Bioaccumulation in marine organisms effect of contaminants from oil well produced water

Tai Lieu Chat Luong


BIOACCUMULATION IN MARINE ORGANISMS
Effect of Contaminants from Oil Well Produced Water


This Page Intentionally Left Blank


BIOACCUMULATION IN
MARINE ORGANISMS
Effect of C o n t a m i n a n t s
from Oil Well P r o d u c e d W a t e r

JERRY M. NEFF, Ph.D.
Battelle, Coastal Resources and Environmental Management,
Duxbury, Massachusetts 02332, USA

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Contents

Preface

xi

.................................................

Acknowledgements

xv

................................................

C H A P T E R 1: P R O D U C E D W A T E R . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1

1

1
1

C o m p o s i t i o n o f P r o d u c e d Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1.1
Sources and Treatment o f Produced Water . . . . . . . . . . . . . . . . .
1.1.2
Naturally-Occurring C h e m i c a l s in Produced Water . . . . . . . . . .
1.1.3
Production C h e m i c a l s in P r o d u c e d Water . . . . . . . . . . . . . . . . . .

16

1.2

Volumes o f P r o d u c e d Water Discharged to the Ocean

..............

18

1.3

Fate o f C h e m i c a l s from Produced Water in the O c e a n

..............

19
19

1.3.1
1.3.2
1.3.3
1.4

M o d e l e d Dilution o f the Produced Water Plume . . . . . . . . . . . . .
Fate o f C h e m i c a l s in Produced Water Plumes . . . . . . . . . . . . . .
Degradation o f Produced Water Chemicals in the O c e a n . . . . . .

Toxicity o f P r o d u c e d Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.4.1
Toxicity o f W h o l e P r o d u c e d Water . . . . . . . . . . . . . . . . . . . . . . .
1.4.2
Causes o f P r o d u c e d Water Toxicity . . . . . . . . . . . . . . . . . . . . . .
1.4.3
Toxicity o f P r o d u c e d Water Additives . . . . . . . . . . . . . . . . . . . .

C H A P T E R 2: B I O A C C U M U L A T I O N M E C H A N I S M S

...................

2

22
27
30
30
33
34
37

2.1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37

2.2

Bioavailability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

37

2.2.1
2.2.2
2.2.3

37
38
42

Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Organic C h e m i c a l s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2.3

Bioaccumulation

..........................................

2.4

Bioconcentration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.1
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.2
N o n p o l a r Organic C h e m i c a l s . . . . . . . . . . . . . . . . . . . . . . . . . . .

43
44
44
44


vi Bioaccumulation in Marine Organisms

2.4.3
2.4.4
2.5

46
47

Ionizable Organic Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . .
Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

50
50
51
54

Biomagnification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.1
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.2
Organic Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.3
Metals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

57

C H A P T E R 3" ARSENIC IN THE OCEAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1

Arsenic in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

57

3.2

Arsenic in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

60

3.3

Bioaccumulation and Biotransformation of Arsenic . . . . . . . . . . . . . . . .

62

3.4

Concentrations of Arsenic in Tissues of Marine Organisms

68

3.5

Toxicity of Arsenic to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . .

72

3.6

Environmental Effects of Arsenic in Produced Water . . . . . . . . . . . . . . .

76

C H A P T E R 4: BARIUM IN THE O C E A N

..........

.............................

79

4.1

Barium in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

79

4.2

Barium in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

81

4.3

Bioaccumulation of Barium by Marine Organisms . . . . . . . . . . . . . . . . .

82
83

4.4

Concentrations of Barium in Tissues of Marine Organisms

4.5

Toxicity of Barium to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . .

84

4.6

Environmental Effects of Barium in Produced Water . . . . . . . . . . . . . . .

86

C H A P T E R 5" C A D M I U M IN THE O C E A N

..........

...........................

89

Cadmium in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

89

5.2

Cadmium in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

92

5.3

Bioaccumulation of Cadmium by Marine Organisms . . . . . . . . . . . . . . .

93

5.4

Concentrations of Cadmium in Tissues of Marine Organisms . . . . . . . . .

97

5.5

Toxicity of Cadmium to Marine Organisms . . . . . . . . . . . . . . . . . . . . . .

100

5.6

Environmental Effects of Cadmium in Produced Water . . . . . . . . . . . . .

102

5.1

C H A P T E R 6: MERCURY IN THE O C E A N . . . . . . . . . . . . . . . . . . . . . . . . . . . .

103

6.1

Mercury in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

103

6.2

Mercury in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

108

6.3

Bioaccumulation of Mercury by Marine Organisms . . . . . . . . . . . . . . . .

112

6.4

Concentrations of Mercury in Tissues of Marine Organisms . . . . . . . . . .

117

6.5

Toxicity of Mercury to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . .

125

6.6

Environmental Effects of Mercury in Produced Water . . . . . . . . . . . . . .

129


Contents vii

C H A P T E R 7: C H R O M I U M IN THE O C E A N
7.1

............

..............

131

Chromium in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

131

7.2

Chromium in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

133

7.3

Bioaccumulation of Chromium by Marine Organisms . . . . . . . . . . . . . .

135

7.4

Concentrations of Chromium in Tissues of Marine Organisms . . . . . . . .

137

7.5

Toxicity of Chromium to Marine Organisms

141

7.6

Environmental Effects of Chromium in Produced Water . . . . . . . . . . . . .

.....................

C H A P T E R 8: COPPER IN THE O C E A N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

142
145

8.1

Copper in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

145

8.2

Copper in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

148

8.3

Bioaccumulation of Copper by Marine Organisms . . . . . . . . . . . . . . . . .

150

8.4

Concentrations of Copper in Tissues of Marine Organisms

153

8.5

Toxicity of Copper to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . .

157

8.6

Environmental Effects of Copper in Produced Water . . . . . . . . . . . . . . .

159

..........

C H A P T E R 9: LEAD IN THE O C E A N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

161

9.1

Lead in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

161

9.2

Lead in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

164

9.3

Bioaccumulation of Lead by Marine Organisms . . . . . . . . . . . . . . . . . . .

166

9.4

Concentrations of Lead in Tissues of Marine Organisms

167

9.5

Toxicity of Lead to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . .

170

9.6

Environmental Effects of Lead in Produced Water . . . . . . . . . . . . . . . . .

173

C H A P T E R 10: ZINC IN THE O C E A N
10.1

............

...............................

Zinc in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10.2 Zinc in Marine Sediments

...................................

175
175
177

10.3

Bioaccumulation of Zinc by Marine Organisms . . . . . . . . . . . . . . . . . . .

179

10.4

Concentrations of Zinc in Tissues of Marine Organisms . . . . . . . . . . . . .

182

10.5

Toxicity of Zinc to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . .

186

10.6

Environmental Effects of Zinc in Produced Water

188

.................

C H A P T E R 11: R A D I U M ISOTOPES IN THE O C E A N . . . . . . . . . . . . . . . . . . .

191

11.1

Radium in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

191

11.2

Radium in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

194

11.3

Bioaccumulation of Radium by Marine Organisms

195

11.4

Concentrations of Radium in Tissues of Marine Organisms . . . . . . . . . .

198

11.5

Toxicity of Radium to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . .

199

................

11.6 Environmental Effects of Radium in Produced Water . . . . . . . . . . . . . . .

200


viii Bioaccumulation in Marine Organisms
CHAPTER 12: PHENOLS IN THE OCEAN
12.1

...........................

203

Phenols in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

203

12.2 Phenols in Marine Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

206

12.3 Bioaccumulation of Phenols by Marine Organisms

207

................

12.4 Concentrations of Phenols in Tissues of Marine Organisms . . . . . . . . . .

209

12.5 Toxicity of Phenols to Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . .

210

12.6 Environmental Effects of Phenols in Produced Water . . . . . . . . . . . . . . .

213

CHAPTER 13: DI(2-ETHYLHEXYL)PHTHALATE IN THE OCEAN

.......

215

13.1 Di(2-ethylhexyl)phthalate in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . .

215

13.2 Di(2-ethylhexyl)phthalate in Marine Sediments . . . . . . . . . . . . . . . . . . .

218

13.3 Bioaccumulation of Di(2-ethylhexyl)phthalate by Marine Organisms . . .

219

13.4 Concentrations of Di(2-ethylhexyl)phthalate in Tissues of
Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

220

13.5 Toxicity of Di(2-ethylhexyl)phthalate to Marine Organisms . . . . . . . . . .

221

13.6 Environmental Effects of Di(2-ethylhexyl)phthalate in Produced W a t e r . . . 223
CHAPTER 14: MONOCYCLIC AROMATIC HYDROCARBONS
IN THE OCEAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14.1

225

Monocyclic Aromatic Hydrocarbons in Seawater . . . . . . . . . . . . . . . . . .
225
14.1.1 Sources of Monocyclic Aromatic Hydrocarbons in the Ocean .. 225
14.1.2 Concentrations of Monocyclic Aromatic Hydrocarbons
in Seawater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
228

14.2 Monocyclic Aromatic Hydrocarbons in Marine Sediments . . . . . . . . . . .

231

14.3 Degradation of Monocyclic Aromatic Hydrocarbons in
Water and Sediments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

232

14.4 Bioaccumulation of Monocyclic Aromatic Hydrocarbons
by Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

233

14.5

Concentrations of Monocyclic Aromatic Hydrocarbons
in Tissues of Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

235

14.6 Toxicity of Monocyclic Aromatic Hydrocarbons to Marine Organisms .. 237
14.7 Environmental Effects of Monocyclic Aromatic Hydrocarbons
in Produced Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHAPTER 15: POLYCYCLIC AROMATIC HYDROCARBONS
IN THE OCEAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.1

239

241

Sources of Polycyclic Aromatic Hydrocarbons in the Marine Environment . 241
15.1.1 Formation of Polycyclic Aromatic Hydrocarbons . . . . . . . . . . . .
241
15.1.2 Petrogenic Polycyclic Aromatic Hydrocarbons . . . . . . . . . . . . . .
243
15.1.3 Pyrogenic Polycyclic Aromatic Hydrocarbons . . . . . . . . . . . . . .
247

Contents

15.2 Polycyclic Aromatic Hydrocarbons in Seawater . . . . . . . . . . . . . . . . . . .

ix
254

15.3 Polycyclic Aromatic Hydrocarbons in Marine Sediments . . . . . . . . . . . .
262
15.3.1 Sorption of Polycyclic Aromatic Hydrocarbons to Sediments . . . 262
15.3.2 Concentration of Polycyclic Aromatic Hydrocarbons in Sediments 266
15.4 Degradation of Polycyclic Aromatic Hydrocarbons . . . . . . . . . . . . . . . .
15.4.1 Photooxidation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.4.2 Microbial Degradation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5 Bioaccumulation of Polycyclic Aromatic Hydrocarbons by
Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5.1 Uptake of Polycyclic Aromatic Hydrocarbons by
Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5.2 Metabolism of Polycyclic Aromatic Hydrocarbons
by Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.5.3 Net Bioaccumulation and Trophic Transfer of Polycylic
Aromatic Hydrocarbons by Marine Organisms . . . . . . . . . . . . . .

269
269
271
277
277

281
288

15.6 Concentrations of Polycyclic Aromatic Hydrocarbons in Tissues
of Marine Organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

293

15.7 Toxicity of Polycyclic Aromatic Hydrocarbons to Marine O r g a n i s m s . . .
15.7.1 Toxicity of Unmodified PAHs . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7.2 Phototoxicity of PAHs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15.7.3 Causes of Toxicity of Complex Mixtures Containing PAHs . . . .
15.7.4 Mutagenicity and Carcinogenicity of PAHs . . . . . . . . . . . . . . . .
15.7.5 Human Toxicity of PAHs in Seafoods . . . . . . . . . . . . . . . . . . . .

299
299
304
308
310
311

15.8 Environmental Effects of Polycyclic Aromatic Hydrocarbons
in Produced Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

313

REFERENCES

..................................................

INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

319
439


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Preface

Large amounts of organic and inorganic chemicals enter estuarine and coastal marine
environments from natural and anthropogenic sources. Human activities have increased
the flux of many naturally occurring chemicals, such as metals, naturally occurring
radioactive materials (NORM), and petroleum hydrocarbons, to the ocean. On the other
hand, many industrial, domestic, and agricultural activities are the sole sources of an
ever-increasing number of synthetic organic chemicals in the ocean.
Some of these chemicals enter the marine environment in forms and concentrations
that may be harmful to marine organisms and ecosystems, or to consumers, including
humans, of foods from the sea. A chemical must be in a bioavailable form in order to
produce toxic responses in marine organisms or their consumers. A chemical is bioavailable if it is in a form that can move through or bind to the surface coating (e.g., skin, gill
epithelium, gut epithelium, cell membrane) of an organism and thereby elicit biological
responses. Bioavailable chemicals may accumulate to high, potentially toxic concentrations in the tissues of marine organisms or their consumers if they have a higher affinity
for some tissue compartment (e.g., lipids) than for the ambient water, or if they bind to
tissue components.
Naturally occurring, bioavailable chemicals are bioaccumulated by marine organisms, often to concentrations much higher than those in the ambient seawater. Concentrations of these chemicals in tissues of marine organisms often are in equilibrium
with the natural concentrations in seawater. Thus, the tissues of marine organisms contain natural background concentrations of many naturally-occurring chemicals, such as
most metals and metalloids. These background body burdens of chemicals probably are
not toxic to the marine organisms. However, increased inputs to the marine environment

of some of these chemicals from man's activities can result in increases in the concentrations of the chemicals in seawater and enhanced bioaccumulation in the tissues of
marine organisms, possibly to concentrations that are toxic to the organisms themselves
or their consumers, including man.

xi


xii Bioaccumulation in Marine Organisms
Several solid and liquid wastes are generated during the exploration, development,
and production phases of oil and gas activities in coastal and offshore marine waters.
Some of these wastes are discharged intentionally to the ocean. In U.S. territorial waters,
discharges to the ocean from offshore oil rigs and platforms are regulated by National
Pollution Elimination System (NPDES) permits that are issued by the U.S.
Environmental Protection Agency (EPA) or a state environmental protection agency designated by EPA. NPDES permit limitations and requirements are intended to protect the
local receiving water environment and its uses from harm attributable to the permitted
discharges.
Effluent standards for produced water destined for ocean disposal focus primarily on
limiting the concentration of petroleum (usually measured as total oil and grease) in the
treated effluent. The oil and gas industry treats produced water through a treatment system designed to remove oil and grease from the wastewater stream to concentrations
below the NPDES limits. The Final NPDES General Permit for the westem portion of
the outer continental shelf of the Gulf of Mexico (GMG290000) states that produced
water discharges must contain less than a daily maximum of 42 mg/L and a monthly
average of 29 mg/L total oil and grease (57 FR 224:54642, November 19, 1992 and 58
FR 231:63964, December 3, 1993). Modem produced water treatment systems are capable of generating an effluent that meets these requirements.
Monitoring requirements in the Gulf of Mexico General Permit include periodic
measurements of produced water discharge rates, toxicity of the effluent to marine
organisms, level of radioactivity from 226radium and 228radium in the effluent, and bioaccumulation of selected contaminants in marine animals in the receiving water environment. Flow and radium radioactivity are reported to EPA in the periodic Discharge
Monitoring Report (DMR). The no observed toxic effects concentration of the effluent,
as determined with a 7-day rapid chronic toxicity test, must be equal to or greater than
the critical dilution concentration determined according to a mathematical formula in the

permit.
The original permit required that a site-specific bioaccumulation monitoring study be
performed at all existing facilities that discharge more than 4,600 barrels/day (731,000
liters/day) of treated produced water to the ocean. The permit was subsequently modified to enable operators to participate in an EPA-approved, industry-wide bioaccumulation monitoring study. Twice each year, three species of marine animals, a crustacean,
mollusk, and nektonic fish, were collected within 100 m down-current from the produced water discharge (Offshore Operators Committee, 1997a,b). Their edible tissues
were analyzed for three metals (arsenic, cadmium, and mercury), three monocyclic aromatic hydrocarbons (benzene, toluene, and ethylbenzene), two polycyclic aromatic
hydrocarbons (fluorene and benzo[a]pyrene), bis(2-ethylhexyl)phthalate, phenol, and
the naturally-occurring radium isotopes, 226Ra and 228Ra.
A part of the monitoring study was a review of the scientific literature on bioaccumulation of the metals and organic chemicals of concern to EPA by marine organisms
(Neff, 1997a). That review has been updated and expanded as this book. The objective
of this book is to critically summarize and interpret the scientific literature dealing with
the bioaccumulation and ecotoxicology of metals, NORM, and selected organic chemicals by marine organisms and their consumers, with particular emphasis on chemicals
commonly found in treated produced water from oil and gas wells. The book also
includes a summary of the range of concentrations of selected metals, NORM, and


Preface xiii
organic chemicals in the tissues of marine organisms from estuarine and marine waters
of the world. These summaries are based on data tables compiled by Neff (1997a). The
summary tables of tissue residues of selected metals and organic compounds in tissues
of marine organisms are not reproduced in this book but are available upon request at

This book is in three parts. The first part deals with the sources, volumes, composition, and fates in the marine environment of produced water. Emphasis is placed on a
summary of the available information on the chemical composition of produced waters
from wells world-wide. The second part of the review is a summary of our current understanding of the process of bioaccumulation of chemicals by freshwater and marine
organisms. The final section of the book is a discussion of the environmental fates and
biological effects of potentially toxic chemicals that have been identified at elevated
(significantly higher than concentrations in ambient seawater) concentrations in produced water from different sources.
The second part of this book begins with a brief discussion of the mechanisms of
bioaccumulation and food chain transfer of metal and organic contaminants in the

marine environment. The focus of this evaluation is on the bioaccumulation and food
chain transfer in the marine environment of the metals and organic chemicals of environmental concern in produced water. The published scientific literature on the concentrations of several of these chemicals in the tissues of marine organisms from throughout
the world is summarized. A discussion is included in the third part of the book on the
physical/chemical behavior in the ocean and toxicity to marine organisms of each chemical evaluated. Integration of information about the physical/chemical behavior, bioaccumulation, and toxicity of each compound of concern allows conclusions to be made
about its potential to cause harm (its ecological risk) to marine organisms and ecosystems, and human consumers of fishery products, at the concentrations commonly found
in marine environments. Finally, an evaluation is made of the importance of produced
water as a source of chemical residues in the tissues of marine animals living near offshore oil and gas platforms.
The current scientific literature on the various topics covered in this book was
accessed through detailed, computerized literature searches. The focus of the literature
searches was on the most recent publications on the topics of interest. Many chemical
analyses of concentrations of metals and organic chemicals in marine environmental
matrices (seawater, sediments, tissues of marine organisms) performed before about
1980 were inaccurate or insensitive because of inadequate analytical methods and frequent lack of consideration of problems of laboratory contamination and matrix interferences from the salts in produced water and seawater. Therefore, the most recent
available analytical data were used whenever possible.
JERRY M. NEFF
Battelle
November 2001


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Acknowledgements

Preparation of this literature review was supported through contracts from the Gulf of
Mexico Offshore Operators Committee to Continental Shelf Associates, Inc. and to
Battelle. Battelle also provided financial and clerical support for completion of this book.
I wish to express my appreciation to the members of the Bioaccumulation Working
Group of the Offshore Operators Committee for their helpful review and suggestions
during the preparation of this report. I would particularly like to thank Working Group

members, Dr. James P. Ray, Dr. Robert C. Ayers, Dr. Stanley Cutrice, Dr. Andrew
Glickman, Dr. Bela M. James, Dr. Lawrence A Reitsema, Dr. Joseph P. Smith, and
Dr. James E. O'Reilly, for their critical technical reviews of the manuscript and their
many helpful suggestions for improving its quality.

KV


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CHAPTER 1

Produced Water

1.1 COMPOSITION OF PRODUCED WATER
1.1.1. Sources and Treatment of Produced Water

During millions of years of geologic time, petroleum and natural gas may accumulate
in porous sediments (e.g., sands) trapped between layers of impermeable rock deep
within the earth (Collins, 1975). Water may be trapped during millions of years with the
oil and gas. This water may be derived from ancient fresh or seawater (connate water)
and often is as old as the fossil fuels in the reservoir. When the hydrocarbon reservoir is
tapped by a well, the produced fluids may contain water. Also, in some oil fields, fresh
or seawater may be injected into the reservoir through injection wells to displace oil into
the production wells. Sometimes, this injection water channels through to the production
well and is produced with the oil and gas. The water produced with oil and gas is called
produced water, formation water, or oilfield brine (Neff et al., 1987; Black et al., 1994;
Patin, 1999).
Before the crude oil can be refined or the gas processed, the water must be removed.

During offshore operations, separation of the produced water from the oil and gas may
take place on the production platform or the oil/gas/water mixture may be sent through
a pipeline to a shore facility where the produced water is separated from the oil and gas.
If not re-injected into another well, the produced water is treated to meet local regulatory limits for oil and grease before it is discharged to the ocean from the platform or
from an ocean outfall from a shore-based treatment facility.
In most of the world, national or regional regulatory agencies have set limits on the
concentration of petroleum hydrocarbons (or total oil and grease) that can remain in produced water destined for ocean disposal. The current limit for total oil and grease (dispersed and dissolved oil, measured by gravimetric or infrared analysis) in treated
produced water destined for ocean disposal in U.S. Federal waters and state waters of
Upper Cook Inlet, AK, is 42 mg/L (ppm) daily maximum and 29 mg/L monthly average
(Otto and Arnold, 1996; Veil, 1997). Discharge of produced water to coastal estuarine


2

Bioaccumulation in Marine Organisms

and marine waters is no longer permitted in the United States. The permit limits for
treated produced water discharges offshore in Australia are 30 mg/L daily average and
50 mg/L instantaneous maximum (Black et al., 1994). The regulatory limit for total oil
and grease in produced waters discharged to most offshore waters of the North Sea, the
Mediterranean Sea, the Arabian Gulf, and Asia is 40 mg/L (Ray, 1996).
The oil/gas/water mixture may be processed through separation devices to separate
the three phases from one another. The types of equipment used on platforms in the western Gulf of Mexico to remove oil and grease from produced water include, in order of
frequency of use, mechanical and hydraulic gas floatation units, skimmers, coalescers,
hydrocyclones, and filters (Otto and Arnold, 1996). Hydrocyclones, because of their
operating efficiency and limited space requirements, are being used with increasing frequency for oil/water separation on offshore platforms in the Gulf of Mexico, North Sea,
Australia, the Middle East, and Southeast Asia (Cornitius, 1988). Chemicals may be
added to the process stream to improve the efficiency of oil/gas/water separation. Even
with the most advanced separation equipment, the oil/water separation is not 100 percent
efficient. Treated produced water that is discharged to the ocean often contains small

amounts of hydrocarbons, other organic chemicals, dissolved salts, and metals.
Small amounts of specialty chemicals may be added to the production stream at different steps in the production and treatment process to prevent corrosion, foaming, scale
formation, hydrogen sulfide formation, and bacterial growth, or to improve the efficiency
and completeness of oil/water separation (Hudgins, 1989, 1991, 1992). Most of these
chemicals remain in the oil or gas phases; others are water soluble, remain in the
produced water, and are discharged with it to the ocean. Approximately 19 percent of the
offshore production chemicals used on platforms in the North Sea are discharged to the
ocean in treated produced water, including more than 50 percent of the emulsifiers, surfactants, oil removing agents, and scale inhibitors (van Hattum et al., 1992; Ynnesdal and
Furuholt, 1994; Hudgins, 1994). Only small amounts (less than 20 percent of the
amounts used) of corrosion inhibitors, oxygen scavengers, emulsion breakers,
defoamers, and gas treatment agents are discharged with produced water to the ocean.

1.1.2 Naturally-Occurring Chemicals in Produced Water
Produced water contains a variety of chemicals that have been dissolved from the
geologic formations in which the produced water resided for millions of years (Table 1).
These chemicals include inorganic salts (essentially the same salts that are found in seawater and make the ocean salty), several metals and metalloids, and a wide variety of
organic chemicals. It should be noted that the concentrations in Table 1 are the extreme
ranges for all reported concentrations in produced water. Many of the high values, particularly for metals, may be anomalous, caused by matrix interferences from the high
concentrations of dissolved salts in most produced waters (Neff, 1987). The highest values are extremely rare and concentrations of most constituents in most produced waters
fall in the lower part of the ranges listed in Table 1.

Salinity and Inorganic ions. The salt concentration (salinity) of produced water may
range from a few parts per thousand (%o) to that of a saturated brine (about 300%o)
(Rittenhouse et al., 1969; Large, 1990). Some produced waters have so little salt that
they are drinkable. However, most produced waters from offshore sources have salinities
greater than that of seawater (about 35%o) (Collins, 1975). Most produced waters from


Chapter 1 - P r o d u c e d Water

3

Table 1.
Concentration ranges of several classes of naturally-occurring metals and organic chemicals in
produced water world-wide. Concentrations are mg/L (parts per million).
Chemical

Class

Concentration

Range*

Total organic carbon
_<0.1 - > 1 1 , 0 0 0
Total saturated hydrocarbons
17-30
Total benzene, toluene, ethylbenzene, and xylenes (BTEX)
0.068- 578
Total polycyclic aromatic hydrocarbons (PAHs)
0.04- 3.0
Total steranes/triterpanes
0.14-0.175
Total phenols
0.6-23
Total organic acids
<0.001 - 1 0 , 0 0 0
Sulfate
<1.0-8,000
Arsenic

0.000004 - 0.32
Barium
<0.001 - 2,000
Cadmium
0.0000005 - 0.49
Chromium
<0.000001 - 0.39
Copper
<0.000001 - 5 5
Iron
<0.0001 - 465
Lead
<0.000001
- 18
Manganese
0.0002 - 7.0
Mercury
<0.000001 - 0.075
Nickel
<0.000001
- 1.67
Zinc
0.000005 - 200
Total radium (pCi/L)
0 - 5,150
*Data from Kharaka et al. (1978, 1995), Armstrong et al. (1979), Brooks et al. (1980),
Middleditch (1981, 1984), Sauer (1981 b), Lysyj (1982), Kramer and Reid (1984), Hanor
and Workman (1986), Fisher (1987), Grahl-Nielson (1987), O'Day and Tomson (1987),
McGowan and Surdam (1988), Boesch et al. (1989a,b), Macpherson (1989), Means et al.
(1989, 1990), Neff et al. (1989c), Brown et al. (1990), Louisiana Dept. of Environmental

Quality (1990), Barth (1991 ), Rabalais et al. ( 1991 ), Stephenson and Supernaw (1990),
Stueber and Walter (1991), Hamilton et al. (1992), Jacobs et al. (1992), Tibbetts et al.
(1992), Stephenson (1992), van Hattum et al. (1992), Yerrens and Tait (1993),
Stephenson et al. (1994), Bakke et al. (1996), Trefry et al. (1996).

Louisiana coastal waters of the Gulf of Mexico have salinities between 50%0 and 150%0
(Hanor et al., 1986; Louisiana DEQ, 1990). Produced waters from production facilities
in the Central Valley of Califomia, the North Slope of Alaska, coastal Texas, and central
Mississippi, U.S.A., have salinities of 18%o to 320%o (Kharaka et al., 1995).
As in seawater, the salinity of produced water is due primarily to dissolved sodium
and chloride, with smaller contributions of calcium, magnesium, and potassium (Table
2). However, quite frequently, the ion ratios in produced water are different from those
in modem seawater. For example, the ratios of calcium to magnesium in two Indonesian
produced waters are 6.3 and 23.5, compared to a Ca/Mg ratio in oceanic seawater of 0.31
(Neff and Foster, 1997). The Ca/Mg ratios in three produced waters from platforms in
the southem Caspian Sea range from 8.91 to 9.71 (Samedova et al., 1997).
The concentration of sulfate in produced water is highly variable. Most produced
waters contain lower concentrations of sulfate than natural seawater does. A high sulfate


4

Bioaccumulation in Marine Organisms

Table 2.
Salinity (%0) and concentrations (mg/L) of selected inorganic ions in typical seawater and in
produced water.
Chemical

Seawater*

World Produced Water*

Salinity (%o)
32 - 36
3 - 320
Sodium
10,560
65 - 97,000
Chloride
18,900
<5 - 201,000
Calcium
400
13 - 118,800
Strontium
13
7 - 3,200
Magnesium
1,270
4 - 11,700
Potassium
380
3 - 6,500
Sulfate
880
<1 - 1,650
Sulfide
--0.12 - 256
Ammonia

--<0.1 - 650
*Data from Collins (1975), Large and Tibbetts (1990), and Van Hattum et al. (1992),
Barth (1991), Kharaka et al. (1995), and Witter and Jones (1999).

concentration in a produced water sample may indicate that saline water injected into the
formation to enhance petroleum production has broken through and is appearing in the
produced water (Large and Tibbetts, 1990). The sulfate concentration in produced water
is important because it controls the solubility and, thereby, the concentration of several
other elements, particularly calcium and barium, in solution in the produced water.
Produced water in the geologic formation is in the reduced state. Therefore, some of the
sulfur may be present as elemental sulfur or sulfide. Produced water from a crude oil processing facility in California, U.S.A., contains 48 to 256 mg/L sulfides and 0.6 to 42
mg/L elemental sulfur (WiRer and Jones, 1999).
Sulfides, usually as hydrogen sulfide and polysulfides, may be formed by bacterial
reduction of sulfate in anoxic produced water (Large, 1990). They are most abundant in
water produced with sour gas or crude oils containing high concentrations of sulfur
(WiRer and Jones, 1999). Sulfides are highly corrosive and their generation in the
production stream usually is controlled by use of biocides. Hydrogen sulfide may also
be formed during storage of produced water samples for later analysis or use in toxicity
tests. Hydrogen sulfide, because of its high toxicity, may confound the results of toxicity tests. Hydrogen sulfide concentrations as high as 1,000 mg/L have been detected in
produced water (Kochelek and Stone, 1989).
Ammonia is not frequently analyzed in produced water, but when it is, concentrations
are highly variable. Many produced waters do not contain detectable concentrations of
ammonia. Among those that do, concentrations may be as high as 650 mg/L (Table 2).
Some produced waters from production platforms in the Santa Barbara Channel,
California, USA, contain up to 420 mg/L ammonia (Neff, 1997c). Ammonia may be
formed by bacterial degradation of organo-nitrogen compounds in the formation or during storage of produced water. Because it is highly toxic to marine organisms, it may,
like sulfide, affect the results of produced water toxicity tests performed in the laboratory. It is uncertain, because of their volatility and high aqueous solubility (favoring rapid
dilution), if ammonia and sulfide actually contribute to the toxicity to marine organisms
in the receiving water environment of produced water discharged to the ocean. By way

C h a p t e r 1 - P r o d u c e d Water

5

of comparison, the four largest municipal wastewater plants in the Los Angeles area discharge more than 4 x 1012 liters/day of wastewater containing 23 to 35 mg/L ammonia
to the southern California Bight (Raco-Rands, 1996). The volume of produced water discharged to the Santa Barbara Channel is about 1.6 x 107 liters/day (Table 14).
Metals. Produced water may contain several metals in solution. The metals present
and their concentrations in produced waters from different sources are extremely variable, depending on the age and geology of the formations from which the oil and gas are
produced (Collins, 1975). There is not a good correlation between concentrations of metals in crude oil and the water produced with it (Olsen et al., 1995; Samedova et al.,
1997). Some metals, such as vanadium and nickel, may be very abundant in crude oils
but rare in produced water. These metals are present as metal-organic complexes (porphyrins) in the oil and do not partition into the produced water phase in contact with the
oil. However, some North Sea produced waters contain high concentrations of nickel
(Table 3), possibly derived from biodegradation of nickel porphyrins. Several metals,
including cadmium, lead, and zinc, dissolve into crude oil and produced water as they
migrate through mineral ore deposits containing these metals (Olsen et al., 1995;
Samedova et al., 1999). Mercury from cinnabar deposits or complexed with the solid
organic phase in the hydrocarbon reservoir may "evaporate" into natural gas in the formation and condense out of the gas into the produced water when the gas and water are
brought to surface temperature and pressure (Battelle, 1994).
Because produced water is thought to be a concentrate of ancient seawater or fresh
water, it is not surprising that the metals present in seawater also are present in produced
water. However, a few metals may be present in produced waters from different sources
at concentrations substantially higher (1,000-fold or more) than their concentrations in

Table 3.
Concentration ranges of several metals in produced water from seven platforms in the northwestern Gulf of Mexico and 12 discharges to the Norwegian Sector of the North Sea. Typical
concentrations in seawater are included for comparison. Concentrations are/~g/L (ppb).
Metal

Seawater

Gulf of Mexico
Produced Water

North Sea
Produced Water

Arsenic (As)
1- 3
0.5 - 31
0 . 9 6 - 1.0
Barium (Ba)
3 - 34
81,000- 342,000
107,000- 228,000
Cadmium (Cd)
0.001 - 0.1
<0.05 - 1.0
0.45 - 1.0
Chromium (Cr)
0.1 - 0.55
<0.1 - 1.4
5 - 34
Copper (Cu)
0.03 - 0.35
<0.2
12 - 60
Iron (Fe)
0.008 - 2.0
10,000 - 37,000

4,200 - 11,300
Lead (Pb)
0.001 - 0.1
<0.1 - 28
0.4 - 10.2
Manganese (Mn)
0.03 - 1.0
1,000- 7,000
NA
Mercury (Hg)
0.00007 - 0.006
<0.01 - 0.2
0.017 - 2.74
Molybdenum (Mo)
8 - 13
0.3 - 2.2
NA
Nickel (Ni)
0.1 - 1.0
< 1 . 0 - 7.0
2 2 - 176
Vanadium (V)
1.9
<1.2
NA
Zinc (Zn)
0.006- 0.12
1 0 - 3,600
1 0 - 340
From Dept. of Energy (1997a), Offshore Operators Committee (1997), Roe Utvik (1999),

and A.G. Melbye, Sintef, Norway (personal communication, 1999).


6

Bioaccumulation in Marine Organisms

clean natural seawater. The metals most frequently present in produced water at elevated
concentrations include barium, cadmium, chromium, copper, iron, lead, nickel, and zinc
(Neff et al., 1987) (Table 1). Usually only a few of these metals are present at elevated
concentrations in a particular produced water sample. For example, Neff et al. (1989c,
1992) reported that only barium, lead, and zinc are present at elevated concentrations in
produced water from 2 platforms off Louisiana, U.S.A.
If water flooding with seawater is used to enhance hydrocarbon production, the metal
concentrations in produced water often change gradually over time to more closely
resemble the metal concentrations in modem seawater (Stephenson et al., 1994). For
most metals this is a decrease in concentration. Some chemicals such as barium and
radium may precipitate with sulfate if seawater (high in sulfate) is used for water-flooding. Therefore, although the volume of produced water usually increases with the age of
the well, total mass loadings of metals discharged in produced water may not increase;
mass loadings of some metals may actually decrease.
The highest concentrations of arsenic and barium have been recorded for Gulf of
Mexico produced waters, probably because these elements usually are not analyzed in
produced water from other sources. Barium may be present at high concentrations in
produced waters that contain very low concentrations of sulfate (Neff and Sauer, 1995).
Water-flooding with seawater may increase the concentration of sulfate (present in seawater at a concentration of about 900 mg/L) in the formation water, causing barium precipitation as barite, lowering the concentration of barium in the produced water
(Stephenson et al., 1994). In the absence of sulfate, barium is soluble in hot, geopressured, high ionic strength connate water in the hydrocarbon-beating formation.
However, some of the barium may be present as minute particles of barite (Olsen et al.,
1995). Arsenic concentrations usually are low, but some produced waters contain elevated concentrations. Produced water from the Funan platform in the Gulf of Thailand
contains more than 380/~g~ arsenic, more than 65 percent of which is in solution
(Frankiewicz et al., 1998). The concentrations of barium, arsenic, and other elements in

produced water probably are in equilibrium with elements in the feldspars, plagioclase,
biotite, and sandstones in the formation (Bloch and Key, 1981; Macpherson, 1989).
Produced water from seven platforms in the northwest Gulf of Mexico, analyzed by
modem analytical methods, contain elevated concentrations of barium, iron, manganese,
lead, and zinc, and in a few cases arsenic (Table 3). Several samples of produced water
from the Norwegian Sector of the North Sea contain elevated concentrations of mercury
and nickel. Produced water from natural gas platforms in the Gulf of Thailand often contains elevated concentrations of mercury (1.4 to 235 ~g/L) (Battelle, 1994; Frankiewicz
et al., 1998). The mercury is from coal and carbonaceous shales in or near the producing reservoirs and is produced as elemental mercury vapor with the natural gas. Most of
the mercury in the produced water is in particulate forms. Unocal Thailand has developed a produced water cleaning process that cleans the produced water to meet proposed
environmental standards of <40 mg/L total petroleum hydrocarbons, <10 ktg/L mercury,
and <250/~g/L arsenic. Generally, produced water from gas wells contains more mercury and probably arsenic than produced water from oil wells.
Nearly all the iron in produced water is particulate and probably is metallic iron or
precipitated iron oxide. Naturally biodegraded crude oils often contain a high concentration of iron, which may be derived in part from microbial corrosion of steel in the production tubing and production tank (Olsen et al., 1995). Formation water is anoxic and


Chapter 1 - Produced Water

7

some iron may be present at high concentration in solution. However, when the formation water is brought to the surface and is exposed to the atmosphere, the iron precipitates as iron oxides. Manganese behaves like iron; it is soluble in anoxic water but
precipitates as various oxyhydroxides in the presence of oxygen.. Several other metals
in produced water co-precipitate with iron and manganese oxides. Zinc and possibly lead
could be derived in part from galvanized steel structures in contact with the produced
water or with other waste streams that may be treated in the oil/water separator system.
The Gulf of Mexico produced waters analyzed recently by advanced methods contain
<0.05 to 1.0/tg/L cadmium, similar to concentrations in North Sea produced water
(Table 3). Chromium, copper, molybdenum, nickel, and vanadium concentrations
usually are low relative to expected concentrations in the environment. Some North Sea
produced waters contain copper at a concentration about 200 times higher than the concentration in seawater.
Radioisotopes. Several naturally occurring radioactive materials (NORM) occur in

produced water. The most abundant usually are radium-226 and radium-228 (226Ra and
228Ra). The radium is derived from the radioactive decay of uranium and thorium associated with certain rocks and clays in the hydrocarbon reservoir (Reid, 1983; Kraemer
and Reid, 1984; Michel, 1990). 226Ra (half-life 1,601 years) is an a-emitting daughter of
uranium-238 and uranium-234; 228Ra (half-life 5.7 years) is a r-emitting daughter of
thorium-232. Although the two radium isotopes are from different sources in the geologic formation, their concentrations in produced water tend to covary (Fisher, 1995).
Concentrations of both 226Ra and 228Ra increase with salinity in oil and gas well produced waters from coastal and offshore waters of Louisiana, U.S.A. However, the correlation between the salinity and concentrations of 226Ra, 228Ra, and total radium in
produced water from some formations is not good; many produced waters of all salinities contain little or no radium and some low-salinity produced waters contain significant amounts of radium.
Produced water from 153 oil and gas wells in Texas, U.S.A., contains 0.1 picocurie/L
(pCi/L) to 5,150 pCi/L 226Ra, and possibly a similar activity of 228Ra (Fisher, 1995).
(1 pCi = 0.037 bequerels [Bq]; 1 Bq = 1 disintegration/sec). A picocurie of 226Ra is
equivalent to 1 picogram (pg) of radium; a pCi of 228Ra is equivalent to 0.0037 pg of
radium (Santschi and Honeyman, 1989). Concentrations of 226Ra and 228Ra in produced
water from platforms along the Louisiana, U.S.A., coast range from below the detection
limit to 1,565 pCi/L and 1,509 pCi/L, respectively (Table 4), equivalent to 1.56 ng/L
(parts per trillion) and 0.006 ng/L radium, respectively (Kraemer and Reid, 1984; Neff
et al., 1989c). Total radium activities in these produced waters range from less than
0.2 pCi/L to more than 5,000 pCi/L. Average concentrations of radium isotopes in produced water from oil and gas wells elsewhere in the world usually are lower than those
for produced water from the U.S. Gulf of Mexico region (Table 4). By comparison, the
concentration of 226Ra and 228Ra in surface waters of the ocean are 0.027 to 0.040 pCi/L
and about 0.005 pCi/L, respectively (Santschi and Honeyman, 1989; Nozaki, 1991).
Several other radionuclides have been identified in the NORM of produced water,
including 89Sr, 9~ 212Bi, 214Bi, 228Ac, 21~ 212pb, and 214pb (van Hattum et al., 1992).
Activities of these radionuclides are much lower than those of radium. For example, offshore produced waters from the U.S. Gulf of Mexico containing 91 to 1,494 pCi/L of
226Ra also contain 5.2 to 16.7 pCi/L of 21~ (Hart et al., 1995).


8

Bioaccumulation in Marine Organisms

Total Organic Carbon. The concentration of total organic carbon (TOC) in produced
water ranges from less than 0.1 to as high as 11,000 mg/L (ppm) (Fisher, 1987) and is
highly variable from one location to another (Tables 1 and 5). Concentrations of TOC in
produced water from the North Sea usually are in the range of 14 to more than 1,000 ppm
(Tibbetts et al., 1992; Stephenson et al., 1994); produced water from the Bass Strait,
Australia, contains 15 to 313 ppm TOC (Brand et al., 1989). Produced water from production wells in the U.S. Gulf of Mexico contain 68 to 540 ppm TOC (Neff, 1997).
Most of this organic matter in treated produced water is in solution or colloidal suspension (Means et al., 1989). Therefore, dissolved organic carbon (DOC) concentration
is almost equivalent to TOC concentration. Concentrations of DOC vary widely from
less than 17 to more than 11,000 mg/L in produced water from different formations and
even in produced water from within a particular basin (Fisher, 1987). Highest DOC concentrations are in produced waters from Pliocene formations. Much of the DOC in the
144 samples of produced water analyzed by Fisher (1987) can be accounted for by
volatile C 2 through C 5 organic acid anions
Organic Acids. As shown in Table 5, much of the TOC in produced water consists of
a mixture of low molecular weight carboxylic acids (fatty acids), such as acetic acid, propionic acid, butyric acid, and valeric acid (Somerville et al., 1987; Means and Hubbard,
1987; Barth, 1991). Volatile organic acids represent 60 to 98 percent of the total
extractable organic matter in produced water from three production facilities in the North
Sea (Table 6). Most of the remainder of the organic matter in the produced waters is
hydrocarbons and phenols. Traces of higher molecular weight C 8- through C17-fatty
acids also are present.
Most of the organic acids in produced water are short-chain aliphatic monocarboxylic
acids (Table 7). The most abundant acid usually is acetic acid, and abundance decreases
with increasing molecular weight; however, in some coal-associated waters, propionic
acid may be most abundant (Fisher, 1987). Dicarboxylic acids may be present at concentrations usually lower than 100 mg/L; succinic acid and methylsuccinic acid often are
most abundant (Lundegard and Kharaka, 1994). Linear and branched C 5- through C 7fatty acids are present at concentrations of 0.01 to 2 mg/L each in several produced

Table 4.
Mean or range of activities of 226Ra and 228Ra in produced water from different locations.
Activities are pCi/L.

Location

Texas
Louisiana Gulf Coast
Offshore U.S. Gulf of Mexico
Santa Barbara Channel, CA
Cook Inlet, AK
North Sea
S. Java Sea, Indonesia
Ocean water (background)

Radium-226
0.1 - 5,150
N D - 1,565
91.2 - 1,494
165
<0.4 - 9.7
44.8
7.6 - 56.5
0.027 - 0.04

NA not analyzed. ND not detected.

Radium-228
NA
N D - 1,509
162 - 600
137
NA
105
0.6 - 17.7
0.005

Reference
Fisher, 1995
Kraemer & Reid, 1984
Hart et al., 1995
Neff, 1997c
Neff, 1991a
Stephenson et al., 1994
Neff & Foster, 1997
Santschi & Honeyman,
1989