 Interferences co - extracted fro m samples may vary from source to source, depending on the diversity

of the site being sampled. **9.4 Safety**  9.4.1 The toxicity

or carcinogenicity

of each compound or reagent used in this method has not been precisel y defined; however, each chemical should be treated as a potential health hazard. Exposure to these chemicals must be reduced to the lowest possible level. 9.4.2 The laboratory is responsible for maintaining a current awareness file of OSHA regulations regarding the safe handling of the chemicals specified in thi s method. A reference file of material safety data sheets (MSDSs) should also be made available to all personnel involved in the chemical anal ys is. Additional information on laboratory safety can be found in References 1 through 3. 9.4.3 Methylene chloride has b een 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. **9.5 Apparatus and Materials**  NOTE : Brand names, suppliers, and part numbers are for illustrative purpose s 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 . 9.5.1 Equipment for glassware cleaning.

9.5.1.1 Laboratory

sink with overhead fume hood. 9.5.1.2 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, B31 H or X31TS, or equivalent). 9.5.2 Equipment for sample preparation.

9.5.2.1 Laboratory

fume hood.9 - 3 9.5.2.2 Analy

tical balance: Capable of weighing 0.1 mg. 9.5.2.3 Glassware.

a. Disposable pipettes: Pasteur, 150 mm long b y 5 mm i.d. (Fisher Scientific 13 - 678 - 6A, or equivalent). b. Glass pipett es: 1.0 - and 10 - mL , accurate to 1 % or better. c. Volumetric flasks: Glass, 10 - and 100 - mL . 9.5.2.4 Sample vials: Amber glass, 2 - to 5 - mLwith PTFE - lined screw - cap, to fit

HPL C autosampler. 9.5.3 High - performance liquid chromatograph (HPL C): An anal yt ical s ys tem complete

w ith pumps, sample injector, column oven, and ultra - violet (UV) detector. 9.5.3.1 Pumping sy stem: Capable of isocratic operation and producing a linear

gradient from 50% water/50% acetonitrile to 100% acetonitrile in 10 minutes (Waters 600E, or equivalent). 9.5.3.2 Sample injector: Capable of automated injection of up to 30 samples

(Waters 700, or equivalent). 9.5.3.3 Column oven: Capable of operation at room ambient to 50 ° C (Waters

TCM, or equivalent). 9.5.3.4 Column: Two C 18 columns, 150 mm long by 4.6 mm i.d., 300 angstroms

(V ydac 201 T P5415, or equivalent) connected in series, preceded by one C 18 guard column, 30 mm long b y 4.6 mm i.d., 300 angstroms (Vydac 201 GCC54T, or equivalent), operated at the conditions shown in Table 9 - 1 . 9.5.3.5 Detector: UV operated at 254 nm (Waters 490E, or equivalent). 9.5.4 Data s ys tem.

9.5.4.1 Data acquisition: The data sy stem shall collect and record LC peak areas

and retention times on magnetic media. 9.5.4.2 Calibration: The data s ys tem 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 . 9.5.4.3 Data processing: The data sy stem shall be used to search, locate, identify ,

and quantify

the compounds of interest in each analy sis. Display s of chromatograms are required to verify results. 9.5.4.4 Statistics on initial (Section 9.8.2 ) and ongoing (Section 9.12.6 )

performance sh all be computed and maintained.9 - 4

**9.6 Reagents**  9.6.1 Solvents.

9.6.1.1 Sample preparation: Methylene chloride, distilled in glass (Burdick and

Jackson, or equivalent). 9.6.1.2 HPL C: Methanol, acetonitrile, and water, HPL C quality . 9.6.2 Standards: Purchased as solutions or mixtures with certification to their purity ,

concentration, and authenticity , or prepared from materials of known purity and composition. I f 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. 9.6.2.1 Stock solutions: Prepare in methylene chloride or methanol and dilute In

acetonitrile for injection into the HPL C. Observe the safety precautions in Section 9.4 . a. Diesel oil solutions

• Stock solution in methylene chloride (62.5 m g/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 - mLground 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 completel y dissolved, remove 1.00 mLand place in a 50 - mLvolumetric flask. Dilute to the mark with acetonitrile. Mix thoroughl y and transfer to a clean 150mL bottle with PTFE - line d cap. b. Poly nuclear aromatic hydrocarbons - naphthalene, phenanthrene, and indeno[1,2,3 - cd

]py rene: Dissolve an appropriate amount of reference material in a suitable solvent. For example, weigh 10.0 mg of naphthalene in a 10 - mLvolumetric flask and fill to th e mark with methanol. After the naphthalene is completel y dissolved, transfer the solution to a 15 - mLvial with PTFE - lined cap. c. Stock solutions should be checked for signs of degradation prior to the preparation of calibration or performance test standards . 9.6.2.2 PAH calibration standards (CAL): Dilute and mix the stock solutions

(Section 9.6.2.1b ) in acetonitrile to produce the calibration standards shown in Table 9 - 2 . The three solutions permit the response of phenanthrene to be measured as a function of concentration, and9 - 5 naphthalene and indeno[1,2,3 - cd ]py rene permit the retention time window for PAH to be defined. The medium - level solution is used for calibration verification (Section 9.12.2 ). 9.6.2.3 Precisio n and recovery standard: The diesel oil calibration solution (Section 9.6.2.1a) , second bullet) is used for initial precision and recovery (IPR; Section 9.8.2 ) and ongoing precision and recovery (OPR, Section 9.12.6 ). 9.6.2.4 Stability

of solutions. a. When not being used, standards are stored in the dark at - 20 to - 10 ° C in screw - capped vials with PTFE - lined li ds. 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. b. Stand ard soluti ons used for quantitative purposes (Sections 9.6.2.1 through 9.6.2.3 ) shall be anal yz ed within 48 hours of preparation and on a monthly

basis thereafter for signs of degradation. Standards will remain acceptable if the peak area remains within ±15% of the area obtained in the initial analy sis of the standard. **9.7 Calibration**  9.7.1 Assemble the HPL C and establish the operating conditions in Table 9 - 2 . 9.7.2 Retention time adjustment.

9.7.2.1 Inject 20 μL - of the medium level calibration standard ( Table 9 - 2 ). 9.7.2.2 Locate the three peaks in this standard. 9.7.2.3 Adjust the initial solvent mixture, the isocratic hold, the gradient, and the

final is ocratic hold until the retention times are within + 1 minute of the retention times given in Table 9 - 2 . 9.7.3 Minimum level: Analy ze 20 μLof the low - level calibration standard ( Table 9 - 2 ) and verify that the H PL C instrument meets the minimum level for phenanthrene in Table 9 - 1 . 9.7.4 External standard calibration.

9.7.4.1 Analyze 20 μL of each calibration standard ( Table 9 - 2 ) beginning with the

lowest concentration and proc eeding to the highest using to the procedure in Section 9.11 . 9.7.4.2 Record the areas for the phenanthrene peak and the height of the

phenanthrene peak in the high - level standard.9 - 6 9.7.4.3 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. 9.7.4.4 Linearity: I f 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 sy stem shall be recalibrated. 9.7.5 The average calibration factor is verified on each working 8 - hour shift b y the

measurement of the medium - level calibration standard (Section 9.12.5 ). 9.7.6 Single - point calibration for diesel oil: Inject the precision and recovery standard (Section 9.6.2.3 ) to produce a si ngle calibration point for diesel oil. 9.7.6.1 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 ]py rene peak or until the detector signal returns to a stable baseline, whichever comes later, as shown in Figure 9 - 1 . 9.7.6.2 Determine the calibration factor for diesel oil b y dividing the integrated

area ( 9.7.6.1 ) b y the diesel oil concentration ( Section 9.6.2.1a) , second bullet). **9.8 Quality Assurance/Quality Control**  9.8.1 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 ini tial demonstration of laboratory capability, an ongoing anal ys is of standards and blanks as a test of continued performance, analy ses of spiked samples to assess accuracy , and anal ys is of duplicates to assess precision. L aboratory performance is compared t o established performance criteria to determine if the results of anal ys es 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 rec overy

(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 Table 9 - 1 for extracts from Method 1 662 shall be met. 9.8.1.1 The anal ys t 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 9.8.2 . 9.8.1.2 The anal ys t is permitte d 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 anal ys t is required to achieve the minimum level (Section 9.7.3 ) and to repeat the procedure in Section 9.8.2 to demonstrate method performance.9 - 7 9.8.1.3 Analy ses of spiked samples are required to demonstrate method accuracy

when extracts from Method 1662 are anal yz ed. The procedure and QC criteria for spiking are described in Section 9.8.3 . 9.8.1.4 Analy ses 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 9.8.4 . 9.8.1.5 Analy ses of blanks are required to demonstrate freedom from

contamination. The procedures and criteria for analy sis of a blank are described in Section 9.8.5 . 9.8.1.6 The laboratory shall, on an ongoing basis, demonstrate through calibration

verification an d anal ys is of the precision and recovery standard that the anal ys is sy stem is in control. These procedures are described in Sections 9.12.5 and 9.12.6 . 9.8.1.7 The laboratory shall maintain records to define the quality of data that is generated. Development of accuracy statements is described in Sections 9.8.3.2 and 9.12.6.4 . 9.8.2 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 anal yz ed, 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. 9.8.2.1 Using diesel oil, prepare four separate aliquots of the precision and

recovery standard (Sec tion 9.6.2.3 ). If extracts from Method 1662 are anal yz ed, the extracts from the initial precision and recovery test in that method shall be used. Analyze these aliquots using the procedure in Section 9.11 . 9.8.2.2 Using results of the set of four analy ses, compute the average recovery (X) of PAH in mg/mL and the standard deviation of the recovery (s) in mg/mL for ea ch aliquot b y the external standard method (Sections 9.7.4 and 9.14.4 ) . 9.8.2.3 Compare s and X with the corresponding limits for initial precision and

recovery in Table 9 - 1 . If s and X meet the acceptance criteria, s ys tem performance is acceptable and analy sis of oil samples may begin. If, however, s exceeds the precision limit or X falls outside the range for accuracy , s ys tem performance is unacceptable. In this event, review this method, correct the problem, and repeat the test. 9.8.3 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 8.39 - 8 of Method 1662, and th e specification for accuracy is given in Table 9 - 1 of this method. 9.8.3.1 Compare the percent recovery of PAH with the corresponding QC acceptance criteria in 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 9.12.6.3 ) is within the acceptance criteria in Table 9 - 1 , an interference may be present. In thi s 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 anal ytical s ys tem is judged to be out of control and the pro blem shall be identified and corrected, and the sample batch reanal yz ed. 9.8.3.2 As part of the QA program for the laboratory , method accuracy for samples shall be assessed and records shall be maintained. After the anal ys is of five spiked samples in which the rec overy passes the test in Section 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

– 2 Sp to P + 2 Sp . F or example, if P = 90% and S p = 10% for five anal ys es 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). 9.8.4 Duplicates: If extract s from Method 1662 are to be anal yz ed, 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 Table 9 - 1 of this method. If extracts from Method 1662 are not to be anal yz ed, duplicates of the precision and recovery standard (Section 9.6.2.3 ) are anal yz ed, and the specification for RPD is given for PAH in di esel oil in Table 9 - 1 of this method. 9.8.4.1 Analyze each of the duplicates per the procedure in Section 9.11 and

compute the results per Section 9.14 . 9.8.4.2 Calculate the relative perc ent difference (RPD) between the two results

per the following equation: [ 9 - 1 ] Where: D 1 = Concentration of diesel oil in the sample D 2 = Concentration of diesel oil in the sec ond (duplicate) sample 9.8.4.3 The relative percent difference for duplicates shall meet the acceptance

criteria in Table 9 - 1 . If the criteria are not met, the anal ytical sy stem is be judged to be out of control, and the problem must be immediately identified and corrected and the sample set re - extracted and reanal yz ed.

RPD = │D 1 – D 2 │ × 100 [(D 1 + D 2 ) /2]9 - 9

9.8.5 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. 9.8.5.1 Rinse the glas sware used in preparation of the extracts in this method with

acetonitrile and anal yz e a 20 - μLaliquot of the rinsate using the procedure in Section 9.1 1 and compute the results per Section 9.14 . 9.8.5.2 If PAH is detected in a blank at greater than the method detection limit

(MDL) in Table 9 - 1 , analy sis of samples is halted until the source of contamination is eliminated and a blank shows no evidence of contamination. 9.8.6 The specifications contained in this method can be met if the apparatus used is

calibrated properl y, then maintained in a calibrated state. The standards used for initial precision and recovery (IPR, Section 9.8.2 ) and ongoing precision and recovery (OPR, Section 9.12.6 ) should be identical, so that the most precise results will be obtained. The HPL C instrument will provide the most reproducible results if dedicated to the settings and conditions required for the anal ys es given in this method. 9.8.7 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 samp le transportation techniques. **9.9 Sample Collection, Preservation, and Handling**  9.9.1 Oil samples are collected in 20 - to 40 - mLvials with PTFE - or aluminum - foil - lined

caps and stored in the dark at - 20 to - 10 ° C. 9.9.2 If extracts from Method 1662 are to be anal yz ed, 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 analy tes determined in this method, samples shall be extracted within 7 day s of collection and extracts shall be anal yz ed within 40 day s of extraction. 9.9.3 As a precaution against analy te and solvent loss or degradation, sample extracts are stored in glass bottles with PTFE - lined caps, in the dark, at - 20 to - 10 ° C. **9.10 Dilution of Oil and Extracts**  9.10.1 Neat oil samples: If oil is received in neat form, it should be diluted to bring the

concentration within the range of the instrument. If the oil is No. 2 diesel oil, the appropriate concentration will be approximately 2, 000 μg/mL . Mineral oils and other oils containing a lesser PAH content will require less dilution. 9.10.2 Extracts from Method 1662: I f extracts of samples from Method 1662 are to be

anal yz ed, these extracts (from Section 10.4.2 of that me thod) are anal yz ed undiluted unless diesel oil is known or suspected to be present. Extracts of QC samples (IPR,9 - 10 OPR, matrix spikes, and duplicates) from Method 1662 are diluted b y a factor of 10 to bring them within the range of the HPL C. 9.10.3 Dilution of neat oil expected to be dies el oil.

9.10.3.1 Weigh 100 mg into a 10 - mLvolumetric flask and dilute to the mark with

methylene chloride to produce a concentration of 10 mg/mL . Stopper and mix thoroughly . 9.10.3.2 Using a calibrated 1.0 - mLvolumetric pipette, withdraw 1.0 mL of the

solution and place in a 10 - mLvolumetric flask. Then withdraw an additional 0.25 mLof the solution and place in the 10 - mLvolumetric 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). **9.11 High**  **-**

**Performance Liquid Chromatography** 9.11.1 Table 9 - 2 summarizes the recommended ope rating conditions for the HPLC. Included

in this table and in 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 HP LC column system is shown in Figure 9 - 1 . Other HPLC columns, chromatographic conditions, or detectors may be used if the requirements for the minimum level (Section 9.7.3 ) and initial precision and rec overy (Section 9.8.2 ) are met. 9.11.2 Calibrate the s ys tem as described in Section 9.7 or verify calibration as described in Section 9.12 . 9.11.3 Analy sis of extracts.

9.11.3.1 Inject 20 μLof the sample extract, Method 1662 extract, or diluted QC

extract into the HPL C using a high - pressure s yringe or a constant - volume sample - injection loop. Record the volume injected to the nearest 0.1 μL. 9.11.3.2 Upon injection, begin the solvent program used in calibrating the column

(Section 9.7.2.3 ). Record the signal from the time of injection until the detector returns to a stable baseline. Return the solvent to the initial conditions. 9.11.3.3 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 ]py rene peak or until the detector signal returns to a stable baseline, whichever comes later.9 - 11

9.11.4 If the height of the response during the period recorded (Section 9.11.3.2 ) exceeds the

height of the response for phenanthrene during calibration (Section 9.7.4.2 ), dilute the extrac t by successive factors of 10 with acetonitrile and reanal yz e until the response is within the calibration range. **9.12 HPLC System and Laboratory Performance**  9.12.1 At the beginning of each 8 - hour shift during which anal ys es are performed, HPL C

calibration and s ys tem performance are verified. For these tests, anal ys is of the medium level calibration standard ( Table 9 - 2 ) and of the diluted extract of the precision and recovery

standard (Section 9.6.2.3 ) shall be use d to verify all performance criteria. Adjustment and/or recalibration (per Section 9.7 ) shall be performed until all performance criteria are met. Only after all performance criteria are met may

samples and blanks be anal yz ed. 9.12.2 Inject 20 μLof the medium - level calibration standard ( Table 9 - 2 ) into the HPL C

instrument according to the procedure in Section 9.11 . 9.12.3 Retention time: The absolute retention times of the naphthalene, p henanthrene, and

indeno[1,2,3 - cd

]py rene peaks shall be within ±30 seconds of the respective retention times in the initial calibration (Section 9.7.2.3 ). 9.12.4 HPL C resolution: Resolution is acceptable if the peak width at half - height of the phenanthrene peak is less than 30 seconds. 9.12.5 Calibration verification: Compute the concentration of phenanthrene based on the

average calibration factor (Section 9.7.4.4 ). The concentration shall be within the limits in Table 9 - 1 . I f calibration is verified, s ys tem performance is acceptable and anal ys is of blanks and QC samples may begin. If, however, the concentration falls outside of the calibration verification range, s ys tem performance is una cceptable. In this case, correct the problem and repeat the test, or recalibrate (Section 9.7.4 ). 9.12.6 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 Table 9 - 1 shall be met; if not, a sample of diesel oil shall be diluted per the procedure in Section 9.10 and shall be used for the OPR test. 9.12.6.1 Analyze the appropriate OPR standard. 9.12.6.2 Compute the concentration of PAH in this standard per Section 9.14 . 9.12.6.3 Compare the concentration with the limits for ongoing precision and

recovery in Table 9 - 1 . If the concentration is in the range specified, the anal yt ical processes are in control and anal ys is 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 9.10.3 ). and repeat the ongoing precision and recovery test.9 - 12 9.12.6.4 Add results which pass the specification in Section 9.12.6.3 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 analy

te by calculating the average percent recovery ( R) and the standard deviation of percent recovery (Sr). Express the accuracy as a recovery

interval from R

– 2 Sr , to R + 2 Sr . For example, if R = 95% and S r = 5%, the accuracy is 85 to 105%. **9.13 Qualitative Identification**  9.13.1 Qualitative determination is accompli shed b y comparison of data from analysis of a

sample or blank with data from analy sis of the calibration verification standard (Section 9.12.5 ). 9.13.2 PAH is identified in the sample by the presence of peaks and/or an elevated baseli ne (hump) between the retention times of the naphthalene and indeno[1,2,3 - cd ]py rene peaks (Section 9.11.3.3 ), as shown in Figure 9 - 1 . The experience of the analy st shall weigh heavil y in interpretation of the chromatogram. **9.14 Quantitative Determination**  9.14.1 Using the data s ys tem, compute the concentration of the PAH detected in the solution

injected into the HPL C (in μg/mL) using the calibration factor (Section 9.7.4 ). 9.14.2 Concentration of PAH in oil: I f neat oil was anal yzed, the concentration of PAH in

the oil is determined using the following equation: [ 9 - 2 ] Where: C o = Concentration of PAH in the oil sample C p = Concentration of PAH measured (from Sections 9.11.4 and 9.14.1 ) C i = Concentration of oil in the solution injected into the HPL C (from

Sections 9.10.3.2 , 9.11.4 , and 9.14.1 ) 9.14.3 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 9.7.6.1 and using the calibration from Section 9.7.6.2 of this method, taking into account the dilution of these extracts (Section 9.10.2 ). 9.14.4 Concentration of PAH in oil from Meth od 1662: The PAH content of oil is

complicated b y the splitting and possible dilution of these extracts. 9.14.4.1 Concentration in undiluted extracts: This concentration is determined b y

Equation 9 - 3: [ 9 - 3 ] C o = V e × C p = 5 × I C p 1/5 × W T W T C o (mg/g) = C p (μg/mL)

C i (mg/mL)9 - 13 Where: C o = Concentration of PAH in the oil sample V e = Amount of extract split for HPL C anal ys is, in mL (1.0 mL) C p = Concentration of PAH measured W T = 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 9.14.4.2 Concentration in diluted extracts: I f the extract was diluted by a factor of 10 (Section 9.10.3 or 9.11.4 ), the concentration determined in Section 9.14.4.1 is multiplied by

10. 9.14.5 If the concentration is to be expressed as weight percent, C o is multiplied by 0.1. 9.14.6 Report results to three significant figures without correc tion for recovery . **9.15 Method Performance**  This method was validated in a single laboratory (Reference 6) using samples of hot - rolled drilling mud (Reference 7). **9.16 References**  1. “Carcinogens - Working With Carcinogens.” Department of Health, Education, and Welfare, Pu

blic Health Service, Centers for Disease Control [available through National Technical Information System, 5285 Port Royal Road, Springfield, VA 22161, document no. PB2772561: August 1977. 2. “OSHA Safety and Health Standards, General Industry [29 CFR 1910], Revised.” Occupational Safety and Health Administration, OSHA 2206. Washington, DC: January 1976. 3. “Safety in Academic Chemistry L aboratories (3rd Edition).” American Chemical Society Publication, Committee on Chemical Safety. Washington, DC: 1979. 4. “Handboo k of Anal yt ical Quality Control in Water and Wastewater Laboratories.” USEPA, EMSL - Ci, EPA - 600/4 - 79 - 019. Cincinnati, OH: March 1979. 5. “Standard Practice for Sampling Water,” ASTM Annual Book of Standards, Part 31, D337076, ASTM. Philadelphia, PA: 1980. 6. “Det ermination of Pol ynuclear Aromatic Hydrocarbons and Diesel b y 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 Analy tical Technologies Inc., 225 Commerce Drive, Fort Collins, CO 80524: March 29 1991, April 12, 1991, and August 18, 1992. 7. “Results of the API Study of Extraction and Analy sis Procedures for the Determination of Diesel Oil in Drilling Muds (Final Report).” American Petroleum Institute, Offshore9 - 14

Effluent Guidelines Steering Committee, Technology Work Group, Prepared by I .C. Raia, Shell Development Co. Houston, TX: April 18, 1991. **Table 9**  **- 1**  **. Performance Data and Method Acceptance Cri teria for PAH**  **Criterion Units**  **PAH in Diesel Oil a**  **Diesel Oil in Mud Extract**  **b Phenanthrene**  Minimum level c 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. e Test concentration of diesel oil = 1,250 μg/mL. f Test concentration in diluted extract = 1.25 mg/mL. g Test concentration = 0.50 μg/mL. **Table 9**  **- 2**  **. HPLC Calibration Data Analyte**  **Retention Time a**  **(m inutes)**  **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: T wo C 18 columns (150 mm long by 4.6 mm i.d., 300 angstroms) connected in series, preceded by one C 18 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 min utes. b Diesel oil is calibrated separately using a single point calibration (Section 9.7.6 ).9 - 15

**Figure 9**  **- 1**  **. Liquid Chromatography of the Three -**  **Component Standard and of No. 2 Di esel**  **Oil**10 - 1

**10. M**  **ETHOD FOR C**  **ONDUCTING A S**  **EDIMENT T**  **OXICITY T**  **EST WITH L** **EPTOCHEIRUS PLUMULOSUS**  **AND N**  **ON -**  **A QUEOUS**  **D RILLING**  **F LUIDS OR**  **S YNTHETIC**  **- BASED**  **D RILLING**  **M UDS**  **(EPA M**  **ETHOD 1644)**  **10.1 Summary of Method**  T his test method describe s the procedures for obtaining data regarding the effects of non aqueous drilling fluids (NAF s ) or s ynthetic based drilling muds (SBMs) on the marine amphipod, Leptocheirus plumulosus . EPA is regulating the sediment toxicity in NAFs and SBMs that are discharged from oil and gas extraction faciliti es in coastal and offshore waters as an indicator for toxic pollutants ( see 40 CFR 435.13, 435.15, 435.43, and 435.45). EPA established the use of this test and related limits to encourage the use of less toxic drilling fluids and additives. The sediment toxicity of the NAF - cuttings at the point of discharge is measured b y th is modified sediment toxicity test using a natural sediment and Leptocheirus plumulosus as the test organism. EPA promulgated the use of this method with revisions to the Oil and Gas E xtraction effluent guidelines ( U.S. EPA, 2001 ). This initial method was consistent with ASTM Standard Guide E 1367 - 92 (ASTM 1997). Subsequent to this rulemaking EPA updated this method in the NPDES permit for the Wes tern Gulf of Mexico (GMG290000, Appendix A) to be consistent with ASTM E 1367 - 99 (ASTM 2000) . This method is a re publication of the sediment toxicity test in NPDES p ermit for the Wes tern Gulf of Mexico (GMG290000, Appendix A). **10.2 Test Requirements and Materials**  10.2.1 Test Species (

Leptocheirus plumulosus ) 10.2.1.1 Description : Leptocheirus plumulosus is an infaunal amphipod that is

indigenous to subtidal regions along the east coast of the U.S. This amphipod constructs U - shaped burrows in the top 5 cm of fine sand to silty clay sediments (ASTM E 1367 - 99 ). As a re sult of its broad salinity and particle size tolerances, it is a desirable test species for a variety of toxicity testing programs. 10.2.1.2 Collection and Handling : In the field, amphipods can be collected using

sediment grab samplers such as Peterson and Ponar dredges. This species has been collected in various tributaries of the Chesapeake Bay for various toxicity testing programs (ASTM E 1367 - 99). The contents of each grab should be sieved through a 500 mesh screen. The sediment and organisms retained on the screen are gentl y rinsed into plastic buckets containing sediment and water from the collection site. These buckets are quickl y transported back to the laboratory and aerated. See ASTM E 1367 - 99 for more details on collection and handling. 10.2.1.3 Holding and Acclimation : Amphipods can be placed in aquaria containing

a 1 - 2 cm deep layer of collection site sediment that has been sieved through a 500 mesh screen. Amphipod density should be about 200 - 300 per 40 L aquarium with vigorous aeration. Two to three day s are suf ficient10 - 2 for acclimation to test conditions, and during this period a gradual change over from site water to test water is recommended (ASTM E 1367 - 99). 10.2.1.4 Environmental Tolerances : L. plumulosus is tolerant of a broad salinity

range, from near 0 to 33 g/kg (‰ ) (ASTM E 1367 - 99). This species has demonstrated up to 100% survival in >90% silt - clay sediment and an average of 85% survival in >95% sand/gravel sediment (ASTM E 1367 - 99). The ASTM data are consistent with data published from other studies indicating that L. plumulosus is tolerant of sandy and silty sediments. For example, Schlekat et al. (1992) noted a mean survival of 97.5% when L. plumulosus was exposed for 10 day s to field collected sediments ranging from 98.1% sand to 96.5% fines. Further, this spe cies was collected in the field in sediments consisting of 99.9% sand and 92.1% fines, indicating that L. plumulosus is a generalist and can thrive in a variety of sediment ty pes (Schlekat et al. 1992). However, the fine fraction of sediments in the Schlekat et al. study did not exceed 55% clay , indicating that the fine fraction was a mixture of silt and clay sized particles. Data from other studies indicated that this species is intolerant of sediments high in clay content. McGee et al. (1999) noted accept able survival when this species was exposed to Baltimore Harbor sediments containing up to 72% clay . However, Emery et al. (1997) noted significantl y reduced amphipod survival when L. plumulosus was exposed for 10 day s to Magothy

River, Maryland sediment ( amended with beach sand and kaolinite clay) containing 84%, 90%, and 100% clay . These data indicated that the tolerance range of this amphipod to clay content is between about 72 to 84%. As such, caution should be used when conducting L. plumulosus toxicity tests with sediments with clay content greater than about 70%. This should not have a significant impact on using this species in the NAF and SBM toxicity testing program, since field sediments seldom exceed 70% clay content (Suedel and Rodgers, 1991). 10.2.2 Culture Methods ( Leptocheirus plumulosus ) 10.2.2.1 Overview : Populations of L. plumulosus can be maintained through

several generations in the laboratory . The culture conditions specified in ASTM E 1367 - 92 and E 1367 - 99 are provided in Table 1 .10 - 3

**Table 10**  **- 1**  **. Culture conditions for L. plumulosus. Conditions listed are consistent with culture conditions specified in ASTM E 1367**  **- 92 and subsequent updates (E 1367**  **- 99)**  **Parameter Conditions**  Temperature 20±1 o C Salinity 20±1‰ Li ght Quality Wide - spectrum fluorescent or cool white lights Illuminance 500 - 1,000 lux Photoperiod 14h light: 10h dark Culture Chamber Shallow plastic tubs or glass aquaria Sediment Volume 1 - 2 cm depth at bottom of each culture chamber Renewal of overl yi ng water Static renewal (30 - 50% water volume change 2 - 4 times per week) Number of organisms/chamber Start with about 300 mixed age (mostl y immature and yo ung adults) individuals per chamber Feeding 0.1 to 0.5 g dry mixture 2 - 3 times per week ( see section 10.2.2.2) Aeration Continuous gentle to moderate aeration so as to not suspend sediments Overl yi ng Water Clean natural or s ynthetic seawater Overl yi ng water quality Salinity, temperature, and ammonia during culture start - up In addition to the conditions provided in Table 1, there are other conditions that are important in maintaining healthy L. plumulosus cultures, including identifying a source of clean sediment, sieving sediments before use, and the quality of the raw materials used to prepare their food. Preferabl y, the sediment and water used to culture the amphipods should be collected from the same area as those used in NAF tests. Fine - grained sediments have been shown to be suitable for this purpose (ASTM E 1367 - 92). Sediments collect ed in the field for culturing purposes should be first sieved through a 2,000 m mesh sieve to remove large debris and then through a 500 m mesh sieve to remove any indigenous organisms. L. plumulosus cultures should be maintained at 20±1 o C and 20±1‰ salin ity . If used, natural seawater should be filtered through a 5 micron filter before adding to cultures. New culture chambers should be aerated and allowed to equilibrate overnight before adding amphipods. Water used to start a new culture chamber should be renewed 24 h after initiation and before amphipods are added to culture chambers; otherwise, culture water should be renewed in conjunction with feeding. Cultures should be observed daily to ensure sufficient aeration. An abundance of amphipods on the sedi ment surface during daylight hours may indicate insufficient dissolved oxygen or overcrowding, as amphipods ty

picall y remain in their burrows unless they are searching for food or a mate. Culture chambers should be terminated and restarted with fresh sedim ent about once every 8 weeks to avoid overcrowding.10 - 4 Overcrowding may

lead to stress due to food or space limitations, and may also result in reduced female fecundity, thus reducing the relative health of the population of amphipods in a given culture chamb er. Cultures should be routinely inspected for the presence of indigenous worms and copepods, a microbial build - up, or black and sulfurous conditions beneath the sediment surface. Microbial growth appears as a white or gray

growth associated with uneaten f ood, and is indicative of overfeeding. Presence of indigenous species, excess microbial growth, or black and sulfurous conditions may necessitate discarding the affected culture chamber. 10.2.2.2 Feeding : A mixture of micro - algae, yeast, fish food flakes, alfalfa p owder,

ground cereal leaves, and shrimp maturation feed has been used to feed cultures (ASTM E 1367 - 92 and E 1367 - 99). Micro - algae used in culturing include Pseudoisochrysis paradoxa , Phaeodactylum tricornutum , and Tetraselmis suecica mixed in equal parts on a volume basis. These algae provide a source of fatty

acids that may

otherwise be absent in the diet. In practice, however, it should be noted that L. plumulosus has been cultured successfull y without the algal mixture and the yeast. The dry food portio n of the diet that has been used to successfull y culture L. plumulosus is shown in Table 2. **Table 10**  **- 2**  **. Dry food portion of the diet that has been used to successfully culture L.**  **plumulosus Dietary Component**  **Proportion** Fish food flakes ( e.g., TetraMin®) 48.0% Alfalfa powder 24% Ground cereal leaves (dried wheat leaves) 24% Shrimp maturation feed (e.g., Neo - Novum ®) 4.0%

This dry food mixture should be homogenized into a fine powder and fed to each culture chamber at a rate of 0.1 to 0.5 g two to three times per week, depending on culture densities. Overfeeding may result in microbial build - up on the sediment surface. The quality of the alfalfa powder and dried wheat leaves may

not be consistent among suppl iers, thus potentially adversel y affecting culture performance. Feeding should occur immediately

after culture water changes . 10.2.3 O btaining Amphipods for Starting a Test ( Leptocheirus plumulosus ) 10.2.3.1 Immature and adult amphipods of mixed sexes and approximately 3 to 5 mm in length (as measured from the base of the first antenna to the end of the third pleon segment along the dorsal surface) are used in toxicity tests, as they are easier to handle and count than younger individuals. Gravid females are not used in t esting.10 - 5 10.2.3.2 The 3 to 5 mm size class individuals are passed through a 1,000 m mesh

sieve and are retained on a 710 m mesh sieve. A 500 m mesh sieve has been used previously

to retain amphipods of the size needed, but this will result in a wider size range of amphipods used for testing. 10.2.3.3 In preliminary NAF experiments, this wide size range may have contributed to variability

in mortality

observed that was not present when the 710 m mesh sieve was used to retain amphipods in later experiments. The amphipods pas sing through a 1000 m mesh sieve but trapped on a 710 m mesh sieve provide a more uniform size range of animals that is thought to decrease the previously- observed variability in mortality . Laboratories are encouraged to use this ty pe of approach to reduce the variability in the size of amphipods used in the NAF/SBM testing program. 10.2.4 Control Sediments

10.2.4.1 Overview : Control sediment must meet certain minimum requirements to

be used in the NAF/SBM testing program . The primary requirement is that the sediment shoul d be able to support L. plumulosus in cultures for extended periods of time. This will ensure that the sediment is chemically nontoxic and that the physical and chemical characteristics of the sediment ( e.g. , total organic carbon, particle size distribution, and moisture content) are within the tolerance range of the test species. It is expected that separate aliquots of the culture sediment will also be used as a control sediment to be amended by NAFs or SBMs in the NAF/SBM testing program. Any modificatio ns made to the control sediments should be noted in the report . 10.2.4.2 Characterization : Sediments used in testing should be characterized for

total organic carbon (TOC), particle size distribution (sand, silt, and clay), and percent water content. These parameters have been shown to influence the results of NAF/SBM toxicity to L. plumulosus in initial experiments. Variations in these sediment characteristics should be quantified so that potential effects of these parameters on test results can be closely monitore d. 10.2.4.3 Collection : Control sediments should be collected from the amphipod

collection site or from another area that can provide a consistent source of sediment with characteristics within the tolerance range of L. plumulosus . Sediments showing evidence of ch emical contamination should not be used in the NAF/SBM testing program. Any site water overl yi ng the sediment should be retained so that fine particles suspended in the water can be re - combined with the sediment before use . Sediment salinity and temperatur e should be recorded at the time of collection. Sediment collected for use should be homogenized and a composite sample prepared for anal ys is for the parameters outlined above . 10.2.4.4 Sieving : Sediments collected in the field for culturing and testing purposes

s hould be first press - sieved through a 2,000 or similar mesh sieve to10 - 6 remove large debris and then through a 500 mesh sieve to remove any indigenous organisms. Sediments have also been press - sieved through a 250 to 350 mesh sieve prior to testing to aid in the enumeration of amphipods on a 500 mesh sieve at test termination . 10.2.4.5 Storage : The control sediment should be stored in plastic or glass

containers at 4 o C until test initiation. The sediment should be stored in the dark and should not be allowed to freez e or dry out during storage (ASTM E 1367 - 92) . 10.2.5 Test Water

10.2.5.1 Water used in the NAF/SBM testing program should be available in

sufficient quantities and be acceptable to L. plumulosus . The minimum requirement for acceptable water for use in the NAF/SBM testing program is that healthy

test organisms survive in the water, and in the water plus control sediment, for the duration of holding and testing without showing signs of disease or stress (ASTM E 1367 - 99). Another test for acceptability

of the test water would be its successful use in the culturing of L. plumulosus (with the control sediment). 10.2.5.2 Natural seawater or s ynthetic salt water can be used in the NAF/SBM

testing program . Natural salt water should be obtained from an uncontaminated area known to support a health y, reproducing population of L. plumulosus or similar sensitive species. Reconstituted salt water can be prepared b y adding commercially available sea salt in specified quantities. Natural seawater should be filtered b y passing through a 5 micron fi lter before use. The reader is referred to ASTM E 1367 - 92 or E 1367 - 99 for more information concerning test water. **10.3 Procedures**  10.3.1 Mixing NAFs or SBMs with Control Sediment

EPA Method 1646 describes the method that should be used for amending control sediments with NAFs and SBMs. The control sediment should be sieved and homogenized before wet to dry weight ratio and density

determinations are made and before NAFs are added to the control sediment. The following steps were given in EPA Method 1646 for mixing NAF s and SBMs with control sediments (parentheses were added here to provide additional information). 10.3.1.1 Determine the wet to dry weight ratio for the control sediment (three

replicates of 30 g each has been used successfull y) 10.3.1.2 Determine the density (g/ml) of th e control sediment (three replicates of >25 ml is suitable for this purpose); 10.3.1.3 Determine the amount of NAF or SBM needed to obtain a desired test

concentration;10 - 7 10.3.1.4 Determine the amount of wet sediment required; 10.3.1.5 Determine the amount of dry sediment in kilogram s for each test concentration; 10.3.1.6 Determine the amount of NAF or SBM required to amend the control

sediment at each test concentration; 10.3.1.7 Mix NAF or SBM with control sediment; 10.3.1.8 Test for homogeneity of NAF or SBM in sediment, and; 10.3.1.9 Mix sufficient quantities of NAF or SBM with control sediment for each

treatment of amended or spiked sediment. 10.3.2 Estimate of Require NAF and SBM Required

The six steps given above for NAFs can also be applied to SBMs, except that the third bullet in Step 3 requires a measurement of the density of the SBM. The density of the SBM can then be used to estimate the quantity required for the desired test concentration. Refer to the formulas below for NAF and SBM calculations: [ 10 - 1 ] SBM Required (g) = [Conc. Desired (ml/kg) ] x [Dry Weight Sediment (kg) x [SBM Density (g/ml)] [10 - 2] See 40 CFR 435.13, 435.15, 435.43, and 435.45 for more information on this procedure. 10.3.3 Mixing Procedure

Mixing the NAF or SBM with the control sediment should be accomplished by foll owing these steps. The control sediment alone should also be subjected to the mixing procedure to ensure mixing has no effect on sediment toxicity . 10.3.3.1 Place appropriate amounts of weighed NAF or SBM into a stainless steel

mixing bowl. 10.3.3.2 Tare the mixing bowl we ight. 10.3.3.3 Add appropriate amount of control sediment. 10.3.3.4 Mix for 9 to15 minutes with a hand - held mixer equipped with stainless

steel blades (e.g., KitchenAid Model KHM6). 10.3.3.5 As appropriate, test mixing homogeneity as described in Section 10.3.4. 10.3.4 Homogeneity

of Mixin g NAF Required (g) = [Conc. Desired (mg/kg)] × [Dry Weight Sediment (g)] 1000 g/kg 1000 mg/g10 - 8 10.3.4.1 Tests for homogeneity of mixing should be performed, preferabl y in the

procedure development phase ( see 40 CFR 435.13, 435.15, 435.43, and 435.45 ) by

each laboratory

performing NAF/SBM toxicity testing. This is to ensure that the NAF or SBM, which can be difficult to homogenize with control sediments, can be evenl y mixed with the control sediment by each testing laboratory . 10.3.4.2 EPA Method 1646 specifies that the coefficient of variation (CV) for a

minimum of three replicate samples of the NAF/control sediment mixture must be less than 20%. Determinations of CV should be based on total petroleum hydrocarbon (TPH) content of the NAF or SBM as measured by EPA Methods 3550A and 8015M. If the initial CV is 20%, then the NAF/SBM - sediment mixture must be re - mixed an d reanal yz ed until the 20% CV limit is achieved. 10.3.4.3 Homogeneity

measurements should be made on the lowest and highest NAF concentrations for a given test. Laboratories should validate mixing efficiency via TPH measurements (as outlined above) of the low and high NAF concentrations. The homogeneity measurements should be made at least once per ye ar. **10.4 Recommended Test Condition**  **s** 10.4.1 The recommended test conditions for conducting the 10 - day or 96 - hr sediment toxicity test with L. plumulosus are summarized in Table 3 and are consistent with methods presented in ASTM E 1367 - 92 and subsequent updates (E 1367 - 99). Tests should be conducted at 20±1 o C and 20±1‰ salinity with a 14h light; 10 h dark photoperiod at approximately 500 - 1,000 lux (or about 46 to 93 footcandles). T est chambers are 1 - L glass containers with about a 10 cm inside diameter opening (or similar glass containers) that can contain about 150 ml sediment and 600 ml overlying water to achieve a 4:1 (v/v) water to sediment ratio. 10.4.2 There are five (5) test concentrations plus a control for each NAF and SBM test. Five

(5) replicates are included for the control sediment (E 1367 - 99) and for each test concentration. 10.4.3 The control sediment/test material mixture and test water should be added to test

chambers the day

bef ore amphipods are added. This will allow for suspended particles to settle and allow time for equilibration of temperature and the sediment water interface. 10.4.4 After the overnight equilibration period, amphipods are randomly distributed to each test chamber. Twenty amphipods are added to each replicate and there are five replicates per test treatment. 10.4.5 Amphipods caught on the water surface can be pushed under with a glass rod.

Individuals that have not burrowed within 5 to 10 minutes can be replaced, unless they are exhibiting an avoidance response. Amphipods are not removed at any time during the course of the toxicity test even if they

appear dead. Test water is not10 - 9 renewed (i.e., static) and the amphipods are not fed during the exposure period. The toxicity test is terminated after 96 hours or 10 day s for SBMs and NAFs respectivel y. 10.4.6 Temperature, salinity , pH, and dissolved oxygen (DO) should be monitored daily . 10.4.7 Ammonia should also be monitored in overlying water to ensure that the

concentrations of this cons tituent do not exceed the tolerance range of the test species. For L. plumulosus , this is about 60 mg/L (as total ammonia) at pH 7.7 in 10 - day tests (U.S. EPA, 1994). Ammonia has not been a problem in initial L. plumulosus 96 - hr and 10 - day

tests with vario us NAFs. **Table 10**  **- 3**  **. Conditions for conducting 96 -**  **hour NAF and 10 -**  **day SBM sediment toxicity tests with**  **L. plumulosus . Conditions listed are consistent with test conditions specified in**  **ASTM E 1367 -**  **92 and subs equent updates (E 1367**  **- 99) unless otherwise noted**  **Parameter Conditions**  Test Ty pe Static whole sediment toxicity test Temperature 20±1 o C Salinity 20±1‰ Li ght Quality Wide - spectrum fluorescent or cool white lights Illuminance 500 - 1,000 lux Photoperiod 14h light: 10h dark * Test Chamber 1 - L gl ass beaker or jar Sediment Volume 150 ml (2 cm depth) Overl yi ng water volume 600 ml (4:1 [v/v] water to sediment ratio) Renewal of overl yi ng water None Size and life stage of amphipods 3 - 5 mm; immature and adu lt Number of organisms/chamber 20 Number of test concentrations 5 Number of replicate chambers/treatment 5 in both controls and test treatments Feeding None Aeration Water in each test chamber should be aerated throughout the test. Overl yi ng Water Cl ean natural or s ynthetic seawater Overl yi ng water quality Temperature, salinity , pH, and D.O. daily ; ammonia, as needed Test duration 96 hours or 10 day s Endpoint Survival Test acceptability Minimum mean control survival of 90% and satisfaction of crit eria outlined in Table 4 . * **Note:** Although ASTM E 1367 specifies 16h light:8h dark, the photoperiod was changed to 14h light:10h dark to be consistent with the Mysidopsis bahia bioassay for drilling fluids ( EPA Method 1619 ).10 - 10

**10.5 Biological Data**  10.5.1 Mortality

is the endpoint for L. plumulosus at the end of the exposure period. At test termination, the contents of each test chamber (amphipods plus test sediment) are sieved through a 500 mesh screen to remove amphipods. 10.5.2 Material retained on the screen should be rin sed into a sorting tray with clean salt water. 10.5.3 The total numbers of live and dead amphipods should be recorded. 10.5.4 Missing animals are presumed to have died and decomposed during the test and

disintegrated. 10.5.5 Amphipods should be counted alive if there are any signs of movement, such as a

neuromuscular pleopod twitch (ASTM E 1367 - 99). Gentle prodding may be used to elicit movement. **10.6 Quality Control**  10.6.1 Table 4 provides the acceptability requirements for the 10 - day NAF and 96 - hr SBM test. The primary

acceptability requirement for NAF testing is as follows. 10.6.2 A toxicity

test is unacceptable if more than a total of 10% of the control organisms die, or if the coefficient of variation (CV) of control survival is equal to or greater than 40%. 10.6.3 If this acceptability requirem ent is not met, then the data should be discarded and the experiment repeated. 10.6.4 If this requirement is met, then the other acceptability requirements in Table 4 should be reviewed and a determination made as to the acceptability of the data.10 - 11

**Table 10**  **- 4**  **. Test acceptability requirements for 10 -**  **day NAF and 96 -**  **hr SBM tests with L.**  **plumulosus . Requirements listed are consistent with those specified in ASTM E 1367**  **- 92**  **and subsequent updates (E 1367 -**  **99)** Ten - day NAF and 96 - hr SBM toxicity tests should usually

be considered unacceptable if one or more of the following occurred :*

 A 10 - day

NAF and 96 - hr SBM toxicity tests are unacceptable if more than a total of 10% of the control organisms die, or if the coefficient of variation (CV) of control survival is equal to or greater than 40%.  All test chambers were not identical.  Test organisms were not randomly or impartially

distributed to test chambers.  Required reference standard was not included in the test.  All test anim als were not from the same population, were not all of the same species, or were not of acceptable quality .  Amphipods from a wild population were maintained in the laboratory for more than two weeks, unless the effects of prolonged maintenance in the laboratory has been shown to have no significant effect on sensitivity .  The test organisms were not acclimated at the test temperature and salinity at least 48 hours before they

were placed in the test chambers.  Temperature and dissolved oxygen concentrations w ere not measured

* **Note:** These guidelines are not identical to those listed ASTM E 1367 in part because some acceptability guidelines listed in ASTM E1367 - 92 are not applicable or practical for the NAF/SBM toxicity testing program. **10.7 Reference Tests**  10.7.1 A sin gle toxicity test will be used to determine satisfactory laboratory

performance and to determine whether an NAF or SBM can be discharged as it adheres to drill cuttings. The reference toxicant for the NAF test will be either a C 16 - C 18 internal olefin reference standard or a C 12 - C 14 or C 8 ester. 10.7.2 The reference toxicant for the SBM testing program will be a C 16 - C 18 internal olefin

SBM which has also been specified for determining pass/fail for SBMs. The C 16 - C 18 internal olefin SBM is a 65/35 blend, proportion ed by mass, of hexadecene and octadecene, respectively

(see 40 CFR 435.11(rr). 10.7.3 These reference toxicity tests will be conducted in conjunction with all NAF or SBM tests to discern possible changes in the condition of the L. plumulosus population used in t esting. The reference toxicant test must be conducted concurrentl y with each sample or batch of samples and at a minimum should be conducted at least monthly . Control charts of this reference standard should be maintained to perform statistical anal ys es, h elp understand the inherent variability in the reference test, and for long term quality

control. Test conditions for the reference test should follow the experimental conditions presented in Table 3. 10.7.4 The reference toxicant test should be performed concurrentl y- and under the same

conditions as the NAF or SBM test.10 - 12

10.7.5 The reference toxicant test should be conducted so that control limits (ty pically set at 2 standard deviations) can be established (U.S. EPA, 1994). 10.7.6 If the reference test L C 50 falls outside of this range of control limits generated on the

most recent test data points, then the sensitivity of L. plumulosus and the credibility of the test results are considered suspect. In this case, the test procedure should be examined and the test repeated with a different batch of amphipods. A sediment test should not automatically

be judged unacceptable if the reference test L C 50 falls outside the expected range or if the control in the reference toxicity test exceeds 10%. The width of the control limits and al l performance criteria listed in Table 4 should be considered when determining the acceptability of a given NAF or SBM test. **10.8 Interpretation of Result**  10.8.1 Procedures presented in this test method are used to calculate point estimates, or L C 50

values. The LC 50 value and 95% confidence limits of the NAF tests should be calculated on the basis of milligrams of NAF per kg dry control sediment (mg/kg) and amphipod mortality . 10.8.2 The L C 50 value and 95% confidence limits of the NAF tests should be calculated on

the basis of milliliters of NAF per kg dry control sediment (ml/kg) and amphipod mortality . 10.8.3 A variety of methods can be used to calculate an LC 50 value and its 95% confidence

limits, including probit, moving average, trimmed Spearman - Karber and Litchfield Wilcoxon methods (ASTM E 1367 - 99). The method used should take into account the number of partial kills, the number of test chambers per treatment (5), and the number of amphipods per test chamber (20). 10.8.4 The only NAF - drill cuttings that can be discharge are cutting s coated with NAF s that

are as toxic or less toxic, but not more toxic, than the reference NAF (C 16 - C 18 internal olefin or C 12 - C 14 or C 8 ester) as measured b y LC 50 . This limitation is expressed in 40 CFR 435.13, 435.15, 435.43, and 435.45 . [ 10 - 3 ] 10.8.5 The only SB M - drill cuttings that can be discharge are cuttings coated with SBMs that

are as toxic or less toxic, but not more toxic, than the reference SB M (C 16 - C 18 internal olefin or C 12 - C 14 or C 8 ester) as measured b y LC 50 . This limitation is expressed in 40 CFR 435.13, 435.15, 435.43, and 435.45 . [ 10 - 4 ] 10 - day L C 50 Reference Material ≤ 1.0 10 - day L C 50 NAF

96 - hr L C 50 Reference Drilling Fluid ≤ 1 .0 10 - day L C 50 SBM10 - 13

10.8.6 T he NAF or SBM data should be interpreted b y comparing to the reference toxicant

test L C 50 value and whether it exceeds th e limitations in 40 CFR 435.13, 435.15, 435.43, an d 435.45 . **10.9 Re**  **ferences** 10.9.1 American Society for Testing and Materials (ASTM). 1997. Standard Guide for

Conducting 10 - day

Static Sediment Toxicity Tests with Marine and Estuarine Amphipods. E 1367 - 92. Annual Book of ASTM Standards, Vol. 11.05. 10.9.2 American Society for Testing and Materials (ASTM). 2000. Standard Guide for

Conducting 10 - day

Static Sediment Toxicity Tests with Marine and Estuarine Amphipods. E 1367 - 99. Annual Book of ASTM Standards, Vol. 11.05. 10.9.3 Emery , V.L., D.W. Moore, B.R. Gray , B.M. Duke, A.B. Gibs on, R.B. Wright and

J.D. Farrar. 1997. Development of a chronic sublethal sediment bioassay using the estuarine amphipod Leptocheirus plumulosus (Shoemaker). Environ. Toxicol. Chem. 16:1912 - 1920. 10.9.4 McGee, B.L. D.J. Fisher, L .T. Yonkos, G.P. Ziegler and S. Turley . 1999. Assessment

of sediment contamination, acute toxicity , and population viability of the estuarine amphipod Leptocheirus plumulosus in Baltimore Harbor, Maryland, USA. Environ. Toxicol. Chem. 18:2151 - 2160. 10.9.5 Schlekat, C.E., B.L. McGee and E. Reinharz. 1992. Testing sediment toxicity in Chesapeake Bay

with the amphipod Leptocheirus plumulosus : an evaluation. Environ. Toxicol. Chem. 11:225 - 236. 10.9.6 Suedel, B.C. and J.H. Rodgers, Jr. 1991. Variability of bottom sediment

characteristics of the continental Un ited States. Water Res. Bull. 27:101 - 109. 10.9.7 U.S. EPA, 1994. Methods for Assessing the Toxicity of Sediment - associated Contaminants with Estuarine and Marine Amphipods. EPA/600/R - 94/025. USEPA Office of Research and Development, June 1994. 10.9.8 U.S. EPA, 2001. Eff luent Limitations Guidelines and New Source Performance Standards for the Oil and Gas Extraction Point Source Category ; OMB Approval Under the Paperwork Reduction Act: Technical Amendment, Federal Register, Volume 66, Page 6849 - 6919, January 22 nd

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