x>EPA
United States
Environmental Protection
Agency
Environmental Research
Laboratory
Gulf Breeze FL 32561
EPA-600/9-78-038
December 1978
Research and Development
First
American-Soviet
Symposium on
Chemical
Pollution of the
Marine Environment
-------
-------
EPA-600/9-78-038
December 1978
FIRST AMERICAN-SOVIET SYMPOSIUM ON
CHEMICAL POLLUTION OF THE MARINE ENVIRONMENT
Odessa, USSR
May 24 to 28, 1977
Symposium 'Sponsored as Part of the U.S.-U.S.S.R.
Agreement on Protection of the Environment
Compiled by
Karl K. Turekian
Chairman, U.S. Delegation
and
Anatoliy I. Simonov
U.S.S.R. Leader, Project VI-2.1
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
GULF BREEZE, FLORIDA 32561
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DISCLAIMER
This report has been reviewed by the Gulf Breeze Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
11
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FOREWORD
The Joint American-Soviet Committee on Cooperation in the Field of
Environmental Protection, established by an agreement signed May 23, 1972,
in Moscow, identified 11 ecological problem areas for cooperative investiga-
tion and exchange of information. In accordance with these objectives, the
First American-Soviet Symposium on Chemical Pollution of the Marine Environ-
ment was convened May 24-28, 1977, in Odessa, U.S.S.R., for a joint examination
of the accumulation and spread of chemical pollution in international oceanic
waters.
In this publication, the proceedings are arranged in the order of their
presentation. Discussions engendered by papers presented in English and
Russian reflected interest of participants in reconvening a Second U.S.-
U.S.S.R. Symposium on Chemical Pollution in the U.S. within two or three
years. Suggested topics for the subsequent session were: transformation and
fate of chemical pollutants in the marine environment; influence of pollution
on physical and chemical professes; and methods for determining pollution in
the marine environment.
Success of the symposium resulted from the combined efforts of planners,
travel coordinators, speakers, and translators. Publication of the proceed-
ings by the Environmental Research Laboratory, U. S. Environmental Protection
Agency (EPA), Gulf Breeze, Florida, fulfills the protocol agreement for
Project VI-2.1 requiring simultaneous and independent publication in both
countries after coordination of manuscripts.
Thomas W. Duke
Director
Environmental Research Laboratory
Gulf Breeze, Florida
U. S. Leader of Project VI-2.1
111
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ABSTRACT
The First American-Soviet Symposium on Chemical Pollution of the Marine
Environment examines the impact of chemical pollutants on the world's oceans
and estuaries. Subjects of the papers presented by American and Soviet
specialists include: fate of heavy metals in estuaries and the Gulf of Mexico;
transport of natural radionuclides in shelf waters of the eastern U.S.; the
distribution and dynamics of trace metals in pore water and sediments; bio-
geochemical research on metals in the world's oceans; monitoring chemical
pollution and forecasting its biological consequences; arsenic, antimony, and
mercury in seawater; pollution of the Caribbean Basin; oil and oil products in
surface waters of the Atlantic, Pacific, and Indian Oceans; the forms of heavy
metals in seawater (e.g. mercury); methods of sampling water from the ocean
surface microlayer and the technical composition of the microlayer; a method
for determining mercury; scientific aspects of marine pollution problems; and
the management of the quality of the marine environment. Publication of the
proceedings held May 24-28, 1977f in Odessa, U.S.S.R., is in compliance with
the Memorandum from the 4th Session of the Joint U.S.-U.S.S.R. Committee on
Cooperation in the Field of Environmental Research.
iv
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CONTENTS
Foreword iii
Abstract iv
Introduction 1
Protocol 3
Participants in the Symposium 5
Biological Investigations of Metals in the World's Oceans in
Connection with Monitoring of the Chemical Pollution of the
Marine Environment, N. P. Morozov, S. A. Patin, and C. A.
Petukhov '. 8
Effect on the Diagenetic Status of Sediments on Trace Metal in
Pore Waters, Michael L. Bender ........ 18
The Fate of Metals in Estuaries, Karl K. Turekian .......... 27
The Structure of Arsenic and Stibium Fields in the Caribbean Sea,
A, I. Ryabinin and A. S. Romanov 39
Chemical Forms of Mercury in Marine Waters, A. K. Prokof'yev. .... 47
The Fate of Heavy Metals Added to the Gulf of Mexico by the Miss-
issippi River, B. J. Presley 6]_
Oil Products in Surface Waters of the Pacific and Indian Oceans,
M. Nesterova, I. A. Nemirovskaya, N. Anufrieva, and V. Maslov . . 75
Oil Pollution Studies in the Norwegian and the Greenland Seas,
V. M. Smagin and V. S. Rachkov 34
Study of Methods of Sampling Seawater from the Ocean's Surface Microlayer
and Results of Determination of Oil in Various Regions of the Atlantic
Ocean, V.I. Mikhaylov and S.G. Oradovskiy 92
Cesium-137 as a Tracer for Reactive Pollutants in Estuarine Sediments,
H. J. Simpson, C. R. Olsen, R. Bopp, P. M. Bower, R. M. Trier, and
S. C. Williams ^.02
The Distribution of Pollutants in the Caribbean Basin, M. M. Domanov,
B. A. Nelepo, and V. N. Stepanov
v
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Suspended Particulate Matter and Natural Radionuclides as Tracers of
Pollutant Transports in Continental Shelf Waters of the Eastern
U. S., Pierre E. Biscaye, Curtis R. Olsen, and Guy Mathieu 125
Trace Element Geochemistry of Continental Shelf Waters of the South-
eastern United States, Herbert L. Windom 148
The Flameless Atomic Absorption Method for Mercury Determination and
Its Use in Controlling Environmental Pollution, N. S. Poleuktov and
Yu. U. Zelyukova 159
The Scientific Principles of the Problem of Seawater Pollution, A. I.
Simonov and A. N. Zubakina 164
Monitoring of Marine Environment as an Information Basis for Economic-
ecological Control, M. T. Meleshkin, A. I. Simonov, A. M. Bronfman,
V. E. Glushkov, and A. L. Suvorovsky 183
Appendix
Protocol of the Working Meeting of Soviet and American Specialists . . 198
vi
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INTRODUCTION
Karl K. Turekian
Chairman, U.S. Delegation
There are a number of ways of trying to assess the impact of man's activ-
ities on living marine organisms. One direct method is to measure the direct
biological effects in the form of mortalities, inhibitions to activity, and
actual extinction of species. However, many effects can have less acute
influences that are nevertheless important over a long-time scale. Therefore,
the application of direct methods can be insufficient for studying the effects
of chemical pollution on the living marine environment. Various chemical,
biological, and physical methods for evaluating the state of the living and
non-living marine environment are used in research on this problem.
In order to assess changes in the "health" of the sea under the influence
of chemical pollution, we must know how it accommodates perturbations under
normal conditions. Only then can we try to assess the levels of acceptable
insults for which the natural assimilation processes will overcome the pro-
cesses that pollute the world's oceans, and predict the dynamics of the levels
of pollution.
U.S. and Soviet specialists working under the joint project "Effect of
Pollutants on Marine Organisms" approached the Symposium on Chemical Pollution
of the Marine Environment with an understanding of the scientific aspects of
pollution problems. The Symposium was held in Odessa USSR from May 24-28,
1977, and was organized in accordance with the Memorandum from the Fifth
Session of the Joint U.S.-U.S.S.R. Committee on Cooperation in the Field of
Environmental Protection.
The fluxes of metals, radionuclides, particulate material, and organo-
chlorine pesticides and hydrocarbons in estuarine systems are sufficiently
intense to require our special attention. These systems represent a region of
the sea heavily used by man in all his activities. Papers presented by the
U.S. members of the joint seminar concentrated primarily on problems of the
coastal and estuarine zone.
The papers presented by the Soviet specialists were concerned with a
discussion of problems associated with pollution in the open ocean, focusing
primarily on organic (mainly hydrocarbon) impacts. This approach demonstrates
the global character of chemical pollution of the oceans.
In this manner, the Soviet and American papers complement each other in
attempts to reveal the whole picture of pollution in the world's oceans.
-------
These two directions guaranteed the fruitful work of the Symposium and opened
the possibility of future collaborations. The members of the U.S. delegation
were pleased with the opportunity to conduct valuable discussions with their
Soviet counterparts.
-------
PROTOCOL
OF THE FIRST U.S.-U.S.S.R. SYMPOSIUM
ON
CHEMICAL POLLUTION OF THE MARINE ENVIRONMENT
In accordance with the principles laid down in the protocol from the
Working Group Meeting held in the U.S.S.R. in July 1976 and the Memorandum
of Implementation from the Fifth Meeting of the U.S.-U.S.S.R. Joint Committee
on Cooperation in the Field of Environmental Protection, a Joint U.S.-U.S.S.R.
Symposium on Chemical Pollution of the Marine Environment was held in Odessa,
U.S.S.R. from May 24 through 28, 1977.
The Symposium was co-chaired by Dr. Karl K. Turekian, Professor of
Geology and Geophysics at Yale University (U.S.) and Professor ^'ithony I.
Simonov, Division Director, State Oceanographic Institute (U.S.S'.R.). A list
of participants is attached.
The participants in the symposium presented papers on tracers of pollu-
tants in estuarine sediments and U.S. continental shelf waters; the fate of
heavy metals in estuaries and the Gulf of Mexico; transport of natural radio-
nuclides in shelf waters of the eastern U.S.; the distribution and dynamics
of trace metals in pore water and sediments; biogeochemical research on metals
in the world ocean; monitoring chemical pollution and forecasting its biologi-
cal consequences; arsenic, antimony and mercury in seawater; pollution of the
Caribbean Basin; oil and oil products in surface waters of the Atlantic,
Pacific and Indian Oceans; the forms of heavy metals in seawater (e.g.
mercury); methods of sampling water from the ocean surface microlayer and the
technical composition of the microlayer; a method for determining mercury;
scientific aspects of marine pollution problems; and the management of the
quality of the marine environment.
Stimulating discussions were held after each presentation. The partici-
pants in the symposium expressed the desire to conduct a Second U.S.-U.S.S.R.
Symposium on Chemical Pollution of the Marine Environment in two to three
years in the U.S. The following possible topics for this symposium were men-
tioned; transformation, fate of pollutants (oil and oil products, heavy metals
et al.) in the marine environment, in sediments, and in the surface micro-
layer; influence of pollution on physical and chemical processes; input of
pollutants from rivers to coastal and oceanic waters; fate and transport of
radionuclides; and methods for determining pollution in the marine environ-
ment.
During the visit of the American delegation to the U.S.S.R., the American
scientists visited the Institute of Economics of the Ukrainian Academy of
-------
Sciences, the R/V Victor Bugayev of the State Oceanographic Institute in
Odessa, and the Arctic and Antarctic Institute and its research vessel the
Professor Zubov in Leningrad.
The Symposium was held in an atmosphere of friendly cooperation and has
been of mutual benefit to both sides. The U.S. specialists wish to express
their gratitude to the Soviet delegation for such a well organized symposium
and for the gracious hospitality shown them during their visit. They also
wish to thank the interpreters for their excellent services.
This protocol was signed in Odessa on May 28, 1977, in two copies,
Russian and English, both copies being equally valid.
K. turekian
U.S. Chairman
A. Simonov
U.S.S.R. Chairman
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PARTICIPANTS
AMERICAN SIDE
Dr. Thomas W. Duke
Director, Environmental Research Laboratory
U.S. Environmental Protection Agency
Gulf Breeze, Florida 32561
Dr. Karl K. Turekian
Co-chairman of the Symposium
Professor of Geology and Geophysics
Department of Geology and Geophysics
Yale University
New Haven, Connecticut 06520
Dr. Michael L. Bender
Assistant Professor of Oceanography
Graduate School of Oceanography
University of Rhode Island
Kingston, Rhode Island 02881
Dr. H. James Simpson
Assistant Professor of Geological Sciences
Lamont-Doherty Geological Observatory
Palisades, New York 10964
Dr. Pierre E. Biscaye
Senior Research Associate
Lamont-Doherty Geological Observatory
Palisades, New York 10964
Dr. B. J. Presley
Associate Professor
Department of Oceanography
Texas A & M University
College Station, Texas 77843
Dr. Herbert L. Windom
Associate Professor
Skidaway Institute of Oceanography
University System of Georgia
P. 0. Box 13687
Savannah, Georgia 31406
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Dr. Richard Hittinger
Research Specialist
Graduate School of Oceanography
University of Rhode Island
Narragansett, Rhode Island 02882
Ms. Elaine M. Fitzback
Soviet Project Coordinator
Gulf Breeze Environmental Research Laboratory
Environmental Protection Agency
Gulf Breeze, Florida 32561
SOVIET SIDE
A. I. Simonov
Co-chairman of the Symposium
State Oceanographic Institute
Moscow
M. P. Nesterova
Deputy Co-chairman
P.P. Shershov Oceanology Institute, U.S.S.R. Academy of Sciences
Ye. A. Sobchenko
Director of the Odessa Branch of the State Oceanographic Institute
Odessa
M. T. Meleshkin
Economics Institute of the Ukrainian Academy of Sciences
Odessa
A. K. Prokof'yev
State Oceanographic Institute
Moscow
A. I. Bronfman
Economics Institute of the Ukrainian Academy of Sciences
Odessa
M. M. Domanov
P.P. Shershov Oceanology Institute, U.S.S.R. Academy of Sciences
Moscow
A. I. Zubakina
State Oceanographic Institute
Moscow
V. I. Mikhailov
State Oceanographic Institute
Odessa Branch
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N. P. Morozov
P.P. Shershov Oceanology Institute, U.S.S.R. Academy of Sciences
I. A. Nemirovskaya
P.P. Shershov Oceanology Institute, U.S.S.R. Academy of Sciences
Moscow
S. Go Oradovskiy
State Oceanographic Institute
Moscow
S. A. Patin
Ail-Union Fisheries and Oceanography Scientific Research Institute
Moscow
V, M. Smagin
Arctic and Antarctic Research Institute, Leningrad
Yu. V. Zelyukova
Physical-Chemical Institute of the Ukranian S.S.R. Academy of Sciences
V. Ye. Glushkov
Economics Institute of the Ukrainian Academy of Sciences
Odessa
A. L. Suvorovsky
Economics Institute of the Ukrainian Academy of Sciences
Odessa
M. K. Viktorova
Interpreter
S. M. Sheyman
Interpreter
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BIOLOGICAL INVESTIGATIONS OF METALS IN THE WORLD'S OCEANS
IN CONNECTION WITH MONITORING THE MARINE ENVIRONMENT
N. P. Morozov, S. A. Patin, and S. A. Petukhov
P.P. Shershov Oceanology Institute, U.S.S.R. Academy of Sciences
It is well-known that heavy and transitional metals, such as components
of the pollution of marine ecosystems, are subjected to man-made disturbances
affecting their concentrations and relationships in the environment of hydro-
bionts. These disturbances affect the natural content of corresponding trace
elements (for example, iron, manganese, zinc, and copper), many of which are
very important for the vital activity of hydrobionts. Therefore, monitoring
of marine pollution by metals and the interpretation of results are impossible
without analyses and generalization of data concerned with natural (back-
ground) levels of metal content in biotic and abiotic components in marine
ecosystems.
In this report, we attempt to solve this problem on the basis of bio-
chemical data obtained in laboratories of radiative and chemical ecology of
the Ail-Union Scientific Research Institute of Marine Fishery and Oceanog-
raphy.
Methods of sampling and preliminary treatment of water samples, particu-
late, plankton, benthos, nectone, and bottom sediments were similar to gener-
ally accepted procedures. Analyses were made by spectrophotometry with spec-
trophotometer Hitachi-207 and mercury analyzer Coleman MAS-50, according to
procedures described earlier (5, 6, 12) . The coefficient for the variation
of results of parallel counts was 10 to 20 per cent for different ecosystems.
Summarized results of the determination of 10 metals in samples of water,
particulate, and hydrobionts from different parts of the world's oceans are
presented in Tables 1 to 3 and in Fig. 1. The combination of data shows a
general picture of modern content and distribution of trace elements of the
metal group in marine and oceanic ecosystems. On the whole, our data agree
with published data (1, 2, 11, 14, 15, 16, 17). However, there are some
understandable discrepancies in methods, sampling, treatment, and analyses of
samples, as well as natural variation of metalic concentrations due to geo-
graphical, seasonal, and other factors.
For the North Atlantic, we showed that the spatial distribution of metals
in question is connected with the current system of the region (7). Data on
the Sea of Azov show that intensive summer bioproduction in shallow water may
lead to a notable decrease of a number of metals in water depth, due to bio-
sedimentation to the bottom. For this reason, relatively low concentrations
8
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Figure 1.
-2
-3
-4
-5
-6
-7
Cd
-8-Cdj
Mean metal concentration distributions with main components of seme marine and fresh water
ecosystems "rXnate-logarithms of mean metal concentrations; absciss-ecosystem components)
a. pelagium of the ocean;
1) marine waters;
2) particulate;
3) phytopiankton;
4) zooplankton;
5) fish (muscles);
6) fish (skeleton).
b. Sea of Japan:
1) marine waters;
2) particulate;
3) total plankton;
4) fish (muscles);
5) fish (skin);
6) phytobenthos;
7) zoobenthos (soft tissues);
8) zoobenthos (hard structures);
9) bottom sediments.
-------
-10
Figure 1. Mean metal concentration distributions with main components of some marine and fresh water
ecosystems (ordinate—logarithms of mean metal concentrations; absciss—ecosystem components)
c. Sea of Azov:
1) marine water;
2) particulate;
3) total plankton;
4) fish;
5) bottom sediments
d. Khasan Lake:
1) water; 5) phytobenthos.
2) particulate;
3) total plankton
4) fish;
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of zinc, copper, and nickel are found in Sea of Azov (Table 1), where seasonal
variations of trace element contents are possible.
Table 1 shows that the general order of magnitude and general sequence
of various metal concentrations in surface waters of different regions, with
salinity from 35 per cent (oceanic pelagium) to higher percentages (freshened
seas) are similar. These data also show a trend of the increased concentra-
tions of the majority of metals in both water and particulate at the transi-
tion from the oceanic pelagium to neritic zone and internal seas. This trend
follows a general geochemical regularity of the increase of the effect of
terrigenic freshwater run-off on chemical composition of marine water bodies.
At the same time, in accordance with published data (8, 9), a similar trend is
characteristic of a large-scale distribution of technogenic pollutants (metals
included) in the world's oceans. The problem of the role and relationship of
these factors in the formation of marine elements should result from chemical
monitoring, providing for each region's peculiarity.
The data in Table 2 are concerned with the content of heavy and transi-
tional metals in plankton biomass. They reflect rather high variability of
average concentrations undoubtedly connected with a diversity of the composi-
tion of plankton communities studied, and the process of bioaccumulation of
individual trace elements in phyto- and zooplankton organisms. Another pecul-
iarity of trace element composition lies in the predominance of elevated con-
centrations of metals in plankton of neritic and fresh water, compared to
oceanic pelagic populations. A similar trend was mentioned above for surface
waters. Finally, the last reason for a general conjunction of marine water
composition and plankton bionts lies in the fact that, in majority of cases,
one and the same sequence of decreasing concentration is followed in the
series iron-zinc-copper.
In general, the above is true for the ichthyofauna, although not to the
same extent as for plankton. Data presented in Table 3 illustrate typical
levels of metal contents in muscles and skeletons of commercial fish of the
world's oceans and fresh water.
A general picture of heavy metal concentration distribution in abiotic
and biotic components of various marine ecosystems, oceanic pelagrium, and
Seas of Japan and Azov is given in Fig. 1 (data on Khasan Lake are also pre-
sented for comparison). First, we note a similar variation of curves: the
largest concentrations of each of the metals are observed in particulate and
bottom sediments, then comes plankton, benthos, and fish. The greatest accum-
ulating capacity of particulate is connected with its higher dispersity and
the intensity of sorbing processes at the boundary of interface with water
medium. The physico-chemical nature of metal absorption is indicated in this
case by the fact that the particulate retains a typical relationship for the
marine water metal and their sequence in the series of concentrations. This
fact is indicated by a parallelism of lines combining mean metal concentra-
tions in water and particulate.
These data suggest that the trace element composition of ecological
groups of biotic population of marine regions generally reflects the content
and distribution of trace elements in nonliving components of ecosystems.
11
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TABLE 1. CONTENT OF HEAVY AND TRANSITIONAL MKTALS IN STJRFAOF WATFR AND PARTICULATE
Atlantic ocaan
(Kortharn part)
Pacific ocaan
Indian ocoan
Boaa
1MB fBIt*
eoaaxia mator
Baa of Japaa
^g^-*.
Earth Baa
.-Blaak Baa
tka Baltl* Baa
Baf af *la» .. -
BeattarxaB Baa
Baa af ten
Baa* for aartaa
Baaa far Jiaa>
ntar 1
Quantity af
tuplaa
•0
XI
a
15*
3
35
*jf
11
*
2O
*
Iran
aolT
at/1
5.0
5.6
4.5
5.0
5.0
6.5
•H.O
7.0
4.4
5.5
5.*
6.5
•TO
parti
•C *
&&
8Tt9
X m
c»
., J
2.7
4.0
3.2
3.6
1.1
o.s
7.0
part
•6
O.O"
O.Oli
O.U1J
O.O14
no
o.W»
5^
O.9
6"flj
i^jUJr
loO^O
r^ia-
Ilckal
aolv
1.7
1.9
2.0
1.0
2.2
P.5
uu
1.4
0.5
1.4
0.5
part
ag
0.0
J.005
u.uob
>.oo»
At.
B.SB6
.0%
g.»
8.««
.Mi
.M(
Jo&
.OIK
otft
."di
Cobalt
aalv
ag/
0.3
0.2
0.3
0.05
0.2
0.3
0.5
0.5
0.5
0.4
0.5
0.3»(
>art
«e
.Hfc
•Hn
Kn
^
0-1|i?8§i
Cor.
ao
M/
0.:
1.0
Altai
.fart
*S*
.tJ
.6fi3
=
bss
•9S
.8;
Laad
aol
Eg/
O.9
0.25
O.ZI
O.4
0.02
0.5
1.0
1.4
1.5
•3.0
1.*
3.0
part
ag *
0,12
O.OO'
O.O1
0,4
KW
0.6
o.oi;
0,7
.MS
M
~Ksk
"otJ*
S^
m
&441
Cadaioa
•ol
•e/
O.D
0.1
o.oa
0.1
1.5
O.2
0.3
0.2
1.5
part
*e
1.1007
CooT
O.fH
i.oJVS
0 W
.000
,4ci
.ofel
olc^
,01«
MJ1
Earcury
aol
•g/
0.07
O.I£
0.12
0.1
0^
0.6
0.3
0.14
0.17
0.1
0.3-
0.0!
part
Rafaraaca
Gi^o.^
— -a
.
Coldbarc.1932
Sl^^k
.
—. m
" .
•
_ '
•
-
*
Csldbarc a* al
- Ihlla ealeulatlac aoaa nlaaa for aatal eoataat la aarlaa watar data for Saa of Aao* «ara not takaa iato iiiniamiii
- «aan centant of aatala la ri.ni rater Dartlcolataa lac/1 and par cant) sara astiaatad froa data of G.S.XoanalcW.
-at al. (1966 a,») for 16 laraaat ttwa of tba OBB.
-------
TABLE 2. TRANSITIONAL AND HEAVY METAL CONTENTS IN PLANKTON OF OCEANIC, MARINE, AND FRESH WATER
(mg/kg raw mass)
Region
Atlantic Ocean
(Southern part)
Indian Ocean
Mean for
oceanic plankton
Sea of Japan
Bay of Peter the Great
Khasan Lake
Sample
charact .
phyto-
zoo-
phyto-
zoo-
phyto-
zoo-
total
total
total
Fe
7
63
214
137
110
100
55
226
378
.2
.6
.1
.0
.0
.0
.5
.2
0
1
1
1
1
1
0
0
19
Mn
.31
.15
.9
.8
.1
.5
.9
.9
.8
Zn
19
44
249
48
134
47
97
110
48
.0
.9
.0
.0
.9
.5
.1
Cu
5.8
3.5
29.3
13.6
17.6
8.6
5.5
12.1
31.5
Ni Co
6.
2.
2.
2.
4.
2.
1.
1.
2.
05
5
4 0.5
7 0.5
2 0.5
6 0.5
8 0.3
2 0.16
3 0.17
Cr Pb
1
8
2.8 14
2.0 1
2.8 7
2.0 5
1.7 11
11.6 13
2.25 1
.28
.85
.0
.4
.6
.1
.6
.7
.75
Cd
0.28
0.12
0.3
0.1
0.32
0.17
0.13
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TABLE 3. CONTENT OF TRANSITIONAL AND HEAVY METALS IN ICHTHIOFAUNA OF OCEANIC, MARINE, AND
FRESH WATER (mg/kg raw mass)
Quant.
Tissue of Samples Fe
Oceanic
Marine and
Semitransi-
tional
Fresh water
muscles
skeleton
muscles
skeleton
muscles
skeleton
50
50
41
41
24
24
14
30
32
121
51
105
.4
.4
.1
.9
.0
.8
Mn
0
3
1
9
2
12
.4
.7
.8
.6
.0
.1
Zn
14.
38.
37.
74.
59.
130.
8
5
3
2
8
4
Cu
0.9
2.1
1.2
2.7
1.0
2.4
Ni
0.
2.
2.
8.
1.
3.
7
1
3
1
2
2
Co
0
1
0
1
0
1
.2
.1
.4
.2
.2
.2
Cr
0.3
4.2
0.9
4.3
0.5
3.1
Pb
0,6
4.8
2.0
4,4
0.9
5,4
Cd
0.
0.
0.
0.
0.
0.
14
48
10
48
10
46
Hg
0.07
0.05
0.14
-------
This conclusion conforms with a general picture of chemical element distri-
bution in the marine biosphere (9). Almost always one finds in every area
that zinc and iron dominate among metals studied, while cobalt and cadmium
are present in minimum quantities.
The greatest variability of metal content is characteristic of bottom
fauna, which includes almost all species selectively concentrating chemical
elements. This variability may be connected with both diversity of chemical
composition of a biotope of benthos populations and peculiarities of their
mode of life (presence of sedentary forms), feeding habits (filtration
mechanism), and metabolism.
The data presented allow us to arrive at some conclusions and recommenda-
tions in connection with monitoring sea and ocean pollution by metals:
1. The system of observations of the content and dynamics of trace metals
in seas should be of a complex character and cover basic components of the
ecosystem, determining biogeochemical cycles in epipelagium of the ocean
(water, particulate, and plankton) and neritic zone (water, particulate,
plankton, and benthos).
2. In regions with large biomass and productivity (internal shallow seas
in particular), it is reasonable to combine chemical monitoring with simul-
taneous observations of the primary production, biomass, and species structure
of plankton communities.
3. Biological indications of anthropogenic disturbance of trace element
composition of the marine environment are mostly possible through analyzing
results of tests with benthos organisms that often come into contact with
concentrators of metals. Seston (particularly its nonliving component)
reflects the general variations (sequences) of concentrations and their
relationship in seawater.
4. Efforts in the field of monitoring metals in the world's oceans should
focus on the neritic zone and internal seas, where biogeochemical regional
anomalies of anthropogenic characteristics are possible. Oceanic pelagium
data should be interpreted as background on natural characteristics of metal
content in the marine biosphere.
15
-------
REFERENCES
1. Vinogradov, A.P. 1967. Introduction to Ocean Geochemistry. Nauka,
Moscow, p. 212.
2. Isibasi, M. 1968. Principles of Quantitative Distribution of Chemical
Elements in Seawater, including So-called Nutrient Elements.
In: Osnovnye Problemy Okeanologii (Basic Problems of Oceanology),
Nauka, Moscow, pp. 97-108.
3. Konovalov, G.S., A.A. Ivanova, and T. Kh. Kolesnikova. 1966.
Microelements in Water and Suspended Particles of the USSR
Asiatic Territory Rivers. Gidrokhimi-cheskiye Materialy
(Geochemical Materials), Vol XII, Leningrad, pp. 112-123.
4. Konovalov, G.S., A.A. Ivanova, and T. Kh. Kolesnikova. 1966. Rare
and Dispersed Elements (Microelements) in Water and Suspended
Particles of the USSR European Territory Rivers. Gidrokhimicheskiye
Materialy, Vol. XII, Leningrad, pp. 94-111.
5. Morozov, N.P.,and L.L. Demina. 1944. Extraction and Atomic Absorption
Spectrophotometric Methods Application Used to Determine Heavy
Metals in Seawater. Proceedings of VNIRO. Vol. 100, pp. 23-27.
6. Morozov, N.P., A.A. Tikhomirova, and Ye. M. Nikonenko. 1974. Determining
the Microelement Composition of Marine Organisms. Proceedings
of VNIRO, Vol. 100,pp. 28-31.
7. Morozov, N.P., S.A. Patin, and L.L. Demina. 1975. Transitional and
Heavy Metals in North Atlantic Waters. Proceedings COIN, Vol. 127,
pp. 77-94.
8. Patin, S.A. 1971. Pollution of the World's Oceans. Rybnoye Khozyaistvc
(Pishing Industry), No. 5, pp. 5-7.
9. Patin, S.A. 1973. Several Characteristics of the Metal Distribution
in the Ocean's Pelagic Ecosystem. Okeonologiya, Vol XIII,
Issue 2, pp. 255-258.
10. Patin, S.A. and N.P. Morozov. 1974. Several Aspects of Marine Pollu-
tion by Heavy Metals. Proceedings of VNIRO, Vol. 100, pp. 7-12.
11. Saukov, A.A., N. Kh. Aidinyan, and N.A. Ozerova. 1972. Synopsis of
the Geochemistry of Mercury. Nauka, Moscow, p. 335.
16
-------
12. Tikhomirova, A.A., S.A. Patin, and N.P. Morozov. 1976. Joint
Concentration and Determination of Mercury, Lead, and Cadmium in
Seawater. Zhurnal Analiticheskoi Khimii (Journal of Analytical
Chemistry). Vol. XXXI, 2, pp. 282-285.
13. Goldberg, E.D. 1972. Baseline Studies of Pollutants in the Marine
Environment and Research Recommendations. The IDOE Baseline
Conference, May 24-26, 1972, New York.
14. Goldberg, E.D., W.S. Broecker, M.G. Gross, and K.K. Turekian. 1972.
Marine Chemistry- Radioactivity in the Marine Environment.
National Academy of Sciences, Washington, D.C.
15. Spencer, D.W. and P.G. Brewer. 1969. The Distribution of Copper, Zinc,
and Nickel in Seawater of the Gulf of Mexico and Sargasso Sea.
Geochim. et. Cosmochim. Acta, Vol. 33, No. 3.
16. Szabo, B.J. 1968. Trace Elements Content of Plankton Population from
the Bahamas. Caribb. J. Sci., Vol. 8, No. 3-4.
17. Wolfe, D.A., and T.R. Rice. 1966. Nutrient Elements in Seawater.
Environ. Biol., No. 7.
17
-------
EFFECT ON THE DIAGENETIC STATUS OF SEDIMENTS
ON THE CONCENTRATIONS OF TRACE METAL IN PORE WATERS
Michael L. Bender
Gary P. Klinkhammer
Graduate School of Oceanography
University of Rhode Island
Kingston, RI 02881
ABSTRACT
As oxidation of organic matter in sediments
proceeds, dissolved interstitial oxygen, nitrate, and
S0,= are reduced in that order. In oxygen-bearing
pore waters, the manganese and iron concentrations
are very low due to the formation of insoluble oxi-
dized compounds. When oxygen is depleted, manganese
and iron concentrations rise. In sulfate-reducing
sediments, interstitial Cu, Cd, and Ni concentrations
are equal to or less than values in bottom waters,
presumably due to formation of insoluble sulfides.
Rates of release of metals to bottom waters
("benthic fluxes") have been studied by direct measure-
ment in the northeastern United States (Narragansett
Bay). In an area where diagenesis was proceeding by
sulfate reduction and a high interstitial vianganese
concentration was very close to the sediment-water
interface, the manganese benthic flux was found to
be great enough so that diffusion from sediments was
clearly an important source to the overlying waters.
Estimated upper limits for benthic fluxes of copper,
nickel, and cadmium indicated that release from sedi-
ments was not important in the balance of these metals
in the overlying waters.
Trace metals may be released to the water column from metal-rich wastes
dumpea in the nearshore environment. The rate at which metals are released
will depend on their concentrations in pore waters. Pore-water concentra-
tions, in turn, are controlled in part by diagenetic reactions in the sedi-
ments. The sequence of these reactions, predicted according to decreasing
release of energy per mole of organic carbon oxidized, is as follows:
18
-------
(1) 5(CH20)1()6 (NH3)16 (H3P04) + 690 02 + 530 C02 + 80
+ 610 HO
(2) 5(CH 0) (NH,)-_ (H,PO.) + 472 HN00 + 530 C00 + 276 N + 886 HO
z J-Uo J Ib o 4 z z z z
+ 5 H3P04
(3) (CH 0) (NH,)_, (H-POJ + 53 SO = + 106 HCO ~ + 16 NH + H PO
z .LUo j lo o 'i <\ 6 J J Q
+ 53 H2S + 106 H20
The pore-water constitutents that are most important in fixing trace
metal concentrations are 0 and S=. In the presence of 0 , Mn and Fe are
oxidized to the highly insoluble +4 and +3 oxidation states, respectively.
In the presence of S=, Cu, Ni, and Cd (along with other trace metals) are
expected to form insoluble sulfides (4). Iron and manganese are expected to
be more soluble in a reducing than in an oxidizing environment. The object
of this paper is to demonstrate that these expectations are followed in two
environments we have studied.
One of the areas studied, Narragansett Bay, is located on the Atlantic
coast roughly 300 km northeast of New York. Sediments at a site called
"Jamestown North," at a water depth of about 5 m, are largely unpolluted and
heavily mixed by burrowing worms, snails, and molluscs. We have done detailed
studies of pore water chemistry and benthic fluxes at this site.
Pore-water concentrations of £CO , S , NH , PO , and the metals Mn, Fe,
Ni, Cu, and Cd are shown in Fig. 1 for a short core (sampled at 1-cm inter-
vals to a depth of 15 cm) and in Fig. 2 for a long core (sampled at 5-cm
intervals to a depth of 100 cm). The data presented here are from diver-
collected cores. Sediment was removed from cores in a helium atmosphere.
Sediment samples were centrifuged at in situ temperatures to separate out
pore waters. The waters were filtered through 0.45 micron Nuclepore filters.
ECO was measured by gas chromatography; NH , P04=, and nitrate, were deter-
mined by colorimetry. Mn and Fe were measured by flameless atomic absorption
spectrophotometry without preconcentration, and Ni, Cu, and Cd were measured
by flameless atomic absorption spectrophotometry following preconcentration
by Co-APDC coprecipitation (3). Results are shown in Figs. 1 and 2.
At this site, concentrations of metabolites in pore waters are generally
constant to a depth of about 25 cm as a result of burrowing activity. Metab-
olite concentrations are fixed at a level where input by decay is balanced by
removal by the pumping activity of the infauna (which exchange pore waters
and bottom waters). Occasionally, as in core 11, the concentration of metab-
olites actually decreases with depth, due presumably to the metabolic release
rate decreasing with depth more rapidly than the pumping rate. At greater
depths, in the absence of pumping, concentrations increase and upward trans-
port is by ionic and molecular diffusion alone.
Although dissolved oxygen was not itself measured in the pore waters, the
EC02 results strongly suggest that oxygen is absent at depths greater than a
19
-------
0
PORE WATER DATA FOR JAMESTOWN NORTH CORE II
[SC02],mM [S'],^M [NHJ./iM [PO.-
I 2.4 2.0 0 2 4 0 40 00 1200 20
£
o 12
• I T^lO
O
o
o
o
o
o
o
o
o
o
o
o
o
o
o
o
4O CO
r"i
o
o
o
o
o
o
o
o
o
o
o
a. l6
Ul [MO], ppb [FeJ.ppb [cd], ppb |cuj , ppb [NI] , ppb
O A0 1000 2000 0 2000 4000 60000 .2 0 4 80246
u
IJ
o 4
tJ
8
12
16
1 1 IQ 1 0
o
o
_0
o
o
~o
_p
o
o
o
o
5
o
o
—
1 ° 1 1 1 o'
o
0
o
0
o
o
~ o
2
3
r
)
o
—
-A
o
7X
/ /
/ /
g
All but
3 sumples
<0.lp|»b
o
o
w
-
1" 1 1 1
'/I
o
o
_ • °
~ o
\
o
VI
_
71
/ 0
~'/l
I/I
~* o
o
~ o
^ .
Figure 1. Concentration of £.CO2, S , NH3, PO ^, Mn, Fe, Cd, and Ni in pore
waters from the top 15 cm at the Jamestown North study site
(Narragansett Bay).
2Q.
-------
PORE WATER DATA FOR JAMESTOWN NORTH CORE 12
[£C02], mM [ss] , mM
2 6 10 0 ;1 .00
0
20
4O
GO
e
o
80
x"
•71-1-1-1-1 p-r-r-i
1
o
- o
o
o
o
o
0
o
0
0
1
r
}
)
-0
o
o
o
0
o
0
T«
o
o
" o
_
Nll-j], mM f'O^J./tM
.'} ti 0 - •)() OD
T— r— ,
o
o
-
-
-
_
0
o
o
o
o
o
o
(i
X)
o
o
o
o
o
0
o
0
o
o
_ o
°- [Mn], ppb [pj.ppb [cd], ppb fcuj.ppb [Ni.ppb
^ ,,0 IOO 200 0 IOO 0 .40
i- 1 \J
UJ
ni
o 20
0
40
60
80
' ' ' 'o '
o
o
0
-O
0
0
_o
~o
-O
,
1
.
o
- o
o
o
_ o
o
- o
0
o
-
_ o
_ o
_ o
/
T 1
o
~,
7
7
J
r
f-
t
t
/
All but
1 sample
< O.I ppb
y/y
/ / /
7 / / ,
•f//
J / /
/ / /
// //
////
///
20 2 4
I 1
All
samples
< Ippb
..
rf\ / 1 o1 ' '
r~ / / /
// //
o
A.I but
J / f\ 3 sumplus
o <2p|>b
V//
/// /
'//.
^ ' / i
v//
'„
Figure 2. concentrations of rco , s", NH , P041, Mn, re, Cd, Cu, and Ni in pore waters from
the top 80 en at the Jamestown North study site (Narragansett Bay).
21
-------
few millimeters. The C02 concentration of bottom waters is 2.0 mM and the
0 concentration is .15 mM. Hence, when all 02 has been used in respiration,
the CO content of pore waters would rise to 2.15 mM. NO - reduction
(reaction 2) would result in a small additional increase tperhaps to 2.20 mM) ;
higher £ CO concentrations probably reflect organic matter oxidation by sul-
fate (reaction 3). ECO concentrations are considerably higher. Hence, 0
is apparently absent from the pore waters throughout the core (except at the
sediment-water interface, where it must be present due to downward diffusion
from overlying waters), and sulfate reduction is occuring throughout the sedi-
ment column. In the top 15 cm, sulfide is so efficiently scavenged that its
concentration is below the detection limit (3 yM). It is present in detect-
able concentrations below 20 cm, rising to a level of 600 yM at 70-cm depth.
Metal distributions are consistent with what we expect based on assump-
tions outlined above. In the top few centimeters of the sediment, manganese
and iron concentrations are very high —2000 ppb and 6000 ppb, respectively.
They fall rapidly to concentrations of about 20 ppb and 50 ppb, respectively.
Both manganese and iron diffuse downward into the sediments and must be
removed by precipitation; the phases removing these elements have not been
identified, although it seems likely that iron is removed as a sulfide. Con-
centrations of cadmium, copper, and nickel in Narragansett Bay bottom waters
are approximately 0.1 ppb, 2 ppb, and 3 ppb, respectively. Cadmium and copper
concentrations in pore waters generally are below the detection limit of 0.1
and 1 to 2 ppb, respectively, presumably due to scavenging by sulfides as
indicated above. Nickel concentrations generally fall close to the 2 ppb
detection limit, and it is not clear whether these concentrations represent
true values or only upper limits. In all cases there are spurious values
(for example, Cd concentrations of 0.15 ppb in the 11 to 12 and 12 to 13 cm
intervals of Jamestown North core 11), which are believed to reflect random
contamination.
Pore-water chemistry was also studied in cores from the Eastern Equator-
ial Atlantic on a cruise of the R/V Gyre. Concentrations of nutrients, ECO ,
and several metals were measured. Cores were extruded in a helium atmosphere
and pore waters were squeezed with Teflon Reeburgh-type squeezers. Nitrate
concentrations (actually nitrate plus nitrite) were measured by a Technicon
autoanalyzer. Trace metal concentrations were measured as described earlier
for Narragansett Bay pore waters. Nitrate profiles for these cores are dis-
cussed by Bender et al. (1) in terms of reactions 1, 2, and 3 above. Bottom-
water nitrate concentrations are about 22 yM_. Pore water concentrations
initially increase due to 02~oxidation of organic matter (reaction 1). They
then decrease due to downward diffusion and nitrate reduction (reaction 2).
Eventually nitrate concentrations reach a level of <1 yM, at which point
sulfate reduction (reaction 3) may commence. Oxygen is believed to be
present from the sediment water interface throughout the depth range where
3_ < 0 (z = depth) (1). This corresponds to a depth of about
dz2
6 cm for core G76-5-10GC1 and <3 cm for G76-5-24SC. Sulfide production is
believed to be zero as long as nitrate is present. Based on the low sulfide
concentration (<3 yM) observed in the sulfate-reduction zone of nearby cores,
sulfide is believed to be essentially absent from pore waters containing
22
-------
U)
PORE WATER DATA FOR EQUATORIAL ATLANTIC CORES
[N03~] • /<-M [Mn]« PPb [Fe]>
[Cu] • ppb
J3 20 40 0 500 IOOO 0 IOO O 4 8
0
G76-5-IOGCI
1° 05.1'N
8-11.6'W 2O
4956m
E
0
- 40
h-
O_
llJ
Q
1 1 1 0 l A 1 1 1 1
o o
o o
o 6
o A
)
o
o
o
o
o
~ o
o
-
o
5
'
^*
o
~ o
o
o
0
-
o
77
/ /
/
/ /
-/
/ /
/
y
//
//
y
^
i i
All samples
above 4Ocm
< 2,0 ppb
/
o
0
-
o
l i I0 i
O
o
0
O
O
~
o
0
o
~ o
-
o
Ul
cr °
O
o
OG76-5-24SC 1/2
A G76-5-24SC 2/2
2" 5O.9' N
6'41.0'W IO
4572m
2O
i : i i j I i i i
o &
O, '
oa,
Oft
-
6
oa
a
CA
J
J
—
>
-
3
A 0
A 0
AO
/
/ /
/ ,
/ /
//
//
/ /
A
A
/
'/
//
l l
All
samples
<20ppb
III!
A 0
A O
O
A
-
A 0
tf>
to
to
Figure 3. Concentrations of nitrate, Mn, Fe, and Cv. vs. depth in two cores from the eastern equatorial Atlantic.
-------
15 PM N03-.
In core 10GC1, manganese and iron concentrations are below detection
limits in the oxygen reduction zone and in the top of the nitrate reduction
zone. Within the zone of nitrate decrease, below the depth at which oxygen
is believed to be present, manganese concentrations rise to about 1000 ppb.
In core 10GC1, iron concentrations begin rising above the detection limit at
about the depth where nitrate concentrations decrease to <2 yM. In core
24SC, the base of the nitrate reduction zone is not reached and no rise in
iron concentrations is observed.
The copper profiles in these cores are far different than in the
Jamestown North cores. Copper concentrations are about 7 ppb near the
sediment-water interface and decrease to about 4 ppb at a depth of 18 cm
in core 24SC, and 2 ppb at a depth of 50 cm in core 10GC. The higher copper
concentrations are believed to reflect copper input from degraded organic
matter and skeletal debris. The absence of sulfide apparently allows copper
concentrations to build to levels appreciably higher than those found in
local bottom waters (probably about 0.1 ppb) (2) or in pore waters of sulfate-
reducing Narragansett Bay sediments.
In summary, pore-water trace metal concentrations correlate with sulfide
and apparent oxygen content in the expected way. In the oxygen reduction
zone and the top of the nitrate reduction zone of equatorial Atlantic cores
(10GC1 and 24SC) , iron and manganese are very low and the copper concentra-
tions far exceed bottom water values. In the middle of the nitrate reduction
zone of the two Atlantic cores, the manganese concentration rises abruptly.
The iron concentration increases in the sulfate-reduction zone of core 10GC1.
Dissolved iron and manganese concentrations are high in pore waters of
sulfate-reducing sediments in Narragansett Bay. Cu, Ni, and Cd concentra-
tions in these pore waters are less than or equal to values in the overlying,
oxygenated waters. Cu concentrations in sulfate-reducing, Narragansett Bay
pore waters are far below values in oxygen-reducing and nitrate-reducing
sediments from the eastern tropical Atlantic.
Benthic fluxes of metals at the Jamestown North site in Narragansett Bay
have been measured directly, according to procedure of Hale (6) and Nixon et
al. (7)- Results for manganese have been reported previously (5). The
apparatus used for the flux determination is a PVC pipe half, sealed by plates
on both ends and a flange around the base; the volume is about 27 liters and
the average height is 11 cm. The apparatus is placed over the sediment and
an "initial" sample is withdrawn. Three hours later, water inside the chamber
is mixed by a pumping procedure and a "final" sample is withdrawn. The flux
is calculated from the difference in concentrations of the initial and final
samples, the length of the experiment, and the height of the chamber. While
there are clearly many problems associated with these determinations, the
results are believed to provide a reliable first approximation of benthic
fluxes.
During the summer of 1975, benthic fluxes of metals were measured in a
series of 12 experiments at the Jamestown North study site. The results are
24
-------
given in Table 1. Average values for the Cd, Cu, and Ni fluxes are negative,
indicating that there is a net flux of these elements into the sediments
rather than a flux out. Upper limits for the release of these elements may
be estimated from the mean flux plus one standard deviation of the mean flux;
limits on fluxes thus estimated are +.0014, +.033, and +.029 yg cm~2 day-1
for Cd, Cu, and Ni, respectively. These upper limits are about two orders
of magnitude less than the Mn benthic flux, and about one order of magnitude
less than the Fe benthic flux.
Mn and Fe fluxes are much higher than those of Cd, Cu, and Ni, but do
not follow the relative pore water concentrations of Mn and Fe. The Fe con-
centration in the top centimeter of sediment is nearly three times higher than
that of Mn, but its flux is an order of magnitude lower. This is believed to
reflect rapid oxidation and precipitation of iron in the water column.
The average height of the water column in Narragansett Bay is about 10 m.
From this value, average concentrations of metals, and mean values or upper
limits for benthic fluxes, values (or upper limits) for the doubling time of
metals may be calculated. (For reference, the flushing time of Narragansett
Bay is about one month.) The doubling time calculated for Mn is about five
days. Hence it is clear that diffusion out of sediments is an important
source of dissolved manganese in the water column. On the other hand, the
minimum doubling times of Cd, Cu, and Ni are 2 to 3 times the flushing time
of the bay. Hence, diffusion out of sediments is apparently not an important
source of the burden of these metals in the water column. Iron is excluded
from this discussion because its distribution in the water column is not
well-known.
TABLE 1. BENTHIC FLUXES MEASURED AT THE JAMESTOWN NORTH STUDY SITE
AND ESTIMATED DOUBLING TIMES FOR Cd, Cu, Ni, Mn, AND Fe IN
NARRAGANSETT BAY
Mean flux and Concentration of Time for benthic flux
standard deviation dissolved metal in to double water column
(yg cm~2 day~-^-)* Narragansett Bay concentration
Cd
Cu
Ni
Mn
Fe
-.0029±.0043
-.009±.044
-.035±.064
2.1±0.8
.17±.23
0 . 1 ppb
2 . 0 ppb
3.0 ppb
10.0 ppb
> 71 days
> 57 days
> 100 days
> 4.8 days
* Based on twelve determinations.
t Calculated excluding one anomalously high value believed to reflect
contamination.
25
-------
REFERENCES
1. Bender, Michael L., Kent A. Fanning, Philip N. Froelich, G. Ross Heath,
and Valentine Maynard. 1977. Interstitial Nitrate Profiles and the
Oxidation of Sedimentary Organic Matter in the Eastern Equatorial
Atlantic. (In preparation.)
2. Bender, Michael L., and Christine Gagner. 1976. Dissolved Copper,
Nickel, and Cadmium in the Sargasso Sea. Journal of Marine Research
34, 327-339.
3. Boyle, Edward G., and John M. Edmond. 1975. Determination of Trace
Metals in Aqueous Solution by APDC Chelate Coprecipitation. In:
Advances in Chemistry Series, No. 147, Analytical Methods in Ocean-
ography, Thomas R. P. Gibb, Jr., ed., American Chemical Society.
pp. 44-55.
4. Elderfield, H., and A. Hepworth. 1975. Diagenesis, Metals, and Pollu-
tion in Estuaries. Marine Pollution Bulletin 6, 85-87.
5. Graham, William F., Michael L. Bender, and Gary P. Klinkhammer. 1976.
Manganese in Narragansett Bay. Limnology and Oceanography 21,
665-673.
6. Hale, Stephen. 1974. The Role of Benthic Communities in the Nutrient
Cycles of Narragansett Bay. M.S. Thesis, University of Rhode Island.
129 pp.
7. Nixon, S. W., C. A. Oviatt, and S. S. Hale. 1976. Nitrogen Regeneration
and the Metabolism of Coastal Marine Bottom Communities. In: The
Role of Terrestrial and Aquatic Organisms in Decomposition Processes,
J. M. Anderson and A. Macfayden, eds., Blackwell Scientific Publica-
tion, Oxford. pp. 269-283.
26
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THE FATE OF METALS IN ESTUARIES*
Karl K. Turekian
Department of Geology and Geophysics
Yale University, New Haven, Connecticut 06520
INTRODUCTION
From the geochemical point of view, an estuary is a reaction vessel in
which the mixing of stream water and seawater has consequences far beyond
simple dilution. Streams bring more than fresh water to the basin: they are
bearers of dissolved organic compounds and inorganic species; detrital
material including organic matter; iron and manganese oxide grains and
coatings, as well as the minerals from soil profiles. And the sea provides
the well-known dissolved chemical species that make it salty. Of these,
sulfate plays a special role in determining chemical pathways in the estuary,
especially in relation to biological activity in the sediment column. In
addition, the dynamics of estuarine circulation and the activity of benthic
populations force intimate contact between the water column and the sediment
pile.
All techniques capable of helping us to understand this complex system
are welcome, even when they yield results leading to diametrically opposite
conclusions. For, at this point of contradiction, we can see how much our
analysis of the system has been oversimplified or how we have structured too
artificial a framework to represent this complex reaction vessel.
One of the most pressing problems in estuarine geochemistry is the
behavior of the trace metals: stream supplies are modified, and the quality
and quantity of what is actually delivered to the open ocean is determined.
I think that one of the best ways to understand the behavior of trace metals
in estuaries is to study the behavior of manganese, iron, and the daughters
of the uranium (and thorium) decay series nuclides in the stream-estuary-
ocean system. These metals provide the opportunity to determine rate con-
stants in natural systems. We hope that these constants can be used in
modelling the behavior of other elements for which data are difficult to
obtain directly.
*To be published in "Estuaries, Geophysics, and the Environment," a report of
the Geophysics Research Board of the U. S. National Academy of Science,
Washington, D. C. 20418. Research supported by U. S. Energy Research and
Development Administration.
27
-------
TABLE 1. THE URANIUM AND THORIUM DECAY SERIES
Np
U
Pa
Th
Ac
Ra
Fr
Rn
At
Po
Bi
Pb
Tl
U-238 SERIES
U-238
45»«lQ*y
i
Th-234
24.ld
Pa-234
1.18m
r
U-234
2»8UOJ?
fh-230
7S2iU>S
Ra£26
I622y
Rn-222
3825d
\
Po-2!8
3.05m
Pb-2t4
26.8m
Bi-214
r 19.7m
r'o-2!4
1.6 » I0"*s
ff
,
Pb-210
22,3y
Bi-210
,5.0 d
Po-210
138.4 d
Jf
i
r
Pb-206
Th-232
Th-232
I39«l0»7
Ra-228
575y
Ac-228
6.t3h
r
SERIES
Th-228
^l.90y
i
Ra-224
3.64d
Rn-220
54.5s
1
Po-216
0.158s
1
Pb-212
I0.6h
65%
Bi-212
6 0.5m
35%
Tl-208
3. m
Po-212
3 0«i(rTs
Pb-208
U-235
J-235
I3»l0*y
i
Th-231
25.6h
Pa-231
;z«ioS
!
Ac-227
22.0y
SERIES
Th-227
|8-Gd
Ra-223
ll.4d
1
Rn-219
392s
i
Po-215
I83il0"ls
I
1
I
1
1
!
Bi-2!i '
2.l6m:
JRb-2lT Pt-2C7
36.1m; ; ^
1
T?-2C-7
4^9,-n
N)
03
-------
Manganese and iron readily undergo oxidation and reduction under the
conditions available in different parts of an estuarine system and are
generally abundant in the sediments. The anoxic sediments in which seawater
sulfate in pore waters is reduced by bacteria to form hydrogen sulfides also
reduce iron and manganese in the sediment to Fe+2 and Mn+2. As the concen-
trations of these ions are determined by the solubilities of their sulfides,
their concentrations are quite high in pore waters—a property of manganese
and iron but not of other common metal sulfides. (Manganese solubilities may
also be controlled by the stability of MnCO, rhodochrosite.) The release of
Mn+2 and Fe+2 into aerated waters by biological and physical mechanisms
results in their oxidation to Fe+3 and Mn+4, respectively, and their pre-
cipitation as oxides. The freshly precipitated iron and manganese oxides
provide highly reactive surfaces that sequester many trace metals.
One member of the uranium decay series of interest in modelling the
behavior of metals is 210pfc> (half life = 22 years)(Table 1). This nuclide is
supplied to aqueous systems in part by the decay of 222Rn mainly derived from
dissolved 226Ra. The atmosphere is the other source: the decay of 222Rn
(which continuously emanates from soils to the atmosphere) results in a
supply of 210pb that is transported to ground level by precipitation.
Another nuclide in the uranium decay series, 234i>h, is also of value in
predicting the behavior of trace metals in estuarine waters. Because it is
supplied to estuarine waters exclusively by the decay of dissolved 238u, an
-------
TABLE 2. SUMMARY OF BEHAVIOR OF 210pb IN GROUND WATER REGIMES BASED ON DATA*
RAIN Pb210 = 10 dpm/H,
EVAPORATION-TRANSPIRATION = 50%
INFILTRATION Pb210 = 20 dpm/£
LAND SURFACE
WATER TABLE
Pb210 = o.4 dpm/l Ra226 = i dpm/£
SHALLOW GROUND WATER
Pb210 = 0.04 dpm/£ Ra226 = 10 dpm/£.
DEEP GROUND WATER
T = 1 Month
*From R. B. Holtzman (1964) in The Natural Radiation Environment, fJ.A.S. Adams and M. Lowder, eds.
Univ. of Chicago Press.)
-------
lished, however, a measurable flux of metals to the stream may occur although
it may not be seen in the Pb concentration. On the basis of ^lOpfc esti-
mates in ground water, the mean residence time relative to adsorption is less
than a month. Some of this removal may be accomplished by roots of plants
and trees that then transfer 210Pb (as well as stable trace metals) to the
surface where they become part of the plant litter. Thus, as rock is disinte-
grated by the action of soil organisms, producing organic acids and carbonic
acid, some of the metals are absorbed by the vegetation. Subsequent decay of
this vegetal material provides an organic-rich material commonly called top
soil. This top soil is the repository of seasons of accumulation of vegetal
debris processed and reduced in volume by soil organisms. The residual
organic material itself is a strong sequesterer of trace metals. Using 210Pb
derived from atmospheric precipitation as a tracer, Benninger et al. (2) have
shown that virtually every bit of the 2]-0Pb supplied by precipitation is
retained by the top soil (Table 3).
TABLE 3: ATMOSPHERIC FLUX OP 21°Pb IN THE EASTERN U.S. BY
DIRECT MEASUREMENT AND ACCUMULATION IN GROUND
LEVEL LONG-TERM ^REPOSITORIES*
flux,,
Location dpjn/qm /yr Type o£_ jteasurernent_
New Haven, Conn.
East Haven, Conn.
East Haven, Conn.
Cook Forest St. Park, Pa.
Maryland
1
1
0.8
1
1.2
precip, & dry fallout
salt marsh profile
soil profile
soil profile
soil profile
*Compiled by Benninger et al. (3)
By the erosion of its banks, a tributary system transports sections of
the soil profile, including the top soil with its sequestered metals. A
material balance calculation of Pb in the drainage basin of the West Branch
of the Susquehanna River indicates that this nuclide has a mean residence
time of about 2000 years in the soil relative to transport by streams (7) .
As a stream moves its burden of minerals and organic-rich detritus to
the sea, it is continuously fed by ground waters that supply dissolved mate-
rials. However, additional chemical changes can occur in the channel itself.
Th© river bed is an environment where biological activity can deplete oxygen
in pore waters and thus supply soluble manganese and iron to the stream.
This is most effective in deeper and wider parts of the stream channel and
causes precipitation of oxidized manganese and iron on the suspended material
in the stream in a continuous manner down its course.
The act of cycling manganese and iron in the river, as well as the supply
of additional quantities of these elements in soluble form from ground water,
results in an efficient scavenging of trace metals from the stream onto parti-
cles. In the case of the natural tracer 2^0pb, it can be shown that its mean
residence time in solution in streams is about one day, and seems to be
coupled directly to manganese precipitation (7). Thus the rate constant for
31
-------
manganese precipitation (and possibly iron) may determine the rate constant
for the removal of many trace metals from solution. As manganese is
resupplied to the stream for reducing sediments along its course, a fraction
of the precipitated metals may also be released, thus providing a steady-state
soluble concentration of each of the metals. The low relatively constant con-
centrations of many trace metals in streams may be explained by this steady-
state process.
The trace element concentrations in the particles in streams are related
to both the manganese concentration and the organic matter concentration.
They are unrelated to the formal ion exchange capacities of the clay minerals
typically supplied from weathering profiles. Our early experiments in adsorp-
tion and desorption of trace metals on clay minerals in freshwater and sea-
water systems thus are incapable of explaining the major controls on trace
element transport as seen in real streams. It is doubtful if increasingly
sophisticated in vitro experiments of this kind will provide any new insights
into trace metal behavior in natural aqueous systems.
The particles in streams also act to modify the stream composition when
artificial injections of soluble trace metals occur (10). In the Naugatuck
River of Connecticut (a tributary of the Housatonic), the Ni, Co, and Ag
concentrations drop at least an order of magnitude from the point of injection
of industrial metal-rich acid wastes to a point 1 km downstream (Fig. 1).
The metals sequestered on particles are transported to the estuary. A strik-
ing example of this is seen in the high trace metal concentrations found on
suspended particles in the Rhine River as it transects The Netherlands (8).
/ig Co/L
NAUGATUCK
NEW HAVEN
Figure 1. The distribution of "dissolved" cobalt in the Naugatuck-Housatonic
river system. The Naugatuck River is heavily impacted by industry
and high in dissolved metals. The concentration decreases away
from the source of impact as the result of adsorption on particles.
32
-------
In summary, we see that the burden of trace metals supplied to an estuary
by streams comes primarily on particles. This in turn is related to the or-
ganic and manganese concentrations of the particles. By analogy with the
behavior of Pb in such systems, it is obvious that organic and manganese
oxide phases are strong sequesterers of trace metals. What occurs, then, as
this assemblage reaches the sea?
The Freshwater-Seawater Encounter
The physical boundary where a stream encounters seawater is hardly a
simple one. In most places, the action of the tides continuously changes the
encounter configuration; any strong change in stream runoff, on the one hand,
or the response of the sea to storms, on the other, has profound effects on
this interface.
Two diametrically opposite processes involving trace metals may occur at
the freshwater-seawater boundary:
(1) The precipitation of iron and manganese, and some other elements such
as phosphorous, aluminum, and titanium, has been shown to occur in both field
and laboratory experiments. This is ascribed to the formation and floccula-
tion of colloids as the increased ionic content of the saltwater alters
charge distributions (9, 4).
(2) The release of metals from particles at the seawater interface has
also been invoked to explain certain field observations (5). This process is
compatible with laboratory experiments in which trace metals adsorbed from
fresh water on clay minerals have been shown to release them as the total
cationic concentration of the solution increases. This process exists most
strikingly as the hydrogen ion concentration increases, but the encounter
with seawater does not normally decrease the pH of solutions. We have seen,
moreover, that the trace element burden must be carried by the organic- and
manganese-rich phases, not by clay minerals.
The field evidence for release of trace metals in the estuarine system
is the observation that suspended particles in some European estuaries
decrease in trace metal concentrations as the salinity increases (8). The
exact method of release is not specified but appears to be the destruction
of the metal-bearing phases rather than simple desorption. Such field exper-
iments depend, of course, on the assurance that only the stream-borne
particles are involved in chemical changes occurring progressively seaward.
If non-indigenous sediments are transported into the estuary from the open
sea, the change in composition of particulate matter thereafter may be due
to dilution—not chemical gain or loss on the stream-originating particles
alone. This is difficult to ascertain since the mineralogy, in a strict
sense, will not be different over a broad region of a shelf area, thus con-
founding the identification of sources. More importantly, the metal-bearing
phases cannot be diagnostically identified; therefore, a mixing curve of open
ocean particles poor in such phases with stream-borne particles rich in them
will not be visible mineralogically. Indeed the definition of the mixing may
well be the distribution of trace metals on the particles! It is clear that
analysis of particles for metals alone will not provide a singular answer to
this problem.
33
-------
Our study of the encounter of the Housatonic River with Long Island
Sound at one time seemed to provide direct evidence for release of metals
from particles at the boundary between freshwater and seawater. Both the
Housatonic and the open waters of Long Island Sound showed much lower con?-
centrations of cobalt, nickel, and silver than the mouth of the Housatonic
(Fig. 2). Although these results might still be interpreted as showing
release of metals, another explanation seems to be better.
NICKEL
Ug/D
Figure 2. The nickel concentration increases sharply at the mouth of the
Housatonic River. This is probably due to the release of metals
from particles at the freshwater-seawater interface. The mechanism
may be enhanced, if not actually controlled, by the presence of
salt marshes.
The mouth of the Housatonic River is marked by a very large salt marsh
area. The tidal range in this region is almost 2 meters—the largest ampli-
tude in Long Island Sound. In salt marshes (as in marine deposits), the
storage of metals is related to indigenous reducing conditions. Sulfate in
pore waters is reduced to sulfide, which is then sequestered by the ubiquit-
ously available iron found in mineral surfaces. At low tide, the top layers
of the marsh are aerated; at times of rainfall at low tide especially, the
sulfide phases in the marsh are oxidized and sulfate and associated metals
are solubilized. As the tide comes in, the process is terminated and trapping
of trace metals can reoccur. Metal-rich particles from the streams are con-
tinuously trapped in the salt marsh, and atmospheric precipitation adds an
additional burden. Thus a concentration halo of certain trace metals in sea-
water is maintained around the salt marsh environs.
34
-------
A similar process has been shown to occur on a horizontal scale in the
Scheldt estuary by Wollast (11). There, reduced iron derived from the sedi-
ment is transported seaward with sulfide particles in anoxic waters. As the
aerated open ocean water is encountered, the trace-metal-bearing sulfide
phases oxidized. A marked increase in dissolved copper concentration occurs
simultaneously with a sharp decrease in dissolved iron as oxidation, and pre-
cipitation of the oxide occurs. The pattern of trace-metal release or pre-
cipitation occurring at a river mouth thus can be a complicated one.
We must discuss one additional factor influencing the fate of metals at
the stream-estuary boundary. That is the hold-up time at the encounter. The
stream encountering the sea is essentially ponded to some degree before it
overflows or mixes with its saline barrier. During its holdup, reactions
typical of reservoir situations can occur. Metals (as well as silicon) are
removed from the water column, as seen in the Connecticut River (Fig. 3).
After the water leaves the system, by breaching or mixing with the salty
estuarine barrier, it essentially mixes conservatively with the ambient
estuarine waters. The influence of the tides appears to be paramount in pro-
viding the mechanism for holding up the stream water. It is not unreasonable
to expect that, in stream systems experiencing small tidal effects, the trace
metal concentration patterns during mixing are essentially conservative.
0
150
130
ugSr/L "°
™ 90
70
50
14
ppm Co l3
12
CONNECTICUT RIVER
DOWNSTREAM ^
o e
0.6 - °
ppm Si 05 L ° o
0.4 ^ ° Q
03
0.20
°>/L
0.15
0.10
0.05
0
I 5
L0
0.5
0
74 72 71 70 69 68 67 66 65 63
Figure 3,
Both metals and silicon decrease in concentration in the freshwater
tidally affected parts of the Connecticut River, This can be
ascribed to a reservoir effect based on width of the river mouth
and tidal cycling.
35
-------
The Larger Estuarine Mixing Basin
The large estuarine system is an important arena for further modification
of the water before it becomes a part of the open ocean system. Such systems
as Long Island Sound, Chesapeake Bay, and the Baltic Sea, although different
in many ways, share the common property of being very large mixing basins. A
mixing basin is subject to many of the same effects controlling the fate of
trace metals as streams and the stream-seawater encounter discussed above.
The extent of the modification depends on the length of time distinctively
estuarine processes have to act on the water column. A fast flushing rate
(i.e., completed in days) essentially makes the estuary a conduit. A slow
flushing rate (completed in weeks) makes it a standing body of water with
special properties due to the presence of seawater and tides.
It is the combination of biological activity in the sediment column and
physical movement of the waters by storms and tidal action that makes the
estuarine basin a particularly active region chemically.
Using 21Qpb from atmospheric precipitation primarily and 234^ from j_n
situ production from dissolved 238u as tracers, we are able to identify pos-
sible mechanisms capable of modifying estuarine water composition. The work
on 234Tll j_n L0ng isiand Sound by Aller and Cochran (1) clearly shows that its
residence time in the water column is about one day. This is the same order
of magnitude of time as that for: 210Pb in streams. The fact that no dissolved
210pb can be identified in Long Island Sound (Fig. 4) implies that it too is
rapidly removed in estuarine systems, resembling 234Tn j_n behavior. We will
assume that this is indeed true and search for an appropriate mechanism.
0.2B r
0.24 •
0.00
0 1 8 12 16 20 24
Suspended sediment (xlO~3g/kg)
Figure 4. A plot of the total 210Pb activity in Long Island
Sound water versus the amount of suspended sediment,
indicating virtually no dissolved 210pb in the Sound.
36
-------
It can be shown on the basis of material balance calculations that plank-
ton cannot be important in transferring ^lOpj-j (ancj presumably ^-^^Th) to the
estuarine floor. It does not seem likely that clay minerals are important
scavengers since, in the more propitious freshwater system, they do not seem
to be very effective agents.
The most likely agents appear to be the manganese and iron released from
the reducing sediments as they are oxidized in the water column and form fresh
precipitates. The precipitates deposit on suspended particles and there act
as scavengers for a large number of trace metals. On return to the ocean
floor, settling particles are reworked into the sediment by burrowing organ-
isms. When the manganese and iron are recycled by the reduction-release-
oxidation-precipitation steps, the trace metals carried down by the process
mainly remain trapped in the sediment column, as seen by the material balance
calculation for 210pb. Only when trace metal bearing sulfide particles are
oxidized in the water column is there a refluxing of the associated metals
to the waters again.
By this process, an extended residence of water in an estuarine basin
results in a scavenging of the metals from the water column into the sedi-
ments .
Some of the finest grained manganese and iron oxide particles, with
their associated trace metals, will be swept to sea. This seems to be veri-
fied by the material balance studies on man-made 55pe reported by Labeyrie
et al. (6). The deficiency in some coastal sediments may be due to loss to
the open ocean from the estuarine system. This manganese and iron could be
a prime source of supply for the ubiquitous ferromanganese nodules in deep
ocean deposits.
37
-------
REFERENCES
1. Aller, R.C., and J.K. Cochran. 1976. Th/ U Disequilibrium in
Near-shore Sediment: Particle Reworking and Diagenetic Time Scales.
Earth Planet. Sci. Lett., v. 29, p. 37-50.
2. Benninger, L.K. 1976. The Uranium-series Radionuclides as Tracers of
Geochemical Processes in Long Island Sound. Ph.D. Thesis, Yale
University, New Haven, Connecticut.
3. Benninger, L.K., D.M. Lewis, and K.K. Turekian. 1975. The Use of
Natural Pb-210 as a Heavy Metal Tracer in the River-estuarine System.
In: Marine Chemistry in the Coastal Environment. T.M. Church, ed.
Symp. Ser. 18, Am. Chem. Soc., Washington, DC. pp. 202-210.
4. Boyle, E.A. 1976. The Marine Geochemistry of Trace Metals. Ph.D.
Thesis, Massachusetts Institute of Technology, Cambridge,
Massachusetts.
5. Kharkar, D.P., K.K. Turekian, and K.K. Bertine. 1968. Stream Supply of
Dissolved Silver, Molybdenum, Antimony, Selenium, Chromium, Cobalt,
Rubidium, and Cesium to the Oceans. Geochim. Cosmochim. Acta 32,
p. 285-298.
6. Labeyrie, L.D., H.D. Livingston, and V.T. Bowen. 1975. Comparison of
the Distributions in Marine Sediments of the Fallout-derived Nuclides
55pe and 239,240pu. A New Approach to the Chemistry of Environmental
Radionuclides. In: Proceedings ERDA/IAEA International Symposium on
Transuranium Nuclides in the Environment, San Francisco.
7. Lewis, D.M. 1976. The Geochemistry of Manganese, Iron, Uranium,
Lead-210, and Major Ions in the Susquehanna River. Ph.D. Thesis,
Yale University.
8. Martin, J.M. 1971. Contribution a 1'Etude des Apports Terrizenes
d'Oligoelements Stable et Radioactifs a 1"Ocean. Ph.D. Thesis,
University of Paris, Paris, France.
9. Sholkovitz, E.R. 1976. Flocculation of Dissolved Organic and Inorganic
Matter during the Mixing of River Water and Seawater. Geochim.
Cosmochim. Acta 40, p. 831.
10. Turekian, K.K. 1971. Rivers, Tributaries and Estuaries. In: Impinge-
ment of Man on the Oceans, D.W. Hood, ed. John Wiley and Sons,
Somerset, New Jersey. pp. 9-73.
11. Wollast, R. 1975. Paper presented at IUGG, Grenoble, France, Sept. 1975.
38
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THE STRUCTURE OF ARSENIC AND STIBIUM
FIELDS IN THE CARIBBEAN SEA
A. I. Ryabinin and A. S, Romanov
Physical-Chemical Institute, Ukraninian S.S.R. Academy of Sciences,
Sevastopol, U.S.S.R.
Studies of arsenic and stibium fields in waters of the Atlantic and
Pacific Oceans (1-3) reveal their complicated structure, generally governed
by that of hydrological fields. Both elements, although chemical analogs,
are distributed in the ocean, independent of each other.
Variations of arsenic and stibium content are great in the studied
fields; therefore, the natural background of both elements in the oceans can-
not be characterized by their average concentration values only.
The Caribbean Sea has a rather complicated hydrological structure. At
the same time, the natural background of arsenic and stibium in seawater is
not yet known. Only single determinations of stibium are known (4) .
In July 1971, an investigation of arsenic and stibium was carried out
along the Mona Strait-Venezuelan coast section. Simultaneously, Ganson and
Paranichev (Marine Hydrophysical Institute of the Ukrainian S.S.R. Academy of
Sciences, Sevastopol) performed hydrological operations on the same section.
Water samples for analysis were taken from hydrological bathometers.
Investigated elements from the analyzed samples were concentrated by coprecip-
itating with ferric hydroxide (III). Arsenic and stibium of precipitate were
determined by an instrumental neutron activation method, using the routine
procedure (5).
Ninety-five water samples have been analyzed at five hydrochemical sta-
tions with two parallel ones. Figs. 1 to 3 demonstrate results of investiga-
tions by a diagram of the arsenic and stibium concentration distribution and
values of their ratio.
Hydrological investigations of the section made it possible to identify
several water masses.
A surface water mass had high temperature and salinity, reaching values
of 27.0° to 28.8°C and 34.7 to 36.0°/oo, respectively. Below this water
mass, a subtropical subsurface water mass with a high salinity core was
located at a depth of 75 to 200 m (36.91 to 36.95 °/oo). A subantarctic
water mass with an intermediate minimum of salinity (^34.8 percent) and a
typical temperature of 5° to 6°C was found at 600-900 m depths. All water
39
-------
masses observed in this section had a characteristic north-south slope of iso-
halines. For instance, salinity maximum of the surface layer in the south was
situated at 50 to 75 m depths, and in the north, at a depth of 150 to 200 m.
In this section, the entire deep portion of the sea was filled with water of
uniform salinity (-^35.0 /oo) .
DISCUSSION
Arsenic Field
In Fig. 1, the arsenic field is divided by isolines of concentrates 5 and
10 g As/Si into three fields having the following limits of concentrations:0.7-
5 yg/£, 5-10 ygA, and 10-39 yg/£ . In this section, the arsenic content ranges
widely from 0.7 to 39 yg/£. Non-monotony of the arsenic distribution is
characteristic of the entire field. The position of fields with character-
istic concentrations of arsenic is in good agreement with a structure of the
hydrological field.
Generally, the arsenic content does not exceed 5yg/£ in surface waters.
Fields with concentrations up to lOyg As/Si are traced only in the southern
portion of the section.
A subsurface subtropical mass has also low values of arsenic concentra-
tions (<_5yg/£). An exception to the rule was observed at a shallow water
( 520 m ) station in the northern portion of the section where arsenic was
found to be 11 to 37yg/£ at 60 to 100 m depths. High concentrations of
arsenic are characteristic of water mass cores identified from salinity.
Generally, the subantarctic water mass ( 600 to 900 m ) also has low
arsenic content though there are centers in which concentrations exceed
10ygAs/£ in the core.
It is particularly interesting to note that the arsenic distribution in
deep waters (>1000 m ) is characterized by constant salinity and is non-uni-
form. In these waters, a region with high arsenic concentrations (10 to
39yg/£), and two regions with low concentrations (2 to 4ygAs/£), are well
marked.
These data indicate that deep waters are, to a certain extent, differ-
entiated according to a factor such as arsenic concentration. The nature of
such differentiation can be revealed by special investigations. A similar
picture is observed at the same depths in the tropical Atlantic (1).
Non-uniformity and non-monotony of the arsenic distribution in the sec-
tion are also evident from Table 1, which contains the average values of con-
centrations for water layers of 0 to 100 m, 100 to 500 m, 0 to 500 m, 500 to
lower level, 0 to lower level.
The highest content of arsenic was found in deep-sea layers (below
500 m). Despite a comparatively small extension of the section (^270 mi), the
average arsenic concentrations vary noticeably from station to station. The
40
-------
HOMEPA
IT
Figure 1. Arsenic field in the Mona Strait-Venezuelan coast section: solid
lines, isolines of arsenic concentrations of 10 yg/&? dash lines,
isolines of arsenic soncentrations of 1 yg/&; figures in field,
values of arsenic concentrations
41
-------
arsenic content appears to increase in waters of coastal stations. Thus, when
moving from station I towards station V, the average concentration of arsenic
in 0 to the 500-m layer decreases only as far as station IV.
TABLE 1. THE AVERAGE VALUES OF ARSENIC CONCENTRATIONS (yg/ft).
Station number:
Layer, m
0-100
100-500
0-500
5 00- lower level
0- lower level
I
9.6
6.0
8.1
—
8.1
II
3.3
4.4
3.8
12.5
6.9
III
3.4
5.0
4.2
9.2
6.3
IV
5.3
3.0
4.0
6.6
5.2
V
4.4
6.8
5.2
6.5
5.8
Entire
section
5.2
5.0
5.1
8.7
6.5
On the basis of the above data, one can draw an important conclusion:
the average values of arsenic concentrations in the Caribbean Sea cannot
characterize its natural background content. The arsenic field has a com-
plicated structure in the Caribbean Sea. Variations of the arsenic content
are great (they reach multiplicity 55). Therefore, only the arsenic distri-
bution field can serve as a characteristic of the background content of this
element.
Stibium Field
In Fig. 2, the stibium field is divided by isolines of concentrations
0.5 and 1.0 ugSb/£ into three regions. The region of maximum concentrations
(1.0 to 1.5 pgSb/&) is not great. It is observed at a shallow water station
(Station I) as separate patches and at station III as one patch at a depth of
more than 1500 m. The region of minimum concentrations contains 0.1 to
0.5 pgSb/£. The character of the location of regions with different contents
of stibium is indicative of the fact that this element is also distributed
non-uniformly and non-monotonously throughout the section.
The structure of the stibium field is in good agreement with that of
water masses. Judging from the run of isolines, the 500m surface water column
resembles a laminated structure. Alternation of water layers with different
contents of stibium is observed here. Like some isohalines, a number of iso-
lines also have a north-south slope. This structure of stibium field indi-
cates that separate water masses can be characterised by the value of stibium
concentrations.
Deep waters of the Caribbean Sea are non-uniform as well. Regions of
high and low concentrations of stibium are observed here, and the run of iso-
lines has a distinctive feature.
Distribution of the average values of stibium content for conventional
water layers (0 to 100 m, 100 to 500 m, 0 to 500 m, 500 m-lower level, 0 to
lower level) is shown in Table 2.
42
-------
Figure 2. Stibium field in the Mona Strait-Venezuelan coast section: solid
lines, isolines of stibium concentrations of 0.5 yg/£; dash lines,
isolines of stibium concentrations of 1 yg/£; figures in field,
values of stibium concentrations.
43
-------
TABLE 2. THE AVERAGE CONCENTRATIONS VALUES OF STIBIUM
Station 'number:
Layer, m I II III
1 234
0-100 0.8 0.4 0.6
100-500 0.7 0.7 0.5
0-500 0.8 0.5 0.5
500- lower
level - 0.5 0.7
0- lower
level 0.8 0.5 0.6
Entire
IV V section
56 7
0.5 0.6 0.6
0.5 0.4 0.55
0.5 0.5 0.6
0.5 0.5 0.55
0.5 0.5 0.6
Distribution of the weighted mean concentrations of stibium over three
layers at four of five stations investigated was also non-uniform. In fact,
weighted mean concentrations of stibium are the same for deep-water stations.
High concentrations of stibium are typical of a shallow-water station (Sta-
tion I), as noted in analysis data in Fig. 2. Therefore, the average con-
centrations of stibium in the entire section of separated layers are equal to
the average concentration of the element in the sea (0.6
Thus, the determined non-uniformity of stibium distribution (concentra-
tion variations of 0.1 to 1.5 yg/£) does not allow us to characterize the
background content of stibium in the sea, using the average concentration.
The Field of Relative Values of As (yg)/Sb (yg)
As concentration/ Sb concentration ratios, characterizing the relative
distribution of these elements, are calculated from the data of Figs. 1 and 2.
Based on the calculated data, a diagram is constructed of the distribution of
As/Sb (Fig. 3) with isolines 5, 10, and 20, which divide the field of the
diagram into four regions.
It is evident from Fig. 3 that the core of subsurface subtropical water
mass (Stations III and IV) can be traced quite well from As/Sb values (5) .
Regions containing high values (34 to 46) of As/Sb were in deep seawater
(>1000 m) .
Previously, (1) As/Sb values equal to 20 to 50 were observed at the same
depths in the Atlantic Ocean.
The above data indicate that arsenic and stibium are distributed indepen-
dently of each other in the Caribbean Sea. As/Sb values vary from 1.5 to 50;
therefore, the average value of As/Sb cannot characterize the ratio of arsenic
to stibium in the Caribbean Sea.
44
-------
I
HOMEPft OTAHpM
I I JY I
Figure 3. The field of 'As/SlTValues in the section of the Mona Strait-
Venezuelan coast: solid lines, isolines of As/Sb values
figures in the field, As/Sb values.
45
-------
REFERENCES
1. Ryabininf A.I-f and A.S. Romanov. 1973< Arsenic and Stibium in the
Tropical Atlantic. Geochemistry, no.2, (In Russian).
2. Ryabinin, A.I., and A.S. Romanov. 1975. Arsenic and Stibium in the
Equatorial Pacific. In: Marine Hydrophysical Research, no.4 (71),
Sevastopol, published by the MHI of the Ukrainian S.S.R. Academy
of Sciences. (In Russian, English abstract).
3. Romanov, A.S., and A.I. Ryabinin. 1976. An Investigation of Arsenic
and Stibium in the Atlantic Ocean. In; Marine Hydrophysical
Research, no.l (72). Sevastopol, published by the MHI of the
Ukrainian S.S.R. Academy of Sciences. (In Russian, English abstract).
4. Shuts, D.F., and K.K. Turekian. 1969. Studies of the Geographic and
Vertical Distribution of Some Scattered Elements in Seawater by the
Method of Neutron Activation Analysis. In: G.Mero, Mineral Resources
of the Ocean, M., Progress. (In Russian).
5. Ryabinin, A.I., and A.S. Romanov. 1972. Neutron Activation Determination
of Arsenic and Stibium in Oceanic Water with their Preliminary Con-
centrating with Ferric Hydroxide (III). Journal of Analytical
Chemistry, no.l (In Russian).
46
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CHEMICAL FORMS OF MERCURY IN MARINE WATERS
A. K. Prokof'yev
State Oceanographic Institute
Moscow
One of the most characteristic properties of seawater is the constancy
of its chemical composition, which historically has developed very slowly.
Because of their enormous size, the world's oceans, until the middle of the
20th century, accepted with relatively few ill effects all the waste from
human economic activity. It is only in the last 10 to 20 years, when this
activity assumed a global scale, that a number of regions began to manifest
symptoms of a disrupted ecological equilibrium and cases of poisoning for
both man and representatives of the marine fauna.
Mercury is one of the most noxious substances discharged by man into
the ocean because of its effect on vital biochemical processes. It should
be noted that the attention of researchers and society has only recently
been drawn to the toxic effects of mercury (and heavy metals in general) in
the natural environment after massive mercury poisoning in Japan (Minamata's
disease).
In the marine environment mercury is present in the water in suspended
and colloidal particles, in bottom sediments, and in animal and plant
organisms. It is distributed by very complex and little-understood
mechanisms as a result of chemical, physical, physiochemical and biological
processes which supplement each other, compete and intertwine, but at the
same time differ considerably. The transformations can be so profound that
they involve a change in the oxidation state of mercury.
At the present time available chemical data and phenomenological models
do not permit an adequate prediction of the distribution of traces of heavy
metals and, in particular, mercury in natural waters, as they constitute
very complex electrolytic solutions including a variety of inorganic and
organic substances. Although metal traces enter natural waters as a result
of the weathering of rocks and volcanic activity, man introduces consider-
able amounts of these metals in certain regions. As soon as the rate of
penetration of traces of metals or their compounds into the water system
exceeds the natural cycle, pollutants may appear or unfavorable ecological
effects develop. These effects have already been observed in certain regions
of inland and coastal seawaters of industrially advanced countries as a
result of the discharge of metals or by the combustion of fossil fuels and
production of cement. The dumping of industrial, municipal, and agricultural
waste waters containing a variegated mixture of variable composition of
47
-------
chemically and biologically active inorganic and organic substances has
resulted in varied degrees of pollution.
In seawater, heavy metals can be adsorbed and bound chemically by
suspended and colloidal particles which are always present in it. These
equilibrium processes, which depend mainly on the concentrations of the
dissolved metals, their forms, other cations and anions, as well as on the
amount of these particles and their chemical and adsorption properties,
have been inadequately studied. Therefore, in this paper we will only
consider soluble forms of mercury and will omit numerous models for describ-
ing the distribution of mercury among various dissolved complexes as it is
impossible to confirm them experimentally. This problem is mainly due to
the lack of data on the equilibrium constants between mercury ions and
various ligands and on the activation energy of the reacting components.
Mercury exists in nature, and in seawater in particular, almost
exclusively in the divalent state. However, it is also found in very limited
amounts in the unoxidized (metallic) and formally univalent forms. These
three forms of mercury are related by the reversible disproportionation
reaction as follows:
Hg22+ N Hg°U) + Hg2+
with the equilibrium constant K = (Hg2+ ) = 6.0-10~3,2 which shows a marked
shift of the equilibrium to the left. However, this equilibrium can be very
easily shifted to the right by many reactions which tie up Hg +; for example
S2~, OH~, Cl~, and NH,, whose concentrations in seawater substantially exceeds
that of mercury. For this reason, compounds of Hg~ will be practically
nonexistent in seawater.
Metallic mercury is usually present in seawater, where its solubility
is 23.6 and 54.9 \ig/!i at 10°C and 25°C, respectively (30), arid where it
penetrates from air in which it is always present in vanishingly low concen-
trations, and also as a result of direct chemical and biological reduction
of Hg2+ ions in seawater. It should be noted that it dissolves much better
in hydrocarbons than in water. This fact may have unfavorable after effects
because of the concentration of mercury in oil-polluted regions. Mercury
reacts in nature at very slow rates with a number of nonmetals and, what is
particularly important, with oxygen, to form mercury oxide, thus changing to
a much more soluble state. On the whole it may be stated that the oxidation
state in which mercury will exist in nature depends on the redox potential
and pH of the medium and on the nature of the anions and other chemical
compounds with which it forms strong bonds.
The great stability of the Hg2+ ion in aqueous media is caused chiefly
by two characteristics. The first is related to the fact that mercury
characteristically forms covalent, not ionic, bonds. For this reason many
of its compounds boil at low temperatures and dissolve in organic solvents
better than in water. A second important property of this ion is its ability
to form very stable complexes with many of the anions and compounds found in
nature (Table 1).
48
-------
Table 1.
STABILITY CONSTANTS OF SEVERAL COMPLEXES OF DIVALENT MERCURY (2)
X Cl~ Bz Y
io16 1022 io30
Hg + + 4X = HgX4; K = [HgX !
NH
io19
]/[Hg2+] •
CN~
io41
• [X]4
As a consequence, there is an almost total absence of free Hg in
seawater. Calculations based on the instability constants of the chemical
state of metals have shown that their form in natural oxidizing waters can
be controlled by a combination of pH and pel. In seawater at a Cl concen-
tration of 18.0 g/.e, (pel = 0.289) and pH 8^_of the soluble compounds of
divalent mercury, there ar,e_ 92.4% of HgCl ~ , 6.3% of HgCl ~ 1.25% of HgCl ,
and less than 0.02% of Hg~ , HgCl and HgO'H 0 taken together. Figure 1 is
a diagram of the distribution for compounds of Hg"+ as a function of salinity
at pH 8, provided that all of the HgCl9 is dissolved in water (33).
ppm Cl" 100 200 400 800 5500 750O 20000
mw'TF 2.S2 5.64 11.28 22.56 98.7 2
-------
In the presence of sulfide ions, mercury precipitates as the very spar-
ingly soluble sulfide HgS, which, however, in anaerobic seawater can go into
solution by forming polysulfides; for example:
•-) _ Q HQ _
N > 0 (1) .
The same conclusion is also supported by the study of the reaction of
mercuric chloride with sulfur-containing a-amino acids in aqueous solution
by means of proton magnetic resonance (pmr) spectra, which are strongly
dependent on the pH (27). For example, while zinc and cadmium do not react
with S-methlycycteine and methionine in acid solution, and mercury forms 1:2
complexes with localization of the bond on the sulfur atom
n^COCtf ' n ~ lf2'
in alkaline solution all three cations form chelates of the composition 1:2
with coordination bonds M-0,N (I) , except mercury reacting with S-methyl-
cysteine to form a chelate (II) with Hg-S,N bonds
CH_S(CH.) CH-NH2-M+ CH s-
3 2 n ^ COC/ 3 ^ Hg
(I) M = Zn, Cd, Hg (II)
The fact that mercury forms different types of complexes in alkaline solution
is explained by the greater stability of the 5-membered Hg-0,N ring in compar-
ison with the 6-membered Hg-S,N ring, i.e., the configurational and confor-
mational stability of the complex as a whole is more important than the
strength of the individual bonds.
An all important part in the binding of metal ions in seawater is played
by organic carbon, which may be present in the dissolved state as well as in
the form of colloidal and suspended particles, The latter are usually in the
50
-------
form of natural organic substances such as humic acids. The colloidal
fraction of organic carbon usually is also classified as dissolved organic
carbon, since it is not blocked by the filtering of natural water samples
through a standard membrane filter with a pore diameter of 0.45 y. The
concentration of such combined "dissolved" organic carbon in seawater ranges
from 0.3 to 2.0 mg/£, (36),over 20% of it being in the form of colloidal
particles 0.001 - 0.45 y in size (32).
Depending on the pH of the water, the surface of the colloidal particles
may be charged or neutral as a result of the dissociation or hydrolysis of
the functional groups -OH, -SH, -NH , NH and -COOH, which are the constitu-
ents of natural amino acids. The picture is complicated by the fact that,
depending on the source, the organic colloids formed by the decay of plant
and animal tissues may have changing properties and a changing number of
different functional groups. The latter either generate a surface electro-
static charge that regulates surface adsorption or forms complexes. Therer-
fore, it is usually difficult to distinguish a metal species adsorbed on
colloidal particles from a chemically bound species (32).
Organic matter can bind up to 60 per cent of dissolved mercury in
coastal waters (15), and organic and inorganic colloidal particles can tie
up most of the cadmium, lead, and copper (6). The lower the molecular mass
of humic acids, the better they bind metals by complexing. Particularly
effective in this respect are fractions with a mollecular mass up to 500 (28).
The same behavior has been observed in the case of mercury (5). Nevertheless,
it should be noted that other things being equal, the ability of organic
matter to bind metals is strongly dependent on its origin.
Suspended particles of inorganic and organic origin usually bind metals
by adsorption, not complexing, since their organic protion consists of
substances of low oxidizing capacity that consequently have comparatively few
functional groups. Therefore, when they reach seawater with the river runoff
and industrial wastes, the heavy metal traces adsorbed on them pass into
water as a result of complex formation. Up to 95 per cent of zinc and cadmium
are thus desorbed (29).
In addition to forming a soluble mercury complex, soluble humic acids can
reduce it to metallic mercury in accordance with a first-order kinetic equa-
tion at a fairly slow rate (K = 0.009 h ) that depends only on the pH.
According to Alberts et al. (14), the reaction mechanism consists in the
action of three types of radical electrons of humic acid on Hg + (as demon-
strated by esr spectra).
Turning to an examination of organic derivatives of mercury with an Hg-C
bond (true organomercury compounds), one must note that only compounds of the
type RHgX and R Hg (R - organic radical; X - organic or inorganic acid radical)
can exist in the environment. It is interesting to note that similar compounds
of cadmium and zinc are very easily decomposed by oxygen and water, and there-
fore cannot exist in nature. The greater the stability of organomercurials to
water and air can be explained by the very low affinity of mercury for oxygen,
not by a great stability of Hg-C bonds, which are fairly weak (the bond energy
is 13-52 kcal/mole, depending on the radical). Nevertheless, under prolonged
51
-------
exposure to air, light, and heat, organomercuricals undergo an abiotic degra-
dation in the environment; their reactivity is strongly dependent on the
structure of the organic radical. Oxygen decomposes them in accordance with
a free-radical mechanism to form intercalation and degradation products (21).
R Hg + 0 > RHgOR
£t £
(CnH2n+1>2H9 + °2 ' CnH2n+l°H + CnH2n° + H*°
and ultraviolet (uv) light acts in accordance with the same mechanism, but
leads to the formation of free radicals and mercury
'R2Hg ?> R' + RHg' > R' + Hg
Of all the organomercury compounds in nature, a special role is played
by derivatives of methylmercury because of its biological activity. Methyl-
mercury causes chromosome damage (26) and is responsible for Minamata's
disease. Organic compounds of mercury with other radicals have been studied
very little, although their phenyl and butyl derivatives can be formed in
nature as a result of human economic activity.
Among compounds of methylmercury, seawater contains 98 per cent MeHgCl,
2 per cent of MeHgOH, and practically no MeHg , as shown on a distribution
curve for methylmercury compounds as a function of salinity at pH 8, provid-
ing that all of the MeHgCl is dissolved in water (Fig. 2) (33). This curve
closely resembles that of the distribution of HgCl?, except for the absence
of complex ions.
Methylmercury in seawater can be formed chemically by irradiating
mercuric acetate with uv light at 253.7 nm (or fluorescent light) (8).
Hg(OCOMe)2 > MeHgOCOMe + Me2Hg
or by exchange reactions with organosilicon, (11) organotin, and organolead
compounds (8),
Me3Si(CH2)3S03Na + Hg(OAc)2— MleHgOAc + Me2Si (CH2) 3S03Na
OAc
Me3Sn+ + Hg +- » MeHg+ + Me Sn2+
Transfer of the methyl group from the silicon compound takes place quatita-
tively and, surprisingly, has not been known previously for nonaqueous
solvents. The reaction with the tin derivative is described by a first-order
kinetic equation with respect to each reactant and can obviously take place
with other alkyl groupw as well, since it serves as a preparative method of
obtaining alkylmercury halides in nonaqueous media.
The great affinity of mercury for sulfur accounts for the fact- that even
at very low concentrations of the alter in natural waters, over 99 per cent
of methylmercury is bound in two sulfide compounds, MeHgS~ and (MeHg) at
52
-------
IOO
500
5000
20000
mM cr
PCIO.O
2.82
14.3
2,0
1.0
564
0
o
•H
-2
-'6
en
3
-4
— 5
-6
Fig 2. Logarithm of the ratio
of methylmercury compounds
to total methylmercury as
a function of chloride ion
concentration at pH 8 (33).
pH 5-9 (23) . In addition, methylmercury can react with sulfide ions to form
salts of tris(methylmercury) sulfonium (31), which is probably the most
soluble and hence the most labile of the methylmercury derivatives present
in the environment. It is in reversible equilibrium with the poorly soluble
bis(methylmercury) sulfide (1C
diss
= 10~7)
(MeHg)
(MeHg)2S
MeHg
The stability of methylmercury in nature is also confirmed by the fact
that in contrast to phenylmercury (10) , the most active thiol-containing
compounds do not split:
MeHgCl + RSH
PhHgCl + RSH
MeHgSR
RSHgCl
A very interesting property of methylmercuzy is the dependence of its
reactivity in water on pH, as has been clearly demonstrated in the reaction
with methionine (14). At pH < 2, methylmercury binds the thioester group
into complex (III); starting at pH 2, it begins to move along the methionine
S3
-------
molecule and probably reacts with the carboxyl group to form the compound (IV) ,
and at pH 8-9, methylmercury binds the amino group into complex (V) , which
on further increase of pH begins to dissociate and breaks down completely at
pH 13.5:
^0
MeSCH2CH2CHC02H - N MeSCHCHC, • HgMe
HgMe +
(III)
MeSCH2CH2CHC02
(V)
MeHgNH-
The structure of the complexes has been demonstrated on the basis of the
chemical shifts of protons in the CH,~ and CH groups of mehtionine and
methylmercury, as well as the constants of spin-spin interaction between the
nuclei of mercury and hydrogen in esr spectra. The marked pH dependence of
the complexing of methylmercury with methionine and other amino acids common
in nature is due to the protonation of the ligand and the reaction of MeHg"1"
with OH~. The stability of these complexes at pH 7 and. 9 decreases in the
series sulfhydryl > amine > carboxyl > thioester when these groups are
jointly present (Ref . 14 and references sited therein) .
The structure of methylmercury complexes with ct-amino acids has been
confirmed by X-ray analysis. Methylmercury is bound to A-cysteine via the
sulfur atom
MgHgSCH2CH($H3)C02~ -H20,
and to d,£-methionine, via the nitrogen with the structure of (V) (25), d,£-
Penicilamine reacting with mehtylmercury forms two 1:1 and 1:2 complexes
(37, 38); in the 1:1 complex, the bond is formed via the sulfur atom
MeHgtSCMe^CH^HjCO,"] • HLO,
2. J * £.
and in the 1:2 complex, via the sulfur and nitrogen atoms
MeflgSCMe2CH (&H2) CO ~
HgMe
Hence, a-amino acids are capable of binding two mathylmercury groups. In all
these complexes, a weak coordination bond is probably formed between the
mercury atoms and the, oxygen of the carboxyl group, the C-Hg-S fragment is
almost linear, and the amino acids themselves are in the zwitter ion form.
In contrast to Hgp+, which binds two amino groups, (see above) , MeHg+ binds
only one, indicating its lower Lewis acidity.
One of the most important chemical properties of methylmercury is the
reversible symmetrization reaction
2MeHgX + 2L - > Me2Hg + HgX2L2
54
-------
The role of symmetrizing agents L is to effectively bind the inorganic mercury
salt by complexing, precipitation, or reduction in order to shift the equil-
ibrium to the right. In nature, such agents can be cyanides, iodides, amines,
and phosphines. Alumina is also active. However, precipitation materials and
sulfur-containing compounds are not. Therefore, Me2Hg in nature is chiefly
formed via methylcobalamin (10), and this promotes its fairly good solubility
in seawater (2.1 g/kg) (35).
In nature, methylmercury derivatives can be formed not only chemically
but also biochemically; the latter mode is the object of the most serious
study at the present time. The majority of researchers believe that methyl-
mercury is the cause of poisoning of numerous aquatic organisms since it has
been found in tissues bound to sulfhydryl groups of proteins. Its great
toxicity in comparison with metallic or inorganic mercury is explained by a
solubility that is two orders of magnitude greater in fats than in water,
thus considerably facilitating its penetration into cells.
It was shown previously that Hg2+ is methylated by methpentacyanoeobal-
tate prepared as a model of vitamin B12 (18). Subsequently, it was found that
this reaction takes place in natural systems (19, 40) in the presence of only
those microorganisms whose enzyme studies contain the coenzyme methylcobalamin,
the methylated form of vitamin B12. This is explained by the fact that of all
the known methylating reactants present in biological systems, only methyl»Bl2,
which belongs to the class of raethylcorrinoids, is able to transfer the methyl
group in the form of an anion, i.e., CH3" (20, 22, 39). The mechanism of this
reaction consists in an electrophilic attack on the methyl anion by the
mercury ion and is common in the chemistry of organornereury compounds,
A study of the reaction kinetics showed that the rate of transfer of
methyl anion depends on the equilibrium constant K, the slow reaction being
1000 times slov/er than the fast reaction. Dimethylmercury is formed similarly.
but only from MeH'g+, at a rate 6000 times slower than the rate of synthesis of
methylmercury (Bz-5,6-dimethylbenzimidazole) (34, 39) s
MeHg+
slow
fast Hg-' ^ reaction
reaction
Microbial methylation can occur under aerobic as well as anaerobic
conditions (7). It is proportional to the rate of growth and metabolic
activity of the methylating microorganisms, temperature, concentration of
mercury ions, their accessibility, and presence of organic matter. The
55
-------
optimum concentration of the latter is estimated from the biochemical oxygen
demand and equal to 8 mg/£ or more (33). Methylation takes place best at
pH 4.5. Certain bacteria form methylmercury from phenylmercury, and with
greater ease than from inorganic mercury (13).
The biochemical methylation of mercury occurring under natural condi-
tions may present a serious threat in the inland and coastal waters where
mercury is discharged with waste waters. Locations have already been identi-
fied where the mercury thus dumped and held by silting deposits is methylated
in a few years instead of a few centuries (9). This disrupts the natural
equilibrium and leads to the concentration of mercury in aquatic organisms
such as mollusks, seaweed, and fish, whose consumption by man may lead to
serious poisoning. Waste waters also pose another danger in that by supplying
methylcobalamin-containing nutrients to microorganisms , they promote their
multiplication and help to maintain anerobic conditions which protect
methylcobalamin from irreversible photochemical breakdown in the presence of
oxygen. Attempts to prevent the biosynthesis of methylmercury unfortunately
have proven unsuccessful. For example, the binding of inorganic mercury into
mercury sulfide merely leads to a decrease in the reaction rate by several
orders of magnitude (12) .
The ability of certain microorganisms to mineralize methylmercury to
metallic mercury and methane (24) unfortunately cannot prevent the accumula-
tion of mercury in aquatic organisms because the rate of formation of methyl-
mercury in nature exceeds the rates of its decomposition.
The formation and decomposition of methylmercury are not the only
natural biological processes in the transformation of mercury. Thus, the
enzymes present in many bacteria reduce divalent mercury to the metallic
state; the reduction of nicotinamide adenine dinucleotide (NADH) is used as
a coenzyme for catalysis, and certain microorganisms oxidize mercury sulfide
to the sulfate, causing the mercury in the latter case to go into solution
(see the reference in 39):
Hg2+ + NADH + H+— xHg° + 2H+ + NAD*
\ """••*
HgS—-—^HgSC>4.
Ignoring the metal species leads to serious errors in the determination
of their total content in seawater. It is well-known that the majority of
heavy metals in aqueous media are adsorbed and chemically bound to organic
and inorganic colloidal particles. It has always been assumed that heavy
metals can be quantitatively concentrated either by passing the samples
through cation exchange resins or by complexing them with various organic
compounds, mainly chelates, and by liquid extraction. However, it has been
shown quite recently by means of radioisotopes that resins of the type
"Chelex-100," most widely used abroad (in the USSR, their prototype is the
KU-2 resin), block only the dissolved and labile inorganic species of zinc,
cadmium, lead, and copper, and allow the ions of these metals bonded to
colloidal particles to pass through. This is because in most cases the
dimensions of the latter are too large to permit them to enter the pores of
the high molecular resin molecules where the cation exchange takes place.
56
-------
A similar situation is observed in the case of the most frequently
employed extraction of heavy metals by means of ammonium pyrrolidinedithiocar-
bamate in methyl isobutyl ketone at pH 4.5. Under these conditions, only
copper is completely extracted, while lead and zinc are extracted only to the
extent of 35-65 and 23-59%, respectively. The extraction with chelate in
comparison with resin is more effective only because organic colloids dissolve
in the ketone. To achieve a complete separation of heavy metals from
colloidal particles, the latter must be broken up. The breakup is accomplished
by boiling the samples in strongly acidic solutions at pH 0.7, then alkalizing
to pH 4.5-8.1 and concentrating either on a resin or by complexing (16). This
behavior will also undoubtedly apply to mercury, although the latter was not
considered in the study.
It was also found that among minerals containing organic matter and
sulfur compounds, mercury for analysis can be quantitatively separated only
by treating the samples with aqua regia or with oxidizing mixtures containing
chloride ion (3). This would also undoubtedly apply to samples of seawater
and bottom sediments as well.
Researchers have determined the total content of mercury (and other
heavy metals) in objects in the environment with indefinitely low results
(3 and 16). Their studies should apparently lead to a serious revision of
the concepts based on the reliability and accuracy of methods of quantitative
determination of heavy metals in objects in the environment, for example, the
calculation of their balance.
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Spectra of 35C1, 79Br, 81Br, and 127I of the Complexes HgHaI2.XCH2CH2X, X=
OMe, SMe, NMe2. Izvestiya AN SSSR, ser. khim., No. 8, pp. 1895-1897.
2. Cotton, F., and D. Wilkinson. 1969. Modern Inorganic Chemistry, Part
II. Mir, Moscow, pp. 464-487.
3. Agemain, H., and A.S.Y. Chau. 1976. An Improved Digestion Method for the
Extraction of Mercury from Environmental Samples. Analyst, Vol. 101,
No. 2, p. 91-95.
4. Alberts, J.J., J.E. Schindler, and R.W. Miller. 1974. Elemental Mercury
Evolution Mediated by Humic Acid. Science, 1974, Vol. 184, No. 4139,
p. 895-897.
5. Andren, A.W. and R.C. Harriss. 1975. Observations on the Association
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Chemistry, Vol. 4, No. 4, p. 347-363.
57
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7. Bisogni, J.J., and A.W. Lawrence. 1975. Kinetics of Mercury Methyla-
thion in Aerobic and Anaerobic Aquatic Environments. J. Water Pollut.
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Reactivity of Organometals in Aqueous Media. Seventh Inter. Conf.
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60
-------
THE PATE OP HEAVY METALS ADDED TO THE
GULF OF MEXICO BY THE MISSISSIPPI RIVER
B. J. Presley and J. H. Trefry
Department of Oceanography, Texas ASM University
College Station, Texas 77843
Anthropogenic heavy, metals, along with other materials, may be trans-
ported to the ocean from continents by atmospheric processes, direct dumping,
sewage outfalls, storm runoff, and river and ground-water discharge. The
relative importance of these pathways for most substances is not well known.
However, there is general agreement with the suggestion of Dyrssen et al. (4)
that atmospheric transport may be mainly responsible for addition of pollu-
tants to the open sea, whereas the other routes are probably more important
to coastal waters. River discharge is certainly dominant in total transport.
Garrels and MacKenzie (9) estimate that rivers carry 90 per cent of the total
dissolved and suspended solids that are added to the oceans. Rivers also
carry domestic and industrial wastes away from most major communities, and
thus must be responsible for much of the man-derived substances added to the
ocean.
The major U.S. river is the Mississippi which drains 41 per cent of the
conterminous U.S. Its drainage basin stretches from New York to Montana and
from Canada to the Gulf of Mexico (Fig. 1). The Mississippi is estimated to
carry about 60 per cent of the total dissolved solids (16) and 66 per cent of
the total suspended solids (3) transported to the oceans from the conterminous
U.S. Estimates of industrial, municipal/ and agricultural waste inputs into
the Mississippi River (8) suggest that the river pollutant load is large and
diverse. For example, recent data show that river phenol concentrations con-
sistently exceed public water supply criteria (25) and that the river has a
significant anthropogenic contribution of light carbons (2) and phthalic acid
esters, DDTs, and PCBs (10). Added to this load is the domestic sewage from
almost 2 million people in the lower Mississippi area alone. In addition to
organic substances, an estimated 18 million kilograms of inorganic wastes also
discharged into the lower Mississippi River daily (8). This flux is equiva-
lent to 7 per cent of the total dissolved load at average river flow and 21
per cent of the total at low flow. Little data are available on the chemical
composition of this industrial discharge; however, such wastes are known to
contain various heavy metals (19).
The work presented here characterizes and quantifies the particulate and
dissolved metal load of the Mississippi River and examines metal distribution
in Mississippi Delta suspended matter, plankton, and sediments. The overall
objectives of this work are to assess the magnitude .of any anthropogenic metal
contribution by the Mississippi River and to determine its fate in the Gulf of
Mexico.
61
-------
Figure 1. Large rivers in the United States (15)
-E9
Suspended matter
and water stations
28*-
Figure 2. Mississippi River and Delta water, suspended matter, and sediment
sampling sites.
62
-------
Mississippi River dissolved metal concentrations from locations shown in
Fig. 2 were found to be low and, with the exception of Zn, are considerably
below those established for water quality criteria (Table 1). The dissolved
fraction accounts for <10 per cent of the total river metal load for most
metals studied (Table 2). This is most likely due to the adsorption of metal
species on the abundant river suspended matter (>300mg/£) at the relatively
high river pH (7.5 to 8.0).
River particulate metal concentrations (Table 1) were constant during
four sampling periods when the river was at average and above average flow.
During low flow, an increase in particulate organic matter concentrations
(from <3 to 25 per cent) brought about a corresponding decrease in Fe and Al
concentrations due to dilution of alumino-silicate detritus and a 30 to 40
per cent increase in Mn, Zn, and Cu concentrations due to an association of
these metals with the increased organic matter. Of the metals studied, only
Zn was found in concentrations higher than those accepted as suitable for
dredged sediment disposal. Dumping criteria based on bulk chemistry ignore
the geochemical form of the metal and do not necessarily predict the biologi-
cal availability of excess metal loads, but point out unusual concentrations
indicative of man-introduced material. Three metals (Zn, Pb, and Cd) were
found to be in much higher concentrations in the river particulates than in
average continental crust (Table 1).
Physio-chemical interactions involving heavy metals, reportedly occurring
across the freshwater/seawater interface, may affect both the ultimate area of
metal deposition and their availability to nearshore marine organisms.
Desorptive processes would make metals more available to organisms and delay
their removal to the sediments, whereas adsorptive processes would have an
opposite effect. Comparison of our suspended matter data from the Mississippi
River with that in saline waters from immediately outside the river mouth
(Table 1) shows that (with the exception of Cu and Zn) concentrations are
essentially the same. These observations argue against extensive desorption
of any of these metals and suggest that Cu and Zn levels actually increase in
particulates from salt water, perhaps due to the increased percentage of
organic carbon.
It has long been known that marine plankton greatly concentrate certain
trace elements from seawater (26, 11). There has also been considerable
speculation on the importance of plankton in transporting trace elements from
surface to deep water or from water to sediments (12, 1). Thus, plankton are
potentially a key factor in removing pollutant metals from seawater.
Phytoplankton collected from the Mississippi Delta area and the north-
west Gulf of Mexico (Fig. 3) had quite variable trace metal concentrations,
but similar values and variability have been reported in other studies (14,
17).
Previous works have found little correlation between trace metal concen-
trations and the species composition of phytoplankton samples, and that gener-
alization holds for the Gulf of Mexico samples. There seems, however, to be
an indication of Pb enrichment in samples from near the river mouth. For
example, samples 8, 9, and 11 (Table 3), which were collected on the same day,
63
-------
TABLE 1. MISSISSIPPI RIVER DISSOLVED AND PARTICULATE METAL CONCENTRATIONS AND ENVIRONMENTAL QUALITY
CRITERIA
Dissolved metal concentrations
Mississippi River (N=10)
Water quality criteria
(EPA, 1973)
Ave. river water
(Turekian, 1974)
in Vg/#
Fe Mn Zn Pb Cu Ni Cr Cd Hg
10 10 10 1 2 1 0.5 0.1 0.5
300 50 1 30 60 100 50 4 2
7 20 3 7 0.3 1 - 0.07
Parti culate metal concentrations in Pg/&
Mississippi River CN=34)
Mississippi Delta (N=34)
Fe Mn Zn Pb Cu Ni Cr Cd Co
46,100 1,300 193 45 45 55 80 1.3 21
46,400 1,290 244 49 56 56 84 1.5 21
Sediment disposal criteria
(EPA, 1973) - - 75 50 50 - - 2
Ave. crustal abundance
(Taylor, 1961) 56,300 950 70 13 55 75 100 0.2 25
-------
TABLE 2. ANNUAL FLUX OF METALS FROM THE MISSISSIPPI RIVER TO THE GULF OF MEXICO*
Element
Fe
Mn
Zn
Cr
Ni
S Cu
Pb
As
Cd
Particulate
( x 109g)
12 , 900
364
54
22
16
13
13
4
0.4
Dissolved
( x 109g)
5.7
5.7
5.7
0.3
0.6
1.1
0.3
0.6
0.06
Particulate
(% of total)
99.9
98.5
90.4
98.7
96.4
92.2
97.7
87.0
87.0
Dissolved
(% of total)
0.02
1.5
9.6
1.3
3.6
7.8
2.3
13.0
13.0
Calculations are based on average water and suspended matter data from Table 1 with the sediment
discharge data of the U.S. Army Corps of Engineers (2.8 x 1014g/y; 1950-1974) and estimated water
flow at the river mouths (5.7 x 10 Vy; Iseri and Langbein, 1974).
-------
30'
25'
20°
95°
90°
85°
80°
Figure 3. Location of plankton sites in the northwest Gulf of Mexico and the
Mississippi Delta.
show a three-fold decrease in Pb to Al ratio in moving away from the river.
The pattern of Pb concentration around the river mouth can be complicated by
various factors. For example, sample 10 (taken near the river mouth during
an intense plankton "bloom") does not show high Pb, but sample 12 (from out-
side the "bloom") does. The overall average Pb concentration of these north-
west Gulf of Mexico samples is also higher than values reported by Martin and
Knauer (17) from Monterey Bay, also suggesting Pb contamination in some near-
shore phytoplankton.
Zooplankton trace metal concentrations show no pattern that would indi-
cate an adverse effect from the Mississippi River (Table 4), but, as with
phytoplankton, it is necessary to consider some of the factors that can com-
plicate the gross distribution pattern. Three samples collected offshore
from Corpus Christi were enriched in Pb, Cd, and Cu, compared to samples from
the immediate Mississippi River Delta area and those from offshore Louisiana.
The samples from Corpus Christi were predominantly copepods (unlike most of
the other samples) but does not explain all of their metal enrichment because
one sample from near the Mississippi River had a high copepod component, but
low trace metals. Likewise, clay contamination can explain some, but not all
of the enrichment. Data on 74 additional zooplankton samples from South Texas
analyzed in our laboratory (13 and unpublished data) show large variations in
most trace metals, but generally higher Pb, Cd, and Cu concentrations than in
66
-------
10
§ 20
-C
f 30
c
0)
E 40
0)
CO
50
60
Fe/AI 0.3 0.6 Pb/Alx 10 2
% 4 8 Ppm 20
• i ' rs~" i !j| ra— > i
c
: <
-
-
^
-
-
/ t "
' /<
\
1 >
1
1
.
1
\
\
\
1
1
i :
1 "
Fe Fe/AI Al -
- 1 I.I.I ,
1 I r
4 Cu/Alxl0'42 4 6
40 PPm 10 20 30
i 5I~!
1972- 4 i
> > '
1963
1950- f
1
i
1940 4 '
I
1
1
i
i
1
1920— i i
1 1
1900-^ *
Pb/AI Pb
1
— > J '
/:
i i
i.i • '
\ } -
; | 1
t <
•
• •
-
-
-
-
•
-
Cu/AI Cu "
i i i
Metal/AlxlO"^ 10
50
—3—
20
100
30
150
4
20
8
40
0.08 0.16
04 0.8
10
20
I 30
TJ
I 40
xi
CO
50
60
i
i
Zn/AI
Zn
_l 1_
J I
• '
'• Co/AI Co
-- Cd/AI
J i L
Figure 4. Vertical metal profiles for Station 16 sediment (water depth
110m) . Dates based on Pb-210 cjeochronologies C20) .
67
-------
TABLE 3. HEAVY METAL DISTRIBUTION IN SARGASSUM AND MIXED PHYTOPLANKTON FROM THE NORTHWEST
GOLF OF MEXICO AND MISSISSIPPI DELTA
CD
(Concentrations in vg/g Dry Weight)
Location Al As Cd
la 13,450 5.1
8 6,431 47.0
9 6,396 52.0
0 1,072 5.5
1 3,036
2 3,894
4 1,364 2.9
7b 33 82 . 0
8b 903 40.0
1.1
1.8
1.5
4.3
0.2
1.4
<0.05
1.7
4.6
Co
4.0
4.0
6.6
< 0.5
1.0
2.5
1.8
0.9
4.1
Cu
6.2
11.0
25.2
5.1
6.6
6.0
1.2
5.1
10.6
Fe
7,550
3,514
5,886
1,094
2,887
3,115
1,277
61
685
Pb
20.1
12.9
21.3
5.8
29.0
13.7
2.5
9.1
39.2
Mn
181
77.2
135
19.4
115
80.9
21.2
4.5
21.4
Ni
7.9
4.8
1.1
0.9
4.8
11.0
4.5
15.6
2.6
Zn
40
74
129
55
22
52
13
34
87
Source: Sims, 1975
Median of 1Q samples from Corpus Christi Bay
DSargassum
-------
TABLE 4. HEAVY METAL DISTRIBUTION IN MIXED ZOOPLANKTON FROM THE NORTHWEST GULF OF MEXICO
AND THE MISSISSIPPI DELTA
(Concentrations in yg/g dry weight)
Location Al As Cd Co
2
3
4
6
7
8
9
10
11
12
14
15
16
17
1,252
4,266
500
75
103
340
225
314
266
426
6,000
4,620
51
44
7.6
6.9
7.3
-
5.8
12.0
4.9
1.9
9.0
3.9
6.5
6.4
23.1
29.5
2.4
4.4
4.4
2.9
1.9
1.5
1.0
2.9
0.9
2.4
1.2
2.6
0.4
2.5
0.9
1.5
2.0
2.1
< 0.5
< 0.5
< 0.5
< 0.5
< 0.5
1.1
< 0.5
0.8
< 0.5
0.7
Cu
74.0
23.1
25.6
8.9
7.5
8.2
4.3
6.1
8.6
6.5
3.5
6.6
35.3
9.2
Fe
799
3,663
977
77
122
305
270
397
300
532
4,035
4,760
62
237
Pb
15.3
62.5
16.5
8.5
1.2
2.3
6.2
2.5
< 0.5
< 0.5
5.1
8.3
3.0
7.4
Mn
12.6
105
21.8
7.5
13.7
9.2
10.3
16.3
8.4
28.0
114
70.4
4.7
7.7
Ni
2.0
6.1
2.9
7.8
2.8
2.7
1.0
1.4
8.2
3.5
7.4
6.6
< 0.5
1.4
Zn
155
200
133
135
86
75
41
139
107
116
52
68
49
57
Source: Sims, 1975
-------
the Mississippi River Delta samples. Further, the values are not greatly
different from values given by Martin and Knauer (17). Thus the river does
not appear to grossly contaminate zooplankton, but taxonomy as well as loca-
tion must be considered before a judgment can be made.
Productivity in the delta area is high (450g C/cm2/yr) (El-Sayed, per-
sonal communication), but the distribution of species, grazing rate, and fate
of the produced carbon are not well known. In the open sea, most organic
carbon is destroyed before it is buried in the sediments (18, and references
therein). Such destruction also seems to be true here (despite the shallow
water), because our unpublished data from more than 20 cores in the area show
the organic carbon content of the sediments (^0.5% organic C) to be similar
to that of the river-suspended matter. Low organic C would be expected near
and to the west of the delta even if all of it survived to be buried. The
detrital sediment there is accumulating at rates of 5 g/cm2/yr or faster, and
effectively dilutes the 0.045gC/cm2/yr being produced. The sedimentation rate
drops very rapidly to 0.5g/cm2/yr or less outside the 100m isobath and to the
east of the delta? yet the organic carbon percentage in the sediments goes up
only slightly. Obviously, little of the carbon is bting buriad. By similar
reasoning, plankton are responsible for little trace metal enrichment of the
sediments. These sediments are relatively constant in composition over an
area of measured or implied high variation in detrital sedimentation rate.
Nearshore sediments provide both the major sink for the riverine metal
flux and a historical rteord of matal input. To tract the hintory of metal
input to the Mississippi Delta tht Pb210, we applied dating method to some
of the cores (20), thus allowing dates to ba assigned to the vertical sedi-
ment metal profiles. Metal concentrations are shown normalized to Al to
correct for changes in CaCC>3, salt content, and mineralogy. This can also
be done by normalising to Pe as demonstrated by Trefry and Prasley (23).
Pig. 4 for mid-delta station 16 (Pig. 2) shows that there has been a
relatively homogeneous flux of Pe, Al, Cu, Zn, Ni, and Co to these sediments
over the past 75 years. Pb concentrations, however, have increased by 65
per cent during this time interval, the major onset occurring since the mid-
1940' s (a period of increased usage of leaded gasoline). Surface sediment Pb
concentrations (^45ppm, salt-free, CaCC>2~free) at Station 16 are comparable to
those of prasent-day river particulars (46ppm). In addtion to Pb, surface
sediment Cd concentrations are also high, (double their pre-1950 values).
Moreover, the 1950 0.4ppm Cd baseline concentration is still in excess of
values found in deeper sediments from the delta. Mid-delta Stations 14 and
11B (Fig. 2) had metal distribution similar to that in Station 16.
Rapidly accumulating sediments (>3g/cm2-y) near the river mouth area of
the delta also have relatively straight vertical metal profiles (Pig. 5) .
However, Pb and Cd concentrations, 70 and 200 per cent, respectively, above
base values found at Station 16, are in good agreement with river particulate
concentrations. Uniform Pb and Cd concentrations of 40ppm and Ippm, respec-
tively, for 50-to 60-cm profiles in this area can only indicate that the
pollutant levels have been relatively constant during the past 10 to 15 years.
70
-------
10
E
o
20
a
a>
•o
30
40
50
Fe/AI 0.3 0.6 Pb/Alxl0'44 8 Cu/AlxlO"4 2 4 6
% 4 8 ppm 20 40 ppm |Q 20 30
' I '< (
.
i
-
0 ^
1
• \
1
1
1
1
1
\
\
I {
1
Fe Fe/AI Al
1 II 1
. , 7^.
; (fl
i J
i i
i
i
i
i
i
\ \ J
1962?^ *
Pb/AI Rb
i 1 i I i
1 ' f ' '/'
/ '
1
1
1
I
1
1
•
i
i
1
1 J
J
_„
-
Cu/AI ClJ
1__L___I i 1 _J___J I^_I
Metal/AlxlO'4 10 20 30
ppm 50 100 150
10
20
0)
•o
£ 30
0)
E
1 40
v>
50
i
Zn/AI
I......L...-I
100 200
400 800
T
I
Mn/AI Mn
O.I
0.2
2
F
1
Cd Ccl/AI
1 — I
Figure 5. Vertical metal profiles for Station 9 sediment
(water depth 50m),.
71
-------
Fe/AI 0.3 0.6 Pb/AlxlO"4 2 4
% 2 4 6 8 ppm 10 20 30 40
Cu/AlxlO~2 4 6
10 20 30
E
o
0)
E
I
10
20
30
40
50
Fe
^
V
Fe/AI
1600?
Pb/AI
Cu -
"4
Metal/AlxlO"*IO 20
ppm 50 100
E I0
o
0)
T3
1 30
E
co 40
50 -
4
20
8
40
4
i
I
Zn/AI
' - i
NI/AI
2
10
~"—*T—
4
20
4000 8000
Co/AI
Co -Mn
Figure 6. Vertical metal profiles for Station 15 sediment (.water
depth 550m) , Dates based on Pb-210 geochronolo'gies (20) .
72
-------
Outer delta sediments from Station 15 and Station 11A (Fig. 2), where
accumulation rates are on the order of 0.1 g/cm^-y, also have relatively con-
stant Fe, Al, Cu, Zn, Ni, and Co concentrations, or at least uniform metal/Al
ratios (Fig. 6). High surface Mn concentrations result from a geochemical
redistribution of Mn in the sediment column, rather than a time-dependent
supply. Pb concentrations at Station 15 (Fig. 6) decrease from 43ppm (salt-
free, CaC03~free) at the surface to 20 to 25ppm in the lower core section.
The time scale for this sample, however, permits an extension of the histori-
cal record which shows the onset of pollutant Pb to have occurred about 1840.
This initial flux is followed by the previously observed period of increase
during the mid-1940's and is consistent with Pb profiles for Lake Michigan
sediments presented by Edgington and Robbins (5) who attribute excess Pb
deposited prior to 1920 to inputs from the combustion of coal.
Despite the uniformity of Cu, Ni, and Mn profiles in nearshore sediments,
the absolute values (and metal/Al ratios) are 20 to 40 per cent lower than
those for river particulates. Interstitial water Mn gradients support losses
of Mn to the overlying seawater by reduction-diffusion. We do not have pore
water data for the other metals, but merely point out the possibility that
some of the metal deposited in rapidly accumulating, anaerobic sediment may be
subsequently returned to the overlying water or the surface-most layers of
sediment. This would increase, of course, the availability of these metals
to the benthic community.
In summary, we find very low levels of dissolved trace metals in
Mississippi River water and no evidence of Fe, Mn, Cu, Co, Ni, or Cr pollu-
tion in the River or Delta. However, there are strong indications of anthro-
pogenic inputs of particulate phase Pb, Cd, and Zn. The sedimentary record
shows a 60 per cent increase in Pb and a 100 to 200 per cent increase in Cd
over the past century; and present-day river particulates are greatly enriched
in Pb, Cd, and Zn. Most of the particulate matter settles out very quickly
upon entering the ocean; thus only a small percentage (<1%) of the Gulf of
Mexico has Pb- and Cd-contamination sediments.
73
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REFERENCES
1. Brewer, P. G. 1975. Minor Elements in Sea Water. In: Chemical
Oceanography, Vol. 1, (eds. J. P. Riley and G. Skirrow), Academic
pp. 415-496.
2. Brooks, J. M. 1976. The Flux of Light Hydrocarbons into the Gulf of
Mexico via Runoff. In: Marine Pollutant Transfer, (eds. H. L.
Windom and R. A. Duce), D. C. Heath and Company, Lexington,
Massachusetts, pp. 185-200.
3. Curtis, W. F., J. K. Culbertson, and E. B. Chase. 1973. Fluvial Sedi-
ment Discharge to the Ocean from the Conterminous United States.
U. S. Geol. Surv. Circ. 670, 17 pp.
4. Dyrssen, D., C. Patterson, J. Ui, and G. F. Weichart. 1972. Inorganic
Chemicals. In: A Guide to Marine Pollution, (ed. E. D. Goldberg),
Gordon and Breach Sci. Pub. pp. 41-58.
5. Edgington, D. N., and J. A. Robbins. 1976. Records of Lead Deposition
in Lake Michigan Sediments Since 1800. Environ. Sci. Technol. 10,
266-273.
6. El-Sayed, S. Z. 1975. Texas A&M University, personal communication.
7. EPA Ocean-dumping Criteria. 1973. Federal Register 38, 12872-12877.
8. Everett, D. E. 1971. Hydrologic and Quality Characteristics of the
Lower Mississippi River. Louisiana Dept. Public Works U. S. Geol.
Survey. 48 pp.
9. Garrels, R. M., and F. T. Mackenzie. 1971. Evolution of Sedimentary
Rocks, W. W. Norton. 397 pp.
10. Giam, C. S., H. S. Chan, and G. S. Neff. 1976. Concentrations and Fluxes
of Phthalates, DDTs, and PCBs to the Gulf of Mexico. In: Marine
Pollutant Transfer, (eds. H. L. Windom and R. A. Duce), D. C. Heath
and Company, Lexington, Massachusetts, pp. 375-386.
11. Goldberg, E. D. 1957. Biogeochemistry of Trace Metals. In: Treatise on
Marine Ecology and Paleoecology, Vol. I, (ed. J. W. Hedgpeth), Geol.
Soc. Am. Mem. 67, Washington, D. C. pp. 345-358.
12. Goldberg, E. D. 1965. Minor Elements in Sea Water. In: Chemical Oceano-
graphy, Vol. 1, (eds. J. P. Riley and G. Skirrow), Academic.
pp. 163-196.
74
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13. Horowitz, A., and B. J. Presley. 1976. Trace Metal Concentrations and
Partitioning in Zooplankton, Neuston, and Benthos from the South Texas
Outer Continental Shelf. Arch. Environ. Pollut. Tixcol. (in press).
14. I.D.O.E. 1972. Baseline Studies of Pollutants in the Marine Environ-
ment. Natl. Sci. Found., Washington, D. C. 799 pp.
15. Iseri, K. T., and W. B. Langbein. 1974. Large Rivers of the United
States. U. S. Geol. Surv. Circ. 686, 10 pp.
16. Leifeste, D. K. 1974. Dissolved-solids Discharge to the Oceans from
the Conterminous United States. U. S. Geol. Surv. Circ. 685, 8 pp.
17- Martin, J. H., and G. A. Knauer. 1973. The Elemental Composition of
Plankton. Geochim. Cosmochim. Acta 37, 1639-1653.
18. Menzel, D. W. 1974. Primary Productivity, Dissolved and Particulate
Organic Matter, and the Sites of Oxidation of Organic Matter. In:
The Sea, Vol. 5, (ed. E. D. Goldberg), Wiley-Interscience. pp. 659-
678.
19. National Academy of Science. 1975. Assessing Potential Ocean Pollu-
tants. NAS, Washington, D. C. 438 pp.
20. Shokes, R. F. 1976. Rate-dependent Distributions of Lead-210 and
Interstitial Sulfate in Sediments of the Mississippi River Delta.
Tec. Rep. 76-1-T, Department of Oceanography, Texas ASM University,
122 p.
21. Sims, R. R., Jr. 1975. Selected Chemistry of Primary Producers, Pri-
mary Consumers and Suspended Matter from Corpus Christi Bay and the
Northwest Gulf of Mexico. M. S. Thesis, Texas A&M University, College
Station, 65 pp.
22. Taylor, S. R. 1964. Abundance of Chemical Elements in the Continental
Crust: A New Table. Geochim. Cosmochim. Acta 28, 1273-1285.
23. Trefry, J. H., and B. J. Presley. Heavy Metals in Sediments from
San Antonio Bay and the Northwest Gulf of Mexico. Environ. Geol.,
Vol. 1, pp. 283-294.
24. Turekian, K. K. 1969. The Oceans, Streams and Atmosphere. In: Handbook
of Geochemistry Vol. I, (ed. K. H. Wedepoh), Springer-Verlag, Berlin.
pp. 297-323.
25. U.S. Army Corps of Engineers. 1950-1975. Stages and Discharges of the
. Mississippi River and Tributaries and Other Watersheds in the New
Orleans District. U. S. Army Corps of Engineers, New Orleans.
26. Vinogradov, A. P. 1953. The Elementary Chemical Composition of Marine
Organisms. Sears Found, for Mar. Res., Yale Univ., New Haven, Connec-
ticut. 647 pp.
75
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OIL PRODUCTS IN SURFACE LAYERS OF THE PACIFIC AND INDIAN OCEANS
M. Nesterova, I. Nemirovskaya, N. Anufrieva,
and V. Maslov
Oceanological Institute of the U.S.S.R. Academy of Sciences
Among the many aspects of ecological problems of environmental protect-
ion, one of the most significant is protection of oceans against pollution by
oil products. Oil becomes one of the most widespread pollutants of the
world's oceans. It is enough to mention that oil products were present in 50
per cent of all samples taken at 1587 stations in different regions of the
Pacific and Indian Oceans on research vessels of the Institute of Oceanology
of the U.S.S.R. Academy of Sciences. Observations of ocean pollution have been
carried out here since 1973. Starting in 1975, research vessels and the ana-
lytical laboratory of the Institute began an international project on ocean
pollution observations within the framework of OGSOS. The system of oceanic
stations in the Pacific and Indian oceans is shown in Fig. 1. It was dis-
covered that even in the places where there is no oil film on the surface of
the water or on the surface of buoys, the S-W part of the Pacific Ocean was
covered by small oil-tar balls. In the Indian Ocean, oil products in surface
layers were discovered on two of four polygons, and oil-tar balls were
present in three others. Data, obtained from the sensor for remote sensing
of oil film on the ocean surface (a device developed in the Institute of
Oceanology), are very representative: 315 of 3500 miles of the vessel's run
in the NW part of the Pacific Ocean were covered with oil film. This
'finding confirms that the hazard of toxic pollution of ocean waters is
real.
Pollution of the seas and oceans by oil products results mainly from dis-
charge by tankers in the ocean of oil-containing (ballast and cleaning) water.
Fields of pollutants are observed along the main routes of oil transportation
in the seas and oceans. We have no reason to suppose that drainage of oil-
containing water from tankers will decrease in the future because the volume
of oil transportation increases every year: in 19734 it was 84 million tons;
1949, 151 million tons; 1958, 369 million tons; and, 1968, 1130 million tons.
Today the volume of oil transportation is about 2400 million tons. The in-
crease in oil transportation is caused by wide development of oil-based
technology. About 40 per cent of the world' s energy is obtained from oil and
oil products (1).
The losses of oil in the seas and oceans during transportation amount Cat
present) to 2 million tons per year. Presuming that the present technical
level of methods and means of prevention of sea pollution by oil remains at
the same level, the discharge of oil from tankers into seawaters will reach
the figure of 6 million tons per year by the end of this century.
76
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Tuxuu OHean
Figure 1. The system of oceanic tracking stations is shown in the Indian
Ocean (left) and in the Pacific Ocean (right).
Figure 2,
Structured formations, sometimes used by hydrobionts as carriers,
were found in surface waters.
77
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Oil pollution of, the world's oceans is also up because of the increase in
oil production on the continental shelf. In 1970 the volume of oil produced
on the shelf was 440 million tons, i.e. one-sixth of the total volume of oil
produced. In 1980 it will be 1300 million tons, i.e. one-third of the total
volume of oil production planned. Oil leaks happen during oil production in
underwater oil fields. It is enough to recall the oil leak in Southern
California (Santa Barbara region), which resulted in the mass death of fish
and marine organisms.
Damage in oil fields and on tankers are most hazardous as they have
extreme influence on ecological systems of separate regions of the world's
oceans. We shall mention one more "catastrophy" of the century, the catas-
trophy of theTorrey Canyon, which has shown the danger impending for whole
regions of the planet and the lack of means to avoid such a hazard. Poten-
tially, such hazards always exist due to the increase of tonnage and speed of
tankers. Nineteen tankers sank in 1976, with two times more tonnage than
those which sank in 1975. Five tankers sank in two weeks (15 to 31 December)
near the coast of the U.S. During eight months of 1976, the amount of oil
discharged was 198277 tons. About 20 to 30 per cent of the total pollution
in the seas is caused by oil.
Oil-containing industrial and municipal waste waters, carried to the seas
by rivers, are also an antropogenie source of pollution. Ths total amount of
oil and ©il-produet pollution of the world's oceans, according to various
authors, is estimated to be £rom six to ten million tons per year. It is
obvious that the ocaan cannot eope with such intensive pollution. The pres-
ence of oil products in ocean waters confirms the theory that processes of
ocean pollution prevail over processes of the pollutant's chemical and bio-
logical decomposition.
Oil spilled in the sea produces a film on the surface due to the influ-
ence of waves and wind, When there is a great amount of oil, it mixes with
water producing an emulsion. Thtse are mainly of reverse type "water in oil,"
such as high-molecular substances (resins, asphaltens, etc.). Also present in
oil are emulsion stabilizers of various types.
Such structured formations may exist for a long time in surface waters
and may be carried by currents over long distances. Some hydrobionts use them
as carriers (see Pig. 2). When the density of such formations becomes higher
than the density of water, they sink to the bottom, causing considerable harm
to benthos organisms.
Low-molecular oil compounds evaporate quite rapidly on the surface of the
ocean and have low solubility in seawater. One must take into consideration
here that solubility of hydrocarbons in seawater is lower than in fresh water
(2).
It is natural that pollution of the world's oceans influences physical,
chemical, and biological processes. The presence of oil film on the surface
breaks the exchange of energy, gases, and moisture of oceans and atmosphere.
One must also remember that one-half of the oxygen of our planet is produced
by the ocean. Heat energy of the ocean is one of the important factors
78
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of climate formation. The presence of oil film on the surface of the ocean
might influence weather conditions, but this has not been studied yet and
needs further detailed investigation. By experiments, we determined that one
square mile of ocean evaporates 97 tons of water per hour. When oil film is
present, the amount is only 48 tons per hour.
It is not necessary to mention the fact of the fatal influence of oil on
hydrobionts.
All the above mentioned facts were determined by investigations of pollu-
tion of the world's oceans in the Institute of Oceanology. They included
development of methods and means of protection of the sea from pollution by
oil and measurement of pollution levels (3,4).
At present it is impossible to determine accurately and quantitatively
the oil pollution of seas and oceans. This is caused not only by analytical
difficulties in determining oil products in seawater, but also by not having
sufficient comprehension of all processes which influence oil products in the
seas and oceans. Analytical difficulties are caused by the fact that oil
products are a very complex mixture of different compounds. The quantita-
tive content in oil depends on the oil field. Oil product output also depends
on the process of refining. At the same time, these compounds are very close
to some natural compounds present in seawater as a result of the activity of
marine organisms. Absence of a unified methodology of determination of oil
hydrocarbons does not permit the possibility of comparing the results of
different investigations and drawing conclusions on changes in pollution of
certain regions of the world's oceans. This is especially the case when it
is necessary to determine the results of measurements of prevention of sea
and ocean pollution by oil and oil products.
When conducting an international experimental project of studying oil
pollution of the marine environment, two methods, fluorescent and IR-spee-
trohotometry, are used. The fluorescent method is the most sensitive. But
when using this method for determination of oil products in seawater, one
should take into consideration that fluorescence of oil depends on many
aspects (composition, transformation of substance under the influence of
environment, wave length X exitation, X registration, and so on), which makes
it very difficult to compare the results obtained. In our tests we studied
spectra of exitation and spectra of fluorescence of oil products and crude
oils from different oil fields of the USSR, Iran, and Vietnam. The first
data obtained give us a method to assess the presence of hydrocarbons in the
waters of the Pacific and Indian Oceans.
Measurements of hydrocarbons in ocean waters were performed by IR-spec-
trophotometry.
The study was conducted during the 12th and 13th cruises of the Dmitri_
Mendellev, and the 56th cruise of the Vitiaz_ in the Pacific Ocean, Sea of
Japan, and Okhotsk Sea. Three hundred and twenty samples were taken during
six tests in the Pacific Ocean and Sea of Japan, In the open areas of the
Pacific Ocean and Sea of Japan, hydrocarbons were not detected. This can be
explained by the fact that in the warm part of the year, when studies were
79
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conducted, decomposition of non-polar hydrocarbons is most intensive (5) .
There were some exclusions , for example when content of hydrocarbons in the
samples amounted to 60-80 mg/£. These local contaminations are possibly the
result of the discharge of cleaning water from tankers. Hydrocarbons were
found in the island (up to 3900 g/£) , and in the zone of intense navigation,
Sangar Strait (130 to 150 g/&) . Only two of 40 samples taken in Okhotsk Sea
showed the presence of hydrocarbons (50
Studies in the Pacific Ocean were continued in the 14th to 16th cruises
of Dm. Mendel lev (Feb. to May and July to Sept. 1975, Dec. 1975 to March 1976)
and~Tn the 59th cruise of the Vitiaz from May to June 1976.
Hydrocarbons were found in surface waters of the SE part of the Pacific
Ocean, mainly in equatorial zone (30°NL to 20°SL) , where their concentration
differed from 50 to 1460 g/H. i Hydrocarbon content in all samples from the
Western tropical zone of the Pacific Ocean were from 90 to 380 g/H. On the
polygon, in the NW part of the Pacific Ocean (39°NL to 34.5°NL; 146.9° to
150°EL) , hydrocarbons were only found in 24 samples (in concentrations of
80 to 340 g/£) .
In the Sea of Japan and the NW part of the Pacific Ocean, the concentra-
tion of hydrocarbons changed from 0 to 380 g/H. In the 63 of 123 samples,
hydrocarbons were not present. In the southern part of the Sea of Japan in the
region of Honshu Island and in Sangar Strait, hydrocarbons are present in con-
centrations of 240 to 280
The biggest concentration of hydrocarbons in the SE part of the Pacific
Ocean was detected in port areas of Singapore, 7060 g/&, Freemantle, 1040 g/&,
and in the seaways near western Australia in the region of lawa Island,
1000 g/£. In the Fiji and Tasman Seas, hydrocarbons were seldom found.
Practically no data are available concerning distribution of tar balls in
the Pacific Ocean. Investigators (5) have shown that the range of concentra-
tions of tar balls in the NW part of tne Pacific Ocean lies in the limits of
0.3-14 mg/m^ to 0-2.9 mg/m^, in the NE part. Maximum concentrations are found
in Kurosivo Stream.
It is natural that we cannot draw the conclusion based on the small num-
ber of measurements taken, that the western part of the Pacific Ocean is more
polluted than the eastern part, as the distribution of tar balls is not stable
and is non-uniform.
In January to March 1974, studies of the equatorial part of Indian Ocean
were conducted on board r/v Vitiaz . Samples were taken on four polygons
85°EL, 75°EL, 65°EL, 54°EL, sections from 4°SL to 4°NL. Hydrocarbons were
found on the first and the second polygon, i.e. in the eastern part of the
region. The maximum concentration of 1130 g/Jl was found on the first poly-
gon. We found a general tendency of some non-uniform decrease in the con-
centration of hydrocarbons with depth, excluding two stations on the second
polygon (0°55'S, 74°49'E), where the concentration in the surface layer was
equal to 160 g/H. At 100 m it increased to 240 g/H and at 200 m was 850 g/k.
In the western part of the equatorial zone of the Indian Ocean, hydrocarbons
80
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were not found in surface waters, but tar balls were present. Relatively high
hydrocarbon contents in the eastern part of this region, which lays far from
ship lanes, may be explained by hydrodynamic conditions of this part of the
ocean (the zone of surface streams). In winter, this region is the area of
the southern periphery of the western monsoon stream, and the northern part
of the equatorial counter stream. The velocity of monsoon stream increases
from the east to the west (from 40 to 120 cm/sec). The hydrocarbons are
probably transported from the dynamically active western zone and are accumu-
lated in the relatively calm eastern zone.
The NW part of the Indian Ocean was studied in March to June of 1976 by
r/v Academician Kurchatov in five sections; along the African coastline, a
quasizonal section along 8°SL, a meridianal section along 65° to 67°EL, and
two small sections on the Oman and Aden Gulfs.
The concentration of hydrocarbons in the surface layers of Bab-al-Mandeb
Strait, and along the African coast, changed from 0 to 350 g/&. In 42 per
cent of the samples, hydrocarbons were not detected. On the longitudinal
section, hydrocarbons were absent in 2 of the 16 samples. The concentration
in samples taken near Madagascar reaches the value of 80 to 320 g/&. Determi-
nation of oil-oxidizing bacteria corresponds with the data on hydrocarbon
concentration. On the section Sokotra to Mombasa, bacteria were not present
in the surface layer. The maximum bacteria concentration was found in the
region of the Port of Mombasa (200 to 300 g/&). On the latitudinal section,
oil-oxidizing bacteria was found near the northern part of Madagascar.
On the meridional section we found a non-uniform increase in the concen-
tration of hydrocarbons in a northerly direction. In the southern part of the
section (in the region of the South Subtropic convergence), hydrocarbons were
not found. From 15OSL, we found an increase of hydrocarbon concentrations
from 14° to 2°SL. In the region of the equator, the concentration is equal
to 130 g/fc.
From 11° to 18°NL hydrocarbons were not found, but then they appeared in
concentrations of up to 2870 g/&. This change of concentration corresponds to
the dynamics of the region. The southern part of the Arabian Sea is very
active dynamically.
In the Oman and Persian Gulfs, the concentration of hydrocarbons reached
1000 g/&. The maximum concentration was found in the region of El-Kuwait,
and in the Oman Gulf. The quantity of hydrocarbons decreases slightly with
depth. In the Persian Gulf, a large concentration of hydrocarbons corresponded
to the maximum quantity of oil-oxidizing bacteria. In Aden Bay, the quantity
of hydrocarbons was also rather large. The maximum content of hydrocarbons
was found near the coast of the Arabian Peninsula, and in the central area
the content decreased to 420 g/&. Approaching the African coast, we found
some increase but did not notice a decrease of the concentration with depth.
We think that the waters near the Arabian Peninsula are of Persian-Arabian
origin, which explains the presence of hydrocarbons. In March 1976, hydro-
carbons were found in 11 of 17 samples in concentrations not more than
300 g/&. In June 1976, hydrocarbons were found in 13 of 16 samples in con-
centrations from 0 to 2260 g/&. In March, 1976, oil spots in the Red Sea
81
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were seen only once Cin June). An oil-film of yellow-green, brown, and grey
color covered a considerable part of the surface of the sea.
Thus, the studies of surface waters for hydrocarbons show the presence
of hydrocarbons in the Pacific and Indian Oceans. The concentration of hydro-
carbons depends on the anthropogenic, hydrodynamic, hydrobiological, and other
factors. The studies should be continued. The prognosis of seawater quality
may be done only on the basis of systematic, complex studies of seawater
pollution. Under these conditions, recommendations on the protection of the
world's oceans can be prepared.
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REFERENCES
1. Nunuporv, S.M. 1971. Prevention of Marine Oil Pollution. Transport,
Moscow,
2, Goldberg, E.D. 1975. Health of the Oceans. USA.
3. Nesterova, M.P. 1972. Prevention of Marine Oil Pollution When Cleaning
Tankers.
4. Nesterova, M.P. 1976. Surface Radioactive Substances and Their Role
in Solving Several Marine Ecology Problems. Proceedings of the
International Symposium on Substances Contained in Water-Toxic Sub-
stances in the Baltic Sea. Rostok GDR.
5. Nelson-Smit. 1973. Marine Oil Pollution. GIDROMETIZDAT, Leningrad.
83
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OIL POLLUTION STUDIES IN THE NORWEGIAN AND GREENLAND SEAS
V. M. Smagin and'V. S. Rachkov
The Arctic and Antarctic Research Institute, Leningrad
Oil pollution of the world's oceans has become the subject of special
concern to various national and international research organizations within
the International Pilot Project on Marine Pollution Monitoring. This project
envisages study of water surface contamination by petroleum products of the
North Atlantic, the Norwegian and Barents seas, thus providing us with a
possibility to study processes of pollutant transport, including a current
system from the Atlantic to the Arctic Ocean. The need for such a study seems
to be quite obvious. Once oil has entered the high latitude seas it would
accumulate there due to slow degradation processes at low temperatures. An
oil spill on the Arctic ice could significantly change the radiational balance
of the underlying surface as a result of sharp decrease in ice albedo which in
turn could cause considerable climatic effects on the whole region.
Before handling the problem of oil pollution in the observed region/ it is
necessary to outline briefly some features of its hydrometeorological regime.
The hydrometeorological regime of the Norwegian and the Greeland seas is
rather complex. It has large seasonal variations and it is affected by the
following main factors:
1) influence of the warm Atlantic waters from the south.
2) influence of the cold Arctic waters from the north.
3) presence of the Norwegian and Greenland water gyrals inducing the
upwelling of the bottom water masses.
4) presence of stable and seasonal (winter) hydrofronts.
5) effects of the Icelandic Low and the Arctic High.
A complex hydrological regime, and its seasonal variability, determine
the character of the hydrochemical water regime of the region. Oceanic and
atmospheric processes appear to also affect the conditions of pollution
fields, their spatial and time variations.
During the period of 1975 to 1977, the Arctic and Antarctic Research
Institute (AARI) carried out a series of oil pollution studies of the surface
waters in the North Atlantic, the Norwegian and Greenland Seas. The analysis
of oil samples was performed by the infra-red spectrophotometry method with
only dissolved and emulsified hydrocarbons being defined. Sample filtration,
however, to avoid microscopic tar balls, was not made. Sample of 2H marine
water samples was made at 1 m depth in accordance with the recommendations of
the IOC/WMO Pilot Project on Marine Pollution Monitoring. During sampling,
84
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care was taken to avoid contamination of seawater samples by petroleum films.
The hydrocarbon extraction was made at the ship laboratory by 0014. The
extracts were placed into glass flasks with tight stoppers under a 1-cm water
layer. The solvent and the flasks were prepared at the laboratory and
thoroughly tested. The final analysis by infra-red spectrophotometer was
also performed at the AARI laboratory.
Sampling for tar balls was made by Neuston net towed by a ship according
to IOC/WMO Pilot Project recommendations.
The data obtained on petroleum hydrocarbons, or to be more exact, on
non-polar hydrocarbons, in the surface waters of the North Atlantic, the
Norwegian and Greenland Seas during the 1975-1977 period, refer to different
seasons. Unfortunately it was not possible to carry out studies during all
seasons of the year which implies certain difficulties with data comparison.
Most of the data was obtained in the spring. Figure 1 shows hydrocarbon
content observed in the North Atlantic in the spring 1975. In some cases an
increase of the maximum permissible concentration of hydrocarbons was observed,
with concentration in the Atlantic waters then moving to the Norwegian Sea.
The amount was less than 30 Mg/£, (i.e.,below the limit for the sensitivity of
the determination method).
In the spring of 1976, studies of surface water petroleum pollution of
the Norwegian and Greenland seas were made simultaneously from aboard two
AARI research vessels. The observations covered the whole water area of the
Norwegian Sea and the ice-free area of the Greenland Sea (Fig. 2, 3). It is
worth mentioning here that despite the increased hydrocarbon content (more
than 30 yg/£) in some areas, no extensive pollution fields were found in the
region. Even in areas with an increase in hydrocarbon content there was large
non-uniformity in the distribution. In a number of adjacent sampling areas
the hydrocarbon content was either higher or lower than 30yg/&. According to
data obtained in March of 1976 by the r/v Professor Zubov (Fig. 2), the larg-
est density of values exceeding 30 yg/£ was observed in the Greenland Sea in
waters adjacent to the northern coast at a section along the 70° latitude
(i.e.,at the boundary of the Norwegian and Greenland water gyrals). In May,
at the eastern periphery of the Greenland circulation, a patch of oil with a
hydrocarbon level exceeding 60 yg/£ was detected.
Unlike the data obtained by the r/v Professor Zubov, which operated
mainly in the Greenland gyral area, the data obtained in spring of 1976 by
the r/v Professor Viese covered almost the whole water area of the Norwegian
Sea. The observations were sufficiently frequent to allow us to assess the
level of surface water oil pollution (Fig. 3). It turned out that the cen-
tral part of the Norwegian Sea was less contaminated (the regions of the
Norwegian circulation),but at its northern and southern peripheries the
hydrocarbon concentrations were found to exceed 30 yg/£. In the southern
part of the sea the hydrocarbon concentrations were lower than 30yg/&. How-
ever, on several occasions in the Norwegian current, their increase was
observed. Particular attention should be given to the region near the Nor-
wegian coast between 67° and 70°S, where the hydrocarbon content exceeded
85
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30ygA. In the Nordkapp current waters the hydrocarbon content did not exceed
this value.
In the summer of 1976, data from the r/v Professor Viese disclosed the
largest hydrocarbon concentration in surface waters of the Norwegian Sea. The
oil was observed in the southern part in areas adjacent to the North Sea,
Faerbe-Shetland Channel and Paeroe-Iceland Strait (Fig. 4). In the area of
68° to 70°S, near the Norwegian coast, the hydrocarbon concentration remained
large.
In the winter period of 1977 the observations of hydrocarbon content
were carried out on board of the r/v Professor Viese (Fig. 5). The data ob-
tained on this cruise show that in winter, the hydrocarbon concentration did
not exceed 30 yg/fc, with the exception of two stations: one in the Shetland
Islands area (hydrocarbon content - 40 yg/£, the other in the Faeroes Islands
area (hydrocarbon content - 130 yg/£).
During this voyage in the Greenland and Norwegian so.as and also in the
Faeroe-Iceland Strait, surface layer trawling by a Neuston net was performed
to detect tar balls. The analysis indicated that in all samples taken, there
were no tar balls present.
The comparison of 1976-1977 data has shown that in the winter of 1977 the
hydrocarbon content in surface waters of the North-European basin was lower
than that in the summer of 1976. The hydrocarbon content in most samples was
within the limit of the sensitivity of the analysis method. This decrease
cannot be attributed to seasonal variations, nor can we suggest a pollution
decrease trend. It should be noted here that most samples with higher hydro-
carbon content were taken in light winds and small swells except in coastal
areas and at sampling sites in the island area. During winter studies of 1977
optimum conditions for surface water mixing down to a deeper depth were ob-
served. Wind speed in general exceeded 10 m/sec., and the wave height was
about 1.5 m. Therefore, organic substance present in marine water, observed
in light wind and on the sea surface as film, can interfere with hydrocarbon
determination. Therefore, to determine petroleum hydrocarbon content in the
waters of the Norwegian and Greenland seas it is desirable to use methods
more sensitive and selective than infra-red spectrophotometry. That is why
such methods are luminescence spectrometry and gas chromotography are used,
at present. The following conclusions can be drawn from the above:
1) Studies performed by the AARI in 1975-1977 showed the hydrocarbon
content in the surface layer almost over the entire Norwegian and Greenland
seas to be less than 30 yg/Jl.
2) The highest hydrocarbon content was in the surface waters of the
Norwegian circulation in the southern area of the sea and off the Norwegian
coast in the area between 68° and 70°N.
3) The highest hydrocarbon content in the surface waters of the Greenland
sea was found in peripheral areas of the Greenland circulation and waters
adjacent to the northern coast of Iceland.
86
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4) The hydrocarbon level in the North Atlantic current surface waters is
too low to form pollution fields in the region, but the effect of the North
Sea waters in this respect might be decisive.
5) Waters of the Spitsbergen and the Nordkapp current have lower hydro-
carbon concentrations and cannot be considered as a source of oil pollution
of the Arctic basin waters.
10
'&
^ £
¥ -tf
•48
20
Figure 1. North Atlantic hydrocarbon content (yg/£)_ during 4 April to June 6,
1975.
87
-------
figure 2. The hydrocarbon distribution (ygA) at 1 meter depth from 13 March
to 28 May 1976, on the 19th cruise of the R/V Professor Zubov.
88
-------
Figure 3, The hydrocarbon distribution (yg/A) at 1 meter depth in spring
1976, on the 25th cruise of the R/V Professor Viese.
89
-------
Figure 4. The hydrocarbon distribution (jjgA) at 1 meter depth in summer
1976, (17 June to 13 July 1976) on the 25th cruise of the R/V
Professor Viese.
90
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Figure 5. The hydrocarbon distribution (jjg/&) at 1 -meter depth in winter,
1977, (27 December 1976 to 1 March 1977) on the 27th cruise of
the R/V Professor Viese.
91
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STUDY OF METHODS OF SAMPLING SEAWATER FROM THE
OCEAN'S SURFACE MICROLAYER AND RESULTS OF DETERMINATION
OF OIL IN VARIOUS REGIONS OF THE ATLANTIC OCEAN
V.I. Mikhaylov and S.G. Oradovskiy
State Oceanographic Institute, Moscow
Odessa Branch of the State Oceanographic Institute
Odessa
Questions pertaining to the properties of seawater at the ocean-atmo-
sphere interface have been insufficiently studied. This is due to the fact
that it is still unclear what should be regarded as the surface microlayer
and how to estimate its thickness.
According to recent investigations (6,10,12,13,15), the distinctive
character of the chemical composition of the water of the ocean's surface
layer applies only to a thin layer comparable to the electric double layer,
i.e., its thickness does not exceed the diameter of ten water molecules.
Data of experimental studies (4,9,11,14), shows that the distinctive
character of the surface microlayer of seawater extends over thousands of
angstroms or more. Depending on the character of the waves, the thickness of
this microlayer can vary from 5.10~3 to 0.1 cm.
The study of the surface microlayer is hampered in many respects by
the difficulties involved in taking the samples of surface seawater.
According to literature data, only a few methods of sampling of the surface
microlayer are known (1,2,3,5,7,8), but most have certain disadvantages.
A.V. Tsyban (5) has designed a device for taking water samples from the
0-2 cm layer that is used for collecting bacteria. The receiving part of
the device consists of a two-necked 250-cm3 glass ampoule. The ampoule is
lowered in a horizontal position onto the surface of the sea and samples a
thin, 2-cm layer of water.
The same principle underlies the operation of a device proposed by
G.M. Kogan (3) for sampling seawater from the surface microlayer. The
device consists of a flat plexiglas plate measuring 60 x 50 x 10 cm. Foam
plastic strips attached to the edges of the plate keep the device in. a
horizontal position. The lower edge of the device is lowered onto the sur-
face of the water, and while slowly moving forward, it shears off a layer
of the surface water no more than 10 cm thick.
92
-------
A different principle underlies the sampling of seawater by means of a
hose sampler (1). The collector of the device consists of a foam plastic
floater measuring 20 x 20 x 20 cm with a hole in the middle that accommo-
dates a glass tube. The lower end of the tube is placed at a depth of
about 3 cm from the water line of the floater; the upper end is connected
by a rubber hose to a jar. A wide-mouth jar closed with a stopper with
two bent glass tubes serves as the sampler. The lower end of one of the
tubes almost touches the bottom of the jar and is connected by a rubber
hose to a Komovskiy vacuum pump. The pump evacuates the jar, and the
escaping air is replaced by seawater, which comes in from the collector.
By changing the depth of immersion of the glass tube passing through the
floater, seawater can be obtained at a distance of 3 cm or more from the
sea surface.
The "Afrodita-1" device built by V.I. Timoshchuk successfully
embodies the sampling principles developed by G.M. Kogan and V.S. Bol'shakov
(4). Purpose of the device is to sample seawater from a drifting or slowly
traveling ship in a layer extending from the surface to a depth of a few
centimeters. It consists of a collector, pointer, container, vacuum
pump, and vacuum and rubber-canvas hoses. The collector consists of two
foam plastic floaters which, for greater rigidity and stability, are con-
nected by stainless couplings. Fastened between the floaters is a
plexiglas sheet (3 mm thick) with cavities in the shape of funnels ending
in couplings. The funnel couplings are connected by vacuum hoses to a
T joint that is connected to the container by a rubber-canvas hose. Rudders,
which provide for a specified immersion depth of the device and a thickness
of the sampled water layer, from 0 to 20 cm, are attached to the lower
part of the collector. The thickness of the collected layer of seawater
depends on the state of the sea surface, wind velocity, and depth angle of
attack.
A simple arrangement for sampling the surface microlayer of seawater by
means of a screen was proposed by Garrett (8). The sampler consists of a
stainless steel frame over which is stretched a net of the same material.
Handles by means of which the sampler is lowered onto the water surface
are welded to the frame. The device is lowered onto the water surface
from a boat, and after the meshes are filled with water, it is raised.
The water occupying the meshes of the screen is poured through a corner of
the frame into a receiving container. This device permits the sampling
of a surface microlayer of seawater no more than 300 y thick.
Thus, it may be concluded that each of these sampling methods permits
the sampling of different layers of surface water (from 300 y according to
Garrett, and to 10 cm according to Kogan). This makes it impossible to
compare the results of analyses of sea and ocean surface waters sampled
with different instruments and devices.
In our view the sampler proposed by Garrett is currently the most
successful device for sampling water from the layer closest to the ocean-
atmosphere interface. However, the material from which the sampler is made
93
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does not fully meet the requirements for such devices because it is subject
to corrosion, which changes the chemical composition of the seawater sample
and distorts the results of findings.
We tested screen samplers made of various materials, i.e., gauze,
brass, stainless steel, and nylon. We found that the best results were
obtained with nylon. The nylon sampler is based on the principle proposed
by Garrett and uses No. 7 nylon screen (with a mesh area of 1 mm2). The
screen is stretched over a frame of noncorroding material. Four guy ropes
of fish line attached to the frame are connected to a kapron marline longer
than the height of the ship's side.
The sequence of sampling of the surface microlayer by means of this
sampler is as follows. To exclude contaminants from the ship, the sampling
is carried out immediately after the ship has stopped. The sampler is
lowered to the sea surface on the lee side of the forecastle. As soon as
the water fills the openings of the screen, the sampler is quickly raised.
The sampler raising time is 5 to 6 seconds. On board the ship, the sampler
is tilted, and the seawater collected by the meshes is drained into a
receiver (jar).
In the winter of 1975-76 we conducted studies in the central and
northern Atlantic to estimate the thickness of the sampled microlayer with
screen samplers. The work was done under ship laboratory conditions and
directly under natural conditions. During the studies, the wind, velocity
ranged from 2 to 8 rn sec~l, and the wave height, from 0.2 to 2.5 m.
Two samplers with an area of 2460 cm2 and 11079 cm2 were built. Average
results obtained from the determination of the thickness of the sampled
surface microlayer of water with screen samplers of different areas are
presented in Table 1.
Analysis of the results obtained indicates that independently of the
area of the sampler, the thickness of the sampled microlayer is approxi-
mately 230 microns. The variation coefficient for samplers with an area of
2460 cm2 varies from 6.6 to 10%, and for samplers with an area of 11079 cm2,
4.3%.
It should be noted that the studies were carried out in waters of
different salinity (from 29.3% to 37.6%), but this did not affect the thick-
ness of the surface microlayer sampled.
The data of actual measurements of the thickness of the sampled surface
microlayer were confirmed by experiments in the ship's laboratory. A model
of the screen sampler with an area of 100 cm2 was prepared for this purpose.
The experiments were conducted with seawater of different salinity as well
as distilled water. The water temperature varied from 8°C to 26°C. The
results of these studies are presented in Table 2.
Analysis of the data of Table 2 suggests that the screen sampler model
samples surface microlayers whose tnickness is independent of the water
94
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TABLE 1. RESULTS OF DETERMINATION OF THE THICKNESS OF SAMPLED SURFACE MICROLAYER WITH A
SCREEN SAMPLER HAVING A MESH AREA OF 1 mm2
01
Type of sampler
Sampler with
nylon screen
mesh area 1 mm2
S
2460
2460
2460
11079
11079
11079
n
22
22
23
21
24
22
V
54.3
54.4
54.2
247.0
247.0
247.0
S
5.4
5.2
4.6
10.8
10.2
10.1
K
10
9.4
6.6
4.4
4.2
4.2
CI
54.3 ± 4.3
54.4 ± 4.7
54.2 4.3
247.0 13.1
247.0 12.2
247.0 12.2
Z
221
221
221
222
222
222
S 0/00
37,627
37,520
33,827
37,580
33,827
29,342
Symbols:
n - number of determinations
v - average amount of water collected
at one time, cm3
& - rms deviation, cm3
S - area of sampler, cm2
K - variation coefficient, %
CI - confidence interval, cm3
Z - thickness of sampled layer, microns
S °/00 - salinity of sample, °/00
-------
TABLE 2. RESULTS OF DETERMINATION OF THE THICKNESS OF SAMPLED SURFACE MICROLAYER OF SEAWATER
AND DISTILLED WATER USING A MODEL OF SCREEN SAMPLER UNDER LABORATORY CONDITIONS
Type of sampler
Model of sampler
with a mesh area
of 1 mm2
S
100
100
100
100
100
100
n
31
24
21
28
32
37
V
2,0
2,0
2,0
2,0
2,0
2,0
6
0,03
0,04
0,03
0,03
0,04
0,05
K
1,2
1,5
1,4
1,3
1,4
1,5
CI
2,0 0,04
2,0 0,05
2,0 0,04
2,0 0,06
2,0 0,06
2,0 0,06
Z
200
200
200
200
200
200
so/oo
36,980
33,827
36,520
29,342
distillate
distillate
vO
cr>
Symbols:
n - number of determination
v - average amount of water collected
at one time, cm3
8 - rms deviation, cm-3
S - area of sampler, cm2
K - variation coefficient, %
CI - confidence interval, cm^
Z - thickness of sampled layer, microns
S °/00 - salinity of sample, °/00
-------
salinity and temperature and amounts to 220 microns (variation coefficient,
1.2 to 1.6 per cent.)
To determine the effect of various types of surfactants on the thick-
ness of the surface microlayer sampled, a series of experiments were con-
ducted with surfactant additions to water using a screen sampler with a
mesh area of 1 mm2. Different amounts of the preparation "Novost" and
sodium alkyIbenzoylsulfate were added to the water samples to concentrations
of 1000 yg/£~l or higher, which were known to be high in comparison with
detergent concentrations observed in open water areas of the North Atlantic.
The screen sampler model was used to collect samples of these solutions.
Average results of experiments with additions of synthetic surfactants
to seawater and distilled water are given in Table 3.
It is evident from Table 3 that the additions of synthetic surfactants
in amounts up to 2000 yg/£~l to the solution studied did not affect the thick-
ness of the surface microlayer sampled.
The results of the study lead to certain conclusions:
(1) The amount of sampled water, and hence the thickness of the
sampled layer, are independent of the salinity of the water and presence of
detergents.
(2) Independently of its own area, the screen sampler made of a nylon
net with a mesh area of 1 mm^ samples a water layer 220 microns thick with
a variation coefficient of 4.4-10%.
In the winter of 1975-76, water samples were taken from the surface
micro-layer in various regions of the Atlantic Ocean for the purpose of
studying oil pollution. The results of an analysis of these samples by the
"Oil-102" IR analyzer are presented in Table 4.
The highest concentrations of petroleum products in the water of the
surface microlayer were found in the region of the Canary Islands. A little
later they were found in studies in the region of 30°W. For comparison,
let us note that at the 1-m level (the water was collected with Niskin's
plastic sampler), trace amounts of petroleum products were detected, the
maximum of which was only 0.3 mg/£~l.
97
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TABLE 3. RESULTS OF DETERMINATION OF THE THICKNESS OF SAMPLED SURFACE MICROLAYER WITH A
SCREEN SAMPLER MODEL HAVING A MESH AREA OF 1 mm2 FOR WATER WITH ADDITIONS
OF DETERGENTS
Type of sampler
Model of sampler
with a mesh area
of 1 mm2
n
31
38
39
32
47
Type and amount of
detergent added, ug/£
"Novost" - 1000
Sodium alkylbenzoyl-
sulfate - 1000
"Novost" - 1000
Sodium alkylbenzoyl-
sulfate - 100
"Novost" - 2000
S
100
100
100
100
100
V
2.0
2.0
2.0
2.0
2.0
S
0.04
0.05
0.05
0.05
0.05
K
1.6
1.6
1.5
1.5
1.5
CI
2.0=0.05
2.0=0.05
2.0=0.05
2.0=0.05
2.0=0.05
Z
200
200
200
200
200
S°/00
36,980
33,527
distillate
distillate
36,980
oo
Symbols:
n - number of determination
v - average amount of water collected
at one time, cm^
& - rms deviation, cm^
S - area of sampler, cm2
K - variation coefficient, %
CI - confidence interval, cm^
Z - thickness of sampled layer,
microns
S °/QO - salinity of sample, °/00
-------
TABLE 4. COORDINATES OF STATIONS AND RESULTS OF DETERMINATION OF THE
CONTENT OF PETROLEUM PRODUCTS IN THE SURFACE MICROLAYER
OF SEAWATER IN THE WINTER OF 1975-76
Coordinates
(N)
27°37
27°48
28°05
28°14
28°33
2 8° 30
28°58
29°30
29°28
29°10
29°01
31°00
34°00
36°00
38°01
40°00
46°00
50°00
50°00
(W)
026°36
026°38
026°00
025°47
025°52
025°37
026°03
026°20
026°22
026°27
026°28
030°00
030°00
030°00
030°02
030°00
030°03
018°22
010°00
Oil concentration,
mg/£~l
3,80
4,20
2,20
2,40
1,80
3,20
2,80
3,10
1,80
0,70
0,80
0,56
0,45
1,60
1,80
2,00
2,00
2,30
2,65
99
-------
REFERENCES
1. Bol'shakov, V.S. 1968. Comparative Hydrological Characteristics of the
Black, Azov, and Caspian Seas. Ecological Biogeography of Contact Marine
Zones. Naukova Dumka, Kiev, 69 pp.
2. Balashov, A.I., Yu. P. Zaytsev, G.M. Kogan, and V.I. Mikhaylov. 1974.
Study of Certain Components of the Chemical Composition of Water at the
Ocean-atmosphere Boundary. Okeanologiya, Vol. 14, No. 5, pp. 817-821.
3. Kogan, G.M. 1969. Determination of Certain Trace Elements in Black Sea
Water. Problems of Bioceanography. Naukova Dumka, Kiev, 127 pp.
4. Timoshchuk, V.N. 1970. Description of the "Afrodita-1" Device for
Collecting the Neustic Water Layer. Radioecological Studies of the
Mediterranean Sea. Naukova Dumka, Kiev, 87 pp.
5. Roll1, G.U. 1968. Physics of Atmospheric Processes above the Sea.
Gidrometeoizdat, 237 pp.
6. Tsyban1, A.V. 1967. Nature of the Collection of Microbiological Samples
in the Near-surface Microhorizon of the Sea. Gidrobiologicheskiy
zhurnal, Vol. Ill, No. 2, pp. 47-52.
7. Skopintsev, B.A. 1938. Organic Matter in Seawater and Foam of the
Southwestern Region of the Caspian Sea (Oct.-Dec. 1936). DAN SSSR,
Vol. 18, No. 7, pp. 352-358.
8. Garrett, W.D., and W.R. Barber. 1974. Sampling and Determining the
Concentration of Film-forming Organic Constituents of the Air-water
Interface. Naval Research Laboratory Memorandum Report 2852,
Washington, DC pp. 113-115.
9. Kanwisher, J. 1963. On the Exchange of Gases between the Atmosphere
and the Sea. Deep-Sea Res., Vol. 10, 195 pp.
10. Home, R.A. 1972. Structure of Seawater and its Role in Chemical Mass
Transport between the Sea and the Atmosphere. J. Geophys. Res.,
Vol. 77, No. 27, pp. 5171-5176.
11. Harvey, G.W. 1969. Microlayer Collection from the Sea Surface. Limnol.
Oceanographer, Vol. II, pp. 608-613.
100
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12. McAlister, E.D., and W. McLeish. 1969. Heat Transport in the Top
Millimeter of the Ocean. J. Geophys.. Res., Vol. 13, No. 74, pp. 217-
225.
13. Zobell, C.E. 1939. Occurrence and Activity of Bacteria in Marine
Sediments. In: Recent Marine Sediments, P.O. Trask, Ed., Am. Assoc.
Petroleum Geologists, Tulsa, OK, pp. 87-95.
14. Ewing, G.C., and E.D. McAlister. 1960. On the Thermal Boundary Layer
of the Ocean. Science, Vol. 13, No. 131, pp. 169-178.
15. Welander, P. 1959. Coupling between Sea and Air. Proceedings of
Oceanogr. Congress, New York, pp. 67-', 1
101
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CESIUM-137 AS A TRACER FOR REACTIVE POLLUTANTS IN ESTUARINE SEDIMENTS
H.J. Simpson, C.R. Olsen, R. Bopp, P.M. Bower, R.M. Trier, and S.C. Williams
Lament-Doherty Geological Observatory
Palisades, NY 10964
ABSTRACT
Many reactive pollutants discharged to natural
waters become associated with fine-grained particles.
Accumulation and transport patterns of fine particles
in estuaries and other natural water systems can be
quite complex and difficult to predict. Cesium-137,
a fission product with a 30-year half-life, has been
added in readily measureable quantities to natural
waters around the globe as a result of fallout from
atmospheric nuclear weapons testing. Measurement
of Cs-137 in estuarine sediments can be used to
rapidly establish the distribution of recent (last
two decades) fine-grained sediments. In the sedi-
ments of the Hudson River Estuary (USA), the amount
of Cs-137 has been found to correlate with the dis-
tribution of a wide range of reactive pollutants in
sediment depth profiles as well as in surface sedi-
ment concentrations. The pollutants for which we
have found such a covariance with Cs-137 include
Pu-239, 240, PCBs, Zn, Cu, Pb, Cd, and Ni.
INTRODUCTION
A substantial number of the pollutants discharged into natural waters
can be classified as "reactive" in terms of their propensity to be associated
with particles, either in the original effluent or after becoming dispersed
in the receiving water. For example, metals from the electroplating industry
and some types of artificial radionuclides released from nuclear power plants
are transported and accumulated on particles in natural waters, as well as in
solution. The particles most important in reactive pollutant transport are
usually relatively small and often contain both organic and inorganic compo-
nents. We will not discuss the composition or sorption characteristics of
these fine particles, but instead will describe some of their characteristics
as vectors of pollutant dispersal and accumulation.
*Present address: Lederle Laboratory, Pearl River, NY.
102
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In estuaries, fine particles (<63 microns) are quite mobile and often
undergo many episodes of deposition and resuspension by the variable currents
of tidal waters. In theory, it should be possible to describe and predict
the pathways of fine particle transport in estuaries, based on the physics
of the particle motions and numerical models of sufficient complexity, or
from properly scaled physical models. Actually, it is more practical to make
direct field measurements of particle transport or to use tracers to infer the
net motion of particles over extended periods of time. The approach des-
cribed here uses a "natural" tracer (Cesium-137), which has become associated
with fine particles in estuaries, as a guide to the distribution and trans-
port of fine-grained sediments and several types of pollutants. The pattern
of accumulation of fine particles in estuarine sediments is complex and
essentially unique to each estuary. As a first approximation, estuarine
sediments can be grouped into three end members: (1) large mineral particles,
such as quartz sands, which are relatively unimportant in the transport of
reactive pollutants; (2) fine particles (generally < 63 microns) which have
not acquired significant quantities of pollutants, primarily because they
have had relatively little contact with soluble phase pollutants? and (3)
fine particles with readily measurable quantities of pollutants, which will
be referred to here as "recent" fines. Obviously, the degree of contamina-
tion of recent fines can be extremely variable, but, as will be shown in the
case of the Hudson River Estuary (USA), there is often a relatively uniform
dispersal of reactive pollutants in recent fine particles over large areas
and a surprisingly coherent distribution of several types of pollutants.
CESIUM-137 AS AN INDICATOR OF RECENT SEDIMENTS
Atmospheric testing of large nuclear weapons during the 1950's and early
1960's, predominantly by the USA and USSR, dispersed a great variety of
radionuclides over the entire earth. A number of tnese nuclides have suf-
ficiently long radioactive half-lives to be valuable as tracers of global
scale processes. The pattern and time scale of deposition of Strontium-90
(t^ ^ 29 years), especially in the Northern Hemisphere, have been followed
closely (15, 16) because of its long half-life, potentially serious bio-
logical impact, and the existence of relatively direct pathways by which this
nuclide can reach man. The depositional history of Cs-137 (t^ '^ 30 years)
has not been documented as well as Sr-90 because it does not appear to be of
nearly as much biological concern to man as Sr-90. Available data indicate
that the pattern of delivery of atmospheric fallout Cs-137 to the earth's
surface can be assumed to be identical to Sr-90, with an activity ratio of
Cs-137 to Sr-90 of '^ 1.5 (9, 7). The peak delivery of fallout Cs-137 to the
earth's surface by rain and snow occurred during the years 1962 to 1964;
the quantities deposited since then have been relatively small. Most of the
Sr-90 (and Cs-137) fallout on land has been retained in the upper 10 to 20
cm of the soil profile and the total activity present per unit area is pro-
portional to the annual rainfall (8) as well as being a function of the lati-
tude (15).
In the open ocean, both Sr-90 and Cs-137 appear to have remained pre-
dominantly in solution (3, 6, 1), although there is some indication of prefer-
ential removal of Cs-137 into the sediments (10). The fraction of total fall-
out Cs-137 delivered to the ocean which is now in the sediments is quite small.
103
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In most freshwater lakes, Sr-90 stays in solution to the first approximation,
but Cs-137 is nearly completely removed onto particles (17, 5). In rivers and
estuaries, the fraction of fallout Cs-137 associated with sediment particles
(compared with that which passed through these systems in solution) is not
well-defined (11) , but readily measurable amounts are found in the sediments
of estuaries which we have studied.
We usually measure Cs-137 in estuarine sediments by gamma, counting 50 to
100 gram samples of dried sediment which have undergone no chemical steps to
enrich the specific activity of the samples. Our counting equipment consists
of a high resolution lithium-drifted germanium detector and a multichannel
analyzer, which allows us to simultaneously measure the activity of many other
radionuclides (both natural and artificial) as well as the Cs-137 gamma emis-
sion peak at 662 Kev. Because of our ability to measure Cs-137 at "normal"
environmental levels in sediments with non-destructive gamma counting, we are
able to process a large number of samples with relatively little effort in
laboratory preparation, compared with the analytical techniques required for
most pollutant measurements. The detection limit for most of our samples
was 10 to 20 pCi/kg, which is a few per cent of the activity typical of sur-
face soils in the Northern Hemisphere.
CESIUM-137 AND OTHER ANTHROPOGENIC COMPONENTS IN HUDSON ESTUARY SEDIMENTS
The total delivery of fallout Cs-137 to the Hudson Estuary, decay
corrected to 1975, has been about 120 mCi/km2 (U.S. ERDA, 1975). There is
an additional supply of Cs-137 from a nuclear electrical-generating facility
located near the upstream end of the salinity intrusion in the Hudson. The
total release of Cs-137 from this facility over more than a decade of opera-
tion has been comparable to the amount supplied by rain to the surface of the
Hudson Estuary from global fallout. Thus the direct supply of Cs-137 to the
Hudson Estuary is roughly a factor of two greater than might be expected if
fallout were the only source.
The specific activity of Cs-137 in surface sediments in the Hudson
ranges over more than two orders of magnitude, with the lowest values in
sandy sediments (typical of areas scoured of fine particles by strong
currents). Fine-grained surface sediments (< 63 y) usually range between
0.2 and 2 pCi/g of Cs-137, which is comparable to fallout Cs-137 activity
in surface soils throughout the Northern Hemisphere (7, 12). There is large
variation in the depth to which Cs-137 is found in sediment cores. In most
areas Cs-137 activity is confined to the upper 5 cm of the sediment column,
whereas in others it extends to nearly 3 meters below the sediment surface.
Thus the integrated amount of Cs-137 per unit sediment area is not uniform,
and ranges over more than two orders of magnitude. As a result, relatively
limited geographical areas account for large portions of the total sediment
burden of Cs-137. In the Hudson Estuary (Pig. 1), the dominant areas of
Cs-137 accumulation are the harbor and shallow coves upstream of the harbor.
These areas are not in close proximity to the site of localized discharge of
CS-137 to the Hudson, and primarily reflect the zones in which fine particles
are rapidly accumulating (13).
104
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HUDSON
Hudson Drainage Basin
[PCB'sl
ESTUARY
4I°30'-
40«30'«
73°30'
Figure 1. Locations of cores for which data are reported in this paper are
indicated by ® . The most-northerly sampling sites are near the upstream
limit of saltwater intrusion of the Hudson Estuary during summer months, and
the harbor sites adjacent to New York City usually have salinities of one
half to two thirds that of seawater. The Hudson is tidal for approximately
250 km upstream of New York City. The locations of discharge of polychlori-
nated biphenyls (PCBs), cadmium and Nickel (Cd, Ni), and radioactive cesium
(Cs-137) are also indicated.
105
-------
We have found the distribution of other man-made reactive contaminants
in Hudson sediments to be quite similar to that of Cs-137, despite signifi-
cant differences in chemistry, and mode of input to the system. The loca-
tions of sediment sampling sites for data reported here are shown in Fig. 1.
These sites extend from approximately the upstream limit of salinity intru-
sion during summer months to the harbor area that typically has salinities
of approximately two-thirds of seawater.
In Fig. 2, activities of Pu-239,240, determined by alpha spectrometry
following chemical separation procedures as described by Wong (18), are
plotted against Cs-137 in the same samples. The covariance over two orders
of magnitude of these two parameters .in Hudson sediments is clear. Thus if
the present distribution of Pu-239,240 in Hudson sediments (mostly derived
from fallout) were to be measured, the most efficient procedure would be to
use the distribution of Cs-137, which is relatively easy to measure by gamma
spectrometry, to guide the selection of samples for Pu-239,240 analysis.
(The alpha particle energies of Pu-239 and Pu-240 are nearly identical and
the sum of their activities is usually reported.)
In Fig. 3, the concentration of polychlorinated biphenyls (PCBs) in
Hudson sediments is plotted against Cs-137. Although our data are limited at
this time, the covariance of these constituents is also obvious. The levels
of PCBs are high in sediments over large areas of the Hudson because of
industrial releases during the 1950's and 1960's at two sites more than 200
km upstream from the locations of our sampling area. Considering the great
differences in chemistry between Cs-137 and PCBs, it is perhaps surprising
to find their sediment distributions to be as similar as they are, but their
covariance is a good indicator of the ability of fine particles to transport
and accumulate quite a variety of reactive pollutants.
Fig. 4 shows the concentration of several trace metals relative to
Cs-137. Zinc, copper, and lead concentrations in recent Hudson sediments are
several times the concentration levels in pre-industrial sediments. All of
the samples shown in Fig. 4 are upstream of the harbor area, and thus
reflect diffuse sources of these metals to the Hudson over a number of
decades. Sediment samples from New York Harbor have somewhat higher con-
centrations for all three metals, because of discharges from the electro-
plating industry. Vertical distributions of all three metals in harbor sedi-
ments also are similar to that of Cs-137-
In Fig. 5 the concentrations of cadmium and nickel in a small cove
are plotted against Cs-137 activity. High level contamination of the sedi-
ments of this small (^ 0.5 km2) shallow (mean depth i-o 1-2 meters) area by
effluent from a battery factory has resulted in Cd concentrations ranging
from a few per cent to ^100 ppm (2). Some surface sediments in the cove
which are apparently in areas of active current scouring contain relatively
low concentrations of Cd, Ni, and Cs-137. Thus Cs-137 is useful in mapping
the pattern of trace metal accumulation in sediments in relatively small,
highly contaminated areas, as well as for diffuse sources over large areas.
All of the "reactive" pollutants we measured in Hudson Estuary sediments
are found preferentially in fine particles and in sediments rich in organic
106
-------
100
Cs-137 (pCi/kg)
1000
Figure 2. Activities of Cs-137 and Pu-239,240 in Hudson Estuary sediment.
Samples are given for sites indicated in Fig. 1. Data are for
samples well below the sediment-water interface, as well as sur-
face sediment samples. Two suspended particulate samples (A)
collected near the middle of the sampling range are also included.
All data are expressed as activity per dry weight of sediment.
107
-------
cr
.at
\
cr
CD
O
Q.
_J
100
Cs-137 (pCiAg)
1000
Figure 3. Activities of Cs-137 and concentrations of polychlorinated
biphenyls (PCBs) in samples of surface sediment are given for
Hudson Estuary sites included in Fig. 1. All data are expressed
in terms of dry weight. PCBs were soxhlet-extracted from the
sediments, by azeotropic hexane acetone and quantified by elec-
tron capture gas chromatography.
108
-------
I
1000 2000
Cs-137 (pCi/kg)
i
3000
Figure 4. Activities of Cs-137 and concentrations of zinc (X), copper (A) ,
and lead (0) in Hudson Estuary sediment samples are plotted for
sites indicated in Fig. 1. Data are for samples well below the
sediment-water interface as well as surface sediment samples.
The data are presented on a linear plot to indicate the observed
range of pre-industrial concentrations in Hudson sediments on the
Y axis. All data are expressed in terms of dry weight. All trace
metal data reported here were obtained by flame atomic absorption
spectrometry.
109
-------
100
CJ
10
100
Cs-i37 (pCi/kg)
000
Figure 5. Activities of Cs-137 and concentrations of cadmium (®) and nickel
(©) are given for sediment samples from a small cove in the Hudson receiv-
ing effluent from a battery factory (see insert in Pig. 1 where locations
of samples are indicated by@'s). Some of the lowest concentrations are
from surface samples of fine-grained sediment in areas which are apparently
scoured by tidal currents and are thus kept free of recently deposited sedi-
ments. Samples from these scoured sites have a similar physical appearance
to those from the highly contaminated sites. The trend lines drawn for Cd
and Ni are not fitted mathematically, and do not imply a linear relation-
ship between Cd, Ni and Cs-137 on a log-log plot. The lines are included
primarily to indicate that samples in this highly contaminated cove which
have low activities of Cs-137, also have relatively little Cd and Ni concen-
tration. The background concentrations of Ni are more than an order of
magnitude higher than for Cd, which causes the slopes of the two trend lines
to differ significantly.
110
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matter, as would be expected. However, many sediment samples with very
similar particle size distributions and organic carbon contents did not have
appreciable reactive pollutant concentrations (and they did not have measur-
able Cs-137). Thus the activity of Cs-137 was a much more accurate indicator
of probable pollutant concentration than were classical sedimentological
techniques, especially in estimating the depth to which appreciable pollutant
concentrations would be found in estuary sediment cores.
CESIUM-137 AS A POLLUTANT TRACER IN OTHER AQUEOUS SYSTEMS
Fallout Cs-137 has been used as an indicator of recent sediments in the
Delaware Estuary. Sites with appreciable activity of Cs-137 in surface sedi-
ments also have hydrocarbon constituents typical of recent pollution, whereas
surface sediments free of Cs-137 has been shown to be nonuniform in large
lakes and to be closely related to that of fallout Pu-239,240 (4).
The concentration of a number of reactive pollutants in Hudson Estuary
sediments, although extremely variable in both surface and depth distribu-
tions, has been shown to have considerable coherence from one pollutant to
another and to have a strong correlation with Cs-137. Thus the task of
mapping contaminated sediment distributions in complicated sedimentary
regimes can be simplified through the use of a "natural" tracer, Cs-137.
ACKNOWLEDGEMENTS
Financial support for the research reported here was provided by the
U. S. Environmental Protection Agency (R803113) and the U. S. Energy Research
and Development Administration (E (11-1) 2529). Contribution No. 2479 from
Lamont-Doherty Geological Observatory of Columbia University.
Ill
-------
REFERENCES
1. Bowen, V.T., and W. Roether. 1973. Vertical Distributions of Strontium-
90, Cesium-137, and Tritium near 45° North in the Atlantic, J.
Geophys. Res., 78, pp. 6277-6285.
2. Bower, P.M. 1976. Burdens of Industrial Cadmium and Nickel in the
Sediments of Doundry Cove, Cold Spring, New York. M.S. Thesis,
Queens College of the City University of New York, 162 pp.
3. Broecker, W.S., E.R. Bonebakker, and G.G. Rocco. The Vertical Distri-
bution of Cesium-137 and Strontium-90 in the Oceans, 2, J. Geophys.
Res., 71, pp. 199-2003.
4. Edgington, D.N., J.J. Alberts, M.A. Wahlgren, J. O. Karttunen, and
C.A. Reeve. 1976. Plutonium and Americium in Lake Michigan Sedi-
ments, Transuranium Nuclides in the Environment, IAEA-SM-199/47,
IAEA, Vienna, pp. 493-516.
5. Farmer, J.G., V.T. Bowen, and V.E. Noshkin. 1977. Long-lived Artificial
Radionuclides in Lake Ontario, I. Supply from Fallout, and Concentra-
tions in Lake Water of Plutonium, Americium, Strontium-90 and Cesium-
137. (Submitted to Limnology and Oceanography..)
6. Folsom, T.R., C. Sreekumaran, N. Hansen, J.M. Moore, and R. Grismore.
1970. Some Concentrations of Cs-137 at Moderate Depths in the
Pacific 1965-1968. U. S. Atomic Energy Commission (AEC) Rep.
HASL-217, pp. 1-9.
7. Hardy, E.P. 1974. Depth Distributions of Global Fallout Sr-90, Cs-137,
and Pu-239,240 in Sandy Loam Soil. U. S. AEC Rep. HASL-217, pp. 1-9.
8. Hardy, E.P., and L.T. Alexander. 1962. Rainfall and Deposition of
Sr-90 in Clallam County, Washington. Science, 136, pp. 881-882.
9. Harley, N., I. Fisenne, L.D.Y. Ong, and J. Harley. 1965. Fission Yield
and Fission Product Decay. U. S. AEC Rep. HASL-164.
10. Noshkin, V.E., and V.T. Bowen. 1973. Concentrations and Distributions
of Long-lived Fallout Radionuclides in Open Ocean Sediments, Radio-
active Contamination of the Marine Environment. IAEA, Vienna,
pp. 671-686.
112
-------
11. Riel, G.K. 1972. The Distribution of Fallout Cesium-137 in the Chesa-
peake Bay. Proceedings of the Second International Symposium on the
Natural Radiation Environment, J.A.S. Adams, W.M. Lowder,
T.F. Gesell, eds. pp. 883-896.
12. Ritchie, J.C., P.H. Hawks, and J.R. McHenry. 1975. Deposition Rates in
Valleys Determined Using Fallout Cesium-137. Geol. Soc. Amer. Bull.,
86, pp. 1128-1130.
13. Simpson, H.J., C.R. Olsen, R.M. Trier, and S.C. Williams. 1976. Man-
made Radionuclides and Sedimentation in the Hudson River Estuary.
Science, 194, pp. 179-183.
14. U. S. Energy Research and Deveopment Administration (ERDA) Rep. HASL-294
1975, appendix, pp. 68-70.
15. Volchok, H.L. 1966. The Global Strontium-90 Budget, J. Geophys. Res.,
71, pp. 1515-1518.
16. Volchok, H.L., and M.T. Kleinman. 1971. Global Sr-90 Fallout and
Precipitation: Summary of the Data by 10 Degree Bands of Latitude,
U.S. AEC Rep. HASL-245, pp. 2-83.
17. Wahlgren, M.A., and J.S. Marshall. 1975. The Behavior of Plutonium and
Other Long-lived Radionuclides in Lake Michigan: I. Biological Trans-
port, Seasonal Cycling and Residence Times in the Water Column,
International Symposium on Transuranium Nuclides in the Environment.
IAEA-SM-198/39, IAEA, Vienna, pp. 227.
18. Wong, K.M. 1971. Radiochemical Determination of Plutonium in Seawater,
Sediments, and Organisms. Anal. Chim. Acta, 56, pp. 355-364.
113
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THE DISTRIBUTION OF POLLUTANTS IN THE CARIBBEAN BASIN
M.M. Domanov, B.A. Nelepo, and V.N. Stepanov
P.P. Shershov Oceanology Institute, U.S.S.R. Academy of Sciences
The authors of this paper took part in the
research work conducted during recent years in the
Caribbean Sea and the Gulf of Mexico under the auspices
of United Nations Education, Scientific, and Cultural
Organization (UNESCO). The hydrographical investigations,
conducted in 1973 on board the r/v Akademik Kurchatov,
confirm the general statement that oil and chemical pollu-
tion is increasing, while the danger of radioactive contam-
ination shows a decrease.
OIL POLLUTION
Large spots and streaks of oil were encountered everywhere along our
route. Most pollution was found in the waters of the Caribbean Sea and the
Gulf of Mexico. The strong, steady Caribbean current carries the oil emitted
by tankers in the central part of the Caribbean Sea (from the Lesser Antilles
to the Yucatan Channel).
In the northern part of the Caribbean Sea, where according to our inves-
tigations an anticyclonic circulation prevails, oil products will accumulate
in the central parts of such gyres (Fig. 1) situated near the Great Antilles.
In the southern part of the sea, a rather intensive cyclonic circulation was
discovered. Thus, oil will be carried to the margins of these systems, pollu-
ting the coasts of Colombia and Venezuella.
In the Gulf of Mexico, the main mass of oil entering through the
Yucatan Channel will be carried away to the coasts of Cuba and Florida and
thereafter through the Florida Straits into the open ocean. In the western
part of the Gulf, the pollutants will spread from north to south along the
coasts, and accumulate in open aquatories in the separate closed gyres situ-
ated in this region.
Our plankton nets brought up great quantities of small lumps of black
oil, varying in size from a poppy seed to several centimeters in diameter.
Small animals, cirripeds, actinians, and hydroids are frequently found
attached to their surfaces. Larger pieces have small-hole refuges made by
tiny crustaceans. This circumstance cannot avoid affecting the biological
resources of the world's oceans, as plankton forms the basis of the aquatic
food chain. The adverse effect exercised by oil pollution on phytoplankton
may lead to a decrease in oxygen production by marine algae. If this gas is
114
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generated by the life activity of plants on our planet, the share demanded by
phytoplankton of planetary oxygen must be very substantial.
co-
Figure 1.
The scheme of the distribution of the radioactive pollution.
Concentration of the strontium-90 in disintegrations per
minute in 100 m of the water according to the available data.
Sites measured are marked by Roman numerals.
TOXIC CHEMICALS IN THE OCEAN
The Mexican oceanographers who stayed for some time aboard the Akademik
Kurchatov told us about heavy pollution of seawater by chemical fertilizers
carried into the ocean with river discharge. Special investigations are con-
ducted to determine the content of DDT and other pesticides in the bodies of
fish and crustaceans. These chemicals tend to accumulate in great quantities
in the tissues of living organisms and are not easily eliminated. In human
organisms, they penetrate with ingested contaminated seafood.
Such investigations are of special importance to the western part of the
Gulf of Mexico, into which the Mississippi River empties. The waters of this
river, the greatest on our planet, flow through 31 states enroute to the sea
and carry a heavy load of toxic chemicals. They spread along the western and
southern coasts of Mexico and are carried by the Florida current into the open
ocean.
ARTIFICIAL RADIOACTIVITY IN THE CARIBBEAN BASIN
The investigations conducted aboard the Akademik Kurchatov yielded some
information on the changes with depth in the content of radionuclides of arti-
ficial origin. The investigations were conducted at separate polygons con-
fined to the deep sea depressions (trenches) of the Caribbean Basin and the
Cayman Trough (Fig. 1). For comparison with oceanic conditions, one of the
polygons was confined to the Puerto Rican Trough situated northward of Puerto
Rico. The concentration of cesium-137 was determined by means of ion-exchange
115
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resins sunk at different distances between the surface and the bottom. Deter-
minations were made of the nature and intensity of atmospheric radioactive
fallouts.
The data obtained show that maximum concentrations of radionuclides occur,
not at the surface of the ocean as believed earlier, but at depth of about
200 m. A direct relation was found to exist between the changes in depth and
the concentration of radioisotopes and general physico-chemical stratification
of the waters. The maximum concentrations of radionuclides discovered in the
subsurface layer coincide with the layer of extreme salinity values.*
The concentration of cesium-137, low at the surface, increases rapidly
with depth, reaches its maximum value in the lower layer of surface waters,
and decreases gradually down to 100 m (Fig. 2). An exception is the profile
obtained in the Gulf of Mexico where maximum radioactivity is found at the
surface. This seems to be accounted for by the ascent of subsurface waters
coming from the Caribbean Sea. If the analogy with salinity holds through
the whole water column, then the concentration of radionuclides may be expected
to show a certain increase toward the bottom, following the minimum values
observed at the core of the intermediate waters and extending down to 800 to
1000 m.
Figure 2. The water circulation on the surface from
the reference level of the 2500 m.
The only possible local source of pollution could be the U. S. atomic
industry. If uranium fissure products were released, then higher concentra-
tions of strontium and cesium would be recorded in the Gulf of Mexico and in
the Florida Straits where waters are carried into the open ocean. But avail-
able data show that the concentrations here are of the same order as those in
the Caribbean Sea. Consequently, radionuclides of artificial origin must be
carried in from the open part of the Atlantic Ocean.
*The surface waters are divided into three layers. The upper homogeneous
layer has an average thickness of 20-50 m. The lower, or subsurface layer, is
situated in depths varying from 50-100 to 250-300 m. They are separated by a
relatively thin transition layer.
-------
Considering the intensive transport of oceanic waters through the
Caribbean basin, the above assumption is highly plausible. To make certain,
we analyzed the data on strontium-90 concentration in the surface waters of
the northern Atlantic, published by the U.S. HASL (1968). The data permitted
us to establish a prevailing importance of strontium-90 in currents capable
of transporting radioisotopes to the Caribbean Sea (Fig. 1). Corresponding
concentrations were discovered in adjacent areas of the Caribbean Sea: the
low values observed in the south and southeast increased to 40 to 50
dec/100£/min at the Antilles Straits.
How are the high concentrations of radio-isotopes found in the lower
layer of surface waters formed? The explanation apparently lies in the fact
that surface water is drawn to the depths in the central regions of anti-
cyclonic microcirculation systems and zones of convergence. The sunken waters
begin to shift in the subsurface layer in a horizontal direction. In the
Caribbean basin, judging from the relation between maximum radioisotope con-
centration and extreme salinity value, sinking of surface water in the open
ocean is a most important factor in the western part of the subtropical anti-
cyclonic macrocirculation. It is precisely at this point that the highest
concentrations of radio-active substances are recorded (Fig. 1).
Owing to extensive descending movements, intermediate and deep-water
masses are formed in the North Atlantic Ocean where the radioisotopes are
carried into greater depths with the sinking surface waters. However, con-
sidering the immense volumes of the water masses involved, the concentrations
cannot be of any substantial importance. On the-other hand, the water mass in
the subsurface layer is immeasurably smaller, and conditions there are favor-
able for the accumulation of uranium decay products. These processes are
responsible for the changes with depth in the content of radioactive sub-
stances observed in the lower latitudes of the northern Atlantic and in the
Caribbean Basin.
In areas where ascending movements generated in cyclonic macrocirculation
systems and zones of divergence prevail, radionuclides carried previously to
the depths may begin to shift upwards toward the ocean surface. In this way,
in conformity with the patterns of vertical circulation, the exchange of sub-
stances concentrated in the world's oceans is achieved.
In addition to being transported, a local vertical exchange of radio-
active products must take place in the Caribbean basin. In the northern part
of the sea, in conformity with the peculiarities of its circulation, the
radioisotopes will be carried down by the descending water movements generated
by anticyclonic gyres (Fig. 3). Whereas in its southern part where cyclonic
circulation prevails, the radioactivity at the surface will be increased by
the decay products brought up from the subsurface layer.
In the Gulf of Mexico, under conditions of an extremely complex circula-
tion, including numerous local rises and sinkings of water masses, the radio-
activity field will display a great diversity of changes in concentration and
stratification. On the whole, however, a transport of radionuclides to the
surface may be expected. This has been discovered to be the case at polygon
VI, the Gulf of Mexico.
117
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Co.««OC"ift %o
isoa is.sa J&oo JAJO
J600 J4.W
M.U lion
100 too Joo
Figure 3. The vertical distribution of the cesium-137 (unbroken line) and
salinity (broken line) by the data of the Academic Kurschatov
expedition in the 1974 year.
118
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An estimate was made of the balance of radioactive substances in the
Caribbean Basin from data on radioisotope concentration and water exchange
through the Antilles Straits. In order to convert the conventional radio-
activity units into absolute units, the concentrations of strontium-90 at the
surface of the ocean published by the U.S. HASL (1968) were compared with the
values obtainedfby the isotope-exchange methods. As the conventional units of
this method agree, within the measurements precision, with the absolute values
of cesium-137 expressed in disintegrations per lOOfc per minute, the same rela-
tionship also may be assumed to hold for other radionuclides (Table 1). A
substantial difference was discovered only at polygon VI in the Gulf of Mexico,
which, as stated above, was caused by an increase in concentration associated
with the ascention of subsurface waters.
TABLE 1. COMPARISON OF RADIOISOTOPE CONCENTRATIONS IN CONDITIONAL
AND ABSOLUTE UNITS
Region
of
.dimension
Concentrations
Conditional units
according to "Aka-
demik Kurchatov"
of radionucleids
Absolute units .disinte-
gration/100 litres/min
according to HASL
„ 137 137 „ 90
Cs Cs Sr
Florida Strait
The Lesser Antilles Straits
Venezuela Basin
Westward Passage
Mona Passage
Gulf of Mexico
98
13
60
88
68
161
85 50
17 10
61 36
85 50
68 40
49 29
Calculations of the stock radiocesium (Table 2) show that the oceanic
waters flowing in from the north carry 10 times more cesium-137 than waters
coming from the equatorial zone. The high concentrations observed at polygons
IV and V are apparently caused by an inflow of water from subtropical regions
through the Windward and Mona Passages. As the radiocesium concentrations at
these polygons are rather similar, it may be assumed that the same amounts of
radionuclides are transported from the Caribbean Sea into the Gulf of Mexico,
and, further, through the Florida Straits into the open ocean again.
Proceeding from the stock of radiocesium, the value of water inflow
through the Antilles Straits, and assuming that the main mass of radionuclides
is transported in the upper 1000 m layer, it is possible to calculate the
quantities transported through the channel. The results of our computations
are presented in Table 3. Owing to the lack of direct measurements for the
Florida Straits, we used the relation between the changes with depth in salin-
ity and radioactivity. The total value of the stock of radioisotopes in the
119
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TABLE 2. RADIOISOTOPES CONTENT IN THE 0-1000 m LAYER*
to
o
Region
of
observations
Puerto-Rico Trough
(polygon I)
Anegada Passage
Grenada Trough
(polygon 2)
Venezuela
(polygon 3)
Windward Passage
Radio isotopes content
Conventional units Disintegration (km^min x 10^) Curies (km3lo~3)
137 137 90 137 90
Cs Cs Sr Cs Sr
70.5 70.5 41.4 3.17 1
21.2 21.2 12.4 0.95 0
6.5 6.5 3.8 0.29 0
13.7 13.7 8.1 0.62 0
76 76 44.1 3.42 2
.86
.56
.17
.36
.0
The Bartlett Deep of
the Cayman Trough
(polygon 5) 37 37 21.8 1.66 0.98
The Orient Deep of the
Cayman Trough
(polygon 5) 36.4 36.4 21.4 1.64 0.96
Gulf of Mexico
(polygon 6) 5.8 5.8 3.3 0.26 0.15
*According to the Akademlk Kurchatov expendition.
-------
TABLE 3. WATER AND RADIONUCLlDE TRANSPORT IN THE UPPER 1000-M LAYER
OF THE AMERICAN MEDITERRANEAN
Stock of
radionuclides
disintegrated
km3/min.xl07
Straits Sr90 Cs137
Florida 21.8 37
Windward 44.7 76
Mona 41.4 70.5
Anegada 12.4 21.2
Lesser Antilles 3.7 6.3
Inflow
Water
Volume
km3/sec.x
xlO-3
0.7
12.7
1.9
2.3
17.4
Total
Outflow
Radionuclides Water Radionuclides
disintegrated volume disintegrated
min.xlO7 km3/sec.x min.xlO7
cr-yu pG13/
OJ. ^o
15.2 25.8
565 965
78.5 134
28.6 49
64.5 110
inflow
xlo-3 Sr90
26 565
4 178
0.3 12.5
4.7 58.3
-
Total o-utflow
Csl37
962
302
21.2
99.5
-
35
751.8 1283.8
3.48-10
-3
5.8-10
-3
35 813.8 1384.7
3.66-10-3 6.23-10-3
curies curies
curies
curies
-------
0 to 1000-m layer is assumed to be the same as that of Polygon IV.
The value of the stock of radiocesium in the waters flowing in through
the Windward and Anagada Passages (instrumental measurements for cesium-137
are not available) are derived from the equation of radionuclide balance; an
estimate was made of the total quantities brought into the Caribbean Sea
through the Antilles Straits and carried out into the ocean through the
Straits of Florida (Table 3). A certain excess of outflow over inflow is
probably due to underestimating the quantity of radioisotopes carried away
by the intermediate waters.
As compared with the level of radioactive pollution in European seawater,
the values recorded in the Caribbean Basin are relatively low. This evidence
supports our assumption that radioactive contamination in the Caribbean Basin
depends not on the release of nuclear wastes by local atomic industry, but on
the general level of contamination in the ocean as a whole. We have here an
illustration of the role of global pollution in the destiny of individual
regions. It becomes increasingly evident that it is practically impossible
to solve the problem by local efforts.
Most important in preventing pollution and poisoning of the world's
oceans is the cooperation of the general public. It is in this light that
the data collected by the Akademik Kurchatov present a certain interest.
122
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35.00 35.50 3&00 36.50
200 300 400
200
WOO
Figure 4. The alteration of the cesium-137 concentration
in the Florida Strait (unbroken line), calculated
after the salinity (dotted line).
123
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REFERENCES
1. Nelepo, B.A., and M. M. Domanov. 1973. The Ion-exchange Method of the
Control of the Ces±um-137 Contents in Seawater. Oceanolog±ja,13 ('4)~
pp. 602-605.
2. Stepanov, V.N. 1974. The World's Oceans: the Dynamics and Properties
of Seawater. M., Znanie, p. 255.
3. Stepanov, V.N., R.P. Bulatov, B.V. Volostnykh, and S.G. Panfilova. 1975.
The Formation of the Physical and Chemical Properties and the Water
Dynamics of the American Mediterranean Sea. M., Nauka, Trudy, VI
Conference on the Sea Chemistry, pp. 79-110.
4. U.S. Atomic Energy Commission. 1968. U.S. AEC Rep. HASL-197. p. 352.
5. Hasl 197, UASEC, N.Y., 10014. 1968. 352 pp.
124
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SUSPENDED PARTICULATE MATTER AND NATURAL RADIONUCLIDES AS TRACERS OF
POLLUTANT TRANSPORTS IN CONTINENTAL SHELF WATERS OF THE EASTERN U.S.
Pierre E. Biscaye, Curtis R. Olsen and Guy Mathieu
Lamont-Doherty Geological Observatory of Columbia University
Palisades, New York 10968
ABSTRACT
We have begun to study the dispersion of
anthropogenic pollutants by examining the suspended
particulate phases with which many pollutants are
associated and on which they are transported in the
marine environment. The populations of suspended
particle types, their distribution, and their associa-
tions with trace metal pollutants have been analyzed by
examining individual particles, using combined scanning
electron microscopy (SEM) and energy-dispersive x-ray
fluorescence (EDXRF). The distribution of discrete
pollutant particles (e.g. Ti-oxides, and trace-metal
bearing organic particles that have their origins in
the Apex of the New York Bight) suggests paths by which
these pollutants are dispersed across the continental
shelf. Gross features of surface and near-bottom sus-
pended particle concentrations reflect vertical and
horizontal mixing processes and indicate a flux of
particles both into and out of the sediments. The
distribution of excess radon, which also diffuses
from the sediments (particularly fine-grained sedi-
ments), is similar to that of near-bottom suspended
particles. The similarity in the horizontal and
vertical distribution of this natural tracer to that
of suspended particles (particularly during times of
vertical stratification of* the water column) suggests
that the modelling the dispersion of radon will yield
information on the rates of dispersion and removal of
suspended particulates from the water column.
INTRODUCTION
The role of suspended particles in the marine cycles of many elements
only recently received attention from a quantitative point of view. The work
of A.P. Lisitzin (7 and references therein) may be regarded as a pioneering
effort in the nature and role of suspended particulate matter in the marine
125.
-------
environment. The sources of suspended particles to marine waters are multiple
and difficult to resolve: continental runoff and fluvial detritus, infall of
atmospheric dust, in situ production (primarily in the euphotic zone by bio-
logic activity), and direct anthropogenic inputs (especially adjacent to
heavily populated, industrial areas such as New York). For example, Gross (6)
estimates that the quantity of waste material dumped in the shelf waters
adjacent to the New York metropolitan area exceeds that transported by lit-
toral drift processes and by rivers including the Hudson River which debouches
into the New York Bight at New York City. The New York Bight is that area of
the continental shelf that lies within the coastline angle made by the inter-
section at New York City of Long Island (New York) and New Jersey. These
wastes include industrial solids and liquids, construction rubble, sewage
sludge and harbor dredge spoils (much of which is fine-grained), and carry a
significant burden of trace metals and other pollutants.
Once removed from the water column by adsoption onto or incorporation
into particulate matter which has settled to the bottom, pollutants and their
particulate hosts do not remain forever out of the system. Complex chemical
processes (of which most are related to biological processes) occur at or near
the sediment-water interface and may alter the chemical and physical state of
the pollutants. In addition, particulate-associated pollutants may be rein-
troduced into the water column and undergo further dispersion by resuspension.
In areas of the deep sea where abyssal currents contact the bottom, a signifi-
cant portion of the suspended particulate standing crop in the water column is
due to resuspension (2). In the shallow water regions of continental shelves,
resuspension of particles and their burden of pollutants may be expected to be
even more important.
This paper is concerned with the distributions of suspended particulate
matter particularly in the lower part of the water column in the continental
shelf and upper continental slope of the New York Bight. These distributions
will be compared with that of excess radon-222, a naturally occurring radio-
active gas (half life = 3.85 d) that originates in surficial sediments and
therefore constitutes a radioactive tracer of near-bottom processes. We will
also describe a technique we have used to characterize the nature of suspended
particulate matter and its composition.
SAMPLING AND ANALYTICAL METHODS
Our sampling in the New York Bight was done primarily on three seasonal
cruises: October 1974 (V32-01), July 1975 (RC 19-01) and January 1976 (RC
19-05). Samples were taken on serial casts of 30-& Niskin bottles for which
the bottom proximity of the lowermost bottle was determined by a pinger. The
internal springs of these bottles are Teflon-coated, the air that replaces
water upon evacuation of the water sample is filtered to prevent contamination
from shipboard air. Water samples are sucked directly through preweighed
Nuclepore membrane filters (0.4ym pore size; 47 mm diameter) into evacuated
flint-glass bottles for subsequent extraction of radon. Thus suspended part-
icle analyses are done on the same 2QH sample as used for radon, except in the
case of very turbid near-bottom or nearshore water where a separate, smaller
aliquot is filtered for suspended particulates. Subsequent handling of the
filters to yield a concentration of total suspended particulate matter is des-
126
-------
cribed in Biscaye and Ettreim (1) and Brewer et al. (4). The analytical
method for radon (extraction by gas exchange and scintillation counting) is
essentially the same method as that described by Broecker (5).
Much of the previous work on the composition of suspended particulate
matter has been analytical techniques such as carbon-hydrogen-nitrogen anal-
yses of organic constituents, instrumental neutron activation, x-ray fluor-
escence or atomic absorption analyses on bulk samples. Such characteriza-
tions of the bulk nature of the sample have the advantage of results with
good analytical precision. The data can be used to derive statistical corre-
lations between various elements as an insight into their geochemical behavior
or can be interpreted with the aid of numerical models. Rather than a bulk
analytical method, our approach has been to examine discrete particles, using
combined scanning electron microscopy (SEM) and energy-dispersive x-ray fluo-
resence (EDXRF). An advantage is that one observes the nature of the partic-
ulate matter directly and can gain morphological information as well as direct
information on associations of different particle types and associations of
trace metals with particle types. Disadvantages are that this type of data
is difficult to quantify and the analytical work is tedious. We regard this
type of analysis as complementary to, rather than an alternative to, bulk
analytical methods; a program of bulk sample x-ray fluorescence has begun in
our laboratory.
SEM-EDXRF CHARACTERIZATION OF NEW YORK BIGHT SUSPENDED PARTICULATE MATTER
Small portions of Nuclepore filters are mounted on SEM stubs, vapor-
coated with carbon and palladium and examined in the SEM. The EDXRF probe
attached to our SEM can detect characteristic x-rays from elements with atomic
number 9 or greater. Therefore, major constituents of organic matter (such as
carbon and nitrogen) are not detected. The classification scheme of major
particle types is given in detail in Biscaye and Olsen (3) and consists of two
major divisions—Biogenic and Nonbiogenic (each contains two or more subdi-
visions) . Biogenic particles include both those consisting primarily of or-
ganic material and those consisting of inorganic test material such as cal-
cium carbonate, strontium sulfate, or opaline silica (such as the diatoms in
Fig. 1). The organic particles show either no x-ray spectrum (and therefore
consist of elements with atomic number less than nine) or are characterized
by the presence of phosphorus with or without accompanying sulfur, chlorine,
or both. An example of this kind of organic particle and its x-ray spectrum
is shown in Fig. 2.
The other major division, Nonbiogenic, consists primarily of aluminosili-
cate particles (which includes clay, as well as non-hydrous minerals) charac-
terized by the presence of aluminum and silicon x-ray lines with varying com-
binations of sodium, magnesium, potassium, calcium, and iron. Other nonbio-
genic particles, however, include non-aluminosilicate minerals such as quartz,
pyrite, dolomite, barite, sphene, and oxides of iron and titanium. Examples of
nonbiogenic particles and their characteristic x-ray spectra are given in
Figs. 3, 4, and 5. Clues to the identity of a given particle are sometimes
conveyed in its morphology as in the obvious case of the diatoms in Fig. 1 or,
less obviously, in Figs. 3 and 5. But for the overwhelming majority of parti-
cles, many of which are broken and fragmented, identification of the nature of
the particle is only possible from the x-ray spectra.
127
-------
NJ
03
Figure 1.
Fe
Siliceous centric diatoms from the Bight apex. Note the Fe peak in the x-ray
spectrum. Fe and frequently Ti coat much of the suspended matter in the apex.
Palladium on this and all the x-ray spectra shown CFigs. 2 to 5) is from the
metallic vapor coating used to prepare the sample for SEM.
-------
Figure 2.
Cu Zn
Organic particles from the waters of the Bight apex, near the disposal
sites for sewage sludge and dredge spoils. Note definitive P peak and
high concentrations of Fe, Cu, and Zn.
-------
OJ
o
Al Si Pd K
Figure 3. Muscovite flake from near-bottom waters of the outer shelf.
-------
to
I—1
/ I \ \
Mg Al Si S Pd K Ca
Fe
Figure 4.
Aggregate of Mg-K-Ca-Fe aluminosilicate suspended particle typical of near-bottom
waters of the outer continental shelf and upper continental slope.
-------
Mg Si Pd Ca
J
Fe
Figure 5.
Pyroxene grain from near-bottom waters of the upper continental slope.
Note cleavage which sometimes aids in identification of specific minerals,
e.g. pyroxenes, micas, feldspars, dolomite, etc.
-------
U)
RATIO OF 55m-
AK-ALUMINOSILICATE S
Mg-K-Co-Fe Aluminosilicate
Particles (by number)
74
Figure 6. Ratio of the abundance (by number of particles) of KT^aluminosilicates to Mg-K-Ca-Fe
aluminosilicates in near-bottom waters of the New York Bight. Note the sharpe decrease
in the ratio toward the edge of the continental shelf and beyond.
-------
We have thus far examined primarily filters taken within about 10 meters
of the bottom and can make the following generalizations about the distribu-
tion of particle types in the New York Bight.
The biogenic skeletal debris is predominantly siliceous, consisting pri-
marily of diatoms (Fig. 1) with some silicoflagellates and a few radiolarian
fragments. Calcareous skeletal debris (primarily coccoliths) becomes more
abundant in waters near and beyond the shelf break.
Organic particles in nearshore waters are characterized by strong P peaks
relative to Si and Al, indicating little aggregation with or incorporation of
aluminosilicate material. These nearshore organic particles are frequently
observed to contain high concentrations of Fe, Mn, Ti, Cu, Sn, Cr, Zn, Pb, Ni,
and/or As. Although organic particles containing Fe and Mn are ubiquitous in
the New York Bight, those detectable (at least per mil) quantities of Ti, Cu,
Sn, Cr, Zn, Pb, Ni, and As, are most abundant in the Bight Apex (near the out-
flow of the Hudson River) and the disposal sites for sewage sludge and dredged
harbor spoils. Consequently, it appears that the dumped wastes are the most
likely source for these rare metal-bearing organic particles. Their dispersal
from the Bight Apex may be useful in studying particle transport processes on
the shelf. In addition, detectable concentrations of trace metals (other than
Fe and Mn), when observed, were almost invariably associated with organic
particles.
Organic particles in the outer shelf waters (especially near the bottom)
were commonly observed as large masses of organic-clay aggregates, showing a
relatively small P peak but only occasionally detectable trace metals (other
than Fe and Mn).
Although organic matter and skeletal debris comprise a considerable por-
tion of the suspended matter in the surface and intermediate waters of the
Bight, there is a marked decrease relative to the nonbiogenic fraction in
near-bottom waters. The nonbiogenic fraction consisted of clay aggregates and
individual mineral grains. The bulk clay mineral composition of the suspended
matter in the Bight is more than 50 per cent illite with less chlorite, and
still less montmorillonite, mixed layer clays, and kaolinite (8). Identifiable
mineral grains consisted of quartz, K-feldspar,- palgioclase, muscovite
(Fig. 3), biotite, chlorite, dolomite, and heavy minerals such as amphiboles,
pyroxenes (Fig. 5), sphene and barite.
A marked change in mineralogy of the aluminosilicate suspended matter
occurs at the shelf break. In nearshore waters, and in surface waters of the
outer shelf, the predominant aluminosilicates are K-rich. In the near-bottom
waters along the upper continental slope and in the Hudson Canyon, Mg-Ca-K-Fe
other seasons, the concentrations are high in the Hudson Canyon and low in the
zone parallel to the slope and centered at -^ 1500-2000 m depth. Strong verti-
cle and horizontal mixing over most of the shelf during January blurs the
differences between surface-produced and resuspended particle distributions.
This contrast with the July data points up the importance of the thermocline
in separating the two regimes and the processes that control the distribution
of particulate matter within them.
134
-------
The distribution of near-bottom excess radon for the three cruises is
shown in Pigs. 12, 13, and 14. Several features of these distributions,
similar to those of the distributions of near-bottom suspended particles
(Figs. 7, 8, and 9), point to their similar origins and suggest that their
distribution in the water column is controlled by similar processes. These
features are: (1) patches of high concentrations of excess radon approximately
coincident with those of suspended particulate matter (as in the suspended
particles, the patches of high concentrations of radon are less distinct dur-
ing the stratified October and July regimes); (2) coincidence of the upper
slope zone of minimum concentration of suspended particles (centered some-
where between about the 1500 and 2000 isobath) with a minimum in near-bottom
concentration of excess radon.
Comparison of both the near-bottom suspended particulate and excess radon
distributions with the distribution of bottom sediment type suggests in part,
the control for the observations. The parameter chosen to characterize the
bottom sediment is the weight percentage finer than 63 ym diameter (Fig. 15).
The data are based on samples taken at each location shown in Figs. 7 to 9,
but most of the data come from Schlee (10 and unpublished data). The relicit
glacial-age Shelf Channel of the Hudson River (approximately defined by the
55m isobath) is seen to be filled with fine-grained sediment and represents
a long strip of dark, organic-rich mud in a shelf otherwise largely covered by
very clean sands. At the eastern part of the study area lies a much larger
area of fine-grained sediments but which, unlike the Hudson Shelf Channel,
shows little or no bathymetric control of the fine-grained sediments. Com-
pared with Figs. 7, 8, and 12 to 14, these two patches of fine-grained sedi-
ments are seen to be the sources of both the suspended particles and the
excess radon in the lower portion of the water column. Vertical profiles of
both constituents show that, when thermal stratification of the water column
exists, vertical mixing of these bottom-source tracers is limited by the
thermocline. But under conditions of lower stability (as obtained during the
January 1976 cruise), both resuspended particles and excess radon are mixed
upward to the surface. The displacement of the plumes of these tracers from
their fine-grained sediment sources is a measure of the advective and diffu-
sive forces of dispersion acting in the water column on the shelf. Modelling
of these data in an attempt to quantify these dispersive forces is in progress
and will be the subject of another paper.
The problem of the zone of minimum near-bottom excess radon and suspended
particles is not answered from the sediment data (Fig. 15); if anything, it is
compounded. More than 100 samples of the sediment with a range of grain size
characteristics have been measured for their potential to produce excess radon
and these data show a correlation between radon productivity and the weight
percentage of the sample finer than 63 ym. The fine-grained sediments of the
aluminosilicates overwhelmingly dominate. This difference is shown in Fig. 6.
Discrete Ti (oxide) particles (a few microns in diameter) have been ob-
served at several depths in the Bight Apex near the disposal sites for sewage
sludge and acid Fe-Ti wastes. In addition, Fe and Ti coatings can be seen on
much of the suspended matter, including plankton (Fig. 1) in this area of the
Bight. Both the abundance of Fe- and Ti-coated and Ti (oxide) particles
decrease away from the Bight Apex, indicating their potential as tracers for
particle dispersal.
135
-------
74
U)
en
600
400-600
300-400
200-300
100-200
50-100
39
39
73
72
71
Figure 7, Concentration of suspended particles (pg/£) 10 meters above bottom (mab)
during October 1974.
-------
Ul
SUSPENDED PARTICULATE
CONCENTRATION
10 meters above bottom -
JANUARY 1976
>500
400-500
300-400
200-300
100-200
50-100
O<50
74 73 72 7\ 70
Figure 8. Concentration of suspended particles Cug/&) 10 meters above bottom (mab) during January 1976.
Note that the patch of high concentrations associated with the Hudson Shelf Channel in October
and July does not exist in January, but that the deeper water anomaly in the Upper Hudson Can-
yon remains.
-------
74
73
LJ
00
39
SUSPENDED PARTICULATE
CONCENTRATION
10 meters obove bottom \
JULY I975
39
74
72
71
Figure 9. Concentration of suspended particles
during July 1975.
10 meters above bottom (mab)
-------
74
73
SUSPENDED PARTICULATE
CONCENTRATION
(surface water)
JULY 1975
Ug/D
39
39
73
72
71
Figure 10.
Concentration of suspended particles (yg/£) in surface water during July 1975. Note
that both the 200 and 100 pg/Jl isopleths are nearer the coastline than at 10 mab
(Fig. 8). Note also that local high concentration anomalies at 10 mab such as those
adjacent"to the Hudson Shelf Channel and in the Hudson Canyon do not extend to the surface,
-------
74
73
I—I—f—I—I
SUSPENDED PARTICULATE
CONCENTRATION;
surface water
JANUARY 1976
>400
300-400
200-3OO
100-2OO
[X3 50-100
i I i I i
39h
74 73 72 71 70
Figure 11. Concentration of suspended particles (yg/£) in surface water during January 1976. Note that
the position of the isopleths are essentially the same as those for particulates 10 mab
(Fig. 9), suggesting that vigorous vertical mixing has homogenized the particulate populatioi
through the shelf water column.
-------
DISTRIBUTIONS OF SUSPENDED PARTICULATE MATTER AND EXCESS RADON
The distributions of suspended particulate matter and excess radon
discussed in this section must be viewed with the following limitations in
mind. First, the sampling on each cruise took place over a period of two
weeks and therefore, although assembled in a single figure, the data are not
strictly synoptic. We are aware of temporal variability in both particulate
and excess radon concentrations on the order of days or even hours. The
similarity of the gross features for data sets from three different seasons,
however, supports the validity of these general conclusions. Second, because
our paper focuses on near-bottom processes, the bottom, rather than the sea
surface, is taken as the reference level. This becomes a graphic convenience
because of the great depth range (10-3000 m) over which sampling was done on
each cruise.
The distributions of total suspended particulate concentrations at 10
meters above bottom are shown in Figs. 7, 8, and 9 for the October 1974,
July 1975, and January 1976 cruises, respectively. The principal, features are:
(1) a seaward decrease across the shelf in the concentration of particulate
matter; (2) localized patches of high concentrations of suspended particles
superposed on this general decrease most strikingly over the Hudson Shelf
Channel and Hudson Canyon. (The near-bottom localization of high concentra-
tions associated with the Hudson Shelf Channel [defined by the 55 m isobath]
in October [Fig. 7] and displaced southwest from it in July [Fig. 8] is not
evident in the January data set [Fig. 9]); (3) a zone beyond the shelf break
(>100 m water depth) approximately parallel to the isobaths near the bottom
that extends over about a kilometer of water depth in which the concentration
(or standing crop) of suspended particles goes through a minimum and, from a
limited number of data points, appears to rise again in deeper water. The
center of this zone is somewhere between the 1500 and 2000 m isobath.
These distributions of particle concentrations 10 meters above the bottom
may be compared to particle concentrations in surface water in July 1975 and
January 1976 (Figs. 10 and 11,respectively; surface samples were not taken on
the October cruise). During July, although the surface water concentrations
decrease seaward, they do so more rapidly with distance from shore than do
particulate concentrations near the bottom. At that time, some degree of
patchiness is seen in the surface-water concentrations but the locations of
patches of high concentrations bear no geographic relation to those seen near
the bottom. After comparing the January surface (Fig. 11) and near-bottom
data (Fig. 9), there is little difference in the distribution of concentra-
tions until beyond the shelf break. Beyond ^ 100-200 m water depth, as in the
upper continental slope have the greatest potential to produce excess radon
of any sediments in the study area rendering the near-bottom low-radon zone
over the slope at 1500 to 2000 m even more anomalous. Bottom photographs and
visual observations (Bruce Heezen of Lamont-Doherty Geological Observatory and
Wilford Gardner of Woods Hole Oceanographic Institution, personal communica-
tion) of this area show very clear water conditions underlain by very fine-
grained, almost soupy sediments. By direct observation, these sediments can
be easily resuspended if distributed by any mechanism.
141
-------
74
73
EXCESS RADON
10 meters above bottom
OCTOBER 1974
(dpm/IOOl)
39
39
71
Figure 12. Concentration of excess radon (disintegrations per minute, dpm/100 &) in water 10 mab during
October 1974. Note the coincidence of high concentrations of radon and suspended particles
on the shelf and low concentrations in the deep water zone along the upper continental slope
CFig. 7).
-------
74
OJ
EXCESS RA
10 meters above bottom
JULY 1975
(dpm/IOOl)
39
-39
74
72
71
Figure 13. Concentration of excess radon (disintegrations per minute, dpm/100£) in water 10 mab during
July 1975. Note the coincidence of high concentrations of radon and suspended particles on the
shelf and low concentrations in the deep water zone along the upper continental slope (Fig. 8).
-------
74
73
72
EXCESS RADON ,
10 meters obove bottom
JANUARY 1976
(dpm/IOOl)
39
74
Figure 14. Concentration of excess radon (disintegrations per minute, dpm/IOO&) in water 10 mab during
January 1976. Note that, although the zone of high concentration water associated with the
Hudson Shelf Channel is still visible in the January data, the concentrations of excess radon
are lower than in July (Fig. 13) or in October (Fig. 12).
-------
74
Figure 15. Distribution of percent fines (weight % < 63ym) in surface sediments.
-------
At present we see two possible, opposing explanations for our observa-
tions in this low-radon, low-particle zone. The first is that, despite many
casts in which our lower-most sample was taken within several meters of the
bottom, this zone of near-bottom water is so quiescent that the excess radon
being produced within the sediments and diffused across the sediment-water
interface is not mixed vertically more than a meter or so and we have missed
sampling the excess radon standing crop on several tens of casts. Comparing
this to excess radon measurements made elsewhere in the deep sea (1, 9, and
references therein) would indicate an area of extremely low vertical mixing.
Elsewhere, excess radon is observed to extend tens to hundreds of meters above
the bottom. The reason that this extreme quiescence, if true, is limited to
this depth range is not known. It does not coincide with any obvious hydro-
graphic parameters.
The second explanation is that some mechanism of horizontal mixing, act-
ing over one-half to one-kilometer depth, is exchanging the near-bottom
(excess radon-rich) water with mid-depth water from the oceanic interior that
would also be low in suspended particles (compared to water further up the
slope) and would contain no excess radon. Such mixing must be sufficiently
rapid to dilute the flux of excess radon from the sediments to undetectable
levels very near the bottom, but of a nature that does not stir up the bottom
sediments. We hope to be able to distinguish between these explanations as
the result of measurements to be made on future cruises.
Acknowledgments
We thank H. James Simpson and Taro Takahashi for reviewing this paper.
Financial support for this work was provided by the U.S. Energy Research and
Development Administration under Contract EY-76-S-02-2185. Lamont-Doherty
Geological Observatory Contribution No. 2501.
146
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REFERENCES
1. Biscaye, P.E., and S.L. Eittreim. 1974. Variations in Benthic,Boundary
Layer Phenomena; Nepheloid Layers in the North American Basin. In:
Suspended Solids in Water, R. Gibbs, ed. p. 227-260.
2. Biscaye, P.E., and S.L. Eittreim. 1974. Suspended Particulate Loads and
Transports in the Nepheloid Layer of the Abyssal Atlantic Ocean.
Marine Geology, v. 23, p. 155-172.
3. Biscaye, P.E., and C.R. Olsen. 1977. Suspended Particulate Concentra-
tions and Compositions in the New York Bight. In: Middle Atlantic
Continental Shelf and the New York Bight, M.G. Gross, ed. ASLO
Special Symposia No. 2, p. 124-137.
4. Brewer, P.G., D.W. Spencer, P.E. Biscaye, H. Hanley, P.L. Sachs,
C.L. Smith, S. Kadar, and J. Fredericks. 1976. The Distribution of
Particulate Matter in the Atlantic Ocean. Earth and Planetary Science
Letters, v. 32, p. 393-402.
5. Broecker, W.S. 1965. An Application of Natural Radon to Problems in
Ocean Circulation. In: Symposium on Diffusion in Oceans and Fresh
Waters, T. Ichiye, ed. p. 116-145.
6. Gross, M.G. 1972. Geologic Aspects of Waste Solids and Marine Waste
Deposits, New York Metropolitan Region. Geol. Soc. Amer. Bull.,
v.83, p. 3163-3176.
7. Lisitsin, A.P. 1972. Sedimentation in the World Ocean. S.E.P.M. Special
Publ. No. 17, Tulsa, Oklahoma, 218 p.
8. Meade, R.H., P.L. Sachs, F.T. Manheim, J.C. Hathaway, and D.W. Spencer.
1975. Sources of Suspended Matter of the Middle Atlantic Bight.
J. Sediment. Petrol, v. 45, p. 171-188.
9. Sarmiento, J.L., H.W. Feely, W.S. Moore, A.E. Bainbridge, and
W.S. Broecker. 1976. The Relationship between Vertical Eddy Diffu-
sion and Buoyancy Gradient in the Deep Sea. Earth and Planetary
Science Letters, v. 32, p. 357-370.
10. Schlee, J. 1975. Sand and Gravel. MESA New York Bight Atlas Monograph
21, New York Sea Grant Institute, Albany. 26 pp.
147
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TRACE ELEMENT GEOCHEMISTRY OF CONTINENTAL SHELF
WATERS OF THE SOUTHEASTERN UNITED STATES*
Herbert L. Windom
Skidaway Institute of Oceanography
P. 0. Box 13687
Savannah, Georgia 31406
INTRODUCTION
The greatest exploitation of the marine environment by man has occurred
on continental shelves. In the future, the search for mineral resources and
sites for nuclear power plants will focus greater activity in this region.
If the continental shelves are to be utilized in a logical way, with minimal
environmental impacts, it is important to understand processes that are active
there.
Most of the activities related to energy development (e.g., petroleum
exploration and production, offshore nuclear power plant siting) may result
in releases of stable and radioisotopes of naturally occurring trace elements.
To predict the fate of these additions and their ultimate impact on the
environment, we must develop a fundamental understanding of the natural pro-
cesses that govern their behavior. This paper discusses aspects of the geo-
chemistry of trace elements that influence their concentration and distribu-
tion in continental shelf waters. The trace elements considered are arsenic,
copper, mercury, nickel, and zinc. The discussion is based on studies of the
continental shelf of the southeastern U.S. coast, referred to as the South
Atlantic Bight (Figure 1).
The South Atlantic Bight is similar to most continental shelves in that
it receives runoff from the adjacent land and is bordered on its deep ocean
side by a strong boundary current (Gulf Stream). The hydrographic and chemi-
cal characteristics of a typical transect across the shelf are shown in
Fig. 2. Middle shelf regions are poor in nutrients, whereas the inner shelf
receives inputs from river runoff. Upwelling or intrusions from the Gulf
Stream, which occur along the entire South Atlantic Bight (1), supply nutri-
ents to the outer shelf.
*This research was supported by Grant E(38-l)890 from'the U. S. Energy
Research and Development Administration.
148
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FIGURE 1. The South Atlanttfc Blgh
ten major rivers/
84'
80'
Figure 1. The South Atlantic Bight and its 10 major rivers,
149
-------
DISTANCE OFF SHORE (KM)
10 30 50 70 90 HO 130 150
200J
145
DISTANCE OFF SHORE (KM)
10 30 50 70 90 110 130 150
200J
Ul
o
50
a. 100
UJ
o
150-
SALINITY %0
>36.25
50-
UJ
o
150-
20CK
SILICATE (jjmole/l)
Figuore 2. Hydrographic and chemical characteristics along a cross-shelf transect.
-------
Trace elements can be delivered to continental shelves by runoff,
atmospheric transport, and onshore intrusions of deep off-shelf waters
(Fig. 3) . By determining the magnitude of the trace element fluxes to con-
tinental shelf waters and comparing it to their total concentrations, it is
possible to calculate their residence times. The residence time then can be
compared to that of the water (both from intrusions and runoff) to determine
whether the elements behave conservatively,
Trace Metal Fluxes to Continental Shelf Waters
Rivers---Ten major rivers discharge into the South Atlantic Bight and
are responsible for the major portion of continental runoff. These drainage
basins are a mixture of crystalline igneous and metamorphic rocks and sedi-
mentary deposits. In general, each of the five trace elements studied do not
vary considerably in concentration from river to river (Table 1). Observed
variations probably relate to differences in the composition in the drainage
basins.
Only the dissolved phase of trace elements transported by rivers is
important to the continental shelf since the suspended load is deposited in
estuaries (6, 11). The dissolved components of arsenic, copper, and mercury
have been shown to be conservatively mixed through the estuary (9, 10); nickel
and zinc probably behave similarly. The conservative nature of these elements
during their transit through the estuary probably depends on their chemical
form. For example, arsenic in river waters primarily exists in the As(V) form
and is associated with low molecular weight organic matter (9). Copper also
appears to be complexed with organic matter. Nickel and zinc may behave
similarly but little is known of the form of mercury in estuaries.
Assuming that trace elements carried in solution by rivers is conserva-
tively mixed through the estuary, the total river input to the continental
shelf can be determined by summing the products of the mean concentrations
of the elements for each river and its discharge (Table 2). From these cal-
culations the relative importance of river transport for the trace elements
considered is Ni>Zn>Cu>As>Hg, which is the same general order as their relative
abundances.
Atmospheric Transport—Because of their proximity to the continents,
continental shelf environments may receive significant trace element inputs
due to atmospheric transport. Although it is difficult to measure atmos-
pheric trace element inputs directly, their atmospheric concentrations have
been used to deduce input rates (4).
Atmospheric concentrations of the five trace elements over the conti-
nental shelf of the South Atlantic Bight each vary by about an order of magni-
tude (Table 3). Much of this variation is undoubtedly due to the trajectory
taken by the air parcel sampled. Air transported directly from the continents
during offshore winds would clearly be expected to have higher concentrations
than that transported during easterly or onshore winds. Some of the varia-
tions in atmospheric trace element concentrations may also be due to exchange
of trace elements from sea surface to the air (4). Even with these uncer-
tainties, however, the mean atmospheric concentrations of the trace elements
151
-------
TABLE 1. GEOMETRIC MEAN RIVERINE TRACE ELEMENT
CONCENTRATIONS FOR SOUTHEASTERN UNITED STATES
River
1. Cape Fear
2. Pee Dee
3. Black
4. Santee
5 . Copper
6 . Savannah
7, Ogsechee
8. Altamaha
9. Satilla
10. St. John
(0.
(0.
(0.
(0.
(0.
(0.
(0.
(0.
(0.
(0.
As2
0.39
16-0.
0.21
08-0.
0.36
15-0.
0.15
04-0.
0.27
12-0.
0.30
13-0.
0.25
08-0.
0,21
04-0.
0,38
25-0.
0.49
26-0.
60)
32)
57)
31)
47)
47)
45)
47)
52)
72)
Cu
1.6
(0.1-3.
1.2
(0.1-2.
1.5
(0.2-2.
1.5
(0.4-3.
1.9
(0.9-3.
1.5
(0.4-3.
1.1
(0,2-2.
1.5
(0.3-3.
0.9
(0.1-2.
1.3
(0.1-2.
in soluti
yg/&l
1)
5)
1)
9)
4)
6)
0)
4)
6)
6)
(4.
(2.
(3.
(1.
(1.
(1.
(1.
(1.
(0.
(1.
Ni
8.0
0-15)
3.6
2-5.8)
5.8
0-11)
4.0
4-8.0)
5.0
4-11)
3,9
0-16)
4.1
0-7.5)
2.7
8-3.2)
2.6
7-3.5)
2.4
6-3.4)
(2
(1
(2
(1
(0
(0
(1
(I
(0
(1
Zn
6.2
.9-8
3.7
.6-4
5.2
.3-7
4.0
.4-6
2.7
.6-5
4.0
.5-8
2.8
.1-4
3.2
.6-6
.0)
,8)
.9)
.2)
.1)
.9)
,8)
.0)
7.5
.7-13)
5.9
.2-10)
ng/A1
Hg
24
(14-36)
20
(10-35)
20
(10-38)
18
(8-38)
18
(8-28)
21
(12-38)
19
(10-36)
19
(10-34)
19
(10-33)
39
(16-61)
range given in parentheses
I
'from Waslenchuk (9)
152
-------
Atmospheric Input
Runoff
Ul
U)
kilometers
GSW
0
10
20
30 £
40
Q_
^
Q
60
Figure 3. Schematic representation of trace element inputs to continental shelf waters.
-------
TABLE 2. ESTIMATED ANNUAL RIVER TRANSPORT OF TRACE ELEMENT
TO THE SOUTH ATLANTIC BIGHT
Element
Arsenic
Zinc
Nickel
Copper
Mercury
River transport
(kg/yr)
1.4 x 104
2 x 105
2.2 x 105
8 x Id4
1.1 x 103
TABLE 3. GEOMETRIC MEAN ATMOSPHERIC TRACE ELEMENT
CONCENTRATIONS AND INPUT TO CONTINENTAL
SHELF WATERS l
Element
AS3
Zn
Ni
Cu
Hg
No. of Mean Range Annual input 2
samples ng/SCM ng/SCM (105 kg)
11 1.6 0.2-6.3 0.2
17 8.9 3.4-24 2.9
17 1.4 0.2-4.8 0.4
17 3.0 1.0-16 0.9
42 2.1 0.3-7.6 0.6
Samples collected during summer and winter cruises.
2Using a dry deposition velocity of 0.26 cm/sec for As, 0.56 cm/sec for
Zn (Cumbray et al., 1975), and 0.5 cm/sec for Cu, Ni, and Hg, and assum-
ing the total atmospheric flux is 3 times the dry fallout.
Waslenchuk (9)
from air samples collected in the summer and winter can be used to ascertain
their annual input. Duce et al. (4) proposed a model that utilizes observed
dry deposition velocities for trace elements and to take into account washout,
assumes that the total atmospheric flux is 3 times the dry fallout. With this
model, the trace element input due to atmospheric transport can be calculated
for the entire continental shelf area (6 x 104 km2) of the South Atlantic
Bight (Table 3).
154
-------
Input due to Intrusions—The intrusion of deep Gulf Stream water onto
the shelf occurs frequently in the South Atlantic Bight. Details of these
intrusions have been described by Blanton (1). Along a given transect of the
continental shelf, intrusions occur about 13 times a year (Blanton and Atkin-
son, personal communication). The intrusions are identified by nutrient con-
centrations, salinity, and temperature; each excursion apparently displaces
1/5 of the shelf volume. The South Atlantic Bight continental shelf has a
volume of 1,920 km3. Thus, the annual volume of intruded waters to this area
is 4,980 km3.
The intrusions originate in the deep slope waters adjacent to continental
shelf and show elevated concentrations of the trace elements (Table 4). The
enriched trace element concentrations are apparently due to physical trans-
port of plant and animal detritus from the euphotic zone with subsequent
degradation and release of trace elements at depth. This process has been
described in several studies of deep ocean environments (2, 7, 3).
An estimate of the annual input of trace elements due to intrusions
can be made by multiplying the volume of intruded water by the concentrations
of the trace elements (Table 4). It is clear from this calculation that in-
trusions are the major mechanism of trace element transport to the continen-
tal shelf environment.
TABLE 4. ESTIMATE OF TRACE ELEMENT CONCENTRATION AND ANNUAL
INPUT IN INTRUSIONS
Concentration in Annual input
intrusion waters (10^ kg)
Arsenicl
Zinc
Nickel
Copper
Mercury
1.5 yg/£
0.61 Hg/£
0.61 yg/£
0.26 yg/£
25 ng/£
7.5
3.0
3.0
1.3
0.1
J-Waslenchuk (1977)
Trace Element Concentration and Residence Times in Continental Shelf Waters
The concentrations of trace elements in continental shelf waters vary
relatively little with depths and seasons (Table 5). Most of the As is in
the As(V) form with minor amounts existing as As(III) or dimethyl arsenic
acid (9). Little is known of the form of the other trace elements, but the
relatively high apparent complexation capacity of continental shelf waters
suggests that they may exist as complexes.
155
-------
TABLE 5_. TRACE ELEMENT CONCENTRATIONS IN CONTINENTAL SHELF WATER
Mean and standard Total content
deviation (kg)
2
Arsenic
Zinc
Nickel
Copper
Mercury
1.04 ± 0.19 Pg/£
0.49 ± 0.08 yg/&
0.49 + 0.06 ygA
0.16 ± 0.07 yg/£
20 ± 5 ng/SL
2 x
9.4 x
9.4 x
3.1 x
3.8 x
io6
5
10
5
10
5
10
io4
Assuming continental
of 32 m.
4 2
shelf area of 6 x 10 km
and an average
depth
TABLE 6. RESIDENCE TIME OF TRACE ELEMENTS IN CONTINENTAL SHELF WATERS
Residence time
Element (yrs)
Arsenic 0.27
Zinc 0.27
Nickel 0.29
Copper 0.22
Mercury 0.24
Excess
(mg/m2)
13
6
4.
3.
0.
3
5
35
Of the five trace elements studied, only arsenic appears anomalous in
that its excess cannot be reasonably accounted for by the three possible
removal mechanisms. As mentioned earlier, uncertainties in the data used for
these calculations are probably quite significant, particularly the uncer-
tainty in the determination of the concentration of trace elements in the
intruded waters. Our lack of detailed knowledge of the periodicity and vol-
umes of these intrusions may be the severest limitation on this approach.
Even so, the above discussion can give considerable insight into the rela-
tive importance of processes that govern trace element concentrations and
fates in continental shelf environments.
156
-------
The mean residence time of a given trace element in continental shelf
waters can be determined by the following equation:
T = CV
I +1 + I.
r a i
Where C is the mean trace element concentration, V is the shelf water
volume (1,920 km3) and Ir, Ia, and Ij_ are the annual inputs due to runoff,
atmospheric transport, and intrusions, respectively. Data from Tables 2
through 5 can be used to calculate the residence time for each of the five
trace elements. The residence times thus obtained (0.22 to 0.29 yrs.) are
remarkably similar (Table 6), but are significantly different from that cal-
culated for water (0.37 yrs.). If the trace elements behave conservatively,
their residence time should be similar to that of water. The fact that all
trace elements are less implies that an excess amount of each element is
transported onto the shelf, compared to that carried off. Even though the
uncertainties in the data used may be considerable, it is of interest to
calculate this excess (Table 6) to evaluate possible processes that may
result in losses in trace elements from shelf waters.
Sedimentation on the shelf is clearly a process of potential importance
in the removal of trace elements from the water column. The average shelf
sedimentation rate of the South Atlantic Bight is probably something less
than 0.1 mm/yr. This value can be used as an upper limit to calculate poten-
tial sedimentation losses of these elements. Assuming the sediment accumu-
lating has a trace element concentration similar to average carbonate sedi-
ments (8), and a density of 2.0 g/cc, the annual trace element loss would be
0.2, 7, 6, 6, and O.OOx mg/m2 for As, Zn, Ni, Cu, and Hg, respectively. For
zinc, nickel, and copper, this process accommodates tha excess amount deliv-
ered to the shelf calculated from the model described above. For arsenic
and mercury, however, it appears to be an insignificant removal mechanism.
Primary production on the shelf is the major source of particulate
carbon in this environment. The average annual production for the entir©
shelf has been estimated at 170 gC/m2 (5). This would amount to an annual
production of approximately 300 g/m2 of total particulate organic matter.
If the organic matter has concentrations of trace elements approximately
equal to that of phytoplankton (20 ppm Zn, 10 ppm As, Cu, and Ni and 0.1 ppm
Hg), then annually 6 mg Zn/m2, 3 rag As, Cu and Ni/m2, and 0.03 mg Hg/m2 could
be removed from the dissolved phase. Assuming the trace elements are not
regenerated on the shelf, this removal mechanism could be of significance
for all but mercury.
A large portion of the trace elements delivered to continental shelf
waters by atmospheric transport may be inorganic particulates. If we assume
that all atmospheric input is of this nature, and does not contribute to the
soluble trace element content of shelf waters, the amounts of the excesses
for which this could account are 0.3, 4.8, 0.6, 1.5, and 1.0 mg/m2 for As,
Zn, Ni, Cu, and Hg, respectively. This mechanism could account for the
apparent excesses in zinc and mercury delivered to the shelf.
157
-------
REFERENCES
1. Blanton, J. 1971. Exhcange of Gulf Stream Water with North Carolina
Shelf Water in Onslow Bay during Stratified Conditions. Deep-Sea
Res., 18: 167-178.
2. Boyle, E. A., and J. M. Edmond. 1975. Copper in Surface Waters South
of New Zealand. Nature, 253:107-109.
3. Boyle, E. A., F. Sclater, and J. M. Edmond. 1976. On the Marine Geo-
chemistry of Cadmium. Nature, 263:42-44.
4. Duce, R. A., G. L. Hoffman, B. J. Ray, I. S. Fletcher, G. T. Wallace,
J. L. Fasching, S. R. Piotrowicz, P. R. Walsh, E. J. Hoffman,
J. M. Miller, and J. L. Heffter. 1976. Trace Metals in the Marine
Atmosphere: Sources and Fluxes. In: Marine Pollutant Transfer,
H. L. Windom and R. A. Duce, eds. D. C. Heath, Lexington, Massachu-
setts, 77-120.
5. Haines, E. B., and W. M. Dunstan. 1975. The Distribution and Relation
of Particulate Organic Material and Primary Productivity in the
Georgia Bight, 1973-1974. Estuarine Coastal Mar. Sci., 3:431-441.
6. Meade, R. H. 1969. Landward Transport of Bottom Sediments in Estuaries
of the Atlantic Coastal Plain. Jour. Sed. Pet., 39:222-234.
7. Sclater, P. R., E. Boyle, and J. M. Edmond. 1976. On the Marine Geo-
chemistry of Nickel. Earth Planet. Sci. Lett., 31:119-128.
8. Turekian, K. K., and K. H. Wedepohl. 1961. Distribution of the Elements
in Some Major Units of the Earth's Crust. Geol. Soc. Am. Bull., 72:
175-192.
9. Waslenchuk, D. 1977. The Geochemistry of Arsenic in the Continental
Shelf Environment. Ph.D. Thesis, Ga. Inst. Tech. 62 pp.
10. Windom, H. L. 1975. Heavy Metal Fluxes through Salt-marsh Estuaries.
In: Estuarine Research (L. E. Cronic, ed.), Vol. 1, Academic Press,
137-154.
11. Windom, H. L. , W. J. Neal, and K. C. Beck. 1971. Mineralogy of Sediments
in Three Georgia Estuaries. Jour. Sed. Pet., 41:497-504.
158
-------
THE FLAMELESS ATOMIC ABSORPTION METHOD FOR MERCURY DETERMINATION
AND ITS USE IN CONTROLLING ENVIRONMENTAL POLLUTION
N. S. Poluektov and Yu. V. Zelyukova
Institute of General and Inorganic Chemistry of the
Academy of Science of the Ukrainian SSR Odessa Laboratory
Because of the wide use of mercury in industry and agriculture in the
last decade, we have seen its presence increase in environmental pollution.
The yearly production of mercury from natural sources and industry is now
estimated at about 30,000 tons. Therefore, it is necessary to establish some
sensitive, selective, and rapid methods of mercury determination for the sys-
tematic control of its content in nature, particularly near large industrial
centers.
We propose a method developed by the authors of no-flame atomic absorp-
tion for mercury determination (1) based on easy passage of mercury from
aqueous solution to a gas phase after its reduction to metal. Fig. 1 shows
a diagram of the device used in our work.
Optical density of mercury vapor, obtained from an analyzed solution by
air stream or inert gas after mercury is reduced to metal, is measured at
A=253,7 nm. A tin chloride solution was used originally as the reducer.
The possibility of other reducers (sodium stannite, ascorbic acid, formalde-
hyde) was also investigated. These reducers help to remove some interference
that occurs when using tin chloride in acid medium (2 to 4).
Sensitivity of the measurement on criterion 2? is equal to 6.10~4 meg Hg
in analyzed solution with optimal parameters, set by the authors (speed of
the air stream, 3 ml per second; analytical cuvette, 50 cm; d, 1 cm; the dur-
ation of the measurement, 1 to 2 minutes).
Tin Chloride—When using tin chloride, the majority of metals (K, Mg, Na, Cs,
Be, Ca, Ba, Cu, Zn, Al, P , Mo, Ni, Mn, Fe) present in the analyzed solution
have no influence on the determination of mercury. The majority of inorganic
acids, with a concentration of 2 N, have no influence on the final results.
Sulfides, however, have great influence because of formation of the insoluble
precipitate, HgS. Metal ions, reduced to the elementary state and reacting
with free mercury with formaton of amalgams (Ag, Au, Pt), prevent the trans-
fer of the free mercury to the gaseous state. As determined with the method
of the isomolar series, the compounds of selenium and tellurium are present
in solution form with mercury selenides and tellurides. The ions of iodine,
bromine, and fluorine prevent the determination of mercury.
159
-------
Figure 1.
Diagram of the device for mercury determination by the method of
atomic absorption in the gas phase: (I) current source FEU; (2)
spectrophotometer SF-4, (3) lamp BUV-15, (4) microamperemeter,
Q °T! ^' (6) calcium ^loride tube, (7) trap, (8) test tube,
(9 grinded nozzle, (10) clamp, (11) rheometer, (12) photomulti-
X~ J--L€3T •
160
-------
Ascorbic Acid—As the reducer in mercury determinations, ascorbic acid makes
possible the exclusion of the influence of halogens.
Formaldehyde—Reducing mercury does not reduce selenium and tellurium ions,
thus making it possible to use this method for mercury determination in selen-
ium and tellurium preparations. The method used corresponds to demands being
made for the analysis of environmental pollution. It is widely used in the
USSR and abroad (5 to 8). However, certain authors who used this method have
described it without referring to our works (9 to 10).
Some of our methods of mercury determination in environment are des-
cribed below.
Mercury Determination in Natural Water
The above indicated sensitivity of determination is not sufficient for
mercury determination in natural waters. We used the rapid method for pre-
liminary concentrating that increases the sensitivity more than two magnitudes
of value. Mercury in l£ of water first was reduced with tin chloride. It was
then absorbed with a 3 ml 0, 01 N iodine solution by educing from the sample
with a stream of inert gas. In its concentrate, mercury was determined, by
using a 0.2 ml 10 per cent solution of ascorbic acid as the reducer which was
transported as aerozole for bonding of the free iodine vapor. The amount of
reduced mercury is equal to 96 or 97 per cent. The minimally discoverable
amount of mercury through concentrating one time is 8.10"^ meg Hg. Further,
increased sensitivity can be achieved from several samples of water by using
one absorbing solution. Required time for this analysis is 7 minutes.
Mercury Determination in Air
A method of mercury determination in the air was also developed. It
consists of absorbing mercury vapor from air with a 0, 01 n. iodine solution
by passing a volume of air through the solution. The absorbing mixture is
determined, by using ascorbic acid as a reducer as previously stated.
Required time for this analysis is from 4 to 16 minutes, depending on
the mercury concentration in the air.
The outlined methods were used for analysis of natural waters of the
northwestern region of the Black Sea to determine human and industrial
effluents in the water and atmosphere (11 to 13).
161
-------
REFERENCES
1. Bazhov, A.S., Ye. M. Yemelyanov, and Yu. O. Shaidurov. 1972. Atomic
Abcorbtion Determination of Mercury in Waters of the Atlantic Basin.
Isledovaniyev Oblasti Khimicheskikh I Fizicheskikh Metodov
Analiza Mineralnogo Syrya (Research in the Field of Chemical and
Physical Method for Analyzing Mineral Raw Materials), Issue 2,
pp. 186-192.
2. Balashov, A.I., Yu. V. Zelyukova, and N.S. Poluektov. Mercury Content
in the Northwest Part of the Black Sea. Okeanologiya, (in press).
3. Vitkun, R.A., Yu. V. Zelyukova, and N.S. Poluektov. 1974. Atomic
Absorbtion Determination of Mercury. Zabodskaya Laboratoriya
(Factory Laboratory), Vol. 40, No. 8, pp. 949-951.
4. Vitkun, R.A., Yu. V. Zelyukova, and N.S. Poluektov. 1974. Flameless
Atomic Absorption Determination of Mercury in Selenium and
Tellurium Preparations and the Use of Formaldehyde as a Reducing
Agent. Ukrainean Chemical Journal, Vol. 40, No. 12, pp. 1304-1307.
5. Vitkun, R.A., T.B. Kravchenko, Yu. V. Zelyukova, and N.S. Poluektov.
1975. Atomic Absorption Determination of Mercury in Waters.
Zavodskaya Laboratoriya, No. 6, pp. 663-665.
6. Vitkun, R.A., N.S. Poluektov, and Yu. V. Zelyukova. 1974. Ascorbic
Acid as a Reducing Agent in the Flameless Atomic Absorption
Determination of Mercury, Zhurnal Analiticheskoi Khimii, Vol. 29,
No. 4, pp. 691-694.
7. Zelyukova, Yu. V., R.A. Vitkun, T.B. Kravchenko, and N.S. Poluektov.
1976. Atomic Absorption Determination of Mercury in Air.
Gigiena I Sanitariya (Hygiene and Sanitation), No. 1, pp. 66-68.
8. Poluektov, N.S., R.A. Vitkun, and Yu. V. Zelyukova. Determination of
Milligram Quantities of Mercury by Atomic Absorption in the
Gaseous Phase. Zhurnal Analiticheskoi Khimii, Vol. 19, No. 8,
pp. 937-942.
9. Hatch, W.R.,and W.L. Ott. 1968. Determination of Sub-microgram of
Mercury by Atomic Absorption Spectrophotometry. Anal. Chem.,
Vol. 40, No. 13, pp. 2085-2087.
10. Kirkbright, G.F.,andM. Sargent. 1974. Atomic Absorption and Fluores-
cence Spectroscopy. Academic Press, London, New York and
San Francisco, p. 638.
162
-------
11. Manning, D.C. 1970. Flameless Methods for Mercury Determination by
Atomic Absorption (a Review). Atomic Absorption Newsletter,
Vol. 9, No. 5, pp. 97-99.
12. Wilson, A.L. 1974. The Chemical Analysis of Water, London, p. 96.
163
-------
THE SCIENTIFIC PRINCIPLES OF THE PROBLEM
OF SEAWATER POLLUTION
A. I. Simonov and A. N. Zubakina
State Oceanographic Institute
Moscow
The object of scientific study of the problem of seawater protection
from pollution consists of development of valid recommendations for the
regulation of waste release under which the processes of natural utilization
of harmful substances must continuously prevail over pollution. The result
should be the elimination, if possible, of disturbances in the marine environ-
ment and faults in the ecological system. This definition covers many ques-
tions, some of the more important questions are: 1) the systematic evaluation
of pollution of seawaters and its influence on the natural physical-chemical
and hydrobiological conditions, 2) studying the ways and parameters of dis-
tribution and utilization of pollutants for subsequent definition of the
possible regulation of pollutant release into the sea, 3) the development of
recommendations on optimal regulations of releasing pollutions in the ocean
and sea areas, and 4) prediction of pollutant dynamics of seawaters for pre-
sent and future perspectives on the set values of waste release and known
hydrometerological, hydrochemical, and hydrobiological conditions (6).
The difficulty of making decisions on the above questions is determined,
firstly, by the complexity of the subject itself as it touches on many areas
of living and non-living matter which predetermines the complicated and inter-
disciplinary character of fields of oceanographical, biological, chemical,
geological, climatological,and other sciences. And, secondly, the amount and
direction of oceanography demands on the significant developments for solving
this problem.
Observations of pollution, starting in 1965, were made systematically in
the seas of the Soviet Union by the Hydrometsurvice under the scientific and
meteorological guidance of the State Oceanographic Institute. The observa-
tions have now spread over many areas of the North Atlantic and Pacific
Oceans.
Investigation of pollution in the North Atlantic by the scientific
research weather ships Shkval and Musson were made in 1972 and 1974. The
main steps of Soviet Oceanographic investigations on pollution problems began
in 1971 with three successive cruises of the scientific research weather ships
Poryv, Shkval, and Vikhr in seawaters adjacent to Europe (3,7). These
observations allow us to make some extremely important conclusions on the
nature of the phenomenon itself, and on the pollutant's influence on the
substantive composition of seawater.
164
-------
The most important conclusion from these investigations is that pollution
has a global character. At present the most dangerous pollutants are oil, oil
products, compounds of heavy metals, mercury, lead, and the pesticides DDT,
DDE, ODD, and HCH. According to the International Convention on the Preven-
tion of Seawater Pollution by wastes and other harmful substances, adopted in
1972, these pollutants are prohibited in general from being released in the
sea, but are observed equally in interior waters and even in some areas of the
open ocean. The pollution fields, as a rule, are generated near the coasts,
but spread far from the boundaries of the coastal areas, covering many seas.
(They are stable in time and space.
Releasing pollutants, on the one hand, results in decreasing oxygen pro-
duction and, in some cases, in decreasing intensity of oxidation of organics.
On the other hand, a sharp decrease in oxygen content that is spent on the
oxidation of organics is noted. In semi-enclosed seas (e.g. the Baltic Sea),
pollution results in a strong deficiency of oxygen, and in the complete ab-
sence of oxygen in lower layers. In open tidal seas, however, (e.g. the North
Sea), an oxygen deficiency is also observed. This, in turn, results in
accumulation of intermediate oxidation products, such as ammonium. In the
Baltic Sea the ammonium content is sometimes more than 30 to 40 years old (6) .
Another important conclusion from these investigations is the finding of
a significant influence of chemical pollution on the primary production of
oceanic waters. It is known that the warm waters of the Gulf Stream are
characterized by relatively low productivity. It was confirmed by samples
obtained during the Musson cruise that chlorophyll is distributed in the sur-
face layer. In the open ocean, chlorophyll content was insignificant, varying
from 0 to 0.05 g/i, in general, and only now and then rising to 0.1-0.2 g/&
(in waters of the North Atlantic current). With such a level of primary pro-
ducation it is practically impossible to understand the degree of influence of
chemical pollution on chlorophyll.
In the area of the North American continental shelf, the chlorophyll
content was noticeably higher (0.1-1.0 g/£). Estimating the influence of
chemical pollutants on the primary productivity of surface waters, it should
be noted first, that in the southern part of this area, where mercury concen-
trations were small, the maximum concentrations of chlorophyll were observed.
Pheophytin (its degradation product) was completely absent. This is likely
the indication of the pollutant's effects on the primary production of phy-
toplankton during vegetation.
In the northern part of this area, including Georges Bank, where sea-
water was most polluted by mercury, oil products, and detergents, the
chlorophyll content was considerably lower (generally to 0.1 g/£), but the
pheophytin content was sharply increased (to 2-3 g/H). The high concentra-
tions of the chemical pollutants do not inhibit and depress the photosynthe-
sis process in weeds as they ruinously influence living organic matter gener-
ated during this process. It is clear that pheophytinization takes place
under common conditions; also it takes place during natural dying off of the
living cells of phytoplankton. In some areas, as on the Georges Bank, it can
take place only during an extremely unfavorable phenonema for plankton pro-
duction such as heavily polluted waters. The process of chlorophyll degrada-
tion and pheophytin formation was much more intensive in Man Bay.
165
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So, the fact that chemical pollution significantly influences sea-
water's primary production can be considered true.
Finally, the third very important conclusion relates to the role of the
main circulation systems and relatively stagnant areas of the seas and oceans
in the transport and accumulation of pollutants.
For example, consider the system of the North Atlantic current. It
should be noted that it plays an extremely important role in the transport
of oil products and other pollutants and that its currents, being saturated
near the coasts of North America and Europe, have some relief areas. These
include the Sargasso Sea, the Barents Sea, and, likely, also the Norwegian
Sea. So, the relatively stagnant areas become gigantic accumulators of harm-
ful substances (7) .
The identification of the global, character of seawater pollution suggests
the importance of clear determination of perspectives for subsequent investi-
gations and development of a global system of observations of seawater pollu-
tion. While improving the system of pollution observation, great attention
should be paid to the questions of self-purification, the calculations of
pollutant balance, and development of recommendations on regulation of opti-
mal conditions for dumping pollutants.
The diagram of pollutant balance can be briefly and quantitatively
expressed as follows (6) :
Act= (CM-C'M')[V + (M-MV)]=[ (C m +C m +C m +
.L J_ £t & «J J
: (V+Zm) .
In this equation, unknown components of income and outflow of pollutants
can be added to the right side:
Act - is increasing the pollutant concentration for the period of time
in the sea, or its part with water volume V;
CM and C'M' - is the quantity of incoming pollutant from all sources and
utilized in different ways, where C and C1 are the con-
centrations, M and M1 are the water volumes by which the
pollutants are transferred through the sea boundaries or
its parts;
Clmi ~ the amount of pollutant coming from the shore, (C.m =
Cl.A.l+C1.2^2+C1.3ml.34<:i.4mi.4+C4.5ml.5'
the right side of which reflects, correspondingly, the
pollutants being added by river systems, dumped from the
shore, discharged by sewer systems from the towns, flowing
in from storm runoffs and by tidal action;
166
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C2m2 ~ the pollutant quantity, incoming from mining on the shelf
^C2.1m2.1^' from tne °il drilling platforms (C2.2m2.2^>' from
transportation losses (C2 3m2 3), and from discharge water from
ships (C2>4m2>4);
C3m3 and C3m3 ~ inflow (outflow) during water exchange between the seas;
C4m4 and C^m4 - inflow (outflow) of pollutants at the air-water interface;
C5m5 and C£m£ - inflow (outflow) of pollutants at the interface of solu-
tions and on suspended particles (C5 1m5 ^) , and with
organisms (C5 2m^ 2);
C6m6 and C6m6 ~ dynamical inflow (outflow) of pollutants from one area
into another; C6ni6=C6>1in6>1-K:6i2in6.2+c6.3in6.3-K:6.4in6.4'
where the right side correspondingly reflects inflow with
advection, turbulence, organisms, and ice.
- pollutants incoming as an intermediate product of degradation of
other pollutants;
- pollutant decrease under the chemical and biological degradation;
- pollutant decrease accumulated in hydrobionts.
The following conditions should be imposed to equate for the variations
of environment:
0 < C < I LPC and AC <_ 0,
where LPC is the limited permissible concentration of pollutant.
If this equation is solved relative to pollution of an ocean or sea, as
a whole, the terms Cgmg and C£m^, reflecting the dynamical redistribution of
pollutants between individual areas, can be omitted.
With this balance diagram in mind it is possible to po.int out the main
direction of further investigation, related to development of scientific
principles and an observational system of pollutant dynamics. Let us consi-
der these questions, applying them in general to oil and oil products as the
most widespread of pollutants.
During study of the balance of components of oil pollution, it becomes
evident that the calculation of their input by different ways is most time-
consuming. The ways and means of harmful substance input can be direct and
indirect.
The direct means of oil and oil product input includes the leakage or
catastrophic release during drilling on the shore or shelf, transport acci-
dents, discharge of washing waters and wastes from oil refining and repro-
ducing plants into the sea. Generally, it is possible to test and assess the
discharge of wastes, including oil products and leakage of oil, during
167
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drilling. It is not difficult from a scientific standpoint. Assessment of
catastrophic spills of oil during drilling and transportation should be based
on statistical data.
Studying and assessing oil and oil product input by indirect ways, (i.e.
from river systems, channels, from the atmosphere, and so on) which are
likely the most powerful sources of sea water pollution, is another matter.
The methodical principles of studying the discharge of oil pollution
through river systems are, firstly, that oil and oil product concentrations,
unlike the natural components of chemical composition, do not depend on the
value of total water runoff. Secondly, that the maximum oil pollution dis-
charge must correspond to the time of the greatest storm runoff and surface
water flow. This requires systematic observations of oil pollution concen-
trations dynamics at the heads of deltas and in the outlets of the delta
branches. In determining the sampling frequency, it is necessary to take
into account that oil, and any other pollution, can be discrete in time and
in space. Thus, sampling should be made frequently on the whole river cross
section.
Thus, organization for observations of oil pollution discharge by river
systems is time-consuming and expensive. Because of this, reliable informa-
tion on the rates of these discharges is not available in source literature.
At the same time, judging by the regular infrequent observations made on some
rivers, oil pollution inflow by river is one of the valuable components of
the input part of the balance. So, an approximate calculation shows that in
the Black Sea, river runoff brings 28.7 per cent of oil pollution annually
(including 23 per cent from the Danube).
The calculation of input, and removal of pollutants during water exchange
between the seas, can also make up a considerable part of the input part of
sea pollution balance. So, in the Black Sea, the inflow of oil pollution,
through the channels, is equal to 12.8 per cent of the whole inflow, including
4.2 per cent through the Kerch Channel, and 8.6 per cent through the Bos-
phorus. In the Baltic Sea, 15 per cent of hydrocarbons of oil origin annually
come through the Denmark Channels.
The examples given above reveal the serious importance of the streamflow
and the water exchange as a method of significant pollution of a semiclosed
sea. It can be seen that inflow of oil pollution by rivers and channels
exceeds 40 per cent of the total income.
Naturally, the question arises, by what ways do the rest of the 50 to
60 per cent pollution reach the sea? As mentioned above, they can reach the
sea directly. But this result would include the input from the atmosphere.
Unfortunately, the estimate of this input was not made, either experimentally
or theoretically, in a scientific way. Some theoretical or numerical calcu-
lations, insufficiently confirmed by experiments, probably give extremely
overestimated results. For example, according to the data of American inves-
tigators, the transfer from the atmosphere to the ocean is estimated at ten
millions of tons annually. The calculations of oil product input from the
surface of the Black Sea, made on a small series of determinations of oil
168
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hydrocarbons in the precipitations, probably gave an overestimated value.
This inflow was equal to 37 per cent of the total input of pollutants. Com-
parison of input and expenditure of the pollution balance for the Black Sea,
including the inflow from the atmosphere, suggests that input exceeds the
expenditure by more than 30 per cent. Under these conditions, two alterna-
tives can be assumed: either the inflow of volatile fractions to the atmos-
phere balances their inflow (which is unlikely) or there are serious methodi-
cal mistakes in determination of pollution inflow from the atmosphere.
It seems, therefore, that investigation of oil pollution balance should
be made simultaneously in three directions:
1. The integral estimate of the destruction processes and inflow of
pollution on the dynamics of pollutants level, including destruction rate.
2. Studying of pollution inflow by river systems and inflow-outflow
through the channels to differentiate the input components in calculations of
the above.
3. Studying the inflow-outflow of the sea surface for the same purpose.
The balance, connected with natural utilization of pollutants, is the
most difficult problem. Solving of pollution balance is generally impossible
without understanding of mechanisms and rates of their degradation. These
depend on many factors, and should be investigated at the same time in labora-
tories and in the field (4,5).
It should be noted that the oxygen content, the temperature conditions,
etc., greatly influence the degradation rate of oil products and other pollu-
tants. With an oxygen deficiency, and the temperature below 10° to 15°C, the
degradation rate decreased sharply and the accumulation process prevailed
over oil product degradation. This situation can be illustrated by the
variations of oil product content in the waters of an interior sea (Fig.l). It
is characteristic that during two months (April to June) the oil product con-
tent decreased by 67 per cent; then, from June to August, the degradation rate
decreased but the oil concentration decreased by only 13 per cent. As a
whole, the oil product content decreased 80 per cent from April to August.
This suggests the significant capacity of the sea for selfpurification. But,
in October, when the water temperature and degradation rate decreased con-
siderably, the oil product content began to rise.
The analyses of the experimental data and field observations allow us to
express, in rough approximation, the equation of oil product balance as:
-kt
ACt = (Ct-1 + K C) e
where ACt is the increase of oil product concentration for the period of t,
and is equal to Ct-l-Ct, KG, (increase in the same period of time, including
a decrease because of outflow into another sea, and evaporation to the atmos-
phere), k - the constant of reaction rate.
169
-------
100
50 •-
•H
O
100%
37%
13%
80%
IY
YY
YI
YII
YIII
Time
Figure 1. Variations in content of oil products in interior sea.
The balanced equation can be used for calculation of dynamic levels of
sea pollution for near and remote perspectives.
It is easy to use and test the calculation diagram, suggested above, on
such examples as the North Sea, the Baltic Sea, the Black Sea, and others,
under conditions of reliable calculations of mean concentrations of oil and
oil products in the whole sea, and in layers. Correctness of the calculation
of the ACt value can be estimated on the dynamics of mean concentrations cal-
culated from observational data. In this equation the description of degra-
dation kinetics of oil and oil products is the most vulnerable. We shall see
below that, strickly speaking, it cannot be approximated by a formal kinetic
equation of the first order.
The processes of natural selfpurification are conditioned by hydrocarbon
composition of oil and oil products, and specific features of the water basins
with different physical-geographical conditions.
The chemical composition of hydrocarbons of oil origin in seawater is
the main question in the complex problem of investigation of destruction pro-
cesses of oil and oil products. Therefore, the main attention of investiga-
tors is concentrated on the determination of non-polar and small-polar hydro-
carbons.
As our investigations showed, the combination of infrared spectroscopy,
gas-chromatography, and fluorescence-indicator methods, allows us to under-
170
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stand the composition of hydrocarbons, separated from the seawater and ice.
Experimental investigations made in coastal arctic waters revealed prevailing
paraffin-hephthene hydrocarbons in water and ice samples, and a difference
between the quality composition of hydrocarbons in ice and seawater sampled
at different depths (Fig. 2). It is possible to affirm, that in the ice
samples, the maximum peaks of hydrocarbons lies among C H -C H , and the
traces of light hydrocarbons are marked. On the chromatograms of water sam-
ples taken from near the bottom layer, the peak maximum moves to the low
temperature area of the chromatogram and includes hydrocarbons C H -C H .
The concentration of paraffin-naphthene hydrocarbons, obtained by boiling
at high temperature, is insignificant.
The presence of light hydrocarbons (cyclohexane, ethylcyclohexane,
methylcyclohexane, and nonane) is likely because hydrocarbons with low molec-
ular weight are not especially volatile at negative temperatures.
Information available from present literature is concerned with the com-
position of n-alkanes in the surface waters of the coasts of Bermuda, the
Gulf of Mexico, the Caribbean Sea, East and North Atlantic, the Persian Gulf,
the Greenland Sea, the Mediterranean Sea, and the Indian Ocean. Investigations
made in the above mentioned areas showed the presence of n-alkanes, generally
from C to C , with a maximum content of C -C in East Atlantic waters,
and C j--C in waters of the Gulf of Mexico. Hydrocarbons in oceanic waters
were found to be complicated mixtures, including the saturated and aromatic
compounds with the atomic number of carbon in molecules from 14 to 32.
Based on the data of all the above mentioned authors, and taking into
account the wide spectrum of molecular weights for hydrocarbons isolated from
water and ice, it is possible to determine that the hydrocarbons found origi-
nate from oil. As the hydrocarbons, isolated from water, ice, and dieseloil of
the survey area, have the same group composition, the diesel oil was taken as
substratum for studying hydrocarbon oxygen characteristics. As n-paraffines
in diesel oil and seawater samples prevail, ability of oil-oxydizing bac-
teria to oxidize the mixture of alkanes including C , C , C , C , C ,
C,Q, C , C , and cyclohexane, was studied (1,8).
In investigating the processes of hydrocarbon oxidation, the most atten-
tion was paid to a study of the temperature influence (the main factor of
chemical and microbial genetics) on their quantitative and qualitative vari-
ations. The temperature range of -0.3to0.6°C, +2°C, +10°C, +20°C was
selected.
Analyzing the results of chemical and bacterial oxidation of hydrocarbons
of diesel oil and n-alkanes, obtained at different temperatures, it is possi-
ble to affirm that bacterial oxidation of diesel oil by hydrocarbon-oxidizing
bacteria, isolated from water and ice, is active at the temperature +20°C.
This fact was noted by many investigators in different areas of the world's
oceans.
At the same time, at temperatures near 0°C, when chemical oxidation is
reduced, the bacterial oxidation of hydrocarbons increases significantly
(Table 1). In consideration of the ratio of the chemical and bacterial
171
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TABLE 1. KINETIC CHARACTERISTICS OF THE PROCESSES OF CHEMICAL AND BACTERIOLOGICAL OXIDATION OF DIESEL
OIL HYDROCARBONS AND N-ALKANES.
Diesel Oil
n-aJJcanes
C -
12
C, .
14
C,,
16
_
19
C
2O
1°C
+20
+10
+2
-O. 3 -0.6
+20
+10
+2
+20
+10
+2
+20
+10
+2
+20
+10
+2
+20
+10
+2
Co.mg
760
1958
2200
2.36
60
45.4
92.5
27.6
14.8
33.2
15.9
12.1
32.6
2.7
11.1
17.8
2.7
2.4
13.1
C-,
Chem.
700
78
40
0
9
8.1
4.9
1.6
12.8
1.2
9.1
mg
Bacter.
730
985
780
0.92
54.6
8.9
12.5
25.5
5.3
11.2
13.9
3.1
7.6
2.5
6.1
17.8
2.5
2.4
13.1
oxidation % K2» IT-Mng-day"1 Ki,day"l
Chem.
13.2
3.9
1.8
0
15
5.1
0
29
8.1
0
31
4.1
0
59
10.7
71.9
44
0
69.4
Bacter.
96
50.3
35.4
38.9
91
20
13.5
92
35.8
33.7
87
25.6
23.8
92
54.8
100
92
100
100
Chen.
0.015
0.012
O.OO3"
0
O.168
0
O
0.172
0
0
0.178
0
O
1.646
0
0.045
1.313
0
0
Bacter.
0.002
O.OOO
0.000
0.724
0.018
0.066
O.015
0.035
O.244
0.017
0.10
0.246
O.167
0.632
0.099
0.008
0.508
0.699
0.031
Chem.
0.078
0.000
0.013
0
0.177
0
0
0.032
0
O
0.033
0
0
O.OO3
0
0.005
0.026
O
0
Bacter.
O.036
0.177
O.O33
O.O3S
O.075
O.O26
0.114
O.159
O.OO4
O.O20
O.078
O.O13
O.O48
0.073
0.059
0.078
0.123
O.064
O.O38
W, day"1 HiC",mg
Che».
1.548
0.936
O.145
O
1.689
0
0
1.42
O
0
1.86
0
0
2.64
O
O
1.60
O
0
Bacter.
1.496
O.571
0.189
O.702
1.O57
O.614
0.30O
1.O27
O.496
0.21O
1.46O
O.778
O.427
1.650
0.663
O.23
1.39
O.9O5
O.44S
Chem.
7.8
0.031
0.52
O
1.59O
O
O
O.26
O
O
0.16
O
O
O.OO4
O
O
O.O31
O
O
day-1
Bactfcr.
26.9
174.34
25.74
O.3Z2
4.09
0.231
1.425
4.O5O
0.0081
0.224
1.O8O
O.O4O
0.365
0.180
O.359
1.388
6.01
O.1S4
O.498
-------
B
T°
• i
Figure 2. Gas chromatograms of hydrocarbons from ice (A) and water from
under-ice (B) and near-bottom (C) layers.
173
-------
'24
20
"24
T°C
Figure 3. Gas chromatograms of bacterial, A,B,C,D, (individual culture) and
chemical, A,, B^, C]_, D]_, oxidation of an n-alkane mixture at +20°C.
A]_, in 0 hr, A,A]_, in 24 hr, B,B]_ in 48 hr, C,C]_, in 72 hr, D,D]_,
in 96 hr.
174
-------
Figure 4.
Gas chromatograms of bacterial A, B, C, and D (culture mixture) and
chemical A:
20°C. A
1'
-
in
V
and
oxidation of n-alkanes mixtures, at
and D,D]_ in 96 hr.
hr, A,AI, in 24 hr, B,B]_, in 48 hr, C,Clf in 72 hr,
175
-------
oxidation of diesel oil hydrocarbons in all experiments made, the original
course of the process was revealed. Oxidation of diesel oil is caused gener-
ally by bacterial factors, whose role increases gradually with the time of
exposure at +20°C. The role of bacterial oxidation processes at +10°C
increased sharply on the second day of the experiment, and at +2°C, it
decreased sharply on the seventeenth day. Under conditions of destruction
of the n-alkanes mixture, the role of the chemical oxidation increased con-
siderably. In almost all cases, on the second day of testing, the portion of
chemical oxidation was greater than that of bacterial oxidation. But on the
second or fourth day of incubation of the bacterial culture, the indicators of
active bacterial oxidation of the n-alkane mixture were much higher than that
of chemical destruction.
In a comparison of kinetic characteristics of processes of chemical and
bacterial oxidation of diesel oil n-alkanes at different temperatures, the
activity of bacterial oxidation of individual n-alkanes at any one tempera-
ture was not observed. The bacterial and chemical degradation shows some
electivity between the adjacent terms of homologous series of n-alkanes. This
selection depends, first of all, on the hydrocarbon ratio of other homologous
series (olefines, aromatic hydrocarbons) , available in the samples examined.
It becomes evident that for laboratory study of hydrocarbon oxidation pro-
cesses in any marine area, the correct selection of oxygen sources is of
great importance.
The bacterial oxidation of n-alkanes affects the samples and influences
the substratum to a greater extent than chemical oxidation and has a greater
influence of hydrocarbons with a low boiling temperature. The variation of
n-alkanes under bacterial and chemical oxidation emphasizes the selectivity
of bacterial oxidation.
So, in the test with individual cultures, the cyclohexane disappears on
the first day of the experiment. The disappearance is explained by availabil-
ity of n-alkanes. The n-alkanes, being the growth substratum for bacteria,
promote bacterial oxidation. The chromatogram is characterized by a decrease
in the hydrocarbon peak from C^2^26 to C24H50 on the second day of experiment.
Whereas, the peak area, corresponding to C 0H22 , decreases gradually, and, to
the end of the experiment, it shows the persistence of decane to bacterial
oxidation. Chemical oxidation is revealed most strongly on the second day of
C12H24 (dodecane) , C14H3Q (tetradecane) , CigH4Q (non-decane) , C H^
(eicosane) , and C H ttetracosane) . It is evident from chromatograms that
hydrocarbons with a greater molecular weight (Ci9H40, C20H42, and C24H5C))
(Fig. 3) are greatly oxidized at all temperatures. This situation doesn't
contradict the Jobson et al. (9) data obtained when studying bacterial
oxidation of crude oil at the temperature of +4 C.
In a test with the culture mixture, the gradual decrease of peak areas
takes place in concentrations of the following normal alkanes during the
first three days: C14H30, C15H32, C16H34, C19H40, C20H42, and C24H50.
Dodecane (C16H26) decreased sharply on the second day of the experiment.
Decane (C]_0H22f doesn't change the concentration to any extent. During chemi
cal oxidation, dodecane disappeared completely on the second day of the
176
-------
TeC
•T'C
T*C
Figure 5.
Gas chromatograms of bacterial, A,B,C,D (individual culture) -and chemical,
A , B,, C,, D,, oxidation of diesel oil hydrocarbons at +20°C. AI in 0 hours,
A,' in 24 hours, B in 48 hours, C,^ in 72 hours, and A,AX in 76 hours.
-------
c<»c» c
'» i*m
c«,
| Tg«Cx>c»
5* lilU
'*S»C*«
re
T'C
*< *«
Figure 6. Gas chromatograms of bacterial A, B, C, D (mixed bacterial popula-
tion) and chemical A-^, B-^, C-, , D-^, oxidation of diesel oil hydro-
carbons at +20°C.
in 0 hr, A,A-j_ in 24 hr, B
in 96 hr.
in 48 hr, C,C, in 72 hr and D,D]_
178
-------
experiment, while hydrocarbons, from C14H30 to C24H50, disappeared gradually.
C10H22 content decreased only by approximately 70 per cent on the fourth day,
but during the first three days it was not changed (Fig. 4). These data sug-
gest the stability of C10F22 against bacterial oxidation.
It can be seen from gas chroma tograms , obtained in the experiment to
study variation of quantitative composition of diesel oil hydrocarbons by
individual cultures and culture mixture of hydrocarbon-oxidizing bacteria,
that bacterial oxidation covers hydrocarbons of a large range of molecular
weights (Figs. 5, 6). Both the example of n-alkane peaks, identified in
diesel oil, and the analysis of kinetic characteristics, show that hydrocar-
bons of one homologous series are oxidized at the same rate. Experiments
show that variation of quantitative composition is determined, firstly, by
oxidation of lightly volatile hydrocarbons of small molecular weight. During
the first days of the experiment, the principal differences of the processes
affecting diesel oil hydrocarbons were not observed. In 24 hours the quantity
of normal alkanes decreased relative to compounds that are representatives of
other homologous series: napthenes, olefines, and aromatic compounds. It was
confirmed by data from fluorescent chromatography , that characterized the
variation of group hydrocarbon composition.
On the fourth day of the experiment, n-alkanes with longer hydrocarbon
chine, from C-^^A-^^, to C2QH42 , were oxidizing more actively than n-alkanes
with a shorter chain, excluding CigH4o, which was practically not assimilated
at all during the experiment. This change was confirmed by the value of the
initial rate of oxidation for C^gH^, calculated from the kinetic equation
and equal to 0.18 mg day .
Chemical oxidation is revealed in the concentration variation of hydro-
carbon with a low boiling point and simultaneous decrease of all diesel oil
hydrocarbons .
At +10°C and +2°C, the character of the bacterial oxidation differs con-
siderably from biodegradation at +20°C, and it is revealed by intensive oxi-
dation of n-alkanes in series from C^E^Q, to C2oH42- Analysis of kinetic
characteristics shows that the constant of the oxidation rate is practically
linear, depending on the number of carbon atoms in n-alkanes.
Chemical oxidation in experiments at low temperatures shows an insigni-
ficant percentage and doesn't reveal visual variations of chroma tograms .
In general, the analysis of gas chromatograms illustrates the quantita-
tive and qualitative variations and relative oxidation rate of the diesel oil
hydrocarbons. It is also the base for the calculation of the kinetic charac-
teristics of hydrocarbon oxidation processes.
As has been pointed out above, the main purpose of the investigation of
the destruction process of hydrocarbons of oil origin was made to determine
the rate of these processes for subsequent estimates on the possibility of
self purification, and prediction of the dynamics of pollution levels.
179
-------
Unfortunately, available data on hydrocarbon oxidation rates are not
comparable. The main difficulty of comparing the analysis data from different
investigations is in the distinction of methods used for estimating the oxi-
dation processes of oil and oil products. Traditional investigations of bac-
terial activity by means of studying the quantity and rates of microorganisms
generated, measuring the rates of oxygen consumed, carbon dioxide extracted,
and determination of decreasing oil concentration in the incubation period,
are the most widespread methods used. For estimating the metabolism rate in
the process of biological transformation of hydrocarbons, different numerical
methods are used.
The kinetic description of hydrocarbon oxidation processes (as in any
other organics) is of great importance. In practice, it reflects the com-
plicated picture of interaction between chemical and biological factors. The
equation of the first order is frequently used for kinetic calculations of
mixture-oxidation in near-bottom waters. Experimental observations show that
hydrocarbon oxidation, and oxidation of other organics in seawater, does not
proceed at the same rate. It is evident from the analysis of hydrocarbon
oxidation dynamics that the process develops intensively in the initial
period of incubation. On the other hand, a delay of some days occurs (induc-
tion) with the subsequent activation of oxidation. After the incubation
period, when there is no marked, analytically fixed oxidation of mixtures, the
autocatalitical character of the process is revealed. In such a regime of
oxidation processes the first order reaction equation doesn't describe the
experimental data for the whole investigation period.
Experimental investigations have found that hydrocarbon oxidation
dynamics show S form of process development. The equation of A type (2 )
is the most convenient for the analysis of this type of curve.
The equation in integral form allows us to calculate the hydrocarbon
concentration for the any moment of time. The integral form of autocatalitic
equation is:
(C) = (Co)- IB fe""3it „»
1 + ?0ewt. (1)
The differential form is:
Idle
= % (|C0|-X)(|B|o+X), (2)
where (CQ) = initial hydrocarbons content, mg/£.
(C) = hydrocarbon concentration to moment of time, mg/£.
Kk = the rate constant of the second order.
B° I = concentration of intermediate products, equal numerically to
the ratio K^/Kk,
X = the quantity of oxidized hydrocarbons, equal to Co - C
where W = Kfc( B °+|Coo|), K±= Kk |B °. (3)
Coo = maximum oxidation.
W1K1 = tne rate constant of the first order, day :
The initial rate of oxidation mg/£ per day:
180
-------
VX = K^Coo) (4)
Investigation of processes of chemical and bacterial oxidation of diesel
oil hydrocarbons and n-alkanes in diesel oil under different temperature con-
ditions allowed us to determine the influence of temperature on the kinetics
of bacterial and chemical oxidation of n-alkanes. The validity of one of the
most important temperature characteristics, E, the activation energy, was
estimated by kinetic characteristics obtained under different temperature con-
ditions for diesel oil hydrocarbons.
On the basis of all the kinetic calculations of the rate constants for
bacterial and chemical oxidation of diesel oil hydrocarbons and n-alkanes in
different hydrocarbon mixtures, the values of one of the most important tem-
perature characteristics, activation energy, were obtained. These values
allowed us to calculate the rate constant of oxidizing processes at differ-
ent temperatures. The kinetic characteristics can be useful for process
modeling under field conditions. They also permit an approach to forecasting
selfpurification possibilities of marine ecosystems.
Thus, through the example of hydrocarbons of oil origin, we found that
the pollutant degradation processes are extremely complex and depend con-
siderably on concrete physical-chemical and microbiological conditions, The
pollutants are characterized by their own kinetics and degradation rate under
the influence of prevailing processes. Therefore, further efforts should be
made to study the parameters characteristic of every category of pollutant.
Thtir transformation and degradation in multicomponent mediums should be des-
cribed.
The exceptionally large space scale of spreading pollution, the charac-
teristics of its distribution, depending on water circulation, and the con-
dition of degradation, suggest a number of questions to be answered about the
problem of pollution in the world's oceans. Among them, the development of a
global system of observation of chemical pollution in the marine environment
is an initial step in development of a global system of observation of ©co-
logieal consequences of marine pollution.
Considerations expressed in this article are the elements relating to the
scientific principles of development of such a system.
181
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REFERENCES
1. Zubakina, A.N., A.V. Tsyban, S.P- Bariniva, and I.M. Mikhaleva. 1975.
On the Role of Physico-chemical and microbiological Factors in the
Destruction Processes of Hydrocarbons of Oil Origin. Proceedings
of I All-Union Symposium, Oceanographical Aspects of Water Protec-
tion from Pollution. M., pp. 66-72,
2. Leonov, A.V. 1974. Generalization, Typification, and Kinetic Analysis
of Curves of Oxygen Demand on the BOD-experiments Data. Okeanologiya,
T. 14, N.I., p. 82.
3. Oradovski, S.G., A.I. Simonov, A.A. Yustchak. 1975. Investigation of the
Character of Chemical Pollution Distribution in the Gulf Stream Area
and its Influence on the Primary Productivity of the Oceanic Waters.
Meteorologiya I Hydrologiya, N. 2, pp. 48-58.
4. Simonov, A.I., Y.S. Tokuev, and V.S. Chernyshov. 1972. On the Free-
radical Reactions of Physico-chemical Processes of Natural Water
Self-purification. The Report of VI All-Union Science Conference
on Sea Chemistry, AN USSR, M., pp. 55-56.
5. Simonov, A.I., and L.K. Lykova. 1972. Influence of Some Physico-chemical
Factors on the Rate of Phenol Destruction in Brackish Waters.
Proceedings of IV All-Union Symposium on the Modern Problems of Self-
purification and Regulation of Water Quality. Tallin, 25 October,
1972, pp. 34-38.
6. Simonov, A.I. 1973. In: Foreword, Sea Pollution by Oil. L.,
Hydrometizdat. pp- 5-17.
7. Simonov, A.I., S.G. Oradovski, and A.A. Yustchak. 1974. The Modern
State of Chemical Pollution of the North Atlantic Waters. Meterolo-
giya I Hydrologiya, N.3. pp. 61-69.
8. Tsyban, A.V., A.N. Zubakina, V.V. Il'inskij, and S.P. Barinova. 1975.
Modelling of Microbial Oxidation Processes of Oil and Diesel Oil.
Proceedings of the I All-Union Symposium, Oceanographical Aspects
of the Water Protection from Chemical Pollution, M. pp. 191-194.
9. Jobson, S., F. Cook ,and D. Westlake. 1972. Microbial Utilization of
Crude Oil. Appl. Microbiol., 23, v.6, pp. 1082-1089.
182
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MONITORING OF MARINE ENVIRONMENT AS AN INFORMATION
BASIS FOR ECONOMIC-ECOLOGICAL CONTROL
M. T. Meleshkin, A. I. Simonov, A, M. Bronfman,
V. E. Glushkov, and A. L. Suvorovsky
Economics Institute of the Ukrainian Academy of Sciences
Odessa
Urgent problems arising in developing a long-term strategy of exploiting
and protecting the marine environment are part of the general problem known as
"man and surrounding medium," and, naturally, these problems should be
investigated and solved in conjunction with already known methodological
approaches.
It is evident, however, that continuity in this respect cannot be com-
plete because the marine environment, as an object and subject of anthropo-
genic influences, is remarkable for its specific nature. At the same time,
it may be possible to offer a general methodological conception which is
equally acceptable when developing a theoretical foundation while retaining
measures for nature protection, irrespective of the field of application. To
fully attain the objectives mentioned above, in our opinion, it would be wise
to use a conception of unity of economy and ecolcgy within which any process
of employment of natural environment is considered as an interchange of matter
and energy between such subsystems as "economy," meaning the economic activity
of man, and "environment" presented by both abiotic and biotic complexes.
Insoluble ties between these subsystems unite them into a common economic-
ecological system.
The major premises and principles of the proposed conception are outlined
below:
1. The scale and rate of modern productive forces are objective factors
leading to rapid increase of anthropogenic loads on the biosphere which are
comparable with the scale and rate of natural influences. The evaluation and
prediction of possible changes because of these factors, as well as the devel-
opment of control systems for nature protection, cannot be accomplished by
conventional isolated methods of economic and ecological analysis. Naturally,
a need arises for the development of new qualitative methods for investigation
and control based on the knowledge of the laws of behavior of the complicated
economic-ecological systems.
2. The methodological basis for determining the irregularities of
development of economic-ecological systems should be the consideration of such
peculiarities of the natural environment as its inertia, ability for adapting
and self-adjustment, and, finally, the probability character of its parameters
183
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and processes.
3. As a basis for economic-ecological planning, use should be made of
the principles of staging, and territorial differentiation and complexity, in
contemplating the combined use and reproduction of natural resources (1, 2).
4. Solving the problem of optimum interaction in the "economy-environ-
ment" system demands a complex approach to controlling the subsystems with the
aim of attaining their balanced development. Necessity for such an approach
is emphasized by the recently observed processes of intensive mutual penetra-
tion of the economy and ecology at the local, regional, subregional, and global
levels.
5. Unity of the economy and ecology stems not only from their interre-
lation, but also from the possibility of attaining some, or other, social aims
by the simultaneous controlling of both the economic parameters and the state
of the environment.
ECONOMIC ZONING
In the application of our theme, the principal task in controlling the
processes of functioning of the economic-ecological system, is the attainment
of the necessary conformities in the interchange of matter and energy between
economy and the marine environment.
The sea and, especially, oceanic biogeocenoses that have a certain resis-
tance to external influences and considerable capabilities of adapting allow
man, within certain limits, to change the conditions of the surrounding
medium. However, these changes should not go over the boundaries beyond which
breaks the established links intrinsic in biogeocenosis ao a system in a state
of dynamic equilibrity.
In the present state of social development, the threat of sueh a situa-
tion is real enough. In a large number of watar areas, the anthropogenic
transformation ©f the ecological systems is an accomplished fact. Chemical
pollution plays a dominant role in this process.
It is well known that the effectiveness of modern production, with
respect to utilization of resources, remains at a very low level. A finished
article contains, on the average, about 5 to 10 psr cent of the raw materials
used in its construction (3). The remaining 90 to 95 per cent, in th© form of
waste, is dumped into the surrounding medium. The greater partof these wastes
is being accumulated in the world's oceans, especially in shelf waters and
inland seas.
The ever increasing amount of anthropogenic-wastes dumped into the marines
environment, and areas connected with it, causa development of unfavorable
ecological conditions which sharply increase the problem and the necessity
of active and purposeful control of the situation.
Objective control of the complicated, dynamically developing economic-
ecological systems can only be accomplished by use of all information allowing
184
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Developing situations to be predicted, planned decisions to be made, and the
criteria of cost, time, effectiveness, and risk evaluated.
The character of the information obtained should also be guided by a pro-
gram relative to control purposes. Such a program can generally be formulated
as bringing anthropogenic influences in agreement with the adapting capacity
of the environment.
Reaching such an agreement is a problem of a very complicated nature.
Regarding chemical pollution, such an agreement contemplates the forming of
balanced economic-ecological systems in which the amounts of toxic wastes from
the economic activity of man would be properly rated with respect to the
potential detoxicating abilities of the receiving water basins (which, at the
same time, would have no harmful effect upon the biogeocenoses). In fact, it
would be necessary to rate maximum permissible dumpings (MPD) in considering
the marine environment's self-cleaning potential (SCP) and subsequent step-
by-step attainment of such quantitative relations between the two which would
guarantee a stable content of pollutants at a level not exceeding maximum per-
missible concentrations (MFC).
The proposed outline of the problem is a further development of the
scientific basis of monitoring put forward by Yu. A. Izrael at the First
Soviet-American Symposium on Comprehensive Analysis of the Environment (4).
This statement of the problem has many points in its favor.
First, it contemplates passing from studying the state of pollution in
the marine environment to studying the processes of its dynamics, depending on
determining factors. The principal factor is the development of productive
forces and the whole complex of characteristics forming the self-cleaning
potential of the environment. It is important that the latter circumstance
allows respective links between the "economy" and "environment" subsystems to
be established. Such subsystems are required for the purpose of control and,
particularly, to solve the immediate problem of the most reasonable redis-
tribution of means between the measures of reducing anthropogenic dumping on
the one hand, and measures on maintaining, or even increasing, the self-
cleaning potential of the marine water areas on the other.
Secondly, the realization that the proposed approach brings about neces-
sary premises for preventive accomplishment of nature protection programs.
This circumstance is very important because no other part of the biosphere is
in such a need of preventive protection as the marine and oceanic environment.
The enormous inertia of the world's oceans makes possible a long-term and con-
cealed accumulation of polluting components and anthropogenic disturbances.
By the time the undesirable consequences of these disturbances are authenti-
cally documented and impose their harmful effect the marine environment, and
the branches of economy connected with it, their elimination will be a long-
time procedure requiring large-scale and exceptionally complicated organiza-
tional and economic efforts of society. It may also be stated, a jpriori, that
the required expenditure, in this respect, will be much greater than the cost
of preventive maintenance programs.
185
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The above-mentioned principal approach to controlling the economic-
ecological system, with reference to the protection of the marine environment
from pollution, assumes, first of all, the determination of the MPD as a con-
trolling criterion.
In a general way, the procedure of searching for the MPD includes finding
the dependence of the concentration of pollutants, (C), as a function of
space, (R) , and time, (t), on the amount of dumping, (Q), the intensity of
its dispersion as a result of turbulent diffusion, adsorption, sedimentation,
etc. (X1,X2... A^), as well as the rate of self-cleaning, (S), of the environ-
ment, i. e. :
C = C (Q,S,X1,X2 ...A^, R, t) (1)
Using the values of MFC as predetermined limits for the concentration of
pollutants (condition: C <_ MPC) , we derive the following inequality:
C = (Q,S,X1,X2 ...An, R, t) <_ MFC (2)
which is fulfilled at Q <_MPD, where MPD is determined from the relation:
C (MPD, S,Ai ,A2...An, R, t) = MPC (3)
It is of great importance that for any fixed point in the water area,
the maximum permissible dumping is limited by the self-cleaning capability
of the surrounding environment. In this connection, with the aim of making
utmost use of environmental capabilities, the value of MPD should be set
under the condition that S = SCP, so that the values of MPD, MPC, and SCP
are linked through the following relation:
C(MPD, SCP,X1,X2...An, R, t) = MPC (4)
It should be noted that in spite of the apparent simplicity of the pro-
posed formalized pattern of determining the MPD, a number of complicated
problems which must be solved arise when studying the pattern in detail. The
main problems can be shown by the following example illustrating the deter-
mination of the maximum permissible dumping with the following assumptions:
1) A function q=q(Q,^i,^2—^n» R) is given, where (q) is the rate of con-
centration change of the pollutants determined at the given point of the water
area by the dumping, (Q), and further dispersion (turbulent diffusion, adsorp-
tion, sedimentation) ;
2) The function of the self-cleaning rate is known, which depends only on
the concentration of the pollutants. This function is shown hypothetically in
Fig. 1.
In this case the dynamics of concentration may be presented by the fol-
lowing differential equation:
•q /~t ___
a£ = q(Q,Ai,A2...An, R) -S(C) (5)
186
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With initial conditions of t=0, C=C . (6)
The equation (5) with conditions (6) is solved as:
/ d° + K(Co) = t,
q-S(C)
where K(CO) is a constant of integration.
To investigate the solution obtained, let us assume that the dumping
rate is a constant value (q=const) , and the relation, S(C), at its maximum,
is approximated by the function shown in Fig. 1 by a dotted line and presented
as
S(0~- C(2C*-C),
C
where S* and C* are coordinates of the self-cleaning function maximum, or in
other words, self- cleaning potential.
In this case the solution can be written as :
/ dC _ + K(C0) = t
S*
q - c*2 C(2C*-C)
P
Passing to dimensionless variables <* = p, and T = t and introducing
a dimensionless parameter ^ = 3 , we get: C*S*
, do _ + K (<* ) = T (7)
(X-l) - («-l)
The solutions obtained as a result of integration (7) depend on the
value of ^ and are written as :
At A < i =
-A
The equation (8) confirms the self-evident conclusion that at g> 1, i.e.
under conditions when the amount of dumping at the given point of the water
area exceeds the self-cleaning potential, irrespective of the initial concen
tration C0(«o < 1, ]_) ^ there is always such an interval of time _ 1
^_B^^Mp
arctg ( OCQ_I ) at which the concentration of the pollutants becomes
impermissibly high (Fig. 2a) .
187
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From the above follows an important principal point, according to which
the value of MPD for excessively polluted water areas should be set at a sub
stantially lower level than the environmental self -cleaning potential.
At X < 1 (Fig. 2c) , depending on the initial concentration of the
pollutants, the solving of the equation (5) under initial conditions (6) is
always stable, but it may tend to two different limits:
a« o lim oc =l-Vl^ and (11)
T-X»
«" = lim oc =1
Passing from dimensionless variables to concentrations, we can write (11)
as:
C'=C*(1-'{TT*) and
As seen from Fig. 2c at Co1), then up to a certain moment T the content of pollutants in the water
area is practically stable. Such an unfavorable situation, however, is
temporary, and it reflects the inertia of the self-cleaning process. It does
not, however, signify that the relation between MPD and SCP is unfavorable.
The objective evaluation in this case demands investigation and establishment
of real values of the parameter ^.
At CQ >C"(o:o>a:") the concentration of pollutants in the water area
decreases monotonically, approaching the value C" , at which the addition con-
tent is rather high and exceeds the concentration C* corresponding to the
environmental self-cleaning potential .
As the maximum (potential) of self-cleaning is attained at a certain
concentration, (C*) , when setting up the MPD as a control criterion, it will
be necessary to also consider the value of the relation between MPC and C*.
The characteristic matrix of the possible situations arising at various values
of X, as well as various relations of CO/C*, and MPC/C*, is shown in Fig. 1.
The data shown allow a number of problems to be basically solved. These
problems are important to the selection of the strategy for the qualitative
control of the marine environment.
As seen from Table 1, under conditions of an actual situation, i.e. at
MPC < C*, the desirable result of control, maintaining the content of pollu-
tants at a level lesser or equal to the MPC, may be obtained only when X< 1
(conditions 1.4, and 1.5, Table 1).
At MPC > C* this result is obtained both at X=l (conditions 2.1, 2.2,
3.1, 3.2), and at X<1 (conditions 2.3, 3.4, 3.5). In this case, naturally, a
188
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Figure 1, Hypothetical form of relationship between
rate of self-cleaning and concentration.
Of particular interest are iituationi at which A « 1 and A < 1, In the
first case, when the intensity of dumping ii close to the self-cleaning poten-
tial of the marine environment, the dynamics of the concentration change are
determined entirely by the initial pollution of the water area (Fig. 2b). If
C0<_ C* («<_!), then the content of pollutants in the water basin rises mono-
tonieally, approaching C*(«si) asymptotically.
similar to the case, X 1,
At C0 > C* (*>!}, it grows
189
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a) r
o
r-/
\o
o
Figure 2. Change of dimensionless: variable
value of dimensionless parameter X ,
with time depending on its initial values and
-------
number of control alternatives arise which are unequal to the expenditure they
require for their fulfilment. It is especially evident that the expenditure,
being a decreasing function of the MPD, is considerably greater when A=lf than
when A<1.
TABLE 1
Increase of concentration of
pollutants 'corresponds to -marine
environment self-cleaning poten-
tial, A=l
Increase of concentration of
pollutants less than marine
environment §elf-cleaning
potential, A C* 3 MPC main-
tained at
all times
Co = C*
2
MPC can-
not be
reached
MPC main-
tained at
all times
MPC main-
tained at
all times
Co > C*
3
MPC can-
not be
reached
MPC can-
not be
reached
MPC
will be
exceeded
in a cer-
tain period
of time
Co < C*
4
MPC main-
tained at
all times
MPC main-
tained at
all times
MPC main-
tained at
all times
Co > C*
5
MPC reached
in a certain
period of time
MPC reached
in a certain
period of time
MPC maintained
at all times
It may be noted that at A=l the values of MPD and SCP are equal, and at
X< 1 the interrelation of the investigated criteria following from the equation
(11) may be written as:
MPD=SCP [1 - (1 -
MPC
C+
(12)
Actually the above-mentioned control alternatives are more numerous. As
within the conception of controlling the economic-ecological systems, there is
a basic possibility of varying the value of X, not only by varying the maximum
permissible dumpings, but also by the potential ability of the marine environ-
ment for self-cleaning. By this, it is meant that the value of the self-
cleaning potential can be increased by the adjustment of such environmental
parameters as salinity (5), content of biogenic elements, introduction of
special bacteria-destruction strains, increasing the relative share of fil-
trating organisms in the ecological system, etc. Thereby, under the condition
of A=MPD/SCP-const, owing to the increase of the environmental self-cleaning
potential, the possibility arises of increasing the MPD and, accordingly, re-
ducing the costs for its attainment and maintenance. In this case, naturally,
a number of control alternatives arise, including the possibility of choosing
an optimum method according to the minimum total expenditure criterion. The
practical solution of this problem is of particular interest and should be the
subject of an independent investigation.
191
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The foregoing indicates that, for the qualitative control of the marine
environment, it will be necessary to extend information units of chemical
pollution monitoring by introducing into the system some defining factors of
a number of parameters, such as:
• quantity and composition of anthropogenic wastes dumped into the
sea from local polluting sources;
• a set of parameters allowing an estimate of the processes of dispersion
of pollutants as a result of turbulent diffusion, adsorption, and sedimenta-
tion;
• concentration of pollutants, (C*), corresponding to the maximum of the
environmental self-cleaning ability (S*).
A distinct position is thereby taken by the experimental determination of
the form of the function S(C) for the water areas investigated, or separate
chambers characteristic of them.
The solving of the latter problem is possible in two ways. The first
way consists of a detailed study of all the defining factors with subsequent
development of simulated models of the process. The second, and a more
acceptable, way is to select a system of integrating indices allowing a
macro-description of the function being sought. Substantiating the system
of these indices is a separate task which is beyond the scope of this report.
However, some problems to be proposed are the energy of activation and ths
constant of the dissociation rate of pollutants, which are rather easily
determined by experiment.
It is evident that within the scope of a single paper it is impossible
to explain all the points of such a complicated problem as the qualitative
control of the marine environment. The interpretations set forth in the
foregoing lines consisted only of shaping the principal aim of control,
proving the basic possibilities, and determining the ways of attainment of
control in practice. The final stagt, completing this work, seems to ba thg
elaboration of a system for economic-ecological planning and control.
The proposed schematic diagram (Fig. 3) allows us, firstly, to trace the
place of monitoring and, second, to determine ths whole complex of require-
ments imposed upon this control on the part of the system as a whole, and,
finally, to show the relationship between the information flows within the
system.
As seen from Fig. 3, the functional scheme of economic-ecological control
is proposed to be built in the form of four units: monitoring, (1); ecological,
(2); and economic, (3); predicting, and economic-ecological planning proper,
(4).
The object of control, contemplated as a unified economic-ecological
system, is represented in the diagram in the form of two units:"economy",
(5); and "environment", (6). Considering the nature of links between them it
seems feasible to organize monitoring comprising three kinds of observations
192
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kD
00
I BiillZATIOH 0^ iCOEPTEJ) VABIWT 1
Figure 3. Schematic diagram of economic-ecological planning system.
-------
necessary for controlling purposes, viz.:
£55 - concerning the nature of anthropogenic disturbances;
£55 - concerning the physical, chemical, and biological parameters of
the state of environment included in the production function of consumer
goods.
If, for denoting the routine state of the environment the above informa
tion is sufficient, the predicting purposes require the knowledge of the
transformation mechanism of anthropogenic disturbances in the environment.
The information basis for modelling, and prediction in this case, may serve
the knowledge of the variations of the environmental parameters both as a
result of anthropogenic activity and the climatic conditions . It is this
kind of information, denoted as Agg , that is shown on the diagram.
Under the requirements of information on the part of the observation
system, £55 , this information is necessary for the determination of the
dependence of industrial activity effectiveness on the state of the environ-
ment. This dependence can be written in the form of production functions as
follows :
P = f (F]_, F2...FK) ^(^^...ccn) (14)
where: P is the result of the operation of an enterprise (finished product,
production costs, effectiveness, etc.);
f(F]_, F2-..%) is a function describing the dependence of the results
on the economic factors (basic funds, labor expenditure, etc.);
ty ("I 'CX2 • • •ccn) is a function of influence of the state of the environment
determined unequivocally as a set of physico-chemical, dynamic, biological,
and similar parameters, {=i} (salinity, temperature, concentration of adequate
ingredients, dynamics of flows, streams, etc.).
Monitoring the marine environment determines the values of the ecological
parameters {<*i}. At the same time, for plotting production functions such as,
(14) , special information is required as to the values and dynamics of the
economic factors (P , F]_ , F2...F^). This involves the necessity to also
supplement monitoring with the observation system A55 .
Thus, it is proposed to single out four basic systems to observe the
state of the environment and economic activity, having unified them by the
concept of economic-ecological monitoring (subsystem 1, Fig. 3) .
As may be seen from the diagram, the economic-ecological monitoring
includes the following functional units: 1.1 and 1.2 are the information
processing systems A56, and A66, for clarifying the functional relations
between the state parameters subjected to anthropogenic disturbances.
1.3 are the information processing systems A55, and ASS, for determining
the quality of the environment, i.e. evaluation of its state, accomplished by
194
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the respective consumer.
If the content of units 1.1 and 1.2 is sufficiently evident, the concept
of the equality of the environment requires some clarification. Actually,
the quality of the environment is an economic evaluation of the compliance of
its state with the requirements of the respective consumer. Thus, a certain
state of the environment may be satisfactory for one consumer, and unsatis-
factory for another.
When considering the requirements of society in all its diversity, it
may be feasible to single out three types of marine water areas: protected
zones, health resort zones, and regions of high economic use. Accordingly,
the concept of quality of the marine environment is different for these types
of water areas. In the first case, the quality of the environment is evalu-
ated by the degree of the state of preservation of the ecological systems.
In the second case, the quality is determined by the degree of compliance with
the social and hygienic requirements. And, finally, in the third case, the
economic evaluation of the environmental quality may be defined by comparing
the current effectiveness of its use with the maximum possible effectiveness.
The subject of this investigation, in our view, may be the production func-
tions as in (14) .
In the ecological prediction subsystem (2) , various environmental
behavior models (unit 2.1) are shaped according to the information (1.1), the
adequacy of which being checked by means of the retrospective and current data
on the strength of the information 1.1 and 1.2. The final functioning result
of the subsystem (2) is the elaboration of the environmental system of models
(2.2), allowing the dynamic of the basic parameters of the state of the envi-
ronment to be predicted. In supplement to the problems connected with the
pollution of the marine environment, this unit includes, as a minimum, the
modelling of the processes of disperson of pollutants, self-cleaning, etc.,
with their subsequent unification into a common concentration dynamic model,
similar to that described by the equation (5) .
In the economic prediction subsystem, (3) , variants of economic activity,
(3.3), are elaborated on the basis of the development of requirements, (3.2),
providing for their statisf action.
The specific feature in operating the economic-ecological systems is that
the interaction of the "economy" and "environment" takes place at a level of
separate enterprises in specific regions. Consequently, the operation of this
unit is accomplished at two levels: macroeconomic and microeconomic, the
latter comprising production functions.
On the basis of the production functions for each of the variants, cer-
tain requirements for the parameters of the environmental state are formed.
The list of these parameters should be included in any monitoring program
concerning the observation system
Information on the extent and nature of the anthropogenic disturbances,
deposited with the unit, 3.4, is determined by considering the technology and
the volume of output (defined by the respective variants of economic activity).
195
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The information worked out by the unit, 3.4, is employed in the environ-
mental modelling (unit 2.2). In its turn, the information of unit 3.3, in
conjunction with the prediction of the environmental state (output of unit
2.2), is the basis for modelling the quality of the environment (which takes
place in unit 4.3).
In the subsystem 4, the conjugation of the variants of economic activity
with the predicted state of the environment is accomplished, i.e. the econom-
ic-ecological planning proper. For this purpose, provision is made for a
unit, (4.2), in which various criteria and limitations of the water areas with
different characters of employment are worked out. The division into dis-
tricts, required for this purpose, is performed in unit 4.1, on the basis of
the information data on the current state and quality of the marine environ-
ment, (unit 1.3), and the society requirement prediction (unit 3.1) with
respect to the contemplated character of utilizing the water areas.
The problem of choosing the criteria of economic-ecological control is
a complicated and independent task. Solution of this problem is not connected
with the problems of monitoring of the marine environment. Establishment of
scientifically founded limitations is, as follows from the foregoing lines,
one of the main functions of chemical pollution monitoring. Returning to
Table 1, we want to recall that the establishment of the MFC and MPD as limi-
tations of economic-ecological control is determined, principally, by the
value of the self-cleaning potential (SCP), and also by the values of Co,
C*, and finally, by the relation between MPC and C*.
In this way, requirements of economic-ecological control, with the aim
of protecting the marine environment from pollution, sets up a monitoring
problem to determine the fields of C0, C* and SCP for various water areas of
the world's oceans. Solving this problem will permit their division into
districts and subsequent forming of a differential strategy to permit balanced
development of regional economic-ecological systems.
Only by applying the described approach to control of these systems of
ever-growing scale can chemical pollution of the marine environment be pre-
vented.
It is quite evident that the statements put forth in this work lay no
claim to being complete, but are only contemplations for more important
problems which should be solved within the scope of protecting the sea
resources from their quantitative and qualitative exhaustion. Many of the
points are described in the form of problems, and their discussion, develop-
ment, and realization are contemplated by us as very perspective tasks.
196
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REFERENCES
1. Meleshkin, M.T. 1975. Fundamentals of Programmed Planning of Economic
Exploitation of the World Ocean. In: Problems of Sea Economy, is.4,
Odessa.
2. Meleshkin, M.T, and A.L. Suvorovskiy, et al. 1974. Methodological Funda-
mentals of the World Ocean Economy. Vestnik No. 12, Ac.Sci.USSR.
3. Ananitchev, K.V. 1974. Problems of Environment, Energy and Natural
Resources, Moscow, Progress.
4. Izrael, Uy.A. 1975. Complex Analysis of Environment. Approaches to
Determining Permissible Loads on Environment and Substantiation of
Monitoring. In: Comprehensive Analysis of the Environment,
Gidrometizdat, Leningrad.
5. Bronfman, A.M. 1976. Alternative Solving of Economic-Ecological
Problems in the Azov Sea Basin. In: Problems of Sea Economy is. 5,
Odessa.
197
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APPENDIX
PROTOCOL OF THE WORKING MEETING OF SOVIET AND AMERICAN
SPECIALISTS ON THE RESULTS OF THE SOVIET-AMERICAN INTERCALIBRATION OF
METHODS OF DETERMINING OIL AND OIL PRODUCTS IN SEAWATER DURING AN
EXPEDITION AT SEA
Odessa. May 24, 1977
After discussing the results of the intercalibration of methods for
determining oil and oil products in seawater during the voyage of the research
vessel Musson in the Atlantic Ocean (December 1975 to January 1976), the
participants note that:
1. Standard solutions exchanged and analyzed by using the infrared method
show nearly identical results.
2. The infrared red absorbtion at 2930 cm of the CCL4 used by the
American and Soviet sides prove also to be nearly identical.
3. The data on oil concentrations in some extracts made during the cruise
with an OIL 102 Yanagimoto Oil Analyser are similar to results obtained for
unprocessed samples in land-based laboratories in the U.S. and U.S.S.R.
4. Some discrepancies in the analysis of processed samples were probably
caused during individual stages of analyses (sampling methods, extraction,
vacuum concentration, drying of the extract, or column chromotography). In
addition, the seawater divided on board into two parts may have been in homo-
genous in oil concentration. These variables cannot be controlled at sea.
5. Both sides think that it is advisable to carry out the second stage
of intercalibration of methods for determining oils and oil products under
laboratory conditions. During this stage, both sides will compare all samp-
ling procedures. Prior to the laboratory intercalibration, it is necessary
to complete a detailed program for this work.
Both sides will exchange draft programs before October 1977. The pro-
gram should be finalized and exchanged under the auspices of the Joint U.S.-
U.S.S.R. Committee on Cooperation in the Field of Environmental Protection by
January 1978. Both sides propose that this laboratory work will be carried
out in the U.S. during the second half of 1978.
198
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6. A joint report of the results of oceanic samples and laboratory
intercalibration will be made after completion of the laboratory work.
7. Data from the joint cruise will be kept in the individual laboratories
in the U.S. and the U.S.S.R.
U.S. Side
Dr. T. Duke
Dr. R. Hittinger
U.S.S.R. Side
Dr. A. Simonov
Dr. S. Oradovski
199
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
_EPA-600/9-78-038
4. TITLE AND SUBTITLE
FIRST AMERICAN-SOVIET SYMPOSIUM ON CHEMICAL POLLUTION
OF THE MARINE ENVIRONMENT
5. REPORT DATE
6. PERFORMING ORGANIZATION CODE
3. RECIPIENT'S ACCESSION NO.
7. AUTHOR(S)
Compiled by Thomas W. Duke
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Research Laboratory
Gulf Breeze, FL 32561
10. PROGRAM ELEMENT NO.
1BA608
11. CONTRACT/GRANT NO.
Joint U.S.-U.S.S.R. Project
VI-2.1
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Research and Development
Environmental Research Laboratory
Gulf Breeze, Florida 32561
13. TYPE OF REPORT AND PERIOD COVERED
Final, May 24-28, 1977
14. SPONSORING AGENCY CODE
EPA/600/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
This symposium, organized under a U.S.-U.S.S.R. Environmental Agreement
(Project 02.06-21) , focuses on the impact of chemical pollution on the world's
oceans. Soviet and American specialists discuss the fate of heavy metals in
estuaries and the Gulf of Mexico; transport of natural radionuclides in shelf waters
of the eastern U.S.; the distribution and dynamics of trace metals in pore water and
sediment; biogeochemical research on metals in the world's oceans; monitoring chemical
pollution and forecasting its biological consequences; arsenic, antimony, and mercury
in seawater; pollution of the Caribbean Basin; oil and oil products in surface waters
of the Atlantic, Pacific, and Indian Oceans; the forms of heavy metals in seawater
(e.g. mercury); methods of sampling water from the ocean surface microlayer and the
technical composition of the microlayer; a method for determining mercury; scientific
aspects of marine pollution problems; and the management of the quality of the marine
environment. Publication of the proceedings held May 24-28, 1977, in Odessa, U.S.S.R.,
is in compliance with the Memorandum from the 4th Session of the Joint U.S.-U.S.S.R.
Committee on Cooperation in the Field of Environmental Research.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Oil recovery
Nuclides
Chemical reactions
Water pollution
Water resources
Nuclear fuels
Metal containing organic compounds
Radioactive isotopes
Oceanographic surveys
Biogeochemical research
U.S.-U.S.S.R. Agreement
in the Field of Environ
mental Protection
Fate of heavy metals
Ocean surface microlayer
06/06
07/04
- 08/01
08/04
11/06
11/08
18/07
18. DISTRIBUTION STATEMENT
Release to public
19. SECURITY CLASS (ThisReport)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
21. NO. OF PAGES
199
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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