United States
Environmental Protection
Agency
Office of Water
4303
EPA-821-B-98-019
February 1999
&EPA
Environmental Assessment of Proposed
Effluent Limitations Guidelines and Standards
for Synthetic-Based Drilling Fluids and other
Non-Aqueous Drilling Fluids in the Oil and
Gas Extraction Point Source Category
-------
EPA-821-B-98-019
ENVIRONMENTAL ASSESSMENT
OF
PROPOSED EFFLUENT LIMITATIONS GUIDELINES AND
STANDARDS FOR SYNTHETIC-BASED DRILLING FLUIDS AND
OTHER NON-AQUEOUS DRILLING FLUIDS IN THE
OIL AND GAS EXTRACTION POINT SOURCE CATEGORY
FEBRUARY 1999
Office of Water
Office of Science and Technology
Engineering and Analysis Division
U.S. Environmental Protection Agency
Washington, DC 20460
-------
CONTENTS
EXECUTIVE SUMMARY ES-1
1. INTRODUCTION 1-1
2. DESCRIPTION OF REGULATORY OPTIONS 2-1
3. CHARACTERIZATION
3.1 Industry Characterization 3-1
3.2 Wastestream Characterization 3-2
3.3 Receiving Water Characterization 3-8
3.3.1 GulfofMexico 3-8
3.3.2 Cook Inlet, Alaska 3-9
3.3.3 Offshore California 3-10
3.4 Recreational and Commercial Fisheries 3-11
3.4.1 Gulf ofMexico 3-11
3.4.2 Cook Inlet, Alaska 3-11
3.4.3 Offshore California 3-13
4. WATER QUALITY ASSESSMENT
4.1 Introduction 4-1
4.2 Surface Water 4-2
4.2.1 Gulf ofMexico 4-6
4.2.2 Cook Inlet, Alaska 4-6
4.2.3 Offshore California 4-9
4.3 Sediment Pore Water Quality 4-12
4.3.1 Gulf ofMexico 4-12
4.3.2 Cook Inlet, Alaska and Offshore California 4-17
4.4 Sediment Guidelines for the Protection of Benthic Organisms 4-32
5. HUMAN HEALTH RISKS
5.1 Introduction 5-1
5.2 Recreational Fisheries Tissue Concentrations 5-1
5.2.1 Gulf ofMexico 5-2
5.2.2 Cook Inlet, Alaska 5-4
5.2.3 Offshore California 5-4
5.3 Commercial Fisheries Shrimp Tissue Concentrations 5-5
5.3.1 Gulf ofMexico 5-6
-------
5.3.2 Cook Inlet, Alaska 5-6
5.3.3 Offshore California 5-7
5.4 Noncarcinogenic and Carcinogenic Risk - Recreational Fisheries 5-8
5.4.1 GulfofMexico 5-10
5.4.2 Cook Inlet, Alaska 5-10
5.4.3 Offshore California 5-16
5.5 Noncarcinogenic and Carcinogenic Risk - Commercial Shrimp 5-16
5.5.1 Gulf ofMexico 5-19
5.5.2 Cook Inlet, Alaska 5-20
5.5.3 Offshore California 5-25
6. TOXICITY
6.1 Introduction 6-1
6.2 Summaries of Identified Articles Containing Toxicity Information 6-2
6.3 Summary 6-9
7. BIOACCUMULATION
7.1 Introduction 7-1
7.2 Summary of Data 7-1
7.3 Summaries of Identified Reports Containing Bioaccumulati on Information .... 7-2
8. BIODEGRADATION
8.1 Introduction 8-1
8.2 Biodegradation Test Methods 8-1
8.3 Biodegradability Results 8-5
8.3.1 Aqueous Phase Tests 8-5
8.3.2 Sedimentary Phase Tests 8-10
8.4 Discussion and Conclusions 8-12
9. SEABED SURVEYS
9.1 Background 9-1
9.2 Assessment of Field Studies 9-2
9.2.1 Findings 9-2
9.2.2 Study Limitations 9-13
9.3 Summary of Relevant Field Studies 9-17
9.3.1 Water-Based Fluids 9-17
9.3.2 Synthetic-Based Fluids 9-44
10. BIBLIOGRAPHY 10-1
-------
Ill
Appendix A Calculation of Gulf of Mexico Shrimp Catch A-l
Appendix B Reanalysis of Water Quality Criteria Assessment B-l
Appendix C Brandsma, 1996; Figure 2 C-l
Appendix D Calculation of Sediment Pore Water Concentrations for Water Quality
Analyses D-l
Appendix E Calculation of Finfish Tissue Pollutant Concentrations E-l
Appendix F Calculation of Sediment Pore Water Concentrations for Shrimp Tissue
Pollutant Concentration Calculation F-l
Appendix G Calculation of Shrimp Tissue Pollutant Concentrations G-l
-------
IV
EXHIBITS
Exhibit 3-1 Estimated Number of Wells Drilled Annually By Drilling Fluid 3-2
Exhibit 3-2 Volume of SBF-Cuttings Generated Per Model Well 3-5
Exhibit 3-3 Model Well Characteristics 3-6
Exhibit 3-4 Heavy Metal Concentrations In Barite 3-7
Exhibit 3-5 Formation Oil Characteristics 3-8
Exhibit 3-6 Gulf of Mexico Recreational Fisheries Catch 3-12
Exhibit 3-7 Gulf of Mexico Commercial Shrimp Catch 3-12
Exhibit 4-1 Federal Water Quality Criteria 4-3
Exhibit 4-2 Summary of Water Column Water Quality Analyses 4-5
Exhibit 4-3 Water Column Pollutant Concentrations - Gulf of Mexico,
Current Technology 4-7
Exhibit 4-4 Water Column Pollutant Concentrations - Gulf of Mexico,
Discharge Option 4-8
Exhibit 4-5 Alaska State Water Quality Standards 4-9
Exhibit 4-6 Water Column Pollutant Concentrations - Cook Inlet, Alaska,
Current Technology 4-10
Exhibit 4-7 Water Column Pollutant Concentrations - Cook Inlet, Alaska,
Discharge Option 4-11
Exhibit 4-8 Water Column Pollutant Concentrations - Offshore California,
Current Technology 4-13
Exhibit 4-9 Water Column Pollutant Concentrations - Offshore California,
Discharge Option 4-14
Exhibit 4-10 Summary of Pore Water Quality Analyses - Factors by Which
Criteria are Exceeded 4-15
Exhibit 4-11 Summary of Synthetic Base Fluid Concentrations at 100 Meters 4-16
Exhibit 4-12 Trace Metal Leach Factors and Organic Pollutant
Partition Coefficients 4-18
Exhibit 4-13 Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Development Model Well, Current Technology 4-19
Exhibit 4-14 Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Exploratory Model Well, Current Technology 4-20
Exhibit 4-15 Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Development Model Well, Current Technology 4-21
Exhibit 4-16 Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Exploratory Model Well, Current Technology 4-22
Exhibit 4-17 Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Development Model Well, Discharge Option 4-23
-------
Exhibit 4-18 Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Exploratory Model Well, Discharge Option 4-24
Exhibit 4-19 Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Development Model Well, Discharge Option 4-25
Exhibit 4-20 Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Exploratory Model Well, Discharge Option 4-26
Exhibit 4-21 Pore Water Pollutant Concentrations - California Deep Water
Development Model Well, Current Technology 4-28
Exhibit 4-22 Pore Water Pollutant Concentrations - Cook Inlet, Alaska and Offshore
California Shallow Water Development Model Well,
Current Technology 4-29
Exhibit 4-23 Pore Water Pollutant Concentrations - California Deep Water
Development Model Well, Discharge Option 4-30
Exhibit 4-24 Pore Water Pollutant Concentrations - Cook Inlet, Alaska and Offshore
California Shallow Water Development Model Well,
Discharge Option 4-31
Exhibit 4-25 Sediment Guidelines Analysis - Gulf of Mexico, Current Technology . . . 4-33
Exhibit 4-26 Sediment Guidelines Analysis - Gulf of Mexico, Discharge Option 4-34
Exhibit 4-27 Sediment Guidelines Analysis - Cook Inlet, Alaska and Offshore
California 4-35
Exhibit 5-1 Pollutant-Specific Bioconcentration Factors 5-3
Exhibit 5-2 Calculation of Average Dilutions within Gulf of Mexico Mixing Zone ... 5-3
Exhibit 5-3 Calculation of Average Dilutions within Cook Inlet, Alaska
and Offshore California Mixing Zones 5-4
Exhibit 5-4 Arithmetically-Averaged Concentration Data 5-7
Exhibit 5-5 Oral Reference Doses and Slope Factors 5-9
Exhibit 5-6 Summary of Finfish Health Risks 5-11
Exhibit 5-7 Recreational Finfish Health Risks - Gulf of Mexico, Current
Technology 5-12
Exhibit 5-8 Recreational Finfish Health Risks - Gulf of Mexico, Discharge Option .. 5-13
Exhibit 5-9 Recreational Finfish Health Risks - Cook Inlet, Alaska, Current
Technology 5-14
Exhibit 5-10 Recreational Finfish Health Risks - Cook Inlet, Alaska, Discharge
Option 5-15
Exhibit 5-11 Recreational Finfish Health Risks - Offshore California, Current
Technology 5-17
Exhibit 5-12 Recreational Finfish Health Risks - Offshore California, Discharge
Option 5-18
Exhibit 5-13 Summary of Shrimp Health Risks 5-19
Exhibit 5-14 Calculation of Shrimp Catch Impacted in the Gulf of Mexico 5-20
-------
VI
Exhibit 5-15 Commercial Shrimp Health Risks - Gulf of Mexico, Shallow Water
Development Model Well, Current Technology 5-21
Exhibit 5-16 Commercial Shrimp Health Risks - Gulf of Mexico, Shallow
Water Development Model Well, Discharge Option 5-22
Exhibit 5-17 Commercial Shrimp Health Risks - Gulf of Mexico, Shallow
Water Exploratory Model Well, Current Technology 5-23
Exhibit 5-18 Commercial Shrimp Health Risks - Gulf of Mexico, Shallow
Water Exploratory Model Well, Discharge Option 5-24
Exhibit 5-19 Commercial Shrimp Health Risks - Offshore California, Shallow
Development Model Well, Current Technology 5-26
Exhibit 5-20 Commercial Shrimp Health Risks - Offshore California, Shallow
Development Model Well, Discharge Option 5-27
Exhibit 6-1 Reported Toxicities of Synthetic-Based Fluids 6-3
Exhibit 7-1 Bioaccumulation Data for Synthetic Fluids and Mineral Oil Muds 7-3
Exhibit 8-1 OECD 301D: 28-Day Closed Bottle Test 8-2
Exhibit 8-2 ISO 11734: "Water Quality-Evaluation of the "Ultimate" Anaerobic
Biodegradability of Organic Compounds in Digested Sludge-Method
By Measurement of the Biogas Production" 8-3
Exhibit 8-3 NIVA Protocol for Simulated Seabed Biodegradation Study 8-4
Exhibit 8-4 SOAEFD Protocol for Solid-Phase Test System for Degradation
of Synthetic Mud Base Fluid 8-4
Exhibit 8-5 Summary of Aquatic Phase Aerobic Laboratory Biodegradation Test
Conditions and Their Suitability for Poorly Soluble, Volatile, and
Surface Active Compounds 8-6
Exhibit 8-6 Summary of Test Procedures Used in the Biodegradation Testing
of Synthetic-Based Drilling Fluids 8-7
Exhibit 8-7 Ranking of Aqueous Phase Biodegradation Methods and Test Results ... 8-9
Exhibit 8-8 Average Percentage Biodegradation Using BODIS Seawater and
Freshwater Procedures for an Ester and Acetal 8-9
Exhibit 8-9 Anaerobic Biodegradability of Test Chemicals Examined in the
ECETOC Screening Test 8-11
Exhibit 8-10 Percentage Biodegradation of Base Fluids in Drilling Fluids Measured
by Various Test Methods 8-12
Exhibit 9-1 Marine Studies of Water-Based Drilling Fluid Impacts 9-3
Exhibit 9-2 Marine Studies of Synthetic-Based Drilling Fluid Impacts 9-9
Exhibit 9-3 Water-Based and Synthetic-Based Drilling Fluid Impact Comparison ... 9-14
-------
Vll
Exhibit 9-4 Comparison of Sampling Area of Averages for Number of Species,
Organisms, and Species Diversity for the Survey Periods 9-24
Exhibit 9-5 Summary of Benthic Data Collected at Test Plots 9-29
Exhibit 9-6 Comparison of Abundance Data Collected at Test Plots 9-30
Exhibit 9-7 1990 and 1991 North Sea Benthic Community Data 9-45
Exhibit 9-8 Sediment TPH vs. Distance from Drill Site 9-47
Exhibit 9-9 Sediment Barium vs. Distance from Drill Site 9-47
-------
ES-1
EXECUTIVE SUMMARY
A. Background
This environmental assessment consists of an evaluation of the ecological and indirect
human health impacts for the discharge of cuttings contaminated with synthetic-based drilling
fluids (SBFs) with respect to discharges to water. In addition, this document describes the
environmental characteristics of SBF drilling wastes (e.g., toxicity, bioaccumulation,
biodegradation), the types of anticipated impacts, and the pollutant modeling results for water
column concentrations, pore water concentrations, and human health effects via consumption of
affected seafood. This document does not consider the potential non-water quality
environmental effects associated with the proposed rule.
The geographic areas considered under this rule are those where EPA knows SBFs are
currently used and those where EPA projects SBFs will be used as a result of the SBF Effluent
Guidelines. This includes the Gulf of Mexico, offshore California, and Cook Inlet, Alaska. It is
these three geographic areas where EPA projects that pollutant loadings will change as a result of
the proposed rule and are included in the various environmental impact analyses of this
environmental assessment.
EPA considered two regulatory options for the SBF rule: a discharge option and a zero
discharge option. While discharge of SBF-cuttings would be allowed under the discharge option,
discharge of SBFs not associated with drill cuttings would not be allowed. Since zero discharge
of neat SBFs is also current industry practice due to the value of SBFs recovered and reused, it
has no incremental environmental impact.
In the zero discharge option, both the SBF-cuttings as well as neat SBF would be
prohibited from discharge. Because the zero discharge option results in the absence of
discharged pollutants, the environmental assessment analyses did not require calculations to
demonstrate zero environmental impacts.
For the purposes of this environmental assessment, EPA projected that the only material
effect that the discharge option of the proposed SBF regulation would have on the SBF-cuttings
wastestream would be to reduce the amount of synthetic base fluid on the drill cuttings from 11%
to 7%. This reduction is based on the performance of the current shale shaker technology (11%
base fluid retention), and the proposed BAT technology (7% base fluid retention). The model
BAT technology consists of a vibrating centrifuge which recovers additional SBF from the SBF-
cuttings. For the purpose of this environmental assessment, EPA does not project that the other
proposed limitations, such as the stock base fluid limitations, would materially affect the
discharge.
-------
ES-2
Thus, under the discharge option, the amount of pollutant discharge is reduced but the
types of pollutants are not affected. Also, EPA projects that the number of wells using SBF will
increase. In the Gulf of Mexico, EPA projects that under current requirements 113 SBF wells
annually will be drilled in the Gulf of Mexico, while under the proposed SBF Effluent Guidelines
136 SBF wells will be drilled annually. Since all of the analyses, except for exposure by way of
shrimp consumption, are on a site specific basis, the number of wells discharging does not affect
the conclusions of this environmental assessment. Only the quantity and types of pollutants
discharged at a particular site affect the conclusions (except shrimp consumption analysis).
In offshore California and Cook Inlet, Alaska, SBFs are not used under current
requirements but EPA projects that the wells currently drilled with OBFs will convert to SBFs as
a result of the SBF Effluent Guidelines. To show the effect of the model BAT technology,
however, this environmental assessment determines "current technology" impacts in offshore
California and Cook Inlet as if the wells projected to convert to SBF currently discharge SBF-
cuttings at 11% base fluid retention. This is compared to the SBF-cuttings discharges projected
to occur at 7% base fluid retention as a result of the proposed SBF rule.
The amount of pollutants discharged and impacting the receiving water depends on the
efficiency of the solids control equipment, here expressed as either 11% or 7% retention on
cuttings, and the volume of cuttings generated from drilling a given well or well interval. The
volume of cuttings generated while drilling the SBF intervals of a well depends on the type of
well (development or production) and the water depth. According to analyses of the model wells
provided by industry representatives, wells drilled in less than 1,000 feet of water are estimated
to generate 565 barrels of cuttings for a development well and 1,184 barrels of cuttings for an
exploratory well. Wells drilled in water greater than 1,000 feet deep are estimated to generate
855 barrels of cuttings for a development well, and 1,901 cuttings for an exploratory well. These
values assume 7.5 percent washout, based on the rule of thumb reported by industry
representatives of 5 to 10 percent washout when drilling with SBF. Washout, that is, the caving
in or stuffing off of the well bore, increases hole volume and increases the amount of cuttings
generated when drilling a well.
EPA has adopted the Minerals Management Service (MMS) and industry categorization of
drilling wells according to type of drilling operation, i.e., exploratory or development, and water
depth. Deep water wells are defined as wells that are drilled in water greater than 1,000 feet deep
whereas shallow water wells are drilled in water less than 1,000 feet deep. Using other federal
and state government agency data, EPA determined the number of wells drilled annually using
SBFs, OBFs, and water-based drilling fluids (WBFs).
-------
ES-3
B. Water Quality Assessment
EPA based the methodologies for assessing both surface water and pore water quality
impacts of SBF-cuttings on the methodologies used to assess the discharge of water-based fluids
and cuttings (WBF-cuttings) for the offshore effluent limitations guidelines (ELG). In the
current SBF-cuttings discharge impact analysis, surface water quality assessments rely on
modeling data presented in a study of the post-discharge transport behavior of oil and solids from
oil-based fluids cuttings (OBF-cuttings). Due to the similar hydrophobic and physical properties
between SBFs and OBFs, EPA assumes that dispersion behavior of SBF-cuttings is similar to
that of OBF-cuttings.
In general, the methodology consists of modeling incremental water column and pore water
concentrations and comparing them to Federal water quality criteria/toxic values for marine
acute, marine chronic, and human health protection. Additionally, EPA used the proposed
sediment guidelines for protection of benthic organisms to assess potential impacts from a group
of select metals in pore water. Note that all of these comparisons are performed only for those
pollutants for which EPA has numeric criteria. Those pollutants include priority and
nonconventional pollutants associated with the drilling fluid barite and with contamination by
formation (crude) oil, but do not include synthetic base fluids themselves.
Surface Water Quality
Results of the water quality analyses for the Gulf of Mexico, offshore California, and Cook
Inlet show that there are no exceedances of Federal water quality criteria in either the current
technology (11% retention) or discharge option (7% retention) scenarios.
Pore Water Quality
EPA calculated sediment pollutant levels based on the assumption of a uniform distribution
of the mass loadings of pollutants from model operations into a defined area of impact.
To assess the pore water quality impacts of the discharge of SBF-cuttings on the benthic
environment, EPA projected the pollutant concentrations in the pore water for the model wells
under the two discharge scenarios at the edge of a 100-meter mixing zone. EPA then compared
these projected pore water concentrations of pollutants from the SBF-cuttings to Federal water
quality criteria to determine the number of exceedances and the magnitude of each exceedance.
Exhibit ES-1 presents a summary of the pore water quality analyses where exceedances are
expressed as multiplied factors of the Federal water quality criteria. Compared to current
technology, the projected number and magnitude of water quality criteria exceedances decreases
under the discharge option.
-------
ES-4
An additional method for assessing potential benthic impacts of certain metals is EPA's
proposed sediment guidelines for the protection of benthic organisms. These proposed
guidelines are based on an equilibrium partitioning (EqP) approach to determine guidelines based
on "numerical concentrations for individual chemicals that are applicable across the range of
sediments encountered in practice." The EqP sediment guidelines (ESG) for the six metals —
copper, cadmium, nickel, lead, silver, and zinc — account for the additive toxicity effects of these
metals. For this environmental assessment, the measured interstitial water [i.e., pore water]
concentrations of the metals are compared to water quality criteria final chronic values (FCVs).
The sum of the interstitial water concentration:FCV ratios for the six metals is calculated for
each of the model wells. The guideline is met if this sum is less than or equal to one.
In the Gulf of Mexico, all four model wells fail to meet the sediment guidelines using the
current technology, with concentration:FCV ratios ranging from 1.2 to 3.9 for the six-metal
composite (see Table ES-1). Under the discharge option, the development model wells meet the
guideline. While the exploratory model wells do not meet the guideline under the discharge
option, the projected pollutant pore water concentrations are 43 percent lower compared to those
projected for the current industry practice. For Cook Inlet, Alaska and offshore California, the
deep and shallow development model wells pass the guidelines using both the current technology
and the discharge option technology. EPA does not anticipate that exploratory wells will be
drilled in Cook Inlet and offshore California.
C. Human Health Effects
This portion of the environmental analysis presents the human health-related risks and risk
reductions (benefits) of current technology and the discharge and zero discharge regulatory
options. EPA based the health risks and benefits analysis on human exposure to carcinogenic
and noncarcinogenic contaminants through consumption of affected seafood; specifically,
recreationally-caught finfish and commercially-caught shrimp. EPA used seafood consumption
and lifetime exposure duration assumptions to estimate risks and benefits under the current
technology (11% retention) and discharge option (7% retention) scenarios for the three
geographic areas where the quantities of SBF-cuttings discharged will be affected by this rule.
The analysis is performed only for those contaminants for which bioconcentration factors, oral
reference doses (RfDs), or oral slope factors for carcinogenic risks have been established. Thus,
the analysis considers contaminants associated with the drilling fluid barite and with
contamination by formation (crude) oil, but does not consider the synthetic base compounds
themselves.
In order to derive the risks due to consumption of contaminated seafood, EPA first
determined the concentration of contaminants in finfish and shrimp tissues. Finfish tissue
contamination is affected by the level of contamination of water column, whereas, shrimp tissue
contamination is dependent on the level of contamination of sediment pore water.
-------
ES-5
Exhibit ES-1. Summary of Pore Water Quality Analyses (a, b)
[Exceedance Factor Over Federal Water Quality Criteria (c)]
Discharge
Region
Gulf of
Mexico
Cook Inlet,
Alaska
Offshore
California
Pollutant
Arsenic
Chromium
Mercury
Lead
Nickel
Metals
Composite (e)
Arsenic
Metals
Composite (e)
Arsenic
Metals
Composite (e)
Shallow Water
Development
Current
Tech-
nology
1.3
--
--
--
--
1.1
--
--
--
--
Discharge
Option
-(d)
--
--
--
--
--
--
--
--
--
Exploratory
Current
Tech-
nology
2.7
1.7
--
--
--
2.3
NA(f)
NA
NA
NA
Discharge
Option
--
--
--
--
--
1.3
NA
NA
NA
NA
Deep Water
Development
Current
Tech-
nology
1.9
1.3
--
--
--
1.7
NA
NA
1.2
1.1
Discharge
Option
1.1
--
--
--
--
--
NA
NA
--
--
Exploratory
Current
Tech-
nology
4.3
2.8
1.2
1.5
1.2
3.7
NA
NA
NA
NA
Discharge
Option
2.5
1.6
--
--
--
2.1
NA
NA
NA
NA
(a) Subsequent to finalization of the analyses contained in this document, EPA published revised water quality criteria (63
FR 68354, December 10, 1998). The following changes affect this Environmental Assessment water quality analyses
and will be reflected in the final rule: arsenic human health criterion is deleted; copper acute criterion is raised to 4.8
ug/1 and copper chronic criterion is raised to 3.1 ug/1; mercury chronic criterion is raised to 0.94 ug/1 and mercury
human health is reduced to 0.051 ug/1; and phenol human health criterion is deleted. Appendix B contains the
December 1998 criteria recommendations and an analysis of how the water quality assessment would change using
these revised criteria. In summary, with the new criteria, the arsenic and mercury exceedances are eliminated.
(b) There would be no exceedances for any pollutants with the zero discharge option.
(c) Values refer to the exceedance factor for the projected pollutant concentration compared to the Federal water quality
criteria; a value of 1.0, for example, indicates a pollutant concentration equal to the water quality criteria.
(d) — indicates that no exceedances are predicted.
(e) Metals composite includes cadmium, copper, lead, nickel, silver, and zinc.
(f) NA indicates that type of model well does not currently exist or is not projected for that geographic region.
Recreational Finfish Fisheries
Exposure of recreational finfish to drilling fluid contaminants occurs through the uptake of
dissolved pollutants found in the water column. Instead of using the water column pollutant
concentrations at the edge of the mixing zone (as for the water quality analyses), EPA calculates
an average water column concentration of each pollutant for the area within a 100-m radius of the
discharge. For the exposure of finfish within the 100-m mixing zone, the effective exposure
-------
ES-6
concentration is the exposure concentration adjusted by the volumetric proportion of the total
water column that contains the discharge plume. The effective exposure concentration of each
pollutant is multiplied by the exposure proportion and by a pollutant-specific bioconcentration
factor (BCF) to yield the tissue concentration of each pollutant in fmfish on a mg/kg basis.
The concentration of pollutants in fmfish tissue is used to calculate the risk of
noncarcinogenic and carcinogenic (arsenic only) risk from ingestion of recreationally-caught fish.
For this analysis, the 99th percentile intake rate of 177 g/day (uncooked basis) is used as the
exposure for high-end seafood consumers in the general adult population (SAIC, 1998). This
analysis is a worst case scenario because the seafood consumed is assumed to consist only of
contaminated fmfish.
For noncarcinogenic risk evaluation, the tissue pollutant concentration (mg/kg) is
multiplied by the consumption rate (mg/kg/day) for a 70 kg individual. This value is compared
to the oral reference dose (RfD) to determine the hazard quotient for each pollutant. If the hazard
quotient is less than or equal to one, toxic effects are considered unlikely to occur.
To calculate the carcinogenic risks, the slope factor as provided by the EPA Integrated Risk
Information System database (IRIS) is used to estimate the lifetime excess cancer risk that could
occur from ingestion of contaminated seafood. For this analysis, only arsenic has a slope factor
available for estimation of the lifetime excess cancer risk. For purposes of this assessment, EPA
considers a risk level of 1 x 10"6 to be acceptable.
Exhibit ES-2 presents a summary of the health risks from ingestion of recreationally-caught
fmfish from around SBF-cuttings discharges under current technology and the discharge option.
Although current practice in Cook Inlet, Alaska and offshore California is zero discharge of SBF-
cuttings, the current technology analysis is presented for comparison purposes. Numerically, the
hazard quotients and lifetime excess cancer risks decrease by 31 percent under the discharge
option as compared to current technology. However, in both current technology and discharge
option scenarios, the hazard quotients are several orders of magnitude less than 1, so toxic effects
are not predicted to occur. Also, the lifetime excess cancer risks for both current technology and
discharge option are less than 10"6 and are, therefore, considered by EPA acceptable for either of
these scenarios.
Commercial Shrimp Fisheries
EPA based projected shrimp tissue concentrations of pollutants from SBF discharges on
the uptake of pollutants from sediment pore water. The pore water pollutant concentrations are
based on the assumption of even distribution of the total annual SBF discharge over an area of
impact surrounding the model well.
-------
ES-7
Exhibit ES-2. Summary of Finfish Health Risks
Pollutant
Gulf of Mexico
Current
Technology
Discharge
Option
Cook Inlet, Alaska
Current
Technology
Discharge
Option
Offshore California
Current
Technology
Discharge
Option
99th Percentile Hazard Quotient (a, b)
Naphthalene
Fluorene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Chromium
Nickel
Selenium
Silver
Thallium
Zinc
3.85e-05
7.39e-07
3.60e-13
1.86e-06
7.90e-06
3.41e-06
1.25e-06
1.04e-05
3.27e-07
2.53e-07
1.68e-08
4.17e-04
3.09e-08
2.67e-05
5.12e-07
3.60e-13
1.29e-06
5.50e-06
2.37e-06
8.65e-07
7.23e-06
2.27e-07
1.75e-07
1.16e-08
2.89e-04
2.14e-08
3.91e-05
7.50e-07
3.66e-13
1.88e-06
8.02e-06
3.46e-06
1.27e-06
1.06e-05
3.32e-07
2.57e-07
1.70e-08
4.23e-04
3.13e-08
2.71e-05
5.20e-07
3.66e-13
1.31e-06
5.59e-06
2.40e-06
8.77e-07
7.33e-06
2.30e-07
1.78e-07
1.18e-08
2.93e-04
2.17e-08
3.72e-06
7.14e-08
3.48e-14
1.79e-07
7.63e-07
3.30e-07
1.21e-07
l.Ole-06
3.16e-08
2.45e-08
1.62e-09
4.03e-05
2.98e-09
2.58e-06
4.95e-07
3.48e-14
1.24e-07
5.32e-07
2.29e-07
8.35e-08
6.98e-07
2.19e-08
1.69e-08
1.12e-09
2.79e-05
2.07e-09
Lifetime Excess Cancer Risk (c, d)
Arsenic
30-yr exposure
70-yr exposure
2.41e-10
5.61e-10
1.67e-10
3.89e-10
2.44e-10
5.70e-10
1.69e-10
3.95e-10
2.32e-ll
5.42e-12
1.616-11
3.76e-12
(a)
(b)
(c)
(d)
Only pollutants for which there is an oral RfD are presented in this summary table.
None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
Only pollutants for which there is a slope factor are presented in this summary table.
The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
To calculate the noncarcinogenic and carcinogenic health risks for commercial shrimp, the
methodology is the same as that used for recreational fmfish. However, instead of calculating an
effective exposure concentration that describes the portion of the water affected within the
mixing zone, the exposure is adjusted by the amount of the total commercial shrimp catch
affected. This is estimated by prorating the total potential exposure (total catch) by the portion of
the total shrimp catch affected by the well type being analyzed. The shrimp catch is assumed to
occur evenly over the area occupied by the species harvested. Only shallow water model wells
are used in this assessment due to the limited shrimp harvesting that occurs in water depths
greater than 1,000 feet. Health risks for commercial shrimp were not performed for the Cook
Inlet, Alaska geographic area because shrimp are not harvested commercially in that area.
-------
ES-8
Exhibit ES-3 presents a summary of the health risks from ingestion of commercially-
caught shrimp. For both current technology and discharge option, the hazard quotients are
several orders of magnitude less than 1, so toxic effects are not predicted to occur under either
scenario. Also, all of the lifetime excess cancer risks for both current technology and discharge
option are less than 10"6 and are, therefore, acceptable under either scenario.
D. Toxicity
EPA has reviewed information concerning the determination of toxicity to the receiving
environment of SBFs and SBF base fluids. This information includes data generated for toxicity
requirements imposed on North Sea operators as well as experimental testing conducted by the
oil and gas industry in the United States. Because the synthetic base fluids are water insoluble
and the SBFs do not disperse in water as water-based drilling fluids (WBFs) do, but rather tend
to sink to the bottom with little dispersion, most research has focused on determining toxicity in
the sedimentary phase as opposed to the aqueous phase.
SBFs have routinely been tested using an aqueous phase test to measure toxicity of the
suspended particulate phase (SPP) (the SPP toxicity test) and found to have low toxicity.
However, recently presented data from an interlaboratory variability study indicates that the SPP
toxicity results are highly variable when applied to SBFs, with a coefficient of variation of 65.1
percent. Variability reportedly depended on such things as mixing times and the shape and size
of the SPP preparation containers.
North Sea testing protocols require monitoring the toxicity of fluids using a marine algae
(Skeletonema costatum\ a marine copepod (Arcartia tonsa), and a sediment worker (Corophium
volutator orAbra alba). The algae and copepod tests are performed in the aqueous phase,
whereas the sediment worker test uses a sedimentary phase. Again, because the SBFs are
hydrophobic and do not disperse or dissolve in the aqueous phase, the algae and copepod tests
are only considered appropriate for the water soluble fraction of the SBFs, while the sediment
worker test is considered appropriate for the insoluble fraction of the SBFs. As with the aqueous
phase algae and copepod tests, the SPP toxicity test mentioned above is only relevant to the water
soluble fraction of the SBFs.
Although there are data available on the toxicity of both SBFs and SBF base fluids from
the North Sea and United States, the information is insufficient to draw meaningful conclusions
other than broad generalizations. Also, little is known about the influence of organics in the
sediment on the toxicity of these fluids, be it a natural or a formulated sediment. However, with
the limited data, several assumption can be made.
(1) North Sea amphipods appear to be less sensitive to synthetic base fluids than those
amphipods currently used in US testing.
-------
ES-9
Exhibit ES-3. Summary of Shrimp Health Risks
Pollutant
Gulf of Mexico
Development
Current
Technology
Discharge
Option
Exploratory
Current
Technology
Discharge
Option
Offshore California
Current
Technology
Discharge
Option
99th Percentile Hazard Quotient (a)
Naphthalene
Fluorene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Chromium
Nickel
Selenium
Silver
Thallium
Zinc
4.71e-06
4.64e-08
5.28e-12
2.59e-06
1.10e-05
4.78e-06
1.74e-06
1.46e-05
4.57e-07
3.54e-07
2.34e-08
5.83e-04
4.32e-08
5.83e-05
5.70e-08
6.53e-12
3.19e-06
1.36e-05
5.91e-06
2.16e-06
1.80e-05
5.64e-07
4.35e-07
2.89e-08
7.21e-04
5.33e-08
5.44e-06
5.35e-08
6.12e-12
3.00e-06
1.28e-07
5.52e-06
2.02e-06
1.69e-05
5.28e-07
4.10e-07
2.72e-08
6.77e-04
4.99e-08
6.51e-06
6.43e-08
7.32e-12
3.60e-06
1.54e-05
6.62e-06
2.42e-06
2.02e-05
6.34e-07
4.92e-07
3.25e-08
8.09e-04
6.01e-08
2.08e-08
2.05e-10
2.34e-14
1.15e-08
4.89e-08
2.11e-08
7.70e-09
6.44e-08
2.02e-09
1.56e-09
1.04e-10
2.58e-06
1.91e-10
1.19e-08
1.17e-10
1.34e-14
6.54e-09
2.79e-08
1.21e-08
4.42e-09
3.68e-08
1.16e-09
8.92e-10
5.936-11
1.48e-06
1.09e-10
Lifetime Excess Cancer Risk (b)
Arsenic
30-yr exposure
70-yr exposure
3.36e-10
7.84e-10
4.16e-10
9.70e-10
3.89e-10
9.08e-10
4.67e-10
1.09e-10
1.49e-12
3.47e-12
8.52e-13
1.99e-12
(a) Only pollutants for which there is an oral RfD are presented in this summary table.
(b) Only pollutants for which there is a slope factor are presented in this summary table.
(2) When comparing SBFs and OBFs, base fluid toxicity appears to show greater
discriminatory power than does drilling fluid toxicity.
(3) Discriminatory power seems to be diminished with the use of formulated sediments.
(4) Mysid SPP testing does not seem to give meaningful results for SBFs.
Because data are limited, EPA and industry are continuing to gather information on
sediment toxicity through ongoing research. Industry is currently evaluating sediment test
methods, using formulated sediments and species sensitivities. EPA is beginning research on the
toxicity of synthetic base fluids and the factors that influence the toxicity of SBFs (as well as the
-------
ES-10
biodegradation and bioaccumulation of synthetic base fluids). The goal of this EPA research is
to restore discriminatory power to discern the differences in toxicity between diesel oil, mineral
oil, and synthetic base fluids. Because the current, examined amphipod test species are not
indicating sufficient discriminatory power, EPA may further consider using other test organisms,
such as polychaetes.
E. Bioaccumulation
EPA reviewed several studies on the bioaccumulation potential of synthetic base fluids.
The available information is scant, comprising only a few studies on octanol:water partition
coefficients (Pow) and two on tissue uptake in experimental exposures [only one of which derived
a bioconcentration factor (BCF)]. The Pow represents the ratio of a material present in the oil
phase, i.e., in octanol versus the water phase. The Pow generally increases as a molecule becomes
less polar (more hydrocarbon-like). The available information on the bioaccumulation potential
of synthetic base fluids covers only three types of synthetics: an ester (one studies), internal
olefins (IO; three studies), and poly alpha olefms (PAO; four studies). One study included a low
toxicity mineral oil (LTMO) for comparative purposes. This limitation with respect to the types
of synthetic base fluids tested is partially mitigated by the fact that these materials represent the
more common base fluids currently in use in drilling operations.
For PAOs, the log Pows reported were >10, 11.9, 14.9, 15.4, and 15.7 in the four studies
reviewed. The three studies of lOs that were reviewed reported log Pows of 8.57 and >9. The
ester was reported to have a log Pow of 1.69 in the one report in which it was tested. A log Pow of
15.4 was reported for an LTMO. The only BCF reported was calculated for lOs; a value of 5.4
was determined. In 30-day exposures of mud minnows (Fundulus grandis) to water equilibrated
with a PAO- or LTMO-coated cuttings, only the LTMO was reported to produce adverse effects
and tissue uptake/occurrence. Growth retardation was observed for the LTMO and LTMO was
observed at detectable levels in 50% of the muscle tissue samples examined (12 of 24) and most
(19 of 24) of the gut samples examined. The PAO was not found at detectable levels in any of the
muscle tissue samples and occurred in only one of twenty-four gut samples examined.
These limited data suggest that synthetic base fluids do not pose a serious bioaccumulation
potential. Despite this general conclusion, existing data cannot be considered sufficiently
extensive to be conclusive. This caution is specifically appropriate given the wide variety of
chemical characteristics resulting from marketing different formulations of synthetic fluids (i.e.,
carbon chain length or degree of unsaturation within a fluid type, or mixtures of different fluid
types). Additional data should be obtained both for the purpose of confirming what is known
about existing fluids and to ensure completeness and currency with new product development.
-------
ES-11
F. Biodegradation
EPA reviewed studies regarding the biodegradability of synthetic base fluids deposited on
offshore marine sediments. In addition, EPA compared the various methods used to predict SBF
biodegradation. Method variations include: calculation of biochemical oxygen demand in
inoculated freshwater aqueous media versus uninoculated seawater aqueous media;
determination of product (gases) evolved versus the concentration of synthetic base fluid
remaining at periodic test intervals; varying initial concentrations of test material; aqueous versus
sediment matrices; and within sediment matrices, layering versus mixed sediment protocols.
In the field, the mechanisms observed from the deposition of SBF contaminated drill
cuttings involve the initial smothering of the benthic community followed by organic enrichment
of the sediment due to adherent drilling fluids. Organic enrichment causes oxygen depletion due
to the biodegradation of the discharged synthetic base fluids. This biodegradation results in
predominantly anoxic conditions in the sediment, with limited aerobic degradation processes
occurring at the sediment: water column interface. Therefore, the biodegradation of deposited
drilling fluid will be an anaerobic process to a large degree. Standardized tests that utilize
aqueous media, while readily available and easily performed, may not adequately mimic the
environment in which the released synthetic base fluid is likely to be found and degraded. As a
result, alternative test methods have been developed that more closely simulate seabed
conditions.
The result of this review is that the current state of knowledge for these materials is as
follows:
(a) All synthetic fluids have high theoretical oxygen demands (ThODs) and are likely to
produce a substantial sediment oxygen demand when discharged in the amounts typical of
offshore drilling operations.
(b) Existing aqueous phase laboratory test protocols are incomparable and results are highly
variable. Sedimentary phase tests are less variable in their results, although experimental
differences between the "simulated seabed" and "solid phase" protocols have resulted in
variations between test results.
(c) There is disagreement among the scientific community as to whether slow or rapid
degradation of synthetic base fluids is preferable with respect to limiting environmental
damage and hastening recovery of benthic communities. Materials which biodegrade
quickly will deplete oxygen more rapidly than more slowly degrading materials. However,
rapid biodegradation also reduces the exposure period of aquatic organisms to materials
which may bioaccumulate or have toxic effects. EPA believes that rapid degradation is
preferable because seafloor recovery has been correlated with disappearance of the SBF
base fluid.
-------
ES-12
(d) Limited field data suggest these materials will be substantially degraded on a time scale of
one to a few years; however, the distribution and fate of these materials is not extensively
documented, especially as applicable to the Gulf of Mexico where only three field studies
have been conducted.
The limited data from field studies suggest that organic enrichment of the sediment is a
dominant impact of SBF-cuttings discharges. Biodegradability of these materials is therefore an
important factor in assessing their potential environmental fate and effects.
Each of the existing biodegradation test methods has advantages and disadvantages. The
seabed simulations better represent field conditions, but they are expensive and have limited
market availability. The standard aqueous test methods are not relevant to field conditions, but
are more rapid, more widely available, and less expensive. The solid phase test combines the
benefits of these two extremes: it mimics receiving water (sediment) conditions, is reproducible,
and can be made simplistic enough to perform at moderate expense.
G. Seabed Surveys
EPA reviewed and summarized seabed surveys conducted at sites where cuttings
contaminated with SBFs (SBF-cuttings) have been discharged. Since more surveys have been
performed and more detailed information has been collected at sites where WBFs (exclusively)
have been discharged, results from the WBF sites is also presented as a comparison. While the
technical performance of SBFs is comparable to that of OBFs, and EPA is projecting that SBFs
may be used as a replacement to OBFs more so than as a replacement of WBFs, as far as
environmental effects of discharge are concerned EPA believes that SBFs are more comparable
to WBFs. Also, WBFs are currently allowed for discharge in certain offshore and coastal areas,
while OBFs (and OBF-cuttings) are not. For these reasons, EPA sees it fitting to compare the
environmental effects of SBF-cuttings discharge with those of WBF and WBF-cuttings
discharge.
The reviewed seabed surveys measured either sediment or biologic effects from discharges
of either WBFs or SBFs. Specifically, indicators of drilling fluid impact of seabed sediments are
determined by measuring drilling fluid tracer concentrations (as either barium or SBF base fluid)
in the sediment at varying distances from the drill site in an attempt to determine fluid dispersion
and range of potential impact. Another class of impacts frequently measured are benthic
community effects. The purpose of these studies is to assess potential drilling fluid affects such
as increased metals and/or anoxia on biota.
-------
ES-13
There is very little information upon which to base any broad conclusions about the
potential extent of impacts from the discharge of SBF-cuttings. It appears that biological impacts
may range from as little as 50 m to as much as 500 m shortly after discharges cease to as much as
200 m a year later. Ester SBFs appear to be more readily biodegraded in North Sea studies than
an ether SBF; the Gulf of Mexico study suggests PAOs also are less biodegradable than esters.
Also, although esters appear to be readily biodegraded, one study indicates the persistence of
uncharacterized "minor" impacts on benthos after synthetic-based fluid levels have fallen to
reference levels. These limited data, however, are not entirely adequate as a basis for any reliable
projections concerning the potential nature and extent of impacts from discharges of SBFs.
However, the reported adverse benthic community impacts are expected, given the basic SBF
and marine sediment chemistry, the level of nutrient enrichment from these materials, and the
ensuing development of benthic anoxia. The extent and duration of these impacts are much more
speculative. Severe effects seem likely within 200 m of the discharge; impacts as far as 500 m
have been demonstrated. The initiation of benthic recovery seems likely within a year, although
it also seems unlikely that it will be complete within one year. And the relative impacts of the
various types of SBFs is speculative given the limited marine sediment applicability of available
laboratory methods for assessing toxicity and biodegradability and the paucity of field data for
laboratory versus field correlations.
-------
1-1
1. INTRODUCTION
This document presents the analyses and results of the environmental assessment for the
proposed rule for the wastestream of synthetic-based drilling fluids (SBFs) and other non-
aqueous drilling fluids, and cuttings contaminated with these drilling fluids. The environmental
assessment consists of an evaluation of the ecological and indirect human health impacts for each
proposed regulatory option with respect to discharges to water. This document describes the
environmental characteristics of SBF drilling wastes (e.g., toxicity, bioaccumulation,
biodegradation), the types of anticipated impacts, and the pollutant modeling results for water
column concentrations, pore water concentrations, and human health effects via consumption of
affected seafood. This document does not consider the potential non-water quality
environmental effects associated with the proposed rule.
Since about 1990, the oil and gas extraction industry has developed many new oleaginous
(oil-like) base materials from which to formulate high performance drilling fluids. A general
class of these are called "synthetic" materials. This class of substances include vegetable esters,
poly alpha olefms, internal olefms, linear alpha olefins, synthetic paraffins, ethers, linear alkyl
benzenes, and others. Other, nonsynthetic oleaginous materials have also been developed for this
purpose, such as the enhanced mineral oils and non-synthetic paraffins. Industry developed these
synthetic and non-synthetic oleaginous materials as the base fluid to provide the drilling
performance characteristics of traditional oil-based fluids (OBFs) based on diesel and mineral oil,
but with lower environmental impact and greater worker safety. These environmental and safely
characteristics have been achieved through lower toxicity, elimination of polynuclear aromatic
hydrocarbons (PAHs), faster biodegradability, lower bioaccumulation potential, and, in some
drilling situations, less drilling waste volume. In this document, the synthetic or other new
oleaginous base fluids will be referred to collectively as synthetic base fluids. The drilling fluids
formulated from them will be referred to collectively as SBFs.
As SBFs came into commercial use, EPA determined that the current drilling discharge
monitoring methods, which were developed to control the discharge of water-based fluids
(WBFs), did not appropriately control the discharge of these new drilling fluids. Because WBFs
disperse in water, oil contamination of WBFs with formation oil or other sources can be
measured by the static sheen test. Many soluble or water-accommodated toxic components of
the WBFs will disperse in the aqueous phase and be detected by the suspended particulate phase
(SPP) toxicity test. With SBFs, which are highly hydrophobic and do not disperse in water but
instead sink as a mass, formation oil contamination has been shown to be less detectable by the
-------
1-2
static sheen test. Similarly, the potential toxicity of the discharge to the benthos is not apparent
in the current SPP toxicity test.
EPA has, therefore, sought to identify methods to control the discharge of cuttings
associated with SBFs (SBF-cuttings) in a way that reflects the appropriate level of technology.
One way to do this is through stock limitations on the base fluids from which the drilling fluids
are formulated. This would ensure that the substitution of synthetic and other oleaginous base
fluids for traditional mineral and diesel oils reflects the appropriate level of technology. In other
words, EPA wants to ensure that only the SBFs formulated from the "best" base fluids are
allowed for discharge. Parameters that distinguish the various base fluids are the polynuclear
aromatic hydrocarbon (PAH) content, sediment toxicity, rate of biodegradation, and potential for
bioaccumulation.
EPA also thinks that the SBF-cuttings should be controlled with other limitations, such as a
limitation on the toxicity of the SBF at the point of discharge and a limitation on the mass or
concentration of SBFs discharged with the drill cuttings. The latter type of limitation would take
advantage of the solids separation efficiencies achievable with SBFs, and consequently minimize
the discharge of organic and toxic components.
In addition to the discharge option described above, EPA is also considering a zero
discharge option for SBF-cuttings. EPA would select zero discharge as the preferred option if
the controls in the discharge option proved to be inadequate or inappropriate.
EPA has determined the water quality and human health impacts of each of the two
regulatory options (i.e., discharge and zero discharge) based on changes in the discharge of SBF
wastes, and on the number of wells projected to use SBFs. Under the discharge option, wells
drilled using SBFs will be allowed to discharge SBF-cuttings. Due to the proposed limitations,
less SBF would be retained on the cuttings and so less SBF would be discharged per well than is
currently practiced in the Gulf of Mexico. In addition, under the discharge option, EPA will
control the toxicity, PAH content, and biodegradation rate of the base fluids used in SBFs. For
wells currently using OBFs for drilling, EPA projects that under the discharge option, a portion
of these wells will convert to SBF usage and will discharge SBF-cuttings. These wells comprise
a fraction of the OBF wells drilled in the Gulf of Mexico and all of the OBF wells drilled in
offshore California and Cook Inlet, Alaska.
The effect of the zero discharge option would be to eliminate the discharge of SBF-cuttings
into ambient waters by those wells currently drilled with SBFs. However, EPA believes another
-------
1-3
effect of zero discharge would be that many of the wells currently using SBFs would convert to
OBFs.
This environmental assessment presents background information and several types of
characterizations and assessments concerning the discharge of SBFs and SBF-cuttings, including:
• A description of the regulatory options considered for the proposed rule (Chapter 2).
• A characterization of the industry, including the geographic areas and the population
affected by the proposed rule (Chapter 3).
Wastestream characterizations in terms of SBFs and SBF-cuttings (Chapter 3).
Characterization of the affected environment, including the receiving water and fisheries
(Chapter 3).
• Water quality compliance assessments for SBF-cuttings discharges to receiving waters and
comparison of receiving water pollutant concentrations (water column and interstitial
(pore) water) projected from surface water dispersion modeling to Federal numeric water
quality standards (Chapter 4).
• A carcinogenic and non-carcinogenic risk assessment for SBF-cuttings for high-rate
seafood consumption, based on seafood contamination levels projected from modeling
(Chapter 5).
A summary and comparison of the aquatic toxicity test results conducted to date on SBFs
(Chapter 6).
• A summary and comparison of bioaccumulation study results conducted to date on SBFs
(Chapter 7).
A summary and comparison of biodegradation study results conducted to date on SBFs
(Chapter 8).
• A summary and comparison of seabed survey results conducted to date on SBF discharges
to assess benthic impacts (Chapter 9).
The pollutant concentrations in water and seafood tissue are based solely on analysis of
discharges from this one particular wastestream under different regulatory options. That is, the
analyses do not consider background pollutant concentrations or pollutant loadings from other
potential discharges.
-------
2-1
2. DESCRIPTION OF REGULATORY OPTIONS
This environmental assessment determines impacts for the discharge of wastes associated
with synthetic-based drilling fluids (SBFs) under current industry practice and the two regulatory
options considered by EPA for the SBF rule: a discharge option and a zero discharge option.
The discharge option controls the stock base fluid through limitations on PAH content,
sediment toxicity, and biodegradation rate. At the point of discharge, the discharge option
controls sheen, formation oil content, and retention of SBF on the cuttings. The discharge
option also maintains current requirements of stock limitations on barite of mercury and
cadmium, and the diesel oil discharge prohibition.
While discharge of SBF-cuttings would be allowed under the discharge option, discharge
of SBFs not associated with drill cuttings would not be allowed. Since zero discharge of neat
SBFs is current industry practice due to the value of the SBFs recovered, this option has no
incremental environmental impact. For this portion of the wastestream, therefore, an
environmental assessment was not conducted.
Under the zero discharge option, neat SBFs (not associated with drill cuttings) as well as
SBF-cuttings would be prohibited from discharge. Because the zero discharge option results in
the absence of discharged pollutants, the environmental assessment analyses did not require
calculations to demonstrate zero environmental impacts.
EPA determined that the only major effect that the discharge option would have on the
characterization of the SBF-cuttings currently discharged would be to reduce the retention of the
SBF on the cuttings from 11% base fluid to 7% base fluid. This means that for the purpose of
this environmental assessment, base fluid selection, formation oil contaminant level, and sheen
forming characteristics would not be materially affected in moving from current practice to the
discharge option.
Current industry practice for managing and treating SBF-cuttings before discharge is to
send the cuttings through solids separation equipment that separates the drill cuttings from the
drilling fluid. The drilling fluid is recovered and reused. The drill cuttings are considered waste
and are discharged under permit requirements. The solids separation equipment consist of
primary and secondary shale shakers and occasionally a centrifuge. Based on industry data, the
efficiency of current solids separation equipment results in a long term average of 11% (by
-------
2-2
weight) retention of SBF base fluid on cuttings (EPA, 1999). "Retention" is defined as the
percentage of base fluid remaining on the wet cuttings (on a weight/weight basis). It is
determined using an industry standard test in which the cuttings sample is heated, the liquid is
separated from the solids, and the weight percent liquid in the original sample is calculated.
The technology basis for the discharge option is an add-on, vibrating centrifuge to current
solids separation equipment. Based on performance data, the long term average retention for the
add-on technology is 7% by weight (EPA, 1999). The 7% retention value is used as the basis for
determining the amount of SBF discharged on cuttings in the discharge option, and consequently,
the amount of pollutants discharged.
The different SBF retention values, 11% for current technology and 7% for the discharge
option, represent different amounts of SBF discharged into the receiving water. For the water
quality analyses (Chapter 4) and the human health impact assessments (Chapter 5), the impacts
under the discharge option (7% retention) and under current technology (11% retention) were
determined.
Also, EPA projects that the discharge option would encourage operators to convert wells
currently drilled with oil-based drilling fluid (OBF) to SBF. Thus, EPA projects that in the Gulf
of Mexico, while 113 wells annually are currently projected to drill with SBF, after the rule an
additional 23 wells, for a total of 136 would drill with SBF. Therefore, the analyses of this
environmental assessment assume that in the Gulf of Mexico, the current practice is 113 wells
discharging at 11% base fluid retention on cuttings and the discharge option would give 136
wells drilled annually and discharging cuttings at 7% retention.
In offshore California and Cook Inlet, Alaska, no SBF wells are currently drilled. EPA
projects that the 12 OBF wells in California and the one OBF well in Cook Inlet will convert to
SBF as a result of this rule. Therefore, in the discharge option, 12 SBF wells would be drilled
annually in California, one SBF well would be drilled annually in Cook Inlet and these wells
would discharge the SBF-cuttings at 7% base fluid retention. Even though these wells currently
use OBF and do not discharge, in order to compare with current technology, this environmental
assessment also calculates the impacts that would occur if these California and Cook Inlet wells
used SBF and discharged at 11% retention.
Current regulations establish the geographic areas where drilling wastes may be
discharged: offshore subcategory waters beyond 3 miles from the shoreline and, in Alaska,
offshore waters with no 3-mile restriction. The SBF effluent guidelines would be applicable only
where drilling wastes are currently allowed for discharge. The only coastal subcategory waters
-------
2-3
where drilling wastes may be discharged is in Cook Inlet, Alaska. In total, there are three areas
where current guidelines allow drilling wastes to be discharged and drilling is active: offshore
Gulf of Mexico, offshore California, and Cook Inlet, Alaska. Because these are the only
geographic areas where EPA projects pollutant loadings to change as a result of the proposed
rule, they are the only areas considered in the environmental assessment.
-------
3-1
3. CHARACTERIZATION
3.1 Industry Characterization
The geographic areas where drilling wastes are allowed to be discharged are: the offshore
subcategory waters of the Atlantic, Gulf of Mexico, and Pacific coasts beyond 3 miles from
shore; all of the offshore subcategory waters of Alaska, which has no 3 mile discharge restriction;
and the coastal subcategory waters of Cook Inlet, Alaska. Within these discharge areas, drilling
is currently active in three places: (i) the Gulf of Mexico (GOM), (ii) offshore southern
California; and (iii) Cook Inlet, Alaska. Offshore subcategory waters of Alaska has active
drilling and effluent guidelines allows discharge. However, drilling wastes are not currently
discharged in the Alaska offshore waters.
Among these three areas, the vast majority of drilling activity occurs in the GOM, where
1,302 wells were drilled in 1997. This activity compares to 28 wells drilled in California and 7
wells drilled in Cook Inlet in 1997. In the GOM, over the last few years, there has been a high
growth in the number of wells drilled in the deepwater, defined by the Minerals Management
Service (MMS) as water greater than 1,000 feet deep. For example, in 1995, 84 wells were
drilled in the deepwater, comprising 8.6 percent of all GOM wells drilled that year. By 1997,
that number increased to 173 wells drilled and comprised over 13 percent of all GOM wells
drilled. This increased activity in deepwater increases the usefulness of SBFs. Operators drilling
in deepwater cite the potential for riser disconnect in floating drill ships, which favors SBF over
OBF; higher daily drilling cost that more easily justifies use of more expensive SBFs over
WBFs; and the greater distance to barge drilling wastes that may not be discharged (i.e., OBFs).
EPA has adopted the MMS categorization of drilling wells according to type of drilling
operation, i.e., exploratory or development, and water depth. Deep water wells are wells that are
drilled in water depths greater than 1,000 feet whereas shallow water wells are drilled in water
less than 1,000 feet. Using information gathered from industry, EPA projected the number of
wells drilled annually using SBFs, WBFs, and OBFs (EPA, 1999). Table 3-1 presents a
summary of the wells drilled with OBFs and SBFs as used in the analyses for the environmental
assessment. For the water quality and human health impact analyses, EPA projected that under
the discharge option, certain wells currently using OBFs would switch to SBF usage (EPA,
1999). In the Gulf of Mexico, EPA projected that 20% of the wells drilled with OBF, all of
which are located in shallow water, would convert to SBF. In Cook Inlet, Alaska and offshore
California, EPA projected that all OBF wells would convert to SBF.
-------
3-2
Exhibit 3-1. Estimated Number of Wells Drilled Annually By Drilling Fluid
Type of Well
Shallow Water
(<1,000 ft)
Develop.
Explor.
Deep Water
(>1,000 ft)
Develop.
Explor.
Total
Wells
Gulf of Mexico
Baseline All Wells (a)
Baseline SBF Wells
Discharge Option SBF Wells
Zero Discharge Option SBF Wells
645
13
28 (b)
0
358
7
15
0
48
36
36(c)
36
76
57
57
57
1,127
113
136
93
Offshore California (d)
Baseline All Wells
Baseline OBF Wells
Discharge Option SBF Wells
11
1
1
0
0
0
15
11
11
0
0
0
26
12
12
Coastal Cook Inlet, Alaska (d)
Baseline All Wells
Baseline OBF Wells
Discharge Option SBF Wells
7
1
1
1
0
0
0
0
0
0
0
0
8
1
1
(a) While this table lists total number of wells, the only wells included in the analysis are those affected by this
rule: SBF wells or wells converting from OBF to SBF in discharge option or converting from SBF to OBF in
zero discharge option.
(b) EPA assumes that 95 percent of GOM shallow water development wells of this analysis are existing sources,
and 5 percent are new sources (equals one new source well).
(c) EPA assumes that 50 percent of GOM deep water development wells of this analysis are existing sources, and
50 percent are new sources (equals 18 new source wells).
(d) EPA assumes all offshore California and Cook Inlet, Alaska, wells are existing sources, and in discharge option
all OBF wells convert to SBF wells.
Source: EPA, 1999
3.2 Wastestream Characterization
The American Petroleum Institute (API) provided EPA with characteristic well data in
terms of well diameters and well section depths for model wells. From this, EPA calculated the
volumes of waste generated (EPA, 1999). As in the MMS data, API information distinguishes
wells into four categories: shallow water development, shallow water exploratory, deep water
development, and deep water exploratory.
-------
3-3
Drill cuttings are produced continuously at the bottom of the hole at a rate proportionate to
the advancement of the drill bit. These drill cuttings are carried to the surface by the drilling
fluid, where the cuttings are separated from the drilling fluid by the solids control system. The
drilling fluid is then sent back down hole, provided it still has characteristics to meet technical
requirements. Various sizes of drill cuttings are separated by the solids separations equipment. It
is necessary to remove both the fines (small sized cuttings) and the large sand- and gravel-sized
cuttings from the drilling fluid stream to maintain the required flow properties.
Because of cost, SBFs, used or unused, are considered a valuable commodity by the
industry and not a waste. It is industry practice to continuously reuse the SBF while drilling a
well interval, and at the end of the well, to ship the remaining SBF back to shore for
refurbishment and reuse. Compared to WBFs, SBFs are relatively easy to separate from the drill
cuttings because the drill cuttings do not disperse in the drilling fluid to the same extent. With
WBF, due to dispersion of the drill cuttings, drilling fluid components often need to be added to
maintain the required drilling fluid properties. These additions are often in excess of what the
drilling system can accommodate. The excess "dilution volume" of WBF is discharged. This
excess dilution volume does not occur with SBF. For these reasons, SBF is only discharged as a
contaminant of the drill cuttings wastestream. It is not discharged as neat drilling fluid (drilling
fluid not associated with cuttings).
The top of the well is normally drilled with a WBF. As the well becomes deeper, the
performance requirements of the drilling fluid increase, and the operator may, at some point,
decide that the drilling fluid system should be changed to either a traditional OBF using diesel oil
or mineral oil, or an SBF. The system, including the drill string and the solids separation
equipment, must be changed entirely from the WBF to the SBF (or OBF) system, because the
two drilling fluid systems do not function as a blended system. Thus, the entire system is either a
water dispersible drilling fluid or a water non-dispersible drilling fluid (such as an SBF). The
decision to change the system from a WBF water dispersible system to an OBF or SBF water
non-dispersible system depends on many factors including:
• the operational considerations, i.e. rig type (risk of riser disconnects with
floating drilling rigs), rig equipment, distance from support facilities,
• the relative drilling performance of one type fluid compared to another, e.g., rate of
penetration, well angle, hole size/casing program options, horizontal deviation,
• the presence of geologic conditions that favor a particular fluid type or performance
characteristic, e.g., formation stability/sensitivity, formation pore pressure vs.
fracture gradient, potential for gas hydrate formation,
• drilling fluid cost - base cost plus daily operating cost,
-------
3-4
• drilling operation cost - rig cost plus logistic and operation support, and
• drilling waste disposal cost.
Industry has commented that while the right combination of factors that favor the use of SBF can
occur in any area, they most frequently occur with "deep water" operations. This is due to the
fact that these operations are higher cost and can therefore better justify the higher initial cost of
SBF use.
The volume of cuttings generated while drilling the SBF intervals of a well depends on the
type of well (development or production) and the water depth. According to analyses of the
model wells provided by industry representatives, wells drilled in less than 1,000 feet of water
are estimated to generate 565 barrels of cuttings for a development well and 1,184 barrels of
cuttings for an exploratory well. Wells drilled in water greater than 1,000 feet deep are estimated
to generate 855 barrels of cuttings for a development well, and 1,901 cuttings for an exploratory
well (see Exhibit 3-2). These values assume 7.5 percent washout, based on the rule of thumb
reported by industry representatives of 5 to 10 percent washout when drilling with SBF.
Washout is caving in or stuffing off of the well bore. Washout, therefore, increases hole volume
and increases the amount of cuttings generated when drilling a well. Assuming no washout, the
values above become, respectively, 526, 1,101, 795, and 1,768, barrels of dry cuttings.
The drill cuttings range in size from large particles on the order of a centimeter in size to
small particles a fraction of a millimeter in size, called fines. As the drilling fluid returns from
downhole laden with drill cuttings, it normally is first passed through primary shale shakers
which remove the largest cuttings, ranging in size of approximately 1 to 5 millimeters. The
drilling fluid may then be passed over secondary shale shakers to remove smaller drill cuttings.
Finally, a portion or all of the drilling fluid may be passed through a centrifuge or other shale
shaker with a very fine mesh screen, for the purpose of removing the fines. It is important to
remove fines from the drilling fluid in order to maintain the desired flow properties of the active
drilling fluid system. Thus, the cuttings wastestream usually consists of larger cuttings from a
primary shale shaker, smaller cuttings from a secondary shale shaker, and fines from a fine mesh
shaker or centrifuge.
Before being discharged, the larger cuttings are sometimes sent through an additional
separation device in order to recover additional drilling fluid.
The recovery of SBF from the cuttings serves two purposes. The first is to deliver drilling
fluid for reintroduction to the active drilling fluid system and the second is to minimize the
discharge of SBF. The recovery of drilling fluid from the cuttings is a conflicting concern,
-------
3-5
Exhibit 3-2. Volume of SBF-Cuttings Generated Per Model Well
Parameter
Calculated SBF Interval Volume (bbls)
SBF Interval Volume Plus
7.5% Washout (bbls)
Amount of Dry Cuttings Generated Per
Interval Volume (Ibs)
Shallow Water
(<1,000 ft)
Development
526
565
514,150
Exploratory
1,101
1,184
1,077,440
Deep Water
(> 1,000 ft)
Development
795
855
778,050
Exploratory
1,768
1,901
1,729,910
Source: EPA, 1999
because as more aggressive methods are used to recover the drilling fluid from the cuttings, the
cuttings tend to break down and become fines. The fines are more difficult to separate from the
drilling fluid (an adverse affect for pollution control purposes), but in addition they deteriorate
the properties of the drilling fluid. Increased recovery from cuttings is more of a problem for
WBF than SBF because in WBFs the cuttings disperse more and spoil the drilling fluid
properties. Therefore, compared to WBF, more aggressive methods of recovering SBF from the
cuttings wastestream are practical. These more aggressive methods may be justified for cuttings
associated with SBF so as to reduce the discharge of SBF. This, consequently, will reduce the
quantity of toxic organic and metallic components of the drilling fluid discharged.
Drill cuttings are typically discharged continuously during drilling, as they are separated
from the drilling fluid in the solids separation equipment. The drill cuttings will also carry a
residual amount of adherent drilling fluid. Total suspended solids (TSS) makes up the bulk of
the pollutant loadings, and is comprised of two components: the drill cuttings themselves, and
the solids in the adhered drilling fluid (see Exhibit 3-3). The drill cuttings are primarily small
bits of stone, clay, shale, and sand. The source of the solids in the drilling fluid is primarily the
barite weighting agent, and clays that are added to modify the viscosity. Because the quantity of
TSS is so high and consists of mainly large particles that settle quickly, discharge of SBF drill
cuttings can cause benthic smothering and/or sediment grain size alteration resulting in potential
damage to invertebrate populations and benthic community structure.
Additionally, environmental impacts can be caused by toxic, conventional, and
nonconventional pollutants adhering to the solids. The adhered SBF drilling fluid is mainly
composed, on a volumetric basis, of the synthetic material, or more broadly speaking, oleaginous
-------
3-6
Exhibit 3-3. Model Well Characteristics
Parameter
Amount of Cuttings (Ibs)
(= TSS associated with drill cuttings)
Amount of Solids as Barite (Ibs)
(=TSS associated with drilling fluid)
@11% retention
@7% retention
Amount of Synthetic Base Fluid
Associated with Adhering Drilling Fluid
(Ibs) @11% retention
@7% retention
Amount of Crude at 0.2% (vol.)
Contamination (Ibs)
@11% retention
@7% retention
Shallow Water
(<1,000 ft)
Development
514,150
51,818
29,661
73,834
42,287
228
131
Exploratory
1,077,440
108,588
62,158
154,724
88,616
478
274
Deep Water
(> 1,000 ft)
Development
778,050
78,414
44,886
111,730
63,992
345
198
Exploratory
1,729,910
174,346
99,799
248,420
142,279
767
440
Source: EPA, 1999
material. The oleaginous material may be toxic or bioaccumulate, and it may contain priority
pollutants such as polynuclear aromatic hydrocarbons (PAHs). This oleaginous material may
cause hypoxia (reduction in oxygen) or anoxia in the immediate sediment, depending on bottom
currents, temperature, and rate of biodegradation. Oleaginous materials which biodegrade
quickly will deplete oxygen more rapidly than more slowly degrading materials. EPA, however,
believes that rapid biodegradation is environmentally preferable to persistence despite the
increased risk of anoxia which accompanies fast biodegradation. This is because recolonization
of the area impacted by the discharge of SBF-cuttings or OBF-cuttings has been correlated with
the disappearance of the base fluid in the sediment, and does not seem to be correlated with
anoxic effects that may result while the base fluid is disappearing. In studies conducted in the
North Sea, base fluids that biodegrade faster have been found to disappear more quickly, and
recolonization at these sites has been more rapid (Daan et al., 1996 and Schaanning, 1995).
As a component of the drilling fluid, the barite weighting agent is also discharged as a
contaminant of the drill cuttings. Barite is a mineral principally composed of barium sulfate, and
it is known to generally have trace contaminants of several toxic heavy metals such as mercury,
cadmium, arsenic, chromium, copper, lead, nickel, and zinc. EPA developed a profile of metals
concentrations in drilling fluids formulated with barite as part of the Offshore Effluent
-------
3-7
Limitations Guidelines rulemaking effort. As a result of the Offshore Effluent Limitations
Guidelines, stock barite must meet the maximum limitations of cadmium of 3 mg/1 and for
mercury of 1 mg/1. Exhibit 3-4 lists the concentrations of the pollutants associated with barite.
Formation oil is another contaminant of drilling fluids. Together with the synthetic oil,
formation oil contributes to the total oil concentration found in drilling fluids. EPA estimates
that a model SBF wastestream will contain 0.2% by volume formation oil (EPA, 1999). EPA
obtained the concentrations for both priority and non-conventional organic pollutants from
analytical data presented in the Offshore Subcategory Oil and Gas Development Document for
Gulf of Mexico diesel (EPA, 1993). Thus, EPA used diesel oil as an estimate for formation oil in
terms of pollutant content. Exhibit 3-5 lists the concentrations of organic pollutants found in
SBF drilling fluid contaminated with formation oil.
Exhibit 3-4. Heavy Metal Concentrations in Barite
Pollutant
Average Concentration of
Pollutants in Barite (mg/kg)
Reference
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
1.1
0.1
5.7
7.1
0.7
240.0
18.7
35.1
13.5
1.1
0.7
1.2
200.5
Offshore Development
Document, Table XI-6
(EPA, 1993)
Non-Conventional Metals
Aluminum
Barium
Iron
Tin
Titanium
9,069.9
120,000
15,344.3
14.6
87.5
Offshore Development
Document, Table IX-6,
except barium, which was
estimated (EPA, 1993)
-------
3-8
Exhibit 3-5. Formation Oil Characteristics
Pollutant
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol (,ug/g)
Non-Conventional Pollutants
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols C"g/g)
Total biphenyls
Total dibenzothiophenes C"g/g)
Average Concentration
of Pollutants in SBF Contaminated
with Formation Oil
mg pollutant/
ml formation oil
1.43
0.78
1.85
6
8.05
75.68
9.11
11.51
52.9
14.96
760
Ibs/bbl of SBF
(a)
0.0010052
0.0005483
0.0013004
7.22E-08
0.0056587
0.0531987
0.0064038
0.0080909
0.0000006
0.0105160
0.0000092
Reference
Ibs/bbl pollutant cone.
calculated from Offshore
Dev. Doc., Table VII-9
(EPA, 1993)
(a)
Assumes 0.2% contamination from formation oil using diesel as an estimate of pollutant content.
3.3 Receiving Water Characterization
3.3.1 Gulf of Mexico
The Gulf of Mexico is a semi-enclosed sea that can be subdivided into four physiographic
regions: the continental shelf, the continental slope and associated canyons, the Yucatan Strait,
and the Straits of Florida. Physical oceanography is dominated by the clockwise flow of the
Loop Current that enters the Gulf through the Yucatan Strait and exits through the Straits of
Florida. The average position of the northern part of the Loop Current is close to 26 °N and the
mean eastern side of the Loop Current is west of the 2000 m isobath offshore Florida
(MMS,1989). The most northerly position occurs on the slope just south of Mobile, Alabama.
The Loop sheds large eddies (diameters of 300 to 400 km, averaging 234 km) that last for periods
ranging from 4 to 12 months (MMS, 1989; 1991). The vertical extent of these eddies ranges to
over 1,000m.
Surface temperatures are nearly isothermal during summer (29°-30°C), but show strong,
horizontal temperature gradients in winter ranging from 25 °C at the core of the Loop current to
14-15°C over the northern coastal areas. Salinities range from a low of 20 ppt during periods of
high freshwater inflow from the Mississippi River to a high of 29-32 ppt during periods of low
-------
3-9
freshwater inflow. The thermocline also migrates due to seasonal influences. The thermocline
depth is approximately 45 m during summer and ranges from between 30 m to 60 m during
winter.
Current speeds reported at a depth of 100 m from a mooring buoy located at the 1000 m
isobath off Louisiana averaged 13.4 cm/s for a period of November to September (MMS, 1989).
MMS (1988) reports an average current speed of 17.2 cm/s for December to April at a depth of
35 m in about 400 m water depth near Green Canyon off Louisiana. MMS (1988) also reports an
average current speed of 13.6 cm/s at 55 m depth in 100 m water depth (near West Flower
Garden Bank, south of Louisiana/Texas border) and an average of 19.8 cm/s at 63 m depth in 280
m water depth (East Breaks vicinity, south of Galveston, Texas).
Most drilling activity in the Gulf of Mexico occurs in the Central and Western planning
areas for MMS, generally offshore Louisiana and Texas.
3.3.2 Cook Inlet, Alaska
Cook Inlet is located on the northwest edge of the Gulf of Alaska in southcentral Alaska. It
is a large tidal estuary that is approximately 330 km long increasing in width from 36 km in the
north to 83 km in the south. The upper inlet has water depths of 30 m to 60 m and has extensive
tidal marshes and mud flats along the western and northern margins. At the East and West
Forelands, where the upper inlet is divided from the lower inlet, water depths increase to over
130 m in deeper channels. In Lower Cook Inlet water depths range from 30 m to 40 m below the
forelands to over 180 m at the entrance to the inlet.
The circulation pattern of Lower Cook Inlet is a complex pattern influenced by large tidal
ranges, bathymetry, surface wind patterns, Coriolis effect, water density structure, and shoreline
configuration. Surface circulation in the lower inlet appears to follow a generally counter-
clockwise pattern near the mouth of the inlet as clear oceanic waters are met by more turbid
water flowing south through the inlet (Dames & Moore, 1978).
Cook Inlet currents are dominated by tidal currents and large-scale, local or regional
meterological events (EPA Region 10, 1984). Tidal currents range from 10 to 50 cm/sec. Above
the tidal currents, the Kenai Current and western surface outflows affect Cook Inlet circulation.
Houghton et al., 1981 measured flood tides ranging from 77 cm/sec to 51 cm/sec for depths
ranging from 14 m to 52 m and ebb tide ranging from 103 cm/sec to 41 cm/sec for the same
depths at one point in Cook Inlet.
-------
3-10
Salinity in Cook Inlet varies seasonally due to variations in fresh water inflow. During
summer (May through September) river discharges decrease the salinity of the upper Inlet.
During winter, intrusion by more saline oceanic waters increase salinity throughout the Inlet. At
the mouth of the Inlet salinity value remain nearly constant at 32 ppt. As a result of circulation
patterns, salinity on the eastern side of Lower Cook Inlet tends to be higher than the western side.
Cook Inlet is characterized by large quantities of glacial sediments washed into the upper
inlet from seven major glacier-fed rivers. Sediment inflow from glacial sources is seasonal with
larger amounts of glacially-derived sediment occurring in summer months. In upper Cook Inlet,
clay- and silt-sized particles are kept in suspension by tidal currents. The bulk of this fine
sediment is transported down the west side of the inlet and deposited in the Aleutian Trench
beyond Kodiak Island. Extreme ranges of sediments vary from 1 to 2 mg/1 at the mouth of Cook
Inlet to over 2,000 mg/1 in Knit Arm (Dames & Moore, 1978).
3.3.3 Offshore California
The Southern California Bight is the area of the California coastline from Point Conception
in the north to San Diego in the south. Currently, it is the only area with oil and gas activity in
the offshore California discharge region. The area has three principle features: (i) a narrow
continental shelf ranging in width between 3 km and 10 km; (ii) distinct basins with depths to 1
km; and (iii) a number of islands.
Circulation on the shelf of southern California is not well defined (MMS, 1991). The
offshore flow is generally a counter-clockwise flow from the shelf and slope area north of Point
Conception past the channel islands and then eastward where it intersects the shelf at a point not
precisely determined.
The major surface currents offshore California are the California Current (mean speed
about 15 cm/sec) that flows generally southward and affects areas further offshore and the
Davidson Current (speeds up to 15-30 cm/sec) that flows northward closer to the shore. The
Davidson Current mainly occurs in areas where oil and gas leases occur offshore California
(MMS, 1985).
-------
3-11
3.4 Recreational and Commercial Fisheries
3.4.1 Gulf of Mexico
Recreational Finftsh
In the Gulf of Mexico, 1,818 people participated in 16,319 recreational fishing trips
(excluding Texas). In Texas 266,500 man-hours of sport-boat fishing were reported for the
Exclusive Economic Zone in 1991 (NMFS, 1997). Data from the National Marine Fisheries
Service (NMFS) Fisheries Statistics Survey are presented in Exhibit 3-6 for recreational fish
catch in Gulf of Mexico states, excluding Texas. Texas data are maintained by the state and not
reported to NMFS.
Commercial Shrimp
Gulf of Mexico commercial shrimp fisheries include mainly brown, pink, white, and
northern shrimp. According to NMFS (1997), the commercial shrimp landings in the Gulf of
Mexico represented 72% and 70% of the total US landings by weight in 1995 and 1996,
respectively with 219.8 million and 218.6 million pounds of shrimp landed each year. The value
of these shrimp represented 77% and 79% of the total US shrimp landings by weight for those
respective years at $437 million and $401 million. The commercial shrimp landings for Gulf of
Mexico states is presented in Exhibit 3-7.
As presented in the offshore Environmental Assessment (Avanti Corporation, 1993), the
state reporting the landing does not necessarily represent the state in which the shrimp were
caught. EPA has used the catch:landings ratios used in the offshore assessment to adjust the
landings figures by factors of 123% for Louisiana and 85% for Texas. Also, as developed for the
offshore analysis, the total catch is adjusted to calculate the portion caught in areas potentially
affected by SBF discharges, i.e., beyond 3 miles from shore. These calculations are presented in
Appendix A.
3.4.2 Cook Inlet, Alaska
Recreational Finftsh
Cook Inlet area waters provided over 50% of the total (saltwater and freshwater)
sportfishing days in Alaska in 1992 with an estimated 375,993 saltwater recreational fishing days
-------
3-12
Exhibit 3-6. Gulf of Mexico Recreational Fisheries Catch (pounds)
State
W. Florida
Alabama
Mississippi
Louisiana
Total
1995
17,570,384
3,801,411
849,152
3,136,809
25,357,756
1996
14,610,412
2,950,265
1,143,668
2,035,401
20,739,746
Average
16,090,398
3,375,838
996,410
2,586,105
23,048,751
Source: NMFS, 1998
Exhibit 3-7. Gulf of Mexico Commercial Shrimp Catch (pounds)
Shrimp
Species
Brown
1995
1996
Average
Northern
1995
1996
Average
Pink
1995
1996
Average
White
1995
1996
Average
Other
Marine
1995
1996
Average
Florida
1,234,564
664,345
949,455
17,192
—
17,192
18,069,106
23,753,839
20,911,473
1,169,910
949,053
1,059,482
1,175,400
1,224,820
1,200,110
Mississippi
10,782,239
8,187,562
9,484,901
-
—
-
130,102
165,568
147,835
4,299,183
1,927,839
3,113,511
-
-
-
Alabama
11,156,659
9,101,653
10,129,156
82,732
12,081
47,407
3,557,597
4,433,053
3,995,325
3,088,084
1,392,376
2,240,230
-
-
-
Louisiana
45,023,758
51,420,060
48,221,909
-
—
-
4,768
108,095
56,432
50,752,795
29,368,900
40,060,848
-
-
-
Texas
56,108,138
50,584,072
53,346,105
1,584
—
1,584
830,226
23,065,104
1,447,665
16,582,811
21,619,926
19,101,369
930,837
1,433,385
1,182,111
Total
124,305,358
119,957,692
122,131,525
101,508
12,081
57,587
22,591,799
30,525,659
26,558,729
75,892,783
55,258,094
65,575,439
2,106,237
2,658,205
2,382,221
Total Texas
and
Louisiana
101,131,896
102,004,132
101,568,014
1,584
0
1,584
834,994
2,173,199
1,504,097
67,335,606
50,988,826
59,162,216
930,837
1,433,385
1,182,111
Source: NMFS, 1998
-------
3-13
recorded (Mills, 1993). Most of the recreational fishing in the inlet is for halibut and chinook
salmon.
Commercial Shrimp
There has been no commercial shrimping in Cook Inlet since January 1, 1997. The Alaska
Board of Fisheries mandated closures for Inner Cook Inlet (Kachemak Bay) in 1988 and Outer
Cook Inlet since January 1997 (Beverage, 1998). These closures were due to insufficient
information on the biology and stock status of the coonstriped shrimp, which was the primary
species sought by Alaskan commercial shrimpers. There is no information that indicates that
these closures will be lifted in the near future.
3.4.3 Offshore California
Recreational Finfish
In southern California an estimated 958 people participated in 3,519 fishing trips in 1996
(NMFS, 1997). The fmfish catch reported for 1995 and 1996 were 4,771,722 pounds and
3,191,205 pounds, respectively (NMFS, 1997).
Commercial Shrimp
Commercial shrimping occurs in the same general location as oil and gas activities.
Primary species caught in offshore California waters are ridgeback and spot prawns. These two
species accounted for 5 percent of all the 1997 shrimp landings in California. There were
450,189 Ibs of spot prawn and 385,931 Ibs of ridgeback prawns landed in Southern California
ports in 1997 (CA DFG, 1998). Shrimping for ridgeback and spot prawns occurs in water depth
between 50 fathoms and 200 fathoms and outside state waters.
The CA Department of Fish and Game (CA DFG) records shrimp catch data in 6- by 10-
mile blocks. By identifying the blocks that are within the species' depth range and outside state
waters, shrimp catch can be expressed on a pounds per square mile basis. The depths were taken
from NOAA nautical charts and catch blocks were taken from Southern California Fisheries
Charts, provided by CA DFG. There were 44, 10-by-6 mile blocks that were identified as having
the 50- to 200-fathom depth range and existing outside state waters. From these blocks, a
shrimping area of 264,000 square miles was determined. Using the total pounds of ridgeback
and spot prawns reported in southern ports, a catch rate of 3.17 pounds of shrimp per square mile
is used in this analysis.
-------
4-1
4. WATER QUALITY ASSESSMENT
4.1 Introduction
EPA based the methodologies for assessing both surface and pore water quality impacts
from the discharge of SBF-cuttings on the methodologies used to assess the discharge of water-
based fluids (WBFs) and associated cuttings (WBF-cuttings) for the offshore effluent limitations
guidelines (ELG). The methodology for the offshore guidelines is presented in Avanti
Corporation, 1993. However, there are several major differences in the analyses, most notably
the absence of bulk drilling fluid discharges in the SBF guidelines. In the offshore ELG, these
bulk discharges were a major wastestream and numerous existing drilling fluid characterization
and transport studies were used as sources of data for the water quality assessment. In the current
SBF-cuttings discharge impact analysis, surface water quality assessments rely on modeling data
presented in a study (Brandsma, 1996) of the post-discharge transport behavior of oil and solids
from cuttings contaminated with oil-based fluids (OBF-cuttings). Due to the similar hydrophobic
and physical properties between SBFs and OBFs, EPA assumes that dispersion behavior of SBF-
cuttings is similar to that of OBF-cuttings.
In addition, the offshore ELG only examined impacts in the Gulf of Mexico. For the SBF
guidelines, EPA considered the impacts in offshore California and Cook Inlet, Alaska separately
from the Gulf of Mexico. Although the analysis methodology does not change between regions,
data used to conduct the water quality assessment contains certain assumptions specific to each
region, for example, current speed.
For the pore water quality assessment, the absence of bulk drilling fluid discharges
greatly affects the annual pollutant loadings. EPA applied the same methodology used for the
offshore ELG in assessing the effects of SBF-cuttings discharges on pore water quality for the
current industry practice and the discharge option.
The analyses in this chapter are conservative due to the assumption that discharged
pollutants immediately leach into the water column or into the pore water. In the water column,
total organic pollutant discharge concentrations are assumed to represent the soluble
concentration. Metals are assumed to leach immediately into the water column at pollutant-
specific amounts determined for mean seawater pH (as derived in Avanti Corporation, 1993;
Appendix C). In the pore water, pollutant-specific partition coefficients are used for organic
pollutants (from EPA's IRIS) to determine soluble concentrations. The mean seawater leach
factors are used for metals in the same manner as used for the water column concentrations. For
-------
4-2
both organic pollutants and metals, the total leached concentration is assumed to be immediately
available in the pore water.
In general, the methodology consists of modeling incremental water column and pore
water concentrations and comparing them to EPA water quality criteria/toxic values for marine
acute, marine chronic, and human health protection. Additionally, EPA used the proposed
sediment guidelines for protection of benthic organisms to assess potential impacts from a group
of select metals in pore water (EPA, 1998b). Note that all of these comparisons are performed
only for those pollutants for which EPA has numeric criteria. Those pollutants include priority
and nonconventional pollutants associated with the drilling fluid barite and with contamination
by formation (crude) oil, but do not include synthetic base fluids themselves. Potential impacts
from synthetic base fluid compounds are described in Chapters 6 through 9 of this document.
4.2 Surface Water
To help evaluate the relative water quality impacts of the current industry practice and
regulatory options, EPA estimates the water column concentration of pollutants present in SBF
drilling discharges under regulatory discharge options and compares them to Federal water
quality criteria/toxic values. This comparative analysis applies only to those pollutants for which
EPA has published numeric criteria, as presented in Exhibit 4-1.l Note that there are no criteria
for the synthetic-based fluid compounds themselves.
In order to determine the water column pollutant concentrations, EPA used data regarding
the transport of discharged drill solids and corresponding oil concentration in the water column.
The study was performed by Brandsma (1996) and the data are published in the April 1996 E&P
Forum Summary Report No. 2.61/202. Because of the extensive North Sea use of oil-based
drilling fluids (OBF) and discharge of OBF-cuttings, the E&P Forum sponsored the research
project to evaluate the modeled dispersement of treated versus untreated OBF-cuttings.
Following is a description of the Brandsma (1996) study from that E&P report.
Brandsma modeled the discharge of nine treatments of cuttings obtained from a North
Sea drilling platform to obtain: (1) a maximum deposition density (g/m2) of cuttings and oil; (2)
Subsequent to finalization of the analyses contained in this chapter, EPA published revised water quality
criteria (63 FR 68354, December 10, 1998). The following changes affect this Environmental Assessment water
quality analyses and will be reflected in the final rule: arsenic human health criterion is deleted; copper acute
criterion is raised to 4.8 ug/1 and copper chronic criterion is raised to 3.1 ug/1; mercury chronic criterion is raised to
0.94 ug/1 and mercury human health is reduced to 0.051 ug/1; and phenol human health criterion is deleted.
Appendix B contains the December 1998 criteria recommendations and an analysis of how the water quality
assessment would change using these revised criteria.
-------
4-3
water column concentrations of suspended solids and oil; (3) the maximum thickness (cm) of
cuttings deposited on the seabed; and (4) the seabed area (ha) that would achieve a 100 ppm oil
content threshold in the upper 4 cm or 10 cm of the sediment.
Exhibit 4-1. Federal Water Quality Criteria
Pollutant
Antimony
Arsenic
Cadmium
Chromium (VI)
Copper
Lead
Mercury
Nickel
Phenol
Selenium
Silver
Thallium
Zinc
Marine Acute
Criteria
fog/1)
69
42
1,100
2.4
210
1.8
74
290
1.9
90
Marine Chronic
Criteria
fog/1)
36
9.3
50
2.4
8.1
0.025
8.2
71
81
Human Health
Criteria
fog/1) (a)
4,300
0.14
0.15
4,600
4,600,000
6.3
(a) Human health criteria for consumption of organisms only; risk factor of 10"6 for carcinogens.
Source: Tabulation of water quality criteria, EPA Health and Ecological Criteria Division, February 1997. See
footnote 1 (page 4-2) and Appendix B for information on criteria revision as of December 10, 1998.
The treatment technologies included: (1) no treatment (lab formulated control), (2)
untreated cuttings from shale shakers, (3) centrifugation, (4) solvent extraction, (5) thermal
treatment, and (6) water washing. The bulk densities of the cutting ranged from 1,830 g/1 to
2,430 g/1; oil content for the six types of cuttings ranged from 0.02% (dry weight basis) to 19.6%.
The author simulated four sites in the North Sea: Southern (30 m water depth and depth-
averaged, root mean-squared current speed of 0.37 m/s); Central (100 m water depth and current
speed of 0.26 m/s); Northern (150 m water depth and current speed of 0.22 m/s); and
Haltenbanken (250 m water depth and current speed of 0.10 m/s).
The Offshore Operators Committee (OOC) drilling and production discharge model was
used to simulate the concentrations and deposition of discharged cuttings. The OOC model
utilized a mixture of 12 profile size classes of mud and cuttings particles (with adsorbed oil) and
water. All other discharge conditions were fixed. All discharges simulated a 68.5-hour
discharge of 152 m3 of cuttings from a 0.3 m diameter pipe shunted to a depth of 15.2 m below
-------
4-4
mean sea level. This cuttings volume is the volume expected from a single well section of OBF-
cuttings. Results presented are based on these 152 m3 model efforts, however, results are scaled
up to a 300 m3 volume which was later determined by the project steering committee to be more
representative of actual OBF-cuttings volumes generated using OBFs (representing two well
sections).
Hydrographic conditions were conservatively selected to maximize predicted cuttings
deposition on the seabed by choosing the minimum water column stratification at each site. The
result is no density gradient at all sites but the Haltenbanken site, which exhibited only a weak
(0.0016 kg/m3/m) gradient.
Water column results were determined at a radial distance of 1000 m downstream. For
untreated and centrifuged OBF-cuttings, projected water column oil concentrations at 1000 m
were below maximum North Sea background levels at all four sites; all other treatments resulted
in projected 1000 m oil concentrations that exceeded maximum background levels (except
through treatment at the Haltenbanken site). The explanation for this apparent conundrum is that
while treatments other than centrifugation also reduce oil content (from an untreated level of
15.8% [w/w] to a range of 0.3% to 5.1%), these treatments also generate cuttings with finer
particle sizes. Thus, according to the model, the untreated and centrifuged OBF-cuttings would
not reach the 1000 m mark to the same extent that the treated OBF-cuttings would because the
finer particles created by the treatment have lower settling velocities and are transported farther
in the water column (Brandsma, 1996).
Although Brandsma (1996) does not present oil concentration data for a radial distance of
100 m (the edge of the mixing zone established for U.S. offshore discharges by Clean Water Act
Section 403, Ocean Discharge Criteria, as codified at 40 CFR 125 Subpart M), the study does
present data on suspended solids and oil concentration as a function of transport time. Using
current speeds representative of each geographic area (Gulf of Mexico; Cook Inlet, Alaska; and
offshore California) and the transport times reported by Brandsma, EPA derived the
corresponding oil concentrations and dilutions at 100 m. For example, assuming a mean current
speed of 15 cm/s as representative of the Gulf of Mexico, a transport time of approximately
11 minutes is derived as the time required for the plume to reach 100 m (100 m/0.15 m/sec).
From graphical analysis of the data presented in Figure 2 of Brandsma's 1996 study (provided in
Appendix C), the oil concentration can be determined for selected transport times. Based on the
mean initial oil concentration of the 9 cuttings cases presented in the study (5.5% in water-
washed cuttings), the dilutions achieved can be estimated for a selected time (i.e., distance) in the
following manner. The 5.5% (w/w) oil content converts to 55 g oil/kg wet cuttings. Based on a
reported mean OBF-cuttings density of 2.050 kg wet cuttings/1, the initial oil concentration of
112,750 mg oil/1 (55 g/kg x 2.050 kg/1) is used to determine the dilutions achieved. For the Gulf
-------
4-5
of Mexico example, the oil concentration at 11 minutes of 3.2 mg/1 is used to calculate a 35,234-
fold dilution (112,750 mg/3.2 mg) at 11 minutes. As described above, 11 minutes represents the
estimated time at which the plume would reach the edge of the mixing zone at 100 meters.
Projected water column pollutant concentrations at the edge of a 100-m mixing zone are
calculated by dividing the drilling waste pollutant concentration by the dilutions available. The
effluent concentrations for metals are further adjusted by a leach factor to account for the portion
of the total metal pollutant concentration that is dissolved and therefore available in the water
column. In terms of metal concentrations, this analysis is conservative in that it assumes that all
teachable metals are immediately leached into the water column.
Exhibit 4-2 summarizes the water quality analyses for Gulf of Mexico, Cook Inlet,
Alaska, and offshore California water column pollutant concentrations at 100 m from SBF-
cuttings discharges. The results show that no exceedances of any Federal or state water quality
criteria or standards are expected using current technology or the discharge option.
Exhibit 4-2. Summary of Water Column Water Quality Analyses
Discharge
Region
Gulf of Mexico
California
Cook Inlet,
Alaska
Shallow Water
Development
Current
Technology
»(b)
--
--
Discharge
Option
--
--
-
Exploratory
Current
Technology
--
NA(c)
NA
Discharge
Option
--
NA
NA
Deep Water
Development
Current
Technology
--
--
NA
Discharge
Option
--
--
NA
Exploratory
Current
Technology
--
NA
NA
Discharge
Option
--
NA
NA
(a) Current technology equals the Gulf of Mexico current industry practice of SBF-cuttings treatment to 11% SBF
retention on cuttings.
(b) — indicates no exceedances of Federal or state water quality criteria or standards from any of the discharged pollutants.
(c) NA = Not applicable; For Cook Inlet, Alaska and offshore California, EPA does not anticipate any exploratory drilling
to occur. In addition, EPA does not consider any of the drilling activity in Cook Inlet, Alaska to be in deep water (>
1,000ft).
-------
4-6
4.2.1 Gulf of Mexico
Exhibits 4-3 and 4-4 compare the projected pollutant concentrations for Gulf of Mexico
discharges of SBFs with the Federal water quality criteria under the discharge scenarios for the
current technology and the discharge option. For this analysis, and all subsequent water quality
and pore water quality analyses in this report, the zero discharge option is not presented in
tabular form. Because no drilling wastes are discharged under the zero discharge option, there
are no water quality criteria concerns to assess.
The water column pollutant concentrations for all four model wells (deep water
exploratory, deep water development, shallow water exploratory, and shallow water
development) are the same within each discharge scenario. This occurs because only the total
discharge volume for each of the model wells varies, not the discharge rate or individual
pollutant concentrations. The reader should also note that in the exhibits that follow, only the
most stringent water quality criterion is listed for each pollutant. Any exceedances of water
quality criteria are detailed in the footnotes of each table.
When comparing the Federal water quality criteria to the SBF concentration in the water
column at 100 meters from the discharge, no exceedances of any of the Federal water quality
criteria occurred for any model wells in the Gulf of Mexico using the current technology, nor
under either the discharge or zero discharge options.
4.2.2 Cook Inlet, Alaska
EPA compared pollutant concentrations resulting from the discharge of SBF-cuttings in
Cook Inlet, Alaska to both Federal criteria and state water quality standards because the
discharges occur in state waters. The Alaska standard for "toxic and other deleterious organic
and inorganic substances" states that "individual substances may not exceed criteria in EPA,
Quality Criteria for Water, or, if those do not exist, may not exceed the Primary Maximum
Contaminant Levels of the Alaska Drinking Water Standards (18 AAC 80)." The Alaska
standards for waters classified as marine waters for growth and propagation offish, shellfish, and
other aquatic life, and wildlife are presented in Exhibit 4-5.
-------
4-7
Exhibit 4-3. Water Column Pollutant Concentrations - Gulf of Mexico,
Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Pollutant Cone.
in Effluent
(mg/1) (a)
1.1700
0.6382
1.5136
0.0001
0.1707
0.0155
0.8843
1.1015
0.1086
37.2331
2.9011
5.4453
2.0944
0.1707
0.1086
0.1862
31.1051
1,407.0
18,616.5
2,380.5
2.2650
13.5746
6.5861
61.9177
7.4534
9.4169
0.0007
12.2395
0.0107
Trace Metal
Leach
Factor (b)
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Water Column
Cone, at 100 m
(mg/1) (c)
3.32e-05
1.81e-05
4.30e-05
2.39e-09
5.33e-07
7.93e-09
1.56e-07
3.59e-05
5.19e-07
3.09e-06
2.56e-06
3.92e-06
l.lle-03
8.78e-03
1.87e-04
1.76e-03
2.12e-04
2.67e-04
2.10e-08
3.47e-04
3.02e-07
Federal Water
Quality Criteria
(mg/1) (d)
1.406+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (e)
(a) See section 3.2 for effluent pollutant concentrations.
(b) Source: Offshore Environmental Assessment (Avanti, 1993); assumed to be 1 unless otherwise listed.
(c) Water column pollutant cone. = (avg. poll. cone, x leach factor)/dilutions (35,234 dilutions).
(d) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(e) No Federal water quality criteria are exceeded.
-------
4-8
Exhibit 4-4. Water Column Pollutant Concentrations - Gulf of Mexico,
Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Pollutant Cone.
in Effluent
(mg/1) (a)
0.811
0.442
1.049
0.0001
0.118
0.0108
0.613
0.763
0.0750
25.80
2.011
3.774
1.452
0.118
0.0750
0.129
21.56
975.2
12,902
1,650
1.570
9.408
4.566
42.93
5.167
6.529
0.0005
8.486
0.0074
Trace Metal
Leach
Factor (b)
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Water Column
Cone, at 100 m
(mg/1) (c)
2.30e-05
1.26e-05
2.98e-05
1.66e-09
3.69e-07
5.49e-09
1.08e-07
2.49e-05
3.59e-07
2.14e-06
1.77e-06
2.51e-06
7.69e-04
6.09e-03
1.30e-04
1.22e-03
1.47e-04
1.85e-04
1.46e-08
2.41e-04
2.10e-07
Federal Water
Quality Criteria
(mg/1) (d)
1.406+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (e)
(a) See section 3.2 for effluent pollutant concentrations.
(b) Source: Offshore Environmental Assessment (Avanti, 1993); assumed to be 1 unless otherwise listed.
(c) Water column pollutant cone. = (avg. poll. cone, x leach factor)/dilutions (35,234 dilutions).
(d) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(e) No Federal water quality criteria are exceeded.
-------
4-9
Exhibit 4-5. Alaska State Water Quality Standards
Pollutant
Antimony
Barium
Beryllium
Chromium
Nickel
Selenium
Thallium
Standard (mg/1)
6.00E-03
2.00E+00
4.00E-03
l.OOE-01
l.OOE-01
5.00E-02
2.00E-03
EPA determined the dilutions for assessment of compliance with water quality criteria
and standards using the same methodology as for the Gulf of Mexico analysis. A current speed
of 40 cm/sec was used (EPA Region 10, 1984), resulting in a transport time of 4.2 minutes to
reach the edge of the 100-meter mixing zone. The midpoint oil concentration from Brandsma
(1996) at 4 minutes is 28 mg/1. This concentration is a 4,027-fold dilution from the initial
discharge concentration of oil (112,750 mg/1).
The current operating practice in Cook Inlet, Alaska is zero discharge of SBF-cuttings.
However, for the purpose of comparison with the discharge option, an analysis of the current
technology (11% SBF retention on cuttings) is presented in Exhibit 4-6 for Cook Inlet, Alaska.
For the discharge option, Exhibit 4-7 presents the water column concentrations of pollutants at
100 meters from the discharge point and compares them to Federal water quality criteria and
Alaska state standards. Under the current technology and the discharge option, there are no
exceedances of the Federal criteria or state numerical standards in Cook Inlet, Alaska.
4.2.3 Offshore California
EPA compared pollutant concentrations resulting from the discharge of SBF-cuttings in
offshore California waters to Federal water quality criteria to determine compliance with these
guidelines. EPA determined the dilutions for assessment of compliance with water quality
standards using the same methodology as for the Gulf of Mexico analysis. A current speed of
30 cm/sec was used (MMS, 1985), resulting in a transport time of 5.5 minutes to reach the edge
of the 100-meter mixing zone. The midpoint oil concentration from Brandsma (1996) at 5
minutes is 20 mg/1. This concentration is a 5,638-fold dilution from the initial discharge
concentration of oil (112,750 mg/1).
-------
4-10
Exhibit 4-6. Water Column Pollutant Concentrations - Cook Inlet, Alaska,
Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Pollutant
Cone, in
Effluent
(mg/1) (a)
1.1700
0.6382
1.5136
0.0001
0.1707
0.0155
0.8843
1.1015
0.1086
37.2331
2.9011
5.4453
2.0944
0.1707
0.1086
0.1862
31.1051
1,407.0
18,616.5
2,380.5
2.2650
13.5746
6.5861
61.9177
7.4534
9.4169
0.0007
12.2395
0.0107
Trace
Metal
Leach
Factor (b)
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Water Column
Cone, at 100 m
(mg/1) (c)
2.91e-04
1.58e-04
3.76e-04
2.09e-08
4.66e-06
6.93e-08
2.20e-04
1.37e-06
2.70e-05
3.14e-04
4.54e-06
2.70e-05
2.24e-05
4.24e-05
2.70e-05
4.62e-05
3.17e-05
9.71e-03
7.68e-02
5.62e-04
3.37e-03
1.64e-03
1.54e-02
1.85e-03
2.34e-03
1.84e-07
3.04e-03
2.64e-06
Federal Water
Quality
Criteria
(mg/1) (d)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
State Water
Quality
Standards
(mg/1)
6.00e-03
5.00e-01
4.00e-03
l.OOe-01
l.OOe-01
5.00e-02
2.00e-03
2.00e+00
Criteria/
Standards
Exceed.
Factor (e)
(a) See section 3.2 for effluent pollutant concentrations.
(b) Source: Offshore Environmental Assessment (Avanti, 1993); assumed to be 1 unless otherwise listed.
(c) Water column pollutant cone. = (avg. poll. cone, x leach factor)/dilutions (4,027 dilutions).
(d) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(e) No Federal water quality criteria or state standards are exceeded.
-------
4-11
Exhibit 4-7. Water Column Pollutant Concentrations - Cook Inlet, Alaska,
Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Poll.
Cone, in
Effluent
(mg/1) (a)
0.811
0.442
1.049
0.0001
0.118
0.0108
0.613
0.763
0.075
25.80
2.011
3.774
1.452
0.118
0.075
0.129
21.56
975.2
12,902
1,650
1.570
9.408
4.566
42.93
5.167
6.529
0.0005
8.486
0.0074
Trace
Metal
Leach
Factor (b)
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Water Column
Cone, at 100 m
(mg/1) (c)
2.01e-04
1.10e-04
2.61e-04
1.45e-08
3.23e-06
4.81e-08
1.52e-04
9.48e-07
1.87e-05
2.18e-04
3.15e-06
1.87e-05
1.55e-05
2.94e-05
1.87e-05
3.20e-05
2.19e-05
6.73e-03
5.33e-02
3.90e-04
2.34e-03
1.13e-03
1.07e-02
1.28e-03
1.62e-03
1.28e-07
2.11e-03
1.83e-06
Federal Water
Quality
Criteria
(mg/1) (d)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
State Water
Quality
Standards
(mg/1)
6.00e-03
5.006-01
4.00e-03
l.OOe-01
l.OOe-01
5.00e-02
2.00e-03
2.00e+00
Criteria/
Standards
Exceed.
Factor (e)
(a) See section 3.2 for effluent pollutant concentrations.
(b) Source: Offshore Environmental Assessment (Avanti, 1993); assumed to be 1 unless otherwise listed.
(c) Water column pollutant cone. = (avg. poll. cone, x leach factor)/dilutions (4,027 dilutions).
(d) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(e) No Federal water quality criteria or state standards are exceeded.
-------
4-12
The current practice in offshore California is zero discharge of SBF-cuttings. However,
for the purpose of comparison with the discharge option, an analysis of the current technology
(11% SBF retention on cuttings) is presented in Exhibit 4-8 for offshore California. For the
discharge option, Exhibit 4-9 presents the water column concentrations of pollutants at 100
meters from the discharge point and compares them to Federal water quality criteria. Under both
current technology and the discharge option, there are no exceedances of the Federal water
quality criteria in offshore California.
4.3 Sediment Pore Water Quality
EPA calculated sediment pollutant levels based on the assumption of a uniform
distribution of the annual mass loadings of pollutants from model operations into a defined area
of impact. Using the derived sediment pollutant concentrations, EPA assessed sediment pore
water quality. A summary of the pore water quality analyses for discharges of SBF-cuttings in
the Gulf of Mexico, Cook Inlet, Alaska, and offshore California is presented in Exhibit 4-10.
4.3.1 Gulf of Mexico
To assess the pore water quality impacts of the discharge of SBF-cuttings on the benthic
environment, EPA determined the pollutant concentrations in the pore water for each model well
and each discharge scenario at the edge of the 100-meter mixing zone. EPA then compared these
projected pore water concentrations of pollutants from the SBF-cuttings to Federal water quality
criteria to determine the number of exceedances and the magnitude of each exceedance.
Following is a detailed explanation of the methodology used to assess pore water quality.
The pore water quality analysis of the offshore Effluent Limitations Guidelines
characterized sediment pollutants through a number of field surveys of both exploratory and
development operations. These surveys predominantly measured sediment barium content,
which was considered the best marker for assessing transport and fate of the particulate fraction
of water-based drilling fluids. In this current environmental assessment, EPA again assessed
field surveys but the sediment concentration of synthetic base fluid was considered the most
reliable marker of SBF-cuttings transport. EPA compiled sediment synthetic base fluid
concentration data from 5 surveys of 11 wells. Ten wells were drilled in the North Sea and one
in the Gulf of Mexico. If the survey data did not include data for a 100-m sampling location,
EPA linearly extrapolated the existing data points to 100 m. A summary of the 100-m sediment
synthetic base fluid concentrations is presented in Exhibit 4-11. For three of the wells listed in
the summary, data for two different sampling transects are included. Because concentrations
were averaged over different transects per well, that is, not consistently down current, the
-------
4-13
Exhibit 4-8. Water Column Pollutant Concentrations - Offshore California,
Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Pollutant
Cone, in
Effluent (mg/1)
(a)
1.1700
0.6382
1.5136
0.0001
0.1707
0.0155
0.8843
1.1015
0.1086
37.2331
2.9011
5.4453
2.0944
0.1707
0.1086
0.1862
31.1051
1,407.0
18,616.5
2,380.5
2.2650
13.5746
6.5861
61.9177
7.4534
9.4169
0.0007
12.2395
0.0107
Trace Metal
Leach
Factor (b)
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Water Column
Cone, at 100 m
(mg/1) (c)
2.08e-04
1.13e-04
2.68e-04
1.48e-08
3.33e-06
4.95e-08
1.57e-04
9.77e-07
1.93e-05
2.25e-04
3.24e-06
1.93e-05
1.60e-05
3.03e-05
1.93e-05
3.30e-05
2.26e-05
6.93e-03
5.49e-02
4.02e-04
2.41e-03
.17e-03
.10e-02
.32e-03
.67e-03
.31e-07
2.17e-03
1.89e-06
Federal Water
Quality Criteria
(mg/1) (d)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (e)
(a) See section 3.2 for effluent pollutant concentrations.
(b) Source: Offshore Environmental Assessment (Avanti, 1993); assumed to be 1 unless otherwise listed.
(c) Water column pollutant cone. = (avg. poll. cone, x leach factor)/dilutions (5,638 dilutions).
(d) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(e) No Federal water quality criteria are exceeded.
-------
4-14
Exhibit 4-9. Water Column Pollutant Concentrations - Offshore California,
Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Pollutant Cone.
in Effluent
(mg/1) (a)
0.811
0.442
1.049
0.0001
0.118
0.0108
0.613
0.763
0.075
25.80
2.011
3.774
1.452
0.118
0.075
0.129
21.56
975.2
12,902
1,650
1.570
9.408
4.566
42.93
5.167
6.529
0.0005
8.486
0.0074
Trace Metal
Leach
Factor (b)
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Water Column
Cone, at 100 m
(mg/1); (c)
1.44e-04
7.85e-05
1.86e-04
1.03e-08
2.10e-05
1.91e-06
1.09e-04
1.35e-04
1.33e-05
4.58e-03
3.57e-04
6.69e-04
2.57e-04
2.09e-05
1.33e-05
2.29e-05
3.82e-03
4.81e-03
3.80e-02
2.79e-04
1.67e-03
8.10e-04
7.61e-03
9.17e-04
1.16e-03
9.12e-08
1.51e-03
1.31e-06
Federal Water
Quality Criteria
(mg/1) (d)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal Criteria
Exceedance
Factor (e)
(a) See section 3.2 for effluent pollutant concentrations.
(b) Source: Offshore Environmental Assessment (Avanti, 1993).
(c) Water column pollutant cone. = (avg. poll. cone, x leach factor)/dilutions (5,638 dilutions).
(d) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(e) No Federal water quality criteria are exceeded.
-------
4-15
Exhibit 4-10. Summary of Pore Water Quality Analyses - Factors by Which Criteria are
Exceeded
Discharge
Region
Gulf of
Mexico
Cook Inlet,
Alaska
Offshore
California
Pollutant
Arsenic
Chromium
Mercury
Lead
Nickel
Arsenic
Arsenic
Shallow Water (a)
Development
Current
Tech-
nology
1.3
-
--
-
--
--
--
Discharge
Option
-(b)
-
--
-
--
--
--
Exploratory
Current
Tech-
nology
2.7
1.7
--
-
--
NA(c)
NA
Discharge
Option
--
-
--
-
--
NA
NA
Deep Water (a)
Development
Current
Tech-
nology
1.9
1.3
--
-
--
NA
1.2
Discharge
Option
1.1
-
--
-
--
NA
--
Exploratory
Current
Tech-
nology
4.3
2.8
1.2
1.5
1.2
NA
NA
Discharge
Option
2.5
1.6
--
-
--
NA
NA
(a) There would be no exceedances for any pollutants with the zero discharge option.
(b) - indicates that no exceedances are predicted.
(c) NA indicates that type of model well does not currently exist or is not projected for that geographic region.
resultant synthetic base fluid concentration represents the average concentration found at any
given point 100 m around a well as opposed to the maximum (i.e., down current) concentration.
Given the reported depths and discharge volumes of the studies, the calculated average
concentration most closely represents current practice for a Gulf of Mexico shallow water
exploratory model well.
In order to determine SBF-cuttings pollutant concentrations for other model well types,
EPA assumed that the relative concentrations or proportions between the base fluid and other
pollutants as found in the SBF are maintained after discharge and transport. Therefore, to project
the sediment concentration of each pollutant, EPA multiplied the ratio of each pollutant to the
synthetic base fluid by the average 100-m base fluid concentration (13,892 mg synthetic/kg for
the shallow water exploratory model well; see Exhibit 4-11). For each model well, this factor is
further adjusted to account for the varying total amount of oil (synthetic plus formation oil)
discharged. For example, EPA determined that the shallow development well would discharge
only 47.7% of the oil as the shallow exploratory well. Therefore, the sediment pollutant
concentrations for the shallow development well are 47.7% of those for the shallow exploratory
well. For the deep wells (using the shallow water exploratory well as 100%), these factors are
160.5% and 72.2% for exploratory and development well pollutants, respectively.
-------
4-16
Exhibit 4-11. Summary of Synthetic Base Fluid Concentrations at 100 Meters
Data Source
Candler et al., 1995
Daan et al., 1996
Smith and May, 1991 in
Schaanning, 1995
Baakeetal., 1992 in
Schaanning, 1995
Gj0s, 1995a in
Viketal., 1996a
Gj0s. 1995b in
Viketal., 1996a
Gj0s, 1992 & 1993 in
Viketal., 1996a
Larsen, 1995 in
Viketal., 1996a
Feldstedt, 1991 in
Viketal., 1996a
Study
Site/Location
MPI-895;
Gulf of Mexico
K14-13;
North Sea
Ula 7/12-9;
North Sea
Gyda2/l-9;
North Sea
Tordis Well;
North Sea
Loke Well;
North Sea
Sleipner A
Well;
North Sea
Sleipner 0
Well;
North Sea
Gyda2/l-9;
North Sea
Ula 2/7-29;
North Sea
Ula 7/12-A6
Depth
(m)
39
30
67
—
181 -
218
76-81
76-81
—
70
67
67
Base Fluid
Type
PAO
Ester
Ester
Ether
PAO
Ester
Ester
Ester
Ether
Acetal
Acetal
Average concentration at 100 meters (represents a Gulf of Mexico
shallow water exploratory model well)
Average concentration at 100 meters (excluding the 2 shallowest
discharges; represents Cook Inlet, Alaska and offshore California
shallow water exploratory model well)
Cone, at 100 m
(mg/kg) (a)
90,105
522.1
46,400
1,418
15,090
145.8
62;
622
3,850
420;
200
24,833;
10,000
815
13,892
8,655
(a)
More than one value per well represents values from different sampling transects.
-------
4-17
These sediment pollutant concentrations are converted into pore water concentrations.
For metals, the mean seawater leach factors of trace metals in barite are used. For organic
pollutants, partition coefficients are used to project pore water concentrations. Partition
coefficients estimate the ratio of sediment to pore water concentration as the product of the
fraction of organic carbon (foc) and the octanol-water partition coefficient (Kow). For sediments,
the Kow = the partition coefficient for organic particle carbon (Koc). Therefore, Ksed = foc * Koc.
Both the foc and Koc used for this analysis are presented in Exhibit 4-12 and are based on the
offshore environmental analysis (Avanti Corporation, 1993). The leach factors and partition
coefficients are summarized in Exhibit 4-12. The sediment concentration multiplied by the
pollutant specific leach factor or inverse of the partition coefficient results in the amount of
pollutant available in the pore water. To calculate the interstitial (pore water) concentration of
each pollutant, the available pollutant sediment concentration is multiplied by the dry weight of
sediment in a 1m x 1m x 0.05m unit volume and divided by the volume of water per unit volume
of sediment. Based on the offshore Environmental Assessment, the dry weight of sediment
equals 35.5 kg and the volume of pore water approximated from a dry sediment specific weight
of 2 g/ml is 32.5 1 (Avanti Corporation, 1993).
The calculated pore water concentrations of pollutants are then compared to their
respective EPA marine water quality criteria to determine the nature and magnitude of any
projected water quality exceedances. Exhibits 4-13 through 4-20 present the pore water quality
analyses and comparisons to the EPA water quality criteria for Gulf of Mexico discharges from
wells using the current and discharge option technologies.
4.3.2 Cook Inlet, Alaska and Offshore California
To assess the pore water quality impacts for Cook Inlet, Alaska and offshore California,
EPA again used the synthetic base fluid concentrations presented in Exhibit 4-11 to estimate the
concentration of synthetic fluids at 100 meters from the discharge. Due to the increased energy
and depth of Cook Inlet and offshore California, two of the studies in Exhibit 4-11 were
eliminated from the calculation of the average synthetic base fluid concentration at 100 meters.
Both of the eliminated studies included discharges in less than 40 meters total water depth
(Candler et al., 1995 and Daan et al., 1996).
-------
4-18
Exhibit 4-12. Trace Metal Leach Factors and Organic Pollutant Partition Coefficients
Trace Metal
Cadmium
Mercury
Arsenic
Chromium
Copper
Lead
Nickel
Zinc
Barium
Iron
Organic Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Mean Seawater Leach Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
„ , I/Partition
oc oc Coefficient
1,995 0.63% 0.0796
3,900 0.63% 0.0407
14,000 0.63% 0.0113
14 0.63% 11.34
Source: Offshore Environmental Assessment (Avanti Corporation, 1993).
-------
4-19
Exhibit 4-13. Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Development Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0529
0.0289
0.0684
3.80e-06
0.0077
0.0007
0.0400
0.0498
0.0049
1.6844
0.1312
0.2463
0.0947
0.0077
0.0049
0.0084
1.4072
63.6558
842.203
107.6918
0.1025
0.6141
0.2978
2.7998
0.3370
0.4258
0.0000
0.5534
0.0005
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
4.59e-03
1.28e-03
8.45e-04
4.71e-05
9.28e-04
1.38e-05
2.72e-04
6.26e-02
9.03e-04
5.38e-03
4.45e-03
6.30e-03
1.93e+00
1.53e+01
Federal Water
Quality Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
1.9
1.3
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
(c) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(d) Pore water pollutant concentration exceeds the water quality criteria for arsenic (human health) by a factor
of 1.9 and chromium (marine chronic) by a factor of 1.3.
-------
4-20
Exhibit 4-14. Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Exploratory Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.1177
0.0642
0.1523
8.46e-06
0.0172
0.0016
0.0890
0.1108
0.0109
3.7453
0.2918
0.5478
0.2107
0.0172
0.0109
0.0187
3.1289
141.5403
1,872.659
239.4554
0.2278
1.3655
0.6625
6.2284
0.7497
0.9473
0.0001
1.2312
0.0011
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
1.02e-02
2.85e-03
1.88e-03
1.05e-04
2.06e-03
3.07e-05
6.05e-04
1.396-01
2.01e-03
1.20e-02
9.90e-03
1.40e-02
4.30e+00
3.40e+01
Federal Water
Quality Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
1.2
4.3
2.8
1.5
1.2
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
(c) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(d) Pore water pollutant concentration exceeds the water quality criteria for mercury (marine chronic) by a
factor of 1.2, arsenic (human health) by a factor of 4.3, chromium (marine chronic) by a factor of 2.8, lead
(marine chronic) by a factor of 1.5, and nickel (marine chronic) by a factor of 1.2.
-------
4-21
Exhibit 4-15. Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Development Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0350
0.0191
0.0453
2.52e-06
0.0051
0.0005
0.0264
0.0329
0.0032
1.1131
0.0867
0.1628
0.0626
0.0051
0.0032
0.0056
0.9299
42.0670
556.571
71.1682
0.0677
0.4058
0.1970
1.8523
0.2230
0.2817
0.0000
0.3662
0.0003
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
3.04e-03
8.49e-04
5.59e-04
3.12e-05
6.13e-04
9.12e-06
1.80e-04
4.13e-02
5.97e-04
3.56e-03
2.94e-03
4.16e-03
1.28e+00
l.Ole+01
Federal Water
Quality Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
1.3
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
(c) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(d) Pore water pollutant concentration exceeds the water quality criterion for arsenic (human health) by a
factor of 1.3.
-------
4-22
Exhibit 4-16. Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Exploratory Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0732
0.0399
0.0947
5.26e-06
0.0107
0.0010
0.0554
0.0690
0.0068
2.3326
0.1818
0.3411
0.1312
0.0107
0.0068
0.0117
1.9487
88.1537
1,166.324
149.1369
0.1419
0.8504
0.4123
3.8760
0.4666
0.5895
0.0000
0.7662
0.0007
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
6.36e-03
1.78e-03
1.17e-03
6.52e-05
1.28e-03
1.91e-05
3.77e-04
8.66e-02
1.25e-03
7.45e-03
6.16e-03
8.73e-03
2.68e+00
2.12e+01
Federal Water
Quality Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
2.7
1.7
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
(c) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(d) Pore water pollutant concentration exceeds water quality criteria for arsenic (human health) by a factor of
2.7 and chromium (marine chronic) by a factor of 1.7.
-------
4-23
Exhibit 4-17. Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Development Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Poll. Cone.
in Sediment
at 100 m
(mg/kg) (a)
0.0303
0.0165
0.0392
2.18e-06
0.0044
0.0004
0.0229
0.0285
0.0028
0.9641
0.0751
0.1410
0.0542
0.0044
0.0028
0.0048
0.8054
36.4354
482.062
61.6409
0.0587
0.3515
0.1707
1.6045
0.1931
0.2440
0.0000
0.3172
0.0003
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
2.63e-03
7.35e-04
4.84e-04
2.70e-05
5.31e-04
7.90e-06
1.56e-04
3.58e-02
5.17e-04
3.08e-03
2.55e-03
3.61e-03
l.lle+00
8.75e+00
Federal Water
Quality
Criteria
(mg/1) (c)
1.406+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
1.1
(a)
(b)
(c)
(d)
Pollutant concentration in sediment calculation shown in Appendix D.
Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
Pore water pollutant concentrations exceed the water quality criterion for arsenic (human health) by a
factor of 1.1.
-------
4-24
Exhibit 4-18. Pore Water Pollutant Concentrations - Gulf of Mexico Deep Water
Exploratory Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0674
0.0368
0.0872
4.84e-06
0.0098
0.0009
0.0509
0.0634
0.0063
2.1437
0.1670
0.3135
0.1206
0.0098
0.0063
0.0107
1.7909
81.0149
1,071.874
137.0596
0.1304
0.7816
0.3793
3.5663
0.4293
0.5424
0.0000
0.7050
0.0006
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
5.85e-03
1.63e-03
1.08e-03
6.00e-05
1.18e-03
1.76e-05
3.46e-04
7.96e-02
1.15e-03
6.85e-03
5.66e-03
8.02e-03
2.46e+00
1.956+01
Federal Water
Quality
Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
2.5
1.6
(a)
(b)
(c)
(d)
Pollutant concentration in sediment calculation shown in Appendix D.
Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
Pore water pollutant concentrations exceed the water quality criteria for arsenic (human health) by a factor
of 2.5 and chromium (marine chronic) by a factor of 1.6.
-------
4-25
Exhibit 4-19. Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Development Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0201
0.0109
0.0260
1.44e-06
0.0029
0.0003
0.0151
0.0188
0.0019
0.6371
0.0496
0.0932
0.0358
0.0029
0.0019
0.0032
0.5323
24.0779
318.565
40.7346
0.0388
0.2323
0.1129
1.0618
0.1278
0.1615
0.0000
0.2099
0.0002
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
1.74e-03
4.87e-04
3.20e-04
1.79e-05
3.51e-04
5.22e-06
1.03e-04
2.37e-02
3.42e-04
2.04e-03
1.68e-03
2.38e-03
7.31e-01
5.78e+00
Federal Water
Quality
Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
(a)
(b)
(c)
(d)
Pollutant concentration in sediment calculation shown in Appendix D.
Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
No Federal water quality criteria are exceeded.
-------
4-26
Exhibit 4-20. Pore Water Pollutant Concentrations - Gulf of Mexico Shallow Water
Exploratory Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0419
0.0229
0.0542
3.01e-06
0.0061
0.0006
0.0317
0.0395
0.0039
1.3352
0.1040
0.1953
0.0751
0.0061
0.0039
0.0067
1.1154
50.4577
667.584
85.3634
0.0812
0.4868
0.2360
2.2188
0.2671
0.3374
0.0000
0.4386
0.0004
Partition
Coefficient7^!
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
(b)
3.64e-03
1.02e-03
6.69e-04
3.73e-05
7.35e-04
1.09e-05
2.16e-04
4.96e-02
7.16e-04
4.27e-03
3.53e-03
5.00e-03
1.53e+00
1.21e+01
Federal Water
Quality
Criteria
(mg/1) (c)
1.406+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
(a)
(b)
(c)
(d)
Pollutant concentration in sediment calculation shown in Appendix D.
Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
No Federal water quality criteria are exceeded.
-------
4-27
The resulting average base fluid concentration at 100 m (8,655 mg/kg) is used to calculate
the pore water concentrations of individual pollutants in synthetic fluids for a shallow water
exploratory model well. As for the Gulf of Mexico analysis, the concentration of base fluid at
100 meters is multiplied by the proportion of total oil discharged relative to a shallow exploratory
well to calculate the other model well type pollutant concentrations. These resulting
concentration at 100 meters for each pollutant is multiplied by the pollutant-specific leach factor
for metals or divided by the partition coefficient for organic pollutants to derive pore water
pollutant concentrations.
EPA projects that only development wells will be drilled in both Cook Inlet, Alaska
(shallow only) and offshore California (both shallow and deep). EPA does not project the
drilling of any exploratory wells in these areas, and for this reason model results concerning
exploratory wells are not shown. Although operators in Cook Inlet, Alaska and offshore
California currently cannot discharge SBF-cuttings, EPA presents pore water pollutant
concentrations for these areas based on the current treatment technology (11% retention on
cuttings) for the purpose of comparison with the discharge option results. The pore water
pollutant concentrations for the current technology and discharge option are compared to Federal
water quality criteria and Alaska state standards in Exhibits 4-21 through 4-24.
-------
4-28
Exhibit 4-21. Pore Water Pollutant Concentrations - California Deep Water Development
Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone, in
Sediment
at 100 m
(mg/kg) (a)
0.0330
0.0180
0.0426
2.37e-06
0.0048
0.0004
0.0249
0.0310
0.0031
1.0494
0.0818
0.1535
0.0590
0.0048
0.0031
0.0052
0.8767
39.6583
524.702
67.0932
0.0638
0.3826
0.1855
1.7443
0.2100
0.2653
0.0000
0.3448
0.0003
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore Water
Cone, (mg/1)
2.86e-03
7.99e-04
5.26e-04
2.93e-05
5.78e-04
8.60e-06
1.70e-04
3.90e-02
5.63e-04
3.35e-03
2.77e-03
3.93e-03
1.20e+00
9.53e+00
Federal Water
Quality Criteria
(mg/1) (b)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (c)
1.2
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(c) Pore water pollutant concentration exceeds the water quality criterion for arsenic (human health) by a
factor of 1.2.
-------
4-29
Exhibit 4-22. Pore Water Pollutant Concentrations - Cook Inlet, Alaska and Offshore
California Shallow Water Development Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone.
in Sediment
at 100 m
(mg/kg) (a)
0.0218
0.0119
0.0282
1.57e-06
0.0032
0.0003
0.0165
0.0205
0.0020
0.6935
0.0540
0.1014
0.0390
0.0032
0.0020
0.0035
0.5794
26.2082
346.750
44.3386
0.0422
0.2528
0.1227
1.1540
0.1389
0.1755
0.0000
0.2281
0.0002
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore
Water
Cone.
(mg/1) (b)
1.89e-03
5.29e-04
3.48e-04
1.94e-05
3.82e-04
5.68e-06
1.12e-04
2.58e-02
3.72e-04
2.22e-03
1.82e-03
2.60e-03
7.95e-01
6.30e+00
Federal Water
Quality
Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Alaska
State
Standards
(mg/1)
6.00e-03
5.00e-01
4.00e-03
l.OOe-01
l.OOe-01
5.00e-02
2.00e-03
2.00e+00
Criteria/
Standards
Exceedance
Factor (d)
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
(c) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(d) No Federal water quality criteria or state standards are exceeded.
-------
4-30
Exhibit 4-23. Pore Water Pollutant Concentrations - California Deep Water Development
Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone.
in Sediment
at 100 m
(mg/kg) (a)
0.0189
0.0103
0.0244
1.36e-06
0.0028
0.0003
0.0143
0.0178
0.0018
0.6007
0.0468
0.0878
0.0338
0.0028
0.0018
0.0030
0.5018
22.700
300.33
38.403
0.0365
0.2190
0.1063
0.9996
0.1203
0.1520
0.0000
0.1976
0.0002
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore
Water
Cone.
(mg/1) (b)
1.64e-03
4.58e-04
3.02e-04
1.68e-05
3.31e-04
4.92e-06
9.70e-05
2.23e-02
3.22e-04
1.92e-03
1.59e-03
2.25e-03
6.89e-01
5.45e+00
Federal Water
Quality
Criteria
(mg/1) (c)
1.40e+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Federal
Criteria
Exceedance
Factor (d)
(a)
(b)
(c)
(d)
Pollutant concentration in sediment calculation shown in Appendix D.
Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
No Federal water quality criteria are exceeded.
-------
4-31
Exhibit 4-24. Pore Water Pollutant Concentrations - Cook Inlet, Alaska and Offshore
California Shallow Water Development Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated
phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
Poll. Cone.
in Sediment
at 100 m
(mg/kg) (a)
0.0125
0.0068
0.0162
8.98e-07
0.0018
0.0002
0.0094
0.0117
0.0012
0.3969
0.0309
0.0581
0.0223
0.0018
0.0012
0.0020
0.3316
15.0008
198.470
25.3781
0.0241
0.1447
0.0704
0.6615
0.0796
0.1006
0.0000
0.1308
0.0001
Partition
CoefficientA-l
or Leach
Factor
0.0795
0.0407
0.0113
11.338
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
Pore
Water
Cone.
(mg/1) (b)
1.09e-03
3.03e-04
2.00e-04
l.lle-05
2.19e-04
3.25e-06
6.41e-05
1.47e-02
2.13e-04
1.27e-03
1.05e-03
1.49e-03
4.55e-01
3.60e+00
Federal Water
Quality
Criteria (mg/1)
(c)
1.406+01
4.60e+03
9.30e-03
2.50e-05
4.30e+00
1.40e-04
5.00e-02
2.40e-03
8.10e-03
8.20e-03
7.10e-02
1.90e-03
6.30e-03
8.10e-02
Alaska
State
Standards
(mg/1)
6.00e-03
5.00e-01
4.00e-03
l.OOe-01
l.OOe-01
5.00e-02
2.00e-03
2.00e+00
Criteria/
Standards
Exceedance
Factor (d)
(a) Pollutant concentration in sediment calculation shown in Appendix D.
(b) Pore water cone. = Poll. Cone, in Sediment * Partition Coeff1 or Leach Factor * 35.5 kg sediment/32.5 1
pore water
(c) Most stringent criterion shown on this table representing marine acute, marine chronic, and human health
(fish consumption) criteria (see Exhibit 4-1); there are no Federal water quality criteria for specific SBF
compounds.
(d) No Federal water quality criteria or state standards are exceeded.
-------
4-32 _
4.4 Sediment Guidelines for the Protection of Benthic Organisms
An additional method for assessing potential benthic impacts of certain metals is EPA's
proposed sediment guidelines for the protection of benthic organisms (EPA, 1998b). These
proposed guidelines are based on an equilibrium partitioning (EqP) approach to determine
guidelines based on "numerical concentrations for individual chemicals that are applicable across
the range of sediments encountered in practice." The EqP sediment guidelines (ESG) for the six
metals copper, cadmium, nickel, lead, silver, and zinc account for the additive toxicity effects of
these metals. They are derived by two procedures: (a) by comparing the sum of the metal's
molar concentrations, measured as simultaneously extracted metal (SEM), to the molar
concentration of acid volatile sulfide (AVS) in sediments:
£ [SEM] < [AVS]
or (b) by comparing the measured interstitial water [i.e., pore water] concentrations of the metals
to water quality criteria final chronic values (FCVs):
for the ith metal with a total dissolved concentration (M; d). Meeting one or both of these
conditions indicates that benthic organisms should be acceptably protected.
For this environmental analysis, the second (interstitial water guideline) method is used to
assess potential impacts. The pore water concentrations presented in section 4.3 are used for the
following analyses. The sum of the interstitial water concentration:FCV ratios for the six metals
is calculated for each of the model wells. Exhibits 4-25 and 4-26 present the ESG analysis for
Gulf of Mexico wells for current technology and the discharge option, respectively. Exhibit 4-27
presents the analysis for Cook Inlet, Alaska and offshore California model wells.
All model wells in the Gulf of Mexico fail to meet the sediment guidelines using the
current technology, with concentration:FCV ratios ranging from 1.2 to 3.9. Under the discharge
option, the development model wells meet the guideline. The exploratory model wells do not
meet the guideline, but the projected pollutant pore water concentrations are 43 percent lower
compared to those projected for the current industry practice. For Cook Inlet, Alaska and
offshore California, the deep and shallow development model wells pass the guidelines using
both the current technology and the discharge option technology.
-------
4-33
Exhibit 4-25. Sediment Guidelines Analysis - Gulf of Mexico, Current Technology
(a)
(b)
(c)
Metal
Pore Water
Cone. At 100 m
(Hg/D (a)
FCV
(Mg/0 (b)
Conc./FCV
(c)
Deep Water Development Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.928
0.903
5.38
4.45
-
6.30
9.3
2.4
8.1
8.2
-
81
0.0998
0.376
0.664
0.543
-
0.0778
Sum= 1.8
Deep Water Exploration Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
2.06
2.01
11.97
9.89
-
14.0
9.3
2.4
8.1
8.2
-
81
0.221
0.837
1.48
1.21
-
0.170
Sum= 3.9
Shallow Water Development Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.613
0.597
3.56
2.94
-
4.16
9.3
2.4
8.1
8.2
-
81
0.0659
0.249
0.439
0.358
-
0.0513
Sum= 1.7
Shallow Water Exploratory Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
1.28
1.25
7.45
6.16
-
8.73
9.3
2.4
8.1
8.2
-
81
0.138
0.521
0.920
0.752
-
0.108
Sum = 2.4
Pore water concentration calculated in Exhibits 4-13 through 4-16.
FCV = final chronic value = marine chronic water quality criterion.
The guideline is met if the sum of Conc./FCV is < 1. All Gulf of Mexico model wells exceed the sediment
guidelines using the current practice. See Appendix A for revised FCVs and analysis of changes to this
assessment due to the revisions. See footnote 1, page 4-2.
-------
4-34
Exhibit 4-26. Sediment Guidelines Analysis - Gulf of Mexico, Discharge Option
(a)
(b)
(c)
Metal
Pore Water
Cone. At 100 m
(Hg/1) (a)
FCV
(Mg/0 (b)
Conc./FCV
(c)
Deep Water Development Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.531
0.517
3.08
2.55
-
3.61
9.3
2.4
8.1
8.2
-
81
0.0571
0.215
0.380
0.311
-
0.0446
Sum= 1.0
Deep Water Exploratory Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
1.18
1.15
6.85
5.66
-
8.02
9.3
2.4
8.1
8.2
-
81
0.127
0.479
0.846
0.690
-
0.0990
Sum = 2.2
Shallow Water Development Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.351
0.342
2.04
1.68
-
2.38
9.3
2.4
8.1
8.2
-
81
0.0377
0.143
0.252
0.205
-
0.0294
Sum = 0.67
Shallow Water Exploratory Model Well
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.735
0.716
4.27
3.53
-
4.99
9.3
2.4
8.1
8.2
-
81
0.0790
0.298
0.527
0.430
-
0.0616
Sum= 1.4
Pore water concentration calculated in Exhibits 4-17 through 4-20.
FCV = final chronic value = marine chronic water quality criterion.
The guideline is met if the sum of Conc./FCV is < 1. The Gulf of Mexico exploratory model wells exceed
the sediment guidelines under the discharge option. See Appendix A for revised FCVs and analysis of
changes to this assessment due to the revisions. See footnote 1, page 4-2.
-------
4-35
Exhibit 4-27. Sediment Guidelines Analysis - Cook Inlet, Alaska and Offshore California
(a)
(b)
(c)
Metal
Pore Water
Cone. At 100 m
(Hg/D (a)
FCV
(Mg/1) (b)
Conc./FCV
Deep Water Development Model Well, Current Technology
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.578
0.563
3.35
2.77
-
3.93
9.3
2.4
8.1
8.2
-
81
0.0622
0.234
0.413
0.338
-
0.0485
Sum= 1.1
Deep Water Development Model Well, Discharge Option
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.331
0.322
1.92
1.59
-
2.25
9.3
2.4
8.1
8.2
-
81
0.0356
0.134
0.237
0.194
-
0.0278
Sum= 0.63
Shallow Water Development Model Well, Current Technology
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.382
0.372
2.22
1.83
-
2.59
9.3
2.4
8.1
8.2
-
81
0.0411
0.155
0.274
0.223
-
0.32
Sum= 0.73
Shallow Water Development Model Well, Discharge Option
Cadmium
Copper
Lead
Nickel
Silver
Zinc
0.219
0.213
1.27
1.05
-
1.48
9.3
2.4
8.1
8.2
-
81
0.0235
0.0887
0.157
0.128
-
0.0183
Sum = 0.42
Pore water concentration calculated in Exhibits 4-21 through and 4-24.
FCV = final chronic value = marine chronic water quality criterion.
The guideline is met if the sum of Conc./FCV is < 1. The Cook Inlet, Alaska and offshore California
development model wells meet the sediment guidelines under the discharge option. See Appendix A for
revised FCVs and analysis of changes to this assessment due to the revisions. See footnote 1, page 4-2.
-------
5-1
5. HUMAN HEALTH RISKS
5.1 Introduction
This portion of the environmental analysis presents the human health-related risks and
risk reductions (benefits) of current technology and the discharge and zero discharge regulatory
options. EPA based the health risks and benefits analysis on human exposure to carcinogenic
and noncarcinogenic contaminants through consumption of affected seafood; specifically,
recreationally-caught fmfish and commercially-caught shrimp. EPA used seafood consumption
and lifetime exposure duration assumptions to estimate risks and benefits under each of the
discharge scenarios for the three geographic regions where the discharge of SBF-cuttings will be
affected by this rule. The analysis is performed for those contaminants for which bioconcen-
tration factors, oral reference doses (RfDs), or oral slope factors for carcinogenic risks have been
established. Thus, the analysis considers contaminants associated with the drilling fluid barite
and with contamination by formation (crude) oil, but does not consider the synthetic base
compounds themselves.
5.2 Recreational Fisheries Tissue Concentrations
Exposure of recreational fmfish to drilling fluid contaminants occurs through the uptake
of dissolved pollutants found in the water column. Instead of using the water column pollutant
concentrations at the edge of the mixing zone (as for the water quality analyses), EPA calculates
an average water column concentration of each pollutant for the area within a 100-m radius of the
discharge. As described in Chapter 4, Brandsma's 1996 study was used to determine base fluid
concentrations at specified distances from a discharge point. Also as presented in Chapter 4,
Brandsma does not provide concentrations as a function of distance, but rather as a function of
time. Therefore, to calculate an average concentration within 100 m, the time required for
transport to the edge of the mixing zone was calculated as the quotient of the distance to the edge
of the mixing zone and the current speed (100 meters/current speed, in m/sec). Based on this
transport time, equal time intervals (and therefore radial distances) were chosen to create a series
of base fluid concentrations at varying radii across the total radius of the mixing zone. These
concentrations were used to calculate the dilutions achieved at these distances using the method
described in Chapter 4 (section 4.2). The average dilution for the area within 100 meters was
derived from these estimated dilutions between the discharge point and the 100-meter boundary.
The base fluid concentrations from Brandsma (1996), the calculated dilutions, and the average
dilutions used are presented below in the discussions for each geographic region.
-------
5-2
The average dilution available within 100 m is used to determine the ambient
bioavailable concentrations of pollutants associated with the SBF within the effluent plume by
multiplying the average number of dilutions by the respective initial pollutant concentrations.
For metals, these pollutant concentrations are further adjusted by leach factors to account for the
amount of the metal dissolved, and therefore, bioavailable. These dissolved metals remain in the
part of the plume that is diluted in the water column instead of settling to the seafloor with the
larger solids. This resulting exposure concentration of SBF pollutants characterizes only the area
within the discharge plume. Within the mixing zone, however, the water column also contains
"uncontaminated" waters. Thus, for the exposure of finfish within the 100-m mixing zone, the
effective exposure concentration is the exposure concentration adjusted by the volumetric
proportion of the total water column that contains the discharge plume. This volumetric
proportion represents the proportion of time that exposure would occur assuming the fish have an
equal probability of being present (and therefore exposed) anywhere in the entire cylinder that
makes up the mixing zone. This proportion is determined in the following manner:
exposure proportion = discharge plume volume/water column volume
= discharge rate (m3/min) * tT (time to reach 100 m; min)/7ir2h
where:
discharge rate = 25.1m3/day (= 0.0175 m3/min)
tT = 100 m/current speed (m/sec)
r = 100m
h = depth affected by the plume, which = fall velocity * tT;
where fall velocity = 0.015 m/sec (Delvigne, 1996).
The effective exposure concentration of each pollutant is multiplied by this exposure
proportion and by a pollutant-specific bioconcentration factor (BCF) to yield the tissue
concentration of each pollutant in finfish on a mg/kg basis. Pollutant-specific BCFs used for this
analysis are presented in Exhibit 5-1. These calculated tissue concentrations represent a potential
upper estimate of contamination for fish contained within a 100-m radius of a discharge of SBF-
cuttings. The following sections provide the geographic region-specific input parameters for the
tissue concentration calculations. The calculations and resulting finfish tissue pollutant
concentrations are presented in Appendix E.
5.2.1 Gulf of Mexico
The transport time for discharges in the Gulf of Mexico is based on a 15 cm/sec current
speed (MMS, 1989), resulting in an 11 minute estimation for the plume to reach 100 meters. The
time intervals used for the average dilutions within the mixing zone and the extracted base fluid
concentration data from Brandsma (1996) are presented in Exhibit 5-2. The tissue concentrations
-------
5-3
are presented in Appendix E, Exhibits E-l and E-2 for the current technology and discharge
option, respectively.
Exhibit 5-1. Pollutant-Specific Bioconcentration Factors
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
BCF(l/kg) (a)
426
30
2,630
1.4
64
5,500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(a) There are no BCFs for specific SBF compounds.
Source: Offshore Environmental Assessment (Avanti, 1993)
Exhibit 5-2. Calculation of Average Dilutions within Gulf of Mexico Mixing Zone
Time (t; min.)
Base fluid concentration
@t(mg/l)
Initial base fluid content in
cuttings (mg/1)
Calculated Dilutions
1
73
3
32
5
20
7
10
9
9
11
3.2
112,750
1,545
3,523
5,638
11,275
12,528
35,234
Avg.
11,624
Source: Derived from Figure 2, Brandsma (1996); see Appendix C.
-------
5-4
5.2.2 Cook Inlet, Alaska
The transport time for discharges in Cook Inlet, Alaska is based on a 40 cm/sec current
speed (EPA Region 10, 1984), resulting in a 4.2 minute estimation for the plume to reach 100
meters. The time intervals used to calculate the average dilutions within the mixing zone and the
extracted OBF concentration data from Brandsma (1996) are presented in Exhibit 5-3.
Exhibit 5-3. Calculation of Average Dilutions within Cook Inlet, Alaska and Offshore
California Mixing Zones
Time (t; min.)
Base fluid concentration
@ t (mg/1)
Initial base fluid concentration
in cuttings (mg/1)
Calculated Dilutions
Alaska (4.2 minutes)
California (5.5 minutes)
1
73
2
45.5
3
32
4
28
5
20
112,750
1,545
2,478
3,523
4,027
5,638
Avg.
2,893
3,442
Source: Derived from Figure 2, Brandsma (1996); see Appendix B.
The calculations for determining the finfish tissue concentrations including the
calculations of the proportion of the plume impacting Cook Inlet, Alaska mixing zones are
presented in Appendix E, Exhibits E-3 and E-4 for the current technology and the discharge
option, respectively. Although current practice in Cook Inlet, Alaska is zero discharge of SBF-
cuttings, the analysis of current technology is presented for comparison with the discharge
option.
5.2.3 Offshore California
The transport time for discharges offshore California is based on a 30 cm/sec current
speed (MMS, 1985), resulting in a 5.5 minute estimation for the plume to reach 100 meters. The
time intervals used to calculate the average dilutions within the mixing zone and the extracted
base fluid concentration data from Brandsma (1996) are presented in Exhibit 5-3, above.
The calculations for determining the finfish tissue concentrations including the
calculations of the proportion of the plume impacting offshore California mixing zones are
presented in Appendix E, Exhibits E-5 and E-6 for current technology and the discharge option,
-------
5-5
respectively. Although current practice in offshore California is zero discharge of SBF-cuttings,
the analysis of current technology is presented for the purpose of comparison with the discharge
option.
5.3 Commercial Fisheries Shrimp Tissue Concentrations
EPA based projected shrimp tissue concentrations of pollutants from SBF discharges on
the uptake of pollutants from sediment pore water. The pore water pollutant concentrations are
based on the assumption of even distribution of the total annual SBF discharge over an area of
impact surrounding the model well. The area of impact was determined using the 11-well
synthetic fluid sediment concentration data described in section 4.3.1. For each distance from the
well, the corresponding sediment concentrations of synthetic base fluids were averaged and
plotted (see Exhibit 5-4).
Based on a loglog regression of these data, the distances to various concentrations of
synthetic base fluids were determined (i.e., order of magnitude sediment concentrations ranging
from 1 mg/kg to 100,000 mg/kg). A study by Berge (1996) observed the environmental effects
(faunal changes) of treated OBF-cuttings on a natural seabed. Based upon the analyses provided
in Berge (1996), a no effect threshold was set at 100 mg/kg. The radial distance to that sediment
concentration (772 m as determined in Exhibit 5-4) results in an associated impact area of 1.9
km2, which is used for the analyses presented in this section.
While Berge indicates the usage of a 1,000 mg/kg threshold can be determined from data
in the study, the analyses are confounded by the statistical necessity of combining the data set
into low and high synthetic base fluid content groupings for the analyses. The low synthetic base
fluid content group was composed of cuttings treatments that resulted in residual base fluid levels
of 150 mg/kg and 990 mg/kg. Thus, Berge also offers that the no effect concentration found in
the experiments ranged from 150 ppm to 1,000 ppm of base fluid in sediment. For this analyses,
therefore, a no effect threshold of 100 mg/kg is used.
In order to calculate the discharge pollutant distribution over the 1.9 km2 impact area, the
following assumptions that were applicable in the Environmental Assessment for the offshore
effluent guidelines are used for this current SBF assessment (Avanti Corporation, 1993):
Sediment depth affected = 5 cm
• Unit volume sediment affected = 0.05 m3
• Density of sediment = 710 kg/m3
• Mass of unit volume sediment = 35.5 kg
• Volume of water in unit volume of sediment = 32.5 liters
-------
5-6
Impact radius = 772 m; impact area =1.9 km2
• Sediment mass = (impact area * sed. depth * sediment density) =
1.9 x 106 m2 * 0.05 m * 710 kg/m3 = 6.745e+07 kg
• Average pollutant concentration (mg poll. / kg sed.) = poll, loadings / sed. mass
Shrimp tissue concentration = (avg. poll, cone.) * (leach factor or partition coeff."1) *
35.5 kg sediment/32.5 1 water * (BCF) * (% lipids).
The above assumptions are used to calculate the average pollutant concentrations in pore
water at any point within the well impact area. The calculations of these sediment pollutant
concentrations for Gulf of Mexico SBF-cuttings discharges are presented in Appendix F. To
obtain the pollutant concentrations in shrimp tissue, the pore water concentration is multiplied by
a pollutant-specific BCF, and is adjusted for a shrimp lipid content of 1.1% (Avanti Corporation,
1993). The bioconcentration factors used in the current analysis are listed in Exhibit 5-1. The
following sections (5.3.1 through 5.3.3) present the input parameters for calculating the shrimp
tissue pollutant concentration for each of the geographic areas (Gulf of Mexico, Cook Inlet,
Alaska, and offshore California) using the current technology (11% retention on cuttings) or the
discharge option (7% retention on cuttings). The shrimp tissue concentrations do not serve as
endpoints for this analysis, but rather are used for estimating the health risks presented in section
5.5 of this chapter.
5.3.1 Gulf of Mexico
The concentrations of pollutants in shrimp tissue are presented in Appendix G, Exhibits
G-l through G-4 for Gulf of Mexico model wells using current technology and the discharge
option. Only shallow water wells are considered for shrimp impact analysis because shrimp are
harvested mainly from waters potentially affected by drilling discharges from shallow water
development and exploratory model wells.
5.3.2 Cook Inlet, Alaska
Shrimp harvesting by trawling or pot fishing is prohibited in Cook Inlet, Alaska by the
Alaska Board of Fisheries due to inadequate information regarding the biology and stock status
of shrimp in Cook Inlet waters (Beverage, 1998). Emergency Orders (AK Rule 2-S-H-l 1-96 and
AK Rule 5 AAC 31.390; AK Dept. of Fish & Game, 1998) were issued for Inner Cook Inlet and
Outer Cook Inlet in 1996 and 1997, respectively. A previous rule prohibiting shrimp harvesting
in Inner Cook Inlet dates back to 1988. There is currently no evidence that these orders will be
lifted in the near future. Therefore, human health effects from exposure to commercial shrimp
harvests were not analyzed for Cook Inlet, Alaska SBF-cuttings discharges.
-------
5-7
Exhibit 5-4. Arithmetically-Averaged Concentration Data
Reid-collected data
Regression Output:
X Coefficient(s) -1.5267
Std Err of Coef: 0.350
Constant: 14.7567
StdErrofYEst: 1.350
R Squared: 0.679
No. of observations: 11
Degrees of freedom: 9
1000
teH DstancefnomDschage(rrj
Regression Equation:
y=1.5267*x+14.7567
x(m)
(distance)
Y (mg/1)
(cone.)
Impact
Area
38
171
112
3,490
15,768
100,000
10,000
1,000
100
10
1
0.0002
0.004
0.1
1.9
38
781
5.3.3 Offshore California
The concentrations of pollutants in shrimp tissue are presented in Appendix G, Exhibits
G-5 and G-6 for offshore California model wells using the current technology and discharge
option, respectively. Only shallow water development model wells are considered for shrimp
impact analysis because shrimp are harvested mainly from waters potentially affected by shallow
water wells and there are no exploration wells in offshore California. The calculations of the
sediment pollutant concentrations for offshore California SBF-cuttings discharges are presented
in Appendix F.
-------
5-8
5.4 Noncarcinogenic and Carcinogenic Risk - Recreational Fisheries
The concentration of pollutants in finfish tissue is used to calculate the risk of
noncarcinogenic and carcinogenic (arsenic only) risk from ingestion of recreationally-caught fish.
For this analysis, the 99th percentile intake rate of 177 g/day (uncooked basis) is used as the
exposure for high-end seafood consumers in the general adult population (SAIC, 1998). This
analysis is a worst case scenario because the seafood consumed is assumed to consist only of
contaminated finfish.
For noncarcinogenic risk evaluation, the tissue pollutant concentration (mg/kg) is
multiplied by the consumption rate (mg/kg/day) for a 70 kg individual. This value is compared
to the oral reference dose (RfD) to determine the hazard quotient (HQ) for each pollutant in
accordance with the following equations:
HQ = GDI/RfD
where
HQ = hazard quotient (unitless)
GDI = chronic daily intake (mg/kg/day)
RfD = reference dose (mg/kg/day)
and
GDI = (TR * TPC) / BW
where
IR = intake rate (0.177 kg/day)
TPC = tissue pollutant concentration (mg/kg)
BW = body weight (70 kg)
The RfD is based on the assumption that thresholds exist for certain toxic effects to occur. These
thresholds are estimates of a daily exposure to humans that is likely to be without an appreciable
risk of deleterious effects during a lifetime. Therefore, if the hazard quotient is less than or equal
to one, toxic effects are considered unlikely to occur. The oral RfDs used in this analysis are
from EPA's Integrated Risk Information System (IRIS) database (EPA, 1998c) and are
summarized in Exhibit 5-5. For those pollutants without a published oral RfD, no hazard
quotient is calculated.
-------
Exhibit 5-5. Oral Reference Doses and Slope Factors
5-9
Pollutant
Napththalene
Fluorene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Chromium
Nickel
Selenium
Silver
Thallium
Zinc
Barium
Oral RfD
(mg/kg-day)
2.00e-02
4.00e-02
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
3.00e-03
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.00e-01
7.00e-02
Slope Factor
(mg/kg-day) ~l (a)
NA
NA
NA
NA
NA
NA
1.50e+00
NA
NA
NA
NA
NA
NA
NA
(a) NA indicates that a slope factor is not available for that pollutant; there are no slope factors for
specific SBF compounds.
Source: EPA, 1998b; Integrated Risk Information System (IRIS).
To calculate the carcinogenic risks, the slope factor as provided by IRIS is used to
estimate the lifetime excess cancer risk that could occur from ingestion of contaminated seafood.
The cancer risks are calculated in accordance with the following equations:
CR = GDI * SF
where
CR = cancer risk (unitless)
CDI = chronic daily intake (mg/kg/day)
SF = slope factor (mg/kg/day)"1
and
CDI = (TR * TPC * EF * ED) / (BW * AT)
where
IR = intake rate (0.177 kg/day)
TPC = tissue pollutant concentration (mg/kg)
EF = exposure frequency (365 days/yr)
ED = exposure duration (two exposure durations considered in this analysis:
30 years and 70 years)
-------
5-10
BW = body weight (70 kg)
AT = averaging time (70 year lifetime * 365 days/yr)
For this analysis, only arsenic has a slope factor available for estimation of the lifetime excess
cancer risk. The risk calculations for arsenic are performed considering a 30-year exposure
period and a 70-year exposure period. For the purposes of this analysis, a risk level of 1 x 10"6 is
considered to be acceptable.
Exhibit 5-6 presents a summary of the health risks from ingestion of recreationally-caught
finfish from around SBF-cuttings discharges under current technology and the discharge option.
Although current practice in Cook Inlet, Alaska and offshore California is zero discharge of SBF-
cuttings, the current technology analysis is presented for comparison purposes. None of the
hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur. Also all of the
lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
5.4.1 Gulf of Mexico
The noncarcinogenic and carcinogenic health risks for Gulf of Mexico recreational
fisheries are presented in Exhibits 5-7 and 5-8 for current technology and the discharge option,
respectively. Based on the 99th percentile consumption rate, the hazard quotients for
noncarcinogenic risks and the lifetime excess cancer risk estimates for carcinogens (arsenic) are
well below the acceptable risk levels adopted by the Agency for this analysis.
5.4.2 Cook Inlet, Alaska
The noncarcinogenic and carcinogenic health risks for Cook Inlet, Alaska recreational
fisheries are presented in Exhibits 5-9 and 5-10 for the current technology and the discharge
option, respectively. Although current practice in Cook Inlet, Alaska is zero discharge of SBF-
cuttings, the current technology analysis is presented for comparison purposes. Based on the 99th
percentile consumption rate, the hazard quotients for noncarcinogenic risks and the lifetime
excess cancer risk estimate for carcinogens (arsenic) are well below the acceptable risk levels
adopted by the Agency for this analysis.
-------
5-11
Exhibit 5-6. Summary of Finfish Health Risks
Pollutant
Gulf of Mexico
Current
Technology
Discharge
Option
Cook Inlet, Alaska
Current
Technology
Discharge
Option
Offshore California
Current
Technology
Discharge
Option
99th Percentile Hazard Quotient (a, b)
Naphthalene
Fluorene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Chromium
Nickel
Selenium
Silver
Thallium
Zinc
3.85e-05
7.39e-07
3.60e-13
1.86e-06
7.90e-06
3.41e-06
1.25e-06
1.04e-05
3.27e-07
2.53e-07
1.68e-08
4.17e-04
3.09e-08
2.67e-05
5.12e-07
3.60e-13
1.29e-06
5.50e-06
2.37e-06
8.65e-07
7.23e-06
2.27e-07
1.75e-07
1.16e-08
2.89e-04
2.14e-08
3.91e-05
7.50e-07
3.66e-13
1.88e-06
8.02e-06
3.46e-06
1.27e-06
1.06e-05
3.32e-07
2.57e-07
1.70e-08
4.23e-04
3.13e-08
2.71e-05
5.20e-07
3.66e-13
1.31e-06
5.59e-06
2.40e-06
8.77e-07
7.33e-06
2.30e-07
1.78e-07
1.18e-08
2.93e-04
2.17e-08
3.72e-06
7.14e-08
3.48e-14
1.79e-07
7.63e-07
3.30e-07
1.21e-07
l.Ole-06
3.16e-08
2.45e-08
1.62e-09
4.03e-05
2.98e-09
2.58e-06
4.95e-07
3.48e-14
1.24e-07
5.32e-07
2.29e-07
8.35e-08
6.98e-07
2.19e-08
1.69e-08
1.12e-09
2.79e-05
2.07e-09
Lifetime Excess Cancer Risk (c, d)
Arsenic
30-yr exposure
70-yr exposure
2.41e-10
5.61e-10
1.67e-10
3.89e-10
2.44e-10
5.70e-10
1.69e-10
3.95e-10
2.32e-ll
5.42e-12
1.616-11
3.76e-12
(a) Only pollutants for which there is an oral RfD are presented in this summary table.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) Only pollutants for which there is a slope factor are presented in this summary table.
(d) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
-------
5-12
Exhibit 5-7. Recreational Finfish Health Risks - Gulf of Mexico, Current Technology
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
3.04e-04
1.17e-05
2.43e-03
8.55e-ll
7.34e-07
9.37e-07
5.40e-07
1.48e-07
1.26e-06
1.24e-05
4.02e-07
3.26e-06
2.59e-06
5.01e-07
3.32e-08
1.32e-05
3.66e-06
1.99e-01
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
7.70e-07
2.96e-08
6.15e-06
2.16e-13
1.86e-09
2.37e-09
1.37e-09
3.74e-10
3.19e-09
3.13e-08
1.02e-09
8.24e-09
6.54e-09
1.27e-09
8.396-11
3.34e-08
9.26e-09
5.02e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
3.85e-05
7.39e-07
3.60e-13
1.86e-06
7.90e-06
3.41e-06
1.25e-06
1.04e-05
3.27e-07
2.53e-07
1.68e-08
4.17e-04
3.09e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcingenic Risk -
Arsenic Only:
30 yr: 1.50e+00 2.41e-10
70 yr: 1.50e+00 5.61e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * 0.177 (kg/day) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-13
Exhibit 5-8. Recreational Finfish Health Risks - Gulf of Mexico, Discharge Option
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
2.11e-04
8.11e-06
1.69e-03
8.55e-ll
5.09e-07
6.53e-07
3.74e-07
1.03e-07
8.74e-07
8.57e-06
2.79e-07
2.26e-06
1.79e-06
3.47e-07
2.30e-08
9.14e-06
2.54e-06
1.38e-01
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
5.34e-07
2.05e-08
4.26e-06
2.16e-13
1.29e-09
1.65e-09
9.46e-10
2.59e-10
2.21e-09
2.17e-08
7.04e-10
5.71e-09
4.53e-09
8.77e-10
5.826-11
2.31e-08
6.42e-09
3.48e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
2.67e-05
5.12e-07
3.60e-13
1.29e-06
5.50e-06
2.37e-06
8.65e-07
7.23e-06
2.27e-07
1.75e-07
1.16e-08
2.89e-04
2.14e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcingenic Risk -
Arsenic Only:
30 yr: 1.50e+00 1.67e-10
70 yr: 1.50e+00 3.89e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * 0.177 (kg/day) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-14
Exhibit 5-9. Recreational Finfish Health Risks - Cook Inlet, Alaska, Current Technology
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
3.09e-04
1.19e-05
2.47e-03
8.68e-ll
7.45e-07
9.51e-07
5.48e-07
1.50e-07
1.28e-06
1.26e-05
4.08e-07
3.31e-06
2.62e-06
5.08e-07
3.37e-08
1.34e-05
3.72e-06
2.01e-01
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
7.81e-07
3.00e-08
6.24e-06
2.19e-13
1.88e-09
2.40e-09
1.39e-09
3.80e-10
3.23e-09
3.17e-08
1.03e-09
8.36e-09
6.63e-09
1.28e-09
8.516-11
3.38e-08
9.39e-09
5.09e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
3.91e-05
7.50e-07
3.66e-13
1.88e-06
8.02e-06
3.46e-06
1.27e-06
1.06e-05
3.32e-07
2.57e-07
1.70e-08
4.23e-04
3.13e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcingenic Risk -
Arsenic Only:
30 yr: 1.50e+00 2.44e-10
70 yr: 1.50e+00 5.70e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * 0.177 (kg/day) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-15
Exhibit 5-10. Recreational Finfish Health Risks - Cook Inlet, Alaska, Discharge Option
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
2.14e-04
8.23e-06
1.71e-03
8.68e-ll
5.16e-07
6.63e-07
3.80e-07
1.04e-07
8.87e-07
8.70e-06
2.83e-07
2.29e-06
1.82e-06
3.52e-07
2.33e-08
9.27e-06
2.57e-06
1.40e-01
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
5.41e-07
2.08e-08
4.32e-06
2.19e-13
1.31e-09
1.68e-09
9.60e-10
2.63e-10
2.24e-09
2.20e-08
7.15e-10
5.80e-09
4.60e-09
8.90e-10
5.906-11
2.34e-08
6.51e-09
3.53e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
2.71e-05
5.20e-07
3.66e-13
1.31e-06
5.59e-06
2.40e-06
8.77e-07
7.33e-06
2.30e-07
1.78e-07
1. 18e-08
2.93e-04
2.17e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcingenic Risk -
Arsenic Only:
30 yr: 1.50e+00 1.69e-10
70 yr: 1.50e+00 3.95e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * 0.177 (kg/day) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-16
5.4.3 Offshore California
The noncarcinogenic and carcinogenic health risks for offshore California recreational
fisheries are presented in Exhibits 5-11 and 5-12 for current technology and the discharge option,
respectively. Although current practice in offshore California is zero discharge of SBF-cuttings,
the current technology analysis is presented for comparison purposes. Based on the 99th
percentile consumption rate, the hazard quotients for noncarcinogenic risks and the lifetime
excess cancer risk estimate for carcinogens (arsenic) are well below the acceptable risk levels
adopted by the Agency for this analysis.
5.5 Noncarcinogenic and Carcinogenic Risk - Commercial Shrimp
To calculate the noncarcinogenic and carcinogenic health risks for commercial shrimp,
the methodology is the same as that used for recreational finfish. However, instead of calculating
an effective exposure concentration that describes the portion of the water affected within the
mixing zone, the exposure is adjusted by the amount of the total commercial shrimp catch
affected. This is estimated by prorating the total potential exposure (total catch) by the portion of
the total shrimp catch affected by the well type being analyzed. The shrimp catch is assumed to
occur evenly over the area occupied by the species harvested. As calculated for the offshore
effluent guidelines Environmental Assessment, the total catch is divided by the populated area to
yield a catch density in lbs/mi2 (Avanti Corporation, 1993). This catch density is multiplied by
the area affected for each model well under current technology and the discharge option (number
of wells * 1.9 km2) and divided by the total catch to calculate a percent of the catch affected by
the SBF-cuttings discharge. Only shallow water model wells are used in this assessment due to
the limited shrimp harvesting that occurs in water depths greater than 1,000 feet.
Exhibit 5-13 presents a summary of the health risks from ingestion of commercially-
caught shrimp. None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted
to occur. Also all of the lifetime excess cancer risks are less than 10"6 and are, therefore,
acceptable.
-------
5-17
Exhibit 5-11. Recreational Finfish Health Risks - Offshore California, Current Technology
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
2.94e-05
1.13e-06
2.35e-04
8.26e-12
7.09e-08
9.06e-08
5.22e-08
1.43e-08
1.22e-07
1.20e-06
3.88e-08
3.15e-07
2.50e-07
4.84e-08
3.20e-09
1.27e-06
3.54e-07
1.92e-02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
7.44e-08
2.86e-09
5.94e-07
2.09e-14
1.79e-10
2.29e-10
1.32e-10
3.626-11
3.08e-10
3.02e-09
9.82e-ll
7.96e-10
6.32e-10
1.22e-10
8.10e-12
3.22e-09
8.94e-10
4.85e-05
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.00e-01
NA
7.00e-02
NA
NA
NA
3.72e-06
7.14e-08
3.48e-14
1.79e-07
7.63e-07
3.30e-07
1.21e-07
l.Ole-06
3.16e-08
2.45e-08
1.62e-09
4.03e-05
2.98e-09
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 2.32e-ll
70 yr: 1.50e+00 5.42e-12
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * 0.177 (kg/day) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-18
Exhibit 5-12. Recreational Finfish Health Risks - Offshore California, Discharge Option
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
2.04e-05
7.83e-07
1.63e-04
8.26e-12
4.91e-08
6.31e-08
3.62e-08
9.91e-09
8.44e-08
8.28e-07
2.69e-08
2.18e-07
1.73e-07
3.35e-08
2.22e-09
8.83e-07
2.45e-07
1.33e-02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
5.16e-08
1.98e-09
4.12e-07
2.09e-14
1.24e-10
1.60e-10
9.14e-ll
2.516-11
2.13e-10
2.09e-09
6.80e-ll
5.52e-10
4.38e-10
8.476-11
5.62e-12
2.23e-09
6.20e-10
3.36e-05
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.00e-01
NA
7.00e-02
NA
NA
NA
2.58e-06
4.95e-07
3.48e-14
1.24e-07
5.32e-07
2.29e-07
8.35e-08
6.98e-07
2.19e-08
1.69e-08
1.12e-09
2.79e-05
2.07e-09
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 1.61e-ll
70 yr: 1.50e+00 3.76e-12
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * 0.177 (kg/day) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-19
Exhibit 5-13. Summary of Shrimp Health Risks
Pollutant
Gulf of Mexico
Development
Current
Technology
Discharge
Option
Exploratory
Current
Technology
Discharge
Option
Offshore California
Current
Technology
Discharge
Option
99th Percentile Hazard Quotient (a)
Naphthalene
Fluorene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Chromium
Nickel
Selenium
Silver
Thallium
Zinc
4.71e-06
4.64e-08
5.28e-12
2.59e-06
1.10e-05
4.78e-06
1.74e-06
1.46e-05
4.57e-07
3.54e-07
2.34e-08
5.83e-04
4.32e-08
5.83e-05
5.70e-08
6.53e-12
3.19e-06
1.36e-05
5.91e-06
2.16e-06
1.80e-05
5.64e-07
4.35e-07
2.89e-08
7.21e-04
5.33e-08
5.44e-06
5.35e-08
6.12e-12
3.00e-06
1.28e-07
5.52e-06
2.02e-06
1.69e-05
5.28e-07
4.10e-07
2.72e-08
6.77e-04
4.99e-08
6.51e-06
6.43e-08
7.32e-12
3.60e-06
1.54e-05
6.62e-06
2.42e-06
2.02e-05
6.34e-07
4.92e-07
3.25e-08
8.09e-04
6.01e-08
2.08e-08
2.05e-10
2.34e-14
1.15e-08
4.89e-08
2.11e-08
7.70e-09
6.44e-08
2.02e-09
1.56e-09
1.04e-10
2.58e-06
1.91e-10
1.19e-08
1.17e-10
1.34e-14
6.54e-09
2.79e-08
1.21e-08
4.42e-09
3.68e-08
1.16e-09
8.92e-10
5.936-11
1.48e-06
1.09e-10
Lifetime Excess Cancer Risk (b)
Arsenic
30-yr exposure
70-yr exposure
3.36e-10
7.84e-10
4.16e-10
9.70e-10
3.89e-10
9.08e-10
4.67e-10
1.09e-10
1.49e-12
3.47e-12
8.52e-13
1.99e-12
(a) Only pollutants for which there is an oral RfD are presented in this summary table.
(b) Only pollutants for which there is a slope factor are presented in this summary table.
5.5.1 Gulf of Mexico
Under the current technology scenario, there are 13 development wells (12 existing and 1
new source) and 7 existing exploratory wells in Gulf of Mexico shallow waters (< 1,000 ft).
Under the discharge option, there are 28 (27 existing and 1 new source) development wells and
15 exploratory wells in Gulf of Mexico shallow waters. The catch impacted in the Gulf of
Mexico is calculated in Exhibit 5-14.
-------
5-20
Exhibit 5-14. Calculation of Shrimp Catch Impacted in the Gulf of Mexico
Number of Wells
Area Impacted (km2)
(1.9km2/well)
Catch Rate (Ibs/mi2) (a)
Total Catch Affected (Ibs)
Total Catch (Ibs)
% of Total Catch Affected
Current Technology
Development
13
24.7
Exploratory
7
13.3
Discharge Option
Development
28
53.2
Exploratory
15
28.5
11,443
65,856
35,461
141,843
75,987
172,474,211
0.038%
0.021%
0.082%
0.044%
(a)
The catch rate calculation is presented in Appendix A.
These percentages of catch affected are used to adjust the intake calculations assuming
that individuals would consume seafood from the entire Gulf harvest and exposure would be
proportional to the amount of the total catch affected. The estimated noncarcinogenic and
carcinogenic risks are presented in Exhibits 5-15 through 5-18 for Gulf of Mexico commercial
shrimp affected by the current technology and the discharge option. Based on the 99th percentile
consumption rate of 177 g/day, the hazard quotients for noncarcinogenic risks and the lifetime
excess cancer risk estimate for carcinogens (arsenic) are well below the acceptable risk levels
adopted by the Agency for this analysis.
5.5.2 Cook Inlet, Alaska
As presented in Section 5.3.2, shrimp harvesting by trawling or pot fishing is prohibited
in Cook Inlet, Alaska by the Alaska Board of Fisheries due to inadequate information regarding
the biology and stock status of shrimp in Cook Inlet waters (Beverage, 1998). Therefore, human
health effects from exposure to commercial shrimp harvests were not analyzed for Cook Inlet,
Alaska SBF-cuttings discharges.
-------
5-21
Exhibit 5-15. Commercial Shrimp Health Risks - Gulf of Mexico, Shallow Water
Development Model Well, Current Technology
Pollutant
(A)
Shrimp Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
9.80e-02
1.93e-03
l.lle-01
3.30e-06
2.70e-03
3.45e-03
1.99e-03
5.44e-04
4.63e-03
4.55e-02
1.48e-03
1.20e-02
9.51e-03
1.84e-03
1.22e-04
4.85e-02
1.35e-02
7.30e+02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
9.42e-08
1.85e-09
1.07e-07
3.17e-12
2.59e-09
3.31e-09
1.91e+09
5.23e-10
4.45e+09
4.37e-08
1.42e-09
1.15e-08
9.14e-09
1.77e-09
1.17e-10
4.66e-08
1.30e-08
7.01e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
4.71e-06
4.64e-08
5.28e-12
2.59e-06
1.10e-05
4.78e-06
1.74e-06
1.46e-05
4.57e-07
3.54e-07
2.34e-08
5.83e-04
4.32e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 3.36e-10
70 yr: 1.50e+00 7.84e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * (0.177 (kg/day) * % of catch affected) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-22
Exhibit 5-16. Commercial Shrimp Health Risks - Gulf of Mexico, Shallow Water
Development Model Well, Discharge Option
Pollutant
(A)
Shrimp Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
5.62e-01
1.10e-03
6.38e-02
1.89e-06
1.54e-03
1.97e-03
1.40e-03
3.12e-04
2.65e-03
2.60e-02
8.46e-04
6.86e-03
5.44e-03
1.05e-03
6.98e-05
2.78e-02
7.71e-03
4.18e+02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
1.17e-06
2.28e-09
1.32e-07
3.92e-12
3.19e-09
4.08e-09
2.36e-09
6.47e-10
5.49e-09
5.39e-08
1.75e-09
1.42e-08
1.13e-08
2.18e-09
1.45e-10
5.76e-08
1.60e-08
8.67e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
5.83e-05
5.70e-08
6.53e-12
3.19e-06
1.36e-05
5.91e-06
2.16e-06
1.80e-05
5.64e-07
4.35e-07
2.89e-08
7.21e-04
5.33e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 4.16e-10
70 yr: 1.50e+00 9.70e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * (0.177 (kg/day) * % of catch affected) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-23
Exhibit 5-17. Commercial Shrimp Health Risks - Gulf of Mexico, Shallow Water
Exploratory Model Well, Current Technology
Pollutant
(A)
Shrimp Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
2.05e-01
4.03e-03
2.33e-01
6.91e-06
5.65e-03
7.23e-03
4.16e-03
1.14e-03
9.71e-03
9.53e-02
3.10e-03
2.51e-02
1.99e-02
3.86e-03
2.56e-04
1.026-01
2.82e-02
1.53e+02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
1.09e-07
2.14e-09
1.24e-07
3.67e-12
3.00e-09
3.84e-09
2.21e-09
6.05e-10
5.16e-09
5.06e-08
1.65e-09
1.33e-08
1.06e-08
2.05e-09
1.36e-10
5.42e-08
1.50e-08
8.12e-05
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.00e-01
NA
7.00e-02
NA
NA
NA
5.44e-06
5.35e-08
6.12e-12
3.00e-06
1.28e-05
5.52e-06
2.02e-06
1.69e-05
5.28e-07
4.10e-07
2.72e-08
6.77e-04
4.99e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 3.89e-10
70 yr: 1.50e+00 9.08e-10
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * (0.177 (kg/day) * % of catch affected) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-24
Exhibit 5-18. Commercial Shrimp Health Risks - Gulf of Mexico, Shallow Water
Exploratory Model Well, Discharge Option
Pollutant
(A)
Fish Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
1.17e-01
2.31e-03
1.33e-01
3.95e-06
3.24e-03
4.14e-03
2.38e-03
6.53e-04
5.56e-03
5.46e-02
1.77e-03
1.44e-02
1.14e-02
2.21e-03
1.46e-04
5.82e-02
1.62e-02
8.76e+02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
1.30e-07
2.57e-09
1.48e-07
4.39e-12
3.60e-09
4.61e-09
2.65e-09
7.27e-10
6.19e-09
6.07e-08
1.97e-09
1.60e-08
1.27e-08
2.46e-09
1.62e-10
6.48e-08
1.80e-08
9.75e-04
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
6.51e-06
6.43e-08
7.32e-12
3.60e-06
1.54e-05
6.62e-06
2.42e-06
2.02e-05
6.34e-07
4.92e-07
3.25e-08
8.09e-04
6.01e-08
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 4.67e-10
70 yr: 1.50e+00 1.09e-09
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * (0.177 (kg/day) * % of catch affected) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-25
5.5.3 Offshore California
EPA projects that there is one shallow water development model well using SBFs in
offshore California. The shrimp catch impacted offshore California is calculated in the following
manner:
impact area per well: 1.9 km2
number of wells: 1 development well
area impacted: 1.9 km2
total catch: 836,1201bs
Ibs caught/mi2: 3.17 lbs/mi2
catch affected: 1.403 Ibs
% catch affected: 0.000168%
This percentage of the catch affected is used to adjust the intake calculations assuming
that individuals would consume seafood harvested from the entire offshore California shrimp
harvesting area and exposure would be proportional to the amount of the total catch affected.
The estimated noncarcinogenic and carcinogenic risks are presented in Exhibits 5-19 and 5-20
for the current technology and discharge option. Although the current practice offshore
California is zero discharge of SBF-cuttings, the current technology analysis based on 11%
retention on cuttings is presented for comparison purposes. Based on the 99th percentile
consumption rate, the hazard quotient for noncarcinogenic risks and the lifetime excess cancer
risk estimate for carcinogens are both well below the acceptable risk levels adopted by the
Agency for this analysis.
-------
5-26
Exhibit 5-19. Commercial Shrimp Health Risks - Offshore California, Shallow Water
Development Model Well, Current Technology
Pollutant
(A)
Shrimp Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
9.80e-02
1.93e-03
l.lle-01
3.30e-06
2.70e-03
3.45e-03
1.90e-03
5.44e-04
4.63e-03
4.55e-02
1.48e-03
1.20e-02
9.51e-03
1.84e-03
1.22e-04
4.85e-02
1.35e-02
7.30e+02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
4.16e-10
8.20e-12
4.72e-10
1.40e-14
1.15e-ll
1.47e-ll
8.45e-12
2.31e-12
1.97e-ll
1.93e-10
6.29e-12
5.10e-ll
4.04e-ll
7.82e-12
5.18e-13
2.06e-10
5.736-11
3.10e-06
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
2.08e-08
2.05e-10
2.34e-14
1.15e-08
4.89e-08
2.11e-08
7.70e-09
6.44e-08
2.02e-09
1.56e-09
1.04e-10
2.58e-06
1.91e-10
O.OOe+00
(F)
(E) Lifetime
Slope Factor Excess
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 1.49e-12
70 yr: 1.50e+00 3.47e-12
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * (0.177 (kg/day) * % of catch affected) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
5-27
Exhibit 5-20. Commercial Shrimp Health Risks - Offshore California, Shallow Water
Development Model Well, Discharge Option
Pollutant
(A)
Shrimp Tissue
Concentration
(mg/kg)
(B)
99th %ile
Intake
(mg/kg-day)
(C)
OralRfD
(mg/kg-day)
(a)
(D)
99th %ile
Hazard
Quotient
(b)
Noncarcinogenic Risks
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
5.62e-02
1.10e-03
6.38e-02
1.89e-06
1.54e-03
1.97e-03
1.14e-03
3.12e-04
2.65e-03
2.60e-02
8.46e-04
6.86e-03
5.44e-03
1.05e-03
6.98e-05
2.78e-02
7.71e-03
4.18e+02
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.39e-10
4.67e-12
2.71e-10
8.03e-15
6.54e-12
8.37e-12
4.84e-12
1.33e-12
1.13e-ll
1.10e-10
3.59e-12
2.916-11
2.31e-ll
4.46e-12
2.97e-13
1. 18e-10
3.286-11
1.78e-06
O.OOe+00
O.OOe+00
O.OOe+00
O.OOe+00
2.00e-02
4.00e-02
NA
6.00e-01
l.OOe-03
3.00e-04
4.00e-04
3.00e-04
NA
3.00e-03
NA
NA
2.00e-02
5.00e-03
5.00e-03
8.00e-05
3.006-01
NA
7.00e-02
NA
NA
NA
1.19e-08
1.17e-10
1.34e-14
6.54e-09
2.79e-08
1.21e-08
4.42e-09
3.68e-08
1.16e-09
8.92e-10
5.936-11
1.48e-06
1.09e-10
O.OOe+00
(F)
(E) Lifetime
Slope Factor Exces
(mg/kg-day)-l Cancer
Risk (c)
Carcinogenic Risk -
Arsenic Only:
30 yr: 1.50e+00 8.52e-12
70 yr: 1.50e+00 1.99e-12
(a) NA indicates that an oral RfD is not available; RfDs are not available for specific SBF compounds.
(b) None of the hazard quotients exceed 1. Therefore, toxic effects are not predicted to occur.
(c) The lifetime excess cancer risks are less than 10"6 and are, therefore, acceptable.
Table Calculations:
B = A * (0.177 (kg/day) * % of catch affected) / 70 kg
D= B/C
F = B * 30 yrs (or 70 yrs) / 70 (lifetime in yrs) * E
-------
6-1
6. TOXICITY
6.1 Introduction
This chapter presents the information that EPA has reviewed concerning the
determination of toxicity to the receiving environment of various synthetic base fluids and the
formulated synthetic-based drilling fluids (SBFs). This information includes data generated for
toxicity requirements imposed on North Sea operators as well as experimental testing conducted
by the oil and gas industry in the United States. Because the synthetic base fluids are water
insoluble and the SBFs do not disperse in water as water-based drilling fluids (WBFs) do, but
rather tend to sink to the bottom with little dispersion, most research has focused on determining
toxicity in the sedimentary phase as opposed to the aqueous phase.
Since 1984, EPA has used an aqueous phase toxicity test to demonstrate compliance with
NPDES permits for the discharge of drilling fluids and drill cuttings. This aqueous phase test
measures toxicity of the suspended paniculate phase (SPP), and is often called the SPP toxicity
test (see "Drilling Fluid Toxicity Test" 40 CFR 435, Subpart A, Appendix 2). SBFs have
routinely been tested using the SPP toxicity test and found to have low toxicity (Candler et al.,
1997). Rabke et al. 1998a, have recently presented data from an interlaboratory variability study
indicating that the SPP toxicity results are highly variable when applied to SBFs, with a
coefficient of variation of 65.1 percent. Variability reportedly depended on such things as
mixing times and the shape and size of the SPP preparation containers. As part of the coastal
effluent guidelines effort, published in December 1996, EPA identified the problems with
applying the SPP toxicity test to SBFs due to the insolubility of the SBFs in water. (EPA, 1996).
North Sea testing protocols require monitoring the toxicity of fluids using a marine algae
(Skeletonema costatum\ a marine copepod (Arcartia tonsa), and a sediment worker (Corophium
volutator orAbra alba). The algae and copepod tests are performed in the aqueous phase,
whereas the sediment worker test uses a sedimentary phase. Again, because the SBFs are
hydrophobic and do not disperse or dissolve in the aqueous phase, the algae and copepod tests
are only considered appropriate for the water soluble fraction of the SBFs, while the sediment
worker test is considered appropriate for the insoluble fraction of the SBFs (Vik et al., 1996a).
As with the aqueous phase algae and copepod tests, the SPP toxicity test mentioned above is only
relevant to the water soluble fraction of the SBFs (Candler et al., 1997).
Both industry and EPA have identified the need for more appropriate toxicity test
methods for assessing the relative toxicities of various SBFs. EPA has recently begun a research
project to determine the toxicity of synthetic and other oleaginous (oily) base fluids, and
-------
6-2
influences of drilling fluid formulation and crude oil contamination on SBF toxicity. Results
from this research are not yet available. Industry has sponsored and continues to sponsor
research to evaluate and develop test procedures, with the goal of identifying an appropriate
toxicity test method for SBFs as measured at the point of discharge. The toxicity data on SBFs
and SBF base fluids that EPA was able to collect is summarized in Exhibit 6-1. The individual
studies are summarized below.
6.2 Summaries of Identified Articles Containing Toxicity Information
The following two papers presented essentially the same data on Ampelisca abdita and
Corophuim volutator. However, Still and Candler (1997) presented additional data not included
by Candler et al., 1997. Therefore, we have included a summary of both papers.
Candler, J., R. Herbert andA.J.J. Leuterman. 1997. Effectiveness of a 10-day ASTM Amphipod
Sediment Test to Screen Drilling Mud Base Fluids for Benthic Toxicity. SPE 37890.
The authors reported the results of a study sponsored by M-I Drilling Fluids. The study
evaluated the use of the ASTM sediment toxicity test method E1367-92 for determining the
toxicity base fluids used for SBFs and OBFs. The base fluids tested were a diesel oil (DO), an
enhanced mineral oil (EMO), linear paraffin (LP), an internal olefin (IO) and a polyalphaolefin
(PAO). The tests were conducted with two marine amphipods, Ampelisca abdita and Corophium
volutator. The tests were conducted in two phases: 1) whole fluid was used to determine the
range of toxicity to A. abdita and 2) base fluid was used in definitive tests to determine 10-day
LC50 values for both test species. Chemical analyses for Total Petroleum Hydrocarbons (TPH)
were used to determine actual exposure concentrations of the highest concentration of each test.
For Phase 1 of the study, the amphipods were exposed to two concentrations (5,000 and
10,000 mg whole fluid/kg dry sediment). Ranking for toxicity, from most toxic to least toxic, at
5000 mg/kg sediment was: DO and EMO (zero percent survival in both tests), PAO (11 %
survival), IO (32% survival), and LP (44% survival). Rankings at the 10,000 mg/kg sediment
level, from most to least toxic, was: DO and EMO (O% survival), LP (8% survival), PAO (11%
survival), and IO (25% survival). For Phase 2, the amphipods were exposed to definitive
concentrations of a DO, EMO, IO and PAO. The toxicity ranking of the SBFs and OBFs were
based on 10-day LC50 values. Those LC50 values, presented in decreasing toxicity (increasing
LC50 values) for A. abdita tests were: EMO with an LC50 value of 557 mg/kg of sediment, DO
with an LC50 value of 879 mg/kg, IO with an LC50 value of 3,121 mg/kg, and PAO with an
LC50 value of 10,690 mg/kg. The LC50 values for C. volutator were: DO (840 g/kg), EMO
(7,146 mg/kg), IO (>30,000 mg/kg), and PAO (>30,000 mg/kg). The authors stated that the
study proved that the ASTM E1367-92 test methods and both of the test species can be used as
screening tool for use with synthetic base fluids.
-------
Exhibit 6-1. Reported Toxicities of Synthetic-Based Fluids (LCSOs)
Ampelisca
abdita
Leptocheirus
plumulosus
Rhepoxynius
abronius
Corophium
volutator
/l/»ra a//»a
Skeletonema
costatum
Acartia
tonsa
Fundulus
grandis
BASE FLUID - Natural Sediment
Diesel
Candler, 1997
Rabke, 1998b
Still, 1997
EMO
Candler, 1997
Still, 1997
IO
Candler, 1997
Rabke, 1998b
Vik, 1996
Still, 1997
PAO
Candler, 1997
Rabke, 1998b
Vik, 1996
Still, 1997
Ester
Vik, 1996a
Acetal
Vik, 1996a
LAO
Vik, 1996a
879 mg/kg
1.0 ml/kg
0.7 ml/kg
557 mg/kg
3 121 mg/kg
4.0 ml/kg
3.0 ml/kg
10,690 mg/kg
13. 4 ml/kg
12.5 ml/kg
850 mg/kg
251 mg/kg
3. 7 ml/kg
2,944 mg/kg
9,636 mg/kg
24 mg/kg
239 mg/kg
299 mg/kg
975 mg/kg
840 mg/kg
7 146 mg/kg
>30,000mg/kg
7,100mg/l
>30,000mg/kg
12.0 ml/kg
3.0 ml/kg
300 mg/1
7,900 mg/1
>100,000 mg/1
549 mg/1
1,021 mg/1
2,050 mg/1
3,900 mg/1
60,000 mg/1
>100,000 mg/1
>10,000 mg/1
>10,000 mg/1
>50,000 mg/1
50,000 mg/1
>100,000 mg/1
>10,000 mg/1
BASE FLUID - Formulated Sediment
Diesel
Rabke, 1998b
1.0 ml/kg
0.7 ml/kg
-------
Exhibit 6-1. Reported Toxicities of Synthetic-Based Fluids (LCSOs; continued)
Ampelisca
abdita
Leptocheirus
plumulosus
Rhepoxynius
abronius
Corophium
volutator
/l/»ra a//»a
Skeletonema
costatum
Acartia
tonsa
Fundulus
grandis
WHOLE FLUID - Natural Sediment
Diesel
Rabke, 1998b
IO
Rabke, 1998b
Friedheimetal.,
1996
PAO
Rabke, 1998
Jones, 1991
Friedheimetal.,
1996
Vik, 1996a
Ester
Vik, 1996a
LAO
Friedheimetal.,
1996
1.5 ml/kg
1.5 ml/kg
3. 7 ml/kg
9.4 ml/kg
2.3 ml/kg
36.5 ml/kg
7,131 mg/kg
>10,000 mg/kg
>10,000 mg/1
1,268 mg/kg
303 mg/kg
572 mg/kg
7,000 mg/1
277 mg/kg
82,400 mg/1
>50,000 mg/1
34,000-
145,000 mg/1
>8.4% TPH
>50,000 mg/1
WHOLE FLUID - Formulated Sediment
Diesel
Rabke, 1998b
IO
Rabke, 1998b
Hood, 1997
3. 6 ml/kg
2.9 ml/kg
1.7 ml/kg
0.7 ml/kg
1.3 ml/kg
2.5 ml/kg
2.7 ml/kg
10.5 ml/kg
2,279 mg/kg
4,498 mg/kg
2,245 mg/kg
1,200 mg/kg
943 mg/kg
-------
Exhibit 6-1. Reported Toxicities of Synthetic-Based Fluids (LCSOs; continued)
PAO
Rabke, 1998b
Ampelisca
abdita
Leptocheirus
plumulosus
<2.5 ml/kg
Rhepoxynius
abronius
Corophium
volutator
Abra alba
Skeletonema
costatum
Acartia
tonsa
Fundulus
grandis
WHOLE FLUID -No Sediment
IO
Rabke, 1998a
Hood, 1997
Mysidopsis bahia
221,436 - >1,000,000 ppm
(SPP)
56,500 - >1,000,000 ppm
(SSP)
-------
6-6
Still, Land J. Candler. 1997. Benthic Toxicity Testing of Oil-Based and Synthetic-Based
Drilling Fluids. Eighth International Symposium on Toxicity Assessment. Perth, Western
Australia. 25-30May 1997.
A two phase sediment toxicity study was conducted to examine the applicability of
established sediment toxicity test methods for synthetic base fluids and SBFs. During Phase I,
the marine amphipod Ampelisca abdita was tested with one drilling fluid formulation dosed
individually with the following five base fluids: a diesel oil (DO), an enhanced mineral oil
(EMO), a linear paraffin (LP), an internal olefin (IO) and a polyalphaolefm (PAO). Testing
during Phase I served as rangefinders, with test concentrations of 5,000 and 10,000 mg drilling
fluid/kg dry sediment. Enhanced mineral oil and diesel were the most toxic for both
concentrations. The toxicity ranking (most toxic to least toxic) for the SBFs at 5,000 mg/kg were
PAO, IO and LP. The toxicity ranking (most toxic to least toxic) for the SBFs at 10,000 mg/kg
were LP, PAO, and IO. For Phase n, definitive sediment toxicity tests were conducted. LC50
values were determined for EMO, DO, IO and PAO base fluids, using four marine amphipods:
Ampelisca abdita, Corophium volutator, Rhepoxynius abronius, and Leptocheirusplumulosus.
Tor Ampelisca abdita, the toxicity ranking (most toxic to least toxic) and corresponding LC50
values were: EMO (557 mg/kg); DO (879 mg/kg); IO (3,121 mg/kg); and PAO (10,680 mg/kg).
For Corophium volutator, the toxicity ranking (most toxic to least toxic) and corresponding
LC50 values were: DO (840 mg/kg); EMO (7,146 mg/kg); IO (>30,000 mg/kg); and PAO
(>30,000 mg/kg). For Rhepoxynius abronius the toxicity ranking (most toxic to least toxic) and
corresponding LC50 values were: DO (24 mg/kg); EMO (239 mg/kg); IO (299 mg/kg); and PAO
(975 mg/kg). For Leptocheirusplumulosus, the toxicity ranking (most toxic to least toxic) and
corresponding LC50 values were: EMO (251 mg/kg); DO (850 mg/kg); IO (2,944 mg/kg); and
PAO (9,636 mg/kg). These results were ranked against the UK Offshore Chemical Notification
Scheme (OCNS), which includes sediment testing as well as biodegradation and bioaccumulation
in the ranking procedure. Using the OCNS classification, the results of this study ranked the
based fluids, from most toxic to least toxic, as: diesel, enhanced mineral oil, IO and PAO.
Rabke S. et al. 1998a. Interlaboratory Comparison of a 96-hour Mysidopsis bahia Bioassay
Using a Water Insoluble Synthetic-Based Drilling Fluid. Presented at 19th Annual Meeting
of Society of Environmental Toxicology and Chemistry. Charlotte, NC 1998.
The authors conducted an interlaboratory variability study with six different laboratories
using the SPP toxicity test with a synthetic-based drilling fluid (SBF). The purpose was to
determine the variability associated with this test method when applied to SBFs. A subsample of
an internal olefin SBF was shipped to the individual laboratories where the SPP test was
conducted. Results were reported in ppm (vol:vol) of SPP and ranged from 221,436 to
>1,000,000 ppm. The coefficient of variation was 65.1 %.
-------
6-7
Rabke, S. andJ. Candler. 1998b. Development of Acute Benthic Toxicity Testing for Monitoring
Synthetic-Based Muds Discharged Offshore. Presented at IBC Conference on Minimizing
the Environmental Effects of Offshore Drilling, Houston Texas, February 9, 1998.
The authors used the ASTM E1367-92 method to determine the toxicity of synthetic-based
drilling fluids (SBFs) and oil-based drilling fluids (OBFs) to the marine amphipods Ampelisca
abdita and Leptocheirus plumulosus. The authors examined the variability of the test, including
variability due to test organisms. The authors used formulated sediments in place of natural
sediments to evaluate their use in marine sediment testing. However, concurrent tests were
conducted using natural sediment as a control. The test species were exposed to varying
concentrations of diesel oil (DO), polyalphaolefm (PAO) and internal olefm (IO). The authors
concluded that using formulated sediments and whole fluids decreased the usefulness of the test
method as a screening tool; PAO synthetic-based drilling fluids appeared to be as toxic as diesel
in the whole fluid/formulated sediment test; and formulated sediment gave acceptable control
survival although it reduced the discriminatory power of the tests. The results of the study are
presented in Exhibit 6-1.
Jones, F. V., J.H. Rushing andM.A. Churan. 1991. The Chronic Toxicity of Mineral Oil-Wet
and Synthetic-Wet Cuttings on an Estuarine Fish, Fundulus grandis. SPE 23497.
The authors determined the toxic effects of cuttings associated with a mineral oil-based
drilling fluid (OBF-cuttings) and a poly alpha oelfin (PAO) synthetic-based drilling fluid (PAO-
SBF-cuttings) to an estuarine fish, the mud minnow, Fundulus grandis. Unaltered cuttings were
dried and crumbled to a uniform state and divided in half. The cuttings were then hot rolled with
the appropriate amounts of each drilling fluid to obtain concentrations of 1%, 5%, and 8.4% oil
on wet cuttings, based on retort measurements. Before distributing the fish in test containers, the
fish were anesthetized with 2.5 ppt quinaldine, then measured for weight and length. The fish
were allowed to recover in fresh seawater before placement in test containers. Contaminated
cuttings were layered (approximately 3.8 cm thick) into tanks, then covered with seawater. Each
tank received seawater flow at a rate of 28.5 ml/2 minute intervals. The fish were exposed for a
total of 30 days. Fish were randomly removed from each tank on Day 15 for length and weight
measurements. The authors also sacrificed the fish for bioaccumulation measurements; no data
were provided in this paper. (However, see Chapter 7 for a discussion of Rushing et al., 1991, a
companion paper containing procedural details.) At Day 30 the remaining fish were measured
for weight and length. The authors concluded that neither the mineral oil-based nor synthetic-
based drilling fluids affected growth of the fish based on percentage growth. However, the
overall growth of the control and 5% PAO-SBF cuttings-exposed fish at Day 15 and Day 30 were
significantly greater than fish exposed to all other treatments.
-------
6-8
Vik, E.A., S. Dempsey, B. Nesgard. 1996a. Evaluation of Available Test Results from
Environmental Studies of Synthetic Based Drilling Muds. OLF Project, Acceptance
Criteria for Drilling Fluids. Aquateam Report No. 96-010.
The authors provided a summary for tests conducted with unused base fluids and whole
SBFs. However, the authors did not cite sources for the data, leaving one to assume the work
was conducted by their laboratory. The authors state that the North Sea test organisms were a
marine algae {Skeletonema costatum\ a marine copepod (Acartia tonsa\ and a sediment worker
(Corophium volutator, orAbra alba). The authors consider that algae and copepods are relevant
for the water soluble fraction tests and sediment workers are relevant for testing the non-soluble
fraction. The authors further state that the algae has been the most sensitive of three species in
controlling the toxicity of discharged fluids.
Montgomery, R. 1998. Memorandum to J. Daly, EPA, Regarding Draft API Sediment Toxicity
Protocol for Use With Synthetic-Based Drilling Fluids. December 11, 1998. Plus
attachments.
Work for this report is in progress, therefore detailed data will not be presented here.
However, there are trends that appear worth reporting. API is sponsoring a research study to
evaluate the appropriateness of sediment toxicity tests with Leptocheirusplumulosus, Ampelisca
abdita, and Mysidopsis bahia as applied to SBFs and OBFs. The API research is also evaluating
the MICROTOX test. Phase 1 of the study compared rangefmding results with whole fluids
mixed in formulated sediments. Trends indicated sediment toxicity of the synthetic-based fluids
did not differ much (i.e., by a factor of <2X) when compared to sediment toxicity of an OBF
based on diesel oil. Phase 2 was conducted with the same species and whole fluids mixed in
natural sediments. The trend was that sediment toxicity of the SBFs was slightly less (i.e., by a
factor of 2-3X) when compared to sediment toxicity of OBFs. Another trend is the loss of
discriminatory power between sediment toxicity of OBFs and SBFs. Results of the tests with
natural sediments appeared to have better discriminatory power over the results of tests with
formulated sediments. Both industry and EPA are currently investigating methods to
discriminate sediment toxicity of SBFs and OBFs.
Hood,C. 1997. Unpublished Data Received By J.Daly (U.S. EPA) July 9,1997 from
C. Hood, Baker Hughes INTEQ.
Unpublished data was provided by Ms. Cheryl Hood of Baker Hughes INTEQ, on the
toxicity of four synthetic-based drilling fluids (SBFs) to the mysid, Mysidopsis bahia and the
amphipod, Leptocheirus plumulosus. The 96-h LC50 for the mysids ranged from 14,600 to
>500,000 ppm SPP and the 10-d LC50 for the amphipod ranged from 943 to 4498 mg SBF/kg
dry sediment.
-------
6-9
6.3 Summary
Although there are data available on the toxicity of both SBFs and base fluids from the
North Sea and United States, the information is insufficient to draw meaningful conclusions
other than broad generalizations. Also, little is known about the influence of the organics in
either natural sediments or formulated sediments on the toxicity of these fluids. However, with
the limited data, several assumptions can be made.
(1) North Sea amphipods appear to be less sensitive to synthetic base fluids than those
amphipods currently used in US testing.
(2) Synthetic base fluid toxicity appears to show greater discriminatory power versus diesel
toxicity than does SBFs toxicity.
(3) Discriminatory power seems to be diminished with the use of formulated sediments.
(4) Mysid SPP testing does not appear to be a relevant test method for these fluids.
Because data are limited, EPA and industry are continuing to gather information on
sediment toxicity through ongoing research. Industry is currently evaluating sediment test
methods, using formulated sediments and species sensitivities. EPA is beginning research on the
toxicity of synthetic base fluids and the factors that influence the toxicity of these synthetic base
fluids (as well as the biodegradation and bioaccumulation of synthetic base fluids). The goal of
EPA research is to restore discriminatory power to discern the differences in toxicity between
diesel oil, mineral oil, and synthetic base fluids. Because the current, examined amphipod test
species are not indicating sufficient discriminatory power, EPA may further consider using other
test organisms, such as polychaetes.
-------
7-1
7. BIOACCUMULATION
7.1 Introduction
One factor to be considered in assessing the potential environmental impacts of discharged
drilling fluids and drill cuttings is their potential for bioaccumulation. This chapter presents the
information that EPA has gathered concerning the bioaccumulation of oleaginous base fluids,
including the synthetic base fluids and mineral oil.
The information that EPA identified was provided by oil and gas operators and by oilfield
chemical (drilling mud) suppliers. Much of this information is in the public domain. However,
only a minimal amount can be found in peer reviewed publications. Most of the available
information has been developed by mud suppliers to provide information to government
regulators to assess the acceptability of these materials for discharge into the marine
environment.
7.2 Summary of Data
The available information on the bioaccumulation potential of synthetic base fluids is
scant, comprising only a few studies on octanol:water partition coefficients (Pow) and two on
tissue uptake in experimental exposures [only one of which derived a bioconcentration factor
(BCF)]. The Pow represents the ratio of a material that dissolves or disperses in octanol (the oil
phase) versus water. The Pow generally increases as a molecule becomes less polar (more
hydrocarbon-like). The available information on the bioaccumulation potential of synthetic base
fluids covers only three types of synthetics: an ester (one studies), internal olefms (IO; three
studies), and poly alpha olefms (PAO; four studies). One study included a low toxicity mineral
oil (LTMO) for comparative purposes. This limitation with respect to the types of synthetic base
fluids tested is partially mitigated by the fact that these materials represent the more common of
synthetic base fluid types currently in use in drilling operations.
These limited data suggest that synthetic base fluids do not pose a serious bioaccumulation
potential. Despite this general conclusion, existing data cannot be considered sufficiently
extensive to be conclusive. This caution is specifically appropriate given the wide variety of
chemical characteristics resulting from marketing different formulations of synthetic fluids (i.e.,
carbon chain length or degree of unsaturation within a fluid type, or mixtures of different fluid
types). Additional data should be obtained both for the purpose of confirming what is known
about existing fluids and to ensure completeness and currency with new product development.
-------
7-2
The data that EPA identified concerning the bioaccumulation potential of synthetic base
fluids are summarized in Exhibit 7-1. Nine reports provided original information. This
information consisted of Pow data (based on calculated or experimental data), dispersibility data,
or subchronic exposure of test organisms to yield data for calculating BCFs or assessing uptake.
log Pow values less than three or greater than seven would indicate that a test material is not likely
to bioaccumulate (Zavallos et al., 1996).
For PAOs, the log Pows reported were >10, 11.9, 14.9, 15.4, and 15.7 in the four studies
reviewed. The three studies of lOs that were reviewed reported log Pows of 8.57 and >9. The
ester was reported to have a log Pow of 1.69 in the one report in which it was tested. A log Pow of
15.4 was reported for an LTMO. The only BCF reported was calculated for lOs; a value of
5.4 I/kg was determined. In 30-day exposures of mud minnows (Fundulus grandis) to water
equilibrated with a PAO- or LTMO-coated cuttings, only the LTMO was reported to produce
adverse effects and tissue uptake/occurrence. Growth retardation was observed for the LTMO
and LTMO was observed at detectable levels in 50% of the muscle tissue samples examined (12
of 24) and most (19 of 24) of the gut samples examined. The PAO was not found at detectable
levels in any of the muscle tissue samples and occurred in only one of twenty-four gut samples
examined.
7.3 Summaries of Identified Reports Containing Bioaccumulation Information
Friedheim, J.E. et al. 1991. An Environmentally Superior Replacement for Mineral-Oil Drilling
Fluids. SPE 23062. Presented at the Offshore Europe Conference, Aberdeen, September
3-6, 1991.
Bioaccumulation studies were conducted on both the PAO-base fluid and the PAO-based
SBF. The calculated octanol/water partition coefficient for the PAO gives a log Pow of 15.4. The
authors concluded the PAO was not expected to bioaccumulate in aquatic species for a variety of
reasons. The authors base their projection on data that indicate gill uptake of xenobiotics
increases with increasing lipophilicity up to about a log Pow of 7, beyond which there exists an
inverse relationship between lipophilicity and bioconcentration. Thus, these authors believe that
there appears to be a cut-off point in water solubility (or lack thereof) beyond which compounds
cannot move past the aqueous diffusion layer present at the water/gill interface; a similar scenario
accounts for a decreased absorption of hydrophobic chemicals in fish intestine. Therefore,
Friedheim et al. concluded the physico-chemical properties of the PAO (i.e., low water
solubility) would prohibit it from passing freely into aquatic species and bioaccumulating. PAOs
are highly lipid soluble, and thus Friedheim et al. believe they are likely to be absorbed into the
organic fraction of the sediment or onto suspended organic solids in the aquatic environment.
These authors postulate that the PAO either would not be bioavailable (due to
-------
7-3
Exhibit 7-1. Bioaccumulation Data for Synthetic Fluids and Mineral Oil Muds
Type of Synthetic
Base Fluid or
LTMO
PAO
PAO
PAO
PAO
10
10
Ester
LTMO
various
IO
PAO
LTMO
PAO
LTMO
Parameter Determined
log Pow: 15.4 (calculated)
log Pow: >10 (calculated)
logPow: 14.9 - 15.7 (measured)
logPow: 11.9 (measured)
logPow:>9
log Pow: 8.57
log Pow: 1.69
log Pow: 15.4
dispersibility: ranking =
ester> di-ether » detergent alkylate > PAO >
LTMO
10-day uptake; 20-day depuration exposure gave
logBCF: 5.37 (C16 forms); 5.38 (CIS forms)
Uptake: no measured uptake in tissues after 30-day
exposure; presence noted in 1 of 24 gut samples
Uptake: after 30-day exposure, detectable amounts
in 50% of tissues analyzed (12 of 24) and 19 of 24
gut samples examined
Subchronic effects: equal or better growth vs
controls
Subchronic effects: retarded growth vs controls
Reference
Friedheimetal., 1991
Leutermann, 1991
Schaanning, 1995
Zevallos et al., 1996
Environment & Resource
Technology, Ltd., 1994a
Zevallos et al., 1996
Growcock et al., 1994
Growcock et al., 1994
Growcock et al., 1994
Environment & Resource
Technology, Ltd., 1994b
Rushing etal., 1991
Rushing etal., 1991
Jones etal., 1991
Jones etal., 1991
Abbreviations: PAO: poly alpha olefin; IO: internal olefin; LTMO: low toxicity mineral oil
sequestration by the sediment) or would not be able to pass through the gill (or intestine) due to
the molecular size of the "suspended particle," (which is likely referring to the adsorption of the
PAO to the suspended organic solids to which the authors referred earlier).
-------
7-4
Leuterman, A.J.J. 1991. Environmental Considerations in M-I Product Development
Novasol/Novadril. M-IDrilling Fluids Co., January 15, 1991.
Although Novasol [a PAO] is highly lipid soluble, with a calculated octanol/water partition
coefficient (log P) of >10.0, it was not expected by this author to bioaccumulate in aquatic
species. Leuterman presented several reasons he considered well-documented. These reasons
include the following:
1. High molecular weight, low water soluble polymers are thought not to pass biological
membranes due to molecular volume considerations.
2. Highly lipophilic chemicals in aquatic systems are likely to absorb and partition into the
organic fraction, in this case the organic fractions of the drilling fluid. In this arrangement
the chemical constituent would not be bioavailable for absorption due to sequestration in
the drilling fluid and cuttings or would not be able to pass through the gill or intestine, if
ingested, due to the molecular size of the chemical constituent.
3. Gill uptake of xenobiotics increases with increasing lipophilicity up to about log P of 7.
Beyond this level there exists an inverse relationship between lipophilicity and
bioconcentration. Toxicokinetically this reduction apparently results from a decrease in the
magnitude of the uptake rate constant. There appears to exist a cut-off point in the water
solubility, i.e., the lack of, beyond which compounds cannot move past an aqueous
diffusion layer present at the water/gill interface. A similar scenario accounts for decreased
absorption of hydrophobic chemicals in fish intestines. Since transport into biological
membranes requires, in most cases, that the xenobiotic be available in a dissolved form, the
physico-chemical properties of Novasol, i.e., low water solubility, would prevent its
passage into aquatic species and thence bioaccumulate.
4. If the base fluid did pass into the aquatic species, aquatic animals have the ability to
metabolize xenobiotics through various enzyme systems located primarily in the intestine
and liver. Once metabolized, these metabolites are normally of a more water soluble form,
i.e., hydroxylated products, and are eliminated from the organism and not accumulated.
To confirm the expected low bioavailability of Novasol, M-I conducted a thirty (30) day
bioaccumulation test using the mud minnow Fundulus grandis. This author states that
preliminary results of this test reveal no detectable amount of the material, or its degradation
products, in the tissue or organs of the test animals. In fact, the test animals showed no ill effect,
no deformities and no reduced growth rates. No data are provided, however.
-------
7-5
Friedheim, J.E. and KM. Panternuehl. 1993. Superior Performance With Minimal
Environmental Impact: A Novel Nonaqueous Drilling Fluid. SPE/IADC 25753. presented
at the SPE/IADC Drilling Conference, Amsterdam, February 23-25, 1993.
Both an octanol/water partition coefficient determination and actual laboratory testing with
fish were discussed to describe the potential for bioaccumulation of the PAO system. The
authors cite earlier reports (Friedheim et al. 1991), in which the partition coefficient (log Pow) for
the PAO is 15.4. This high value along with the large molecular weight of the material led the
authors to conclude the PAO should not accumulate in aquatic life. These arguments are based
on knowledge of gill uptake of xenobiotics and absorption of hydrophobic chemicals in intestines
offish. The authors' conclusion is that the physico-chemical properties of the PAO would
prohibit it from passing freely into aquatic species and bioaccumulating. Also, previous
laboratory bioaccumulation test results (Rushing et al., 1991) using Fundulus grandis (mud
minnow) were cited to support the arguments presented above.
Schaanning, M. T. 1995a. Evaluation of Overall Marine Impact of the NovadrilMud Systems.
NIVA Report 0-95018.
The ICI Brixham Laboratory estimated that log Pow = 14.9-15.7 for a PAO product coded
AB-5243-SO. This product was, however, composed of 65% of a synthetic hydrocarbon having
a chain length of 22 carbon atoms (C22), 20% C32, and 15% C42 and C52 oligomers, neither of
which were predominant components of the Novasol I and Novasol n base fluids. Measured
coefficients of polyalphaolefms (oligomer composition not specified) exceeded the upper limit of
8.0 that could be determined by the applied HPLC-method.
Information on concentrations of Novasol PAO's in animal tissues from exposed
organisms, as noted by these authors, is rather scarce. The authors discuss a few results of a
recent study offish sampled at a North Sea Novadril n well site that were cited in M-I
information dated January, 1995. No taste or smell was found in any of the fish sampled.
Neither did the concentration of Novasol exceed the detection limit of 0.1 mg.kg-1 in any of the
fish samples analyzed. No information was provided by the authors as to where, when and how
sampling was performed or how many and which species were analyzed. The authors also
present that analyses of commercial fish species captured at the drilling sites is obviously of great
public interest. Because of the lack of control on exposure of the analyzed individuals to the test
chemical, however, a field study showing neither smell, taste nor detectable concentrations, was
not considered to yield evidence that the chemical has a low potential for bioaccumulation.
Results of Rushing et al. (1991) were also discussed in this report.
-------
7-6
Growcock, F.B., S.L. Andrews and T.P. Frederick. 1994. Physicochemical Properties of
Synthetic Drilling Fluids. IADC/SPE 2 7450. Presented at the IADC/SPE Drilling
Conference, Dallas, Texas, February 15-18, 1994.
The dispersibility (aqueous phase partitioning) of synthetic fluids in seawater was tested.
The dispersibility test consists of shaking equal volumes of seawater and synthetic fluid for 10
seconds followed by a 10 minute equilibration prior to sampling the seawater phase for organic
carbon analysis. The test gave the following trend among various synthetic base fluids:
Ester>Di-Ether»DetergentAlkylate>PAO>LTMO.
This trend was considered by the authors as qualitatively consistent with the trend in the
octanol/water partition coefficient, Pow, which ranges from log Pow =1.69 for the ester to log Pow
= 15.4 for the PAO and the LTMO (no data or sources cited). The authors concluded that it is
possible for a significant portion of the ester, and perhaps other synthetics as well, to disperse in
seawater.
Fcerevik, I. Undated. Discharges and regulations of synthetic drilling fluids on the Norwegian
Continental Shelf and summary of results from ecotoxicological testing and field surveys.
Norwegian Pollution Control Authority.
Laboratory testing shows that many of the chemicals in synthetic drilling fluids have a
potential for bioaccumulation. Specifically the olefin base fluids show log Pow values well above
7.0. The ester base fluids are unlikely to bioaccumulate, but several of the additives in ester
based drilling fluids show log Pow values above 5.0. The molecular weight for both base fluids
and additives in synthetic drilling fluids are typically below 600.
The author asserts that existing bioaccumulation tests are not relevant for surface active
substances that are commonly present in synthetic drilling fluids. Rather, bioaccumulation
should be expressed as the distribution between sediment and water (the sedimentwater partition
coefficient, log Psw), not as now by the octanol and water coefficient (log Pow). The author states
that the potential for bioaccumulation is overestimated due to inadequate methods of calculation.
Because these fluids have such low aqueous solubilities, a concern has been noted that Pow
data are less relevant than, perhaps, Psw data. This would provide some measure of the potential
for long-term leaching of these materials into sediment pore water with their subsequent
availability to benthic infauna and epifauna. This concern is valid, and these data may be worth
pursuing because the standard Pow and Psw protocols appear adequate to evaluate these fluids and
are relatively brief and inexpensive procedures. Also, standard experimental protocols for
-------
7-7
measuring uptake in test species are available and would be useful for testing a subset of
materials for which log Pow or Psw determinations have been performed to confirm
bioaccumulation potentials projected from Pow or Psw data.
Environment & Resource Technology. 1994a. Bioaccumulation Potential oflSO-TEQ Base
Fluid. ERT 94/209. Prepared for Baker Hughes INTEQ.
The bioaccumulation potential of ISO-TEQ base fluid, an internal olefm of chain length
from 16 to 18 carbon atoms (C16-C18), was evaluated. The bioaccumulation potential was
estimated by measuring the log octanol-water partition coefficient by HPLC following OECD
117 guidelines. Under the standard conditions described in the report, no elution of the test
substance occurred during a period of 6.5 hours. To enhance the elution of the test substance, it
was re-examined using 2-propanol: water. The absence of detectable HPLC peaks with the
standard system indicated that the log Pow value for ISO-TEQ base fluid was greater than the
value for the most lipophilic calibration standard, suggesting that the value would be greater
than 9.
Environment & Resource Technology. 1994b. Bioconcentration Assessment Report, Assessment
of the bioconcentration factor (BCF) of ISO-TEQ base fluid in the blue mussel Mytilus
edulis. ERT 94/061. Prepared for Baker Hughes INTEQ.
The study was conducted in accordance with an SOP written to conform with OECD
guidelines 305 A-E for the determination of bioconcentration or bioaccumulation of chemicals
from the aqueous phase. Specimens of the blue mussel Mytilus edulis were exposed to saturated
aqueous concentrations of ISO-TEQ base fluid ( a predominantly C16-C18 internal olefm) under
flow-through conditions for ten days, and subsequently allowed to depurate in clean seawater for
a further 20 days. BCF values were calculated from uptake and depuration rates or each
compound group separately. The bioconcentration factors (BCF) were calculated from
the ratio of tissue (lipid) concentration to water concentration of the major components of
the fluid at equilibrium (10 days), or if a steady-state was not achieved,
• the ratio of the uptake to depuration rate constants, calculated as defined in the SOP.
The test met all validity criteria, with the exception of exposure concentration control,
which varied more than specified as a consequence of the very low saturation concentrations of
the test substance components. The variation was not, however, of a magnitude sufficient to
significantly affect the estimated low BCF values. ISO-TEQ exhibited high rates of uptake and
depuration, with no detectable tissue residue. The equilibrium log BCF values (lipid weight
basis) for the test substances were estimated to be 5.37 for the C16 compounds and 5.38 for the
-------
7-8
CIS compounds. After cessation of exposure, the test animals depurated their tissues to
concentrations of test compound to < 1 ug.g-1 (0.03% of peak value). Log BCF values were
approximately half the probable log Pow values (>8).
Jones, F. V., Rushing, J.H., andM.A. Churan. 1991. The Chronic Toxicity of Mineral Oil-Wet
and Synthetic Liquid-Wet Cuttings on andEstuarine Fish, Fundulus grandis. SPE 23497.
Presented at the First International Conference on Health, Safety and Environment, The
Hague, The Netherlands, November 10-14, 1991.
Mud minnows (Fundulus grandis) were held in tanks of synthetic seawater (i.e.,
formulated from a mixture of salts and substances that mimic natural seawater). Drilling fluids
were prepared using a 80/20 ratio of mineral oil/water for a 7.4 pounds per gallon (ppg) drilling
fluid (MOBF) and a 70/30 ratio of PAO/water for an 11.0 ppg drilling fluid (PAO-SBF). Both
drilling fluids were then hot-rolled for 16 hours at 66°C. Each drilling fluid was added to a
container of dried cuttings, hand-mixed, and hot-rolled for another 24 hours at 66°C. Laboratory
bioaccumulation tests showed that the presence of cuttings soaked in an 11.0 ppg 70/30 PAO-
SBF system did not affect the growth rate of this species. Rather, they showed equal or better
weight gain and size increase as compared to the control samples. Conversely, test runs using
MOBF-soaked cuttings showed a retarded growth rate with respect to the control. The authors
also offered that fish cultured with the mineral oil had to spend a large portion of their energy
removing this hydrocarbon from their blood stream, and that this energy drain may have caused
the lower observed growth in those fish in the MOBF tanks.
Zevallos, M.A., J. Candler, J.H. Wood and L.M. Reuter. 1996. Synthetic-Based Fluids Enhance
Environmental and Drilling Performance in Deepwater Locations. SPE 35329. Presented
at the SPE International Petroleum Conference & Exhibition of Mexico, Villahermosa,
Tabasco, Mexico, March 5-7, 1996.
Measurement of bioaccumulation of synthetic fluids can be estimated using the N-
octanol/water partition coefficient (Pow). Pow values less than three or greater than seven would
indicate that the test material will not bioaccumulate. Both the 11.19 Pow for PAO and 8.57 Pow
for IO indicate these synthetic materials would not bioaccumulate. Ranked by their Pow values,
lOs have a greater potential than PAOs to bioaccumulate.
-------
7-9
Davies, J.M., D.R. Bedborough, R.A.A. Blackman, J.M. Addy, J.F. Appelbee, W.C. Grogan, J.G.
Parker and A. Whitehead. 1989. The Environmental Effect of Oil-based Mud Drilling in
the North Sea. In: Drilling Wastes, F.R. Engelhardt, J.P Ray andA.H. Gillam (eds).
Elsevier Applied Science, New York. Pp. 59-89
During 1985 and 1986, fish were caught from three areas in the North Sea close to oil and
gas exploration and production platforms and from areas outside the influence of drilling activity
as reference (control) samples. These operations had drilled many wells using OEM, including
both diesel oil- and mineral oil-based OEMs. Fish were tasted by a trained panel to determine
the presence of any oily taint in the flesh. A fish was deemed to be oil tainted if more than half
the panel detected an oily taint. Among cod, haddock, tusk, and dabs caught between 0.40 and
9.3 km from oil platforms, only for dabs caught between 0.55 km and 0.86 km did more than half
the panel detect an oily taint.
Rushing, J.H., M.A. Churan, andF.V. Jones. 1991. Bioaccumulation from Mineral Oil-Wet and
Synthetic Liquid-Wet Cuttings in an Estuarine Fish, Fundulus grandis. SPE 23497.
Presented at the First International Conference on Health, Safety and Environment, The
Hague, The Netherlands, November 10-14, 1991.
The authors report an experimental study on uptake of low aromatic mineral oil (LTMO)
and Novasol PAO in tissue and gut samples from mud minnows (Fundulus grandis) exposed for
30 days to water equilibrated with contaminated cuttings at nominal concentrations of 1%, 5%,
and 8.4% base fluid (i.e., PAO or mineral oil). Gut samples represented carefully excised
internal organs and connecting structures from the mouth to the anus. Muscle tissue samples
were prepared from fish whose heads, tails, skin, and viscera were removed, thus including finer
bones in these samples. Samples from each of the three dosings were taken seven times during
the course of the exposure (Days 3, 7, 10, 15, 20, 25, and 30) and again after a 4-day depuration
period.
Among fish exposed to SBM-coated cuttings, analysis offish tissue and organs using
GC/MS measured no uptake of PAO in samples offish tissue, and an accumulation of PAO was
observed in only one of 24 gut samples. By contrast, fish exposed to LTMO cuttings showed
accumulations of mineral oil in 19 of 24 fish gut samples and detectable amounts of mineral oil
components in 12 of the 24 tissue samples analyzed. Both mineral oil and olefms were shown
present in the water of the aquaria throughout the exposure period.
The authors concluded that the contrast between the mineral oil and the polyalphaolefms
was a result of restricted uptake of the larger olefm molecules across gill and digestive structures.
The authors further assert that the high molecular weight and the structure of PAOs is a key
factor in limiting the amount of uptake by fish. Since PAOs are a complex, high molecular
-------
7-10
weight molecule, fish could not uptake the material through its gill structure. One sampling
showed a low amount of PAO in the gut analysis. It is possible this material was in the intestinal
tract of the fish and had not passed through the fish when sampled.
-------
8-1
8. BIODEGRADATION
8.1 Introduction
A number of different and contrasting test methods have been used to predict the
biodegradability of synthetic base fluids deposited on offshore marine sediments. These method
variations have included: calculation of biochemical oxygen demand in inoculated freshwater
aqueous media versus uninoculated seawater aqueous media; determination of product (gases)
evolved versus the concentration of synthetic base fluid remaining at periodic test intervals;
varying initial concentrations of test material; aqueous versus sediment matrices; and within
sediment matrices, layering versus mixed sediment protocols.
In the field, the mechanisms observed from the deposition of SBF contaminated drill
cuttings involve the initial smothering of the benthic community followed by organic enrichment
of the sediment due to adherent drilling fluids. Organic enrichment causes oxygen depletion due
to the biodegradation of the discharged synthetic base fluids. This biodegradation results in
predominantly anoxic conditions in the sediment, with limited aerobic degradation processes
occurring at the sediment: water column interface. Therefore, the biodegradation of deposited
drilling fluid will be an anaerobic process to a large degree. Standardized tests that utilize
aqueous media, while readily available and easily performed, may not adequately mimic the
environment in which the released synthetic base fluid is likely to be found and degraded. As a
result, alternative test methods have been developed that more closely simulate seabed
conditions. One method uses a deposition of synthetic base fluid on marine sediment and
measuring degradation in a sediment matrix. Another method uses anaerobic conditions in
aqueous media (Vik et al., 1996b; Limia, 1996; Munro, 1997).
8.2 Biodegradation Test Methods
A variety of test methods, each with characteristic limitations and qualifications, has been
used to assess the biodegradation of test materials. Slater et al. (1995) present a descriptive
comparison of the technical details of the Organization for Economic Co-operation and
Development (OECD) 301-series test protocols, the Biochemical Oxygen Demand for Insoluble
Substance (BODIS) protocols, and seabed simulation test protocols.
The OECD 301-series tests are all aqueous freshwater tests that use an activated sewage
sludge inoculum. As an example of 301 protocols, the OECD 301D "Clean Bottle" test protocol
is briefly summarized in Exhibit 8-1. The 301A through 301F tests vary in the analytical
endpoint used to quantify oxygen demand, the concentration range of the test substance, and their
-------
8-2
design suitability among poorly soluble, volatile, or adsorbing test substances. The drawbacks of
using these tests for synthetic base fluids are: the insolubility of synthetic base fluids in aqueous
media, the use of a freshwater matrix, the use of an aqueous matrix for the test, and the aerobic
nature of the test.
Exhibit 8-1. OECD 301D: 28-Day Closed Bottle Test
A solution of test substance (e.g., synthetic base fluid) is prepared in a mineral medium consisting
of stock solutions of a) KH2PO4, K2HPO4, Na^PO^HjO, NH4C1; b) CaCl2; c) MgSO4-7H2O; and
d) FeCl3-6H2O. The test solution is poured into test bottles and inoculated with a small number of
micro-organisms derived from the secondary effluent of a domestic sewage treatment plant (or
laboratory-scale unit) or surface water. A parallel series of bottles containing inoculated blank
medium is prepared for reference measurements of oxygen uptake by the inoculum. The closed
test bottles are incubated in the dark at constant temperature for 28 days. Dissolved oxygen
measurements are taken via Winkler titration or oxygen electrode at time zero and weekly
intervals; more frequent intervals require more bottles. The percent degradation of the test
substance is calculated as the ratio of the biochemical oxygen demand of the test substance (in mg
O2 uptake per mg test substance) and the theoretical oxygen demand (or less accurately, the
chemical oxygen demand) of the test substance.
The OECD 306 methods change the matrix from a freshwater matrix to a seawater matrix,
and allow for two analytical variants. In one analytical variant, the incubation period increases
from 28 days to 60 days. The biggest difference between the OECD freshwater and seawater
tests is the presence of an activated sludge inoculum in freshwater tests versus the absence of an
inoculum in the seawater tests, which relies on endogenous marine microorganisms for
degradative capacity.
Two International Standards Organization (ISO) protocols, one for freshwater
(BODIS/FW) and one for seawater (BODIS/SW), also have been used to assess biodegradability
of insoluble test materials. The same characteristics as discussed for the OECD 301 methods
regarding the presence/absence of a sludge inoculum apply to these ISO protocols: the freshwater
test uses inoculum but the seawater test does not. Likewise, freshwater and seawater
respirometric methods, which rely on analytically different endpoints, can be characterized as
similar to the 301-series tests. An ISO protocol for assessing freshwater anaerobic
biodegradability is available (see Exhibit 8-2 for a brief description). The protocol may more
accurately assess real-world conditions for a large portion of discharged synthetic base fluids.
However, although this protocol provides a quantification of anaerobic biodegradation, it still
relies on an aqueous freshwater matrix.
-------
8-3
Exhibit 8-2. ISO 11734: "Water Quality-Evaluation of the "Ultimate" Anaerobic
Biodegradability of Organic Compounds in Digested Sludge—Method by
Measurement of the Biogas Production"
A test compound (e.g., synthetic base fluid) is added to a dilution medium at an organic
carbon concentration of 20 mg/1 to 100 mg/1. The dilution medium is a solution of the following
constituents: KH2PO4, Na2HPO4-12H2O, NH4C1, CaCl2-2H2O, MgCl2-6H2O, FeCl2-4H2O,
Na2S-9H2O, resazurin (oxygen indicator), stock solution of trace elements, and de-oxygenated
water. Under anaerobic conditions, the test solution is inoculated with washed digested sludge
containing very low amounts of inorganic carbon, then incubated in sealed vessels in the dark at
constant temperature for 60 days.
As a result of anaerobic degradation, carbon dioxide and methane evolve in the headspace
above the test solution, and the amount of dissolved carbon dioxide, hydrogen carbonate, or
carbonate in the solution increases. The amount of microbiologically produced carbon in the head
space gas is calculated from the measured increase in head space pressure as applied to the gas law
equation (PV=nRT). The amount of inorganic carbon produced in the solution is measured, and is
added to the amount of head space carbon to determine the total carbon produced in excess over
blank values. The percentage biodegradation is calculated as the total carbon produced relative to
the initial carbon in the test compound.
The progress of biodegradation can be charted by intermediate measurements of head
space pressure. A graph of pressure versus time should show an initial lag phase followed by a
period of steadily increasing pressure, ending with a plateau phase indicating the cessation of gas
production. Significant deviations from this course may indicate that the test should be prolonged
or repeated.
To address the issue of aqueous versus sediment matrices, two non-standard test protocols
have been developed. One, the "NIVA" protocol (Norwegian Institute for Water Research;
Schaanning, 1994), which is commonly referred to as the "simulated seabed study," relies on
layering of test material on the surface of the test sediment. The other is the "SOAEFD" test
protocol (Scottish Office, Agriculture Environment and Fisheries Department; Munro et al.,
1997b), which is commonly referred to as the "solid phase test," mixes the test material into the
test sediment prior to incubation (see Exhibits 8-3 and 8-4 for brief descriptions of the NIVA and
SOAEFD protocols). These laboratory protocols, to date, have assessed biodegradability of
synthetic fluids at experimental sediment levels (NIVA = 700 mg/kg to 18,000 mg/kg; SOAEFD
= 100 mg/kg to 5,400 mg/kg) that are below or at the lower end of the range of sediment
concentrations of synthetic fluids measured in the field at two drill sites in the North Sea (up to
4,700 mg/kg and up to 100,000 mg/kg) and one drill site in the Gulf of Mexico (up to 134,000
mg/kg, or 13.4 percent).
-------
8-4
Exhibit 8-3. NIVA Protocol for Simulated Seabed Biodegradation Study
NIVA protocols have evolved since 1990, and intend to more accurately represent offshore seabed
conditions for biodegradation. The test consists of a series of chambers containing clean sediment, covered
with 15 cm of seawater drawn from a depth of 60 m from the Oslofjord and pumped through the experimental
chambers. On Day 0, a thin layer of drill cuttings (1-2 mm) is created by adding a slurry to the chamber water
and allowing particulates and solids to settle. Tests run for as long as 160 days.
Based on the measured amounts of fluid at Day 0 and the last day of the test, the percentage decrease
is calculated. Rates are adjusted for the loss of drilling fluid due to seawater flow by using Ba concentrations
as an indicator for test substance lost due to seawater flow-through. NIVA has found that first-order kinetics
describe the loss of drilling fluid over time according to
Ct = C0 x 10*
where Ct =test substance concentration at time / (in days), C0 = the concentration at / = 0, k is the decay
constant, and / is the time in days.
Exhibit 8-4. SOAEFD Protocol for Solid-Phase Test System for Degradation of
Synthetic Base Fluid
A synthetic base fluid is homogeneously mixed at specific concentrations with prepared marine
sediment and maintained in a trough of flowing sea water for 120 days. Base fluid is added at concentrations of
100 ppm, 500 ppm, and 5,000 ppmto represent historical measurements of mineral-oil-based cuttings piles at
distances from the platform of 1,000 m to 3,000 m, 200 m to 1,000 m, and 200 m, respectively. The
concentrations of added base fluid are determined empirically prior to the experiment as ug TOC per g of dry
sediment.
At set times, triplicate jars are removed for chemical analysis of the base fluid. The concentration of
the base fluid remaining is determined by solvent extraction followed by gas chromatography with flame
ionization detection. Base fluid concentrations (in ppm) are graphed as a function of time; results are compared
in terms of how closely the data follow first order reaction kinetics, as expressed by the equation:
At — A0e
where A0 is the concentration of the substance at time t = 0, At is the concentration at time t, k is the rate
constant for the reaction and e is the log to the base e.
Three additional analyses are conducted to further characterize the course of biological activity
throughout the experiment: the oxidation-reduction (redox) profiles of the test sediments as compared with
clean sediment; the number of culturable bacteria from sediments; and the number of bacteria capable of growth
on the test fluid as the sole carbon source (the Sheen-screen). The sediment redox profiles, expressed in mV,
measure the level of oxygenation of the sediment at varying depths, indicating the local concentration of
organic matter. Trends in redox measurements are charted by depth and over time, for temporal and spacial
comparisons between test sediments and clean sediment. Throughout the experiment, samples are taken at the
sediment surface and at a depth of 4 mm to measure the number of "culturable" aerobic and anaerobic bacteria.
The Sheen-screen measures the number of aerobic and facultative anaerobic bacteria per gram of wet sediment
capable of growth on the synthetic base fluid as the sole carbon source. It is an indicator for the biodegradation
potential of a base fluid in the sediment used. The conditions for the Sheen-screen are aerobic and thus, growth
of obligate anaerobes is not provided for and test conditions do not accurately mimic real world conditions for
discharged synthetic drilling fluids.
-------
8-5
Aerobic test conditions have been summarized by Vik et al. (1996b) and are presented in
Exhibit 8-5; a summary of laboratory and field biodegradation assessment procedures were
summarized by Vik at al. (1996b) and are presented in Exhibit 8-6.
8.3 Biodegradability Results
Two overarching concerns in any presentation of data on biodegradation of synthetic base
fluids are the incompatibility of test results obtained using different protocols and the high
variability routinely encountered within a given protocol. These two factors mitigate against the
utility of the data in any comparative sense. Additionally, the differences in fresh- versus
saltwater media, aerobic versus anaerobic media, and aqueous versus sediment matrices render
the applicability of most of the reported tests as extremely limited. Sedimentary phase tests are
more comparable to the actual conditions in which these materials will be found and provide
more consistent results than aqueous phase tests.
8.3.1 Aqueous Phase Tests
Exhibit 8-7 presents a ranking of aerobic biodegradation test results for an acetal synthetic
fluid using OECD 301B (FW), 301D (FW), 306 (SW), BODIS (FW), and BODIS (SW)
protocols at two concentrations of added test material. Given the substantial differences in
experimental design and protocols, results of 28-day tests expectantly show a wide range in
results, from 5% degradation to 86% degradation. Degradation was, as expected for a system
subject to saturation kinetics, more extensive for any given protocol at the lower test
concentrations (although with one exception). Few other comparisons are meaningful. For
example, seawater tests show less degradation than freshwater tests. Thus, BODIS seawater tests
show less degradation (8% and 19.5% at 40 mg/1 and 10 mg/1, respectively) than BODIS
freshwater tests (50% and 86% at 40 mg/1 and 10 mg/1, respectively). Similarly, the OECD 306
seawater test at all concentrations shows less degradation compared to either the OECD 301B or
301D freshwater tests at the same test concentration. However, the freshwater tests all use an
activated sewage sludge inoculum of microorganisms, whereas the seawater tests are endogenous
levels of microorganisms, with no exogenous addition of microbial degraders. Because the
initial degradative capacity of the two types of media are not comparable, no valid quantitative
comparisons are possible.
Within laboratory variability also is high for these tests. Exhibit 8-8 presents BODIS
aerobic freshwater and seawater results at one laboratory for two synthetic fluids (an ester and an
acetal). The pooled, average relative standard deviation (RSD) for four freshwater tests of each
-------
8-6
Exhibit 8-5. Summary of Aquatic Phase Aerobic Laboratory Biodegradation Test
Conditions and Their Suitability for Poorly Soluble, Volatile, and Surface Active
Compounds
OECD
Guidelines/
ISO Procedures (a)
OECD 301 A -DOC
Die-Away
OECD 301B - CO2
Evolution Test
OECD 30 1C -
MTTI (1) Test
OECD301D-
Closed Bottle Test
OECD 30 IE -
Modified OECD
Screening Test
OECD 30 IF -
Manometric
Respirometry Test
OECD 308 -
Biodegradability in
seawater
- Shake Flask Test
- Closed Bottle Test
ISO-procedure:
BOD-test for
insoluble substances
(BODIS)
Modified Seawater
BODIS Test
Respirometric
methods
Analytical
Method
Dissolved
organic carbon
(DOC)
CO2 evolution
Oxygen
consumption
Dissolved
oxygen
Dissolved
organic carbon
Oxygen
consumption
Dissolved
organic carbon
Dissolved
oxygen
Dissolved
oxygen
Dissolved
oxygen
Respirometric:
CO2-
production
02-
consumption
in headspace
Suitability for compounds which
are:
Poorly
Soluble (b)
-
+
+
+/-
-
-
-
-
+
Volatile
-
-
+/-
+
-
+,
-
-
-
Adsor-
bing (b)
+/-
+
+
+
+,
-
+,
+,
+/-
Concen-
tration of
Test
Substance
10-40 mg
DOC/1
10-20 mg
DOC/1
100 mg/1
2-5 mg/1
10-40 mg
DOC/1
50-100
mg
ThOD/1
5-40 mg
DOC/1
2-10 mg/1
lOOmg
ThOD/1
(c)
lOOmg
ThOD/1
(c)
lOOmg
ThOD/1
(and
lower) (c)
Ino-
culum
+
+
+
+
+
-
-
-
-
Test
Duration
(days)
28
28
28
28
28
28
60
28
28
28
Test
Medium
FW
FW
FW
FW
FW
FW
SW
FW
SW
SW/FW
Abbreviations: ThOD = Theoretical oxygen demand; BOD = biochemical oxygen demand
(c) OECD (1993); ISO (1990)
(d) Characteristics of synthetic base fluids
(e) Corresponds to ~ 30 mg/1 test substance of drilling fluids
Source: Viketal., 1996b
-------
Exhibit 8-6. Summary of Test Procedures Used in the Biodegradation Testing of Synthetic-Based Drilling Fluids
Factors
influencing test
results
Test Substance
Physical test
conditions:
Temperature °C
Availability of
oxygen
Nutrient
availability
Test concentration
Depth of mud layer
Migration of test
substance
Inoculum:
Quantity/density
Variability
Acclimation
Source
Renewal
Aqueous Phase Tests
Aerobic
Seawater
(a)
Base fluid or
Synthetic
Fluid
15-20
Good
Good
2-40 mg/1
Not
applicable
Not
applicable
Low
High
None
Seawater
None
Fresh-
water
Base fluid or
Synthetic
Fluid
15-25
Good
Good
0.5-40 mg/1
Not
applicable
Not
applicable
Generally
high
Lower than
seawater
None
Activated
sludge
None
Anaerobic
Fresh-water
Base fluid or
Synthetic
Fluid
37
None
Good
50 mg/1
Not
applicable
Not
applicable
High
Lower than
seawater
None
Activated
sludge
None
Sedimentary Phase Studies
NIVA "Seabed
Simulation"
Cuttings
7-12
Lower dependent on
test concentration
May be limiting
700-1 8000 mg/kg
1-2 mm
Possible
Fairly low
High
Some
Seawater and mixed
sediments (b)
Possible
SOAEFD "Solid
Phase"
Base fluid
7-12
Very low
May be limiting
100, 500, 5000
mg/kg
Mixed into the
sediment
Very low
Fairly low
High
Some
Seawater and
mixed sediments
Possible
Seabed Surveys
Norwegian
sector
Cuttings
7-12
Very low
May be limiting
up to 100,000
mg/kg
0-20+ cm
Very probable
Fairly low
High
Some
Seawater and
natural benthic
fauna
Very likely
Dutch sector
Cuttings
7-12
Very low
May be limiting
up to 4700 mg/kg
0-20+ cm
Extensive
Fairly low
High
Some
Seawater and
natural benthic
fauna
Very likely
Gulf of Mexico
Cuttings
7-12
Very low
May be limiting
up to 134,000
mg/kg
0-20+ cm
Extensive
Fairly low
High
Some
Seawater and
natural benthic
fauna
Very likely
-------
Exhibit 8-6. Summary of Test Procedures Used in the Biodegradation Testing of Synthetic-Based Drilling Fluids (continued)
Factors
influencing test
results
Test Substance
Sampling/analyses :
Sampling depth
Chemical analyses
Macrofaunal
analyses
Microbial analyses
Relevance of test to
real environment
Aqueous Phase Tests
Aerobic
Seawater
(a)
Base fluid or
Synthetic
Fluid
Not relevant
Oxygen
demand/CO2
None
No
Aerobic
degradation
only
Fresh-
water
Base fluid or
Synthetic
Fluid
Not relevant
Oxygen
demand/CO2
None
No
Not relevant
Anaerobic
Fresh-water
Base fluid or
Synthetic
Fluid
Not relevant
CO2
None
No
Not relevant
Sedimentary Phase Studies
NIVA "Seabed
Simulation"
Cuttings
1-2 cm
Presence of base
fluid/DO/pH/redox
Mortality on surface
(d)
Yes
Relevant, but test
concentrations are
lower; question
anaerobic condition
simulation and test
substance migration
SOAEFD "Solid
Phase"
Base fluid
8.6 cm (c)
Presence of base
fluid/DO/redox
None
Yes
Relevant; dosing
more stable but
misses layering
as in situ
Seabed Surveys
Norwegian
sector
Cuttings
1 cm
Presence of base
fluid
Abundance and
diversity
Relevant.
Difficult to
obtain
representative
samples and
compatible
results from one
year to another
Dutch sector
Cuttings
10cm
Presence of base
fluid
Abundance and
diversity
Relevant.
Difficult to
obtain
representative
samples and
compatible
results from one
year to another
Gulf of Mexico
Cuttings
up to 1 m
Presence of base
fluid
Abundance and
diversity
Relevant.
Difficult to
obtain
representative
samples and
compatible
results from one
year to another
(a) No standard marine test presently exists and a large variety of methods have been used.
(b) In the latest NIVA test, natural benthic fauna were sieved out, then returned.
(c) NIVA are presently trying an alternative procedure using undisturbed sediments to keep the macro-fauna alive.
(d) Comprises the entire test container contents.
DO = dissolved oxygen
Adapted from Vik et al., 1996b
-------
8-9
Exhibit 8-7. Ranking of Aqueous Phase Biodegradation Methods and Test Results
No.
1
2
4
5
6
3
7
8
9
10
11
Test Method
BODIS Freshwater
OECD 301 B Freshwater
OECD 301 B Freshwater
BODIS Freshwater
OECD 306 Seawater
OECD 301 D Freshwater
OECD 301 D Freshwater
BODIS Seawater
OECD 306 Seawater
BODIS Seawater
OECD 306 Seawater
Test Concentration
10 mg/1
10mg/l
20 mg/1
40 mg/1
0.5 mg/1
0.5 mg/1
2.5 mg/1
10 mg/1
10 mg/1
40 mg/1
2 - 2.5 mg/1
% Biodegradation
86
78.6
62.8
50
35
73
21
19.5
9.4
8
5
Source: Slater et al. (1995)
Exhibit 8-8. Average Percentage Biodegradation Using BODIS Seawater and Freshwater
Procedures for an Ester and Acetal
Base
fluid
Ester
Acetal
Seawater tests
Test#
(a)
1
2
3
4
5
6
Pooled
average
1
2
3
4
5
6
Pooled
average
Biodeg.
41
32
29
34
57
59
42
9
5
9
11
37
12
14
s.d.
(b)
8.1
2.9
7.1
3.7
5.2
5.0
12.9
2.2
1.2
1.8
2.8
4.7
7.1
11.2
Relative
s.d. (%)
(c)
18
9
24
11
9
8
31
24
24
20
25
13
59
80
n
5
5
5
5
5
5
30
5
5
5
5
5
5
30
Freshwater tests
Test#
(a)
1
2
3
4
Pooled
average
1
2
3
4
Pooled
average
Biodeg.
68
94
94
99
92
58
69
75
95
79
s.d.
(b°)
3.1
11.2
9.9
1.9
12.9
10.7
9.1
12.0
4.9
16.5
Relative
s.d. (%)
(c)
5
12
11
2
14
18
13
16
5
21
n
4
4
7
10
25
4
5
7
10
26
(a) # = number of parallels
(b) s.d. = standard deviation
(c) relative s.d. = defined as (s.d./biodeg) x 100%
Source: Viketal. (1996b)
-------
8-10
base fluid was 14% for the ester (n=25) and 21% for the acetal (n=26). For six seawater tests,
however, the RSD increased to 31% (n=30) and 80% (n=30), respectively for the ester and acetal.
Anaerobic results, although more relevant to the potential impacts of synthetic base fluids
in marine receiving waters, show even greater variability for many types of synthetic base fluids
(Exhibit 8-9). For example, fatty acid esters or alcohols showed significant anaerobic
degradation potential, with degradation ranging from 79% to 89% with RSDs of less than 25%.
However, degradation rates ranged from -1.5% to 48% for 13 mineral oils and 8 other synthetic
fluids. Furthermore, RSDs were much higher, with a minimum RSD of 80% and all others well
in excess of 100%.
8.3.2 Sedimentary Phase Tests
Schaanning (1994; 1995; 1996a; and 1996b) reported on a series of studies using the NIVA
methods (Exhibit 8-3) to compare the biodegradation rates (half-life) of ester, IO, LO,PAO and
ether base and based fluids. The results from the studies indicated the following degradation
rates esters>LO>IO>PAO>ethers. The half-lifes reported were esters ranged from 16 to 22 days,
LO half-life reported was 51 days, IO half-life reported was 73 days, PAO ranged from 43 to 207
days, and the ethers ranged from 254 to 536 days.
Vik et al. (1996b) compare the results of two sedimentary phase protocols (NIVA and
SOAEFD) for ester-type synthetic fluids (Exhibit 8-10). An ester-type synthetic base fluid was
degraded 46% and 97% at 28 days and 160 days, respectively, in the NIVA protocol, with a
calculated half-life of 31 days. The SOAEFD protocol for a similar synthetic base fluid resulted
in 97% degradation at 28 days with no further measured degradation at 60 days, giving a
calculated half-life of 12 days. Experimental differences, as discussed earlier, are substantial
enough that any comparison is not very meaningful. Vik et al. (1996b) also report results of the
NIVA protocol (see Exhibit 8-10) across a variety of synthetic fluids and mineral oil. Their
results indicate the ester and LAO fluids (respective half-lives of 31 and 43 days) degrade more
rapidly than the PAO, acetal, and mineral oil (half-lives ranging from 199 - 207 days). This
general trend was also observed in the solid phase tests, at least for the lower test concentrations.
Limia (1997) reports solid phase degradation data for a series of test substances that
included an ester, acetal, PAO, IO, LAO, n-paraffin, and mineral oil. Results suggested relative
degradation rates were dependent on initial concentrations. At the highest concentration (5,000
-------
8-11
Exhibit 8-9. Anaerobic Biodegradability of Test Chemicals Examined in the ECETOC
Screening Test (a)
Test Chemical
fatty acid ester I
fatty acid ester II
Oleyl alcohol
2-Ethyl hexanol
Mineral oil A
Mineral oil B
Mineral oil C
Di-octyl ether
Di-hexadecyl ether
linear «-olefin (C16/18)
linear «-olefin (C14)
Polyalphaolefin I
Polyalphaolefin II
Alkylbenzene
Acetal-derivative
Test
Duration
(days)
35
35
84
84
35
28
28
42
42
84
98
70
50
50
70
Degradation in the ECETOC test (% of organic carbon)
Net gas
Production
63.3
61.2
61.1
57.3
0.7
4.3
3.8
8.8
-0.6
22.3
40.5
4.4
-1.6
0.9
3.7
Net DIC (b)
Production
19.2
22.5
27.5
21.5
3.2
1.1
2.0
3.5
1.9
0.1
7.8
10.0
2.2
-2.4
8.9
Extent of Ultimate
Degradation (c)
82.5±13.9
83.7±13.1
88.6±14.8
78.8±21.4
3.9±11.0
5.4±8.2
5.8±6.7
12.3±10.8
1.4±12.5
22.4±19.5
48.3±15.5
14.4±20.3
0.6±16.2
-1.5±12.2
12.6±19.2
(a) ECETOC = European Centre for Ecotoxicology and Toxicology of Chemicals
(b) DIC = Dissolved Inorganic Carbon
(c) Value reported is mean value (from 5 replicates) and its 95%-confidence interval
Source: Steberetal. (1995)
mg/kg) the ester, LAO, and acetal all showed substantial degradation (25 - 50%;
ester>acetal>LAO) after 120 days, whereas all other base fluids tested showed little degradation.
At 500 mg/kg, degradation of the ester was nearly 60%, whereas all of the other base fluids
degraded much less. At 100 mg/kg, only the ester, LAO, IO, and n-paraffin all degraded
substantially (>75%), whereas the other test materials (mineral oil, PAO, and acetal) did not
show more than 35% degradation. Similarly, Munro et al. (1998) reported degradation rates
using the SOAEFD method that were highly concentration dependent as well as sediment
dependent. The half-life for all compounds tested (olive oil, mineral oil, ester, and PAO-LAO
blend) increased with concentration and from mud to sand.
-------
8-12
Exhibit 8-10. Percentage Biodegradation of Base Fluids in Drilling Fluids Measured by
Various Test Methods
Drilling
Fluid/Base
Fluid Tested
An ester
A mineral oil
APAO
An acetal
AnIO
An LAO
AnLO
An ether
% Biodegradation Measured by Sedimentary Phase Test Methods
NIVA's Seabed Simulation Studies
(layered using drilling fluid)
160-day
97
44
43
39
93
28-day
46
23
11
12
38
Half-life (days)
(a)
16, 20, 22
399
43, 127, 207
200
73
43
51
254, 392, 536
SOAEDF's Solid-Phase Sediment Test
(base fluid/sand mixture)
60-day
67b, 97C, 98 (d)
98, 78, 25 (e)
16, 10, -4 (e)
-11,4, 8 (e)
20, 0, 10 (e)
60, 10, -2 (e)
70, 23, 5 (e)
28-day
97
Half-life
(days)
37 (b), 12 (c),
10 (d)
(a) Values from Schaanning (1994, 1995, 1996a & 1996b)
(b) Mixed in mud substrate; Munro et al. (1997)
(c) Substrate not specified in Vik et al. (1996)
(d) Mixed in sand substrate; Munro et al. (1997)
(e) Three values presented are day 56 values at 100 mg/kg, 500 mg/kg, and 5,000 mg/kg sediment substrates,
respectively; Munro et al. (1997)
Source: Adapted from Vik et al. (1996b)
8.4 Discussion and Conclusions
The result of this review is that the current state of knowledge for these materials is as
follows:
All synthetic fluids have high theoretical oxygen demands (ThODs) and are likely to
produce a substantial sediment oxygen demand when discharged in the amounts typical of
offshore drilling operations.
Existing aqueous phase laboratory test protocols are incomparable and results are highly
variable. Sedimentary phase tests are less variable in their results, although experimental
differences between the "simulated seabed" and "solid phase" protocols have resulted in
variations between test results.
-------
8-13
• There is disagreement among the scientific community as to whether slow or rapid
degradation of synthetic base fluids is preferable with respect to limiting environmental
damage and hastening recovery of benthic communities. Materials which biodegrade
quickly will deplete oxygen more rapidly than more slowly degrading materials. However,
rapid biodegradation also reduces the exposure period of aquatic organisms to materials
which may bioaccumulate or have toxic effects.
• Limited field data suggest these materials will be substantially degraded on a time scale of
one to a few years; however, the distribution and fate of these materials is not extensively
documented, especially as applicable to the Gulf of Mexico where only three field studies
have been conducted.
The limited data from field studies suggest that organic enrichment of the sediment will be
a dominant impact of SBF-cuttings discharges. Biodegradability of these materials is therefore
an important factor in assessing their potential environmental fate and effects.
Available standard methods yield results that are highly variable across available
freshwater and seawater protocols. These methods (all aqueous, most freshwater, and all but one
aerobic) also are not very relevant to the conditions under which discharged materials will be
found (i.e., a largely anoxic, marine sediment matrix). Nonetheless, one could try to identify
tests that, despite these shortcomings, still could offer useful insight into the potential fate of
these materials. Unfortunately, field data for which potential correlations could be examined are
too scant for meaningful quantitative analyses to these standard laboratory methods.
Seabed simulation protocols and solid-phase tests have been developed to better represent
receiving water conditions. Still, the issue of layering versus sediment mixture of test substances
cannot be resolved absent better field data of actual initial deposition and longer term sediment
depth profiles of these materials in discharged cuttings. It seems likely the real world situation is
a mixture of the two.
Each of the existing biodegradation test methods has advantages and disadvantages. The
seabed simulations better represent field conditions, but they are expensive and have limited
market availability. The standard aqueous test methods are not relevant to field conditions, but
are more rapid, more widely available, and less expensive. The solid phase test combines the
benefits of these two extremes: it mimics receiving water (sediment) conditions, is reproducible,
and can be made simplistic enough to perform at moderate expense.
-------
9-1
9. SEABED SURVEYS
9.1 Background
This chapter presents a summary of the seabed surveys conducted at sites where cuttings
contaminated with SBFs (SBF-cuttings) have been discharged. Because more surveys have been
performed and more detailed information has been collected at sites where WBFs (exclusively)
have been discharged, results from WBF sites are also presented for comparison. The technical
performance of SBFs is comparable to that of OBFs, and EPA is projecting that SBFs may be
used as a replacement to OBFs more so than as a replacement of WBFs. However, as far as
environmental effects of the discharge are concerned, EPA believes that SBFs are more
comparable to WBFs. Also, WBFs are currently allowed for discharge in certain offshore and
coastal areas, while OBFs (and OBF-cuttings) are not. For these reasons, EPA sees it fitting to
compare the environmental effects of SBF-cuttings discharge with those of WBF and WBF-
cuttings discharge.
The literature available to EPA for SBF discharge sites include studies performed in the
Gulf of Mexico and in the North Sea. These studies have been performed both by regulatory
bodies and/or industry groups. The results are available in the open literature. For WBF
discharge sites, EPA used the Offshore Proposed Effluent Guidelines Regulatory Impact
Analysis (Technical Support Document Vol. IE; Avanti Corporation, 1993) as a source of
information on field studies. This volume contains extensive lists of case studies on
environmental impacts from oil and gas effluent discharges. Many of these studies were
reviewed for information regarding seafloor and benthic impacts of water-based fluids and
associated cuttings. In addition to this volume, additional citation searches for studies of the
impacts of cuttings also were performed.
Materially, SBF wastes are different from WBF wastes in at least three important ways:
Only SBF-cuttings are discharged, with retention of the SBF base fluid generally ranging
between a low of 2 percent for the larger cuttings and a high of 20 percent for the smallest
cuttings (fines). On the contrary, with WBFs, in addition to the WBF-cuttings, large
volumes of WBF are also discharged. Thus, for an equal volume of hole drilled, the
volume of WBF-related discharge is expected to be much greater than the volume of
SBF-related discharge.
• WBFs contain very high levels of suspended and settleable solids (and are, in fact,
referred to as "muds" in the industry) that disperse in the water column and produce a
plume with many fine particles that settle rather slowly. Hence, they may be transported
-------
9-2
large distances. SBF-cuttings, however, tend not to disperse in the water column nearly
to the same extent as WBFs because the particles are "oil" wet with the synthetic
material. Even compared to WBF-cuttings, SBF-cuttings tend to be larger than WBF-
cuttings. Again the reason is that SBFs do not disperse the cuttings particles to the same
extent as WBFs. Because larger particles settle faster than smaller particles, SBF-cuttings
tend to be deposited in a smaller impact area than WBF-cuttings.
SBF-cuttings have a significant organic component that is not present in WBFs, namely
the synthetic base fluid. The synthetic base fluid, in general, is insoluble in water and
deposits in the sediment with the cuttings. Thus, compared to WBFs, SBFs have an
additional major pollutant factor. The synthetic base fluid may have both direct and
indirect adverse effects. Direct effects include physical effects as well as chemical toxic
effects to benthic or epibenthic organisms. Indirect effects include both the effects on
organisms that feed on these benthic organisms and the effects of anoxic/hypoxic
sediment conditions from degradation of synthetic base fluids (due to their oxygen
demand in local sediment).
These differences are important in making the comparison between SBF and WBF
discharges, as is presented in the following sections.
9.2 Assessment of Field Studies
9.2.1 Findings
A large number of field studies of environmental impacts of exploratory well drilling
discharges1 in several offshore locations provide sufficient information to arrive at reasonably
reliable findings for WBF seabed impacts. In contrast, existing data for SBFs are limited and do
not appear to be sufficient to reliably project potential impacts. The different SBF studies used
sampling designs that are incompatible and have methodological limitations (e.g., seasonal
variability issues) that reduce the analytic clarity. Further field research is required to adequately
characterize offshore impacts of synthetic-based fluid discharges.
Water-Based Fluids
The case studies reviewed by EPA characterize drilling fluids and cuttings dispersion,
sedimentation, impacts on the sediment and benthos, and some of the potential factors
influencing the magnitude of impacts. Exhibit 9-1 summarizes the major impacts of each of the
reviewed studies. This review suggests that these discharges are capable of producing localized
Studies of development operations are much more limited in both number and scope (e.g., there are no pre-
versus post-drilling surveys). Therefore, conclusions of impacts for WBFs are considerably more
uncertain for development drilling than for exploratory drilling.
-------
9-3
Exhibit 9-1. Marine Studies of Water-Based Drilling Fluid Impacts
Study Source
Menzie et al.,
1980; Mariani et
al., 1980
Houghton et al.,
1980; Lees and
Houghton, 1980
Ray and Meek,
1980; Meek and
Ray, 1980
Zingula, 1975
US DOI, 1977
CSA, 1986
Boothe and
Presley, 1989
Study Site/
Location
NJ 18-3
Block 684
Mid-Atlantic
Continental Shelf
Cook Inlet
C.O.S.T. well
Alaska
Continental Shelf
Tanner Bank
California
Continental Shelf
South Timbalier
Block 172
Louisiana
Continental Shelf
Mustang Island
Block 792
Texas
Continental Shelf
East Breaks Area
Block 166
Gulf of Mexico
Northwest Gulf
of Mexico
Water
Depth (m)
120
62
63
33.5
36
76 - 160
30m;
100m
Impacts (a)
Sediment
* 21 fold increase in Ba at
1.6km
* 3.6 fold increase in Pb at
200m
* 2.5 fold increase in Ni at
100m
* 4 fold increase in Vn at
100m
* increased percentages of clay
size particles within 1.6 km
* cuttings piles observed
* cuttings (1.34 mm dia.) and
20% increase in sediment Ba
cone. 400 m north of platform;
* no piles
* most cuttings fell within 50
m, fine cuttings within 100 m -
200 m of the discharge source;
* mud on cuttings washed off
during settling;
* no piles
* below discharge point:
cuttings covered by normal
marine sediments 8.5 months
after drilling cessation
* cuttings observed at four 100
m and one 500 m station
* 2.5 fold increase in Ba during
drilling at 1,000m
* 7.5 fold increase in Ba and
60% increase in Cr at 4 km
* 2 fold increase in % Fe at
500m
* Ba increase within 500 m;
2.3-11 fold for all 6 sites
* Pb increase within 500 m;
3. 8 fold for 1 site
* Hg increase within 250 m;
4-7 fold for 2 sites
Biota
* within 150 m:
1. burial of sessile mega-
benthos and
macrobenthos;
2. lowest values of species
diversity;
3. lower numbers of
species
* Ba increase in tissue at
1.6km:
mollusks: 20 fold
polychaetes: 40 fold
brittlestars: 133 fold
* substantial decrease in
number of organisms
from pre- to during and
post-drilling at both 100
m and 200 m
ND
* below discharge point:
same abundance of fauna
in cuttings samples as in
"normal" sea bottom at
8.5 months
* specimen abundance
significantly decreased
along 100 m periphery;
•effect to 1,000m
ND
ND
-------
9-4
Exhibit 9-1. Marine Studies of Water-Based Drilling Fluid Impacts (Continued)
Study Source
CSA, 1988
CSA, 1989
CSA and Barry
Vittor & Assoc.,
1989a,b
Bothneretal.,
1985
Steinhaueretal.,
1990
Northern
Technical
Services, 1981
Study Site/
Location
Gainesville Area
Block 707
Florida
Continental Shelf
Pensacola Area
Block 996
Gulf of Mexico
Alabama State
Waters
Georges Bank
Block 3 12
Block 4 10
Atlantic
Continental Shelf
Santa Maria
Basin
California
Continental Shelf
Beaufort Sea
RIST Well
Alaska Coastal
Water
Depth (m)
21
50-60
40-60
90-410
8
Impacts (a)
Sediment
* increase in Ba:Fe ratio:
90% at 4,000 m
* increase in Cr cone:
11% at 300m
* almost 3 fold increase in Ba
and Ba/Fe ratio at 2,000 m
* 2 to 5 fold increase in Ba at
1,000 m
* 25% of barite deposited
within 6 km
* Ba transport detected at 35
km
* cuttings observed within 500
mat Block 3 12
* cuttings observed at 2 km
station at Block 4 10
ND
* cuttings accumulation
observed:
@ discharge pt: 5-6 cm
@ 3 m: 2-3 cm
@ 6 m: 1-2 cm
@ 30 m: <0.5 cm
* elevated Co, Cu within 50 m
Biota
* absence of seagrass
within 300 m
* growth inhibited beyond
300m to 3. 7 km.
* 77% decrease in
seagrass leaf count at 3.7
km
* burial of live bottom
communities at 25 m
* reduced bryozoan
coverage within 2,000 m
of discharge
* elevated As in oysters
behind barrier islands
ND
* sediment flux related to
decreased soft coral
coverage
* statistical power of
study limited to 70% or
greater
* decrease in number of
organisms 3 months after
discharge
ND = no data
(a) Results presented represent a range of time periods relative to active drilling. Some surveys were
conducted while drilling was ongoing; others took place many years after drilling ceased. For greater detail
than presented in this summary, please refer to the individual study summaries that follow.
-------
9-5
impacts but do not document larger-scale impacts. However, these studies are not sufficient to
conclude that regional-scale impacts are not occurring.
Field studies of drilling fluid discharge plumes indicate that, as a generalization, plume
dispersion is sufficient to minimize water quality impacts and water column toxicity concerns in
energetic, open marine waters, such as the domestic OCS.
In shallow water areas (e.g., less than 5-10 meters), field data on plume dispersion are
minimal, and are insufficient to conclude that water column effects present only a minor potential
concern. Some modeling data suggest water quality and toxicity parameters could be adversely
affected under shallow water conditions. Also, in water depths of less than 5 meters, the
reliability of most models that are suitable for application to drilling fluid discharges becomes
questionable. Thus, the potential water column impacts of those discharges in shallow waters
(<5 meter) is not known with any degree of confidence.
The degree of impact of drilling fluids and cuttings on benthic and demersal species is
highly dependent on a number of local environmental variables (e.g., depth, current and wave
regimes, substrate type) and on the nature and volume of the discharges, including cuttings size
and the location of the outfall in the water column. Impacts can be considered to fall into two
relatively distinct categories: short-term effects due to either toxicity or burial by drilling fluid
and/or cuttings; and longer-term effects due to chemical contamination or physical (textural)
alteration of the sediments.
For example, Cook Inlet and Tanner Bank sites are both characterized as having strong
currents. At these depths, currents significantly affect cuttings sedimentation patterns as well as
cuttings transport along the bottom, entrainment and reworking of the sediment. Under these
conditions, the investigators did not observe discrete cuttings piles which tend to form in more
quiescent locations (Ray and Meek, 1980; Houghton et al., 1980). In the Gulf of Mexico,
cuttings piles 150 m in diameter and 1 m in height have been reported (Zingula, 1975). On the
other hand, cuttings seemed to be present at relatively farther distances in more energetic
locations (Houghton et al., 1980; see below).
The extent of cuttings accumulation is important in assessing benthic impacts. A general
trend of impacts is that specimen abundance decreased closer to the well. Several studies cited
that the lowest numbers of organisms were at the 100 m stations, which were the closest stations
to the well in these studies. Even in the dynamic location of Cook Inlet, authors reported that
number of organisms and species diversity were significantly lower at the 100 m and 200 m
sampling points than the control location (Lees and Houghton, 1980). These local effects have
-------
9-6
been ascribed to both physical changes in sediment texture and toxic effects. However, studies
have not been designed to discriminate between these two potential causative factors.
The Cook Inlet Continental Offshore Stratigraphic Test (COST) well study was the only
study reviewed that carefully analyzed sediment cores for the presence of cuttings as well as
conducted chemical analyses. Barium concentrations in the sediment were found to be elevated
in samples containing cuttings (defined by the authors as particles >0.85 mm) as far as 400 m
from the platform (Houghton et al., 1980). These analytical results suggest that some drilling
fluid still adheres to the cuttings and is transported and redistributed together with the cuttings.
This is in contrast to the study in which divers observed drilling fluid being washed from the
cuttings as the cuttings dropped through the water column within several meters of the outfall,
although this latter observation was visual in nature (Ray and Meek, 1980).
The most clearly documented point source effect of these discharges has been alterations
in sediment barium (Ba), a tracer for drilling fluids solids. Observations on sediment alterations
from field studies of both single-well and multiple-well facilities include:
Increases in Ba levels of 2-fold to 100-fold above background at the drill site, with typical
values of 10-fold to 40-fold
• Average measured background levels are reached, statistically, at 1,000-3,000 m; single
transect values have been elevated at up to 8,000 m
• Increases in Ba fall off logarithmically with distance from the drill site; regression
analyses indicate background levels are achieved at 2,000-20,000 m.
Increases in a suite of other trace metals associated with drilling fluids (As, Cd, Cr, Cu,
Hg, Pb, Zn) have also been observed. These increases:
• Are of a lower magnitude than seen for Ba (generally not more than 5- to 10-fold above
background)
Are more spatially limited, when compared to background levels, than seen for Ba
(generally withing 250-500 m of the drill site, although increases at 1,000-2,000 m have
been noted)
Are noted consistently as a group, but are variable for any specific metal among the
various studies.
Observations on the long-term, regional scale fate of drilling fluid solids indicate that the
materials may be very widely dispersed over large areas. Dispersion is related directly to bottom
energies of the receiving water (more shallow waters being more energetic than deeper waters).
-------
9-7
• In shallow water (13-34 m) Boothe and Presley (1989) found that only about 6% of
discharged Ba was accounted for within a 3 km radius of three drill sites in northwestern
Gulf of Mexico; in contrast, for three drill sites in deeper waters (76-102 m) within the
same study, the authors found 47% to 84% of the discharged Ba was found within a 3 km
radius
• At these same six sites, Ba concentrations 3 km from the drill sites ranged from 1.2 to 2.9
times predicted background at the shallow water sites and at the deep water sites ranged
from 2.0 to 4.3 times predicted background (Boothe and Presley, 1989)
Drilling fluid solids can be transported over long distances (35-65 km) to regional areas
of deposition, albeit at low concentrations, based on a study of eight wells (Bothner et al.,
1985).
Biological effects have routinely been detected statistically at distances of 200 m to 500 m. Less
routinely, effects have been observed at greater distances (1-2 km). These effects more typically
are found to fall into one of two categories: those that are statistically significant at the level of
individual stations but cannot be integrated into an easily defined pattern or those that are not
statistically significant at the level of individual stations but do form significant correlations at
larger levels of integration. Specific observations are as follows:
The most affected community appears to be seagrass communities. Data on seagrasses
are limited to a single study, but it documented damage much more severe than in any
other study to date. Approximately 9 weeks after the drilling operation commenced,
seagrasses were completely absent within 300 m of the drill site; at a distance of 3.7 km
from the drill site, leaf biomass and leaf numbers showed only a 25% increase compared
to the increases shown at the reference station (CSA, 1988).
• Fauna also have been affected, including changes in abundance, species richness (number
of species), and diversity. Taxa include annelids, mollusks, echinoderms, and
crustaceans.
• Alterations to benthic community structure are virtually always observed within 300 m of
the drill site. However, changes have been noted in some cases at 500-1,000 m, and a
few reports indicate alterations have occurred at 1-2 km.
• Changes have been ascribed to purely physical alteration in sediment texture and to
platform-associated structural effects (i.e., from the fouling community) more frequently
than to toxic effects. These causes are plausible, but there are not systematic studies of
their relative contribution to observed impacts. Also, alterations due to physical causes
may not be any less adverse than those due to toxic pollutants, and may be more
persistent.
-------
9-8
• Bioaccumulation has been observed for a suite of metals (Ba, Cd, Cu, Hg, Ni, Pb, V), but
the magnitude of this effect is usually low (i.e., less than a factor of 5).
Synthetic-Based Fluids
The extent of the literature on field studies of impacts from discharges of SBFs is much
more limited than for impacts from discharges of WBFs. EPA has identified and reviewed five
studies, totaling six sites, for this environmental assessment. A summary of the results are
provided in Exhibit 9-2. Others survey sites, and additional surveys at some of these same six
sites also exist. However, difficulties occurred in trying to review this additional information:
some studies are only available in Norwegian while others are proprietary or confidential in
nature. The results of the five studies reviewed also present variability in terms of assessing the
potential for adverse impacts from SBFs. This limited and varied information base makes
drawing any generally applicable conclusions a difficult, and potentially unreliable, endeavor.
One study on the domestic continental shelf, in 39 m of water in the Gulf of Mexico,
discharged a relatively small amount (354 bbl) of PAO SBF adhering to the drill cuttings
(Candler et al., 1995). At a maximum, this amount represents approximately 45 metric tons of
discharged olefins, which compares to North Sea discharges of approximately 100 - 180 metric
tons of synthetic base fluid at each of three study sites. The top 2 cm of sediment were sampled
at stations only out to 200 m, with 2,000 m reference stations. Synthetic base fluids, as measured
by total petroleum hydrocarbons (TPH), showed substantial (60% - 98%) decreases between the
first and second sampling surveys (i.e., after 8 months) at all but the closest, 25-meter station.
How much of this decrease was due to biodegradation, as opposed to sediment redistribution and
reworking, is uncertain. Although the data are somewhat difficult to interpret, it appears that
little further reductions in TPH occurred between the second and third surveys (a 16-month
period). This finding for a PAO synthetic base fluid contrasts with North Sea data on ester- and
ether-type synthetic base fluids that indicate a continuing decrease in synthetic fluid over time.
Limited analysis of benthos (the third survey only) indicated significant differences in the
diversity scores at 25 m and 50 m stations compared to reference stations.
For three North Sea study sites, EPA reviewed the impacts from the discharge of SBFs.
At a well site (K14-13) in the Dutch sector located at a depth of 30 m, approximately 180 metric
-------
Exhibit 9-2. Marine Studies of Synthetic-Based Drilling Fluid Impacts
Study Source
Candler et al., 1995
Daanetal., 1996
Smith and May,
1991; Schaanning,
1995
Bakkeetal., 1992 (in
Norwegian, as cited
in Schaanning,
1995)
Aquaplan, 1996 as
cited in Viketal.,
1996
Gj0s et al., 1995 as
cited in Viketal.,
1996
Study Site/
Location
NPI-895
Gulf of Mexico
Continental
Shelf
K14-13
North Sea/
Dutch
Continental
Shelf
Ula 7/12-9
North Sea/
Norwegian
Continental
Shelf
Gyda 2/1-9
North Sea
Eldfisk
Tordis
Type of
Synthetic
Base Fluid
polyalpha-
olefin (PAO)
ester
ester
ether
PAO
PAO
Water
Depth
(m)
39;
shunted
30;
shunted to
5 m above
seabed
67
NA
NA
181-218
Cuttings/Synthetic-
Based Fluids
Discharged
441 bbl cuttings plus
354 bbl adhering
fluids; estimated at
<45 metric tons of
PAO
361 m3 synthetic-
based fluids;
~ 180 metric tons of
ester
749 metric tons
cuttings containing
96.5 metric tons
synthetic ester
160 metric tons
synthetic ether
1,155 metric tons
57 metric tons
Impacts
Cone, of Base Fluid in
Dry Sediment
(mg/kg)
134,428 @ 50 mb
2,850 @ 50 mc
3,620 @ 50 md
1,460 @ 200 mb
297 @ 200 mc
280 @ 200 md
706 @ 75 me
393 @ 75 mf
84 @ 75 mg
300 @ 125 me
834 @ 125 mf
10 @ 125 mg
54 @ 200 me
161@200mf
55 @ 200 mg
85,300; 46,400; 208
@ 50, 100 and 200 me
0.21, 0.22, and 1.34
@ 50, 100 and 200 m
0.38 (max.) @ 200 m
2,600 @ 50 m>
14,700 @ 50 mh
3.7@50md
236 @100-200 m>
96 @100-200 mh
2.1 @100-200md
79.8 @ 2,000 m
8,920 @ 500 m
82 @ 1,000 m
Biota a
Not Available (NA)
NA
Abundance/Richness
depressed @ 50 md
NA
Abundance/Richness
depressed @ 200 mf;
Richness depressed @
500m
Abundance/Richness
depressed @ 200 mh
Abundance/Richness
depressed @ 100 me
No Impact11
No Impact1
Reported as
"Remarkably weak"
(only 4 stations
sampled)
NA
NA
-------
Exhibit 9-2. Marine Studies of Synthetic-Based Drilling Fluid Impacts (Continued)
Study Source
Gj0s, 1995 as cited in
Viketal., 1996
Gj0s et al., 1992 &
1993 as cited in Vik
etal., 1996
Johansen, 1996 as
cited in Viketal.,
1996
Larsenetal., 1995 as
cited in Viketal.,
1996
Feldstedt, 1991 as
cited in Viketal.,
1996
Study Site/
Location
Loke
Sleipner A
Sleipner 0
Gyda 2/1-9
Heidrum
Ula 2/7-29
Ula 7/12-A6
Type of
Synthetic
Base Fluid
ester
ester
ester
ether
acetal
acetal
acetal
Water
Depth
(m)
76-81
76-81
70
342-375
67
67
Cuttings/Synthetic-
Based Fluids
Discharged
180 metric tons
399 metric tons
Petrofree
236 metric tons
Finagreen
380 metric tons
Petrofree
160 metric tons
208 metric tons
130 metric tons
230 metric tons
Impacts
Cone, of Base Fluid in
Dry Sediment
(mg/kg)
93 @ 250 me
5 @ 500 me
10 @ 250 mh
5 @ 500 mh
50 @ 250 me
20 @ 500 nf
25 @ 250 mh
<5 @ 500 mh
400 @ 250 m
30 @ 500 m
2,500 @ 250 m
250 @ 500 m
2,600 @ 50 m>
420 @ 100 m"
150 @ 200 m>
14,700 @ 50 mh
50 @ 100 mh
25 @ 250 mh
618@500mh
33.3 @ 1,000 mh
56,888 @ 50 mk
10,000 @ 100 mk
2,368 @ 200 mk
2,000 @ 50 mh
2,000 @ 100 mh
1,000 @ 200 mh
650 @ 200 mf
156 @ 500 mf
18 @ 1,000 mf
Biota a
NA
NA
NA
NA
NA
NA
NA
NA
-------
Exhibit 9-2. Marine Studies of Synthetic-Based Drilling Fluid Impacts (Continued)
Study Source
CS A (API) 1998,
Gulf of Mexico
Continential Shelf
LGL Ecological
Research Assoc.,
1998
Gulf of Mexico
Continental Slope
Study Site/
Location
Grand Isle 95A
S. Marsh
Island 57C
S. Timbalier
148 E-3
Pompano
Type of
Synthetic
Base Fluid
internal
olefin
linear alpha
olefin and
internal
olefin
internal
olefin
90% LAO
10% ester
Water
Depth
(m)
61
39
33
565
Cuttings/Synthetic-
Based Fluids
Discharged
1,394 bbl cuttings
plus 1,31 5 bbl
adhering fluids
448 bbl cuttings plus
850 bbl adhering
fluids
782 bbl cuttings plus
2,390 bbl adhering
fluids
6,263 bbl adhering
fluids (prior to 1997
survey)
1,486 bbl additional
fluids (prior to 1998
survey)
Impacts
Cone, of Base Fluid in
Dry Sediment
(mg/kg)
23,000 @ 50 md
6,700 @ 50 mB
41 @ 100 mB
1,900 @ 50 m1
165,051 @75mm
198,320 @ 75 nf
Biota a
NA
NA
NA
Polychaete densities
40 times higher than
background; gastropod
densities 3,000 times
higher than
background n
Abundance = No. of organisms; Richness = No. of taxa
9 days post discharge (pd)
8 months pd
2 years pd
1 month pd
4 months pd
11 months pd
1 year pd
2 years pd; Schaanning, 1995
immediately pd
3 months pd
10 months pd
1997 survey
1998 survey
-------
9-12
tons of ester SBF (resulting from the discharge of approximately 477 tons of adherent synthetic
base fluid) were discharged (Daan et al., 1996). Surveys occurred 1 month, 4 months, and 11
months after SBF discharges ceased. The synthetic base fluid was detected in the upper 10 cm of
sediment to a distance of 200 m from the discharge site (which was the farthest distance sampled
in the second survey). During the second survey, sediment ester levels appeared to increase, a
phenomenon that the authors surmised was related to resuspension and transport of highly
contaminated and heterogeneous sediment very near the discharge becoming spread out and more
well-mixed over a larger area between surveys. Significant decreases of 65% to 99% in sediment
ester levels occurred, however, between the second (4 month) and third (11 month) surveys.
Effects on benthos were more extensive: for the second survey effects were noted at 500 m
stations, with much more pronounced effects within 200 m. Benthic analyses from the third
survey indicated significant effects occurred only to 200 m. Additionally, recolonization and
recovery at 500 m to 3000 m stations were also noted as occurring within the study area after 11
months.
EPA reviewed results from a study of the discharge of 97 metric tons of an ester SBF in
the Norwegian sector (Ula well 7/12-9) in a water depth of 67 m (Schaanning, 1995). Surveys
were conducted immediately, one year, and two years after discharge ceased. Sediment ester
levels fell dramatically, with both maximum values and average values within 1,000 m
decreasing more than five orders of magnitude over the course of the study, and more than three
orders of magnitude between the first and second surveys. Benthic organisms were severely
impacted out to 100 m in the first survey (immediately) after discharge ceased. Evidence of
minor macrobenthic community changes (no details provided) were cited two years after the
discharge ceased.
EPA reviewed results from a study of the discharge of 160 metric tons of an ether SBF in
the Norwegian sector at the Gyda well site 2/1-9 that were presented in Schaanning (Bakke et al.,
1992; 1993 as cited in Schaanning, 1995). Schaanning reports results from three surveys, one in
1991, 1992, and 1993. Ether levels seemed to fall continuously, with mean ether levels
decreased by factors of 2-fold and 10-fold for 1992 and 1993 compared to 1991. This degree of
degradation is considerably less than that reported above for the ester SBF at the Ula well site.
Schaanning interpreted these results as indicating that a lag phase occurred in the biodegradation
of the ether base fluid. Benthos were analyzed only at four stations in 1993; no data were
reported, although Schaanning states that Bakke et al. (1992) observed "remarkably weak"
effects.
There is very little information upon which to base any broad conclusions about the
potential extent of impacts from SBFs. It appears that biological impacts may range from as little
as 50 m to as much as 500 m shortly after discharges cease to as much as 200 m a year later.
-------
9-13
Ester SBFs appear to be more readily biodegraded in North Sea studies than an ether SBF; the
Gulf of Mexico study suggests PAOs also are less biodegradable than esters. Also, although
esters appear to be readily biodegraded, one study indicates the persistence of uncharacterized
"minor" impacts on benthos after synthetic base fluid levels have fallen to reference levels.
These limited data, however, are not entirely adequate as a basis for any reliable projections
concerning the potential nature and extent of impacts from discharges of SBFs. However, the
reported adverse benthic community impacts are expected, given the basic SBF and marine
sediment chemistry, the level of nutrient enrichment from these materials, and the ensuing
development of benthic anoxia. The extent and duration of these impacts are much more
speculative. Severe effects seem likely within 200 m of the discharge; impacts as far as 500 m
have been demonstrated. The initiation of benthic recovery seems likely within a year, although
it also seems unlikely that it will be complete within one year. And the relative impacts of the
various types of SBFs is speculative given the limited marine sediment applicability of available
laboratory methods for assessing toxicity and biodegradability and the paucity of field data for
laboratory versus field correlations.
Drilling Fluid Impact Comparison
As described in the preceding sections, the reviewed seabed surveys measured either
sediment or biologic effects from discharges of either WBFs or SBFs. Specifically, indicators of
drilling fluid impact of seabed sediments are determined by measuring drilling fluid tracer
concentrations (as either barium or SBF base fluid) in the sediment at varying distances from the
drill site in an attempt to determine fluid dispersion and range of potential impact. Another class
of impacts frequently measured are benthic community effects. The purpose of these studies is to
assess potential drilling fluid affects such as increased metals and/or anoxia on biota.
Exhibit 9-3 summarizes the major impacts arising from the discharge of WBFs and SBFs.
The distance in which SBF tracers are detected (100 m to 200 m) is much less than that of WBF
(400 m to 35 km). Likewise, the impact on the biologic community is not as far-reaching for
SBFs (50 m to 500 m) as for WBFs (25 m to 2,000 m).
9.2.2 Study Limitations
One of the major limitations in comparing data between the seabed surveys was the
inconsistency in sampling methodology that was used, both spatially and temporally. The
reviewed studies were often conducted using a variety of different sampling methods. Spatially,
sampling locations were determined or chosen in one of several ways. Some studies established
monitoring sites located radially from the discharge point. Others chose the drilled well location
as the hub of the radial or intersecting transects. The Candler seabed study used the four
-------
9-14
Exhibit 9-3. Water-based and Synthetic-Based Drilling Fluid Impact Comparison
Studied
seabed
impact
Elevated
tracer cone.
(d)
Negative
community
impact
Water-Based Fluids (a)
Sediment
Fraction of
studies
noting
impact (c)
9/10
Max
range of
impact
400m-
35km
Biota
Fraction of
studies
noting
impact (c)
1/1
7/8
Max
range of
impact
1.6km
25m-
2000m
Synthetic-Based Fluids (b)
Sediment
Fraction of
studies
noting
impact (c)
4/4
Max
range of
impact
100m-
200m
Biota
Fraction of
studies
noting
impact (c)
~
4/4
Max
range of
impact
—
50m-
500m
(a) A total of 17 water-based fluid seabed survey studies were reviewed.
(b) A total of 4 synthetic-based fluid seabed survey studies were reviewed.
(c) The fraction equals the number of studies noting an effect from the total number of studies measuring the
corresponding impact.
(d) For water-based fluids the measured tracer in both sediment and biota was barium (see Exhibit 9-1); for
synthetic-based fluids either total petroleum hydrocarbons or the synthetic fluid was measured (see Exhibit
9-2).
compass directions as the transects, whereas the Daan study used only two transects, the direction
of which was determined by the prevailing water current (Candler et al., 1995; Daan et al., 1996).
In one study (Daan et al., 1996), results of the pre-discharge survey were the basis for
changing the transect orientations from cross-bathymetric to isobathymetric orientation. This
invalidates comparison between these survey years. In another study (Schaanning, 1995), two
reference stations were reasonably located at 5-6 km distance from the well site. However, these
reference stations also showed a clear temporal pattern in sediment Ba and total hydrocarbon
(THC) levels that suggest potential drilling waste contamination. Specifically, reference station
THC levels decreased from 2.3 mg/kg to 0.25 mg/kg, to 0.09 mg/kg over 1990, 1991, and 1992
surveys. Reference station barium levels decreased from 265 mg/kg to 78 mg/kg to 55 mg/kg
over the same period. These results throw some doubt on the validity of the reference stations
despite their appreciable distance from the drill site.
Other variations in sampling are the sampling point locations on each of the transects.
For example, sampling stations in one study were located 100 m and 500 m from the discharge
point (U.S. DOI, 1977). In another, sampling stations were located much closer, e.g., 25, 65, and
85 m (CSA, 1988). In addition, several seabed surveys of WBF discharge used underwater TV
-------
9-15
(UTV) in which divers filmed the seabed. However, the UTV of locations where cuttings were
noted were not necessarily the location of these sampling stations (CSA, 1988).
Sample collection protocols often varied between studies. For example, in the North Sea
Ula Well site seabed study, only the top 1 cm of sediment was collected and analyzed for ester
concentrations (Smith and May, 1991). Other studies have collected deeper sediment cores, e.g.,
from the upper 2 cm for the Gulf of Mexico study site, or from the upper 10 cm for the Dutch
sector North Sea (K14-13) study sites. This difference in sampling protocol has led authors to
different conclusions. In the Smith and May study, the authors concluded that because the SBF
base fluid was no longer detected in the sediment seabed, recovery had occurred. Other authors
have concluded that synthetic based fluid migrated deeper into the sediment, suggesting that
vertical redistribution is occurring as well as horizontal migration and redistribution.
Temporally, sampling was conducted using many different time interval configurations.
Several studies conducted a pre-discharge survey in order to collect background information on
the site and as a comparison or control for the drilling impact assessment. However, not all
studies conducted pre-discharge surveys. Instead, reference stations, often located at arbitrary
distances from the discharge point or well were used. Often, the seasonality of the pre-discharge
survey was not maintained in later post-discharge surveys. Biologic parameters such as
abundance, species diversity, and species richness are particularly seasonally dependent. Though
spatial reference stations provide relative data to that collected in the vicinity of the discharge
point, a combination of pre-discharge and post-discharge sampling surveys during the same
season provides a more accurate comparison.
Though most studies reviewed included at least one reference station within the study
design, several studies, such as the Mustang Island, Texas study (U.S. DOI, 1977) did not collect
samples from such a station. The importance of a reference station is to provide the background
or control information against which changes can be measured. The absence of background data
during each sampling event discounts environmental effects, such as the above mentioned
seasonal effects impinging on a larger area.
Several studies, such as that in the Beaufort Sea conducted the pre-drilling survey in the
early spring, the first post-drilling survey in late spring and the final survey in late summer
(Northern Technical Services, 1981). Benthic community structure undergoes significant
changes during the spring and summer as growth and development occurs. This is compounded
by the Arctic location which has a very short but intense growing season. The authors in this
study mention seasonal impacts as a source of data variability, however, they neither designed the
study to account for this variability nor conducted an analysis of the developmental effect on the
benthic community during the growing season. Instead, the lack of a decrease in values of
-------
9-16
abundance was interpreted as an indicator of no impacts by drilling effluents, rather than an
indicator of potential interference in benthic growth (Northern Technical Services, 1981). The
absence of a reliable temporal control results in a dependence on spatial reference station
integrity, which may be compromised by discharge impacts or natural interstation differences.
Due to the importance of sampling methodology in influencing the type of results
generated, the lack of a standard sampling protocol or methodology affects the level of
confidence in the data. Therefore, data generated from different methods may not always be
directly comparable.
Limitations were also found in data analysis and interpretation as presented by the
authors. One issue was that of the treatment of data outliers. In the Candler synthetic-based
fluid study, the mean total petroleum hydrocarbons (TPH) was used to represent the
concentration of TPH in the sediments. However, a closer look at the raw data reveals one
replicate sample with a large TPH concentration decrease and three replicates with a
concentration increase. The presentation of average TPH in all replicates masks a potential trend
demonstrating synthetic-based fluid transport.
Two issues related to data analysis concern the broader environmental field study
problems of natural, sampling, and analytical variability as well as the statistical power of
analyzing and interpreting the data gathered. Because of high levels of natural, sampling, and
analytical variability and high costs inherent to marine field studies, the statistical power of such
studies is limited. That is, in order to detect an effect that is statistically significant, the
magnitude of the change in a given parameter ranges from "large" for chemistry data to "very
large" for biological data. Many of the surveys reviewed concluded that the discharge of drilling
fluids and cuttings do not produce an effect on biota or have shown statistically significant
adverse effect only to a limited spatial extent, i.e, to several hundred meters. For example, the
CSA, 1989 study at the Pensacola Block 996 states that "...only catastrophic, large scale changes
(e.g., complete mortality) would be evident from these [observed photographic] data. Qualitative
and quantitative visual data revealed that such mortalities did not occur." Even in the Santa
Maria Basin study, one of the most sophisticated and well-funded studies conducted, sampling at
60 photoquadrants per station per cruise resulted in the ability to statistically resolve 70%
reductions or greater in coral coverage. This level of detectability gives some measure of
definition to and confidence in the study's conclusion that "No statistically significant changes
were noted."
In summary, the lack of standard sampling methodology, differing monitored and
analyzed parameters and differing study purposes presented in the reviewed articles severely
limits the ability to compare effects of WBF and SBF on the seafloor. However, realizing the
-------
9-17
data limitations, useful information can be extracted from the various studies and used in
evaluating general trends and ranges of impacts.
9.3 Summary of Relevant Field Studies
9.3.1 Water-Based Fluids
Zingula, R.P. 1975. Effects of Drilling Operations on the Marine Environment, m: Conference
Proceedings on Environmental Aspects of Chemical Use in Well-Drilling Operations,
Houston, Texas, May 21-23, 1975.
The author described observations of cuttings piles in drilling and post-drilling sites in the
Gulf of Mexico. According to the author, diver surveys and side scan sonar records have shown
typical accumulation in the Gulf of Mexico to be approximately 150 feet in diameter (46 meters),
with the outline being circular, elongate, or star burst, depending on currents. Maximum
elevation of these piles immediately after drilling a well appears to be less than 3 feet (1 meter).
Several months after drilling, the height of the cuttings piles is less than 6 inches. No specific
observations were cited to support these data.
In 1971, cuttings piles were photographed while drilling occurred in South Timbalier
Block 111. The water depth was approximately 80 feet (24 meters). Photographs were taken
below the platform to illustrate "normal" bottom conditions and 70 feet downcurrent where
cuttings were present. According to the author, mobile organisms such as crabs were moving
around on top of the fresh cuttings piles.
In order to observe cuttings after cessation of drilling, a site was chosen in South
Timbalier Block 172, which had not been drilled for 8-1/2 months. Water depth was 110 feet
(33.5 meters). The first dive was to record "typical" bottom conditions in the Gulf, outside the
area of any cuttings accumulation. The sea bottom consisted of a thin surface layer of very soft
and unconsolidated mud, underlain by sticky clay with some sand. The bottom was highly
burrowed, and there were numerous whole and broken mollusk shells.
The second dive identified a pile of cuttings. The surface was also highly burrowed,
indicating the presence of numerous benthic organisms. In addition, there was a thin
accumulation of very soft and unconsolidated mud, indicating that marine sediments are already
covering the cuttings.
A sample was taken of the top two inches of sediment cuttings at the location of the
second dive. The cuttings were somewhat rounded by partial disaggregation of the clays from
-------
9-18
the swelling due to seawater adsorption and possibly from abrasive current action. These clay
chips also showed a brownish oxidation on the exterior, further evidence that the chips were
undergoing weathering.
Fauna in the cuttings sample were compared to that found in the "normal" sea bottom
sample. According to the author, both samples contained essentially the same fauna, and in
essentially the same abundance. Present in both were nearly 30 species of foraminifera, more
than 15 species of mollusks and micromollusks, several species of bryozoans (both free
specimens and coating mollusk shells), echnoid spines, ophiuriod ossicles, crab fragments, etc.
Ray, J.P. andE.A. Shinn. 1975. Environmental Effects of Drilling Muds and Cuttings, in:
Conference Proceedings on Environmental Aspects of Chemical Use in Well-Drilling
Operations, Houston, Texas. May 21-23, 1975.
Diver observations of the benthic environment in the vicinity of a drilling platform were
described by the authors. During cuttings discharge, the heavier cuttings fall straight to the
bottom to add to the cuttings pile. According to the authors, there is no doubt that sessile benthic
organisms which cannot move about are buried by the cutting pile.
In depths below the effects of wave action, the cuttings piles produce a hard substrate
capable of supporting a diverse and large number of organisms. It must be noted that this study
did not collect any sediment cores so that no accounting of the benthic community was taken,
either pre- or post-drilling. The authors, however, concluded that there are no observable
detrimental effects on the marine life beneath Gulf of Mexico platforms.
U.S. Department of the Interior. 1977. Baseline Monitoring Studies, Mississippi, Alabama,
Florida, Outer Continental Shelf, 1975-1976. Volume VI. Rig Monitoring. (Assessment of
the Environmental Impact of Exploratory Oil Drilling). Prepared by the State University
System of Florida, Institute of Oceanography. Contract 08550-CT5-30, Bureau of Land
Management, Washington, D.C.
A study was conducted to provide a pre-, during-, and post-drilling assessment of selected
biological, chemical and geological aspects of the environment in the vicinity of an exploratory
drilling well. The monitoring survey was centered on a drilling location near the north lease line
of Mustang Island (Texas) Block 792. Water depth was approximately 36m.
The sampling pattern was in the form of a wheel with eight spokes centered on the well.
Sampling points were located at distances of 100, 500, and 1,000 m from the drill site along each
spoke. Thus, there were a total of twenty-five sampling points, including the drill site before and
after operations and twenty-four points during drilling.
-------
9-19
For clay mineralogy and standard sediment parameter analyses, two sediment samples
were collected from each station by a diver filling PVC cores with sediment. A 9.1-m semi-
balloon trawl was towed at a speed of three to six km/hour to collect macroepifaunal samples
from each of the sampling points for trace element and histopathological analyses. The low
number of epifauna in the study site limited histopathological examination to specimens of only
two species of nektonic shrimp. One sediment core sample was also collected by divers at each
station. The core was then subsampled for foraminifera and the remainder of the core was
archived.
The clay mineralogy of the bottom sediments consisted predominantly of smectite
followed by illite and kaolinite. Smectite levels did not change throughout the study period,
however, illite levels significantly increased, whereas kaolinite decreased during and after
drilling. Sand, clay and CaCO3 levels increased and silt levels decreased during drilling
operations.
During the active drilling phase, the authors noted that drill cuttings were specifically
observed at only four 100-m periphery stations and one 500-m periphery station. Drill cuttings
were still observed at these same five stations in the after-drilling phase but were notably less
abundant.
The foraminiferal community composition indicated a "stressed environment" prior to
drilling operations, and drilling activities further increased the stress. Total and live specimen
abundance in samples collected during drilling were significantly less than those in the pre-
drilling samples. The greatest effect on specimen abundances occurred along the 100-m
periphery, but adverse effects were demonstrated out to the 1000-m periphery. However, the
authors did not state if the cores at 100 m where the benthic fauna were sampled included
cuttings samples.
Ray, J.P. and R.P. Meek. 1980. Water Column Characterization of Drilling Fluids Dispersion
from an Offshore Exploratory Well on Tanner Bank, in: Symposium, Research on
Environmental Fate and Effects of Drilling Fluids and Cuttings, Lake Buena Vista,
Florida, January 21-24,1980. API, Washington, DC.
From January to March of 1977, a drilling muds and cuttings discharge monitoring
program was conducted from a semi-submersible drilling platform on Tanner Bank, 161 km west
of Los Angeles, California. The drill site was located in 63 m of water. Discharges during the
study were from a 0.3 m diameter pipe located at a depth of approximately 12 m below the
surface of the water. Photographic records were made by scuba divers using 35 mm stills and 16
mm movies. Surveys of bottom conditions directly beneath the discharge and in adjacent areas
-------
9-20
were made from a research submersible. Observations and aerial photographs of plume
characteristics also were made from helicopters.
Diver observations showed that as cuttings exit the discharge pipe, the materials
simultaneously separate in three directions: upward, downward and horizontally. The heavier
cuttings and some associated mud began an immediate vertical drop. Cuttings were often
"glued" together by drilling mud and fell to the bottom as large aggregates. The authors
hypothesized that this may be a mechanism for the transport of small quantities of undiluted
drilling mud directly to the sea floor beneath the discharge point. However, the divers observed
that much of the mud adhering to the cuttings was washed off as they fell through the water
column. These lighter fractions dispersed horizontally under current influences.
Observations made beneath the platform and on the nearby reef from the research
submersible showed no visible signs of mud or cuttings accumulation. The authors stated that
due to the high energy water movements present on Tanner Bank, these results were not
unexpected.
Meek, R.P. andJ.P. Ray. 1980. Induced Sedimentation, Accumulation and Transport Resulting
from Exploratory Drilling Discharges of Drilling Fluids and Cuttings on the Southern
California Outer Continental Shelf. in_: Symposium, Research on Environmental Fate
and Effects of Drilling Fluids and Cuttings, Lake Buena Vista, Florida, January 21-
24,1980. API, Washington, DC.
From January to March of 1977, a drilling fluids and cuttings discharge monitoring
program was conducted from a semi-submersible drilling platform on Tanner Bank, 161 km west
of Los Angeles, California. The drilling site was located in 63 m of water. The authors
investigated sedimentation because of concerns that accumulations of sediments including
cuttings could smother important biotic assemblages such as the relatively rare stylasterine
hydrocoral, Allopora californica.
To evaluate the spatial and temporal distribution of settled solids, 19 sediment traps were
placed at various distances around the exploratory drilling platform. In addition, 9 pre-
operational, 45 operational, and 11 post-operational sediment grabs were taken at varying
distances from the drilling platform to evaluate accumulation and transport of the settling
materials. A pair of modified Van Veen samplers were used to capture undisrupted surface
sediments. Both sediment and grab samples were analyzed for total solids and WBF trace
element concentrations of barium, chromium, and lead using atomic absorption spectroscopy.
Over the 85-day study period, 2,854 barrels of muds and cuttings were discharged.
Cuttings discharge accounted for approximately 96% or 825,530 kg of the total discharged
-------
9-21
solids. Based on particulate composition, water depths and currents, the largest cuttings falling at
speeds of 10 cm/sec fell straight down and would not reach traps just outside the platform
perimeter. An analysis of the materials collected from traps located at 65 m and 120 m
downcurrent of the discharge source demonstrated that finer materials were captured at the 120 m
trap as would be expected given lower settling velocities as particle size decreases. However,
both traps captured some fine cuttings and mud components with low settling velocities (less
than or equal to 1 cm/sec). This indicated to these authors that within 200 m of the discharge,
some aggregation of fine particles has also occurred.
Based on cuttings fall velocities, the decreasing measured sedimentation rate with
increasing distance from the source, and the conglomerate effect of flocculation of drilling fluid
components, the authors stated that the vast majority of the solids unaccounted for most probably
fell to the bottom within the 50 m radius directly beneath the platform. From direct observations
made by divers and submersible craft during the course of this study, who noted the absence of
cuttings piles, the authors concluded that the majority of these settled solids were resuspended
from the sea bed and redistributed. The authors calculated from sediment trap and adjacent pre-
an post-drilling grab data that 70 to 80% of the settled solids and components were transported.
Houghton, J.P., et al. 1980. Drilling Fluid Dispersion Studies at the Lower Cook Inlet, Alaska,
C.O.S.T. Well, in: Symposium, Research on Environmental Fate and Effects of Drilling
Fluids and Cuttings, Lake Buena Vista, Florida, January 21-24, 1980. API, Washington,
DC.
This study presents results of oceanographic studies and measurements and modeling
predictions of the fate of discharged fluids and cuttings in the environment. The Lower Cook
Inlet Continental Stratigraphic Test (COST) well was drilled between June 7, 1977 and
September 26, 1977 with the Ocean Ranger semi-submersible drilling vessel. The well was
located in the central portion of Lower Cook Inlet approximately 57 km WSW of Homer, Alaska
and 38 km ENE of Augustine Island. The water depth at the site was 62 m.
The physical marine environment in Cook Inlet is dominated by large tidal fluctuations
and strong currents. The authors measured these oceanographic parameters. Mean and diurnal
ranges were calculated to be 4.6 m and 5.3 m, respectively. Currents were measured at the
COST well using current drogues and two arrays of Endeco 105 current meters. Current meter
data indicated mean maximum flood currents of 52, 62, and 78 cm/sec for meters placed near the
bottom, at midwater, and near the surface, respectively. Mean maximum ebb currents were 42,
68, and 104 cm/sec, respectively at similar depths.
-------
9-22
The seabed in the COST well area was reported to be typically sand or gravel waves, with
heights occasionally greater than 3 m. Sea floor reconnaissance at the well site and adjacent
areas was conducted using UTV and various bottom samplers. The authors mapped the drilling
mud plume upon discharge using a dye injected into the drilling effluent. In addition, plume
modeling was conducted and results were compared to field data.
Bottom sampling and specially designed drilling effluent traps were used to define
deposition of cuttings on the sea floor in the vicinity of the drilling vessel. Two specially
designed drilling effluent traps were constructed to measure the potential deposition rates and
their particle size distribution. One trap (T-2) was deployed approximately 2.9 km WNW of the
Ocean Ranger; the other trap (T-l) was deployed 100 m NNE of the discharge point from the
platform. Samples from the drilling effluent traps were passed through a 0.85-mm screen and the
portion of the sample larger than 0.85 mm was examined under a microscope on a grain by grain
basis for the presence of cuttings. Approximately 2.4 gm of cuttings were identified in T-l
giving a calculated deposition rate of 5.24 x 103g/hr/m2. No cuttings were identified in the
control trap T-2.
Bottom samples were obtained with a Souter-Van Veen grab sampler at various locations
near the drilling vessel. Core samples 8 cm in diameter were taken from the sampler, sectioned
vertically at 0.5-cm intervals, then screened, and examined for cuttings (defined as particles
greater than 0.85 mm in diameter). These analyses indicated that the sea floor was sufficiently
mobile to entrain cuttings to a depth of at least 12 cm into the sea floor by the end of the well
(approximately 3 months duration). The maximum cuttings percentage in the sediments
identified in any bottom sample was less than 3 percent by weight and was found 100 m north of
the discharge. Analysis for barium sulfate and barium showed that drilling mud was being
carried to the sea floor with the cuttings. Though the authors do not state in the text, presented
data indicate that 1.34 mm cuttings are found 400 m north of the platform with slightly elevated
barium concentrations of 680 |ig/g in the corresponding sediment sample. Background or pre-
drilling barium sediment concentrations were 560 |ig/g.
The authors concluded that the heavier cuttings material deposited on the sea floor was
entrained vertically into the sediment since the sandy bottom was quite mobile. Benthic
sampling, core analysis, and UTV examination verified that cuttings did not accumulate on the
sea floor as a cuttings pile. In addition, the relatively low increase in sediment barium levels
suggests that near-bottom currents agitate newly fallen cuttings with the natural sands exerting a
washing action that cleanses cuttings of adhering barite.
-------
9-23
Lees, D.C. andJ.P. Houghton. 1980. Effects of Drilling Fluids on Benthic Communities at the
Lower Cook Inlet C.O.S.T. Well, in: Symposium, Research on Environmental Fate and
Effects of Drilling Fluids and Cuttings, Lake Buena Vista, Florida, January 21-24, 1980.
API, Washington, DC.
The major purposes of this study were to (1) determine species composition and
abundance of the benthos in the area of the well site, and (2) evaluate the extent to which changes
were attributable to drilling activities. The Lower Cook Inlet Continental Stratigraphic Test
(COST) well was drilled between June 7, 1977 and September 26, 1977 with the Ocean Ranger
semi-submersible drilling vessel. The well was located in the central portion of Lower cook Inlet
approximately 57 km WSW of Homer, Alaska and 38 km ENE of Augustine Island. The water
depth at the site was 62 m.
Benthic samples were obtained by Ponar grab samples before, during and at the
conclusion of drilling operations. For each of the time periods, the number of species, species
diversity, and number of organisms were evaluated for 10 stations, each at 100 m north, 200 m
north, and the control located 1,700 m east of the drilling vessel.
Results are presented in Exhibit 9-4. The authors mentioned that the increase in the
number of organisms and variation in the number of species and species diversity for the June,
July and September time points (corresponding to before, during and after drilling) is most
probably due to seasonal variations. However, the authors did not discuss that compared to the
control location samples, the number of organisms had substantially decreased in the during- and
post-drilling surveys at both the 100-m and 200-m locations.
Mariani, G., Sick, L., and Johnson, C. 1980. An Environmental Monitoring Study to Assess the
Impact of Drilling Discharges in the Mid-Atlantic. III. Chemical and Physical Alterations
in the Benthic Environment, m: Symposium on Research on Environmental Fate and
Effects of Drilling Fluids and Cuttings. Lake Buena Vista, Florida, January 21-24, 1980.
API, Washington, DC.
The objective of this study was to characterize and determine chemical (trace metal) and
physical (grain size, clay mineralogy) changes of the sediment. This study also analyzed tissue
of three representative benthic taxa for trace metal content: brittle stars (primarily Amphioplus
macilentus), molluscs (primarily Lucinomafilosd) and polychaetes.
Two benthic sampling surveys were conducted. A pre-drilling survey was conducted in
July and August 1978 and a post-drilling survey was conducted in July 1979. The pre-drilling
survey area comprised a 1.6 km radius around the well site while the post-drilling survey was
extended to a 3.2 km radius.
-------
9-24
Exhibit 9-4. Comparison of Sampling Area of Averages for Numbers of Species,
Organisms, and Species Diversity for the Survey Periods
Survey
Period
June
July
September
June
July
September
June
July
September
100-m
200-m
Control
Mean number of species (S)
9.9 ±3. 2 (a)
9.0±2.1
10.7 ± 1.6
12.4 ±2.5
11.3±2.7
8.5 ± 3.1 (b)
17.5 ±3.5
15.8 ±5.7
Mean number of organisms (N)
35.1±21.3a
28.2 ± 14.4
59.7 ±29.9
41.8±9.9
41.4 ±20.5
43.3±37.4b
80.0 ±61.4
183.7 ± 110.4
Mean species diversity (H)
2.10±0.4a
1.98 ±0.51
2.00 ±0.23
2.16 ±0.48
2.17 ±0.23
1.51±0.31b
2.70 ±0.40
1.78 ±0.54
(a) Based on samples 3, 4, 11, 16, 17, 18, 19 in the area of both 100-m and 200-m stations.
(b) Based on samples 28, 29, 30, and 31 about 1,000 m from Anchor Buoy 4 (AB-4).
Six samples were collected with a Smith-Mclntyre or modified Ponar Grab at each station
for the physical, chemical, and biological analyses. Upon retrieval of each grab, two sediment
cores (one for sediment granulometry and one for trace metal analyses) were taken near the
center of the grab.
The physical alterations that took place during the post-drilling survey included increased
percentages of clay size particles within the immediate vicinity of the well site (46 meters) and
extending out to approximately 800 meters. The increased percentages of clay within the
sampling grid were accompanied by changes in proportions of clay minerals in the area. The
authors stated that these changes in clay percentage and mineralogy suggest that fine materials
were deposited around the well site during drilling operations.
Increases in the concentration of lead, barium, nickel, vanadium, and zinc for bottom
sediments were detected during the post-drilling survey. The authors presented metals
concentration data as a spatial distribution, highlighting the trend of metals in sediment
concentrated around the drill site in the pre-drilling survey and distributed at low but fairly even
concentrations to 1.6 km in the post-drilling survey. Barium concentration increased 21 fold at
1.6 km, lead increased 3.6 fold at 200 m, nickel increased 2.5 fold at 100 m, and vanadium
increased 4 fold at 100 m.
-------
9-25
Analysis of tissue samples of brittle stars, molluscs and polychaetes collected during the
post-drilling survey revealed that each group had significantly higher barium and mercury
content than tissue samples collected during the pre-drilling survey. The barium concentration in
mollusks, brittlestars, and polychaetes collected at 1.6 km increased 20 fold, 133 fold, and 40
fold, respectively, whereas mercury concentration increased 4 fold, 18 fold, and 30 fold,
respectively at the same distance. Increased mercury content was detected in these organisms
despite the fact that data showed mercury concentrations in the sediment were below the
detection limit of 0.05 //g/g, indicating that the mercury was bioaccumulating.
Menzie, C., Maurer, D., and Leathern, W. 1980. An Environmental Monitoring Study to Assess
the Impact of Drilling Discharges in the Mid-Atlantic. IV. The Effects of Drilling
Discharges on the Benthic Community, in: Symposium on Research on Environmental
Fate and Effects of Drilling Fluids and Cuttings. Lake Buena Vista, Florida, January 21-
24, 1980. API, Washington, DC.
The objective of this paper was to describe the short-term environmental effects of
drilling fluids and drilled cuttings on marine benthos around exploratory well NJ 18-3, Block 684
on the Mid-Atlantic Continental Shelf. The study was conducted within two weeks following the
termination of drilling. The leased block was located approximately 156 km off the coast of New
Jersey and had an approximate water depth of 120 meters.
Two surveys were conducted to examine the abundance and composition of the benthic
fauna in the vicinity of the well site. A pre-drilling survey was conducted in July and August
1978 and a post-drilling survey was conducted in July 1979. The pre-drilling survey area
comprised a 3.2 km diameter area around the well site while the post-drilling survey was
extended to a 6.4 km diameter area.
UTV surveys were conducted during the pre- and post-drilling surveys to provide
information on the spatial distribution of megabenthic epifauna around the well site and to
examine physical changes in the benthic environment resulting from drilling operations. Ten
UTV transects (200-1,000 m in length) were made throughout the survey area during the pre-
drilling survey, while 11 transects (150-900 m in length) were made during the post-drilling
survey.
During the pre-drilling survey, 40 benthic stations were sampled, of which 22 were
analyzed in a radial pattern around the well site, while during the post-drilling survey, 48 benthic
stations were sampled, of which 41 were analyzed. The rest of the samples were held for later
possible analysis. Six grab samples were collected at each station, of which two were analyzed
for fauna while the remainder were held for future analysis.
-------
9-26
Benthic samples were washed on a 0.5 mm mesh sieve to remove silt, clay, and fine
sands. The material retained on the sieve was preserved with 10% buffered formalin-Rose
Bengal solution. Macrobenthos were sorted from these samples and identified with the aid of
stereoscopic and compound microscopes.
Seafloor UTV observations during the pre-drilling survey revealed a nearly featureless
bottom topography interrupted by burrowing and feeding mounds of benthic invertebrates.
During the pre-drilling survey, the sediments were comprised of medium-fine sands with a silt
and clay content of 16-25%. During the post-drilling survey, bottom UTV observations revealed
that sediments in the immediate vicinity (approximately a 75 m radius) around the well site were
comprised of patches of drilling discharges (primarily semi-consolidated, natural subsurface clay
materials) which altered the microtopography of the area. Mounds of this material were
generally less than 10 cm in height. Debris (e.g., small pieces of pipe, tires, rope) was also
observed in the immediate vicinity of the well site. Side scan sonar showed the bottom scour
marks of anchor chains radiating out from the well site. Sediments in areas beyond the
immediate vicinity of the well site appeared similar to those observed during the pre-drilling
survey.
Fish (primarily hake, Urophycis spp.) and crabs (primarily Cancer borealis) increased
substantially between pre- and post-drilling surveys in the immediate vicinity of the well. The
authors speculated that these organisms may have been attracted to the region as a result of the
increased microrelief afforded by the cuttings accumulations. High densities of sand stars were
observed near the well site, apparently associated with accumulations of mussels (Mytilus edulid)
that had fallen from the drilling rig and associated anchor chains.
Sessile megabenthos (pennatulids) and macrobenthos were subjected to burial by drilled
cuttings within the immediate vicinity (i.e., within approximately a 75 m radius) of the well site.
Measures of species diversity, species richness, and species evenness obtained prior to the
onset of drilling were high and relatively constant over the sampling area. Species diversity of
macrobenthos collected during the post-drilling survey were within the general range observed
for the shelf-break region, though some values were lower. The lowest values during the post-
drilling survey were observed in the immediate vicinity of the well site (75 m). Lower numbers
of species generally reflect the lower numbers of organisms observed at some stations.
Based on the patchiness in the distribution of the species and in density, the author
hypothesized that the variability represented differences between plots in which the infauna had
been buried by cuttings and those which had escaped burial or in which recolonization had
occurred, but supporting data were not presented.
-------
9-27
Differences in the nature of infaunal assemblages were particularly clear when pre- and
post-drilling survey data for densities of major taxa were compared. Pooled densities of
annelids, molluscs, echinoderms, and crustaceans were all lower in the post-drilling survey.
In summary, this study concluded that the discharge of drill cuttings caused local and at
least short-term effects on the fauna in the vicinity of the well site. Increases and/or decreases in
abundance were probably related mostly to: (1) physical alterations of the substrate (e.g., rapid
deposition and burial, increased surface reliefer increased clay content of the sediment), as well
as (2) effects of predation by hake, crabs, and starfish. No toxic effects were identified.
EG&G Environmental Consultants. 1982. A Study of Environmental Effects of Exploratory
Drilling on the Mid-Atlantic Outer Continental Shelf-Final Report of the Block 684
Monitoring Program. 1982. Prepared for Offshore Operators Committee. October 1982.
This survey is the second in a series conducted at the exploratory well site NJ 18-3, Block
684 on the Mid-Atlantic Outer Continental Shelf. This survey was taken one year after drilling
operations had stopped at the site. Forty-one sites were sampled ranging from 23 m to 3.2 km
from the discharge location. The study evaluated the fate of drilling fluids discharges based on:
1) percent clay, 2) trace metal concentration (Ba, Cr, V) in the sediment, and 3) benthos impacts
(trace metal concentration in organisms and density of mega and marcobenthos). Analysis of this
survey indicated the percent clay levels decreased from the drill site out to 800 m measured
during the first study, to levels common with predrill levels. However, several patches of
increased clays were measured out to 750 m. Because trace metal leachate levels measured in the
first post-drill survey did not link to discharge characteristics provided by Ayers et al (1980),
analysis for trace metals was limited to barium, chromium, and vanadium (Ba, Cr, V). Ba
measurements from the second study indicate a shift in the Ba concentrations in the direction of
the predominate current (southwest), with 3-fold increases above predrill levels measured to 400
m from the discharge point. There appeared to be an even distribution of megabenthos with
respect to distance from the discharge point. All four dominant macrobenthos, although
depressed below predrill densities, increased from densities found during the first post-drill
survey. Species richness as with abundance increased from the first post-drill survey, however
they did not reach predrill levels. Impacts were seen out to 1.2 km. These impacts were not,
however, correlated to Ba concentration. Chromium in increased concentration from predrill
levels was detected in polychaetes out to 1.2 km from the discharge point.
-------
9-28
Northern Technical Services. 1981. Beaufort Sea Drilling Effluent Disposal Study. Prepared for
the Reindeer Island Stratigraphic Test Well Participants. Under the direction ofSohio
Alaska Petroleum Company. 329pp.
Sohio Alaska Petroleum Company (SOHIO) completed the Reindeer Island Stratigraphic
Test (RIST) well in Prudhoe Bay area of the Beaufort Sea in early 1979. A study was conducted
to evaluate the effects of above- and below-ice discharges. At the time of the study, normal
procedure for handling drilling mud and cuttings from offshore wells was to haul them to an
onshore disposal site.
Test Plot 1 was the discharge location at a water depth of 8 m. Monitoring locations were
oriented radially from the discharge point ranging from less than 5 m to 500 m distance from the
discharge point. The control location was denoted as Test Plot 3 which was about 1 km south of
Test Plot 1.
Results at Test Plot 1 indicated a strong sorting of materials by grain size. Larger
particles were deposited closer to the discharge point while finer materials, including drilling
muds, were deposited further away from the discharge point. Freshwater drilling muds readily
flocculated upon discharge into seawater. According to the authors' observations, these floes
were loosely deposited on the seafloor during winter and could be resuspended with the slightest
agitation.
The authors stated that it is likely that flocculation extends to cuttings since clay-sized
particles in the drilling mud tend to coat cuttings during the drilling process and thus provide
sites for attachment of other clay-sized particles.
Diver observations were conducted at Test Plot 1 on May 4, 1979, 4 days after the test
discharge. A 5- to 6-cm thick accumulation of mud and cuttings was observed on the seafloor in
the vicinity of the discharge point. UTV observations the following day indicated a 2- to 3-cm
deposition at a distance 3 m east of the discharge point. The consistency of the deposited
materials was such that materials would be suspended with the slightest agitation. At a distance
of 6 m east of the discharge site, 1 to 2 cm of loosely deposited drilling effluents was observed.
By a distance of 30 m east of the discharge, accumulation of drilling muds on the seafloor was
estimated to be less than 0.5 cm thick. Organisms observed during the post-discharge survey at
Test Plot 1 included amphipods, a snail, several fish and mysids, an hydroid, an anemone,
numerous snail and isopod tracks, and numerous worm tubes.
Benthic sampling was conducted at Test Plots 1 and 3 prior to and subsequent to the test
discharge of drilling effluents. All samples were obtained using a Petite Ponar bottom grab
-------
9-29
sampler. Fifteen random replicate samples were taken at each of the test plots during sampling
periods on April 7-10, May 9, and August 3-4, 1979. For the April and May surveys, samples
were obtained through holes augered in the sea ice in random 5 m by 5 m squares within each of
the 50 m by 50 m test plots. For the August survey, randomness in samples was achieved by
drifting in a boat within a 25 m radius of the center of the test plot.
Benthic data were analyzed and are summarized in Exhibit 9-5. The authors calculated
the number of taxa, species diversity, evenness and species richness values by pooling the 15
replicate samples taken at each test plot during the sampling period.
Exhibit 9-5. Summary of Benthic Data Collected at Test Plots
Collection Date
April?, 1979
Aprils, 1979
May 9, 1979
May 9, 1979
Augusts, 1979
Augusts, 1979
Test
Plot3
1
3
1
3
1
3
Abundance
(no./m2)
551.1
809.4
1240.0
1529.9
1202.7
2678.0
No. of
Taxa
45
54
63
65
67
76
Shannon
Function of
Diversity
2.96
3.32
3.11
3.50
2.94
3.09
Even-
ness
0.83
0.83
0.75
0.84
0.70
0.71
Species
Richness
6.97
7.91
8.70
8.73
9.30
9.50
Biomass
(gm/m2 wet wt)
10.0
29.4
33.9
59.2
18.4
55.0
1 Test Plot 1 refers to the discharge location and Test Plot 3 to the control location.
The authors did not seem to stress that the time difference in sampling is strongly affected
by the natural growing season. As presented in Exhibit 9-6, from pre-drilling in April to
immediately after discharge in May, there is a significant increase in the number of organisms per
square meter (abundance) most probably due to the beginning of the growing season. From May
to August, there is a 75% increase in abundance in the control location (Test Plot 3) and a 3%
decrease in Test Plot 1. Though the authors do not present the percentage change nor the
percentage difference between the control and test plot data, it is clear that in the time between
May and August there should be a normal increase in numbers of organisms. This lack of
increase in Test Plot 1 implies that the drilling discharges may have interfered with organism
population growth during that time period.
-------
9-30
Exhibit 9-6. Comparison of Abundance Data Collected at Test Plots
Abundance
Increase from April to
May Sample
Increase from May to
August Sample
April 7, 1979
1
551.1
—
—
3
809.4
—
—
May 9, 1979
1
1240.0
125%
—
3
1529.9
89%
—
August 3, 1979
1
1202.7
—
-3%
3
2678.0
—
75%
Trace metal analysis was conducted on replicate Ponar and whole drilling mud samples in
order to detect possible effects of below ice drilling effluent disposal. The majority of the bottom
samples were obtained at random locations within 50 by 50 m of test plot 1 (the discharge site)
and test plot 3 (control site). As indicated by analysis of the samples at each of the sites,
variations of trace metals at the test discharge site was similar to variations found at the control
location. According to the authors, these results of the trace metal analysis confirm that drilling
muds are quite swiftly resuspended and removed from the seafloor after initial settlement.
Bothner, M.H. etal. 1985. The Georges Bank Monitoring Program 1985: Analysis of Trace
Metals. U.S. Geological Survey Circular 988.
This study was designed to establish the concentration of trace metals in sediments prior
to drilling on Georges Bank and to monitor the changes in concentrations that could be attributed
to petroleum-exploration activities. The first cruise of the monitoring program occurred just
before exploratory drilling commenced in July 1981, and nine subsequent cruises were conducted
on a seasonal basis (November, February, May, and July) over a 3-year period. Eight exploratory
wells had been drilled at that time on Georges Bank. The first was started on July 22, 1981, and
the last well was completed on September 27, 1982.
Of 12 trace elements analyzed, only barium was found to increase in concentration during
the period when the eight exploratory wells were drilled. The maximum post-drilling
concentration of barium reached 172 ppm in bulk sediments near the drill site in Block 410. This
concentration was higher than the pre-drilling concentration at that location by a 5.9-fold factor.
No drilling-related changes in the concentrations of the 11 other metals were observed in bulk
sediments at any of the locations sampled in the program. Analyses of sediment trap material for
Ba-enriched matter showed that resuspension can occur up to at least 25 m above the seafloor.
The authors estimated that about 25 percent of the barite discharged at block 312 was
present in the sediments within 6 km of the rig, 4 weeks after drilling was completed at that
-------
9-31
location. In their evaluation of the rate at which barite decreases within the site-specific survey,
the authors considered only the area between the 0.5- and 2-km circles. They also excluded the
actual drill site, where large within-station variability was measured. For almost a year following
completion of the well, the inventory of barite decreased rapidly, with a half-life of 0.34 year.
During the next year, the inventory decreased at a slower rate (half-life of 3.4 years).
To see how far Ba from drilling mud could be traced, the authors analyzed the fine
fraction of sediment at two stations approximately 65 km west of the Block 312 drill site and at
two stations approximately 35 km to the east of the easternmost drill site. At the two western
stations they measured maxima in Ba concentrations during cruises 8 and 10 in 1983. The
authors were surprised to find that maxima in the Ba concentrations, although of lower
magnitude, were also recorded at similar times at the two eastern stations. The maximum value
at one eastern stations on cruise 7 was statistically higher than the mean of the first 6 cruises at
the 99.5 percent level of confidence (t test). These findings were considered significant because
they suggested that Ba in the finest fraction of drilling mud may have been transported over very
wide areas of the bank, to the east as well as to the west.
The barite discharged during the exploratory phase of drilling is associated with the fine
fraction of sediment and was found widely distributed around the bank. Evidence indicated
barium transport in the predominant, westerly current direction as far as Great South Channel
(115 km west of the drilling), and to stations 35 km east of the easternmost drilling site, against
the predominant current. Small increases in barium concentrations were measured also at the
heads of both Lydonia and Oceanographer Canyons, located 8 km and 39 km, respectively,
seaward of the nearest exploratory well.
Throughout the 3 years of monitoring , the concentrations of Ba in bulk sediments from
the upstream control stations were fairly consistent with time. On the basis of those data, the
authors judged that no increase in Ba had occurred at those stations. They found no increases in
the concentration of other metals as a result of drilling at the upstream locations during the 3
years of monitoring. In contrast, there were measurable changes in the concentrations of Ba in
Block 410 (stations 16, 17, and 18).
The scatter in their data indicated to the authors that Ba was not distributed
homogeneously over the sampling area. This heterogeneity was probably caused by the
intermittent discharge of drilling fluids into ocean currents that continuously change direction of
flow throughout the tidal cycle. A few cuttings were found during both year 2 and year 3 at a
station located 2 km to the east of the drill site, in Block 410. On cruise 9, cuttings were
observed at all stations within 500 m of the drill site in Block 312.
-------
9-32
At coring stations 50 km west of transect IE, the authors observed an enrichment of the
Ba/Al ratio in surface sediments and interpreted that as evidence for a small recent addition of
Ba. A rough calculation referred to from an earlier report (Bothner et al, 1984) suggested that
69 percent of the barite discharged by all eight exploratory wells could be accounted for in the
sediments within the western half of a circle 130 km in diameter and centered on station 5. They
then concluded that the barite from drilling mud was associated with the fine-sediment fraction in
low concentration and was widely distributed.
This study demonstrates that drilling fluid solids may be widely distributed over large
areas in relatively short period of time if they are discharged in high energy marine environments
such as the Georges Bank. Transport was observed over distances of 35 - 115 km, both in the
anticipated direction of deposition and opposite that of predominant current flow. This study
indicated that in such environments, assessing low-level, regional-scale contamination effects is
the primary source of concern.
Neff, J. M. M. Bothner, N. Maciolek, andJ. Grassle. 1989. Impacts of Exploratory Drilling For
Oil and Gas on the Benthic Environment of Georges Bank. Marine Environmental
Research 27 (1989).
This study was conducted over a three year period to determine the impact of discharges
from exploratory drilling to benthic community of Georges Bank and was conducted in
conjunction with the previous reviewed article by Bothner et al. (1985). The authors conducted
benthic fauna analyses at 46 sample sites that included 31 sites adjacent to two drilling platforms.
Sampling took place quarterly and pre-, during, and post-drilling. The authors indicated changes
in the benthic communities near the platforms during and immediately after drilling activities,
but attributed these changes to natural changes within the community populations.
Continental Shelf Associates. 1988. Monitoring ofDrillsite A in the Gainesville Area Block 707.
Preparedfor Sohio Petroleum Company, Houston, TX, April 26, 1988. 124pp.
The purpose of this study was to assess the environmental impacts of proposed
exploratory drilling in Gainesville Area Block 707 on several seagrass and live-bottom
communities. Gainesville Area Block 707 is located approximately 60 km from the west coast of
Florida in water depths of 21 m.
Two surveys were conducted and results analyzed. Survey 1 was a pre-drilling survey.
The drill rig moved onsite on May 25, 1984, and began drilling discharges on June 3, 1984.
Survey 2 (August 9 - August 23, 1984) occurred during drilling. A third survey was also
conducted, but because it followed a severe hurricane that disrupted the benthos across a wide
area of the northwest Florida continental shelf, most of the results were not used.
-------
9-33
According to other studies the authors referenced in this area, plant densities or bottom
coverages within offshore seagrass and algae stands range from 20 to 50%. Halophila species
comprise about 79% of the plant material present while various species of microalgae account for
the remainder. Halophila decipiens was found to be the only seagrass species present in the
vicinity of the Block 707 drill site.
Sampling stations were located within 300 m of the discharge point in a radial pattern.
The closest stations were located 25 m, 65 m, and 85 m from the discharge. Live bottom
monitoring stations were located 25 m and 500 m from the drill site and 3 reference stations were
located greater than 9 km from the drilling operations. Six randomly placed quadrants were
permanently established and photographed. An additional 10 stations were established beyond
300 m during survey 2.
During the second survey, visual observations revealed the absence of all seagrass within
300 m of the discharge site. An accumulation of cuttings around the discharge site was also
observed, particularly along the northwest radial within 30 m of the discharge point. Farther
from the drill site, growth was inhibited as a function of the concentrations of the two drilling
effluent indicators, barium and barium iron ratios in the fine-grained fraction (<63 jim) of
surficial sediments.
To determine whether or not exposure to drilling effluents affected the seagrass, the
authors evaluated the relationships between changes of the indicators of discharged drilling
effluents and the changes in standing crop of the seagrass. The indicators of discharged drilling
effluents were the barium concentrations and barium:iron ratios in the fine-grained fraction (<63
jim) of the surficial sediments. The fine-grained fraction was analyzed because barium sulfate in
the discharged drilling effluents is in the silt/clay particle-size range and the sediments around the
drill site were sand. Thus, metal concentrations in the fine-grained fraction were more efficient
tracers of the settleable fraction of the discharged drilling effluents. Logarithmic transformations
of the mean changes of these indicators were used in the correlation analysis.
The authors presented Ba:Fe ratio data as well as chromium concentration data. The data
showed a 90% increase in the Ba:Fe ratio at 4,000 m from the discharge point and an 11%
increase in the chromium concentration at 300 m.
Results of analysis indicated that there were statistically significant negative correlations
between changes of the drilling effluent indicators and changes of the seagrass standing crop.
Larger changes in drilling effluent indicators (e.g., increases in sediment Ba levels or of Ba:Fe
ratios) were associated with smaller changes in seagrass standing crop (i.e., although seagrass
-------
9-34
standing crop increased, the magnitude of the change was negatively correlated to effluent
indicators).
Both leaf biomass and leaf count increased from the pre-drilling to the during-drilling
surveys, most probably due to the growing season. However, while leaf count increased 1,212%
at the reference station, it only increased 282% and 84%, respectively, at the 4,000 m- and
1,300 m-stations (77% and 93% decreases in growth).
Impacts to the live bottom community at the 25 m station resulted primarily from burial
of cuttings. The authors concluded that smothering by drilling muds and cuttings may have been
important at distances close to the drill site. Farther from the drill site, reduction in the light
levels reaching the seafloor as a result of increased turbidity in the water column was thought to
be the primary factor.
Two follow-up surveys were conducted one year and two years after drilling. According
to the authors, these surveys indicated seagrass recovery had occurred. However, data regarding
the extent of recovery were not provided.
Boothe, P.N. andB.J. Presley. 1989. Trends in Sediment Trace Element Concentrations Around
Six Petroleum Drilling Platforms in the Northwestern Gulf of Mexico. ln_: F.R.
Englehardt, J.P. Ray, andA.H. Gillam (Eds.) Drilling Wastes. Elsevier Applied Science,
London, pp. 3-22.
The goal of this study was to determine typical concentrations of drilling fluid residuals in
surface and subsurface sediment within 500 m of six offshore drilling sites in the northwestern
Gulf of Mexico. Three types of drilling sites were studied: exploratory sites as isolated as
possible from other wells; developmental sites with multiple, recently completed wells; and
production sites where considerable time had elapsed since drilling was completed. For each of
the three types, a location was chosen in shallow water, i.e., about 30 m in depth and in deep
water, i.e., about 100 m in depth. NOTE: In the authors' use of the relative, descriptive terms
"shallow" and "deep" in their report, the term "deep" (i.e., -100 m) is not the same as the term
used in reference to this rulemaking, for which "deep" wells are defined as those in waters
greater than 1,000 m in depth.
Sediment was collected at 40 stations around each drilling site using a circularly- and
radially-symmetrical pattern. Background concentrations were determined by analyzing
sediments from 4 control stations located 3,000 m from each drilling site in addition to
subsurface sediments located well below the possible influence of surface discharges (4-31 cm
depth).
-------
9-35
Barium mass balance data show that only a fraction of the total Ba, and presumably
similar drilling mud components, are present in near-site sediments. At nearshore study sites,
approximately 94% of the discharged Ba had been transported more than 3,000 m from the
drilling sites. Offshore sites were more variable, showing transport beyond 3,000 m for 16%,
28%, and 53% of the discharged barium. Multiple regression analysis suggested excess sediment
Ba distribution was largely controlled by water depth.
The total excess Ba within 500 m of these sites was highly correlated with the total Ba
used at the site. Thus, the effect of multiple wells on near-site sediments is directly additive.
Discriminant analysis suggested that statistically significant (> twice background levels) Ba
enrichment existed in surface sediments at 25 of the 30 control (3,000 m) stations studied. Ba
levels at "control" sites were up to 4.5 times subsurface background levels. Statistically
significant elevations in sediment mercury concentrations within 125 m of the site (4-7 times
mean control levels) were observed at the Vermillion 321 and High Island sites (both deep water
sites) and were strongly correlated to Ba levels. The High Island site also showed a significant
Pb gradient, showing mean levels within 125 m 5-fold higher than controls and 3.8-fold higher
within 500 m; Pb was highly correlated with Ba at this site. Other study sites exhibited patchy
distributions of elevated sediment Pb levels, but no consistent spatial trends.
Sediment levels of Cd, Cu, and Zn were determined in only 9 or 10 surficial samples at
each site, so evaluations were tenuous with such small sample sizes. Observations made
included the following. Cd appeared elevated at the High Island and Vermillion 321 sites and
was correlated to Ba at the Vermillion site. Cu showed no consistent trend at any site except for
small elevations within 125 m at the High Island site, and was correlated to Ba. Zn showed
consistent gradients at the High Island and Vermillion 321 sites, with elevation 5-10 times
control levels, and was correlated to Ba and distance at both sites. Within 250 m of the
Vermillion 321 and High Island sites, 4- to 5-fold elevations of hydrocarbons over control station
levels were observed. However, among the six (all gas) platforms, hydrocarbon contamination
was generally low.
Continental Shelf Associates, Inc. and Barry A. Vittor and Associates, Inc. 1989a. Environmental
Monitoring in Block 132 Alabama State Waters, Summary Report. Prepared for: Shell
Offshore, Inc.
The program objective as presented in this report was to determine whether or not drilling
discharges affected the biotic assemblages living in the vicinity of the discharge site. The
program consisted of three sampling elements: 1) continuous recording of near-bottom current
speed and direction; 2) analysis of surficial sediments collected within 1,000 m of the discharge
-------
9-36
site for sediment grain size, trace metals, and oil and grease; and 3) sampling and analysis of
macroinfaunal assemblages present within 1,000 m of the discharge site.
Sampling was conducted during four surveys: Survey 1, prior to drilling discharge;
Survey 2, two months after drilling discharges commenced; Survey 3, five days after drilling
discharges ceased; Survey 4, eight months after drilling discharges ceased. The sampling pattern
consisted of eight radials centered at the discharge site and oriented toward north, northeast, east,
southeast, south, southwest, west, and northwest. Stations were located along each radial at 122
m, 500 m, and 1,000 m. In addition, four stations were located at 91 m on the four primary
radials, i.e., north, east, south, and west. The analyses conducted were: 1) sediment grain size
analyses; 2) chemical analyses; and 3) analyses of biological samples.
Near bottom currents predominantly flowed southeastward and, to a lesser extent,
northwestward. Sand predominated at many of the stations in the study area on all four surveys.
However, sediments did appear to become progressively finer as the program progressed. The
authors found that changes in sediment grain size resulting from drilling discharges could not be
easily separated from non-drilling-related changes. They concluded that changes observed within
122 m of the discharge site were probably related to drilling discharges. Changes of similar
magnitude were observed by the authors farther away, but were thought due to non-drilling-
related causes based on examination of the barium distribution.
The authors analyzed for 10 trace metals (aluminum, arsenic, barium, cadmium,
chromium, copper, iron, lead, mercury, and zinc) and oil and grease at 16 stations located within
1,000 m of the discharge site on the four surveys. Their results showed that except for barium,
the trace metal concentrations in the whole-sediment samples were correlated with the quantity
of fine-grained particles in the sediments. Their analysis of the mean concentrations of Ba in the
fine-grained fractions were shown to be consistently greater during survey 3 compared to Survey
1 at all stations located within 1,000 m of the discharge site where trace metal concentrations
were determined. During Survey 4, only one of the sixteen stations was statistically greater than
during Survey 1.
The study states that changes in other trace metals concentrations did not appear related to
drilling discharges. The concentration ranges of aluminum, arsenic, cadmium, chromium,
copper, lead, and mercury in whole sediments were within or near ranges reported in previous
studies conducted in offshore Alabama waters. The authors' statistical analysis revealed no
changes that were attributable to drilling discharges.
The authors found that the mean mercury concentrations in fine fractions during Surveys
2 and 3 were statistically greater than those observed during Surveys 1 and 4. It was concluded
-------
9-37
that mercury concentrations were not positively correlated with barium concentrations and
therefore, probably not associated with discharged barite.
At each of the four surveys, the authors collected ten replicate samples, at each of 16
stations, and analyzed them to determine the composition of the macroinfaunal assemblage. The
macroinfaunal assemblage summary parameters (number of taxa, density, diversity, evenness,
and species richness) were calculated for all stations and surveys. The values of these parameters
were within ranges expected for this area and were related to sediment grain size, but not to
proximity to the discharge site. Considerable temporal and spatial variability was observed by
the authors.
The authors used species cluster analysis and dendrograms to reflect the presence of
assemblages typical of nearshore sand and silt habitats throughout the northern Gulf of Mexico.
The authors grouped stations in the clustering analysis primarily on the basis of time of sampling,
and not by sediment texture or distance from the discharge site. Using canonical descriminant
analysis of environmental factors such as time, distance from the drill site, sediment texture, and
trace metals, they indicated that benthic station groupings were determined primarily by season
and not by distance from the discharge site or by drilling discharge tracers such as barium or
percent clay. They found that sediment texture (percent gravel) did account for a small amount
of the variability among station groups.
The study concludes that the number of macroinfaunal taxa was not related to either
sediment texture or distance from the discharge site. Individual abundance was correlated with
sediment texture and varied with season, but was not related to distance from the discharge site.
Species diversity (H') was relatively uniform temporally and spatially. The authors indicated that
the observed changes reflect the effects of sediment texture and season on numbers of
individuals, and are not related to distance from the discharge site. Evenness and species
richness levels varied with sediment texture and showed temporal changes. These parameters
were not related to distance from the discharge site.
Continental Shelf Associates, Inc. and Barry A. Vittor and Associates, Inc. 1989b. Environmental
Monitoring to Assess the Fate of Drilling Fluids Discharged into Alabama State Waters
of the Gulf of Mexico, prepared for: Offshore Operators Committee.
The purpose of this study was to determine whether drilling fluids discharged into
Alabama State Waters outside of the barrier islands can be detected in statistically significant
levels in areas of biological concern located inside the barrier islands. To accomplish this goal,
the study was divided into two monitoring efforts: area-wide monitoring and drill site
monitoring. The area-wide effort involves two principal elements: 1) sampling and analysis of
-------
9-38
surflcial sediments at 12 stations for grain size, oil and grease content, and concentrations of 10
trace metals; 2) sampling and analysis of oysters for the same metals at three of the surficial
sediment stations. The report summarizes methods and results of area-wide sampling from
Survey I (February 1986) through Survey VI (June 1988).
Beginning between Surveys IV and V, an exploratory well was drilled in Alabama State
waters Block 132. Between October 9, 1987 and February 29, 1988, approximately 7,285 m3 of
drilling fluids and 726 m3 of cuttings were discharged. About 79% of the total volume was
discharged between October 9 and November 6, 1987 (i.e., prior to Survey V).
In addition to the drilling activity, a major dredging project began during the interval
between Surveys IV and V. Dredging of the Mobile Bay ship channel began in January-February
1987, when about 500,000 m3 were dredged. Dredging resumed in October 1987 (two months
before Survey V) and was expected to continue until February 1990. About 23,000 - 31,000 m3
were dredged per day, with all of the material being placed in the offshore disposal area outside
of the barrier islands.
Also, the data set from drill site monitoring in Block 132 can aid in the interpretation of
the area-wide data set by indicating which variables might be affected by drilling discharges. For
example, if the concentration of a metal were unaffected near the drill site, then changes in the
concentration of the metal in Mobile Bay (where the nearest station is 10 km from the drill site)
could not be attributed to drilling fluids from the well.
Ba concentrations increased substantially around the drill site in Block 132 during
drilling. Statistically significant increases in Ba concentrations were detected to a distance of
500 m from the drill site, and apparent two to five-fold increases in mean Ba concentration were
evident at four 1,000 m stations (though not statistically significant).
Eleven of the 12 stations monitored in Mobile Bay during this study showed no
significant increases in fine fraction Ba concentration or barium-to-iron ratio. At Station 3, the
mean of the Survey V-VI values (318 mg/kg) was about 13% higher than the mean of the Survey
I-IV values (282 mg/kg), and was statistically significant.
This small increase in barium at Station 3 was thought probably due to natural variability
rather than drilling fluids. No significant increases were observed at four other stations located
between Station 3 and the mouth of the bay, where the drilling fluids would enter. Three of these
stations had much higher silt/clay content than Station 3 and were thought more likely to retain
fine drilling fluids deposits.
-------
9-39
Increases in concentrations of some metals other than barium occurred around the drill
site in Block 132. Changes in cadmium and mercury concentrations between surveys were
detected, but these were not attributed to drilling discharges because the changes were spatially
uniform and were not correlated with barium increases. Significant increases in arsenic (one
station), copper (one station), and zinc (one station) were detected, but were attributed to natural
sediment movement or sampling/analytical error associated with the small quantities of fine
sediment available for analysis from one station.
In the area-wide sampling, there were several significant increases in concentration and/or
metal-to-iron ratio for metals other than barium. Cadmium had the highest number of significant
differences (seven stations), followed by arsenic (four stations). Significant differences were also
detected for chromium (Station 12), and lead (Stations 3 and 9). In plots of station means, large
increases between Surveys V and VI were noted for cadmium, copper and lead at Station 3, and
copper at Station 9. The copper increases were not significant in the statistical analysis, which
used the mean of Surveys V-VI.
Increases in concentrations of these other metals were thought probably not due to
drilling fluids. All of the metals except aluminum and iron, which are normally associated with
clay particles, are present in drilling fluids primarily as trace contaminants of barite. Because
barium is more concentrated in drilling fluids (relative to normal sediments) than the other
metals, increases in these other metals due to drilling fluids were expected to be accompanied by
major increases in Ba. No such increases were seen during the study.
Oil and grease concentrations increased significantly at Stations 2, 5, 6, 7, 8, and 11
between Surveys n-IV and Surveys V-VI. The increase at Station 11 can be attributed to an
increase in silt/clay content of the sediments (oil and grease concentrations tended to be higher in
sediments containing more silt/clay). The explanation for the other increases were not known,
but were thought probably not due to drilling fluids, because there were no accompanying
increases in barium concentration.
Drilling fluids discharged to the ocean may contain small amounts of hydrocarbons,
although they are subject to the test of "no visible sheen". At stations around the drill site in
Block 132, there were some apparent increases in sediment oil and grease content during drilling,
but these appeared to be related to natural sediment changes as indicated by whole sediment
aluminum concentrations.
There were no statistically significant increases in the concentrations of 8 and 9 metals in
oyster tissue. Arsenic concentrations in both depurated and non-depurated oysters were
significantly higher on Surveys V-VI than on Surveys I-IV. The temporary increase in arsenic
-------
9-40
concentration in oyster tissue probably is not due to drilling fluids. There are no oyster data from
the drill site monitoring in Block 132, because no oysters were present there. However, arsenic
concentrations in drilling fluid were no higher than those in the fine fraction of sediments from
Mobile Bay. The reason for the temporary increase in arsenic concentrations in oysters is not
known.
A statistical difference between Surveys V-VI and Surveys I-IV does not necessarily
indicate an effect of drilling. Some significant differences could reflect natural changes that did
not occur during the previous year of "baseline" sampling. Other differences could be due to the
channel dredging project, which began between Surveys IV and V and which continued through
the monitoring program. Unfortunately, conditions in the real world are seldom ideal in the
sense of a controlled experiment.
The reason for increases in metal concentrations between Surveys I-IV and Surveys V-VI
was not known. Possible explanations included the following:
• The first four surveys did not encompass the full range of non-drilling related variations
in trace metal concentrations. Such variations may be attributed in part to natural
seasonal and year-to-year fluctuations.
• The channel dredging project.
• The fine fraction at predominantly sandy stations may be different from the fine fraction
at silt/clay stations, or more prone to analytical error; stations with high percentages of
sand had highly variable metal concentrations or metal-to-iron ratios on one or more
surveys and support this hypothesis.
Continental Shelf Associates, Inc. 1989. Pre-drilling and Post-drilling Surveys for Pensacola
Area Block 996. Prepared for Texaco Producing Inc.
A monitoring study of a single exploratory well located in approximately 60 m water
depth was conducted in Pensacola Block 996 to detect any obvious impacts to the hard bottom
epibiotic community of nearby live-bottom areas. The study involved collected pre-drilling and
post-drilling video and quantitative still camera data, as well as post-drilling surface sediment
chemistry data. Drill site sediment Ba levels at 3 stations within 250 m of the discharge,
expressed as either bulk phase or fine-fraction values, were 40-125 times greater than the average
reference station value (which in turn was about twice the reported background level). Sediment
barium levels (bulk and fine fraction) at 2000 m averaged twice the reference station levels.
Bulk phase sediment chromium levels were only elevated at the drill site; fine-fraction chromium
levels were 50% and 20% above reference levels at 250 m and 500 m, respectively.
-------
9-41
Background was defined at three reference stations located approximately 3,500 m from
the drill site. However, reference station values must be regarded with caution for three reasons:
1) predrilling samples were not taken, 2) values obtained in the post-drilling survey (45-70 ppm
Ba; 19-22 ppm Cr) were substantially higher than an earlier, nearby baseline conducted prior to
drilling (29 ppm Ba; 3 ppm Cr), and 3) a continuous distance-dependent decrease in bulk and
fine-fraction Ba and fine-fraction Cr occurred to the farthest radial array stations, including the
reference stations.
Only "catastrophic, large-scale changes (e.g., complete mortality)" would be detectable
from the photographic and video data collected. No such "catastrophic" effects were observed.
Overall, photographic data from stations within 2,000 m of the drill site showed a 55% decrease
in total biotic coverage for pre- versus post-drilling surveys; reference station values decreased
19%. Overall decreases, at both drill site and reference stations, were primarily due to dramatic
(i.e., 95%) decreases in bryozoan coverage between surveys.
This study presents a typical picture of what exploratory well impacts will be on sediment
chemistry. The significant confounding factor here is the "true" background level of Ba and Cr.
If the earlier study values are used as reference values, then sediment Ba levels are elevated four-
fold at 2 km, and sediment Cr values are 8- to 10-fold higher within 500 m of the discharge. This
range of values is expected for these types of discharges.
Steinhauer, M. et al. 1990. California OCS Phase IIMonitoring Program Year-Three Annual
Report. Chapter 13. Program Synthesis and Recommendations.
The California Outer Continental Shelf (OCS) Phase II Monitoring Program (CAMP)
study is a good example of the difficulties inherent to marine impact assessment. The specific
objectives of CAMP were:
• To detect and measure potential long-term (or short-term) chemical, physical, and
biological changes in the benthic environment around development platforms in areas of
soft-bottom and hard-bottom substrates in the southern Santa Maria Basin.
• To determine whether the changes observed were caused by drilling-related activities or
whether they were the product of natural physical, chemical, and biological processes in
the study area.
The study area is on the southern portion of the Santa Maria Basin OCS. All but one
station were located at water depths ranging from 90 m to 410 m. At the soft-bottom site, a
semi-radial array of stations was located around the proposed future site of Platform Julius in
water depths raging from 123 m to 169 m. At the hard-bottom site, stations were located on
-------
9-42
high- and low-relief hard features, and in adjacent soft-sediment locations in 105 m to 213 m of
water near the site of Platform Hidalgo.
In the development of CAMP, its design explicitly addressed the importance of taking
synoptic measurements from replicate samples and keeping replicate data separate. Also, in the
absence of pre-impact sampling it could be argued that control sites and impacted sites always
differed and, in the absence of control sites, it could be argued that change at impacted sites was
not caused by the impact. CAMP's design also employed an optimal-impact study design, with
pre-impact as well as post-impact sampling, and control site as well as impacted site sampling.
Postponement of platform emplacement and drilling at the soft-bottom site and an
abbreviated drilling schedule at the hard-bottom site necessitated changes in the scope and
schedule of the monitoring program. Monitoring at the soft-bottom site was thought to provide
valuable baseline information on physical, chemical, and biological features and processes in the
area. This information was thought to be valuable in the design and execution of future
monitoring studies of platform discharges when the platform is installed at the Julius site.
Although the soft-bottom components of the monitoring program were prematurely
concluded due to a lack of industry activity, certain aspects of the monitoring design were
believed useful. Biological data supported the idea that meaningful levels of change could be
detected for dominant species and for more encompassing parameters such as diversity.
Chemical data supported the idea that barium could be used as a tracer of activity in spite of high,
but invariate, natural levels in the region.
Data representing different sampling occasions provided evidence of significant temporal
variation in both the macrofauna and meiofauna. Within-year variations, although significant,
did not follow the same patterns consistently from one year to the next. Nevertheless, these
results were taken to demonstrate the importance of conducting repeated sampling before and
after initiation of drilling activities, to provide a basis for differentiating between natural
temporal variations in benthic community parameters and impacts caused by drilling and
production activities.
Monitoring at the hard-bottom site near Platform Hidalgo provided information on
platform effects and on discharges associated with drilling of seven wells between November
1987 and January 1989. The original hypothesis for determining platform-related effects
established two major criteria: 1) a before-and-after farfield/nearfield effect (i.e., space-time
interaction) and 2) a change in organism abundance correlated to the dose of drilling wastes
(relative flux of chemical signals, from sediment trap data). Of the 10 species tested for a time-
space interaction, only the solitary coral, Caryophyllia sp., showed such an effect. Due to an
-------
9-43
incomplete data set from the sediment trap fluxes at the three stations where a significant time-
space interaction was observed for this species, data are only available for a limited period
(November 1987 and October 1988).
There were insufficient number of stations to calculate an analysis of variance with depth
and time as additional covariates. Given these limitations, together with those of limited data
from the sediment traps, the best test of a platform-related effect on Caryophyllia were scatter
diagrams. Neither total sediment flux nor total PAH concentrations were related to the effect,
although in both cases one station that showed a loss of Caryophyllia cover between 1987 and
1988 had a slightly greater relative flux of these materials. However, tests of the relationship
between Caryophyllia sp. abundance in a larger data set indicated a highly significant
relationship between sediment flux and species abundance.
These data would seem to support a hypothesis of impact. However, the authors
presented a disturbing analysis. Although the change in percent cover of Caryophyllia seems to
support a conclusion of drilling-related impacts, it was noted that the change between sampling
periods was less than 50 percent, the original power analysis indicated that, with a sampling
replication of 60 photo-quadrants per station per time, the minimum change in the density of this
species that could be detected with 95 percent confidence for 80 percent of the time was
approximately 70 percent. This power analysis-to-effect comparison raises questions as to
whether this effect in a single species was a chance event. The sampling error was greater than
the range of the effect detected. Therefore, despite the time-space interaction and a relationship
between dose and response, the authors concluded that significant doubts remain as to whether
there was a real platform-related effect on this species.
CAMP monitoring data has revealed several variables that may limit the ability of any
monitoring program to detect change related to oil and gas activity in the region. The densities
and numbers of species with transect location has been shown to vary along all isobaths.
Potential sources of hydrocarbons from natural seeps confound the ability to relate change to oil
and gas activities. Fishing activities risk in-situ instrument deployments and also affect bottom
communities. Finally, the difficulty of scheduling surveys to coincide with drilling activities for
appropriate before-and-after comparisons is a basic problem in any monitoring program, and it
has been shown in this program to be particularly difficult to control.
-------
9-44
9.3.2 Synthetic-Based Fluids
Smith, J. and S.J. May. 1991. Ula Wellsite 7/12-9 Environmental Survey 1991. A report to
SINTEF SI from the Field Studies Council Research Centre. November 1991.
This paper is the second in a series of three lead by Janet Smith, identifying the results of
yearly sampling at the Ula well site 7/12-9 in the North Sea. This paper also includes a
comparison of the 1990 to 1991 results. The authors report that sampling was conducted one
year after the discharge of an ester-based drilling fluid. The sample stations were along two
transects, one to the southwest (SW) and one to the southeast (SE), with distances from the
discharge location of 50, 100, 200, 500, 800, 1,200, 2,500, and 5,000 m to the SW and 100, 200,
500, and 1,200 m to the SE. A reference station was located 6,000 m to the northwest of the
discharge point. The ten replicate samples taken at this reference station were "treated as two
sets of five replicates to make data analysis easier," and are referred to as Ref A and Ref B.
Samples were taken for total hydrocarbon (THC), ester, metals, grain size analysis, and
biological analysis.
THC reported for the 1990 samples were highest at 200 and 500 m to the SW and 100
and 200 m to the SE. These THC levels were reported at 774 and 86.4 mg/kg for the SW stations
and 184 and 205 mg/kg for the SE stations, respectively. The THC levels for the 1991 survey
were dramatically reduced to 13.6, 5.9, 64.0, and 3.8 mg/kg for same stations listed above.
Although there was an increase in THC levels for the 50 and 100 m SW stations, it was not
above background levels measured at the reference station. There was an overall decreasing
trend for the THC concentration from 1990 to 1991.
The ester concentrations reported in 1990 were 85,300, 46,400, and 208 mg/kg for the 50,
100, and 200 m SW stations, respectively. The reported ester values for these stations for 1991
dropped to 0.21, 0.22, and 1.34 mg/kg, respectively.
Barium concentrations for 1990 were reported highest at the 50-200 m SW and 100-200
m SE stations. There was an increase in Ba concentration along the SW transect from 1,720 to
2,890 mg/kg, out to 200 m. The Ba concentration decreased along the SE transect, with the
highest level of 3,770 mg/kg at 100 m. There was an overall decrease in 1991 Ba levels.
The authors also report dramatic changes in the benthic communities from 1990 to 1991
as summarized in Exhibit 9-7. Although one station showed an increased abundance of the
opportunistic C. capitata, this isolated instance of taxonomic indicator of stress was not taken to
demonstrate any generalized impact had occurred from the discharge of this material.
-------
9-45
Exhibit 9-7. 1990 and 1991 North Sea Benthic Community Data
Sample Station
50mSW
100 m SW
100 mSE
Reference A
Reference B
Taxa
1990
4
7
35
66
53
1991
51
44
52
48
58
Individuals
1990
16
167
234
385
356
1991
379
370
405
340
329
Candler, JohnE., S. Hoskin, M. Churan, C.W. Lai, andM. Freeman. 1995. Sea-floor
Monitoring for Synthetic-Based Mud Discharged in the Western Gulf of Mexico. SPE
29694 Society of Petroleum Engineers Inc. March 1995.
The authors monitored the fate and effects of discharged SBF and associated cuttings
(SBF-cuttings). The authors measured the fate of the polyalphaolefin (PAO) on three sampling
cruises to an oil platform that had discharged SBF-cuttings consisting of 441 bbl of cuttings and
354 bbl of adhering SBF. The cruises were conducted nine days, eight months, and 24 months
after the discharge had stopped. The effects of the SBF and cuttings on the benthos were
measured only on the third sampling cruise. The sampling grid was a series of stations along two
perpendicular transects running in north/south and east/west directions from the discharge point.
The sampling stations were located along each of the transects at distances of 25 m, 50 m, 100 m,
and 200 m from the discharge point. Samples from 2,000 m were used as reference points. The
authors used chemical analysis for barium, total petroleum hydrocarbons (TPH) and oil and
grease (O&G) to determine the presence of PAO base fluid in sediment samples. The authors
stated that TPH was the better of the two organic analyses for detecting the synthetic material
because the TPH test excludes certain polar organic compounds (e.g., fatty matter from animal
and vegetable sources) often detected in O&G tests. Effects on the benthos were determined by a
community analysis system which measured the species richness (number of taxa), evenness
(how equally the total number of organisms is distributed), and diversity (measure of interaction
of richness and evenness).
The authors indicated that the greatest initial distribution of TPH, as measured nine days
after discharge, was along the north/south transect with maximum values of 39,470 mg/kg (3.9
percent) at 100-m north and 134,428 mg/kg (13.4 percent) at 50-m south. In addition, TPH was
initially measured above 1,000 mg/kg in all four directions with the furthest locations of 100-m
south and 200-m north. The results from the second sampling survey (eight months later)
indicated a decrease in average TPH for all distances except at 25 m. There was an increase in
average TPH at 25 m predominately to the south and west (from 203 to 7,283 and 2,827 to
-------
9-46
25,747 mg/kg, respectively), indicating a southwesterly drift in the sediment. Results from the
third and final sampling survey (24 months later), while indicating a decrease in the average TPH
at 25 m, also indicated an increase in TPH at all but one of the four 25-m stations. The decrease
of the west 25-m station (from 25,747 to 8,330 mg/kg) overshadowed the increase of TPH at the
other three stations. Two stations beyond 25 m (50-m south and west) each measured an increase
to greater than 1,000 mg/kg TPH.
Although not discussed by the authors, the chemical analysis for the third survey
indicated an increase or no change in TPH for 10 of the 16 stations within 200 m of the
discharge. There was a slight increase in TPH for the 2,000-m west reference station. Sediment
TPH and barium data suggest little degradation of PAO (as indicated by TPH) between the
second and third surveys, although migration of fluids to further stations may be occurring.
Exhibits 9-8 and 9-9 present average PAO (as indicated by TPH) and Ba levels versus distance
for these surveys.
The benthic analysis, at 24 months after SBF-cuttings discharge terminated, indicated
three sample stations that were significantly different than the reference stations. These three
sample stations were 25- and 50-m south and 25-m west from the discharge location. The
highest TPH values were also measured at these three stations. The variability for species
richness, abundance, diversity, and evenness was reported to be much higher among all sample
stations within 200 meters of the discharge site than the variability among the reference stations.
Schaanning, M. 1995. Evaluation of Overall Marine Impact of the Novadril Mud System. NIVA
Report 0-95018.
This report reviews available laboratory data on the toxicity, bioaccumulation, and
biodegradability of three types of polyalphaolefm (PAO)-based SBF. The report compares the
finding of experimental studies on PAOs to field surveys of ester- and ether-based synthetic
muds. The author cites results of Smith and Moore (1990) and Smith and Hobbs (1993), in
which three surveys were conducted at the Ula well site 7/12-9 in the North Sea in 1990
immediately after discharge of 97 tons of synthetic esters ceased, in 1991 one year later, and in
1992 two years later. Sampling pattern information for these surveys is given in the summary of
Smith and May (1991).
Schaanning reports that during the 1990 survey, the maximum concentration of synthetic
ester detected was 85,300 mg/kg at 50 m from the well. The average concentration of synthetic
ester for eight sample sites (between 0 and 1 km; no further detail provided) was 16,546 mg/kg
compared to 2.3 mg/kg at a reference station 5,000 meters distant. Benthic organisms were
severely impacted out to 100 m. Schaanning reports that in 1991 and 1992, the maximum
-------
Exhibit 9-8. Sediment TPH vs. Distance from Drill Site
9-47
Distance from Drill Site (meters)
Exhibit 9-9. Sediment Barium vs. Distance from Drill Site
-------
9-48
concentrations of synthetic ester base fluid were 11.7 and 0.38 mg/kg, respectively. In 1991, the
average ester concentration at eight stations within 1,000 m of the drill site was 2.5 mg/kg,
approximately 10-fold higher than that at a reference station 6,000 m distant from the drill site.
In 1992, the average ester concentration at eight stations within 1,000 m was 0.24 mg/kg,
approximately 3-fold higher than at the reference station 6,000 m distant. Schaanning reports
other multivariate analyses of benthos (Smith and Hobbs, 1993) provided evidence that minor
changes to the macrobenthic communities were still present two years after the discharge ceased.
Schaanning also cites a three-year study by Bakke et al. (1992) of a discharge of cuttings
contaminated with an ether-based SBF. The surveys were conducted at the Gyda well site 2/1-9,
just after the discharge of 160 tons of ether SBF ceased and annually for the next two years.
Bakke reports that the maximum concentrations of synthetic ether at 50 m southwest from the
platform were 2,600, 14,700, and 3.7 mg/kg for 1991, 1992, and 1993, respectively. The mean
concentrations for the stations between 100 and 200 m from the platform for 1991, 1992, and
1993 were 236, 96, and 2.1 mg/kg ether, respectively. Although no benthic data are presented for
the four stations at which benthic biota were analyzed, Bakke reports benthic impacts were
"remarkably weak" for the high concentration of synthetic ether detected in 1992.
It should be noted that Schaanning includes brief discussions of additional seabed studies,
which are not referenced to studies or reports, from the North Sea. The information presented
from these studies is limited and does not include any quantitative results from benthic analyses.
Daan, R., K. Booij, M. Mulder, andE. Van Weerlee. 1996. Environmental Effects of a
Discharge of Cuttings Contaminated with Ester-Based Drilling Muds in the North Sea,
Environmental Toxicology and Chemistry, Vol. 15, No. 10, pp. 1709-1722. April 9, 1996.
The authors conducted field surveys in the Dutch sector of the North Sea for the effects of
discharged drill cuttings contaminated with an ester-based fluid over an 11-month period. A total
of 181 metric tons of ester (in a total estimated amount of 477 tons of an ester-based SBF) was
discharged. Three sampling surveys were conducted 1, 4, and 11 months after the drilling was
completed. The authors also conducted a background survey prior to drilling to determine
natural variations of macrofauna and background chemistry. This background survey was
conducted prior to platform placement along a northeast-southwest transect that followed local
residual current patterns, with station located from the well site at distances of 75, 200, 500,
1,000, and 3,000 m to the NE, and 75 m to the SW. However, because of the changes in
sediment type beyond 200 m, this transect was not used in the post-drilling surveys. The first
post-drilling survey was conducted one month after ester-based SBF discharges ceased to
determine ester base fluid concentrations only and was sampled northward from the drill site at
distances of 75, 125, and 200 m to the N, then 75 m to the NE of the well site. There were no
-------
9-49
benthos samples taken during this survey. The second and third post-drilling surveys occurred
four and 11 months after ester-based SBF discharges ceased. Both surveys included benthos and
chemistry samples taken at 75, 125, 200, 500, 1,000, and 3,000 m to the N, at 75, 125, and 200 m
to the NE, and at 75 m to the SW.
The chemical analysis for the three post-drilling surveys indicated the ester base fluid was
confined to distances under 200 m from the well site. Once beyond the 200 m station, ester base
fluid concentrations were at background levels. However, the analysis also showed an increase
in the ester base fluid from the one- to four-month surveys for all distances out to 200 m.
Analyses from the 11-month survey indicated a sharp decline in ester base fluid at all stations.
Sediment grain size distributions and benthic macrofaunal abundance from the
background survey indicated similar communities occurred only out to 200 m. As a result,
benthos background results used for analysis were limited to stations at 75, 125, and 200 m from
the discharge location. The benthic analysis from the second survey indicated effects out to
500 m from the well site and was attributed to the echinoderm Echinocardium cor datum.
Ecordatum is highly sensitive to organic enrichment and living adults were found up to 500 m
from the well site. Additionally, a bivalve that was one of the dominant species at 500 m was not
found at the closer stations. There was a gradual increase in species abundance with distance.
When compared to the background levels, the species abundance beyond 500 m after four
months was lower, but the authors attributed this to seasonal fluctuations. Benthos analysis from
the third post-drilling survey at 11 months indicated significant impacts out to 200 m. The
authors indicate that species abundance, while significantly different from the reference stations,
showed recovery of the sediments was apparent after 11 months.
BP Exploration Operating Company Ltd. 1996. BP Single well 15/20b-12 (Donan) synthetic
mud (Petrofree) second post-drilling environmental survey. Environment & Technology
Ltd. ERTDraft Report No. 96/062/3 June 1996.
This survey was the second of two surveys at the BP single well site 15/20b-12, located in
the North Sea. Although the first survey was not available for review, this second report
compared the 1995 and 1996 seabed survey results for this well site. The first survey was
conducted in August 1995 approximately 5 months after drilling shutdown. The second survey
was conducted in June 1996, 15 months after drilling shut down. The discharge of Petrofree, an
ester SBF, amounted to 304 metric tons and was discharged at a depth of 142 m. The
observations taken by the authors were: 1) Side-scan sonar for cutting depth (piles), 2) Petrofree
base fluid concentrations in 0-2 cm, 2-5 cm, and 5-10 cm of sediment, 3) barium concentrations,
4) redox measurements at 2 cm and 4 cm, and 5) biota . Sampling sites were at 25-5,000 m
-------
9-50
down-current (South) from the platform, 25-200 m up-current to the North, and 25-100 m to the
East, West, Northeast, Northwest, and Southwest.
The 1995 survey indicated the highest concentration of Petrofree in the surface sediment
(0-2 cm) was located within 25 meters of the platform. The sampling point with the highest
concentration was 25 m Southwest, with an ester concentration of 8,389 mg/kg. Concentrations
within 25 meters of the platform ranged from 1,055 to 8,389 mg/kg. The highest concentration at
the furthermost station was 105.5 mg/kg at 200 meters north of the platform. The concentrations
of Petrofree (base fluid) within 2-5 cm of sediment within 25 m ranged from 8.4 to 1,935 mg/kg.
The concentrations of Petrofree within 5-10 cm of sediment within 25 m ranged from 0.9 to
105.3 mg/kg. Petrofree was measured at a concentration of 1,081 mg/kg in 10-15 cm subsurface
sediment at 25 meters north. Barium concentration ranged from 70,100 mg/kg at the center to
661 mg/kg at 1,200 m south. Redox and side-scan sonar results for 1995 were not reported.
Although data are not given for effects on benthic communities for the 1995 survey, the report
indicated that the number of species, evenness, and diversity were statistically significant in
relation to Petrofree concentration and distance.
The 1996 survey indicated lower concentrations for surface sediment (0-2 cm) for most
sample sites. The authors reported changes ranging from 1.1-fold lower concentrations to 13.5-
fold lower concentrations from 1995 to 1996. Sediment concentration of Petrofree ranged from
133.1 to 1,785 mg/kg for the 25 m range. The highest concentration at the furthermost point was
0.1 mg/kg measured at 500 m south. Variability among subsurface sediment (2-5 and 5-10 cm)
Petrofree concentrations prevented development of trends for subsurface concentrations. Barium
concentration ranged from 22,000 at the center to 572 mg/kg at 1,200 m south. Redox readings
indicated anaerobic conditions within 200 meters of the platform. The depth profile indicated
cutting piles of up to 15 cm out to 50 meters from the platform. Biota measurements indicated
clear impacts at 50 m, with transition communities developing between 100 to 300 m. The
authors stated the benthic communities at 1,200 meters indicated impacts associated with
industrial activity and trace amounts of Petrofree were measured at that location.
Vik, E.A., S. Dempsey, B. Nesgard. 1996. Evaluation of Available Test Results from
Environmental Studies of Synthetic Based Drilling Muds. OLF Project, Acceptance
Criteria for Drilling Fluids. Aquateam Report No. 96-010.
The authors provided a summary of results from eleven seabed studies, three of which
have been separately reviewed in this report. Many of these reports were unavailable in English.
The authors presented a short review of sampling grids, discharge volumes, discharge depths, and
results. The information provided by authors was limited for each seabed survey and the results
are included in Exhibit 9-2. However, a critical review of each original report has not been
-------
9-51
provided in this Environmental Assessment. The overall trends of these reports were: (1)
concentrations decreased with distance from discharge point; (2) concentrations measured were
not discharge volume dependent; and (3) concentrations decreased with time, although there
were a few instances where the concentrations actually increased.
Continental Shelf Associates, Inc. 1998. Joint EPA/Industry Screening Survey to Assess the
Deposition of Drill Cuttings and Associated Synthetic Based Mud on the Seabed of the
Louisiana Continental Shelf, Gulf of Mexico. 21 October 1998, Data Report. Prepared
for API Health and Environmental Sciences Dept.
The authors provided a data report on a joint EPA/Industry screening cruise, which was
conducted to provide a preliminary evaluation of the areal extent of observable physical,
chemical, and biological impacts of drill cuttings contaminated with SBFs (SBF-cuttings) and to
evaluate sampling methods that will be used in future more detailed surveys. Three sites were
surveyed for organics (SBF associated hydrocarbons, TOC and PAH), sediment grain size, odor
and visual characteristics, and water column profiles. Oxidation-reduction potential, macrofauna
and sediment toxicity samples were taken at selected sites. Side-scan sonar and Benthos
MiniROVER remote operated vehicle (ROV) television camera were used to identify
accumulation of drill cuttings. Sampling sites were located on a radial grid and along four
transects that were parallel with bathymetry when possible. The stations were at distances of 50,
150, and 2000 m from the platform, with the 2000 m stations serving as the references stations.
Two additional stations, 100 m from the platform, were sampled at two of the sites. The highest
concentration of SBF associated hydrocarbons (1,900, 6,500, and 23,000 mg hydrocarbon/kg dry
sediment) were found within 50 m of the platforms. The furthermost station at which SBF-
associated hydrocarbons were found was 100 m for one platform. The concentration measured at
that one station was 41 mg hydrocarbons/kg dry sediment. Nine sediment samples were also
taken for sediment toxicity tests using the 10-day sediment toxicity test (ASTM E 1367-92;
ASTM, 1992). Two of the nine sediment samples taken would have been considered toxic to
marine amphipods using the current sediment testing guidelines. Percent survival of amphipods
exposed to those two samples was 77% and 62%. SBF associated hydrocarbons were not
measurable at the detection level for these two samples. Analyses of impacts to marcofauna were
not complete at the time of this report. Conclusions drawn by the authors were elevated
concentrations of SBF-associated hydrocarbons were scattered around the platform rather than in
a continuous pattern; side-scan techniques could be improved; ROV use is not appropriate near
soft muddy seafloors; and a better methodology for evaluating electrochemical potential (Eh) is
needed.
-------
9-52
EPA also gathered samples for duplicating testing, and is also holding samples for
macrofaunal enumeration. EPA has not yet completed its analyses and evaluation. EPA intends
to complete this work and report the results in the future.
LGL Ecological Research Associates, Inc., 1998. Opportunistic Sampling at a Synthetic Drilling
Fluid Discharge Site on the Continental Slope of the Northern Gulf of Mexico: the
Pompano Development, 10-11 July 1997 and 13-14 March 1998. Prepared for BP
Exploration, Inc.
The authors conducted two benthic studies to assess the impacts of the discharge of drill
cuttings contaminated with the SBF Petrofree LE (a 90% LAO/10% ester blend) on benthic
communities in 565 meters water depth. The studies were conducted 9 months apart with the
first (July 1997) conducted 4 months after discharge ceased. Prior to this July survey, 6,263 bbls
of SBF had been discharged. An additional 1,486 bbls of SBF was discharged for 2 months prior
to the second survey in March of 1998. The surveys analyzed benthic sediment samples for both
chemical concentrations of Petrofree LE and changes in benthic communities along four transects
(NE, SE, SW, and NW). Sampling stations were located at 25 m intervals with the SW and NE
transects extending to 75 m and the NW and SE transects extending to 50 m. As a result of
chemical analyses from the July 1997 survey, the NW transect was extended to 90 m during the
March 1998 survey. Samples for chemical analysis were divided into surficial samples (0-2 cm)
and subsurface samples (2-5 cm).
Chemical analyses results for both surveys indicate the highest concentration of SBF for
both surficial and subsurface samples were found along the NE transect and were located at the
75 m station. Concentrations of SBF at this location for the surface samples were 165,051 mg/kg
for 1997 and 198,320 mg/kg for 1998. Concentrations at these locations for subsurface samples
were 8,332 mg/kg for 1997 and 85,821 mg/kg for 1998. The authors suggest the possible reasons
for high concentrations of SBF may be due to slower biodegradation rates than those noted in the
North Sea or the initial concentration of Petrofree LE was higher than that measured. There were
no statistical differences between the July 1997 and March 1998 surficial and subsurface
concentrations. However, the March 1998 values were higher, lending some weight to the
hypothesis that the initial Petrofree LE concentration was higher than measured.
Results of the March 1998 benthic survey indicate an increase of polychaetes and
gastropods as compared to MMS background data. Polychaete densities were nearly 40 times
higher than background data. Gastropod densities were nearly 3,000 times higher than
background. The authors postulated that biodegradation may have sustained bacterial activity at
a level that lead to an increase in these benthic macrofauna.
-------
10-1
10. BIBLIOGRAPHY
Addy, J.M., J.P. Hartley and P.J.C. Tibbetts. 1984. Ecological effects of low toxicity oil-based
mud drilling in the Beatrice Oilfield. Marine Pollution Bulletin, Vol. 15, No. 12. pp. 429-
436.
Alaska Administrative Code (AAC) Title 18. Environmental Conservation, Chapter 70 - Water
Quality Standards and Chapter 80 - Drinking Water.
Alaska Department of Fish and Game. 1998. Fax transmission from M. Beverage; AK Rule 2-
S-H-11-96 and 5 AAC 31.390. December 10, 1998.
American Society of Testing and Materials (ASTM). 1992. Standard Guide for Conducting 10-
day Static Sediment Toxicity Tests with Marine and Estuarine Amphipods. ASTM. 26 pp.
American Petroleum Institute (API). 1998. Responses to Technical Questions for Oil and Gas
Exploration and Production Industry Representatives. E-mail from M. Parker, Exxon to J.
Daly, U.S. EPA/OW with attached file, August 7, 1998.
API. 1995. Reducing Uncertainly in Laboratory Sediment Toxicity Tests. API Publication
4632. Health and Environmental Sciences Department. September 1995.
Aquaplan-NIVA. 1996. Environmental Monitoring Survey of the Ekofisk Centre and Eldfisk
2/7 B Fields, May 1995. Prepared for Phillips Petroleum Company Norway. Cited in Vik,
E.A., S. Dempsey, and B.S. Nesgard. 1996. OLF Project Acceptance Criteria for Drilling
Fluids, Evaluation of Available Test Results from Environmental Studies of Synthetic
Based Drill Muds. Aquateam-Norwegian Water Technology Centre A/S Report No. 96-
010.
Avanti Corporation. 1996. Ocean Discharge Criteria Evaluation for the NPDES General Permit
for the Eastern Gulf of Mexico OCS. Draft submitted to EPA Region 4. May 20, 1996.
Avanti Corporation. 1993. Environmental Analysis of the Final Effluent Guideline, Offshore
Subcategory, Oil and Gas Industry. Volume I - Modeled Impacts. Prepared for the U.S.
Environmental Protection Agency, Office of Science and Technology. January 14, 1993.
Barsky, C. 1998. Telecommunication with C. Barsky, California Fish and Game by R.
Montgomery, The Pechan-Avanti Group. November 20, 1998.
Berge, J.A. 1996. The effect of treated drill cuttings on benthic recruitment and community
structure: main results of an experimental study on a natural seabed In: The Physical and
Biological Effects of Processed Oily Drill Cuttings. E&P Forum Report No. 2.61/202.
April 1996. pp. 41-63.
-------
10-2
Beverage, M. 1998. Telecommunication with M. Beverage, Alaska Department of Fish and
Game, by R. Montgomery, The Pechan-Avanti Group. December 9, 1998.
Boothe, P.N. and BJ. Presley. 1989. Trends in sediment trace concentrations around six
petroleum drilling platforms in the northwest Gulf of Mexico. In: F.R. Englehardt, J.P.
Ray and A.H. Gillam (Eds.) Drilling Wastes. Elsevier Applied Science, London, pp. 3-22.
Bothner, M.H. et al. 1985. The Georges Bank Monitoring Program 1985: Analysis of Trace
Metals. U.S. Geological Survey Circular 988.
Boyd, P. A., D.L. Whitfill, T.S. Carter and J.P. Allamon. 1985. New Base Oil Used in Low-
Toxicity Oil Muds. J. Petroleum Technology, January 1985, pp. 137-142
Brandsma, M.G. 1996. Computer simulations of oil-based mud cuttings discharges in the North
Sea. In: The Physical and Biological Effects of Processed Oily Drill Cuttings. E&P
Forum Report No. 2.61/202. April 1996. pp. 25-40.
BP Exploration Operating Company Ltd. 1996. BP Single well 15/20b-12 (Donan) synthetic
mud (Petrofree) second post-drilling environmental survey. Environment & Technology
Ltd. ERT Draft Report No. 96/062/3 June 1996.
California Department of Fish and Game (CA DFG). 1998. Commercial Landings for 1997,
Table 15. Supplied by J. Robertson, CADFG. December 10, 1998.
Candler, J., R. Herbert and A.J.J. Leuterman. 1997. Effectiveness of a 10-day ASTM Amphipod
Sediment Test to Screen Drilling Mud Base Fluids for Benthic Toxicity. SPE 37890
Society of Petroleum Engineers Inc. March 1997. 19 pp.
Candler, J.E., S. Hoskin, M. Churan, C.W. Lai and M. Freeman. 1995. Sea-floor Monitoring for
Synthetic-Based Mud Discharged in the Western Gulf of Mexico. SPE 29694 Society of
Petroleum Engineers Inc. March 1995.
Candler, J., J.H. Rushing and A.J.J. Leuterman. 1993. Synthetic-Based Mud Systems Offer
Environmental Benefits Over Traditional Mud Systems. SPE 25993 Society of Petroleum
Engineers Inc. March 1993. pp. 485-499.
Churan, M., J.E. Candler and M. Freeman. Onsite and Offsite Monitoring of Synthetic-Based
Drilling Fluids for Oil Contamination. SPE 37906 Society of Petroleum Engineers Inc.
March 1997. 14pp.
Continental Shelf Associates, Inc. 1998. Joint EPA/Industry Screening Survey to Assess the
Deposition of Drill Cuttings and Associated Synthetic Based Mud on the Seabed of the
Louisiana Continental Shelf, Gulf of Mexico. Draft Data Report, Prepared for API Health
and Environmental Sciences Dept.
-------
10-3
Continental Shelf Associates, Inc. 1990. Environmental Monitoring Program for Exploratory
Well #1, Lease OCS-G 6264 High Island Area, South Extension, East Addition, Block A-
401 Near the West Flower Garden Bank. Prepared for Union Oil Company of California,
Houston, TX. 36 pp. + app.
Continental Shelf Associates, Inc. 1989. Pre-Drilling and Post-Drilling Surveys for Pensacola
Area Block 996. Prepared for Texaco Producing Inc. 38 pp. + app.
Continental Shelf Associates, Inc. and Barry A. Vittor and Associates, Inc. 1989a. Environmental
Monitoring in Block 132 Alabama State Waters, Summary Report. Prepared for Shell
Offshore, Inc. 78 pp.
Continental Shelf Associates, Inc. and Barry A. Vittor and Associates, Inc. 1989b.
Environmental Monitoring to Assess the Fate of Drilling Fluids Discharged into Alabama
State Waters of the Gulf of Mexico. Prepared for Offshore Operators Committee. 46 pp +
app.
Continental Shelf Associates, Inc. 1988. Monitoring of Drillsite A in the Gainesville Area
Block 707. Prepared for Sohio Petroleum Company, Houston, TX, April 26, 1988. 124
pp.
Continental Shelf Associates, Inc. 1986. Environmental Monitoring Program for Exploratory
Well No. 1, Lease OCS-G 6613, West Cameron Area Block 663. Prepared for Texaco
U.S.A. 72pp + app.
Continental Shelf Associates, Inc. 1986. Environmental Monitoring Program for Exploratory
Well No. 1, Lease OCS-G 6281, East Breaks Area Block 166 Near Applebaum Bank.
Prepared for Texaco U.S.A. 92pp.
Continental Shelf Associates, Inc. 1984. Environmental Monitoring Program for Exploratory
Well Numbers 1 and 2, Lease OCS-G 4809, South Marsh Island Area Block 161. Prepared
for Mark Producing, Inc. 127 pp.
Continental Shelf Associates, Inc. 1982. Environmental Monitoring Program for Platform "A",
Lease OCS-G 3061 Block A-85, Mustang Island Area, East Addition, Near Baker Bank.
Prepared for Conoco Inc. 171 pp + app.
Daan, R., K. Booij, M. Mulder and E.M. van Weerlee. 1997. Environmental Effects of a
Discharge of Drill Cuttings Contaminated with Ester-based Drilling Muds in the North
Sea. Environ. Toxicol. Chem. 15(10): 1709-1772.
Daan, R., K. Booij, M. Mulder, and E. Van Weerlee. 1996. Environmental Effects of A
Discharge of Cuttings Contaminated with Ester-Based Drilling Muds in the North Sea,
Environmental Toxicology and Chemistry, Vol. 15, No. 10, pp. 1709-1722. April 9, 1996.
Dames & Moore. 1978. Drilling Fluid Dispersion and Biological Effects Study for the Lower
Cook Inlet C.O.S.T. Well. Prepared for Atlantic Richfield Company. April 1978.
-------
10-4
Davies, J.M., D.R. Bedborough, R.A.A. Blackman, J.M. Addy, J.F. Appelbee, W.C. Grogan,
J.G. Parker and A. Whitehead. 1989. The Environmental Effect of Oil-based Mud
Drilling in the North Sea. In: Drilling Wastes, F.R. Engelhardt, J.P. Ray and A.H. Gillam
(eds.). Elsevier Applied Science, New York. pp. 59-89.
Delvigne, G.A.L. 1996. Laboratory investigations on the fate and physiochemical properties of
drill cuttings after discharge into the sea. In: The Physical and Biological Effects of
Processed Oily Drill Cuttings. E & P Forum Report No. 2.61/202. April 1996. pp. 16-24.
Duke, T.W. and P.R. Parrish. 1984. Results of Drilling Fluids Program Sponsored by the Gulf
Breeze Research Laboratory 1976-1984, and Their Application to Hazard Assessment.
U.S. EPA Environmental Research Laboratory, Gulf Breeze, Florida. EPA-600/4-84-0055.
EG&G Environmental Consultants. 1982. A Study of Environmental Effects of Exploratory
Drilling on the Mid-Altantic Outer Continental Shelf-Final Report of the Block 684
Monitoring Program. Prepared for Offshore Operators Committee. October 1982.
Environment & Resource Technology. 1994a. Bioaccumulation Potential of ISO-TEQ Base
Fluid. ERT 94/209. Prepared for Baker Hughes INTEQ.
Environment & Resource Technology. 1994b. Bioconcentration Assessment Report,
Assessment of the bioconcentration factor (BCF) of ISO-TEQ base fluid in the blue mussel
Mytilus edulis. ERT 94/061. Prepared for Baker Hughes INTEQ.
Faerevik, I. 1997. Telefax to J. Daly, USEPA. Case: Environmental impacts of synthetic
drilling muds. 4 pp.
Faerevik, I. Undated. Discharges and regulations of synthetic drilling fluids on the Norwegian
Continental Shelf and summary of results from ecotoxicological testing and field surveys.
Norwegian Pollution Control Authority.
Friedheim, I.E. and R.M. Pantermuehl. 1993. Superior Performance with Minimal
Environmental Impact: A Novel Nonaqueous Drilling Fluid. SPE/IADC 25753.
Presented at the SPE/IADC Drilling Conference, Amsterdam, February 23-25, 1993. 14
pp.
Friedheim, I.E., et al. 1991. An Environmentally Superior Replacement for Mineral-Oil Drilling
Fluids. SPE 23062. Presented at the Offshore Europe Conference, Aberdeen, September 3-
6, 1991.
Fusaro, C. 1998. Telecommunication with Dr. C. Fusaro, Joint Oil and Fisheries Liaison by R.
Montgomery, The Pechan-Avanti Group. November 20, 1998.
Gillam, A.H., S.R.T. Severn and F.R. Engelhardt. 1989. Review of Biodegradability Test
Protocols for Drilling Fluid Base Oils. In: Drilling Wastes, F.R. Engelhardt, J.P. Ray and
A.H. Gillam (eds.). Elsevier Applied Science, New York. pp.685-698.
-------
10-5
Gj0s, N., F. Oreld, T. 0fsti, J. Smith, and S. May. 1991. Ula Well Site 7/12-9. Environmental
Survey 1991. SI Report No 910216-3, December 16. Cited in Vik, E.A., S. Dempsey, and
B.S. Nesgard. 1996. OLF Project Acceptance Criteria for Drilling Fluids, Evaluation of
Available Test Results from Environmental Studies of Synthetic Based Drill Muds.
Aquateam-Norwegian Water Technology Centre A/S Report No. 96-010.
Gj0s, N., F. Oreld, T. 0fsti, J. Smith, and S. May. 1992. Gyda Well Site 2/1-9. Environmental
Survey 1991. SI Report No 910216-5, August 10. Cited in Vik, E.A., S. Dempsey, and
B.S. Nesgard. 1996. OLF Project Acceptance Criteria for Drilling Fluids, Evaluation of
Available Test Results from Environmental Studies of Synthetic Based Drill Muds.
Aquateam-Norwegian Water Technology Centre A/S Report No. 96-010.
Gj0s, N., F. Oreld, T. Ofsti, J. Smith, and G. Hobbs. 1993. Gyda Well Site 2/1-9 Environmental
Survey. SINTEF Report STF 27 SF 93039, May 1993 (in Norwegian). Cited in Vik, E.A.,
S. Dempsey, and B.S. Nesgard. 1996. OLF Project Acceptance Criteria for Drilling
Fluids, Evaluation of Available Test Results from Environmental Studies of Synthetic
Based Drill Muds. Aquateam-Norwegian Water Technology Centre A/S Report No. 96-
010.
Gj0s, N. 1995. Environmental Monitoring Surveys at Sleipner A and Loke 1994. SINTEF
Report STF 27 F94057, February 15 (in Norwegian). Cited in Vik, E.A., S. Dempsey, and
B.S. Nesgard. 1996. OLF Project Acceptance Criteria for Drilling Fluids, Evaluation of
Available Test Results from Environmental Studies of Synthetic Based Drill Muds.
Aquateam-Norwegian Water Technology Centre A/S Report No. 96-010.
Gj0s, N., T. Jensen, and S.A. N01and. 1995a. Environmental Monitoring Survey Tordis 1994.
SINTEF Report STF 27 F940654, January 25. Cited in Vik, E.A., S. Dempsey, and B.S.
Nesgard. 1996. OLF Project Acceptance Criteria for Drilling Fluids, Evaluation of
Available Test Results from Environmental Studies of Synthetic Based Drill Muds.
Aquateam-Norwegian Water Technology Centre A/S Report No. 96-010.
Growcock, F.B., S.L. Andrews and T.P. Frederick. 1994. Physicochemical Properties of
Synthetic Drilling Fluids. IADC/SPE 27450, pp. 181-190. Presented at the IADC/SPE
Drilling Conference, Dallas, Texas, February 15-18, 1994.
Hood., C.A. 1997. Letter to J. Daly, USEPA with unpublished sediment toxicity data from
Baker Hughes, INTEQ. July 9, 1997.
Houghton, J.P., R.P. Britch, R.C. Miller, A.K. Runchal, and C.P. Falls. 1980. Drilling Fluid
Dispersion Studies at the Lower Cook Inlet, Alaska, COST Well. In: Symposium,
Research on Environmental Fate and Effects of Drilling Fluids and Cuttings, Lake Buena
Vista, Florida, January 21-24,1980. API, Washington, DC.
Houghton, J.P., K.R. Critchlow, D.C. Lees, and R.D. Czlopinski. 1981. Fate and Effects of
Drilling Fluids and Cuttings Discharges in Lower Cook Inlet, Alaska, and on Georges
Bank - Final Report. NOAA/BLM, Washington, DC.
-------
10-6
Jones, F.V., J.H. Rushing and M.A. Churan. 1991. The Chronic Toxicity of Mineral Oil-Wet
and Synthetic Liquid-Wet Cuttings on and Estuarine Fish, Fundulus grandis. SPE 23497.
pp. 721-730. Presented at the First International Conference on Health, Safety and
Environment, The Hague, The Netherlands, November 10-14, 1991.
Kenny, P., M. Norman, A.M. Friestad and B. Risvik. 1996. The Development and Field Testing
of a Less Hazardous and Technically Superior Oil Based Drilling Fluid. SPE 35952, pp.
527-535.
Larsen, M.M., AJ. Pedersen, and R. Jaques. 1995. Well Site 2/7-29 Environmental Survey
1994. DNV Report No. 95-3150, February 15. Cited in Vik, E.A., S. Dempsey, and B.S.
Nesgard. 1996. OLF Project Acceptance Criteria for Drilling Fluids, Evaluation of
Available Test Results from Environmental Studies of Synthetic Based Drill Muds.
Aquateam-Norwegian Water Technology Centre A/S Report No. 96-010.
Leaver, M.J., DJ. Murison, J.M. Davies and D. Rafaelli. 1987. Experimental studies of the
effects of drilling discharges. Phil. Trans. R. Soc. Lond. B 316, 625-640.
Lees, D.C. and J.P. Houghton. 1980. Effects of Drilling Fluids on Benthic Communities at the
Lower Cook Inlet C.O.S.T. Well. In: Symposium, Research on Environmental Fate and
Effects of Drilling Fluids and Cuttings, Lake Buena Vista, Florida, January 21-24, 1980.
API, Washington, DC.
Leuterman, A.J.J. 1991. Environmental Considerations in M-I Product Development
Novasol/Novadril. M-I Drilling Fluids Co., January 15, 1991.
LGL Ecological Research Associates, Inc. 1998. Opportunistic Sampling at a Synthetic Drilling
Fluid Discharge Site on the Continental Slope of the Northern Gulf of Mexico: The
Pompano Development, 10-11 July 1997 and 13-14 March 1998. Prepared for BP
Expl orati on Inc. 12pp.
Limia, J.M. 1997. Environmental Impact of Synthetic Muds: Testing for the Right Thing?
Presented at the Oil & Gas Exploration and Production Safety & Environment Conference.
March 1997, Perth, Australia. 12 pp.
Limia, J.M. 1996. Seabed Surveys: the Best Means to Assess the Environmental Impact of
Drilling Fluid Discharges? SPE 36048, pp.803-813.
Mariani, G., L. Sick and C. Johnson. 1980. An Environmental Monitoring Study to Assess the
Impact of Drilling Discharges in the Mid-Atlantic. III. Chemical and Physical Alterations
in the Benthic Environment. In: Symposium on Research on Environmental Fate and
Effects of Drilling Fluids and Cuttings. Lake Buena Vista, Florida, January 21-24, 1980.
API, Washington, DC.
McKee, K. Dowrick and S.J. Astleford. 1995. A New Development Towards Improved
Synthetic Based Mud Performance. SPE/IADC 29405, pp. 613-621.
-------
10-7
Meek, R.P. and J.P. Ray. 1980. Induced Sedimentation, Accumulation and Transport Resulting
from Exploratory Drilling Discharges of Drilling Fluids and Cuttings on the Southern
California Outer Continental Shelf. In: Symposium, Research on Environmental Fate and
Effects of Drilling Fluids and Cuttings, Lake Buena Vista, Florida, January 21-24,1980.
API, Washington, DC.
Menzie, C., Maurer, D., and Leathern, W. 1980. An Environmental Monitoring Study to Assess
the Impact of Drilling Discharges in the Mid-Atlantic. IV. The Effects of Drilling
Discharges on the Benthic Community. In: Symposium on Research on Environmental
Fate and Effects of Drilling Fluids and Cuttings. Lake Buena Vista, Florida, January 21-24,
1980. API, Washington, DC.
Minerals Management Service (MMS). 1991. Southern California bight Physical
Oceanography. Proceedings of a Workshop. USDOI, MMS, Pacific OCS Region. OCS
Study MMS 91-0033. 157 pp.
MMS. 1991. Draft Environmental Impact Statement Gulf of Mexico Sales 139 and 141: Central
and Western Planning Areas. USDOI, MMS, Gulf of Mexico OCS Region. OCS EIS/EA
MMS 91-0018.
MMS. 1989. Gulf of Mexico Physical Oceanography Program Final Report: Year 5; Volume II:
Technical Report. USDOI, MMS, Gulf of Mexico OCS Region. OCS Study MMS 89-
0068. 333pp.
MMS. 1988. Offshore Texas and Louisiana Marine Ecosystems Data Synthesis Volume 2:
Synthesis Report. USDOI, MMS, Gulf of Mexico OCS Region. OCS Study MMS 88-
0067.
MMS. 1985. Union Oil Project/Exxon Project Shamrock and Central Santa Maria Basin Area
Study EIS/EIR. Prepared by Arthur D. Little, Inc. for MMS, Co. of Santa Barbara, CA
State Lands Commission, CA Coastal Commission, and CA Office of Offshore
Development. OCS Study MMS #85-0020.
Montgomery, R. 1998. Memorandum to J. Daly, EPA, Regarding Draft API Sediment Toxicity
Protocol for Use With Synthetic-Based Drilling Fluids. December 11, 1998. Plus
attachments.
Munro, P.O., B. Croce, C.F. Moffat, N.A. Brown, A.D. Mclntosh, S.J. Hird and R.M. Staff.
1998. Solid-phase Test for Comparison of Degradation Rates of Synthetic Mud Base
Fluids Used in the Offshore Drilling Industry. Environ. Tox. and Chem. 17(10)1951-1959.
Munro, P.O., C.F. Moffet and R.M. Stagg. 1997a. Biodegradation of Base Fluids Used in
Synthetic Drilling Muds in a Solid-phase Test System. SPE 37861, pp. 1-9.
-------
10-8
Munro, P.O., C.F. Moffat, L. Couper, N.A. Brown, B. Croce and R.M. Stagg. 1997b.
Degradation of Synthetic Mud Base Fluids in a Solid-Phase Test System. The Scottish
Office of Agriculture and Fisheries Department. Fisheries Research Services Report No.
1/97, January 1997.
National Marine Fisheries Service (NMFS). 1998. Marine Recreational Fisheries Statistics
Survey. Online database at http://www.st.nmfs.gov/webrecr.
NMFS. 1997. Fisheries of the United States, 1996. Current Fishery Statistics No. 9600. US
Department of Commerce, National Oceanic and Atmospheric Administration.
Neff, J. M. M. Bothner, N. Maciolek, and J. Grassle. 1989. Impacts of Exploratory Drilling For
Oil and Gas on the Benthic Environment of Georges Bank. Marine Environmental
Research 27 (1989).
Northern Technical Services. 1981. Beaufort Sea Drilling Effluent Disposal Study. Prepared for
the Reindeer Island Stratigraphic Test Well Participants. Under the direction of Sohio
Alaska Petroleum Company. 329 pp.
Ooi, B-H. 1994. Marine Environmental Monitoring Program. SPE 27166 Society of Petroleum
Engineers, Inc. January 1994.
Rabke S. et al. 1998a. Interlaboratory Comparison of a 96-hour Mysidopsis bahia Bioassay
Using a Water Insoluble Synthetic-Based Drilling Fluid. Presented at 19th Annual Meeting
of Society of Environmental Toxicology and Chemistry Charlotte NC 1998.
Rabke S. and J. Candler. 1998b. Development of Acute Benthic Toxicity Testing for Monitoring
Synthetic-Based Muds Discharged Offshore. Presented at IBC Conference on Minimizing
the Environmental Effects of Offshore Drilling, Houston Texas, February 9, 1998.
Ray, J.P. and R.P. Meek. 1980. Water Column Characterization of Drilling Fluids Dispersion
from an Offshore Exploratory Well on Tanner Bank. In: Symposium, Research on
Environmental Fate and Effects of Drilling Fluids and Cuttings, Lake Buena Vista, Florida,
January 21-24,1980. API, Washington, DC.
Ray, J.P. and E.A. Shinn. 1975. Environmental Effects of Drilling Muds and Cuttings. In:
Conference Proceedings on Environmental Aspects of Chemical Use in Well-Drilling
Operations, Houston, Texas. May 21-23, 1975.
RCG/Hagler, Bailly, Inc. 1993. The Economic Benefits of Effluent Limitation Guidelines for
Offshore Oil and Gas Facilities. Prepared for U.S. EPA, Office of Science and
Technology. January 1993.
Ricchiazzi, A. and F. Gamble. 1996. Santa Barbara Channel Navigation Chart. Channel
Crossing Press.
-------
10-9
Rushing, J.H., M.A. Churan, and F.V. Jones. 1991. Bioaccumulation from Mineral Oil-Wet and
Synthetic Liquid-Wet Cuttings in an Estuarine Fish, Fundulus grandis. SPE 23497.
Presented at the First International Conference on Health, Safety and Environment, The
Hague, The Netherlands, November 10-14, 1991.
SAIC. 1998. Daily Average Per Capita Fish Consumption Estimates Based on the Combined
USDA 1989, 1990, and 1991 Continuing Survey of Food Intakes by Individuals (CSFII),
Volume I: Uncooked Fish Consumption National Estimates. Prepared for USEPA Office
of Science and Technology. March 1998.
Schaanning, M.T. 1996. Environmental Fate of Synthetic Drilling Fluids from Offshore
Drilling Operations - An Experimental Study of an Olefin-, Ether-, and Ester-Based Mud
System on Cuttings Deposited in Benthic Chambers. NIVA Report 0-94066. 55 pp. +
app.
Schaanning, M.T. 1995a. Evaluation of Overall Marine Impact of the Novadril Mud System.
NIVA Report 0-95018.
Schaanning, M.T. 1995b. Biodegradation of Ultidril Base Fluid and Drilling Mud on Cuttings
Deposited in Benthic Chambers. NIVA Report 0-94241, 0-95100. 64 pp. + app.
Schaanning, M.T. 1994. Test on Degradation of AQUAMUL BII Mud on Cuttings Under
Simulated Seabed Conditions. NIVA Report 0-93206. 81pp.
Schanning, M.T., K. Hylland, R. Lichtenthaler and B. Rygg. 1996. Biodegradation of Anco
Green and Novaplus Drilling Muds on Cuttings Deposited in Benthic Chambers. NIVA
Report 0-95144/0-95145. 77 pp. + app.
Slater, M., M.H. Hille and A. Molversmyr. 1995. Commonly Used Biodegradation Techniques
for Drilling Fluid Chemicals, Are They Popular? SPE/IADC 29376, pp. 387-397.
Smith, J. and SJ. May. 1991. Ula Wellsite 7/12-9 Environmental Survey 1991. A report to
SINTEF SI from the Field Studies Council Research Centre. November 1991.
Steber, J., C.-P. Ilerold and J.M. Limia. 1995. Comparative Evaluation of Anaerobic
Biodegradability of Hydrocarbons and Fatty Derivatives Currently Used as Drilling Fluids.
Chemosphere, Vol. 31, No. 4, pp. 3105-3118.
Steinhauer, M. et al. 1990. California OCS Phase II Monitoring Program Year-Three Annual
Report. Chapter 13. Program Synthesis and Recommendations.
Still, I. and J. Candler. 1997. Benthic Toxicity Testing of Oil-Based and Synthetic-Based
Drilling Fluids. Eighth International Symposium on Toxicity Assessment. Perth, Western
Australia. 25-30 May 1997.
-------
10-10
Thoresen, K.M., A. A. Hinds. 1983. A Review of the Environmental Acceptability and the
Toxicity of Diesel Oil Substitutes in Drilling Fluid Systems. IADC/SPE 11401, pp. 343-350.
Tillery, J.B. and R.E. Thomas. 1980. Heavy Metals Contamination from Petroleum Production
Platforms in the Central Gulf of Mexico. In: Symposium on Research on Environmental
Gate and Effects of Drilling Fluids and Cuttings. Lake Buena Vista, Florida, January
1980. API, Washington, D.C.
U.S. Department of Interior (DOI). 1976. Baseline monitoring studies. Mississippi, Alabama,
Florida Outer Continental Shelf 1975 - 1976. Volume VI, Rig Monitoring. Assessment of
the Environmental Impact of Exploratory Oil Drilling. Prepared by the State University
System of Florida, Institute of Oceanography. Contract 08550-CT5-30, Bureau of Land
Management.
U.S. DOI. 1977. Baseline Monitoring Studies, Mississippi, Alabama, Florida, Outer Continental
Shelf, 1975-1976. Volume VI. Rig Monitoring. (Assessment of the Environmental
Impact of Exploratory Oil Drilling). Prepared by the State University System of Florida,
Institute of Oceanography. Contract 08550-CT5-30, Bureau of Land Management,
Washington, D.C.
U.S. EPA. 1999. Development Document for Proposed Effluent Limitations Guidelines and
Standards for Synthetic-Based Drilling Fluids and other Non-Aqueous Drilling Fluids in
the Oil and Gas Extraction Point Source Category. Office of Science and Technology.
EPA-821-B-98-021.
U.S. EPA. 1998a. Cadmium, Copper, Lead, Nickel, Silver and Zinc: Proposed Sediment
Guidelines for the Protection of Benthic Organisms Technical Basis and Implementation.
U.S. EPA, Office of Science and Technology and Office of Research and Development.
90 pp. + app.
U.S. EPA. 1998b. Integrated Risk Information System (IRIS). Online database at
Http://www.epa.gov/ngispgm3/iris.
U.S. EPA. 1997. Tabulation of Water Quality Criteria. Health and Ecological Criteria Division.
February 1997.
U.S. EPA. 1993. Development Document For Effluent Limitations Guidelines and New Source
Performance Standards for the Offshore Subcategory of the Oil and Gas Extraction Point
Source Category. EPA 821-R-93-003.
U.S. EPA. 1989. Briefing Report to the EPA Science Advisory Board on the Equilibrium
Partitioning Approach to Generating Sediment Quality Criteria. Office of Water
Regulations and Standards. EPA 440/5-89-002.
U.S. EPA Region 10. 1984. Revised Preliminary Ocean Discharge Criteria Evaluation Gulf of
Alaska - Cook Inlet OCS Lease Sale 88 and State Lease Sales in Cook Inlet. Prepared by
Jones & Stokes Associates, Inc. and Tetra Tech, Inc.
-------
10-11
Veil, J.A., CJ. Burke and D.O. Moses. 1996. Synthetic-Based Muds Can Improve Drilling
Efficiency Without Polluting. Oil and Gas Journal. Vol. 94, No. 10. pp. 48-54.
Vik, E.A., S. Dempsey, B. Nesgard. 1996a. Evaluation of Available Test Results from
Environmental Studies of Synthetic Based Drilling Muds. OLF Project, Acceptance
Criteria for Drilling Fluids. Aquateam Report No. 96-010.
Vik, E.A., B.S. Nesgard, J.D. Berg, S.M. Dempsey, D.R. Johnson, L. Gawel, and E. Dalland.
1996b. Factors Affecting Methods for Biodegradation Testing of Drilling Fluids for
Marine Discharge. SPE 35981, pp. 697-711
Zevallos, M.A., J. Candler, J.H. Wood and L.M. Reuter. 1996. Synthetic-Based Fluids Enhance
Environmental Drilling Performance in Deepwater Locations. SPE 35329, pp. 235-242.
Zingula, R.P. 1975. Effects of Drilling Operations on the Marine Environment. In: Conference
Proceedings on Environmental Aspects of Chemical Use in Well-Drilling Operations,
Houston, Texas, May 21-23, 1975.
-------
APPENDIX A
CALCULATION OF
GULF OF MEXICO SHRIMP CATCH
-------
A-l
Exhibit A-l. Calculation of Gulf of Mexico Shrimp Catch
Landings (Ibs)
Catch:Landings Ratio
Catch (Ibs)
Catch by Location (Ibs)
0-3 miles
Coastal
Offshore
3-80 miles
Offshore Area (mi2)
0-3 mile
3-80 mile
Catch/Area (lbs/mi2)
0-3 mile
3-80 mile
Weighted Average Catch
(lb/mi2)
Texas
75,078,833
0.85
63,817,008
36,758,597
24,517,984
12,240,613
27,058,411
1,107
28,413
11,057
1,331
Louisiana
88,229,189
1.23
108,657,202
62,586,549
47,252,844
15,333,704
46,070,654
1,314
33,726
11,669
1,752
11,443
Source/Comment
NMFS, 1997/Avg. of 1995-96
landings
Offshore Environmental Assessment,
Table 3-9 (Avanti, 1993)
Landings * Catch/Landings ratio
Offshore Environmental Assessment,
Table 3-9 (Avanti, 1993)/catch *
0.576 = 0-3 mile portion of catch
0-3 mile portion * 0.668 (TX) or
0.755 (LA) determines portion of 0-3
mile segment that is offshore (as
opposed to coastal)
Offshore Environmental Assessment,
Table 3-11 (Avanti, 1993)
Assumes all shallow wells drilled are
in the Territorial Seas (0-3 mi);
weighted by total catch/state
-------
APPENDIX B
REANALYSIS OF
WATER QUALITY CRITERIA ASSESSMENT
-------
B-l
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF
WATER
December 29, 1998
MEMORANDUM
TO: Administrative Record, Synthetic-Based Drilling Fluids Effluent Guideline
FROM: Kathy Zirbser
SUBJECT: Revised Federal Water Quality Criteria
Water quality analyses in the Environmental Assessment of the Proposed Effluent Limitations
Guidelines Standards for Synthetic-Based Drilling Fluids and Other Non-Aqueous Drilling
Fluids in the Oil and Gas Extraction Point Source Category (hereafter referred to as the
Environmental Assessment) are based on national water quality criteria as recommended by EPA
in February 1997. These water quality criteria are now superseded by the recently revised criteria
as published in the Federal Register on Thursday, December 10, 1998 (attached). There is
insufficient time to incorporate the revised criteria into the Environmental Assessment Document
prior to rule proposal. EPA has, however, conducted an analysis to determine how the analysis
would change incorporating the new 1998 criteria recommendations. This analysis is attached
hereto.
-------
B-2
Changes in criteria for four pollutants affect the analysis. The criteria changes are as follows (in
redline/strikeout format):
Pollutant
Arsenic
Copper
Mercury
Phenol
National Recommended Water Quality Criteria
Saltwater Acute
(Mg/1)
69
9r4 4.8
1.8
Saltwater Chronic
(Mg/0
36
9r4 3.1
0^25 0.94
Human Health for
Consumption of
Organisms Only (//g/1)
OH4
—
OH-5- 0.051
4,600,000
In the Environmental Assessment water quality assessment, modeled pollutant concentrations are
compared to the most stringent of the saltwater acute, saltwater chronic, and human health
(organism consumption) criteria. With the above changes to the national recommended water
quality criteria, these most stringent values change as follows:
Pollutant
Arsenic
Copper
Mercury
Phenol
Most Stringent Criterion
for Comparison to Modeled
Concentrations (//g/1)
A 1 /I "5 fL
VJ. 1H- JO
2^ 3.1
(\ AO £T A AC 1
\J .\J^ J U.UJ) 1
4,600,000
No criterion
For each of the above pollutants, the criterion for comparison with modeled pollutant
concentrations becomes less stringent. As a result, the number of modeled criteria exceedances
for pore water is reduced (for the water column analysis, no exceedances are projected, as was
the case using the 1997 criteria). The total number of projected exceedances for model wells
(under both current practice and the discharge option) is reduced from 19 (using 1997 criteria) to
10 (using 1998 criteria). The changes in exceedances are as follows:
-------
B-3
Factors by Which Pore Water Pollutant Concentrations at the Edge of the 100-meter
Mixing Zone Would Exceed Federal Water Quality Criteria Recommendations for each
Regulatory Option and Model Well(a)
Discharge
Region
Gulf of
Mexico
California
Cook
Inlet,
Alaska
Pollutant
Arsenic
Chromium
Mercury
Metals
Composite11-1
Arsenic
Metals
Composite11-1
Arsenic
Metals
Composite^'
Shallow Water
Development
Well
Current
Practice
4-3-
—
—
1.1
—
—
—
—
Discharge
Option
(c)
Exploratory
Well
Current
Practice
2-7
1.7
—
2.3
Discharge
Option
—
—
—
1.3
Not applicable
Not applicable
Not applicable
Not applicable
Deep Water
Development
Well
Current
Practice
4-9
1.3
—
1.7
4-2
4-4-
Discharge
Option
4-4-
—
—
—
—
—
Not applicable
Not applicable
Exploratory
Well
Current
Practice
4^
2.8
4-2
3.7
Discharge
Option
25
1.6
—
2.1
Not applicable
Not applicable
Not applicable
Not applicable
(a) There would be no exceedances for any pollutants with the zero discharge option.
(b) Metals composite includes cadmium, copper, lead, nickel, silver, and zinc.
(c) "—" indicates no exceedances are predicted.
-------
Thursday
December 10, 1998
Part IV
Environmental
Protection Agency
National Recommended Water Quality
Criteria; Notice; Republication
-------
68354
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
ENVIRONMENTAL PROTECTION
AGENCY
[FRL-OW-6186-6a]
National Recommended Water Quality
Criteria; Republication
Editorial Note: FR Doc. 98-30272 was
originally published as Part IV (63 FR 67548-
67558) in the issue of Monday, December 7,
1998. At the request of the agency, due to
incorrect footnote identifiers in the tables,
the corrected document is being republished
in its entirety.
AGENCY: Environmental Protection
Agency (EPA).
ACTION: Compilation of recommended
water quality criteria and notice of
process for new and revised criteria.
SUMMARY: EPA is publishing a
compilation of its national
recommended water quality criteria for
157 pollutants, developed pursuant to
section 304 (a) of the Clean Water Act
(CWA or the Act). These recommended
criteria provide guidance for States and
Tribes in adopting water quality
standards under section 303(c) of the
CWA. Such standards are used in
implementing a number of
environmental programs, including
setting discharge limits in National
Pollutant Discharge Elimination System
(NPDES) permits. These water quality
criteria are not regulations, and do not
impose legally binding requirements on
EPA, States, Tribes or the public.
This document also describes changes
in EPA's process for deriving new and
revised 304 (a) criteria. Comments
provided to the Agency about the
content of this Notice will be considered
in future publications of water quality
criteria and in carrying out the process
for deriving water quality criteria. With
this improved process the public will
have more opportunity to provide data
and views for consideration by EPA.
The public may send any comments or
observations regarding the compilation
format or the process for deriving new
or revised water quality criteria to the
Agency now, or anytime while the
process is being implemented.
ADDRESSES: A copy of the document,
"National Recommended Water Quality
Criteria" is available from the U.S. EPA,
National Center for Environmental
Publications and Information, 11029
Kenwood Road, Cincinnati, Ohio 45242,
phone (513) 489-8190. The publication
is also available electronically at: http:/
/www.epa.gov/ost. Send an original and
3 copies of written comments to W-98-
24 Comment Clerk, Water Docket, MC
4104, US EPA, 401 M Street, S.W.,
Washington, D.C. 20460. Comments
may also be submitted electronically to
OW-Docket@epamail.epa.gov.
Comments should be submitted as a
WP5.1, 6.1 or an ASCII file with no form
of encryption. The documents cited in
the compilation of recommended
criteria are available for inspection from
9 to 4 p.m., Monday through Friday,
excluding legal holidays, at the Water
Docket, EB57, East Tower Basement,
USEPA, 401 M St., S.W., Washington,
D.C. 20460. For access to these
materials, please call (202) 260-3027 to
schedule an appointment.
FOR FURTHER INFORMATION CONTACT:
Cindy A. Roberts, Health and Ecological
Criteria Division (4304), U.S. EPA, 401
M. Street, S.W., Washington, D.C.
20460; (202) 260-2787;
roberts.cindy@epamail.epa.gov.
SUPPLEMENTARY INFORMATION:
I. What Are Water Quality Criteria?
Section 304(a)(l) of the Clean Water
Act requires EPA to develop and
publish, and from time to time revise,
criteria for water quality accurately
reflecting the latest scientific
knowledge. Water quality criteria
developed under section 304(a) are
based solely on data and scientific
judgments on the relationship between
pollutant concentrations and
environmental and human health
effects. Section 304 (a) criteria do not
reflect consideration of economic
impacts or the technological feasibility
of meeting the chemical concentrations
in ambient water. Section 304 (a) criteria
provide guidance to States and Tribes in
adopting water quality standards that
ultimately provide a basis for
controlling discharges or releases of
pollutants. The criteria also provide
guidance to EPA when promulgating
federal regulations under section 303(c)
when such action is necessary.
II. What is in the Compilation
Published Today?
EPA is today publishing a
compilation of its national
recommended water quality criteria for
157 pollutants. This compilation is also
available in hard copy at the address
given above.
The compilation is presented as a
summary table containing EPA's water
quality criteria for 147 pollutants, and
for an additional 10 pollutants, criteria
solely for organoleptic effects. For each
set of criteria, EPA lists a Federal
Register citation, EPA document
number or Integrated Risk Information
System (IRIS) entry (www.epa.gov/
ngispgm3/iris/irisdat). Specific
information pertinent to the derivation
of individual criteria may be found in
cited references. If no criteria are listed
for a pollutant, EPA does not have any
national recommended water quality
criteria.
These water quality criteria are the
Agency's current recommended 304 (a)
criteria, reflecting the latest scientific
knowledge. They are generally
applicable to the waters of the United
States. EPA recommends that States and
Tribes use these water quality criteria as
guidance in adopting water quality
standards pursuant to section 303(c) of
the Act and the implementing of federal
regulations at 40 CFR part 131. Water
quality criteria derived to address site-
specific situations are not included;
EPA recommends that States and Tribes
follow EPA's technical guidance in the
"Water Quality Standards Handbook—
2nd Edition," EPA, August 1994, in
deriving such site-specific criteria. EPA
recognizes that in limited circumstances
there may be regulatory voids in the
absence of State or Tribal water quality
standards for specific pollutants.
However, States and Tribes should
utilize the existing State and Tribal
narrative criteria to address such
situations; States and Tribes may
consult EPA criteria documents and
cites in the summary table for additional
information.
The national recommended water
quality criteria include: previously
published criteria that are unchanged;
criteria that have been recalculated from
earlier criteria; and newly calculated
criteria, based on peer-reviewed
assessments, methodologies and data,
that have not been previously
published.
The information used to calculate the
water quality criteria is not included in
the summary table. Most information
has been previously published by the
Agency in a variety of sources, and the
summary table cites those sources.
When using these 304 (a) criteria as
guidance in adopting water quality
standards, EPA recommends States and
Tribes consult the citations referenced
in the summary table for additional
information regarding the derivation of
individual criteria.
The Agency intends to revise the
compilation of national recommended
water quality criteria from time to time
to keep States and Tribes informed as to
the most current recommended water
quality criteria.
III. How Are National Recommended
Water Quality Criteria Used?
Once new or revised 304 (a) criteria
are published by EPA, the Agency
expects States and Tribes to adopt
promptly new or revised numeric water
quality criteria into their standards
consistent with one of the three options
-------
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
68355
in40CFR 131.11. These options are: (1)
Adopt the recommended section 304 (a)
criteria; (2) adopt section 304 (a) criteria
modified to reflect site-specific
conditions; or, (3) adopt criteria derived
using other scientifically defensible
methods. In adopting criteria under
option (2) or (3), States and Tribes must
adopt water quality criteria sufficient to
protect the designated uses of their
waters. When establishing a numerical
value based on 304 (a) criteria, States
and Tribes may reflect site specific
conditions or use other scientifically
defensible methods. However, States
and Tribes should not selectively apply
data or selectively use endpoints,
species, risk levels, or exposure
parameters in deriving criteria; this
would not accurately characterize risk
and would not result in criteria
protective of designated uses.
EPA emphasizes that, in the course of
carrying out its responsibilities under
section 303(c), it reviews State and
Tribal water quality standards to assess
the need for new or revised water
quality criteria. EPA generally believes
that five years from the date of EPA's
publication of new or revised water
quality criteria is a reasonable time by
which States and Tribes should take
action to adopt new or revised water
quality criteria necessary to protect the
designated uses of their waters. This
period is intended to accommodate
those States and Tribes that have begun
a triennial review and wish to complete
the actions they have underway,
deferring initiating adoption of new or
revised section 304 (a) criteria until the
next triennial review.
IV. What is the Status of Existing
Criteria While They Are Under
Revision?
The question of the status of the
existing section 304 (a) criteria often
arises when EPA announces that it is
beginning a reassessment of existing
criteria. The general answer is that
water quality criteria published by EPA
remain the Agency's recommended
water quality criteria until EPA revises
or withdraws the criteria. For example,
while undertaking recent reassessments
of dioxin, PCBs, and other chemicals,
EPA has consistently upheld the use of
the current section 304 (a) criteria for
these chemicals and considers them to
be scientifically sound until new, peer
reviewed, scientific assessments
indicate changes are needed. Therefore,
the criteria in today's notice are and will
continue to be the Agency's national
recommended water quality criteria for
States and Tribes to use in adopting or
revising their water quality standards
until superseded by the publication of
revised criteria, or withdrawn by notice
in the Federal Register.
V. What is the Process for Developing
New or Revised Criteria?
Section 304(a)(l) of the CWA requires
the Agency to develop and publish, and
from time to time revise, criteria for
water quality accurately reflecting the
latest scientific knowledge. The Agency
has developed an improved process that
it intends to use when deriving new
criteria or conducting a major
reassessment of existing criteria. The
purpose of the improved process is to
provide expanded opportunities for
public input, and to make the process
more efficient.
When deriving new criteria, or when
initiating a major reassessment of
existing criteria, EPA will take the
following steps.
1. EPA will first undertake a
comprehensive review of available data
and information.
2. EPA will publish a notice in the
Federal Register and on the Internet
announcing its assessment or
reassessment of the pollutant. The
notice will describe the data available to
the Agency, and will solicit any
additional pertinent data or views that
may be useful in deriving new or
revised criteria. EPA is especially
interested in hearing from the public
regarding new data or information that
was unavailable to the Agency, and
scientific views as to the application of
the relevant Agency methodology for
deriving water quality criteria.
3. After public input is received and
evaluated, EPA will then utilize
information obtained from both the
Agency's literature review and the
public to develop draft recommended
water quality criteria.
4. EPA will initiate a peer review of
the draft criteria. Agency peer review
consists of a documented critical review
by qualified independent experts.
Information about EPA peer review
practices may be found in the Science
Policy Council's Peer Review Handbook
(EPA 100-B-98-001, www.epa.gov).
5. Concurrent with the peer review in
step four, EPA will publish a notice in
the Federal Register and on the Internet,
of the availability of the draft water
quality criteria and solicit views from
the public on issues of science
pertaining to the information used in
deriving the draft criteria. The Agency
believes it is important to provide the
public with the opportunity to provide
scientific views on the draft criteria
even though we are not required to
invite and respond to written
comments.
6. EPA will evaluate the results of the
peer review, and prepare a response
document for the record in accordance
with EPA's Peer Review Handbook. EPA
at the same time will consider views
provided by the public on issues of
science. Major scientific issues will be
addressed in the record whether from
the peer review or the public.
7. EPA will then revise the draft
criteria as necessary, and announce the
availability of the final water quality
criteria in the Federal Register and on
the Internet.
VI. What is the Process for Minor
Revisions to Criteria?
In addition to developing new
criteria, and conducting major
reassessments of existing criteria, EPA
also from time to time recalculates
criteria based on new information
pertaining to individual components of
the criteria. For example, in today's
notice, EPA has recalculated a number
of criteria based on new, peer-reviewed
data contained in EPA's IRIS. Because
such recalculations normally result in
only minor changes to the criteria, do
not ordinarily involve a change in the
underlying scientific methodologies,
and reflect peer-reviewed data, EPA will
typically publish such recalculated
criteria directly as the Agency's
recommended water quality criteria. If it
appears that a recalculation results in a
significant change EPA will follow the
process of peer review and public input
outlined above. Further, when EPA
recalculates national water quality
criteria in the course of proposing or
promulgating state-specific federal
water quality standards pursuant to
section 303(c), EPA will offer an
opportunity for national public input on
the recalculated criteria.
VII. How Does the Process Outlined
Above Improve Public Input and
Efficiency?
In the past, EPA developed draft
criteria documents and announced their
availability for public comment in the
Federal Register. This led to new data
and views coming to EPA's attention
after draft criteria had already been
developed. Responding to new data
would sometimes lead to extensive
revisions.
The steps outlined above improve the
criteria development process in the
following ways.
1. The new process is Internet-based
which is in line with EPA policy for
public access and dissemination of
information gathered by EPA. Use of the
Internet will allow the public to be more
engaged in the criteria development
process than previously and to more
-------
68356
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
knowledgeably follow criteria
development. For new criteria or major
revisions, EPA will announce its
intentions to derive the new or revised
criteria on the Internet and include a list
of the available literature. This will give
the public an opportunity to provide
additional data that might not otherwise
be identified by the Agency.
2. The public now has two
opportunities to contribute data and
views, before development and during
development, instead of a single
opportunity after development.
3. EPA has instituted broader and
more formal peer review procedures.
This independent scientific review is a
more rigorous disciplinary practice to
ensure technical improvements in
Agency decision making. Previously,
EPA used the public comment process
outlined above to obtain peer review.
The new process allows for both public
input and a formal peer review,
resulting in a more thorough and
complete evaluation of the criteria.
4. Announcing the availability of the
draft water quality criteria on the
Internet will give the public an
opportunity to provide input on issues
of science in a more timely manner.
VIII. Where Can I Find More
Information About Water Quality
Criteria and Water Quality Standards?
For more information about water
quality criteria and Water Quality
Standards refer to the following: Water
Quality Standards Handbook (EPA 823-
B94-005a); Advanced Notice of
Proposed Rule Making (ANPRM), (63 FR
36742); Water Quality Criteria and
Standards Plan—Priorities for the
Future (EPA 822-R-98-003); Guidelines
and Methodologies Used in the
Preparation of Health Effects
Assessment Chapters of the Consent
Decree Water Criteria Documents (45 FR
79347); Draft Water Quality Criteria
Methodology Revisions: Human Health
(63 FR 43755, EPA 822-Z-98-001); and
Guidelines for Deriving Numerical
National Water Quality Criteria for the
Protection of Aquatic Organisms and
Their Uses (EPA 822/R-85-100);
National Strategy for the Development
of Regional Nutrient Criteria (EPA 822-
R-98-002).
These publications may also be
accessed through EPA's National Center
for Environmental Publications and
Information (NCEPI) or on the Office of
Science and Technology's Home-page
(www.epa.gov/OST).
IX. What Are the National
Recommended Water Quality Criteria?
The following compilation and its
associated footnotes and notes presents
the national recommended water quality
criteria.
-------
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
68357
FR cite/source
Human health for consumption of:
Saltwater
Freshwater
c
o
.<2l5>
c i
CO *
D)
O
CO *— v
D)_l
CD E
ji
0
0
0
0
0
^
15>
15>
15>
15>
6
w
o
"c
CO
1
g
CL
S8sgj
eeseses
S* CD ^~ CD
CN
OCNOCNCN?SCNCNCNCNCNCNCNOCNOCNO
cecececece°°cecececececece°cecece-^
LLLLLLLLLL, dS
Q Q Q ^- Q Q
incooodool^
T-'^t CN -^ 1^ CN
8 i : i
0_ |0) :
o ffl
r^ .
ii.
: :oO
O .§
•^ O)
nOOO'69
3
0
O
oT
, j= E 3
§.y HE
p c = c o
|S £-|£
-CNCO
a
CN
in
a
1 SjEslsIs
CN ^ 00 *P T- CO ^ T-'TJ-
CN T- 1^ O 1^ CO f CN CO
: CD ::::::::
r^r^^cod^^rdcDd
a
a :::::::::
:::::::::
88
CNCN
cece
LLLL
CNCN
CO CD
O
of °,
li
rfl
ino
338388883388833383833
OOOOT-OOT-T-T-T-OOOOT-T-T-OOOOOOT-OOT-OOOO
OOCNOCNCNCNCNOOCNCNCNOOOCNOCNOO
CDCO^-CD^-^-^-^-COCD^r^-^-COCDCO^-CD^-COCD
cecececececececececececececececececececece
r^r^CNr^CNCNCNCNr^r^CNCNCNr^r^r^CNr^CNI^r^
inincDincocDcocDinincocDcoininincDincoinin
' n ' ffl O CD -CD ' OO • : • 3 3 CO :Q
u ~. u o o o : o u " o o o ' u of of o :o
CQ m CQ O O J=I • J=! m" in i— TI— T CQ U in r- 1 r- 1 CD ip, O
a>™a>^-a>-o :8^°°o° CN;-CNo8"-coV
O) CO CO T— CN ^" i-^ T— T— OOCN^— ^ ^"OOLO^"r^CNr^T—
isiiyis! ?.isii§ji^i»i5»
cidd^co^-^ ^rddcor^^dcNCN^oin^r^
>•
CN ::::::::: : : :::::::::::::::::::::
(M ::::::::: : : :::::::::::::::::::::
T- CN O O T- •* CN CN O) t
in co^rool^i^inocN
COI^T-T- T-T-
io i i i i-g 5
oi^cDCNc^oo^cor^^cocoocoT-cocDinoooincocDincNi^ou:
CD CD
LU _c:
: :pi::::f~(1, ciciip
0) ^ ..g:£c'2c-C!;^^2£g
_ COf^CDOCDOQOOOOOo
| |n||-g|fellloll
O < CN < , ^'CD'CDC _S^^°
lpll|||p:||p|l||lll||
CNiCNic^coc^c^c^c^c^c^c^co^i-^^i-^i-^i-^i-^i-^i-^i-^i-in
CD
^
Q
o
^
^ _L
s U
4co
in in
o
CL
O
X
o
ce
o
ce
Q.
ce
o
ce
O
O
ce
a
LU
a
O
o
LU
ce:
-------
68358
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
FR cite/source
Human health for consumption of:
Saltwater
Freshwater
c
o
.<5^)
c i
ro *
D)
O
ro *— v
ff
§1
2^5)
81
sis
03
6
w
o
"c
ro
1
g
CL
CD CD ^ CD CD CD ^ CD CD CD CD ^ CD ^ ^
T-T-OOT-T- T-OOT-T-T- T- 00 T- 00 00
CNCNOCNCN CNOCNCNCN CN O CN O C
0:0:0:0:0: 0:0:0:0:0: o: 0:0:0:0:
LL LL LL LL LL LL LL LL LL LL LL LL LL LL LI-
CD CD LO CD CD CDLOCDCDCD CD LO CD LO LO
: CO : : • o : : :
: O : no"'''
*r O : 3 Q U. 4 U U U
•• O ' CQ Q LO CQ CQ CQ CQ
4 0~". 0 000)0)0) 0)
111 o o o ,-ro -* •* •* -3
CN CD LO r-- ~ O O O O O
: 3 : : CQ O O O O
ca ^ R f\| CQ CQ CQ CQ
4 <--> pi CQ CQ^TJ-TJ-TJ- TJ
CQ o 4 o O O ^" ^" ^" ^
ooo ffl o ooooo o
CN^_- T-CN CDOOOO O
OCN CNT- O)OOOO O
O) • •
,0 • •
CO : : : : : : :
LO : : : : : : :
0) : : : : : : :
;OO O O O O O 00 00 00 00 00 00 O O O 00 00 00 O fe 00 00 O 00 O SS O O O O O J£
CD CD CD CD CD CD CD ^ ^ ^ ^ ^ ^ CD CD CD ^ ^ ^ CD 9; ^ ^ CD ^ CD 9; CD CD CD CD CD 9;
CMCM CMCMCMCMCMOOOOO O CM CM CM O O O CM O O O CM O CM O CM CM CM CM CM O
^ ^ ^ ^ ^ ^ ^ CD CD CD CD CD CD ^ ^ ^ CD CD CD ^ ^: CD CD ^ CD ^ ^: ^ ^ ^ ^ ^" f\j
0:0: a: a: a: a: a: a: a: a: a: a: a: a: a: a: a: a: a: a: ^- 0^.0^.0^.0^. oz ^ QZ QZ QZ QZ a:°
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 ,f, 1 1 1 1 1 1 1 1 1 1 ,f, 1 1 1 1 1 1 1 1 1 1 ,f,
CNCN CN CN CN CN CN r- r- r- r- r- r- CN CN CN r- r- r- CN F? r-r-CNr- CN F? CN CN CN CN CNF?
COCO CD CD CD CD CD LO LO LO LO LO LO CD CD CD LO LO LO CD — LO LO CD LO CD — CD CD CD CD CD —
: CQ
• O
4 8".
CQ "CQ
•* S05
T- T-LO
4 '
ca ca
T-O 4
COO ffl
o-* oo
OT- T-
: : ::::::••:: : : : o 3- : : : 3 : : : : : u : : :
; ; : : CQ ' ' : : : CQ ^1 : ^ : : : : CQ : 4^
CQ CQ CQ" CQ" o ' '0 O°-O : °- 'oli O n °" °" °" n n ' O : 2 CQ" CQ" O ts|
oo 0)0)00or- o_o o0 o0oouo^-o>o Onjnj0. o:ocococo CN
CNCO O O |^.-CD CD O ^ O) (sfT- LO °. ^TO o ^O) O CD O) T- TJ- ^ ^_-O o Q o O O
LO-* OOT-CNCNOT-CNT-O) O CO T- O LO T- 00 O CN T- 00 T- T- T- O) O O O O O
• • O U ... ... • • CQ • - 4 • CQ • • • CQ 4 • U
CQ" CQ" H : : CQ o : 4 : LO N : o" : O) °- : : : co o" 4 CQ~
CQCQ ^-^-CQ :'4oOm m ' CQ r— 4 3 TJ- • CDmn ''T-O)ffl4 ,_
OO ^"^"O :t^^OOO4 OcQOO^cQ"^^"4 OLO4 cQ^Q^^"*^ ^
OO OOOQQ^"O (y^'O T— ^QOO^Q^OCQ" cQOOm Q Q O O T— T— O
COT- O O CN •* •* O CN CO CN O O CO T- O O CN T- O CO T- O O LO O) CN O O O O O
: : :::::::::: ::::::::: : : : : :::::: O
: : :::::::::: ::::::::: : : : : : : : : : : •*
- - - - - - o
- - - - - - o
: : :::::::::: ::::::::: : : : : : : : : O O
:: :::::::::: ::::::::: :::: ::O::(oa
: : :::::::::: ::::::::: : : : : :::::: O
: : :::::::::: ::::::::: : : : : :::::: TJ
- - - - - - o
- - - - - - o
: : :::::::::: ::::::::: : : : : : : O : : LO O
- - - - - - - - o • • O) -^
:: :::::::::: ::::::::: :::: ::cO::OCN
SCN CN O) 00 r- LO CO 00 CN CN O) T- TJ- O) 1^ CO 1^ 1^ CO O) CO T- T- r- T- CN CO CN CN CN O f- O f- T- CO •* T- LO T- CO CO O) f- CO 00 O T- CN CO f- O) 00 O)
LO CD CN CD CN r- LO CN O) •* 00 T- TJ- CN T- LO 00 00 CN T- O O CO CD ^ CD T- TJ- TJ- o •* CD ^ CO ^ 00 r- CN O) O) O LO LO ^ O T- O CN O ^ LO O) CD ^
ooo) o co o> T- oo LO co o> CN o o> •* co oo LO CD LO r- o r- LO r- •* o> CD T- r-- T- CN oo CD •* r- r- CD •* r- co LO CN o> r- CD co o o oo o oo oo oo oo r-
r-oo oocoooocNCDOLOT-r-T-T-oo i^ T- LO T- LO oo co LO T- CD T- TJ- ,- TJ- ,_ (o r- (si (o (o oo r- r- r- co oo T- oo CN T- CD LO o> o o> o> o> oo o> r-
ooo OOOOOCNO>LOLOOO>OT-T-CO T-OOOO)OT-LOO)^-OO)OOCOOOCNOT-CNOOOT- oor-CD o>r-O) O>CDCN OOOOCN CNOT- T-LOT- LO
T- CNT- CNT-CNT-T-CD T-T- OCN LOT- T- T-CDT-T-CN T- T- CD T-T-COCOCO CO
o) r—
CO
to • • to ^
O (D • c^ to Q) Q
C "^ a) QJ £ C £
C. Q) .." to to ^ C C C C C C
CL CL CN < «CQCQCQCQCQCt
CO-* LO CD r- 00 O) O T- CN CO -^
LOLO LO LO LO LO LO CD CD CD CD CD
in iiiii Mia lit i l
III 1 &&;
ill
•a
a>
o
O
o
Q.
O
X
o
QL
O
QL
Q.
C£
O
LL.
O
£
_l
o
QL
Q
LLJ
Q
O
O
LLJ
a:
-------
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
68359
CDCDtDtDtDtDtDtDtDtDtDtDOOtD
q q
O)-^
gg
oo
oo
oo
o o
ca ca
O) CO
gg
oo
oo
oo
O) OC
in in
CMCN
r^r-
LLJQ
QQ
99
^-^1
"•*'*
O
•^
o ca ca ca
8°°°
OCMCMCN
O
Tj-
o ca ca ca
o°.22
OT-T-T-
§ >• >•
d d d
5gg
ooo
ooo
d d
0 TJ-TJ-
T-COCO
r^oo
ooo
O >• >•
It O O
CO CO CO
ID ID ID
OOO
cicici
it d d
CM CM CM
OOO
LDOJCDO
<°cScMg
co->-
co
a:
111
^3^
O -
ooo
ooo
o d
CM CM
IT) IT)
O O
O
Heptachlor
Heptachlor Epoxide
Polvchlorinated Biohenvls
q q
5fe
oo
oo
oo
PH
o" o
ca ca
r^co
ofe
oo
oo
oo
CM
8
o
o
CM
O
CM
8
o
ci
CO
o
8001352
CBs
Toxaphene
ll
±±J o
p (/) J2 OJ
9J i_ -Q
.c 'o o ro
o &•*- =
Z Q.O, ra
3"s 5
-—C ra^rara
^^ 3 <" in .o^^
§i§f
Es^e-
ailc»5^
"
ria
inc
ife
luta
, th
rio
44
ion
rion
Ills
III!
2g-xS
^X
^j (fl .<» -I
CCfflW
^ (D
;c 3^
estos is the Maxi
lated human healt
alth
ed
tem
LI G
at L
)] w
rite
ich
tic li
poll
i.e.,
riter
58
.
riteri
riter
lue
mo
the
icals w
e aqu
for thi
al pcb
quality
(61 F
ar futur
uality
quality
to a v
eri
is bas
1 , Sept
the G
he Gre
CMC2
c
als hi
aquati
r this
pcbs, i
ality cr
(61 FR
future.
ality cr
ality cr
o a val
rion is
riterion
96-01
s and
ific to t
f2
in
a
o ^Q mfe — -^racw .(D°=!tooO(-)
" - ^ -- •- •' " m-Q P O
riteri
s rec
ter, (
the 1
ions t
CM
ig/l, r
A is
Bs a
6741
deri
s crit
s rec
s val
sub
s rec
s rec
the
org
c
his
atio
he
|i
PA
CB
26
he
his
his
This
ge
his
his
in t
he
rative
KTh
ent W
tween
sidera
LTh
12.83
M E
NP
Q
R
a
s
T
-------
68360
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR NON PRIORITY POLLUTANTS
FR cite/source
Human health for consumption of:
Saltwater
Freshwater
c
o
ro *
D)
0
O D)
+ ^~;
Q) C
2l5>
§1
6
w
O
"c
S
"13
"o
Q.
g
Q.
c
o
z
00
o
o
oo oA
.* ^ ce
-88-004
c
c
00
CM
5?
SQoooocnooooooooooooooooo
ooooo-<-oooooo^oooooooooo
^rcQCQCQCQ^CQCQCQCQCQCQ^CQCQCQCQCQCQCQCQCQCQ
^ LJ_
O(Y}Q_Q_OOOO(Y}
0
o
8
CM
>
'E
"a
J.
i —
00
o
o
12
l —
LL
^
c
o
Q
LLJ
LJJ
(/
LL
C
LJJ
Q.
LLJ
Q
X
LJJ
ce
E
LL
1 —
ce
o
ce
LL
x
LL
ce
LL.
SALTWATER CRITERIA ARE pH AND TEMPERATURE DEPENDENT0
NARRATIVE STATEMENT— SEE DOCUMENT
FOR PRIMARY RECREATION AND SHELLFISH USES— SEE DOCUMENT
in r-
0 T-
O) •*
O) t
CM CD
^" CD
r- r-
2 Aluminum pH 6.5-9.0
3 Ammonia
4 Aesthetic Qualities
5 Bacteria
X
8 I
w «
>, >, o Q 73
x x — — ^
c c ° O ro. 9 /i
Q. Q. Q. O CO
P P P . -X .
o m ti c ra
K- c S 2 ° "
- <» P E o -c 2
OOOOOOQLUOOXXJ=25
T-^T-T-T-T-T-T-T-T-CMCMCS
23 Methoxychlor ..
24 Mirex
25 Nitrates
26 Nitrosamines ..
-------
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
68361
O O
O O
03 m
o o
o o
00
00
oooooooo
00000:^00
mmmininginin
ooooo^oo
-"-co
o in 5°
OOOOOO:;CNO
ooooooy^Si
030303030303COQ,o
oooooo^c^g
.j.
°
GJ
S
e
o
o
Q.
LJ_
O
m
D)
^
c
Q
•*
0
o
>.'
"§<
CO i_
O 0)
Q.-1-1
g-S
x OJ
(Uul
(/) *tr
iEl
ro
£
i^
QJ
[E
'§_
<
o
CO
ra
"-;<
CO
O '— i
g§
Q- o
J_ ^
o ^~
**— 1 1 1
ro
±^-c
O °
0)"
^
LO
S
CO
in
ce
Ll_
8
in
8?
c
1 CO
^ ""^
III ^
1_ ro
^ CO
|.E
^ <"
"c^
•— fn
ELO
^ 00
ip'oJ
'^ £
E?
o *-
1 .c
^ ra
c o
3 ^_
CN Q.
dra
gg
r- .—
S 1^1
"ra o g
^^X
2 D)D)
to 0 ^^ ^ ^
^9 O 'co -n" Q- (-
in "*"' ra a) ra
^Sil^t
Q. >- _ .!5 £ o
iS|c5|
5 c ra -a .E
•S -§ ra c '0 o
^ co 2_ p §
co E w | E3
ra ^ o ra =j^
o
Q_
^
CO
L-
5
to
CO
2
ro
OJ
(0
IS
£
C
!c
CO
s
3
Q.
—
Q_
LLJ
^_T
00
00
-"-co
S'iS-
OOOOOOOOOOOOOOO;;CNO
oooooo;=oooooooo5'*Si
03030303030300303030303030303^(^0
(_>(_>(_> U
o o o o
<^
oo -^
-in CN
O T-
<: <
01
,_
O)
•* oo
882
o o o
o o o
CL,
LJJ
^
LJ U fO LJ LJ LJ
O O fg O O O
o
~Jif
LLJ
Q
n
a
LLJ
Z) LLJ
O CO
o
Qsl-
LLJ
a:
CO ^
1—
ce
a^
LLJ g
^
Q
CO ^
1 1 ^
LLJ
^
ce
a:
~7
co in CN
CD oo in
f in o
a^s
trosodibutylamine.h
trosodiethylamine.h
trosopyrrolidine.N .
1 and Grease
<
a:
LLJ
<
^
cc „
< CO
> 0
o
in
w
•»-
"*
w
U)
CO
CD
O
?
in
in
00
in
CD
[i
O)
in
CD
0
r^ CN in
^r oo co
f CO O)
CN CD 00
f°^8
r^
xygen, Dissolved ..
?rathion
sntachlorobenzene
H
0
I—
z
(_>(_>(_> U
O O O O
O
i i
P.CL,
LLJCNS
^
0
0
Q
LLJ
LLJ
CO
1
I—,
LLJ
LLJ
1-
?•
CO
LLJ
P
CK
CK
<
o
^~
CO
CN
| —
8
LLJ
W CL,"
1- CN
LLJ
LLJ
^
CO
LLJ
<
ce
/
O
CN
|—
(j
O
2
CO LI- CO
w
O)
C\l
Z
LLJ W
Z 2
C«)
LLJ ^ CN
OL^
QHJ
Q LLJ
LLJ CO
LLJ 1
(/
1
-7
LL
LL
<
1
LLJ
^
Z
CO Q
LLJ Z
> ^
-
CN co t in
CNCNCOCOCOCOCOCOCOCOCOCO-^--^--^-
^r ^r ^r
E° J7T £r-o
™ 1 ^ 1^
CO
ll&s
c ,
1
i
--
1
-o
111!
g-ra
.
s
i If
asji If
lSg^-SSSc
5 l!
Is Sis
!Bfi
I§? -
-
1 1
!!
M
Iflll
"
lli«
8,8 S
s; 84_, 8i5 ||
l Hi t|f:
a««§«g°i5gig«|a!
-------
68362
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
NATIONAL RECOMMENDED WATER QUALITY CRITERIA FOR ORGANOLEPTIC EFFECTS
Pollutant
1 Acenaphthene
2 Monochlorobenzene
3 3-Chlorophenol
4 4-Chlorophenol
5 2,3-Dichlorophenol
6 2 5-Dichlorophenol
7 2 6-Dichlorophenol
8 3,4-Dichlorophenol
9 2,4,5-Trichlorophenol
10 2 4 6-Trichlorophenol
11 234 6-Tetrachlorophenol
12 2-Methyl-4-Chlorophenol
13 3-Methyl-4-Chlorophenol
14 3-Methyl-6-Chlorophenol
15 2-Chlorophenol
16 Copper
17 2,4-Dichlorophenol
18 2 4-Dimethylphenol
19 Hexachlorocyclopentadiene
20 Nitrobenzene
21 Pentachlorophenol
22 Phenol
23 Zinc
CAS No.
208968
1 08907
1 06489
95954
88062
59507
95578
744058
1 20832
1 05679
77474
98953
87865
1 08952
7440666
Organoleptic
effect criteria
(l-ig/L)
20
20
0 1
0.1
0.04
05
02
0.3
1
2
1
1800
3000
20
0 1
1000
0.3
400
1
30
30
300
5000
FR cite/source
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
Gold Book
45 FR 79341
General Notes:
1. These criteria are based on prganoleptic (taste and odor) effects. Because of variations in chemical nomenclature systems, this listing of
pollutants does not duplicate the listing in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service (CAS) registry num-
bers, which provide a unique identification for each chemical.
National Recommended Water Quality Criteria
Additional Notes
1. Criteria Maximum Concentration and Criterion Continuous Concentration
The Criteria Maximum Concentration (CMC) is an estimate of the highest concentration of a material in surface water to which
an aquatic community can be exposed briefly without resulting in an unacceptable effect. The Criterion Continuous Concentration
(CCC) is an estimate of the highest concentration of a material in surface water to which an aquatic community can be exposed
indefinitely without resulting in an unacceptable effect. The CMC and CCC are just two of the six parts of a aquatic life criterion;
the other four parts are the acute averaging period, chronic averaging period, acute frequency of allowed exceedence, and chronic
frequency of allowed exceedence. Because 304 (a) aquatic life criteria are national guidance, they are intended to be protective of
the vast majority of the aquatic communities in the United States.
2. Criteria Recommendations for Priority Pollutants, Non Priority Pollutants and Organoleptic Effects
This compilation lists all priority toxic pollutants and some non priority toxic pollutants, and both human health effect and
Organoleptic effect criteria issued pursuant to CWA §304(a). Blank spaces indicate that EPA has no CWA §304(a) criteria recommenda-
tions. For a number of non-priority toxic pollutants not listed, CWA §304(a) "water + organism" human health criteria are not available,
but, EPA has published MCLs under the SDWA that may be used in establishing water quality standards to protect water supply
designated uses. Because of variations in chemical nomenclature systems, this listing of toxic pollutants does not duplicate the listing
in Appendix A of 40 CFR Part 423. Also listed are the Chemical Abstracts Service CAS registry numbers, which provide a unique
identification for each chemical.
3. Human Health Risk
The human health criteria for the priority and non priority pollutants are based on carcinogenicity of 10~6 risk. Alternate risk
levels may be obtained by moving the decimal point (e.g., for a risk level of 10-5, move the decimal point in the recommended
criterion one place to the right).
4. Water Quality Criteria Published Pursuant to Section 304(a) or Section 303(c) of the CWA
Many of the values in the compilation were published in the proposed California Toxics Rule (CTR, 62 FR 42160). Although
such values were published pursuant to Section 303 (c) of the CWA, they represent the Agency's most recent calculation of water
quality criteria and thus are published today as the Agency's 304 (a) criteria. Water quality criteria published in the proposed CTR
may be revised when EPA takes final action on the CTR.
5. Calculation of Dissolved Metals Criteria
The 304(a) criteria for metals, shown as dissolved metals, are calculated in one of two ways. For freshwater metals criteria that
are hardness-dependent, the dissolved metal criteria were calculated using a hardness of 100 mg/1 as CaCOs for illustrative purposes
only. Saltwater and freshwater metals' criteria that are not hardness-dependent are calculated by multiplying the total recoverable
criteria before rounding by the appropriate conversion factors. The final dissolved metals' criteria in the table are rounded to two
significant figures. Information regarding the calculation of hardness dependent conversion factors are included in the footnotes.
6. Correction of Chemical Abstract Services Number
The Chemical Abstract Services number (CAS) for Bis(2-Chloroisopropyl) Ether, has been corrected in the table. The correct CAS
number for this chemical is 39638-32-9. Previous publications listed 108-60-1 as the CAS number for this chemical.
-------
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices 68363
7. Maximum Contaminant Levels
The compilation includes footnotes for pollutants with Maximum Contaminant Levels (MCLs) more stringent than the recommended
water quality criteria in the compilation. MCLs for these pollutants are not included in the compilation, but can be found in the
appropriate drinking water regulations (40 CFR 141.11-16 and 141.60-63), or can be accessed through the Safe Drinking Water Hotline
(800-426-4791) or the Internet (http://www.epa.gov/ost/tools/dwstds-s.html).
8. Organoleptic Effects
The compilation contains 304 (a) criteria for pollutants with toxicity-based criteria as well as non-toxicity based criteria. The basis
for the non-toxicity based criteria are organoleptic effects (e.g., taste and odor) which would make water and edible aquatic life
unpalatable but not toxic to humans. The table includes criteria for organoleptic effects for 23 pollutants. Pollutants with organoleptic
effect criteria more stringent than the criteria based on toxicity (e.g., included in both the priority and non-priority pollutant tables)
are footnoted as such.
9. Category Criteria
In the 1980 criteria documents, certain recommended water quality criteria were published for categories of pollutants rather than
for individual pollutants within that category. Subsequently, in a series of separate actions, the Agency derived criteria for specific
pollutants within a category. Therefore, in this compilation EPA is replacing criteria representing categories with individual pollutant
criteria (e.g., 1,3-dichlorobenzene, 1,4-dichlorobenzene and 1,2-dichlorobenzene).
10. Specific Chemical Calculations
A. Selenium
(1) Human Health
In the 1980 Selenium document, a criterion for the protection of human health from consumption of water and organisms was
calculated based on a BCF of 6.0 L/kg and a maximum water-related contribution of 35 |ig Se/day. Subsequently, the EPA Office
of Health and Environmental Assessment issued an errata notice (February 23, 1982), revising the BCF for selenium to 4.8 L/kg.
In 1988, EPA issued an addendum (ECAO-CIN-668) revising the human health criteria for selenium. Later in the final National
Toxic Rule (NTR, 57 FR 60848), EPA withdrew previously published selenium human health criteria, pending Agency review of
new epidemiological data.
This compilation includes human health criteria for selenium, calculated using a BCF of 4.8 L/kg along with the current IRIS
RfD of 0.005 mg/kg/day. EPA included these recommended water quality criteria in the compilation because the data necessary for
calculating a criteria in accordance with EPA's 1980 human health methodology are available.
(2) Aquatic Life
This compilation contains aquatic life criteria for selenium that are the same as those published in the proposed CTR. In the
CTR, EPA proposed an acute criterion for selenium based on the criterion proposed for selenium in the Water Quality Guidance
for the Great Lakes System (61 FR 58444). The GLI and CTR proposals take into account data showing that selenium's two most
prevalent oxidation states, selenite and selenate, present differing potentials for aquatic toxicity, as well as new data indicating that
various forms of selenium are additive. The new approach produces a different selenium acute criterion concentration, or CMC, depending
upon the relative proportions of selenite, selenate, and other forms of selenium that are present.
EPA notes it is currently undertaking a reassessment of selenium, and expects the 304(a) criteria for selenium will be revised
based on the final reassessment (63 FR 26186). However, until such time as revised water quality criteria for selenium are published
by the Agency, the recommended water quality criteria in this compilation are EPA's current 304(a) criteria.
B. 1,2,4-Trichlorobenzene and Zinc
Human health criteria for 1,2,4-trichlorobenzene and zinc have not been previously published. Sufficient information is now available
for calculating water quality criteria for the protection of human health from the consumption of aquatic organisms and the consumption
of aquatic organisms and water for both these compounds. Therefore, EPA is publishing criteria for these pollutants in this compilation.
C. Chromium (III)
The recommended aquatic life water quality criteria for chromium (III) included in the compilation are based on the values presented
in the document titled: 1995 Updates: Water Quality Criteria Documents for the Protection of Aquatic Life in Ambient Water, however,
this document contains criteria based on the total recoverable fraction. The chromium (III) criteria in this compilation were calculated
by applying the conversion factors used in the Final Water Quality Guidance for the Great Lakes System (60 FR 15366) to the
1995 Update document values.
D. Ether, Bis (Chloromethyl), Pentachlorobenzene, Tetrachlorobenzene 1,2,4,5- Trichlorophenol
Human health criteria for these pollutants were last published in EPA's Quality Criteria for Water 1986 or "Gold Book". Some
of these criteria were calculated using Acceptable Daily Intake (ADIs) rather than RfDs. Updated ql*s and RfDs are now available
in IRIS for ether, bis (chloromethyl), pentachlorobenzene, tetrachlorobenzene 1,2,4,5-, and trichlorophenol, and were used to revise
the water quality criteria for these compounds. The recommended water quality criteria for ether, bis (chloromethyl) were revised
using an updated ql*, while criteria for pentachlorobenzene, and tetrachlorobenzene 1,2,4,5-, and trichlorophenol were derived using
an updated RfD value.
E. PCBs
In this compilation EPA is publishing aquatic life and human health criteria based on total PCBs rather than individual arochlors.
These criteria replace the previous criteria for the seven individual arochlors. Thus, there are criteria for a total of 102 of the 126
priority pollutants.
Dated: October 26, 1998.
J. Charles Fox,
Assistant Administrator, Office of Water.
-------
68364
Federal Register/Vol. 63, No. 237/Thursday, December 10, 1998/Notices
Appendix A—Conversion Factors for Dissolved Metals
Metal
Arsenic
Cadmium
Chromium III
Chromium VI
Coccer
Lead
Mercury
Nickel
Selenium
Silver
Zinc
Conversion fac-
tor freshwater
CMC
1.000
1 138672-[(ln
hardness)
(0.041838)]
0.316
0982
0960
1 .46203-[(ln
hardness)
(0.145712)]
085
0.998
085
0978
Conversion fac-
tor freshwater
CCC
1.000
1 101672-[(ln
hardness)
(0.041838)]
0.860
0962
0960
1 .46203-[(ln
hardness)
(0.145712)]
085
0.997
0986
Conversion fac-
tor saltwater
CMC
1.000
0994
0993
083
0.951
085
0.990
0.998
085
0946
Conversion fac-
tor saltwater
CCC
1.000
0994
0993
083
0.951
085
0.990
0.998
0946
Appendix B—Parameters for Calculating Freshwater Dissolved Metals Criteria That Are Hardness-Dependent
Chemical
Cadmium
Chromium III
Coccer
Lead
Nickel
Silver
Zinc
mA
1.128
0.8190
0.9422
1.273
0.8460
1.72
0.8473
bA
-3.6867
3.7256
- 1 .700
- 1 .460
2.255
-6.52
0.884
mc
0.7852
0.8190
0.8545
1.273
0.8460
0.8473
be
-2.715
0.6848
- 1 .702
-4.705
0.0584
0.884
Freshwater conversion factors (CF)
Acute
1.136672-[ln(hard-
ness)(0.041838)]
0316
0960
1 .46203-[ln (hard-
ness)(0.145712)]
0998
0.85
0.978
Chronic
1.101672-[ln (hard-
ness)(0.041838)]
0.860
0.960
1 .46203-[ln (hard-
ness)^. 14571 2)]
0.997
0.986
Appendix C—Calculation of Freshwater Ammonia Criterion
1. The one-hour average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three years
on the average, the CMC calculated using the following equation:
CMC = -
0.275
39.0
107.204-pH 1+1()pH-7.204
In situations where salmonids do not occur, the CMC may be calculated using the following equation:
0.411 58.4
CMC = -
.107.204-pH l+1()pH-7.20
2. The thirty-day average concentration of total ammonia nitrogen (in mg N/L) does not exceed, more than once every three
years on the average, the CCC calculated using the following equation:
0.0858
3.70
ccc =
Editorial Note: FR Doc. 98-30272 was originally published as Part IV (63 FR 67548-67558) in the issue of Monday, December
7, 1998. At the request of the agency, due to incorrect footnote identifiers in the tables, the corrected document is being republished
in its entirety.
[FR Doc. 98-30272 Filed 12-4-98; 8:45 am]
BILLING CODE 1505-01-D
-------
APPENDIX C
BRANDSMA, 1996
FIGURE 2
-------
Exhibit C-l. Figure 2, Brandsma, 1996
C-l
ioo,non
1,000-
~ 100-
.
i!
B MI
(MM
0.001
II. I I
n Solids
• Oil
* LC50
10
\
-.-11111 IOJMN
[Emc (minuies)
-------
APPENDIX D
CALCULATION OF
SEDIMENT PORE WATER POLLUTANT CONCENTRATIONS
FOR WATER QUALITY ANALYSES
-------
Exhibit D-l. Gulf of Mexico Deep Water Development Model Well
Pore Water Pollutant Concentration: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 778,050 Ibs
Whole Drilling Fluid Discharged per Well: 588 bbls
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutant Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Percent Pollutant Sediment . t Pore Water
Pollutants in Loadings per Well (Ibs) Pollutant/Synthetic Cone, at 100 m ar ' '°" ™ l"e" Cone, at 100 m
Drilling Waste Current Technology (11%) (%) (mg/kg) °r ea° a° °rS (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
78,414
778,050
856,464
112,075
0.5911
0.3224
0.7647
0.0000
1.6782
0.0863
0.0078
0.4470
0.5567
0.0549
18.8194
1.4663
2.7523
1.0586
0.0863
0.0549
0.0941
15.7220
41.21
711.2071
9,409.6800
1,203.2079
1.1448
6.8612
3.3273
31.2808
3.7654
4.7574
0.0004
6.1834
0.0054
11,381.42
979,963
5.27e-04
2.88e-04
6.82e-04
3.79e-08
7.70e-05
7.00e-06
3.99e-04
4.97e-04
4.90e-05
1.68e-02
1.31e-03
2.46e-03
9.45e-04
7.70e-05
4.90e-05
8.40e-05
1.40e-02
6.35e-01
8.40e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.24e-03
3.34e-07
5.52e-03
4.80e-06
l.OOe+04
5.29e-02
2.89e-02
6.84e-02
3.80e-06
7.72e-03
7.02e-04
4.00e-02
4.98e-02
4.91e-03
1.68e+00
1.31e-01
2.46e-01
9.47e-02
7.72e-03
4.91e-03
8.42e-03
1.41e+00
6.37e+01
8.42e+02
1.08e+02
1.02e-01
6.14e-01
2.98e-01
2.80e+00
3.37e-01
4.26e-01
3.35e-05
5.53e-01
4.82e-04
0.0795 4.59e-03
0.0407 1.28e-03
0.0113 8.45e-04
11.3380 4.71e-05
0.1100 9.28e-04
0.0180 1.38e-05
0.0050 2.72e-04
0.0340 6.26e-02
0.0063 9.03e-04
0.0200 5.38e-03
0.0430 4.45e-03
0.0041 6.30e-03
0.0021 1.93e+00
0.1300 1.53e+01
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeffor Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-l
-------
Exhibit D-2. Gulf of Mexico Deep Water Development Model Well
Pore Water Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination in SBF
Dry Cuttings Generated per Well: 778,050 Ibs
Whole Drilling Fluid Discharged Per Well: 337
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutants, Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Percent Pollutant Sediment . . . _x Pore Water
Pollutants in Loadings per Well (Ibs) Pollutant/Synthetic Cone, at 100 m ar ' '°n °6 'C'en Cone, at 100 m
or T each Tractors
Drilling Waste Discharge Option (7%) (%) (mg/kg) (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
44,886
778,050
822,936
64,190
0.3388
0.1848
0.4382
2.43e-05
0.9618
0.0494
0.0045
0.2559
0.3187
0.0314
10.7726
0.8394
1.5755
0.6060
0.0494
0.0314
0.0539
8.9996
23.59
407.1115
5,386.3200
688.7442
0.6553
3.9275
1.9070
17.9280
2.1581
2.7266
0.0002
3.5439
0.0031
6,515.03
893,666
5.28e-04
2.88e-04
6.83e-04
3.79e-08
7.69e-05
6.99e-06
3.99e-04
4.96e-04
4.89e-05
1.68e-02
1.31e-03
2.45e-03
9.44e-04
7.69e-05
4.89e-05
8.39e-05
1.40e-02
6.34e-01
8.39e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.25e-03
3.34e-07
5.52e-03
4.80e-06
5.74e+03
3.03e-02
1.65e-02
3.92e-02
2.18e-06
4.42e-03
4.02e-04
2.29e-02
2.85e-02
2.81e-03
9.64e-01
7.51e-02
1.41e-01
5.42e-02
4.42e-03
2.81e-03
4.82e-03
8.05e-01
3.64e+01
4.82e+02
6.16e+01
5.87e-02
3.52e-01
1.71e-01
1.60e+00
1.93e-01
2.44e-01
1.92e-05
3.17e-01
2.76e-04
0.0795 2.63e-03
0.0407 7.35e-04
0.0113 4.84e-04
11.34 2.70e-05
0.1100 5.31e-04
0.0180 7.90e-06
0.0050 1.56e-04
0.0340 3.58e-02
0.0063 5.17e-04
0.0200 3.08e-03
0.0430 2.55e-03
0.0041 3.61e-03
0.0021 l.lle+00
0.1300 8.75e+00
(b)
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeffor Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-2
-------
Exhibit D-3. Gulf of Mexico Deep Water Exploratory Model Well
Pore Water Pollutant Concentrations: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 1,729,910 Ibs
Whole Drilling Fluid Discharged per Well: 1308 bbls
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutant Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Percent Pollutant Sediment . t Pore Water
Pollutants in Loadings per Well (Ibs) Pollutant/Synthetic Cone, at 100 m ar ' '°" ™ l"e" Cone, at 100 m
Drilling Waste Current Technology (11%) (%) (mg/kg) °r CaC a° °rS (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
174,346
1,729,910
1,904,256
249,187
1.3148
0.7172
1.7010
0.0001
3.7331
0.1918
0.0174
0.9938
1.2379
0.1220
41.8430
3.2603
6.1195
2.3537
0.1918
0.1220
0.2092
34.9564
91.62
1,581.3008
20,921.5200
2,675.2173
2.5455
15.2553
7.4016
69.5839
8.3762
10.5829
0.0008
13.7550
0.0120
25,305.55
2,178,844
5.28e-04
2.88e-04
6.83e-04
3.79e-08
7.70e-05
7.00e-06
3.99e-04
4.97e-04
4.90e-05
1.68e-02
1.31e-03
2.46e-03
9.45e-04
7.70e-05
4.90e-05
8.40e-05
1.40e-02
6.35e-01
8.40e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.25e-03
3.34e-07
5.52e-03
4.80e-06
2.23e+04
1.18e-01
6.42e-02
1.52e-01
8.46e-06
1.72e-02
1.56e-03
8.90e-02
l.lle-01
1.09e-02
3.75e+00
2.92e-01
5.48e-01
2.11e-01
1.72e-02
1.09e-02
1.87e-02
3.13e+00
1.42e+02
1.87e+03
2.39e+02
2.28e-01
1.37e+00
6.63e-01
6.23e+00
7.50e-01
9.47e-01
7.46e-05
1.23e+00
1.07e-03
0.0796 1.02e-02
0.0407 2.85e-03
0.0113 1.88e-03
11.34 1.05e-04
0.1100 2.06e-03
0.0180 3.07e-05
0.0050 6.05e-04
0.0340 1.39e-01
0.0063 2.01e-03
0.0200 1.20e-02
0.0430 9.90e-03
0.0041 1.40e-02
0.0021 4.30e+00
0.1300 3.40e+01
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeffor Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-3
-------
Exhibit D-4. Gulf of Mexico Deep Water Exploratory Model Well
Pore Water Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination in SBF
Dry Cuttings Generated per Well: 1,729,910 Ibs
Whole Drilling Fluid Discharged Per Well: 749 bbls
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutants, Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Percent Pollutant Sediment . . . _x Pore Water
Pollutants in Loadings (Ibs) Pollutant/Synthetic Cone, at 100 m ar ' '°" "J; 'C'en Cone, at 100 m
Drilling Waste Discharge Option (7%) (%) (mg/kg) °r ea° a° °rS (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
99,799
1,729,910
1,829,709
142,719
0.7529
0.4107
0.9740
5.41e-05
2.1377
0.1098
0.0100
0.5689
0.7086
0.0699
23.9518
1.8662
3.5029
1.3473
0.1098
0.0699
0.1198
20.0097
52.44
905.1670
11,975.8800
1,531.3458
1.4571
8.7324
4.2384
39.8458
4.7965
6.0601
0.0005
7.8765
0.0069
14,485.41
1,986,968
5.28e-04
2.88e-04
6.82e-04
3.79e-08
7.69e-05
6.99e-06
3.99e-04
4.96e-04
4.89e-05
1.68e-02
1.31e-03
2.45e-03
9.44e-04
7.69e-05
4.89e-05
8.39e-05
1.40e-02
6.34e-01
8.39e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.25e-03
3.34e-07
5.52e-03
4.80e-06
1.28e+04
6.74e-02
3.68e-02
8.72e-02
4.84e-06
9.83e-03
8.93e-04
5.09e-02
6.34e-02
6.25e-03
2.14e+00
1.67e-01
3.14e-01
1.21e-01
9.83e-03
6.25e-03
1.07e-02
1.79e+00
8.10e+01
1.07e+03
1.37e+02
1.30e-01
7.82e-01
3.79e-01
3.57e+00
4.29e-01
5.42e-01
4.27e-05
7.05e-01
6.13e-04
0.0795 5.85e-03
0.0407 1.63e-03
0.0113 1.08e-03
11.34 6.00e-05
0.1100 1.18e-03
0.0180 1.76e-05
0.0050 3.46e-04
0.0340 7.96e-02
0.0063 1. 15e-03
0.0200 6.85e-03
0.0430 5.66e-03
0.0041 8.02e-03
0.0021 2.46e+00
0.1300 1.95e+01
(a)
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeffor Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-4
-------
Exhibit D-5. Gulf of Mexico Shallow Water Exploratory Model Well
Pore Water Pollutant Concentrations: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 1,077,440 Ibs
Whole Drilling Fluid Discharged per Well: 814 bbls
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutant Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Percent Pollutant Sediment . . . _x Pore Water
Pollutants in Loadings per Well (Ibs) Pollutant/Synthetic Cone, at 100 m ar ' '°" "J; 'C'en Cone, at 100 m
Drilling Waste Current Technology (11%) (%) (mg/kg) °r ea° a° °rS (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
108,588
1,077,440
1,186,028
155,202
0.8182
0.4463
1.0586
0.0001
2.3232
0.1194
0.0109
0.6190
0.7710
0.0760
26.0611
2.0306
3.8114
1.4659
0.1194
0.0760
0.1303
21.7719
57.06
984.8823
13,030.5600
1,666.2068
1.5854
9.5014
4.6062
43.3038
5.2127
6.5860
0.0005
8.5600
0.0074
15,761.01
1,357,050
5.27e-04
2.88e-04
6.82e-04
3.79e-08
7.70e-05
7.00e-06
3.99e-04
4.97e-04
4.90e-05
1.68e-02
1.31e-03
2.46e-03
9.45e-04
7.70e-05
4.90e-05
8.40e-05
1.40e-02
6.35e-01
8.40e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.24e-03
3.34e-07
5.52e-03
4.80e-06
1.39e+04
7.32e-02
3.99e-02
9.47e-02
5.26e-06
1.07e-02
9.72e-04
5.54e-02
6.90e-02
6.80e-03
2.33e+00
1.82e-01
3.41e-01
1.31e-01
1.07e-02
6.80e-03
1.17e-02
1.95e+00
8.82e+01
1.17e+03
1.49e+02
1.42e-01
8.50e-01
4.12e-01
3.88e+00
4.67e-01
5.89e-01
4.64e-05
7.66e-01
6.67e-04
0.0796
0.0407
0.0113
11.34
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
6.37e-03
1.78e-03
1.17e-03
6.52e-05
1.28e-03
1.91e-05
3.77e-04
8.66e-02
1.25e-03
7.45e-03
6.16e-03
8.73e-03
2.68e+00
2.12e+01
(a)
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeffor Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-5
-------
Exhibit D-6. Gulf of Mexico Shallow Water Exploratory Model Well
Pore Water Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination
Dry Cuttings Generated per Well: 1,077,440 Ibs
Whole Drilling Fluid Discharged Per Well: 466 bbls
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutants, Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of
Pollutants in
Drilling Waste
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
Pollutant Loadings per
Well (Ibs)
Discharge Option (7%)
62,158
1,077,440
1,139,598
88,890
0.4684
0.2555
0.6060
3.37e-05
1.3300
0.0684
0.0062
0.3543
0.4413
0.0435
14.9179
1.1624
2.1817
0.8391
0.0684
0.0435
0.0746
12.4627
32.66
563.7668
7,458.9600
953.7710
0.9075
5.4388
2.6369
24.7906
2.9842
3.7703
0.0003
4.9005
0.0043
9,021.93
1,237,544
Percent
Pollutant/Synthetic
(%)
5.27e-04
2.87e-04
6.82e-04
3.79e-08
7.69e-05
6.99e-06
3.99e-04
4.96e-04
4.89e-05
1.68e-02
1.31e-03
2.45e-03
9.44e-04
7.69e-05
4.89e-05
8.39e-05
1.40e-02
6.34e-01
8.39e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.24e-03
3.34e-07
5.51e-03
4.80e-06
Pollutant Sediment /-,«•• »i
Partition Coefficient
Cone, at 100 m
or J_i63.cn rjictors
(mg/kg)
7.96e+03
4.19e-02 0.0796
2.29e-02 0.0407
5.42e-02 0.0113
3.01e-06 11.34
6.12e-03 0.1100
5.56e-04 0.0180
3.17e-02
3.95e-02 0.0050
3.89e-03
1.34e+00 0.0340
1.04e-01 0.0063
1.95e-01 0.0200
7.51e-02 0.0430
6.12e-03
3.89e-03
6.68e-03
1.12e+00 0.0041
5.05e+01
6.68e+02 0.0021
8.54e+01 0.1300
8.12e-02
4.87e-01
2.36e-01
2.22e+00
2.67e-01
3.37e-01
2.66e-05
4.39e-01
3.82e-04
Pore Water
Cone, at 100 m
(mg/1) (a)
3.65e-03
1.02e-03
6.69e-04
3.73e-05
7.35e-04
1.09e-05
2.16e-04
4.96e-02
7.16e-04
4.27e-03
3.53e-03
5.00e-03
1.53e+00
1.21e+01
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeff or Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-6
-------
Exhibit D-7. Gulf of Mexico Shallow Water Development Model Well
Pore Water Pollutant Concentrations: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 514,150 Ibs
Whole Drilling Fluid Discharged per Well: 389 bbls
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutant Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Loadings Percent Pollutant Sediment . Pore Water
Partition Coefficient"
Pollutants in per Well (Ibs) Pollutant/Synthetic Cone, at 100 m Cone, at 100 m
Drilling Waste Current Technology (11%) (%) (mg/kg) °r ea° a° °rS (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
51,818
514,150
565,968
74,062
0.3910
0.2133
0.5059
0.0000
1.1102
0.0570
0.0052
0.2954
0.3679
0.0363
12.4363
0.9690
1.8188
0.6995
0.0570
0.0363
0.0622
10.3895
27.23
469.9841
6,218.1600
795.1109
0.7565
4.5341
2.2012
20.6943
2.4911
3.1473
0.0002
4.0907
0.0036
7,521.17
647,580
5.28e-04
2.88e-04
6.83e-04
3.79e-08
7.70e-05
7.00e-06
3.99e-04
4.97e-04
4.90e-05
1.68e-02
1.31e-03
2.46e-03
9.45e-04
7.70e-05
4.90e-05
8.40e-05
1.40e-02
6.35e-01
8.40e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.79e-02
3.36e-03
4.25e-03
3.35e-07
5.52e-03
4.81e-06
6.63e+03
3.50e-02
1.91e-02
4.53e-02
2.52e-06
5.10e-03
4.64e-04
2.64e-02
3.29e-02
3.25e-03
l.lle+00
8.67e-02
1.63e-01
6.26e-02
5.10e-03
3.25e-03
5.57e-03
9.30e-01
4.21e+01
5.57e+02
7.12e+01
6.77e-02
4.06e-01
1.97e-01
1.85e+00
2.23e-01
2.82e-01
2.22e-05
3.66e-01
3.19e-04
0.0796 3.04e-03
0.0407 8.49e-04
0.0113 5.59e-04
11.34 3.12e-05
0.1100 6.13e-04
0.0180 9.12e-06
0.0050 1.80e-04
0.0340 4.13e-02
0.0063 5.97e-04
0.0200 3.56e-03
0.0430 2.94e-03
0.0041 4.16e-03
0.0021 1.28e+00
0.1300 l.Ole+01
(a)
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeffor Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-7
-------
Exhibit D-8. Gulf of Mexico Shallow Water Development Model Well
Pore Water Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination in
Dry Cuttings Generated per Well: 514,150 Ibs
Whole Drilling Fluid Discharged Per Well: 223 bbls
SBF
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Total Priority Pollutants, Organics
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Total Priority Pollutant Metals
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Total Non-Conventional Pollutants
Total Loadings and Reductions (Ibs)
Avg. Cone, of Pollutant Loadings Percent Pollutant Sediment . t Pore Water
Pollutants in per Well (Ibs) Pollutant/Synthetic Cone, at 100 m ar ' '°" °* l"e" Cone, at 100 m
Drilling Waste Discharge Option (7%) (%) (mg/kg) °r CaC a° °rS (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
29,661
514,150
543,811
42,418
0.2242
0.1223
0.2900
1.61e-05
0.6364
0.0326
0.0030
0.1691
0.2106
0.0208
7.1186
0.5547
1.0411
0.4004
0.0326
0.0208
0.0356
5.9470
15.59
269.0223
3,559.3200
455.1273
0.4331
2.5953
1.2619
11.8633
1.4280
1.8043
0.0001
2.3451
0.0020
4,305.20
590,550
5.28e-04
2.88e-04
6.84e-04
3.80e-08
7.69e-05
6.99e-06
3.99e-04
4.96e-04
4.89e-05
1.68e-02
1.31e-03
2.45e-03
9.44e-04
7.69e-05
4.89e-05
8.39e-05
1.40e-02
6.34e-01
8.39e+00
1.07e+00
1.02e-03
6.12e-03
2.97e-03
2.80e-02
3.37e-03
4.25e-03
3.35e-07
5.53e-03
4.81e-06
3.80e+03
2.01e-02
1.09e-02
2.60e-02
1.44e-06
2.92e-03
2.65e-04
1.51e-02
1.88e-02
1.86e-03
6.37e-01
4.96e-02
9.32e-02
3.58e-02
2.92e-03
1.86e-03
3.19e-03
5.32e-01
2.41e+01
3.19e+02
4.07e+01
3.88e-02
2.32e-01
1.13e-01
1.06e+00
1.28e-01
1.61e-01
1.27e-05
2.10e-01
1.83e-04
0.0796
0.0407
0.0113
11.34
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
1.74e-03
4.87e-04
3.20e-04
1.79e-05
3.51e-04
5.22e-06
1.03e-04
2.37e-02
3.42e-04
2.04e-03
1.68e-03
2.38e-03
7.31e-01
5.78e+00
Pore water cone. = (Pollutant Sed. Cone. * Partition Coeff or Leach Factor) * 35.5 kg sediment / 32.5 liter pore water unit volume
D-8
-------
APPENDIX E
CALCULATION OF
FINFISH TISSUE POLLUTANT CONCENTRATIONS
-------
E-l
Exhibit E-l. Recreational Finfish Tissue Pollutant Concentrations - Gulf of Mexico
Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
(A)
Average
Concentration
(mg/1)
1.170
0.6382
1.5136
0.0001
0.1707
0.0155
0.8843
1.1015
0.1086
37.233
2.9011
5.4453
2.0944
0.1707
0.1086
0.1862
31.11
1,407
18,516
2,380
2.265
13.575
(B)
Leach
Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
(C)
Ambient
Bioavailable
Cone, in Plume
(mg/1)
l.Ole-04
5.49e-05
1.30e-04
8.60e-09
1.62e-06
2.40e-08
7.61e-05
4.74e-07
9.34e-06
1.09e-04
1.57e-06
9.37e-06
7.75e-06
1.47e-05
9.34e-06
1.60e-05
1.10e-05
1.21e-01
1.59e+00
2.05e-01
1.95e-04
1.17e-03
(D)
Average
Exposure
Concentration
(mg/1)
7.15e-07
3.90e-07
9.25e-07
6.11e-ll
1.15e-08
1.70e-10
5.40e-07
3.36e-09
6.63e-08
7.73e-07
1.12e-08
6.65e-08
5.50e-08
1.04e-07
6.63e-08
1.14e-07
7.79e-08
8.59e-04
1.13e-02
1.45e-03
1.38e-06
8.29e-06
(E)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(F)
Fish Tissue
Concentration
(mg/kg)
3.04e-04
1.17e-05
2.43e-03
8.55e-ll
7.34e-07
9.37e-07
5.40e-07
1.48e-07
1.26e-06
1.24e-05
4.02e-07
3.26e-06
2.59e-06
5.00e-07
3.32e-08
1.32e-05
3.66e-06
1.99e-01
(a) There are no BCFs for specific SBF compounds.
Table Calculations:
Average number of dilutions in area within mixing zone (100 m radius) = 11,624
SBF plume volume = time to reach 100 m * discharge rate * no. of dilutions =
(11.1 min. * 0.0175 mVmin) * 11,624 dilutions = 2,257.9
Mixing zone cylinder volume = 314,000 m3; based on 100 m radius and
10 m depth = time to reach 100 m (11 min) * fall velocity (0.015 m/sec)
SBF plume portion of cylinder volume =
0.72% = fractional area of mixing zone affected by plume (2,257.9/314,000)
C= A * B/dilutions (B is assumed to be 1 unless otherwise noted)
D= C * 0.0072 (SBF plume portion of cylinder)
F= D * E (exposure cone. * BCF)
-------
E-2
Exhibit E-2. Recreational Finfish Tissue Pollutant Concentrations - Gulf of Mexico
Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
(A)
Average
Concentration
(mg/1)
0.811
0.4424
1.0494
0.0001
0.1183
0.0108
0.6128
0.7634
0.0753
25.804
2.011
3.774
1.4515
0.1183
0.0753
0.129
21.56
975.2
12,902
1,650
1.570
9.408
(B)
Leach
Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
(C)
Ambient
Bioavailable
Cone, in Plume
(mg/1)
6.98e-05
3.81e-05
9.03e-05
8.60e-09
1.12e-06
1.67e-08
5.27e-05
3.28e-07
6.48e-06
7.55e-05
1.09e-06
6.49e-06
5.37e-06
1.02e-05
6.48e-06
l.lle-05
7.60e-06
8.39e-02
l.lle+00
1.42e-01
1.35e-04
8.09e-04
(D)
Average
Exposure
Concentration
(mg/1)
4.95e-07
2.70e-07
6.41e-07
6.116-11
7.95e-09
1.19e-10
3.74e-07
2.33e-09
4.60e-08
5.36e-07
7.74e-09
4.61e-08
3.81e-08
7.23e-08
4.60e-08
7.88e-08
5.40e-08
5.96e-04
7.88e-03
l.Ole-03
9.59e-07
5.75e-06
(E)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(F)
Fish Tissue
Concentration
(mg/kg)
2.11e-04
8.11e-06
1.69e-03
8.556-11
5.09e-07
6.53e-07
3.74e-07
1.03e-07
8.74e-07
8.57e-06
2.79e-07
2.26e-06
1.79e-06
3.47e-07
2.30e-08
9.14e-06
2.54e-06
1.386-01
(a) There are no BCFs for specific SBF compounds.
Table Calculations:
Average number of dilutions in area within mixing zone (100 m radius) = 11,624
SBF plume volume = time to reach 100 m * discharge rate * no. of dilutions =
(11.1 min. * 0.0175 nrVmin) * 11,624 dilutions = 2,257.9
Mixing zone cylinder volume = 314,000 m3; based on 100 m radius and
10 m depth = time to reach 100 m (11 min) * fall velocity (0.015 m/sec)
SBF plume portion of cylinder volume =
0.72% = fractional area of mixing zone affected by plume (2,257.9/314,000)
C= A * B/dilutions (B is assumed to be 1 unless otherwise noted)
D= C * 0.0072 (SBF plume portion of cylinder)
F= D * E (exposure cone. * BCF)
-------
E-3
Exhibit E-3. Recreational Finfish Tissue Pollutant Concentrations - Cook Inlet, Alaska
Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
(A)
Average
Concentration
(mg/1)
1.170
0.6382
1.5136
0.0001
0.1707
0.0155
0.8843
1.1015
0.1086
37.233
2.9011
5.4453
2.0944
0.1707
0.1086
0.1862
31.11
1,407
18,516
2,380
2.265
13.575
(B)
Leach
Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
(C)
Ambient
Bioavailable
Cone, in Plume
(mg/1)
4.04e-04
2.21e-04
5.23e-04
3.46e-08
6.49e-06
9.64e-08
3.06e-04
1.90e-06
3.75e-05
4.38e-04
6.32e-06
3.76e-05
3.11e-05
5.90e-05
3.75e-05
6.44e-05
4.41e-05
4.866-01
6.40e+00
8.23e-01
7.83e-04
4.69e-03
(D)
Average
Exposure
Concentration
(mg/1)
7.25e-07
3.96e-07
9.38e-07
6.206-11
1.16e-08
1.73e-10
5.48e-07
3.41e-09
6.73e-08
7.85e-07
1.13e-08
6.75e-08
5.58e-08
1.06e-07
6.73e-08
1.15e-07
7.90e-08
8.72e-04
1.15e-02
1.48e-03
1.40e-06
8.41e-06
(E)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(F)
Fish Tissue
Concentration
(mg/kg)
3.09e-04
1.19e-05
2.47e-03
8.686-11
7.45e-07
9.51e-07
5.48e-07
1.50e-07
1.28e-06
1.26e-05
4.08e-07
3.31e-06
2.62e-06
5.08e-07
3.37e-08
1.34e-05
3.72e-06
2.01e-01
(a) There are no BCFs for specific SBF compounds.
Table Calculations:
Average number of dilutions in area within mixing zone (100 m radius) = 2,893
SBF plume volume = time to reach 100 m * discharge rate * no. of dilutions =
(4.2 min. * 0.0175 nrVmin) * 2,893 dilutions = 211.1 m3
Mixing zone cylinder volume = 117,750 m3; based on 100 m radius and
3.75 m depth = time to reach 100 m (4.2 min) * fall velocity (0.015 m/sec)
SBF plume portion of cylinder volume =
0.18% = fractional area of mixing zone affected by plume (211.1/117,750)
C= A * B/dilutions (B is assumed to be 1 unless otherwise noted)
D= C * 0.0018 (SBF plume portion of cylinder)
F= D * E (exposure cone, x BCF)
-------
E-4
Exhibit E-4. Recreational Finfish Tissue Pollutant Concentrations - Cook Inlet, Alaska
Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
(A)
Average
Concentration
(mg/1)
0.811
0.4424
1.0494
0.0001
0.1183
0.0108
0.6128
0.7634
0.0753
25.804
2.011
3.774
1.4515
0.1183
0.0753
0.129
21.56
975.2
12,902
1,650
1.570
9.408
(B)
Leach
Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
(C)
Ambient
Bioavailable
Cone, in Plume
(mg/1)
2.80e-04
1.53e-04
3.63e-04
3.46e-08
4.50e-06
6.72e-08
2.12e-04
1.32e-06
2.60e-05
3.03e-04
4.38e-06
2.61e-05
2.16e-05
4.09e-05
2.60e-05
4.46e-05
3.05e-05
3.37e-01
4.46+00
5.70e-01
5.43e-04
3.25e-03
(D)
Average
Exposure
Concentration
(mg/1)
5.03e-07
2.74e-07
6.50e-07
6.20e-ll
8.07e-09
1.21e-10
3.80e-07
2.37e-09
4.67e-08
5.44e-07
7.85e-09
4.68e-08
3.87e-08
7.33e-08
4.67e-08
8.00e-08
5.48e-08
6.04e-04
8.00e-03
1.02e-03
9.73e-07
5.83e-06
(E)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(F)
Fish Tissue
Concentration
(mg/kg)
2.14e-04
8.23e-06
1.71e-03
8.68e-ll
5.16e-07
6.63e-07
3.80e-07
1.04e-07
8.87e-07
8.70e-06
2.83e-07
2.29e-06
1.82e-06
3.52e-07
2.33e-08
9.27e-06
2.57e-06
1.40e-01
(a) There are no BCFs for specific SBF compounds.
Table Calculations:
Average number of dilutions in area within mixing zone (100 m radius) = 2,893
SBF plume volume = time to reach 100 m * discharge rate * no. of dilutions =
(4.2 min. * 0.0175 nrVmin) * 2,893 dilutions = 211.1 m3
Mixing zone cylinder volume = 117,750 m3; based on 100 m radius and
3.75 m depth = time to reach 100 m (4.2 min) * fall velocity (0.015 m/sec)
SBF plume portion of cylinder volume =
0.18% = fractional area of mixing zone affected by plume (211.1/117,750)
C= A * B/dilutions (B is assumed to be 1 unless otherwise noted)
D= C * 0.0018 (SBF plume portion of cylinder)
F= D * E (exposure cone, x BCF)
-------
E-5
Exhibit E-5. Recreational Finfish Tissue Pollutant Concentrations - Offshore California
Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
(A)
Average
Concentration
(mg/1)
1.170
0.6382
1.5136
0.0001
0.1707
0.0155
0.8843
1.1015
0.1086
37.233
2.9011
5.4453
2.0944
0.1707
0.1086
0.1862
31.11
1,407
18,516
2,380
2.265
13.575
(B)
Leach
Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
(C)
Ambient
Bioavailable
Cone, in Plume
(mg/1)
3.40e-04
1.85e-04
4.40e-04
2.91e-08
5.46e-06
8.11e-08
2.57e-04
1.60e-06
3.16e-05
3.68e-04
5.31e-06
3.16e-05
2.62e-05
4.96e-05
3.16e-05
5.41e-05
3.71e-05
4.09e-01
5.38e+00
6.92e-01
6.58e-04
3.94e-03
(D)
Average
Exposure
Concentration
(mg/1)
6.90e-08
3.77e-08
8.93e-08
5.90e-12
l.lle-09
1.656-11
5.22e-08
3.25e-10
6.41e-09
7.47e-08
1.08e-09
6.43e-09
5.31e-09
l.Ole-08
6.41e-09
1.10e-08
7.53e-09
8.30e-05
1.09e-03
1.41e-04
1.34e-07
8.01e-07
(E)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(F)
Fish Tissue
Concentration
(mg/kg)
2.94e-05
1.13e-06
2.35e-04
8.26e-12
7.09e-08
9.06e-08
5.22e-08
1.43e-08
1.22e-07
1.20e-06
3.88e-08
3.15e-07
2.50e-07
4.84e-08
3.20e-09
1.27e-06
3.54e-07
1.92e-02
(a) There are no BCFs for specific SBF compounds.
Table Calculations:
Average number of dilutions in area within mixing zone (100 m radius) = 3,442
SBF plume volume = time to reach 100 m * discharge rate * no. of dilutions =
(5.5 min. * 0.0175 nrVmin) * 3,442 dilutions = 331 m3
Mixing zone cylinder volume = 157,000 m3; based on 100 m radius and
5 m depth = time to reach 100 m (5.5 min) * fall velocity (0.015 m/sec)
SBF plume portion of cylinder volume =
0.21% = fractional area of mixing zone affected by plume (331/157,000)
C= A * B/dilutions (B is assumed to be 1 unless otherwise noted)
D= C * 0.0021 (SBF plume portion of cylinder)
F= D * E (exposure cone, x BCF)
-------
E-6
Exhibit E-6. Recreational Finfish Tissue Pollutant Concentrations - Offshore California
Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
(A)
Average
Concentration
(mg/1)
0.811
0.4424
1.0494
0.0001
0.1183
0.0108
0.6128
0.7634
0.0753
25.804
2.0106
3.7738
1.4515
0.1183
0.0753
0.129
21.56
975
12,902
1,649
1.570
9.408
(B)
Leach
Factor
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
(C)
Ambient
Bioavailable
Cone, in Plume
(mg/1)
2.36e-04
1.29e-04
3.05e-04
2.91e-08
3.78e-06
5.65e-08
1.78e-04
l.lle-06
2.19e-05
2.55e-04
3.68e-06
2.19e-05
1.81e-05
3.44e-05
2.19e-05
3.75e-05
2.57e-05
2.83e-01
3.75e+00
4.79e-01
4.56e-04
2.73e-03
(D)
Average
Exposure
Concentration
(mg/1)
4.79e-08
2.61e-08
6.19e-08
5.90e-12
7.68e-10
1.15e-ll
3.62e-08
2.25e-10
4.43e-09
5.18e-08
7.47e-10
4.45e-09
3.68e-09
6.98e-09
4.44e-09
7.61e-09
5.22e-09
5.75e-05
7.61e-04
9.74e-05
9.26e-08
5.55e-07
(E)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(F)
Fish Tissue
Concentration
(mg/kg)
2.039e-05
7.831e-07
1.629e-04
8.261e-12
4.914e-08
6.309e-08
3.616e-08
9.910e-09
8.442e-08
8.283e-07
2.691e-08
2.182e-07
1.731e-07
3.351e-08
2.222e-09
8.830e-07
2.451e-07
1.329e-02
(a) There are no BCFs for specific SBF compounds.
Table Calculations:
Average number of dilutions in area within mixing zone (100 m radius) = 3,442
SBF plume volume = time to reach 100 m * discharge rate * no. of dilutions =
(5.5 min. * 0.0175 nrVmin) * 3,442 dilutions = 331 m3
Mixing zone cylinder volume = 157,000 m3; based on 100 m radius and
5 m depth = time to reach 100 m (5.5 min) * fall velocity (0.015 m/sec)
SBF plume portion of cylinder volume =
0.21% = fractional area of mixing zone affected by plume (331/157,000)
C= A * B/dilutions (B is assumed to be 1 unless otherwise noted)
D= C * 0.0021 (SBF plume portion of cylinder)
F= D * E (exposure cone, x BCF)
-------
APPENDIX F
CALCULATION OF
SEDIMENT PORE WATER POLLUTANT CONCENTRATIONS
FOR SHRIMP TISSUE
POLLUTANT CONCENTRATION CALCULATION
-------
Exhibit F-l. Gulf of Mexico Shallow Water Development Model Well
Pore Water Concentrations for Calculation of Shrimp Tissue Pollutant Concentrations: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 514,150 Ibs
Whole Drilling Fluid Discharged per Well: 389 bbls
Impact Area per Well: 1.9 kmA2
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Avg. Cone, of Pollutant Pollutant Pollutant Sediment Sediment Partition Estimated Pore
Pollutants in Loadings per Well (Ibs) Loadings per Well Concentration Coefficient or Leach Water Cone.
Drilling Waste Current Technology (11%) (mg) (mg poll./kg sed.) Percentage Factors (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
51,818
514,150
565,968
74,062
3.91e-01
2.13e-01
5.06e-01
2.81e-05
5.70e-02
5.18e-03
2.95e-01
3.68e-01
3.63e-02
1.24e+01
9.69e-01
1.82e+00
7.00e-01
5.70e-02
3.63e-02
6.22e-02
1.04e+01
4.70e+02
6.22e+03
7.95e+02
7.57e-01
4.53e+00
2.20e+00
2.07e+01
2.49e+00
3.15e+00
2.48e-04
4.09e+00
3.56e-03
1.77e+05
9.67e+04
2.29e+05
1.27e+01
2.59e+04
2.35e+03
1.34e+05
1.67e+05
1.65e+04
5.64e+06
4.40e+05
8.25e+05
3.17e+05
2.59e+04
1.65e+04
2.82e+04
4.71e+06
2.13e+08
2.82e+09
3.61e+08
3.43e+05
2.06e+06
9.98e+05
9.39e+06
1.13e+06
1.43e+06
1.12e+02
1.86e+06
1.61e+03
6,629
0.0026
0.0014
0.0034
1.89e-07
0.0004
3.48e-05
0.0020
0.0025
0.0002
0.0836
0.0065
0.0122
0.0047
0.0004
0.0002
0.0004
0.0699
3.1606
41.8164
5.3470
0.0051
0.0305
0.0148
0.1392
0.0168
0.0212
1.67e-06
0.0275
2.39e-05
0.0795
0.0407
0.0113
11.3380
0.1100
0.0180
1.0000
0.0050
1.0000
0.0340
0.0063
0.0200
0.0430
1.0000
1.0000
1.0000
0.0041
1.0000
0.0021
0.1300
2.28e-04
6.38e-05
4.19e-05
2.33e-06
4.61e-05
6.85e-07
2.17e-03
1.35e-05
2.66e-04
3.10e-03
4.49e-05
2.68e-04
2.20e-04
4.18e-04
2.66e-04
4.57e-04
3.12e-04
3.45e+00
9.59e-02
7.59e-01
(a) Estimated pore water cone. = Poll, sediment cone. * Sed. partition coeff. or leach factor * 35.5 kg of sediment / 32.5 liter pore water unit volume
F-l
-------
Exhibit F-2. Gulf of Mexico Shallow Water Development Model Well
Pore Water Concentrations for Calculation of Shrimp Tissue Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination in SBF
Dry Cuttings Generated per Well: 514,150 Ibs
Whole Drilling Fluid Discharged Per Well: 223 bbls
Impact Area per Well: 1.9 kmA2
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Avg. Cone, of Pollutant Pollutant Pollutant Sediment Sediment Partition Estimated Pore
Pollutants in Loadings per Well (Ibs) Loadings per Well Concentration Coefficient or Leach Water Cone.
Drilling Waste Discharge Option (7%) (mg) (mg poll./kg sed.) Percentage Factors (mg/1) (a)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
29,661
514,150
543,811
42,418
2.24e-01
1.22e-01
2.90e-01
1.61e-05
3.26e-02
2.97e-03
1.69e-01
2.11e-01
2.08e-02
7.12e+00
5.55e-01
1.04e+00
4.00e-01
3.26e-02
2.08e-02
3.56e-02
5.95e+00
2.69e+02
3.56e+03
4.55e+02
4.33e-01
2.60e+00
1.26e+00
1.19e+01
1.43e+00
1.80e+00
1.42e-04
2.35e+00
2.04e-03
101,605
55,338
131,542
7
14,787
1,347
76,657
95,708
9,435
3,229,582
251,744
471,737
181,437
14,787
9,435
16,148
2,698,878
122,016,517
1,614,791,080
206,384,815
196,406
1,179,342
571,527
5,397,757
648,638
816,467
64
1,065,944
925
3,796.48
1.51e-02
8.20e-03
1.95e-02
1.04e-06
2.19e-03
2.00e-04
1.14e-02
1.42e-02
1.40e-03
4.79e-01
3.73e-02
6.99e-02
2.69e-02
2.19e-03
1.40e-03
2.39e-03
4.00e-01
1.81e+01
2.39e+02
3.06e+01
2.91e-02
1.75e-01
8.47e-02
8.00e-01
9.62e-02
1.21e-01
9.49e-06
1.58e-01
0
0.0795
0.0407
0.0113
11.3380
0.1100
0.0180
1.0000
0.0050
1.0000
0.0340
0.0063
0.0200
0.0430
1.0000
1.0000
1.0000
0.0041
1.0000
0.0021
0.1300
5.62e-02
1.10e-03
2.40e-05
1.34e-06
2.63e-05
3.92e-07
1.24e-03
7.73e-06
1.53e-04
1.78e-03
2.57e-05
1.53e-04
1.27e-04
2.39e-04
1.53e-04
2.61e-04
1.79e-04
1.98e+00
5.49e-02
4.34e-01
(a) Estimated pore water cone. = Poll, sediment cone. * Sed. partition coeff. or leach factor * 35.5 kg of sediment / 32.5 liter pore water unit volume
F-2
-------
Exhibit F-3. Gulf of Mexico Shallow Exploratory Model Well
Pore Water Concentrations for Calculation of Shrimp Tissue Pollutant Concentrations: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 1,077,440 Ibs
Whole Drilling Fluid Discharged per Well: 814 bbls
Impact Area per Well: 1.9 kmA2
Pollutant Name
Conventional Pollutants
Avg. Cone, of Pollutant Pollutant Pollutant Sediment Sediment Partition Estimated Pore
Pollutants in Loadings per Well (Ibs) Loadings per Well Concentration Coefficient or Leach Water Cone.
Drilling Waste Current Technology (11%) (mg) (mg poll./kg sed.) Percentage Factors (mg/1) (a)
Ibs/lb disch. cuttings
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
108,588
1,077,440
1,186,028
155,202
8.18e-01
4.46e-01
1.06e+00
5.88e-05
1.19e-01
1.09e-02
6.19e-01
7.71e-01
7.60e-02
2.61e+01
2.03e+00
3.81e+00
1.47e+00
1.19e-01
7.60e-02
1.30e-01
2.18e+01
9.85e+02
1.30e+04
1.67e+03
1.59e+00
9.50e+00
4.61e+00
4.33e+01
5.21e+00
6.59e+00
5.18e-04
8.56e+00
7.45e-03
3.71e+05
2.02e+05
4.80e+05
2.67e+01
5.42e+04
4.93e+03
2.81e+05
3.50e+05
3.45e+04
1.18e+07
9.21e+05
1.73e+06
6.65e+05
5.42e+04
3.45e+04
5.91e+04
9.88e+06
4.47e+08
5.91e+09
7.56e+08
7.19e+05
4.31e+06
2.09e+06
1.96e+07
2.36e+06
2.99e+06
2.35e+02
3.88e+06
3.38e+03
13,891.64
5.50e-03
3.00e-03
7.12e-03
3.95e-07
8.03e-04
7.30e-05
4.16e-03
5.18e-03
5.11e-04
1.75e-01
1.37e-02
2.56e-02
9.86e-03
8.03e-04
5.11e-04
8.76e-04
1.46e-01
6.62e+00
8.76e+01
1.12e+01
1.07e-02
6.39e-02
3.10e-02
2.91e-01
3.51e-02
4.43e-02
3.49e-06
5.76e-02
5.01e-05
0.0795
0.0407
0.0113
11.3380
0.1100
0.0180
1.0000
0.0050
1.0000
0.0340
0.0063
0.0200
0.0430
1.0000
1.0000
1.0000
0.0041
1.0000
0.0021
0.1300
4.77e-04
1.33e-04
8.78e-05
4.89e-06
9.66e-05
1.43e-06
4.54e-03
2.83e-05
5.58e-04
6.51e-03
9.39e-05
5.60e-04
4.63e-04
8.77e-04
5.58e-04
9.57e-04
6.55e-04
7.23e+00
2.00e-01
1.59e+00
(a) Estimated pore water cone. = Poll, sediment cone. * Sed. partition coeff. or leach factor * 35.5 kg of sediment / 32.5 liter pore water unit volume
F-3
-------
Exhibit F-4. Gulf of Mexico Shallow Exploratory Model Well
Pore Water Concentrations for Calculation of Shrimp Tissue Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination in
Dry Cuttings Generated per Well: 1,077,440 Ibs
Whole Drilling Fluid Discharged Per Well: 466 bbls
Impact Area per Well: 1.9 kmA2
SBF
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Avg. Cone, of Pollutant Pollutant Pollutant Sediment Sediment Partition Estimated Pore
Pollutants in Loadings per Well (Ibs) Loadings per Well Concentration Coefficient or Leach Water Cone.
Drilling Waste Discharge Option (7%) (mg) (mg poll./kg sed.) Percentage Factors (mg/1)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
0.0010052
0.0005483
0.0013004
7.22e-08
Ibs/lb dry SBF
0.0000011
0.0000001
0.0000057
0.0000071
0.0000007
0.0002400
0.0000187
0.0000351
0.0000135
0.0000011
0.0000007
0.0000012
0.0002005
Ibs/lb dry SBF or bbl SBF
0.0090699
0.1200000
0.0153443
0.0000146
0.0000875
0.0056587
0.0531987
0.0064038
0.0080909
0.0000006
0.0105160
0.0000092
62,158
1,077,440
1,139,598
88,890
0.4684
0.2555
0.6060
3.37e-05
0.0684
0.0062
0.3543
0.4413
0.0435
14.9179
1.1624
2.1817
0.8391
0.0684
0.0435
0.0746
12.4627
563.7668
7,458.9600
953.7710
0.9075
5.4388
2.6369
24.7906
2.9842
3.7703
0.0003
4.9005
0.0043
212,463
115,893
274,877
15
31,026
2,812
160,708
200,171
19,731
6,766,655
527,257
989,604
380,610
31,026
19,731
33,838
5,652,993
255,720,674
3,383,332,043
432,623,849
411,636
2,467,002
1,196,079
11,244,843
1,353,612
1,710,182
136
2 222 832
1,950
7,955.74
3.15e-02
1.72e-02
4.08e-02
2.22e-06
4.60e-03
4.17e-04
2.38e-02
2.97e-02
2.93e-03
l.OOe+00
7.82e-02
1.47e-01
5.64e-02
4.60e-03
2.93e-03
5.02e-03
8.38e-01
3.79e+01
5.02e+02
6.41e+01
6.10e-02
3.66e-01
1.77e-01
1.67e+00
2.01e-01
2.54e-01
2.02e-05
3.30e-01
2.89e-04
0.0795
0.0407
0.0113
11.3380
0.1100
0.0180
1.0000
0.0050
1.0000
0.0340
0.0063
0.0200
0.0430
1.0000
1.0000
1.0000
0.0041
1.0000
0.0021
0.1300
2.73e-04
7.64e-05
5.04e-05
2.81e-06
5.53e-05
8.21e-07
2.60e-03
1.62e-05
3.20e-04
3.72e-03
5.37e-05
3.20e-04
2.65e-04
5.02e-04
3.20e-04
5.02e-04
3.76e-04
4.14e+00
1.15e-01
9.11e-01
(a) Estimated pore water cone. = Poll, sediment cone. * Sed. partition coeff. or leach factor * 35.5 kg of sediment / 32.5 liter pore water unit volume
F-4
-------
Exhibit F-5. California Shallow Water Development Model Well
Pore Water Concentrations for Calculation of Shrimp Tissue Pollutant Concentrations: Current Technology
Technology = Discharge Assuming 11% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol.) Crude Contamination in SBF
Dry Cuttings Generated per Well: 514,150 Ibs
Whole Drilling Fluid Discharged per Well: 389 bbls
Impact Area per Well: 1.9 kmA2
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutant Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Berylium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenlos
Total biphenyls
Total dibenzothiophenes
Avg. Cone, of Pollutant Pollutant Pollutant Sediment Sediment Partition Estimated Pore
Pollutants in Loadings per Well (Ibs) Loadings per Well Concentration Coefficient or Leach Water Cone.
Drilling Waste Current Technology (11%) (mg) (mg poll./kg sed.) Percentage Factors (mg/kg)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
51,818
514,150
565,968
74,062
3.91e-01
2.13e-01
5.06e-01
2.81e-05
5.70e-02
5.18e-03
2.95e-01
3.68e-01
3.63e-02
1.24e+01
9.69e-01
1.82e+00
7.00e-01
5.70e-02
3.63e-02
6.22e-02
1.04e+01
4.70e+02
6.22e+03
7.95e+02
7.57e-01
4.53e+00
2.20e+00
2.07e+01
2.49e+00
3.15e+00
2.48e-04
4.09e+00
3.56e-03
1.77e+05
9.67e+04
2.29e+05
1.27e+01
2.59e+04
2.35e+03
1.34e+05
1.67e+05
1.65e+04
5.64e+06
4.40e+05
8.25e+05
3.17e+05
2.59e+04
1.65e+04
2.82e+04
4.71e+06
2.13e+08
2.82e+09
3.61e+08
3.43e+05
2.06e+06
9.98e+05
9.39e+06
1.13e+06
1.43e+06
1.12e+02
1.86e+06
1.61e+03
4,130
0.0026
0.0014
0.0034
1.89e-07
0.0004
3.48e-05
0.0020
0.0025
0.0002
0.0836
0.0065
0.0122
0.0047
0.0004
0.0002
0.0004
0.0699
3.1606
41.8164
5.3470
0.0051
0.0305
0.0148
0.1392
0.0168
0.0212
1.67e-06
0.0275
2.39e-05
0.0795
0.0407
0.0113
11.3380
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
2.28e-04
6.38e-05
4.19e-05
2.34e-06
4.61e-05
6.85e-07
2.17e-03
1.35e-05
2.66e-04
3.10e-03
4.49e-05
2.68e-04
2.21e-04
4.18e-04
2.67e-04
4.57e-04
3.12e-04
3.45e+00
9.59e-02
7.59e-01
(a) Estimated pore water cone. = Poll, sediment cone. * Sed. partition coeff. or leach factor * 35.5 kg of sediment / 32.5 liter pore water unit volume
F-5
-------
Exhibit F-6. California Shallow Water Development Model Well
Pore Water Concentrations for Calculation of Shrimp Tissue Pollutant Concentrations: Discharge Option
Technology = Discharge Assuming 7% (wt) Base Fluid Retention on Discharged Cuttings and 0.2% (vol) Crude Contamination in SBF
Dry Cuttings Generated per Well: 514,150 Ibs
Whole Drilling Fluid Discharged per Well: 223 bbls
Impact Area per Well: 1.9 kmA2
Pollutant Name
Conventional Pollutants
TSS (associated with adhering SBF)
TSS (associated with dry cuttings)
TSS (total)
Total Oil (synthetic plus crude)
Priority Pollutants, Organics
Naphthalene
Fluorene
Phenanthrene
Phenol
Priority Pollutants, Metals
Cadmium
Mercury
Antimony
Arsenic
Berylium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Non-Conventional Pollutants
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiophenes
Avg. Cone, of Pollutant Pollutant Pollutant Sediment Sediment Partition Estimated Pore
Pollutants in Loadings per Well (Ibs) Loadings per Well Concentration Coefficient or Leach Water Cone.
Drilling Waste Discharge Option (7%) (mg) (mg poll./kg sed.) Percentage Factors (mg/kg)
Ibs/lb disch. cuttings
Ibs/bbl drilling fluid
l.Ole-03
5.48e-04
1.30e-03
7.22e-08
Ibs/lb dry SBF
1.10e-06
l.OOe-07
5.70e-06
7.10e-06
7.00e-07
2.40e-04
1.87e-05
3.51e-05
1.35e-05
1.10e-06
7.00e-07
1.20e-06
2.00e-04
Ibs/lb dry SBF or bbl SBF
9.07e-03
1.20e-01
1.53e-02
1.46e-05
8.75e-05
5.66e-03
5.32e-02
6.40e-03
8.09e-03
6.37e-07
1.05e-02
9.15e-06
29,661
514,150
543,811
42,418
2.24e-01
1.22e-01
2.90e-01
1.61e-05
3.26e-02
2.97e-03
1.69e-01
2.11e-01
2.08e-02
7.12e+00
5.55e-01
1.04e+00
4.00e-01
3.26e-02
2.08e-02
3.56e-02
5.95e+00
2.69e+02
3.56e+03
4.55e+02
4.33e-01
2.60e+00
1.26e+00
1.19e+01
1.43e+00
1.80e+00
1.42e-04
2.35e+00
2.04e-03
1.02e+05
5.53e+04
1.32e+05
7.31e+00
1.48e+04
1.35e+03
7.67e+04
9.57e+04
9.43e+03
3.23e+06
2.52e+05
4.72e+05
1.81e+05
1.48e+04
9.43e+03
1.61e+04
2.70e+06
1.22e+08
1.61e+09
2.06e+08
1.96e+05
1.18e+06
5.72e+05
5.40e+06
6.49e+05
8.16e+05
6.44e+01
1.07e+06
9.25e+02
2,365.35
1.51e-03
8.20e-04
1.95e-03
1.08e-07
2.19e-04
2.00e-05
1.14e-03
1.42e-03
1.40e-04
4.79e-02
3.73e-03
6.99e-03
2.69e-03
2.19e-04
1.40e-04
2.39e-04
4.00e-02
1.81e+00
2.39e+01
3.06e+00
2.91e-03
1.75e-02
8.47e-03
8.00e-02
9.62e-03
1.21e-02
9.55e-07
1.58e-02
1.37e-05
0.0795
0.0407
0.0113
11.3380
0.1100
0.0180
0.0050
0.0340
0.0063
0.0200
0.0430
0.0041
0.0021
0.1300
1.31e-04
3.66e-05
2.40e-05
1.34e-06
2.63e-05
3.92e-07
1.24e-03
7.73e-06
1.53e-04
1.78e-03
2.57e-05
1.53e-04
1.27e-04
2.39e-04
1.53e-04
2.61e-04
1.79e-04
1.98e+00
5.49e-02
4.35e-01
(a) Estimated pore water cone. = Poll, sediment cone. * Sed. partition coeff. or leach factor * 35.5 kg of sediment / 32.5 liter pore water unit volume
F-6
-------
APPENDIX G
CALCULATION OF
SHRIMP TISSUE POLLUTANT CONCENTRATIONS
-------
G-l
Exhibit G-l. Commercial Shrimp Tissue Pollutant Concentrations - Gulf of Mexico
Shallow Water Development Model Well, Current Technology
(a)
See
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
(A)
Pollutant
Sediment
Concentration
(mg poll/kg sed.)
2.60e-03
1.40e-03
3.40e-03
1.89e-07
4.00e-04
3.48e-05
2.00e-03
2.50e-03
2.00e-04
8.36e-02
6.50e-03
1.20e-02
4.70e-03
4.00e-04
2.00e-04
4.00e-04
6.99e-02
3.16e+00
4.18e+01
5.34e+00
5.10e-03
3.05e-02
1.48e-02
1.39e-01
1.68e-02
2.12e-02
1.67e-06
2.75e-02
2.39e-05
(B)
Sediment
Partition
Coeff.Al or
Leach Factor
0.0795
0.0407
0.0113
11.338
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
(C)
Estimated
Pore
Water Cone.
(mg/1)
2.28e-04
6.38e-05
4.19e-05
2.33e-06
4.61e-05
6.85e-07
2.17e-03
1.35e-05
2.66e-04
3.10e-03
4.49e-05
2.68e-04
2.20e-04
4.18e-04
2.66e-04
4.57e-04
3.12e-04
3.45e+00
9.59e-02
7.59e-01
(D)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(E)
Shrimp
Tissue
Cone.
(mg/kg)
9.80e-02
1.93e-03
l.lle-01
3.30e-06
2.70e-03
3.45e-03
1.99e-03
5.44e-04
4.63e-03
4.55e-02
1.48e-03
1.20e-02
9.51e-03
1.84e-03
1.22e-04
4.85e-02
1.35e-02
7.30e+02
There are no BCFs for specific SBF compounds.
Appendix F for pollutant sediment concentration calculations.
Table Calculations:
C= A * B (B is assumed to be 1 unless otherwise noted) * 35.5 kg sediment / 32.5 liter pore water
unit volume
E= C * D * 1.1% (pore water cone. * BCF * shrimp lipid percent)
-------
G-2
Exhibit G-2. Commercial Shrimp Tissue Pollutant Concentrations - Gulf of Mexico
Shallow Water Development Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiotjhenes
(A)
Pollutant
Sediment
Concentration
(mg poll/kg sed.)
1.50e-03
8.00e-04
2.00e-03
1.08e-07
2.00e-04
1.99e-05
1.10e-03
1.40e-03
l.OOe-04
4.79e-02
3.70e-03
7.00e-03
2.70e-03
2.00e-04
l.OOe-04
2.00e-04
4.00e-02
1. 81e+00
2.39e+01
3.06e+00
2.90e-03
1.75e-02
8.50e-03
7.98e-02
9.60e-03
1.21e-02
9.55e-07
1.58e-02
1.37e-05
(B)
Sediment
Partition
Coeff.Al or
Leach Factor
0.0795
0.0407
0.0113
11.338
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
(C)
Estimated
Pore
Water Cone.
(mg/1)
1.31e-04
3.66e-05
2.40e-05
1.34e-06
2.63e-05
3.92e-07
1.24e-03
7.73e-06
1.53e-04
1.78e-03
2.57e-05
1.53e-04
1.27e-04
2.39e-04
1.53e-04
2.61e-04
1.79e-04
1.98e+00
5.49e-02
4.34e-01
(D)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(E)
Shrimp Tissue
Cone.
(mg/kg)
5.62e-02
1.10e-03
6.38e-02
1.89e-06
1.54e-03
1.97e-03
1.14e-03
3.12e-04
2.65e-03
2.60e-02
8.46e-04
6.86e-03
5.44e-03
1.05e-03
6.98e-05
2.78e-02
7.71e-03
4.18e+02
(a) There are no BCFs for specific SBF compounds.
See Appendix F for pollutant sediment concentration calculations.
Table Calculations:
C= A * B (B is assumed to be 1 unless otherwise noted) * 35.5 kg sediment / 32.5 liter pore water
unit volume
E= C * D * 1.1% (pore water cone. * BCF * shrimp lipid percent)
-------
G-3
Exhibit G-3. Commercial Shrimp Tissue Pollutant Concentrations - Gulf of Mexico
Shallow Water Exploratory Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
(A)
Pollutant
Sediment
Concentration
(mg poll./kg sed.)
5.50e-03
3.00e-03
7.10e-03
3.95e-07
8.00e-04
7.30e-05
4.20e-03
5.20e-03
5.00e-04
1.75e-01
1.14e-02
2.56e-02
9.90e-03
8.00e-04
5.00e-04
9.00e-04
1.466-01
6.62e+00
8.76e+01
1.12e+01
1.07e-02
6.39e-02
3.10e-02
2.91e-01
3.51e-02
4.43e-02
3.49e-06
5.76e-02
5.01e-05
(B)
Sediment
Partition
Coeff.Al or
Leach Factor
0.0795
0.0407
0.0113
11.338
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
(C)
Estimated Pore
Water Cone.
(mg/1)
4.77e-04
1.33e-04
8.78e-05
4.89e-06
9.66e-05
1.43e-06
4.54e-03
2.83e-05
5.58e-04
6.51e-03
9.39e-05
5.60e-04
4.63e-04
8.77e-04
5.58e-04
9.57e-04
6.55e-04
7.23e+00
2.00e-01
1.59e+00
(D)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(E)
Shrimp Tissue
Cone.
(mg/kg)
2.05e-01
4.03e-03
2.33e-01
6.91e-06
5.65e-03
7.23e-03
4.16e-03
1.14e-03
9.71e-03
9.53e-02
3.10e-03
2.51e-02
1.99e-02
3.86e-03
2.56e-04
1.026-01
2.82e-02
1.53e+02
(a) There are no BCFs for specific SBF compounds.
See Appendix F for pollutant sediment concentration calculations.
Table Calculations:
C= A * B (B is assumed to be 1 unless otherwise noted) * 35.5 kg sediment / 32.5 liter pore water
unit volume
E= C * D * 1.1% (pore water cone. * BCF * shrimp lipid percent)
-------
G-4
Exhibit G-4. Commercial Shrimp Tissue Pollutant Concentrations - Gulf of Mexico
Shallow Water Exploratory Model Well, Discharge Option
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
(A)
Pollutant
Sediment
Concentration
(mg poll/kg sed.)
3.20e-03
1.70e-03
4.10e-03
2.26e-07
5.00e-04
4.18e-05
2.40e-03
3.00e-03
3.00e-04
l.OOe-01
7.80e-03
1.47e-02
5.60e-03
5.00e-04
3.00e-04
5.00e-04
8.38e-02
3.79e+00
5.02e+01
6.41e+00
6.10e-03
3.66e-02
1.77e-02
1.676-01
2.01e-02
2.54e-02
2.00e-06
3.30e-02
2.87e-05
(B)
Sediment
Partition
Coeff.Al or
Leach Factor
0.0795
0.0407
0.0113
11.338
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
(C)
Estimated Pore
Water Cone.
(mg/1)
2.73e-04
7.64e-05
5.04e-05
2.81e-06
5.53e-05
8.21e-07
2.60e-03
1.62e-05
3.20e-04
3.72e-03
5.37e-05
3.20e-04
2.65e-04
5.02e-04
3.20e-04
5.48e-04
3.76e-04
4.14e+00
1.156-01
9.11e-01
(D)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(E)
Shrimp Tissue
Cone.
(mg/kg)
1.176-01
2.31e-03
1.336-01
3.95e-06
3.24e-03
4.14e-03
2.38e-03
6.53e-04
5.56e-03
5.46e-02
1.77e-03
1.44e-02
1.14e-02
2.21e-03
1.46e-04
5.82e-02
1.62e-02
8.76e+02
(a) There are no BCFs for specific SBF compounds.
See Appendix F for pollutant sediment concentration calculations.
Table Calculations:
C= A * B (B is assumed to be 1 unless otherwise noted) * 35.5 kg sediment / 32.5 liter pore water
unit volume
E= C * D * 1.1% (pore water cone. * BCF * shrimp lipid percent)
-------
G-5
Exhibit G-5. Commercial Shrimp Tissue Pollutant Concentrations - Offshore California
Shallow Development Model Well, Current Technology
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
(A)
Pollutant
Sediment
Concentration
(mg poll./kg sed.)
2.60e-03
1.40e-03
3.40e-03
1.89e-07
4.00e-04
3.48e-05
2.00e-03
2.50e-03
2.00e-04
8.36e-02
6.50e-03
1.22e-02
4.70e-03
4.00e-04
2.00e-04
4.00e-04
6.99e-02
3.16e+00
4.18e+01
5.35e+00
5.10e-03
3.05e-02
1.48e-02
1.39e-01
1.68e-02
2.12e-02
1.67e-06
2.75e-02
2.39e-05
(B)
Sediment
Partition
Coeff.Al or
Leach Factor
0.0795
0.0407
0.0113
11.338
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
(C)
Estimated
Pore
Water Cone.
(mg/1)
2.28e-04
6.38e-05
4.19e-05
2.34e-06
4.61e-05
6.85e-07
2.17e-03
1.35e-05
2.66e-04
3.10e-03
4.49e-05
2.68e-04
2.21e-04
4.18e-04
2.67e-04
4.57e-04
3.12e-04
3.45e+00
9.59e-02
7.59e-01
(D)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(E)
Shrimp Tissue
Cone.
(mg/kg)
9.80e-02
1.93e-03
l.lle-01
3.30e-06
2.70e-03
3.45e-03
1.99e-03
5.44e-04
4.63e-03
4.55e-02
1.48e-03
1.20e-02
9.51e-03
1.84e-03
1.22e-04
4.85e-02
1.35e-02
7.31e+02
(a) There are no BCFs for specific SBF compounds.
See Appendix F for pollutant sediment concentration calculations.
Table Calculations:
C= A * B (B is assumed to be 1 unless otherwise noted) * 35.5 kg sediment / 32.5 liter pore water
unit volume
E= C * D * 1.1% (pore water cone. * BCF * shrimp lipid percent)
-------
G-6
Exhibit G-6. Commercial Shrimp Tissue Pollutant Concentrations - Offshore California,
Shallow Water Development Model Well, Discharge Option
(a)
See
Pollutant
Naphthalene
Fluorene
Phenanthrene
Phenol
Cadmium
Mercury
Antimony
Arsenic
Beryllium
Chromium
Copper
Lead
Nickel
Selenium
Silver
Thallium
Zinc
Aluminum
Barium
Iron
Tin
Titanium
Alkylated benzenes
Alkylated naphthalenes
Alkylated fluorenes
Alkylated phenanthrenes
Alkylated phenols
Total biphenyls
Total dibenzothiorjhenes
(A)
Pollutant
Sediment
Concentration
(mg poll./kg sed.)
1.50e-03
8.00e-04
2.00e-03
1.08e-07
2.00e-04
1.99e-05
l.lOe-03
1.40e-03
l.OOe-04
4.79e-02
3.70e-03
7.00e-03
2.70e-03
2.00e-04
l.OOe-04
2.00e-04
4.00e-02
l.Sle+00
2.39e+01
3.06e+00
2.90e-03
1.75e-02
8.50e-03
7.98e-02
9.60e-03
1.21e-02
9.55e-07
1.58e-02
1.37e-05
(B)
Sediment
Partition
Coeff.Al or
Leach Factor
0.0795
0.0407
0.0113
11.338
0.11
0.018
0.005
0.034
0.0063
0.02
0.043
0.0041
0.0021
0.13
(C)
Estimated
Pore
Water Cone.
(mg/1)
1.31e-04
3.66e-05
2.40e-05
1.34e-06
2.63e-05
3.92e-07
1.24e-03
7.73e-06
1.53e-04
1.78e-03
2.57e-05
1.53e-04
1.27e-04
2.39e-04
1.53e-04
2.61e-04
1.79e-04
1.98e+00
5.49e-02
4.35e-01
(D)
BCF
(I/kg)
(a)
426
30
2630
1.4
64
5500
1
44
19
16
36
49
47
4.8
0.5
116
47
231
(E)
Shrimp
Tissue
Cone.
(mg/kg)
5.62e-02
1.10e-03
6.38e-02
1.89e-06
1.54e-03
1.97e-03
1.40e-03
3.12e-04
2.65e-03
2.60e-02
8.46e-04
6.86e-03
5.44e-03
1.05e-03
6.98e-05
2.78e-02
7.71e-03
4.18e+02
There are no BCFs for specific SBF compounds.
Appendix F for pollutant sediment concentration calculations.
Table Calculations:
C= A * B (B is assumed to be 1 unless otherwise noted) * 35.5 kg sediment / 32.5 liter pore water
unit volume
E= C * D * 1.1% (pore water cone. * BCF * shrimp lipid percent)
------- |